Refine
Year of publication
Document Type
- Doctoral Thesis (220)
- Part of Periodical (83)
- Master's Thesis (80)
- Bachelor Thesis (44)
- Diploma Thesis (27)
- Study Thesis (11)
- Conference Proceedings (9)
- Habilitation (4)
- Article (3)
- Book (1)
Language
- English (484) (remove)
Keywords
- Pestizid (8)
- Pflanzenschutzmittel (6)
- Software Engineering (6)
- Internet of Things (5)
- Bluetooth (4)
- Semantic Web (4)
- ecotoxicology (4)
- ontology (4)
- risk assessment (4)
- soil organic matter (4)
- API (3)
- Biodiversität (3)
- E-KRHyper (3)
- Enterprise 2.0 (3)
- Insektizid (3)
- Knowledge Compilation (3)
- Landwirtschaft (3)
- Maschinelles Lernen (3)
- Nanopartikel (3)
- OWL (3)
- OWL <Informatik> (3)
- Ontologie <Wissensverarbeitung> (3)
- Ontology (3)
- Pesticides (3)
- Risikoanalyse (3)
- Systematik (3)
- UML (3)
- University (3)
- agriculture (3)
- classification (3)
- computer clusters (3)
- model-based (3)
- pesticide (3)
- pesticides (3)
- virtual reality (3)
- Abduktion <Logik> (2)
- Abwasserreinigung (2)
- Akzeptanz (2)
- Annotation (2)
- Anpassung (2)
- Beschaffung (2)
- Bestäubung (2)
- Bildverarbeitung (2)
- Bodenchemie (2)
- Campus Information System (2)
- Cloud Computing (2)
- Computer Graphics (2)
- Computergraphik (2)
- Computersimulation (2)
- Data Mining (2)
- Diffusion (2)
- Ecotoxicology (2)
- Equality (2)
- Feldsaum (2)
- Formale Ontologie (2)
- GIS (2)
- Genetische Variabilität (2)
- Graphik (2)
- Grounded Theory (2)
- Habitat Fragmentation (2)
- Kakamega Forest (2)
- Kognitive Linguistik (2)
- Line Space (2)
- Linked Open Data (2)
- Logistik (2)
- Metamodel (2)
- Modellgetriebene Entwicklung (2)
- Nanoparticles (2)
- Netzwerk (2)
- OpenGL (2)
- Petri Nets (2)
- Petri-Netze (2)
- Propagation (2)
- RDF (2)
- Risikobewertung (2)
- Risikomanagement (2)
- Schlussfolgern (2)
- Sediment (2)
- Serviceorientierte Architektur (2)
- Simulation (2)
- Softwaretest (2)
- Sozialpsychologie (2)
- Taxonomie (2)
- Taxonomy (2)
- Theorem Proving (2)
- Umweltpsychologie (2)
- Umwelttoxikologie (2)
- Umweltwissenschaften (2)
- Usability (2)
- Volumen-Rendering (2)
- Wastewater treatment plants (2)
- Wikipedia (2)
- Wirbellose (2)
- XML (2)
- aquatic ecotoxicology (2)
- aquatic macrophytes (2)
- artificial neural networks (2)
- constraint logic programming (2)
- decomposition (2)
- description logic (2)
- ecotoxicity (2)
- emic-etic (2)
- eye tracking (2)
- framework (2)
- freshwater organisms (2)
- governance (2)
- hybrid automata (2)
- invertebrates (2)
- micropollutants (2)
- mobile phone (2)
- modelling (2)
- monitoring (2)
- mosquito control (2)
- multi-agent systems (2)
- multimedia metadata (2)
- optimal control (2)
- parallel algorithms (2)
- probability propagation nets (2)
- risk (2)
- semantics (2)
- simulation (2)
- social media (2)
- social simulation (2)
- soil water repellency (2)
- sorption (2)
- streams (2)
- tracking (2)
- traits (2)
- transformation (2)
- visualization (2)
- wastewater treatment (2)
- Ökosystem (2)
- Ökosystemdienstleistung (2)
- Ökotoxikologie (2)
- Neuronales Netz (1)
- 101companies (1)
- 1H-NMR Relaxometry (1)
- 2019 European Parliament Election (1)
- 8C model (1)
- ABox (1)
- API Analysis (1)
- API Migratiom (1)
- API analysis (1)
- API-Analyse (1)
- AUTOSAR (1)
- Abbildung <Mathematik> (1)
- Abdrift <Pflanzenbau> (1)
- Absolutismus (1)
- Abwasser (1)
- Abwasserbehandlung (1)
- Acceleration Structures (1)
- Ad-hoc-Netz (1)
- Adaptation (1)
- Adaptive Services Grid (ASG) (1)
- Adobe Flex (1)
- Africa (1)
- Afrika (1)
- Agenten (1)
- Agentenorientiertes Software Engineering (1)
- Agents (1)
- Agrarlandschaft (1)
- Agriculture (1)
- Agrochemikalien (1)
- Aktionsart (1)
- Aktiver Wortschatz (1)
- Algolib (1)
- Algorithm Engineering (1)
- Algorithmische Geometrie (1)
- Amazon Mechanical Turks (1)
- Amazonia (1)
- Amazonien (1)
- Amphibia (1)
- Analysis of social platform (1)
- Android <Systemplattform> (1)
- Aphid predator (1)
- Aquatic Ecotoxicology (1)
- Aquatic Guidance Document (1)
- Aquatic ecology (1)
- Aquatische Makrophyten (1)
- Aquatisches Ökosystem (1)
- Araneae (1)
- Architektur <Informatik> (1)
- Archivierung (1)
- Articles for Deletion (1)
- Artificial Intelligence (1)
- Artificial Neural Networks (1)
- Arzneimittel (1)
- Arzneistoffe (1)
- Aspekt <Linguistik> (1)
- Association Rules (1)
- Auchenorrhyncha (1)
- Auditing (1)
- Augenbewegung (1)
- Augmented Reality (1)
- Ausbreitung (1)
- Auslese (1)
- Auswahl (1)
- Automated Theorem Proving (1)
- Automated Theorem Proving Systems (1)
- Automatische Klassifikation (1)
- Automatisches Beweisverfahren (1)
- Automotive Systems (1)
- Autoritarismus (1)
- Avatar (1)
- B2B Integration (1)
- BPM (1)
- BPMN (1)
- BPMS (1)
- Bach (1)
- Basic psychological needs (1)
- Bayes Procedures (1)
- Bayes-Netz (1)
- Bayesian Networks (1)
- Beaconless (1)
- Bebauungsdichte (1)
- Bedarfsanalyse (1)
- Bedarfsforschung (1)
- Bedrohte Tiere (1)
- Bees (1)
- Befahrbarkeit (1)
- Belebtschlamm (1)
- Belief change, concept contraction, EL (1)
- Benetzung (1)
- Benutzerverhalten (1)
- Beruflicher Kontakt (1)
- Beschichtung (1)
- Beschreibungslogik (1)
- Bestäuber (1)
- Beta-Blocker (1)
- Beta-Diversität (1)
- Bewertungskriterien (1)
- Bienen <Familie> (1)
- Big Five (1)
- Bildanalyse (1)
- Bildsegmentierung (1)
- Bilingualer Unterricht (1)
- Bioassay (1)
- Biodiversity (1)
- Biohydrogel (1)
- Biometric Authentication (1)
- Biopolymere (1)
- Biotransformation (1)
- Biozide (1)
- Bipartiter Graph (1)
- Blickbewegung (1)
- Blickpunktabhängig (1)
- Blog marketing (1)
- Boden (1)
- Bodenphysik (1)
- Bodenwasser (1)
- Bodenökologie (1)
- Bombina variegata (1)
- Border Gateway Protocol (1)
- Border Gateway Protocol 4 (1)
- Budongo Forest (1)
- Building Performance Evaluation (1)
- Business Collaboration (1)
- Business English (1)
- Business Process Management Recommender Systems Survey (1)
- Business Process Modeling (1)
- Business Rule Bases, Inconsistency Measurement (1)
- Bärlappe (1)
- Bürgerbeiteiligung (1)
- C++ (1)
- CSCW (1)
- Calcium (1)
- Calculus (1)
- Carry-over effects (1)
- Case Study Analysis (1)
- Cashew-Sektor (1)
- Casual Games (1)
- Cations (1)
- Challenges (1)
- Chaos (1)
- Cheilolejeunea ; continental tropical Africa ; rainforest (1)
- Chemische Abwasserreinigung (1)
- Chironomus riparius (1)
- Chromatographie (1)
- Climate (1)
- Climate anxiety (1)
- Climate denial (1)
- Cloud Point Extraction (1)
- Clustering coefficient (1)
- CodeBlue (1)
- Cognitive functions (1)
- Cold Chain (1)
- Collaboration (1)
- Coloskopie (1)
- Communication Networks (1)
- Computational Toxicology (1)
- Computational biology (1)
- Compute Shader (1)
- Computer Security (1)
- Computer Vision (1)
- Computeranimation (1)
- Computersicherheit (1)
- Computerspiel (1)
- Computertomografie (1)
- Computervisualistik (1)
- Conceptual Metaphor Theory (1)
- Conference (1)
- Connected Vehicles (1)
- Conservation (1)
- Consumer behaviour (1)
- Container Entity Modell (1)
- Content Analysis (1)
- Content Management (1)
- Content and Language Integrated Learning (1)
- Content and Language Integrated Learning (CLIL) (1)
- Context-aware processes (1)
- Core Ontology on Multimedia (1)
- Core Ontology on Multimedia (COMM) (1)
- Core Self-Evaluations (1)
- Crayfish (1)
- Crayfish plague (1)
- Creativity (1)
- Criteria Matrix (1)
- Crowdsourcing (1)
- DMN (1)
- DPLL procedure (1)
- DRIFTS (1)
- DTI (1)
- Daphnia (1)
- Daphnia longispina (1)
- Daphnia longispina complex (1)
- Daphnia longispina-Komplex (1)
- Darmpolyp (1)
- Data compression (1)
- Data manipulation (1)
- Data protection (1)
- Datenaustausch (1)
- Datenkompression (1)
- Datenschutz (1)
- Decision-support (1)
- Decodierung (1)
- Deduktion (1)
- Deep Metric Learning (1)
- Defi-Now! (1)
- Defibrillator (1)
- Delta (1)
- Demographie (1)
- Demography (1)
- Densimetric Measurement (1)
- Depth Profile (1)
- Description Logic (1)
- Description Logics (1)
- Design Pattern (1)
- Destiny (1)
- Developer profiling (1)
- Diabetes (1)
- Diabetische Retinopathie (1)
- Diagnose (1)
- Diagnosekriterien (1)
- Diagnoseunterstützung (1)
- Diagnosis (1)
- Diagnosis assistance (1)
- Dichtemessung (1)
- Differentia Scanning Calorimetry (1)
- Differential scanning calorimetry (1)
- Diffuse Quellen (1)
- Diffusionsbildgebung (1)
- Digitale Bilder (1)
- Digitalisation (1)
- Digitalisierung (1)
- Dijkstras Algorithmus (1)
- Dimension 3 (1)
- Dimensionality Reduction (1)
- Dimensionsreduzierung (1)
- Discussion Forums (1)
- Diskrete Simulation (1)
- Distance Vector Routing (1)
- Distanz Vektor Routing (1)
- Distributed Algorithm (1)
- Distributed Environments (1)
- Distributed process execution (1)
- Documents (1)
- Dokumentation (1)
- Dracaena (1)
- Drahtloses Sensorsystem (1)
- Drahtloses lokales Netz (1)
- Drahtloses vermachtes Netz (1)
- Drainagegräben (1)
- Dredging (1)
- Dreidimensionale Bildverarbeitung (1)
- Driver Assistance Systems (1)
- Dynamische Analyse (1)
- Düngemittel (1)
- E-Business (1)
- E-Hyper Tableau (1)
- E-KRHyper theorem prover (1)
- E-Participation (1)
- E-Partizipation (1)
- E-government (1)
- E-participation (1)
- E-services (1)
- ECMS 2012 (1)
- ECSA (1)
- EU (1)
- East Africa (1)
- Ebener Graph (1)
- Ebullition (1)
- Eclipse <Programmierumgebung> (1)
- Economic potential (1)
- Ecosystem service (1)
- Ecotoxicity (1)
- Edelkrebs (1)
- Effectiveness (1)
- Einkauf (1)
- Einstellung (1)
- Einstellungen gegenüber bestimmten Filmeigenschaften (1)
- Ekel (1)
- Elastic net (1)
- Elektronenmikroskopie (1)
- Emergenz (1)
- Emissionen (1)
- Empfehlungssystem (1)
- Empirical Research (1)
- Empirical Studies (1)
- Emulation (1)
- Endangerment (1)
- Endokrine Regulation (1)
- Englisch (1)
- Enhanced Reality (1)
- Enhanced Representation (1)
- Enterprise Architecture Framework (1)
- Enterprise Information Management (1)
- Enterprise Systems (1)
- Entity Component System Architecture (1)
- Entrepreneurship Education (1)
- Entrepreneurship Experience and Extra-curricular Activity (1)
- Entscheidungsunterstützung (1)
- Entwickler Profil (1)
- Entwurfsmuster (1)
- Environmental Risk Assessment (1)
- Environmental factors (1)
- Environmental organic chemistry (1)
- Environmental samples (1)
- Epiphyten (1)
- Ergonomic Principles (1)
- Erste Hilfe (1)
- Erzieher (1)
- Erzieherin (1)
- European Conference on Modelling and Simulation (1)
- Europäischer Schadensbericht (1)
- Evacuation modeling (1)
- Evaluierung (1)
- Evidence-based Psychotherapy (1)
- Eye Tracking (1)
- Eyetracking (1)
- Fabric Simulation (1)
- Facebook Application (1)
- Facet Theory (1)
- Fahrverhalten (1)
- Fahrzeug (1)
- Farbkalibrierung (1)
- Farnpflanzen (1)
- Fast-slow continuum (1)
- Fault Trees (1)
- Feature Extraction (1)
- Feature Modeling (1)
- Fehlerbaum (1)
- Felis catus (1)
- Felis silvestris domestica (1)
- Ferns (1)
- Feuchtgebiet (1)
- Fiber Tracking (1)
- Filmbewertung (1)
- Fingerprint Recognition (1)
- First aid (1)
- Fischgewebe (1)
- Five Factor model (1)
- Fledermäuse (1)
- FlexViz (1)
- Fließgewässer (1)
- Flow decomposition (1)
- Fluid-Struktur Wechselwirkung (1)
- Fluss (1)
- Foliicolous lichens (1)
- Food (1)
- Food Transportation System (1)
- Foodstuff (1)
- Formal Methods (1)
- Formale Methoden (1)
- Fotoauswahl (1)
- Fractionation (1)
- Fragebeantwortung (1)
- Freeze Coring (1)
- Fremdsprachenunterricht (1)
- Function Words (1)
- Fungicides (1)
- Fungizid (1)
- Fuzzy-Logik (1)
- GDPR (1)
- GDS (1)
- GPGPU (1)
- GPS (1)
- GPU (1)
- GRAF1 (1)
- GReQL2 (1)
- GSM-Standard (1)
- Galerucinae (1)
- Gamification (1)
- Gammarus fossarum (1)
- Gangart (1)
- Ganzzahlige Optimierung (1)
- Gas storage capacity (1)
- Gasblasen (1)
- GazeTheWeb (1)
- Gefrierkernverfahren (1)
- Gefrierpunktserniedrigung (1)
- Gefährdung (1)
- Gefäßanalyse (1)
- Gefühl (1)
- Gehirn (1)
- Gel effect (1)
- Gelbbauchunke (1)
- Gelände (1)
- Gemischt-ganzzahlige Optimierung (1)
- Generative Model (1)
- Genetic diversity (1)
- Genetics (1)
- Genetik (1)
- Genetischer Fingerabdruck (1)
- Geocaching (1)
- Geographic routing (1)
- Geoinformationssystem (1)
- Geometric spanner (1)
- Geowissenschaften (1)
- Gerichteter Graph (1)
- Germany (1)
- Geschlecht (1)
- Gewässer (1)
- Gewässerqualität (1)
- Gewässerökologie (1)
- Glasumwandlung (1)
- Glasübergang (1)
- Globale Wertschöpfungsketten (1)
- Grafikkarte (1)
- Grafikprogrammierung (1)
- Grails (1)
- Grails 1.2 (1)
- Graph (1)
- Graph Technology (1)
- Graph theory (1)
- Graphentheorie (1)
- Graphicsprogramming (1)
- Graphik-Hardware (1)
- Graphische Benutzeroberfläche (1)
- Grundbedürfnis (1)
- Gruppenarbeit (1)
- Größenfraktionierung (1)
- Grünlandbewirtschaftung (1)
- Gut content analysis (1)
- Habitat loss (1)
- Habitat networks (1)
- Habitatfragmentierung (1)
- Habitatsverlust (1)
- Hand-based Gestures (1)
- Handsfree editing (1)
- Hard and Soft News (1)
- Haskell (1)
- Hauskatze (1)
- Health (1)
- Healthcare institution (1)
- Hedonic (1)
- Hedonisch (1)
- Herbizid (1)
- Herzrate (1)
- Hindernis (1)
- Horn Clauses (1)
- Human Disturbance (1)
- Human motion (1)
- Human resources management (1)
- Human-Computer Interaction (1)
- Humus (1)
- Hyaluronan (1)
- Hyaluronsäure (1)
- Hydratation (1)
- Hydration (1)
- Hydrodynamik (1)
- Hydrogel (1)
- Hydrophobie (1)
- Hyper Tableau Calculus (1)
- Hypertableaux (1)
- I-messages (1)
- IASON (1)
- IAT (1)
- IBM Bluemix (1)
- ICM (1)
- ICP-MS (1)
- IPT (1)
- IT Guru (1)
- IT Outsourcing (1)
- IT Security (1)
- IT Services (1)
- IT-Security (1)
- IceCube (1)
- Image (1)
- Image Processing (1)
- Image Understanding (1)
- Implicit Association Test (1)
- Incremental Algorithms (1)
- Industrial-CT (1)
- Industriepolitik (1)
- Informatik (1)
- Information Asset Register (1)
- Information Audit (1)
- Information Capturing Methods (1)
- Information Centric Networking (1)
- Information Retrieval (1)
- Information system (1)
- Inkompressible Fluide (1)
- Innerbetriebliche Kooperation (1)
- Inpainting-Verfahren (1)
- Insecticide (1)
- Instructed Second Language Acquisition (1)
- Insurance (1)
- Integrated Model (1)
- Intelligent Information Network (1)
- Interactive Video Retrieval (1)
- Interaktion (1)
- Interaktionseffekt (1)
- Intergruppenprozesse (1)
- International organization (1)
- Internationale Organisationen (1)
- Internet (1)
- Internet Voting (1)
- Interoperability (1)
- Interoperabilität (1)
- Interparticulate hydrogel swelling (1)
- IoT (1)
- JGraLab (1)
- JML (1)
- Java (1)
- Java <Programmiersprache> (1)
- Java Modeling Language (1)
- Java. Programmiersprache (1)
- Journalismusforschung (1)
- Justification (1)
- KRHyper (1)
- Kalkmagerrasen (1)
- Kanalcodierung (1)
- Kantenbewerteter Graph (1)
- Kantenverfolgung (1)
- Katastrophentheorie (1)
- Kation-Brücken (1)
- Kationen (1)
- Katze (1)
- Kenya (1)
- Klassifikation (1)
- Klima (1)
- Klimawandel (1)
- Knowledge (1)
- Knowledge Engineering (1)
- Knowledge Graphs (1)
- Knowledge Sharing (1)
- Kognitive Entwicklung (1)
- Kohlenstoffschichten (1)
- Kollaboration (1)
- Kollektivismus (1)
- Kolloid (1)
- Kolloide (1)
- Kolloids (1)
- Komplexität / Algorithmus (1)
- Konjugation (1)
- Konkurrenz (1)
- Konsistenz. Psychologie (1)
- Konsumentenverhalten (1)
- Kontaktwinkel (1)
- Konturfindung (1)
- Konzept (1)
- Krebspest (1)
- Kriterium (1)
- Kryo (1)
- Körperliche Aktivität (1)
- Künstliche Intelligenz (1)
- Künstliche Neuronale Netze (1)
- Lake Kinneret (1)
- Lake Naivasha (1)
- Lake Wamala (1)
- Landscape ecology (1)
- Landschaftskartierung (1)
- Landschaftsökologie (1)
- Langlebigkeit (1)
- Laser (1)
- Lasso (1)
- Last-year students (1)
- Latent Negative (1)
- Laufen (1)
- Lebenslanges Lernen (1)
- Lebensmittel (1)
- Lebensstandard (1)
- Lehrerbildung (1)
- Lehrerkompetenzen (1)
- Leugnung (1)
- Life history (1)
- Limology (1)
- Linespace (1)
- Link Prediction (1)
- Linked Data Modeling (1)
- Loans (1)
- Local algorithm (1)
- Logik (1)
- Logischer Schluss (1)
- Lokalisation (1)
- Longevity (1)
- Lurche (1)
- Lycophytes (1)
- MIA (1)
- MPEG-7 (1)
- MSR (1)
- Machine-Learning (1)
- Machinelles lernen (1)
- Magnetis (1)
- Maifisch (1)
- Makrophyten (1)
- MapReduce (1)
- Mapping <Mathematics> (1)
- Maschinelles Sehen (1)
- Mass-Spektrometrie (1)
- Matching (1)
- Material Point Method (1)
- Mathematical optimisation (1)
- Mathematik (1)
- Maßtheorie (1)
- MeVisLab (1)
- Measure-theory (1)
- Mediator framework (1)
- Medical Image Analysis (1)
- Medizinische Bildanalyse (1)
- Medizinische Bildverarbeitung (1)
- Meiofauna (1)
- Mensch-Maschine-Interaktion (1)
- Merkmalsdetektion (1)
- Merkmalsextrahierung (1)
- Mesofauna (1)
- Metalle/Matalloide (1)
- Metalloids (1)
- Metals (1)
- Metals/metalloids (1)
- Metapher (1)
- Metapopulation dynamics (1)
- Metapopulationsdynamiken (1)
- Methan (1)
- Methane emissions (1)
- Methode (1)
- Microfinance (1)
- Microfinance institutions (1)
- Micropollutants (1)
- Migration (1)
- Mikrofinanzierung (1)
- Mikroorganismus (1)
- Mikrosatelliten-DNA (1)
- Mikroverunreinigung (1)
- Minderung (1)
- Minimalschnitt (1)
- Mining (1)
- Mining Software Repositories (1)
- Mister X (1)
- Mitral Valve (1)
- Mitralklappe (1)
- Mixed integer programming (1)
- Mixed method (1)
- Mixed methods (1)
- Mixture Toxicity (1)
- Mobile Information Systems (1)
- Model-Driven Engineering (1)
- Modellfahrzeug (1)
- Monitoring (1)
- Monolepta (1)
- Morphologische Operatoren (1)
- Mosambik (1)
- Motion Capturing (1)
- Motivation (1)
- Mouse Gestures (1)
- Movie evaluation criteria (1)
- Mucilage (1)
- Multi-Agenten-Systeme (1)
- Multi-robot System (1)
- Multiagent System (1)
- Multiagentensysteme (1)
- Multidimensional (1)
- Multimedia Metadata Ontology (1)
- Multimodal Medical Image Analysis Cochlea Spine Non-rigid Registration Segmentation ITK VTK 3D Slicer CT MRI CBCT (1)
- Multiple Object Tracking (1)
- Multivariable Statistik (1)
- N-Body Simulation (1)
- N-Körper Simulation (1)
- NMR relaxometry (1)
- NMR-Spektroskopie (1)
- Nachbarschaftsgraph (1)
- Nachtfalter (1)
- Nachtschmetterlinge (1)
- Named Function Networking (1)
- Nanoröhren (1)
- Nassbaggerung (1)
- Nationalismus (1)
- Native language identification (1)
- Natural Feature Tracking (1)
- Natural Language Processing (1)
- Naturschutzgenetik (1)
- Naturschutzmanagement (1)
- Natürliche Schädlingskontrolle (1)
- Natürliches organisches Material (1)
- Navier-Stokes Gleichungen (1)
- Navier-Stokes equations (1)
- Network robustness (1)
- Networks (1)
- Netzwerk Routing (1)
- Netzwerkanalyse (1)
- Netzwerkrobustheit (1)
- Netzwerktopologie (1)
- Neuroactive chemicals (1)
- Neuronales Netz (1)
- Neutino (1)
- Nicht-Ziel-Pflanzen (1)
- Non-freezing water (1)
- Nuclear Magnetic R (1)
- Nutzererleben (1)
- Nährstoffverfügbarkeit (1)
- Nützlinge (1)
- OCB (1)
- OCL <Programmiersprache> (1)
- ODRL (1)
- ONDEX (1)
- OPD-SHRM (1)
- OPNET (1)
- OVTK (1)
- Oberflächen-Runoff (1)
- Oberflächeneigenschaft (1)
- Oberflächenveredelung (1)
- Object Recognition (1)
- Objektentfernung (1)
- Oligomer (1)
- Online Community (1)
- Online grocery shopping (1)
- Online-Lebensmittelhandel (1)
- Ontologie. Wissensverarbeitung (1)
- Ontology API model (1)
- Ontology alignment (1)
- Open Content (1)
- Open Source (1)
- OpenGL Shading Language (1)
- Optimierung (1)
- Optimization (1)
- Oracle Generation (1)
- Oraklegenerierung (1)
- Organische Bodensubstanz (1)
- Organizational Change (1)
- Oriental region (1)
- Ostafrika (1)
- Osteocephalus (1)
- Ozon (1)
- Ozonisierung (1)
- PEPPOL (1)
- POIs (1)
- Pan European Public Procurement OnLine (1)
- Parteienkommunikation (1)
- Passiver Wortschatz (1)
- Path Tracing (1)
- Pattern Recognition (1)
- Perfect (1)
- Perfekt (1)
- Personalised Information Systems (1)
- Personality (1)
- Persönlichkeit (1)
- Pestizide (1)
- Petri net (1)
- Petri-Netz (1)
- Petrinetz (1)
- Pfadnachverfolgung (1)
- Pfadplanung (1)
- Pfadverfolgung (1)
- Pflanzen (1)
- Pharmaceuticals (1)
- Pharmakokinetik (1)
- Phosphorsäureester (1)
- Photographie (1)
- Phylogeographie (1)
- Physik (1)
- Physiksimulation (1)
- Placement Strategies (1)
- Planar graphs (1)
- Plant Communities (1)
- Plant protection products (1)
- Plasticization; Glass transition (1)
- Plastifizieren (1)
- Plastifizierung (1)
- Plug in (1)
- Pointing Devices (1)
- Policy Language (1)
- Political Communication (1)
- Politik (1)
- Politische Ökonomie (1)
- Pollinators (1)
- Pollution (1)
- Polysaccharide (1)
- Polysaccharides (1)
- Populationsgenetik (1)
- Pore Water (1)
- Pragmatic (1)
- Pragmatisch (1)
- Predictive Model (1)
- Present Perfect (1)
- Proactive Caching (1)
- Probabilistic finite automata (1)
- Probability (1)
- Probability propagation nets (1)
- Proceedings (1)
- Process (1)
- Process Quality (1)
- Process tracing (1)
- Product choice (1)
- Produktbewertung (1)
- Produktentscheidung (1)
- Produktwahl (1)
- Programmierung (1)
- Prosoziales Verhalten (1)
- Proteinstrukturanalyse (1)
- Provenance (1)
- Prozedurale Synthese (1)
- Prozessqualität (1)
- Prädikatenlogik (1)
- Präposition (1)
- Präsentisches Perfekt (1)
- Pteris (1)
- Pyrethroide (1)
- Pädagogik (1)
- Quality assessment system (1)
- Quasi unit disk graph (1)
- Query Expansion (1)
- RDF Graphs (1)
- RDF modeling (1)
- Railway Research (1)
- Railway Research Topics (1)
- Railway Safety (1)
- Railway Safety Research (1)
- Random Finite Sets (1)
- Random Forest (1)
- Raupe (1)
- Raytracing (1)
- ReDSeeDS-Project (1)
- Reactive algorithm (1)
- Real-Life Game (1)
- Real-Life Spiel (1)
- Rechtfertigung (1)
- Rechtfertigung <Philosophie> (1)
- Recommender System (1)
- Recommender Systems, Business Process Modeling, Literature Review (1)
- Recovery (1)
- Reddit (1)
- Reengineering (1)
- Reference Model (1)
- Referenzrahmen (1)
- Reflections (1)
- Reflektionen (1)
- Regenwald (1)
- Regenwald ; Afrika ; Cheilolejeunea (1)
- Regionenlabeling (1)
- Registratur (1)
- Rehabilitation (1)
- Relevance Feedback (1)
- Religiosität (1)
- Rendering (1)
- Renewable energy (1)
- Reproduktion (1)
- Reservoir Sedimentation (1)
- Resource Description Framework (RDF) (1)
- Resource Governance (1)
- Retina Befundbilder (1)
- Retina Fundus Bilder (1)
- Retina Fundus Images (1)
- Reverse Engineering (1)
- Revision (1)
- Rezeptionsforschung (1)
- Rhein (1)
- Rheinland-Pfalz (1)
- Rheometry (1)
- Rhineland-Palatinate (1)
- Rhizosphere (1)
- Right-wing ideology (1)
- Risikoabschätzung (1)
- Risikominimierung (1)
- Risk assessment (1)
- RoboCup (1)
- Robocup 2008 (1)
- Roboter (1)
- Robotik (1)
- Robust Principal Component Analysis (1)
- Rothe's method (1)
- Rothe-Methode (1)
- Routing (1)
- Routing Information Protocol (1)
- Routing Information Protocol (RIP) (1)
- Routing Information Protokoll (1)
- Routing Loops (1)
- Routing with Metric based Topology Investigation (RMTI) (1)
- Ruscaceae (1)
- Russia (1)
- Räuber (1)
- Rückverfolgbarkeit (1)
- SOA (1)
- SPARQL (1)
- SPEAR (1)
- STOF Model (1)
- Salinisation (1)
- Sand (1)
- Satelliten-DNS (1)
- Sattelkraftfahrzeug (1)
- Sattelzug (1)
- Saving (1)
- Saving and credit cooperatives (SACCOs) (1)
- Schadstoffbelastung (1)
- Schadstoffkonzentration (1)
- Schema Information (1)
- Schizophrenie (1)
- Schnee (1)
- Schreiben (1)
- Schreibtechnik (1)
- Schulden (1)
- Schwache Lösungen (1)
- Schwebstoffe (1)
- Schwermetalle (1)
- Schädlingskontrolle (1)
- Search engine (1)
- Security (1)
- Security Requirements (1)
- Security Routing (1)
- Sediment Water Interface (1)
- Sediment-Water-Interfaces (1)
- Segmentation (1)
- Segmentierung (1)
- Selbstbeobachtung (1)
- Selbstbeschädigung (1)
- Selbsteinschaetzung (1)
- Selbstorganisation (1)
- Selbstregulation (1)
- Self-determination theory (1)
- Semantic Data (1)
- Semantic Web Data (1)
- Semantics (1)
- Sensing as a Service (1)
- Service identification (1)
- Service-Identifizierung (1)
- Service-oriented Architectures (SOA) (1)
- Service-orientierte Architektur (1)
- Sexuelle Orientierung (1)
- Shader (1)
- Sicherheit Routing (1)
- Simulationswerkzeug (1)
- Size-fractionation (1)
- Skalenkonstruktion (1)
- Skalenvalidierung (1)
- Skalierungsmodelle (1)
- Smartphone (1)
- Smartphone Applikation (1)
- Social Cognitive Career Theory (1)
- Social Entrepreneurship in Vietnam (1)
- Social Games (1)
- Social Networking Platforms (1)
- Social identity theory (1)
- Socio-economic development (1)
- Software (1)
- Software Development (1)
- Software Language (1)
- Software Repositories (1)
- Software Technology (1)
- Software migration (1)
- Software techniques for object recognition (STOR) (1)
- Software-Migration (1)
- Softwarearchitektur (1)
- Softwareentwicklung (1)
- Softwareergonomie (1)
- Softwaretesting (1)
- Softwarewartung (1)
- Soil physics (1)
- Soil structural stability (1)
- Solutions (1)
- Sorption (1)
- Southern Amazonia (1)
- Soziale Identität (1)
- Soziale Wahrnehmung (1)
- Soziales Netzwerk (1)
- Soziales System (1)
- Sozialwissenschaftliche Simulation (1)
- Sparen (1)
- Speaker Recognition (1)
- Spear (1)
- Speciation (1)
- Species turnover (1)
- Specification (1)
- Specular (1)
- Spezifikation (1)
- Sprechweise (1)
- Standard of living (1)
- Statistical Shape Model (1)
- Staubewässerung (1)
- Staugeregelte Flüsse (1)
- Stauseeverlandung (1)
- Stechmücke (1)
- Stechmücken-Kontrolle (1)
- Stereotyp (1)
- Stereotype Content Model (1)
- Steuerung (1)
- Stimme (1)
- Stimmungsveränderung (1)
- Stochastic Logic (1)
- Stoffsimulation (1)
- Strassenkreuzung (1)
- Straßenzustand (1)
- Streams (1)
- Structural Equation Modeling (1)
- Structural Validity (1)
- Strukturelle Validität (1)
- Support System (1)
- Survey Research (1)
- Sustainability (1)
- Systematics (1)
- Systembiologie (1)
- Säugetiere (1)
- Südafrika (1)
- Süßwasserhaushalt (1)
- TAP (1)
- TBox (1)
- TRECVID (1)
- Tableau Calculus (1)
- Technical potential (1)
- Technologischer Raum (1)
- Tempus (1)
- Tenneco Automotive (1)
- Tense (1)
- Test Generation (1)
- Testen (1)
- Testgenerierung (1)
- Text (1)
- Text Analysis (1)
- Text Mining (1)
- Text classification (1)
- Texterkennung (1)
- Theorem prover (1)
- Theorembeweiser (1)
- Time (1)
- Titandioxid-Nanopartikeln (1)
- Tokens (1)
- Tool Evaluation (1)
- Torf (1)
- Toxicological characterization (1)
- Toxicology (1)
- Toxikologische Bewertung (1)
- Toxizität (1)
- Traceability (1)
- Tracing (1)
- Tracking-System (1)
- Transferfunction (1)
- Transferfunktion (1)
- Transformation products (1)
- Transformationsprodukte (1)
- Transport (1)
- Tropfenform (1)
- Tropical rainforest (1)
- Tropischer Regenwald (1)
- Type System (1)
- Type system (1)
- Ubuntu (1)
- Ultraschall (1)
- Ultrasound (1)
- Umfrage in Koblenz (1)
- Umkehrosmose (1)
- Umwelt (1)
- Umweltchemikalie (1)
- Umweltproben (1)
- Umweltverschmutzung (1)
- Unified Modeling Language (UML ) (1)
- Unit disk graph (1)
- Unlink Prediction (1)
- Unsicheres Schließen (1)
- Unterrichtsforschung (1)
- Unterrichtsqualität (1)
- Untersuchung (1)
- Unterwasser-Pipeline (1)
- Unterwasserfahrzeug (1)
- Unterwasserkabel (1)
- Unterwasserwelt (1)
- User experience (1)
- User-Needs Analysis (1)
- VCD (1)
- VIACOBI (1)
- Variabilität (1)
- Vascular analysis (1)
- Vegetation (1)
- Vegetation distribution (1)
- Verb (1)
- Verbal Aspect (1)
- Verbraucherverhalten (1)
- Vergangenheitstempus (1)
- Verhandlung (1)
- Verification (1)
- Verifikation (1)
- Vermeidung (1)
- Versalzung (1)
- Verteilter Algorithmus (1)
- Verteilung (1)
- Virtual Company Dossier (1)
- Virtual characters (1)
- Virtuelle Realität (1)
- Visibility Skeleton (1)
- Visual Stimuli Discovery (1)
- Visualisierung von Verbformen (1)
- Vocabulary (1)
- Vocabulary Mapping (1)
- Vocabulary Reuse (1)
- Vocabulary Trainer (1)
- Vokabellernen (1)
- Volume Hatching (1)
- Vorschulkind (1)
- Vulnerability (1)
- WCET (1)
- WEB (1)
- WLAN Fingerprinting (1)
- WSDL (1)
- WSN (1)
- Wachstumsregler (1)
- Wahlen zum europäischen Parlament (EU-Wahlen) (1)
- Wahrscheinlichkeit (1)
- Wahrscheinlichkeitsrechnung (1)
- Wanderfische (1)
- Wasser-Sediment-Grenzschichten (1)
- Wasserverschmutzung (1)
- Wastewater (1)
- Water Management (1)
- Water quality (1)
- Wavelet (1)
- Wearables (1)
- Web (1)
- Web Analytics (1)
- Web Analytics Framework (1)
- Web Mining (1)
- Web Ontology Language (OWL) (1)
- Web Science (1)
- Web Services (1)
- Web log (1)
- Web-application framework (1)
- Web-programming technologies (1)
- Weblog (1)
- Website (1)
- Wechselkursänderung (1)
- Weinbau (1)
- Weltkultur (1)
- Werbung (1)
- WiFi Fingerprinting (1)
- Wiederbesiedlung (1)
- Wild pollinator (1)
- Wildbienen (1)
- Wildtiere (1)
- Wireless sensor network (1)
- Wirtschaft (1)
- Wirtschaftsenglisch (1)
- Wissensbasis (1)
- Wissensmanagement (1)
- Word-of-Mouth (1)
- World Wide Web 2.0 (1)
- Wortschatz (1)
- Wrapping (1)
- Yellow-bellied toad (1)
- You-messages (1)
- Zeit (1)
- Zikaden (1)
- Zoologie (1)
- Zoology (1)
- Zooplankton (1)
- Zuckmücken (1)
- Zusammenhängender Graph (1)
- absolutism (1)
- acceptance (1)
- activated sludge (1)
- adaptive GUI Design (1)
- adaptive resonance theory (1)
- adjoint functions (1)
- advanced wastewater treatment (1)
- agent-based simulation (1)
- agroecosystems (1)
- amorphous hydrogenated carbon layer (1)
- amphibians (1)
- analytics (1)
- anthropogenic disturbance (1)
- application programming interfaces (1)
- aquatic environment (1)
- aquatic invertebrates (1)
- archiving (1)
- artifcial neural networks (1)
- artiffficial neural networks (1)
- artififfcial neural networks (1)
- assessment model (1)
- attitudes towards specific movie features (1)
- authoritarianism (1)
- automated theorem prover (1)
- automatic behavioral cues (1)
- backpropagation (1)
- bait-lamina test (1)
- bats (1)
- behavior change (1)
- behavioural ecology (1)
- belief in just world (1)
- beneficial insects (1)
- benefits (1)
- benthic oxygen fluxes (1)
- bias (1)
- biocide (1)
- biocides (1)
- biodegradation (1)
- biodiversity (1)
- biofiltration (1)
- bioindicator (1)
- biological degradation (1)
- biologischer Abbau (1)
- biotransformation (1)
- bioturbation (1)
- blockchain (1)
- blood analysis (1)
- bribery (1)
- business intelligence (1)
- business process management (1)
- by-stander effect (1)
- carbon hybridisation (1)
- catastrophy theory (1)
- categorisation (1)
- cation bridges (1)
- cation-bridges (CaB) (1)
- chalk grassland (1)
- change (1)
- chaos (1)
- chemical force microscopy (1)
- chemical risk assessment (1)
- chironomids (1)
- clonal diversity (1)
- cognitive development (1)
- cognitive linguistic approach (1)
- collaboration (1)
- collaborative technologies (1)
- collectivism (1)
- colloid (1)
- colour calibration (1)
- competence- and control beliefs (1)
- competition (1)
- concept (1)
- concurrency (1)
- conflict detection (1)
- conservation genetics (1)
- construction materials (1)
- contact angle (1)
- contexts of use (1)
- cooperation (1)
- core ontologies (1)
- core self-evaluations (1)
- corrosion protection (1)
- covid-19 (1)
- criminal victimization (1)
- critical section (1)
- crop pollination (1)
- cross-cultural psychology (1)
- cross-linking (1)
- cryo-electron microscopy (1)
- cultural dimensions (1)
- cultural landscape (1)
- currency exchange rates (1)
- data (1)
- data mining (1)
- data protection (1)
- data sharing (1)
- data warehouse (1)
- decision support tool (1)
- deductive (1)
- delivery drone (1)
- dengue (1)
- density separation (1)
- design thinking (1)
- deutsche Hochschulen (1)
- diabetic retinopathy (1)
- diffusion (1)
- diffusion (1)
- digestion (1)
- digital transformation (1)
- directed acyclic graphs (1)
- disgust sensitivity (1)
- distinct object identifiers (1)
- distributed information systems (1)
- distributed ledger (1)
- distribution (1)
- disturbance (1)
- drone (1)
- e-Commerce (1)
- e-learning (1)
- e-service (1)
- e-service quality (1)
- eGovernment (1)
- eSourcing (1)
- eXperience methodology (1)
- ebullition (1)
- ecological risk management (1)
- ecology (1)
- ecosystem functioning (1)
- ecosystem functions (1)
- ecosystem services (1)
- eddy correlation (1)
- edge linking (1)
- effect assessment (1)
- effect-directed analysis (1)
- emergence (1)
- emerging micropollutants (1)
- endocrine disrupting chemicals (1)
- endokrine Regulation (1)
- energetics (1)
- engineered nanoparticles (1)
- english prepositions (1)
- enterprise collaboration platforms (1)
- enterprise collaboration systems (1)
- entrepreneurial design thinking (1)
- entrepreneurial thinking (1)
- entrepreneurship education (1)
- environmental compatibility (1)
- environmental control (displays of self, control of stress factors, social control), well-being, work or learning efficiency, social behavior, co mmunication (1)
- environmental fate (1)
- environmental psychology (1)
- environmental risk assessment (1)
- environmental surfaces (1)
- epidemiology (1)
- epoxide (1)
- erweiterte Abwasserbehandlung (1)
- estimation of algorithm efficiency (1)
- evaluation (1)
- event model (1)
- event-based systems (1)
- events (1)
- evolution (1)
- expansion (1)
- faceted search (1)
- fairness (1)
- field experiment (1)
- field margin (1)
- finite state automata (1)
- first-order logic (1)
- fish tissues (1)
- floral resources (1)
- flows over time (1)
- fluid disturbances (1)
- fluid-structure interaction (1)
- focused feedback (1)
- folksonomies (1)
- freshwater ecosystem (1)
- functional web testing tools (1)
- fungicide (1)
- fungus resistant grapevine (1)
- futex (1)
- gait (1)
- galvanic anodes (1)
- gaze information (1)
- gender (1)
- genotyping error (1)
- giftedness (1)
- glass transition (1)
- grade (1)
- gradient method of training weight coefficients (1)
- grassland (1)
- grassland irrigation (1)
- greenhouse gases (1)
- groundwater remediation (1)
- groupwork (1)
- hazard prediction (1)
- healthcare (1)
- heart rate (1)
- humic acid (1)
- hybrid systems (1)
- hybride Automaten (1)
- hydrodynamic chromatography (1)
- hydrodynamische Chromatographie (1)
- hydrophobicity (1)
- hypertableaux (1)
- iCity project (1)
- image processing (1)
- image semantics (1)
- image warping (1)
- immediate priority ceiling protocol (1)
- implicit-explicit consistency (1)
- impounded rivers (1)
- in situ (1)
- incompressible fluids (1)
- information infrastructure (1)
- information retrieval (1)
- information system (1)
- insecticide (1)
- interaction (1)
- intergroup contact (1)
- internet of things (1)
- invasive Arten (1)
- invasive species (1)
- iot development platforms (1)
- jOWL (1)
- kinematics (1)
- klonale Diversität (1)
- knowledge base (1)
- knowledge management system (1)
- knowledge work (1)
- land use (1)
- land use change (1)
- landmarks (1)
- landscape (1)
- landscape complexity (1)
- landscape mapping (1)
- laser induced fluorescence (1)
- leaching (1)
- lead desorption (1)
- leaf beetles (1)
- leafhoppers (1)
- leap motion (1)
- life cycle test (1)
- lifelong learning (1)
- living book (1)
- logistic (1)
- long-living systems (1)
- longitudinal (1)
- mPayments (1)
- machine learning (1)
- macroinvertebrates (1)
- mammals (1)
- mathematical Modelling (1)
- mathematical model (1)
- mathematische Modellbildung (1)
- measure (1)
- media competence model (1)
- medical care (1)
- medical image processing (1)
- metadata formats (1)
- metadata standards (1)
- metal-film phase plate (1)
- methane (1)
- methodology (1)
- micro-agent (1)
- microorganisms (1)
- microsatellite DNA (1)
- microsatellite analysis (1)
- minimal pruning (1)
- minimum self-contained graphs (1)
- mitigation (1)
- mitigation measures (1)
- mixtures (1)
- mobile application (1)
- mobile devices (1)
- mobile facets (1)
- mobile health care (1)
- mobile interaction (1)
- model generation (1)
- model-driven engineering (1)
- modeling (1)
- modulares System (1)
- monitor (1)
- mood change (1)
- morphological operators (1)
- multiagent systems (1)
- multidimensional (1)
- mutual exclusion (1)
- nanoparticle (1)
- nationalism (1)
- natural organic matter (1)
- nature conservation (1)
- negotiation (1)
- networks (1)
- neuartige Spurenstoffe (1)
- neural (1)
- nicht gefrierbares Wasser (1)
- nichtlinearer Zusammenhang (1)
- nichtsuizidale Selbstverletzung (1)
- non-consumptive effects (1)
- non-point source (1)
- non-target effects (1)
- non-target plants (1)
- norm (1)
- nternational organizations (1)
- numerical simulation (1)
- off-field habitats (1)
- olive mill wastewater (1)
- optimization (1)
- organic coatings (1)
- organic pollution (1)
- organizational behavior (1)
- organophosphate (1)
- ozonation (1)
- ozonation of beta blockers (1)
- ozone (1)
- ozone reactivity (1)
- pH-Wert (1)
- parallel calculations (1)
- parameter estimation (1)
- path planning (1)
- peat (1)
- pelzresistente Rebsorten (1)
- performance optimization (1)
- periphyton (1)
- personal information management (1)
- persönliches Informationsmanagement (1)
- pest control (1)
- pesticide risk assessment (1)
- pharmaceuticals (1)
- phenolic compounds (1)
- photo selection (1)
- physical activity (1)
- plant protection products (1)
- planthoppers (1)
- plants (1)
- plastic consumption (1)
- plastic debris (1)
- playful learning (1)
- point source (1)
- points of interest (1)
- policy modelling (1)
- pollen diet (1)
- pollinator development (1)
- pollinator fitness (1)
- pollution (1)
- polyurethane (1)
- population genetics (1)
- predation (1)
- predictability (1)
- preschool children (1)
- priority effects (1)
- priority-Effekte (1)
- privacy and personal data (1)
- privacy by design (1)
- privacy competence model (1)
- privacy impact assessment (1)
- privacy protection (1)
- probabilistic (1)
- procedural content generation (1)
- prosocial behavior (1)
- prosoziale Gruppennorm (1)
- public key infrastructure (1)
- punishment goals (1)
- pyrethroids (1)
- question answering (1)
- rainforest (1)
- reasoning (1)
- recolonisation (1)
- recurrent (1)
- region labeling (1)
- regression analysis (1)
- regular dag languages (1)
- regulation (1)
- relative Prototypikalität (1)
- religiousness (1)
- repellency (1)
- reproduction (1)
- requirements analysis (1)
- retina fundus images (1)
- reverse osmosis (1)
- revision (1)
- rich multimedia presentations (1)
- risks (1)
- robotics (1)
- rocking-phase plate (1)
- running (1)
- runoff (1)
- sample pretreatment (1)
- scale construction (1)
- scale validation (1)
- scene analysis (1)
- school attack (1)
- school tier (1)
- science learning (1)
- security (1)
- security awareness (1)
- self-concept (1)
- self-efficacy (1)
- self-organisation (1)
- semantic annotation (1)
- semantic desktop (1)
- semantischer Desktop (1)
- sequent calculi (1)
- sexual orientation (1)
- shiq (1)
- silver nanoparticles (1)
- single-particle analysis (1)
- smartphone app (1)
- social media data (1)
- social object (1)
- social perception (1)
- social system (1)
- software engineering (1)
- soil (1)
- soil aquifer treatment (1)
- soil pH (1)
- soil solution (1)
- soils (1)
- sparsity (1)
- spatial Fuzzy Logic (1)
- spatial and temporal varibility (1)
- speech (1)
- spray-drift (1)
- stereoscopic rendering (1)
- stereotypes (1)
- stream (1)
- stream mesocosm (1)
- student misbehavior (1)
- summative evaluation (1)
- surface characteristics (1)
- survey in Koblenz (1)
- suspended particle matter (1)
- swarming (1)
- swimming behaviour (1)
- systematics (1)
- systems to judge the quality of buildings (1)
- tag recommendation (1)
- tagging (1)
- task orientation (1)
- teacher beliefs (1)
- teacher education (1)
- teacher motivation (1)
- teacher training (1)
- teaching (1)
- teams (1)
- technology acceptance model (1)
- text-picture integration (1)
- thermal analysis (1)
- time series (1)
- tool-integration (1)
- toxicokinetics (1)
- trace organic chemicals (1)
- traceability (1)
- trait-mediated effects (1)
- transformation products (1)
- transport (1)
- trophic cascades (1)
- unique name assumption (1)
- uptake (1)
- usability study (1)
- variational discretization (1)
- vascular plants (1)
- vaskuläre Planzen (1)
- vegetated treatment systems (1)
- vegetation modeling (1)
- verification (1)
- video games (1)
- virtual goods (1)
- viticulture (1)
- voice (1)
- volume rendering (1)
- warp divergence (1)
- wastewater treatment plant (1)
- water pollution (1)
- water re-use (1)
- water reuse (1)
- water scarcity (1)
- water treatment (1)
- water-molecule-bridges (WaMB) (1)
- weak solution (1)
- web 2.0 (1)
- web-portal medical e-services (1)
- wettability (1)
- wild bees (1)
- wildlife management (1)
- window of opportunity (1)
- wireless sensor networks (1)
- world polity (1)
- writing (1)
- zooplankton (1)
- Ästuar (1)
- Ökologie (1)
- Ökotoxologie (1)
- Überarbeitung (1)
- Überwachung (1)
Institute
- Fachbereich 4 (112)
- Institut für Informatik (78)
- Fachbereich 7 (72)
- Institut für Wirtschafts- und Verwaltungsinformatik (51)
- Institute for Web Science and Technologies (49)
- Institut für Computervisualistik (48)
- Institut für Integrierte Naturwissenschaften, Abt. Biologie (21)
- Fachbereich 8 (20)
- Institut für Management (20)
- Institut für Umweltwissenschaften (19)
Today’s agriculture heavily relies on pesticides to manage diverse pests and maximise crop yields. Despite elaborate regulation of pesticide use based on a complex environmental risk assessment (ERA) scheme, the widespread use of these biologically active compounds has been shown to be a threat to the environment. For surface waters, pesticide exposure has been observed to exceed safe concentration levels and negatively impact stream ecology leading to the question whether current ERA schemes ensure a sustainable use of pesticides. To answer this, the large-scale “Kleingewässer-Monitoring” (KgM) assessed the occurrence of pesticides and related effects in 124 streams throughout Germany, Central Europe, in 2018 and 2019.
Based on five scientific publications originating from the KgM, this thesis evaluated pesticide exposure in streams, ecological effects and the regulatory implications. More than 1,000 water samples were analysed for over 100 pesticide analytes to characterise occurrence patterns (publication 1). Measured concentrations and effects were used to validate the exposure and effect concentrations predicted in the ERA (publication 2). By jointly analysing real-world pesticide application data and measured pesticide mixtures in streams, the disregard of environmental pesticide mixtures in the ERA was evaluated (publication 3). The toxic potential of mixtures in stream water was additionally investigated using suspect screening for 395 chemicals and a battery of in-vitro bioassays (publication 4). Finally, the results from the KgM stream monitoring were used to assess the capability to identify pesticide risks in governmental monitoring programmes (publication 5).
The results of this thesis reveal the widespread occurrence of pesticides in non-target stream ecosystems. The water samples contained a variety of pesticides occurring in complex mixtures predominantly in short-term peaks after rainfall events (publications 1 & 4). Respective pesticide concentration maxima were linked to declines in vulnerable invertebrate species and exceeded regulatory acceptable concentrations in about 80% of agricultural streams, while these thresholds were still estimated partly insufficient to protect the invertebrate community (publication 2). The co-occurrence of pesticides in streams led to a risk underestimated in the single substance-oriented ERA by a factor of about 3.2 in realistic worst-case scenarios, which is further exacerbated by a high frequency at which non-target organism are exposed to pesticides (publication 3). Stream water samples taken after rainfall caused distinct effects in bioassays which were only explainable to a minor extent by the many analytes, indicating the relevance of unknown chemical or biological mixture components (publication 4). Finally, the regulatory monitoring of surface waters under the Water Framework Directive (WFD) was found to significantly underestimate pesticide risks, as about three quarters of critical pesticides and more than half of streams at risk were overlooked (publication 5).
Essentially, this thesis involves a new level of validation of the ERA of pesticides in aquatic ecosystems by assessing pesticide occurrence and environmental impacts at a scale so far unique. The overall results demonstrate that the current agricultural use of pesticides leads to significant impacts on stream ecology that go beyond the level tolerated under the ERA. This thesis identified the underestimation of pesticide exposure, the potential insufficiency of regulatory thresholds and the general inertia of the authorisation process as the main causes why the ERA fails to meet its objectives. To achieve a sustainable use of pesticides, the thesis proposes substantial refinements of the ERA. Adequate monitoring programmes such as the KgM, which go beyond current government monitoring efforts, will continue to be needed to keep pesticide regulators constantly informed of the validity of their prospective ERA, which will always be subject to uncertainty.
Harvesting Season?
(2022)
Efforts to induce customers to buy groceries through the Internet have existed for around twenty years. Early on, the market structures of the digital grocery trade were still strongly fragmented and poorly coordinated. Due to the technological advancement in the past decade, the digital purchase of groceries has become more attractive. The adoption rate of these services varies greatly between different regions. In Germany in particular, the digital grocery trade is stagnating at a comparatively low level. In this regard, this dissertation analyzes both the retail-side market structures and the expectations and obstacles of German consumers.
The year 2020 connotes a turning point for the online grocery trade, as daily routines such as grocery shopping were subject to strict regulations imparted at a governmental level in order to reduce COVID-19 infections. At the same time, despite this opportunity, the digital grocery trade has not yet established itself nationwide in Germany. This can be attributed to a lack of investments, but also to inadequate digitization measures. A stronger synchronization between the digital and stationary offer, better integration of digital food services at a regional level as well as adapted, target group-appropriate digital solutions for the efficient breakdown of usage barriers will benefit service usage. The importance of stable food chains and distribution channels was illustrated by the COVID-19 pandemic. Further research should help to develop the digital food trade into a stable and sustainable supplementation of the stationary store.
Men are currently underrepresented in traditionally female care-oriented (communal) engagement such as taking parental leave, whereas they are overrepresented in traditionally male (agentic) engagement such as breadwinning or leadership. We examined to what extent different prototypical representations of men affect men’s self-reported parental leave-taking intentions and more generally the future they can imagine for themselves with regard to work and care roles (i.e., their possible selves). We expected prototypes of men that combine the two basic stereotype dimensions of agency and communion to increase men’s communal intentions. In two experiments (N1 = 132, N2 = 233), we presented male participants with contrived newspaper articles that described the ideal man of today with varying degrees of agency and communion (between-subjects design with four conditions; combined agentic and communal vs. agentic vs. communal vs. control condition). Results of Experiment 1 were in line with the main hypothesis that especially presenting a combination of agency and communion increases men’s expectations for communal engagement: As compared to a control condition, men expected more to engage in caretaking in the future, reported higher parental leave-taking intentions, and tended to expect taking longer parental leave. Experiment 2 only partially replicated these findings, namely for parental leave-taking intentions. Both experiments additionally provided initial evidence for a contrast effect in that an exclusive focus on agency also increased men’s self-reported parental leave-taking intentions compared to the control condition. Yet, exclusively emphasizing communion in prototypes of men did not affect men’s communal intentions, which were high to begin with. We further did not find evidence for preregistered mechanisms. We discuss conditions and explanations for the emergence of these mixed effects as well as implications for the communication of gendered norms and barriers to men’s communal engagement more broadly.
Invasive species play increasing roles worldwide. Invasions are considered successful when species establish and spread in their exotic range. Subsequently, dispersal is a major determinant of species’ range dynamics. Mermessus trilobatus, native to North America, has rapidly spread in Europe via aerial dispersal. Here we investigated the interplay of ecological and evolutionary processes behind its colonisation success.
First, we examined two possible ecological mechanisms. Similar to other invasive invertebrates, the colonisation success of Mermessus trilobatus might be related to human-induced habitat disturbance. Opposite to this expectation, our results showed that densities of Mermessus trilobatus decreased with soil disturbance in grasslands suggesting that its invasion success was not connected to a ruderal strategy. Further, invasive species often escape the ecological pressures from novel enemies in their exotic ranges. Unexpectedly, invasive Mermessus trilobatus was more sensitive to a native predator than native Erigone dentipalpis during our predator susceptibility trials. This indicates that the relation between the invasive spider and its native predator is dominated by prey naïveté rather than enemy release.
The remaining three chapters of the thesis investigated the dispersal behaviour of this invasive species. Hitherto, studies of passive aerial dispersal used wind as the primary dispersal-initiating factor despite a recent demonstration of the effects of the atmospheric electric fields on spiders’ pre-dispersal behaviour. During our experiments, only the wind facilitated the flight, although electric fields induced pre-dispersal behaviour in spiders. Consequently, studies around passive aerial dispersal should control electric fields but use wind as a stimulating factor.
Rapidly expanding species might be disproportionately distributed in their exotic range, with an accumulation of dispersive genotypes at the leading edge of their range. Such imbalanced spatial segregation is possible when the dispersal behaviour of expanding species is heritable. Our results showed that the dispersal traits of Mermessus trilobatus were heritable through both parents and for both sexes with recessive inheritance of high dispersal ability in this species.
Following the heritability experiments, we documented an accelerated spread of Mermessus trilobatus in Europe and tested whether dispersal, reproduction or competing ability was at the source of this pattern. Our results showed that the accumulation of more mobile but not reproductive or competitive genotypes at the expansion front of this invasive species gave rise to an accelerated range expansion by more than 1350 km in under 45 years.
Invasive Mermessus trilobatus is inferior to native sympatric species with respect to competing ability (Eichenberger et al., 2009), disturbance tolerance and predation pressure. Nevertheless, the species successfully established in its exotic range and spread by accelerating its expansion rate. Rapid reproduction that balances the high ecological pressures might be the other potential mechanism behind its colonisation success in Europe and deserves further investigation.
Agricultural plastic covers made from polyethylene (PE) and polypropylene (PP) provide increased yields and an improved crop quality. However, such covers are suspected of partially breaking down into smaller debris and thereby contributing to soil pollution with microplastics. To scrutinize this, we randomly sampled 240 topsoil cores (0–5 cm) from eight fields which were covered with fleeces, perforated foils, and plastic mulches for less than 2 years. Samples from the field periphery (50 m perimeter) served as a reference. Visual plastic debris > 2 mm was analyzed by Fourier transform infrared spectroscopy. Smaller, soil-associated plastic debris was dispersed from 50 g of fine soil (≤ 2 mm) using sodium hexametaphosphate solution and density-separated with saturated NaCl solution. The collected PE, PP, and polystyrene (PS) debris was selectively dissolved in a mixture of 1,2,4-trichlorobenzene and p-xylene at 150 °C and quantified by pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS). We counted six PE and PS fragments > 2 mm in two out of eight fields. By contrast, Py-GC/MS detected PE, PP, and PS contents in the fine soil of six fields (6 % of all samples). In three fields, PE levels of 3–35 mg kg−1 were potentially associated with the use of thinner and less durable perforated foils (40 µm thickness). This was slightly more pronounced at field edges where the plastic covers are turned and weighed down. By contrast, 50 µm thick PE films were not shown to emit any plastic debris. PP contents of 5–10 mg kg−1 were restricted to single observations in the field centers of three sites. At one site, we found expanded PS particles > 2 mm that concurred with elevated PS levels (8–19 mg kg−1) in the fine soil. Both PP and PS were distributed indistinctly across sites so that their source remained unresolved. In addition, the extent to which plastic contents of up to 7 mg kg−1 in the field periphery of some sites were attributed to wind drift from the covered fields or from external sources needs to be investigated in future studies. Our results suggest that the short-term use of thicker and more durable plastic covers should be preferred over thinner or perforated films to limit plastic emissions and accumulation in soil.
Abstract for the print-book: Walden, R. (2008). Architectural Psychology: School, University Campus, and Office Building of the Future. Lengerich: Pabst Science Publishers (in German). The need for display of self in architecture and for users' self-regulation of stress factors, which demonstrate that users crave individual control of their environment (cf. Flammer, 1990; Burger, 1992) motivated this study to use the concept of environmental control as a central criterion for the evaluation of built environment. It was applied to three case studies: a school, a university campus, and an office building. Advantages and disadvantages of the data- gathering methods of architectural Programming, User-Needs Analysis, and Post-Occupancy Evaluation were analyzed to highlight their significance in terms of Building Performance Evaluation as described by Preiser and Sc hramm (1997, 2005). The “Koblenz Architecture Questionnaire” was used as an instrument for assessing the built environment of the three case studies, and the study reports selected findings from these questionnaires. The investigation seeks to determine the effect of architecture - especially buildings' provisions for user control of environmental conditions - on user performance (cf. BOSTI studies, 1984, 2001) in three innovative buildings: the Waldorf School in Cologne, the new campus for the University in Koblenz, and the Office Tower of the Deutsche Post World Net AG in Bonn. Performance is measured in terms of (1) Lear ning and Work Efficiency, (2) Well-being, (3) Environmental Control, (4) Social Behavior (the latter just for the school project), and by means of 21 and 16 additional psychological criteria for success of the organization in the cases of the university and the office building, respectively. The study aims, among other things, at reassessing the theoretical concept of 'environmental control' and at making recommendations for both improvement of existing buildings and the design of new projects. Two central questions are: In User-Needs Analysis, what is the difference between the assessment of a building for its current use and its estimated performance in future? Do certain architectural features influence user assessments on the given performance criteria? In the studies, three mapping sentences were developed according to the 'facet approach' (Borg, 1996) as well as two systems to judge the quality of school and office buildings. Using these systems, information was obtained in all three studies to construct questionnaires. In the school study, teachers were asked 139 questions, pupils 86 questions. Responses were obtained from 26 teachers and 122 pupils. For the university, 147 students and 28 faculty members responded to 203 questions. For the office building, 56 student-experts were asked 254 questions. Characteristics of the built environment were rated using the following scale: +2 ☺☺ (very good “at present”, and accordingly very important “in the future”) down to –2 // (very bad “at present”, and very unimportant “in the future”). A general finding was a high and significant co rrelation between the responses for the three main performance criteria in all three case studies, especially for the 'importance for the future' aspect. This supports the conclusion that a perception of higher degree of environmental control by users will lead to an increased sense of well-being and consequently, there will also be a higher expectation of improved work or learning efficiency 'in the future'. The three studies further show for example that users in all three environments desire 'retreat opportunities' which may take the form of student offices in schools, niches and small group seating in classrooms, and sheltered seating in outdoor areas and work tables in the cafeteria for the university. For the offices, users wanted more visual privacy (less transparent office partitions in Combi Offices) for less visual control of their activities by supervisors and co-workers. The relationships found by the studies between the responses on the central performance criteria and the spatial characteristics of the three buildings support the contention that focused improvements in the built environment, especially with respect to features that enhance user control of environmental conditions, will influence users’ well-being as well as work performance and work or learning efficiency in a positive way.
The ongoing loss of species is a global threat to biodiversity, affecting ecosystems worldwide. This also concerns arthropods such as insects and spiders, which are especially endangered in agricultural ecosystems. Here, one of the main causing factors is management intensification. In areas with a high proportion of traditionally managed grassland, extensive hay meadows that are cut only once per year can still hold high levels of biodiversity, but are threatened by conversion into highly productive silage grassland. The Westerwald mountain range, western Germany, is such a region. In this thesis, I compare the local diversity of bees, beetles, hoverflies, leafhoppers, and spiders of five grassland management regimes along a gradient of land-use intensity. These comprise naturally occurring grassland fallows, three types of traditionally managed hay meadows, and intensively used silage grassland. By using three different sampling methods, I recorded ground-dwelling, flower-visiting, and vegetation-dwelling species. The results show that in most cases species richness and diversity are highest on fallows, whereas variation among different managed grassland types is very low. Also, for most sampled taxa, fallows harbour the most distinct species assemblages, while that of other management regimes are largely overlapping. Management has the largest effect on species composition, whereas environmental parameters are of minor importance. Long-term grassland fallows seem to be highly valuable for arthropod conservation, even in a landscape with a low overall land-use intensity, providing structural heterogeneity. In conclusion, such fallows should be subsidized agri-environmental schemes, to preserve insect and spider diversity.
For software engineers, conceptually understanding the tools they are using in the context of their projects is a daily challenge and a prerequisite for complex tasks. Textual explanations and code examples serve as knowledge resources for understanding software languages and software technologies. This thesis describes research on integrating and interconnecting
existing knowledge resources, which can then be used to assist with understanding and comparing software languages and software technologies on a conceptual level. We consider the following broad research questions that we later refine: What knowledge resources can be systematically reused for recovering structured knowledge and how? What vocabulary already exists in literature that is used to express conceptual knowledge? How can we reuse the
online encyclopedia Wikipedia? How can we detect and report on instances of technology usage? How can we assure reproducibility as the central quality factor of any construction process for knowledge artifacts? As qualitative research, we describe methodologies to recover knowledge resources by i.) systematically studying literature, ii.) mining Wikipedia, iii.) mining available textual explanations and code examples of technology usage. The theoretical findings are backed by case studies. As research contributions, we have recovered i.) a reference semantics of vocabulary for describing software technology usage with an emphasis on software languages, ii.) an annotated corpus of Wikipedia articles on software languages, iii.) insights into technology usage on GitHub with regard to a catalog of pattern and iv.) megamodels of technology usage that are interconnected with existing textual explanations and code examples.
This study examines the contribution of saving and credit cooperatives (SACCOS) on the improvement of members‘ socio economic development in Rwanda: Opportunities and challenges‖, Evidence from Umwalimu SACCO- Huye District‖. The appearance of saving and credit cooperatives or credit unions has been known as remedy for social ills rooted in poverty because of its efficiency in loans or credits dispensation, social equality for enhancement and reduction of poverty amongst low income earners. Therefore, millions and millions of poor people and non-bankable in developing countries (or third world countries) have been provided access to formal financial services through saving and credit cooperatives‘ programs.
The targeted population concerned by the study was 1,940 members of USACCO from which a sample of 92 respondents was purposively selected. The study has adopted a combination of correlation and descriptive research design. It has employed both quantitative and qualitative approaches. The study used both primary and secondary data. The primary data was collected using questionnaire and interview and, while secondary data was collected using documentations techniques whereby, Manual of procedures and Credit policies of USACCO and financial reports have been consulted. The analysis of data was done using SPSS version 21. The data was presented in form of tables, charts and graphs designed by SPSS v. 21. The bio-characteristics of respondents showed that, the majority of respondents were women with 55.4%, majority of respondents‘ age is between 26 to 45 years Furthermore, and majority 77.20% of respondents were married. 100% of respondents attended school, where the majority of respondents attended secondary school with certificate A2.
The study has revealed that Umwalimu SACCO services offered to its members have a positive effect on the improvement of members‘ welfare. It was found that USACCO services have slightly affected income level of members, assets acquired, access to education and medical care as well as small income generating activities established by members in Huye District. The analysis of data also revealed that there are some variables which have effected USACCO members‘ socio-economic status, these were listed as: Education background of a member, number of dependents, the occupation of a member, and number of loans got from USACCO, government programs against teachers‘ welfare, and membership duration played very important role on the improvement of standard living of teachers. All these variables were found to have positive effects on teachers‘ socio-economic status, except the family size of respondents.
In addition, the findings showed that, the majority of respondents confirmed that, they did not find opportunities to save with other financial institutions, and other respondents did not have access to loan from other financial institutions due to complicated loan requirements. In addition, after they
have joined USACCO, their deplorable status somewhat changed, both socially and economically which has contributed to the improvement of their welfare. Therefore, the study testified that, the welfare of USACCO members in terms of assets acquired, income increased was improved compared to situation before joining USACCO. The study concludes that ―the level of improvement of living conditions of teachers depends largely to the level of loan granted by USACCO to teachers and membership duration. If the level of teachers‘ loan and saving increases, there will be also improvement of teachers‘ wellbeing‖ and finally, USACCO financial service is a veritable instrument for better improvement of economic and social conditions of teachers. The study recommends that, USACCO should provide frequent and regular trainings on business management game to their members. This could help members for good management of their loans and reducing loan defaulters‘ cases observed at USACCO. Challenges observed were lack of physical collateral security required by USACCO, complicated loan requirements terms and conditions and insufficient trainings on business management game.
Social media provides a powerful way for people to share opinions and sentiments about a specific topic, allowing others to benefit from these thoughts and feelings. This procedure generates a huge amount of unstructured data, such as texts, images, and references that are constantly increasing through daily comments to related discussions. However, the vast amount of unstructured data presents risks to the information-extraction process, and so decision making becomes highly challenging. This is because data overload may cause the loss of useful data due to its inappropriate presentation and its accumulation. To this extent, this thesis contributed to the field of analyzing and detecting feelings in images and texts. And that by extracting the feelings and opinions hidden in a huge collection of image data and texts on social networks After that, these feelings are classified into positive, negative, or neutral, according to the features of the classified data. The process of extracting these feelings greatly helps in decision-making processes on various topics as will be explained in the first chapter of the thesis. A system has been built that can classify the feelings inherent in the images and texts on social media sites, such as people’s opinions about products and companies, personal posts, and general messages. This thesis begins by introducing a new method of reducing the dimension of text data based on data-mining approaches and then examines the sentiment based on neural and deep neural network classification algorithms. Subsequently, in contrast to sentiment analysis research in text datasets, we examine sentiment expression and polarity classification within and across image datasets by building deep neural networks based on the attention mechanism.
The role of alternative resources for pollinators and aphid predators in agricultural landscapes
(2021)
The world wide decline of insects is often associated with loss of natural and semi-natural habitat caused by intensified land-use. Many insects provide important ecosystem services to agriculture, such as pest control or pollination. To efficiently promote insects on remaining semi-natural habitat we need precise knowledge of their requirements to non-crop habitat. This thesis focuses on identifying
the most important semi-natural habitats (forest edges, grasslands, and semi-open habitats) for pollinators and natural enemies of crop pests with respect to their food resource requirements. Special
attention is given to floral resources and their spatio-temporal distribution in agricultural landscapes.
Floral resource maps might get closer at characterizing landscapes the way they are experienced by insects compared to classical habitat maps. Performance of the two map types was compared on the prediction of wild bees and natural enemies that consume nectar and pollen, identifying habitats of special importance in the process. In wild bees, influences of spatio-temporal floral resource availability were analysed as well as habitat preferences of specific groups of bees. Understanding dietary needs of natural enemies of crop pests requires additional knowledge on prey use. To this end, ladybird gut contents have been analysed by means of high-throughput sequencing for insight into aphid prey-use.
Results showed, that wild bees were predicted better by floral resource maps compared to classical habitat maps. Forest edge area, as well as floral resources in forest edges had positive effects on abundance and diversity of rare bees and important crop pollinators. Similar patterns were retained for grassland diversity. Especially early floral resources seemed to have positive effects on wild bees. Crops and fruit trees produced a resource pulse in April that exceeded floral resource availability in May and June by tenfold. Most floral resources in forest edges appeared early in the season, with the highest floral density per area. Grasslands provided the lowest amount of floral resources but highest diversity, which was evenly distributed over the season.
Despite natural enemies need for floral resources, classical habitat maps performed better at predicting natural enemies of crop pests compared to floral resource maps. Classical habitat maps revealed a positive effect of forest edge habitat on the abundance of pest enemies, which translated into improved aphid control. Results from gut content analysis reveal high portions of pest aphid species and nettle aphids as well as a broader insight into prey spectra retained from ladybirds collected from sticky traps compared to individuals collected by hand. The aphid specific primer designed for this purpose will be helpful for identifying aphid consumption by ladybirds in future studies.
Findings of this thesis show the potential of floral resource maps for understanding interactions of wild bees and the landscape but also indicate that natural enemies are limited by other resources. I would like to highlight the positive effects of forest edges for different groups of bees as well as natural enemies and their performance on pest control.
As a multilingual system,Wikipedia provides many challenges for academics and engineers alike. One such challenge is cultural contextualisation of Wikipedia content, and the lack of approaches to effectively quantify it. Additionally, what seems to lack is the intent of establishing sound computational practices and frameworks for measuring cultural variations in the data. Current approaches seem to mostly be dictated by the data availability, which makes it difficult to apply them in other contexts. Another common drawback is that they rarely scale due to a significant qualitative or translation effort. To address these limitations, this thesis develops and tests two modular quantitative approaches. They are aimed at quantifying culture-related phenomena in systems which rely on multilingual user-generated content. In particular, they allow to: (1) operationalise a custom concept of culture in a system; (2) quantify and compare culture-specific content- or coverage biases in such a system; and (3) map a large scale landscape of shared cultural interests and focal points. Empirical validation of these approaches is split into two parts. First, an approach to mapping Wikipedia communities of shared co-editing interests is validated on two large Wikipedia datasets comprising multilateral geopolitical and linguistic editor communities. Both datasets reveal measurable clusters of consistent co-editing interest, and computationally confirm that these clusters correspond to existing colonial, religious, socio economic, and geographical ties. Second, an approach to quantifying content differences is validated on a multilingual Wikipedia dataset, and a multi-platform (Wikipedia and Encyclopedia Britannica) dataset. Both are limited to a selected knowledge domain of national history. This analysis allows, for the first time on the large scale, to quantify and visualise the distribution of historical focal points in the articles on national histories. All results are cross-validated either by domain experts, or external datasets.
Main thesis contributions. This thesis: (1) presents an effort to formalise the process of measuring cultural variations in user-generated data; (2) introduces and tests two novel approaches to quantifying cultural contextualisation in multilingual data; (3) synthesises a valuable overview of literature on defining and quantifying culture; (4) provides important empirical insights on the effect of culture on Wikipedia content and coverage; demonstrates that Wikipedia is not contextfree, and these differences should not be treated as noise, but rather, as an important feature of the data. (5) makes practical service contributions through sharing data and visualisations.
Virtual reality is a growing field of interest as it provides a particular intuitive way of user-interaction. However, there are still open technical issues regarding latency — the delay between interaction and display reaction — and the trade-off between visual quality and frame-rate of real-time graphics, especially when taking visual effects like specular and semi-transparent surfaces and volumes into account. One solution, a distributed rendering setup, is presented in this thesis, in which the image synthesis is divided into an accurate but costly physically based rendering thread with a low refresh rate and a fast reprojection thread to remain a responsive interactivity with a high frame-rate. Two novel reprojection techniques are proposed that cover reflections and refractions produced by surface ray-tracing as well as volumetric light transport generated by volume ray-marching. The introduced setup can enhance the VR experience within several domains. In this thesis, three innovative training applications have been realized to investigate the added value of virtual reality to the three learning stages of observation, interaction and collaboration. For each stage an interdisciplinary curriculum, currently taught with traditional media, was transferred to a VR setting in order to investigate how virtual reality is capable of providing a natural, flexible and efficient learning environment
Thousands of chemicals from daily use are being discharged from civilization into the water cycle via different pathways. Ingredients of personal care products, detergents, pharmaceuticals, pesticides, and industrial chemicals thus find their way into the aquatic ecosystems and may cause adverse impacts on the ecology. Pharmaceuticals for instance, represent a central group of anthropogenic chemicals, because of their designed potency to interfere with physiological functions in organisms. Ecotoxicological effects from pharmaceutical burden have been verified in the past. Therapeutic groups with pronounced endocrine disrupting potentials such as steroid hormones gain increasing focus in environmental research as it was reported that they cause endocrine disruption in aquatic organisms even when exposed to environmentally relevant concentrations. This thesis considers the comprehensive investigation of the occurrence of corticosteroids and progestogens in wastewater treatment plant (WWTP) effluents and surface waters as well as the elucidation of the fate and biodegradability of these steroid families during activated sludge treatment. For the first goal of the thesis, a robust and highly sensitive analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed in order to simultaneously determine the occurrence of around 60 mineralocorticoids, glucocorticoids and progestogens in the aquatic environment. A special focus was set to the compound selection due to the diversity of marketed synthetic steroids. Some analytical challenges have been approved by individual approaches regarding sensitivity enhancement and compound stabilities. These results may be important for further research in environmental analysis of steroid hormones. Reliable and low quantification limits are the perquisite for the determination of corticosteroids and progestogens at relevant concentrations due to low consumption volumes and simultaneously low effect-based trigger values. Achieved quantification limits for all target analytes ranged between 0.02 ng/L and 0.5 ng/L in surface water and 0.05 ng/L to 5 ng/L in WWTP effluents. This sensitivity enabled the detection of three mineralocorticoids, 23 glucocorticoids and 10 progestogens within the sampling campaign around Germany. Many of them were detected for the first time in the environment, particularly in Germany and the EU. To the best of our knowledge, this in-depth steroid screening provided a good overview of single steroid burden and allowed for the identification of predominantly steroids of each steroid
type analyzed for the first time. The frequent detection of highly potent synthetic steroids (e.g. triamcinolone acetonide, clobetasol propionate, betamethasone valerate, dienogest, cyproterone acetate) highlighted insufficient removal during conventional Summary wastewater treatment and indicated the need for regulation to control their emission since the steroid concentrations were found to be above the reported effect-based trigger values for biota. Overall, the study revealed reliable environmental data of poorly or even not analyzed steroids. The results complement the existing knowledge in this field but also providednew information which can beused particularly for compound prioritization in ecotoxicological research and environmental analysis. Based on the data obtained from the monitoring campaign, incubation experiments were conducted to enable the comparison of the biodegradability and transformation processes in activated sludge treatment for structure-related steroids under aerobic and standardized experimental conditions. The compounds were accurately selected to cover manifold structural moieties of commonly used glucocorticoids, including non-halogenated and halogenated steroids, their mono- and diesters, and several acetonide-type steroids. This approach allowed for a structure-based interpretation of the results. The obtained biodegradation rate constants suggested large variations in the biodegradability (half-lifes ranged from < 0.5 h to > 14 d). An increasing stability was identified in the order from non-halogenated steroids (e.g. hydrocortisone), over 9α-halogenated steroids (e.g. betamethasone), to C17-monoesters (e.g. betamethasone 17-valerate, clobetasol propionate), and finally to acetonides (e.g. triamcinolone acetonide), thus suggesting a strong relationship of the biodegradability with the glucocorticoid structure. Some explanations for this behavior have been received by identifying the transformation products (TPs) and elucidating individual transformation pathways. The results revealed the identification of the likelihood of transformation reactions depending on the chemical steroid structure for the first time. Among the identified TPs, the carboxylates (e.g. TPs of fluticasone propionate, triamcinolone acetonide) have been shown persistency in the subsequent incubation experiments. The newly identified TPs furthermore were frequently detected in the effluents of full-scale wastewater treatment plants. These findings emphasized i) the transferability of the lab-scale degradation experiments to real world and that ii) insufficient removals may cause adverse effects in the aquatic environment due to the ability of the precursor steroids and TPs to interact with the endocrine system in biota. For the last goal, the conceptual study for glucocorticoids was applied to progestogens.
Here, two sub-types of the steroid family frequently used for hormonal contraception were selected (17α-hydroxyprogesterone and 19-norstestosterone type). The progestogens showed a fast and complete degradation within six hours, and thus empathizes pronounced biodegradability. However, cyproterone acetate and dienogest Summary have been found to be more recalcitrant in activated sludge treatment. This was consistent with their ubiquitously occurrence during the previous monitoring campaign. The elucidation of TPs again revealed some crucial information regarding the observed behavior and highlighted furthermore the formation of hazardous TPs. It was shown that 19-nortestosterone type steroids are able to undergo aromatization at ring A in contact with activated sludge, leading to the formation of estrogen-like TPs with a phenolic moiety at ring A. In the case of norethisterone the formation of 17α-ethinylestradiol was confirmed, which is a well-known potent synthetic estrogen with elevated ecotoxicological potency. Thus, the results indicated for the very first time an unknown source of estrogenic compounds, particularly for 17α-ethinylestradiol. In conclusion, some steroids were found to be very stable in activated sludge treatment, others degrade well, and others which do degrade but predominantly to active TPs depending on their chemical structure. Fluorinated acetal steroids such as triamcinolone acetonide and fluocinolone acetonide are poorly biodegradable, which is reflected in high concentrations detected ubiquitously in WWTP effluents. Endogenous steroids and their most related synthetic once such as hydrocortisone, prednisolone or 17α-hydroxyprogesterone are readily biodegradable. Regardless their high influent concentrations, they are almost completely removed in conventional WWTPs. Steroids between this range have been found to form elevated quantities of TPs which are partially still active, which particularly the case for betamethasone, fluticasone propionate, cyproterone acetate or dienogest. The thesis illustrates the need for an extensive evaluation of the environmental risks and carried out that corticosteroids and progestogens merit more attention in environmental regulatory and research than it is currently the case
The Web is an essential component of moving our society to the digital age. We use it for communication, shopping, and doing our work. Most user interaction in the Web happens with Web page interfaces. Thus, the usability and accessibility of Web page interfaces are relevant areas of research to make the Web more useful. Eye tracking is a tool that can be helpful in both areas, performing usability testing and improving accessibility. It can be used to understand users' attention on Web pages and to support usability experts in their decision-making process. Moreover, eye tracking can be used as an input method to control an interface. This is especially useful for people with motor impairment, who cannot use traditional input devices like mouse and keyboard. However, interfaces on Web pages become more and more complex due to dynamics, i.e., changing contents like animated menus and photo carousels. We need general approaches to comprehend dynamics on Web pages, allowing for efficient usability analysis and enjoyable interaction with eye tracking. In the first part of this thesis, we report our work on improving gaze-based analysis of dynamic Web pages. Eye tracking can be used to collect the gaze signals of users, who browse a Web site and its pages. The gaze signals show a usability expert what parts in the Web page interface have been read, glanced at, or skipped. The aggregation of gaze signals allows a usability expert insight into the users' attention on a high-level, before looking into individual behavior. For this, all gaze signals must be aligned to the interface as experienced by the users. However, the user experience is heavily influenced by changing contents, as these may cover a substantial portion of the screen. We delineate unique states in Web page interfaces including changing contents, such that gaze signals from multiple users can be aggregated correctly. In the second part of this thesis, we report our work on improving the gaze-based interaction with dynamic Web pages. Eye tracking can be used to retrieve gaze signals while a user operates a computer. The gaze signals may be interpreted as input controlling an interface. Nowadays, eye tracking as an input method is mostly used to emulate mouse and keyboard functionality, hindering an enjoyable user experience. There exist a few Web browser prototypes that directly interpret gaze signals for control, but they do not work on dynamic Web pages. We have developed a method to extract interaction elements like hyperlinks and text inputs efficiently on Web pages, including changing contents. We adapt the interaction with those elements for eye tracking as the input method, such that a user can conveniently browse the Web hands-free. Both parts of this thesis conclude with user-centered evaluations of our methods, assessing the improvements in the user experience for usability experts and people with motor impairment, respectively.
Human action recognition from a video has received growing attention in computer vision and has made significant progress in recent years. Action recognition is described as a requirement to decide which human actions appear in videos. The difficulties involved in distinguishing human actions are due to the high complexity of human behaviors as well as appearance variation, motion pattern variation, occlusions, etc. Many applications use human action recognition on captured video from cameras, resulting in video surveillance systems, health monitoring, human-computer interaction, and robotics. Action recognition based on RGB-D data has increasingly drawn more attention to it in recent years. RGB-D data contain color (Red, Green, and Blue (RGB)) and depth data that represent the distance from the sensor to every pixel in the object (object point). The main problem that this thesis deals with is how to automate the classification of specific human activities/actions through RGB-D data. The classification process of these activities utilizes a spatial and temporal structure of actions. Therefore, the goal of this work is to develop algorithms that can distinguish these activities by recognizing low-level and high-level activities of interest from one another. These algorithms are developed by introducing new features and methods using RGB-D data to enhance the detection and recognition of human activities. In this thesis, the most popular state-of-the-art techniques are reviewed, presented, and evaluated. From the literature review, these techniques are categorized into hand-crafted features and deep learning-based approaches. The proposed new action recognition framework is based on these two categories that are approved in this work by embedding novel methods for human action recognition. These methods are based on features extracted from RGB-D data that are
evaluated using machine learning techniques. The presented work of this thesis improves human action recognition in two distinct parts. The first part focuses on improving current successful hand-crafted approaches. It contributes into two significant areas of state-of-the-art: Execute the existing feature detectors, and classify the human action in the 3D spatio-temporal domains by testing a new combination of different feature representations. The contributions of this part are tested based on machine learning techniques that include unsupervised and supervised learning to evaluate this suitability for the task of human action recognition. A k-means clustering represents the unsupervised learning technique, while the supervised learning technique is represented by: Support Vector Machine, Random Forest, K-Nearest Neighbor, Naive Bayes, and Artificial Neural Networks classifiers. The second part focuses on studying the current deep-learning-based approach and how to use it with RGB-D data for the human action recognition task. As the first step of each contribution, an input video is analyzed as a sequence of frames. Then, pre-processing steps are applied to the video frames, like filtering and smoothing methods to remove the noisy data from each frame. Afterward, different motion detection and feature representation methods are used to extract features presented in each frame. The extracted features
are represented by local features, global features, and feature combination besides deep learning methods, e.g., Convolutional Neural Networks. The feature combination achieves an excellent accuracy performance that outperforms other methods on the same RGB-D datasets. All the results from the proposed methods in this thesis are evaluated based on publicly available datasets, which illustrate that using spatiotemporal features can improve the recognition accuracy. The competitive experimental results are achieved overall. In particular, the proposed methods can be better applied to the test set compared to the state-of-the-art methods using the RGB-D datasets.
We consider variational discretization of three different optimal control problems.
The first being a parabolic optimal control problem governed by space-time measure controls. This problem has a nice sparsity structure, which motivates our aim to achieve maximal sparsity on the discrete level. Due to the measures on the right hand side of the partial differential equation, we consider a very weak solution theory for the state equation and need an embedding into the continuous functions for the pairings to make sense. Furthermore, we employ Fenchel duality to formulate the predual problem and give results on solution theory of both the predual and the primal problem. Later on, the duality is also helpful for the derivation of algorithms, since the predual problem can be differentiated twice so that we can apply a semismooth Newton method. We then retrieve the optimal control by duality relations.
For the state discretization we use a Petrov-Galerkin method employing piecewise constant states and piecewise linear and continuous test functions in time. For the space discretization we choose piecewise linear and continuous functions. As a result the controls are composed of Dirac measures in space-time, centered at points on the discrete space-time grid. We prove that the optimal discrete states and controls converge strongly in L^q and weakly-* in Μ, respectively, to their smooth counterparts, where q ϵ (1,min{2,1+2/d}] is the spatial dimension. The variational discrete version of the state equation with the above choice of spaces yields a Crank-Nicolson time stepping scheme with half a Rannacher smoothing step.
Furthermore, we compare our approach to a full discretization of the corresponding control problem, precisely a discontinuous Galerkin method for the state discretization, where the discrete controls are piecewise constant in time and Dirac measures in space. Numerical experiments highlight the sparsity features of our discrete approach and verify the convergence results.
The second problem we analyze is a parabolic optimal control problem governed by bounded initial measure controls. Here, the cost functional consists of a tracking term corresponding to the observation of the state at final time. Instead of a regularization term for the control in the cost functional, we consider a bound on the measure norm of the initial control. As in the first problem we observe a sparsity structure, but here the control resides only in space at initial time, so we focus on the space discretization to achieve maximal sparsity of the control. Again, due to the initial measure in the partial differential equation, we rely on a very weak solution theory of the state equation.
We employ a dG(0) approximation of the state equation, i.e. we choose piecewise linear and continuous functions in space, which are piecewise constant in time for our ansatz and test space. Then, the variational discretization of the problem together with the optimality conditions induce maximal discrete sparsity of the initial control, i.e. Dirac measures in space. We present numerical experiments to illustrate our approach and investigate the sparsity structure
As third problem we choose an elliptic optimal control governed by functions of bounded variation (BV) in one space dimension. The cost functional consists of a tracking term for the state and a BV-seminorm in terms of the derivative of the control. We derive a sparsity structure for the derivative of the BV control. Additionally, we utilize the mixed formulation for the state equation.
A variational discretization approach with piecewise constant discretization of the state and piecewise linear and continuous discretization of the adjoint state yields that the derivative of the control is a sum of Dirac measures. Consequently the control is a piecewise constant function. Under a structural assumption we even get that the number of jumps of the control is finite. We prove error estimates for the variational discretization approach in combination with the mixed formulation of the state equation and confirm our findings in numerical experiments that display the convergence rate.
In summary we confirm the use of variational discretization for optimal control problems with measures that inherit a sparsity. We are able to preserve the sparsity on the discrete level without discretizing the control variable.
This thesis addresses the reduced basis methods for parametrized quasilinear elliptic and parabolic partial differential equations with strongly monotone differential operator. It presents all of the ingredients of the reduced basis method: basis generation for reduced basis approximation, certification of the approximation error by suitable a-posteriori error control and an Offine-Online decomposition. The methodology is further applied to the magnetostatic and magnetoquasistatic approximations of Maxwell’s equations and its validity is confirmed by numerical examples.
Cultural eutrophication due to excessive inputs of nutrients seriously threatens aquatic ecosystems worldwide and is one of the major anthropogenic stressors on aquatic biota in European rivers. In streams and shallow rivers, its effects include excessive periphyton growth, which causes biological clogging and thereby oxygen depletion in the hyporheic zone. The result is a serious degradation of habitat quality for benthic invertebrates as well as for the eggs and larvae of gravel-spawning fish. Unlike in standing waters, efficient tools for controlling eutrophication in rivers are lacking. However, top-down control of the food-web by manipulating fish stocks, similar to the biomanipulation successfully applied in lakes, offers a promising approach to mitigating the effects of eutrophication in shallow rivers, especially those in which major reductions in nutrient inputs are not feasible. The overall aim of this thesis was to assess the potential for top-down control by two large cypriniform fish, the common nase (Chondrostoma nasus), the only obligate herbivorous fish species in European rivers, and the omnivorous European chub (Squalius cephalus), to mitigate the effects of eutrophication in medium-sized rivers. I therefore conducted field experiments on different spatial and temporal scales in the hyporhithral zone of a eutrophic gravel-bed river. Generally, the results of those experiments revealed the crucial role of fish-mediated top-down effects in river food webs. In a 4-year reach-scale experiment, the key contribution of my thesis, the enhancement of fish densities significantly increased both oxygen availability and water exchange in the upper layer of the hyporheic zone, even though the top-down effects of the fish on periphyton biomass were relatively small. These findings were supported by those of a 4-week mesocosm experiment, which also provided insights into the mechanisms underlying the mitigation of eutrophication effects by nase and chub. The top-down effects of both fish species reduced hyporheic oxygen depletion, suggesting a reduction of biological clogging. The positive effects of herbivorous nase on hyporheic oxygen availability could be attributed to benthic grazing, whereas the reduction of hyporheic oxygen depletion in the presence of omnivorous chub was best explained by the enhanced bioturbation induced by the fish’s benthic foraging. Overall, the results of my thesis demonstrate that biomanipulation achieved by enhancing herbivorous and omnivorous fish stocks can mitigate the effects of eutrophication in medium-sized European rivers. The results may be the first step towards the establishment of biomanipulation as a supportive management tool for eutrophication control in running waters and therefore as a strategy to preserve aquatic biodiversity.
Vertebrate biodiversity is rapidly decreasing worldwide with amphibians being the most endangered vertebrate group. In the EU, 21 of 89 amphibian species are recognized as being endangered. The intensively used European agricultural landscape is one of the major causes for these declines. As agriculture represents an essential habitat for amphibians, exposure to pesticides can have adverse effects on amphibian populations. Currently, the European risk assessment of pesticides for vertebrates requires specific approaches for fish regarding aquatic vertebrate toxicity and birds as well as mammals for terrestrial vertebrate toxicity but does not address the unique characteristics of amphibians. Therefore, the overall goal of this thesis was to investigate the ecotoxicological effects of pesticides on Central European anuran amphibians. For this, effects on aquatic and terrestrial amphibian life stages as well as on reproduction were investigated. Then, in anticipation of a risk assessment of pesticides for amphibians, this thesis discussed potential regulatory risk assessment approaches.
For the investigated pesticides and amphibian species, it was observed that the acute aquatic toxicity of pesticides can be addressed using the existing aquatic risk assessment approach based on fish toxicity data. However, lethal as well as sublethal effects were observed in terrestrial juveniles after dermal exposure to environmentally realistic pesticide concentrations, which cannot be covered using an existing risk assessment approach. Therefore, pesticides should also be evaluated for potential terrestrial toxicity using risk assessment tools before approval. Additionally, effects of co-formulants and adjuvants of pesticides need specific consideration in a future risk assessment as they can increase toxicity of pesticides to aquatic and terrestrial amphibian stages. The chronic duration of combined aquatic and terrestrial exposure was shown to affect amphibian reproduction. Currently, such effects cannot be captured by the existing risk assessment as data involving field scenarios analysing effects of multiple pesticides on amphibian reproduction are too rare to allow comparison to data of other terrestrial vertebrates such as birds and mammals. In the light of these findings, future research should not only address acute and lethal effects, but also chronic and sublethal effects on a population level. As pesticide exposure can adversely affect amphibian populations, their application should be considered even more carefully to avoid further amphibian declines. Overall, this thesis emphasizes the urgent need for a protective pesticide risk assessment for amphibians to preserve and promote stable amphibian populations in agricultural landscapes.
Enterprise collaboration platforms are increasingly gaining importance in organisations. Integrating groupware functionality and enterprise social software (ESS), they have substantially been transforming everyday work in organisations. While traditional collaboration systems have been studied in Computer Supported Cooperative Work (CSCW) for many years, the large-scale, infrastructural and heterogeneous nature of enterprise collaboration platforms remains uncharted. Enterprise collaboration platforms are embedded into organisations’ digital workplace and come with a high degree of complexity, ambiguity, and generativity. When introduced, they are empty shells with no pre-determined purposes of use. They afford interpretive flexibility, and thus are shaping and being shaped by and in their social context. Outcomes and benefits emerge and evolve over time in an open-ended process and as the digital platform is designed through use. In order to make the most of the platform and associated continuous digital transformation, organisations have to develop the necessary competencies and capabilities.
Extant literature on enterprise collaboration platforms has proliferated and provide valuable insights on diverse topics, such as implementation strategies, adoption hurdles, or collaboration use cases, however, they tend to disregard their evolvability and related multiple time frames and settings. Thus, this research aims to identify, investigate, and theorise the ways that enterprise collaboration platforms are changing over time and space and the ways that organisations build digital transformation capabilities. To address this research aim two different case study types are conducted: i) in-depth longitudinal qualitative case study, where case narratives and visualisations capturing hard-to-summarise complexities in the enterprise collaboration platform evolution are developed and ii) multiple-case studies to capture, investigate, and compare cross-case elements that contribute to the shaping of enterprise collaboration platforms in different medium-sized and large organisations from a range of industries. Empirical data is captured and investigated through a multi-method research design (incl. focus groups, surveys, in-depth interviews, literature reviews, qualitative content analysis, descriptive statistics) with shifting units of analysis. The findings reveal unique change routes with unanticipated outcomes and transformations, context-specific change strategies to deal with multiple challenges (e.g. GDPR, works council, developments in the technological field, competing systems, integration of blue-collar workers), co-existing platform uses, and various interacting actors from the immediate setting and broader context. The interpretation draws on information infrastructure (II) as a theoretical lens and related sociotechnical concepts and perspectives (incl. inscriptions, social worlds, biography of artefacts). Iteratively, a conceptual model of the building of digital transformation capabilities is developed, integrating the insights gained from the study of enterprise collaboration platform change and developed monitoring change tools (e.g. MoBeC framework). It assists researchers and practitioners in understanding the building of digital transformation capabilities from a theoretical and practical viewpoint and organisations implement the depicted knowledge in their unique digital transformation processes.
Social media has changed how customers, businesses, employees, and job seekers form their reputation perceptions of a company, that is, how they form their evaluative judgements about a company’s products, services and behaviors towards constituencies. In pre-social media times, companies had control over what they communicated to their stakeholders, for example, by using corporate websites to convey a predefined image. With social media, multiple opinions, experiences, and company perceptions reach the wider public via multiple channels such as Twitter, Facebook, and other social networking sites that enable user-generated content. Although companies usually try to nurture an online reputation by running their own Facebook and Twitter profiles, a large amount of online content related to a company is produced by social media users and thus is beyond companies’ control. This habilitation thesis is devoted to studying consumer and employee responses to employee behavior in social media. Across eight different articles, with multiple studies each, this thesis aims to draw a full picture of how employee behavior in social media affects customers, other employees, job seekers, and the employing company as a whole.
The Stereotype Content Modell (SCM; Fiske et al., 2002) proposes two fundamental dimensions of social evaluation: Warmth, or the intentions of the target, and Competence, or the ability to enact these intentions. The practical applications of the SCM are very broad and have led to an assumption of universality of warmth and competence as fundamental dimensions of social evaluation.
This thesis has identified five mainly methodological shortcomings of the current SCM research and literature: (I) An insufficient initial scale development; (II) the usage of varying warmth and competence scales without sufficient scale property assessment in later research; (III) the dominant application of first-generation analytical approaches; (IV) the insufficient definition and empirical proof for the SCM’s assumption of universality; and (V) the limited application of the SCM for some social targets. These shortcomings were addressed in four article manuscripts strictly following open science recommendations.
Manuscript # 1 re-analysed published research using English SCM measures to investigate the measurement properties of the used warmth and competence scales. It reported the scales’ reliability, dimensionality and comparability across targets as well as the indicator-based parameter performance in a (multiple group) confirmatory factor analysis framework. The findings indicate that about two thirds of all re-analysed scales do not show the theoretically expected warmth and competence dimensionality. Moreover, only about eleven per cent allowed meaningful mean value comparisons between targets. Manuscript # 2 presents a replication of Manuscript # 1 in the national and language of German(y) generating virtually identical results as Manuscript # 1 did. Manuscript # 3 investigated the stereotype content of refugee subgroups in Germany. We showed that refugees was generally perceived unfavourably in terms of warmth and competence, but that the stereotype content varied based on the refugees’ geographic origin, religious affiliation, and flight motive. These results were generated using a reliability-corrected approach to compare mean values named alignment optimisation procedure. Manuscript # 4 developed and tested a high-performing SCM scale assessing occupational stereotypes a number of exploratory and confirmatory factor analyses.
Previous research concerned with early science education revealed that guided play can support young children’s knowledge acquisition. However, the questions whether guided play maintains other important prerequisites such as children’s science self-concept and how guided play should be implemented remain unanswered. The present dissertation encompasses three research articles that investigated 5- to 6-year-old children’s science knowledge, science theories, and science self-concept in the stability domain and their relation to interindividual prerequisites. Moreover, the articles examined whether children’s science knowledge, science theories, and science self-concept can be supported by different play forms, i.e., guided play with material and verbal scaffolds, guided play with material scaffolds, and free play. The general introduction of the present dissertation first highlights children’s cognitive development, their science self-concept, and interindividual prerequisites, i.e., fluid and crystallised intelligence, mental rotation ability, and interest in block play. These prerequisites are applied to possible ways of supporting children during play. The first article focused on the measurement of 5-to-6-year-old children’s stability knowledge and its relation to interindividual prerequisites. Results suggested that children’s stability knowledge could be measured reliably and validly, and was related to their fluid and crystallised intelligence. The second article was concerned with the development of children’s intuitive stability theories over three points of measurement and the effects of guided and free play, children’s prior theories as well as their intelligence on these intuitive theories. Results implied that guided play with material and verbal scaffolds supported children’s stability theories more than the other two play forms, i.e., guided play with material scaffolds and free play. Moreover, consistency of children’s prior theories, their fluid and crystallised intelligence were related to children’s theory adaptation after the intervention. The third article focused on the effect of the playful interventions on children’s stability knowledge and science self-concept over three points of measurement. Furthermore, the reciprocal effects between knowledge acquisition and science self-concept were investigated. Results implied that guided play supported knowledge acquisition and maintained children’s science self-concept. Free play did not support children’s stability knowledge and decreased children’s science self-concept. No evidence for reciprocal effects between children’s stability knowledge and their science self-concept was found. Last, in a general discussion, the findings of the three articles are combined and reflected amidst children’s cognitive development. Summarising, the present dissertation shows that children’s science knowledge, science theories, and science self-concept can be supported through guided play that considers children’s cognitive development.
Real-time operating systems for mixed-criticality systems
must support different types of software, such as
real-time applications and general purpose applications,
and, at the same time, must provide strong spatial and
temporal isolation between independent software components.
Therefore, state-of-the-art real-time operating systems
focus mainly on predictability and bounded worst-case behavior.
However, general purpose operating systems such as Linux
often feature more efficient---but less deterministic---mechanisms
that significantly improve the average execution time.
This thesis addresses the combination of the two contradicting
requirements and shows thread synchronization mechanisms
with efficient average-case behavior, but without sacrificing
predictability and worst-case behavior.
This thesis explores and evaluates the design space of fast paths
in the implementation of typical blocking synchronization
mechanisms, such as mutexes, condition variables, counting
semaphores, barriers, or message queues. The key technique here
is to avoid unnecessary system calls, as system calls have high
costs compared to other processor operations available in user
space, such as low-level atomic synchronization primitives.
In particular, the thesis explores futexes, the state-of-the-art
design for blocking synchronization mechanisms in Linux
that handles the uncontended case of thread synchronization
by using atomic operations in user space and calls into the
kernel only to suspend and wake up threads. The thesis also
proposes non-preemptive busy-waiting monitors that use an
efficient priority ceiling mechanism to prevent the lock holder
preemption problem without using system calls, and according
low-level kernel primitives to construct efficient wait and
notify operations.
The evaluation shows that the presented approaches
improve the average performance comparable
to state-of-the-art approaches in Linux.
At the same time, a worst-case timing analysis shows
that the approaches only need constant or bounded temporal
overheads at the operating system kernel level.
Exploiting these fast paths is a worthwhile approach
when designing systems that not only have to fulfill
real-time requirements, but also best-effort workloads.
Method development for the quantification of pharmaceuticals in aqueous environmental matrices
(2021)
As a consequence of the world population increase and the resulting water scarcity, water quality is the object of growing attention. In that context, organic anthropogenic molecules — often defined as micropollutants— represent a threat for water resources. Among them, pharmaceuticals are the object of particular concerns due to their permanent discharge, their increasing consumption and their effect-based structures. Pharmaceuticals are mainly introduced in the environment via wastewater treatment plants (WWTPs), along with their metabolites and the on-site formed transformation products (TPs). Once in the aquatic environment, they partition between the different environmental compartments in particular the aqueous phase, suspended particulate matter(SPM) and biota. In the last decades, pharmaceuticals have been widely investigated in the water phase. However, extreme polar pharmaceuticals have rarely been monitored due to the lack of robust analytical methods. Moreover, metabolites and TPs have seldom been included in routine analysis methods although their environmental relevance is proven. Furthermore, pharmaceuticals have been only sporadically investigated in SPM and biota and adequate multi-residue methods are lacking to obtain comprehensive results about their occurrence in these matrices. This thesis endeavors to cover these gaps of knowledge by the development of generic multi-residue methods for pharmaceuticals determination in the water phase, SPM and biota and to evaluate the occurrence and partition of pharmaceuticals into these compartments. For a complete overview, a particular focus was laid on extreme polar pharmaceuticals, pharmaceutical metabolites and TPs. In total, three innovative multi-residue methods were developed, they include analytes covering a broad range of physico-chemical properties. First, a reliable multi-residue method was developed for the analysis of extreme polar pharmaceuticals, metabolites and TPs dissolved in water. The selected analytes covered a significant range of elevated polarity and the method would be easily expendable to further analytes. This versatility could be achieved by the utilization of freeze-drying as sample preparation and zwitterionic hydrophilic interaction liquid chromatography (HILIC) in gradient elution mode. The suitability of HILIC chromatography to simultaneously quantify a large range of micropollutants in aqueous environmental samples was thoroughly studied. Several limitations were pointed out: a very complex and time-consuming method development, a very high sensitivity with regards to modification of the acetonitrile to water ratio in the eluent or the diluent and high positive matrix effects for certain analytes. However, these limitations can be overcome by the utilization of a precise protocol and appropriate labeled internal standards. They are overmatched by the benefits of HILIC which permits the chromatographic separation of extreme polar micropollutants. Investigation of environmental samples showed elevated concentrations of the analytes in the water phase. In particular, gabapentin, metformin, guanylurea and oxypurinol were measured at concentrations in the µg/L range in surface water. Subsequently, a reliable multi-residue method was established for the determination of 57 pharmaceuticals, 47 metabolites and TPs sorbed to SPM down to the low ng/g range. This method was conceived to cover a large range of polarity in particular with the inclusion of extreme polar pharmaceuticals. The extraction procedure was based on pressurized liquid extraction (PLE) followed by a clean-up via solvent exchange and detection via direct injection-reversed-phase LC-MS/MS and freeze-drying HILIC-MS/MS. Pharmaceutical sorption was examined using laboratory experiments. Derived distribution coefficients Kd varied by five orders of magnitude among the analytes and confirmed a high sorption potential for positively charged and nonpolar pharmaceuticals. The occurrence of pharmaceuticals in German rivers SPM was evaluated by the investigation of annual composite SPM samples taken at four sites at the river Rhine and one site at the river Saar between the years 2005 and 2015. It revealed the ubiquitous presence of pharmaceuticals sorbed to SPM in these rivers. In particular, positively charged analytes, even very polar and nonpolar pharmaceuticals showed appreciable concentrations. For many pharmaceuticals, a distinct correlation was observed between the annual quantities consumed in Germany and the concentrations measured in SPM. Studies of composite SPM spatial distribution permitted to get hints about specific industrial discharge by comparing the pollution pattern along the river. For the first time, these results showed the potential of SPM for the monitoring of positively charged and nonpolar pharmaceuticals in surface water. Finally, a reliable and generic multi residue method was developed to investigate 35 pharmaceuticals and 28 metabolites and TPs in fish plasma, fish liver and fish fillet. For this matrix, it was very challenging to develop an adequate clean-up allowing for the sufficient separation of the matrix disturbances from the analytes. In the final method, fish tissue extraction was performed by cell disruption followed by a non-discriminating clean-up based on silica gel solid-phase extraction(SPE) and restrictive access media (RAM) chromatography. Application of the developed method to the measurement of bream and carp tissues from German rivers revealed that even polar micropollutants such as pharmaceuticals are ubiquitously present in fish tissues. In total, 17 analytes were detected for the first time in fish tissues, including 10 metabolites/TPs. The importance of monitoring metabolites and TPs in fish tissues was confirmed with their detection at similar concentrations as their parents. Liver and fillet were shown to be appropriate for the monitoring of pharmaceuticals in fish, whereas plasma is more inconvenient due to very low concentrations and collection difficulties. Elevated concentrations of certain metabolites suggest possible formation of human metabolites in fish. Measured concentrations indicate a low bioaccumulation potential for pharmaceuticals in fish tissues.
Successful export sectors in manufacturing and agribusiness are important drivers of structural transformation in Sub-Sahara African countries. Backed by industrial policies and active state involvement, a small number of successful productive export sectors has emerged in Sub-Saharan Africa. This thesis asks the question: How do politics shape the promotion of export-driven industrialisation and firm-level upgrading in Sub-Saharan Africa? It exemplifies this question with an in-depth, qualitative study of the cashew processing industry in Mozambique in the period from 1991 until 2019. Mozambique used to be one of the world’s largest producers and processors of cashew nuts in the 1960s and 1970s. At the end of the 20th century, the cashew processing industry broke down completely but has re-emerged as one of the country’s few successful agro-processing exports.
The thesis draws on theoretical approaches from the fields of political science, notably the political settlements framework, global value chain analysis and the research on technological capabilities to explore why the Mozambican Government supported the cashew processing industry and how Mozambican cashew processors acquired the technological capabilities needed to access the global cashew value chain and to upgrade. It makes an important theoretical contribution by linking the political settlements framework and the literature on upgrading in global value chains to study how politics shaped productive sector promotion and upgrading in the Mozambican cashew processing industry. The findings of the thesis are based on extensive primary data, including 58 expert interviews and 10 firm surveys, that was collected in Mozambique in 2018 as well as a broad base of secondary literature.
The thesis argues that the Mozambican Government supported the cashew processing industry because it became important for the Government’s political survival. Promoting the cashew sector formed part of an electoral strategy for the ruling FRELIMO coalition and a means to keep FRELIMO factions united by offering economic opportunities to key constituencies. In 1999, it adopted a protectionist cashew law that created strong incentives for cashew processing in Mozambique. This not only facilitated the re-emergence of the cashew processing industry after its breakdown. The law and the active involvement of the National Cashew Institute (INCAJU) also affected the governance of the local cashew value chain, the creation of backward linkages, and the upgrading paths of cashew processors. The findings of the thesis suggest that the cashew law reduced the pressure on the cashew processing industry to upgrade. The law further created opportunities for formal and informal rent creation for members of the political elite and lower level FRELIMO officials that prevented a far-reaching reform of the law. The thesis shows that international buyers do not promote upgrading among Sub-Sahara African firms in global value chains with market-based or modular governance. Moreover, firms that operate in countries where industrial policies are not enforced effectively cannot draw on the support of government institutions to enhance their capabilities and to upgrade. Firms therefore mainly depended on costly learning channels at firm level, e.g. learning by doing or hiring skilled labour, and/or on technical assistance from donors to build the technological capabilities needed to access global value chains and to remain competitive.
The findings of the thesis suggest that researchers, governments, development practitioners and consultants need to rethink their understanding of upgrading in GVCs in four ways. First, they need to move away from understanding upgrading in terms of moving towards more complex, higher value-added activities in GVCs (functional upgrading). Instead, it is important to consider the potential of other, more realistic types of upgrading for firms in low-income countries, such reducing risks by diversifying suppliers and buyers or increasing rewards by making production processes more efficient. Second, they need to replace an overly positive view on upgrading that neglects possible side-effects at sector and/or country level. Third, GVC participation on its own does not promote upgrading among local supplier firms in Sub-Saharan Africa. The interests of lead firms and Sub-Sahara African supplier firms may not be aligned or even conflicting. Targeted industrial policies and the creation of institutions that effectively promote capability building among firms therefore become even more important. Finally, upgrading needs to be understood as a process that is not only shaped by interactions between firms, but also by local domestic politics.
The findings of the thesis are highly relevant for scholars from the fields of political science, development studies, and economics. Its practical implications and tools, e.g. a technological capabilities matrix for the cashew industry, are of interest for development practitioners, members of public institutions in Sub-Sahara African countries, local entrepreneurs, and representatives of local business associations that are involved in promoting export sectors and upgrading among local firms.
Artificial intelligence (AI) is of rising importance in these days. AI is increasingly used in various company fields. Nonetheless, no high-quality scientific sources could be found stating the use of AI in the field of leadership. This research gap is addressed with this elaboration by performing expert interviews with leaders. In total seventeen companies could be questioned. The results indicate that AI is not widely used in leadership yet since only one company uses it currently and just about 10% of the participants plan the implementation in the closer feature. While the following items ex- plain why companies want to use AI in leadership: Chances for automation, time and cost savings, many important disadvantages and issues prevent companies from actively using it now: No areas of application are known, no need justifies the use, human interactions as a key aspect of leadership is reduced and it is hard to collect all necessary data. Beyond that, it was aimed to identify changes in the field of leadership through the use of AI. This objective could not be addressed due to the limited number of participants using AI in leadership.
Keywords: Leadership, artificial intelligence, transformation, state-of-use
Water scarcity is already an omnipresent problem in many parts of the world, especially in sub-Saharan Africa. The dry years 2018 and 2019 showed that also in Germany water resources are finite. Projections and predictions for the next decades indicate that renewal rates of existing water resources will decline due the growing influence of climate change, but that water extraction rates will increase due to population growth. It is therefore important to find alternative and sustainable methods to make optimal use of the water resources currently available. For this reason, the reuse of treated wastewater for irrigation and recharge purposes has become one focus of scientific research in this field. However, it must be taken into account that wastewater contains so-called micropollutants, i.e., substances of anthropogenic origin. These are, e.g., pharmaceuticals, pesticides and industrial chemicals which enter the wastewater, but also metabolites that are formed in the human body from pharmaceuticals or personal care products. Through the treatment in wastewater treatment plants (WWTPs) as well as through chemical, biological and physical processes in the soil passage during the reuse of water, these micropollutants are transformed to new substances, known as transformation products (TPs), which further broaden the number of contaminants that can be detected within the whole water cycle.
Despite the fact that the presence of human metabolites and environmental TPs in untreated and treated wastewater has been known for a many years, they are rarely included in common routine analysis methods. Therefore, a first goal of this thesis was the development of an analysis method based on liquid chromatography - tandem mass spectrometry (LC-MS/MS) that contains a broad spectrum of frequently detected micropollutants including their known metabolites and TPs. The developed multi-residue analysis method contained a total of 80 precursor micropollutants and 74 metabolites and TPs of different substance classes. The method was validated for the analysis of different water matrices (WWTP influent and effluent, surface water and groundwater from a bank filtration site). The influence of the MS parameters on the quality of the analysis data was studied. Despite the high number of analytes, a sufficient number of datapoints per peak was maintained, ensuring a high sensitivity and precision as well as a good recovery for all matrices. The selection of the analytes proved to be relevant as 95% of the selected micropollutants were detected in at least one sample. Several micropollutants were quantified that were not in the focus of other current multi-residue analysis methods (e.g. oxypurinol). The relevance of including metabolites and TPs was demonstrated by the frequent detection of, e.g., clopidogrel acid and valsartan acid at higher concentrations than their precursors, the latter even being detected in samples of bank filtrate water.
By the integration of metabolites, which are produced in the body by biological processes, and biological and chemical TPs, the multi-residue analysis method is also suitable for elucidating degradation mechanisms in treatment systems for water reuse that, e.g., use a soil passage for further treatment. In the second part of the thesis, samples from two treatment systems based on natural processes were analysed: a pilot-scale above-ground sequential biofiltration system (SBF) and a full-scale soil aquifer treatment (SAT) site. In the SBF system mainly biological degradation was observed, which was clearly demonstrated by the detection of biological TPs after the treatment. The efficiency of the degradation was improved by an intermediate aeration, which created oxic conditions in the upper layer of the following soil passage. In the SAT system a combination of biodegradation and sorption processes occurred. By the different behaviour of some biodegradable micropollutants compared to the SBF system, the influence of redox conditions and microbial community was observed. An advantage of the SAT system over the SBF system was found in the sorption capacity of the natural soil. Especially positively charged micropollutants showed attenuation due to ionic interactions with negatively charged soil particles. Based on the physicochemical properties at ambient pH, the degree of removal in the investigated systems and the occurrence in the source water, a selection of process-based indicator substances was proposed.
Within the first two parts of this thesis a micropollutant was frequently detected at elevated concentrations in WWTPs effluents, which was not previously in the focus of environmental research: the antidiabetic drug sitagliptin (STG). STG showed low degradability in biological systems and thus it was investigated to what extend chemical treatment by ozonation can ensure attenuation of it. STG contains an aliphatic primary amine as the principal point of attack for the ozone molecule. There is only limited information about the behaviour of this functional group during ozonation and thus, STG served as an example for other micropollutants containing aliphatic primary amines. A pH-dependent degradation kinetic was observed due to the protonation of the primary amine at lower pH values. At pH values in the range 6 - 8, which is typical for the environment and in WWTPs, STG showed degradation kinetics in the range of 103 M-1s-1 and thus belongs to the group of readily degradable substances. However, complete degradation can only be expected at significantly higher pH values (> 9). The transformation of the primary amine moiety into a nitro group was observed as the major degradation mechanism for STG during ozonation. Other mechanisms involved the formation of a diketone, bond breakages and the formation of trifluoroacetic acid (TFA). Investigations at a pilot-scale ozonation plant using the effluent of a biological degradation of a municipal WWTP as source water confirmed the results of the laboratory studies: STG could not be removed completely even at high ozone doses and the nitro compound was formed as the main TP and remained stable during further ozonation and subsequent biological treatment. It can therefore be assumed that under realistic conditions both a residual concentration of STG and the formed main TP as well as other stable TPs such as TFA can be detected in the effluents of a WWTP consisting of conventional biological treatment followed by ozonation and subsequent biological polishing steps.
Enterprise Collaboration Systems (ECS) have become substantial for computer-mediated communication and collaboration among employees in organisations. As ECS combine features from social media and traditional groupware, a growing number of organisations implement ECS to facilitate collaboration among employees. Consequently, ECS form the core of the digital workplace. Thus, the activity logs of ECS are particularly valuable since they provide a unique opportunity for observing and analysing collaboration in the digital workplace.
Evidence from academia and practice demonstrates that there is no standardised approach for the analysis of ECS logs and that practitioners struggle with various barriers. Because current ECS analytics tools only provide basic features, academics and practitioners cannot leverage the full potential of the activity logs. As ECS activity logs are a valuable source for understanding collaboration in the digital workplace, new methods and metrics for their analysis are required. This dissertation develops Social Collaboration Analytics (SCA) as a method for measuring and analysing collaboration activities in ECS. To address the existing limitations in academia and practice and to contribute a method and structures for applying SCA in practice, this dissertation aims to answer two main research questions:
1. What are the current practices for measuring collaboration activities in Enterprise Collaboration Systems?
2. How can Social Collaboration Analytics be implemented in practice?
By answering the research questions, this dissertation seeks to (1) establish a broad thematic understanding of the research field of SCA and (2) to develop SCA as a structured method for analysing ac-tivity logs of ECS. As part of the first research question, this dissertation documents the status quo of SCA in the academic literature and practice. By answering the second research question, this dissertation contributes the SCA framework (SCAF), which guides the practical application of SCA. SCAF is the main contribution of this dissertation. The framework was developed based on findings from an analysis of 86 SCA studies, results from 6 focus groups and results from a survey among 27 ECS user companies. The phases of SCAF were derived from a comparison of established process models for data mining and business intelligence. The eight phases of the framework contain detailed descriptions, working steps, and guiding questions, which provide a step by step guide for the application of SCA in practice. Thus, academics and practitioners can benefit from using the framework.
The constant evaluation of the research outcomes in focus groups ensures both rigour and relevance. This dissertation employs a qualitative-dominant mixed-methods approach. As part of the university-industry collaboration initiative IndustryConnect, this research has access to more than 30 leading ECS user companies. Being built on a key case study and a series of advanced focus groups with representatives of user companies, this dissertation can draw from unique insights from practice as well as rich data with a longitudinal perspective.
Within the field of Business Process Management, business rules are commonly used to model company decision logic and govern allowed company behavior. An exemplary business rule in the financial sector could be for example:
”A customer with a mental condition is not creditworthy”. Business rules are
usually created and maintained collaboratively and over time. In this setting,
modelling errors can occur frequently. A challenging problem in this context is
that of inconsistency, i.e., contradictory rules which cannot hold at the same
time. For instance, regarding the exemplary rule above, an inconsistency would
arise if a (second) modeller entered an additional rule: ”A customer with a mental condition is always creditworthy”, as the two rules cannot hold at the same
time. In this thesis, we investigate how to handle such inconsistencies in business
rule bases. In particular, we develop methods and techniques for the detection,
analysis and resolution of inconsistencies in business rule bases
This thesis focuses on approximate inference in assumption-based argumentation frameworks. Argumentation provides a significant idea in the computerization of theoretical and practical reasoning in AI. And it has a close connection with AI, engaging in arguments to perform scientific reasoning. The fundamental approach in this field is abstract argumentation frameworks developed by Dung. Assumption-based argumentation can be regarded as an instance of abstract argumentation with structured arguments. When facing a large scale of data, a challenge of reasoning in assumption-based argumentation is how to construct arguments and resolve attacks over a given claim with minimal cost of computation and acceptable accuracy at the same time. This thesis proposes and investigates approximate methods that randomly select and construct samples of frameworks based on graphical dispute derivations to solve this problem. The presented approach aims to improve reasoning performance and get an acceptable trade-off between computational time and accuracy. The evaluation shows that for reasoning in assumption-based argumentation, in general, the running time is reduced with the cost of slightly low accuracy by randomly sampling and constructing inference rules for potential arguments over a query.
In this thesis, the performance of the IceCube projects photon propagation
code (clsim) is optimized. The process of GPU code analysis and perfor-
mance optimization is described in detail. When run on the same hard-
ware, the new version achieves a speedup of about 3x over the original
implementation. Comparing the unmodified code on hardware currently
used by IceCube (NVIDIA GTX 1080) against the optimized version run on
a recent GPU (NVIDIA A100) a speedup of about 9.23x is observed. All
changes made to the code are shown and their performance impact as well
as the implications for simulation accuracy are discussed individually.
The approach taken for optimization is then generalized into a recipe.
Programmers can use it as a guide, when approaching large and complex
GPU programs. In addition, the per warp job-queue, a design pattern used
for load balancing among threads in a CUDA thread block, is discussed in
detail.
Ray tracing acceleration through dedicated data structures has long been an important topic in computer graphics. In general, two different approaches are proposed: spatial and directional acceleration structures. The thesis at hand presents an innovative combined approach of these two areas, which enables a further acceleration of the tracing process of rays. State-of-the-art spatial data structures are used as base structures and enhanced by precomputed directional visibility information based on a sophisticated abstraction concept of shafts within an original structure, the Line Space.
In the course of the work, novel approaches for the precomputed visibility information are proposed: a binary value that indicates whether a shaft is empty or non-empty as well as a single candidate approximating the actual surface as a representative candidate. It is shown how the binary value is used in a simple but effective empty space skipping technique, which allows a performance gain in ray tracing of up to 40% compared to the pure base data structure, regardless of the spatial structure that is actually used. In addition, it is shown that this binary visibility information provides a fast technique for calculating soft shadows and ambient occlusion based on blocker approximations. Although the results contain a certain inaccuracy error, which is also presented and discussed, it is shown that a further tracing acceleration of up to 300% compared to the base structure is achieved. As an extension of this approach, the representative candidate precomputation is demonstrated, which is used to accelerate the indirect lighting computation, resulting in a significant performance gain at the expense of image errors. Finally, techniques based on two-stage structures and a usage heuristic are proposed and evaluated. These reduce memory consumption and approximation errors while maintaining the performance gain and also enabling further possibilities with object instancing and rigid transformations.
All performance and memory values as well as the approximation errors are measured, presented and discussed. Overall, the Line Space is shown to result in a considerate improvement in ray tracing performance at the cost of higher memory consumption and possible approximation errors. The presented findings thus demonstrate the capability of the combined approach and enable further possibilities for future work.
Scientific and public interest in epidemiology and mathematical modelling of disease spread has increased significantly due to the current COVID-19 pandemic. Political action is influenced by forecasts and evaluations of such models and the whole society is affected by the corresponding countermeasures for containment. But how are these models structured?
Which methods can be used to apply them to the respective regions, based on real data sets? These questions are certainly not new. Mathematical modelling in epidemiology using differential equations has been researched for quite some time now and can be carried out mainly by means of numerical computer simulations. These models are constantly being refinded and adapted to corresponding diseases. However, it should be noted that the more complex a model is, the more unknown parameters are included. A meaningful data adaptation thus becomes very diffcult. The goal of this thesis is to design applicable models using the examples of COVID-19 and dengue, to adapt them adequately to real data sets and thus to perform numerical simulations. For this purpose, first the mathematical foundations are presented and a theoretical outline of ordinary differential equations and optimization is provided. The parameter estimations shall be performed by means of adjoint functions. This procedure represents a combination of static and dynamical optimization. The objective function corresponds to a least squares method with L2 norm which depends on the searched parameters. This objective function is coupled to constraints in the form of ordinary differential equations and numerically minimized, using Pontryagin's maximum (minimum) principle and optimal control theory. In the case of dengue, due to the transmission path via mosquitoes, a model reduction of an SIRUV model to an SIR model with time-dependent transmission rate is performed by means of time-scale separation. The SIRUV model includes uninfected (U) and infected (V ) mosquito compartments in addition to the susceptible (S), infected (I) and recovered (R) human compartments, known from the SIR model. The unknwon parameters of the reduced SIR model are estimated using data sets from Colombo (Sri Lanka) and Jakarta (Indonesia). Based on this parameter estimation the predictive power of the model is checked and evaluated. In the case of Jakarta, the model is additionally provided with a mobility component between the individual city districts, based on commuter data. The transmission rates of the SIR models are also dependent on meteorological data as correlations between these and dengue outbreaks have been demonstrated in previous data analyses. For the modelling of COVID-19 we use several SEIRD models which in comparison to the SIR model also take into account the latency period and the number of deaths via exposed (E) and deaths (D) compartments. Based on these models a parameter estimation with adjoint functions is performed for the location Germany. This is possible because since the beginning of the pandemic, the cumulative number of infected persons and deaths
are published daily by Johns Hopkins University and the Robert-Koch-Institute. Here, a SEIRD model with a time delay regarding the deaths proves to be particularly suitable. In the next step, this model is used to compare the parameter estimation via adjoint functions with a Metropolis algorithm. Analytical effort, accuracy and calculation speed are taken into account. In all data fittings, one parameter each is determined to assess the estimated number of unreported cases.
Mathematical models of species dispersal and the resilience of metapopulations against habitat loss
(2021)
Habitat loss and fragmentation due to climate and land-use change are among the biggest threats to biodiversity, as the survival of species relies on suitable habitat area and the possibility to disperse between different patches of habitat. To predict and mitigate the effects of habitat loss, a better understanding of species dispersal is needed. Graph theory provides powerful tools to model metapopulations in changing landscapes with the help of habitat networks, where nodes represent habitat patches and links indicate the possible dispersal pathways between patches.
This thesis adapts tools from graph theory and optimisation to study species dispersal on habitat networks as well as the structure of habitat networks and the effects of habitat loss. In chapter 1, I will give an introduction to the thesis and the different topics presented in this thesis. Chapter 2 will then give a brief summary of tools used in the thesis.
In chapter 3, I present our model on possible range shifts for a generic species. Based on a graph-based dispersal model for a generic aquatic invertebrate with a terrestrial life stage, we developed an optimisation model that models dispersal directed to predefined habitat patches and yields a minimum time until these patches are colonised with respect to the given landscape structure and species dispersal capabilities. We created a time-expanded network based on the original habitat network and solved a mixed integer program to obtain the minimum colonisation time. The results provide maximum possible range shifts, and can be used to estimate how fast newly formed habitat patches can be colonised. Although being specific for this simulation model, the general idea of deriving a surrogate can in principle be adapted to other simulation models.
Next, in chapter 4, I present our model to evaluate the robustness of metapopulations. Based on a variety of habitat networks and different generic species characterised by their dispersal traits and habitat demands, we modeled the permanent loss of habitat patches and subsequent metapopulation dynamics. The results show that species with short dispersal ranges and high local-extinction risks are particularly vulnerable to the loss of habitat across all types of networks. On this basis, we then investigated how well different graph-theoretic metrics of habitat networks can serve as indicators of metapopulation robustness against habitat loss. We identified the clustering coefficient of a network as the only good proxy for metapopulation robustness across all types of species, networks, and habitat loss scenarios.
Finally, in chapter 5, I utilise the results obtained in chapter 4 to identify the areas in a network that should be improved in terms of restoration to maximise the metapopulation robustness under limited resources. More specifically, we exploit our findings that a network’s clustering coefficient is a good indicator for metapopulation robustness and develop two heuristics, a Greedy algorithm and a deducted Lazy Greedy algorithm, that aim at maximising the clustering coefficient of a network. Both algorithms can be applied to any network and are not specific to habitat networks only.
In chapter 6, I will summarize the main findings of this thesis, discuss their limitations and give an outlook of future research topics.
Overall this thesis develops frameworks to study the behaviour of habitat networks and introduces mathematical tools to ecology and thus narrows the gap between mathematics and ecology. While all models in this thesis were developed with a focus on aquatic invertebrates, they can easily be adapted to other metapopulations.
Graph-based data formats are flexible in representing data. In particular semantic data models, where the schema is part of the data, gained traction and commercial success in recent years. Semantic data models are also the basis for the Semantic Web - a Web of data governed by open standards in which computer programs can freely access the provided data. This thesis is concerned with the correctness of programs that access semantic data. While the flexibility of semantic data models is one of their biggest strengths, it can easily lead to programmers accidentally not accounting for unintuitive edge cases. Often, such exceptions surface during program execution as run-time errors or unintended side-effects. Depending on the exact condition, a program may run for a long time before the error occurs and the program crashes.
This thesis defines type systems that can detect and avoid such run-time errors based on schema languages available for the Semantic Web. In particular, this thesis uses the Web Ontology Language (OWL) and its theoretic underpinnings, i.e., description logics, as well as the Shapes Constraint Language (SHACL) to define type systems that provide type-safe data access to semantic data graphs. Providing a safe type system is an established methodology for proving the absence of run-time errors in programs without requiring execution. Both schema languages are based on possible world semantics but differ in the treatment of incomplete knowledge. While OWL allows for modelling incomplete knowledge through an open-world semantics, SHACL relies on a fixed domain and closed-world semantics. We provide the formal underpinnings for type systems based on each of the two schema languages. In particular, we base our notion of types on sets of values which allows us to specify a subtype relation based on subset semantics. In case of description logics, subsumption is a routine problem. For
the type system based on SHACL, we are able to translate it into a description
logic subsumption problem.
The sediments of surface waters are temporary or final depository of many chemical compounds, including trace metals and metalloids (metal(loid)s) from natural and anthropogenic sources. Whether they act as a source or sink of metal(loid)s depends strongly on the dynamics of the biogeochemical processes that take place at the sediment-water interface (SWI). Important information on biogeochemical processes as well as on the exposure, the fate and the transport of pollutants at the SWI can be obtained by determining chemical concentration profiles in the sediment pore water. A major challenge is to conduct experiments with a spatial resolution, which allows to adequately record existing gradients and to log all the parameters needed, to describe and better understand the complex processes at the SWIs. At the same time, it is from major importance to prevent the formation of any artifacts during sampling, which may occur due to the labile nature of the SWIs and the very steep biogeochemical gradients.
In this context, in the first part of this work, a system was developed and tested that enables the automated, minimal invasive sampling of sediment pore water of undisturbed or manipulated sediments while simultaneously recording parameters such as redox potential, oxygen content and pH value. In an incubation experiment the impact of acidification and mechanical disturbance (re-suspension) on the mobility of 13 metal(loid)s was investigated using a triple quadrupole inductively coupled plasma-mass spectrometry (ICP-QQQ-MS) multi-element approach. Most metals were released as consequence of sulfide weathering whereas mechanical disturbance had a major impact on the mobility of the oxide forming elements As, Mo, Sb, U and V. Additionally, options were demonstrated to address with the system the size fractionation of metal(loid)s in pore water samples and the speciation of As(III/V) and Sb(III/V).
In the second part, the focus, with a similar experimental design, was placed on the processes leading to the release of metal(loid)s. For this purpose, two incubation experiments with different oxygen supply were conducted in parallel. For the first time the nonmetals carbon, phosphorus and sulfur were analyzed simultaneous to 13 metal(loid)s in sediment pore water by ICP-QQQ-MS. Throughout the experiment metal(loid) size fractionation was monitored. It was confirmed that resuspension promotes the mobility of metalloids such as As, Sb and V, while the release of most metals was largely attributed to pyrite weathering. The colloidal (0.45-16 μm) contribution in terms of mobilization was only relevant for a few elements.
Finally, the sampling system was used as part of a new approach to sediment risk assessment. Undisturbed sediment cores from differently contaminated positions in the Trave estuary were examined, considering 16 metal(loid)s, the non-metals C, P and S and the ions NH4+, PO43- and SO42-. By the first in-depth comparison with in-situ dialysis-based pore water sampling the ability of the suction-based approach to represent field conditions was proven. The pore water studies together with supplementing resuspension experiments in bio-geochemical microcosms and sequential extraction identified the most “pristine” sediment of the study area as posing the greatest risk of metal(loid) release. However, the potentially released amounts per kg of sediment are only a few parts per thousand of the average daily loads of the Trave river.
Climate change is an existential threat to human survival, the social organization of society, and the stability of ecosystems. It is thereby profoundly frightening. In the face of threat, people often want to protect themselves instead of engaging in mitigating behaviors. When psychological resources are insufficient to cope, people often respond with different forms of denial. In this dissertation, I contribute original knowledge to the understanding of the multifaceted phenomenon of climate denial from a psychological perspective.
There are four major gaps in the literature on climate denial: First, the spectrum of climate denial as a self-protective response to the climate crisis has not received attention within psychology. Second, basic psychological need satisfaction, a fundamental indicator of human functioning and the ability to cope with threat, has not been investigated as a predictor of climate denial. Third, relations of the spectrum of climate denial to climate-relevant emotions, specifically climate anxiety, have not been examined empirically. Forth, it has not been investigated how the spectrum of climate denial relates to established predictors of climate denial, namely right-wing ideological convictions and male gender. To address those gaps, I investigate what the spectrum of climate denial looks like in the German context and how it relates to basic psychological need satisfaction and frustration, pro-environmental behavior, climate anxiety, ideological conviction, and gender.
Five manuscripts reveal that climate denial exists on a spectrum in the German context, ranging from the distortion of facts (interpretive climate denial, specifically denial of personal and global outcome severity) to the denial of the implications of climate change (implicatory climate denial, specifically avoidance, denial of guilt, and rationalization of one's own involvement). Across analyses, low basic psychological need satisfaction predicted the spectrum of climate denial, which was negatively related to pro-environmental behavior. Climate denial was generally negatively related to climate anxiety, except for a positive association of avoidance and climate anxiety. Right-wing ideological conviction was the strongest predictor of climate denial across the spectrum. However, low need satisfaction and male gender were additional weaker predictors of implicatory climate denial.
These findings suggest that the spectrum of climate denial serves many psychological functions. Climate denial is possibly both a self-protective strategy to downregulate emotions and to protect oneself from loss of privilege. In short, it represents a barrier to climate action that may only be resolved once people have sufficient psychological resources to face the threat of climate change and cope with their underlying self-protective, emotional responses.
Human population pressure increased with the population growth around the NNP and Cyamudongo with disturbance impacts on the forests isolating populations into fragments and today, Cyamudongo natural forest is located a way at a distance of at least 8.5 km horizontal distance to Nyungwe main block with a surface area estimated at 300 ha. Under Cyamudongo project implementation, there was a need to understand how the flora diversity responded to human imposed challenges and to forest restoration initiatives. Three physiognomic landscapes forest were identified and considered for three phases of vegetation survey in Cyamudongo and related to the closest area of Nyungwe main block. In this study, 15 transects were laid in each physiognomic forest landscape and 10 and 5 plots were set respectively in Cyamudongo and Gasumo study area. In total, 315 phytosociological relevés were performed and the Braun-Blanquet methods used for three times vegetation surveys. Species life-forms and chorophyte were evaluated and tree species dbh and height have been measured. Data were subjected to different statistical analyses using different softwares such as PAST, R 3.5.2, and SPSS. The mapping was done using Arc GIS and the Multi-Spectral Remote Sensing used to find NDVI for the vegetation classification.
NDVI trends showed that there has been fluctuations in vegetation classifications of the studied area. In this study, 494 vascular plant species from 106 families were harbored in the study area and distributed differently among forest landscapes and study phases. Although, 43.54% were common to Cyamudongo and Gasumo landscapes while 48.54 % of species diversity were hold only by Cyamudongo and 7.92% confined to Gasumo and 12 in total were found new records for Rwanda while several others suspected require detailed research for identification showing how the flora diversity of Cyamudongo is of special interest and extremely important for discoveries.
The finding of the study on diversity indices, the PCA, CA and the Cluster analysis, all statistical analyses (MANOVA, ANOVA) and life form spectra unanimously showed that the anthropogenic disturbance shaped the vegetation cover, the floristic composition, the species diversity, the forest landscapes community structure, the life form spectrum and the phytoclimate of Cyamudongo and Gasumo forest landscapes. Although, the vegetation analysis couldn’t clearly identify communities and sub-communities at the initial and final vegetation surveys and cluster groups were heterogeneous as well as overlapping and species associations not clearly defined due to the high level of similarities in species composition among forest landscapes and vegetation surveys. The species diversity was found high in secondary forest and Gasumo landscape forest and low in the primary forest and the buffer zone of Cyamudongo and the disturbance with gaps openings was found to be associated to the species diversity with a seasonal variation. The patterns of dbh for the buffer zone and of the size classes of all landscapes with an inverted ‘J’ indicated a healthy regeneration in the forest landscapes and tree species explained a good regeneration and recruitment capacity. Different shapes in the pattern of dbh with respectively an inverted ‘J’, ‘J ‘and ‘U’ for the buffer zone, primary and together the secondary and Gasumo forest landscapes indicated differences in the landscapes health and degree of regeneration and recruitment capacity.
Findings from differents measuements showed at which extend human activities have shaped the flora diversity and structure of forest landcapes studied. For instance, disturbances due human activities were daily oberved and trees were logged by neighboring communities such as Batwa populations at Cyamudongo and local populations at Gasumo. Some species were evenly observed targeted for their barks such as Ocotea usambarensis, Parinari excelsa for medicines and many others for their wood quality, fire wood collection and for agricultural purposes.
In the period of Cyamudongo project implementation, important achievements included the increase of forest biomass and therefore the photosynthetic capacity and the evapotranspiration potential that influence the rainfall regime; the regulation of weather conditions and then species diversity; supporting local communities and limiting human activities; raising awareness on conservation and protection of biodiversity and improving of living conditions of neighboring populations by providing paid employment and so to restore to the Cyamudongo forest ecosystem functions. Moreover, Cyamudongo forest remains vulnerable as surrounded by local communities with a high population pressure relying on forest resources for its survival. Cyamudongo harbors a high level of endemism and is a small hotspot for biodiversity conservation. It is therefore recommended to strengthen conservation and protection measures and continue the support of local communities.
Over the past few decades, Single-Particle Analysis (SPA), in combination with cryo-transmission electron microscopy, has evolved into one of the leading technologies for structural analysis of biological macromolecules. It allows the investigation of biological structures in a close to native state at the molecular level. Within the last five years the achievable resolution of SPA surpassed 2°A and is now approaching atomic resolution, which so far has only been possible with Xray crystallography in a far from native environment. One remaining problem of Cryo-Electron Microscopy (cryo-EM) is the weak image contrast. Since the introduction of cryo-EM in the 1980s phase plates have been investigated as a potential tool to overcome these contrast limitations. Until now, technical problems and instrumental deficiencies have made the use of phase plates difficult; an automated workflow, crucial for the acquisition of 1000s of micrographs needed for SPA, was not possible. In this thesis, a new Zernike-type Phase Plate (PP) was developed and investigated. Freestanding metal films were used as a PP material to overcome the ageing and contamination problems of standard carbon-based PPs. Several experiments, evaluating and testing various metals, ended with iridium as the best-suited material. A thorough investigation of the properties of iridium PP followed in the second part of this thesis. One key outcome is a new operation mode, the rocking PP. By using this rocking-mode, fringing artifacts, another obstacle of Zernike PPs, could be solved. In the last part of this work, acquisition and reconstruction of SPA data of apoferritin was performed using the iridium PP in rocking-mode. A special semi-automated workflow for the acquisition of PP data was developed and tested. The recorded PP data was compared to an additional reference dataset without a PP, acquired following a conventional workflow.
The protected areas of Rwanda are facing various challenges resulting from the anthropogenic activities of the surrounding communities especially in the adjacent area to Cyamudongo isolated rain forest, which results in climate change, soil degradation, and loss of biodiversity. Therefore, this study aims to broaden current knowledge on the impact of sustainable Agroforestry (AF) on the Carbon (C) stock and Biodiversity conservation on the surroundings of Cyamudongo isolated rain forest and Ruhande Arboretum.
To understand this, the permanent sample plots (PSPs) were established mainly in the designed four transects of four km long originating on the boundary of the Cyamudongo isolated rain forest following the slope gradient ranging from 1286 to 2015 m asl. A total number of 73 PSPs were established in the Cyamudongo study area while 3 PSPs were established in the Ruhande AF plot. The Arc Map GIS 10.4 was used to design and map the sampling areas while GPS was used for localization of collected items. Statistical significance was analyzed through the R-software especially for wood and soil variables while for biodiversity indicator species, MVSP Software 3.0 was used to determine the Shannon Diversity indices and similarities among species.
In this study, I have obtained comprehensive results demonstrating that in all study areas, the various AF tree species contribute differently to C stock and C sequestration and the amount of C stored and removed from the atmosphere depends on different factors such as tree species, plantation density, growth stage, or the age of establishment, applied management practices, wood specific density (WSD), wood C concentration, and climatic conditions. The estimated quantity of sequestrated C for 2 years and 34 years AF species were 13.11 t C ha -1 yr-1 (equivalent to 48 t CO2 ha -1 yr-1) and 6.85 t ha-1 yr-1 (equivalent to 25.1 t CO2 ha -1 yr-1) in Cyamudongo and Ruhande respectively. The estimated quantity of C stored by the Ruhande AF plot is 232.94 t ha-1. In Cyamudongo, the overall C stored by the AF systems was 823 t ha-1 by both young tree species established by the Cyamudongo Project (35.84 t ha-1) and C stored by existed AF species before the existence of the Project (787.12 t ha-1). In all study areas, the Grevillea robusta was found to contribute more to overall stored C compared to other species under this study.
The tests revealed differences in terms of nutrient contents (C, N, C: N ratio, K, Na, Ca, and Mg) for various AF tree species of Cyamudongo and Ruhande study areas. The differences in terms of correlation for various variables of AF tree species in different study areas varied with tree species, age, stage of growth, and tree shape. By comparing the correlation coefficients for various tree variables for young and mature AF tree species, the results showed a high correlation variability for young species than mature or old species recorded in different environmental conditions of Cyamudongo and Ruhande study areas.
The recorded soil pH mean value across in Cyamudongo study area is 4.2, which is very strongly acidic. The tests revealed that the soil pH, C, C: N ratio, OM, NH4+, NO3-+NO2-, PO43-, and CEC were significantly (P < 0.05) different in various soil depths whereas the N was not statistically significant. The pH, N, C: N ratio, CEC, NH4+, PO43-, and Al3+ showed a significant difference across land uses whereas the C and NO3-+NO2- did not show any statistical difference. All tested chemical elements showed a statistical difference as far as altitude ranges are concerned. The only NH4+, PO43-, and CEC showed significant differences with time whereas all other remaining chemical elements did not show any statistical significance. The bulk density of soil was statistically different across land uses and altitude ranges. The soil pH was very strongly correlated with CEC, Mg, and Ca in cropland (CL) whereas it was strongly correlated in both AF and natural forest (NF) except for Mg, which was moderately correlated in AF. Furthermore, its correlation with K was strong in CL, moderate in AF while it was weak in NF. Finally, the pH correlation with Na was weak in both AF and CL whereas it was negligible in NF. The overall estimated soil C stock of the study area was 16848 t ha -1.
The sustainable AF practices changed significantly the frequency of reptiles, amphibians, and flowering plants while there was no statistical change observed on ferns with time. In terms of species richness, 16 flowering plants, 14 ferns, 5 amphibians, and 3 reptiles were recorded and monitored. These findings add to a growing body of literature on the impact of AF on the C stock, soil improvement, and Biodiversity. It is recommended that further researches should be undertaken for the contribution of other AF tree species to the C stock found in the agricultural landscape around all protected areas of Rwanda and the impact on them on the soil and biodiversity.
The stands surveyed are among the last closed canopy forests in Rwanda. Their exploration began in the early twentieth century and is still ongoing. Previous studies were mainly concerned with plant sociological issues and presented references to environmental factors in anecdotal form, at best using indirect ordination methods. The present study undertakes a classification of the vegetation with numerical methods and establishes quantitative relationships of the species’ distributional structure to environmental parameters using spatially explicit procedures. For this purpose, 94 samples were taken in 100 m² hexagonal plots. Of these, 70 samples are from Nyungwe, 14 are from Gishwati, and 10 are from Cyamudongo. Given the homogeneity of the terrain and vegetation, all vegetation types encountered, all types of stands, and all vegetation strata were included. The beta diversity is expressed by an average Bray-Curtis dissimilarity of 0.92, and in JOST’S (2007) numbers equivalents, 37.90 equally likely samples would be needed to represent the diversity encountered. Within the survey, 1198 species in 127 families were collected. Among the specimens are 6 local endemics and 40 Albertine Rift endemics. Resulting from UPGMA and FCM-NC, 20 to 40 plant communities were established depending on the level of resolution. It can be inferred by means of a Mantel correlogram that the mean zone of influence of a single vegetation stand, as sampled by a 100 m² plot in Nyungwe Forest, ranges between 0.016 and 3.42 km. Of the communities compiled using FCM-NC and UPGMA, 50% consist of individual samples. Beyond undersampling, natural small-scale discontinuities are reflected by this result. Partial db-RDA resulted in an explained variation of 9.60% and 14.41% for environmental and soil factors, respectively. Utilising variation partitioning analyses based on CCA and tb-RDA, between 21.70% and 37.80% of the variation in vegetation data could be explained. The spatially structured fraction of these parameters accounts for between 30.50% and 49.80% of the explained variation (100%). The purely environmental parameters account for a share of 10.30% to 16.30%, whereby the lower limit originates from the unimodal approach and has lost its statistical significance. The soil variables, also after partial analysis, account for a share of 19.00% to 35.70%. While the residual impact of the climatic parameters is hardly significant, the effect of the soil properties is prevalent. In general, the spatially structured fraction of the parameters is predominant here. While on the broad-scale climatic factors, the altitude a.s.l. and the geology are determining factors, some soil parameters and matrix components also show their impacts here. In the mid-range of the scale, it is the forest matrix, the soil types, and the geology that determine species distribution. While in the fine range of the scale, some unrecorded parameters seem to have an effect, there are also neutral processes that determine species composition.
Content and Language Integrated Learning (CLIL) has experienced growing importance in the last decades and an increasing number of schools have already implemented CLIL programmes or are planning to do so. Though the potentials of CLIL programmes are widely praised, first research results also raise doubts if CLIL students can live up to these high expectations. Both Fehling (2005) as well as Rumlich (2013; 2016), for example, found that CLIL programmes not inevitably show the expected results but that the CLIL students’ success might also be at least partially explained by other influences, such as the selection process of future CLIL students. Hence, CLIL students apparently fall short of the high expectations that are usually connected to the respective CLIL programmes and as this is mainly based on the unsatisfactory quality of these programmes, Rumlich concludes that “it is now high time to focus on the quality of CLIL provision” (Rumlich 2016: 452). He continues to explain that “the promises of CLIL do not materialise automatically owing to the fact that another language is used for learning in a non-language subject” (Rumlich 2016: 452). It must be assumed that the success of CLIL teaching also highly depends on the quality of the CLIL teachers.
In contrast to the continuously growing number of CLIL schools, however, the number of specifically trained CLIL teachers is comparably small. In Germany, CLIL teachers are not (yet) required to attend any special training in order to teach in a CLIL programme. Notwithstanding, is it sufficient for a CLIL teacher only to be trained in the content subject and the foreign language? Or does CLIL teaching require more than the sum of these two components? Do CLIL teachers need additional teaching competences to the ones of a content and a language teacher? In the light of the recent findings of CLIL programmes falling short of the high expectations, the answer to these questions must clearly be “Yes”. Hence, in order to appropriately train (future) CLIL teachers, special training programmes need to be developed which consider the teachers’ individual educational backgrounds, i.e. their qualifications as language and/or as content teachers and build up on these competences through adding the CLIL-specific teaching competences.
Therefore, this thesis aims at developing a German Framework for CLIL Teacher Education, which considers both the already published, theory-based standards of CLIL teacher education as well as the practical perspective of experienced CLIL teachers in Germany. This German Framework for CLIL Teacher Education classifies the different teaching competences, which are derived from integrating the theoretical and the practical perspective on CLIL teacher education, with regard to the three different competence areas, i.e. the general teaching competence, the language teaching competence and the subject teaching competence and is hence adaptable to different CLIL settings and educational backgrounds. In addition to developing this German Framework for CLIL Teacher Education, which provides the content of future CLIL teacher education programmes, this thesis discusses different forms of structurally implementing CLIL teacher education programmes in the existing structures of teacher education in Germany. This is achieved through analysing the current state of the art of CLIL teacher education at German universities and systematising the different forms of implementing these training programmes in the prevailing educational structures. Building on these first two steps, in the third and final step, this thesis develops a CLIL teacher education programme at a German university that is based on the results and elements of the German Framework for CLIL Teacher Education as well as the state of the art of CLIL teacher education in Germany. Thus, this thesis is allocated at the intersection between foreign language teaching as well as teacher education and is structured in eleven chapters.
Augmented reality (AR) applications typically extend the user's view of the real world with virtual objects.
In recent years, AR has gained increasing popularity and attention, which has led to improvements in the required technologies. AR has become available to almost everyone.
Researchers have made great progress towards the goal of believable AR, in which the real and virtual worlds are combined seamlessly.
They mainly focus on issues like tracking, display technologies and user interaction, and give little attention to visual and physical coherence when real and virtual objects are combined. For example, virtual objects should not only respond to the user's input; they should also interact with real objects. Generally, AR becomes more believable and realistic if virtual objects appear fixed or anchored in the real scene, appear indistinguishable from the real scene, and response to any changes within it.
This thesis examines on three challenges in the field of computer vision to meet the goal of a believable combined world in which virtual objects appear and behave like real objects.
Firstly, the thesis concentrates on the well-known tracking and registration problem. The tracking and registration challenge is discussed and an approach is presented to estimate the position and viewpoint of the user so that virtual objects appear fixed in the real world. Appearance-based line models, which keep only relevant edges for tracking purposes, enable absolute registration in the real world and provide robust tracking. On the one hand, there is no need to spend much time creating suitable models manually. On the other hand, the tracking can deal with changes within the object or the scene to be tracked. Experiments have shown that the use of appearance-based line models improves the robustness, accuracy and re-initialization speed of the tracking process.
Secondly, the thesis deals with the subject of reconstructing the surface of a real environment and presents an algorithm to optimize an ongoing surface reconstruction. A complete 3D surface reconstruction of the target scene
offers new possibilities for creating more realistic AR applications. Several interactions between real and virtual objects, such as collision and occlusions, can be handled with physical correctness. Whereas previous methods focused on improving surface reconstructions offline after a capturing step, the presented method de-noises, extends and fills holes during the capturing process. Thus, users can explore an unknown environment without any preparation tasks such as moving around and scanning the scene, and without having to deal with the underlying technology in advance. In experiments, the approach provided realistic results where known surfaces were extended and filled in plausibly for different surface types.
Finally, the thesis focuses on handling occlusions between the real and virtual worlds more realistically, by re-interpreting the occlusion challenge as an alpha matting problem. The presented method overcomes limitations in state-of-the-art methods by estimating a blending coefficient per pixel of the rendered virtual scene, instead of calculating only their visibility. In several experiments and comparisons with other methods, occlusion handling through alpha matting worked robustly and overcame limitations of low-cost sensor data; it also outperformed previous work in terms of quality, realism and practical applicability.
The method can deal with noisy depth data and yields realistic results in regions where foreground and background are not strictly separable (e.g. caused by fuzzy objects or motion blur).
Wild bees are essential for the pollination of wild and cultivated plants. However, within the
last decades, the increasing intensification of modern agriculture has led to both a reduction and fragmentation as well as a degradation of the habitats wild bees need. The resulting loss of pollinators and their pollination poses an immense challenge to global food production. To support wild bees, the availability of flowering resources is essential. However, the flowering period of each resource is temporally limited and has different effects on pollinators and their pollination, depending on the time of their flowering.
Therefore, to efficiently promote and manage wild bee pollinators in agricultural landscapes, we identified species-specific key floral resources of three selected wild bee species and their spatial and temporal availability (CHAPTERS 2, 3 & 4). We examined, which habitat types predominantly provide these resources (CHAPTERS 3 & 4). We also investigated whether floral resource maps based on the use of these key resources and their spatial and temporal availability explain the abundance and development of the selected wild bees (CHAPTERS 3 & 4) and pollination (CHAPTER 5) better than habitat maps, that only indirectly account for the availability of floral resources.
For each of the species studied, we were able to identify different key pollen sources, predominantly woody plants in the early season (April/May) and increasingly herbaceous plants in the later season (June/July; CHAPTERS 2, 3 & 4). The open woody semi-natural habitats of our agricultural landscapes provided about 75% of the floral resources for the buff-tailed bumblebees, 60% for the red mason bees, and 55% for the horned mason bees studied, although they accounted for only 3% of the area (CHAPTERS 3 & 4). In addition, fruit orchards provided about 35% of the floral resources for the horned mason bees on 4% of the landscape area (CHAPTER 3). We showed that both mason bee species benefited from the resource availability in the surrounding landscapes (CHAPTER 3). Yet this was not the case for the bumblebees (CHAPTER 4). Instead, the weight gain of their colonies, the number of developed queen cells and their colony survival were higher with increasing proximity to forests. The proximity to forests also had a positive effect on the mason bees studied (CHAPTER 3). In addition, the red mason bees benefited from herbaceous semi-natural habitats. The proportion of built-up areas had a negative effect on the horned mason bees, and the proportion of arable land on the red mason bees. The habitat maps explained horned mason bee abundances equally well as the floral resource maps, but red mason bee abundances were distinctly better explained by key floral resources. The pollination of field bean increased with higher proportions of early floral resources, whereas synchronous floral resources showed no measurable reduction in their pollination (CHAPTER 5). Habitat maps also explained field bean pollination better than floral resource maps. Here, pollination increased with increasing proportions of built-up areas in the landscapes and decreased with increasing proportions of arable land.
Our results highlight the importance of the spatio-temporal availability of certain key species as resource plants of wild bees in agricultural landscapes. They show that habitat maps are ahead of, or at least equal to, spatio-temporally resolved floral resource maps in predicting wild bee development and pollination. Nevertheless, floral resource maps allow us to draw more accurate conclusions between key floral resources and the organisms studied. The proximity to forest edges had a positive effect on each of the three wild bee species studied. However, besides pure food availability, other factors seem to co-determine the occurrence of wild bees in agricultural landscapes.
Efficient Cochlear Implant (CI) surgery requires prior knowledge of the cochlea’s size and its characteristics. This information helps to select suitable implants for different patients. Registered and fused images helps doctors by providing more informative image that takes advantages of different modalities. The cochlea’s small size and complex structure, in addition to the different resolutions and head positions during imaging, reveals a big challenge for the automated registration of the different image modalities. To obtain an automatic measurement of the cochlea length and the volume size, a segmentation method of cochlea medical images is needed. The goal of this dissertation is to introduce new practical and automatic algorithms for the human cochlea multi-modal 3D image registration, fusion, segmentation and analysis. Two novel methods for automatic cochlea image registration (ACIR) and automatic cochlea analysis (ACA) are introduced. The proposed methods crop the input images to the cochlea part and then align the cropped images to obtain the optimal transformation. After that, this transformation is used to align the original images. ACIR and ACA use Mattes mutual information as similarity metric, the adaptive stochastic gradient descent (ASGD) or the stochastic limited memory Broyden–Fletcher–Goldfarb–Shanno (s-LBFGS) optimizer to estimate the parameters of 3D rigid transform. The second stage of nonrigid registration estimates B-spline coefficients that are used in an atlas-model-based segmentation to extract cochlea scalae and the relative measurements of the input image. The image which has segmentation is aligned to the input image to obtain the non-rigid transformation. After that the segmentation of the first image, in addition to point-models are transformed to the input image. The detailed transformed segmentation provides the scala volume size. Using the transformed point-models, the A-value, the central scala lengths, the lateral and the organ of corti scala tympani lengths are computed. The methods have been tested using clinical 3D images of total 67 patients: from Germany (41 patients) and Egypt (26 patients). The atients are of different ages and gender. The number of images used in the experiments is 217, which are multi-modal 3D clinical images from CT, CBCT, and MRI scanners. The proposed methods are compared to the state of the arts ptimizers related medical image registration methods e.g. fast adaptive stochastic gradient descent (FASGD) and efficient preconditioned tochastic gradient descent (EPSGD). The comparison used the root mean squared distance (RMSE) between the ground truth landmarks and the resulted landmarks. The landmarks are located manually by two experts to represent the round window and the top of the cochlea. After obtaining the transformation using ACIR, the landmarks of the moving image are transformed using the resulted transformation and RMSE of the transformed landmarks, and at the same time the fixed image landmarks are computed. I also used the active length of the cochlea implant electrodes to compute the error aroused by the image artifact, and I found out an error ranged from 0.5 mm to 1.12 mm. ACIR method’s RMSE average was 0.36 mm with a standard deviation (SD) of 0.17 mm. The total time average required for registration of an image pair using ACIR was 4.62 seconds with SD of 1.19 seconds. All experiments are repeated 3 times for justifications. Comparing the RMSE of ACIR2017 and ACIR2020 using paired T-test shows no significant difference (p-value = 0.17). The total RMSE average of ACA method was 0.61 mm with a SD of 0.22 mm. The total time average required for analysing an image was 5.21 seconds with SD of 0.93 seconds. The statistical tests show that there is no difference between the results from automatic A-value method and the manual A-value method (p-value = 0.42). There is no difference also between length’s measurements of the left and the right ear sides (p-value > 0.16). Comparing the results from German and Egypt dataset shows there is no difference when using manual or automatic A-value methods (p-value > 0.20). However, there is a significant difference when using ACA2000 method between the German and the Egyptian results (p-value < 0.001). The average time to obtain the segmentation and all measurements was 5.21 second per image. The cochlea scala tympani volume size ranged from 38.98 mm3 to 57.67 mm3 . The combined scala media and scala vestibuli volume size ranged from 34.98 mm 3 to 49.3 mm 3 . The overall volume size of the cochlea should range from 73.96 mm 3 to 106.97 mm 3 . The lateral wall length of scala tympani ranged from 42.93 mm to 47.19 mm. The organ-of-Corti length of scala tympani ranged from 31.11 mm to 34.08 mm. Using the A-value method, the lateral length of scala tympani ranged from 36.69 mm to 45.91 mm. The organ-of-Corti length of scala tympani ranged from 29.12 mm to 39.05 mm. The length from ACA2020 method can be visualised and has a well-defined endpoints. The ACA2020 method works on different modalities and different images despite the noise level or the resolution. In the other hand, the A-value method works neither on MRI nor noisy images. Hence, ACA2020 method may provide more reliable and accurate measurement than the A-value method. The source-code and the datasets are made publicly available to help reproduction and validation of my result.
Despite the significant presence of neuroactive substances in the environment, bioassays that allow to detect diverse groups of neuroactive mechanisms of action are not well developed and not properly integrated into environmental monitoring and chemical regulation. Therefore, there is a need to develop testing methods which are amenable for fast and high-throughput neurotoxicity testing. The overall goal of this thesis work is to develop a test method for the toxicological characterization and screening of neuroactive substances and their mixtures which could be used for prospective and diagnostic hazard assessment.
In this thesis, the behavior of zebrafish embryos was explored as a promising tool to distinguish between different neuroactive mechanisms of action. Recently, new behavioral tests have been developed including photomotor response (PMR), locomotor response (LMR) and spontaneous tail coiling (STC) tests. However, the experimental parameters of these tests lack consistency in protocols such as exposure time, imaging time, age of exposure, endpoint parameter etc. To understand how experimental parameters may influence the toxicological interpretation of behavior tests, a systematic review of existing behavioral assays was conducted in Chapter 2. Results show that exposure concentration and exposure duration highly influenced the comparability between different test methods and the spontaneous tail coiling (STC) test was selected for further testing based on its relative higher sensitivity and capacity to detect neuroactive substances (Chapter 2).
STC is the first observable motor activity generated by the developing neural network of the embryo which is assumed to occur as a result of the innervation of the muscle by the primary motor neurons. Therefore, STC could be a useful endpoint to detect effect on the muscle innervation and also the on the whole nervous system. Consequently, important parameters of the STC test were optimized and an automated workflow to evaluate the STC with the open access software KNIME® was developed (Chapter 3).
To appropriately interpret the observed effect of a single chemical and especially mixture effects, requires the understanding of toxicokinetics and biotransformation. Most importantly, the biotransformation capacity of zebrafish embryos might be limited and this could be a challenge for assessment of chemicals such as organophosphates which require a bioactivation step to effectively inhibit the acetylcholinesterase (AChE) enzyme. Therefore, the influence of the potential limited biotransformation on the toxicity pathway of a typical organophosphate, chlorpyrifos, was investigated in Chapter 5. Chlorpyrifos could not inhibit AChE and this was attributed to possible lack of biotransformation in 24 hpf embryos (Chapter 5).
Since neuroactive substances occur in the environment as mixtures, it is therefore more realistic to assess their combined effect rather than individually. Therefore, mixture toxicity was predicted using the concentration addition and independent action models. Result shows that mixtures of neuroactive substances with different mechanisms of action but similar effects can be predicted with concentration addition and independent action (Chapter 4). Apart
from being able to predict the combined effect of neuroactive substances for prospective risk assessment, it is also important to assess in retrospect the combined neurotoxic effect of environmental samples since neuroactive substances are the largest group of chemicals occurring in the environment. In Chapter 6, the STC test was found to be capable of detecting neurotoxic effects of a wastewater effluent sample. Hence, the STC test is proposed as an effect based tool for monitoring environmental acute and neurotoxic effects.
Overall, this thesis shows the utility and versatility of zebrafish embryo behavior testing for screening neuroactive substances and this allows to propose its use for prospective and diagnostic hazard assessment. This will enhance the move away from expensive and demanding animal testing. The information contained in this thesis is of great potential to provide precautionary solutions, not only for the exposure of humans to neuroactive chemicals but for the environment at large.
The belief in a just world in face of injustice: victim, observer, and perpetrator perspectives
(2021)
Injustice happens every day either to us, to our neighbors, or people across the world. Yet, believing that the world is a fair place helps us to cope with this injustice and motivates us to behave fairly. Scholars have found that these functions that the belief in a just world (BJW) serves are crucial for maintaining mental health. However, the conditions under which BJW is functional and when people give up this belief are not well studied. The current dissertation aims to examine: when the BJW can be shattered, the role of the external world and other internal resources in face of injustice, and the role of BJW in predicting corrupt behavior. Three studies were conducted corresponding to each party of injustice: a victim, an observer, and a perpetrator.
Study 1 examined the effects of criminal victimization on BJW and buffering role of perceptions of justice in the criminal justice process. A cross-sectional study showed that victims of very severe crimes such as domestic violence and human trafficking had lower personal BJW than non-victims and victims of less severe crimes, and higher informational justice perceptions reduced the effect of victimization on the personal BJW. Study 2 aimed to test the changes in BJW after observing severe injustice. A longitudinal study showed that after observing school rampage attacks that happened at other schools, BJW of adolescent participants increased. Moreover, life satisfaction and perceived social support moderated the change of BJW. Study 3 examined relationships between BJW and corrupt behavior. A cross-sectional study showed that personal BJW can predict bribery behavior.
The findings of three studies provided evidence that BJW does not function in isolation. An external world and internal resources can reduce the threat of injustice on BJW. BJW plays an important role in predicting unfair behavior therefore authorities should aim to maintain the BJW of their citizens.
We are living in a world where environmental crises come to a head. To curb aggravation of these problems, a socio-ecological transformation within society is needed, going along with human behavior change. How to encourage such behavior changes on an individual level is the core issue of this dissertation. It takes a closer look at the role of individuals as consumers resulting in purchase decisions with more or less harmful impact on the environment. By using the example of plastic pollution, it takes up a current environmental problem and focuses on an understudied behavioral response to this problem, namely reduction behavior. More concrete, this dissertation examines which psychological factors can encourage the mitigation of plastic packaging consumption. Plastic packaging accounts for the biggest amount of current plastic production and is associated with products of daily relevance. Despite growing awareness of plastic pollution in society, behavioral responses do not follow accordingly and plastic consumption is still very high. As habits are often a pitfall when implementing more resource-saving behavior, this dissertation further examines if periods of discontinuity can open a ’window of opportunity’ to break old habits and facilitate behavior change. Four manuscripts approach this matter from the gross to the subtle. Starting with a literature review, a summary of 187 studies addresses the topic of plastic pollution and human behavior from a societal-scientific perspective. Based on this, a cross-sectional study (N = 648) examines the deter-minants of plastic-free behavior intentions in the private-sphere and public-sphere by structural equation modeling. Two experimental studies in pre-post design build upon this, by integrating the determinants in intervention studies. In addition, it was evaluated if the intervention presented during Lent (N = 140) or an action month of ‘Plastic Free July’ (N = 366) can create a ‘window of opportunity’ to mitigate plastic packaging consumption. The literature review emphasized the need for research on behavioral solutions to reduce plastic consumption. The empirical results revealed moral and control beliefs to be the main determinants of reduction behavior. Furthermore, the time point of an intervention influenced the likelihood to try out the new behavior. The studies gave first evidence that a ‘window of opportunity’ can facilitate change towards pro-environmental behavior within the application field of plastic consumption. Theoretical and practical implications of creating the right opportunity for individuals to contribute to a socio-ecological transformation are finally discussed.