The 10 most recently published documents
In this thesis the possibilities for real-time visualization of OpenVDB
files are investigated. The basics of OpenVDB, its possibilities, as well
as NanoVDB and its GPU port, were studied. A system was developed
using PNanoVDB, the graphics API port of OpenVDB. Techniques were
explored to improve and accelerate a single ray approach of ray tracing.
To prove real-time capability, two single scattering approaches were
also implemented. One of these was selected, further investigated and
optimized to achieve interactive real-time rendering.
It is important to give artists immediate feedback on their adjustments, as
well as the possibility to change all parameters to ensure a user friendly
creation process.
In addition to the optical rendering, corresponding benchmarks were
collected to compare different improvement approaches and to prove
their relevance. Attention was paid to the rendering times and memory
consumption on the GPU to ensure optimal use. A special focus, when
rendering OpenVDB files, was put on the integrability and extensibility of
the program to allow easy integration into an existing real-time renderer
like U-Render.
Semantic Web technologies have been recognized to be key for the integration of distributed and heterogeneous data sources on the Web, as they provide means to define typed links between resources in a dynamic manner and following the principles of dataspaces. The widespread adoption of these technologies in the last years led to a large volume and variety of data sets published as machine-readable RDF data, that once linked constitute the so-called Web of Data. Given the large scale of the data, these links are typically generated by computational methods that given a set of RDF data sets, analyze their content and identify the entities and schema elements that should be connected via the links. Analogously to any other kind of data, in order to be truly useful and ready to be consumed, links need to comply with the criteria of high quality data (e.g., syntactically and semantically accurate, consistent, up-to-date). Despite the progress in the field of machine learning, human intelligence is still essential in the quest for high quality links: humans can train algorithms by labeling reference examples, validate the output of algorithms to verify their performance on a data set basis, as well as augment the resulting set of links. Humans —especially expert humans, however, have limited availability. Hence, extending data quality management processes from data owners/publishers to a broader audience can significantly improve the data quality management life cycle.
Recent advances in human computation and peer-production technologies opened new avenues for human-machine data management techniques, allowing to involve non-experts in certain tasks and providing methods for cooperative approaches. The research work presented in this thesis takes advantage of such technologies and investigates human-machine methods that aim at facilitating link quality management in the Semantic Web. Firstly, and focusing on the dimension of link accuracy, a method for crowdsourcing ontology alignment is presented. This method, also applicable to entities, is implemented as a complement to automatic ontology alignment algorithms. Secondly, novel measures for the dimension of information gain facilitated by the links are introduced. These entropy-centric measures provide data managers with information about the extent the entities in the linked data set gain information in terms of entity description, connectivity and schema heterogeneity. Thirdly, taking Wikidata —the most successful case of a linked data set curated, linked and maintained by a community of humans and bots— as a case study, we apply descriptive and predictive data mining techniques to study participation inequality and user attrition. Our findings and method can help community managers make decisions on when/how to intervene with user retention plans. Lastly, an ontology to model the history of crowd contributions across marketplaces is presented. While the field of human-machine data management poses complex social and technical challenges, the work in this thesis aims to contribute to the development of this still emerging field.
Currently, there are a variety of digital tools in the humanities, such
as annotation, visualization, or analysis software, which support researchers in their work and offer them new opportunities to address different research questions. However, the use of these tools falls far
short of expectations. In this thesis, twelve improvement measures are
developed within the framework of a design science theory to counteract the lack of usage acceptance. By implementing the developed design science theory, software developers can increase the acceptance of their digital tools in the humanities context.
The presented study was motivated by the dynamic phenomena observed in basic catalytic surface reactions, especially by bi- and tristability, and the interactions between these stable states. In this regard, three reaction-diffusion models were developed and examined using bifurcation theory and numerical simulations.
A first model was designed to extend the bistable CO oxidation on Ir(111) to include hydrogen and its oxidation. The differential equation system was analyzed within the framework of bifurcation theory, revealing three branches of stable solutions.
One state is characterized by high formation rates (upper rate state, UR), while the other two branches display low formation rates (lower rate (LR) \& very low rate (VLR) states).
The overlapping branches form the shape of a `swallowtail', the curve of saddle-node bifurcations forming two cusps. Increasing the temperature leads to a subsequent unfolding and hence decreases the system complexity.
A series of numerical simulations representing possible experiments was conducted to illustrate the experimental accessibility (or the lack) of said states. Relaxation experiments show partially long decay times. Quasistatic scanning illustrates the existence of all three states within the tristable regime and their respective conversion once crossing a fold.
A first attempt regarding the state dominance in reaction-diffusion fronts was done. While UR seems to dominate in 1D, a 2D time-evolution shows that LR invades the interphase between UR and VLR.
Subsequently, a generic monospecies mock model was used for the comprehensive study of reaction-diffusion fronts. A quintic polynomial as reaction term was chosen, derived by the sixth-order potential associated with the `butterfly bifurcation'. This ensures up to three stable solutions($u_{0}$,$u_{1}$,$u_{2}$), depending on the four-dimensional parameter space.
The model was explored extensively, identifying regions with similar behaviors.
A term for the front velocity connecting two stable states was derived, depending only on the relative difference of the states' potential wells.
Equipotential curves were found, where the front velocity vanishes of a given front. Numerical simulations on a two-dimensional, finite disk using a triangulated mesh supported these findings.
Additionally, the front-splitting instability was observed for certain parameters. The front solution $u_{02}$ becomes unstable and divides into $u_{01}$ and $u_{12}$, exhibiting different front velocities. A good estimate for the limit of the front splitting region was given and tested using time evolutions.
Finally, the established mock model was modified from continuous to discrete space, utilizing a simple domain in 1D and three different lattices in 2D (square, hexagonal, triangular).
For low diffusivities or large distances between coupling nodes, fronts can become pinned, if the parameters are within range of the equipotential lines. This phenomenon is known as propagation failure and its extent in parameter space was explored in 1D. In 2D, an estimate was given for remarkable front orientations respective to the lattice using a pseudo-2D approximation. Near the pinning region, front velocities differ significantly from the continuous expectation as the shape of the curve potential becomes significant. Factors that decide the size and shape of the pinning regions are the coupling strength, the lattice, the front orientation relative to the lattice, and the front itself. The bifurcation diagram shows a snaking curve in the pinning region, each alternating branch representing a stable or unstable frozen front solution. Numerical simulations supported the observations concerning propagation failure and lattice dependence.
Furthermore, the influence of front orientation on the front velocity was explored in greater detail, showing that fronts with certain lattice-dependent orientations are more or less prone to propagation failure. This leads to the possibility of pattern formation, reflecting the lattice geometry. An attempt to quantify the front movement depending on angular front orientation has shown reasonable results and good agreement with the pseudo-2D approach.
Die Studie thematisiert die Positionierung und Subjektivierung von Medienpädagog*innen im Diskurs um Gewaltdarstellungen in Computerspielen. Der sogenannte ‚Killerspiel‘-Diskurs in den Jahren 2001 bis 2016 stellt für medienpädagogische Fachkräfte ein Feld widersprüchlicher Handlungserwartungen dar, Gewaltdarstellungen in Computerspielen entweder als Problem wahrzunehmen und dieses zu bearbeiten oder Computerspiele als Chance zu begreifen. Als rele-vante Multiplikator*innen diskursiver Wissensbestände wurden deswegen für diese Studie Me-dienpädagog*innen interviewt, die an maßgeblichen Positionen in der Schnittstelle zwischen Wissenschaft und Praxis agieren und daher für viele Kolleg*innen deutungs- und praxisrelevan-tes Wissen generieren. Um die Ausrichtung dieses Wissens zu prüfen, wurde in dieser Studie die Frage gestellt, wie sich diese medienpädagogischen Fachkräfte, die korrigierend in Diskurse ein-greifen, positionieren und inwiefern (medien-)pädagogische Professionalität als Ressource und Grenze der Positionierung fungiert.
Um die Fragestellung zu beantworten wurden zwei empirisch analytische Untersuchungen durchgeführt. Zuerst wurde eine Sekundäranalyse bestehender Diskursanalysen zum ‚Killer-spiel‘-Diskurs durchgeführt, um die Subjektpositionen herauszuarbeiten, mit denen sich die Me-dienpädagog*innen auseinandersetzen mussten. In einem zweiten Schritt wurde eine qualitative Interviewstudie mit neun Medienpädagog*innen durchgeführt. Im Anschluss an die semi-narrativen Expert*inneninterviews wurden diese in einem dreistufigen Verfahren ausgewertet. Nach der deduktiven und induktiven Kategorienbildung in Anlehnung an die inhaltlich struktu-rierende Inhaltsanalyse, wurde im Rahmen einer Deutungsmusteranalyse das Deutungswissen der Medienpädagog*innen und der Sinnhorizont ihrer Intervention in den Diskurs feinanalytisch rekonstruiert. Zuletzt wurden drei biographische Fallanalysen durchgeführt, um die Relationie-rung zwischen Diskurs und (Berufs-)biographie zu diskutieren.
Im Rahmen der Sekundäranalyse des ‚Killerspiel‘-Diskurses konnte die bisher in Diskursanaly-sen rekonstruierte Differenzierung von Risiko- und Chancennarrativ erweitert werden. Durch die Abgrenzung jeweils zweier Deutungsmuster des Problemdiskurses (‚Gefahr‘ und ‚Risiko‘) und des Gegendiskurses (‚Optimierung von Lernchancen‘ und ‚Kultur‘) konnten dadurch Positionie-rungen in multiplen Konfliktfeldern sichtbar gemacht werden. So war es möglich die fachliche Positionierung der Medienpädagog*innen als Zwischenraum zu fassen, in dem sowohl Deutun-gen des Gegendiskurses als auch des Problemdiskurses eigenwillig miteinander relationiert wer-den. Die eigenwillige Aneignung diskursiver Problem- und Deutungsmuster verläuft bei den Medienpädagog*innen über unterschiedliche fachliche Schnittstellen und Kopplungen. Statt den Diskurs mit der eigenen Lebensgeschichte zu relationieren wird er mit der in Handlungsfeld-strukturen situierten fachlichen medienpädagogischen Praxis in Beziehung gesetzt. Dabei ist eine Pädagogisierung des Diskurses und eine Diskursivierung pädagogischer Handlungsfelder zu beobachten. Mittels mehrerer Pädagogiken werden diskursive Deutungsmuster transformiert und das medienpädagogische Handeln durch die Re-Interpretation medienpädagogischer Hand-lungsfelder im Sinnhorizont des Diskurses als Intervention in den Diskurs gerahmt. Gleichzeitig wird in einem ‚Opportunismus der Uneindeutigkeit‘ die Anschlussfähigkeit an Problemdeutun-gen durch die Selbstdarstellung als verantwortliche Problembearbeiter*innen gewahrt, wodurch die eigene Handlungsfähigkeit, die Legitimität des Handelns und der Zugang zu gesellschaftli-chen Ressourcen gesichert wird.
In den Fallanalysen zeigte sich, dass diese fachlichen Positionierungen nur dann einen Subjekti-vierungsprozess dokumentieren, wenn die Erzählbausteine des Diskurses (Deutungsmuster und diskursiver Konflikt) als Material für die eigene Selbsterzählung herangezogen und als Professi-onsverständnis re-artikuliert werden. Das Konfliktszenario wird dann über dessen öffentliche Thematisierung hinaus als berufsbiographisches Projekt formulierbar, was sich insbesondere da-rin zeigt, dass prospektive Zukunftsentwürfe weiterhin im Deutungs- und Konfliktspektrum des Diskurses verortet werden. Subjektivierung professioneller Akteure kann daher als über fachliche Positionierungen (als fachlich orientierte, kommentierende Auseinandersetzungen mit im Diskurs verhandelten Deutungsmustern und Wissensbeständen) hinausgehende Prozesse der Deutung des eigenen Professionalitätsverständnisses, die Ausbildung von Pädagogiken und die Veranke-rung berufsbiographischer Ziele im Horizont des Deutungsspektrum des Diskurses gefasst wer-den.
In der medienpädagogischen Professionsforschung können die Deutungsmuster und Subjektpo-sitionen des Diskurses als Professionalitätserwartungen analytisch Anwendung finden. Ihr Vor-teil gegenüber den hierfür auch herangezogenen Paradigmen der Medienpädagogik ist der Aktu-alitäts- und Gegenstandsbezug. Auch in anderen Themenbereichen (bspw. Mediensucht) können die Deutungsmuster des Diskurses sinnvoll Anwendung finden. Die Studie konnte zudem zei-gen, dass eine Subjektivierungsheuristik sinnvoll auf professionelle Akteure anwendbar ist, da fachliche Positionierungen von Subjektivierungen deutlich unterschieden werden können. Dafür wurde eine spezielle für professionelle Akteure konzipierte Subjektivierungsheuristik entworfen, die insbesondere den unterschiedlichen Funktionen diverser Wissensformen Rechnung tragen kann und in der Professionsforschung die Relevanz des diskursiven Wissens als relevanter Wis-sensform für professionelle Praxis herausstellt.
The growing numbers of breeding rooks (Corvus frugilegus) in the city of Landau (Rhineland- Palatinate, Germany) increase the potential for conflict between rooks and humans, which is mainly associated with noise and faeces. Therefore, the aim of this work is a better understanding of the breeding tree selection of the rook in order to develop options for action and management in the future.
Part I of this thesis provides general background information on the rook and includes mapping of the rookeries in the Anterior Palatinate and South Palatinate including Landau in the year 2020. That mapping revealed that the number of rural colonies has decreased, while the number of urban colonies has increased in the study area in the last few years. In line with current literature, tree species and tree size were important criteria for breeding tree selection. However, the mapping showed that additional factors must be important as well.
Therefore, as rooks seem to often breed along traffic axes, Part II of this thesis examines how temperature, artificial light and noise, which are all linked to traffic axes, affect the breeding tree selection of the rook in the city of Landau. The following three hypotheses are developed: (1) manually selected breeding trees (Bm) have a warmer microclimate than manually selected non-breeding trees (Nm) or randomly selected non-breeding trees (Nr), (2) Bm are exposed to a higher light level than Nm or Nr and (3) Bm are exposed to a higher noise level than Nm or Nr. To test these hypotheses, 15 Bm, 13 Nm and 16 Nr are investigated.
The results show that Bm were exposed to more noise than both types of non-breeding trees (μBm, noise = 36.52481 dB, μNm, noise = 31.27229 dB, μNr, noise = 29.17417 dB) where the difference between Bm and Nr was significant. In addition, there was a tendency for Bm to be exposed to less light (μBm, light = 0.356 lx) than Nm (μNm, light = 0.4107692 lx) and significantly less light than Nr (μNr, light = 1.995 lx), while temperature did not differ between the groups (μBm, temp = 16.90549 °C, μNm, temp = 16.93118 °C, μNr, temp = 17.28639 °C).
This study shows for the first time that rooks prefer trees which are exposed to low light levels and high noise levels, i.e. more intense traffic noise, for breeding. It can only be speculated that the cause of this is lower enemy pressure at such sites. The fact that temperature does not seem to have any influence on breeding tree selection may be due to only small temperature differences at nest height, which might be compensated by breeding behaviour. Consequently, in the long term one management approach could be to divert traffic from inner-city areas, especially schools and hospitals, to bypasses. If tree genera suitable for rooks, such as plane trees, are planted along the bypasses, those sites could provide suitable alternative habitats to inner-city breeding locations, which become less attractive for breeding due to noise reduction. In the short term in addition to locally implemented repellent measures the most effective approach is to strengthen rook acceptance among the population. However, further research is needed to verify the results of this thesis and to gain further insights into rook breeding site selection in order to develop effective management measures.
Background. Agricultural plastic mulches offer great benefits such as higher yields and lower pesticide use. Yet, plastic mulches may disintegrate over time and fragment into smaller debris. Such plastic debris is expected to remain in the field after removal of the plastic mulch and thus contributes to soil contamination with plastics.
Method. To investigate this, we collected soil samples at 0–10 cm and 10–40 cm depth from three fields covered with black mulch film for three consecutive years. Three fields without any reported plastic use served as control. Visual plastic debris > 1 cm (macroplastics) was collected from the soil surface. Mesoplastics between 2 mm and 1 cm were density separated from the sampled soil using saturated NaCl solution and analyzed by Fourier-transform infrared spectroscopy. Debris ≤ 2 mm (microplastics) was dispersed from 50 g soil using sodium hexametaphosphate solution followed by the aforementioned density separation. The separated polyethylene (PE), polypropylene (PP), and polystyrene (PS) were quantified via solvent-based pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS).
Results. With 89–206 fragments ha−1, the majority of macroplastics were located in fields previously covered with mulch films. 80% of the collected specimen were identified as black PE film. The number of mesoplastics in plastic-mulched soil was 2.3 particles kg−1, while only 1.0 particles kg−1 were found in the reference fields. Py–GC/MS revealed microplastic levels of up to 13 mg kg−1. The PE content was significantly higher in plastic-mulched fields than in reference fields.
Discussion. Although the identified plastic levels are lower than those reported in comparable studies, our results still suggest that plastic mulching functions as a source of plastic debris in agricultural systems. Due to its severely restricted degradability, these plastics are likely to accumulate in soil in the long term and further fragment into smaller and smaller debris.
The application of artificial intelligences on digital games became more and more successful in recent years. A drawback is, that they need lots of computing power to achieve good results, the more complex the game, the more computing power is needed. In this thesis a strategy learning-system is implemented, which is based on crowd-learned heuristics. The heuristics are given in a wiki. The research is done according to the Design Science Research Methodology. The implemented system is allied to the game Dominion. To do this, an ontology for Dominion is designed. A mapping language is defined and implemented in the system, which allows the mapping of information in the wiki to an ontology. Furthermore, metrics to rate the found strategies are defined. Using the system, users can enter a mapping for the information transfer and apply it. They can also select cards from Dominion, for which the system determines and rates strategies. Finally, the system is evaluated by Dominion-players by rating the strategies, which are found by the system, and the defined metrics.
Fünfundzwanzigste Ordnung zur Änderung der Ordnung für die Prüfung im lehramtsbezogenen Zertifikatsstudiengang (Erweiterungsprüfung) an der Universität Koblenz-Landau und der Hochschule Koblenz
Satzung über die Leitung und die innere Struktur wissenschaftlicher Einrichtungen und Betriebseinheiten der Universität Koblenz
Satzung zur Festsetzung der Normwerte für den Ausbildungsaufwand (Curricularnormwerte) der Universität Koblenz-Landau – Campus Koblenz
Satzung zur Festsetzung von Zulassungszahlen an der Universität Koblenz-Landau – Campus Koblenz für das Studienjahr 2022/2023
Satzung zur Festsetzung der Normwerte für den Ausbildungsaufwand (Curricularnormwerte) der Universität Koblenz-Landau – Campus Landau
Satzung zur Festsetzung von Zulassungszahlen an der Universität Koblenz-Landau – Campus Landau für das Studienjahr 2022/2023
Wahlordnung für die Wahlen der Organe der Rheinland-Pfälzischen Technischen Universität Kaiserslautern-Landau
Grundordnung der Rheinland-Pfälzischen Technischen Universität Kaiserslautern-Landau
Zehnte Ordnung zur Änderung der Ordnung für die Prüfung im Bachelorstudiengang Umweltwissenschaften und in den Masterstudiengängen Umweltwissenschaften / Environmental Sciences und Ecotoxicology (Environmental Pollution Management) an der Universität Koblenz-Landau, Campus Landau
Agricultural intensification is leading to a severe decline in farmland biodiversity worldwide. The resulting landscape simplification through the expansion of monocultures and removal of non-crop habitats has a major impact on arthropod communities in agricultural landscapes. While arable fields are often highly disturbed and ephemeral habitats that are unsuitable for many species, non-crop habitats in agroecosystems can provide important refugia. The creation of non-crop habitats through agri-environmental schemes (AES) in intensive agricultural landscapes, such as the ‘Maifeld’ region in western Germany, is intended to mitigate the negative effects of agricultural intensification, although the effectiveness of these measures for nature conservation is still controversial. Therefore, this work focuses on the taxonomic and functional diversity of beetles (Coleoptera) and spiders (Araneida), being important providers of ecosystem services, between wheat fields and different non-crop habitats, namely grassy field margins adjacent to wheat and oilseed rape fields, small- and large-scale set-aside areas sown with wildflowers, and permanent grassland fallows. Arthropods were collected between 2019 and 2020 using pitfall traps and suction sampling. Land-use type influenced beetle and spider diversity in the study area, with significantly higher values in grassland fallows than wheat fields. Surprisingly, species diversity differed little among all non-crop habitats, but all harboured distinct species assemblages. In particular, large long-term grassland fallows showed the largest within-group variation of beetle and spider assemblages and represented important habitats, especially for habitat specialists and threatened species, likely due to their variable soil moisture and complex habitat structure. In contrast, the homogeneous arthropod assemblages of wheat fields exhibited lower trait richness and were dominated by a few predatory species adapted to such disturbed, man-made habitats. Interestingly, all conservation measures complemented each other in that they contributed in different ways to supporting beetles and spiders in agricultural landscapes. Even small-scale non-crop habitats and existing habitat boundaries in an agricultural matrix appear to be valuable habitats for farmland arthropods by enhancing taxonomic diversity. Field margins and small wildflower-sown patches can link isolated non-crop habitats and contribute to a heterogeneous agricultural landscape. Consequently, a combination of various small- and large-scale greening measures leads to increased compositional and configurational landscape heterogeneity, resulting in improved beetle and spider diversity. Considering the ongoing loss of farmland biodiversity worldwide, agri-environmental schemes should be promoted in the future, as they are particularly important for arthropod conservation in intensive agricultural landscapes such as the Maifeld region.
