OPUS 4 | Search

Integrated Mobile Visualization and Interaction of Events and POIs (2010)

Schmeiß, Daniel ; Scherp, Ansgar ; Staab, Steffen

We propose a new approach for mobile visualization and interaction of temporal information by integrating support for time with today's most prevalent visualization of spatial information, the map. Our approach allows for an easy and precise selection of the time that is of interest and provides immediate feedback to the users when interacting with it. It has been developed in an evolutionary process gaining formative feedback from end users.

Designing Core Ontologies (2011)

Scherp, Ansgar ; Saathoff, Carsten ; Franz, Thomas ; Staab, Steffen

One of the key factors that hinders integration of distributed, heterogeneous information systems is the lack of a formal basis for modeling the complex, structured knowledge that is to be exchanged. To alleviate this situation, we present an approach based on core ontologies. Core ontologies are characterized by a high degree of axiomatization and formal precision. This is achieved by basing on a foundational ontology. In addition, core ontologies should follow a pattern-oriented design approach. By this, they are modular and extensible. Core ontologies allow for reusing the structured knowledge they define as well as integrating existing domainrnknowledge. The structured knowledge of the core ontologies is clearly separated from the domain-specific knowledge. Such core ontologies allow for both formally conceptualize their particular fields and to be flexibly combined to cover the needsrnof concrete, complex application domains. Over the last years, we have developed three independent core ontologies for events and objects, multimedia annotations, and personal information management. In this paper, we present the simultaneousrnuse and integration of our core ontologies at the example of a complex, distributed socio-technical system of emergency response. We describe our design approach for core ontologies and discuss the lessons learned in designing them. Finally, we elaborate on the beauty aspects of our core ontologies.

Explicit and Implicit Schema Information on the Linked Open Data Cloud: Joined Forces or Antagonists? (2012)

Scherp, Ansgar ; Gottron, Thomas ; Knauf, Malte ; Scheglmann, Stefan

Schema information about resources in the Linked Open Data (LOD) cloud can be provided in a twofold way: it can be explicitly defined by attaching RDF types to the resources. Or it is provided implicitly via the definition of the resources´ properties. In this paper, we analyze the correlation between the two sources of schema information. To this end, we have extracted schema information regarding the types and properties defined in two datasets of different size. One dataset is a LOD crawl from TimBL- FOAF profile (11 Mio. triple) and the second is an extract from the Billion Triples Challenge 2011 dataset (500 Mio. triple). We have conducted an in depth analysis and have computed various entropy measures as well as the mutual information encoded in this two manifestations of schema information. Our analysis provides insights into the information encoded in the different schema characteristics. It shows that a schema based on either types or properties alone will capture only about 75% of the information contained in the data. From these observations, we derive conclusions about the design of future schemas for LOD.

A model of events based on a foundational ontology (2009)

Scherp, Ansgar ; Franz, Thomas ; Saathoff, Carsten ; Staab, Steffen

The lack of a formal event model hinders interoperability in distributed event-based systems. Consequently, we present in this paper a formal model of events, called F. The model bases on an upper-level ontology and pro-vides comprehensive support for all aspects of events such as time and space, objects and persons involved, as well as the structural aspects, namely mereological, causal, and correlational relationships. The event model provides a flexible means for event composition, modeling of event causality and correlation, and allows for representing different interpretations of the same event. The foundational event model F is developed in a pattern-oriented approach, modularized in different ontologies, and can be easily extended by domain specifific ontologies.

Integrating Multimedia Metadata Standarts and Metadata Formats with the Multimedia Metadata Ontology: Method and Examples (2012)

Scherp, Ansgar ; Eißing, Daniel ; Saathoff, Carsten

The Multimedia Metadata Ontology (M3O) provides a generic modeling framework for representing multimedia metadata. It has been designed based on an analysis of existing metadata standards and metadata formats. The M3O abstracts from the existing metadata standards and formats and provides generic modeling solutions for annotations, decompositions, and provenance of metadata. Being a generic modeling framework, the M3O aims at integrating the existing metadata standards and metadata formats rather than replacing them. This is in particular useful as today's multimedia applications often need to combine and use more than one existing metadata standard or metadata format at the same time. However, applying and specializing the abstract and powerful M3O modeling framework in concrete application domains and integrating it with existing metadata formats and metadata standards is not always straightforward. Thus, we have developed a step-by-step alignment method that describes how to integrate existing multimedia metadata standards and metadata formats with the M3O in order to use them in a concrete application. We demonstrate our alignment method by integrating seven different existing metadata standards and metadata formats with the M3O and describe the experiences made during the integration process.

Networked RDF graphs (2007)

Schenk, Simon ; Staab, Steffen

Networked graphs are defined in this paper as a small syntactic extension of named graphs in RDF. They allow for the definition of a graph by explicitly listing triples as well as by SPARQL queries on one or multiple other graphs. By this extension it becomes possible to define a graph including a view onto other graphs and to define the meaning of a set of graphs by the way they reference each other. The semantics of networked graphs is defined by their mapping into logic programs. The expressiveness and computational complexity of networked graphs, varying by the set of constraints imposed on the underlying SPARQL queries, is investigated. We demonstrate the capabilities of networked graphs by a simple use case.

Model-driven Generation of APIs for OWL-based Ontologies (2010)

Scheglmann, Stefan ; Scherp, Ansgar ; Staab, Steffen

Existing tools for generating application programming interfaces (APIs) for ontologies lack sophisticated support for mapping the logics-based concepts of the ontology to an appropriate object-oriented implementation of the API. Such a mapping has to overcome the fundamental differences between the semantics described in the ontology and the pragmatics, i.e., structure, functionalities, and behavior implemented in the API. Typically, concepts from the ontology are mapped one-to-one to classes in the targeted programming language. Such a mapping only produces concept representations but not an API at the desired level of granularity expected by an application developer. We present a Model-Driven Engineering (MDE) process to generate customized APIs for ontologies. This API generation is based on the semantics defined in the ontology but also leverages additional information the ontology provides. This can be the inheritance structure of the ontology concepts, the scope of relevance of an ontology concept, or design patterns defined in the ontology.

Extended Description of the Survey on Common Strategies of Vocabulary Reuse in Linked Open Data Modeling (2014)

Schaible, Johann ; Gottron, Thomas ; Scherp, Ansgar

Modeling and publishing Linked Open Data (LOD) involves the choice of which vocabulary to use. This choice is far from trivial and poses a challenge to a Linked Data engineer. It covers the search for appropriate vocabulary terms, making decisions regarding the number of vocabularies to consider in the design process, as well as the way of selecting and combining vocabularies. Until today, there is no study that investigates the different strategies of reusing vocabularies for LOD modeling and publishing. In this paper, we present the results of a survey with 79 participants that examines the most preferred vocabulary reuse strategies of LOD modeling. Participants of our survey are LOD publishers and practitioners. Their task was to assess different vocabulary reuse strategies and explain their ranking decision. We found significant differences between the modeling strategies that range from reusing popular vocabularies, minimizing the number of vocabularies, and staying within one domain vocabulary. A very interesting insight is that the popularity in the meaning of how frequent a vocabulary is used in a data source is more important than how often individual classes and properties arernused in the LOD cloud. Overall, the results of this survey help in understanding the strategies how data engineers reuse vocabularies, and theyrnmay also be used to develop future vocabulary engineering tools.

Social networking platforms as creativity fostering systems: research model and exploratory study (2008)

Schaarschmidt, Mario ; Korflesch, Harald F. O. von

Social networking platforms are enabling users to create their own content, share this content with anyone they invite and organize connections with existing or new online contacts. Within these electronic environments users voluntarily add comments on virtual boards, distribute their search results or add information about their expertise areas to their social networking profiles and thereby share it with acquaintances, friends and increasingly even with colleagues in the corporate world. As a result, it is most likely that the underlying knowledge sharing processes result in many new and creative ideas. The objective of our research therefore is to understand if and how social social networking platforms can enforce creativity. In addition, we look at how these processes could be embedded within the organizational structures that influence innovative knowledge sharing behavior. The basis for our research is a framework which focuses on the relations between intrinsic motivation, creativity and social networking platforms. First results of our empirical investigation of a social software platform called "StudiVZ.net" proved that our two propositions are valid.

Crowdsourcing for Survey Research : where Amazon Mechanical Turks deviates from conventional survey methods (2015)

Schaarschmidt, Mario ; Ivens, Stefan ; Homscheid, Dirk ; Bilo, Pascal

Information systems research has started to use crowdsourcing platforms such as Amazon Mechanical Turks (MTurk) for scientific research, recently. In particular, MTurk provides a scalable, cheap work-force that can also be used as a pool of potential respondents for online survey research. In light of the increasing use of crowdsourcing platforms for survey research, the authors aim to contribute to the understanding of its appropriate usage. Therefore, they assess if samples drawn from MTurk deviate from those drawn via conventional online surveys (COS) in terms of answers in relation to relevant e-commerce variables and test the data in a nomological network for assessing differences in effects. The authors compare responses from 138 MTurk workers with those of 150 German shoppers recruited via COS. The findings indicate, inter alia, that MTurk workers tend to exhibit more positive word-of mouth, perceived risk, customer orientation and commitment to the focal company. The authors discuss the study- results, point to limitations, and provide avenues for further research.

Methods for Human-Machine Link Quality Management on the Web of Data (2022)

Sarasua, Cristina

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.

MapReduce with Deltas (2011)

Saile, David

The MapReduce programming model is extended slightly in order to use deltas. Because many MapReduce jobs are being re-executed over slightly changing input, processing only those changes promises significant improvements. Reduced execution time allows for more frequent execution of tasks, yielding more up-to-date results in practical applications. In the context of compound MapReduce jobs, benefits even add up over the individual jobs, as each job gains from processing less input data. The individual steps necessary in working with deltas are being analyzed and examined for efficiency. Several use cases have been implemented and tested on top of Hadoop. The correctness of the extended programming model relies on a simple correctness criterion.

Visual Teaching in Image Based Classification Problems (2008)

Röttger, Diana

PAPEL: Syntax and Semantics for Provenance-Aware Policy Definition (2010)

Ringelstein, Christoph ; Staab, Steffen

The processing of data is often restricted by contractual and legal requirements for protecting privacy and IPRs. Policies provide means to control how and by whom data is processed. Conditions of policies may depend on the previous processing of the data. However, existing policy languages do not provide means to express such conditions. In this work we present a formal model and language allowing for specifying conditions based on the history of data processing. We base the model and language on XACML.

Combined Non-Linear Pose Estimation from Points and Lines (2011)

Reinert, Bernhard ; Schumann, Martin ; Müller, Stefan

We present a non-linear camera pose estimator, which is able to handle a combined input of point and line feature correspondences. For three or more correspondences, the estimator works on any arbitrary number and choice of the feature type, which provides an estimation of the pose on a preferably small and flexible amount of 2D-3D correspondences. We also give an analysis of different minimization techniques, parametrizations of the pose data, and of error measurements between 2D and 3D data. These will be tested for the usage of point features, lines and the combination case. The result shows the most stable and fast working non-linear parameter set for pose estimation in model-based tracking.

Finite automata on unranked and unordered DAGs (2007)

Priese, Lutz

We introduce linear expressions for unrestricted dags (directed acyclic graphs) and finite deterministic and nondeterministic automata operating on them. Those dag automata are a conservative extension of the Tu,u-automata of Courcelle on unranked, unordered trees and forests. Several examples of dag languages acceptable and not acceptable by dag automata and some closure properties are given.

Design Patterns for API Analysis & Migration (2012)

Pehl, Joachim

Software projects typically rely on several, external libraries. The interface provided by such a library is called API (application programming interface). APIs often evolve over time, thereby implying the need to adapt applications that use them. There are also reasons which may call for the replacement of one library by another one, what also results in a need to adapt the applications where the library is replaced. The process of adapting applications to use a different API is called API migration. Doing API migration manually is a cumbersome task. Automated API migration is an active research field. A related field of research is API analysis which can also provide data for developing API migration tools. The following thesis investigates techniques and technologies for API analysis and API migration frameworks. To this end, design patterns are leveraged. These patterns are based on experience with API analysis and migration within the Software Languages Team.

Improvements of a First Aid Application Based on a Usability Study (2013)

Paschke, Janine Denise

This paper consists of the observation of existing first aid applications for smartphones and comparing them to a first aid application developed by the University of Koblenz called "Defi Now!". The main focus lies on examining "Defi Now!" in respect to its usability based on the dialogue principles referring to the seven software ergonomic principles due to the ISO 9241-110 standard. These are known as suitability for learning, controllability, error tolerance, self-descriptiveness, conformity with user expectations, suitability for the task, and suitability for individualization. Therefore a usability study was conducted with 74 participants. A questionnaire was developed, which was to be filled out by the test participants anonymously. The test results were used for an optimization of the app referring its' usability.

TwoUse: Integrating UML models and OWL ontologies (2007)

Parreiras, Fernando Silva ; Staab, Steffen ; Winter, Andreas

UML models and OWL ontologies constitute modeling approaches with different strength and weaknesses that make them appropriate for use of specifying different aspects of software systems. In particular, OWL ontologies are well suited to specify classes using an expressive logical language with highly flexible, dynamic and polymorphic class membership, while UML diagrams are much more suitable for specifying not only static models including classes and associations, but also dynamic behavior. Though MOF based metamodels and UML profiles for OWL have been proposed in the past, an integrated use of both modeling approaches in a coherent framework has been lacking so far. We present such a framework, TwoUse, for developing integrated models, comprising the benefits of UML models and OWL ontologies

A Full 2D/3D GraphSLAM System for Globally Consistent Mapping based on Manifolds (2012)

Neuhaus, Frank

Robotics research today is primarily about enabling autonomous, mobile robots to seamlessly interact with arbitrary, previously unknown environments. One of the most basic problems to be solved in this context is the question of where the robot is, and what the world around it, and in previously visited places looks like " the so-called simultaneous localization and mapping (SLAM) problem. We present a GraphSLAM system, which is a graph-based approach to this problem. This system consists of a frontend and a backend: The frontend- task is to incrementally construct a graph from the sensor data that models the spatial relationship between measurements. These measurements may be contradicting and therefore the graph is inconsistent in general. The backend is responsible for optimizing this graph, i. e. finding a configuration of the nodes that is least contradicting. The nodes represent poses, which do not form a regular vector space due to the contained rotations. We respect this fact by treating them as what they really are mathematically: manifolds. This leads to a very efficient and elegant optimization algorithm.

Generic task planning using semantic annotations in maps (2012)

Navarro Luzón, Carmen

The purpose of this master thesis is to enable the Robot Lisa to process complex commands and extract the necessary information in order to perform a complex task as a sequence of smaller tasks. This is intended to be achieved by the improvement of the understanding that Lisa has of her environment by adding semantics to the maps that she builds. The complex command itself will be expected to be already parsed. Therefore the way the input is processed to become a parsed command is out of the scope of this work. Maps that Lisa builds will be improved by the addition of semantic annotations that can include any kind of information that might be useful for the performance of generic tasks. This can include (but not necessarily limited to) hierarchical classifications of locations, objects and surfaces. The processing of the command in addition to some information of the environment shall trigger the performance of a sequence of actions. These actions are expected to be included in Lisa- currently implemented tasks and will rely on the currently existing modules that perform them. Nevertheless the aim of this work is not only to be able to use currently implemented tasks in a more complex sequence of actions but also make it easier to add new tasks to the complex commands that Lisa can perform.

Using Constraint Logic Programming for Modeling and Verifying Hierarchical Hybrid Automata (2009)

Mohammed, Ammar ; Stolzenburg, Frieder

Hybrid systems are the result of merging the two most commonly used models for dynamical systems, namely continuous dynamical systems defined by differential equations and discrete-event systems defined by automata. One can view hybrid systems as constrained systems, where the constraints describe the possible process flows, invariants within states, and transitions on the one hand, and to characterize certain parts of the state space (e.g. the set of initial states, or the set of unsafe states) on the other hand. Therefore, it is advantageous to use constraint logic programming (CLP) as an approach to model hybrid systems. In this paper, we provide CLP implementations, that model hybrid systems comprising several concurrent hybrid automata, whose size is only straight proportional to the size of the given system description. Furthermore, we allow different levels of abstraction by making use of hierarchies as in UML statecharts. In consequence, the CLP model can be used for analyzing and testing the absence or existence of (un)wanted behaviors in hybrid systems. Thus in summary, we get a procedure for the formal verification of hybrid systems by model checking, employing logic programming with constraints.

Multi-agent systems: modeling and verification using hybrid automata (2010)

Mohammed, Ammar ; Furbach, Ulrich

Hybrid automata are used as standard means for the specification and analysis of dynamical systems. Several researches have approached them to formally specify reactive Multi-agent systems situated in a physical environment, where the agents react continuously to their environment. The specified systems, in turn, are formally checked with the help of existing hybrid automata verification tools. However, when dealing with multi-agent systems, two problems may be raised. The first problem is a state space problem raised due to the composition process, where the agents have to be parallel composed into an agent capturing all possible behaviors of the multi-agent system prior to the verification phase. The second problem concerns the expressiveness of verification tools when modeling and verifying certain behaviors. Therefore, this paper tackles these problems by showing how multi-agent systems, specified as hybrid automata, can be modeled and verified using constraint logic programming(CLP). In particular, a CLP framework is presented to show how the composition of multi-agent behaviors can be captured dynamically during the verification phase. This can relieve the state space complexity that may occur as a result of the composition process. Additionally, the expressiveness of the CLP model flexibly allows not only to model multi-agent systems, but also to check various properties by means of the reachability analysis. Experiments are promising to show the feasibility of our approach.

RoboCup 2017 – homer@UniKoblenz (Germany) (2018)

Memmesheimer, Raphael

This paper describes the robot Lisa used by team homer@UniKoblenz of the University of Koblenz Landau, Germany, for the participation at the RoboCup@Home 2017 in Nagoya, Japan. A special focus is put on novel system components and the open source contributions of our team. We have released packages for object recognition, a robot face including speech synthesis, mapping and navigation, speech recognition interface via android and a GUI. The packages are available (and new packages will be released) on http://wiki.ros.org/agas-ros-pkg.

RoboCup 2016 – homer@UniKoblenz (Germany) (2018)

Memmesheimer, Raphael

This paper describes the robot Lisa used by team homer@UniKoblenz of the University of Koblenz Landau, Germany, for the participation at the RoboCup@Home 2016 in Leipzig, Germany. A special focus is put on novel system components and the open source contributions of our team. We have released packages for object recognition, a robot face including speech synthesis, mapping and navigation, speech recognition interface via android and a GUI. The packages are available (and new packages will be released) on http://wiki.ros.org/agas-ros-pkg.

CAMPUS NEWS - artificial intelligence methods combined for an intelligent information network (2008)

Maron, Markus ; Read, Kevin ; Schulze, Michael

In this paper we describe a network for distributing personalised information with the usage of artificial intelligence methods. Reception of this information should be possible with everyday mobile equipment. Intelligent filtering and spam protection aim at integrating this technology into our environment. Information on the system architecture and usage of the installation are also presented.

An empirical study to evaluate the location of advertisement panels by using a mobile marketing tool (2009)

Magnus, Sebastian ; Maron, Markus

The efficiency of marketing campaigns is a precondition for business success. This paper discusses a technique to transfer advertisement content vie Bluetooth technology and collects market research information at the same time. Conventional advertisement media were enhanced by devices to automatically measure the number, distance, frequency and exposure time of passersby, making information available to evaluate both the wireless media as well as the location in general. This paper presents a study analyzing these data. A cryptographic one-way function protects privacy during data acquisition.

A public key infrastructure in ambient information and transaction systems (2010)

Magnus, Sebastian ; Maron, Markus

Conventional security infrastructures in the Internet cannot be directly adopted to ambient systems, especially if based on short-range communication channels: Personal, mobile devices are used and the participants are present during communication, so privacy protection is a crucial issue. As ambient systems cannot rely on an uninterrupted connection to a Trust Center, certiffed data has to be veriffed locally. Security techniques have to be adjusted to the special environment. This paper introduces a public key infrastructure (PKI) to provide secure communication channels with respect to privacy, confidentiality, data integrity, non-repudiability, and user or device authentication. It supports three certiffcate levels with a different balance between authenticity and anonymity. This PKI is currently under implementation as part of the iCity project.

Security in Distance Vector Algorithms (2011)

Lück, Stefanie

Distance vector routing protocols are interior gateway protocols in which every router sets up a routing table with the help of the information it receives from its neighboring routers. The routing table contains the next hops and associated distances on the shortest paths to every other router in the network. Security mechanisms implemented in distance vector routing protocols are insufficient. It is rather assumed that the environment is trustworthy. However, routers can be malicious for several reasons and manipulate routing by injecting false routing updates. Authenticity and integrity of transmitted routing updates have to be guaranteed and at the same time performance and benefits should be well-balanced. In this paper several approaches that aim at meeting the above mentioned conditions are examined and their advantages and disadvantages are compared.

Probability Propagation Nets and Duality (2012)

Lautenbach, Kurt ; Susewind, Kerstin

The paper deals with a specific introduction into probability propagation nets. Starting from dependency nets (which in a way can be considered the maximum information which follows from the directed graph structure of Bayesian networks), the probability propagation nets are constructed by joining a dependency net and (a slightly adapted version of) its dual net. Probability propagation nets are the Petri net version of Bayesian networks. In contrast to Bayesian networks, Petri nets are transparent and easy to operate. The high degree of transparency is due to the fact that every state in a process is visible as a marking of the Petri net. The convenient operability consists in the fact that there is no algorithm apart from the firing rule of Petri net transitions. Besides the structural importance of the Petri net duality there is a semantic matter; common sense in the form of probabilities and evidencebased likelihoods are dual to each other.

Applying Probability Propagation Nets (2012)

Lautenbach, Kurt ; Susewind, Kerstin

In this paper, we demonstrate by means of two examples how to work with probability propagation nets (PPNs). The fiirst, which comes from the book by Peng and Reggia [1], is a small example of medical diagnosis. The second one comes from [2]. It is an example of operational risk and is to show how the evidence flow in PPNs gives hints to reduce high losses. In terms of Bayesian networks, both examples contain cycles which are resolved by the conditioning technique [3].

Probability propagation nets (2007)

Lautenbach, Kurt ; Pinl, Alexander

A class of high level Petri nets, called "probability propagation nets", is introduced which is particularly useful for modeling probability and evidence propagation. These nets themselves are well suited to represent the probabilistic Horn abduction, whereas specific foldings of them will be used for representing the flows of probabilities and likelihoods in Bayesian networks.

The Quaternality of Simulation: An Event/Non-Event Approach (2012)

Lautenbach, Kurt

Dualizing marked Petri nets results in tokens for transitions (t-tokens). A marked transition can strictly not be enabled, even if there are sufficient "enabling" tokens (p-tokens) on its input places. On the other hand, t-tokens can be moved by the firing of places. This permits flows of t-tokens which describe sequences of non-events. Their benefiit to simulation is the possibility to model (and observe) causes and effects of non-events, e.g. if something is broken down.

A Petri net approach for propagating probabilities and mass functions (2010)

Lautenbach, Kurt

This paper has a twofold concern. First, to show that probability propagation nets (PPNs) can be derived from formulae for conditional probabilities. Second, to show that PPNs are usable for (local) propagations of mass distributions, too, if the inscriptions are suitably adapted.

Requirements for Health Care Related Websites in Russia: results from an Analysis of American British and German Examples (2011)

Lantsberg, Anna ; Troitzsch, Klaus G.

The paper is devoted to solving a problem of the development of the website of Russian municipal policlinics and provides a selection of a set of elements which should be posted on a website. Such elements are necessary to provide citizens with correct and ergonomic e-services. The insufficient development of an infrastructure of institutions of public and municipal administration (particularly, healthcare institutions) in Russia made it necessary to analyze webresources used in different countries at different levels of providing medical services. The information resources of medical treatment facilities of the United Kingdom, of the United Statesrnof America and of the Federal Republic of Germany were researched separately for three existing economic models of healthcare. A set of criteria for the assessment of medical webresources was developed.

Distributed Natural Language Search Using Graph-Based Parsing (2013)

Kurz, Nadine Sina

We present the conceptual and technological foundations of a distributed natural language interface employing a graph-based parsing approach. The parsing model developed in this thesis generates a semantic representation of a natural language query in a 3-staged, transition-based process using probabilistic patterns. The semantic representation of a natural language query is modeled in terms of a graph, which represents entities as nodes connected by edges representing relations between entities. The presented system architecture provides the concept of a natural language interface that is both independent in terms of the included vocabularies for parsing the syntax and semantics of the input query, as well as the knowledge sources that are consulted for retrieving search results. This functionality is achieved by modularizing the system's components, addressing external data sources by flexible modules which can be modified at runtime. We evaluate the system's performance by testing the accuracy of the syntactic parser, the precision of the retrieved search results as well as the speed of the prototype.

Simulating medical objects simulation using an artificial neural network whose structure is based on adaptive resonance theory (2011)

Kryuchin, Oleg V. ; Arzamastsev, Alexander A. ; Zenkova, Natalia ; Troitzsch, Klaus G. ; Sletkov, Denis V.

This paper describes artificial neural networks which are based on the adaptive resonance theory. The usage of these artificial neural networks for classification tasks is presented. The example uses is the classification of patient health from the results of general blood analysis.

Simulating social objects with an artificial neural network using a computer cluster (2011)

Kryuchin, Oleg V. ; Arzamastsev, Alexander A. ; Troitzsch, Klaus G. ; Zenkova, Natalia

This paper describes results of the simulation of social objects, the dependence of schoolchildren's professional abilities on their personal characteristics. The simulation tool is the artificial neural network (ANN) technology. Results of a comparison of the time expense for training the ANN and for calculating the weight coefficients with serial and parallel algorithms, respectively, are presented.

The prediction of currency exchange rates using artificial neural networks (2011)

Kryuchin, Oleg V. ; Arzamastsev, Alexander A. ; Troitzsch, Klaus G.

This paper describes the analysis of a neural network used to predict currency exchange rates in comparison to technical analysis. The neural network structures used are a multilayer perceptron and a Volterra network.

A universal simulator based on artificial neural networks for computer clusters (2011)

Kryuchin, Oleg V. ; Arzamastsev, Alexander A. ; Troitzsch, Klaus G.

This paper describes parallel algorithms for training artifcial neural networks. Possible levels of parallelity are presented. Experiments for checking the effciency of algorithms are discussed.

Comparing the efficiency of serial and parallel algorithms for training artificial neural networks using computer clusters (2011)

Kryuchin, Oleg V. ; Arzamastsev, Alexander A. ; Troitzsch, Klaus G.

An estimation of the number of multiplication and addition operations for training artififfcial neural networks by means of consecutive and parallel algorithms on a computer cluster is carried out. The evaluation of the efficiency of these algorithms is developed. The multilayer perceptron, the Volterra network and the cascade-correlation network are used as structures of artififfcial neural networks. Different methods of non-linear programming such as gradient and non-gradient methods are used for the calculation of the weight coefficients.

Concept Network Extraction from Text (2013)

Krukow, Oliver

Large amounts of qualitative data make the utilization of computer-assisted methods for their analysis inevitable. In this thesis Text Mining as an interdisciplinary approach, as well as the methods established in the empirical social sciences for analyzing written utterances are introduced. On this basis a process of extracting concept networks from texts is outlined and the possibilities of utilitzing natural language processing methods within are highlighted. The core of this process is text processing, to whose execution software solutions supporting manual as well as automated work are necessary. The requirements to be met by these solutions, against the background of the initiating project GLODERS, which is devoted to investigating extortion racket systems as part of the global fiσnancial system, are presented, and their fulσlment by the two most preeminent candidates reviewed. The gap between theory and pratical application is closed by a prototypical application of the method to a data set of the research project utilizing the two given software solutions.

Which work-life balance offers should companies prowide nowadays? (2016)

Krath, Jeanine ; Zerwas, Claire ; Korflesch, Harald F. O. von

In order to enhance the company’s appeal for potential employees and improve the satisfaction of already salaried workers, it is necessary to offer a variety of work-life balance measures. But as their implementation causes time and financial costs, a prioritization of measures is needed. To express a recommendation for companies, this study is led by the questions if there are work-life balance measures which have more impact on employee satisfaction than others, how big the relative impact of work-life balance measures on job satisfaction in comparison to other work and private life variables is, if there is a relation between the effectiveness of measures and their use and if there is a difference between the measures which are most important from the employees’ perspective and the companies’ offers. These questions are formulated in eight research hypotheses which are examined in a quantitative research design with online survey data from 289 employees of fifteen different German companies. The formation of a hierarchy of the effectiveness of measures towards job satisfaction as well as the investigation of the relative impact in comparison to other variables is performed using a multiple regression analysis, whilst the differences between employees’ expectations and the availability of offers are examined with t-tests. Support in childcare, support in voluntary activities and teambuilding events have a significantly higher impact on job satisfaction than other work-life balance measures, and their potential use is higher than the actual use which leads to the conclusion that there is yet potential for companies to improve their employees’ satisfaction by implementing these measures. In addition, flexible work hours, flexible work locations and free time and overtime accounts are the most important measures from the employees’ point of view and already widely offered by the surveyed companies. In general, the overall use of the available measures and the quantity of offered measures are more important with regard to job satisfaction than the specific kind of measure. In addition, work-life balance measures are more important towards job satisfaction for younger people.

Introducing Entrepeneurial Design Thinking (2012)

Korflesch, Harald F. O. von ; Mokanis, Ilias ; Zerwas, Dorothée

The objective of this contribution is to conceptually analyze the potentials of entrepreneurial design thinking as being a rather new method for entrepreneurship education. Based on a literature review of different design thinking concepts we carve out a generic design thinking model upon we conceptually build a new model that considers entrepreneurial thinking as a valuable characteristic. The results of our work show that the characteristics of entrepreneurial design thinking can enhance entrepreneurship education by supporting respective action fields of entrepreneurial learning. In addition we reveal that entrepreneurial design thinking offers beneficial guidelines for the design of entrepreneurship education programs.

What impedes Consumers’ Delivery Drone Service Adoption? (2020)

Knobloch, Marius ; Schaarschmidt, Mario

Despite widespread plans of big companies like Amazon and Google to develop unmanned delivery drones, scholarly research in this field is scarce, especially in the information systems field. From technical and legal perspectives, drone delivery in last-mile scenarios is in a quite mature state. However, estimates of user acceptance are varying between high skepticism and exaggerated optimism. This research follows a mixed method approach consisting both qualitative and quantitative research, to identify and test determinants of consumer delivery drone service adoption. The qualitative part rests on ten interviews among average consumers, who use delivery services on a regular basis. Insights gained from the qualitative part were used to develop an online survey and to assess the influence of associated risks on adoption intentions. The quantitative results show that especially financial and physical risks impede drone delivery service adoption. Delivery companies who are currently thinking about providing a delivery drone service may find these results useful when evaluating usage behaviors in the future market for delivery drones.

Reproducible Wrapper for API Migration (2011)

Knauf, Malte

API migration refers to the change of a used API to a different API in a program. A special case is called wrapper-based API migration. The API change is done without touching the program but the old API is reimplemented by means of the from now on used one. This so called wrapper has the interface of the reimplemented API but uses the implementation of the new one. This is an interesting approach because the wrapper can be used in each program, which uses the old API. To make this approach reproducible we study a ranking-based method for implementing a wrapper, where we always implement the method with the highest priority depending on failing test cases. Thus, we can reconstruct each implementation step. We first develop an infrastructure to run and log test suites of Java projects that use an API, which we want to change. We then build a wrapper for a given API using the ranking-based approach.

Mobile Facets - faceted search and exploration of open social media data on a touchscreen mobile phone (2011)

Kleinen, Alexander ; Scherp, Ansgar ; Staab, Steffen

We present the user-centered, iterative design of Mobile Facets, a mobile application for the faceted search and exploration of a large, multi-dimensional data set of social media on a touchscreen mobile phone. Mobile Facets provides retrieval of resources such as places, persons, organizations, and events from an integration of different open social media sources and professional content sources, namely Wikipedia, Eventful, Upcoming, geo-located Flickr photos, and GeoNames. The data is queried live from the data sources. Thus, in contrast to other approaches we do not know in advance the number and type of facets and data items the Mobile Facets application receives in a specific contextual situation. While developingrnMobile Facets, we have continuously evaluated it with a small group of fifive users. We have conducted a task-based, formative evaluation of the fifinal prototype with 12 subjects to show the applicability and usability of our approach for faceted search and exploration on a touchscreen mobile phone.

Iterative Signing of RDF(S) Graphs, Named Graphs, and OWL Graphs: Formalization and Application (2013)

Kasten, Andreas ; Scherp, Ansgar

When publishing graph data on the web such as vocabulariesrnusing RDF(S) or OWL, one has only limited means to verify the authenticity and integrity of the graph data. Today's approaches require a high signature overhead and do not allow for an iterative signing of graph data. This paper presents a formally defined framework for signing arbitrary graph data provided in RDF(S), Named Graphs, or OWL. Our framework supports signing graph data at different levels of granularity: minimum self-contained graphs (MSG), sets of MSGs, and entire graphs. It supports for an iterative signing of graph data, e. g., when different parties provide different parts of a common graph, and allows for signing multiple graphs. Both can be done with a constant, low overhead for the signature graph, even when iteratively signing graph data.

Image annotation tool for collecting expert knowledge (2008)

Jeong, Yoo-Jin

VocVille - a casual social game for learning vocabulary (2011)

Jensen, Michel

This paper introduces Vocville, a causal online game for learning vocabularies. I am creating this application for my master thesis of my career as a "Computervisualist" (computer visions) for the University of Koblenz - Landau. The application is an online browser game based on the idea of the really successful Facebook game FarmVille. The application is seperated in two parts; a Grails application manages a database which holds the game objects like vocabulary, a Flex/Flash application generates the actual game by using these data. The user can create his own home with everything in it. For creating things, the user has to give the correct translation of the object he wants to create several times. After every query he has to wait a certain amount of time to be queried again. When the correct answer is given sufficient times, the object is builded. After building one object the user is allowed to build others. After building enough objects in one area (i.e. a room, a street etc.) the user can activate other areas by translating all the vocabularies of the previous area. Users can also interact with other users by adding them as neighbors and then visiting their homes or sending them gifts, for which they have to fill in the correct word in a given sentence.

Cloud Computing in German Higher Educational Institutions (2012)

Jenhani, Amor

Only little information is available about the diffusion of cloud computing in German higher educational institutions. A better understanding of the state of the art in this field would support the modernization of the higher educational institutions in Germany and allow the development of more adequate cloud products and more appropriate business models for this niche. For this purpose, a literature research on Cloud Computing and IT-diffusion will be run and an empirical investigation with an online questionnaire addressed to higher educational institutions in Germany will be performed to illustrate the state of the art of Cloud Computing in German higher educational institutions as well as the threats and opportunities perceived by employees of higher educational institutions data centers connected to the usage of the cloud. In addition to that, different experts from universities and businesses will be interviewed to complete the knowledge and information collected through the online questionnaire and during the research phase. The expected results will serve to create a recommendation for higher educational institutions in Germany about either they should migration to the cloud or not and introduce a list of guiding questions of critical issues to consider before using cloud-computing technologies.

Extension of a didactic media competence model by privacy risk (2016)

Hug, Alexander ; Grimm, Rüdiger

Six and Gimmler have identified concrete capabilities that enable users to use the Internet in a competent way. Their media competence model can be used for the didactical design of media usage in secondary schools. However, the special challenge of security awareness is not addressed by the model. In this paper, the important dimension of risk and risk assessment will be introduced into the model. This is especially relevant for the risk of the protection of personal data and privacy. This paper will apply the method of IT risk analysis in order to select those dimensions of the Six/Gimmler media competence model that are appropriate to describe privacy aware Internet usage. Privacy risk aware decisions for or against the Internet usage is made visible by the trust model of Mayer et al.. The privacy extension of the competence model will lead to a measurement of the existing privacy awareness in secondary schools, which, in turn, can serve as a didactically well-reasoned design of Informatics modules in secondary schools. This paper will provide the privacy-extended competence model, while empirical measurement and module design is planned for further research activities.

Extraction of Natural Feature Descriptors on Mobile GPUs (2012)

Hofmann, Robert

In this thesis the feasibility of a GPGPU (general-purpose computing on graphics processing units) approach to natural feature description on mobile phone GPUs is assessed. To this end, the SURF descriptor [4] has been implemented with OpenGL ES 2.0/GLSL ES 1.0 and evaluated across different mobile devices. The implementation is multiple times faster than a comparable CPU variant on the same device. The results proof the feasibility of modern mobile graphics accelerators for GPGPU tasks especially for the detection phase in natural feature tracking used in augmented reality applications. Extensive analysis and benchmarking of this approach in comparison to state of the art methods have been undertaken. Insights into the modifications necessary to adapt and modify the SURF algorithm to the limitations of a mobile GPU are presented. Further, an outlook for a GPGPU-based tracking pipeline on a mobile device is provided.

Implementation of the Model "Simulating Collective Misbelief" into a NetLogo environment (2012)

Hemmerich, Kai Manuel

The goal of this Bachelor thesis is to implement and evaluate the "Simulating of Collective Misbelief"-model into the NetLogo programming language. Therefore, the model requirements have to be specified and implemented into the NetLogo environment. Further tool-related re-quirements have to be specified to enable the model to work in NetLogo. After implementation several simulations will be conducted to answer the research question stated above.

Combining Pose Tracking with Sketch Recognition for Augmented Drawings (2012)

Heitger, Jan

Augmented Reality bedeutet eine reale Umgebung mit, meistens grafischen, virtuellen Inhalten zu erweitern. Oft sind dabei die virtuellen Inhalte der Szene jedoch nur ein Overlay und interagieren nicht mit den realen Bestandteilen der Szene. Daraus ergibt sich ein Authentizitätsproblem für Augmented Reatliy Anwendungen. Diese Arbeit betrachtet Augmented Reality in einer speziellen Umgebung, mit deren Hilfe eine authentischere Darstellung möglich ist. Ziel dieserArbeitwar die Erstellung eines Systems, das Zeichnungen durch Techniken der Augmented Reality mit virtuellen Inhalten erweitert. Durch das Anlegen einer Repräsentation soll es der Anwendung dabei möglich sein die virtuellen Szeneelementemit der Zeichnung interagieren zu lassen. Dazu wurden verschiedene Methoden aus den Bereichen des Pose Tracking und der Sketch Recognition disktutiert und für die Implementierung in einem prototypischen System ausgewählt. Als Zielhardware fungiert ein Android Smartphone. Kontext der Zeichnungen ist eine Dungeon Karte, wie sie in Rollenspielen vorkommt. Die virtuellen Inhalte nehmen dabei die Form von Bewohnern des Dungeons an, welche von einer Agentensimulation verwaltet werden. Die Agentensimulation ist Gegenstand einer eigenen Diplomarbeit [18]. Für das Pose Tracking wurde ARToolkitPlus eingesetzt, ein optisches Tracking System, das auf Basis von Markern arbeitet. Die Sketch Recognition ist dafür zuständig die Inhalte der Zeichnung zu erkennen und zu interpretieren. Dafür wurde ein eigener Ansatz implementiert der Techniken aus verschiedenen Sketch Recognition Systemen kombiniert. Die Evaluation konzentriert sich auf die technischen Aspekte des Systems, die für eine authentische Erweiterung der Zeichnung mit virtuellen Inhalten wichtig sind.

Categorising Social Media Business Risks (2014)

Hausmann, Verena ; Williams, Susan P.

The aim of this paper is to identify and understand the risks and issues companies are experiencing from the business use of social media and to develop a framework for describing and categorising those social media risks. The goal is to contribute to the evolving theorisation of social media risk and to provide a foundation for the further development of social media risk management strategies and processes. The study findings identify thirty risk types organised into five categories (technical, human, content, compliance and reputational). A risk-chain is used to illustrate the complex interrelated, multi-stakeholder nature of these risks and directions for future work are identified.

Developing a Framework for Web Analytics (2012)

Hausmann, Verena

The World Wide Web (WWW) has become a very important communication channel. Its usage has steadily grown within the past. Interest by website owners in identifying user behaviour has been around since Tim Berners-Lee developed the first web browser in 1990. But as the influence of the online channel today eclipses all other media the interest in monitoring website usage and user activities has intensified as well. Gathering and analysing data about the usage of websites can help to understand customer behaviour, improve services and potentially increase profit. It is further essential for ensuring effective website design and management, efficient mass customization and effective marketing. Web Analytics (WA) is the area addressing these considerations. However, changing technologies and evolving Web Analytic methods and processes present a challenge to organisations starting with Web Analytic programmes. Because of lacking resources in different areas and other types of websites especially small and medium-sized enterprises (SME) as well as non-profit organisations struggle to operate WA in an effective manner. This research project aims to identify the existing gap between theory, tool possibilities and business needs for undertaking Web Analytic programmes. Therefore the topic was looked at from three different ways: the academic literature, Web Analytic tools and an interpretative case study. The researcher utilized an action research approach to investigate Web Analytics presenting an holistic overview and to identify the gaps that exists. The outcome of this research project is an overall framework, which provides guidance for SMEs who operate information websites on how to proceed in a Web Analytic programme.

Categorization and recognition of ontology refactoring pattern (2010)

Gröner, Gerd ; Staab, Steffen

Ontologies play an important role in knowledge representation for sharing information and collaboratively developing knowledge bases. They are changed, adapted and reused in different applications and domains resulting in multiple versions of an ontology. The comparison of different versions and the analysis of changes at a higher level of abstraction may be insightful to understand the changes that were applied to an ontology. While there is existing work on detecting (syntactical) differences and changes in ontologies, there is still a need in analyzing ontology changes at a higher level of abstraction like ontology evolution or refactoring pattern. In our approach we start from a classification of model refactoring patterns found in software engineering for identifying such refactoring patterns in OWL ontologies using DL reasoning to recognize these patterns.

SOA-Security (2007)

Grimm, Rüdiger ; Mehr, Farid ; Meletiadou, Anastasia ; Pähler, Daniel ; Uerz, Ilka

This paper is a part of the ASG project (Adaptive Services Grid) and addresses some IT security issues of service oriented architectures. It defines a service-oriented security concept, it explores the SOA security challenge, it describes the existing WS-Security standard, and it undertakes a first step into a survey on best practice examples. In particular, the ASG middleware platform technology (JBossWS) is analyzed with respect to its ability to handle security functions.

Security requirements for non-political Internet voting (2007)

Grimm, Rüdiger ; Krimmer, Robert ; Meißner, Nils ; Reinhard, Kai ; Volkamer, Melanie ; Weinand, Marcel ; Helbach, Jörg

This paper describes the development of security requirements for non-political Internet voting. The practical background is our experience with the Internet voting within the Gesellschaft für Informatik (GI - Informatics Society) 2004 and 2005. The theoretical background is the international state-of-the-art of requirements about electronic voting, especially in the US and in Europe. A focus of this paper is on the user community driven standardization of security requirements by means of a Protection Profile of the international Common Criteria standard.

Virtual Goods + ODRL 2012 (2012)

Grimm, Rüdiger ; Colin, Jean-Noel

This is the 10th international workshop for technical, economic, and legal aspects of business models for virtual goods incorporating the 8th ODRL community group meeting. This year we did not call for completed research results, but we invited PhD students to present and discuss their ongoing research work. In the traditional international group of virtual goods and ODRL researchers we discussed PhD research from Belgium, Brazil, and Germany. The topics focused on research questions about rights management in the Internet and e-business stimulation. In the center of rights management stands the conception of a formal policy expression that can be used for human readable policy transparency, as well as for machine readable support of policy conformant systems behavior up to automatic policy enforcement. ODRL has proven to be an ideal basis for policy expressions, not only for digital copy rights, but also for the more general "Policy Awareness in the World of Virtual Goods". In this sense, policies support the communication of virtual goods, and they are a virtualization of rules-governed behavior themselves.

LOVER: Support for Modeling Data Using Linked Open Vocabularies (2013)

Gottron, Thomas ; Schaible, Johann ; Scheglmann, Stefan ; Scherp, Ansgar

Various best practices and principles guide an ontology engineer when modeling Linked Data. The choice of appropriate vocabularies is one essential aspect in the guidelines, as it leads to better interpretation, querying, and consumption of the data by Linked Data applications and users. In this paper, we present the various types of support features for an ontology engineer to model a Linked Data dataset, discuss existing tools and services with respect to these support features, and propose LOVER: a novel approach to support the ontology engineer in modeling a Linked Data dataset. We demonstrate that none of the existing tools and services incorporate all types of supporting features and illustrate the concept of LOVER, which supports the engineer by recommending appropriate classes and properties from existing and actively used vocabularies. Hereby, the recommendations are made on the basis of an iterative multimodal search. LOVER uses different, orthogonal information sources for finding terms, e.g. based on a best string match or schema information on other datasets published in the Linked Open Data cloud. We describe LOVER's recommendation mechanism in general and illustrate it alongrna real-life example from the social sciences domain.

Path tracing via comparison of received signal strength within WiFi landscapes (2011)

Gauterin, Alvaro

This bachelor thesis deals with the comparison related to the similarity of recorded WiFi patterns during the tracing of a path through the streets of a large city. Both MAC address only comparison has been investigated as well as the incorporation of RSSI values, whereby the localization accuracy has been evaluated. Methods for the detection of different types and combinations of loops in the path are demonstrated likewise the attempt to estimate the degree of urban development in the environment of the user by assessing the received signal strength and signal-to-noise ratio of GPS satellites and GSM cell towers. In order to observe a user- proximity to a certain spot on a large public square the absorption of WiFi signals by the human body has been taken into account. Finally, the results of a comparison of the computing performance of a modern smartphone versus the alternative of remote calculation on a server including data transmission via cellular data network are presented.

Real-Time Implementation of OpenVDB Rendering (2022)

Gaida, Sebastian

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.

Semantically Guided Evolution of SHI ABoxes (2013)

Furbach, Ulrich ; Schon, Claudia

This paper presents a method for the evolution of SHI ABoxes which is based on a compilation technique of the knowledge base. For this the ABox is regarded as an interpretation of the TBox which is close to a model. It is shown, that the ABox can be used for a semantically guided transformation resulting in an equisatisfiable knowledge base. We use the result of this transformation to effciently delete assertions from the ABox. Furthermore, insertion of assertions as well as repair of inconsistent ABoxes is addressed. For the computation of the necessary actions for deletion, insertion and repair, the E-KRHyper theorem prover is used.

Applications of Automated Reasoning (2007)

Furbach, Ulrich ; Obermaier, Claudia

This paper offers an informal overview and discussion on first order predicate logic reasoning systems together with a description of applications which are carried out in the Artificial Intelligence Research Group of the University in Koblenz. Furthermore the technique of knowledge compilation is shortly introduced.

Knowledge compilation for description logics (2007)

Furbach, Ulrich ; Obermaier, Claudia

Knowledge compilation is a common technique for propositional logic knowledge bases. The idea is to transform a given knowledge base into a special normal form ([MR03],[DH05]), for which queries can be answered efficiently. This precompilation step is very expensive but it only has to be performed once. We propose to apply this technique to knowledge bases defined in Description Logics. For this, we introduce a normal form, called linkless concept descriptions, for ALC concepts. Further we present an algorithm, based on path dissolution, which can be used to transform a given concept description into an equivalent linkless concept description. Finally we discuss a linear satisfiability test as well as a subsumption test for linkless concept descriptions.

Hybrid multiagent systems with timed synchronization (2007)

Furbach, Ulrich ; Murray, Jan ; Schmidsberger, Falk ; Stolzenburg, Frieder

This paper shows how multiagent systems can be modeled by a combination of UML statecharts and hybrid automata. This allows formal system specification on different levels of abstraction on the one hand, and expressing real-time system behavior with continuous variables on the other hand. It is not only shown how multi-robot systems can be modeled by a combination of hybrid automata and hierarchical state machines, but also how model checking techniques for hybrid automata can be applied. An enhanced synchronization concept is introduced that allows synchronization taking time and avoids state explosion to a certain extent.

CAMPUS NEWS - an information network for pervasive universities (2007)

Furbach, Ulrich ; Maron, Markus ; Read, Kevin

In this paper we describe a network for distributing personalized information within a pervasive university. We discuss the system architecture of our Bluetooth-based CampusNews-system, both, from the administrator and the user viewpoint. We furthermore present first statistical data about the usage of the partial installation at the Koblenz campus together with an outlook to future work.

CAMPUS NEWS - an intelligent Bluetooth-based mobile information network (2007)

Furbach, Ulrich ; Maron, Markus ; Read, Kevin

In this paper we describe a network for distributing personalized Information in a metropolitan area. We discuss the system architecture of our Bluetooth-based information system as well as the reasoning process that fits users" needs with potential messages. We furthermore present our findings on parallelizing Bluetooth connection setup and performance.

Location based information systems (2007)

Furbach, Ulrich ; Maron, Markus ; Read, Kevin

In this paper we describe a series of projects on location based and personalised information systems. We start wit a basic research project and we show how we came with the help of two other more application oriented project to a product. This is developed by a consortium of enterprises and it already is in use in the city of Koblenz.

Identifying Legacy Code for Service Implementation using Dynamic Analysis and Data Mining (2011)

Fuhr, Andreas

Identifying reusable legacy code able to implement SOA services is still an open research issue. This master thesis presents an approach to identify legacy code for service implementation based on dynamic analysis and the application of data mining techniques. rnrnAs part of the SOAMIG project, code execution traces were mapped to business processes. Due to the high amount of traces generated by dynamic analyses, the traces must be post-processed in order to provide useful information. rnrnFor this master thesis, two data mining techniques - cluster analysis and link analysis - were applied to the traces. First tests on a Java/Swing legacy system provided good results, compared to an expert- allocation of legacy code.

The motives for B2B integration : an empirical study (2011)

Frick, Norbert ; Schubert, Petra

With the ongoing process of building business networks in today- economy, business to-business integration (B2B Integration) has become a strategic tool for utilizing and optimizing information exchange between business partners. Industry and academia have made remarkable progress in implementing and conceptualizing different kinds of electronic inter-company relationships in the last years. Nevertheless, academic findings generally focus exclusively on certain aspects of the research object, e.g. document standards, process integration or other descriptive criteria. Without arncommon framework these results stay unrelated and their mutual impact on each other remains largely unexplained. In this paper we explore motivational factors of B2B integration in practice. In a research project using a uniform taxonomy (eXperience methodology) we classified real-world B2B integration projects from a pool of over 400 case studies using a pre-developed framework for integration scenarios. The result of our partly exploratory research shows the influence of the role of a company in the supply chain and its motive to invest in a B2B solution.

Does a semantic desktop facilitate your daily tasks? (2008)

Franz, Thomas ; Scherp, Ansgar ; Staab, Steffen

Semantic desktop environments aim at improving the effectiveness and efficiency of users carrying out daily tasks within their personal information management infrastructure (PIM). They support the user by transferring and exploiting the explicit semantics of data items across different PIM applications. Whether such an approach does indeed reach its aim of facilitating users" life andâ€”if soâ€”to which extent, however, remains an open question that we address in this paper with the first summative evaluation of a semantic desktop approach. We approach the research question exploiting our own semantic desktop infrastructure, X-COSIM. As data corpus, we have used over 100 emails and 50 documents extracted from the organizers of a conference-like event at our university. The evaluation has been carried out with 18 subjects. We have developed a test environment to evaluate COSIMail and COSIFile, two semantic PIM applications based on X-COSIM. As result, we have found a significant improvement for typical PIM tasks compared to a standard desktop environment.

The DLE-Hyper Tableau Calculus: a Decision Procedure for SHIQ (2012)

Faßbender, Dennis

This thesis introduces the DLE-Hyper Tableau calculus, an extension of the E-Hyper Tableau calculus that is a decision procedure for the Description Logic SHIQ.

The STOR component system interim report (2009)

Falkowski, Kerstin ; Ebert, Jürgen

The STOR project aims at the development of a scientific component system employing models and knowledge for object recognition in images. This interim report elaborates on the requirements for such a component system, structures the application area by identifying a large set of basic operations, and shows how a set of appropriate data structures and components can be derived. A small case studies exemplifies the approach.

Edge Formation and its Influence in Machine Learning (2022)

Espín-Noboa, Lisette

Social networks are ubiquitous structures that we generate and enrich every-day while connecting with people through social media platforms, emails, and any other type of interaction. While these structures are intangible to us, they carry important information. For instance, the political leaning of our friends can be a proxy to identify our own political preferences. Similarly, the credit score of our friends can be decisive in the approval or rejection of our own loans. This explanatory power is being leveraged in public policy, business decision-making and scientific research because it helps machine learning techniques to make accurate predictions. However, these generalizations often benefit the majority of people who shape the general structure of the network, and put in disadvantage under-represented groups by limiting their resources and opportunities. Therefore it is crucial to first understand how social networks form to then verify to what extent their mechanisms of edge formation contribute to reinforce social inequalities in machine learning algorithms. To this end, in the first part of this thesis, I propose HopRank and Janus two methods to characterize the mechanisms of edge formation in real-world undirected social networks. HopRank is a model of information foraging on networks. Its key component is a biased random walker based on transition probabilities between k-hop neighborhoods. Janus is a Bayesian framework that allows to identify and rank plausible hypotheses of edge formation in cases where nodes possess additional information. In the second part of this thesis, I investigate the implications of these mechanisms - that explain edge formation in social networks - on machine learning. Specifically, I study the influence of homophily, preferential attachment, edge density, fraction of inorities, and the directionality of links on both performance and bias of collective classification, and on the visibility of minorities in top-k ranks. My findings demonstrate a strong correlation between network structure and machine learning outcomes. This suggests that systematic discrimination against certain people can be: (i) anticipated by the type of network, and (ii) mitigated by connecting strategically in the network.

Developing a Voxel Classifier using High Angular Resolution Diffusion Data (2012)

Engelhardt, Sandy

Magnetic resonance (MR) tomography is an imaging method, that is used to expose the structure and function of tissues and organs in the human body for medical diagnosis. Diffusion weighted (DW) imaging is a specific MR imaging technique, which enables us to gain insight into the connectivity of white matter pathways noninvasively and in vivo. It allows for making predictions about the structure and integrity of those connections. In clinical routine this modality finds application in the planning phase of neurosurgical operations, such as in tumor resections. This is especially helpful if the lesion is deeply seated in a functionally important area, where the risk of damage is given. This work reviews the concepts of MR imaging and DW imaging. Generally, at the current resolution of diffusion weighted data, single white matter axons cannot be resolved. The captured signal rather describes whole fiber bundles. Beside this, it often appears that different complex fiber configurations occur in a single voxel, such as crossings, splittings and fannings. For this reason, the main goal is to assist tractography algorithms who are often confound in such complex regions. Tractography is a method which uses local information to reconstruct global connectivities, i.e. fiber tracts. In the course of this thesis, existing reconstruction methods such as diffusion tensor imaging (DTI) and q-ball imaging (QBI) are evaluated on synthetic generated data and real human brain data, whereas the amount of valuable information provided by the individual reconstruction mehods and their corresponding limitations are investigated. The output of QBI is the orientation distribution function (ODF), where the local maxima coincides with the underlying fiber architecture. We determine those local maxima. Furthermore, we propose a new voxel-based classification scheme conducted on diffusion tensor metrics. The main contribution of this work is the combination of voxel-based classification, local maxima from the ODF and global information from a voxel- neighborhood, which leads to the development of a global classifier. This classifier validates the detected ODF maxima and enhances them with neighborhood information. Hence, specific asymmetric fibrous architectures can be determined. The outcome of the global classifier are potential tracking directions. Subsequently, a fiber tractography algorithm is designed that integrates along the potential tracking directions and is able to reproduce splitting fiber tracts.

Formal Integration of Individual Knowledge Work and Organizational Knowledge Work with the Core Ontology strukt (2011)

Eißing, Daniel ; Scherp, Ansgar ; Staab, Steffen

Expert-driven business process management is an established means for improving efficiency of organizational knowledge work. Implicit procedural knowledge in the organization is made explicit by defining processes. This approach is not applicable to individual knowledge work due to its high complexity and variability. However, without explicitly described processes there is no analysis and efficient communication of best practices of individual knowledge work within the organization. In addition, the activities of the individual knowledge work cannot be synchronized with the activities in the organizational knowledge work.rnrnSolution to this problem is the semantic integration of individual knowledgernwork and organizational knowledge work by means of the patternbased core ontology strukt. The ontology allows for defining and managing the dynamic tasks of individual knowledge work in a formal way and to synchronize them with organizational business processes. Using the strukt ontology, we have implemented a prototype application for knowledge workers and have evaluated it at the use case of an architectural fifirm conducting construction projects.

Integration of Existing Multimedia Metadata Formats and Metadata Standards in the M3O (2010)

Eißing, Daniel ; Scherp, Ansgar ; Saathoff, Carsten

With the Multimedia Metadata Ontology (M3O), we have developed a sophisticated model for representing among others the annotation, decomposition, and provenance of multimedia metadata. The goal of the M3O is to integrate the existing metadata standards and metadata formats rather than replacing them. To this end, the M3O provides a scaffold needed to represent multimedia metadata. Being an abstract model for multimedia metadata, it is not straightforward how to use and specialize the M3O for concrete application requirements and existing metadata formats and metadata standards. In this paper, we present a step-by-step alignment method describing how to integrate and leverage existing multimedia metadata standards and metadata formats in the M3O in order to use them in a concrete application. We demonstrate our approach by integrating three existing metadata models: the Core Ontology on Multimedia (COMM), which is a formalization of the multimedia metadata standard MPEG-7, the Ontology for Media Resource of the W3C, and the widely known industry standard EXIF for image metadata

Profile-based selection of answer candidates for LogAnswer (2012)

Eifler, Timo

In dieser Ausarbeitung beschreibe ich die Ergebnisse meiner Untersuchungen zur Erweiterung des LogAnswer-Systemsmit nutzerspezifischen Profilinformationen. LogAnswer ist ein natürlichsprachliches open-domain Frage-Antwort-System. Das heißt: es beantwortet Fragen zu beliebigen Themen und liefert dabei konkrete (möglichst knappe und korrekte) Antworten zurück. Das System wird im Rahmen eines Gemeinschaftsprojekts der Arbeitsgruppe für künstliche Intelligenz von Professor Ulrich Furbach an der Universität Koblenz-Landau und der Arbeitsgruppe Intelligent Information and Communication Systems (IICS) von Professor Hermann Helbig an der Fernuniversität Hagen entwickelt. Die Motivation meiner Arbeit war die Idee, dass der Prozess der Antwortfindung optimiert werden kann, wenn das Themengebiet, auf das die Frage abzielt, im Vorhinein bestimmt werden kann. Dazu versuchte ich im Rahmen meiner Arbeit die Interessensgebiete von Nutzern basierend auf Profilinformationen zu bestimmen. Das Semantic Desktop System NEPOMUK wurde verwendet um diese Profilinformationen zu erhalten. NEPOMUK wird verwendet um alle Daten, Dokumente und Informationen, die ein Nutzer auf seinem Rechner hat zu strukturieren. Dazu nutzt das System ein sogenanntes Personal Information Model (PIMO) in Form einer Ontologie. Diese Ontologie enthält unter anderem eine Klasse "Topic", welche die wichtigste Grundlage für das Erstellen der in meiner Arbeit verwendeten Nutzerprofile bildete. Konkret wurde die RDF-Anfragesprache SPARQL verwendet, um eine Liste aller für den Nutzer relevanten Themen aus der Ontologie zu filtern. Die zentrale Idee meiner Arbeit war es nun diese Profilinformationen zur Optimierung des Ranking von Antwortkandidaten einzusetzen. In LogAnswer werden zu jeder gestellten Frage bis zu 200 potentiell relevante Textstellen aus der deutschen Wikipedia extrahiert. Diese Textstellen werden auf Basis von Eigenschaften (wie z.B. lexikalische Übereinstimmungen zwischen Frage und Textstelle) geordnet, da innerhalb des zur Verfügung stehenden Zeitlimits nicht alle Kandidaten bearbeitet werden können. Mein Ansatz verfolgte das Ziel, diesen Algorithmus durch Nutzerprofile so zu erweitern, dass Antwortkandidaten, welche für den Benutzer relevante Informationen enthalten, höher in der Rangfolge eingeordnet werden. Zur Umsetzung dieser Idee musste eine Methode gefunden werden, um zu bestimmen ob ein Antwortkandidat mit dem Profil übereinstimmt. Da sich die in einer Textstelle enthaltenen Informationen in den meisten Fällen auf das übergeordnete Thema des Artikels beziehen, ohne den Namen des Artikels explizit zu erwähnen, wurde in meiner Implementierung der Artikelname betrachtet, um zu ermitteln, zu welchem Themengebiet die Textstelle Informationen liefert. Als zusätzliches Hilfsmittel wurde außerdem die DBpedia-Ontologie eingesetzt, welche die Informationen der Wikipedia strukturiert im RDF Format enthält. Mit Hilfe dieser Ontologie war es möglich, jeden Artikel in Kategorien einzuordnen, die dann mit den im Profil enthaltenen Stichworten verglichen wurden. Zur Untersuchung der Auswirkungen des Ansatzes auf das Ranking-Verfahren wurden mehrere Testläufe mit je 200 Testfragen durchgeführt. Die erste Testmenge bestand aus zufällig ausgewählten Fragen, die mit meinem eigenen Nutzerprofil getestet wurden. Dieser Testlauf lieferte kaum nutzbare Ergebnisse, da nur bei 29 der getesteten Fragen überhaupt ein Antwortkandidat mit dem Profil in Verbindung gebracht werden konnte. Außerdem konnte eine potentielle Verbesserung der Ergebnisse nur bei einer dieser 29 Fragen festgestellt werden, was zu der Schlussfolgerung führte, dass der Einsatz von Profildaten nicht für Anwendungsfälle geeignet ist, in denen die Fragen keine Korrelation mit dem genutzten Profil aufweisen. Da die Grundannahme meiner Arbeit war, dass Nutzer in erster Linie Fragen zu den Interessensgebieten stellen, welche sich aus ihrem Profil ableiten lassen, sollten die weiteren Testläufe genau diesen Fall beleuchten. Dazu wurden 200 Testfragen aus dem Bereich Sport ausgewählt und mit einem Profil getestet, welches Stichworte zu unterschiedlichen Sportarten enthielt. Die Tests mit den Sportfragen waren wesentlich aussagekräftiger. Auch hier deuteten die Ergebnisse darauf hin, dass der Ansatz kein großes Potential zur Verbesserung des Rankings hat. Eine genauere Betrachtung einiger ausgewählter Beispiele zeigte allerdings, dass die Integration von Profildaten für bestimmte Anwendungsfälle, wie z.B. offene Fragen für die es mehr als eine korrekte Antwort gibt, durchaus zu einer Verbesserung der Ergebnisse führen kann. Außerdem wurde festgestellt, dass viele der schlechten Ergebnisse auf Inkosistenzen in der DBpedia-Ontologie und grundsätzliche Probleme im Umgang mit Wissensbasen in natürlicher Sprache beruhen. Die Schlussfolgerung meiner Arbeit ist, dass der in dieser Arbeit vorgestellte Ansatz zur Integration von Profilinformationen für den aktuellen Anwendungsfall von LogAnswer nicht geeignet ist, da vor allem Faktenwissen aus sehr unterschiedlichen Domänen abgefragt wird und offene Fragen nur einen geringen Anteil ausmachen.

A first proposal for an overall structure of an enhanced reality framework (2007)

Ebert, Jürgen ; Falkowski, Kerstin

The term "Augmented Reality (AR)" denotes the superposition of additional virtual objects and supplementary information over real images. The joint project Enhanced Reality (ER)1 aims at a generic AR-system. The ER-project is a cooperation of six different research groups of the Department of Computer Science at the University of Koblenz-Landau. According to Ronald Azuma an AR-system combines real and virtual environments, where the real and virtual objects are registered in 3-D, and it provides interactivity in real time [Azu97]. Enhanced Reality extends Augmented Reality by requiring the virtual objects to be seamlessly embedded into the real world as photo-realistic objects according to the exact lighting conditions. Furthermore, additional information supplying value-added services may be displayed and interaction of the user may even be immersive. The short-term goal of the ER-project is the exploration of ER-fundamentals using some specific research scenarios; the long-term goal is the development of a component-based ER-framework for the creation of ER-applications for arbitrary application areas. ER-applications are developed as single-user applications for users who are moving in a real environment and are wearing some kind of visual output device like see-through glasses and some mobile end device. By these devices the user is able to see reality as it is, but he can also see the virtual objects and the additional information about some value-added service. Furthermore he might have additional devices whereby he can interact with the available virtual objects. The development of a generic framework for ER-applications requires the definition of generic components which are customizable and composable to build concrete applications and it requires a homogeneous data model which supports all components equally well. The workgroup "Software Technology"2 is responsible for this subproject. This report gives some preliminary results concerning the derivation of a component-based view of ER. There are several augmented reality frameworks like ARVIKA, AMIRE, DWARF, MORGAN, Studierstube and others which offer some support for the development of AR-applications. All of them ease the use of existing subsystems like AR-Toolkit, OpenGL and others and leverage the generation process for realistic systems by making efficient use of those subsystems. Consequently, they highly rely on them.

Enterprise Content Management - Archiving of Enterprise 2.0 data (2012)

Dammenhayn, Nils

Regarding the rapidly growing amount of data produced every year and the increasing acceptance of Enterprise 2.0 enterprises have to care about the management of their data more and more. Content created and stored in an uncoordinated manner can lead to data-silos (Williams & Hardy 2011, p.57), which result in long search times, inaccessible data and in consequence monetary losses. The "expanding digital universe" forces enterprises to develop new archiving solutions and records management policies (Gantz et al. 2007, p.13). Enterprise Content Management (ECM) is the research field that deals with these challenges. It is placed in the scientific context of Enterprise Information Management. This thesis aims to find out to what extent current Enterprise Content Management Systems (ECMS) support these new requirements, especially concerning the archiving of Enterprise 2.0 data. For this purpose, three scenarios were created to evaluate two different kinds of ECMS (one Open Source - and one proprietary system) chosen on the basis of a short marketrnresearch. The application of the scenarios reveals that the system vendors actually face the industry- concerns: both tools provide functionality for the archiving of data arising from online collaboration and also business records management capabilities but the integration of those topics is not, or is only inconsistently solved. At this point new questions - such as, "Which datarngenerated in an Enterprise 2.0 is worth being a record?" - arise and should be examined in future research.

Concept for a Knowledge Base on ICT for Governance and Policy Modelling regarding eGovPoliNet (2013)

Bär, Dominic

Abstract The EU project eGovPoliNet is engaged in research and development in the field of information and communication technologies (ICT) for governance and policy modelling. Numerous communities pursue similar goals in this field of IT-based, strategic decision making and simulation of social problem areas. Though, the existing research approaches and results so far are quite fragmented. The aim of eGovPoliNet is to overcome the fragmentation across disciplines and to establish an international, open dialogue by fostering the cooperation between research and practice. This dialogue will advance the discussion and development of various problem areas with the help of researchers from different disciplines, who share knowledge, expertise and best practice supporting policy analysis, modelling and governance. To support this dialogue, eGovPoliNet will provide a knowledge base, which's conceptual development is the subject of this thesis. The knowledge base is to be filled with content from the area of ICT for strategic decision making and social simulation, such as publications, ICT solutions and project descriptions. This content needs to be structured, organised and managed in a way, so that it generates added value and the knowledge base is used as source of accumulated knowledge, which consolidates the previously fragmented research and development results in a central location. The aim of this thesis is the development of a concept for a knowledge base, which provides the structure and the necessary functionalities to gather and process knowledge concerning ICT solutions for governance and policy modelling. This knowledge needs to be made available to users and thereby motivate them to contribute to the development and maintenance of the knowledge base.

Face and Gaze Controlled Onscreen Presentations (FAGCOP) (2020)

Bukhari, Syed Nabil Afaraz

On-screen interactive presentations have got immense popularity in the domain of attentive interfaces recently. These attentive screens adapt their behavior according to the user's visual attention. This thesis aims to introduce an application that would enable these attentive interfaces to change their behavior not just according to the gaze data but also facial features and expressions. The modern era requires new ways of communications and publications for advertisement. These ads need to be more specific according to people's interests, age, and gender. When advertising, it's important to get a reaction from the user but not every user is interested in providing feedback. In such a context more, advance techniques are required that would collect user's feedback effortlessly. The main problem this thesis intends to resolve is, to apply advanced techniques of gaze and face recognition to collect data about user's reactions towards different ads being played on interactive screens. We aim to create an application that enables attentive screens to detect a person's facial features, expressions, and eye gaze. With eye gaze data we can determine the interests and with facial features, age and gender can be specified. All this information will help in optimizing the advertisements.

Collaborative creation of semantic points of interest as linked data on the mobile phone (2010)

Braun, Max ; Scherp, Ansgar ; Staab, Steffen

The novel mobile application csxPOI (short for: collaborative, semantic, and context-aware points-of-interest) enables its users to collaboratively create, share, and modify semantic points of interest (POI). Semantic POIs describe geographic places with explicit semantic properties of a collaboratively created ontology. As the ontology includes multiple subclassiffcations and instantiations and as it links to DBpedia, the richness of annotation goes far beyond mere textual annotations such as tags. With the intuitive interface of csxPOI, users can easily create, delete, and modify their POIs and those shared by others. Thereby, the users adapt the structure of the ontology underlying the semantic annotations of the POIs. Data mining techniques are employed to cluster and thus improve the quality of the collaboratively created POIs. The semantic POIs and collaborative POI ontology are published as Linked Open Data.

RoboCup 2008 Mixed Reality League Team Description (2008)

Bohnen, Matthias ; Brühl, Lina ; Bzdak, Sebastian ; Effert, Carsten ; Freidank, Martin ; Großmann, Eckhard ; Habelitz, Thorsten ; Koch, Andreas ; Mann, David ; Sdorra, Bastian ; Abert, Oliver ; Maron, Markus

The University of Koblenz-Landau would like to apply for participation in the RoboCup Mixed Reality League in Suzhou, China 2008. Our team is composed of ten team members and two supervisors. All members are graduate students of Computational Visualistics. Our supervisors are Ph.D. candidates currently researching in the working groups of artificial intelligence and computer graphics.

Avoidance of routing loops (2009)

Bohdanowicz, Frank ; Dickel, Harald ; Steigner, Christoph

We introduce a new routing algorithm which can detect routing loops by evaluating routing updates more thoroughly. Our new algorithm is called Routing with Metric based Topology Investigation (RMTI), which is based on the simple Routing Information Protocol (RIP) and is compatible to all RIP versions. In case of a link failure, a network can reorganize itself if there are redundant links available. Redundant links are only available in a network system like the internet if the topology contains loops. Therefore, it is necessary to recognize and to prevent routing loops. A routing loop can be seen as a circular trace of a routing update information which returns to the same router, either directly from the neighbor router or via a loop topology. Routing loops could consume a large amount of network bandwidth and could impact the endtoend performance of the network. Our RMTI approach is capable to improve the efficiency of Distance Vector Routing.

E-Hyper Tableaux with Distinct Object Identifiers (2013)

Bender, Markus

E-KRHyper is a versatile theorem prover and model generator for firstorder logic that natively supports equality. Inequality of constants, however, has to be given by explicitly adding facts. As the amount of these facts grows quadratically in the number of these distinct constants, the knowledge base is blown up. This makes it harder for a human reader to focus on the actual problem, and impairs the reasoning process. We extend E-Hyper- underlying E-KRhyper tableau calculus to avoid this blow-up by implementing a native handling for inequality of constants. This is done by introducing the unique name assumption for a subset of the constants (the so called distinct object identifiers). The obtained calculus is shown to be sound and complete and is implemented into the E-KRHyper system. Synthetic benchmarks, situated in the theory of arrays, are used to back up the benefits of the new calculus.

Extending the E-Hyper Tableau Calculus for Reasoning with the Unique Name Assumption (2012)

Bender, Markus

In automated theorem proving, there are some problems that need information on the inequality of certain constants. In most cases this information is provided by adding facts which explicitly state that two constants are unequal. Depending on the number of constants, a huge amount of this facts can clutter the knowledge base and distract the author and readers of the problem from its actual proposition. For most cases it is save to assume that a larger knowledge base reduces the performance of a theorem prover, which is another drawback of explicit inequality facts. Using the unique name assumption in those reasoning tasks renders the introduction of inequality facts obsolete as the unique name assumptions states that two constants are identical iff their interpretation is identical. Implicit handling of non-identical constants makes the problems easier to comprehend and reduces the execution time of reasoning. In this thesis we will show how to integrate the unique name assumption into the E-hyper tableau calculus and that the modified calculus is sound and complete. The calculus will be implemented into the E-KRHyper theorem prover and we will show, by empiric evaluation, that the changed implementation, which is able to use the unique name assumption, is superior to the traditional version of E-KRHyper.

Local area navigation for multi-axle vehicles using machine learning algorithms (2013)

Barthen, Andreas

This thesis describes the implementation of a Path-planning algorithm for multi-axle vehicles using machine learning algorithms. For that purpose, a general overview over Genetic Algorithms is given and alternative machine learning algorithms are briefly explained. The software developed for this purpose is based on the EZSystem Simulation Software developed by the AG Echtzeitysteme at the University Koblenz-Landau and a path correction algorithm developed by Christian Schwarz, which is also detailed in this paper. This also includes a description of the vehicle used in these simulations. Genetic Algorithms as a solution for path-planning in complex scenarios are then evaluated based on the results of the developed simulation software and compared to alternative, non-machine learning solutions, which are also shortly presented.

Adding formal semantics to MPEG-7 (2007)

Arndt, Richard ; Staab, Steffen ; Troncy, Raphael ; Hardman, Lynda

Semantic descriptions of non-textual media available on the web can be used to facilitate retrieval and presentation of media assets and documents containing them. While technologies for multimedia semantic descriptions already exist, there is as yet no formal description of a high quality multimedia ontology that is compatible with existing (semantic) web technologies. We explain the complexity of the problem using an annotation scenario. We then derive a number of requirements for specifying a formal multimedia ontology, including: compatibility with MPEG-7, embedding in foundational ontologies, and modularisation including separation of document structure from domain knowledge. We then present the developed ontology and discuss it with respect to our requirements.

Tests and proofs: papers presented at the Second International Conference TAP 2008, Prato, Italy, April 2008 (2008)

This volume contains those research papers presented at the Second International Conference on Tests and Proofs (TAP 2008) that were not included in the main conference proceedings. TAP was the second conference devoted to the convergence of proofs and tests. It combines ideas from both areas for the advancement of software quality. To prove the correctness of a program is to demonstrate, through impeccable mathematical techniques, that it has no bugs; to test a program is to run it with the expectation of discovering bugs. On the surface, the two techniques seem contradictory: if you have proved your program, it is fruitless to comb it for bugs; and if you are testing it, that is surely a sign that you have given up on any hope of proving its correctness. Accordingly, proofs and tests have, since the onset of software engineering research, been pursued by distinct communities using rather different techniques and tools. And yet the development of both approaches leads to the discovery of common issues and to the realization that each may need the other. The emergence of model checking has been one of the first signs that contradiction may yield to complementarity, but in the past few years an increasing number of research efforts have encountered the need for combining proofs and tests, dropping earlier dogmatic views of their incompatibility and taking instead the best of what each of these software engineering domains has to offer. The first TAP conference (held at ETH Zurich in February 2007) was an attempt to provide a forum for the cross-fertilization of ideas and approaches from the testing and proving communities. For the 2008 edition we found the Monash University Prato Centre near Florence to be an ideal place providing a stimulating environment. We wish to sincerely thank all the authors who submitted their work for consideration. And we would like to thank the Program Committee members as well as additional referees for their great effort and professional work in the review and selection process. Their names are listed on the following pages. In addition to the contributed papers, the program included three excellent keynote talks. We are grateful to Michael Hennell (LDRA Ltd., Cheshire, UK), Orna Kupferman (Hebrew University, Israel), and Elaine Weyuker (AT&T Labs Inc., USA) for accepting the invitation to address the conference. Two very interesting tutorials were part of TAP 2008: "Parameterized Unit Testing with Pex" (J. de Halleux, N. Tillmann) and "Integrating Verification and Testing of Object-Oriented Software" (C. Engel, C. Gladisch, V. Klebanov, and P. Rümmer). We would like to express our thanks to the tutorial presenters for their contribution. It was a team effort that made the conference so successful. We are grateful to the Conference Chair and the Steering Committee members for their support. And we particularly thank Christoph Gladisch, Beate Körner, and Philipp Rümmer for their hard work and help in making the conference a success. In addition, we gratefully acknowledge the generous support of Microsoft Research Redmond, who financed an invited speaker.

RoboCup 2019 – homer@UniKoblenz (Germany) (2019)

This paper describes the robots TIAGo and Lisa used by team homer@UniKoblenz of the University of Koblenz-Landau, Germany, for the participation at the RoboCup@Home 2019 in Sydney, Australia. We ended up first at RoboCup@Home 2019 in the Open Platform League and won the competition in our league now three times in a row (four times in total) which makes our team the most successful in RoboCup@Home. We demonstrated approaches for learning from demonstration, touch enforcing manipulation and autonomous semantic exploration in the finals. A special focus is put on novel system components and the open source contributions of our team. We have released packages for object recognition, a robot face including speech synthesis, mapping and navigation, speech recognition interface, gesture recognition and imitation learning. The packages are available (and new packages will be released) on http://homer.uni-koblenz.de.

RoboCup 2018 – homer@UniKoblenz (Germany) (2018)

This paper describes the robots TIAGo and Lisa used by team homer@UniKoblenz of the University of Koblenz-Landau, Germany, for the participation at the RoboCup@Home 2018 in Montreal, Canada. Further this paper serves as qualification material for the RoboCup-@Home participation in 2018. A special focus is put on novel system components and the open source contributions of our team. This year the team from Koblenz won the biggest annual scientianc robot competition in Montreal in the RoboCup@Home Open Platform track for the third time and also won the RoboCup@Home German Open for the second time. As a research highlight a novel symbolic imitation learning approach was demonstrated during the annals. The TIAGo robotic research platform was used for the first time by the team. We have released packages for object recognition, a robot face including speech synthesis, mapping and navigation, speech recognition interface via android and a GUI. The packages are available (and new packages will be released) on http://wiki.ros.org/agas-ros-pkg. Further information can be found on our project page http://homer.uni-koblenz.de.

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