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In der heutigen Robotik-Forschung soll hauptsächlich die Interaktion von autonomen, mobilen Robotern mit vorher nicht bekannten Umgebungen ermöglicht werden. Eines der grundlegendsten Probleme, das in diesem Kontext gelöst werden muss, ist die Frage, wo der Roboter ist und wie seine Umgebung in unmittelbarer Nähe, aber auch an bereits besuchten Orten aussieht " das sogenannte SLAM Problem.
In dieser Arbeit wird ein GraphSLAM System vorgestellt, das einen graphbasierten Lösungsansatz für dieses Problem darstellt. Ein solches System besteht aus einem Frontend und einem Backend. Das Frontend hat die Aufgabe, aus den Sensordaten einen Graphen zu konstruieren, der die relative Lage der Messungen zueinander widerspiegelt. Da sich Messungen widersprechen können, ist ein solcher Graph im Allgemeinen inkonsistent. Das Backend hat nun die Aufgabe, diesen Graphen zu optimieren, d. h. eine Konfiguration der Knoten zu bestimmen, die sich nur minimal widerspricht. Knoten repräsentieren Roboterposen, die aufgrund der enthaltenen Rotationen sog. Mannigfaltigkeiten sind und keinen gewöhnlichen Vektorraum bilden. Dies wird in der Arbeit konsequent berücksichtigt, was zu einem sehr effizienten und eleganten Optimierungsverfahren führt.
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.
Aktuell stehen nur wenige Informationen über die Verbreitung von Cloud Computing in deutschen Hochschulen zur Verfügung. Ein besseres Verständnis vom Stand der Technik in diesem Bereich würde die Modernisierung der Hochschulen in Deutschland und die Entwicklung von geeigneteren Cloud Produkten und neuen Geschäftsmodellen für diese Nische ermöglichen. Zu diesem Zweck wird eine Literaturrecherche über Cloud Computing und IT-Verbreitung und eine empirische Untersuchung mit einem Online-Fragebogen an Hochschulen in Deutschland durchgeführt, um den aktuellen Stand von Cloud Computing an deutschen Hochschulen zu untersuchen.
Ebenso fragt die Untersuchung nach den Chancen und Risiken, die die Mitarbeiterinnen und Mitarbeiter von Hochschulrechenzentren bei der Nutzung von Cloud Computing sehen. Im Anschluss daran werden Experten aus Universitäten und Unternehmen interviewt, um die gesammelten Informationen vom Online-Fragebogen und während der Forschung zu erweitern. Die erwarteten Ergebnisse werden dazu dienen, um eine Empfehlung für Hochschulen in Deutschland zu verfassen, ob sie Cloud Technologien schon benutzen sollen oder nicht. Darüber hinaus wird eine Liste mit kritischen Leitfragen vorgestellt, die vor der Migration zum Cloud Computing berücksichtig werden sollte.
In der vorliegenden Arbeit untersuche ich eine breite Spanne von Libraries, Frameworks und anderer Technologien für die Programmiersprache Haskell. Ich demonstriere verschiedene praktische Anwendungen von Haskell und trage durch Implementationen und Taxonomieeinheiten zum 101companies System bei. Dies tue ich, indem ich einen großen Teil des 101companies feature models abdecke und damit verknüpfte Definitionen von Begriffen und Technologien in dieses System einpflege. Die Implementationen zeigen, wie verschiedene Sprachkonzepte von Haskell wie ein sehr starkes Typensystem, Polymorphismus, Funktionen höherer Ordnungen und Monaden effektiv bei der Entwicklung von Informationssystemen benutzt werden können. In diesem Zusammenhang zeige ich sowohl Vorteile als auch Einschränkungen der verschiedenen Technologien auf.
Distanzvektor-Routing-Protokolle sind Interior-Gateway-Protokolle, bei denen jeder Router anhand der Informationen, die er von seinen Nachbarn erhält, eine Routingtabelle mit den kürzesten Wegen und dazugehörigen Kosten zu allen anderen Routern des Netzwerks aufbaut. Distanzvektor-Routing-Protokolle sehen jedoch nur unzureichende Mechanismen vor, um die Sicherheit ihrer Operationen zu gewährleisten. Es wird vielmehr einfach davon ausgegangen, dass die Umgebung vertrauenswürdig ist. Router können sich aber aus verschiedenen Gründen böswillig verhalten und falsche Routingupdates einschleusen um das Routing zu manipulieren. Authentizität und Integrität der übermittelten Routinginformationen müssen daher sichergestellt werden; dabei soll eine Balance zwischen Nutzen und Performance gefunden werden.
Diese Arbeit untersucht verschiedene Lösungsansätze, die sich die Erfüllung dieser Anforderungen zum Ziel gesetzt haben, und stellt deren Vor- und Nachteile einander gegenüber.
Cloud Computing is a topic that has gained momentum in the last years. Current studies show that an increasing number of companies is evaluating the promised advantages and considering making use of cloud services. In this paper we investigate the phenomenon of cloud computing and its importance for the operation of ERP systems. We argue that the phenomenon of cloud computing could lead to a decisive change in the way business software is deployed in companies. Our reference framework contains three levels (IaaS, PaaS, SaaS) and clarifies the meaning of public, private and hybrid clouds. The three levels of cloud computing and their impact on ERP systems operation are discussed. From the literature we identify areas for future research and propose a research agenda.
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.
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.
Die Identifizierung von wiederverwendbarem Source-Code für die Implementierung von SOA Services ist noch immer ein ungelöstes Problem. Diese Masterarbeit beschreibt einen Ansatz zur Identifizierung von Legacy-Code, der für eine Service-Implementierung geeignet ist. Der Ansatz basiert auf dynamischer Analyse und dem Einsatz von Data Mining Techniken. Im Rahmen des SOAMIG Projekts wurden durch dynamische Analyse Geschäftsprozesse auf Source- Code abgebildet. Der große Umfang der daraus resultierenden Traces macht eine Nachbearbeitung der Ergebnisse notwendig. In dieser Masterarbeit wurde die Anwendbarkeit von Data Mining Techniken zur Nachbearbeitng der dynamischen Traces untersucht. Zwei Data Mining Verfahren, Cluster-Analyse und Link- Analyse, wurden auf die dynamischen Traces einer Java/Swing Beispielsoftware angewendet. Die Ergebnisse deuten auf eine gute Verwendbarkeit der beiden Data Mining Techniken zur Identifizierung von Legacy-Code für die Service-Implementierung hin.
MapReduce with Deltas
(2011)
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.
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.
In dieser Arbeit werden vier der derzeit verfügbaren webbasierten Visualisierungstools evaluiert (FlexViz, Jambalaya applet, Experimental jOWL TouchGraph, Plone ontology).
Im Rahmen dieser Arbeit werden weiterhin folgende Fragen erforscht: 1. Welche Anforderungen an die Visualisierung von Ontologien können definiert werden? 2. Wie kann eine Bewertung und Analyse durchgeführt werden? 3. Wie kann eine ausgewählte Methode getestet werden? Basierend auf den Ergebnissen dieser Fragestellungen stellte sich die Visualisierungsmethode FlexViz im gegebenen Szenario als beste heraus. FlexViz wurde eingesetzt, indem es in das Content Management System Plone integriert wurde. Es wurde mit VCD Ontologien getestet und schließlich aus der Sicht verschiedener Interessengruppen analysiert. Es zeigte sich, dass FlexViz ein gutes Tool zum Visualisieren, Verstehen und Analysieren von bereits entwickelten Ontologien ist, da die Benutzeroberfläche benutzerfreundlich und interaktiv ist. Jedoch zeigt FlexViz deutliche Schwächen bzgl. dem Bearbeiten, Erweitern und Entwickeln von Ontologien.
API Migration bezeichnet den Wechsel einer benutzten API eines Programms in eine andere. Eine spezielle Form ist die sogenannte wrapper-basierte API Migration. In diesem Fall wird die API gewechselt, ohne das eigentliche Programm zu berühren. Sie wird unter Benutzung der neuen API reimplementiert. Dieser so genannte Wrapper besitzt das Interface der alten API, benutzt jedoch die Implementierung der neuen.
Dies ist ein interessanter Ansatz, da der Wrapper in jedem Programm eingesetzt werden kann, das bislang die alte API verwendet hat.
Um diesen Vorgang reproduzierbar zu machen, entwickeln wir eine ranking-basierte Methode, um einen Wrapper zu entwickeln. Hierbei implementieren wir abhängig von fehlschlagenden Testfällen immer die API-Methode mit der jeweils höchsten Priorität. So können wir jeden Implementierungssschritt rekonstruieren.
Im ersten Schritt entwickeln wir eine Infrastruktur, mit der wir Testsuites von Java-Projekten starten und messen können.
Mittels dieser Basis können wir nun die Ranking-Methode anweden, um einen Wrapper zu entwickeln.
In dieser Arbeit wird ein skelettbasiertes Matching-Verfahren für 2D-Objekte vorgestellt. Zunächst werden aktuelle Ansätze zum Matchen von Objekten vorgestellt, anschließend werden die Grundlagen von skelettbasiertem Matching erklärt. Ein skelettbasiertes Verfahren wurde im Rahmen dieser Arbeit gemäß dem vorliegenden Original-Paper neu implementiert. Diese Implementierung wird anhand einer Ähnlichkeitssuche in drei Bild-Datenbanken evaluiert. Stärken und Schwächen des Verfahrens werden herausgearbeitet. Des weiteren wird der vorgestellte Algorithmus auf Erweiterungen untersucht, die das Matchen von 3D-Objekten ermöglichen sollen. Im speziellen wird das Verfahren auf medizinische Daten angewendet: CT-Aufnahmen der abdominalen Aorta eines Patienten vor und nach einer Operation werden miteinander verglichen. Problemfälle und Erweiterungsansätze für das Matchen von 3D-Objekten im Allgemeinen und von Blutgefäßen im Speziellen werden vorgestellt.
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.
As Enterprise 2.0 (E2.0) initiatives are gradually moving out of the early experimentation phase it is time to focus greater attention on examining the structures, processes and operations surrounding E2.0 projects. In this paper we present the findings of an empirical study to investigate and understand the reasons for initiating E2.0 projects and the benefits being derived from them. Our study comprises seven in-depth case studies of E2.0 implementations. We develop a classification and means of visualising the scope of E2.0 initiatives and use these methods to analyse and compare projects.
Our findings indicate a wide range of motivations and combinations of technology in use and show a strong emphasis towards the content management functionality of E2.0 technologies.
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.
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.
Diese Bachelorarbeit beschäftigt sich mit dem Vergleich bezüglich der Ähnlichkeit von aufgezeichneten WLAN-Mustern bei der Nachverfolgung eines Pfades durch die Straßen einer großen Stadt. Sowohl ein nur auf MAC-Adressen basierender Vergleich als auch die Miteinbeziehung von RSSI-Werten ist untersucht worden, wobei die Lokalisierungsgenauigkeit bewertet wurde. Methoden für die Erkennung unterschiedlicher Typen und Kombinationen von Schleifen in dem Pfad werden gezeigt, ebenso wie der Versuch, den Grad urbaner Bebauung in der Umgebung des Benutzers abzuschätzen, indem die empfangene Signalstärke und der Signal-Rausch-Abstand von GPS-Satelliten und GSM-Funkmasten ausgewertet wurde.
Um die Annäherung eines Benutzers an einen bestimmten Punkt auf einem großen öffentlichen Platz zu beobachten, wurde die Absorption von WLAN-Signalen durch den menschlichen Körper berücksichtigt. Abschließend werden die Ergebnisse eines Vergleichs zwischen der Rechenleistung eines modernen Smartphones und der Alternative einer entfernten Berechnung auf einem Server inklusive der Datenübertragung über das Mobilfunknetz vorgestellt.
Designing Core Ontologies
(2011)
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.
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.
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.
The estimation of various social objects is necessary in different fields of social life, science, education, etc. This estimation is usually used for forecasting, for evaluating of different properties and for other goals in complex man-machine systems. At present this estimation is possible by means of computer and mathematical simulation methods which is connected with significant difficulties, such as: - time-distributed process of receiving information about the object; - determination of a corresponding mathematical device and structure identification of the mathematical model; - approximation of the mathematical model to real data, generalization and parametric identification of the mathematical model; - identification of the structure of the links of the real social object. The solution of these problems is impossible without a special intellectual information system which combines different processes and allows predicting the behaviour of such an object. However, most existing information systems lead to the solution of only one special problem. From this point of view the development of a more general technology of designing such systems is very important. The technology of intellectual information system development for estimation and forecasting the professional ability of respondents in the sphere of education can be a concrete example of such a technology. Job orientation is necessary and topical in present economic conditions. It helps tornsolve the problem of expediency of investments to a certain sphere of education. Scientifically validated combined diagnostic methods of job orientation are necessary to carry out professional selection in higher education establishments. The requirements of a modern society are growing, with the earlier developed techniques being unable to correspond to them sufficiently. All these techniques lack an opportunity to account all necessary professional and personal characteristics. Therefore, it is necessary to use a system of various tests. Thus, the development of new methods of job orientation for entrants is necessary. The information model of the process of job orientation is necessary for this purpose. Therefore, it would be desirable to have an information system capable of giving recommendations concerning the choice of a trade on the basis of complex personal characteristics of entrants.
Knowledge compilation is a common technique for propositional logic knowledge bases. A given knowledge base is transformed into a normal form, for which queries can be answered efficiently. This precompilation step is expensive, but it only has to be performed once. We apply this technique to concepts defined in the Description Logic ALC. We introduce a normal form called linkless normal form for ALC concepts and discuss an efficient satisability test for concepts given in this normal form. Furthermore, we will show how to efficiently calculate uniform interpolants of precompiled concepts w.r.t. a given signature.
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.
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
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.
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.
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.
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.
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.
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.
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.
An empirical study to evaluate the location of advertisement panels by using a mobile marketing tool
(2009)
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.
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.
In recent years, traceability has been more and more universally accepted as being a key factor for the success of software development projects. However, the multitude of different, not well-integrated taxonomies, approaches and technologies impedes the application of traceability techniques in practice. This paper presents a comprehensive view on traceability, pertaining to the whole software development process. Based on graph technology, it derives a seamless approach which combines all activities related to traceability information, namely definition, recording, identification, maintenance, retrieval, and utilization in one single conceptual framework. The presented approach is validated in the context of the ReDSeeDS-project aiming at requirements-based software reuse.
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.
Avoidance of routing loops
(2009)
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.
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 and—if so—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.
Social networking platforms as creativity fostering systems: research model and exploratory study
(2008)
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.
Querying for meta knowledge
(2008)
The Semantic Web is based on accessing and reusing RDF data from many different sources, which one may assign different levels of authority and credibility. Existing Semantic Web query languages, like SPARQL, have targeted the retrieval, combination and reuse of facts, but have so far ignored all aspects of meta knowledge, such as origins, authorship, recency or certainty of data, to name but a few. In this paper, we present an original, generic, formalized and implemented approach for managing many dimensions of meta knowledge, like source, authorship, certainty and others. The approach re-uses existing RDF modeling possibilities in order to represent meta knowledge. Then, it extends SPARQL query processing in such a way that given a SPARQL query for data, one may request meta knowledge without modifying the query proper. Thus, our approach achieves highly flexible and automatically coordinated querying for data and meta knowledge, while completely separating the two areas of concern.
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.
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.
CAMPUS NEWS - artificial intelligence methods combined for an intelligent information network
(2008)
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.