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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.
Folksonomies are Web 2.0 platforms where users share resources with each other. Furthermore, they can assign keywords (called tags) to the resources for categorizing and organizing the resources. Numerous types of resources like websites (Delicious), images (Flickr), and videos (YouTube) are supported by different folksonomies. The folksonomies are easy to use and thus attract the attention of millions of users. Together with the ease they offer, there are also some problems. This thesis addresses different problems of folksonomies and proposes solutions for these problems. The first problem occurs when users search for relevant resources in folksonomies. Often, the users are not able to find all relevant resources because they don't know which tags are relevant. The second problem is assigning tags to resources. Although many folksonomies (like Delicious) recommend tags for the resources, other folksonomies (like Flickr) do not recommend any tags. Tag recommendation helps the users to easily tag their resources. The third problem is that tags and resources are lacking semantics. This leads for example to ambiguous tags. The tags are lacking semantics because they are freely chosen keywords. The automatic identification of the semantics of tags and resources helps in reducing problems that arise from this freedom of the users in choosing the tags. This thesis proposes methods which exploit semantics to address the problems of search, tag recommendation, and the identification of tag semantics. The semantics are discovered from a variety of sources. In this thesis, we exploit web search engines, online social communities and the co-occurrences of tags as sources of semantics. Using different sources for discovering semantics reduces the efforts to build systems which solve the problems mentioned earlier. This thesis evaluates the proposed methods on a large scale data set. The evaluation results suggest that it is possible to exploit the semantics for improving search, recommendation of tags, and automatic identification of the semantics of tags and resources.
One task of executives and project managers in IT companies or departments is to hire suitable developers and to assign them to suitable problems. In this paper, we propose a new technique that directly leverages previous work experience of developers in a systematic manner. Existing evidence for developer expertise based on the version history of existing projects is analyzed. More specifically, we analyze the commits to a repository in terms of affected API usage. On these grounds, we associate APIs with developers and thus we assess API experience of developers. In transitive closure, we also assess programming domain experience.
Social media provides a powerful way for people to share opinions and sentiments about a specific topic, allowing others to benefit from these thoughts and feelings. This procedure generates a huge amount of unstructured data, such as texts, images, and references that are constantly increasing through daily comments to related discussions. However, the vast amount of unstructured data presents risks to the information-extraction process, and so decision making becomes highly challenging. This is because data overload may cause the loss of useful data due to its inappropriate presentation and its accumulation. To this extent, this thesis contributed to the field of analyzing and detecting feelings in images and texts. And that by extracting the feelings and opinions hidden in a huge collection of image data and texts on social networks After that, these feelings are classified into positive, negative, or neutral, according to the features of the classified data. The process of extracting these feelings greatly helps in decision-making processes on various topics as will be explained in the first chapter of the thesis. A system has been built that can classify the feelings inherent in the images and texts on social media sites, such as people’s opinions about products and companies, personal posts, and general messages. This thesis begins by introducing a new method of reducing the dimension of text data based on data-mining approaches and then examines the sentiment based on neural and deep neural network classification algorithms. Subsequently, in contrast to sentiment analysis research in text datasets, we examine sentiment expression and polarity classification within and across image datasets by building deep neural networks based on the attention mechanism.
Ein Switch (engl. Schalter; auch Weiche) ist eine Netzwerk-Komponente zur Verbindung mehrerer Computer bzw. Netz-Segmente in einem lokalen Netzwerk (LAN). Da Switches den Netzwerkverkehr analysieren und logische Entscheidungen treffen, werden sie auch als intelligente Hubs bezeichnet. Die Funktionsweise eines Switches ist der einer Bridge sehr ähnlich, daher wurde anfangs auch der Begriff Multi-Port-Bridge genutzt 1. Ziel der Diplomarbeit ist es, eine Dokumentation auf die Beine zu stellen, der interessierten Studenten der Informationstechnologie die Möglichkeit bietet, einerseits anhand von physikalischen Switches Administrationsaufgaben nachzuempfinden und andererseits anhand von virtuellen Switches größere Netzwerktopologien aufzubauen. Diese Virtualisierung wird durch das von Virtual Square entwickelte Tool VDE erreicht. Die physikalischen Switches bestehen aus vier Catalyst 3500 XL. Im Laufe dieser Arbeit wird sowohl die Bedienung der einzelnen Systeme untereinander, wie auch die Vernetzung der virtuellen Switches mit den physikalischen Switches erläutert. In diesem Zusammenhang wird auch auf Protokolle und Methoden wie das Spanning Tree Protokoll oder die Virtualisierung eines Netzes durch VLANs eingegangen. Zum Schluss kann der Leser das gelernte in einigen praktischen Aufgaben anwenden.
Rechnernetze gehört zu den Fächern, die ein breites Spektrum an Anwendungsgebieten abdecken. Die vielen unterschiedlichen Protokolle sind Belege dafür. Jedes Protokoll hat sozusagen ein eigenes Anwendungsbereich und doch sind deren Aufgaben unter dem Nenner gleich. Miteinander zu Kommunizieren, Informationen auszutauschen und das möglichst auf eine sichere und schnelle Art und Weise. Als Beispiel denke man an Autos, Handys, Lokale Netze in einem kleinen Betrieb, Intranet in einer größeren Organisation oder in Netze die über Länder hinweggehen. Ein modernes Auto an sich hat schon eine Vielzahl an Bussystemen in sich integriert. CAN, LIN, FlexRay oder MOST Bus sind ein paar Stichworte dazu. Wenn man jetzt von der Autoindustrie weggeht und an die Autonomen Systeme kommt, gibt es dort ein Routing Information Protokoll, das innerhalb von Autonomen Systemen verwendet wird. Routing Information Protokoll ist eines der meist verwendeten Protokolle innerhalb von Autonomen Systemen. Das Routing Information Protokoll ist einer der zentralen Bestandteile des Forschungsbereiches der AG Steigner. Die Arbeit widmet sich unter Anderem dieser Forschungsunterstützung.Diese Studienarbeit hat das Ziel die Testumgebung XTPeer auf die VNUML Version 1.8 zu integrieren.
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.
We aim to demonstrate that automated deduction techniques, in particular those following the model computation paradigm, are very well suited for database schema/query reasoning. Specifically, we present an approach to compute completed paths for database or XPath queries. The database schema and a query are transformed to disjunctive logic programs with default negation, using a description logic as an intermediate language. Our underlying deduction system, KRHyper, then detects if a query is satisfiable or not. In case of a satisfiable query, all completed paths -- those that fulfill all given constraints -- are returned as part of the computed models. The purpose of our approach is to dramatically reduce the workload on the query processor. Without the path completion, a usual XML query processor would search the database for solutions to the query. In the paper we describe the transformation in detail and explain how to extract the solution to the original task from the computed models. We understand this paper as a first step, that covers a basic schema/query reaÂsoning task by model-based deduction. Due to the underlying expressive logic formalism we expect our approach to easily adapt to more sophisticated problem settings, like type hierarchies as they evolve within the XML world.
Hyper tableaux with equality
(2007)
In most theorem proving applications, a proper treatment of equational theories or equality is mandatory. In this paper we show how to integrate a modern treatment of equality in the hyper tableau calculus. It is based on splitting of positive clauses and an adapted version of the superposition inference rule, where equations used for paramodulation are drawn (only) from a set of positive unit clauses, the candidate model. The calculus also features a generic, semantically justified simplification rule which covers many redundancy elimination techniques known from superposition theorem proving. Our main results are soundness and completeness, but we briefly describe the implementation, too.
The Living Book is a system for the management of personalized and scenario specific teaching material. The main goal of the system is to support the active, explorative and selfdetermined learning in lectures, tutorials and self study. The Living Book includes a course on 'logic for computer scientists' with a uniform access to various tools like theorem provers and an interactive tableau editor. It is routinely used within teaching undergraduate courses at our university. This paper describes the Living Book and the use of theorem proving technology as a core component in the knowledge management system (KMS) of the Living Book. The KMS provides a scenario management component where teachers may describe those parts of given documents that are relevant in order to achieve a certain learning goal. The task of the KMS is to assemble new documents from a database of elementary units called 'slices' (definitions, theorems, and so on) in a scenario-based way (like 'I want to prepare for an exam and need to learn about resolution'). The computation of such assemblies is carried out by a model-generating theorem prover for first-order logic with a default negation principle. Its input consists of meta data that describe the dependencies between different slices, and logic-programming style rules that describe the scenario-specific composition of slices. Additionally, a user model is taken into account that contains information about topics and slices that are known or unknown to a student. A model computed by the system for such input then directly specifies the document to be assembled. This paper introduces the elearning context we are faced with, motivates our choice of logic and presents the newly developed calculus used in the KMS.
The model evolution calculus
(2004)
The DPLL procedure is the basis of some of the most successful propositional satisfiability solvers to date. Although originally devised as a proof procedure for first-order logic, it has been used almost exclusively for propositional logic so far because of its highly inefficient treatment of quantifiers, based on instantiation into ground formulas. The recent FDPLL calculus by Baumgartner was the first successful attempt to lift the procedure to the first-order level without resorting to ground instantiations. FDPLL lifts to the first-order case the core of the DPLL procedure, the splitting rule, but ignores other aspects of the procedure that, although not necessary for completeness, are crucial for its effectiveness in practice. In this paper, we present a new calculus loosely based on FDPLL that lifts these aspects as well. In addition to being a more faithful litfing of the DPLL procedure, the new calculus contains a more systematic treatment of universal literals, one of FDPLL's optimizations, and so has the potential of leading to much faster implementations.
Cheops für VNUML - Erstellen und beobachten einer VNUML-Simulation per MausklickrnEs wird untersucht, wie Virtual Network User Mode Linux (VNUML), eine Software zur Simulation von Rechnernetzen, die aus virtualisierten Linux Instanzen aufgebaut werden, für den Benutzer besser handhabbar gemacht werden kann. Mit dem Linux-Paket VNUML, welches die dateigesteuerte Konfiguration virtueller Betriebssysteminstanzen ermöglicht, erhält der Anwender die Möglichkeit, komplexe Netzwerktopologien zu simulieren. Verschiedene Netzwerküberwachungsprogramme werden auf ihre Fähigkeit hin untersucht, eine laufende VNUML-Simulation zu erfassen und sinnvoll abzubilden. Dabei soll der Benutzer einen schnellen Überblick über die Funktion der simulierten Netzwerkumgebung, sowie nach Möglichkeit auch über deren Topologie erhalten können. Das Programm Cheops, welches der Netzwerküberwachung dient, wird erweitert, um nicht nur eine laufende Simulation abbilden und beobachten zu können, sondern darüber hinaus in der Lage zu sein, in jedem Schritt der Arbeit mit VNUML eingesetzt zu werden.
Das erweiterte Programm gestattet sowohl die Erstellung der VNUML-Topologiedatei, als auch das Starten und Steuern der Simulation. Damit werden der lange Kommandozeilenaufruf, sowie das Editieren der Konfigurationsdatei, durch einfach zu benutzende Funktionen in einer grafischen Oberfläche (GUI) ersetzt. Zur schnellen Kontrolle der vollen Funktionsfähigkeit der gestarteten Simulation sind keine weiteren Eingaben oder Konfigurationen nötig. Ebenso kann eine differenzierte Beobachtung verschiedener Netzwerkdienste während der Laufzeit der Simulation erfolgen. Die hierzu nötigen Werkzeuge sind im Paket Cheops für VNUML ebenfalls enthalten und speziell zur Anwendung mit VNUML-Simulationen vorkonfiguriert.
This minor thesis shows a way to optimise a generated oracle to achieve shorter runtimes. Shorter runtimes of test cases allows the execution of more test cases in the same time. The execution of more test cases leads to a higher confidence in the software-quality. Oracles can be derived from specifications. However specifications are used for different purposes and therefore are not necessarily executable. Even if the are executable it might be with only a high runtime. Those two facts come mostly from the use of quantifiers in the logic. If the quantifier-range is not bounded, respectively if the bounds are outside the target language-datatype-limits, the specification is too expressive to be exported into a program. Even if the bounds inside the used datatype-limits, the quantification is represented as a loop which leads to a runtime blowup, especially if quantifiers are nested. This work explains four different possibilities to reduce the execution time of the oracle by manipulating the quantified formular whereas this approach is only applicable if the quantified variables are of type Integer.
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.
This dissertation introduces a methodology for formal specification and verification of user interfaces under security aspects. The methodology allows to use formal methods pervasively in the specification and verification of human-computer interaction. This work consists of three parts. In the first part, a formal methodology for the description of human-computer interaction is developed. In the second part, existing definitions of computer security are adapted for human-computer interaction and formalized. A generic formal model of human-computer interaction is developed. In the third part, the methodology is applied to the specification and verification of a secure email client.
Das Routing Information Protocol (RIP) ist ein Internet-Standard-Routing-Protokoll, das einst mit zu den am meisten eingesetzten Routing-Protokollen in IP-Netzwerken gehörte. Es basiert auf dem sogenannten Distanzvektoralgorithmus und ist in seiner Funktion und seinem Aufbau sehr einfach ausgelegt. Seit jeher leidet es allerdings unter dem sogenannten Counting-to-Infinity (CTI) Problem, bei dem die Erreichbarkeit einer eigentlich ausgefallenen Verbindung zu einem Ziel scheinbar aufrechterhalten wird. Die Distanz zu diesem Ziel wird aufgrund des fortwährenden Austauschs von nicht mehr gültigen Verbindungsinformationen zwischen in einem Ring geschalteten RIP-Routern hochgezählt, theoretisch bis ins Unendliche. Dabei entstehen Routingschleifen, die den Netzwerkbetrieb erheblich stören können, da die gesendeten Netzwerkpakete aufgrund der Schleife die selben Router immer wieder passieren und weder an ihr eigentliches Ziel gelangen noch verworfen werden können. Die Gefahr des Auftretens des CTI-Problems schränkt die Einsetzbarkeit von RIP enorm ein. Die Netzwerke, in denen RIP eingesetzt wird, können nicht beliebig wachsen, da die maximale Größe des Netzwerks auf eine relativ kleine Distanz zwischen den Routern begrenzt ist, um die Dauer und die Folgen des CTI-Problems im Falle des Auftretens gering zu halten. Je stärker auch die Topologie eines Netzwerks vermascht ist, um mit zusätzlichen, alternativen Verbindungen Ausfällen entgegenzuwirken, umso stärker steigt auch die Gefahr des Auftretens des CTI-Problems nach einem Ausfall. Bislang existierten für RIP lediglich Mechanismen, die das Risiko des Auftretens und die Auswirkungen des CTI-Problems verringern, das Problem selbst aber nicht beheben können. Mit "RIP with minimal topology information" (RIP-MTI) wurde in der AG Rechnernetze an der Universität Koblenz-Landau eine abwärtskompatible Erweiterung zu RIP geschaffen, die das CTI-Problem zu beheben verspricht. Der RIP-MTI-Algorithmus sammelt zusätzliche Informationen über die Topologie des Netzwerks und nutzt diese, um nach dem Ausfall einer Verbindung richtige Informationen über die Erreichbarkeit von Zielen von falschen Informationen unterscheiden zu können. In dieser Diplomarbeit wird die Implementierung des RIP-MTI-Algorithmus behandelt. Mit Hilfe der speziell entwickelten RIP-Netzwerk-Testumgebung XTPeer, in der das CTI-Problem kontrolliert provoziert werden kann, wird die Wirksamkeit der Implementierung eines Quagga RIP-MTI-Routers überprüft und entsprechend weiterentwickelt. Dafür wird der RIP-MTI-Algorithmus an die Implementierung des Quagga RIP-Routing-Software sowie an die der Netzwerk-Testumgebung XTPeer angepasst. Diese Diplomarbeit wird vom Autor selbst als fortgeschrittene Zwischenstation eingestuft, vor der Herstellung und Herausgabe der Implementierung einer RIP-MTI-Routing-Software, die auch in produktiven Netzwerken eingesetzt werden könnte.
SNMP in VNUML Simulationen
(2007)
Das Simple Network Management Protocol (SNMP) gilt als die Universalsprache des Netzwerkmanagements. Bereits Anfang der 90er Jahre wurde die erste Version von SNMP durch die Internet Engineering Task Force (IETF) zum Standard-Internet Management Protocol erklärt und Teil der TCP/IP Protocol-Suite. Für die meisten Betriebssystemplattformen sind SNMP Implementierungen verfügbar und viele netzwerkfähige Geräte und Netzwerkmanagement-Programme unterstützen SNMP, das sich vor allem für die Verwaltung plattformübergreifender und herstellerunabhängiger Netzwerke bewährt. Virtual Network User Mode Linux (VNUML) ist ein mächtiges Netzwerk-Simulationsprogramm für Linux mit dem virtuelle Linux-Rechnernetze aufgebaut werden können, um darin Programmabläufe zu simulieren. Die VNUML Netzwerk-Simulationen sind in erster Linie für das Entwickeln, Analysieren und Testen von Linux Netzwerk-Software, wie zum Beispiel Netzwerk-Protokollen, geeignet. Das Simulationsprogramm entstand im Rahmen des Euro6IX-Projektes, zur Einführung des IPv6 Standards in Europa, am Telematics Engineering Department der Technischen Universität Madrid. Die Rechner der virtuellen Netze, die VNUML aufbaut, basieren auf User Mode Linux (UML), einer in breitem Spektrum eingesetzten Virtualisierung des Linux-Kernels. Diese Studienarbeit beschäftigt sich mit den Möglichkeiten und der Funktionsweise des Netzwerkmanagements mit SNMP. Dafür wird die SNMP-Software Net-SNMP in VNUML Simulationen eingesetzt, um die Möglichkeiten der Konfiguration und des Umgangs mit SNMP in einer praxisnahen Umgebung zu untersuchen. Der Einsatz von Net-SNMP in VNUML Simulationen kann dazu dienen, die Integration von Netzwerkmanagement mit SNMP für relevante Rechnernetze vorzubereiten und Möglichkeiten der Konfiguration und der Verwendung auszuloten oder VNUML Simulationen im Allgemeinen mit diesem bewährten Netzwerkmanagement-System zur Unterstützung auszustatten.
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.
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.
This thesis proposes the use of MSR (Mining Software Repositories) techniques to identify software developers with exclusive expertise about specific APIs and programming domains in software repositories. A pilot Tool for finding such
“Islands of Knowledge” in Node.js projects is presented and applied in a case study to the 180 most popular npm packages. It is found that on average each package has 2.3 Islands of Knowledge, which is possibly explained by the finding that npm packages tend to have only one main contributor. In a survey, the maintainers of 50 packages are contacted and asked for opinions on the results produced by the Tool. Together with their responses, this thesis reports on experiences made with the pilot Tool and how future iterations could produce even more accurate statements about programming expertise distribution in developer teams.
Die Arbeitsgruppe Echtzeitsysteme an der Universität Koblenz beschäftigt sich seit mehreren Jahren mit der Thematik autonomes und assistiertes Fahren. Eine große Herausforderung stellen in diesem Zusammenhang mehrgliedrige Fahrzeuge dar, deren Steuerung für den Fahrer während der Rückwärtsfahrt sehr anspruchsvoll ist. Um präzise Manöver zu ermöglichen, können elektronische Fahrerassistenzsysteme zum Einsatz kommen. Im Rahmen vorhergehender Arbeiten sind bereits einige Prototypen entstanden, von denen jedoch keiner eine geeignete Lösung für moderne, zweiachsige Anhänger darstellt. Im Rahmen dieser Arbeit wurde ein prototypisches Fahrerassistenzsystem entwickelt, wobei es noch weiterer Forschungs- und Entwicklungsarbeit bedarf, um das System straßentauglich zu machen.
Skalierbarkeit und garantierte Ausliererung sind essentielle Eigenschaften eines jeden Routingalgorithmus. Beides bietet bei drahtlosen Ad-hoc Netzwerken die Kombination aus Greedy- und Face- Routing, sofern ein planarer Graph zur Verfügung steht. Doch gerade die fehlerfreie Planarisierung bereitet bei realistischen Netzwerken Schwierigkeiten. Daher soll mit dieser Arbeit die Frage beantwortet werden, zu welcher Fehlerrate es führt, wenn der Graph lediglich mit lokalen Methoden teilplanarisiert wird. Dazu wurde eine Simulationsumgebung geschaffen, um unter Anwendung des Log-Normal-Shadowing-Modells zufällige Konnektivitätsgraphen zu generieren. Diese wurden anschließend durch zwei unterschiedliche, lokale Strategien teilplanarisiert. Es wurden neun verschiedene Settings definiert, die sich aus drei unterschiedlichen Graphendichten und drei unterschiedlichen Werten für den Sigmaparameter des Log-Normal-Shadowing-Modells ergeben. Für jedes Setting wurde in 2000 Simulationsdurchläufen das Verhalten von Greedy-, Face- und kombiniertem Greedy-Face-Routing untersucht und ausgewertet. Zum Abschluss wurden die Ergebnisse dieser Simulation bewertet und diskutiert.
Motion capture refers to the process of capturing, processing and trans- lating real motions onto a 3D model. Not only in the movie and gaming industries, motion capture creates an indispensable realism of human and animal movement. Also in the context of robotics, medical movement therapy, as well as in AR and VR, motion capture is used extensively. In addition to the well established optical processes, especially in the last three areas, alternative systems based on inertial navigation (IMUs) are being used in-creasingly, because they do not rely on external cameras and thus limit the area of movement considerably less.
Fast evolving technical progress in the manufacturing of such IMUs allows building small sensors, wearable on the body which can transfer movements to a computer. The development of applying inertial systems to a motion capture context, however, is still at an early state. Problems like drift can currently only be minimized by adding additional hardware for correcting the read data.
In the following master thesis an IMU based motion capture system is designed and constructed. This contains the assembly of the hardware components as well as processing of the received movement data on the software side and their application to a 3D model.
Im Rahmen von Projekten haben die Mitarbeiter in einem Unternehmen oft komplexe Problemstellungen zu bearbeiten, für die es keine objektiv richtigen oder falschen Lösungen gibt. Stattdessen werden im Rahmen der Entwurfs- und Entscheidungsprozesse mehrere Lösungsvorschläge erarbeitet um dann unter Abwägung von Pro- und Contra-Argumenten eine möglichst optimale Lösung zu finden.
This Work analyzes if a hardware prototype on an Arduino basis for an Adhoc Network can be created. The objective of the prototype development is, the creation of a sensor node with a modular design, where components can be easily changed. Furthermore the application area has requirements, which the node must fulfill. These requirements are derived from the Tmote Sky sensor node, therefore the new created sensor node must be a possible alternative for it and fulfill the same functions. For that purpose this study reviews some available Arduino microprocessors on their suitability for a sensor node. Later in the work the composition of the sensor node is documented. For this, the hardware and their costs are illustrated. The created hardware prototype allows, through easily changed radio modules, the covering of 433 MHz, 866 MHz and 2,40 GHz radio frequencies. At the end of the work, the sensor node prototype is used in an experiment to check for the suitability for water monitoring. For this, an experiment was performed on land and on water and the results evaluated. In the end the prototype fulfilled most of the requirements, but the cost was a little too high.
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.
Diese Arbeit behandelt verschiedene Ansätze zur Ermittlung einer Heuristik, welche zur Bestimmung einer optimalen Konfiguration des Theorembeweisers E-KRHyper eingesetzt werden soll. Es wird erläutert, wie der Beweiser durch eine angepasste Voreinstellung optimiert werden kann und die erarbeiteten Ansätze zur Ermittlung dieser Voreinstellung werden vorgestellt. Anhand der erzielten Ergebnisse werden die Ansätze anschließend bewertet und für eines der vorgestellten Verfahren wird außerdem eine Idee zur Implementierung vorgestellt.
Diese Studienarbeit soll eine Einführung in die Arbeit mit virtual network user mode linux (VNUML) geben. Mit Hilfe dieser Arbeit möchte ich speziell die Version VNUML 1.6 näher bringen und die wesentlichen Unterschiede, Vor- und Nachteile zur Version 1.5 zeigen. In den nächsten zwei Kapiteln wird auf das Thema VNUML und UML oberflächlich eingegangen. Das darauffolgende Kapitel befasst sich mit der Installation von VNUML 1.6, der Vorraussetzung und den möglichen Fehlermeldungen. Wenn dies abgeschlossen ist, wird VNUML 1.6 mit eigenen Beispielen ausfürlich, praktisch und theoretisch vorgestellt. Danach werden die wesentlichen Unterschiede von VNUML 1.5 zu VNUML 1.6 beschrieben. Zum Abschluss sind noch ein Kapitel mit kurzen Begriffsdefinitionen und der Anhang mit allen XML-Dateien zu finden. Auf den Aufbau einer XML-Datei möchte ich in meiner Arbeit nicht weiter eingehen. Dazu verweise ich auf die Arbeit von Thomas Chmielowiec und Tim Keupen. In diesen Arbeiten sind die XML-Syntax und Semantik ausfürlich beschrieben.
This thesis introduces fnnlib, a C++ library for recurrent neural network simulations that I developed between October 2009 and March 2010 at Osaka University's Graduate School of Engineering. After covering the theory behind recurrent neural networks, backpropagation through time, recurrent neural networks with parametric bias, continuous-time recurrent neural networks, and echo state networks, the design of the library is explained. All of the classes as well as their interrelationships are presented along with reasons as to why certain design decisions were made. Towards the end of the thesis, a small practical example is shown. Also, fnnlib is compared to other neural network libraries.
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.
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.
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.
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.
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.
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.
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.
So far VNUML (Virtual Network User Mode Linux) has been used by the group for Computer Networks at the University of Koblenz in such a way as to test its own protocol enhancement for RIP (Routing Information Protocol) on strengths and weaknesses. The modified version of RIP is called RMTI (RIP with minimal topology information). In particular, special test scenarios have been used to investigate wether a Count-to-Infinity (CTI) problem can be completely avoided and how quickly the network converges after the failure or breakdown of a router. Tius thesis investigates whether the MTI enhancement also provides for better performance in larger networks. Furthermore, it will be investigated if it is worth using the script tool EDIV ((spanish: Escenarios DIstribuidos con VNUML, english: Distributed Scenarios using VNUML) due to its enhanced scalability and whether the distribution of an XML scenario on several computers has a significant impact on the convergence time. Apart from simulations, test scenarios will be developed and tested in order to generate results about the efficiency and scalability of the Distance Vector Routing Protocol.
Connected vehicles will have a tremendous impact on tomorrow’s mobility solutions. Such systems will heavily rely on information delivery in time to ensure the functional reliability, security and safety. However, the host-centric communication model of today’s networks questions efficient data dissemination in a scale, especially in networks characterized by a high degree of mobility. The Information-Centric Networking (ICN) paradigm has evolved as a promising candidate for the next generation of network architectures. Based on a loosely coupled communication model, the in-network processing and caching capabilities of ICNs are promising to solve the challenges set by connected vehicular systems. In such networks, a special class of caching strategies which take action by placing a consumer’s anticipated content actively at the right network nodes in time are promising to reduce the data delivery time. This thesis contributes to the research in active placement strategies in information-centric and computation-centric vehicle networks for providing dynamic access to content and computation results. By analyzing different vehicular applications and their requirements, novel caching strategies are developed in order to reduce the time of content retrieval. The caching strategies are compared and evaluated against the state-of-the-art in both extensive simulations as well as real world deployments. The results are showing performance improvements by increasing the content retrieval (availability of specific data increased up to 35% compared to state-of-the-art caching strategies), and reducing the delivery times (roughly double the number of data retrieval from neighboring nodes). However, storing content actively in connected vehicle networks raises questions regarding security and privacy. In the second part of the thesis, an access control framework for information-centric connected vehicles is presented. Finally, open security issues and research directions in executing computations at the edge of connected vehicle networks are presented.
Education and training of the workforce have become an important competitive factor for companies because of the rapid technological changes in the economy and the corresponding ever shorter innovation cycles. Traditional training methods, however, are limited in terms of meeting the resulting demand for education and training in a company, which continues to grow and become faster all the time. Therefore, the use of technology-based training programs (that is, courseware) is increasing because courseware enables self-organized and self-paced learning and, through integration into daily work routines, allows optimal transfer of knowledge and skills, resulting in high learning outcome. To achieve these prospects, high-quality courseware is required, with quality being defined as supporting learners optimally in achieving their learning goals. Developing high-quality courseware, however, usually requires more effort and takes longer than developing other programs, which limits the availability of this courseware in time and with the required quality.
This dissertation therefore deals with the research question of how courseware has to be developed in order to produce high-quality courseware with less development effort and shorter project duration. In addition to its high quality, this courseware should be optimally aligned to the characteristics and learning goals of the learners as well as to the planned usage scenarios for the knowledge and skills being trained. The IntView Method for the systematic and efficient development of high-quality courseware was defined to answer the research question of this dissertation. It aims at increasing the probability of producing courseware in time without exceeding project schedules and budgets while developing a high-quality product optimally focused on the target groups and usage scenarios.
The IntView Methods integrates those execution variants of all activities and activity steps required to develop high-quality courseware, which were identified in a detailed analysis of existing courseware development approaches as well as production approaches from related fields, such as multimedia, web, or software engineering, into a systematic process that in their interaction constitute the most efficient way to develop courseware. The main part of the proposed method is therefore a systematic process for engineering courseware that encompasses all courseware lifecycle phases and integrates the activities and methods of all disciplines involved in courseware engineering, including a lifecycle encompassing quality assurance, into a consolidated process. This process is defined as a lifecycle model as well as a derived process model in the form of a dependency model in order to optimally support courseware project teams in coordinating and synchronizing their project work. In addition to the models, comprehensive, ready-to-apply enactment support materials are provided, consisting of work sheets and document templates that include detailed activity descriptions and examples.
The evaluation of the IntView Method proved that the method together with the enactment support materials enables efficient as well as effective courseware development. The projects and case studies conducted in the context of this evaluation demonstrate that, on the one hand, the method is easily adaptable to the production of different kinds of courseware or to different project contexts, and, on the other hand, that it can be used efficiently and effectively.
The publication of freely available and machine-readable information has increased significantly in the last years. Especially the Linked Data initiative has been receiving a lot of attention. Linked Data is based on the Resource Description Framework (RDF) and anybody can simply publish their data in RDF and link it to other datasets. The structure is similar to the World Wide Web where individual HTML documents are connected with links. Linked Data entities are identified by URIs which are dereferenceable to retrieve information describing the entity. Additionally, so called SPARQL endpoints can be used to access the data with an algebraic query language (SPARQL) similar to SQL. By integrating multiple SPARQL endpoints it is possible to create a federation of distributed RDF data sources which acts like one big data store.
In contrast to the federation of classical relational database systems there are some differences for federated RDF data. RDF stores are accessed either via SPARQL endpoints or by resolving URIs. There is no coordination between RDF data sources and machine-readable meta data about a source- data is commonly limited or not available at all. Moreover, there is no common directory which can be used to discover RDF data sources or ask for sources which offer specific data. The federation of distributed and linked RDF data sources has to deal with various challenges. In order to distribute queries automatically, suitable data sources have to be selected based on query details and information that is available about the data sources. Furthermore, the minimization of query execution time requires optimization techniques that take into account the execution cost for query operators and the network communication overhead for contacting individual data sources. In this thesis, solutions for these problems are discussed. Moreover, SPLENDID is presented, a new federation infrastructure for distributed RDF data sources which uses optimization techniques based on statistical information.
Using semantic data from general-purpose programming languages does not provide the unified experience one would want for such an application. Static error checking is lacking, especially with regards to static typing of the data. Based on the previous work of λ-DL, which integrates semantic queries and concepts as types into a typed λ-calculus, this work takes its ideas a step further to meld them into a real-world programming language. This thesis explores how λ-DL's features can be extended and integrated into an existing language, researches an appropriate extension mechanism and produces Semantics4J, a JastAdd-based Java language semantic data extension for type-safe OWL programming, together with examples of its usage.
Im Rahmen dieser Arbeit soll eine Methodik erarbeitet werden, die englische, keyword-basierte Anfragen in SPARQL übersetzt und bewertet. Aus allen generierten SPARQL-Queries sollen die relevantesten ermittelt und ein Favorit bestimmt werden. Das Ergebnis soll in einer Nutzerevaluation bewertet werden.
Location Provider
(2011)
In dieser Arbeit wurde gemäß den in Kapitel 1.3 definierten Anforderungen ein System entwickelt, um mobile und in der Rechenleistung beschränkte Geräte wie Mobiltelefone und PDAs sowohl im Freien als auch in geschlossenen Räumen verorten zu können. Der eingeschränkten Leistungsfähigkeit der Geräte wird durch die Umsetzung einer Client-Server Lösung Rechnung getragen, bei der der Client als Sensorträger dient, der Daten aus seiner Umgebung registriert und über ein Kommunikationsnetz zur weiteren Berechnung an einen Server überträgt. Die Datenübertragung ist als Webservice realisiert, der auf offenen Standards wie XML und SOAP basiert und leicht um weitere Funktionen erweitert werden kann.
For software engineers, conceptually understanding the tools they are using in the context of their projects is a daily challenge and a prerequisite for complex tasks. Textual explanations and code examples serve as knowledge resources for understanding software languages and software technologies. This thesis describes research on integrating and interconnecting
existing knowledge resources, which can then be used to assist with understanding and comparing software languages and software technologies on a conceptual level. We consider the following broad research questions that we later refine: What knowledge resources can be systematically reused for recovering structured knowledge and how? What vocabulary already exists in literature that is used to express conceptual knowledge? How can we reuse the
online encyclopedia Wikipedia? How can we detect and report on instances of technology usage? How can we assure reproducibility as the central quality factor of any construction process for knowledge artifacts? As qualitative research, we describe methodologies to recover knowledge resources by i.) systematically studying literature, ii.) mining Wikipedia, iii.) mining available textual explanations and code examples of technology usage. The theoretical findings are backed by case studies. As research contributions, we have recovered i.) a reference semantics of vocabulary for describing software technology usage with an emphasis on software languages, ii.) an annotated corpus of Wikipedia articles on software languages, iii.) insights into technology usage on GitHub with regard to a catalog of pattern and iv.) megamodels of technology usage that are interconnected with existing textual explanations and code examples.
This paper documents the development of an abstract physics layer (APL) for Simspark. After short introductions to physics engines and Simspark, reasons why an APL was developed are explained. The biggest part of this paper describes the new design and why certain design choices were made based on requirements that arose during developement. It concludes by explaining how the new design was eventually implemented and what future possibilities the new design holds.
In unserer heutigen Welt spielen soziale Netzwerke eine immer größere werdende Rolle. Im Internet entsteht fast täglich eine neue Anwendung in der Kategorie Web 2.0. Aufgrund dieser Tatsache wird es immer wichtiger die Abläufe in sozialen Netzwerken zu verstehen und diese für Forschungszwecke auch simulieren zu können. Da alle gängigen sozialen Netzwerke heute nur im eindimensionalen Bereich arbeiten, beschäftigt sich diese Diplomarbeit mit mehrdimensionalen sozialen Netzwerken. Mehrdimensionale soziale Netzwerke bieten die Möglichkeit verschiedene Beziehungsarten zu definieren. Beispielsweise können zwei Akteure nicht nur in einer "kennt"-Beziehung stehen, sondern diese Beziehungsart könnte auch in diverse Unterbeziehungsarten, wie z.B. Akteur A "ist Arbeitskollege von" Akteur B oder Akteur C "ist Ehepartner von" Akteur D, unterteilt werden. Auf diese Art und Weise können beliebig viele, völlig verschiedene Beziehungsarten nebeneinander existieren. Die Arbeit beschäftigt sich mit der Frage, in welchem Grad die Eigenschaften von eindimensionalen auch bei mehrdimensionalen sozialen Netzwerken gelten. Um das herauszufinden werden bereits bestehende Metriken weiterentwickelt. Diese Metriken wurden für eindimensionale soziale Netzwerke entwickelt und können nun auch für die Bewertung mehrdimensionaler sozialer Netzwerke benutzt werden. Eine zentrale Fragestellung ist hierbei wie gut sich Menschen finden, die sich etwas zu sagen haben. Um möglichst exakte Ergebnisse zu erhalten, ist es notwendig reale Daten zu verwenden. Diese werden aus einem Web 2.0-Projekt, in das Benutzer Links zu verschiedenen Themen einstellen, gewonnen (siehe Kapitel 4). Der erste praktische Schritte dieser Arbeit besteht daher darin, das soziale Netzwerk einzulesen und auf diesem Netzwerk eine Kommunikation, zwischen zwei Personen mit ähnlichen Themengebieten, zu simulieren. Die Ergebnisse der Simulation werden dann mit Hilfe der zuvor entwicklelten Metriken ausgewertet.
The amount of information on the Web is constantly increasing and also there is a wide variety of information available such as news, encyclopedia articles, statistics, survey data, stock information, events, bibliographies etc. The information is characterized by heterogeneity in aspects such as information type, modality, structure, granularity, quality and by its distributed nature. The two primary techniques by which users on the Web are looking for information are (1) using Web search engines and (2) browsing the links between information. The dominant mode of information presentation is mainly static in the form of text, images and graphics. Interactive visualizations offer a number of advantages for the presentation and exploration of heterogeneous information on the Web: (1) They provide different representations for different, very large and complex types of information and (2) large amounts of data can be explored interactively using their attributes and thus can support and expand the cognition process of the user. So far, interactive visualizations are still not an integral part in the search process of the Web. The technical standards and interaction paradigms to make interactive visualization usable by the mass are introduced only slowly through standardatization organizations. This work examines how interactive visualizations can be used for the linking and search process of heterogeneous information on the Web. Based on principles in the areas of information retrieval (IR), information visualization and information processing, a model is created, which extends the existing structural models of information visualization with two new processes: (1) linking of information in visualizations and (2) searching, browsing and filtering based on glyphs. The Vizgr toolkit implements the developed model in a web application. In four different application scenarios, aspects of the model will be instantiated and are evaluated in user tests or examined by examples.
Interactive video retrieval
(2006)
The goal of this thesis is to develop a video retrieval system that supports relevance feedback. One research approach of the thesis is to find out if a combination of implicit and explicit relevance feedback returns better retrieval results than a system using explicit feedback only. Another approach is to identify a model to weight existing feature categories. For this purpose, a state-of-the-art analysis is presented and two systems implemented, which run under the conditions of the international TRECVID workshop. It will be a basis system for further research approaches in the field of interactive video retrieval. Amongst others, it shall participate in the 2006 search task of the mentioned workshop.
Empirical studies in software engineering use software repositories as data sources to understand software development. Repository data is either used to answer questions that guide the decision-making in the software development, or to provide tools that help with practical aspects of developers’ everyday work. Studies are classified into the field of Empirical Software Engineering (ESE), and more specifically into Mining Software Repositories (MSR). Studies working with repository data often focus on their results. Results are statements or tools, derived from the data, that help with practical aspects of software development. This thesis focuses on the methods and high order methods used to produce such results. In particular, we focus on incremental methods to scale the processing of repositories, declarative methods to compose a heterogeneous analysis, and high order methods used to reason about threats to methods operating on repositories. We summarize this as technical and methodological improvements. We contribute the improvements to methods and high-order methods in the context of MSR/ESE to produce future empirical results more effectively. We contribute the following improvements. We propose a method to improve the scalability of functions that abstract over repositories with high revision count in a theoretically founded way. We use insights on abstract algebra and program incrementalization to define a core interface of highorder functions that compute scalable static abstractions of a repository with many revisions. We evaluate the scalability of our method by benchmarks, comparing a prototype with available competitors in MSR/ESE. We propose a method to improve the definition of functions that abstract over a repository with a heterogeneous technology stack, by using concepts from declarative logic programming and combining them with ideas on megamodeling and linguistic architecture. We reproduce existing ideas on declarative logic programming with languages close to Datalog, coming from architecture recovery, source code querying, and static program analysis, and transfer them from the analysis of a homogeneous to a heterogeneous technology stack. We provide a prove-of-concept of such method in a case study. We propose a high-order method to improve the disambiguation of threats to methods used in MSR/ESE. We focus on a better disambiguation of threats, operationalizing reasoning about them, and making the implications to a valid data analysis methodology explicit, by using simulations. We encourage researchers to accomplish their work by implementing ‘fake’ simulations of their MSR/ESE scenarios, to operationalize relevant insights about alternative plausible results, negative results, potential threats and the used data analysis methodologies. We prove that such way of simulation based testing contributes to the disambiguation of threats in published MSR/ESE research.
This thesis addresses the problem of terrain classification in unstructured outdoor environments. Terrain classification includes the detection of obstacles and passable areas as well as the analysis of ground surfaces. A 3D laser range finder is used as primary sensor for perceiving the surroundings of the robot. First of all, a grid structure is introduced for data reduction. The chosen data representation allows for multi-sensor integration, e.g., cameras for color and texture information or further laser range finders for improved data density. Subsequently, features are computed for each terrain cell within the grid. Classification is performedrnwith a Markov random field for context-sensitivity and to compensate for sensor noise and varying data density within the grid. A Gibbs sampler is used for optimization and is parallelized on the CPU and GPU in order to achieve real-time performance. Dynamic obstacles are detected and tracked using different state-of-the-art approaches. The resulting information - where other traffic participants move and are going to move to - is used to perform inference in regions where the terrain surface is partially or completely invisible for the sensors. Algorithms are tested and validated on different autonomous robot platforms and the evaluation is carried out with human-annotated ground truth maps of millions of measurements. The terrain classification approach of this thesis proved reliable in all real-time scenarios and domains and yielded new insights. Furthermore, if combined with a path planning algorithm, it enables full autonomy for all kinds of wheeled outdoor robots in natural outdoor environments.