@misc{422, author = {{Sanati, Maryam}}, publisher = {{Universität Paderborn}}, title = {{{Formal Semantics of Probabilistic SMT Solving in Verification of Service Compositions}}}, year = {{2014}}, } @misc{423, author = {{Jojiju, Suman}}, publisher = {{Universität Paderborn}}, title = {{{Finding Optimal Self-Adaption Rules by Design-Space Exploration}}}, year = {{2014}}, } @misc{424, author = {{Finkensiep, Christoph}}, publisher = {{Universität Paderborn}}, title = {{{Fast and Flexible Automatic Composition of Semantic Web Services}}}, year = {{2014}}, } @inproceedings{425, abstract = {{In this paper, we evaluate the robustness of our color-based segmentation approach in combination with different color spaces, namely RGB, L*a*b*, HSV, and log-chromaticity (LCCS). For this purpose, we describe our deterministic segmentation algorithm including its gradually transformation of pixel-precise image data into a less error-prone and therefore more robust statistical representation in terms of moments. To investigate the robustness of a specific segmentation setting, we introduce our evaluation framework that directly works on the statistical representation. It is based on two different types of robustness measures, namely relative and absolute robustness. While relative robustness measures stability of segmentation results over time, absolute robustness measures stability regarding varying illumination by comparing results with ground truth data. The significance of these robustness measures is shown by evaluating our segmentation approach with different color spaces. For the evaluation process, an artificial scene was chosen as representative for application scenarios based on artificial landmarks.}}, author = {{Jungmann, Alexander and Jatzkowski, Jan and Kleinjohann, Bernd}}, booktitle = {{Proceedings of the 9th International Conference on Computer Vision Theory and Applications (VISAPP)}}, pages = {{648--655}}, title = {{{Evaluation of Color Spaces for Robust Image Segmentation}}}, year = {{2014}}, } @misc{427, author = {{Bulk, Benjamin}}, publisher = {{Universität Paderborn}}, title = {{{Evaluating the Influence of Different Abstraction Levels of Software Design on Performance prediction}}}, year = {{2014}}, } @inproceedings{428, abstract = {{Services are self-contained software components that can be used platform independent and that aim at maximizing software reuse. A basic concern in service oriented architectures is to measure the reusability of services. One of the most important qualities is the functional reusability, which indicates how relevant the task is that a service solves. Current metrics for functional reusability of software, however, either require source code analysis or have very little explanatory power. This paper gives a formally described vision statement for the estimation of functional reusability of services and sketches an exemplary reusability metric that is based on the service descriptions.}}, author = {{Mohr, Felix}}, booktitle = {{Proceedings of the 12th International Conference on Service Oriented Computing (ICSOC)}}, pages = {{411--418}}, title = {{{Estimating Functional Reusability of Services}}}, year = {{2014}}, } @misc{430, author = {{Krakau, Andreas}}, publisher = {{Universität Paderborn}}, title = {{{Entwicklung eines Konzepts zur Kodierung eines objektorientierten Typsystems in SMT}}}, year = {{2014}}, } @inproceedings{433, abstract = {{Virtual FPGAs are overlay architectures realized on top of physical FPGAs. They are proposed to enhance or abstract away from the physical FPGA for experimenting with novel architectures and design tool flows. In this paper, we present an embedding of a ZUMA-based virtual FPGA fabric into a complete configurable system-on-chip. Such an embedding is required to fully harness the potential of virtual FPGAs, in particular to give the virtual circuits access to main memory and operating system services, and to enable a concurrent operation of virtualized and non-virtualized circuitry. We discuss our extension to ZUMA and its embedding into the ReconOS operating system for hardware/software systems. Furthermore, we present an open source tool flow to synthesize configurations for the virtual FPGA.}}, author = {{Wiersema, Tobias and Bockhorn, Arne and Platzner, Marco}}, booktitle = {{Proceedings of the International Conference on ReConFigurable Computing and FPGAs (ReConFig)}}, pages = {{1--6 }}, title = {{{Embedding FPGA Overlays into Configurable Systems-on-Chip: ReconOS meets ZUMA}}}, doi = {{10.1109/ReConFig.2014.7032514}}, year = {{2014}}, } @inproceedings{5189, author = {{Arzt, Steven and Rasthofer, Siegfried and Fritz, Christian and Bodden, Eric and Bartel, Alexandre and Klein, Jacques and Le Traon, Yves and Octeau, Damien and McDaniel, Patrick}}, booktitle = {{Proceedings of the 35th ACM SIGPLAN Conference on Programming Language Design and Implementation - PLDI '14}}, isbn = {{9781450327848}}, publisher = {{ACM Press}}, title = {{{FlowDroid: Precise Context, Flow, Field, Object-sensitive and Lifecycle-aware Taint Analysis for Android Apps}}}, doi = {{10.1145/2594291.2594299}}, year = {{2014}}, } @inproceedings{5190, author = {{Arzt, Steven and Rasthofer, Siegfried and Lovat, Enrico and Bodden, Eric}}, booktitle = {{International Conference on Availability, Reliability and Security (ARES 2014)}}, pages = {{40--49}}, publisher = {{IEEE}}, title = {{{DroidForce: Enforcing Complex, Data-Centric, System-Wide Policies in Android}}}, year = {{2014}}, } @inproceedings{469, abstract = {{Runtime monitoring aims at ensuring program safety by monitoring the program's behaviour during execution and taking appropriate action before a program violates some property.Runtime monitoring is in particular important when an exhaustive formal verification fails. While the approach allows for a safe execution of programs, it may impose a significant runtime overhead.In this paper, we propose a novel technique combining verification and monitoring which incurs no overhead during runtime at all. The technique proceeds by using the inconclusive result of a verification run as the basis for transforming the program into one where all potential points of failure are replaced by HALT statements. The new program is safe by construction, behaviourally equivalent to the original program (except for unsafe behaviour),and has the same performance characteristics.}}, author = {{Wonisch, Daniel and Schremmer, Alexander and Wehrheim, Heike}}, booktitle = {{Proceedings of the 11th International Conference on Software Engineering and Formal Methods (SEFM)}}, pages = {{244--258}}, title = {{{Zero Overhead Runtime Monitoring}}}, doi = {{10.1007/978-3-642-40561-7_17}}, year = {{2013}}, } @misc{472, author = {{Engelbrecht, Marco}}, publisher = {{Universität Paderborn}}, title = {{{Vergleichsstudie zur Ausdrucksstärke von SMT-Solvern}}}, year = {{2013}}, } @phdthesis{478, abstract = {{Software systems are playing an increasing role in our everyday life, and as the amount of software applications grows, so does their complexity and the relevance of their computations. Software components can be found in many systems that are charged with safety-critical tasks, such as control systems for aviation or power plants. Hence, software verification techniques that are capable of proving the absence of critical errors are becoming more and more important in the field software engineering. A well-established approach to software verification is model checking. Applying this technique involves an exhaustive exploration of a state space model corresponding to the system under consideration. The major challenge in model checking is the so-called state explosion problem: The state space of a software system grows exponentially with its size. Thus, the straightforward modelling of real-life systems practically impossible. A common approach to this problem is the application of abstraction techniques, which reduce the original state space by mapping it on a significantly smaller abstract one. Abstraction inherently involves a loss of information, and thus, the resulting abstract model may be too imprecise for a definite result in verification. Therefore, abstraction is typically combined with abstraction refinement: An initially very coarse abstract model is iteratively refined, i.e. enriched with new details about the original system, until a level of abstraction is reached that is precise enough for a definite outcome. Abstraction refinement-based model checking is fully automatable and it is considered as one of the most promising approaches to the state explosion problem in verification. However, it is still faced with a number of challenges. There exist several types of abstraction techniques and not every type is equally well-suited for all kinds of systems and verification tasks. Moreover, the selection of adequate refinement steps is nontrivial and typically the most crucial part of the overall approach: Unfavourable refinement decisions can compromise the state space-reducing effect of abstraction, and as a consequence, can easily lead to the failure of verification. It is, however, hard to predict which refinement steps will eventually be expedient for verification – and which not.}}, author = {{Timm, Nils}}, publisher = {{Universität Paderborn}}, title = {{{Three-Valued Abstraction and Heuristic-Guided Refinement for Verifying Concurrent Systems}}}, year = {{2013}}, } @misc{482, author = {{Bieshaar, Maarten}}, publisher = {{Universität Paderborn}}, title = {{{Statistisches Planen von Aktionen für autonome mobile Roboter in realen Umgebungen}}}, year = {{2013}}, } @inproceedings{483, abstract = {{Modern software systems adapt themselves to changing environments, to meet quality-of-service requirements, such as response time limits. The engineering of the system’s self-adaptation logic does not only require new modeling methods, but also new analyzes of transient phases. Model-driven software performance engineering methods already allow design-time analysis of steady states of non-adaptive system models. In order to validate requirements for transient phases, new modeling and analysis methods are needed. In this paper, we present SimuLizar, our initial model-driven approach to model self-adaptive systems and analyze the performance of their transient phases. Our evaluation of a load balancer toy example shows the applicability of our modeling approach. Additionally, a comparison of our performance analysis with a prototypical implementation of our example system shows that the prediction accuracy is sufficient to identify unsatisfactory self-adaptations.}}, author = {{Becker, Matthias and Becker, Steffen and Meyer, Joachim}}, booktitle = {{Proceedings of the Software Engineering Conference (SE)}}, pages = {{71--84}}, title = {{{SimuLizar: Design-Time modeling and Performance Analysis of Self-Adaptive Systems}}}, year = {{2013}}, } @inproceedings{484, abstract = {{One of the main ideas of Service-Oriented Computing (SOC) is the delivery of flexibly composable services provided on world-wide markets. For a successful service discovery,service requests have to be matched with the available service offers. However, in a situation in which no service that completely matches the request can be discovered, the customer may tolerate slight discrepancies between request and offer. Some existing fuzzy matching approaches are able to detectsuch service variants, but they do not allow to explicitly specify which parts of a request are not mandatory. In this paper, we improve an existing service matching approach based onVisual Contracts leveraging our preliminary work of design pattern detection. Thereby, we support explicit specifications of service variants and realize gradual matching results that can be ranked in order to discover the service offer that matches a customer’s request best.}}, author = {{Platenius, Marie Christin and von Detten, Markus and Gerth, Christian and Schäfer, Wilhelm and Engels, Gregor}}, booktitle = {{IEEE 20th International Conference on Web Services (ICWS 2013)}}, pages = {{613--614}}, title = {{{Service Matching under Consideration of Explicitly Specified Service Variants}}}, doi = {{10.1109/ICWS.2013.98}}, year = {{2013}}, } @inproceedings{485, abstract = {{Software composition has been studied as a subject of state based planning for decades. Existing composition approaches that are efficient enough to be used in practice are limited to sequential arrangements of software components. This restriction dramatically reduces the number of composition problems that can be solved. However, there are many composition problems that could be solved by existing approaches if they had a possibility to combine components in very simple non-sequential ways. To this end, we present an approach that arranges not only basic components but also composite components. Composite components enhance the structure of the composition by conditional control flows. Through algorithms that are written by experts, composite components are automatically generated before the composition process starts. Therefore, our approach is not a substitute for existing composition algorithms but complements them with a preprocessing step. We verified the validity of our approach through implementation of the presented algorithms.}}, author = {{Mohr, Felix and Kleine Büning, Hans}}, booktitle = {{Proceedings of the 15th International Conference on Information Integration and Web-based Applications & Services (iiWAS)}}, pages = {{676--680}}, title = {{{Semi-Automated Software Composition Through Generated Components}}}, doi = {{10.1145/2539150.2539235}}, year = {{2013}}, } @phdthesis{494, abstract = {{The maintenance of component-based software systems requires up-to-date models of their concrete architecture, i.e. the architecture that is realised in the source code. These models help in systematically planning, analysing and executing typical reengineering activities. Often no or only outdated architectural models of such systems exist. Therefore, various reverse engineering methods have been developed which try to recover a system's components, subsystems and connectors. However, these reverse engineering methods are severely impacted by design deciencies in the system's code base, especially violations of the component encapsulation. As long as design deciencies are not considered in the reverse engineering process, they reduce the quality of the recovered component structures. Despite this impact of design deciencies, no existing architecture reconstruction approach explicitly integrates a systematic deciency detection and removal into the recovery process. Therefore, I have developed Archimetrix. Archimetrix is a tool-supported architecture reconstruction process. It enhances a clustering-based architecture recovery approach with an extensible, pattern-based deciency detection. After the detection of deciencies, Archimetrix supports the software architect in removing the de ciencies and provides the means to preview the architectural consequences of such a removal. I also provide a process to identify and formalise additional deciencies. I validated the approach on three case studies which show that Archimetrix is able to identify relevant deciencies and that the removal of these deciencies leads to an increased quality of the recovered architectures, i.e. they are closer to the corresponding conceptual architectures.}}, author = {{von Detten, Markus}}, publisher = {{Universität Paderborn}}, title = {{{Reengineering of Component-Based Software Systems in the Presence of Design Deficiencies}}}, year = {{2013}}, } @inproceedings{495, abstract = {{Automated service composition has been studied as a subject of state based planning for a decade. A great deal of service composition tasks can only be solved if concrete output values of the services are considered in the composition process. However, the fact that those values are not known before runtime leads to nondeterministic planning problems, which have proven to be notoriously difficult in practical automated service composition applications. Even though this problem is frequently recognized, it has still received remarkably few attention and remains unsolved.This paper shows how nondeterminism in automated service composition can be reduced. We introduce context rules as a means to derive semantic knowledge from output values of services. These rules enable us to replace nondeterministic composition operations by less nondeterministic or even completely deterministic ones. We show the validity of our solutions not only theoretically but also have evaluated them practically through implementation.}}, author = {{Mohr, Felix and Lettmann, Theodor and Kleine Büning, Hans}}, booktitle = {{Proceedings of the 6th International Conference on Service Oriented Computing and Applications (SOCA)}}, pages = {{154--161}}, title = {{{Reducing Nondeterminism in Automated Service Composition}}}, doi = {{10.1109/SOCA.2013.25}}, year = {{2013}}, } @inproceedings{498, abstract = {{Proof-carrying code approaches aim at safe execution of untrusted code by having the code producer attach a safety proof to the code which the code consumer only has to validate. Depending on the type of safety property, proofs can however become quite large and their validation - though faster than their construction - still time consuming. In this paper we introduce a new concept for safe execution of untrusted code. It keeps the idea of putting the time consuming part of proving on the side of the code producer, however, attaches no proofs to code anymore but instead uses the proof to transform the program into an equivalent but more efficiently verifiable program. Code consumers thus still do proving themselves, however, on a computationally inexpensive level only. Experimental results show that the proof effort can be reduced by several orders of magnitude, both with respect to time and space.}}, author = {{Wonisch, Daniel and Schremmer, Alexander and Wehrheim, Heike}}, booktitle = {{Proceedings of the 25th International Conference on Computer Aided Verification (CAV)}}, pages = {{912--927}}, title = {{{Programs from Proofs – A PCC Alternative}}}, doi = {{10.1007/978-3-642-39799-8_65}}, year = {{2013}}, }