@inproceedings{319, abstract = {{Services are self-contained and platform independent software components that aim at maximizing software reuse. The automated composition of services to a target software artifact has been tackled with many AI techniques, but existing approaches make unreasonably strong assumptions such as a predefined data flow, are limited to tiny problem sizes, ignore non-functional properties, or assume offline service repositories. This paper presents an algorithm that automatically composes services without making such assumptions. We employ a backward search algorithm that starts from an empty composition and prepends service calls to already discovered candidates until a solution is found. Available services are determined during the search process. We implemented our algorithm, performed an experimental evaluation, and compared it to other approaches.}}, author = {{Mohr, Felix and Jungmann, Alexander and Kleine Büning, Hans}}, booktitle = {{Proceedings of the 12th IEEE International Conference on Services Computing (SCC)}}, pages = {{57----64}}, title = {{{Automated Online Service Composition}}}, doi = {{10.1109/SCC.2015.18}}, year = {{2015}}, } @phdthesis{270, author = {{Abshoff, Sebastian}}, publisher = {{Universität Paderborn}}, title = {{{On the Complexity of Fundamental Problems in Dynamic Ad-hoc Networks}}}, year = {{2015}}, } @inproceedings{271, abstract = {{In \emph{bandwidth allocation games} (BAGs), the strategy of a player consists of various demands on different resources. The player's utility is at most the sum of these demands, provided they are fully satisfied. Every resource has a limited capacity and if it is exceeded by the total demand, it has to be split between the players. Since these games generally do not have pure Nash equilibria, we consider approximate pure Nash equilibria, in which no player can improve her utility by more than some fixed factor $\alpha$ through unilateral strategy changes. There is a threshold $\alpha_\delta$ (where $\delta$ is a parameter that limits the demand of each player on a specific resource) such that $\alpha$-approximate pure Nash equilibria always exist for $\alpha \geq \alpha_\delta$, but not for $\alpha < \alpha_\delta$. We give both upper and lower bounds on this threshold $\alpha_\delta$ and show that the corresponding decision problem is ${\sf NP}$-hard. We also show that the $\alpha$-approximate price of anarchy for BAGs is $\alpha+1$. For a restricted version of the game, where demands of players only differ slightly from each other (e.g. symmetric games), we show that approximate Nash equilibria can be reached (and thus also be computed) in polynomial time using the best-response dynamic. Finally, we show that a broader class of utility-maximization games (which includes BAGs) converges quickly towards states whose social welfare is close to the optimum.}}, author = {{Drees, Maximilian and Feldotto, Matthias and Riechers, Sören and Skopalik, Alexander}}, booktitle = {{Proceedings of the 8th International Symposium on Algorithmic Game Theory (SAGT)}}, pages = {{178--189}}, title = {{{On Existence and Properties of Approximate Pure Nash Equilibria in Bandwidth Allocation Games}}}, doi = {{10.1007/978-3-662-48433-3_14}}, year = {{2015}}, } @inproceedings{27163, author = {{Keil, Reinhard and Selke, Harald}}, editor = {{Keil, Reinhard and Selke, Harald}}, pages = {{39--53}}, publisher = {{publishing series of the Heinz Nixdorf Institute, Paderborn}}, title = {{{Virtual knowledge {\ "a} ume - From the presentation of content to virtual learning {\" a} tten}}}, volume = {{330}}, year = {{2015}}, } @phdthesis{27164, author = {{Klompmaker, Florian}}, publisher = {{Universitaetsbibliothek Paderborn}}, title = {{{Development of a structured process of interaction design for {\ "u} r nat {\" u} local user interfaces}}}, year = {{2015}}, } @inproceedings{27165, abstract = {{Patterns serve to codify design knowledge. By embedding them in a hypothesis-driven design, it is possible to develop them further into sample languages. For this it is necessary to resolve the underlying conflicts in the form of design hypotheses and to validate them empirically in order to enable further use and generalization. In this article, an experiment is presented that describes this procedure and demonstrates the interplay between theory formation and codification of design knowledge using two examples.}}, author = {{Schild, Christian and Petrausch, Vanessa}}, pages = {{173--182}}, publisher = {{De Gruyter Oldenbourg}}, title = {{{Empirical validation of design patterns }}}, year = {{2015}}, } @misc{273, author = {{Kohn, Kathlén}}, publisher = {{Universität Paderborn}}, title = {{{Number of Voronoi-relevant vectors in lattices with respect to arbitrary norms}}}, year = {{2015}}, } @inproceedings{274, abstract = {{Consider the problem in which n jobs that are classified into k types are to be scheduled on m identical machines without preemption. A machine requires a proper setup taking s time units before processing jobs of a given type. The objective is to minimize the makespan of the resulting schedule. We design and analyze an approximation algorithm that runs in time polynomial in n,m and k and computes a solution with an approximation factor that can be made arbitrarily close to 3/2.}}, author = {{Mäcker, Alexander and Malatyali, Manuel and Meyer auf der Heide, Friedhelm and Riechers, Sören}}, booktitle = {{Algorithms and Data Structures: 14th International Symposium, WADS 2015, Victoria, BC, Canada, August 5-7, 2015. Proceedings}}, editor = {{Dehne, Frank and Sack, Jörg Rüdiger and Stege, Ulrike}}, pages = {{542----553}}, title = {{{Non-preemptive Scheduling on Machines with Setup Times}}}, doi = {{10.1007/978-3-319-21840-3_45}}, year = {{2015}}, } @inproceedings{275, abstract = {{We investigate a non-cooperative game-theoretic model for the formation of communication networks by selfish agents. Each agent aims for a central position at minimum cost for creating edges. In particular, the general model (Fabrikant et al., PODC'03) became popular for studying the structure of the Internet or social networks. Despite its significance, locality in this game was first studied only recently (Bilò et al., SPAA'14), where a worst case locality model was presented, which came with a high efficiency loss in terms of quality of equilibria. Our main contribution is a new and more optimistic view on locality: agents are limited in their knowledge and actions to their local view ranges, but can probe different strategies and finally choose the best. We study the influence of our locality notion on the hardness of computing best responses, convergence to equilibria, and quality of equilibria. Moreover, we compare the strength of local versus non-local strategy changes. Our results address the gap between the original model and the worst case locality variant. On the bright side, our efficiency results are in line with observations from the original model, yet we have a non-constant lower bound on the Price of Anarchy.}}, author = {{Cord-Landwehr, Andreas and Lenzner, Pascal}}, booktitle = {{Proceedings of the 40th Conference on Mathematical Foundations of Computer Science (MFCS)}}, pages = {{248----260}}, title = {{{Network Creation Games: Think Global - Act Local}}}, doi = {{10.1007/978-3-662-48054-0_21}}, year = {{2015}}, } @misc{277, author = {{Kothe, Nils}}, publisher = {{Universität Paderborn}}, title = {{{Multilevel Netzwerk Spiele mit konstanten Entfernungen im Highspeed-Netzwerk}}}, year = {{2015}}, } @misc{278, author = {{Feldmann, Michael}}, publisher = {{Universität Paderborn}}, title = {{{Monotonic Searchability for distributed sorted Lists and De Bruijn Graphs}}}, year = {{2015}}, } @inproceedings{279, abstract = {{Service discovery in global software markets is performed by brokers who act as intermediaries between service consumers and service providers.In order to discover services, brokers apply service matching for determining whether the specification of a provided service satisfies the consumer's requirements.Brokers can already choose between a lot of different service matching approaches considering different service properties (structural, behavioral, and non-functional properties).Different matching approaches can be combined into configurable matching processes leading to a high matching quality (e.g., accurate matching results). However, this combination and configuration is a manual procedure and has to be repeated for different consumers' or market requirements regarding matching quality. In this paper, we propose our framework MatchBox, which supports a broker in reusing existing matching approaches and combining them in a model-driven way based on a reconfigurable model of the matching process.Using this reconfigurable model, MatchBox takes care of control and data flow between matching approaches and executes the modeled processes automatically.As a case study, we integrated eleven matchers into MatchBox to demonstrate that it remains flexibility and reduces effort for a broker at the same time.}}, author = {{Platenius, Marie Christin and Arifulina, Svetlana and Schäfer, Wilhelm}}, booktitle = {{Proceedings of the 18th International ACM Sigsoft Symposium on Component-Based Software Engineering (CBSE'15)}}, pages = {{75--84}}, title = {{{MatchBox: A Framework for Dynamic Configuration of Service Matching Processes}}}, doi = {{10.1145/2737166.2737174}}, year = {{2015}}, } @techreport{20977, author = {{Schäfer, Wilhelm and Dziwok, Stefan and Pohlmann, Uwe and Bobolz, Jan and Czech, Mike and Dann, Andreas Peter and Geismann, Johannes and Hüwe, Marcus and Krieger, Arthur and Piskachev, Goran and Schubert, David and Wohlrab, Rebekka}}, title = {{{Seminar Theses of the Project Group Cybertron}}}, year = {{2015}}, } @inproceedings{20979, author = {{Stockmann, Lars}}, booktitle = {{Proceedings of the Doctoral Symposium of the ACM/IEEE 18th International Conference on Model Driven Engineering Languages and Systems}}, editor = {{Chechik, Marsha and Kolovos, Dimitris}}, title = {{{Debugging Models in the Context of Automotive Software Development}}}, year = {{2015}}, } @inproceedings{17425, author = {{Berssenbrügge, Jan and Wiederkehr, Olga and Jähn, Claudius and Fischer, Matthias}}, booktitle = {{12. Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung}}, pages = {{65--78}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts}}, title = {{{Anbindung des Virtuellen Prototypen an die Partialmodelle intelligenter technischer Systeme}}}, volume = {{343}}, year = {{2015}}, } @inproceedings{17427, author = {{Jähn, Claudius and Fischer, Matthias and Gerges, Maria and Berssenbrügge, Jan}}, booktitle = {{12. Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung}}, pages = {{107--120}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts}}, title = {{{Automatische Ableitung geometrischer Eigenschaften von Bauteilen aus dem 3-D-Polygonmodell}}}, volume = {{342}}, year = {{2015}}, } @book{17431, editor = {{Gausemeier, Jürgen and Grafe, Michael and Meyer auf der Heide, Friedhelm}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts}}, title = {{{Augmented & Virtual Reality in der Produktentstehung: Grundlagen, Methoden und Werkzeuge; Interaktions- und Visualisierungstechniken, Virtual Prototyping intelligenter technischer Systeme mit AR/VR}}}, volume = {{342}}, year = {{2015}}, } @article{17657, abstract = {{Inter-datacenter transfers of non-interactive but timely large flows over a private (managed) network is an important problem faced by many cloud service providers. The considered flows are non-interactive because they do not explicitly target the end users. However, most of them must be performed on a timely basis and are associated with a deadline. We propose to schedule these flows by a centralized controller, which determines when to transmit each flow and which path to use. Two scheduling models are presented in this paper. In the first, the controller also determines the rate of each flow, while in the second bandwidth is assigned by the network according to the TCP rules. We develop scheduling algorithms for both models and compare their complexity and performance.}}, author = {{Cohen, R. and Polevoy, Gleb}}, issn = {{2168-7161}}, journal = {{Cloud Computing, IEEE Transactions on}}, keywords = {{Approximation algorithms, Approximation methods, Bandwidth, Cloud computing, Routing, Schedules, Scheduling}}, number = {{99}}, pages = {{1--1}}, title = {{{Inter-Datacenter Scheduling of Large Data Flows}}}, doi = {{10.1109/TCC.2015.2487964}}, volume = {{PP}}, year = {{2015}}, } @article{17658, abstract = {{Abstract We study the problem of bandwidth allocation with multiple interferences. In this problem the input consists of a set of users and a set of base stations. Each user has a list of requests, each consisting of a base station, a frequency demand, and a profit that may be gained by scheduling this request. The goal is to find a maximum profit set of user requests S that satisfies the following conditions: (i) S contains at most one request per user, (ii) the frequency sets allotted to requests in S that correspond to the same base station are pairwise non-intersecting, and (iii) the QoS received by any user at any frequency is reasonable according to an interference model. In this paper we consider two variants of bandwidth allocation with multiple interferences. In the first each request specifies a demand that can be satisfied by any subset of frequencies that is large enough. In the second each request specifies a specific frequency interval. Furthermore, we consider two interference models, multiplicative and additive. We show that these problems are extremely hard to approximate if the interferences depend on both the interfered and the interfering base stations. On the other hand, we provide constant factor approximation algorithms for both variants of bandwidth allocation with multiple interferences for the case where the interferences depend only on the interfering base stations. We also consider a restrictive special case that is closely related to the Knapsack problem. We show that this special case is NP-hard and that it admits an FPTAS. }}, author = {{Bar-Yehuda, Reuven and Polevoy, Gleb and Rawitz, Dror}}, issn = {{0166-218X}}, journal = {{Discrete Applied Mathematics }}, keywords = {{Local ratio}}, pages = {{23 -- 36}}, publisher = {{Elsevier}}, title = {{{Bandwidth allocation in cellular networks with multiple interferences}}}, doi = {{http://dx.doi.org/10.1016/j.dam.2015.05.013}}, volume = {{194}}, year = {{2015}}, } @article{1769, abstract = {{Große zylindrische Stahlprüflinge werden mittels der Methode der finiten Differenzen im Zeitbereich (engl. finite differences in time domain, FDTD) simulativ untersucht. Dabei werden Pitch-Catch-Messanordnungen verwendet. Es werden zwei Bildgebungsansätze vorgestellt: ersterer basiert auf dem Imaging Principle nach Claerbout, letzterer basiert auf gradientenbasierter Optimierung eines Zielfunktionals.}}, author = {{Hegler, Sebastian and Statz, Christoph and Mütze, Marco and Mooshofer, Hubert and Goldammer, Matthias and Fendt, Karl and Schwarzer, Stefan and Feldhoff, Kim and Flehmig, Martin and Markwardt, Ulf and E. Nagel, Wolfgang and Schütte, Maria and Walther, Andrea and Meinel, Michael and Basermann, Achim and Plettemeier, Dirk}}, journal = {{tm - Technisches Messen}}, number = {{9}}, pages = {{440--450}}, publisher = {{Walter de Gruyter}}, title = {{{Simulative Ultraschall-Untersuchung von Pitch-Catch-Messanordnungen für große zylindrische Stahl-Prüflinge und gradientenbasierte Bildgebung}}}, doi = {{doi:10.1515/teme-2015-0031}}, volume = {{82}}, year = {{2015}}, }