@inproceedings{1891, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{2011 International Conference on Distributed Computing Systems, ICDCS 2011, Minneapolis, Minnesota, USA, June 20-24, 2011}}, isbn = {{978-0-7695-4364-2}}, pages = {{507----516}}, publisher = {{IEEE Computer Society}}, title = {{{Competitive and Fair Medium Access Despite Reactive Jamming}}}, doi = {{10.1109/ICDCS.2011.8}}, year = {{2011}}, } @inproceedings{1892, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{Proceedings of the 3rd ACM workshop on Wireless of the students, by the students, for the students, S3@MOBICOM 2011, Las Vegas, NV, USA, September 19 - 23, 2011}}, isbn = {{978-1-4503-0868-7}}, pages = {{33----36}}, publisher = {{ACM}}, title = {{{Towards jamming-resistant and competitive medium access in the SINR model}}}, doi = {{10.1145/2030686.2030697}}, year = {{2011}}, } @inproceedings{1893, author = {{W. Richa, Andrea and Scheideler, Christian and Schmid, Stefan and Zhang, Jin}}, booktitle = {{Proceedings of the 12th ACM Interational Symposium on Mobile Ad Hoc Networking and Computing, MobiHoc 2011, Paris, France, May 16-20, 2011}}, isbn = {{978-1-4503-0722-2}}, pages = {{15}}, publisher = {{ACM}}, title = {{{Self-stabilizing leader election for single-hop wireless networks despite jamming}}}, doi = {{10.1145/2107502.2107522}}, year = {{2011}}, } @inproceedings{1895, author = {{Kniesburges, Sebastian and Koutsopoulos, Andreas and Scheideler, Christian}}, booktitle = {{SPAA 2011: Proceedings of the 23rd Annual ACM Symposium on Parallelism in Algorithms and Architectures, San Jose, CA, USA, June 4-6, 2011 (Co-located with FCRC 2011)}}, isbn = {{978-1-4503-0743-7}}, pages = {{235----244}}, title = {{{Re-Chord: a self-stabilizing chord overlay network}}}, doi = {{10.1145/1989493.1989527}}, year = {{2011}}, } @phdthesis{18973, author = {{Frahling, Gereon}}, isbn = {{978-3-942647-09-0}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{Algorithms for Dynamic Geometric Data Streams}}}, volume = {{290}}, year = {{2011}}, } @phdthesis{18974, author = {{Mehler, Jan}}, isbn = {{978-3-942647-06-9}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{Power-Aware Online File Allocation in Dynamic Networks}}}, volume = {{287}}, year = {{2011}}, } @phdthesis{18976, abstract = {{Web computing is a variant of parallel computing where the idle times of PCs donated by worldwide distributed users are employed to execute parallel programs. In this thesis we consider a web computing variant with two important properties: First, we support the execution of coupled, massively parallel algorithms (rather than distributed data processing). And second, we organize the system in peer-to-peer fashion. We present the Paderborn University BSP-based Web Computing (PUB-Web) library, which supports the execution of parallel programs in the bulk-synchronous style (BSP) in such a web computing setting. In this thesis, we focus on important technical and algorithmic aspects, in particular: In order to schedule processes with respect to the currently available computing power, which continually changes in an unpredictable fashion, we need intelligent load balancing algorithms and -- as a basic precondition -- the technical ability to migrate threads at runtime. To achieve the latter in a way suitable for production use, compatible with recent Java versions, available for all important platforms, and easy-to-use for developers, we develop the PadMig thread migration and checkpointing library. In order to tackle the distributed load balancing problem, we present an algorithm based on Distributed Heterogeneous Hash-Tables. In order to judge the quality of the schedules produced, we perform extensive experiments to compare several variants of the DHHT-based load balancer with the well- established Work Stealing algorithm, using realistic input data obtained by profiling the utilization of several hundred PCs for a period of several months. Beside the available computing power, we finally also consider the network bandwidth as a secondary criterion for load balancing. For this purpose, we cluster the PUB-Web network according to bandwidth, employing a novel, fault-tolerant, adaptive, and scaling distributed clustering algorithm called DiDiC. In order to judge the quality of the clusterings produces by DiDiC, we experimentally compare it to the well-established MCL algorithm using a simulator.}}, author = {{Gehweiler, Joachim}}, isbn = {{978-3-942647-17-5}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{Peer-to-Peer Based Parallel Web Computing}}}, volume = {{298}}, year = {{2011}}, } @inproceedings{1899, author = {{Kniesburges, Sebastian and Scheideler, Christian}}, booktitle = {{WALCOM: Algorithms and Computation - 5th International Workshop, WALCOM 2011, New Delhi, India, February 18-20, 2011. Proceedings}}, isbn = {{978-3-642-19093-3}}, pages = {{170----181}}, publisher = {{Springer}}, title = {{{Hashed Patricia Trie: Efficient Longest Prefix Matching in Peer-to-Peer Systems}}}, doi = {{10.1007/978-3-642-19094-0_18}}, volume = {{6552}}, year = {{2011}}, } @inbook{1900, author = {{Scheideler, Christian and Graffi, Kalman}}, booktitle = {{Computer Science, The Hardware, Software and Heart of It}}, isbn = {{978-1-4614-1167-3}}, pages = {{155----168}}, publisher = {{Springer}}, title = {{{Programming for Distributed Computing: From Physical to Logical Networks}}}, doi = {{10.1007/978-1-4614-1168-0_9}}, year = {{2011}}, } @inbook{1901, author = {{Scheideler, Christian}}, booktitle = {{Algorithms Unplugged}}, isbn = {{978-3-642-15327-3}}, pages = {{223----229}}, publisher = {{Springer}}, title = {{{Broadcasting - How Can I Quickly Disseminate Information?}}}, doi = {{10.1007/978-3-642-15328-0_22}}, year = {{2011}}, } @book{1902, author = {{Vöcking, Berthold and Alt, Helmut and Dietzfelbinger, Martin and Reischuk, Rüdiger and Scheideler, Christian and Vollmer, Heribert and Wagner, Dorothea}}, isbn = {{978-3-642-15327-3}}, title = {{{Algorithms Unplugged}}}, doi = {{10.1007/978-3-642-15328-0}}, year = {{2011}}, } @inproceedings{19026, author = {{Briest, Patrick and Raupach, Christoph}}, booktitle = {{Proceedings of the 23rd ACM symposium on Parallelism in algorithms and architectures - SPAA '11}}, isbn = {{9781450307437}}, title = {{{The car sharing problem}}}, doi = {{10.1145/1989493.1989518}}, year = {{2011}}, } @phdthesis{19040, author = {{Effert, Sascha}}, title = {{{Verfahren zur redundanten Datenplatzierung in skalierbaren Speichersystemen}}}, year = {{2011}}, } @inproceedings{1924, author = {{Kolman, Petr and Scheideler, Christian}}, booktitle = {{28th International Symposium on Theoretical Aspects of Computer Science, STACS 2011, March 10-12, 2011, Dortmund, Germany}}, pages = {{129----140}}, title = {{{Towards Duality of Multicommodity Multiroute Cuts and Flows: Multilevel Ball-Growing}}}, doi = {{10.4230/LIPIcs.STACS.2011.129}}, year = {{2011}}, } @article{23739, abstract = {{This paper deals with the design of efficiently computable incentive-compatible mechanisms for combinatorial optimization problems with single-minded agents each possibly having multiple private parameters. We focus on approximation algorithms for NP-hard mechanism design problems. These algorithms need to satisfy certain monotonicity properties to ensure truthfulness. Since most of the known approximation techniques do not fulfill these properties, we study alternative techniques. Our first contribution is a quite general method to transform a pseudopolynomial algorithm into a monotone fully polynomial time approximation scheme (FPTAS). This can be applied to various problems like, e.g., knapsack, constrained shortest path, or job scheduling with deadlines. For example, the monotone FPTAS for the knapsack problem gives a very efficient, truthful mechanism for single-minded multiunit auctions. The best previous result for such auctions was a 2-appro-xi-ma-tion. In addition, we present a monotone PTAS for the generalized assignment problem with any constant number of private parameters per agent. The most efficient way to solve packing integer programs (PIPs) is linear programming–based randomized rounding, which also is in general not monotone. We show that primal-dual greedy algorithms achieve almost the same approximation ratios for PIPs as randomized rounding. The advantage is that these algorithms are inherently monotone. This way, we can significantly improve the approximation ratios of truthful mechanisms for various fundamental mechanism design problems like single-minded combinatorial auctions (CAs), unsplittable flow routing, and multicast routing. Our primal-dual approximation algorithms can also be used for the winner determination in CAs with general bidders specifying their bids through an oracle. }}, author = {{Briest, Patrick and Krysta, Piotr and Vöcking, Berthold}}, issn = {{0097-5397}}, journal = {{SIAM Journal on Computing}}, pages = {{1587--1622}}, title = {{{Approximation Techniques for Utilitarian Mechanism Design}}}, doi = {{10.1137/090772988}}, year = {{2011}}, } @article{23740, abstract = {{We investigate nonparametric multiproduct pricing problems, in which we want to find revenue maximizing prices for products $\mathcal{P}$ based on a set of customer samples $\mathcal{C}$. We mostly focus on the unit-demand case, in which products constitute strict substitutes and each customer aims to purchase a single product. In this setting a customer sample consists of a number of nonzero values for different products and possibly an additional product ranking. Once prices are fixed, each customer chooses to buy one of the products she can afford based on some predefined selection rule. We distinguish between the min-buying, max-buying, and rank-buying models. Some of our results also extend to single-minded pricing, in which case products are strict complements and every customer seeks to buy a single set of products, which she purchases if the sum of prices is below her valuation for that set. For the min-buying model we show that the revenue maximization problem is not approximable within factor $\mathcal{O}(\log^{\varepsilon}|\mathcal{C}|)$ for some constant $\varepsilon>0$, unless $\mathrm{NP}\subseteq\mathrm{DTIME}(n^{\mathcal{O}(\log\log n)})$, thereby almost closing the gap between the known algorithmic results and previous lower bounds. We also prove inapproximability within $\mathcal{O}(\ell^{\varepsilon})$, $\ell$ being an upper bound on the number of nonzero values per customer, and $\mathcal{O}(|\mathcal{P}|^{\varepsilon})$ under slightly stronger assumptions and provide matching upper bounds. Surprisingly, these hardness results hold even if a price ladder constraint, i.e., a predefined order on the prices of all products, is given. Without the price ladder constraint we obtain similar hardness results for the special case of uniform valuations, i.e., the case that every customer has identical values for all the products she is interested in, assuming specific hardness of the balanced bipartite independent set problem in constant degree graphs or hardness of refuting random 3CNF formulas. Introducing a slightly more general problem definition in which customers are given as an explicit probability distribution, we obtain inapproximability within $\mathcal{O}(|\mathcal{P}|^{\varepsilon})$ assuming $\mathrm{NP}\nsubseteq\bigcap_{\delta>0}\mathrm{BPTIME}(2^{\mathcal{O}(n^{\delta})})$. These results apply to single-minded pricing as well. For the max-buying model a polynomial-time approximation scheme exists if a price ladder is given. We give a matching lower bound by proving strong NP-hardness. Assuming limited product supply, we analyze a generic local search algorithm and prove that it is 2-approximate. Finally, we discuss implications for the rank-buying model. }}, author = {{Briest, Patrick and Krysta, Piotr}}, issn = {{0097-5397}}, journal = {{SIAM Journal on Computing}}, pages = {{1554--1586}}, title = {{{Buying Cheap Is Expensive: Approximability of Combinatorial Pricing Problems}}}, doi = {{10.1137/090752353}}, year = {{2011}}, } @inbook{20709, author = {{Cord-Landwehr, Andreas and Degener, Bastian and Fischer, Matthias and Hüllmann, Martina and Kempkes, Barbara and Klaas, Alexander and Kling, Peter and Kurras, Sven and Märtens, Marcus and auf der Heide, Friedhelm Meyer and Raupach, Christoph and Swierkot, Kamil and Warner, Daniel and Weddemann, Christoph and Wonisch, Daniel}}, booktitle = {{SOFSEM 2011: Theory and Practice of Computer Science}}, isbn = {{9783642183805}}, issn = {{0302-9743}}, title = {{{Collisionless Gathering of Robots with an Extent}}}, doi = {{10.1007/978-3-642-18381-2_15}}, year = {{2011}}, } @inbook{20710, author = {{Cord-Landwehr, Andreas and Degener, Bastian and Fischer, Matthias and Hüllmann, Martina and Kempkes, Barbara and Klaas, Alexander and Kling, Peter and Kurras, Sven and Märtens, Marcus and Meyer auf der Heide, Friedhelm and Raupach, Christoph and Swierkot, Kamil and Warner, Daniel and Weddemann, Christoph and Wonisch, Daniel}}, booktitle = {{Automata, Languages and Programming}}, isbn = {{9783642220111}}, issn = {{0302-9743}}, title = {{{A New Approach for Analyzing Convergence Algorithms for Mobile Robots}}}, doi = {{10.1007/978-3-642-22012-8_52}}, year = {{2011}}, } @inproceedings{20915, abstract = {{Durch die immer kuerzer werdenden Entwicklungszyklen und den groeßer werdenden Druck bzgl. Time-to-Market fuer eingebettete Systeme im Automobilsektor steigt der Bedarf, die Systeme bereits zu fruehen Entwicklungszeitpunkten gegenueber den Qualitaetsanforderungen (z. B. Zeitanforderungen und Ressourcenauslastung) zu verifizieren. Wir stellen einen Ansatz vor, der eine formale Spezifikation von Zeitanforderungen und Wirkketten sowie deren fruehzeitige Analyse durch Simulation erlaubt. Verletzungen von Zeitanforderungen werden in den Simulationsergebnissen automatisch erkannt. }}, author = {{Meyer, Jan and Holtmann, Jörg and Meyer, Matthias}}, booktitle = {{8. Paderborner Workshop Entwurf mechatronischer Systeme}}, pages = {{203--215}}, publisher = {{Heinz Nixdorf Institut}}, title = {{{Formalisierung von Anforderungen und Betriebssystemeigenschaften zur fruehzeitigen Simulation von eingebetteten, automobilen Systemen}}}, volume = {{294}}, year = {{2011}}, } @inproceedings{20916, abstract = {{Safety critical functions for embedded systems are increasingly realized with software. Current and future standards and maturity models impose high accuracy and quality for the development process of such software-intensive, embedded systems. But nowadays, there are process and tooling gaps between different modeling aspects for the system under development (SUD). Furthermore, the SUD is usually verified and validated not until it is completely implemented, which leads to expensive corrections. In this paper we present a seamless, model-based development process, which is intended for the automotive supplier domain and conforms to the process reference model of Automotive SPICE. The development process addresses the issues mentioned above by using systematic transitions between different modeling aspects and simulations in early development stages.}}, author = {{Holtmann, Jörg and Meyer, Jan and Meyer, Matthias}}, booktitle = {{Software Engineering 2011 – Workshopband (inkl. Doktorandensymposium)}}, pages = {{79--88}}, publisher = {{Bonner Koellen Verlag}}, title = {{{A Seamless Model-Based Development Process for Automotive Systems}}}, volume = {{P-184}}, year = {{2011}}, }