TY - CONF AB - Load balancing is an important requirement for the efficient execu-tion of parallel numerical simulations. In particular when the simulation domainchanges over time, the mapping of computational tasks to processors needs tobe modified accordingly. State-of-the-art libraries for this problem are basedon graph repartitioning. They have a number of drawbacks, including the opti-mized metric and the difficulty of parallelizing the popular repartitioning heuris-tic Kernighan-Lin (KL).Here we further explore the very promising diffusion-based graph partitioningalgorithm DIBAP (Meyerhenke et al., JPDC 69(9):750–761, 2009) by adaptingDIBAP to the related problem of load balancing. Experiments with graph se-quences that imitate adaptive numerical simulations demonstrate the applicabilityand high quality of DIBAP for load balancing by repartitioning. Compared to thefaster state-of-the-art repartitioners PARMETIS and parallel JOSTLE, DIBAP’ssolutions have partitions with significantly fewer external edges and boundarynodes and the resulting average migration volume in the important maximumnorm is also the best in most cases.We also prove that one of DIBAP’s key components optimizes a relaxed versionof the minimum edge cut problem. Moreover, we hint at a distributed algorithmbased on ideas used in DIBAP for clustering a virtual P2P supercomputer. AU - Gehweiler, Joachim AU - Meyerhenke, Henning ID - 19016 T2 - Dagstuhl Seminar Proceedings 10261: Algorithm Engineering TI - On Dynamic Graph Partitioning and Graph Clustering using Diffusion ER - TY - GEN AU - Thies, Michael AU - Gehweiler, Joachim ID - 19018 TI - Thread Migration and Checkpointing in Java ER - TY - CONF AU - Kernbach, Serge AU - Schmickl, Thomas AU - Hamann, Heiko AU - Stradner, Jürgen AU - Schlachter, Florian AU - Schwarzer, Christopher s. F. AU - Winfield, Alan F. T. AU - Matthias, Rene ID - 19023 T2 - Artificial Life XII (ALife XII) TI - Adaptive Action Selection Mechanisms for Evolutionary Multimodular Robotics ER - TY - CONF AU - Briest, Patrick AU - Chalermsook, Parinya AU - Khanna, Sanjeev AU - Laekhanukit, Bundit AU - Nanongkai, Danupon ID - 19029 SN - 0302-9743 T2 - Workshop on Internet and Network Economics (WINE) TI - Improved Hardness of Approximation for Stackelberg Shortest-Path Pricing ER - TY - JOUR AU - Meyer auf der Heide, Friedhelm AU - Scheideler, Christian ID - 1903 IS - 5 JF - Informatik Spektrum TI - Algorithmische Grundlagen verteilter Speichersysteme ER - TY - CONF AU - Briest, Patrick AU - Chawla, Shuchi AU - Kleinberg, Robert AU - Weinberg, S. Matthew ID - 19033 SN - 9780898717013 T2 - Proceedings of the Twenty-First Annual ACM-SIAM Symposium on Discrete Algorithms TI - Pricing Randomized Allocations ER - TY - THES AU - Mahlmann, Peter ID - 19041 SN - 978-3-942647-02-1 TI - Peer-to-peer networks based on random graphs VL - 283 ER - TY - THES AU - Degener, Bastian ID - 19042 SN - 978-3-939350-97-2 TI - Local, distributed approximation algorithms for geometric assignment problems VL - 278 ER - TY - CONF AB - We present a parallel algorithm for the rendering of complex three-dimensional scenes. The algorithm runs across heterogeneous architectures of PC-clusters consisting of a visualization-node, equipped with a powerful graphics adapter, and cluster nodes requiring weaker graphics capabilities only. The visualization-node renders a mixture of scene objects and simplified meshes (Reliefboards). The cluster nodes assist the visualization-node by asynchronous computing of Reliefboards, which are used to replace and render distant parts of the scene. Our algorithm is capable of gaining significant speedups if the cluster's nodes provide weak graphics adapters only. We trade the number of cluster nodes off the scene objects' image quality. AU - Fischer, Matthias AU - Jähn, Claudius AU - Suess, Tim ID - 18136 T2 - Eurographics Symposium on Parallel Graphics and Visualization (EGPGV) TI - Asynchronous Parallel Reliefboard Computation for Scene Object Approximation ER - TY - CONF AB - Many professional cluster systems consist of nodes with different hardware configurations. Such heterogeneous environments require different load-balancing techniques than homogenous environments. The c-load-collision-protocol is able to achieve good results for data-management purposes. Using this protocol, we propose a way for load-balancing in interactive rendering environments. For this work, we implemented a parallel rendering system and took different picking strategies into account to compare the results. The advantage of our approach compared to other approaches is that we group the available nodes of a cluster into two different categories, based on the hardware abilities. Some nodes are used solely for rendering, while others serve as secondary storage and to assist the former ones by performing auxiliary calculations. AU - Suess, Tim AU - Wiesemann, Timo AU - Fischer, Matthias ID - 18289 SN - 9781424481330 T2 - 2010 IEEE Fifth International Conference on Networking, Architecture, and Storage TI - Evaluation of a c-Load-Collision-Protocol for Load-Balancing in Interactive Environments ER - TY - CHAP AB - Typischerweise sind die Knoten eines PC-Clusters nicht mit leistungsfähigen Grafikkarten ausgestattet. Dennoch bieten Cluster-Betreiber einige wenige Rechenknoten an, die mit Highend-Grafikkarten ausgestattet sind, um beispielsweise eine PowerWall zu betreiben. Wenn zwischen diesen unterschiedlichen Knotentypen ein schnelles Netzwerk existiert, kann die Bilderzeugung durch die Knoten mit schwacher Grafikkarte beschleunigt werden. Dabei können die unterschiedlichen Knotentypen unterschiedliche Aufgabe bearbeiten. In einem solchen heterogenen System, müssen die unterschiedlichen entstehenden Lasten auf andere Weise verteilt werden, als in einem System, bei dem alle Knoten gleich ausgestattet sind. Wir präsentieren in dieser Arbeit Lastbalancierungsmechanismen, die in einem parallelen Out-of-Core-Renderingsystem für heterogene PC-Cluster eingesetzt werden. AU - Suess, Tim AU - Wiesemann, Timo AU - Fischer, Matthias ID - 18290 T2 - Augmented & Virtual Reality in der Produktentstehung TI - Gewichtetes c-Collision-Protokoll zur Balancierung eines parallelen Out-of-Core-Renderingsystems ER - TY - CONF AU - Meyer auf der Heide, Friedhelm AU - Phillips, Cynthia A. ID - 16414 SN - 9781450300797 TI - Proceedings of the 22nd ACM symposium on Parallelism in algorithms and architectures - SPAA '10 ER - TY - CHAP AB - We present an approach for real-time rendering of complex 3D scenes consisting of millions of polygons on limited graphics hardware. In a preprocessing step, powerful hardware is used to gain fine granular global visibility information of a scene using an adaptive sampling algorithm. Additively the visual influence of each object on the eventual rendered image is estimated. This influence is used to select the most important objects to display in our approximative culling algorithm. After the visibility data is compressed to meet the storage capabilities of small devices, we achieve an interactive walkthrough of the Power Plant scene on a standard netbook with an integrated graphics chipset. AU - Eikel, Benjamin AU - Jähn, Claudius AU - Fischer, Matthias ID - 16505 SN - 0302-9743 T2 - Advances in Visual Computing TI - Preprocessed Global Visibility for Real-Time Rendering on Low-End Hardware ER - TY - CHAP AU - Degener, Bastian AU - Kempkes, Barbara AU - Kling, Peter AU - Meyer auf der Heide, Friedhelm ID - 16365 SN - 0302-9743 T2 - Structural Information and Communication Complexity TI - A Continuous, Local Strategy for Constructing a Short Chain of Mobile Robots ER - TY - CONF AU - Degener, Bastian AU - Kempkes, Barbara AU - Meyer auf der Heide, Friedhelm ID - 16401 SN - 9781450300797 T2 - Proceedings of the 22nd ACM symposium on Parallelism in algorithms and architectures - SPAA '10 TI - A local O(n2) gathering algorithm ER - TY - BOOK ED - Abramsky, Samson ED - Gavoille, Cyril ED - Kirchner, Claude ED - Meyer auf der Heide, Friedhelm ED - Spirakis, Paul G. ID - 16403 SN - 0302-9743 TI - Automata, Languages and Programming, 37th International Colloquium, ICALP 2010, Bordeaux, France, July 6-10, 2010, Proceedings, Part II. ER - TY - BOOK ED - Abramsky, Samson ED - Gavoille, Cyril ED - Kirchner, Claude ED - Meyer auf der Heide, Friedhelm ED - Spirakis, Paul G. ID - 16404 SN - 0302-9743 TI - Automata, Languages and Programming, 37th International Colloquium, ICALP 2010, Bordeaux, France, July 6-10, 2010, Proceedings, Part I. ER - TY - THES AU - Lürwer-Brüggemeier, Katharina ID - 19605 TI - Mächtigkeit und Komplexität von Berechnungen mit der ganzzahligen Division VL - 261 ER - TY - THES AU - Mense, Mario ID - 19614 SN - 978-3-939350-79-8 TI - On Fault-Tolerant Data Placement in Storage Networks VL - 260 ER - TY - THES AU - Kortenjan, Michael ID - 19617 SN - 978-3-939350-77-4 TI - Size Equivalent Cluster Trees - Rendering CAD Models in Industrial Scenes VL - 258 ER - TY - THES AU - Bonorden, Olaf ID - 19618 SN - 978-3-939350-76-7 TI - Versatility of Bulk Synchronous Parallel Computing: From the Heterogeneous Cluster to the System on Chip VL - 257 ER - TY - GEN AU - Bonorden, Olaf AU - Degener, Bastian AU - Pietrzyk, Peter AU - Kempkes, Barbara ID - 19722 TI - Complexity and approximation of a geometric local robot assignment problem ER - TY - CHAP AB - We introduce a geometric multi-robot assignment problem. Robots positioned in a Euclidean space have to be assigned to treasures in such a way that their joint strength is sufficient to unearth a treasure with a given weight. The robots have a limited range and thus can only be assigned to treasures in their proximity. The objective is to unearth as many treasures as possible. We investigate the complexity of several variants of this problem and show whether they are in $\classP$ or are $\classNP$-complete. Furthermore, we provide a distributed and local constant-factor approximation algorithm using constant-factor resource augmentation for the two-dimensional setting with $\bigO(\log^*n)$ communication rounds. AU - Bonorden, Olaf AU - Degener, Bastian AU - Kempkes, Barbara AU - Pietrzyk, Peter ID - 19724 SN - 0302-9743 T2 - Algorithmic Aspects of Wireless Sensor Networks TI - Complexity and Approximation of a Geometric Local Robot Assignment Problem ER - TY - GEN AB - Categorizing peer-to-peer networks from an algorithmic point of view the two extremes of the spectrum are unstructured networks and networks based on plain distributed hash tables (DHT). Unstructured networks stand out with their simplicity, robustness, and support for complex queries. Though, they lack efficient query algorithms providing guarantees. On the other hand, DHT based networks feature efficient lookup algorithms with typically logarithmic hop distance and provide simple and efficient load balancing. Yet, they are limited to exact match queries and in many cases hard to maintain under churn. AU - Schindelhauer, Christian AU - Mahlmann, Peter AU - Janson, Thomas ID - 19825 TI - 3nuts: A Locality-Aware Peer-to-Peer Network Combining Random Networks, Search Trees, and DHTs ER - TY - JOUR AU - Ooi, Chia Ching AU - Schindelhauer, Christian ID - 19830 JF - Mobile Networks and Applications (MONET) SN - 1383-469X TI - Minimal Energy Path Planning for Wireless Robots ER - TY - JOUR AU - Ooi, Chia Ching AU - Schindelhauer, Christian ID - 19831 JF - Telecommunication Systems SN - 1018-4864 TI - Utilizing detours for energy conservation in mobile wireless networks VL - 43 ER - TY - CONF AU - Raptopoulos, Christoforos L. AU - Nikoletseas, Sotiris E. AU - Spirakis, Paul G. ID - 19901 SN - 9781493928637 T2 - 34st International Symposium on Mathematical Foundations of Computer Science TI - Colouring Non-sparse Random Intersection Graphs ER - TY - CONF AU - Nikoletseas, Sotiris E. AU - Raptopoulos, Christoforos L. AU - Spirakis, Paul G. ID - 19904 T2 - Proceedings of IPDPS - IEEE International Parallel & Distributed Processing Symposium TI - Combinatorial Properties for Efficient Communication in Distributed Networks with Local Interactions ER - TY - CONF AU - Deveci, Deniz AU - Kortenjan, Michael AU - Schomaker, Gunnar ID - 19934 T2 - Parallel and Distributed Computing and Systems, Nr. 21 TI - Distributed Heterogeneous Hashing and Deterministic Dynamical Decompositions ER - TY - CONF AB - One of the prominent challenges in mobile robotics is to develop control methodologies that allow the adaptation to dynamic and unforeseen environments. The classic approach of hand-coded controllers is very efficient for well-defined tasks and specific environments but poor in adapting to changing environmental conditions. One alternative approach is the application of evolutionary algorithms which need, in turn, easily evolvable representations of controllers. In this paper, we investigate one promising approach of an artificial hormone system as a control paradigm which is believed to be easily optimized by evolutionary processes. In a first step of this research, we focus on the simple task of collision avoidance. We present a brief mathematical analysis of this controller approach and an implementation of the controller on a mobile robot to check the feasibility in principle of our approach. The task is successfully accomplished and we conclude with a discussion of the hormone dynamics in the robot. AU - Stradner, Jürgen AU - Hamann, Heiko AU - Schmickl, Thomas AU - Crailsheim, Karl ID - 20254 SN - 9781424438037 T2 - 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems TI - Analysis and implementation of an Artificial Homeostatic Hormone System: A first case study in robotic hardware ER - TY - JOUR AB - By compiling macroscopic models we analyze the adaptive behavior in a swarm of autonomous robots generated by a bio-inspired, distributed control algorithm. We developed two macroscopic models by taking two different perspectives: A Stock & Flow model, which is simple to implement and fast to simulate, and a spatially resolved model based on diffusion processes. These two models were compared concerning their prediction quality and their analytical power: One model allowed easy identification of the major feedback loops governing the swarm behavior. The other model allowed analysis of the expected shapes and positions of observable robot clusters. We found a high correlation in the challenges posed by both modeling techniques and we highlighted the inherent problems of inferring emergent macroscopic rules from a microscopic description of swarm behavior. AU - Schmickl, Thomas AU - Hamann, Heiko AU - Wörn, Heinz AU - Crailsheim, Karl ID - 20255 IS - 9 JF - Robotics and Autonomous Systems SN - 0921-8890 TI - Two different approaches to a macroscopic model of a bio-inspired robotic swarm VL - 6 ER - TY - CONF AU - Hamann, Heiko AU - Troch, Inge AU - Breitenecker, F. ID - 20259 T2 - MATHMOD 2009 - 6th Vienna International Conference on Mathematical Modelling TI - Pattern Formation as a Transient Phenomenon in the Nonlinear Dynamics of a Multi-Agent System ER - TY - JOUR AU - Meyer auf der Heide, Friedhelm AU - Rammig, Franz-Josef ID - 17453 JF - Public Service Review: Science and Technology TI - Self-Organisation and Self-Optimization VL - 04 ER - TY - JOUR AU - Briest, Patrick ID - 19031 IS - 1 JF - it - Information Technology SN - 1611-2776 TI - Algorithmische und komplexitätstheoretische Aspekte kombinatorischer Preisoptimierung (Computational Aspects of Combinatorial Pricing Problems) VL - 51 ER - TY - CHAP AB - In a Stackelberg pricing game a leader aims to set prices on a subset of a given collection of items, such as to maximize her revenue from a follower purchasing a feasible subset of the items. We focus on the case of computationally bounded followers who cannot optimize exactly over the range of all feasible subsets, but apply some publicly known algorithm to determine the set of items to purchase. This corresponds to general multi-dimensional pricing assuming that consumers cannot optimize over the full domain of their valuation functions but still aim to act rationally to the best of their ability. We consider two versions of this novel type of Stackelberg pricing games. Assuming that items are weighted objects and the follower seeks to purchase a min-cost selection of objects of some minimum weight (the Min-Knapsack problem) and uses a simple greedy 2-approximate algorithm, we show how an extension of the known single-price algorithm can be used to derive a polynomial-time (2 + ε)-approximation algorithm for the leader’s revenue maximization problem based on so-called near-uniform price assignments. We also prove the problem to be strongly NP-hard. Considering the case that items are subsets of some ground set which the follower seeks to cover (the Set-Cover problem) via a standard primal-dual approach, we prove that near-uniform price assignments fail to yield a good approximation guarantee. However, in the special case of elements with frequency 2 (the Vertex-Cover problem) it turns out that exact revenue maximization can be done in polynomial-time. This stands in sharp contrast to the fact that revenue maximization becomes APX-hard already for elements with frequency 3. AU - Briest, Patrick AU - Hoefer, Martin AU - Gualà, Luciano AU - Ventre, Carmine ID - 23744 SN - 0302-9743 T2 - Lecture Notes in Computer Science TI - On Stackelberg Pricing with Computationally Bounded Consumers ER - TY - CONF AB - Modern companies are nowadays confronted with an increasing demand of multiple products, where they need to perform more flexible every day. Cost-intensive decisions are to be confirmed in short times, in order to minimize risks and secure efficient production programs as well as material flows. Tools for this digital planning via simulation methods are one well established possibility to receive decision support. Nevertheless, the creation of the necessary simulation models is a complicated and error-prone process, where complexity of modeling, validation and verification depends on the used tool and its functionalities. This paper presents implemented concepts for an innovative user support in his tasks of verification and validation of simulation models during the execution of a simulation run. Time-intensive procedures like stopping simulation, parameterization and restarting within the problem analysis are simplified. So the user is able to focus on the real problem solving task. AU - Laroque, Christoph AU - Fischer, Matthias AU - Dangelmaier, Wilhelm ID - 18138 T2 - European Simulation and Modelling Conference (ESM 2009) TI - Concepts for Model Verification and Validation during Simulation Runtime ER - TY - CHAP AU - Suess, Tim AU - Fischer, Matthias AU - Huber, Daniel AU - Laroque, Christoph AU - Dangelmaier, Wilhelm ID - 18291 T2 - Augmented & Virtual Reality in der Produktentstehung TI - Ein System zur aggregierten Visualisierung verteilter Materialflusssimulationen VL - 252 ER - TY - CONF AB - For a fixed virtual scene (=collection of simplices) S and given observer position p, how many elements of S are weakly visible (i.e. not fully occluded by others) from p? The present work explores the trade-off between query time and preprocessing space for these quantities in 2D: exactly, in the approximate deterministic, and in the probabilistic sense. We deduce the EXISTENCE of an O(m^2/n^2) space data structure for S that, given p and time O(log n), allows to approximate the ratio of occluded segments up to arbitrary constant absolute error; here m denotes the size of the Visibility Graph--which may be quadratic, but typically is just linear in the size n of the scene S. On the other hand, we present a data structure CONSTRUCTIBLE in O(n*log(n)+m^2*polylog(n)/k) preprocessing time and space with similar approximation properties and query time O(k*polylog n), where k