TY - CONF AB - 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. AU - Cord-Landwehr, Andreas AU - Lenzner, Pascal ID - 275 T2 - Proceedings of the 40th Conference on Mathematical Foundations of Computer Science (MFCS) TI - Network Creation Games: Think Global - Act Local ER - TY - GEN AU - Kothe, Nils ID - 277 TI - Multilevel Netzwerk Spiele mit konstanten Entfernungen im Highspeed-Netzwerk ER - TY - CONF AU - Berssenbrügge, Jan AU - Wiederkehr, Olga AU - Jähn, Claudius AU - Fischer, Matthias ID - 17425 T2 - 12. Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung TI - Anbindung des Virtuellen Prototypen an die Partialmodelle intelligenter technischer Systeme VL - 343 ER - TY - CONF AU - Jähn, Claudius AU - Fischer, Matthias AU - Gerges, Maria AU - Berssenbrügge, Jan ID - 17427 T2 - 12. Paderborner Workshop Augmented & Virtual Reality in der Produktentstehung TI - Automatische Ableitung geometrischer Eigenschaften von Bauteilen aus dem 3-D-Polygonmodell VL - 342 ER - TY - BOOK ED - Gausemeier, Jürgen ED - Grafe, Michael ED - Meyer auf der Heide, Friedhelm ID - 17431 TI - Augmented & Virtual Reality in der Produktentstehung: Grundlagen, Methoden und Werkzeuge; Interaktions- und Visualisierungstechniken, Virtual Prototyping intelligenter technischer Systeme mit AR/VR VL - 342 ER - TY - JOUR AB - 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. AU - Cohen, R. AU - Polevoy, Gleb ID - 17657 IS - 99 JF - Cloud Computing, IEEE Transactions on KW - Approximation algorithms KW - Approximation methods KW - Bandwidth KW - Cloud computing KW - Routing KW - Schedules KW - Scheduling SN - 2168-7161 TI - Inter-Datacenter Scheduling of Large Data Flows VL - PP ER - TY - JOUR AB - 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. AU - Bar-Yehuda, Reuven AU - Polevoy, Gleb AU - Rawitz, Dror ID - 17658 JF - Discrete Applied Mathematics KW - Local ratio SN - 0166-218X TI - Bandwidth allocation in cellular networks with multiple interferences VL - 194 ER - TY - CONF AB - We consider online leasing problems in which demands arrive over time and need to be served by leasing resources. We introduce a new model for these problems such that a resource can be leased for K different durations each incurring a different cost (longer leases cost less per time unit). Each demand i can be served anytime between its arrival ai and its deadline ai+di by a leased resource. The objective is to meet all deadlines while minimizing the total leasing costs. This model is a natural generalization of Meyerson’s ParkingPermitProblem (FOCS 2005) in which di=0 for all i. We propose an online algorithm that is Θ(K+dmaxlmin)-competitive where dmax and lmin denote the largest di and the shortest available lease length, respectively. We also extend the SetCoverLeasing problem by deadlines and give a competitive online algorithm which also improves on existing solutions for the original SetCoverLeasing problem. AU - Li, Shouwei AU - Mäcker, Alexander AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören ID - 240 T2 - Proceedings of the 21st Annual International Computing and Combinatorics Conference (COCOON) TI - Towards Flexible Demands in Online Leasing Problems ER - TY - GEN AB - We consider the following variant of the two dimensional gathering problem for swarms of robots: Given a swarm of $n$ indistinguishable, point shaped robots on a two dimensional grid. Initially, the robots form a closed chain on the grid and must keep this connectivity during the whole process of their gathering. Connectivity means, that neighboring robots of the chain need to be positioned at the same or neighboring points of the grid. In our model, gathering means to keep shortening the chain until the robots are located inside a $2\times 2$ subgrid. Our model is completely local (no global control, no global coordinates, no compass, no global communication or vision, \ldots). Each robot can only see its next constant number of left and right neighbors on the chain. This fixed constant is called the \emph{viewing path length}. All its operations and detections are restricted to this constant number of robots. Other robots, even if located at neighboring or the same grid point cannot be detected. Only based on the relative positions of its detectable chain neighbors, a robot can decide to obtain a certain state. Based on this state and their local knowledge, the robots do local modifications to the chain by moving to neighboring grid points without breaking the chain. These modifications are performed without the knowledge whether they lead to a global progress or not. We assume the fully synchronous $\mathcal{FSYNC}$ model. For this problem, we present a gathering algorithm which needs linear time. This result generalizes the result from \cite{hopper}, where an open chain with specified distinguishable (and fixed) endpoints is considered. AU - Abshoff, Sebastian AU - Cord-Landwehr, Andreas AU - Fischer, Matthias AU - Jung, Daniel AU - Meyer auf der Heide, Friedhelm ID - 16449 T2 - arXiv:1510.05454 TI - Gathering a Closed Chain of Robots on a Grid ER - TY - GEN AB - We consider the problem of dominating set-based virtual backbone used for routing in asymmetric wireless ad-hoc networks. These networks have non-uniform transmission ranges and are modeled using the well-established disk graphs. The corresponding graph theoretic problem seeks a strongly connected dominating-absorbent set of minimum cardinality in a digraph. A subset of nodes in a digraph is a strongly connected dominating-absorbent set if the subgraph induced by these nodes is strongly connected and each node in the graph is either in the set or has both an in-neighbor and an out-neighbor in it. Distributed algorithms for this problem are of practical significance due to the dynamic nature of ad-hoc networks. We present a first distributed approximation algorithm, with a constant approximation factor and O(Diam) running time, where Diam is the diameter of the graph. Moreover we present a simple heuristic algorithm and conduct an extensive simulation study showing that our heuristic outperforms previously known approaches for the problem. AU - Abu-Khzam, Faisal N. AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Schubert, Michael ID - 16452 T2 - arXiv:1510.01866 TI - Approximation and Heuristic Algorithms for Computing Backbones in Asymmetric Ad-Hoc Networks ER - TY - CONF AB - Consider n nodes connected to a single coordinator. Each node receives an individual online data stream of numbers and, at any point in time, the coordinator has to know the k nodes currently observing the largest values, for a given k between 1 and n. We design and analyze an algorithm that solves this problem while bounding the amount of messages exchanged between the nodes and the coordinator. Our algorithm employs the idea of using filters which, intuitively speaking, leads to few messages to be sent, if the new input is "similar" to the previous ones. The algorithm uses a number of messages that is on expectation by a factor of O((log {\Delta} + k) log n) larger than that of an offline algorithm that sets filters in an optimal way, where {\Delta} is upper bounded by the largest value observed by any node. AU - Mäcker, Alexander AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm ID - 16460 T2 - Proceedings of the 29th International Parallel and Distributed Processing Symposium (IPDPS) TI - Online Top-k-Position Monitoring of Distributed Data Streams ER - TY - JOUR AU - Degener, Bastian AU - Kempkes, Barbara AU - Kling, Peter AU - Meyer auf der Heide, Friedhelm ID - 16391 JF - ACM Transactions on Parallel Computing SN - 2329-4949 TI - Linear and Competitive Strategies for Continuous Robot Formation Problems ER - TY - GEN AB - In the gathering problem, n autonomous robots have to meet on a single point. We consider the gathering of a closed chain of point-shaped, anonymous robots on a grid. The robots only have local knowledge about a constant number of neighboring robots along the chain in both directions. Actions are performed in the fully synchronous time model FSYNC. Every robot has a limited memory that may contain one timestamp of the global clock, also visible to its direct neighbors. In this synchronous time model, there is no limited view gathering algorithm known to perform better than in quadratic runtime. The configurations that show the quadratic lower bound are closed chains. In this paper, we present the first sub-quadratic---in fact linear time---gathering algorithm for closed chains on a grid. AU - Abshoff, Sebastian AU - Andreas Cord-Landwehr, Andreas AU - Jung, Daniel AU - Meyer auf der Heide, Friedhelm ID - 16397 T2 - ArXiv: 1501.04877 TI - Towards Gathering Robots with Limited View in Linear Time: The Closed Chain Case ER - TY - CONF AU - Hamann, Heiko AU - Karsai, Istvan AU - Schmickl, Thomas AU - Hilbun, Allison ID - 20007 T2 - Symposium on Biomathematics and Ecology: Education and Research TI - The common stomach: Organizing task allocation in wasp societies ER - TY - CONF AU - Hamann, Heiko AU - Valentini, Gabriele ID - 20008 SN - 0302-9743 T2 - Ninth Int. Conf. on Swarm Intelligence (ANTS 2014) TI - Swarm in a Fly Bottle: Feedback-Based Analysis of Self-organizing Temporary Lock-ins ER - TY - JOUR AB - A grand challenge in the field of artificial life is to find a general theory of emergent self-organizing systems. In swarm systems most of the observed complexity is based on motion of simple entities. Similarly, statistical mechanics focuses on collective properties induced by the motion of many interacting particles. In this article we apply methods from statistical mechanics to swarm systems. We try to explain the emergent behavior of a simulated swarm by applying methods based on the fluctuation theorem. Empirical results indicate that swarms are able to produce negative entropy within an isolated subsystem due to frozen accidents. Individuals of a swarm are able to locally detect fluctuations of the global entropy measure and store them, if they are negative entropy productions. By accumulating these stored fluctuations over time the swarm as a whole is producing negative entropy and the system ends up in an ordered state. We claim that this indicates the existence of an inverted fluctuation theorem for emergent self-organizing dissipative systems. This approach bears the potential of general applicability. AU - Hamann, Heiko AU - Schmickl, Thomas AU - Crailsheim, Karl ID - 20120 IS - 1 JF - Artificial Life TI - Analysis of Swarm Behaviors Based on an Inversion of the Fluctuation Theorem VL - 20 ER - TY - CONF AB - Collective decision making in self-organized systems is challenging because it relies on local perception and local communication. Globally defined qualities such as consensus time and decision accuracy are both difficult to predict and difficult to guarantee. We present the weighted voter model which implements a self-organized collective decision making process. We provide an ODE model, a master equation model (numerically solved by the Gillespie algorithm), and agent-based simulations of the proposed decision-making strategy. This set of models enables us to investigate the system behavior in the thermodynamic limit and to investigate finite-size effects due to random fluctuations. Based on our results, we give minimum requirements to guarantee consensus on the optimal decision, a minimum swarm size to guarantee a certain accuracy, and we show that the proposed approach scales with system size and is robust to noise. AU - Dorigo, Marco AU - Hamann, Heiko AU - Valentini, Gabriele AU - Lomuscio, Alessio AU - Scerri, Paul AU - Bazzan, Ana AU - Huhns, Michael ID - 20121 T2 - Proceedings of the 13th Int. Conf. on Autonomous Agents and Multiagent Systems (AAMAS 2014) TI - Self-Organized Collective Decision Making: The Weighted Voter Model ER - TY - CONF AU - Hamann, Heiko ID - 20126 T2 - Int. Conf. on Genetic and Evolutionary Computation (GECCO 2014) TI - Evolving Prediction Machines: Collective Behaviors Based on Minimal Surprisal ER - TY - CONF AU - Birattari, Mauro AU - Dorigo, Marco AU - Hamann, Heiko AU - Garnier, Simon AU - Montes de Oca, Marco AU - Solnon, Christine AU - Stuetzle, Thomas AU - Ding, Hongli ID - 20127 T2 - Ninth Int. Conf. on Swarm Intelligence (ANTS 2014) TI - Sorting in Swarm Robots Using Communication-Based Cluster Size Estimation VL - 8667 ER - TY - CHAP AU - Khaluf, Yara AU - Dorigo, Marco AU - Hamann, Heiko AU - Valentini, Gabriele AU - Bartz-Beielstein, T. ID - 20128 T2 - 13th International Conference on Parallel Problem Solving from Nature (PPSN 2014) TI - Derivation of a Micro-Macro Link for Collective Decision-Making Systems: Uncover Network Features Based on Drift Measurements VL - 8672 ER -