TY - CONF AB - Resolving distributed attacks benefits from collaboration between networks. We present three approaches for the same multi-domain defensive action that can be applied in such an alliance: 1) Counteract Everywhere, 2) Minimize Countermeasures, and 3) Minimize Propagation. First, we provide a formula to compute efficiency of a defense; then we use this formula to compute the efficiency of the approaches under various circumstances. Finally, we discuss how task execution order and timing influence defense efficiency. Our results show that the Minimize Propagation approach is the most efficient method when defending against the chosen attack. AU - Koning, Ralph AU - Polevoy, Gleb AU - Meijer, Lydia AU - de Laat, Cees AU - Grosso, Paola ID - 17667 KW - computer network security KW - multinetwork environments KW - multidomain defensive action KW - task execution order KW - timing influence defense efficiency KW - distributed attacks KW - collaborative security defence approach KW - minimize propagation approach KW - minimize countermeasure approach KW - counteract everywhere approach KW - Conferences KW - Cloud computing KW - Computer crime KW - Edge computing KW - Security KW - Defense Approaches KW - Multi-Domain Defense KW - Collaborative Defense KW - Defense Algorithms KW - Computer Networks SN - null T2 - 2019 6th IEEE International Conference on Cyber Security and Cloud Computing (CSCloud)/ 2019 5th IEEE International Conference on Edge Computing and Scalable Cloud (EdgeCom) TI - Approaches for Collaborative Security Defences in Multi Network Environments ER - TY - THES AU - Malatyali, Manuel ID - 18975 TI - Big Data: Sublinear Algorithms for Distributed Data Streams ER - TY - THES AB - This thesis investigates approximate pure Nash equilibria in different game-theoretic models. In such an outcome, no player can improve her objective by more than a given factor through a deviation to another strategy. In the first part, we investigate two variants of Congestion Games in which the existence of pure Nash equilibria is guaranteed through a potential function argument. However, the computation of such equilibria might be hard. We construct and analyze approximation algorithms that enable the computation of states with low approximation factors in polynomial time. To show their guarantees we use sub games among players, bound the potential function values of arbitrary states and exploit a connection between Shapley and proportional cost shares. Furthermore, we apply and analyze sampling techniques for the computation of approximate Shapley values in different settings. In the second part, we concentrate on the existence of approximate pure Nash equilibria in games in which no pure Nash equilibria exist in general. In the model of Coevolving Opinion Formation Games, we bound the approximation guarantees for natural states nearly independent of the specific definition of the players' neighborhoods by applying a concept of virtual costs. For the special case of only one influential neighbor, we even show lower approximation factors for a natural strategy. Then, we investigate a two-sided Facility Location Game among facilities and clients on a line with an objective function consisting of distance and load. We show tight bounds on the approximation factor for settings with three facilities and infinitely many clients. For the general scenario with an arbitrary number of facilities, we bound the approximation factor for two promising candidates, namely facilities that are uniformly distributed and which are paired. AU - Feldotto, Matthias ID - 8080 TI - Approximate Pure Nash Equilibria in Congestion, Opinion Formation and Facility Location Games ER - TY - CONF AU - Jansen, Klaus AU - Maack, Marten AU - Mäcker, Alexander ID - 8866 T2 - Proceedings of the 33rd IEEE International Parallel and Distributed Processing Symposium (IPDPS) TI - Scheduling on (Un-)Related Machines with Setup Times ER - TY - CONF AB - We characterise the set of dominant strategy incentive compatible (DSIC), strongly budget balanced (SBB), and ex-post individually rational (IR) mechanisms for the multi-unit bilateral trade setting. In such a setting there is a single buyer and a single seller who holds a finite number k of identical items. The mechanism has to decide how many units of the item are transferred from the seller to the buyer and how much money is transferred from the buyer to the seller. We consider two classes of valuation functions for the buyer and seller: Valuations that are increasing in the number of units in possession, and the more specific class of valuations that are increasing and submodular. Furthermore, we present some approximation results about the performance of certain such mechanisms, in terms of social welfare: For increasing submodular valuation functions, we show the existence of a deterministic 2-approximation mechanism and a randomised e/(1-e) approximation mechanism, matching the best known bounds for the single-item setting. AU - Lazos, Philip AU - Goldberg, Paul AU - Skopalik, Alexander AU - Gerstgrasser, Matthias AU - de Keijzer, Bart ID - 5471 T2 - Proceedings of the Thirty-Third AAAI Conference on Artificial Intelligence (AAAI) TI - Multi-unit Bilateral Trade ER - TY - CONF AU - Feldkord, Björn AU - Knollmann, Till AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm ID - 12870 T2 - Proceedings of the 17th Workshop on Approximation and Online Algorithms (WAOA) TI - Managing Multiple Mobile Resources ER - TY - THES AU - Mäcker, Alexander ID - 14851 TI - On Scheduling with Setup Times ER - TY - GEN AB - We present a technique for rendering highly complex 3D scenes in real-time by generating uniformly distributed points on the scene's visible surfaces. The technique is applicable to a wide range of scene types, like scenes directly based on complex and detailed CAD data consisting of billions of polygons (in contrast to scenes handcrafted solely for visualization). This allows to visualize such scenes smoothly even in VR on a HMD with good image quality, while maintaining the necessary frame-rates. In contrast to other point based rendering methods, we place points in an approximated blue noise distribution only on visible surfaces and store them in a highly GPU efficient data structure, allowing to progressively refine the number of rendered points to maximize the image quality for a given target frame rate. Our evaluation shows that scenes consisting of a high amount of polygons can be rendered with interactive frame rates with good visual quality on standard hardware. AU - Brandt, Sascha AU - Jähn, Claudius AU - Fischer, Matthias AU - Meyer auf der Heide, Friedhelm ID - 16341 T2 - arXiv:1904.08225 TI - Rendering of Complex Heterogenous Scenes using Progressive Blue Surfels ER - TY - JOUR AU - Feldkord, Björn AU - Meyer auf der Heide, Friedhelm ID - 13873 IS - 3 JF - ACM Transactions on Parallel Computing (TOPC) TI - The Mobile Server Problem VL - 6 ER - TY - JOUR AU - Meyer auf der Heide, Friedhelm ID - 13937 IS - 2 JF - Mathematische Semesterberichte TI - Paul Curzon, Peter W. McOwan: Computational Thinking; Die Welt des algorithmischen Denkens – in Spielen, Zaubertricks und Rätseln VL - 66 ER - TY - CHAP AU - Kling, Peter AU - Meyer auf der Heide, Friedhelm ID - 13939 T2 - Distributed Computing by Mobile Entities, Current Research in Moving and Computing TI - Continuous Protocols for Swarm Robotics VL - 11340 ER - TY - CONF AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm ID - 13942 T2 - Proceedings of the 8th International Conference on Operations Research and Enterprise Systems TI - Online Algorithms for Leasing Vertex Cover and Leasing Non-metric Facility Location ER - TY - JOUR AU - Abu-Khzam, Faisal N. AU - Li, Shouwei AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Podlipyan, Pavel ID - 13946 JF - Theoretical Computer Science TI - Efficient parallel algorithms for parameterized problems VL - 786 ER - TY - CONF AU - Castenow, Jannik AU - Kolb, Christina AU - Scheideler, Christian ID - 14539 T2 - Proceedings of the 26th International Colloquium on Structural Information and Communication Complexity (SIROCCO) TI - A Bounding Box Overlay for Competitive Routing in Hybrid Communication Networks ER - TY - CONF AB - Competing firms tend to select similar locations for their stores. This phenomenon, called the principle of minimum differentiation, was captured by Hotelling with a landmark model of spatial competition but is still the object of an ongoing scientific debate. Although consistently observed in practice, many more realistic variants of Hotelling's model fail to support minimum differentiation or do not have pure equilibria at all. In particular, it was recently proven for a generalized model which incorporates negative network externalities and which contains Hotelling's model and classical selfish load balancing as special cases, that the unique equilibria do not adhere to minimum differentiation. Furthermore, it was shown that for a significant parameter range pure equilibria do not exist. We derive a sharp contrast to these previous results by investigating Hotelling's model with negative network externalities from an entirely new angle: approximate pure subgame perfect equilibria. This approach allows us to prove analytically and via agent-based simulations that approximate equilibria having good approximation guarantees and that adhere to minimum differentiation exist for the full parameter range of the model. Moreover, we show that the obtained approximate equilibria have high social welfare. AU - Feldotto, Matthias AU - Lenzner, Pascal AU - Molitor, Louise AU - Skopalik, Alexander ID - 10281 T2 - Proceedings of the 18th International Conference on Autonomous Agents and MultiAgent Systems TI - From Hotelling to Load Balancing: Approximation and the Principle of Minimum Differentiation ER - TY - GEN AU - Pukrop, Simon ID - 10344 TI - Scheduling Algorithms for Multi-Operation Jobs with Setups on a Single Machine ER - TY - CONF AB - We study the classic bin packing problem in a fully-dynamic setting, where new items can arrive and old items may depart. We want algorithms with low asymptotic competitive ratio while repacking items sparingly between updates. Formally, each item i has a movement cost c_i >= 0, and we want to use alpha * OPT bins and incur a movement cost gamma * c_i, either in the worst case, or in an amortized sense, for alpha, gamma as small as possible. We call gamma the recourse of the algorithm. This is motivated by cloud storage applications, where fully-dynamic bin packing models the problem of data backup to minimize the number of disks used, as well as communication incurred in moving file backups between disks. Since the set of files changes over time, we could recompute a solution periodically from scratch, but this would give a high number of disk rewrites, incurring a high energy cost and possible wear and tear of the disks. In this work, we present optimal tradeoffs between number of bins used and number of items repacked, as well as natural extensions of the latter measure. AU - Feldkord, Björn AU - Feldotto, Matthias AU - Gupta, Anupam AU - Guruganesh, Guru AU - Kumar, Amit AU - Riechers, Sören AU - Wajc, David ED - Chatzigiannakis, Ioannis ED - Kaklamanis, Christos ED - Marx, Dániel ED - Sannella, Donald ID - 2484 SN - 1868-8969 T2 - 45th International Colloquium on Automata, Languages, and Programming (ICALP 2018) TI - Fully-Dynamic Bin Packing with Little Repacking VL - 107 ER - TY - CONF AU - Feldkord, Björn AU - Meyer auf der Heide, Friedhelm ID - 2485 T2 - Proceedings of the 30th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - Online Facility Location with Mobile Facilities ER - TY - GEN AB - We consider a group of $n$ autonomous mobile robots of which $m$ are stationary thus cannot move. Robots are represented by points in the Euclidean plane. They have no memory, do not communicate or share a common coordinate system and they move solely based on the positioning of other robots within their limited viewing range of 1. The goal is to gather the robots inside of the convex hull of all stationary robots. A variant of this problem, the general gathering problem, has been studied in various different time models. In this work, we consider a continuous time model, where robots continuously observe their neighbors, compute the next target of movement and move with a speed limit of 1 at any time. Regarding the robots' local strategy, we only study contracting algorithms in which every robot that is positioned on the border of the convex hull of all robots moves into this hull. We present a time bound of $\mathcal{O}(nd)$ for any general contracting algorithms in a configuration with only a single stationary robot. For configurations with more stationary robots, we prove that robots converge against the convex hull of all stationary robots and that no upper bound on the runtime exists. For the specific contracting algorithms Go-To-The-Left, Go-On-Bisector and Go-To-The-Middle, we provide linear time bounds. AU - Liedtke, David Jan ID - 25121 TI - Influence of Stationary Robots on Continuous Robot Formation Problems ER - TY - GEN AB - We introduce the \emph{Online Connected Dominating Set Leasing} problem (OCDSL) in which we are given an undirected connected graph $G = (V, E)$, a set $\mathcal{L}$ of lease types each characterized by a duration and cost, and a sequence of subsets of $V$ arriving over time. A node can be leased using lease type $l$ for cost $c_l$ and remains active for time $d_l$. The adversary gives in each step $t$ a subset of nodes that need to be dominated by a connected subgraph consisting of nodes active at time $t$. The goal is to minimize the total leasing costs. OCDSL contains the \emph{Parking Permit Problem}~\cite{PPP} as a special subcase and generalizes the classical offline \emph{Connected Dominating Set} problem~\cite{Guha1998}. It has an $\Omega(\log ^2 n + \log |\mathcal{L}|)$ randomized lower bound resulting from lower bounds for the \emph{Parking Permit Problem} and the \emph{Online Set Cover} problem~\cite{Alon:2003:OSC:780542.780558,Korman}, where $|\mathcal{L}|$ is the number of available lease types and $n$ is the number of nodes in the input graph. We give a randomized $\mathcal{O}(\log ^2 n + \log |\mathcal{L}| \log n)$-competitive algorithm for OCDSL. We also give a deterministic algorithm for a variant of OCDSL in which the dominating subgraph need not be connected, the \emph{Online Dominating Set Leasing} problem. The latter is based on a simple primal-dual approach and has an $\mathcal{O}(|\mathcal{L}| \cdot \Delta)$-competitive ratio, where $\Delta$ is the maximum degree of the input graph. AU - Markarian, Christine ID - 19978 T2 - arXiv:1805.02994 TI - Online Connected Dominating Set Leasing ER - TY - CONF AB - We consider a market where final products or services are compositions of a number of basic services. Users are asked to evaluate the quality of the composed product after purchase. The quality of the basic service influences the performance of the composed services but cannot be observed directly. The question we pose is whether it is possible to use user evaluations on composed services to assess the quality of basic services. We discuss how to combine aggregation of evaluations across users and disaggregation of information on composed services to derive valuations for the single components. As a solution we propose to use the (weighted) average as aggregation device in connection with the Shapley value as disaggregation method, since this combination fulfills natural requirements in our context. In addition, we address some occurring computational issues: We give an approximate solution concept using only a limited number of evaluations which guarantees nearly optimal results with reduced running time. Lastly, we show that a slightly modified Shapley value and the weighted average are still applicable if the evaluation profiles are incomplete. AU - Feldotto, Matthias AU - Haake, Claus-Jochen AU - Skopalik, Alexander AU - Stroh-Maraun, Nadja ID - 2831 SN - 978-1-4503-5916-0 T2 - Proceedings of the 13th Workshop on Economics of Networks, Systems and Computation (NetEcon 2018) TI - Disaggregating User Evaluations Using the Shapley Value ER - TY - JOUR AU - Li, Shouwei AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm ID - 2848 IS - 5 JF - Algorithmica TI - Towards Flexible Demands in Online Leasing Problems. VL - 80 ER - TY - JOUR AU - Abu-Khzam, Faisal N. AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Schubert, Michael ID - 2849 JF - Theory of Computing Systems TI - Approximation and Heuristic Algorithms for Computing Backbones in Asymmetric Ad-hoc Networks ER - TY - CONF AU - Hamann, Heiko AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Wahby, Mostafa ID - 2850 T2 - Ninth International Conference on Fun with Algorithms (FUN) TI - Pick, Pack, & Survive: Charging Robots in a Modern Warehouse based on Online Connected Dominating Sets ER - TY - CONF AB - We study the Online Prize-collecting Node-weighted Steiner Forest problem (OPC-NWSF) in which we are given an undirected graph \(G=(V, E)\) with \(|V| = n\) and node-weight function \(w: V \rightarrow \mathcal {R}^+\). A sequence of k pairs of nodes of G, each associated with a penalty, arrives online. OPC-NWSF asks to construct a subgraph H such that each pair \(\{s, t\}\) is either connected (there is a path between s and t in H) or its associated penalty is paid. The goal is to minimize the weight of H and the total penalties paid. The current best result for OPC-NWSF is a randomized \(\mathcal {O}(\log ^4 n)\)-competitive algorithm due to Hajiaghayi et al. (ICALP 2014). We improve this by proposing a randomized \(\mathcal {O}(\log n \log k)\)-competitive algorithm for OPC-NWSF, which is optimal up to constant factor since OPC-NWSF has a randomized lower bound of \(\varOmega (\log ^2 n)\) due to Korman [11]. Moreover, our result also implies an improvement for two special cases of OPC-NWSF, the Online Prize-collecting Node-weighted Steiner Tree problem (OPC-NWST) and the Online Node-weighted Steiner Forest problem (ONWSF). In OPC-NWST, there is a distinguished node which is one of the nodes in each pair. In ONWSF, all penalties are set to infinity. The currently best known results for OPC-NWST and ONWSF are a randomized \(\mathcal {O}(\log ^3 n)\)-competitive algorithm due to Hajiaghayi et al. (ICALP 2014) and a randomized \(\mathcal {O}(\log n \log ^2 k)\)-competitive algorithm due to Hajiaghayi et al. (FOCS 2013), respectively. AU - Markarian, Christine ID - 24396 SN - 0302-9743 T2 - International Workshop on Combinatorial Algorithms (IWOCA) TI - An Optimal Algorithm for Online Prize-Collecting Node-Weighted Steiner Forest ER - TY - JOUR AU - König, Jürgen AU - Mäcker, Alexander AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören ID - 3551 IS - 4 JF - Journal of Combinatorial Optimization TI - Scheduling with interjob communication on parallel processors VL - 36 ER - TY - GEN AU - Koop, Samuel ID - 3851 TI - Congestion Games mit gewichteten Strategien ER - TY - CONF AB - Consider mitigating the effects of denial of service or of malicious traffic in networks by deleting edges. Edge deletion reduces the DoS or the number of the malicious flows, but it also inadvertently removes some of the desired flows. To model this important problem, we formulate two problems: (1) remove all the undesirable flows while minimizing the damage to the desirable ones and (2) balance removing the undesirable flows and not removing too many of the desirable flows. We prove these problems are equivalent to important theoretical problems, thereby being important not only practically but also theoretically, and very hard to approximate in a general network. We employ reductions to nonetheless approximate the problem and also provide a greedy approximation. When the network is a tree, the problems are still MAX SNP-hard, but we provide a greedy-based 2l-approximation algorithm, where l is the longest desirable flow. We also provide an algorithm, approximating the first and the second problem within {\$}{\$}2 {\backslash}sqrt{\{} 2{\backslash}left| E {\backslash}right| {\}}{\$}{\$}and {\$}{\$}2 {\backslash}sqrt{\{}2 ({\backslash}left| E {\backslash}right| + {\backslash}left| {\backslash}text {\{}undesirable flows{\}} {\backslash}right| ){\}}{\$}{\$}, respectively, where E is the set of the edges of the network. We also provide a fixed-parameter tractable (FPT) algorithm. Finally, if the tree has a root such that every flow in the tree flows on the path from the root to a leaf, we solve the problem exactly using dynamic programming. AU - Polevoy, Gleb AU - Trajanovski, Stojan AU - Grosso, Paola AU - de Laat, Cees ED - Kim, Donghyun ED - Uma, R. N. ED - Zelikovsky, Alexander ID - 17651 KW - flow KW - Red-Blue Set Cover KW - Positive-Negative Partial Set Cover KW - approximation KW - tree KW - MAX SNP-hard KW - root KW - leaf KW - dynamic programming KW - FPT SN - 978-3-030-04651-4 T2 - Combinatorial Optimization and Applications TI - Removing Undesirable Flows by Edge Deletion ER - TY - JOUR AB - Software Defined Networks (SDN) and Network Function Virtualisation (NFV) provide the basis for autonomous response and mitigation against attacks on networked computer infrastructures. We propose a new framework that uses SDNs and NFV to achieve this goal: Secure Autonomous Response Network (SARNET). In a SARNET, an agent running a control loop constantly assesses the security state of the network by means of observables. The agent reacts to and resolves security problems, while learning from its previous decisions. Two main metrics govern the decision process in a SARNET: impact and efficiency; these metrics can be used to compare and evaluate countermeasures and are the building blocks for self-learning SARNETs that exhibit autonomous response. In this paper we present the software implementation of the SARNET framework, evaluate it in a real-life network and discuss the tradeoffs between parameters used by the SARNET agent and the efficiency of its actions. AU - Koning, R. AU - de Graaff, B. AU - Polevoy, Gleb AU - Meijer, R. AU - de Laat, C. AU - Grosso, P. ID - 17666 JF - Future Generation Computer Systems KW - Software defined networks KW - Network function virtualization KW - Cyber attacks KW - Cyber security KW - Defense efficiency KW - Overlay networks SN - 0167-739X TI - Measuring the efficiency of SDN mitigations against attacks on computer infrastructures ER - TY - JOUR AU - Althaus, Ernst AU - Brinkmann, Andre AU - Kling, Peter AU - Meyer auf der Heide, Friedhelm AU - Nagel, Lars AU - Riechers, Sören AU - Sgall, Jiri AU - Suess, Tim ID - 63 IS - 1 JF - Journal of Scheduling TI - Scheduling Shared Continuous Resources on Many-Cores VL - 21 ER - TY - CONF AB - While a lot of research in distributed computing has covered solutions for self-stabilizing computing and topologies, there is far less work on self-stabilization for distributed data structures. Considering crashing peers in peer-to-peer networks, it should not be taken for granted that a distributed data structure remains intact. In this work, we present a self-stabilizing protocol for a distributed data structure called the hashed Patricia Trie (Kniesburges and Scheideler WALCOM'11) that enables efficient prefix search on a set of keys. The data structure has a wide area of applications including string matching problems while offering low overhead and efficient operations when embedded on top of a distributed hash table. Especially, longest prefix matching for $x$ can be done in $\mathcal{O}(\log |x|)$ hash table read accesses. We show how to maintain the structure in a self-stabilizing way. Our protocol assures low overhead in a legal state and a total (asymptotically optimal) memory demand of $\Theta(d)$ bits, where $d$ is the number of bits needed for storing all keys. AU - Knollmann, Till AU - Scheideler, Christian ED - Izumi, Taisuke ED - Kuznetsov, Petr ID - 4411 KW - Self-Stabilizing KW - Prefix Search KW - Distributed Data Structure T2 - Proceedings of the 20th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS) TI - A Self-Stabilizing Hashed Patricia Trie VL - 11201 ER - TY - CONF AB - Routing is a challenging problem for wireless ad hoc networks, especially when the nodes are mobile and spread so widely that in most cases multiple hops are needed to route a message from one node to another. In fact, it is known that any online routing protocol has a poor performance in the worst case, in a sense that there is a distribution of nodes resulting in bad routing paths for that protocol, even if the nodes know their geographic positions and the geographic position of the destination of a message is known. The reason for that is that radio holes in the ad hoc network may require messages to take long detours in order to get to a destination, which are hard to find in an online fashion. In this paper, we assume that the wireless ad hoc network can make limited use of long-range links provided by a global communication infrastructure like a cellular infrastructure or a satellite in order to compute an abstraction of the wireless ad hoc network that allows the messages to be sent along near-shortest paths in the ad hoc network. We present distributed algorithms that compute an abstraction of the ad hoc network in $\mathcal{O}\left(\log ^2 n\right)$ time using long-range links, which results in $c$-competitive routing paths between any two nodes of the ad hoc network for some constant $c$ if the convex hulls of the radio holes do not intersect. We also show that the storage needed for the abstraction just depends on the number and size of the radio holes in the wireless ad hoc network and is independent on the total number of nodes, and this information just has to be known to a few nodes for the routing to work. AU - Jung, Daniel AU - Kolb, Christina AU - Scheideler, Christian AU - Sundermeier, Jannik ID - 4563 KW - greedy routing KW - ad hoc networks KW - convex hulls KW - c-competitiveness T2 - Proceedings of the 14th International Symposium on Algorithms and Experiments for Wireless Networks (ALGOSENSORS) TI - Competitive Routing in Hybrid Communication Networks ER - TY - CONF AU - Jung, Daniel AU - Kolb, Christina AU - Scheideler, Christian AU - Sundermeier, Jannik ID - 4565 SN - 9781450357999 T2 - Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - Brief Announcement: Competitive Routing in Hybrid Communication Networks ER - TY - CONF AU - Meyer auf der Heide, Friedhelm AU - Schaefer, Johannes Sebastian ID - 7570 SN - 9781450357999 T2 - Proceedings of the 30th on Symposium on Parallelism in Algorithms and Architectures - SPAA '18 TI - Brief Announcement: Communication in Systems of Home Based Mobile Agents ER - TY - CONF AB - We present a peer-to-peer network that supports the efficient processing of orthogonal range queries $R=\bigtimes_{i=1}^{d}[a_i,\,b_i]$ in a $d$-dimensional point space.\\ The network is the same for each dimension, namely a distance halving network like the one introduced by Naor and Wieder (ACM TALG'07). We show how to execute such range queries using $\mathcal{O}\left(2^{d'}d\,\log m + d\,|R|\right)$ hops (and the same number of messages) in total. Here $[m]^d$ is the ground set, $|R|$ is the size and $d'$ the dimension of the queried range. Furthermore, if the peers form a distributed network, the query can be answered in $\mathcal{O}\left(d\,\log m + d\,\sum_{i=1}^{d}(b_i-a_i+1)\right)$ communication rounds. Our algorithms are based on a mapping of the Hilbert Curve through $[m]^d$ to the peers. AU - Benter, Markus AU - Knollmann, Till AU - Meyer auf der Heide, Friedhelm AU - Setzer, Alexander AU - Sundermeier, Jannik ID - 4375 KW - Distributed Storage KW - Multi-Dimensional Range Queries KW - Peer-to-Peer KW - Hilbert Curve T2 - Proceedings of the 4th International Symposium on Algorithmic Aspects of Cloud Computing (ALGOCLOUD) TI - A Peer-to-Peer based Cloud Storage supporting orthogonal Range Queries of arbitrary Dimension ER - TY - GEN AU - Geromel, Marcel ID - 5403 TI - Mobile Facility Leasing ER - TY - GEN AU - Kolpaczki, Patrick Irenäus ID - 5404 TI - Online Algorithmen für das k-Page Migration Problem ER - TY - JOUR AB - We study a new class of games which generalizes congestion games andits bottleneck variant. We introduce congestion games with mixed objectives to modelnetwork scenarios in which players seek to optimize for latency and bandwidths alike.We characterize the (non-)existence of pure Nash equilibria (PNE), the convergenceof improvement dynamics, the quality of equilibria and show the complexity of thedecision problem. For games that do not possess PNE we give bounds on the approx-imation ratio of approximate pure Nash equilibria. AU - Feldotto, Matthias AU - Leder, Lennart AU - Skopalik, Alexander ID - 669 IS - 4 JF - Journal of Combinatorial Optimization SN - 1382-6905 TI - Congestion games with mixed objectives VL - 36 ER - TY - GEN AU - Kemper, Arne ID - 1186 TI - Pure Nash Equilibria in Robust Congestion Games via Potential Functions ER - TY - GEN AU - Nachtigall, Marcel ID - 1187 TI - Scenario-driven Strategy Analysis in a n-player Composition Game Model ER - TY - GEN AU - Kempf, Jérôme ID - 1188 TI - Learning deterministic bandit behaviour form compositions ER - TY - THES AB - My dissertation deals with the Gathering problem for swarms of n point-shaped robots on a grid, in which all robots of the swarm are supposed to gather at a previously undefined point. Special attention is paid to the strong limitation of robot capabilities. These include in particular the lack of global control, a global compass, global visibility and (global) communication skills. Furthermore, all robots are identical. The robots are given only local abilities. This includes a constant range of vision. The robots all work completely synchronously. In this work we present and analyze three different Gathering strategies in different robot models. We formally prove correctness and total running time: Chapter 4 focuses on minimizing the available robot capabilities. The underlying strategy completes the gathering in O(n^2) time. For the following Chapters 5 and 6, the aim is to optimize the total running time under using only local robot capabilities: We additionally allow a constant-sized memory and a constant number of locally visible statuses (lights, flags). For the strategies of both chapters we show an asymptotically optimal running time of O(n). Unlike in Chapters 4 and 5, we additionally restrict connectivity and vision to an initially given chain connectivity in Chapter 6, where two chain neighbors must have a distance of 1 from each other. A robot can only see and interact with a constant number of its direct chain neighbors. AU - Jung, Daniel ID - 1209 SN - 978-3-942647-99-1 TI - Local Strategies for Swarm Formations on a Grid ER - TY - CHAP AU - Feldkord, Björn AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm ID - 16392 SN - 0302-9743 T2 - Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications TI - A Dynamic Distributed Data Structure for Top-k and k-Select Queries ER - TY - JOUR AB - In budget games, players compete over resources with finite budgets. For every resource, a player has a specific demand and as a strategy, he chooses a subset of resources. If the total demand on a resource does not exceed its budget, the utility of each player who chose that resource equals his demand. Otherwise, the budget is shared proportionally. In the general case, pure Nash equilibria (NE) do not exist for such games. In this paper, we consider the natural classes of singleton and matroid budget games with additional constraints and show that for each, pure NE can be guaranteed. In addition, we introduce a lexicographical potential function to prove that every matroid budget game has an approximate pure NE which depends on the largest ratio between the different demands of each individual player. AU - Drees, Maximilian AU - Feldotto, Matthias AU - Riechers, Sören AU - Skopalik, Alexander ID - 1369 JF - Journal of Combinatorial Optimization SN - 1382-6905 TI - Pure Nash equilibria in restricted budget games ER - TY - THES AU - Li, Shouwei ID - 19604 TI - Parallel fixed parameter tractable problems ER - TY - CONF AU - Markarian, Christine ID - 2851 T2 - International Conference on Operations Research (OR) TI - Leasing with Uncertainty ER - TY - CONF AB - Through this study, we introduce the idea of applying scheduling techniques to allocate spatial resources that are shared among multiple robots moving in a static environment and having temporal constraints on the arrival time to destinations. To illustrate this idea, we present an exemplified algorithm that plans and assigns a motion path to each robot. The considered problem is particularly challenging because: (i) the robots share the same environment and thus the planner must take into account overlapping paths which cannot happen at the same time; (ii) there are time deadlines thus the planner must deal with temporal constraints; (iii) new requests arrive without a priori knowledge thus the planner must be able to add new paths online and adjust old plans; (iv) the robot motion is subject to noise thus the planner must be reactive to adapt to online changes. We showcase the functioning of the proposed algorithm through a set of agent-based simulations. AU - Khaluf, Yara AU - Markarian, Christine AU - Simoens, Pieter AU - Reina, Andreagiovanni ID - 24398 SN - 0302-9743 T2 - International Conference on Practical Applications of Agents and Multi-Agent Systems (PAAMS 2017) TI - Scheduling Access to Shared Space in Multi-robot Systems ER - TY - CONF AB - We study a model of selfish resource allocation that seeks to incorporate dependencies among resources as they exist in in modern networked environments. Our model is inspired by utility functions with constant elasticity of substitution (CES) which is a well-studied model in economics. We consider congestion games with different aggregation functions. In particular, we study $L_p$ norms and analyze the existence and complexity of (approximate) pure Nash equilibria. Additionally, we give an almost tight characterization based on monotonicity properties to describe the set of aggregation functions that guarantee the existence of pure Nash equilibria. AU - Feldotto, Matthias AU - Leder, Lennart AU - Skopalik, Alexander ID - 112 T2 - Proceedings of the 10th International Conference on Algorithms and Complexity (CIAC) TI - Congestion Games with Complementarities ER - TY - CONF AB - We study the computation of approximate pure Nash equilibria in Shapley value (SV) weighted congestion games, introduced in [19]. This class of games considers weighted congestion games in which Shapley values are used as an alternative (to proportional shares) for distributing the total cost of each resource among its users. We focus on the interesting subclass of such games with polynomial resource cost functions and present an algorithm that computes approximate pure Nash equilibria with a polynomial number of strategy updates. Since computing a single strategy update is hard, we apply sampling techniques which allow us to achieve polynomial running time. The algorithm builds on the algorithmic ideas of [7], however, to the best of our knowledge, this is the first algorithmic result on computation of approximate equilibria using other than proportional shares as player costs in this setting. We present a novel relation that approximates the Shapley value of a player by her proportional share and vice versa. As side results, we upper bound the approximate price of anarchy of such games and significantly improve the best known factor for computing approximate pure Nash equilibria in weighted congestion games of [7]. AU - Feldotto, Matthias AU - Gairing, Martin AU - Kotsialou, Grammateia AU - Skopalik, Alexander ID - 113 T2 - Proceedings of the 13th International Conference on Web and Internet Economics (WINE) TI - Computing Approximate Pure Nash Equilibria in Shapley Value Weighted Congestion Games ER - TY - CONF AU - Polevoy, Gleb AU - Trajanovski, Stojan AU - Grosso, Paola AU - de Laat, Cees ID - 17652 KW - flow KW - filter KW - MMSA KW - set cover KW - approximation KW - local ratio algorithm SN - 978-3-319-71150-8 T2 - Combinatorial Optimization and Applications: 11th International Conference, COCOA 2017, Shanghai, China, December 16-18, 2017, Proceedings, Part I TI - Filtering Undesirable Flows in Networks ER - TY - CONF AU - Polevoy, Gleb AU - de Weerdt, M.M. ID - 17653 KW - interaction KW - reciprocation KW - contribute KW - shared effort KW - curbing KW - convergence KW - threshold KW - Nash equilibrium KW - social welfare KW - efficiency KW - price of anarchy KW - price of stability T2 - Proceedings of the 29th Benelux Conference on Artificial Intelligence TI - Reciprocation Effort Games ER - TY - CONF AU - Polevoy, Gleb AU - de Weerdt, M.M. ID - 17654 KW - agents KW - projects KW - contribute KW - shared effort game KW - competition KW - quota KW - threshold KW - Nash equilibrium KW - social welfare KW - efficiency KW - price of anarchy KW - price of stability T2 - Proceedings of the 29th Benelux Conference on Artificial Intelligence TI - Competition between Cooperative Projects ER - TY - GEN AB - We consider a swarm of $n$ autonomous mobile robots, distributed on a 2-dimensional grid. A basic task for such a swarm is the gathering process: All robots have to gather at one (not predefined) place. A common local model for extremely simple robots is the following: The robots do not have a common compass, only have a constant viewing radius, are autonomous and indistinguishable, can move at most a constant distance in each step, cannot communicate, are oblivious and do not have flags or states. The only gathering algorithm under this robot model, with known runtime bounds, needs $\mathcal{O}(n^2)$ rounds and works in the Euclidean plane. The underlying time model for the algorithm is the fully synchronous $\mathcal{FSYNC}$ model. On the other side, in the case of the 2-dimensional grid, the only known gathering algorithms for the same time and a similar local model additionally require a constant memory, states and "flags" to communicate these states to neighbors in viewing range. They gather in time $\mathcal{O}(n)$. In this paper we contribute the (to the best of our knowledge) first gathering algorithm on the grid that works under the same simple local model as the above mentioned Euclidean plane strategy, i.e., without memory (oblivious), "flags" and states. We prove its correctness and an $\mathcal{O}(n^2)$ time bound in the fully synchronous $\mathcal{FSYNC}$ time model. This time bound matches the time bound of the best known algorithm for the Euclidean plane mentioned above. We say gathering is done if all robots are located within a $2\times 2$ square, because in $\mathcal{FSYNC}$ such configurations cannot be solved. AU - Fischer, Matthias AU - Jung, Daniel AU - Meyer auf der Heide, Friedhelm ID - 17811 T2 - arXiv:1702.03400 TI - Gathering Anonymous, Oblivious Robots on a Grid ER - TY - CONF AB - Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time.The machine requires a setup taking $s$ time units whenever it switches from processing jobs of one type to jobs of a different type.We consider the problem as an online problem where each job is only known to the scheduler as soon as it arrives and where the processing time of a job only becomes known upon its completion (non-clairvoyance).We are interested in the potential of simple ``greedy-like'' algorithms.We analyze a modification of the FIFO strategy and show its competitiveness to be $\Theta(\sqrt{n})$, which is optimal for the considered class of algorithms.For $k=2$ types it achieves a constant competitiveness.Our main insight is obtained by an analysis of the smoothed competitiveness.If processing times $p_j$ are independently perturbed to $\hat p_j = (1+X_j)p_j$, we obtain a competitiveness of $O(\sigma^{-2} \log^2 n)$ when $X_j$ is drawn from a uniform or a (truncated) normal distribution with standard deviation $\sigma$.The result proves that bad instances are fragile and ``practically'' one might expect a much better performance than given by the $\Omega(\sqrt{n})$-bound. AU - Mäcker, Alexander AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören ID - 79 T2 - Proceedings of the 15th Workshop on Approximation and Online Algorithms (WAOA) TI - Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup Times VL - 10787 ER - TY - CONF AB - Many graph problems such as maximum cut, chromatic number, hamiltonian cycle, and edge dominating set are known to be fixed-parameter tractable (FPT) when parameterized by the treewidth of the input graphs, but become W-hard with respect to the clique-width parameter. Recently, Gajarský et al. proposed a new parameter called modular-width using the notion of modular decomposition of graphs. They showed that the chromatic number problem and the partitioning into paths problem, and hence hamiltonian path and hamiltonian cycle, are FPT when parameterized by this parameter. In this paper, we study modular-width in parameterized parallel complexity and show that the weighted maximum clique problem and the maximum matching problem are fixed-parameter parallel-tractable (FPPT) when parameterized by this parameter. AU - Abu-Khzam, Faisal N. AU - Li, Shouwei AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Podlipyan, Pavel ID - 82 T2 - Proceedings of the 11th International Workshop on Frontiers in Algorithmics (FAW) TI - Modular-Width: An Auxiliary Parameter for Parameterized Parallel Complexity ER - TY - CONF AB - We consider a scheduling problem on $m$ identical processors sharing an arbitrarily divisible resource. In addition to assigning jobs to processors, the scheduler must distribute the resource among the processors (e.g., for three processors in shares of 20\%, 15\%, and 65\%) and adjust this distribution over time. Each job $j$ comes with a size $p_j \in \mathbb{R}$ and a resource requirement $r_j > 0$. Jobs do not benefit when receiving a share larger than $r_j$ of the resource. But providing them with a fraction of the resource requirement causes a linear decrease in the processing efficiency. We seek a (non-preemptive) job and resource assignment minimizing the makespan.Our main result is an efficient approximation algorithm which achieves an approximation ratio of $2 + 1/(m-2)$. It can be improved to an (asymptotic) ratio of $1 + 1/(m-1)$ if all jobs have unit size. Our algorithms also imply new results for a well-known bin packing problem with splittable items and a restricted number of allowed item parts per bin.Based upon the above solution, we also derive an approximation algorithm with similar guarantees for a setting in which we introduce so-called tasks each containing several jobs and where we are interested in the average completion time of tasks (a task is completed when all its jobs are completed). AU - Kling, Peter AU - Mäcker, Alexander AU - Riechers, Sören AU - Skopalik, Alexander ID - 59 T2 - Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - Sharing is Caring: Multiprocessor Scheduling with a Sharable Resource ER - TY - CONF AU - Feldkord, Björn AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm ID - 70 T2 - Proceedings of the 11th Annual International Conference on Combinatorial Optimization and Applications (COCOA) TI - Price Fluctuations in Online Leasing ER - TY - THES AU - Podlipyan, Pavel ID - 703 TI - Local Algorithms for the Continuous Gathering Problem ER - TY - THES AU - Riechers, Sören ID - 704 TI - Scheduling with Scarce Resources ER - TY - JOUR AU - Mäcker, Alexander AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören ID - 706 IS - 4 JF - Journal of Combinatorial Optimization TI - Cost-efficient Scheduling on Machines from the Cloud VL - 36 ER - TY - CONF AB - Bridging the gap between informal, imprecise, and vague user requirements descriptions and precise formalized specifications is the main task of requirements engineering. Techniques such as interviews or story telling are used when requirements engineers try to identify a user's needs. The requirements specification process is typically done in a dialogue between users, domain experts, and requirements engineers. In our research, we aim at automating the specification of requirements. The idea is to distinguish between untrained users and trained users, and to exploit domain knowledge learned from previous runs of our system. We let untrained users provide unstructured natural language descriptions, while we allow trained users to provide examples of behavioral descriptions. In both cases, our goal is to synthesize formal requirements models similar to statecharts. From requirements specification processes with trained users, behavioral ontologies are learned which are later used to support the requirements specification process for untrained users. Our research method is original in combining natural language processing and search-based techniques for the synthesis of requirements specifications. Our work is embedded in a larger project that aims at automating the whole software development and deployment process in envisioned future software service markets. AU - van Rooijen, Lorijn AU - Bäumer, Frederik Simon AU - Platenius, Marie Christin AU - Geierhos, Michaela AU - Hamann, Heiko AU - Engels, Gregor ID - 97 KW - Software KW - Unified modeling language KW - Requirements engineering KW - Ontologies KW - Search problems KW - Natural languages SN - 978-1-5386-3489-9 T2 - 2017 IEEE 25th International Requirements Engineering Conference Workshops (REW) TI - From User Demand to Software Service: Using Machine Learning to Automate the Requirements Specification Process ER - TY - CONF AB - We introduce the mobile server problem, inspired by current trends to move computational tasks from cloud structures to multiple devices close to the end user. An example for this are embedded systems in autonomous cars that communicate in order to coordinate their actions. Our model is a variant of the classical Page Migration Problem. Moreformally, we consider a mobile server holding a data page.The server can move in the Euclidean space (of arbitrary dimension). In every round, requests for data items from the page pop up at arbitrary points in the space. The requests are served, each at a cost of the distance from the requesting point and the server, and the mobile server may move, at a cost D times the distance traveled for some constant D . We assume a maximum distance m the server is allowed to move per round. We show that no online algorithm can achieve a competitive ratio independent of the length of the input sequence in this setting. Hence we augment the maximum movement distance of the online algorithms to ( 1 + δ) times the maximum distance of the offline solution. We provide a deterministic algorithm which is simple to describe and works for multiple variants of our problem. The algorithm achieves almost tight competitive ratios independent of the length of the input sequence. AU - Feldkord, Björn AU - Meyer auf der Heide, Friedhelm ID - 55 T2 - Proceedings of the 29th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - The Mobile Server Problem ER - TY - CONF AB - In budget games, players compete over resources with finite budgets. For every resource, a player has a specific demand and as a strategy, he chooses a subset of resources. If the total demand on a resource does not exceed its budget, the utility of each player who chose that resource equals his demand. Otherwise, the budget is shared proportionally. In the general case, pure Nash equilibria (NE) do not exist for such games. In this paper, we consider the natural classes of singleton and matroid budget games with additional constraints and show that for each, pure NE can be guaranteed. In addition, we introduce a lexicographical potential function to prove that every matroid budget game has an approximate pure NE which depends on the largest ratio between the different demands of each individual player. AU - Drees, Maximilian AU - Feldotto, Matthias AU - Riechers, Sören AU - Skopalik, Alexander ID - 66 T2 - Proceedings of the 23rd International Computing and Combinatorics Conference (COCOON) TI - Pure Nash Equilibria in Restricted Budget Games ER - TY - GEN AU - Nowack, Joshua ID - 695 TI - On-The-Fly Konstruktion zusammenhängender Straßennetze aus gegebenen Einzelteilen ER - TY - BOOK AU - Gausemeier, Jürgen AU - Bodden, Eric AU - Dressler, Falko AU - Dumitrescu, Roman AU - Meyer auf der Heide, Friedhelm AU - Scheytt, Christoph AU - Trächtler, Ansgar ID - 16444 TI - Wissenschaftsforum Intelligente Technische Systeme (WInTeSys) ER - TY - CHAP AU - Bemmann, Pascal AU - Biermeier, Felix AU - Bürmann, Jan AU - Kemper, Arne AU - Knollmann, Till AU - Knorr, Steffen AU - Kothe, Nils AU - Mäcker, Alexander AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören AU - Schaefer, Johannes Sebastian AU - Sundermeier, Jannik ID - 16461 SN - 0302-9743 T2 - Structural Information and Communication Complexity TI - Monitoring of Domain-Related Problems in Distributed Data Streams ER - TY - GEN AU - Nachtigall, Simon ID - 1073 TI - Sortieren dynamischer Daten ER - TY - GEN AU - Pukrop, Simon ID - 1074 TI - Robuste Optimierung in Congestion Games ER - TY - GEN AU - Bürmann, Jan ID - 1080 TI - Complexity of Signalling in Routing Games under Uncertainty ER - TY - GEN AU - Vijayalakshmi, Vipin Ravindran ID - 1081 TI - Bounding the Inefficiency of Equilibria in Congestion Games under Taxation ER - TY - CONF AB - Many university students struggle with motivational problems, and gamification has the potential to address these problems. However, gamification is hardly used in education, because current approaches to gamification require instructors to engage in the time-consuming preparation of their course contents for use in quizzes, mini-games and the like. Drawing on research on limited attention and present bias, we propose a "lean" approach to gamification, which relies on gamifying learning activities (rather than learning contents) and increasing their salience. In this paper, we present the app StudyNow that implements such a lean gamification approach. With this app, we aim to enable more students and instructors to benefit from the advantages of gamification. AU - Feldotto, Matthias AU - John, Thomas AU - Kundisch, Dennis AU - Hemsen, Paul AU - Klingsieck, Katrin AU - Skopalik, Alexander ID - 1094 T2 - Proceedings of the 12th International Conference on Design Science Research in Information Systems and Technology (DESRIST) TI - Making Gamification Easy for the Professor: Decoupling Game and Content with the StudyNow Mobile App ER - TY - CONF AB - Many university students struggle with motivational problems, and gamification has the potential to address these problems. However, using gamification currently is rather tedious and time-consuming for instructors because current approaches to gamification require instructors to engage in the time-consuming preparation of course contents (e.g., for quizzes or mini-games). In reply to this issue, we propose a “lean” approach to gamification, which relies on gamifying learning activities rather than learning contents. The learning activities that are gamified in the lean approach can typically be drawn from existing course syllabi (e.g., attend certain lectures, hand in assignments, read book chapters and articles). Hence, compared to existing approaches, lean gamification substantially lowers the time requirements posed on instructors for gamifying a given course. Drawing on research on limited attention and the present bias, we provide the theoretical foundation for the lean gamification approach. In addition, we present a mobile application that implements lean gamification and outline a mixed-methods study that is currently under way for evaluating whether lean gamification does indeed have the potential to increase students’ motivation. We thereby hope to allow more students and instructors to benefit from the advantages of gamification. AU - John, Thomas AU - Feldotto, Matthias AU - Hemsen, Paul AU - Klingsieck, Katrin AU - Kundisch, Dennis AU - Langendorf, Mike ID - 1095 T2 - Proceedings of the 25th European Conference on Information Systems (ECIS) TI - Towards a Lean Approach for Gamifying Education ER - TY - JOUR AB - We consider an extension of the dynamic speed scaling scheduling model introduced by Yao et al.: A set of jobs, each with a release time, deadline, and workload, has to be scheduled on a single, speed-scalable processor. Both the maximum allowed speed of the processor and the energy costs may vary continuously over time. The objective is to find a feasible schedule that minimizes the total energy costs. Theoretical algorithm design for speed scaling problems often tends to discretize problems, as our tools in the discrete realm are often better developed or understood. Using the above speed scaling variant with variable, continuous maximal processor speeds and energy prices as an example, we demonstrate that a more direct approach via tools from variational calculus can not only lead to a very concise and elegant formulation and analysis, but also avoids the “explosion of variables/constraints” that often comes with discretizing. Using well-known tools from calculus of variations, we derive combinatorial optimality characteristics for our continuous problem and provide a quite concise and simple correctness proof. AU - Antoniadis, Antonios AU - Kling, Peter AU - Ott, Sebastian AU - Riechers, Sören ID - 110 JF - Theoretical Computer Science TI - Continuous Speed Scaling with Variability: A Simple and Direct Approach ER - TY - CONF AB - To detect errors or find potential for improvement during the CAD-supported development of a complex technical system like modern industrial machines, the system’s virtual prototype can be examined in virtual reality (VR) in the context of virtual design reviews. Besides exploring the static shape of the examined system, observing the machines’ mechanics (e.g., motor-driven mechanisms) and transport routes for the material transport (e.g., via conveyor belts or chains, or rail-based transport systems) can play an equally important role in such a review. In practice it is often the case, that the relevant information about transport routes, or kinematic properties is either not consequently modeled in the CAD data or is lost during conversion processes. To significantly reduce the manual effort and costs for creating animations of the machines complex behavior with such limited input data for a design review, we present a set of algorithms to automatically determine geometrical properties of machine parts based only on their triangulated surfaces. The algorithms allow to detect the course of transport systems, the orientation of objects in 3d space, rotation axes of cylindrical objects and holes, the number of tooth of gears, as well as the tooth spacing of toothed racks. We implemented the algorithms in the VR system PADrend and applied them to animate virtual prototypes of real machines. AU - Brandt, Sascha AU - Fischer, Matthias AU - Gerges, Maria AU - Jähn, Claudius AU - Berssenbrügge, Jan ID - 16338 SN - 9780791858110 T2 - Volume 1: 37th Computers and Information in Engineering Conference TI - Automatic Derivation of Geometric Properties of Components From 3D Polygon Models VL - 1 ER - TY - CONF AB - In der CAD-unterstützten Entwicklung von technischen Systemen (Maschinen, Anlagen etc.) werden virtuelle Prototypen im Rahmen eines virtuellen Design-Reviews mit Hilfe eines VR-Systems gesamtheitlich betrachtet, um frühzeitig Fehler und Verbesserungsbedarf zu erkennen. Ein wichtiger Untersuchungsgegenstand ist dabei die Analyse von Transportwegen für den Materialtransport mittels Fließbändern, Förderketten oder schienenbasierten Transportsystemen. Diese Transportwege werden im VR-System animiert. Problematisch dabei ist, dass derartige Transportsysteme im zugrundeliegenden CAD-Modell in der Praxis oft nicht modelliert und nur exemplarisch angedeutet werden, da diese für die Konstruktion nicht relevant sind (z.B. der Fördergurt eines Förderbandes, oder die Kette einer Förderkette), oder die Informationen über den Verlauf bei der Konvertierung der Daten in das VR-System verloren gehen. Bei der Animation dieser Transportsysteme in einem VR-System muss der Transportweg also aufwändig, manuell nachgearbeitet werden. Das Ziel dieser Arbeit ist die Reduzierung des notwendigen manuellen Nachbearbeitungsaufwandes für das Design-Review durch eine automatische Berechnung der Animationspfade entlang eines Transportsystems. Es wird ein Algorithmus vorgestellt, der es ermöglicht mit nur geringem zeitlichem Benutzeraufwand den Animationspfad aus den reinen polygonalen dreidimensionalen Daten eines Transportsystems automatisch zu rekonstruieren. AU - Brandt, Sascha AU - Fischer, Matthias ID - 16339 T2 - Wissenschaftsforum Intelligente Technische Systeme (WInTeSys) 2017 TI - Automatische Ableitung der Transportwege von Transportsystemen aus dem 3D-Polygonmodell VL - 369 ER - TY - CONF AU - Fischer, Matthias AU - Jung, Daniel AU - Meyer auf der Heide, Friedhelm ED - Fernández Anta, Antonio ED - Jurdzinski, Tomasz ED - Mosteiro, Miguel A. ED - Zhang, Yanyong ID - 16347 T2 - Algorithms for Sensor Systems - 13th International Symposium on Algorithms and Experiments for Wireless Sensor Networks, {ALGOSENSORS} TI - Gathering Anonymous, Oblivious Robots on a Grid VL - 10718 ER - TY - CONF AU - Biermeier, Felix AU - Feldkord, Björn AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm ID - 16348 T2 - Proceedings of the 15th Workshop on Approximation and Online Algorithms (WAOA) TI - A Communication-Efficient Distributed Data Structure for Top-k and k-Select Queries ER - TY - CONF AU - Podlipyan, Pavel AU - Li, Shouwei AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm ID - 16349 T2 - Proceedings of the 13th International Symposium on Algorithms and Experiments for Wireless Networks (ALGOSENSORS) TI - A Continuous Strategy for Collisionless Gathering ER - TY - CONF AB - The self-organizing bio-hybrid collaboration ofrobots and natural plants allows for a variety of interestingapplications. As an example we investigate how robots can beused to control the growth and motion of a natural plant, using LEDs to provide stimuli. We follow an evolutionaryrobotics approach where task performance is determined bymonitoring the plant's reaction. First, we do initial plantexperiments with simple, predetermined controllers. Then weuse image sampling data as a model of the dynamics ofthe plant tip xy position. Second, we use this approach toevolve robot controllers in simulation. The task is to makethe plant approach three predetermined, distinct points in anxy-plane. Finally, we test the evolved controllers in real plantexperiments and find that we cross the reality gap successfully. We shortly describe how we have extended from plant tipto many points on the plant, for a model of the plant stemdynamics. Future work will extend to two-axes image samplingfor a 3-d approach. AU - Wahby, Mostafa AU - Hofstadler, Daniel Nicolas AU - Heinrich, Mary Katherine AU - Zahadat, Payam AU - Hamann, Heiko ID - 19961 SN - 9781509035342 T2 - Proc. of the 10th International Conference on Self-Adaptive and Self-Organizing Systems TI - An Evolutionary Robotics Approach to the Control of Plant Growth and Motion: Modeling Plants and Crossing the Reality Gap ER - TY - CONF AU - Heinrich, Mary Katherine AU - Wahby, Mostafa AU - Divband Soorati, Mohammad AU - Hofstadler, Daniel Nicolas AU - Zahadat, Payam AU - Ayres, Phil AU - Stoy, Kasper AU - Hamann, Heiko ID - 19968 SN - 9781509036516 T2 - Proc. of the 1st International Workshop on Self-Organising Construction (SOCO) TI - Self-Organized Construction with Continuous Building Material: Higher Flexibility Based on Braided Structures ER - TY - JOUR AU - Hamann, Heiko AU - Khaluf, Yara AU - Botev, Jean AU - Divband Soorati, Mohammad AU - Ferrante, Eliseo AU - Kosak, Oliver AU - Montanier, Jean-Marc AU - Mostaghim, Sanaz AU - Redpath, Richard AU - Timmis, Jon AU - Veenstra, Frank AU - Wahby, Mostafa AU - Zamuda, Aleš ID - 19969 JF - Frontiers in Robotics and AI SN - 2296-9144 TI - Hybrid Societies: Challenges and Perspectives in the Design of Collective Behavior in Self-organizing Systems ER - TY - CONF AU - Hamann, Heiko AU - Divband Soorati, Mohammad ID - 19979 T2 - IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016) TI - Robot Self-Assembly as Adaptive Growth Process: Collective Selection of Seed Position and Self-Organizing Tree-Structures ER - TY - JOUR AU - Dorigo, Marco AU - Hamann, Heiko AU - Valentini, Gabriele AU - Ferrante, Eliseo ID - 19983 IS - 3 JF - Journal of Autonomous Agents and Multi-Agent Systems TI - Collective Decision with 100 Kilobots: Speed vs Accuracy in Binary Discrimination Problems VL - 30 ER - TY - THES AU - Drees, Maximilian ID - 200 TI - Existence and Properties of Pure Nash Equilibria in Budget Games ER - TY - CONF AU - Hamann, Heiko AU - Valentini, Gabriele AU - Dorigo, Marco ID - 20000 SN - 0302-9743 T2 - 10th Int. Conf. on Swarm Intelligence, ANTS 2016 TI - Population Coding: A New Design Paradigm for Embodied Distributed Systems ER - TY - CONF AU - von Mammen, Sebastian AU - Hamann, Heiko AU - Heider, Michael ID - 20001 SN - 9781450344913 T2 - ACM Symposium on Virtual Reality Software and Technology (VRST) TI - Robot Gardens: An Augmented Reality Prototype for Plant-Robot Biohybrid Systems ER - TY - CONF AU - Rybář, Milan AU - Hamann, Heiko ID - 20002 SN - 9781450342063 T2 - Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2016) TI - Inspiration-Triggered Search: Towards Higher Complexities by Mimicking Creative Processes ER - TY - CONF AU - Khaluf, Yara AU - Hamann, Heiko ID - 20003 T2 - ANTS 2016 TI - On the Definition of Self-organizing Systems: Relevance of Positive/Negative Feedback and Fluctuations VL - 9882 ER - TY - CONF AU - Valentini, Gabriele AU - Brambilla, Davide AU - Hamann, Heiko AU - Dorigo, Marco ID - 20004 SN - 0302-9743 T2 - 10th Int. Conf. on Swarm Intelligence, ANTS 2016 TI - Collective Perception of Environmental Features in a Robot Swarm ER - TY - GEN AU - Leder, Lennart ID - 210 TI - Congestion Games with Mixed Objectives ER - TY - CONF AB - We present three robust overlay networks: First, we present a network that organizes the nodes into an expander and is resistant to even massive adversarial churn. Second, we develop a network based on the hypercube that maintains connectivity under adversarial DoS-attacks. For the DoS-attacks we use the notion of a Omega(log log n)-late adversary which only has access to topological information that is at least Omega(log log n) rounds old. Finally, we develop a network that combines both churn- and DoS-resistance. The networks gain their robustness through constant network reconfiguration, i.e., the topology of the networks changes constantly. Our reconguration algorithms are based on node sampling primitives for expanders and hypercubes that allow each node to sample a logarithmic number of nodes uniformly at random in O(log log n) communication rounds. These primitives are specific to overlay networks and their optimal runtime represents an exponential improvement over known techniques. Our results have a wide range of applications, for example in the area of scalable and robust peer-to-peer systems. AU - Drees, Maximilian AU - Gmyr, Robert AU - Scheideler, Christian ID - 215 T2 - Proceedings of the 28th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA) TI - Churn- and DoS-resistant Overlay Networks Based on Network Reconfiguration ER - TY - CONF AU - Polevoy, Gleb AU - de Weerdt, M.M. AU - Jonker, C.M. ID - 17655 KW - agents KW - action KW - repeated reciprocation KW - fixed KW - floating KW - network KW - Nash equilibrium KW - social welfare KW - price of anarchy KW - price of stability KW - convex combination T2 - Proceedings of the 2016 European Conference on Artificial Intelligence TI - The Game of Reciprocation Habits VL - Volume 285: ECAI 2016 ER - TY - CONF AU - Polevoy, Gleb AU - de Weerdt, Mathijs AU - Jonker, Catholijn ID - 17656 KW - agent's influence KW - behavior KW - convergence KW - perron-frobenius KW - reciprocal interaction KW - repeated reciprocation SN - 978-1-4503-4239-1 T2 - Proceedings of the 2016 International Conference on Autonomous Agents and Multiagent Systems TI - The Convergence of Reciprocation ER - TY - CONF AB - Efficiently parallelizable parameterized problems have been classified as being either in the class FPP (fixed-parameter parallelizable) or the class PNC (parameterized analog of NC), which contains FPP as a subclass. In this paper, we propose a more restrictive class of parallelizable parameterized problems called fixed-parameter parallel-tractable (FPPT). For a problem to be in FPPT, it should possess an efficient parallel algorithm not only from a theoretical standpoint but in practice as well. The primary distinction between FPPT and FPP is the parallel processor utilization, which is bounded by a polynomial function in the case of FPPT. We initiate the study of FPPT with the well-known k-vertex cover problem. In particular, we present a parallel algorithm that outperforms the best known parallel algorithm for this problem: using O(m) instead of O(n2) parallel processors, the running time improves from 4logn+O(kk) to O(k⋅log3n), where m is the number of edges, n is the number of vertices of the input graph, and k is an upper bound of the size of the sought vertex cover. We also note that a few P-complete problems fall into FPPT including the monotone circuit value problem (MCV) when the underlying graphs are bounded by a constant Euler genus. AU - Abu-Khzam, Faisal N. AU - Li, Shouwei AU - Markarian, Christine AU - Meyer auf der Heide, Friedhelm AU - Podlipyan, Pavel ID - 177 T2 - Proceedings of the 10th International Conference on Combinatorial Optimization and Applications (COCOA) TI - On the Parameterized Parallel Complexity and the Vertex Cover Problem ER - TY - GEN ED - Meyer auf der Heide, Friedhelm ID - 187 IS - 1 T2 - Transactions on Parallel Computing (TOPC) TI - Introduction to the Special Issue on SPAA 2014 ER - TY - CONF AB - We consider a scheduling problem where machines need to be rented from the cloud in order to process jobs. There are two types of machines available which can be rented for machine-type dependent prices and for arbitrary durations. However, a machine-type dependent setup time is required before a machine is available for processing. Jobs arrive online over time, have machine-type dependent sizes and have individual deadlines. The objective is to rent machines and schedule jobs so as to meet all deadlines while minimizing the rental cost. Since we observe the slack of jobs to have a fundamental influence on the competitiveness, we study the model when instances are parameterized by their (minimum) slack. An instance is called to have a slack of $\beta$ if, for all jobs, the difference between the job's release time and the latest point in time at which it needs to be started is at least $\beta$. While for $\beta series = {LNCS} AU - Mäcker, Alexander AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm AU - Riechers, Sören ID - 207 T2 - Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA) TI - Cost-efficient Scheduling on Machines from the Cloud ER - TY - CONF AB - We study a new class of games which generalizes congestion games and its bottleneck variant. We introduce congestion games with mixed objectives to model network scenarios in which players seek to optimize for latency and bandwidths alike. We characterize the existence of pure Nash equilibria (PNE) and the convergence of improvement dynamics. For games that do not possess PNE we give bounds on the approximation ratio of approximate pure Nash equilibria. AU - Feldotto, Matthias AU - Leder, Lennart AU - Skopalik, Alexander ID - 209 T2 - Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA) TI - Congestion Games with Mixed Objectives ER - TY - GEN AU - Bülling, Jonas ID - 5406 TI - Parallelisierung von Algorithmen zur IR-Luftbildanalyse von Laubholzmischbeständen zur Verifizierung der Ausbreitung von Eichenkomplexschäden ER - TY - GEN AU - Koepe, Jörn ID - 5407 TI - Price-Based Allocation Games ER - TY - GEN AU - Kutzias, Damian ID - 688 TI - Friendship Processes in Network Creation Games ER -