@inproceedings{66,
abstract = {{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.}},
author = {{Drees, Maximilian and Feldotto, Matthias and Riechers, Sören and Skopalik, Alexander}},
booktitle = {{Proceedings of the 23rd International Computing and Combinatorics Conference (COCOON)}},
pages = {{175----187}},
title = {{{Pure Nash Equilibria in Restricted Budget Games}}},
doi = {{10.1007/978-3-319-62389-4_15}},
year = {{2017}},
}
@misc{1073,
author = {{Nachtigall, Simon}},
publisher = {{Universität Paderborn}},
title = {{{Sortieren dynamischer Daten}}},
year = {{2017}},
}
@misc{1074,
author = {{Pukrop, Simon}},
publisher = {{Universität Paderborn}},
title = {{{Robuste Optimierung in Congestion Games}}},
year = {{2017}},
}
@misc{1080,
author = {{Bürmann, Jan}},
publisher = {{Universität Paderborn}},
title = {{{Complexity of Signalling in Routing Games under Uncertainty}}},
year = {{2017}},
}
@misc{1081,
author = {{Vijayalakshmi, Vipin Ravindran}},
publisher = {{Universität Paderborn}},
title = {{{Bounding the Inefficiency of Equilibria in Congestion Games under Taxation}}},
year = {{2017}},
}
@inproceedings{1094,
abstract = {{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.}},
author = {{Feldotto, Matthias and John, Thomas and Kundisch, Dennis and Hemsen, Paul and Klingsieck, Katrin and Skopalik, Alexander}},
booktitle = {{Proceedings of the 12th International Conference on Design Science Research in Information Systems and Technology (DESRIST)}},
pages = {{462--467}},
title = {{{Making Gamification Easy for the Professor: Decoupling Game and Content with the StudyNow Mobile App}}},
doi = {{10.1007/978-3-319-59144-5_32}},
year = {{2017}},
}
@inproceedings{1095,
abstract = {{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. }},
author = {{John, Thomas and Feldotto, Matthias and Hemsen, Paul and Klingsieck, Katrin and Kundisch, Dennis and Langendorf, Mike}},
booktitle = {{Proceedings of the 25th European Conference on Information Systems (ECIS)}},
pages = {{2970--2979}},
title = {{{Towards a Lean Approach for Gamifying Education}}},
year = {{2017}},
}
@phdthesis{200,
author = {{Drees, Maximilian}},
publisher = {{Universität Paderborn}},
title = {{{Existence and Properties of Pure Nash Equilibria in Budget Games}}},
year = {{2016}},
}
@misc{210,
author = {{Leder, Lennart}},
publisher = {{Universität Paderborn}},
title = {{{Congestion Games with Mixed Objectives}}},
year = {{2016}},
}
@inproceedings{17655,
author = {{Polevoy, Gleb and de Weerdt, M.M. and Jonker, C.M.}},
booktitle = {{Proceedings of the 2016 European Conference on Artificial Intelligence}},
keywords = {{agents, action, repeated reciprocation, fixed, floating, network, Nash equilibrium, social welfare, price of anarchy, price of stability, convex combination}},
pages = {{417--425}},
title = {{{The Game of Reciprocation Habits}}},
doi = {{10.3233/978-1-61499-672-9-417}},
volume = {{Volume 285: ECAI 2016}},
year = {{2016}},
}
@inproceedings{17656,
author = {{Polevoy, Gleb and de Weerdt, Mathijs and Jonker, Catholijn}},
booktitle = {{Proceedings of the 2016 International Conference on Autonomous Agents and Multiagent Systems}},
isbn = {{978-1-4503-4239-1}},
keywords = {{agent's influence, behavior, convergence, perron-frobenius, reciprocal interaction, repeated reciprocation}},
pages = {{1431--1432}},
publisher = {{International Foundation for Autonomous Agents and Multiagent Systems}},
title = {{{The Convergence of Reciprocation}}},
year = {{2016}},
}
@inproceedings{209,
abstract = {{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.}},
author = {{Feldotto, Matthias and Leder, Lennart and Skopalik, Alexander}},
booktitle = {{Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA)}},
pages = {{655----669}},
title = {{{Congestion Games with Mixed Objectives}}},
doi = {{10.1007/978-3-319-48749-6_47}},
year = {{2016}},
}
@misc{1082,
author = {{Handirk, Tobias}},
publisher = {{Universität Paderborn}},
title = {{{Über die Rolle von Informationen in Verkehrsnetzwerken}}},
year = {{2016}},
}
@article{159,
abstract = {{Abstract—Max-min fairness (MMF) is a widely known approachto a fair allocation of bandwidth to each of the usersin a network. This allocation can be computed by uniformlyraising the bandwidths of all users without violating capacityconstraints. We consider an extension of these allocations byraising the bandwidth with arbitrary and not necessarily uniformtime-depending velocities (allocation rates). These allocationsare used in a game-theoretic context for routing choices, whichwe formalize in progressive filling games (PFGs). We present avariety of results for equilibria in PFGs. We show that these gamespossess pure Nash and strong equilibria. While computation ingeneral is NP-hard, there are polynomial-time algorithms forprominent classes of Max-Min-Fair Games (MMFG), includingthe case when all users have the same source-destination pair.We characterize prices of anarchy and stability for pure Nashand strong equilibria in PFGs and MMFGs when players havedifferent or the same source-destination pairs. In addition, weshow that when a designer can adjust allocation rates, it is possibleto design games with optimal strong equilibria. Some initial resultson polynomial-time algorithms in this direction are also derived.}},
author = {{Harks, Tobias and Höfer, Martin and Schewior, Kevin and Skopalik, Alexander}},
journal = {{IEEE/ACM Transactions on Networking}},
number = {{4}},
pages = {{2553 -- 2562}},
publisher = {{IEEE}},
title = {{{Routing Games With Progressive Filling}}},
doi = {{10.1109/TNET.2015.2468571}},
year = {{2016}},
}
@inproceedings{149,
abstract = {{In this paper we consider a strategic variant of the online facility location problem. Given is a graph in which each node serves two roles: it is a strategic client stating requests as well as a potential location for a facility. In each time step one client states a request which induces private costs equal to the distance to the closest facility. Before serving, the clients may collectively decide to open new facilities, sharing the corresponding price. Instead of optimizing the global costs, each client acts selfishly. The prices of new facilities vary between nodes and also change over time, but are always bounded by some fixed value α. Both the requests as well as the facility prices are given by an online sequence and are not known in advance.We characterize the optimal strategies of the clients and analyze their overall performance in comparison to a centralized offline solution. If all players optimize their own competitiveness, the global performance of the system is O(√α⋅α) times worse than the offline optimum. A restriction to a natural subclass of strategies improves this result to O(α). We also show that for fixed facility costs, we can find strategies such that this bound further improves to O(√α).}},
author = {{Drees, Maximilian and Feldkord, Björn and Skopalik, Alexander}},
booktitle = {{Proceedings of the 10th Annual International Conference on Combinatorial Optimization and Applications (COCOA)}},
pages = {{593----607}},
title = {{{Strategic Online Facility Location}}},
doi = {{10.1007/978-3-319-48749-6_43}},
year = {{2016}},
}
@article{145,
abstract = {{Comparative evaluations of peer-to-peer protocols through simulations are a viable approach to judge the performance and costs of the individual protocols in large-scale networks. In order to support this work, we present the peer-to-peer system simulator PeerfactSim.KOM, which we extended over the last years. PeerfactSim.KOM comes with an extensive layer model to support various facets and protocols of peer-to-peer networking. In this article, we describe PeerfactSim.KOM and show how it can be used for detailed measurements of large-scale peer-to-peer networks. We enhanced PeerfactSim.KOM with a fine-grained analyzer concept, with exhaustive automated measurements and gnuplot generators as well as a coordination control to evaluate sets of experiment setups in parallel. Thus, by configuring all experiments and protocols only once and starting the simulator, all desired measurements are performed, analyzed, evaluated, and combined, resulting in a holistic environment for the comparative evaluation of peer-to-peer systems. An immediate comparison of different configurations and overlays under different aspects is possible directly after the execution without any manual post-processing. }},
author = {{Feldotto, Matthias and Graffi, Kalman}},
journal = {{Concurrency and Computation: Practice and Experience}},
number = {{5}},
pages = {{1655--1677}},
publisher = {{Wiley Online Library}},
title = {{{Systematic evaluation of peer-to-peer systems using PeerfactSim.KOM}}},
doi = {{10.1002/cpe.3716}},
volume = {{28}},
year = {{2016}},
}
@misc{251,
author = {{Pfannschmidt, Karlson}},
publisher = {{Universität Paderborn}},
title = {{{Solving the aggregated bandits problem}}},
year = {{2015}},
}
@article{320,
abstract = {{We consider structural and algorithmic questions related to the Nash dynamics of weighted congestion games. In weighted congestion games with linear latency functions, the existence of pure Nash equilibria is guaranteed by a potential function argument. Unfortunately, this proof of existence is inefficient and computing pure Nash equilibria in such games is a PLS-hard problem even when all players have unit weights. The situation gets worse when superlinear (e.g., quadratic) latency functions come into play; in this case, the Nash dynamics of the game may contain cycles and pure Nash equilibria may not even exist. Given these obstacles, we consider approximate pure Nash equilibria as alternative solution concepts. A ρ--approximate pure Nash equilibrium is a state of a (weighted congestion) game from which no player has any incentive to deviate in order to improve her cost by a multiplicative factor higher than ρ. Do such equilibria exist for small values of ρ? And if so, can we compute them efficiently?We provide positive answers to both questions for weighted congestion games with polynomial latency functions by exploiting an “approximation” of such games by a new class of potential games that we call Ψ-games. This allows us to show that these games have d!-approximate pure Nash equilibria, where d is the maximum degree of the latency functions. Our main technical contribution is an efficient algorithm for computing O(1)-approximate pure Nash equilibria when d is a constant. For games with linear latency functions, the approximation guarantee is 3+√5/2 + Oγ for arbitrarily small γ > 0; for latency functions with maximum degree d≥ 2, it is d2d+o(d). The running time is polynomial in the number of bits in the representation of the game and 1/γ. As a byproduct of our techniques, we also show the following interesting structural statement for weighted congestion games with polynomial latency functions of maximum degree d ≥ 2: polynomially-long sequences of best-response moves from any initial state to a dO(d2)-approximate pure Nash equilibrium exist and can be efficiently identified in such games as long as d is a constant.To the best of our knowledge, these are the first positive algorithmic results for approximate pure Nash equilibria in weighted congestion games. Our techniques significantly extend our recent work on unweighted congestion games through the use of Ψ-games. The concept of approximating nonpotential games by potential ones is interesting in itself and might have further applications.}},
author = {{Caragiannis, Ioannis and Fanelli, Angelo and Gravin, Nick and Skopalik, Alexander}},
journal = {{Transactions on Economics and Computation}},
number = {{1}},
publisher = {{ACM}},
title = {{{Approximate Pure Nash Equilibria in Weighted Congestion Games: Existence, Efficient Computation, and Structure}}},
doi = {{10.1145/2614687}},
volume = {{3}},
year = {{2015}},
}
@misc{316,
author = {{Pautz, Jannis}},
publisher = {{Universität Paderborn}},
title = {{{Budget Games with priced strategies}}},
year = {{2015}},
}
@inproceedings{271,
abstract = {{In \emph{bandwidth allocation games} (BAGs), the strategy of a player consists of various demands on different resources. The player's utility is at most the sum of these demands, provided they are fully satisfied. Every resource has a limited capacity and if it is exceeded by the total demand, it has to be split between the players. Since these games generally do not have pure Nash equilibria, we consider approximate pure Nash equilibria, in which no player can improve her utility by more than some fixed factor $\alpha$ through unilateral strategy changes. There is a threshold $\alpha_\delta$ (where $\delta$ is a parameter that limits the demand of each player on a specific resource) such that $\alpha$-approximate pure Nash equilibria always exist for $\alpha \geq \alpha_\delta$, but not for $\alpha < \alpha_\delta$. We give both upper and lower bounds on this threshold $\alpha_\delta$ and show that the corresponding decision problem is ${\sf NP}$-hard. We also show that the $\alpha$-approximate price of anarchy for BAGs is $\alpha+1$. For a restricted version of the game, where demands of players only differ slightly from each other (e.g. symmetric games), we show that approximate Nash equilibria can be reached (and thus also be computed) in polynomial time using the best-response dynamic. Finally, we show that a broader class of utility-maximization games (which includes BAGs) converges quickly towards states whose social welfare is close to the optimum.}},
author = {{Drees, Maximilian and Feldotto, Matthias and Riechers, Sören and Skopalik, Alexander}},
booktitle = {{Proceedings of the 8th International Symposium on Algorithmic Game Theory (SAGT)}},
pages = {{178--189}},
title = {{{On Existence and Properties of Approximate Pure Nash Equilibria in Bandwidth Allocation Games}}},
doi = {{10.1007/978-3-662-48433-3_14}},
year = {{2015}},
}