1,737 research outputs found
Cycles in adversarial regularized learning
Regularized learning is a fundamental technique in online optimization,
machine learning and many other fields of computer science. A natural question
that arises in these settings is how regularized learning algorithms behave
when faced against each other. We study a natural formulation of this problem
by coupling regularized learning dynamics in zero-sum games. We show that the
system's behavior is Poincar\'e recurrent, implying that almost every
trajectory revisits any (arbitrarily small) neighborhood of its starting point
infinitely often. This cycling behavior is robust to the agents' choice of
regularization mechanism (each agent could be using a different regularizer),
to positive-affine transformations of the agents' utilities, and it also
persists in the case of networked competition, i.e., for zero-sum polymatrix
games.Comment: 22 pages, 4 figure
A Hierarchical Game-Theoretic Decision-Making for Cooperative Multi-Agent Systems Under the Presence of Adversarial Agents
Underlying relationships among Multi-Agent Systems (MAS) in hazardous
scenarios can be represented as Game-theoretic models. This paper proposes a
new hierarchical network-based model called Game-theoretic Utility Tree (GUT),
which decomposes high-level strategies into executable low-level actions for
cooperative MAS decisions. It combines with a new payoff measure based on agent
needs for real-time strategy games. We present an Explore game domain, where we
measure the performance of MAS achieving tasks from the perspective of
balancing the success probability and system costs. We evaluate the GUT
approach against state-of-the-art methods that greedily rely on rewards of the
composite actions. Conclusive results on extensive numerical simulations
indicate that GUT can organize more complex relationships among MAS
cooperation, helping the group achieve challenging tasks with lower costs and
higher winning rates. Furthermore, we demonstrated the applicability of the GUT
using the simulator-hardware testbed - Robotarium. The performances verified
the effectiveness of the GUT in the real robot application and validated that
the GUT could effectively organize MAS cooperation strategies, helping the
group with fewer advantages achieve higher performance.Comment: This paper is accepted by the ACM Symposium on Applied Computing
(SAC) 2023 Technical Track on Intelligent Robotics and Multi-Agent Systems
(IRMAS
Cops and Invisible Robbers: the Cost of Drunkenness
We examine a version of the Cops and Robber (CR) game in which the robber is
invisible, i.e., the cops do not know his location until they capture him.
Apparently this game (CiR) has received little attention in the CR literature.
We examine two variants: in the first the robber is adversarial (he actively
tries to avoid capture); in the second he is drunk (he performs a random walk).
Our goal in this paper is to study the invisible Cost of Drunkenness (iCOD),
which is defined as the ratio ct_i(G)/dct_i(G), with ct_i(G) and dct_i(G) being
the expected capture times in the adversarial and drunk CiR variants,
respectively. We show that these capture times are well defined, using game
theory for the adversarial case and partially observable Markov decision
processes (POMDP) for the drunk case. We give exact asymptotic values of iCOD
for several special graph families such as -regular trees, give some bounds
for grids, and provide general upper and lower bounds for general classes of
graphs. We also give an infinite family of graphs showing that iCOD can be
arbitrarily close to any value in [2,infinty). Finally, we briefly examine one
more CiR variant, in which the robber is invisible and "infinitely fast"; we
argue that this variant is significantly different from the Graph Search game,
despite several similarities between the two games
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