Coordinating randomized policies for increasing security in multiagent systems

Praveen Paruchuri, Milind Tambe, Fernando Ordóñez, Sarit Kraus

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


Despite significant recent advances in decision theoretic frameworks for reasoning about multiagent teams, little attention has been paid to applying such frameworks in adversarial domains, where the agent team may face security threats from other agents. This paper focuses on domains where such threats are caused by unseen adversaries whose actions or payoffs are unknown. In such domains, action randomization is recognized as a key technique to deteriorate an adversary's capability to predict and exploit an agent/agent team's actions. Unfortunately, there are two key challenges in such randomization. First, randomization can reduce the expected reward (quality) of the agent team's plans, and thus we must provide some guarantees on such rewards. Second, randomization results in miscoordination in teams. While communication within an agent team can help in alleviating the miscoordination problem, communication is unavailable in many real domains or sometimes scarcely available. To address these challenges, this paper provides the following contributions. First, we recall the Multiagent Constrained MDP (MCMDP) framework that enables policy generation for a team of agents where each agent may have a limited or no(communication) resource. Second, since randomized policies generated directly for MCMDPs lead to miscoordination, we introduce a transformation algorithm that converts the MCMDP into a transformed MCMDP incorporating explicit communication and no communication actions. Third, we show that incorporating randomization results in a non-linear program and the unavailability/limited availability of communication results in addition of non-convex constraints to the non-linear program. Finally, we experimentally illustrate the benefits of our work.

Original languageEnglish
Title of host publicationSafety and Security in Multiagent Systems - Research Results from 2004-2006
EditorsMike Barley, Haralambos Mouratidis, Amy Unruh, Diana Spears, Paul Scerri, Fabio Massacci
Number of pages17
StatePublished - 2009

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4324 LNAI
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


  • Decision Theory
  • Multiagent Systems
  • Randomized Policies
  • Security


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