Improving Selfish Routing for Risk-Averse Players

  • Dimitris Fotakis
  • Dimitris Kalimeris
  • Thanasis Lianeas
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9470)

Abstract

We investigate how and to which extent one can exploit risk-aversion and modify the perceived cost of the players in selfish routing so that the Price of Anarchy (\(\mathrm {PoA}\)) is improved. We introduce small random perturbations to the edge latencies so that the expected latency does not change, but the perceived cost of the players increases due to risk-aversion. We adopt the model of \(\gamma \)-modifiable routing games, a variant of routing games with restricted tolls. We prove that computing the best \(\gamma \)-enforceable flow is \(\mathrm {NP}\)-hard for parallel-link networks with affine latencies and two classes of heterogeneous risk-averse players. On the positive side, we show that for parallel-link networks with heterogeneous players and for series-parallel networks with homogeneous players, there exists a nicely structured \(\gamma \)-enforceable flow whose \(\mathrm {PoA}\) improves fast as \(\gamma \) increases. We show that the complexity of computing such a \(\gamma \)-enforceable flow is determined by the complexity of computing a Nash flow of the original game. Moreover, we prove that the \(\mathrm {PoA}\) of this flow is best possible in the worst-case, in the sense that there are instances where (i) the best \(\gamma \)-enforceable flow has the same \(\mathrm {PoA}\), and (ii) considering more flexible modifications does not lead to any further improvement.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Open Access This chapter is distributed under the terms of the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Authors and Affiliations

  • Dimitris Fotakis
    • 1
  • Dimitris Kalimeris
    • 2
  • Thanasis Lianeas
    • 3
  1. 1.School of Electrical and Computer EngineeringNational Technical University of AthensAthensGreece
  2. 2.Department of Informatics and TelecommunicationsNational and Kapodistrian University of AthensAthensGreece
  3. 3.Department of Electrical and Computer EngineeringUniversity of Texas at AustinAustinUSA

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