Game Theory and Applications



Principal investigator

Applications and Areas of Interest

Highlighted Projects

·         Rating Systems and the Strategic Provision of Services Modern economies offer a great variety of goods and also a great variety of services. For services especially, a central question is "quality", which depends not only on the ability, trustworthiness, capability, resiliency etc. of the agent/institution/entity providing the service, but also on the effort exerted -- some or all of which may not be observable. Ensuring efficiency and resiliency in such settings thus requires treating both incomplete information about agents (adverse selection) and strategic behavior by agents (moral hazard). My recent work develops new theories for understanding and manipulating behavior in such settings and builds new mechanisms to implement these theories. Chief among these mechanisms are rating systems. A rating system consists of a rating scheme and recommended behaviors for agents that depend on the current ratings of the provider and recipient. The basic ideas are first that recipients with high ratings should be rewarded for past good behavior (by receiving good service from other agents or high payments for its services) while recipients with low ratings should be punished for past bad behavior (by receiving bad service or low payments for its services) and second that providers should provide good service (rewards) to recipients with high ratings and bad service (punishment) to recipients with low ratings. It is crucial that providers who do not give both rewards and punishments will in turn be punished with lower ratings (and hence receive bad service in the future). Rating updates are determined on the basis of reports or direct monitoring. The optimal design of a rating scheme needs to consider the reporting and monitoring methods, their accuracy, and whether the updating is performed in a centralized or distributed manner. All reporting and monitoring schemes are subject to errors, so that agents whose behavior has been in accordance to the recommendations will sometimes receive negative reports and hence receive "undeserved" future punishments; dealing with these errors presents a difficult and subtle problem. Moreover, systems will be needed for different communities and environments; e.g., if heterogeneous agents interact over a network, the rating system and its implementation need to take into consideration both the heterogeneity of agents and their connectivity. Despite these difficulties, I construct rating systems for many different environments (representing interactions of different types of agents/entities and operating in different settings) that are efficient and robust. Among the surprising results that emerge is that the optimal rating systems can be very simple, that leniency may be more effective than harshness, and that collective ratings (i.e. in which agents are rated in groups) may be more effective than individual ratings.



Activities

·         Prof. van der Schaar directs UCLA Center on Engineering Economics Learning and Networks -- (Visit the center's website!)


Highlighted Publications (For a complete list, please click here.)

  • S. Zhang and M. van der Schaar, "From Acquaintances to Friends: Homophily and Learning in Networks," Submitted, 2016. [Link]

  • Y. Song and M. van der Schaar, "Dynamic Network Formation with Foresighted Agents," Submitted, 2016. [Link]

  • S. Zhang and M. van der Schaar, " Reputational Learning and Network Dynamics," Submitted, 2016. [Link]

  • Y. Song and M. van der Schaar, "Dynamic Network Formation with Foresighted Agents," Submitted, 2016. [Link]

  • M. van der Schaar, Y. Xiao, W. R. Zame, "Endogenous Matching in a Dynamic Assignment Model with Adverse Selection and Moral Hazard," Submitted, 2016. [Link]

  • K. Ahuja, M. van der Schaar, "Repeated Matching Mechanism Design with Moral Hazard and Adverse Selection," Submitted, 2016. [Link]

  • K. Ahuja, M. van der Schaar and W. R. Zame, "A Theory of Individualism, Collectivism and Economic Outcomes," Submitted, 2016. [Link]

  • Y. Song and M. van der Schaar, "Dynamic Network Formation with Incomplete Information," Economic Theory, vol. 59, no. 2, pp. 301-331, 2015. [Link]

  • J. Park and M. van der Schaar, "The Theory of Intervention Games for Resource Sharing in Wireless Communications," IEEE J. Sel. Areas Commun., vol. 30, no. 1, pp. 165-175, Jan. 2012. [Link] [Click here for more about the intervention framework]

  • J. Park and M. van der Schaar, "Cognitive MAC Protocols Using Memory for Distributed Spectrum Sharing under Limited Spectrum Sensing," IEEE Trans. Commun., vol. 59, no. 9, pp. 2627-2637, Sep. 2011. [Link]

  • J. Park and M. van der Schaar, "Adaptive MAC Protocols Using Memory for Networks with Critical Traffic," IEEE Trans. Commun., IEEE Trans. Signal Processing, vol. 59, no.3, pp. 1269-1279, Mar. 2011. [Link]

  • J. Park and M. van der Schaar, "Medium Access Control Protocols," IEEE/ACM Trans. Networking, vol. 18, no. 6, pp. 1921-1934, Dec. 2010. [Link]

  • J. Park and M. van der Schaar, "A Game Theoretic Analysis of Incentives in Content Production and Sharing over Peer-to-Peer Networks," IEEE J. Sel. Topics Signal Process., vol. 4, no. 4, pp. 704-717, Aug. 2010. [Link]

  • J. Park and M. van der Schaar, "Stackelberg Contention Games in Multi-User Networks," EURASIP Journal on Advances in Signal Process., Special issue on Game Theory in Signal Processing and Communications, vol. 2009, Article ID 305978, 15 pages, Jan. 2009. [Link]

  • M. van der Schaar, Y. Xiao, W. Zame, "Efficient Outcomes in Repeated Games with Limited Monitoring," Economic Theory, vol. 60, no. 1, pp. 1-34, 2015 - Lead article. [Link]

  • Y. Xiao, W. R. Zame and M. van der Schaar, "Technology Choices and Pricing Policies in Public and Private Wireless Networks," IEEE Transactions on Wireless Communications,vol. 13, no. 12, Oct. 2014. [Link]

  • W. Zame, J. Xu and M. van der Schaar, "Cooperative Multi-Agent Learning and Coordination for Cognitive Radio Networks," IEEE J. Sel. Areas Commun. - Special issue on Cognitive Radio Series, vol. 32, no. 3, pp. 464-477, Mar. 2014. [Link]

  • M. van der Schaar, J. Xu and W. Zame, "Efficient Online Exchange via Fiat Money," Economic Theory, vol. 54, no. 2, pp. 211-248, Oct. 2013. [Link]

  • W. Zame, J. Xu and M. van der Schaar, "Winning the Lottery: Learning Perfect Coordination with Minimal Feedback," in IEEE J. Sel. Topics in Signal Process., vol. 7, no. 5, pp. 846-857, Oct. 2013. [Link]

  • L. Canzian, Y. Xiao, W. Zame, M. Zorzi, and M. van der Schaar, "Intervention with Complete and Incomplete Information: Application to Flow Control," in IEEE Trans. Commun., vol. 61, no. 8, pp. 3206-3218, Aug. 2013. [Link]

  • L. Canzian, Y. Xiao, W. Zame, M. Zorzi, and M. van der Schaar, "Intervention with Private Information, Imperfect Monitoring and Costly Communication," in IEEE Trans. Commun., vol. 61, no. 8, pp. 3192-3205, Aug. 2013. [Link]

  • W. Zame, J. Xu , and M. van der Schaar, "Learning Perfect Coordination with Minimal Feedback in Wireless Multi-Access Communications," IEEE Globecom 2013. [Link]

  • Y. Zhang and M. van der Schaar, "Structure-Aware Stochastic Storage Management In Smart Grids," IEEE Journal of Selected Topics in Signal Processing, Special Issue on Signal Processing in Smart Electric Power Grid, vol. 8, no. 6, pp. 1098-1110, 2014. [Link]

  • Y. Zhang and M. van der Schaar, "Collective Ratings for Online Communities with Strategic Users," IEEE Transactions on Signal Processing, vol. 62, no. 12, pp. 3069-3083, June 2014. [Link]

  • Y. Zhang, J. Park, M. van der Schaar, “Rating Protocols for Online Communities", ACM Transactions on Economics and Computation, vol. 2, no. 1, March 2014. [Link]

  • Y. Zhang and M. van der Schaar, "Robust Reputation Protocol Design for Online Communities: A Stochastic Stability Analysis," in IEEE J. of Sel. Topics in Signal Process., vol. 7, no. 5, pp. 907-920, Oct. 2013. [Link]

  • Y. Zhang and M. van der Schaar, "Strategic Networks: Information Dissemination and Link Formation Among Self-interested Agents," in IEEE J. Sel. Areas Commun. - Special issue on Network Science, vol. 31, no. 6, pp. 1115-1123, June 2013. [Link]

  • Y. Zhang and M. van der Schaar, "Information Production and Link Formation in Social Computing Systems,” in IEEE J. Sel. Areas Commun. – Special issue on Economics of Communication Networks and Systems, vol. 30, no. 10, pp. 2136-2145, Dec. 2012. [Link]