Sharing in Networks of Strategic Agents

In social, economic and engineering networks, connected agents need to cooperate by repeatedly sharing information and/or goods. Typically, sharing is costly and there are no immediate benefits for agents who share. Hence, agents who strategically aim to maximize their own individual utilities will "free-ride" because they lack incentives to cooperate/share, thereby leading to inefficient operation or even collapse of networks. To incentivize the strategic agents to cooperate with each other, we design distributed rating protocols which exploit the ongoing nature of the agents' interactions to assign ratings and through them, determine future rewards and punishments: agents that have behaved as directed enjoy high ratings-and hence greater future access to the information/goods of others; agents that have not behaved as directed enjoy low ratings-and hence less future access to the information/goods of others. Unlike existing rating protocols, the proposed protocol operates in a distributed manner and takes into consideration the underlying interconnectivity of agents as well as their heterogeneity. We prove that in many networks, the price of anarchy (PoA) obtained by adopting the proposed rating protocols is 1, that is, the optimal social welfare is attained. In networks where PoA is larger than 1, we show that the proposed rating protocol significantly outperforms existing incentive mechanisms. Last but not least, the proposed rating protocols can also operate efficiently in dynamic networks, where new agents enter the network over time.