Locating experts via online social networks

Online social networking systems provide indirect access to a large number of people connected by multi-step chains of acquaintances, and plays an important role in the referrals for human information flow. In this paper, from a networking point of view, we study the problem of locating experts for relevant information via online social networks. We model the action of forwarding a question with random walk, adjusted by a node's awareness of the potential expertise of his immediate neighbours. Using the model we derive analytical expressions of the performance metrics of a referral session in terms of the nodes' awareness level of their neighbours and the percentage of nodes that may have answers to the posed question. We also utilize several real online social networks to study the modeled question-forwarding strategy, and find that the simulation results validate our analyses. ©2010 IEEE.published_or_final_versionThe IEEE International Conference on Communications (ICC) 2010, Cape Town, South Africa, 23-27 May 2010. In Proceedings of the IEEE ICC, 2010, p. 1-

Tragedy of the commons in online social search

Online social search (OSS) brings forth a new way to harness the Internet for answers. In this paper, we study the non-cooperation problem in OSS. We propose an analytical model that captures the behavior of OSS nodes, and, from a gaming-strategy point of view, analyze various strategies an individual node can utilize to allocate its awareness capacity. Based on this we derive the Pareto inefficiency in terms of the system cost. We also propose an incentive scheme under which the optimal state of individual nodes is also optimal for the whole system. Extensive simulations show that the strategy under our proposed incentive mechanism outperforms other strategies in terms of the system cost and the search success rate. To the best of our knowledge, this is the first study of the tragedy-of-the-commons problem in OSS. © 2011 IEEE.published_or_final_versionThe 2011 IEEE International Conference on Communications (ICC 2011), Kyoto, Japan, 5-9 June 2011. In Proceedings of ICC 2011, 2011, p. 1-

Discovering multiple resource holders in query-incentive networks

Session - Content Distribution and Peer-to-Peer NetworksIn this paper, we study the problem of discovering multiple resource holders and how to evaluate a node's satisfaction in query incentive networks. Utilizing an acyclic tree, we show that query propagation has a nature of exponential start, polynomial growth, and eventually becoming a constant. We model the query propagation as an extensive game, obtain nodes' greedy behaviors from Nash equilibrium analysis, and show the impairment of greedy behaviors via a repeated Prisoner's Dilemma. We demonstrate that cooperation enforcement is required to achieve the optimal state of resource discovery. © 2011 IEEE.published_or_final_versionThe 8th IEEE Consumer Communications and Networking Conference (CCNC 2011), Las Vegas, NV., 9-12 January 2011. In Proceedings of the 8th CCNC, 2011, p. 1000-100

Privacy exposure of online social search

Online social search brings forth a new way to harness the Internet for answers. However, the personal and often sensitive information is unwittingly exposed to others when a person looks for an expert via the underlying social network. In this paper, we propose a model in which a node's behavior of looking for an expert is adjusted by his awareness of the potential expertise of his contacts. We derive the optimal distribution of nodes' awareness level that minimizes the system's privacy exposure, and prove that it corresponds to the unique Nash equilibrium. Our analysis shows that the optimal distribution over a posed question is inversely proportional to the square root of the corresponding expertise density. ©2010 IEEE.published_or_final_versionThe IEEE Conference and Exhibition on Global Telecommunications Conference (GLOBECOM 2010), Miami, FL., 6-10 December 2010. In Proceedings of GLOBECOM 2010, 2010, p. 1-

Chemical reaction optimization for the grid scheduling problem

Grid computing collects geographically dispersed resources ranging from laptops to supercomputers to compute tasks requested by clients. Grid scheduling, i.e., assigning tasks to resources, is an NP-hard problem, and thus, metaheuristic methods are employed to find the optimal solutions. In this paper, we propose a Chemical Reaction Optimization (CRO) algorithm for the grid scheduling problem. CRO is a population-based metaheuristics mimicking the interactions between molecules in a chemical reaction. We compare the CRO approach with four generally acknowledged metaheuristics, and show that CRO performs the best. ©2010 IEEE.published_or_final_versionThe IEEE International Conference on Communications (ICC) 2010, Cape Town, South Africa, 23-27 May 2010. In Proceedings of the IEEE ICC, 2010, p. 1-

Capability and responsibility balancing in online social search

Online social search (OSS) brings forth a new way to harness the Internet for answers. In this paper, we study the balancing between OSS users' capabilities and responsibilities. Targeting a practical system design, we propose an analytical model that captures the heterogeneity of different referral sessions in OSS, and a distributed socio-aware referral strategy that can achieve the desired balance when the system reaches steady state. We show that configuring the strategy enables the system operator to control the flow of all posed questions in the system. We also discuss the implications of configuring the strategy from a gaming-strategy point of view. ©2010 IEEE.published_or_final_versionThe IEEE Conference and Exhibition on Global Telecommunications Conference (GLOBECOM 2010), Miami, FL., 6-10 December 2010. In Proceedings of GLOBECOM, 2010, p. 1-