Shahriar Minaee Jalil - Imam Khomeini International University, Qazvin, Iran
Ali khaleghi - Imam Khomeini International University, Qazvin, Iran

This paper deals with the problem of user-server assignment in online social network systems. Online social network applications such as Facebook, Twitter, or Instagram are built on an infrastructure of serversthat enables them to communicate with each other. A key factor that determines the facility of communication between the users and the servers is the Expected Transmission Time (ETT). A smart user-serverassignment can avoid the low quality links and improve the communication between nodes and also save the valuable communication resources. Unfortunately, finding the optimal assignmentturns out to be a NP-hard problem. This paper proposes the use of aheuristic algorithm named Centralized Simulated Annealing (CSA) to get a good near optimum solution for this problem. Simulation results of this investigation show that using a relatively small number of iterations, this approach achieves a very good performance improvement. On the other hand, the average number of iterations needed to achieve the nearoptimalsolution, will be slightly increased when the number of users in the network increase.

Online social networks,Client-server assignment,Centralized simulated,Annealing algorithm,