A Simulation Model for Volunteer Computing Micro-Blogging Services

Micro-blogging services (MBSs) have become increasingly popular during recent decades but most have a poor reputation in terms of privacy of the user data. Volunteer computing enables the implementation of decentralized systems based on heterogeneous resources that are donated by volunteers. However, volunteer computing is characterized by the unreliability of the resources: users are under no obligation to remain online. In this context, we define the problem of designing a directory service policy for a distributed volunteer computing MBS (DVCMBS). This service relies on repositories donated by volunteers. It is managed by a centralized directory service, which stores replicas of the blogs of other users to ensure their online availability and allocates blog replicas to online repositories in order to maximize the availability of all blogs. Likewise, efficiency is essential. We describe a simulation model of a DVCMBS, which includes a parameterized directory service policy. Preliminary numerical results are discussed.