Understanding collaboration in volunteer computing systems

Volunteer computing is a paradigm in which devices participating in a distributed environment share part of their resources to help others perform their activities. The effectiveness of this computing paradigm depends on the collaboration attitude adopted by the participating devices. Unfortunately for software designers it is not clear how to contribute with local resources to the shared environment without compromising resources that could then be required by the contributors. Therefore, many designers adopt a conservative position when defining the collaboration strategy to be embedded in volunteer computing applications. This position produces an underutilization of the devices’ local resources and reduces the effectiveness of these solutions. This article presents a study that helps designers understand the impact of adopting a particular collaboration attitude to contribute with local resources to the distributed shared environment. The study considers five collaboration strategies, which are analyzed in computing environments with both, abundance and scarcity of resources. The obtained results indicate that collaboration strategies based on effort-based incentives work better than those using contribution-based incentives. These results also show that the use of effort-based incentives does not jeopardize the availability of local resources for the local needs.Peer ReviewedPostprint (published version

Strategies assessment for resource sharing networks and ad hoc systems

Traditionally, the formal modelling of systems has been done by using mathematical expression. Actually the current growing capacity of computers provides new tools to support the process of decision making in various disciplines and areas. Nowadays, computer simulation has become an essential part of system modelling. By definition a computer simulation is an attempt to model almost all the imaginable real-life or hypothetical situation on a computer so that it can be studied to see how the system works. It is a tool to virtually investigate the behaviour of the system under study. This is exactly the aim of this master thesis, examining the conduct of the system that is wanted to study using data mining methods. In essence, that system is a distributed network with resource sharing, implanted in order to solve the insufficiency of CPU resources due to the constant increasing demand. The simulation tool is capable of running various cooperation games, strategies and topologies in a fully distributed environment in order to know what the relationship between these elements is. Furthermore, the procedures used to handle the resultant information are data mining algorithms which combine tools from statistics and artificial intelligence with database management. Then, the first part focuses on the study of the simulator tool; the parameters used and output results. The second task is to investigate the data mining methods and tools used to the implementation. The next objective is to adapt the simulator results to the analysis tools and execute them. And finally analyze the results in other to check the effectiveness to see the behaviour of the system