%0 Journal Article
%T Multi-Objective Genetic Algorithm for Task Assignment on Heterogeneous Nodes
%A Carolina Blanch Perez del Notario
%A Rogier Baert
%A Maja D'Hondt
%J International Journal of Digital Multimedia Broadcasting
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/716780
%X Task assignment in grid computing, where both processing and bandwidth constraints at multiple heterogeneous devices need to be considered, is a challenging problem. Moreover, targeting the optimization of multiple objectives makes it even more challenging. This paper presents a task assignment strategy based on genetic algorithms in which multiple and conflicting objectives are simultaneously optimized. Specifically, we maximize task execution quality while minimizing energy and bandwidth consumption. Moreover, in our video processing scenario; we consider transcoding to lower spatial/temporal resolutions to tradeoff between video quality; processing, and bandwidth demands. The task execution quality is then determined by the number of successfully processed streams and the spatial-temporal resolution at which they are processed. The results show that the proposed algorithm offers a range of Pareto optimal solutions that outperforms all other reference strategies. 1. Introduction Nowadays multimedia applications such as multicamera surveillance or multipoint videoconferencing, are increasingly demanding both in processing power, and bandwidth requirements. In addition, there is a tendency towards thin client applications where the processing capacities of the client device are reduced and the tasks are migrated to more powerful devices in the network. In this respect, grid computing can integrate and make use of these heterogeneous computing resources which are connected through networks, overcoming the limited processing capabilities at a clientĄ¯s device. In the context of distributed media processing we can think of scenarios such as video control rooms where multiple video streams are processed and simultaneously displayed. One way to downscale the processing and bandwidth requirements at the displaying device is by transcoding the video streams at the servers to lower temporal or spatial resolutions. This is done, however, at the cost of a degraded perceived video quality and an increased processing cost at the server. Therefore, in grid computing we may need to optimize and trade off multiple objectives, targeting for instance quality maximization of the stream execution and minimization of the energy consumption on the client/servers simultaneously. In this respect, implementing a suitable strategy for task assignment/scheduling becomes crucial for achieving a good performance in grid computing. This subject has been thoroughly studied in literature, and various heuristic approaches have been widely used for scheduling. In particular, Genetic
%U http://www.hindawi.com/journals/ijdmb/2012/716780/