Mohammed Benmubarak

Mobile WiMAX is a broadband technology that is capable of delivering triple play services (voice, data, and video). However, mobility in WiMAX system is still an issue when the mobile station (MS) moves and be handovered between base stations (BSs). This issue can cause unnecessary neighboring BS scanning and association, handover delay, and MAC overhead which may affect real-time applications. In this paper, the MS movement direction prediction (MMDP) based MS scanning to overcome the mobile WiMAX handover issues is presented. In this scheme, only potential BS candidates will be chosen for scanning purpose. Hence, the MS scanning process reputation will be reduced with these shortlisted BS candidates instead of scanning all neighbors BSs. Simulation results show that the proposed scheme reduces total scanning delay and scanning interval duration by 25% and 50% respectively.

Grid computing technology is a new field which focuses on large-scale resource sharing. The grid concept is coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations (VO). In this dynamic and geographically dispersed setting, information services are regarded as a vital component of the grid infrastructure. Grid Information Services (GIS) address the challenging problems of the discovery and ongoing monitoring of the existence and characteristics of resources, services, computations and other entities of value to the grid. The growing number of grid services available within an organization raises a new and challenging search problem: locating desired grid services. This paper proposes a search engine for grid services with improved the system efficiency by using a multi agent system (MAS)-based system for crawling