objectives: to locate the road emergency stations in fars province based on using spatial multi-criteria decision making (delphi method).    methods: in this study, the criteria affecting the location of road emergency stations have been identified through delphi method and their importance was determined using analytical hierarchical process (ahp). with regard to the importance of the criteria...

In this paper, we give the rst constant-approximations for a number of layered network design problems. We begin by modeling hierarchical caching, where caches are placed in layers and each layer satis es a xed percentage of the demand (bounded miss rates). We present a constant approximation to the minimum total cost of placing the caches and routing demand through the layers. We extend this m...

In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models that are used...