This article will introduce a method for locating mobile stations (MSs) in outdoor suburban non-line-of-sight (NLOS) environment. The measurements used to locate the MS are taken from three base stations and a satellite. Such a setup of measurements is named the hybrid-network-GPS system. The proposed method uses constraint nonlinear optimization to minimize the NLOS error. The problem is simpl...

We address the problem of generating a global detailed conflict-free railway schedule for a given set of train lines and frequencies and we propose a decomposition of the railway network into condensation and compensation zones in order to solve the train scheduling problem. Condensation zones lie in the proximity of main stations, where available capacity is limited and trains are therefore re...

Restructuring of European railway companies has resulted in creating new subjects within railway systems infrastructure managers (IM) on the one hand and railway operators (RO) on the other. In this paper we examine the efficiency and rank different business strategies of railway infrastructure managers using the combined AHP/DEA method. Different strategies include different number of paths al...

An extension to models for the Maximal Covering Location Problem (MCLP) is applied to the Saudi Arabian Red Crescent Society (SARCS), Riyadh City, Saudi Arabia. The purpose is to identify the optimal locations of emergency medical service (EMS) stations. This is achieved by firstly locating these stations so the maximum expected demand may be reached within a pre-specified target time. Then, se...

Such as relational databases, most graphs databases are OLTP databases (online transaction processing) of generic use and can be used to produce a wide range of solutions. That said, they shine particularly when the solution depends, first, on our understanding of how things are connected. This is more common than one may think. And in many cases it is not only how things are connected but ofte...

As we have already seen that the railway has done a lot of efforts for collision avoidance and accidents prevention. Several techniques have been developed for avoiding such hazardous loss of life and property. In this paper we have proposed an approach using latest 4G technology WiMAX (Worldwide Interoperability for Microwave Access) i.e. IEEE802.16e standards for preventing train accidents. T...