The location information of users can be replicated at various databases in a hierarchy to improve the efficiency of call lookups at the expense of increase in update and storage cost. In this paper, we systematically investigate this problem and propose two solutions. The first solution has optimal lookup and update cost, but the execution time could be exponential to the number of databases. ...

Recent work on the location of perinatal facilities in the municipality of Rio de Janeiro resulted in the development of an uncapacitated, three-level hierarchical model. An important issue that arose during the course of the research was the need to include some form of capacity constraints into the model, especially in the higher, resource intensive level of the hierarchy. This need was felt ...

A 2-level hierarchical extension of the maximal covering location problem is considered and an e0ective method for its solution developed. A combined Lagrangean–surrogate (L–S) relaxation is de6ned which reduces to a 0–1 knapsack problem. Tests were carried out using a subgradient-based heuristic incorporating the L–S relaxation, with the resulting knapsack problems being solved both with and w...

Hierarchical multimodal hub location problem is a cost-minimizing hub covering problem where two types of hubs and hub links, accounting for ground and air transportation, are to be established, while ensuring time-definite deliveries. We propose a mixed-integer programming formulation and perform a comprehensive sensitivity analysis on the Turkish network. We show that the locations of airport...

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA becomes increasingly popular. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the Location-based Service (LBS) that exploits the spatial information of moving...

We consider the problem of analyzing people’s mobility and movement patterns from their location history, gathered by mobile devices. Human mobility traces can be extremely complex and unpredictable, by nature, which makes it hard to construct accurate models of mobility behavior. In this work, we present a novel high-level strategy for mobility data analysis based on Hierarchical Dirichlet pro...

1 – Introduction: In transportation, decision-making phase has an essential role in the planning context. The actions of planners have to be efficient and dynamic to generate the best management of the resources and consequently maximize benefits. Recently, the intervening factors became more complex and related to political, economical and social interests, which have to be considered in the f...

This document describes an architecture for a global, scalable, resilient, and administratively distributed system for mapping geographic location information to URLs, using the Location-to-Service Translation (LoST) protocol. The architecture generalizes well-known approaches found in hierarchical lookup systems such as DNS.

Location-based routing protocols are stateless since they rely on position information in forwarding decisions. However, their efficiency depends on performance of location services which provide the position information of the desired destination node. Several location service schemes have been proposed, but the most promising among them, hierarchical hashing-based protocols, rely on intuitive...

IP based wireless mobile networks are of great importance now-a-days to users on the move. To provide connectivity to mobile users with same IP address despite of their change in location or point of attachment, the location information of mobile users must be kept up to date. Managing location information of such users basically needs information to be exchanged between different network entit...