Location-based services (LBS) depend on data gathered from mobile and ubiquitous devices and provide services like getting the appropriate location of a mobile user presented in physical and logical maps. The main operations of location management in LBS are update and search methods. Some studies to improve these were presented by using optimal sequential paging, location area scheme and hiera...

in this study, a hierarchical hub location problem by considering different modes of transportation and maximum allowed delay is investigated. this study is done on iran’s express postal service with 2 days maximum delay in delivery considering ground and airport hubs. the problem is of the type of location and single allocation for collection, transfer and distribution of the shipments. all th...