In hub-and-spoke systems, due to the changes in input parameters affecting system over time, transportation providers should make right and timely decisions about hub facilities. For this reason, multi-period location problems are especially important. This paper presents a comprehensive review of from 1990 up most recent published studies. First, we study developed models based on some charact...

In this paper, we extend the concepts of demand data aggregation error to location problems involving coverage. These errors, which arise flora losses in locational information, may lead to suboptimal location patterns. They are potentially more significant in covering problems than in p-median problernsIbecause the distance metric is binary in covering problems. We examine the Hillsirtan and R...

Two different relaxed versions of Gummelt’s aperiodic cluster covering rules are considered. These relaxed covering rules produce certain random tiling type structures, which are precisely characterized, along with their relationships to various other random tiling ensembles. One variant of the relaxed covering rules allows for a natural realization in terms of a vertex cluster. It is shown wit...

We performed a large-scale mapping observation toward the W33 complex and its surroundings, covering an area of $1.3^\circ \times 1.0^\circ$ , in $^{12}$CO (1-0), $^{13}$CO C$^{18}$O (1-0) lines from Purple Mountain Observatory (PMO). found new hub--filament system ranging 30 to 38.5 \kms located at complex. Three supercritical filaments are directly converging into central hub W33. Velocity gr...

The paper aims to study a multi-period maximal covering location problem with the configuration of different types facilities, as an extension classical (MCLP). proposed model can have applications such locating disaster relief hospitals, and chain supermarkets. facilities are supposed be comprised various units, called modules. modules sizes transfer between during planning horizon according d...

We consider definably compact groups in an o-minimal expansion of a real closed field. It is known that to each such group G is associated a natural exact sequence 1→ G00 → G → G/G00 → 1 where G00 is the “infinitesimal subgroup” of G and G/G00 is a compact real Lie group. We show that given a connected open subset U of G/G00 there is a canonical isomorphism between the fundamental group of U an...