The location of railway emergency rescue spots is facing diverse scenarios including the new facilities and optimization existing layouts with limited or non-limited conditions. Generally there will be heavily redundant covering ability if all edge demands on a network are fully covered. Here, we first proposed near-full model to balance investment in facility actual coverage rate, successfully...

The hub location problem is employed for many real applications, including delivery, airline and telecommunication systems and so on. This work investigates on hierarchical hub network in which a three-level network is developed. The central hubs are considered at the first level, at the second level, hubs are assumed which are allocated to central hubs and the remaining nodes are at the third ...

Given a graph ( , ) G N E  , the Covering Salesman Problem (CSP) is to identify the minimum length tour “covering” all the nodes. More specifically, it seeks the minimum length tour visiting a subset of the nodes in N such that each node i not on the tour is within a predetermined distance di of a node on the tour. In this paper, we define and develop a generalized version of the CSP, and refe...

We introduce a new NP-complete problem asking if a “query” hypercube is (not) covered by a set of other “evidence” hypercubes. This comes down to a form of constraint reasoning asking for the satisfiability of a CNF formula where the logical atoms are inequalities over single variables, with possibly infinite variable domains. We empirically investigate the location of the phase transition regi...

Covering arrays have been studied for their applications to drug screening and software and hardware testing. In this paper, we model the problem as a constraint program. Our proposed models exploit non-binary (global) constraints, redundant modelling, channelling constraints, and symmetry breaking constraints. Our initial experiments show that with our best integrated model, we are able to eit...

Article history: Received 10 August 2012 Received in revised format 14 September 2012 Accepted September 27 2012 Available online 28 September 2012 The hub location problem involves a network of origins and destinations over which transportation takes place. There are many studies associated with finding the location of hub nodes and the allocation of demand nodes to these located hub nodes to ...

We consider the queueing maximal covering location-allocation problem QM-CLAP with an M/G/1 queueing system. We first formulate the problem as a binary quadratic programming problem and then propose a new solution procedure based on decomposition of the problem into smaller binary quadratic sub-problems. The heuristic procedure GRASP is used to solve the subproblems, as well as the entire model...

The maximal expected covering location problem (MEXCLP) and its adjusted counterpart (AMEXCLP) compute expected coverage arising only from unqueued calls, whereas the interactive use of the hypercube queueing model (HQM) considers both unqueued and queued calls in this computation. In this note we show that the three models are not strictly comparable because of the structural di=erences in the...