In Beardwood et al. [3], the authors prove that for any bounded uniform i.i.d. random variables {X i : 1 < i < oo} with values in R 2, the length of the shortest tour through {X~ ..... X,} is asymptotic to a constant times ~ with probability one (the same being true in expectation). In fact, this result is valid for any uniform i.i.d. random variables with compact support of measure one in R a,...

in recent years, reducing emissions has become an important issue. besides reducing the economic costs, reducing the fuel consumption decreases emissions, pollutant impact and increases society health as well. green vehicle routing problem are a major key to reduce hazardous effects of transportation such as air pollution, greenhouse gas (ghg) emissions, noise and the like. generally, the amoun...

This paper is a survey of location-routing: a relatively new branch of locational analysis that takes into account vehicle routing aspects. We propose a classification scheme and look at a number of problem variants. Both exact and heuristic algorithms are investigated. Finally, some suggestions for future research are presented. 2006 Elsevier B.V. All rights reserved.

this paper presents a new mathematical model for a hybrid flow shop scheduling problem with multiprocessor tasks in which sequence dependent set up times and preemption are considered. the objective is to minimize the weighted sum of makespan and maximum tardiness. three meta-heuristic methods based on genetic algorithm (ga), imperialist competitive algorithm (ica) and a hybrid approach of ga a...

Appropriate vehicle routing is critical for collecting municipal solid waste (MSW) efficiently. Conventional empirical routing is not easily altered in response to rapidly changing waste management plans and generation. An enhanced model is proposed herein to solve a MSW collection routing problem involving a homogenous fleet. A minimum cost flow method is applied to pre-process the original co...

In this paper we propose a hybrid approach for solving vehicle routing problems. The main idea is to combine an Ant System (AS) with a problem specific constructive heuristic, namely the well known Savings algorithm. This differs from previous approaches, where the subordinate heuristic was the Nearest Neighbor algorithm initially proposed for the TSP. We compare our approach with some other cl...

Centralizing and using proper transportation facilities cut down costs and traffic. Hub facilities concentrate on flows to cause economic advantage of scale and multimodal transportation helps use the advantage of another transporter. A distinctive feature of this paper is proposing a new mathematical formulation for a three-stage p-hub location routing problem with simultaneous pick-ups and de...

One of the new emerging application strategies for optimization is the hybridization of existing metaheuristics. The research combines the unique paradigms of solution space sampling of SOMA and memory retention capabilities of Scatter Search for the task of capacitated vehicle routing problem. The new hybrid heuristic is tested on the Taillard sets and obtains good results.

This work involves a heuristic for solving vehicle routing problems with time windows (VRPTW) general compatibility-matching between customer/patient and server/caretaker constraints to capture the nature of systems such as caretakers’ home visiting or healthcare (HHC) systems. Since any variation VRPTW is more complicated than regular VRP, specific, custom-made needed solve problem. The propos...