The multiple traveling salesman problem (MTSP) is a generalization of the famous traveling salesman problem (TSP), where more than one salesman is used in the solution. Although the MTSP is a typical kind of computationally complex combinatorial optimization problem, it can be extended to a wide variety of routing problems. This paper presents an efficient and evolutionary optimization algorith...

The vehicle routing problem with stochastic demands and customers (VRPSDC) requires finding the optimal route for a capacitated vehicle that delivers goods to a set of customers, where each customer has a fixed probability of requiring being visited and a stochastic demand. For large instances, the evaluation of the cost function is a primary bottleneck when searching for high quality solutions...

In this paper we will deal with the sequencing and routing problem of order pickers in conventional multi-parallel-aisle warehouse systems. For this NP-hard Steiner Travelling Salesman Problem exact algorithms only exist for warehouses with at most three cross aisles. We propose a new approach were the problem of routing order pickers in multiple-block warehouses is translated into a classical ...

The vehicle routing problem with stochastic demands consists in designing transportation routes of minimal expected cost to satisfy a set of customers with random demands of known probability distribution. This paper proposes a novel heuristic approach that uses randomized heuristics for the traveling salesman problem, a tour partitioning procedure, and a set-partitioning formulation to sample ...

We consider the vehicle routing problem with stochastic demands (VRPSD). We give randomized approximation algorithms achieving approximation guarantees of 1 + for split-delivery VRPSD, and 2 + for unsplit-delivery VRPSD; here  is the best approximation guarantee for the traveling salesman problem. These bounds match the best known for even the respective deterministic problems [Altinkemer, K...

one of the big concerns of big cities is facing with the increase of fossil fuel vehicles in the roads. the cars intensify greenhouse gas emission in civic centers. one approach to reduce the emission is replacing the cars by plug-in electric vehicles (pevs). in spite of reducing the emission, pevs have some adverse effect on electric distribution networks. technical challenges such as load and...

This study introduces the One-Commodity Pickup and Delivery Traveling Salesman Problem with Demand Intervals (1-PDTSP-DI), a generalization of the One Commodity Pickup and Delivery Traveling Salesman Problem (1-PDTSP). In the 1-PDTSP-DI, the vertices are required to have an inventory lying between given lower and upper bounds and initially have an inventory which does not necessarily lie betwee...