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 ...

Recent years, spatial data and observed data, such as digital road map, traffic route, vehicle speed, recordings events and others, are integrated and stored into the spatial temporal database systems. Various location-based services by using mobile phone are also becoming popular. In this paper, we focus on one of GIS-based scheduling applications concerning the availability of GPS technologie...

In urban areas, congestion creates a substantial variation in travel speeds during peak morning and evening hours. This research presents a new solution approach, an iterative route construction and improvement algorithm (IRCI), for the time dependent vehicle routing problem (TDVRP) with hard or soft time windows. Improvements are obtained at a route level; hence the proposed approach does not ...

Vehicle routing optimization (VRO) designs the best routes to reduce travel cost, energy consumption, and carbon emission. Due to non-deterministic polynomial-time hard (NP-hard) complexity, many VROs involved in real-world applications require too much computing effort. Shortening computing time for VRO is a great challenge for state-of-the-art spatial optimization algorithms. From a spatial-t...

In this paper, we introduce the Vehicle Routing Problem with Flexible Time Windows (VRPFlexTW), in which vehicles are allowed to deviate from customer time windows by a given tolerance. This flexibility enables savings in the operational costs of carriers, since customers may be served before and after the earliest and latest time window bounds, respectively. However, as time window deviations ...