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Lab Report, 2012-01

I. Minis, K. Mamasis, V. Zeimpekis

Real-Time Management of Vehicle Breakdowns in Urban Freight Distribution, Accepted for publication in Journal of Heuristics, 2012

This paper considers a problem in which an unexpected event immobilises a vehicle of a distribution fleet permanently, and the remaining vehicles are rerouted to serve some of the clients of the failed vehicle. We model this case as a variation of the Team Orienteering Problem (TOP), constraining all vehicle routes to an upper time, or distance, limit, and taking into account the limited capacity of the fleet vehicles. The problem requires an effective solution in almost real time. We propose a new heuristic to provide efficient solutions within this strict computational time constraint. To test the quality of the heuristic, we have developed and validated a Genetic Algorithm (GA) that obtains high quality (but computationally expensive) solutions. The solutions of the heuristic compare favorably to those obtained by the GA. The latter has also been tested successfully in a real-time fleet management system.

Post date: Tuesday, January 24, 2012 - 09:41
Lab Report, 2011-09

A. Tatarakis, I. Minis

Stochastic Single Vehicle Routing Problem with Delivery and Pick Up and a Predefined Custoer Sequence, European Journal of Operation Research, vol. 213, 2011, 37-51

In this paper we study the routing of a single vehicle that delivers products and picks up items with sto- 21 chastic demand. The vehicle follows a predefined customer sequence and is allowed to return to the 22 depot for loading/unloading as needed. A suitable dynamic programming algorithm is proposed to deter- 23 mine the minimum expected routing cost. Furthermore, the optimal routing policy to be followed by the 24 vehicle’s driver is derived by proposing an appropriate theorem. The efficiency of the algorithm is studied 25 by solving large problem sets.

Post date: Tuesday, January 24, 2012 - 09:39
Lab Report, 2011-08

Th. Athanasopoulos, I. Minis

Multi-Period Routing in Hybrid Courier Operation, Chapter in Book, I. Minis, V. Zeimpekis, G. Dounias, N. Ampazis (Eds.), Supply Chain Optimization, Design & Management: Advances & Intelligent Methods, IGI Global Publications, Chapter 11, 232 – 251, 2011.

Appointment-based logistics systems, such as special courier services, or repair / maintenance services, face ever increasing competitive pressures for efficiency and on-time performance. For example, in addition to typical (core) operations, courier service providers lately deal with micrologistics activities, such as bulk product deliveries. The promise dates of such deliveries have some flexibility within a pre-specified service level. In this hybrid environment, bulk deliveries are typically planned on an ad hoc basis, without taking explicitly into account the workload for core operations, a practice that may lead to inefficiencies. This chapter proposes a new method to perform assignment of service requests (calls) with some flexibility taking into account expected routes in a multi-period horizon. The problem is solved on a rolling horizon basis in order to address the dynamics of arriving calls. The method is tested through several theoretical examples, as well as in an extensive industrial case, and appears to be superior to current methods used in practice.

Post date: Tuesday, January 24, 2012 - 09:37
Lab Report, 2011-07

I. Minis, V. Zeimpekis, G. Dounias, N. Ampazis, (Eds,)

Supply Chain Optimazation, Design and Management: Advances and Intelligent Methods, Book, IGI Global Plublishing (Former Idea), 320pages, 2011

This edited volume will focus on the contribution of Computational Intelligence to Supply Chain Management. Computational Intelligence (CI) is a term corresponding to a new generation of algorithmic methodologies in artificial intelligence, which combines elements of learning, adaptation, evolution and approximate (fuzzy) reasoning to create programs that -in a way- can be considered intelligent. The proposed edited volume will present CI methods addressing topics in the entire spectrum of the supply chain i.e. from forecasting, planning for production and distribution to actual implementation, including production and inventory control, warehouse management, management of distribution channels, and transportation. Emphasis will be given to those CI methods and techniques that provide effective solutions to complex supply chain problems, exhibiting superior performance with respect to other methods of operations research. The edited volume will also include integrated case studies that describe the solution to actual problems of high complexity.

Post date: Tuesday, January 24, 2012 - 09:34
Lab Report, 2011- 06

Th. Athanasopoulos, I. Minis

Rolling Horizon Planning of Vehicle Routers in a Multi-Environment, Under Review in EJOR, 2011

Post date: Tuesday, January 24, 2012 - 09:30

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