Petersen, Hanne Løhmann

Nærværende afhandling, "Beslutningsstøtte til planlægning af multimodal transport med flere målsætninger", behandler to forskellige planlægningsproblemer fra transportsektoren; et fra godstransport og et fra passagertransport. Begge problemer er opstået som en kombination af problemer der allerede er velkendte fra operationsanalyselitteraturen, og bidrager med en ny synsvinkel på velkendte problemstillinger. De er begge af multimodal natur, og beskæftiger sig med problemer der opstår som en konsekvens af den kombinerede anvendelse af flere transportformer. Afhandlingen introducerer det dobbelte handelsrejsendes problem med flere stakke (double travelling salesman problem with multiple stacks - DTSPMS), som kombinerer rutelægning og LIFO-pakningsbetingelser (last-in-first-out). Efter en introduktion af problemet, diskuteres en række relaterede problemer fra litteraturen. Der præsenteres nogle overvejelser vedrørende øvre og nedre grænser for løsningsværdier, og illustrationer af nogle løsninger præsenteres for at give en fornemmelse af forholdet mellem løsninger til DTSPMS og til det traditionelle handelsrejsendes problem. Herefter præsenteres to artikler, der introducerer henholdsvis heuristiske og eksakte løsningsmetoder til problemet. Den heuristiske tilgang undersøger flere forskellige metaheuristiske løsningsmetoder, hvoraf en stornabolagssøgning (large neighbourhood search) opnår de bedste resultater. Der præsenteres resultater for probleminstanser af realistisk størrelse fra den virkelige verden, for mindre instanser, hvor den optimale løsning er kendt, og for større instanser, hvis størrelse ligeledes kan retfærdiggøres ud fra et virkelighedsnært perspektiv. Med henblik på at opnå optimale løsninger til DTSPMS introduceres og afprøves forskellige matematiske formuleringer i den anden artikel. Den mest lovende løsningstilgang er baseret på en dekomponering af problemet i en rutelægningsdel og en pakningsdel, og alle testede probleminstanser kan løses med denne metode. Det kombinerede vognløbsplanlægnings- og passagerserviceproblem (simultaneous vehicle scheduling and passenger service problem - SVSPSP) integrerer to problemstillinger som sædvanligvis betragtes adskilt og sekventielt, nemlig et køreplansproblem og et vognløbsproblem. SVSPSP åbner mulighed for at køreplansproblemet kan reoptimeres i forbindelse med vognløbsplanlægningsfasen, og betragter samtidig passagergener ved skift. Artiklen præsenterer en matematisk model for problemet, og en stornabolagsløsningsmetode implementeres. Problemet løses for en virkelighedsbaseret probleminstans som indeholder otte S-buslinier samt S-togene fra københavnsområdet, og resultaterne er lovende.This thesis treats two different planning problems from the transportation industry; one from freight transport and one from passenger transport. Each problem emerges as a combination of problems that are already known from the operational research literature, and introduces a new view of well-known issues. They both originate in the world of multimodality, and deal with problems that arise as a consequence of the combined use of several modes. The thesis introduces the Double Travelling Salesman Problem with Multiple Stacks (DTSPMS), which is a problem that combines routing and last-in-first-out loading constraints. After giving an introduction to the problem, a range of related problems from the literature are discussed. Some considerations are made regarding basic bounds for the problem, and illustrations of problem solutions are given to provide an impression of how solutions of the DTSPMS compare to solutions of the regular Travelling Salesman Problem. Next, two papers are presented, introducing respectively heuristic and exact solution procedures for the problem. The heuristic approach tests a variety of metaheuristic solution approaches, of which a large neighbourhood search obtains the best results. Results are provided for real-life instance sizes, for smaller instances for which the optimal solution value is known, and for some larger instances, which can also be justified from a real-life perspective. With the purpose of solving the DTSPMS to optimality, several different mathematical formulation are presented and tested in the second paper. The most promising approach is based on a decomposition of the problem into a routing part and a loading feasibility part, and all tested instances with 15 orders can be solved using this approach. The Simultaneous Vehicle Scheduling and Passenger Service Problem (SVSPSP) is an integration of two problems that are usually solved separately and sequentially, namely the timetabling problem and the Vehicle Scheduling Problem. The SVSPSP allows for the solution of the timetabling problem to be reoptimised when considering the vehicle scheduling phase, and considers passenger inconvenience at transfers at the same time. The paper presents a mathematical model of the problem, and the implementation of a large neighbourhood search solution procedure. The problem is solved for a real-life based problem instance, containing eight bus lines in the Greater Copenhagen area, and the results are promising

Online Research Database In Technology

Decision Support for Planning of Multimodal Transportation with Multiple Objectives

http://orbit.dtu.dk/ws/files/5010784/thesis.pdf

Decision Support for Planning of Multimodal Transportation with Multiple Objectives

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Online Research Database In Technology