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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avaliação de desempenho do algoritmo de um programa comercial para roteirização de veículos. / Evaluating the performance of an algorithm for vehicle routing in a commercial computer program.

Pelizaro, Cláudia 15 May 2000 (has links)
Este trabalho teve como objetivo a avaliação de um software comercial de roteirização de veículos. Tal software, o Delivery, se propõe a ser uma ferramenta de apoio à decisão na escolha da rotina operacional de coleta e/ou distribuição física de produtos, através da criação de roteiros alternativos, o que possibilita analisar a viabilidade de implantação da rotina operacional. A proposta original consistia em desenvolver uma metodologia para testar e avaliar a qualidade das soluções geradas pelo algoritmo deste sistema. O trabalho foi conduzido através de uma pesquisa bibliográfica dos problemas clássicos de roteirização e programação de veículos, abordando suas classificações, estratégias e técnicas de solução. Um estudo em empresas que utilizam procedimentos sistemáticos de roteirização foi realizado, com a intenção de caracterizar o cenário em que se desenvolve a atividade de distribuição física. Neste estudo foi possível identificar as características mais relevantes para sistemas comerciais de roteirização de veículos, bem como caracterizar os software utilizados pelas empresas em questão. Finalmente, realizou-se uma análise empírica comparativa entre os software Delivery e TransCAD através da aplicação de problemas testes encontrados na literatura que representam algumas classes do problema de roteirização de veículos, além da aplicação de um caso real. Resultados demonstraram que a heurística do software TransCAD apresenta melhor desempenho que a do software Delivery. / The aim of this work is to evaluate a commercial computer program for vehicle routing. The software, named Delivery, has been designed to be a decision-support tool for planning goods collection and/or distribution. Its capacity for creating several alternative routes is very useful in the analysis of possible operational schemes before their actual implementation. A methodology for testing and evaluating the quality of the solution generated by the algorithm has been applied in this work, after a comprehensive literature review of the traditional vehicle routing and scheduling problems, their classification, and solution techniques and strategies. A field study in some companies that actually use a similar tool for routing their fleets has been carried out, in order to better understand how the activity is performed in real world conditions. The most important characteristics of commercial vehicle routing systems has been also identified in the field study, as well as the software used by the studied companies. Finally, a comparative empirical analysis with the software Delivery and TransCAD has been carried out. In order to compare them, test problems available in the literature, that correspond to some of the most common vehicle routing problems, and a real case application were employed. The results have shown that the heuristic of TransCAD had a better performance than the one used in Delivery.
2

Avaliação de desempenho do algoritmo de um programa comercial para roteirização de veículos. / Evaluating the performance of an algorithm for vehicle routing in a commercial computer program.

Cláudia Pelizaro 15 May 2000 (has links)
Este trabalho teve como objetivo a avaliação de um software comercial de roteirização de veículos. Tal software, o Delivery, se propõe a ser uma ferramenta de apoio à decisão na escolha da rotina operacional de coleta e/ou distribuição física de produtos, através da criação de roteiros alternativos, o que possibilita analisar a viabilidade de implantação da rotina operacional. A proposta original consistia em desenvolver uma metodologia para testar e avaliar a qualidade das soluções geradas pelo algoritmo deste sistema. O trabalho foi conduzido através de uma pesquisa bibliográfica dos problemas clássicos de roteirização e programação de veículos, abordando suas classificações, estratégias e técnicas de solução. Um estudo em empresas que utilizam procedimentos sistemáticos de roteirização foi realizado, com a intenção de caracterizar o cenário em que se desenvolve a atividade de distribuição física. Neste estudo foi possível identificar as características mais relevantes para sistemas comerciais de roteirização de veículos, bem como caracterizar os software utilizados pelas empresas em questão. Finalmente, realizou-se uma análise empírica comparativa entre os software Delivery e TransCAD através da aplicação de problemas testes encontrados na literatura que representam algumas classes do problema de roteirização de veículos, além da aplicação de um caso real. Resultados demonstraram que a heurística do software TransCAD apresenta melhor desempenho que a do software Delivery. / The aim of this work is to evaluate a commercial computer program for vehicle routing. The software, named Delivery, has been designed to be a decision-support tool for planning goods collection and/or distribution. Its capacity for creating several alternative routes is very useful in the analysis of possible operational schemes before their actual implementation. A methodology for testing and evaluating the quality of the solution generated by the algorithm has been applied in this work, after a comprehensive literature review of the traditional vehicle routing and scheduling problems, their classification, and solution techniques and strategies. A field study in some companies that actually use a similar tool for routing their fleets has been carried out, in order to better understand how the activity is performed in real world conditions. The most important characteristics of commercial vehicle routing systems has been also identified in the field study, as well as the software used by the studied companies. Finally, a comparative empirical analysis with the software Delivery and TransCAD has been carried out. In order to compare them, test problems available in the literature, that correspond to some of the most common vehicle routing problems, and a real case application were employed. The results have shown that the heuristic of TransCAD had a better performance than the one used in Delivery.
3

Optimization Approaches for the (r,Q) Inventory Policy

Moghtader, Omid January 2024 (has links)
This thesis presents a comprehensive investigation into the performance and generalizability of optimization approaches for the single-echelon (r, Q) inventory management policy under stochastic demand, specifically focusing on demand characterized by a Poisson distribution. The research integrates both classical optimization techniques and advanced metaheuristic methods, with a particular emphasis on Genetic Programming (GP), to assess the effectiveness of various heuristics. The study systematically compares the performance of these approaches in terms of both accuracy and computational efficiency using two well-known datasets. To rigorously evaluate the generalizability of the heuristics, an extensive random dataset of 10,000 instances, drawn from a vast population of approximately 24 billion instances, was generated and employed in this study. Our findings reveal that the exact solution provided by the Federgruen-Zheng Algorithm consistently outperforms hybrid heuristics in terms of computational efficiency, confirming its reliability in smaller datasets where precise solutions are critical. Additionally, the extended Cooperative Coevolutionary Genetic Programming (eCCGP) heuristic proposed by Lopes et al. emerges as the most efficient in terms of runtime, achieving a remarkable balance between speed and accuracy, with an optimality error gap of only 1%. This performance makes the eCCGP heuristic particularly suitable for real-time inventory management systems, especially in scenarios involving large datasets where computational speed is paramount. The implications of this study are significant for both theoretical research and practical applications, suggesting that while exact solution, i.e., the Federgruen-Zheng Algorithm is ideal for smaller datasets, the eCCGP heuristic provides a scalable and efficient alternative for larger, more complex datasets without substantial sacrifices in accuracy. These insights contribute to the ongoing development of more effective inventory management strategies in environments characterized by stochastic demand. / Thesis / Master of Science (MSc)

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