Uma hiper-heurística é uma heurística que pode ser utilizada para lidar com qualquer problema de otimização, desde que a ela sejam fornecidos alguns parâmetros, como estruturas e abstrações, relacionados ao problema considerado. As hiper-heurísticas têm sido aplicadas a alguns problemas práticos e apresentadas como métodos de grande potencial, no que diz respeito à capacidade de possibilitar o desenvolvimento, em tempo bastante reduzido, de algoritmos capazes de lidar satisfatoriamente, do ponto de vista prático, com problemas de otimização complexos e pouco conhecidos. No entanto, é difícil situar as hiper-heurísticas em algum nível de qualidade e avaliar a robustez dessas abordagens caso não as apliquemos a problemas para os quais existam diversas instâncias disponíveis publicamente e já experimentadas por algoritmos relevantes. Este trabalho procura dar alguns passos importantes rumo a essas avaliações, além de ampliar o conjunto das hiper-heurísticas, compreender o impacto de algumas alternativas naturais de desenvolvimento e estabelecer comparações entre os resultados obtidos por diferentes métodos, o que ainda nos permite confrontar as duas diferentes classes de hiper-heurísticas que identificamos. Com essas finalidades em mente, desenvolvemos 3 novas hiper-heurísticas e implementamos 2 das hiper-heurísticas mais importantes criadas por outros autores. Para estas últimas, experimentamos ainda algumas extensões e modificações. Os dois métodos hiper-heurísticos selecionados podem ser vistos como respectivos representantes de duas classes distintas, que aparentemente englobam todas as hiper-heurísticas já desenvolvidas e nos permitem denominar cada um desses métodos como \"hiper-heurística de busca direta por entornos\" ou como \"hiper-heurística evolutiva indireta\". Implementamos cada hiper-heurística como uma biblioteca (em linguagem C), de forma a evidenciar e estimular a independência entre o nível em que se encontra a hiper-heurística e aquele onde se apresentam as estruturas e abstrações diretamente relacionadas ao problema considerado. Naturalmente, essa separação é de ingente importância para possibilitar a reutilização imediata das hiper-heurísticas e garantir que nelas haja total ausência de informações relativas a um problema de otimização específico. / A hyperheuristic is a heuristic that can be used to handle any optimization problem, provided that the algorithm is fed with some parameters, as structures and abstractions, related to the problem at hand. Hyperheuristics have been applied to some practical problems and presented as methods with great potential to allow the quick development of algorithms that are able to successfully deal, from a practical standpoint, with complex ill-known optimization problems. However, it\'s difficult to position hyperheuristics at some quality level and evaluate their robustness without applying them to problems for which there are many instances available in the public domain and already attacked by worthy algorithms. This work aims to give some important steps towards that process of evaluation, additionally increasing the number of available hyperheuristics, studying the impact of some natural development alternatives and comparing the results obtained by different methods, what also enables us to confront the two classes of hyperheuristics that we have identified. With those purposes in mind, we have developed 3 original hyperheuristics and implemented 2 of the most important hyperheuristics created by other authors. For those latter two approaches, we have also experimented with some modifications and extensions. The two methods we have chosen for implementation may be seen as respectively representing two distinct classes, which seem to contain all hyperheuristics developed so far and that allow us to classify any of these methods as either being a \"direct neighbourhood search hyperheuristic\" or an \"indirect evolutive hyperheuristic\". We have implemented each hyperheuristic as a library (in the C language), so as to clearly show and estimulate the independence between the level where the hyperheuristic is and that to which the structures and abstractions directly related to the problem at hand belong. Obviously, this separation of concerns is extremely important to make the immediate reuse of hyperheuristics possible and enforce in them the complete absence of information from a specific optimization problem.

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.

Made available in DSpace on 2016-12-23T14:05:52Z (GMT). No. of bitstreams: 1 Rosemberg Silva Salles.pdf: 2088047 bytes, checksum: b650ba6ed0d06eb04f22760620fd4cc1 (MD5) Previous issue date: 2013-05-21 / This work aims to develop a procedure for collecting and physical distribution of employees by a fleet of chartered buses with the support of a geographic information system by applying the vehicle routing problem for possible optimization of routes. We begin with a review of the literature on chartered transport of employees, as well as the problems of vehicle routing and geographic information systems. Then we propose a routing procedure, which characterizes and defines the problem of collection and delivery of employees, in addition to defining the criteria for route ptimization. For this purpose, we use the software TransCAD where you do the modeling and the resolution of the problem. The procedure was applied to a case study in a large company in the Metropolitan Region of Vitória in Espírito Santo State, which provides transport their own to their employees. We generated four scenarios, analyzing the efficiency of the routes in terms of distances, travel times and operating costs. The results generated from the procedure allowed us to determine in what scenarios the routes are more efficient / Este estudo tem o objetivo de desenvolver um procedimento de coleta e distribuição física de empregados por uma frota de ônibus fretada com o apoio de um sistema de informações geográficas, aplicando o problema de roteirização de veículos para uma possível otimização das rotas. Inicialmente é feita uma revisão de literatura sobre o transporte fretado de empregados, bem como dos problemas de roteirização de veículos e dos sistemas de informações geográficas. Em seguida é proposto um procedimento de roteirização, onde se caracteriza e delimita o problema de coleta e distribuição de empregados, além de definir os critérios de otimização de rotas. Para tanto, utiliza-se o software TransCAD no qual é feita a modelagem e proposta de resolução do problema. O procedimento foi aplicado a um estudo de caso em uma empresa de grande porte na Região Metropolitana da Grande Vitória, no Estado do Espírito Santo, que oferece transporte próprio as seus empregados. Foram gerados quatro cenários, onde se analisa a eficiência das rotas em termos de distâncias, tempos de viagem e custos operacionais. Os resultados gerados a partir do procedimento permitiram determinar em que cenários as rotas se mostram mais eficientes

Made available in DSpace on 2016-12-23T14:05:56Z (GMT). No. of bitstreams: 1 patricia rodrigues parte 1 p 1-46.pdf: 620096 bytes, checksum: 2df2214171a193891fb63f38e815ac0e (MD5) Previous issue date: 2011-09-16 / Problems that deal with wheelchair users public transportation are often solved by Dial a Ride Problem (DARP) with time window (Time Window TW). The goal of this type of problem is the minimization of the operation cost, in other words, the ride time respecting constraints like time windows for pickup and delivery of each user, the number of vehicles available and each vehicle capacity. This thesis proposes an exact Mixed Integer Linear Program model to solve the DARPTW. In order to apply the model in a real application, the model was tested with data provided by the Vitória City Hall Infrastructure and Transportation Secretary. The model was implemented using CPLEX software and the results showed that instances up to 20 wheelchair users can be solved optimally. Moreover, it was done an analysis for fleet used / Os problemas de transporte público de cadeirantes são comumente resolvidos pelo modelo Dial-a-Ride Problem (DARP) com janelas de tempo (Time Window - TW). Com base nas restrições de janela de tempo na origem e no destino de cada cliente, no número de veículos e na capacidade de cada um deles, deseja-se minimizar os custos de atendimento dessas demandas, ou seja, o tempo de viagem. A presente dissertação propõe um modelo de Programação Linear Inteira Mista para resolver o problema do DARP-TW. Visando uma aplicação do modelo no transporte público de cadeirantes foram utilizados dados reais fornecidos pela Secretaria de Transportes, Trânsito e Infraestrutura da Prefeitura de Vitória. O modelo foi executado no software CPLEX e os resultados mostraram que cenários com até 20 clientes podem ser resolvidos otimamente. Além disso, foi possível uma análise em relação à frota utilizada

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.

O objetivo deste trabalho é apresentar os conceitos da logística, em especial a logística de serviços, e algumas de suas ferramentas, como a roteirização de veículos e previsão de demanda por serviços, aplicadas aos serviços urbanos, neste caso o serviço de remendos em pavimentos, visando aumentar a eficiência desse serviço. O serviço de remendos, muitas vezes chamado de tapa-buracos, é uma atividade de manutenção comum nas cidades. Para observar a aplicação das ferramentas foi elaborado um estudo de caso na cidade de São Carlos. Dados sobre o serviço de remendos em pavimentos foram coletados e, com a ajuda de um sistema de informações geográficas – SIG, foram gerados roteiros que foram comparados com os dados originais. As rotas simuladas pelo SIG foram mais eficientes do que as praticadas na realidade, mostrando a utilidade dos conceitos da logística e também a utilidade do SIG na gerência da infra-estrutura urbana. A previsão de demanda por serviços de remendos não pôde ser observada devido à falta de dados históricos, fundamentais a essa etapa do trabalho. / The objective of this work is to introduce the concepts of logistics, especially the service logistics and some of its tools as the vehicle routing and the demand forecast for services, applied to the urban services, in this case the patching service in pavements in order to increase the efficiency of this service. The patching service, many times called tapa-buracos (in Brazil), is a common activity of maintenance in the cities. To observe the application of the tools one case study was elaborated in the city of São Carlos. Data about the patching service in pavements were collected and, helped by the geographic information system – GIS, routes were created and compared to the original data. The paths simulated by the GIS were more efficient than the real ones, showing the utility of the logistics concepts and also the utility of the GIS on the management of the urban infrastructure. The demand forecast for services of patching could not be observed due of the lack of historical data, essential to this part of the work.

We present solution methodologies for vehicle routing problems (VRPs) with stochastic demand, with a specific focus on the vehicle routing problem with stochastic demand (VRPSD) and the vehicle routing problem with stochastic demand and duration limits (VRPSDL). The VRPSD and the VRPSDL are fundamental problems underlying many operational challenges in the fields of logistics and supply chain management. We model the VRPSD and the VRPSDL as large-scale Markov decision processes. We develop cyclic-order neighborhoods, a general methodology for solving a broad class of VRPs, and use this technique to obtain static, fixed route policies for the VRPSD. We develop pre-decision, post-decision, and hybrid rollout policies for approximate dynamic programming (ADP). These policies lay a methodological foundation for solving large-scale sequential decision problems and provide a framework for developing dynamic routing policies. Our dynamic rollout policies for the VRPSDL significantly improve upon a method frequently implemented in practice. We also identify circumstances in which our rollout policies appear to offer little or no benefit compared to this benchmark. These observations can guide managerial decision making regarding when the use of our procedures is justifiable. We also demonstrate that our methodology lends itself to real-time implementation, thereby providing a mechanism to make high-quality, dynamic routing decisions for large-scale operations. Finally, we consider a more traditional ADP approach to the VRPSDL by developing a parameterized linear function to approximate the value functions corresponding to our problem formulation. We estimate parameters via a simulation-based algorithm and show that initializing parameter values via our rollout policies leads to significant improvements. However, we conclude that additional research is required to develop a parametric ADP methodology comparable or superior to our rollout policies.

We define an order cutoff for a retailer as a time in the day such that orders sent to the depot before this point will be delivered by tomorrow, and orders submitted after will be delivered by the day after tomorrow. The later a retailer’s cutoff, the sooner it receives its orders which helps it to maintain ideal inventory levels. Generally, not all retailers in a supply chain can have the latest cutoff since transportation takes a significant amount of time. This thesis tries to assign optimal order cutoffs to retailers. We call this an order cutoff assignment problem and we solve it using three different mathematical programming approaches. The approaches are exhaustive route generation and selection, a series of mixed integer programs, and branch-and-price. 60 sample problems were solved and results showed that branch-and-price is often the most effective method.

We define an order cutoff for a retailer as a time in the day such that orders sent to the depot before this point will be delivered by tomorrow, and orders submitted after will be delivered by the day after tomorrow. The later a retailer’s cutoff, the sooner it receives its orders which helps it to maintain ideal inventory levels. Generally, not all retailers in a supply chain can have the latest cutoff since transportation takes a significant amount of time. This thesis tries to assign optimal order cutoffs to retailers. We call this an order cutoff assignment problem and we solve it using three different mathematical programming approaches. The approaches are exhaustive route generation and selection, a series of mixed integer programs, and branch-and-price. 60 sample problems were solved and results showed that branch-and-price is often the most effective method.

The issues of global warming and climate change are a worldwide concern and the UK government has committed itself to major reductions in CO2 emissions, the most significant of the six greenhouse gases. Road transport currently accounts for about 22% of total UK emissions of CO2, and has been steadily rising. Therefore, initiatives are required to try and reduce the gas emissions in this sector. The aim of this research has been to develop a computer based vehicle routing model that calculates the overall amount of CO2 emitted from road journeys, as well as time and distance. The model has been used to examine a number of delivery strategies to assess how CO2 emissions vary. The aim has not been to produce new mathematical theories, but to produce an innovative basis for routing which will provide new information and knowledge about how CO2 emissions vary for different minimisation and congestion criteria. The approach used in this research brings together elements from transportation planning and environmental modelling combined with logistics based vehicle routing techniques. The model uses a digitised road network containing predicted traffic volumes, to which speed flow formulae are applied so that a good representation of speed can be generated on each of the roads. This means that the model is uniquely able to address the issue of congestion in the context of freight vehicle routing. It uses driving cycle data to apply variability to the generated speeds to reflect acceleration and deceleration so that fuel consumption, and therefore CO2, can be estimated. Integrated within the model are vehicle routing heuristics to enable routes to be produced which minimise the specified criterion of time, distance or CO2. The results produced by the model show that there is a potential to reduce CO2 emissions by about 5%. However, when other transport externalities are considered overall benefits are dependent on road traffic volumes.