Solving the Traveling Salesman Problem Based on The Genetic Reactive Bone Route Algorithm whit Ant Colony System

[EN] The TSP is considered one of the most well-known combinatorial optimization tasks and researchers have paid so much attention to the TSP for many years. In this problem, a salesman starts to move from an arbitrary place called depot and after visits all of the nodes, finally comes back to the depot. The objective is to minimize the total distance traveled by the salesman.  Because this problem is a non-deterministic polynomial (NP-hard) problem in nature, a hybrid meta-heuristic algorithm called REACSGA is used for solving the TSP. In REACSGA, a reactive bone route algorithm that uses the ant colony system (ACS) for generating initial diversified solutions and the genetic algorithm (GA) as an improved procedure are applied. Since the performance of the Metaheuristic algorithms is significantly influenced by their parameters, Taguchi Method is used to set the parameters of the proposed algorithm. The proposed algorithm is tested on several standard instances involving 24 to 318 nodes from the literature. The computational result shows that the results of the proposed algorithm are competitive with other metaheuristic algorithms for solving the TSP in terms of better quality of solution and computational time respectively. In addition, the proposed REACSGA is significantly efficient and finds closely the best known solutions for most of the instances in which thirteen best known solutions are also found.Yousefikhoshbakht, M.; Malekzadeh, N.; Sedighpour, M. (2016). Solving the Traveling Salesman Problem Based on The Genetic Reactive Bone Route Algorithm whit Ant Colony System. International Journal of Production Management and Engineering. 4(2):65-73. doi:10.4995/ijpme.2016.4618.SWORD65734

Broker-based service-oriented content adaptation framework

Electronic documents are becoming increasingly rich in content and varied in format and structure. At the same time, user preferences vary towards the contents and their devices are getting increasingly varied in capabilities. This mismatch between rich contents and user preferences along with the end device capability presents a challenge in providing ubiquitous access to these contents. Content adaptation is primarily used to bridge the mismatch by providing users with contents that is tailored to the given contexts e.g., device capability, preferences, or network bandwidth. Existing content adaptation systems employing these approaches such as client-side, server-side or proxy-side adaptation, operate in isolation, often encounter limited adaptation functionality, get overload if too many concurrent users and open to single point of failure, thus limiting the scope and scale of their services. To move beyond these shortcomings, this thesis establishes the basis for developing content adaptation solutions that are efficient and scalable. It presents a framework to enable content adaptation to be consumed as Web services provided by third-party service providers, which is termed as “service-oriented content adaptation”. Towards this perspective, this thesis addresses five key issues – how to enable content adaptation as services (serviceoriented framework); how to locate services in the network (service discovery protocol); how to select best possible services (path determination); how to provide quality assurance (service level agreement (SLA) framework); and how to negotiate quality of service (QoS negotiation). Specifically, we have: (i) identified the key research challenges for service-oriented content adaptation, along with a systematic understanding of the content adaptation research spectrum, captured in a taxonomy of content adaptation systems; (ii) developed an architectural framework that provides the basis for enabling content adaptation as Web services, providing the facilities to serve clients’ content adaptation requests through the client-side brokering; (iii) developed a service discovery protocol, by taking into account the searching space, searching time, match type of the services and physical location of the service providers; (iv) developed a mechanism to choose the best possible combination of services to serve a given content adaptation request, considering QoS levels offered; (v) developed an architectural framework that provides the basis for managing quality through the conceptualization of service level agreement; and (vi) introduced a strategy for QoS negotiation between multiple brokers and service providers, by taking into account the incoming requests and server utilization and, thus requiring the basis of determining serving priority and negotiating new QoS levels. The performance of the proposed solutions are compared with other competitive solutions and shown to be substantially better

Wedding planner in a box

Marriage describes the connection of two souls who promise to become one heart. Everyone dreams their marriage to be nearly perfect and that will happen only if they are able to make their wedding plan with best packages. In this busy world, many couples delay their wedding mainly because of high budget required to meet their dream wedding ceremony. Wedding ceremony requires careful and meticulous planning from many aspects such as choosing the food, make up, decoration, and gifts

Branch-and-Cut for the Pickup and Delivery Traveling Salesman Problem with FIFO Loading

This paper introduces a branch-and-cut algorithm for a variant of the pickup and delivery traveling salesman problem in which pickups and deliveries must obey the first-in-first-out policy. We propose a new mathematical formulation of the problem and several families of valid inequalities which are used within the branch-and-cut algorithm. Computational experiments on instances from the literature show that this algorithm outperforms existing exact algorithms, and that some instances with up to 25 requests (50 nodes) can be solved in reasonable computing time

Optimização de processos na cadeia de abastecimento : o caso do transporte de mercadorias

Dissertação de mestrado em Engenharia de SistemasNum passado recente, tem-se verificado uma melhoria contínua das condições de transporte. As infraestruturas construídas, desde estradas a linhas ferroviárias tiveram como objectivo melhorar a qualidade de vida da população, diminuir o tempo e custos associados ao transporte e distribuição, quer de pessoas quer de mercadorias. Para que esta qualidade exista é necessário criar condições para tal, e assim é essencial optimizar as rotas dos veículos e a disposição das cargas transportadas. É nesta área que o presente trabalho se enquadra e de forma a contextualizar o problema e perceber o trabalho realizado na área até ao momento, é apresentado um resumo dos vários estudos desenvolvidos na área num capítulo de revisão de literatura. A realização desta dissertação foi constituída por duas fases distintas. Uma primeira fase de pesquisa de aplicações internacionais e nacionais que permitem optimizar rotas, na qual para as aplicações internacionais só foram analisadas aquelas que consideram restrições dos produtos transportados como o peso, altura, comprimento, largura e volume. Na análise das aplicações são descritas as suas funcionalidades e os principais clientes. Adicionalmente, e caso as aplicações tenham um módulo que trata do carregamento dos veículos, é feita a sua descrição. No fim dessa fase, é apresentada uma análise crítica das aplicações e uma tabela de síntese onde são apresentadas as suas principais características. O objectivo da segunda fase foi desenvolver e testar várias abordagens heurísticas para o problema de encaminhamento de veículos com restrições de carga a duas dimensões (2L-CVRP). Os testes de desempenho dessas heurísticas foram realizados sobre as mesmas instâncias usadas no trabalho desenvolvido por Iori (Iori, Salazar-Gonzalez, & Vigo, 2007) na qual garante resultados óptimos recorrendo a um algoritmo exacto. O problema em estudo é caracterizado por um depósito central onde estão colocados diversos veículos que têm a função de transportar encomendas efectuadas por clientes. O objectivo é minimizar tanto a distância total percorrida pelos veículos assim como o número de veículos utilizados. No final, temos uma série de veículos, em que cada um tem uma rota ordenada de clientes. Comparando os resultados das heurísticas com o algoritmo exacto, é natural que os resultados das heurísticas sejam piores no que diz respeito ao número de veículos utilizados e às distâncias percorridas. Contudo, a motivação esteve em tentar aproximar-se da qualidade dos resultados do algoritmo exacto em tempos computacionais bem menores. Nos três algoritmos desenvolvidos foram identificadas três zonas críticas, as estratégias de selecção dos clientes, a estratégia de colocação de itens nos veículos e a estratégia para controlar a distância percorrida – raio de movimentação dos veículos.In the recent past, there has been a continuous improvement of transport conditions. The infrastructures built, from roads to railways lines, were aimed to improve the population life quality, decrease the time and costs associated to the transport and distribution of people and goods. For this quality to exist, it is necessary to create conditions for that, and so it is essential to optimise the vehicle routing and the arrangement of the cargoes. This is the context of the current work and in order to understand what was done, a summary of several studies is presented in a state of art chapter. The development of this dissertation was composed by two distinct phases. An initial research phase of international and national software that allows routing optimization was made and, in the case of international software, we only analysed those who consider cargoes restrictions like, weight, height, length, width and volume. In the software analysis are described their main features and major customers and, if they have a module that deals with the vehicle loading, its description is made. At the end of this phase, a critical analysis and a summary table with the software main features are presented. The aim of the second stage was to develop and test heuristic approaches to the vehicle routing problem with two-dimensional loading constraints (2L-CVRP). Performance tests on this heuristics were performed on the same instances presented in Iori´s work (Iori, Salazar-Gonzalez, & Vigo, 2007), in which an exact algorithm was used to ensure optimal results. The problem features a central depot, where various vehicles are placed and each has the function of transporting orders placed by customers. The main objective is to minimize the total travelled distance and the number of vehicles used. In the end, we have a set of vehicles, in which, each has an ordered rout of clients. Following this approach and to provide a basis for comparison, three constructive heuristics were developed in order to have access to a range of different outcomes and so, in addition of being compared with the exact algorithm, the developed algorithms can be compared between them. The items that are used for analysis are, the number of vehicles used in an instance, the total distance travelled and the runtime. When compared with the exact algorithm, it is natural that the heuristics present worse results in terms of number of vehicles used and total distance travelled. However, the motivation was to try to approach the quality of the results presented by the exact algorithm, in less time. In the three algorithms developed, we identified three critical areas, the customers selection strategy, the placement of items in vehicles strategy and the control of distance strategy - radius of movement by vehicles between clients

Otimização dos circuitos de distribuição milk-run numa empresa do sector automóvel

Nos dias de hoje, a competição paralela entre as empresas e os clientes muito meticulosos, torna o mundo empresarial mais exigente. A presente dissertação, surge com o intuito de criar um modelo de roteamento capaz de definir as rotas de distribuição, otimizando o conjunto das mesmas. Associado a estas, muitas vezes uma má distribuição, é geralmente despendido tempo e recursos desnecessários às empresas. Desenvolvida num ambiente empresarial do sector automóvel, e de forma a melhorar todo o processo dos circuitos milk-run, foi criada uma ferramenta de apoio à decisão, alicerçada num modelo matemático de programação inteira, para as rotas do edifício de montagem manual. A ferramenta de apoio à decisão, utilizou dados de planos de produção referentes a Julho e Agosto de 2018, sendo resolvido o cálculo do modelo matemático no software IBM ILOG CPLEX 12.0.8. Para este período, foi testado um modelo matemático com foco na minimização do número de veículos, demonstrando que o mesmo otimizava o conjunto de milk-runs no parque de produção, mas não otimizava o roteamento. De forma a obter melhores resultados, foi modificada a função objetivo do modelo matemático, de forma a conjugar o roteamento de veículos com a minimização do tempo de ciclo dos comboios logísticos, garantindo a minimização do número de veículos. Assim, obtendo o melhor dos dois “mundos”, foi possível otimizar a quantidade de veículos necessários em dois para o transporte de placas, eliminando custos à empresa no que concerne a contratações, compra e manutenção de veículos e eliminar qualquer tipo de paragem de linhas por falta de abastecimento devido a atrasos no abastecimento. Foram ainda criadas ilustrações das rotas realizadas por cada milk-run. Em suma, a ferramenta de apoio à decisão criada demonstrou ser eficiente apresentando melhorias face à sistemática existente.Nowadays, the parallel competition between companies and meticulous customers, makes the business world more demanding. The present thesis aims to create a routing model capable of defining and optimizing the distribution routes. The poor distribution usually associated with these causes the loss of time and necessary resources to the companies. Developed in a corporative environment in the automotive sector, and in order to improve the entire process of the milk-run circuits, a decision-support tool, based on a mathematical model of integer programming, was created for the routes of the manual assembly building. The decision support tool used production plans data for July and August 2018, solving the mathematical model calculation in IBM ILOG CPLEX 12.0.8 software. During this period of time, a mathematical model was tested focusing on minimizing the number of vehicles. This mathematical model optimized the set of milk-runs in the production park, but did not optimize the routing. In order to obtain better results, the objective function of the mathematical model was modified, in order to combine the routing of vehicles with the minimization of the logistics trains cycle time, ensuring the number of vehicles minimization. Thus, it was possible to optimize the number of vehicles needed for the transport of plates, eliminating costs to the company regarding to hiring, purchase and maintenance of vehicles and eliminate any kind of line stop due to lack of supply caused by delays in supply. Illustrations of the routes performed by each milk-run were also created. In conclusion, the developed decision support tool proved to be efficient and presented improvements in relation to the existing systematic

Constrained Task Assignment and Scheduling on Networks of Arbitrary Topology.

This dissertation develops a framework to address centralized and distributed constrained task assignment and task scheduling problems. This framework is used to prove properties of these problems that can be exploited, develop effective solution algorithms, and to prove important properties such as correctness, completeness and optimality. The centralized task assignment and task scheduling problem treated here is expressed as a vehicle routing problem with the goal of optimizing mission time subject to mission constraints on task precedence and agent capability. The algorithm developed to solve this problem is able to coordinate vehicle (agent) timing for task completion. This class of problems is NP-hard and analytical guarantees on solution quality are often unavailable. This dissertation develops a technique for determining solution quality that can be used on a large class of problems and does not rely on traditional analytical guarantees. For distributed problems several agents must communicate to collectively solve a distributed task assignment and task scheduling problem. The distributed task assignment and task scheduling algorithms developed here allow for the optimization of constrained military missions in situations where the communication network may be incomplete and only locally known. Two problems are developed. The distributed task assignment problem incorporates communication constraints that must be satisfied; this is the Communication-Constrained Distributed Assignment Problem. A novel distributed assignment algorithm, the Stochastic Bidding Algorithm, solves this problem. The algorithm is correct, probabilistically complete, and has linear average-case time complexity. The distributed task scheduling problem addressed here is to minimize mission time subject to arbitrary predicate mission constraints; this is the Minimum-time Arbitrarily-constrained Distributed Scheduling Problem. The Optimal Distributed Non-sequential Backtracking Algorithm solves this problem. The algorithm is correct, complete, outputs time optimal schedules, and has low average-case time complexity. Separation of the task assignment and task scheduling problems is exploited here to ameliorate the effects of an incomplete communication network. The mission-modeling conditions that allow this and the benefits gained are discussed in detail. It is shown that the distributed task assignment and task scheduling algorithms developed here can operate concurrently and maintain their correctness, completeness, and optimality properties.Ph.D.Aerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91527/1/jpjack_1.pd