Travelling salesman problem

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A HIGH PERFORMANCE ALGORITHM FOR SOLVING LARGE SCALE TRAVELLING SALESMAN PROBLEM USING DISTRIBUTED MEMORY ARCHITECTURES

A HIGH PERFORMANCE ALGORITHM FOR SOLVING LARGE SCALE TRAVELLING SALESMAN PROBLEM USING DISTRIBUTED MEMORY ARCHITECTURES

In this paper, we present an intelligent solution system for travelling salesman problem. The solution has three stages. The first stage uses Clustering Analysis in Data Mining to classify all customers by a number of attributes, such as distance, demand level, the density of customer, and city layout. The second stage introduces how to generate feasible routing schemes for each vehicle type. Specifically, a depth-first search algorithm with control rules is presented to generate feasible routing schemes. In the last stage, a genetic programming model is applied to find the best possible solution. Finally, we present a paradigm for using this algorithm for distributed memory architectures to gain the benefits of parallel processing.
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Solving the Travelling Salesman Problem Using the Ant Colony Optimization

Solving the Travelling Salesman Problem Using the Ant Colony Optimization

The Travelling Salesman Problem is one of the best known NP-hard problems, which means that there is no exact algorithm to solve it in polynomial time. The minimal expected time to obtain optimal solution is exponential. So, for that reason, we usually use heuristics to help us to obtain a “good” solution. Many algorithms were applied to solve TSP with more or less success. There are various ways to classify algorithms, each with its own merits. The basic characteristic is the ability to reach optimal solution: exact algorithms or heuristics.

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On the Solutions to the Travelling Salesman Problem using Nature Inspired Computing Techniques

On the Solutions to the Travelling Salesman Problem using Nature Inspired Computing Techniques

Algorithms such as ant colony optimization (ACO) and particle swarm optimization (PSO) that have been applied to the travelling salesman problem by various researchers in recent past have been briefly discussed in the present text. Some newly emerged techniques such as bacterial foraging optimization algorithm (BFOA), intelligent water drops (IWD), gravitational search algorithm (GSA) and river formation dynamics (RFD) which have been applied by scientists to solve TSP are also explored. Various results obtained by applying these techniques to different instances of travelling salesman problem that include up to 100 city problems have been included for comparison. Some of the techniques included in the present text produced very good results while others not. Among the algorithm discussed in the present text BFOA [12] is one with worst results. GSA [1] when hybridized with GA produced good results. C3DPSO [29] and IWD [21] clearly outperformed PSO. ACS [5] is competitive with these techniques for larger number cities.
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Hamiltonian cycle and TSP: A backtracking approach

Hamiltonian cycle and TSP: A backtracking approach

The Travelling salesperson problem is one of the problem in mathematics and computer science which had drown attention as it is easy to understand and difficult to solve. A Hamiltonian cycle of a directed graph G = (V, E) is a cycle that contains each vertex in V once. Backtracking is useful in the case of travelling salesman problem in a sense that assumes the number of cities is 10. The brute force solution will require about 10! trials. If we can use backtrack and in the halfway through tour that this is not going to be an optimal tour than we discard it saving the trials. Till now there are many papers published. The history of TSP is given in hoffman and wolfe [2]. The importance of TSP useful as it is the representative of a class of problem known as NP-complete. If one can find an efficient algorithm i.e. guaranteed to find an optimal solution in polynomial time [1]. If we can find the solution for TSP than all the problems in class NP can be solved in polynomial time. Till now no one had found polynomial algorithm. There are papers [3-10] which discuss about approximation of the TSP problem. In [11] the applications of the TSP were discussed. In this paper we had outlined the approach based on backtracking method.
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Formulações e algoritmos em programação inteira para o problema do caixeiro viajante com coleta e entrega sobre carregamento lifo

Formulações e algoritmos em programação inteira para o problema do caixeiro viajante com coleta e entrega sobre carregamento lifo

The Pickup and Delivery Travelling Salesman Problem can also be viewed as a re- stricted version of PDTSPMS. A more general case is the Precedence Constrained TSP, in which each vertex has one or more predecessors, and was first addressed by Balas et al. [1995]. The authors presented a polyhedral study and derived several classes of facet inducing inequalities, some of them used in the formulation proposed in this disserta- tion. Ascheuer et al. [2000] proposed a B&C algorithm for this problem, solving instances of the asymmetric TSP varying from 18 to 101 vertices and containing from four to 131 precedence relations among the vertices. A polynomial formulation for the problem was proposed by Sarin et al. [2005]. Gouveia and Pesneau [2006] proposed new extended for- mulations for the Precedence Constrained TSP using extra binary variables to model the precedence relation among the vertices. They derived a set of valid inequalities and de- veloped a B&C algorithm capable of obtaining the exact solution of one not previously solved instance. More recently, Dumitrescu et al. [2010] tackled the Pickup and Delivery Travelling Salesman Problem (PDTSP), in which a pick-up must precede its correspond- ing delivery. The authors presented polyhedral results and a B&C algorithm capable of solving instances not solved by previous approaches, involving up to 35 requests. The PDTSP was also solved with exact methods in Kalantari et al. [1985] and Hernández-Pérez and Salazar-González [2004]. For an extensive survey on pickup and delivery problems, the reader is referred to Berbeglia et al. [2007].
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Parallelization Of Traveling Salesman Problem Using Rocks Cluster

Parallelization Of Traveling Salesman Problem Using Rocks Cluster

The Travelling Salesman Problem (TSP) is famous as a resource extensive algorithm due to its complex computation. Given a number of cities representing vertices and edges representing paths, this algorithm would compute the shortest path for a person to make a round trip visiting all the cities only once.

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SOLUTION OF TRAVELING SALESMAN PROBLEM ON SCX BASED SELECTION WITH PERFORMANCE ANALYSIS USING GENETIC ALGORITHM

SOLUTION OF TRAVELING SALESMAN PROBLEM ON SCX BASED SELECTION WITH PERFORMANCE ANALYSIS USING GENETIC ALGORITHM

In this paper the implementation and performance of a new unconventional selection operator for Genetic Algorithm have been emphasized. The operator has been tuned specifically to solve the Travelling Salesman Problem. The proposed Selection Operator has been utilized based on Sequential Constructive Crossover. Here the parent’s structure has been chosen as selection criteria of a chromosome to survive for the next generations. Also it is observed that how much the low cost gene sequences of its parent’s structure to optimize the fitness of individuals has been maintained .It has been shown experimentally that the better convergence to optimal and near optimal solution compared to the traditional TSP with Conventional genetic operators has been achieved.
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Death of a Salesman: elementos da tragédia clássica no drama moderno de Arthur Miller

Death of a Salesman: elementos da tragédia clássica no drama moderno de Arthur Miller

O segundo elemento tratado por Aristóteles são os caracteres (os personagens), sobre os quais, em sua Poética, o autor define quatro características a serem apresentadas por eles. Os personagens devem ser bons, possuir caráter; adequados, ter comportamento adequado; semelhantes, dotados de verossimilhança (o possível e plausível); e constantes, coerentes e consistentes, mantendo o mesmo comportamento do início ao fim. Dessa maneira, é possível notar que Death of a salesman (1972) segue esses princípios relacionados aos personagens, visto que, primeiro, Willy é basicamente um homem bom e com boas intenções, prezando pela felicidade de sua família; segundo, seu comportamento, suas falhas e erros estão sempre ligados à boa intenção de ser o provedor da família; além disso, é um personagem verossímil e consistente, uma vez que ele mantém o mesmo comportamento durante a peça e seus atos são previsíveis do começo ao fim.
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Searching Less Perturbed Circular Orbits for a Spacecraft Travelling around Europa

Searching Less Perturbed Circular Orbits for a Spacecraft Travelling around Europa

he mathematical model used here for the perturbations is now explained in some detail. he problem deals with a system of nonlinear diferential equations, and we are using an extension of the theory proposed by Prado [15] to map a class of particular solutions. It is assumed that there is a spacecrat in a circular orbit around Europa. he forces acting in this spacecrat are the gravitational ield of Europa, considering the terms � 2 , � 3 , and � 22 , and the third-body perturbation due to Jupiter. hose terms were chosen because they are the most important ones in the gravitational poten- tial of Europa. Table 1 shows the numerical values of those constants. Note that the values are of the same order of magnitude; therefore, it is necessary to take all of them into account in the dynamical model. Other perturbations, like the gravitational ield of the other moons of Jupiter, are relevant only for very speciic orbits, near the orbits of one of those moons, so they are not included in the present research. he equations that describe the force ield are also shown in Table 1.
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‘Travelling Artists in Medieval and Renaissance Europe: An Introduction’

‘Travelling Artists in Medieval and Renaissance Europe: An Introduction’

papers were delivered in the session entitled Travelling Artists in Medieval and Renaissance Italy and Europe that I co-organized and convened with Jill Harrison (The Open University). The main aim of the session was to explore the variety of reasons that compelled artists to travel, and—whenever possible—provide the historic, social and cultural framework within which these artists lived and worked. Although the papers presented covered a period of over four centuries and dealt with artists working across Europe and beyond, the selection that is included here focuses on the neglected but crucial role of the artist, rather than on the art object itself, in the creation of cultural —either individual or collective, local or global— identity. We shall see how the shared sense of excellence between patrons and communities relied on the artists ability in conveying ideas and traditions and ultimately in fashioning their identity.
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Authentication: A Standard Problem or a Problem of Standards?

Authentication: A Standard Problem or a Problem of Standards?

Cost is widely seen as a problem for cell authentication, partly because the alternative (doing nothing) is always cheaper. It may surprise some scientists to know that the costs of either STR- or SNP-based authentication are quite low, in comparison to a small aliquot of antibody or chemical reagent. Admittedly, costs can grow dramatically if large panels of cell lines are used. However, there is a general lack of understanding as to how frequently cell lines need testing, making it difficult to predict overall costs. Standards and guidelines help to clarify what is necessary and sufficient for authentication, enabling broader compliance.
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A sustentabilidade como um wicked problem / Sustainability as a wicked problem

A sustentabilidade como um wicked problem / Sustainability as a wicked problem

É importante ressaltar que no presente trabalho foi mantido o termo “wicked” na Língua Inglesa não só por ser uma tradução difícil, mas, principalmente, porque poderia alterar o sentido no qual a palavra é usada e compreendida. No dicionário Michaelis (2012) as traduções indicadas para wicked são: mau, ruim, pecaminoso, vicioso; tais ideias não colaboram para o entendimento das teorias aqui expostas e por isso seu emprego seria impróprio. Ritchey (2011) faz uma ressalva com a mesma intenção quando recomenda que o termo wicked não deve ser compreendido como “malvado”, mas algo próximo de “traiçoeiro”. Na edição brasileira de Politics of the artificial, publicada em 2014, o termo utilizado para a tradução da expressão wicked problem foi “problema capcioso”. Ainda assim, optamos por manter o termo na sua grafia original. O mesmo ocorre com o termo tamed.
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POEMaS COM CInEMa antoLogia PoétiCa

POEMaS COM CInEMa antoLogia PoétiCa

Como todas as obras, há fragmentos que ficam: num filme, são pequenos gestos, uma frase, um esgar, um travelling , ou um plano que nos bate constantemente à porta da mente; pequenas frases de um livro, uma personagem inesquecível que tentamos personificar em alguém que não conhecemos; uma ideia que permanece misteriosamente, em momentos quotidianos, que nos sobressalta naquela noite de insónia; num poema, a junção tão improvável como real e crua de duas palavras numa frase – o mesmo encontro formulado por Sergei Eisenstein, em relação à montagem no cinema. Desta reunião de textos (que tenta obedecer a uma organização específica), e como não podia deixar de ser excepção, também nos poderão ficar alguns poemas. Propomos cinco: “Bu! Bu! Quem Tem Medo de Buñuel?”, de Alexandre O’Neill, um tanto histriónico, sem deixar de ser emotivo; o duro “Requiem para Pier Paolo Pasolini” de Eugénio de Andrade; “As Mulheres de Ozu”, de Fátima Maldonado, tão sensual como febril; “Cinema” de Carlos de
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A RETÓRICA DA PERFORMATIVIDADE A PARTIR DO DOCUMENTÁRIO “ESTAMIRA”

A RETÓRICA DA PERFORMATIVIDADE A PARTIR DO DOCUMENTÁRIO “ESTAMIRA”

O cinema direto americano (“Primárias” de Robert Drew e “Salesman” dos irmãos Maysles) e o Cinema Verité (“A pirâmide humana” de Jean Rouch) são exemplos desse tipo de documentário... O [r]

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Expressions of travelling in the portuguese 'romanceiro'

Expressions of travelling in the portuguese 'romanceiro'

Let us consider a case of motion through space and time which I believe falls short of "travelling" in "The Enchanted Princess + The Baffled Knight + The Lost Sister", wh[r]

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Behavioral event occurrence differs between behavioral states in Sotalia guianensis (Cetarctiodactyla: Delphinidae) dolphins: a multivariate approach

Behavioral event occurrence differs between behavioral states in Sotalia guianensis (Cetarctiodactyla: Delphinidae) dolphins: a multivariate approach

serve as a complementary strategy to herd and increase prey capture. In a T. truncatus population from Isla del Coco (Costa Rica), jumps were used to aid in capturing prey (A CEVEDO - G UTIERREZ 1999). Our data showed that Horizontal Jump, Side Flop and Partial Flop Ahead occurred most frequently in the Feeding state. Jumps in which dolphins entirely leave the wa- ter (Horizontal jump and Side flop) may produce the largest percussive effect in the water, which disrupts schools of fish. However, in the Travelling state, leaps may be used to increase swimming speed since friction is lower in the air and turbu- lence forces are lower (P URCELL 1977). The aerial events observed
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In the meantime or the (ab)use of online accessing during mobility

In the meantime or the (ab)use of online accessing during mobility

According to Mitchell, “working with the visual is (…) a mode of inquiry (a type of data elicitation). But there are two other aspects of the visual that are also critical. One relates to epistemology and how it is that we come to know what we know (and how to account for subjectivity).” This problem is especially meaningful “where it is the re- searcher herself who is the producer and interpreter” (Mitchell, 2011, pp. 4-5). And that happened in this research: the researcher was the producer of the images and had the power to chosen and that choice is subjective and addressed the research question. We were looking for the ICT presence and use. Maybe there could have been taken many other photographs without ICT. Also there are ethical issues involved and it is difficult to know whether you shall ask permission to photograph this kind of images to individuals or not. Besides that, the focus is the public beneath the individual. It is very difficult to operationalize an informed consent for this sort of data collection.
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An Effective Implementation of the Lin-Kernighan Traveling Salesman Heuristic

An Effective Implementation of the Lin-Kernighan Traveling Salesman Heuristic

Another method often used in studying the average performance of TSP heu- ristics is to solve problem instances consisting of random points within a rec- tangle under the Euclidean metric. The instances are solved for increasing val- ues of n and compared to the theoretical value for the expected length of an optimal tour (L opt ). A well-known formula is L opt (n, A ) = K √ n √ A when n cit- ies are distributed uniformly randomly over a rectangular area of A units [49]. That is, the ratio of the optimal tour length to √ n √ A approaches a constant K for N → ∞ . Experiments of Johnson, McGeoch and Rothenberg [50] suggest that K is approximated by 0.7124.
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A Computational Analysis of the Traveling Salesman and Cutting Stock Problems

A Computational Analysis of the Traveling Salesman and Cutting Stock Problems

The aim of this article is to perform a computational study to analyze the impact of formulations, and the solution strategy on the algorithmic performance of two clas- sical optimization problems: the traveling salesman problem and the cuting stock problem. In order to assess the algorithmic performance on both problems three de- pendent variables were used: solution quality, computing time and number of itera- tions. The results are useful for choosing the solution approach to each speciic problem. In the STSP, the results demonstrate that the multistage decision formula- tion is beter than the conventional formulations, by solving 90.47% of the instanc- es compared with MTZ (76.19%) and DFJ (14.28%). The results of the CSP demonstrate that the cuting paterns formulation is beter than the standard formu- lation with symmetry breaking inequalities, when the objective function is to mini- mize the loss of trim when cuting the rolls.
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