Navegando por Palavras-chave "cutting stock problem"
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- ItemSomente MetadadadosAn evolutionary algorithm for the one-dimensional cutting stock problem(Wiley-Blackwell, 2011-01-01) Araujo, Silvio A.; Constantino, Ademir A.; Poldi, Kelly C. [UNIFESP]; Univ Estadual Paulista; Universidade Estadual de Maringá (UEM); Universidade Federal de São Paulo (UNIFESP)This paper deals with the one-dimensional integer cutting stock problem, which consists of cutting a set of available objects in stock in order to produce ordered smaller items in such a way as to minimize the waste of material. the case in which there are various types of objects available in stock in limited quantities is studied. A new heuristic method based on the evolutionary algorithm concept is proposed to solve the problem. This heuristic is empirically analyzed by solving randomly generated instances and the results are compared with other methods from the literature.
- ItemAcesso aberto (Open Access)A genetic symbiotic algorithm applied to the one-dimensional cutting stock problem(Sociedade Brasileira de Pesquisa Operacional, 2009-08-01) Golfeto, Rodrigo Rabello; Moretti, Antonio Carlos; Salles Neto, Luiz Leduino de [UNIFESP]; Universidade Federal Fluminense Escola de Engenharia Industrial Metalúrgica; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP)This work presents a genetic symbiotic algorithm to minimize the number of objects and the setup in a one-dimensional cutting stock problem. The algorithm implemented can generate combinations of ordered lengths of stock (the cutting pattern) and, at the same time, the frequency of the cutting patterns, through a symbiotic process between two distinct populations, solutions and cutting patterns. Working with two objectives in the fitness function and with a symbiotic relationship between the two populations, we obtained positive results when compared with other methods described in the literature.
- ItemAcesso aberto (Open Access)O problema de corte de estoque unidimensional multiperíodo(Sociedade Brasileira de Pesquisa Operacional, 2010-04-01) Poldi, Kelly Cristina [UNIFESP]; Arenales, Marcos Nereu; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)The Multiperiod Cutting Stock Problem arises embedded in the production planning and programming in many industries which have a cutting process as an important stage. Ordered items have different due date over a finite planning horizon. A large scale integer linear optimization model is proposed. The model makes possible to anticipate or not the production of items. Unused objects in inventory in a period become available to the next period, added to new inventory, which are acquired or produced by the own company. The mathematical model's objective considers the waste in the cutting process, and costs for holding objects and final items. The simplex method with column generation was specialized to solve the linear relaxation. Some preliminary computational experiments showed that the multiperiod model could obtain effective gains when compared with the lot-for-lot solution, which is typically used in practice. However, in real world problems, the fractional solution is useless. So, additionally, two rounding procedures are developed to determine integer solutions for multiperiod cutting stock problems. Such procedures are based on a rolling horizon scheme, which roughly means, find an integer solution only for the first period, since this is the solution to be, in fact, carried out. Finally, we conclude that the proposed model for multiperiod cutting stock problems allows flexibility on analyzing a solution to be put in practice. The multiperiod cutting problem can be a tool that provides the decision maker a wide view of the problem and it may help him/her on making decisions.
- ItemSomente MetadadadosSUFFICIENT CONDITION FOR PARTIAL EFFICIENCY IN A BICRITERIA NONLINEAR CUTTING STOCK PROBLEM(Edp Sciences S A, 2017) Arana-Jimenez, Manuel; Salles Neto, L. L. [UNIFESP]This work presents a sufficient criteria for partial efficient solutions of the cutting stock problem with two objectives. We consider two important objectives for an industry: number of processed objects (cost of raw materials) and number of different patterns (cost of setup). These optimality results are established through a new approach based on connections between discrete optimization and continuous vector optimization.
- ItemSomente MetadadadosTécnicas para minimização do número de padrões de corte no problema de corte de estoque(Universidade Federal de São Paulo (UNIFESP), 2015-10-27) Kobersztajn, Henrique Augusto [UNIFESP]; Poldi, Kelly Cristina Poldi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In this work, we present an approach to the one-dimensional cutting stock problem with one type of object and also with multiple types of objects. We consider two objectives in order to obtain the final solution: minimize the total length of cut objects and the number of different cutting patterns. Both objectives, generally conflicting, are dealt independently on the proposed methods. Initially, an exact solution to the cutting stock problem is obtained and, upon this solution, procedures are applied aiming different cutting patterns reduction. The minimizing pattern reduction process does not necessarily keep the initial minimum length of cut objects, however the increase of the length is allowed in a controlled way if it implies in more pattern reduction at the final solution. Computational tests are performed with random data to evaluate empirically this approach, and good results are obtained comparing to other methods presented in literature.