The single machine serial batch production scheduling with outsourcing allowed

Razmatramo nekoliko problema planiranja proizvodnje u serijama s dopuštenom mogućnošću ugovaranja proizvodnje s vanjskim proizvođačem (outsourcing). Postoji mogućnost da se svaki posao obavi na vlastitom stroju ili se ugovori s drugim poduzećem. Cilj je smanjiti ponderirani iznos cijene planirane proizvodnje i ukupne cijene outsourcinga. Razmatramo tri klasične objektivne funkcije programiranja. Prva je ukupno vrijeme izvršenja, druga je maksimalno kašnjenje, a treća je ponderirani broj kasnih poslova. Za svaki problem izvodima učinkovit dinamički algoritam programiranja koji minimalizira ukupni trošak.We consider several serial batch scheduling problems with outsourcing allowed. Each job can be either processed on the in-house machine or outsourced. The objective is to minimize the weighted sum of the scheduling cost and the total outsourcing cost. We discuss three classical scheduling objective functions. The first is the total completion time, the second is the maximum lateness, and the third is the weighted number of late jobs. For each problem, we derive an efficient dynamic programming algorithm that minimizes the total cost

Scheduling with subcontracting options

Department of Logistics2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Sistemática para alocação, sequenciamento e balanceamento de lotes em múltiplas linhas de produção

Diante dos desafios impostos pelo sistema econômico, características dos mercados e exigências dos clientes, as empresas são forçadas a operar com lotes de produção cada vez menores, dificultando a gestão de operações e a otimização dos sistemas produtivos. Desse modo, intensifica-se nos meios corporativos e acadêmicos a busca por abordagens que possibilitem a criação de diferenciais competitivos de mercado, sendo esta a justificativa prática deste trabalho, que propõe uma sistemática integrada para alocação, sequenciamento e balanceamento de lotes em um horizonte de programação em múltiplas linhas de produção em um sistema multiproduto com operadores polivalentes. A sistemática proposta foi dividida em três fases. A primeira fase utiliza um algoritmo genético multiobjetivo com o intuito de determinar a linha de produção em que cada lote será produzido. A segunda fase é responsável pelo sequenciamento dos lotes produtivos e se apoia em uma alteração da regra Apparent Tardiness Cost (ATC). Na terceira fase utilizou-se o método Ranked Positional Weight (RPW) para balancear a distribuição das tarefas entre os operadores polivalentes de cada linha de produção, respeitando a precedência das tarefas. A sistemática foi aplicada em dados reais do segmento têxtil, aprimorando os indicadores produtivos e de entrega e conferindo maior flexibilidade ao processo frente à demanda sazonal.Faced with the challenges imposed by the economic system, characteristic of the markets and requirements of the customers, the companies are forced to operate with smaller production batches, making it difficult to manage operations and optimization of the production systems. In this way, the search for improvements that allow the creation of competitive differentials of market is intensified in the corporate and academic circles. This is the practical justification for this work, which proposes an integrated systematics for the allocation, sequencing and balancing of batches in a horizon of programming in multiple production lines in a multiproduct system with multipurpose operators. The systematic proposal was divided into three phases. The first phase uses a multiobjective genetic algorithm with intention to determine the production line in which each batch will be produced. The second phase is responsible for the sequencing of productive batches and is based on a change in the rule Apparent Tardiness Cost (ATC). In the third phase the method Ranked Positional Weight (RPW) was used to balance the distribution of the tasks between the multipurpose operators of each line of production, respecting the precedence of the tasks. The systematics was applied in real data of the textile segment, improving the productive and delivery indicators and giving greater flexibility of the process against the seasonal demand

Integrated scheduling of production and logistics operations of a multi-plant manifacturer serving a single customer area

Ankara : The Department of Industrial Engineering and the Institute of Engineering and Science of Bilkent University, 2009.Thesis (Master's) -- Bilkent University, 2009.Includes bibliographical references leaves 129-132.Increasing market competition forces manufacturers to continuously reduce their leadtimes by minimizing the total time spent in both production and distribution. Some studies in the relevant literature indicate that scheduling production and logistics operations in a coordinated manner leads to improved results. This thesis studies the problem of scheduling production and distribution operations of a manufacturer serving a single customer area from multiple identical production plants dispersed at different geographical locations. The products are transported to the customer area by a single capacitated truck. The setting is inspired by the operations of a leading soft drink manufacturer, and the objective is set in line with their needs as the minimization of the total completion time of the jobs. The completion time of a job is defined as the time it reaches at the customer area. We consider both this general problem and four special cases motivated by common practical applications. We prove that both the main problem and three of its special cases are NP-hard at least in the ordinary sense. We develop mixed integer programming (MIP) models for all these problems and propose a pseudo-polynomial dynamic programming mechanism for the remaining special case. Since the MIP models are able to provide optimal solutions only for small instances in a reasonable amount of time, heuristics are also proposed to solve larger instances. Fast lower bounds are developed to facilitate the performance assessment of these heuristics in medium and large instances. Evidence from extensive computational experimentation suggests that the proposed heuristics are both efficient and effective.Çelen, MerveM.S