A prestressed precast beam is a type of beam that is stretched with traction elements. A common task in a factory of prestressed precast beams involves fulfilling, within a time horizon, the demand ordered by clients. A typical order includes beams of different lengths and types, with distinct beams potentially requiring different curing periods. We refer to the problem of planning such production as Heterogeneous Prestressed Precast Beams Multiperiod Production Planning (HPPBMPP). We formally define the HPPBMPP, argue its NP-hardness, and introduce four novel integer programming models for its solution and a size reduction heuristic (SRH). We propose six priority rules to produce feasible solutions. We perform computational tests on a set of synthetic instances that are based on data from a real-world scenario and discuss a case study. Our experiments suggest that the models can optimally solve small instances, while the SRH can produce high-quality solutions for most instances.

We introduce a novel variant of cutting production planning problems named Integrated Cutting and Packing Heterogeneous Precast Beams Multiperiod Production Planning (ICP-HPBMPP). We propose an integer linear programming model for the ICP-HPBMPP, as well as a lower bound for its optimal objective function value, which is empirically shown to be closer to the optimal solution value than the bound obtained from the linear relaxation of the model. We also propose a genetic algorithm approach for the ICP-HPBMPP as an alternative solution method. We discuss computational experiments and propose a parameterization for the genetic algorithm using D-optimal experimental design. We observe good performance of the exact approach when solving small-sized instances, although there are difficulties in finding optimal solutions for medium and large-sized problems, or even in finding feasible solutions for large instances. On the other hand, the genetic algorithm is shown to typically find good-quality solutions for large-sized instances within short computing times.

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This paper addresses an integrated lot-sizing and scheduling problem in the industry of consumer goods for personal care, a very competitive market in which the good customer service level and the cost management show up in the competition for the clients. In this research, a complex operational environment composed of unrelated parallel machines with limited production capacity and sequence-dependent setup times and costs is studied. There is also a limited finished-goods storage capacity, a characteristic not found in the literature. Backordering is allowed but it is extremely undesirable. The problem is described through a mixed integer linear programming formulation. Since the problem is NP-hard, relax-and-fix heuristics with hybrid partitioning strategies are investigated. Computational experiments with randomly generated and also with real-world instances are presented. The results show the efficacy and efficiency of the proposed approaches. Compared to current solutions used by the company, the best proposed strategies yield results with substantially lower costs, primarily from the reduction in inventory levels and better allocation of production batches on the machines.

This article discusses about the idealization and the Teaching Hand prototype development process. This software will be a platform dedicated to the teaching-learning process of Portuguese, as a second language, for deaf children. The teaching-learning methods for deaf people encounter great difficulties due to problems in acquiring Portuguese as L2. The main difficulties do not stem from deafness itself, but mainly the lack of rapprochement with the Portuguese. For this reason, the Teaching Hand demand offer the best educational conditions for creating an educational environment that encourages learning and enables the integration of the deaf in the form of equality to listeners. Resumo.O presente artigo discorre sobre a idealização e o processo de desenvolvimento do protótipo do Teaching Hand. Este software será uma plataforma voltada ao processo de ensino/aprendizagem da Língua Portuguesa, como segunda língua, por crianças surdas inseridas nos níveis fundamentais I e II. Os métodos de ensino-aprendizagem para sujeitos surdos encontram grandes empecilhos devido a problemas na aquisição da Língua Portuguesa como L2. As principais dificuldades não decorrem da surdez em si, mas, principalmente, da falta de aproximação com a Língua Portuguesa. Por esse motivo, o Teaching Hand procura ofertar as melhores condições pedagógicas para criação um ambiente educacional que estimule o aprendizado e possibilite a inserção do surdo em forma de igualdade aos ouvintes. Cenário de UsoEstudos recentes no âmbito linguístico têm apontado um crescente reconhecimento da linguagem enquanto lugar de interação. Entretanto, para uma grande maioria de sujeitos surdos, esta é uma realidade ainda distante.Por muito tempo, o surdo viveu à margem da sociedade e, em se tratando de linguagem, não dispunha de um método específico voltado para auxiliá-lo em suas limitações comunicacionais. No decorrer dos séculos, no entanto, tem-se proposto uma