Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Context: the design of the warehouse is a key factor in the configuration of logistics systems, as it can facilitate the timely management of materials, intermediate and/or final products, improving the time, cost and levels of customer service. To achieve this, experts help is required to integrate within the design an appropriate combination of storage, manipulation of materials and selection of orders. This level of integration, however, has not yet been achieved since the advances in the subject have been addressed from different aspects of the storage problem, but independently.Method: the article presents a method for warehouse layout design in two phases. The first phase defines the variables and parameters that are obtained from the planning of the production; the second phase consists of five stages that culminate in the integral design of the warehouse. In this last phase a modified version of an existing mathematical model of sizing is applied, where a new equation is added.Results: the method is applied to a company that supplies liquid polyurethane in the construction sector. The design generates four options for configuration of shipping and receiving docks and five storage options, where the best option generates an average area, mean real capacity and percentage average of storage utilization of 374,8 m2, 360 pallet and 93,8% respectively. These results are coherent with the dynamics of the company.Conclusions: the method allows evaluating options of the flow configuration and their respective sizing than may influence decisions of great importance in the operational capacity of the company in the short, medium and long term. In the future research is interesting to include new conditions, for example the compatibility of the method with different distributions to the traditional configuration of parallel shelves. 

Context: In the design process of Fuzzy Inference Systems based on Boolean and Kleenean Relations (FIS-BKR) there is a dilemma choosing the regular kleenean extensions of a given boolean function. The set of possible kleenean extensions of a boolean function has a lattice structure under the usual partial order of functions. The fuzzy convex combination proposed by Zadeh guarantees some properties related to this order.Method: The addition of a convex combiner just before the defuzzifier offers a solution to the above situation. The ISE (Integral Squared Error) and ITSE (Integral Time-weighted Squared Error) performance indexes were used on an application for tuning a liquid level control system.Results: The tuning process carried out on the FIS-BKR controller with fuzzy convex combiner using constant coefficients, implied an improvement of the controlled system up to 1.427% for ISE index and up to 21.99% for ITSE with respect to the extreme extensions.Conclusions: New evidence of convenient characteristics of FIS-BKR controllers with fuzzy convex combiner was presented when the performance indexes ISE and ITSE were evaluated. On the other hand, although in this work parameter tuning for convex combination was done by grid search (brute force), it would be interesting to study more effective optimization methods for this purpose.

Context: 3D printing can be used for a wide range of tasks such as the design and testing of prototypes and finished products in a shorter time. In mechanical engineering, prototype designs are continuously generated in academic class activities and final coursework projects by students and teachers. However, students show limitations while understanding the abstract concepts represented with such designs.Method: Firstly, a large scale 3D printer with improved technical specifications compared to traditional market options and similar price, was fabricated. By means of free software and hardware tools and easy-to-obtain alternative manufacturing materials, it was possible to decrease its manufacturing and operating costs. Then a set of study cases utilising the 3D printer in three different subject classes were designed and tested with two cohorts of students of Mechanical Engineering programme.Results: It was feasible to fabricate a cost-effective and practical 3D printer for constructing prototypes and pieces that benefit teaching and learning concepts in engineering and design areas. The experiments carried out in three subjects of engineering courses with second-year students, showed a similar trend of improving the average course grades, as it was observed in two cohorts in different terms.Conclusions: This type of low cost 3D printer obtained academic advantages as a didactic tool for the learning process in engineering and design subjects. Future work will consider applying this tool to other courses and subjects to further evaluate its convenience and effectivity.

Context: This paper presents a literature review of the Inventories Routing Problem (IRP) applied to supply chains of perishable products. Different approaches to solve this problem are identified and described in terms of structures, models and solution methods. Method: A systematic literature review is conducted searching in different bibliographic databases and selecting the most relevant studies within the period 2004 to 2017. The results are analyzed so as to propose a taxonomy to classify and compare the different approaches proposed to address this problem.Results: We identified that the majority of studies consider heuristic-based algorithms to solve the problem. Because of its computational complexity the methods resort to metaheuristics and mateheuristics combined with exact methods. Regarding the application to specific supply chains of perishable products, they refer mostly to processed foods, medicines, and human blood. The constraints that differentiate this problem from other types of IRP are useful life and deterioration.Conclusions: The conditions and particularities of the supply chain of perishables products imply the need to consider new variables, parameters, constraints and objective functions; in the reviewed studies it is not clearly defined the differences involved when considering the perishability of the products in the supply chain. Future research should take into account the multiple ways in which deterioration is carried out with factors such as temperature, light, oxygen, humidity and in some cases microorganisms. Also include in the models the cold chain, hygiene standards, air pollution, emissions of greenhouse gases, generation of waste, occupation of roads and other aspects related to City Logistics and Green Logistics.