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Publications

Publications by Alvaro Luiz Júnior

2016

A surveyonheuristics for the two-dimensional rectangular strip packing problem

Authors
Oliveira, JF; Neuenfeldt, A; Silva, E; Carravilla, MA;

Publication
Pesquisa Operacional

Abstract
Two-dimensional rectangular strip packing problems belong to the broader class of Cutting and Packing (C&P) problems, in which small items are required to be cut from or packed on a larger object, so that the waste (unused regions of the large object) is minimized. C&P problems differ from other combinatorial optimization problems by the intrinsic geometric constraints: items may not overlap and have to be fully contained in the large object. This survey approaches the specific C&P problem in which all items are rectangles, therefore fully characterized by a width and a height, and the large object is a strip, i.e. a rectangle with a fixed width but an infinite height, being the problem’s goal to place all rectangles on the strip so that the height is minimized. These problems have been intensively and extensively tackled in the literature and this paper will focus on heuristic resolution methods. Both the seminal and the most recent approaches (from the last decade) will be reviewed, in a rather tutorial flavor, and classified according to their type: constructive heuristics, improvement heuristics with search over sequences and improvement heuristics with search over layouts. Building on this review, research gaps are identified and the most interesting research directions pointed out. © 2016 Brazilian Operations Research Society.

2016

The performance measurement of innovation and competitiveness in the telecommunications services sector

Authors
Nora, LDD; Siluk, JCM; Júnior, ALN; Soliman, M; Nara, EOB; Furtado, JC;

Publication
International Journal of Business Excellence

Abstract
From the growing trend of the services sector participation in the Brazilian economic scenario, the demand for studies on this subject seek to deepen the understanding about the behaviour of the aspects that influence the occurrence of such evolution. Following this sense, the present study aimed to propose a diagnostic model to measure de performance of innovation and competitiveness in the telecommunications service sector, providing resources to develop strategies, in order to turn the company capable of acting in a position according to direct and indirect main competitors, being development guided by five factors: service production, technology, human resources, finance and marketing. Once constructed the model, the implementation proved to be valid, presenting itself as a practical tool to support managers and consultants in the overall assessment of the company, allowing also to analyse its performance situation regarding to the development of competitive forms of positioning. Copyright © 2016 Inderscience Enterprises Ltd.

2016

The scientific research context of urban transports for Bus Rapid Transit systems applications

Authors
Neuenfeldt Júnior, AL; Siluk, JCM; Paris, SRD;

Publication
Journal of Transport Literature

Abstract

2016

The use of artificial intelligence for the prediction of productivity parameters in swine culture

Authors
Sangoi, LF; Kessler, AM; Neuenfeldt Júnior, AL; Siluk, JCM; Ribeiro, AML; Soliman, M;

Publication
Pesquisa Operacional

Abstract
In similar conditions of food handling and genetics, there are large differences in the final productivity of farms, resulting from inherent factors of the production system. This fact predisposes the need of studies on optimizing the rearing conditions of the farms, in order to verify the main limitations for the producers. Therefore, the present study aims to generate predictions of the swine productivity in the finishing phase, using variables related to their profiles and the production results achieved. 107 farmers belonging to a swine cooperative were considered in the study, located in 47 counties at the Taquari valley region, Brazil. Predictions were generated through the aid of neural networks, and the findings show that Artificial Neural Networks (ANN) can predict the productivity variables Feed Conversion, Mortality and Average Daily Gain for the proposed case. © 2016 Brazilian Operations Research Society.

2018

The Two-Dimensional Strip Packing Problem: What Matters?

Authors
Neuenfeldt Junior, A; Silva, E; Miguel Gomes, AM; Oliveira, JF;

Publication
OPERATIONAL RESEARCH

Abstract
This paper presents an exploratory approach to study and identify the main characteristics of the two-dimensional strip packing problem (2D-SPP). A large number of variables was defined to represent the main problem characteristics, aggregated in six groups, established through qualitative knowledge about the context of the problem. Coefficient correlation are used as a quantitative measure to validate the assignment of variables to groups. A principal component analysis (PCA) is used to reduce the dimensions of each group, taking advantage of the relations between variables from the same group. Our analysis indicates that the problem can be reduced to 19 characteristics, retaining most part of the total variance. These characteristics can be used to fit regression models to estimate the strip height necessary to position all items inside the strip.

2017

A performance measurement decision support system method applied for technology-based firms' suppliers

Authors
Mairesse Siluk, JCM; Kipper, LM; Benitez Nara, EOB; Neuenfeldt Junior, AL; Dal Forno, AJ; Soliman, M; da Silva Chaves, DMD;

Publication
JOURNAL OF DECISION SYSTEMS

Abstract
The present article proposes a mathematical decision support system model to measure the performance of incubated technology-based firms (TBFs) suppliers. The research was conducted based on three steps: (1) a literature review, in order to parameterise the research in relation to the theme; (2) the construction of a measuring system, based on the presumptions permeated by the analytic hierarchy process (AHP); and (3) the application of the system at three companies. The findings demonstrated the mathematical modelling developed is capable of providing satisfactory results to the reality of the sector studied, presenting the situation of the suppliers evaluated, independent of the nature of the indicated critical success factors (CSFs). Also, this tool supports companies by providing a strong foundation to organise the information regarding the service level delivered by each supplier, according to previous research on the theme.

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