2015
Autores
Rodrigues, Ana Maria; Soeiro Ferreira, José;
Publicação
28th Conference of the European Chapter on Combinatorial Optimization
Abstract
Sectorization means dividing a set of basic units into sectors or parts, a procedure
that occurs in several contexts, such as political, health and school districting,
social networks and sales territory or airspace assignment, to achieve some goal
or to facilitate an activity. This presentation will focus on three main issues:
Measures, a new approach to sectorization problems and an application in waste
collection.
When designing or comparing sectors different characteristics are usually taken
into account. Some are commonly used, and they are related to the concepts
of contiguity, equilibrium and compactness. These fundamental characteristics
will be addressed, by defining new generic measures and by proposing a new
measure, desirability, connected with the idea of preference.
A new approach to sectorization inspired in Coulomb’s Law, which establishes a
relation of force between electrically charged points, will be proposed. A charged
point represents a small region with specific characteristics/values creating relations
of attraction/repulsion with the others (two by two), proportional to the
charges and inversely proportional to their distance. Finally, a real case about sectorization and vehicle routing in solid waste collection
will be mentioned.
2015
Autores
Gonçalves, R; Martins, J; Branco, F; Castro, MRG; Cota, MP; Barroso, J;
Publicação
UNIVERSAL ACCESS IN THE INFORMATION SOCIETY
Abstract
The current operator displays of Distributed Control Systems (DCS) are designed for 2D environments. This limits the full awareness situation of the industrial process, since it is distributed across multiple operator displays and requires the operator to navigate among them. This inspired the idea of creating a single operator display. Through an accurate and systematic literature review and by following the guidelines of design science methodology, it was possible to achieve a set of indicators and artefacts that corresponded to the defined goals. By developing a 2.5D/3D DCS interface application, the authors aimed at creating a way of allowing a full view of the entire manufacturing process, thus increasing the amount and the quality of information that is given to the operator and preventing unnecessary operation navigation between displays.
2015
Autores
Avila, P; Mota, A; Putnik, G; Costa, L; Pires, A; Bastos, J; Cruz Cunha, MM;
Publicação
INTERNATIONAL JOURNAL FOR QUALITY RESEARCH
Abstract
The problem of selecting suppliers/partners is a crucial and important part in the process of decision making for companies that intend to perform competitively in their area of activity. The selection of supplier/partner is a time and resource-consuming task that involves data collection and a careful analysis of the factors that can positively or negatively influence the choice. Nevertheless it is a critical process that affects significantly the operational performance of each company. In this work, trough the literature review, there were identified five broad suppliers selection criteria: Quality, Financial, Synergies, Cost, and Production System. Within these criteria, it was also included five sub-criteria. Thereafter, a survey was elaborated and companies were contacted in order to answer which factors have more relevance in their decisions to choose the suppliers. Interpreted the results and processed the data, it was adopted a model of linear weighting to reflect the importance of each factor. The model has a hierarchical structure and can be applied with the Analytic Hierarchy Process (AHP) method or Simple Multi-Attribute Rating Technique (SMART). The result of the research undertaken by the authors is a reference model that represents a decision making support for the suppliers/partners selection process.
2015
Autores
Mortazavi, SMB; Shiri, N; Javadi, MS; Dehnavi, SD;
Publicação
Ciência e Natura
Abstract
2015
Autores
Jacobs, B; Silva, A; Sokolova, A;
Publicação
JOURNAL OF COMPUTER AND SYSTEM SCIENCES
Abstract
This paper takes a fresh look at the topic of trace semantics in the theory of coalgebras. In the last few years, two approaches, somewhat incomparable at first sight, captured successfully in a coalgebraic setting trace semantics for various types of transition systems. The first development of coalgebraic trace semantics used final coalgebras in Kleisli categories and required some non-trivial assumptions, which do not always hold, even in cases where one can reasonably speak of traces (like for weighted automata). The second development stemmed from the observation that trace semantics can also arise by performing a determinization construction and used final coalgebras in Eilenberg-Moore categories. In this paper, we develop a systematic study in which the two approaches can be studied and compared. Notably, we show that the two different views on trace semantics are equivalent, in the examples where both approaches are applicable.
2015
Autores
Lobao, JA; Devezas, T; Catalao, JPS;
Publicação
ENERGY REPORTS
Abstract
The rational use of energy and energy-efficient environmental public street lighting is an important topic. In the design of new public lighting installations, national regulations containing energy-efficient guidelines are already used. Nevertheless, either in new installations or in reconstructions of existing lighting, designers do not generally consider all the available means to save energy. In installations of street lighting, energy consumption can be reduced by reducing the losses in the conductors, associated with the efficiency of the equipment, allowing better use of the available energy. The losses in the conductors must be analysed in conjunction with all the loads that contribute to the current in the sections of the installed street lighting. When opting for more efficient lamps and luminaires or lighting control systems, the current decreases in the sections covered with the most significant power loss due to proportionality with the square of the current. This decrease, often forgotten, is considered in this work in the investment analysis of efficiency and sustainable street lighting via simulation and experimental results. This analysis, combined with the features and operating parameters of the electrical installation, accounts for all the gains that can make a difference in the choice of efficient street lighting. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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