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Publications

2015

PROPOSAL OF AN EMPIRICAL MODEL FOR SUPPLIERS SELECTION

Authors
Avila, P; Mota, A; Putnik, G; Costa, L; Pires, A; Bastos, J; Cruz Cunha, MM;

Publication
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

Energy efficiency of lighting installations: Software application and experimental validation

Authors
Lobao, JA; Devezas, T; Catalao, JPS;

Publication
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/).

2015

Carotid intima-medial thickness, aortic stiffness and retinal microvascular signs provide evidence for optimal blood pressure target in hypertensive patients

Authors
Castro, P; Monteiro, A; Penas, S; Ferreira, C; Martins, L; Campilho, A; Polonia, J; Azevedo, E;

Publication
INTERNATIONAL JOURNAL OF STROKE

Abstract

2015

Proceedings of the First Workshop on Principles and Practice of Consistency for Distributed Data, PaPoC@EuroSys 2015, Bordeaux, France, April 21, 2015

Authors
Baquero, C; Serafini, M;

Publication
PaPoC@EuroSys

Abstract

2015

Evaluation of Load-Following Reserves for Power Systems with Significant RES Penetration considering Risk Management

Authors
Paterakis, NG; Sanchez de la Nieta, AAS; Catalao, JPS; Bakirtzis, AG; Ntomaris, A; Contreras, J;

Publication
2015 IEEE INTERNATIONAL CONFERENCE ON SMART ENERGY GRID ENGINEERING (SEGE 2015)

Abstract
In this study a novel two-stage stochastic programming based day-ahead joint energy and reserve scheduling model is developed. Demand-side as a reserve resource is explicitly modeled through responsive load aggregations, as well as large industrial consumers that directly participate in the scheduling procedure. Furthermore, a risk-hedging measure is introduced, namely the Conditional Value-at-Risk (CVaR), to analyze the behavior of energy and reserve scheduling by both the generation and the demand-side for a risk-averse ISO. The proposed methodology is tested on the practical non-interconnected insular power system of Crete, Greece, which is characterized by a significant penetration of Renewable Energy Sources (RES).

2015

Data Mining Frequent Temporal Events In Agrieconomic Time Series

Authors
Correa, FE; Gama, J; Correa, PLP; Alves, LRA;

Publication
IEEE LATIN AMERICA TRANSACTIONS

Abstract
The agricultural commodities are important to economies of several countries, especially in Brazil. Despite the amount of money involved, as knows that in agribusiness activities do not have accurate information in all the process. Therefore some research centers in Brazil, such as Center for Advanced Studies on Applied Economics - CEPEA, collect and provide daily price indices of these commodities, on several agricultural products, and spread information to these researchers markets, producers and formulators public policy. The idea is to understand the evolution and pattern for the time series of Grains price indices for seven years. The aim of this paper is find common patterns on time series, i.e. highlight events that happens frequently over seven year of daily grain prices quotation in several products. The results give an understanding of the dynamic of these grains time series, such as, some important aspects were detect was these products competes in fields for crops.

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