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Publications

2016

An Information Management Perspective of Supplier Selection Process in Manufacturing Networks

Authors
Messina, D; Barros, AC; Soares, AL;

Publication
COLLABORATION IN A HYPERCONNECTED WORLD

Abstract
The past decades have been characterized by an increasing interest of companies in international trade and significant foreign direct investments, which led to a shift from localized manufacturing companies to global manufacturing networks. The main goal of this research is to analyze the management of information within the process of supplier selection in the context of manufacturing networks. The adoption of field study methodology allows understanding how the supplier selection process is carried out in Multinational Companies (MNCs) in different manufacturing sectors. In particular, this paper aims at identifying the information that mother company and their subsidiary companies share during the supplier selection process, and how they access to this information.

2016

Evaluation of a Novel BEV Concept Based on Fixed and Swappable Li-Ion Battery Packs

Authors
Barreras, JV; Pinto, C; de Castro, R; Schaltz, E; Andreasen, SJ; Rasmussen, PO; Araujo, RE;

Publication
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS

Abstract
In this paper, a novel battery electric vehicle (BEV) concept based on a small fixed and a big swappable Li-ion battery pack is proposed in order to achieve longer range, lower initial purchase priceand lower energy consumption at short ranges. For short ranges, the BEV is only powered by the relatively small-fixed battery pack, without the large swappable battery pack. In this way, the mass of the vehicle is reduced and, therefore, the energy consumed per unit distance is improved. For higher ranges, the BEV is powered by both battery packs. This concept allows the introduction of subscription-based ownership models to distribute the cost of the large battery pack over the vehicle lifetime. A methodology is proposed for the analysis and evaluation of the proposed concept in comparison with a direct owned nonswappable single-pack BEV, proving that significant improvements on city fuel economy (up to 14%) and economic benefits are achievable under several scenarios. These results encourage further study of battery swapping service plans energy management strategies.

2016

Scalable adaptive collaborative filtering

Authors
Vinagre, J;

Publication

Abstract

2016

Aplicação do coeficiente RV em Controlo Estatístico da Qualidade

Authors
Adelaide Figueiredo; Fernanda Figueiredo;

Publication

Abstract

2016

Metaheuristics for the single machine weighted quadratic tardiness scheduling problem

Authors
Goncalves, TC; Valente, JMS; Schaller, JE;

Publication
COMPUTERS & OPERATIONS RESEARCH

Abstract
This paper considers the single machine scheduling problem with weighted quadratic tardiness costs. Three metaheuristics are presented, namely iterated local search, variable greedy and steady-state genetic algorithm procedures. These address a gap in the existing literature, which includes branch-and-bound algorithms (which can provide optimal solutions for small problems only) and dispatching rules (which are efficient and capable of providing adequate solutions for even quite large instances). A simple local search procedure which incorporates problem specific information is also proposed. The computational results show that the proposed metaheuristics clearly outperform the best of the existing procedures. Also, they provide an optimal solution for all (or nearly all, in the case of the variable greedy heuristic) the smaller size problems. The metaheuristics are quite close in what regards solution quality. Nevertheless, the iterated local search method provides the best solution, though at the expense of additional computational time. The exact opposite is true for the variable greedy procedure, while the genetic algorithm is a good all-around performer.

2016

An Allocation Scheme for IEEE 802.15.4-ZigBee Cluster-tree Networks

Authors
Leao, E; Vasques, F; Portugal, P; Moraes, R; Montez, C;

Publication
PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY

Abstract
The IEEE 802.15.4/ZigBee standards support the implementation of cluster-tree networks, which are a suitable topology to deploy wide-scale networks. In this type of topology, an important issue is the configuration of the superframe duration that is allocated to each of the network clusters. In this paper, we propose an allocation scheme for setting up these superframe duration values. The proposed scheme allocates adequate duration values for each cluster coordinator, based on the message load originated from its child nodes (including child coordinators and its descendants). The target of the proposed allocation scheme is to improve the network throughput and to reduce network congestion and dropped messages. Its main advantages are: 1) to have a balanced allocation of network resources to the different clusters; 2) the message generation at the application layer does not need to be synchronised with the beacon arrival; and 3) the message periods do not need to be multiple of the beacon interval.

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