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Publications

2016

Sustainability assessment framework for proactive supply chain management

Authors
Almeida, A; Bastos, J; Francisco, RDP; Azevedo, A; Ávila, P;

Publication
International Journal of Industrial and Systems Engineering

Abstract
Nowadays, it has been observed an increasing awareness and understanding on the subject of sustainable companies and business models, addressing multi-disciplinary approaches that cover not only economical problems, but also social and environmental challenges. Supply chains and especially collaborative networks managers are increasingly aware of these sustainability issues, continuously seeking to meet current human needs while preserving environmental safety. Only this way, focusing on its sustainable growing, it is possible to preserve companies' steadiness. In order to achieve this goal, sustainable networks must ensure that each partner is fully aligned and committed with economic, environmental and social axes that rule the network operational behaviour. Nevertheless, in order to achieve this level of maturity within such complex and turbulent environments, organisations need to improve the quality of their performance assessment approaches, integrating the different sustainability perspectives. To accomplish this, it is critical to establish specific indicators responsible to formalise and evaluate partners' behaviour, according to well-identified objectives, as well as fuse this information in a comprehensive and user-friendly way. This paper presents a new approach, based on a fuzzy logic-based algorithm, for sustainable network performance and risk assessment. © 2016 Inderscience Enterprises Ltd.

2016

Optimal planning and operation of aggregated distributed energy resources with market participation

Authors
Calvillo, CF; Sanchez Miralles, A; Villar, J; Martin, F;

Publication
APPLIED ENERGY

Abstract
This paper analyzes the optimal planning and operation of aggregated distributed energy resources (DER) with participation in the electricity market. Aggregators manage their portfolio of resources in order to obtain the maximum benefit from the grid, while participating in the day-ahead wholesale electricity market. The goal of this paper is to propose a model for aggregated DER systems planning, considering its participation in the electricity market and its impact on the market price. The results are the optimal planning and management of DER systems, and the appropriate energy transactions for the aggregator in the wholesale day-ahead market according to the size of its aggregated resources. A price-maker approach based on representing the market competitors with residual demand curves is followed, and the impact on the price is assessed to help in the decision of using price-maker or price-taker approaches depending on the size of the aggregated resources. A deterministic programming problem with two case studies (the average scenario and the most likely scenario from the stochastic ones), and a stochastic one with a case study to account for the market uncertainty are described. For both models, market scenarios have been built from historical data of the Spanish system. The results suggest that when the aggregated resources have enough size to follow a price-maker approach and the uncertainty of the markets is considered in the planning process, the DER systems can achieve up to 50% extra economic benefits, depending on the market share, compared with a non aggregated business-as-usual approach (not implementing DER systems).

2016

Machines and control systems for friction stir welding: A review

Authors
Mendes, N; Neto, P; Loureiro, A; Moreira, AP;

Publication
MATERIALS & DESIGN

Abstract
This survey presents a literature review on the machine and control systems applied in friction stir welding (FSW) with a special focus on the new trends, i.e., using robots and force control. The physical process of FSW is described and the main parameters that are relevant to select a machine and establish a control system are highlighted. The paper reviews in detail the role of the following parameters of a given machine for FSW: force, stiffness, accuracy, sensing, decision-making and flexibility capabilities. They will be compared in terms of the different machines, namely the conventional machine tools, dedicated FSW machines, parallel kinematic robots, and articulated robots. It is stated that articulated arm robots have enormous potentialities in the industrialization of the process, but they also have important limitations namely related to positional accuracy. A quality FSW weld produced by a robot depends on the fine tuning of some process parameters and force/motion control capabilities. Control systems can deal with these limitations. The different approaches to the control systems applied in FSW are presented and their advantages/drawbacks are discussed.

2016

Innovative Experimental Low Cost Electronics Operated Instrumentation for Wearable Health Systems with High Resolution Physiological Measurements

Authors
Cruz, DF; Rodrigues, EMG; Godina, R; Cabrita, CMP; Matias, JCO; Catalao, JPS;

Publication
2016 IEEE 16TH INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING (EEEIC)

Abstract
The aim of this paper is to present the development of an innovative experimental reflective pulse oximetry solution targeting wearable health system for daily monitoring purposes. The measurement of two common human physiological indicators is performed, which are the pulse rate and the blood oxygenation level (SpO(2)). The design options are detailed, covering photoplethysmographic (PPG) signals sensing architecture and post- processing digital filter operations. The high resolution of the physiological measures is achieved using sigma delta conversion technique. Conclusions are duly drawn.

2016

Experimental assessment of the components and materials of stone arch railway bridges

Authors
Arede, A; Costa, C; Topa Gomes, AT; Menezes, J; Silva, R; Goncalves, R; Morais, M;

Publication
MAINTENANCE, MONITORING, SAFETY, RISK AND RESILIENCE OF BRIDGES AND BRIDGE NETWORKS

Abstract

2016

Sampling Evolving Ego-Networks with forgetting Factor

Authors
Tabassum, Shazia; Gama, Joao;

Publication
IEEE 17th International Conference on Mobile Data Management, MDM 2016, Porto, Portugal, June 13-16, 2016 - Workshops

Abstract

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