2018
Autores
Metz, D; Saraiva, JT;
Publicação
ELECTRIC POWER SYSTEMS RESEARCH
Abstract
Over the last few years, electrical storage and especially battery systems have seen a strong rise in interest. In several countries, as for instance in Germany, lithium-ion batteries are now commonly deployed in end-consumer installations to shift local generation from photovoltaic systems in time. A further application for storage is price arbitrage, which corresponds to an operation strategy benefitting from price differentials. In this work, we describe a Mixed Integer Problem to optimize the storage dispatch considering both the 15- and the 60-min auctions in use in Germany. Furthermore, in addition to the calendric lifetime, the limitation to a certain number of cycles is considered in the evaluation. Last, it was conducted a sensitivity analysis to identify the price volatility level that is required to generate a profit from arbitrage operations. Therefore, a market price process with adjustable parameters has been implemented.
2018
Autores
Pereira, T; Muguruza, J; Mária, V; Vilaprinyo, E; Sorribas, A; Fernandez, E; Fernandez-Armenteros, JM; Baena, JA; Rius, F; Betriu, A; Solsona, F; Alves, R;
Publicação
Ultrasound in Medicine & Biology
Abstract
2018
Autores
Almeida, F;
Publicação
MANAGEMENT RESEARCH AND PRACTICE
Abstract
The need for innovation and the ability to transfer knowledge to society and industry are essential for the development of current economy. In this sense, universities play a crucial role in this mission, and university spin-offs have become one of the most popular mechanisms of academic knowledge transfer. The purpose of this paper is to perform a literature review in the field of university spin-offs. The adopted methodology starts by creating a conceptual map of the various research areas around university spin-offs, followed by the identification of the most predominant studies in the field taking into account the number of citations. The findings indicate that the main explored dimensions in the university spin-offs research include the process of technology transfer, the role of university in the society, the regional context of the university and the impact of university spin-offs considering several dimensions. On the other side the least explored dimensions include the analysis of the founders' background, and the establishment of public policies to support the activities of university spin-offs.
2018
Autores
Silva, APD; Filzmoser, P; Brito, P;
Publicação
ADVANCES IN DATA ANALYSIS AND CLASSIFICATION
Abstract
A multivariate outlier detection method for interval data is proposed that makes use of a parametric approach to model the interval data. The trimmed maximum likelihood principle is adapted in order to robustly estimate the model parameters. A simulation study demonstrates the usefulness of the robust estimates for outlier detection, and new diagnostic plots allow gaining deeper insight into the structure of real world interval data.
2018
Autores
Sadeghi, P; Rebelo, RD; Ferreira, JS;
Publicação
COMPUTERS & INDUSTRIAL ENGINEERING
Abstract
This paper addresses new Mixed-model Assembly Line Balancing Problems (MALBP) in a real industrial context, the stitching systems of a footwear company. The work is part of large ongoing projects with this industry, and the main purposes are minimising the number of required workstations and smoothing the operators' workload. The company has invested in new flexible automated assembly systems, which accommodate dozens of workstations and many moving boxes. Footwear components are inside boxes (with various quantities) which can move from the warehouses to a convenient workstation or between any workstations (in any order). This is a significant and distinct feature of the MALBP, together with the fact that the assignment of different skilled operators and machines is achieved simultaneously. An optimisation model is developed, in part to facilitate the understanding of the situation and to solve small-size instances. Due to the complexity of the problems, we had to devise an approximate method, based on the Variable Neighbourhood Descent (VND) metaheuristic and integrating an adaptation of the Ranked Positional Weighted (RPW) method. The adapted RPW method is used to create initial feasible solutions, while preassigning special operators and machines. After choosing good initial solutions, VND is applied to improve their quality. The new contributed method, named as RPW-VNDbal, is tested with medium and large instances, in two distinct stitching systems. A Lower Bound of the objective function and Simulation contribute to evaluate the solutions and their practicability. The results implemented by the project team, show that the RPW-VNDbal method is fast enough and offers better solutions than those implemented by the experienced operation managers of the company.
2018
Autores
Milczarski, P; O'Reilly, D; Podlaski, K; Almeida, FL; Dowdall, S; Hlobaz, A; Bolaert, H; Lourenço, J;
Publicação
Proceedings of the 14th International Conference on ICT in Education, Research and Industrial Applications. Integration, Harmonization and Knowledge Transfer. Volume I: Main Conference, Kyiv, Ukraine, May 14-17, 2018.
Abstract
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