Abstract

Abstract

Abstract
The era of mass customization of goods forces manufacturing systems to promote agility, flexibility and responsiveness, leading to complex and unpredictable systems. Such challenges have an impact in terms of the system responsiveness and adaptation, production costs, product quality, etc. In order to improve those aspects, some flexible control manufacturing paradigms were proposed offering elasticity to change available skills and provide new services. However, the understanding of when and how to (self-) reconfigure the system aiming to perform a fast changeover, is a crucial issue. This work proposes a self-organizing multi-agent system approach for an efficient and on the fly reconfiguration of services in the manufacturing domain. Besides self-organizing techniques, other dimensions, e.g., "social-based" trust and QoS metrics, are used to ensure a constant QoS in an agile production system. The insertion of intelligent agents facilitates the improvement of strategies that perform the service reconfiguration, and in addition, permits to understand when and how self-reconfiguration takes place in order to allow a continuous improvement of the system performance. Additionally, this work addresses solutions for real industrial applications, being aligned with some characteristics of the Industrie 4.0 initiative, namely the distributed intelligence and self-* methods, e.g. self-adaptation, self-organization and self-configuration.

Abstract

Abstract
The Biblioteca Digital de Arte (BDArt) Digital Library hosted by the Thematic Repository at the University of Porto (Repositório Tem ático da U.Porto) aggregates documents from the library and the archive collections belonging to the Fine Arts School of the University of Porto (Faculdade de Belas Artes da U.Porto). This school has a museum collection containing a significant set of world-class ob- jects managed with distinct processes and tools from those currently used in libraries and archives elsewhere. Interoperability between the collections of the archive, the library, and the museum is necessary because many works allocated to different collections are closely related and can only be seen as a whole by cross-collection search functionalities. The goal of this work, the first of its kind to be developed at the University of Porto (U. Porto), is to integrate the museum collection with archives and library collections in the repository and to use an open-source technology (DSpace). Our experiment involved the selection of appropriate representations of the objects and the definition of a metadata crosswalk between the original metadata standards and qualified Dublin Core. As a result, we created the BDA Museum Collection as a BDArt subcom- munity using an XML export procedure that we expect to be helpful in future developments of other museum collections in the Thematic Repository at U.Porto. © Isabel Barroso, Nadia Hartmann, and Cristina Ribeiro.

Abstract
This study develops a framework to provide insights regarding the performance of the farms of an energy player in the Portuguese wind sector. The focus of the wind farm performance assessment is on the operating stage which corresponds to the electrical energy generation process, during 2010 and 2011. In a first stage, Data Envelopment Analysis is used to measure the efficiency of wind farms in generating electrical energy from the resources available and non-discretionary variables. This analysis enables the identification of the best practices of the efficient farms which can be emulated by inefficient ones. In a second stage, changes in wind farms productivity are investigated using Malmquist index. Bootstrap procedures are applied to obtain statistical inference on the efficiency estimates. We conclude that almost all farms decreased overall productivity levels, mainly due to the decline in the productivity levels of the frontier, which is in accordance with the decrease in wind availability observed in 2011.