Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2016

A bridgeless controlled rectifier for single split-phase systems

Authors
Marinus, NSML; Jacobina, CB; dos Santos, EC; Rocha, N; de Freitas, NB;

Publication
2016 IEEE Energy Conversion Congress and Exposition (ECCE)

Abstract

2016

The role of fire-suppression force in limiting the spread of extremely large forest fires in Portugal

Authors
Fernandes, PM; Pacheco, AP; Almeida, R; Claro, J;

Publication
EUROPEAN JOURNAL OF FOREST RESEARCH

Abstract
Large forest fires are notorious for their environmental and socio-economic impacts and are assigned a disproportionately high percentage of the fire management budget. This study addresses extremely large fires (ELF, C2500 ha) in Portugal (2003-2013). We analysed the effect of fire-suppression force variation on ELF duration, size and growth rate, versus the effect of the concomitant fire environment (namely fuel and weather) conditions. ELF occurred in highly flammable landscapes and typically were impelled by extreme fire weather conditions. Allocation of suppression resources (normalized per unit of burned area or perimeter length) was disparate among fires, suggesting inadequate incident management. Fire-suppression effort did not affect time to containment modelled by survival analysis. Regression tree analysis indicated ELF spread to be negatively affected by higher fire-suppression resourcing, less severe fire weather, lower time to containment and higher presence of <9-year-old fuels, by decreasing order of importance; regional variability was relevant. Fire environment-to-fire suppression ratios of influence were 3: 1 for fire size and 1: 1 for fire growth rate, respectively, explaining 76 and 60 % of the existing variability. Results highlight the opportunistic nature of large-fire containment. To minimize the area burned by ELF, management and operational improvements leading to faster containment are recommended, rather than higher fire-suppression resourcing; more effective identification and exploration of containment opportunities are preferable to the accumulation of suppression resources.

2016

A Lock-Free Hash Trie Design for Concurrent Tabled Logic Programs

Authors
Areias, M; Rocha, R;

Publication
INTERNATIONAL JOURNAL OF PARALLEL PROGRAMMING

Abstract
Tabling is an implementation technique that improves the declarativeness and expressiveness of Prolog systems in dealing with recursion and redundant sub-computations. A critical component in the design of a concurrent tabling system is the implementation of the table space. One of the most successful proposals for representing tables is based on a two-level trie data structure, where one trie level stores the tabled subgoal calls and the other stores the computed answers. In previous work, we have presented a sophisticated lock-free design where both levels of the tries where shared among threads in a concurrent environment. To implement lock-freedom we used the CAS atomic instruction that nowadays is widely found on many common architectures. CAS reduces the granularity of the synchronization when threads access concurrent areas, but still suffers from problems such as false sharing or cache memory effects. In this work, we present a simpler and efficient lock-free design based on hash tries that minimizes these problems by dispersing the concurrent areas as much as possible. Experimental results in the Yap Prolog system show that our new lock-free design can effectively reduce the execution time and scales better than previous designs.

2016

Quality of Life Assessment: Estimation based on Rasch model

Authors
Goncalves, J; Reis, LP; Faria, BM; Carvalho, V; Abreu, C;

Publication
2016 11TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
Continuous assessment of the quality of health-related life (HRQoL) of patients is an important aspect of health and gives rise to several readings. On one hand, the enormous amount of information that is generated allows the extraction of knowledge with great accuracy concerning the disease, the treatments and the impact it has on society, on the other hand, this continuous monitoring allows effective control and one timely intervention on the patient. The QoLIS platform has a set of characteristics advantageous over other, including the wide range of analyses that can be made from the results that it provides. However, the complexity of the calculus evolved on the models used, combined with the number of data processing, hamper its use in real time, hindering their use in the context of a medical appointment. Whereas the use of evaluation of quality of life (QoL) in the context of a appointment is an added value for everyone involved, it was necessary to develop and implement, on the QoLIS, a strategy for determining the value of QoL, by estimate, based on Rasch model (in order to provide the same set of responses) and whose response time allows its effective use

2016

Risk constrained offering strategy of wind power producers considering Intraday Demand Response Exchange

Authors
Heydarian-Forushani, E; Parsa Moghaddam, M; Sheikh-El-Eslami, MK; Shafie-khah, M; Catalao, J;

Publication
2016 IEEE/PES Transmission and Distribution Conference and Exposition (T&D)

Abstract

2016

Social Network Analysis and the Study of University Industry Relations

Authors
Romero, F; Costa, E;

Publication
PROCEEDINGS OF THE 11TH EUROPEAN CONFERENCE ON INNOVATION AND ENTREPRENEURSHIP

Abstract
The aim of this work is to give an overview on the development of theoretical concepts and methodological approaches to investigate innovation networks, in particular the use of social network analysis in the study of university industry relations. The structure of networks can be analysed through the lens of Social Network Analysis. This methodological approach is described and its fundamental concepts are presented. The paper then reviews the applications of this approach on the study of university industry relations. These relations can be considered as an innovation network, in the sense that the interactions established by its participants have more or less defined innovation goals. Different structures in the relations may result in different innovation outcomes, and the use of SNA may be particularly useful to understand differential outcomes. It is thus important to take stock of the knowledge concerning the efforts that have been made to probe the complex phenomena of university industry relations and, in particular, how approaches based on social network analysis have been used to understand it. This work is based on a review of available literature on the topics. The paper aims at systematizing the information and knowledge related to the application of SNA on university industry networks, highlighting the main research pathways, the main conclusions and pointing possible future research questions.

  • 2228
  • 4078