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Publicações

2013

Multi-Agent Systems as Automation Platform for Intelligent Energy Systems

Autores
Leitao, P; Vrba, P; Strasser, T;

Publicação
39TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2013)

Abstract
The large-scale integration of distributed energy resources into a complex cyber-physical system demands proper automation platforms for monitoring, control, optimization and reconfiguration, addressing intelligent energy systems. This paper discusses the use of multi-agent systems as a suitable solution to address this challenge by analyzing their benefits when applying them to the field of Smart Grids and surveying existing works and initiatives. The principles and use cases established in the MASGrid project illustrate the application of multi-agent technology in active power distribution systems.

2013

A comparative study between causal and non-causal algorithms for the energy management of hybrid storage systems

Autores
Pinto, C; De Castro, R; Araujo, RE;

Publicação
2013 15th European Conference on Power Electronics and Applications, EPE 2013

Abstract
This paper presents a comparative study between two non-causal algorithms for the energy management problem of electric vehicles, endowed with batteries and supercapacitors(SCs). Toward that goal, an optimization-based energy problem is formulated, which targets the minimization of the source's energy losses throughout a given driving cycle. This problem is solved, firstly, with the help of a fast (but locally optimal) non-linear programming solver; and, secondly, with a slow, but globally optimal, dynamic programming (DP) approach. Simulation results will demonstrate that, despite the different theoretical properties associated with these two solver approaches, both generate similar solutions. In the second part of the work, we will develop a filter-based energy management algorithm, i.e., employ batteries to provide the low-frequency content of the power demand, while SCs cover the high-frequency demand. Our approach builds on the idea of adapting the filter's time constant throughout the vehicle's journey, using, for that purpose, a fuzzy logic algorithm and the information of the state of the vehicle. In comparison with the traditional fixed time-constant approach, the simulation results show that under some conditions the adaptive time-constant algorithm has the potential to reduce the energy losses of the sources by up to 62%. © 2013 IEEE.

2013

Analysis of the quality of hospital information systems audit trails

Autores
Cruz Correia, R; Boldt, I; Lapao, L; Santos Pereira, C; Rodrigues, PP; Ferreira, AM; Freitas, A;

Publicação
BMC MEDICAL INFORMATICS AND DECISION MAKING

Abstract
Background: Audit Trails (AT) are fundamental to information security in order to guarantee access traceability but can also be used to improve Health information System's (HIS) quality namely to assess how they are used or misused. This paper aims at analysing the existence and quality of AT, describing scenarios in hospitals and making some recommendations to improve the quality of information. Methods: The responsibles of HIS for eight Portuguese hospitals were contacted in order to arrange an interview about the importance of AT and to collect audit trail data from their HIS. Five institutions agreed to participate in this study; four of them accepted to be interviewed, and four sent AT data. The interviews were performed in 2011 and audit trail data sent in 2011 and 2012. Each AT was evaluated and compared in relation to data quality standards, namely for completeness, comprehensibility, traceability among others. Only one of the AT had enough information for us to apply a consistency evaluation by modelling user behaviour. Results: The interviewees in these hospitals only knew a few AT (average of 1 AT per hospital in an estimate of 21 existing HIS), although they all recognize some advantages of analysing AT. Four hospitals sent a total of 7 AT - 2 from Radiology Information System (RIS), 2 from Picture Archiving and Communication System (PACS), 3 from Patient Records. Three of the AT were understandable and three of the AT were complete. The AT from the patient records are better structured and more complete than the RIS/PACS. Conclusions: Existing AT do not have enough quality to guarantee traceability or be used in HIS improvement. Its quality reflects the importance given to them by the CIO of healthcare institutions. Existing standards (e.g. ASTM: E2147, ISO/TS 18308: 2004, ISO/IEC 27001: 2006) are still not broadly used in Portugal.

2013

Generalizing determinization from automata to coalgebras

Autores
Silva, Alexandra; Bonchi, Filippo; Bonsangue, MarcelloM.; Rutten, JanJ.M.M.;

Publicação
Logical Methods in Computer Science

Abstract

2013

Exploring the Stationary Wavelet Transform Detail Coefficients for Detection and Identification of the S1 and S2 Heart Sounds

Autores
Marques, N; Almeida, R; Rocha, AP; Coimbra, M;

Publicação
2013 COMPUTING IN CARDIOLOGY CONFERENCE (CINC)

Abstract
Most work done in Heart Sound Segmentation approaches use a threshold-based approach to correctly identify S1 and S2 segments in a given signal. We propose a new method that uses the Stationary Wavelet Transform to segment the signal and hierarchical clustering to distinguish the S1 and S2 heart sound from noise. This approach was tested in the Classifying Heart Sounds PASCAL Challenge datasets and achieved better results than the winning approach of this contest, with a total error redcution of 21% and 43% for Digiscope and iStethoscope in test sets, respectively.

2013

A Collaborative Planning Approach for Non-hierarchical Production Networks

Autores
Almeida, R; Toscano, C; Azevedo, AL; Carneiro, LM;

Publicação
Intelligent Non-hierarchical Manufacturing Networks

Abstract
This chapter presents an innovative collaborative planning (CP) approach for non-hierarchical production networks that enhances collaboration between partners in two different lifecycle phases of the virtual organizations (VOs). The first phase concerns the first planning iteration for the customer, and it basically defines the operations plan and a quotation for the customer, supported by a negotiation process between partners. The second phase concerns a detailed specification of the manufacturing operation and its planning. The chapter first presents a summary of the main trends and previous work concerning collaborative network (CN), governance models and approaches for CP. Next, it provides the requirements for the CP. The chapter ends with the methodology proposed for CP, considering two planning schemes and the evaluation of the quality of the solutions. © 2013 by John Wiley & Sons, Inc.

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