2014
Autores
Dashtbozorg, B; Mendonça, AM; Penas, S; Campilho, A;
Publicação
2014 36TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)
Abstract
This paper introduces RetinaCAD, a system, for the fast, reliable and automatic measurement of the Central Retinal Arteriolar Equivalent (CRAE), the Central Retinal Venular Equivalent (CRVE), and the Arteriolar-to-Venular Ratio (AVR) values, as well as several geometrical features of the retinal vasculature. RetinaCAD identifies important landmarks in the retina, such as the blood vessels and optic disc, and performs artery/vein classification and vessel width measurement. The estimation of the CRAE, CRVE and AVR values on 480 images from 120 subjects has shown a significant correlation between right and left eyes and also between images of same eye acquired with different camera fields of view. AVR estimation in retinal images of 54 subjects showed the lowest values in people with diabetes or high blood pressure thus demonstrating the potential of the system as a CAD tool for early detection and follow-up of diabetes, hypertension or cardiovascular pathologies.
2014
Autores
Baboli, PT; Moghaddam, MP; Haghifam, MR; Shafie Khah, M; Catalao, JPS;
Publicação
2014 POWER SYSTEMS COMPUTATION CONFERENCE (PSCC)
Abstract
In this paper, a new concept of serving flexible reliability (FR) is introduced in distribution network level. FR is defined as the ability of a grid to continue servicing the high priority customers in contingency states. Customers' priority is recognized based on their value of service reliability. Regarding this matter, the philosophy of designing a hybrid AC-DC microgrid is introduced with the ability of offering an alternative resource for each individual customer in contingency states. The analytical modeling of FR analysis besides the overall reliability analysis is proposed, and the new FR index of expected energy retrieved (EER) is introduced. The performance of the proposed hybrid microgrid in serving FR is demonstrated through a numerical study on modified distribution network for Bus-4 of Roy Billinton Test System (RBTS).
2014
Autores
Pinto, T; Ramos, S; Sousa, TM; Vale, Z;
Publicação
2014 IEEE SYMPOSIUM ON COMPUTATIONAL INTELLIGENCE IN DYNAMIC AND UNCERTAIN ENVIRONMENTS (CIDUE)
Abstract
Wind speed forecasting has been becoming an important field of research to support the electricity industry mainly due to the increasing use of distributed energy sources, largely based on renewable sources. This type of electricity generation is highly dependent on the weather conditions variability, particularly the variability of the wind speed. Therefore, accurate wind power forecasting models are required to the operation and planning of wind plants and power systems. A Support Vector Machines (SVM) model for short-term wind speed is proposed and its performance is evaluated and compared with several artificial neural network (ANN) based approaches. A case study based on a real database regarding 3 years for predicting wind speed at 5 minutes intervals is presented.
2014
Autores
Pires, A; Chamine, HI; Piqueiro, F; Rocha, F;
Publicação
MARINE GEORESOURCES & GEOTECHNOLOGY
Abstract
This work deals with the problem of assessing armourstone structures focusing on strengthening the combination of geo-marine techniques and geotechnical properties. The research has two main purposes: (i) to establish an integrative coastal geo-engineering approach for better assessment of the hydraulic structures; and (ii) to draw attention to the importance of quarry evaluation in order to improve armourstone quality and durability. Several studies have demonstrated the relevance of a holistic approach to coastal design issues. The suggested approach couples GIS-based mapping with geo-engineering techniques assessment along five pilot sectors of the Espinho coastal system in Northwestern Portugal. This investigation allowed us to propose zoning a coastal structure according to its degree of deterioration, geomechanical properties and geomaterial status. Replacement of the primary armour layer in only selected sections or components of the structure will reduce the cost of maintenance, repair and reinforcement work. All the gathered data about the preservation status of the armour layer and the quarry inventory have been compiled in a powerful GIS geo-database. The paper argues for the wider use of combination of coastal geo-engineering and GIS analysis in planning the monitoring and/or maintenance of marine works using armourstone.
2014
Autores
Pandey, SK; Mohanty, SR; Kishor, N; Catalao, JPS;
Publicação
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
Abstract
It is often necessary to investigate the output power against load demand in a system having distributed generation (DG) resources connected to the existing conventional power system. In this paper, the load frequency control (LFC) problem is presented using different optimization algorithms for two types of power system configurations: (i) hybrid configuration of thermal power system (TPS) integrated with DG, comprising wind turbine generators (WTGs), diesel engine generators (DEGs), fuel cells (FCs), aqua-electrolyzer (AE) and battery energy storage system (BESS); (ii) two area interconnected power system with DG connected in area-1. The inclusion of wind energy system in DG, having high variability in its output power, results into a challenging task for the realization of an effective controller design. This difficulty is further enhanced with random variation of load demand. The control scheme proposed in this paper is based on linear matrix inequalities (LMI) with its parameters tuned by particle swarm optimization (PSO), as a new contribution to earlier studies. The robustness of this controller is thoroughly demonstrated in the above hybrid power systems with different conditions of load disturbances, wind power and parameter variations.
2014
Autores
Goncalves, R; Gomes, S; Martins, J; Marques, C;
Publicação
PROCEEDINGS OF THE 2014 9TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2014)
Abstract
This work results from an exhaustive characterization of the practices of E-commerce through the use of a questionnaire to small and medium enterprises of Tras-os-Montes and Alto Douro in Portugal, seeking to identify and promote the use of this technology in order to obtain competitive advantages.
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