2014
Authors
Macedo, N; Cunha, A; Pacheco, H;
Publication
EDBT/ICDT Workshops
Abstract
The Query/View/Transformation Relations (QVT-R) standard for bidirectional model transformation is notorious for its underspecified semantics. When restricted to transformations between pairs of models, most of the ambiguities and omissions have been addressed in recent work. Nevertheless, the application of the QVT-R language is not restricted to that scenario, and similar issues remain unexplored for the multidirectional case (maintaining consistency between more than two models), that has been overlooked so far. In this paper we first discuss ambiguities and omissions in the QVT-R standard concerning the mutidirectional transformation scenario, and then propose a simple extension and formalization of the checking and enforcement semantics that clarifies some of them. We also discuss how such proposal could be implemented in our Echo bidirectional model transformation tool. Ours is just a small step towards making QVT-R a viable language for bidirectional transformation in realistic applications, and a considerable amount of basic research is still needed to fully accomplish that goal.
2014
Authors
Dashtbozorg, B; Mendonça, AM; Penas, S; Campilho, A;
Publication
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
Authors
Baboli, PT; Moghaddam, MP; Haghifam, MR; Shafie Khah, M; Catalao, JPS;
Publication
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
Authors
Pires, A; Chamine, HI; Piqueiro, F; Rocha, F;
Publication
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
Authors
Pandey, SK; Mohanty, SR; Kishor, N; Catalao, JPS;
Publication
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
Authors
Goncalves, R; Gomes, S; Martins, J; Marques, C;
Publication
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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