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Publications

2015

MASCEM: EPEX SPOT Day-Ahead market integration and simulation

Authors
Santos, G; Fernandes, R; Pinto, T; Praça, I; Vale, Z; Morais, H;

Publication
2015 18th International Conference on Intelligent System Application to Power Systems, ISAP 2015

Abstract
The energy sector restructuring process in industrialized countries had the aim of reducing electricity prices by increasing competitiveness, and facilitate the integration of distributed energy resources. However, the complexity in market players' interactions has increased, and new problems have emerged. Decision support tools that facilitate the study and comprehension of these markets became extremely useful, providing players with competitive advantage. MASCEM (Multi-Agent Simulator of Competitive Electricity Markets) arises in this context, modeling and simulating real electricity markets. It is crucial to MASCEM to have the ability to simulate as many market models and player types as possible, thus enhancing the ability to recreate the electricity markets reality in its maximum possible extent. This paper presents the EPEX Spot Day-Ahead market integration in MASCEM. EPEX Spot SE's mission is to lead European markets coupling in a single unified market, thus being crucial for the study of competitive electricity markets. © 2015 IEEE.

2015

Multi-component joint analysis of surface waves

Authors
Dal Moro, G; Marques Moura, RMM; Moustafa, SSR;

Publication
JOURNAL OF APPLIED GEOPHYSICS

Abstract
Propagation of surface waves can occur with complex energy distribution amongst the various modes. It is shown that even simple Vs (shear-wave velocity) profiles can generate velocity spectra that, because of a complex mode excitation, can be quite difficult to interpret in terms of modal dispersion curves. In some cases, Rayleigh waves show relevant differences depending on the considered component (radial or vertical) and the kind of source (vertical impact or explosive). Contrary to several simplistic assumptions often proposed, it is shown, both via synthetic and field datasets, that the fundamental mode of Rayleigh waves can be almost completely absent. This sort of evidence demonstrates the importance of a multi-component analysis capable of providing the necessary elements to properly interpret the data and adequately constrain the subsurface model. It is purposely shown, also through the sole use of horizontal geophones, how it can be possible to efficiently and quickly acquire both Love and Rayleigh (radial-component) waves. The presented field dataset reports a case where Rayleigh waves (both their vertical and radial components) appear largely dominated by higher modes with little or no evidence of the fundamental mode. The joint inversion of the radial and vertical components of Rayleigh waves jointly with Love waves is performed by adopting a multi-objective inversion scheme based on the computation of synthetic seismograms for the three considered components and the minimization of the whole velocity spectra misfits (Full Velocity Spectra - FVS - inversion). Such a FVS multi-component joint inversion can better handle complex velocity spectra thus providing a more robust subsurface model not affected by erroneous velocity spectra interpretations and non-uniqueness of the solution.

2015

Explanatory Information Analysis for Day-Ahead Price Forecasting in the Iberian Electricity Market

Authors
Monteiro, C; Fernandez Jimenez, LA; Ramirez Rosado, IJ;

Publication
ENERGIES

Abstract
This paper presents the analysis of the importance of a set of explanatory (input) variables for the day-ahead price forecast in the Iberian Electricity Market (MIBEL). The available input variables include extensive hourly time series records of weather forecasts, previous prices, and regional aggregation of power generations and power demands. The paper presents the comparisons of the forecasting results achieved with a model which includes all these available input variables (EMPF model) with respect to those obtained by other forecasting models containing a reduced set of input variables. These comparisons identify the most important variables for forecasting purposes. In addition, a novel Reference Explanatory Model for Price Estimations (REMPE) that achieves hourly price estimations by using actual power generations and power demands of such day is described in the paper, which offers the lowest limit for the forecasting error of the EMPF model. All the models have been implemented using the same technique (artificial neural networks) and have been satisfactorily applied to the real-world case study of the Iberian Electricity Market (MIBEL). The relative importance of each explanatory variable is identified for the day-ahead price forecasts in the MIBEL. The comparisons also allow outlining guidelines of the value of the different types of input information.

2015

Fault Detection in C Programs using Monitoring of Range Values: Preliminary Results

Authors
Pinto, P; Abreu, R; Cardoso, JMP;

Publication
CoRR

Abstract

2015

Benchmarking clinical practice in surgery: looking beyond traditional mortality rates

Authors
Castro, RAS; Oliveira, PN; Portela, CS; Camanho, AS; Melo, JQE;

Publication
HEALTH CARE MANAGEMENT SCIENCE

Abstract
This paper proposes two new measures to assess performance of surgical practice based on observed mortality: reliability, measured as the area under the ROC curve and a living score, the sum of individual risk among surviving patients, divided by the total number of patients. A Monte Carlo simulation of surgeons' practice was used for conceptual validation and an analysis of a real-world hospital department was used for managerial validation. We modelled surgical practice as a bivariate distribution function of risk and final state. We sampled 250 distributions, varying the maximum risk each surgeon faced, the distribution of risk among dead patients, the mortality rate and the number of surgeries performed yearly. We applied the measures developed to a Portuguese cardiothoracic department. We found that the joint use of the reliability and living score measures overcomes the limitations of risk adjustedmortality rates, as it enables a different valuation of deaths, according to their risk levels. Reliability favours surgeons with casualties, predominantly, in high values of risk and penalizes surgeons with deaths in relatively low levels of risk. The living score is positively influenced by the maximum risk for which a surgeon yields surviving patients. These measures enable a deeper understanding of surgical practice and, as risk adjusted mortality rates, they rely only on mortality and risk scores data. The case study revealed that the performance of the department analysed could be improved with enhanced policies of risk management, involving the assignment of surgeries based on surgeon's reliability and living score.

2015

Design and Implementation of a Biologically Inspired Swimming Robot An EPS@ISEP 2014 Spring Project

Authors
Ishii, A; Heibeck, M; Blazejewski, M; Nybjörk, R; Duarte, AJ; Malheiro, B; Ribeiro, C; Ferreira, F; Silva, MF; Ferreira, P; Guedes, P;

Publication
THIRD INTERNATIONAL CONFERENCE ON TECHNOLOGICAL ECOSYSTEMS FOR ENHANCING MULTICULTURALITY, PROCEEDINGS TEEM'15

Abstract
This paper presents the development of a fish-like robot called Bro-Fish. Bro-Fish aims to be an educational toy dedicated to teaching mechanics, programming and the physics of floating objects to youngsters. The underlying intention is to awaken the interest of children for technology, especially biomimetic (biologically inspired) approaches, in order to promote sustainability and raise the level of ecological awareness. The main focus of this project was to create a robot with carangiform locomotion and controllable swimming, providing the opportunity to customize parts and experiment with the physics of floating objects. Therefore, the locomotion principles of fishes and mechanisms developed in related projects were analysed. Inspired by this background knowledge, a prototype was designed and implemented. The main achievement is the new tail mechanism that propels the robot. The tail resembles the undulation motion of fish bodies and is actuated in an innovative way, triggered by an elegant movement of a rotating helicoidal. First experimental tests revealed the potential of the proposed methodology to effectively generate forward propulsion.

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