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Publications

Publications by CPES

2014

Minimum-time path following in highly redundant electric vehicles

Authors
De Castro, R; Tanelli, M; Araujo, RE; Savaresi, SM;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
Autonomous vehicles are becoming a reality that in the next future will most probably start populating everyday roads. Such vehicles can, on the one hand, increase safety through automated driving, and, on the other, be a means of transportation also for people with disabilities who cannot move alone on commercial cars. Within this class of vehicles, mechanical layouts that allow an actuator redundancy coupled with electric propulsion appear particularly interesting, as they make it possible to design motion controller that can optimally blend multiple objectives, both dynamic, safety and driver-oriented. This paper considers such setting and concentrates on the design of a path-following algorithm with minimum-time features, with the aim of combining performance and energy-oriented optimization of the vehicle motion. The effectiveness of the approach is assessed by means of simulation tests carried out on the CarSim vehicle simulation environment. © IFAC.

2014

Identifying Benefits Between the Integration of Electric Vehicles and Renewable Power Usage

Authors
Costa, IC; Rosa, M; Carvalho, L; Bremermann, L; Iria, J;

Publication
2014 IEEE 8TH INTERNATIONAL POWER ENGINEERING AND OPTIMIZATION CONFERENCE (PEOCO)

Abstract
The impact of large-scale Electric Vehicles (EVs) deployment in electric power systems is a current issue under study by the scientific community. The integration of this type of electric component requires robust planning solutions to mitigate possible consequences from such integration. This paper explores the quantification of the amount of renewable sources, namely wind and hydro power, which can be safely integrated into power systems in a scenario of a mass integration of EVs. The increase of renewable power in the generation portfolio is analyzed under the framework of generating system adequacy assessment considering several EVs deployment scenarios and an adequate charging strategy. The analysis is carried for the planning configurations of the Portuguese and Spanish generating systems and the results are focused on the potential benefits of EV integration in terms of hydro and wind power usage.

2014

Analysis of electricity market prices using multidimensional scaling

Authors
Azevedo, F; Machado, JT;

Publication
Mathematical Methods in Engineering

Abstract
This paper studies the impact of the energy upon electricity markets using Multidimensional Scaling (MDS). Data from major energy and electricity markets is considered. Several maps produced by MDS are presented and discussed revealing that this method is useful for understanding the correlation between them. Furthermore, theresults help electricity markets agents hedging against Market Clearing Price (MCP) volatility. © Springer Science+Business Media Dordrecht 2014.

2014

HarmoSim: A tool for harmonic distortion simulation and assessment of nonlinear loads

Authors
Baptista, J; Morais, R; Valente, A; Soares, S; Candeias, M; Reis, MJCS;

Publication
COMPUTER APPLICATIONS IN ENGINEERING EDUCATION

Abstract
Electrical power quality (PQ) is a crucial competitive and developing factor to all economic activities. The economic impact resulting from a bad PQ would be drastic on all consumers. Computers, uninterruptible and switched power supplies (UPS), and fluorescent lamps/tubes are examples of nonlinear loads that have the consumption of a nonsinusoidal current, which cause disturbances in the power supply system (that may be severe or not). This study discusses residential generic power circuitry analysis and simulation, under nonlinear loads, in connection with undergraduate electrical engineering education. It briefly reviews some of the basic techniques, and presents a software tool that has been found to be very useful in the context. The tool has an easy-to-use, friendly interface, and can be used to teach design techniques or as a laboratory support to study the applicability of known methods to real situations. The students can perform simulations with their own data on Microsoft (TM) Windows (R)-based platforms. (c) 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:340-348, 2014; View this article online at ; DOI

2014

Individualizing propofol dosage: a multivariate linear model approach

Authors
Rocha, C; Mendonca, T; Silva, ME;

Publication
JOURNAL OF CLINICAL MONITORING AND COMPUTING

Abstract
In the last decades propofol became established as an intravenous agent for the induction and maintenance of both sedation and general anesthesia procedures. In order to achieve the desired clinical effects appropriate infusion rate strategies must be designed. Moreover, it is important to avoid or minimize associated side effects namely adverse cardiorespiratory effects and delayed recovery. Nowadays, to attain these purposes the continuous propofol delivery is usually performed through target-controlled infusion (TCI) systems whose algorithms rely on pharmacokinetic and pharmacodynamic models. This work presents statistical models to estimate both the infusion rate and the bolus administration. The modeling strategy relies on multivariate linear models, based on patient characteristics such as age, height, weight and gender along with the desired target concentration. A clinical database collected with a RugLoopII device on 84 patients undergoing ultrasonographic endoscopy under sedation-analgesia with propofol and remifentanil is used to estimate the models (training set with 74 cases) and assess their performance (test set with 10 cases). The results obtained in the test set comprising a broad range of characteristics are satisfactory since the models are able to predict bolus, infusion rates and the effect-site concentrations comparable to those of TCI. Furthermore, comparisons of the effect-site concentrations for dosages predicted by the proposed Linear model and the Marsh model for the same target concentration is achieved using Schnider model and a factorial design on the factors (patients characteristics). The results indicate that the Linear model predicts a dosage profile that is faster in leading to an effect-site concentration closer to the desired target concentration.

2014

Definition of Distribution Network Tariffs Considering Distribution Generation and Demand Response

Authors
Soares, T; Faria, P; Vale, Z; Morais, H;

Publication
2014 IEEE PES T&D CONFERENCE AND EXPOSITION

Abstract
The use of distribution networks in the current scenario of high penetration of Distributed Generation (DG) is a problem of great importance. In the competitive environment of electricity markets and smart grids, Demand Response (DR) is also gaining notable impact with several benefits for the whole system. The work presented in this paper comprises a methodology able to define the cost allocation in distribution networks considering large integration of DG and DR resources. The proposed methodology is divided into three phases and it is based on an AC Optimal Power Flow (OPF) including the determination of topological distribution factors, and consequent application of the MW-mile method. The application of the proposed tariffs definition methodology is illustrated in a distribution network with 33 buses, 66 DG units, and 32 consumers with DR capacity.

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