Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2015

Grigora S: A Low-Cost, High Performance Micromouse Kit

Authors
Valente, A; Salgado, P; Boaventura Cunha, J;

Publication
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL

Abstract
There is a need to attract students to science and engineering courses. Robotic contests are one of the most promising ways to attract students to the field of robotics and thereby to science and technology. Micromouse contest is one of promising contests where a small autonomous robot has to navigate its way through an unknown 16 x 16 cells maze. Since the design and construction of robots is interesting but difficult, this paper presents a high performance, low-cost robot kit for high school and university students participate on micromouse robot contests. This micromouse kit, developed at University of Tras-os-Montes and Alto Douro (UTAD), fits on a 10x8 cm rectangle and uses very small stepper motors allowing a maximum speed of about 4 m/s thus comparing to state-of-the-art micromice. The kit also incorporates a popular microcontroller hardware module (Arduino Leonardo) which facilitates all programming tasks.

2015

Modeling of Extremal Earthquakes

Authors
Brito, M; Cavalcante, L; Moreira Freitas, ACM;

Publication
MATHEMATICS OF ENERGY AND CLIMATE CHANGE

Abstract
Natural hazards, such as big earthquakes, affect the lives of thousands of people at all levels. Extreme-value analysis is an area of statistical analysis particularly concerned with the systematic study of extremes, providing an useful insight to fields where extreme values are probable to occur. The characterization of the extreme seismic activity is a fundamental basis for risk investigation and safety evaluation. Here we study large earthquakes in the scope of the Extreme Value Theory. We focus on the tails of the seismic moment distributions and we propose to estimate relevant parameters, like the tail index and high order quantiles using the geometric-type estimators. In this work we combine two approaches, namely an exploratory oriented analysis and an inferential study. The validity of the assumptions required are verified, and both geometric-type and Hill estimators are applied for the tail index and quantile estimation. A comparison between the estimators is performed, and their application to the considered problem is illustrated and discussed in the corresponding context.

2015

Uncertainty Characterization of Carrier-Based Demand Response in Smart Multi-Energy Systems

Authors
Neyestani, N; Damavandi, MY; Shafie Khah, M; Catalao, JPS; Chicco, G;

Publication
2015 IEEE 5TH INTERNATIONAL CONFERENCE ON POWER ENGINEERING, ENERGY AND ELECTRICAL DRIVES (POWERENG)

Abstract
The concept of Carrier-Based Demand Response (CBDR) programs in Smart Multi-Energy Systems (MES) is proposed in this paper. It is discussed that by establishing the bi-directional relation between multi-energy demand and MES through the penetration of multi-carrier device technologies, the opportunity of demand-side participation in system operation can be activated. In this paper, the external dependency caused by multi-carrier devices is employed as a demand response. The CBDR is introduced as the flexibility of end-use to change the conversion pattern of input carriers into required demand. As the CBDR program is influenced by energy carrier prices, upstream network obligations and also the customer's behavior, its uncertainty is effectively modeled in this paper. The results compare the difference between the stochastic and deterministic approaches to the problem and show the improved accuracy through the stochastic modeling. The role of those customers that are not taking part in CBDR program is also investigated.

2015

New control strategy for the weekly scheduling of insular power systems with a battery energy storage system

Authors
Osorio, GJ; Rodrigues, EMG; Lujano Rojas, JM; Matias, JCO; Catalao, JPS;

Publication
APPLIED ENERGY

Abstract
The increment in generation costs is one of the most important factors that characterizes the operation of insular power systems, and is related to the location of these systems and the type of fuel used to provide electricity. This situation motivates the integration of renewable generation at high rates, as well as energy storage systems (ESSs), to improve the utilization of these resources. In this paper, a new control strategy is presented for the day-ahead scheduling of insular power systems with a battery energy storage system. The method presented here incorporates the effects of the most relevant components such as thermal generators, wind power generation, power converter, charge controller and ESS, being integrated into the scheduling process of insular power systems as a new contribution to earlier studies. The results provided show a fuel saving of 2% and an improvement in the wind power use of 20%, which is significant.

2015

Unequal individual genetic algorithm with intelligent diversification for the lot-scheduling problem in integrated mills using multiple-paper machines

Authors
Furlan, M; Almada Lobo, B; Santos, M; Morabito, R;

Publication
COMPUTERS & OPERATIONS RESEARCH

Abstract
This paper addresses the lot-sizing and scheduling problem of pulp and paper mills involving multiple paper machines. The underlying multi-stage integrated production process considers the following critical units: continuous digester, intermediate stocks of pulp and liquor, multiple paper machines and a recovery line to treat by-products. This work presents a mixed integer programming (MIP) model to represent the problem, as well as a solution approach based on a customized genetic algorithm (GA) with an embedded residual linear programming model. Some GA tools are explored, including literature and new operators, a novel diversification process and other features. In particular, the diversification process uses a new allele frequency measure to change between diversification and intensification procedures. Computational results show the effectiveness of the method to solve relatively large instances of the single paper machine problem when compared to other single paper machine solution methods found in the literature. For multiple paper machine settings, in most runs the GA solutions are better than those obtained for the MIP model using an optimization software.

2015

Behavior analysis environments e-learning

Authors
Gonçalves, S; Carneiro, D; Fdez-Riverola, F; Novais, P;

Publication
EDMETIC

Abstract
The evaluation is a determining factor in developing successful strategies for learning. In a classroom context, the teacher can observe the behavior of students and identify different ways to facilitate the assessment without inducing stress, avoiding the negative consequences of this on the result of learning. However, in learning environments eLearning direct contact is impossible and, therefore, there should be alternative ways to provide both detection and prevention of stress during the evaluation. It is therefore appropriate stress analysis and identification of strategies for solving problems arising from its appearance. In this work, a stress analysis module for use is proposed for the online student assessment, which is capable of indicating to the teaching moments more propitious time to intervene and the contents that cause greater difficulties. In this way, the teacher can effectively assist students who need it most.

  • 2681
  • 4376