2015
Authors
Paulo, J;
Publication
Abstract
2015
Authors
Osorio, GJ; Lujano Rojas, JM; Matias, JCO; Catalao, JPS;
Publication
ENERGY CONVERSION AND MANAGEMENT
Abstract
Optimal operation of power systems with high integration of renewable power sources has become difficult as a consequence of the random nature of some sources like wind energy and photovoltaic energy. Nowadays, this problem is solved using Monte Carlo Simulation (MCS) approach, which allows considering important statistical characteristics of wind and solar power production such as the correlation between consecutive observations, the diurnal profile of the forecasted power production, and the forecasting error. However, MCS method requires the analysis of a representative amount of trials, which is an intensive calculation task that increases considerably with the number of scenarios considered. In this paper, a model to the scheduling of power systems with significant renewable powergeneration based on scenario generation/reduction method, which establishes a proportional relationship between the number of scenarios and the computational time required to analyse them, is proposed. The methodology takes information from the analysis of each scenario separately to determine the probabilistic behaviour of each generator at each hour in the scheduling problem. Then, considering a determined significance level, the units to be committed are selected and the load dispatch is determined. The proposed technique was illustrated through a case study and the comparison with stochastic programming approach was carried out, concluding that the proposed methodology can provide an acceptable solution in a reduced computational time.
2015
Authors
Alvarez Mozos, M; Ferreira, F; Alonso Meijide, JM; Pinto, AA;
Publication
OPTIMIZATION
Abstract
In this paper, we characterize two power indices introduced in [1] using two different modifications of the monotonicity property first stated by [2]. The sets of properties are easily comparable among them and with previous characterizations of other power indices.
2015
Authors
Bini, A; Amaral, TF; Oliveira, BM; Carvalho, P; Teixeira, VH;
Publication
EUROPEAN JOURNAL OF CLINICAL NUTRITION
Abstract
[abstract]
2015
Authors
Facao, M; Carvalho, MI;
Publication
PHYSICAL REVIEW E
Abstract
We found two stationary solutions of the cubic complex Ginzburg-Landau equation (CGLE) with an additional term modeling the delayed Raman scattering. Both solutions propagate with nonzero velocity. The solution that has lower peak amplitude is the continuation of the chirped soliton of the cubic CGLE and is unstable in all the parameter space of existence. The other solution is stable for values of nonlinear gain below a certain threshold. The solutions were found using a shooting method to integrate the ordinary differential equation that results from the evolution equation through a change of variables, and their stability was studied using the Evans function method. Additional integration of the evolution equation revealed the basis of attraction of the stable solutions. Furthermore, we have investigated the existence and stability of the high amplitude branch of solutions in the presence of other higher order terms originating from complex Raman, self-steepening, and imaginary group velocity.
2015
Authors
Sousa, JP; Cunha, CR; Morais, EP; Gomes, JP;
Publication
INNOVATION MANAGEMENT AND SUSTAINABLE ECONOMIC COMPETITIVE ADVANTAGE: FROM REGIONAL DEVELOPMENT TO GLOBAL GROWTH, VOLS I - VI, 2015
Abstract
This paper presents the study of modeling a quality supplier management system, based on a particular case of a Portuguese company in the auto industry that supplies parts to the major automobile manufacturers. For this, a study of a practical case of Supplier Quality Management (SQM) that follow the ISTO/TS 16949 standard was done, to analyze the functioning of their processes. Finally, a model is proposed streamline and automate supplier performance management processes, with the aim of improving the efficiency throughout the supplier chain.
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