Home  About us  Contact
 

Efficiency Calculations (efficiency + calculation)

Distribution by Scientific Domains
Mathematics and Statistics50%

Selected Abstracts

Quantum and conversion efficiency calculation of AlGaAs/GaAs multiple quantum well solar cells

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 9 2005
J. C. Rimada
Abstract The quantum well solar cell (QWSC) is a novel device that has been proposed by Barnham and co-workers at Imperial College London. In this work, the quantum efficiency for AlGaAs/GaAs QWSC has been calculated and compared with available data from the group at Imperial College London. Quantum efficiency calculations will be presented and compared with experimental data for several AlGaAs/GaAs QWSC, obtaining good agreement. The photocurrent then is calculated from the quantum efficiency calculations and included in the J(V) relation to optimize the efficiency of AlGaAs/GaAs QWSC. It also shows that for a range of quantum well widths and barrier bandgaps the conversion efficiencies of the quantum well solar cell are higher than the corresponding homogeneous p,i,n solar cell. Our results give a broad representation of quantum well solar cell operation, and provide a profitable guide for designing and interpreting the performance characteristics of AlGaAs/GaAs QWSCs. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

On blest's measure of rank correlation

THE CANADIAN JOURNAL OF STATISTICS, Issue 1 2003
Christian Genest
Abstract Blest (2000) proposed a new nonparametric measure of correlation between two random variables. His coefficient, which is dissymmetric in its arguments, emphasizes discrepancies observed among the first ranks in the orderings induced by the variables. The authors derive the limiting distribution of Blest's index and suggest symmetric variants whose merits as statistics for testing independence are explored using asymptotic relative efficiency calculations and Monte Carlo simulations. Blest (2000) a proposé une nouvelle mesure non paramétrique de corrélation entre deux variables aléatoires. Son coefficient, qui est asymétrique en ses arguments, met l'accent sur les écarts observés dans les premiers rangs des classements induits par les aléas. Les auteurs déterminent la loi limite de l'indice de Biest et en suggèrent des variantes symétriques dont ils explorent les mérites en tant que statistiques de tests d'indépendance au moyen de calculs d'efficacité relative asymptotique et d'une étude de Monte-Carlo. [source]

A Note on Estimating Crude Odds Ratios in Case,Control Studies with Differentially Misclassified Exposure

BIOMETRICS, Issue 4 2002
Robert H. Lyles
Summary. Morrissey and Spiegelman (1999, Biometrics55, 338,344) provided a comparative study of adjustment methods for exposure misclassification in case-control studies equipped with an internal validation sample. In addition to the maximum likelihood (ML) approach, they considered two intuitive procedures based on proposals in the literature. Despite appealing ease of computation associated with the latter two methods, efficiency calculations suggested that ML was often to be recommended for the analyst with access to a numerical routine to facilitate it. Here, a reparameterization of the likelihood reveals that one of the intuitive approaches, the inverse matrix method, is in fact ML under differential misclassification. This correction is intended to alert readers to the existence of a simple closed-form ML estimator for the odds ratio in this setting so that they may avoid assuming that a commercially inaccessible optimization routine must be sought to implement ML. [source]