Open Access
ARTICLE
Che-Wun Hong1,2, Chia-Yun Tsai1
CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 79-94, 2010, DOI:10.3970/cmes.2010.067.079
Abstract This paper describes the quantum mechanical simulation on the photonic properties of group-III nitride clusters, whose bulk types are common materials for light emitting diodes (LEDs). In order to emit different colors of light using the same semiconductor materials, it is possible to vary the band gap by controlling the quantum dot sizes or doping a third atom theoretically. Density functional theory (DFT) calculations are performed to analyze a set of binary (GaN)n (3≤n≤32) and ternary InxGa1-xN (0≤x≤0.375) clusters to study their photonic characteristics. The ground state structures are optimized to calculate the binding energies using the time-independent DFT. Then… More >
Open Access
ARTICLE
Foued Derraz1, Laurent Peyrodie2, Antonio PINTI3, Abdelmalik Taleb-Ahmed3, Azzeddine Chikh4, Patrick Hautecoeur5
CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 95-118, 2010, DOI:10.3970/cmes.2010.067.095
Abstract We propose a new semi-automatic segmentation based Active Contour Model and statistic prior knowledge of Multiple Sclerosis (MS) Lesions in Regions Of Interest (RIO) within brain Magnetic Resonance Images(MRI). Reliable segmentation of MS lesion is important for at least three types of practical applications: pharmaceutical trails, making decision for drug treatment, patient follow-up. Manual segmentation of the MS lesions in brain MRI by well qualified experts is usually preferred. However, manual segmentation is hard to reproduce and can be highly cost and time consuming in the presence of large volume of MRI data. In other hand, automated segmentation methods are… More >
Open Access
ARTICLE
C. R. A. Silva1, H. P. Azikri de Deus1, G.E. Mantovani2, A.T. Beck3
CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 119-150, 2010, DOI:10.3970/cmes.2010.067.119
Abstract In this paper, the Askey-Wiener scheme and the Galerkin method are used to obtain approximate solutions to stochastic beam bending on Winkler foundation. The study addresses Euler-Bernoulli beams with uncertainty in the bending stiffness modulus and in the stiffness of the foundation. Uncertainties are represented by parameterized stochastic processes. The random behavior of beam response is modeled using the Askey-Wiener scheme. One contribution of the paper is a sketch of proof of existence and uniqueness of the solution to problems involving fourth order operators applied to random fields. From the approximate Galerkin solution, expected value and variance of beam displacement… More >
Open Access
ARTICLE
Chyanbin Hwu1,2, Mengchun Yu1
CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 151-174, 2010, DOI:10.3970/cmes.2010.067.151
Abstract A comprehensive finite element model incorporating the features of comprehensive wing model and finite element method is developed in this paper. This new model extends the applicability of comprehensive wing model from uniform composite wings to tapered composite wings. It preserves the simplicity of one-dimensional finite element but performs like three-dimensional finite element for wing structural analysis. To verify its accuracy and show its efficiency, this model which is applicable to the general dynamic analysis is reduced to two simple cases: static analysis and free vibration analysis. Based upon the reduction results for static and free vibration cases, several numerical… More >