SangWook Han¹, JungYeon Seo¹, Dae-Young Kim², SeokHoon Kim³, HwaMin Lee^3,*

CMC-Computers, Materials & Continua, Vol.59, No.3, pp. 697-711, 2019, DOI:10.32604/cmc.2019.06071

Abstract Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human health. But there are too few fine dust measuring stations and the installation cost of fine dust measuring station is very expensive. In this paper, we propose Cloud-based air pollution information system using R. To measure fine dust, we have developed an inexpensive measuring device and studied the technique to accurately measure the concentration of fine dust at the user’s location. And we have developed the smartphone application to provide air pollution information. In our system, we… More >

Yuqing Yang^1,2, Dequn Zhou^1,*, Xiaojiang Yang^1,3,4

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 625-633, 2019, DOI:10.32604/cmc.2019.05246

Abstract Massive open online courses (MOOC) have recently gained worldwide attention in the field of education. The manner of MOOC provides a new option for learning various kinds of knowledge. A mass of data miming algorithms have been proposed to analyze the learner’s characteristics and classify the learners into different groups. However, most current algorithms mainly focus on the final grade of the learners, which may result in an improper classification. To overcome the shortages of the existing algorithms, a novel multi-feature weighting based K-means (MFWK-means) algorithm is proposed in this paper. Correlations between the widely used feature grade and other… More >

Guojian Li¹, Qiang Wang¹, Yongze Cao¹, Kai Wang¹, Jiaojiao Du¹, Jicheng He¹

CMC-Computers, Materials & Continua, Vol.30, No.3, pp. 195-206, 2012, DOI:10.3970/cmc.2012.030.195

Abstract This paper studies the influence of Ag atomic segregation on the structural evolutions of the mixed (PdAg)₃₀₉ clusters during the heating processes by using molecular dynamics with a general embedded atom method. The results show that the Ag atomic segregation makes the cluster exhibit a segregate-melting stage in which the energy does not monotonic increase with the increase of temperature. In this stage, the cluster first transforms to form a disorder structure from the initial icosahedron and then a decahedron. By comparing with the cases in the pure Pd₃₀₉, Ag₃₀₉, and core-shell (PdAg)₃₀₉, it is found that the icosahedral-decahedral transformation… More >

Cheng-Hung San¹, Chuang-Pin Chiu¹, Che-Wun Hong^1,2

CMC-Computers, Materials & Continua, Vol.26, No.3, pp. 167-186, 2011, DOI:10.3970/cmc.2011.026.167

Abstract An improvement in the catalytic process of oxygen reduction reactions is of prime importance for further progress in low temperature fuel cell performance. This paper intends to investigate this problem from a fundamental quantum mechanics viewpoint. For this purpose, a hybrid density functional theory is employed to analyze the catalytic mechanism of the oxygen reduction at the fuel cell cathode. Major steps in the oxygen reduction that include the oxygen adsorption on solid metal clusters (e.g. Cu and Pt) and complete four proton transfer steps are simulated. Proton transfer processes from hydroniums to the adsorbed oxygen molecules to produce water… More >

Sunil Kr. Jha¹, Zulfiqar Ahmad²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 443-459, 2017, DOI:10.3970/cmes.2017.113.443

Abstract Microbial population and enzyme activities are the significant indicators of soil strength. Soil microbial dynamics characterize microbial population and enzyme activities. The present study explores the development of efficient predictive modeling systems for the estimation of specific soil microbial dynamics, like rock phosphate solubilization, bacterial population, and ACC-deaminase activity. More specifically, optimized subtractive clustering (SC) and Wang and Mendel's (WM) fuzzy inference systems (FIS) have been implemented with the objective to achieve the best estimation accuracy of microbial dynamics. Experimental measurements were performed using controlled pot experiment using minimal salt media with rock phosphate as sole carbon source inoculated with… More >

R.D. Phillips¹, M.S. Hossain¹, L.T. Watson^1,2, R.H. Wynne³, Naren Ramakrishnan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.2, pp. 175-197, 2014, DOI:10.3970/cmes.2014.097.175

Abstract Clusters, typically mined by modeling locality of attribute spaces, are often evaluated for their ability to demonstrate ‘enrichment’ of categorical features. A cluster enrichment procedure evaluates the membership of a cluster for significant representation in predefined categories of interest. While classical enrichment procedures assume a hard clustering definition, this paper introduces a new statistical test that computes enrichments for soft clusters. Application of the new test to several scientific datasets is given. More >

J.E. Lee¹and S.J. Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.2, pp. 93-112, 2012, DOI:10.3970/cmes.2012.086.093

Abstract As the option trading nowadays has become popular, it is important to simulate efficiently large amounts of option pricings. The purpose of this paper is to show valuations of large amount of options, using network distribute computing resources. We valuated 108 options simultaneously on the self-made cluster computer system which is very inexpensive, compared to the supercomputer or the GPU adopting system. For the numerical valuations of options, we developed the option pricing software to solve the Black-Scholes partial differential equation by the finite element method. This yielded accurate values of options and the Greeks with reasonable computational times. This… More >

Zone-Ching Lin¹, Chen-Hsing Cheng²

CMES-Computer Modeling in Engineering & Sciences, Vol.68, No.1, pp. 25-54, 2010, DOI:10.3970/cmes.2010.068.025

Abstract This study considers loadings on the multi-layer web frame structure and uses a novel method of the modified analytical hierarchy process (AHP) combined with modified theory of inventive problem solving (TRIZ) clustering to perform the creative structure design. The engineering knowledge of multi-layer web frame structure comprises such issues as vibration, yielding and buckling strength. Using the modified AHP, this study firstly applies the ratios of occurrence numbers of related keywords on different hierarchies to analyze the techniques and functions of multi-layer web frame structure, and finds out the priority order of feasible design decisions. Furthermore, this study also proposes… More >

Jong Keun Moon¹, Seung Jo Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.3, pp. 239-264, 2010, DOI:10.3970/cmes.2010.067.239

Abstract Large structural problems with high precision and complexity require a high-performance computation using the efficient parallel algorithm. The purpose of this paper is to present the parallel performance of thermal-structural coupled analysis tested on a parallel cluster system. In the coupled analysis, the heat transfer analysis is carried out, and then the structural analysis is performed based on temperature distribution. For the automatic and efficient connection of two parallel analysis modules, the several communication patterns were studied. The parallel performance was demonstrated for the sample and the real application problems, such as a laminated composite material by the DNS(Direct Numerical… More >

Che-Wun Hong^1,2, 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 In_xGa_1-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 >