• Journal of Ocean Engineering and Technology
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• v.10 no.2
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• pp.61-68
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• 1996

Weibull distribution function is applied very successfully to the strength of brittle materials such as ceramics and the weakest link model is applied to explain the ovents. This paper deals with the effect of specimen size on the strength of ceramics. The values of tensile strength were calculated by the Monte-Calro simuation. The tensile strength obtained was plotted on Weibull probabillity papers and represented by the 3-parameter Weibull distribution. The strength distribution function was compared with the theoretical weibull distribution. As a result, it was found that the Weibull shape parameter was changed due to the size and there was a possibility of a false indication as if the weakest link model holds good. We should be very careful when we apply the Weibull statistics to estimate the strength of products.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.729-739
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• 2016

Kruskal and Wallis (1952) proposed a nonparametric method to test the differences between more than three independent treatments. This procedure uses rank in mixed sample combined with more than three unlike populations. This paper proposes a the new procedure based on joint placements for a one-way layout as extension of the joint placements described in Chung and Kim (2007). A Monte Carlo simulation study is adapted to compare the power of the proposed method with previous methods.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1406-1418
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• 2002

The direct simulation Monte Carlo(DSMC) method is employed to calculate the etch rate on Al wafer. The etchant is assumed to be Cl$_2$. The etching process of an Al wafer in a helicon plasma etcher is examined by simulating molecular collisions of reactant and product. The flow field inside a plasma etch reactor is also simulated by the DSMC method fur a chlorine feed gas flow. The surface reaction on the Al wafer is simply modelled by one-step reaction: 3C1$_2$+2Allongrightarrow1 2AIC1$_3$. The gas flow inside the reactor is compared for six different nozzle locations. It is found that the flow field inside the reactor is affected by the nozzle locations. The Cl$_2$ number density on the wafer decreases as the nozzle location moves toward the side of the reactor. Also, the present numerical results show that the nozzle location 1, which is at the top of the reactor chamber, produces a higher etch rate.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.148-155
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• 2015

The Levenberg-Marquardt method is a well known solution about the least square problem. However, in a Target Motion Analysis(TMA) application most of researches have used the Gauss-Newton method as a batch estimator, which of inverse matrix calculation may causes instability problem. In this paper, Levenberg-Marquardt method is applied to TMA problem to prevent its divergence. In experiment, its performance is compared with Gauss-Newton in domain of range, course and speed. Monte Carlo simulation reveals the convergence time and reliability of the TMA based on Levenberg-Marquardt.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.169-176
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• 2020

Interventional radiology is performed under real-time fluoroscopy, and patients are exposed to a wide range of exposures for a long period of time depending on the examination and procedure. However, studies on radiation protection for patients during an intervention are insufficient. This study aims to evaluate the doses exposed during the intervention and the applicability of 3D printing materials. The organ dose for each intervention site was evaluated using a monte carlo simulatio. Also, the dose reduction effect of the critical organs was calculated when using a shielding device using 3D printing materials. As a result, the organ dose distribution for each intervention site showed a lower dose distribution for organs located far from the x-ray tube. It was analyzed that the influence of scattered rays was higher in the superficial organs of the back of the human body where x-rays were incident. The dose reduction effect on the critical organ using the 3D printing shield showed the highest testis among the gonads, and in the case of other organs, the dose reduction effect gradually decreased in the order of the eye, thyroid, breast, and ovary. Accordingly, it is judged that the 3D printed shield will be sufficiently usable as a shielding device for the radiation protection of critical organs.

• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.21-26
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• 2007

This study is performed to evaluate the dose rate and to analyze the dose distribution of the gamma irradiation facility (IR-221) by using a Monte Calro simulation, which is helpful of upgrading the radiation processing qualification. Monte Cairo simulation is performed by MCNP4B code. Dose rates were measured at total 369 points with alanine dosimeters to compare the calculation results and the measurements data. The results have shown that the MCNP4B code is very useful to determine the dose distribution of the IR-221 gamma irradiation facility, as the calculation dose rate is within about ${\pm}5%$ of the measurement data. Dosimetry about the gamma irradiation facility usually needs enormous manpower and time. However Monte Cairo calculation method can reduce the tedious dosimetry jobs and improve the irradiation processing qualification, which will probably contribute to obtain the reliability of the irradiation products.

• Journal of Korean Society for Quality Management
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• v.25 no.3
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• pp.22-38
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• 1997

In a traditional sequential acceptance sampling plan, it is assumed that the sampled items are independent each other. In this paper, stochastically dependent sequential acceptance sampling plans are dealt when there exists dependency between sampled items. Monte-Calro algorithm is used to find the acceptance and rejection probabilities of a lot. The number of defectives for the test to be accepted and rejected in probability ratio sequential test can be found by using these probabilities. The formula for measures of performance of these sampling plans is developed. Type I and II error probabilities are estimated by simulation. This research can be a, pp.ied to sequential sampling procedures in place of control charts where there is a recognized and necessary dependency during the production processes. Also, dependent multiple acceptance sampling plans can be derived by extending this sequential sampling procedure. As a numerical example, a Markov dependent process model is given, and the characteristics of the sampling plans are examined according to the change of the dependency factor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.523-526
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• 2011

This is concerned with the structural reliability analysis(RA) considering uncertainties in material properties. This method is performed by the stochastic process using Kriging with calculating the distribution of probability and equation of limit state for saving calculated and analyzed time. The proposed methodology is applied to the rocket motor case and compared with monte-calro simulation in efficiency and accuracy of this process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.154-159
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• 1997

This paper describes the electron transport characteristic in SiH$_4$ gas calculated for range of E/N values from 0.5~300(Td) by the Monte Calro simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained for TOF method. The results gained that the value of an electron swarm parameter such as the electron drift velocity, the electron ionization coefficients longitudinal and transverse diffusion coefficients, characteristics energy agree with thee experimental and theoretical for a range of E/N. The electron energy distributions function were analysed in monosilane at EN : 30, 50(Td) for a case of equilibrium region in the mean electron energy. The validity of the results obtained has been confirmed by a TOF method.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.233-238
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• 2003

Goodness of fit test statistics based on the information discrepancy have been shown to perform very well (Vasicek 1976, Dudewicz and van der Meulen 1981, Chandra et al 1982, Gohkale 1983, Arizona and Ohta 1989, Ebrahimi et al 1992, etc). Although the test is well defined for the non-censored case, censored case has not been discussed in the literature. Therefore we consider a goodness of fit test based on the partial Kullback-Leibler(KL) information with the type II censored data. We derive the partial KL information of the null distribution function and a nonparametric distribution function, and establish a goodness of fit test statistic. We consider the exponential and normal distributions and made Monte Calro simulations to compare the test statistics with some existing tests.