• Communications for Statistical Applications and Methods
• /
• v.20 no.6
• /
• pp.475-480
• /
• 2013

The surplus process in a risk model is stochastically analyzed. We obtain the characteristic function of the level of the surplus at a finite time, by establishing and solving an integro-differential equation for the distribution function of the surplus. The characteristic function of the stationary distribution of the surplus is also obtained by assuming that an investment of the surplus is made to other business when the surplus reaches a sufficient level. As a consequence, we obtain the first and second moments of the surplus both at a finite time and in an infinite horizon (in the long-run).

• Proceedings of the Korean Reliability Society Conference
• /
• 2004.07a
• /
• pp.167-175
• /
• 2004

A nonparametric procedure is proposed to test the exponentiality against the hypothesis that one life distribution has a greater residual life times than the other life distribution. Such a hypothesis turns out to be equivalent to the one that one failure rate is greater than the other and so the proposed test works as a competitor to more IFR tests by Kochar (1979, 1981) and Cheng (1985). Our test statistic utilizes the U-statistics theory and a large sample nonpara metric test is established. The power of the proposed test is discussed by calculating the Pitman asymptotic relative efficiencies against several alter native hypotheses. A numerical example is presented to exemplify the proposed test.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.425-429
• /
• 2008

The present study has been conducted to improve temperature distribution in the motor housing of vacuum cleaner and reduce the development period by CFD analysis. CFD analysis is performed to investigate the thermal flow pattern in the motor housing and validated by experiments. The validation of CFD analysis is conducted by comparing the temperature distribution on motor housing cover. Through the present study the CFD analysis procedure in the motor housing of vacuum cleaner is established and various experimental materials are obtained. These analysis results can be used effectively as design factors of vacuum cleaner.

• Journal of the Optical Society of Korea
• /
• v.18 no.2
• /
• pp.156-161
• /
• 2014

Anisotropy profile of a rubbed polyimide film is investigated using both a modified ultra high precision transmission ellipsometer and the analysis software previously developed to determine the optic axis distribution of discotic liquid crystals in the wide view film. The distorted sinusoidal variation of the ellipsometric constants obtained at an oblique angle of incidence indicates that the optic axis varies from $14.7^{\circ}$ to $40.6^{\circ}$ from the sample plane. The magnitude and distribution of anisotropy is expressed in terms of no, ne, and the cosine-shaped tilt angle distribution of the optic axis in a rubbed polyimide film.

• Korean Journal of Plant Taxonomy
• /
• v.41 no.2
• /
• pp.156-163
• /
• 2011

The morphological characteristics of Chionanthus retusus Lindl. & Paxton in Korea are reviewed in this study through the comparison with its previous records and a distribution map of this species is created using previous flora and voucher specimens. The leaf epidermal micromorphology and the petiole anatomy are also briefly described.

• Communications for Statistical Applications and Methods
• /
• v.20 no.5
• /
• pp.405-416
• /
• 2013

This paper develops a maximum profile likelihood estimator of unknown parameters of the exponentiated Gumbel distribution based on upper record values. We propose an approximate maximum profile likelihood estimator for a scale parameter. In addition, we derive Bayes estimators of unknown parameters of the exponentiated Gumbel distribution using Lindley's approximation under symmetric and asymmetric loss functions. We assess the validity of the proposed method by using real data and compare these estimators based on estimated risk through a Monte Carlo simulation.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.2
• /
• pp.317-325
• /
• 2010

In this paper, we develop four modified empirical distribution function (EDF) type tests using approximate maximum likelihood estimators for the half-logistic distribution based on multiply Type-II censored samples. We also propose modified normalize sample Lorenz curve polt and new test statistics. We compare the above test statistics in the sense of the power for various censored samples. We present an example to illustrate this method.

• Journal of the Korean Data and Information Science Society
• /
• v.24 no.1
• /
• pp.171-178
• /
• 2013

In this paper, we develop noninformative priors for the generalized Pareto distribution when the parameter of interest is the shape parameter. We developed the first order and the second order matching priors.We revealed that the second order matching prior does not exist. It turns out that the reference prior satisfies a first order matching criterion, but Jeffrey's prior is not a first order matching prior. Some simulation study is performed and a real example is given.

• Journal of information and communication convergence engineering
• /
• v.5 no.3
• /
• pp.289-294
• /
• 2007

With regard to a marine safety system, large vessels are generally loaded with INS (Integrated Navigation System). But although small and medium-sized ships are exposed to safety accidents in the sea, they are not carrying proper navigation devices and equipment. Accordingly, in order to develop INS for small and medium-sized ships(s-INS), an existing INS has newly been organized and integrated. Recently, more strict enforcement of INS-related regulations is expected at home and abroad, and the scope of their applications is being broadened. To keep up with this global trend that ships are being loaded with digital devices and equipment, this study has tried to develop s-INS, broadening its applications, and suggesting a future research plan.

• Journal of Korean Institute of Industrial Engineers
• /
• v.31 no.2
• /
• pp.120-126
• /
• 2005

Until now, the traditional production models and logistics have developed a broader strategic approach called supply chain. However, there are some obstacles to apply industry practice because of unrealistic assumptions. The most serious of them is that they assume the lead times are integer multiples of the planning time grid. This assumption makes it difficult to express the processing and transportation lags correctly. Thus, in this paper, we propose a new methodology for the integrated production/distribution model having non-integer time lags using the concept of dynamic production function. In case that the time lags are integer or non-integer, the dynamic production function reflects well the situation under given environments. Experiments show that the proposed model can express the real system more accurately than the prior model can.