• 한국통계학회:학술대회논문집
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• 한국통계학회 2004년도 학술발표논문집
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• pp.295-300
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• 2004

We consider a G/M/1 queue with two-stage service policy. The server starts to serve with rate of ${\mu}1$ customers per unit time until the number of customers in the system reaches A. At this moment, the service rate is changed to that of ${\mu}2$ customers per unit time and this rate continues until the system is empty. We obtain the stationary distribution of the number of customers in the system.

• Journal of the Korean Data and Information Science Society
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• 제10권1호
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• pp.261-269
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• 1999

정보통신 기술의 급격한 발전과 경영 환경의 변화는 기업업무의 근본적인 변화와 함께 컴퓨팅 환경도 사용자 중심의 정보시스템으로의 이행이 심화되고 있다. 특히, 클라이언트/서버 환경의 분산 컴퓨팅과 인터넷을 기반으로 한 정보시스템 구축은 기업경쟁력 강화와 새로운 부가가치 측면에서도 발상의 전환을 요구하고 있다. 본 논문에서는 단위별로 처리해야 할 다양하고 방대한 정보들을 통계처리하고 그래프를 이용해서 효율적으로 정보를 표현한다. 이를 위해 해마다 발간되는 창원시의 통계정보를 웹 상에서 자바와 오라클 데이터베이스를 이용해서 시스템을 구현하였다. 사용자는 보편적인 인터페이스인 웹을 통해 지역의 통계정보를 제공받을 수 있다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.243-250
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• 2001

Industrial machines are sometimes exposed to the danger of earthquake. In the design of a mechanical system, this factor should be accounted for from the viewpoint of reliability. A method to analyze a complex nonlinear structure system under random excitation is proposed. First, the actual random excitation, such as earthquake, is approximated to the corresponding Gaussian process far the statistical analysis. The modal equations of overall system are expanded sequentially. Then, the perturbed equations are synthesized into the overall system and solved in probabilistic way. Several statistical properties of a random process that are of interest in random vibration applications are reviewed in accordance with nonlinear stochastic problem. The obtained statistical properties of the nonlinear random vibration are evaluated in each substructure. Comparing with the results of the numerical simulation proved the efficiency of the proposed method.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.325-332
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• 2003

This study was to develop a system for grading apples by their color using statistical image processing. T-test was used to detect edges in apple images and the chain code method was used for contour coding. The histogram and mean gray level of each RGB channel in a ring-shaped region was used to compare apple colors to reference apple color.

• 응용통계연구
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• 제10권1호
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• pp.37-46
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• 1997

통계청이 개발하여 서비스하고 있는 통계정보시스템 KOSIS(Korean Statistical Information System)의 이용실태를 통계행정 개선을 위한 설문조사 결과를 토대로 정리하고, KOSIS의 문제점과 개선책, 이용증대방안을 토의한다.

• Journal of the Korean Statistical Society
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• 제31권2호
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• pp.199-212
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• 2002

This article introduces transfer function model (TFM) with conditional heteroscedasticity where ARCH concept is built into the traditional TFM of Box and Jenkins (1976). Model building strategies such as identification, estimation and diagnostics of the model are discussed and are illustrated via empirical study including simulated data and real data as well. Comparisons with the classical TFM are also made.

• Journal of the Korean Statistical Society
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• 제34권1호
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• pp.39-47
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• 2005

We adopt the P/sub λ, T//sup M/ policy of dam to introduce a service policy with alternating service rates for a Poisson arrival queue, in which the service rate alternates depending on the number of customers in the system. The stationary distribution of the number of customers in the system is derived and, after operating costs being assigned to the system, the optimization of the policy is studied.

• Communications for Statistical Applications and Methods
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• 제4권2호
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• pp.497-505
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• 1997

We attempt to get a probabilistic model of a queueing system in the maximum entropy condition. Applying the maximum entropy principle to the queueing system, we obtain the most uncertain probability model compatible with the available information expressed by moments.

• Journal of Chest Surgery
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• 제27권9호
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• pp.732-737
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• 1994

From January 1983 to December 1992, There were 1441 papers in the Korean Journal of Thoracic and Cardiovascular Surgery. Among these papers, 783[54.3%] were original article or clinical analysis and 652[45.2%] were case reports. A total of 319 papers contained some statistical analysis. In 150 cases[47.0%] of these 319 papers, the statistical description was insufficient. Of the correctly described papers, 115[68%] had more than one statistical error. Of course, in many cases the errors were not considered to be severe, but they were often sufficient to raise doubts about some inferences. We suggest that authors should be more careful when they describe and apply statistical methods. If possible, authors should interpret results with statistical specialists. And we also suggest that our society have more extensive statistical refereeing system. This would at least prevent the worst errors from appearing in print. The last suggestion is elementary instruction in statistical methods during preclinical training.

• 대기
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• 제31권5호
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• pp.473-488
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• 2021

A new physical/statistical diagnostic downscale model has been developed for use to improve near-surface air temperature forecasts. The model includes a series of physical and statistical correction methods that account for un-resolved topographic and land-use effects as well as statistical bias errors in a low-resolution atmospheric model. Operational temperature forecasts of the Local Data Assimilation and Prediction System (LDAPS) were downscaled at 100 m resolution for three months, which were used to validate the model's physical and statistical correction methods and to compare its performance with the forecasts of the Korea Meteorological Administration Post-processing (KMAP) system. The validation results showed positive impacts of the un-resolved topographic and urban effects (topographic height correction, valley cold air pool effect, mountain internal boundary layer formation effect, urban land-use effect) in complex terrain areas. In addition, the statistical bias correction of the LDAPS model were efficient in reducing forecast errors of the near-surface temperatures. The new high-resolution downscale model showed better agreement against Korean 584 meteorological monitoring stations than the KMAP, supporting the importance of the new physical and statistical correction methods. The new physical/statistical diagnostic downscale model can be a useful tool in improving near-surface temperature forecasts and diagnostics over complex terrain areas.