• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.439-445
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• 2005

This paper is to investigate the approximate confidence limits of the reliability performances (such as failure rate, reliability function and average life) for a cold standby series system. The Bayesian approximate upper confidence limit of failure rate is obtained firstly, and next Bayesian approximate lower confidence limits for reliability function and average life are presented. The expressions for calculating Bayesian lower confidence limits of the reliability function and average life are also obtained, and an illustrative example is examined numerically by means of the Monte-Carlo simulation. Finally, the accuracy of confidence limits is discussed.

• Journal of the Korean Data and Information Science Society
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• 제8권1호
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• pp.49-58
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• 1997

We consider the quantile function for the bootstrapped product limit estimate under left truncation and right censoring model and show its weak convergence. We also obtain bootstrapped confidence bands for the quantile function.

• 대한수학교육학회지:학교수학
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• 제12권3호
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• pp.273-299
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• 2010

본 논문의 목적은 고등학교 수준의 학생들이 표집분포의 개념을 학습할 수 있도록 '표집분포 시뮬레이션 (Sampling Distributions Simulation)'을 설계하고 구현하는 것이다. '표집분포 시뮬레이션'은 다음과 같이 4차시로 구성되어 있다. 1차시-신뢰도와 신뢰구간의 의미 학습하기 2차시-표집분포의 의미 학습하기 3차시-중심극한정리의 의미 학습하기 4차시-이항분포의 정규근사 학습하기 본 연구를 통하여 표집분포의 중요성에 대한 학생들이 인식이 달라지고 이해가 증진되기를 기대한다. 또 본 연구의 결과로 제공되는 프로그램 '표집분포의 시뮬레이션' 수업을 통해 통계적 추론 능력이 향상되고, 아울러 통계적 추론 속에서 표집 분포의 역할이 충분히 이해되기를 기대한다.

• 한국산업융합학회 논문집
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• 제5권1호
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• pp.3-9
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• 2002

In the field of design of mechanical structure and expectation of life time, characteristic of fatigue limit comes out to he the most important problem. In this paper, in order to get fatigue limit, (I) investigate the aspects of economy, time and confidence comparing two methods: the method by fracture probability introducing statistical conception and the staircase method. And (II) examine the experience approaching fatigue limit and coaxing effect. The value of fatigue limit by staircase method in very effective in view of practical use, and coaxing comes out by the same material effect as restraining crack progress, not as strengthening the tip of crack alone.

• Journal of Radiation Protection and Research
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• 제29권4호
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• pp.221-230
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• 2004

방사선작업종사자에게 발생한 암의 방사선 인과도를 평가하기 위한 통계적 측도로 인과확률(Probability of Causation)이 주로 이용된다. 인과확률의 계산 과정에는 다양한 형태의 불확실성이 존재하며, 따라서 인과확률은 하나의 점추정치(point estimate)가 아니라 여러 불확실성을 반영한 분포 또는 신뢰구간으로 평가되어야 한다. 본 연구에서는 국내 방사선작업종사자에게서 발생한 암의 방사선 인과도를 평가하기 위하여, 한국인의 기저자료를 반영하며 가장 최근에 발표된 NCI-CDC 모형에 근거하여 인과확률의 분포를 계산하도록 개발된 전산 프로그램 RHRI-PEPC를 소개한다. 또한 방사선작업종사자의 가상 피폭시나리오에 대한 모의실험을 통해, 인과확률의 점추정치와 불확실성 분포에 의한 방사선 인과도 평가 결과의 차이를 살펴보고 분포에 의한 평가의 경우 적절한 신뢰도 선택의 필요성을 제시한다.

• 지질공학
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• 제25권1호
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• pp.9-20
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• 2015

A strainmeter goes through a period of instability immediately after installation. To determine the stability of strainmeters installed around the Andong fault zone, South Korea, an x-MR control chart analysis and a T² control chart analysis were conducted. The x-MR control chart analysis used an empirically determined 3σ control limit line to identify abnormal data in recently installed strain gauges. In the T² control chart analysis, the control limit line was set at a confidence of 95%. A comparison of the early stage of measurement with the terminal stage of measurement for three months after installation indicates that stabilization depends on the location and direction of each strain gauge in x-MR control chart analysis. In the T² control chart analysis, the number of values exceeding the control limit line decreased as the terminal stage was approached. Based on these results, it is suggested that the 3σ control limit line of an x-MR control chart can be used as a standard for single gauge stability, and that the 95% confidence limit of a T² control chart analysis could be used as the standard for the stability of multi-gauge strainmeters.

• 한국패류학회지
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• 제24권1호
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• pp.59-66
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• 2008

본 연구는 피조개의 용존산소에 대한 내성을 구명하기 위하여 경남 진해만에 서식하는 피조개를 대상으로 수온과 염분에 대한 용존산소 농도별 생존율, 산소소비율 및 외부 형태 변화 등을 조사하였다. 피조개의 용존산소에 대한 $LC_{50}$은 수온 $15^{\circ}C$-일반해수와 염분 $26{\pm}1$ psu에서 7일 동안 각각 1.98mg/L (신뢰한계: 1.45-2.39 mg/L)와 2.63 mg/L (신뢰한계: 1.76-3.37mg/L)였다. 한편 $25^{\circ}C$-일반해수와 염분 $26{\pm}1$ psu에서는 각각 3.89 mg/L (신뢰한계: 3.36-4.55 mg/L)과 3.74 mg/L (신뢰한계 3.19-4.43 mg/L)으로 고수온에서 용존산소에 대한 내성이 약한 것으로 나타났다. 산소소비율은 모든 실험구에서 저산소 노출기간동안 감소하였으며, 회복가능성을 파악하기 위하여 일반해수로 전환시킨 경우 산소소비율을 증가시키며 산소부채에 의한 회복반응을 보였으나 모두 폐사하였다. 저산소 노출기간동안 패각 각정부위의 색깔이 검게 변화하는 것이 관찰되었다. 이 자료는 피조개 집단 폐사원인 구명을 위한 기초자료로 활용할 수 있을 것으로 여겨진다.

• Biomolecules & Therapeutics
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• 제12권1호
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• pp.43-48
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• 2004

The present study was carried out to investigate the potential acute toxicity of CKD-602 by a single intravenous dose in Sprague-Dawley rats. Ten males females were used in each test groups: a vehicle control, 34.7, 4l.7, 50.0, 60.0 and 72.0 mg/kg groups, and were given different single intravenous doses of CKD-602 to the test animals. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period following the administration. At the end of l4-day observation period, all animals were sacrificed and complete gross postmortem examinations were performed. One, 1, 2, 8 and 9 cases of deaths occurred in the male dose groups of 34.7, 41.7, 50.0, 60.0 and 72.0 mg/kg, respectively, and 1, 5 and 9 cases in the female dose groups 50.0, 60.0 and 72.0 mg/kg, respectively. An increase in the incidence of clinical signs such as alopecia, skin pallor skin ulcerations, emaciation and change of fecal material was found in the both sexes of all treatment groups. A decrease or Suppression in the body weight was also observed in a dose-dependent manner. In autopsy, male and/or female rats of the treatment groups showed treatment-related gross findings such as splenomegaly, atrophy of the testis, epididymis, seminal vesicles, ovary, uterus and thymus which were dose-dependent in incidence and severity. Based on these results, it was concluded that a single intravenous injection of CKD-602 to rats caused significant toxicities in gastrointestinal, hematopoietic, and reproductive systems. The $LD_{50}$ value was 53.8 (95% confidence limit: 48.5~60.6) mg/kg for males and 60.l (95% confidence limit: 55.3~65.8) mg/kg for females. The $LD_{10}$ value was 39.9 (95% confidence limit: 3l.7~44.8) mg/kg for males and 50.3 (95% confidence limit: 40.6~54.8) mg/kg for females.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.497-505
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• 2003

Under normality assumption, the tolerance interval for a future observation is sometimes of great interest in statistics. In this paper, we state the influence function on the standard deviation $\sigma$, and use it to derive the influence function on tolerance limits. Simulation study shows that the two influence functions perform very well.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.672-676
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• 2002

In this paper, a reliability-based design optimization method, which enables the determination of optimum design that incorporate confidence range for structures, is studied. Response surface method and Monte Carlo simulation are utilized to determine limit state function. The proposed method is applied to the I-type steel structure for reliability based optimal design.