• 제목/요약/키워드: Life Time Distribution Function

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지수형과 로그형 위험함수 학습효과에 근거한 NHPP 소프트웨어 신뢰성장모형에 관한 비교연구 (The Comparative Study of NHPP Software Reliability Model Exponential and Log Shaped Type Hazard Function from the Perspective of Learning Effects)

  • 김희철
    • 디지털산업정보학회논문지
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    • 제8권2호
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    • pp.1-10
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    • 2012
  • In this study, software products developed in the course of testing, software managers in the process of testing software test and test tools for effective learning effects perspective has been studied using the NHPP software. The finite failure nonhomogeneous Poisson process models presented and the life distribution applied exponential and log shaped type hazard function. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than autonomous errors-detected factor that is generally efficient model could be confirmed. This paper, a failure data analysis of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error and coefficient of determination.

Molecular Characterization and Tissue Distribution of Estrogen Receptor Genes in Domestic Yak

  • Fu, Mei;Xiong, Xian-Rong;Lan, Dao-Liang;Li, Jian
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권12호
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    • pp.1684-1690
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    • 2014
  • Estrogen and its receptors are essential hormones for normal reproductive function in males and females during developmental stage. To better understand the effect of estrogen receptor (ER) gene in yak (Bos grunniens), reverse transcription-polymerase chain reaction (PCR) was carried out to clone $ER{\alpha}$ and $ER{\beta}$ genes. Bioinformatics methods were used to analyze the evolutionary relationship between yaks and other species, and real-time PCR was performed to identify the mRNA expression of $ER{\alpha}$ and $ER{\beta}$. Sequence analysis showed that the ER open reading frames (ORFs) encoded 596 and 527 amino acid proteins. The yak $ER{\alpha}$ and $ER{\beta}$ shared 45.3% to 99.5% and 53.9% to 99.1% protein sequence identities with other species homologs, respectively. Real-time PCR analysis revealed that $ER{\alpha}$ and $ER{\beta}$ were expressed in a variety of tissues, but the expression level of $ER{\alpha}$ was higher than that of $ER{\beta}$ in all tissues, except testis. The mRNA expression of $ER{\alpha}$ was highest in the mammary gland, followed by uterus, oviduct, and ovary, and lowest in the liver, kidney, lung, testis, spleen, and heart. The $ER{\beta}$ mRNA level was highest in the ovary; intermediary in the uterus and oviduct; and lowest in the heart, liver, spleen, lung, kidney, mammary gland, and testis. The identification and tissue distribution of ER genes in yaks provides a foundation for the further study on their biological functions.

한반도내(韓半島內) 주요(主要) 인공구조물(人工構造物)의 적정(適正) 내진설계진도(耐震設計震度) (Optimum Intensity for Seismic Design of Major Man-made Structures in Korea)

  • 김성균
    • 자원환경지질
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    • 제19권4호
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    • pp.297-304
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    • 1986
  • Earthquake disaster is dependent upon both site intensity and strength of structures. The higher the strength, structures become more safe, which in turn increases the construction cost. Therefore, it is necessary to decide an optimum design intensity in which the safety is balanced with the cost. Such an optimum design intensity for major man-made structures in Korea is determined in the present study from a simulation model as follows. 1) Hypothetical earthquake time series are generated from the probability distribution to represent appropriately the seismicity of Korea. 2) The strength of structures constructed with a certain design intensity is assumed to exponentially decrease with the elapsed time. The construction cost is also expressed as a function of design intensity. 3) Comparing the seismic intensity generated from the earthquake time series with the strength of structures, the safety of structures is examined. Then the time until the structure is damaged by an earthquake is obtained within the designed life time. 4) The above simulation is iterated several hundred times and hence the mean life time of structures having a certain design intensity is obtained. 5) After all, the optimum design intensity to minimize the annual mean loss, the ratio of construction cost to mean life time, is estimated. The major conclusions obtained from the above simulation model are as follows. 1) Depending upon the designed life time ($T_p$), the optimum design intensities are appeared to be 0. 05-0. 10g for $T_p=50yr$ and 0. 08-0.13g for $T_p=100yr$. 2) According to the sensitivity analysis, the optimum design intensity increases with the rapid strength decrease of structure and decreases with the increase of initial construction cost.

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강도함수가 감소패턴을 따르는 NHPP 소프트웨어 신뢰모형에 관한 비교 연구 (A Comparative Study on Software Reliability Model for NHPP Intensity Function Following a Decreasing Pattern)

  • 김희철;김정범;문송철
    • Journal of Information Technology Applications and Management
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    • 제23권4호
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    • pp.117-125
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    • 2016
  • Software reliability in the software development process is an important issue. In infinite failure non-homogeneous Poisson process software reliability models, the failure occurrence rates per fault. can be presented constant, monotonic increasing or monotonic decreasing pattern. In this paper, the reliability software cost model considering decreasing intensity function was studied in the software product testing process. The decreasing intensity function that can be widely used in the field of reliability using power law process, log-linear processes and Musal-Okumoto process were studied and the parameter estimation method was used for maximum likelihood estimation. In this paper, from the software model analysis, we was compared by applying a software failure interval failure data considering the decreasing intensity function The decreasing intensity function model is also efficient in terms of reliability in the arena of the conservative model can be used as an alternating model can be established. From this paper, the software developers have to consider life distribution by preceding information of the software to classify failure modes which can be gifted to support.

비선형 강도함수 특성을 이용한 유한고장 NHPP모형에 근거한 소프트웨어 최적방출시기 비교 연구 (The Comparative Study of Software Optimal Release Time of Finite NHPP Model Considering Property of Nonlinear Intensity Function)

  • 김경수;김희철
    • 디지털융복합연구
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    • 제11권9호
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    • pp.159-166
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    • 2013
  • 본 연구에서는 소프트웨어 제품을 개발하여 테스팅을 거친 후 사용자에게 인도하는 시기를 결정하는 방출문제에 대하여 연구 하였다. 소프트웨어의 결함을 제거하거나 수정 작업과정에서 유한고장수를 가진 비동질적인 포아송과정에 기초하였다. 수명강도는 다양한 형상모수와 척도모수에 이용 할 수 있기 때문에 신뢰성 분야에서 많이 사용되는 비선형 특성을 가진 반-로지스틱 분포 모형을 이용한 방출시기에 관한 문제를 제시하였다. 소프트웨어 요구 신뢰도를 만족시키고 소프트웨어 개발 및 유지 총비용을 최소화 시키는 최적 소프트웨어 방출 정책에 대하여 논의 되었다. 본 논문의 수치적인 예에서는 고장 시간 자료를 적용하였으며 모수추정 방법은 최우추정법을 이용하고 최적 방출시기를 추정하였다. 따라서 소프트웨어 방출시기를 사전 정보로 활용하면 잠재적 보안피해액을 줄 일 수 있다고 판단된다.

항만 구조물의 최적 정밀점검 시기 추정을 위한 추계학적 결정모형의 개발 (Development of Stochastic Decision Model for Estimation of Optimal In-depth Inspection Period of Harbor Structures)

  • 이철응
    • 한국해안·해양공학회논문집
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    • 제28권2호
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    • pp.63-72
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    • 2016
  • 경사제 피복재와 같은 항만 구조물의 유지관리 계획에서 중요한 최적 정밀점검시기를 쉽게 결정할 수 있는 RRP(Renewal Reward Process)기반 기대할인비용모형인 추계학적 결정모형을 개발하였다. PIM(Periodic Inspection and Maintenance)과 CBIM(Condition-Based Inspection and Maintenance) 정책을 동시에 적용하여 이전 모형들의 한계성을 극복할 수 있는 수학적 모형을 수립하였다. 또한 모형에 연속복리계수를 도입하여 점검 및 보수보강과 관련된 비용들의 시간에 따른 가치변화를 고려하였다. 먼저 파괴율 함수가 일정한 조건에서 해석해를 유도하고, 분포함수에 따른 영향 등 다각적 민감도 분석을 수행하여 본 연구에서 유도된 해석해가 기존에 제시된 해석해를 포함하며 적용성이 더 우수함을 확인 할 수 있었다. 추계학적 확률과정을 이용하는 경우에도 본 연구에서 수립된 모형은 경사제 피복재와 같은 구조물의 추계학적 누적피해도의 비선형성을 올바로 해석할 수 있다. 특히 MCS(Monte-Carlo Simulation) 기반 표본경로기법을 사용하여 모형의 피해강도함수의 계수들을 비교적 쉽게 산정할 수 있었다. 마지막으로 본 연구에서 개발된 추계학적 결정 모형을 경사제 피복재에 만족스럽게 적용하였다. 누적피해의 거동 특성, 사용한계의 수준 그리고 구조물의 중요도에 따라 단위시간당 기대 총 비용이 최소가 되는 경사제의 피복재의 최적 정밀점검 시점을 비교적 쉽게 결정할 수 있었다.

혈청(血淸)콜레스테롤 농도(濃度)와 본능성고혈압(本態性高血壓), 간기능장애(肝機能障碍) 및 체중(體重)과의 상관관계(相關關係)에 대한 검토(檢討) (A Study on the Interrelation Between Serum Cholesterol level and Essential Hypertension, Liver Disease and Body weight)

  • 김명해
    • 보험의학회지
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    • 제2권1호
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    • pp.135-142
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    • 1985
  • For the past 10 years, the socioeconomic status of our country was markedly improved. Accordingly, our foodintake patterns and other alt parts are preparing to blance with developed countries. Especially, be westernizing or improving our foodintake patterns, we intake much fat diet(animal food) while our physical activities decrease and alcohol consumtion's population, smoking population gradually increase. For such reasons, the population of obese tendency and cardiovascular diseases are increased. According to recent reports, among all death causes in our country, cardiovascular diseases(hypertension, hypertensive cardiovascular diseases, ischemic heart diseases) occupyd top rank, we know. I(the author) studied the inter-relation between serum cholesterol level which is the important factor of the cardiovascular diseases and essential hypertension liver diseases, hyperglycemia, some cardiac problems which are main decline causes in life insurance's medical assessment, and body weight distribution. Studied samples were selected on 4,313 cases(male; 1,791, female; 2,522) who were tested liver function test from June, 11th, 1980 to Dec., 31st, 1983 on our medical department's laboratory. I selected two groups in those cases: one group was serum cholesterol level 180mg/dl over(11% of whole LFT examed cases: No=502 cases), the other group was serum cholesterol level 120-160mg/dl(No= 502 cases). For convenience, the group of serum cholesterol level 180mg/dl over was "A" the other group was "B", I described. All examed persons of LFT were resident m Tae-Jon city in that time. On the result, 1) Decline rate is 10.5% on the "A" group, 5.9% on the "B" group. "A" group reveals 1.8 times higher than "B" group. 2) On decline causes, Essential hypertension is 4.0 times higher on the "A" group than "B", liver function's abnormalities are 2.0 times higher on "A" group than "B" and other diseases are same on "A" and "B". On the "A" group, essential hypertension is considerably higher than "B" group. 3) On the body weight distribution, the cases of 70kg(B.W.) over is 19.7% on "A", 10.6% on "B" group. Obese tendency is 1.8 folds higher on "A" group than "B" group. Studing the result, we find high serum cholesterol concentration is closely related with essential hypertension, obese tendency and liver function's abnormalities on the life insurance's medical examination part, also. On the future, we will more carefully consider the serum cholesterol concentration on our medical examnination and assessment of life insurance, I think.

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어랑분포의 형상모수 변화에 따른 소프트웨어 개발 비용모형에 관한 비교 연구 (The Comparative Software Development Cost Model Considering the Change in the Shape Parameter of the Erlang Distribution)

  • 양태진
    • 한국정보전자통신기술학회논문지
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    • 제9권6호
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    • pp.566-572
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    • 2016
  • 소프트웨어 개발과정에서 소프트웨어 신뢰성은 매우 중요한 문제 중에 하나이다. 소프트웨어 고장현상을 분석하기 위하여 비동질적인 포아송과정에서 고장 발생 추이를 의미하는 위험함수가 고장시간에 독립적으로 일정하거나, 종속적인 경우, 즉 비-증가 또는, 비-감소하는 속성을 가질 수 있다. 본 연구에서는 소프트웨어 제품 테스팅 과정에서 고장 수명분포로서 어랑분포의 다양한 형상모수를 고려한 소프트웨어 개발 비용 분석에 대하여 연구되었다. 소프트웨어 고장현상을 분석하기 위하여 모수추정은 최우추정법이 사용되었다. 따라서 본 논문에서는 어랑분포의 형상모수를 고려한 소프트웨어 개발비용모형 분석을 위하여 소프트웨어 고장간격 시간자료를 이용하여 비교 및 평가하였다. 그 결과 형상모수에 따른 비용곡선을 비교 하였을 때 형상모형이 작을수록 비용이 많고 소프트웨어 최적 방출시간이 지연 됨을 알 수 있었다. 이 연구를 통하여 소프트웨어 개발자들에게 소프트웨어 형상모수에 따른 개발 비용을 탐색하는데, 기본적으로 도움을 줄 수 있는 사전정보의 역할을 할 수 있을 것으로 판단된다.

시간의존적 교량유지관리 모델 (Time Dependent Maintenance Models of Bridges)

  • 양승이
    • 한국강구조학회 논문집
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    • 제14권3호
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    • pp.443-452
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    • 2002
  • 고속도로 건설은 여러 국가에서 거의 완료되었으며, 정부나 고속도로 관계기관은 유지관리쪽에 초점을 맞추고 있다. 교량을 효과적으로 유지관리하기 위해, 시스템 신뢰성을 이용한 교량의 잔존수명을 예측하는 것은 매우 시급하다. 그리고 시스템 신뢰성을 이용한 교량의 유지관리 모델을 개발하는 것은 필수적이다. 이 논문에서는 시스템 신뢰성과 라이프 타임 분포를 이용하여 예방 유지관리(Preventive Maintenance)와 사후 유지관리(Essential Maintenance) 모델을 개발하였다.

브라운 운동을 따르는 열화현상을 이용한 일정스트레스 가속수명시험의 최적설계 (Optimal Design of Constant Stress Accelerated Life Tests Using Degradation Phenomenon Based on a Brownian Motion)

  • 서순근;김갑석;하천수
    • 품질경영학회지
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    • 제26권1호
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    • pp.74-87
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    • 1998
  • This study considers optimal design of accelerated life tests under constant stress using that the first passage time to cross a critical boundary through amount of accumulated degradation has an inverse Gaussian distribution when the degradation process follows to a Brownian motion with positive drift of log linear function of stress. Optimum plans for Type I censoring are derived by minimizing the asymptotic variance of estimated quantiles at the use stress. Sensitivity analyses are also conducted to see how sensitive the optimality criterion is with respect to the uncertainties involved in the guessed values.

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