• 한국구조물진단유지관리공학회 논문집
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• 제10권3호
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• pp.165-175
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• 2006

사면거동 및 파괴를 분석하기 위하여, 일반적으로 암반사면에는 Polynomial model, 토사사면에는 Growth model을 별도로 적용하여 사용하여 왔다. 이 기법은 사면의 파괴예측보다 사면의 누적변위를 묘사하기 위한 그래프 형태 위주이다. 따라서 본 연구에서는 사면의 거동보다는 파괴 예측에 초점을 맞추어 일반적으로 사용되는 두 모델을 병합하여 파괴예측을 위한 Asymptote(점근선)과 누적변위량도 같이 묘사할 수 있는 3차 방정식 모델 (3-degree polynomial model)로 단일화 할 것을 제안하여 현장 계측 data를 분석하였다. 국도 절취 사면부인 단양군 고수재 사면과 영덕군 축산면에 위치한 영덕 사면에 본 해석 모델을 적용하였다. 고수재는 토사사면으로 Growth model에 다른 거동을 나타내었고, 영덕사면은 Polynomial model에 따른 거동을 나타내었다. 분석결과, Polynomial model 과 Growth model로 구분된 해석 모델 형태를 $y=ax^3+bx^2+cx+d$ 의 형태를 가지는 3차 방정식을 사용하면, 하나의 모델로 사면의 거동 및 파괴를 해석할 수 있으며, 그 거동 해석 및 파괴 예측능력이 더 우수하다는 것이 증명되었다. Polynomial model의 경우, 방정식의 차수를 증가시켜도, 그래프의 $R^2$값과 형태가 유사함을 알 수 있었다.

• 대한조선학회논문집
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• 제52권1호
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• pp.52-60
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• 2015

In the present study, an evaluation method for progressive failure of composite laminates has been proposed based on Puck's failure criterion and damage mechanics. The initial failure (or initiation of crack/delamination) has been assessed using Puck's failure criterion, and the progressive failure (or growth of crack/delamination) has been evaluated using fiber- and matrix-dependent damage variables. Based on Puck's failure criterion-damage mechanics coupling theories, the ABAQUS user-defined subroutine UMAT has been developed in order to analyze the progressive failure of glass/carbon fiber-reinforced composite laminates efficiently. In addition, the developed subroutine has been applied to progressive failure problem of industrial composite laminates, and the analysis results has been compared to experimental results which have been already reported in publications. It was confirmed that the simulation results were coincided well with the reported composite failure results.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1337-1343
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• 2004

Shape optimization was performed to obtain a precise shape of cutouts including the internal shape of cutouts in a laminated composite plate by three dimensional modeling using solid element. Volume control of the growth-strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. It makes Tsai-Hill failure index at each element uniform in laminated composites under the predetermined volume a designer requires. Shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study; (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminate composite, (2) The optimal shapes of the various load conditions and cutouts were obtained, (3) The maximum Tsai-Hill failure indices of the optimal shapes were remarkably reduced comparing with those of the initial shapes.

• 한국철도학회논문집
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• 제9권5호
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• pp.606-611
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• 2006

This paper presents a procedure and an analysis method to evaluate reliability of the Korea high-speed train. The rolling stock system is divided into 6 sub-systems and each subsystem is classified into sub-assemblies. Functional analysis has been conducted to draw reliability block diagrams for the sub-systems. First, failure rates has been calculated for each sub-assembly from the failure data obtained during commissioning tests. Then a reliability block diagram is used to evaluate the MKBF(Mean Kilometers Before Failure) of the sub-systems. Activities to increase reliability have been carried out throughout the test runs and analysis results show that the reliability of the rolling stock system is gradually growing in time.

• The Journal of Korean Physical Therapy
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• 제11권3호
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• pp.133-140
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• 1999

Why does the CNS not regenerate after injury? The failure of axonal regeneration in the CNS after injury is not due to an inherent inability of these neurons to regrowth axon. Recently, an inhibitory substrate effect of CNS has been discovered which could be directly invoked in the lack of regeneration. The failure of axon regrowth in the CNS is crucially influenced by the presence of neurtie growth inhibitor NI35/250 and possibly also by molecules such as myelin associated glycoprotein(MAG) and chondroitin sulphate proteoglycans(CSPGs). The application of the monoclonal antibody IN-1, which efficinetly neutralizes the N135/250 inhibitory molecules. This new finding has a strong impact on the development of, a new neuroscienctific research directed to stimulate axonal regeneration. In this review summarize the current knowledge on the factors and molecules involved in the regeneration failure.

• 기술혁신학회지
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• 제8권3호
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• pp.1175-1198
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• 2005

The objective of the study is to verify the relationship between technology valuation indexes and corporate's performance in ventures by business operating periods. The result of the study is expected to be useful in loan evaluation, investment decision, internal management decision making and business improvement. The results of study is as follows. First, in early stage ventures, we find that three major valuation index(technology feasibility, economic efficiency, productivity) are significant ex-ante variables which are discriminating between firms' going concern and firms' failure. Second, in growth stage ventures, we find that three major valuation index(business feasibility, general marketability, technology marketability) are significant ex-ante variables which are discriminating between firms' going concern and firms' failure. Third, in early stage ventures, we find that at least thirty-eight minor valuation index elements are significant ex-ante variables which are discriminating between firms' going concern and firms' failure and in growth stage ventures, thirty-one minor valuation index elements are significant in various analysis' results.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1361-1369
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• 2008

The analysis of software reliability model provides the means to analysts, software engineers, and systems analysts and developers who want to predict, estimate, and measure failure rate of occurrences in software. In this paper, reliability growth model, in which the operating time between successive failure is a continuous random variable, is proposed. This model is based on order statistics of two parameters Burr type XII distribution. We propose the measure based on U-plot. Also the performance of the suggested model is tested on real data set.

• 한국안전학회지
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• 제29권3호
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• pp.136-142
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• 2014

Recently a new version of PRO-LOCA program was released. Using the program, failure probability of pipes can be evaluated considering fatigue and/or stress corrosion crack growth and the effects of various parameters on the integrity of pipes in nuclear power plants can be evaluated quantitatively. The analysis results can be used to establish an inspection plan and to examine the effects of important parameters in a maintenance plan. In this study, sensitivity analyses were performed using the program for several important parameters including sampling method, initial crack size, number of initial fabrication flaws, operation temperature, inspection interval, operation temperature and nominal applied bending stress. The effect of parameters on the leak and rupture probability of pipes was evaluated due to fatigue or stress corrosion crack growth.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.702-709
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• 2004

Modified Gurson model (Gurson-Tvergaard-Needleman model) was used to analyze crack growth in M(T) and C(T) specimens. A commercial finite element code ABAQUS/Explicit is used to account for total failure of material point by cavity coalescence, and crack growth was simulated by finite element extinction. Crack growth resistance curve was obtained by calculating J-integral. Crack growth under residual stress was investigated.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제3권1호
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• pp.68-74
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• 2000

목 적: 연구자들은 삼성의료원 소아과에 상기 증상으로 내원한 환아의 임상상을 알아보고자 본 연구를 시행하였다. 방 법: 1997년 3월부터 1999년 7월까지 failure to thrive를 주소로 삼성의료원 소아과 영양크리닉을 방문한 16세 이하의 영아 및 소아 환자 74명을 대상으로 후향적인 방법으로 병록지 고찰을 통하여 임상 상을 알아보았다. 외래를 내원하였을 때 환아의 출생체중, 체질성 성장지연의 가족력을 포함하는 병력청취와 신체검사를 시행하였고, failure to thrive가 병력 및 신체검사로 설명이 되지 않는 경우는 흉부 방사선촬영, 간 기능 검사, 전해질 검사, 신장기능 검사, 혈액 검사, 요침사를 포함하는 소변검사를 시행하였고 필요한 경우 뇌파검사, Brain MRI, 골 연령 등을 측정하였다. 또한 영양사의 도움을 얻어 현재 섭취하고 있는 음식의 열량을 분석하였다. 결 과: 1) 74명의 환아의 병록지 고찰이 가능하였고 이중 남아가 43명이었으며 나이는 1개월에서 13년 1개월(평균: $3.3{\pm}3.7$세)이었다. 2) 전체적으로 원인을 추정할 수 있었던 총 69례 중 생리적 failure to thrive는 33례로 전체 47.8%, 병적인 failure to thrive는 36례로 52.2%를 차지하였고, 생리적 failure to thrive에서는 가족성 저신장증, IUGR, 체질성 성장지연, Idiosyncrasy, 미숙아 순이였고 병적 원인의 경우 나이와 관계없이 중추 신경계질환, 위장관 질환, 알레르기 질환 순이었다. 3) 3세 미만의 군에서는 원인을 추정할 수 있었던 총 41례 중 19례(46.3%)가 생리적 원인이었고 IUGR과 가족성 저신장증이 가장 많았다. 4) 3세 이상의 군에서는 원인을 추정할 수 있었던 28례의 환아 중 14례(50%)에서 생리적 원인으로 가족성 저신장증, 체질성 성장지연, IUGR 순이었다5). 평균 섭취열량은 하루 권장량의 76.2%였다. 체질성 성장지연과 IUGR, Idiosyncrasy, 병적 failure to thrive는 평균 섭취열량이 적은 경향을 보였고, 미숙아는 비교적 정상적인 소견을 보였으며 가족성 저신장증의 경우 열량 공급이 고루 분포되는 경향을 보였다. 5) 신체형은 생리적 failure to thrive의 원인 중 미숙아, IUGR과 병적인 failure to thrive에서는 신장과 체중 모두 감소되어 있는 형이 가장 많았고, 체질성 성장지연과 가족성 저신장증에서는 신장은 정상이나 체중은 감소되어 있는 형이 많았다. 결 론: Failure to thrive는 3세 미만에서는 IUGR 및 가족성 저신장증 등이 failure to thrive의 가장 흔한 원인이고 3세 이상에서는 가족성 저신장증과 체질성 성장지연 등 유전환경이 가장 흔한 원인이다. 병적인 failure to thrive의 원인은 나이와 관계없이 중추 신경계질환, 위장관 질환이 가장 흔한 원인이다. 영 유아를 포함하는 소아에서의 failure to thrive의 원인은 대개 치료가 필요하지 않는 생리적인 원인이 많고 완전한 병력청취 및 신체 검사만으로도 진단이 가능하므로 조기 진단 후 적절한 영양평가는 중요하리라 생각된다.