• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.125-130
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• 2003

This paper provides approximate J estimates for off-centred, circumferential through-wall cracks in cylinders under bending. The proposed method is based on the reference stress approach, where the dependence of elastic and plastic influence functions of J on the cylinder/crack geometry, the off-centred angle and strain hardening is minimised through the use of a proper normalising load. Based on published limited FE results for off-centred, circumferential through-wall cracks under bending, such normalising load is found, based on which the reference stress based J estimates are proposed for more general cases, such as for a different cylinder geometry. Comparison of the estimated J with extensive FE J results shows overall good agreements for different crack/cylinder geometries which provides sufficient confidence in the use of the proposed method to fracture mechanics analyses of off-centred circumferential cracks. Furthermore, the proposed method is simple to use, giving significant merits in practice.

• 대한기계학회논문집A
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• 제26권1호
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• pp.139-146
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• 2002

This paper provides validations of the reference stress based J and $C^{*}$ estimations, proposed in Part I, for inner, circumferential surface cracked pipes under internal pressure and global bending against detailed 3-D elastic-plastic and elastic-creep FE results. For this purpose, actual tensile properties of two typical stainless steels (TP304 and TP316) are used for elastic-plastic FE analyses and two realistic creep laws are used for elastic-creep FE analyses. For a total of twenty cases considered in this paper, agreements between the proposed reference stress based J and $C^{*}$ estimations and the FE results are excellent. More important aspect of the proposed estimations is that they can be used to estimate J and $C^{*}$ not only at the deepest point of the surface crack but also at an arbitrary point along the crack front.front.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.17-25
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• 2001

This paper briefly describes the new engineering method, called the enhanced reference stress method, to estimate J (or $C^*$) for non-linear fracture mechanics analysis of defective components, recently proposed by authors. The proposed method offers significant advantages over existing methods in terms of its accuracy, simplicity and robustness. Examples of application of the proposed method to typical piping integrity problems such as through-wall cracked pipes under combined loading, and surface cracked pipes under internal pressure and bending are given. Excellent agreements between the FE J and $C^*$ results and those of the proposed method provide sufficient confidence in the use of the proposed method. One notable point is that the proposed method can be used to estimate J (or $C^*$) along the crack front of surface cracks. Moreover simplicity of the proposed method makes it easy to extend to more complex problems. Thus the proposed method is attractive to assess the significance of defects under practical situations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.310-315
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• 2001

This paper provides validations of the reference stress based J and $C^*$ estimations, proposed in Part I, for inner, circumferential surface cracked pipes under internal pressure and global bending against detailed 3-D elastic-plastic and elastic-creep FE results. For this purpose, actual tensile properties of two typical stainless steels (TP304 and TP316) are used for elastic-plastic FE analyses and two realistic creep laws are used for elastic-creep FE analyses. For a total of twenty cases considered in this paper, agreements between the proposed reference stress based J and $C^*$ estimations and the FE results are excellent. More important aspect of the proposed estimations is that they can be used to estimate J and $C^*$ not only at the deepest point of the surface crack but also at an arbitrary point along the crack front.

• Journal of the Korean Statistical Society
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• 제29권1호
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• pp.17-27
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• 2000

In this paper, we develop noninformative priors that are used for estimating the reliability of stress-strength system under the Burr-type X model. A class of priors is found by matching the coverage probabilities of one-sided Bayesian credible interval with the corresponding frequentist coverage probabilities. It turns out that the reference prior as well as the Jeffreys prior are the second order matching prior. The propriety of posterior under the noninformative priors is proved. The frequentist coverage probabilities are investigated for samll samples via simulation study.

• 한국산업정보학회논문지
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• 제4권4호
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• pp.47-52
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• 1999

본 논문에서는 Burr Type-X 분포하에서 stress-strength 의 신뢰도를 추정하는 데 사용되어지는 비정보적 사전분포들을 개발하는 것이다. 개발된 reference 사전분포가 first order matching 사전분포가 된다는 것이 밝혀졌으며, 또한 matching 사전분포하에서 사후분포의 타당성을 밝혔다. 소표본하에서, 고전적 포함확률들이 주여져 있다.

• 대한기계학회논문집A
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• 제28권3호
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• pp.311-317
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• 2004

This paper proposes engineering estimation equations for the maximum deflection of a cylinder subject to bending under elastic-plastic and elastic-creep conditions. Being based on the reference stress approach, the proposed equations are simple to use and can accommodate general tensile and creep behaviours. Validation against detailed 3-D FE results using actual stress-strain data and realistic creep-deformation data shows excellent agreement, which provides confidence in the use of the proposed equation. Based on the proposed equations, together with information on in-service inspection data, discussion is given how to estimate future time-dependent and time-independent deflection of the CANDU pressure tube. Thus the present result would be valuable information for integrity assessment of the CANDU pressure tube.

• 전산구조공학
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• 제11권1호
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• pp.153-160
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• 1998

본 연구에서는 가압열충격 사고로 소형 냉각재 상실사고를 가정하여 냉각재의 온도와 압력의 이력으로 부터 용기 벽의 온도분포를 구하고, 이로 부터 열응력과 압응력을 해석적으로 구하였다. 또 균열 선단에서의 응력강도계수와 파괴인성치를 ASME코드의 방법을 이용하여 구하였고, 이들을 시간에 따라 비교하여 균열의 진전여부를 평가하였다. 원자로 용기 벽에 존재하는 여러 형태의 균열이 견딜 수 있는 최대 기준무연성천이온도를 결정하였으며 평가 결과에 대하여 고찰하였다.

• Animal Bioscience
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• 제35권7호
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• pp.975-988
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• 2022

Objective: In this study, we aimed to identify long non-coding RNAs (lncRNAs) that play important roles in starvation stress, analyze their functions, and discover potential molecular targets to alleviate starvation stress to provide a theoretical reference for subsequent in-depth research. Methods: We generated a piglet starvation stress animal model. Nine Yorkshire weaned piglets were randomly divided into a long-term starvation stress group (starved for 72 h), short-term starvation stress group (starved for 48 h), and the control group. LncRNA libraries were constructed using high-throughput sequencing of piglet ileums. Results: We obtained 11,792 lncRNAs, among which, 2,500 lncRNAs were novel. In total, 509 differentially expressed (DE)lncRNAs were identified in this study. Target genes of DElncRNAs were predicted via cis and trans interactions, and functional and pathway analyses were performed. Gene ontology functions and Kyoto encyclopedia of genes and genomes analysis revealed that lncRNA-targeted genes mainly participated in metabolic pathways, cellular processes, immune system processes, digestive systems, and transport activities. To reveal the mechanism underlying starvation stress, the interaction network between lncRNAs and their targets was constructed based on 26 DElncRNAs and 72 DEmRNAs. We performed an interaction network analysis of 121 DElncRNA-DEmRNA pairs with a Pearson correlation coefficient greater than 0.99. Conclusion: We found that MSTRG.19894.13, MSTRG.16726.3, and MSTRG.12176.1 might play important roles in starvation stress. This study not only generated a library of enriched lncRNAs in piglets, but its outcomes also provide a strong foundation to screen key lncRNAs involved in starvation stress and a reference for subsequent in-depth research.

• 한국학교보건학회지
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• 제32권2호
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• pp.105-115
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• 2019

Purpose: The purpose of this study was to compare the mental health factors related to health risk behaviors between multicultural and monocultural adolescents. Methods: The study subjects were selected from the 2018 Korea Youth Risk Behavior Web-Based Survey Dataset. A total of 60,040 multicultural and monocultural adolescents were included in the analysis. A $x^2$ test and logistic regression were conducted, using SPSS 18.0, to compare the general characteristics, mental health, and health risk behaviors of the multicultural and monocultural adolescents. This process involved a complex sample design. Results: There was a significant difference in the rates of suicidal behaviors. Multicultural adolescents showed a significantly higher rate of suicidal ideation (8.6% vs. 8.5%, p=.004), suicidal plan (3.2% vs. 2.4%, p=.004), and suicidal attempt (5.0% vs 3.1%, p=.04) than monocultural adolescents. Perceived stress had a significant impact only on monocultural adolescents. Monocultural adolescents with high levels of perceived stress were at a greater risk of drinking (high stress=reference; low stress OR=0.91, p=.025) and smoking (high stress=reference; low stress OR=0.90, p=.029) than those with low stress. Multicultural adolescents who had made suicide attempts were at a higher risk of drinking (multicultural OR=7.879, p<.001; monocultural OR=2.481, p<.001) and smoking (multicultural OR=4.011, p=.015; monocultural OR=2.800, p<.001) than monocultural adolescents. Conclusion: To implement an effective smoking and drinking prevention program, it is necessary to consider how we can reduce the risk factors. Stress management is important for monocultural adolescents and a proactive suicide-screening program and a suicide prevention program should be included in the program for both multicultural and monocultural adolescents.