• Nuclear Engineering and Technology
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• 제49권2호
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• pp.327-334
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• 2017

Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015-2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.

• 대한가정학회지
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• 제39권3호
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• pp.135-149
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• 2001

The purpose of this study was to investigate depression and school adjustment of institutionalized children and adolescents according to their ego-identity, gender, grade(age), relationship with parents before entering the institution, cause of entering the institution, duration of entering the institution, parents'visiting, psychological environment of institution. The subjects were 121 5th and 6th graders(59 boys and 62 girls), 135 middle school (58 boys and 77 girls), and 85 high school students (44 boys and 41 girls), who were institutionalized in Seoul. The data were analyzed by t-test, one-way and two-way ANOVA, Scheffe'test, and multiple regression analysis. The major findings of this study were as follows: 1) Depression and school adjustment of institutionalized children and adolescents were different according to their ego-identity, relationship with parents before entering the institution and psychological environment of institution. And school adjustment of institutionalized children and adolescents were different according to grade(age). 2) In regression analysis models, ego-identity and cause of entering the institution were significant predictors of depression, and ego-identity more predicted to depression than cause of entering the institution. And ego-identity and age(grade) were significant predictors of school adjustment, and ego-identity predicted to school adjustment as well as grade(age).

• 한국가스학회지
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• 제24권1호
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• pp.56-65
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• 2020

일반적으로 화재는 다양한 원인으로 발생하며 무작위로 보이기에 화재의 발생을 예측한다는 것은 매우 도전적인 문제이다. 하지만 모든 화재가 아닌 큰 피해를 주는 초대형 화재사고의 예측이 가능하다면, 선제적 대응을 통한 손실 최소화를 기대할 수 있다. 본 연구에서는 국가 전체를 대상으로 초대형 화재사고를 예측하기 위해 기계학습 기법인 k-평균 클러스터링을 이용하여 화재사고를 분류하고, 이를 인위적인 설정이 강한 비전문가 기준, 전문가 기준 분류 결과와 비교하여 예측에 적절한 분류 기준을 제안하였다. 비교 결과 기계학습을 이용한 분류가 일정한 피해규모와 비율로 분류되어, 예측에 적절한 분류 기준이라 판단하였다. 또한 초대형 화재사고의 주기성을 분석한 결과 일정한 패턴을 보였지만 높은 편차를 보였다. 따라서 단순 예측기법이 아닌 고급 예측기법을 사용하였을 때 초대형 화재사고의 발생 예측이 가능하다고 판단되었다.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.57-60
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• 2012

In this paper, we have performed a safety analysis on an automotive evaporator inspection system. We performed the bi-directional analysis on the manufacturing line. Software Fault Tree Analysis (SFTA) as backward analysis and Software Failure Modes, Effects, & Criticality Analysis (SFMECA) as forward analysis are performed alternately to detect potential cause-to-effect relations. The analysis results indicate the possibility of searching and summarizing fault patterns for future reusability.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2563-2566
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• 2007

TFT LCD industries have endeavored to adopt the piezo Drop-On-Demand (DOD) inkjet printing technology to production lines of TFT LCD color filters and these efforts have significantly been based on experimental works. Because the degree of complexity in the piezo DOD inkjet printing technology results in too many combination of parameters, the matrix experimental method to investigate all possible sets of parameters becomes ineffective and hence the basic understanding of the piezo Drop-On-Demand inkjet print technology becomes important. In this study, one possible cause of the droplet volume variation across nozzles, which might cause visible swathe marks on an inkjet patterned TFT LCD color filter, is theoretically investiaged and new R&D directions are suggested.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2567-2570
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• 2013

Background: This study analyzed Surveillance, Epidemiology and End Results (SEER) data to assess if socio-economic factors (SEFs) impact on endometrial cancer survival. Materials and Methods: Endometrial cancer patients treated from 2004-2007 were included in this study. SEER cause specific survival (CSS) data were used as end points. The areas under the receiver operating characteristic (ROC) curve were computed for predictors. Time to event data were analyzed with Kaplan-Meier method. Univariate and multivariate analyses were used to identify independent risk factors. Results: This study included 64,710 patients. The mean follow up time (S.D.) was 28.2 (20.8) months. SEER staging (ROC area of 0.81) was the best pretreatment predictor of CSS. Histology, grade, race/ethnicity and county level family income were also significant pretreatment predictors. African American race and low income neighborhoods decreased the CSS by 20% and 3% respectively at 5 years. Conclusions: This study has found significant endometrial survival disparities due to SEFs. Future studies should focus on eliminating socio-economic barriers to good outcomes.

• 한국건축시공학회지
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• 제14권1호
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• pp.76-86
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• 2014

The cause of crack on reinforced concrete structures is varied, while the studies, which have intended to analyze this in the material side, have been the mainstream so far. Therefore, in this study, we intended to suggest the proposals for enhancement of the system to reduce crack and to improve the quality of the reinforced concrete structures, by reviewing the cause of crack mainly in the structural aspect and analyzing the practices and the system. The result has been shown as following. (1) As one of the measures for improving the constructional system related to the structure, it is to enhance the relevant system so that design on construction, structure, and equipment, can be separately ordered or jointly ventured, and the owner or the agent of the owner can discuss and mediate the business in each specialized field. (2) Importance on construction supervision and new establishment of regulations related to structure supervision.

• 제어로봇시스템학회논문지
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• 제9권2호
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• pp.159-167
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• 2003

This study suggests the hybrid fault diagnosis method of signed digraph (SDG) and partial least squares (PLS). SDG offers a simple and graphical representation for the causal relationships between process variables. The proposed method is based on SDG to utilize the advantage that the model building needs less information than other methods and can be performed automatically. PLS model is built on local cause-effect relationships of each variable in SDG. In addition to the current values of cause variables, the past values of cause and effect variables are inputted to PLS model to represent the Process armies. The measured value and predicted one by dynamic PLS are compared to diagnose the fault. The diagnosis example of CSTR shows the proposed method improves diagnosis resolution and facilitates diagnosis of masked multiple-fault.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2006년도 춘계공동학술대회
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• pp.447-470
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• 2006

According to Granger causality test, yield of Cooperate Bond and export amount of Machinery have a meaning at statistical Confidence level of 10%. In case of index of the unit cost of export and export amount of Machinery, they have an interactive Granger cause. In yen dollar exchange rate and export amount of Machinery, former variable gives an unilateral Granger cause to latter that. Also, call rate gives an unilateral Granger cause to export amount of Machinery. In case of $M_3$ & export amount of Machinery, former variable have an influence on latter that at 5% Confidence level.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1792-1797
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• 2007

This paper try to find root-cause of failure in a connector used in transmitting signals for throttle body control in automotives by analyzing possible failure causes and performing experiments to simulate the cable failure in field. The connector comprises fins, wires, and case moldings. The failure is due to degradation of initial clamping force required fixing fins and wires in the connector. Expansion and compression of the case molding material surrounding fins would cause the degradation. Investigations of strict initial claming force and control of thermal expansion property of the molding are required to prevent the failure.