• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.245-249
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• 1997

A feasibility study on the characterization of incipient insulator failure for distribution fault prediction is presented. In this study, real distribution data was collected and analyzed to isolate incipient failure signatures or parameters which were expected to show distinct behaviors before and after failure incident. Several signal analysis methods were applied to isolate the parameters and a new strategy of analysis, the event-date concept, was also applied to find a relationship between non-harmonic and high frequency signal activities and imminent insulator failures.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권4호
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• pp.305-315
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• 2017

Purpose: The purpose of this research is to propose procedure and methodology for developing failure rate databook which is suitable for Korean operation environment. Methods: To this end, we investigate failure databooks used in foreign countries and study the procedure and methodology for collecting failure data, organizing the data, estimating failure rate and summarizing results. Results: We develop the procedure of development of failure databook, the items for data collection, database schema of part details and part summary and contents of failure databook by considering the application environment in Korea. Conclusion: The results of our research could be utilized for the development of Korean failure rate databook and research of reliability prediction model and could ultimately contribute to improve the accuracy of reliability prediction.

• 한국정밀공학회지
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• 제14권7호
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• pp.91-98
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• 1997

Because of a complicated behavior of fatigue in mechanical structures, the analysis of fatigue is in need of much researches on life prediction. A method is developed for the dynamic tensile strength analysis by simple tensile test, which is for the failure life prediction by lethargy coefficient of various materials. Then it is programed to analyze the failure life prediction of mechanical system by virtue of fracture. Thus the dynamic tensile strength analysis is performed to evaluate life parameters as a numerical example, using the developed method.

• 산업경영시스템학회지
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• 제28권1호
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• pp.49-54
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• 2005

Recently, the reliability are applied for many industrial products, and many products are required to guarantee in quality and in performance. The purpose of this paper is to present some of reliability prediction methodologies using failure rate database for machinery parts that are applicable to machine tools. VDI Turret, which is core component of the NC Lathe, was chosen as the target of the reliability prediction. The results of reliability prediction has shown the failure rate, MTBF(Mean Time Between Failure), and reliability of the VDI Turret. It is expected that proposed methodologies will be applicable to prediction of reliability for other components of machine tools.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.305-318
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• 2011

In the statement of logistics reliability prediction methodology, all components should be managed as the analysis objectives. However, in some reliability prediction of weapon systems, fastening parts, e.g., screws, bolts and nuts, have been frequently ignored because some organizations related to weapon systems have emphasized that those parts are not significant in their failures rate and functions. In this paper, failure rates, modes, and distributions were presented to prove that fastening parts should be included in reliability prediction objectives. Also, failure rate prediction methods of fastening parts are presented and compared.

• 대한기계학회논문집A
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• 제34권9호
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• pp.1281-1286
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• 2010

발전소를 비롯한 각종 플랜트 설비는 많은 기계설비들로 구성되어 고장이 발생할 경우, 고장이 발생된 설비와 시간을 명확하게 파악하기가 쉽지 않다, 또한 고장발생시 정비비용 증가와 함께 설비의 이용률이 감소하여 막대한 경제적 손실이 발생한다. 발전소는 각종 계측센서를 설치하여 설비를 상시 감시하고 있으며, 경고발생 이전 지시치의 변화를 관찰하여 설비의 이상상태를 자동 감지하는 신호기반 고장 조기경보 시스템도 설치된 발전소도 있다. 그러나 고장경보 시스템은 이상신호 발생을 인지하여 설비의 이상상태 여부는 알려주지만 고장원인과 중요도에 대한 정보는 제공하지 않는다. 본 연구에서는 고장분석 기능을 가지고 있는 RCM(Reliability Centered Maintenance) 분석 시스템과 고장경보시스템을 연계하여 설비의 이상신호로부터 고장원인과 정비방법에 대한 정보를 제공하는 고장예측시스템을 개발하고자 한다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.73-77
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• 2004

Failure predictions of composite single-lap bonded joints were performed considering both of composite adherend failure and bondline failure. An elastic-perfectly plastic model of adhesive and a delamination failure criterion are used. The failure prediction results such as failure mode and strength have very good agreements with the test results of joint specimens with various bonding methods and parameters. The influence of variations in the effective strength (that is, adhesion performance) and plastic behavior of adhesive on the failure characteristics of composite bonded joints are investigated numerically. The numerical results show that optimal joint strength is archived when adhesive and delamination failure occur in the same time.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.433-445
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• 2011

Duty cycle is determined as the ratio of operating time to total time. Duty cycle in reliability prediction is one of the significant factors to be considered. In duty cycle application, non-operating time failure rate has been easily ignored even though the failure rate in non-operating period has not been proved to be small enough. Ignorance of non-operating time failure rate can result in over-estimated system reliability calculation. Furthermore, utilization of duty cycle in reliability prediction has not been evaluated in its effectiveness. In order to address these problems, two reliability models, such as MIL-HDBK-217F and RIAC-HDBK-217Plus, were used to analyze non-operating time failure rate. This research has proved that applying duty cycle in 217F model is not reasonable by the quantitative comparison and analysis.

• Journal of the Korean Data and Information Science Society
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• 제23권3호
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• pp.569-577
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• 2012

기업도산에 대한 분석과 관리는 기업의 성과와 성장능력을 평가하는 재무관리 분야에서 중요하게 인식되어 왔다. 결국, 기업도산 예측에 대한 효과적인 모형이 필요하게 된다. 본 논문은 서포트 벡터 기계의 한 종류인 토탈 여유도 알고리즘을 이용하여 기업도산 예측을 위하여 새로운 접근 방법을 서술한다. 몇 개의 실제 자료를 통하여 제안한 방법들이 도산 위험의 평가에서 기존의 방법들보다 개선됨을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제19권3호
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• pp.217-227
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• 2019

This study focuses on an improved prediction model to determine the limiting grouting pressure of compaction grouting considering the ground surface upheaval, which is caused by the three-dimensional conical shearing failure. The 2D-dimensional failure curve in Zou and Xia (2016) was improved to a three-dimensional conical shearing failure for compaction grouting through coordinate rotation. The process of compaction grouting was considered as the cavity expansion in infinite Mohr-Coulomb (M-C) soil mass. The prediction model of limiting grouting pressure of compaction grouting was proposed with limit equilibrium principle, which was validated by comparing the results in El-Kelesh et al. (2001) and numerical method. Furthermore, using the proposed prediction model, the vertical and horizontal grouting tube techniques were adopted to deal with the subgrade settlement in Shao-huai highway at Hunan Provence of China. The engineering applicability and effectiveness of the proposed model were verified by the field test. The research on the prediction model for the limiting grouting pressure of compaction grouting provides practical example to the rapid treatment technology of subgrade settlement.