• Title/Summary/Keyword: Quantitative Reliability Evaluation

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A New Evaluation Method for LCD Panel Anti-Smudge Treatment

  • Lee, Kyoung-Jin;Huh, Su-Jung;Suh, Duck-Jong;Ahn, Seon-Hong;Kim, Kyeong-Hyeon;Kim, Sang-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.299-301
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    • 2008
  • We suggest a new method to evaluate the anti-smudge performance of LCD panels. The anti-smudge performance is characterized by oleic acid contact angle. This method shows accurate and reproducible result and overcomes the difficulty of quantitative evaluation for the anti-smudge characteristic and low reliability in several proposed measurements.

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Evaluation Algorithm of Interruption Cost in Distribution Systems Interconnected with Dispersed Storage and Generation Systems (분산형전원이 도입된 배전계통에서의 정전비용산출 알고리즘에 관한 연구)

  • Rho, Dae-Seok;Choi, Jae-Suk;Cha, Jun-Min;Kim, Deok-Young
    • Proceedings of the KIEE Conference
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    • 2000.11a
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    • pp.82-84
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    • 2000
  • This paper deals with a evaluation algorithm of interruption cost in distribution systems in the case where Dispersed Storage and Generation (DSG) systems are interconnected with the distribution systems. If DSG systems are operated as the function of the load levelling in distribution systems at the normal conditions and as the uninterruptible power supply in fault areas at the emergency conditions, the reliability improvement of the distribution systems can be expected. In other words, the benefit can be represented by the cost avoiding interruption according to the operation of DSG systems when a fault is occurred. Therefore, this paper presents the evaluation algorithm for interruption cost in order to evaluate the benefit for the uninterruptible power supply of DSG systems in a quantitative manner.

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Reestablishment of RPN Evaluation Method in FMEA Procedure for K21 (K21 보병전투차량에 FMEA 적용을 통한 RPN 평가방법 재정립)

  • Lee, Chang-Hee;Yang, Kyung-Woo;Kim, Sang-Bu
    • Journal of Korean Society for Quality Management
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    • v.40 no.3
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    • pp.306-315
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    • 2012
  • Purpose: To ensure good quality munitions, we require quantitative risk management and optimal risk management of system characteristics. Methods: Failure mode and effects analysis (FMEA) is a widely used technique to assess or to improve reliability of products at early stage of design and development. Traditionally, the prioritization of failures for corrective actions is performed by developing a risk priority number (RPN). Results: This paper reestablishes an effective methodology for prioritization of failure modes in FMEA procedure. Revised evaluation criteria of RPN are devised. Conclusion: To verify the proposed methodology, it is applied to RPN evaluation for K21 infantry combat vehicle.

Real-Time Evaluation of Friction Weld Quality of Small-Type Hydraulic Valve Spool by Acoustic Emission (AE에 의한 소형 밸브스풀 마찰용접 품질의 실시간 평가)

  • 오세규;오정환;전태언;김경균;오명석
    • Journal of Welding and Joining
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    • v.12 no.2
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    • pp.97-107
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    • 1994
  • Both in-process quality control and high reliability of the weld is one of the major concerns in applying friction welding to the economical and qualified mass-production. No reliable nondestructive monitoring method is available at present to determine the real-time evaluation of automatic production quality control for friction welding of special hydraulic valve spool of 16mm in diameter. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the tensile strength and other properties of the welded joints of $\phi16$ valve spool as well as the various welding variables, as a new approach which attempts finally to develop real-time quality monitoring system for friction welding.

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Dynamic Response based System Reliability Analysis of Structure with Passive Damper - Part 2: Assessment of System Failure Probability (수동형 댐퍼를 장착한 구조물의 동적응답기반 신뢰성 해석 - 제2편: 시스템 파괴확률 산정)

  • Kim, Seung-Min;Ok, Seung-Yong
    • Journal of the Korean Society of Safety
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    • v.31 no.5
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    • pp.95-101
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    • 2016
  • This study proposes a multi-scale dynamic system reliability analysis of control system as a method of quantitative evaluation of its performance in probabilistic terms. In this second paper, we discuss the control effect of the viscous damper on the seismic performance of the structure-level failure. Since the failure of one structural member does not necessarily cause the collapse of the structural system, we need to consider a set of failure scenarios of the structural system and compute the sum of the failure probabilities of the failure scenarios where the statistical dependence between the failure scenarios should be taken into account. Therefore, this computation requires additional system reliability analysis. As a result, the proposed approach takes a hierarchial framework where the failure probability of a structural member is computed using a lower-scale system reliability with the union set of time-sequential member failures and their statistical dependence, and the failure probability of the structural system is again computed using a higher-scale system reliability with the member failure probabilities obtained by the lower-scale system reliability and their statistical dependence. Numerical results demonstrate that the proposed approach can provide an accurate and stable reliability assessment of the control performance of the viscous damper system on the system failure. Also, the parametric study of damper capacity on the seismic performance has been performed to demonstrate the applicability of the proposed approach through the probabilistic assessment of the seismic performance improvement of the damper system.

Analysis of the current status of quantitative literature evidence for the prescription of 56 herbal medicines covered by health insurance (건강보험 급여 한약제제 56종 처방의 계량적 문헌 근거 현황 분석)

  • Chul Kim;Hyeun-kyoo Shin
    • The Journal of Korean Medicine
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    • v.44 no.3
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    • pp.189-200
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    • 2023
  • Objectives: The purpose of this study is to analyze the current state of quantitative literature evidence for the prescription of 56 herbal medicines covered by health insurance that have been studied in Korea for the past 30 years, to evaluate the reliability of the evidence, and to find out the research direction of herbal medicine prescription in the future. Methods: 56 kinds of herbal medicine prescriptions were searched in domestic literature search databases OASIS, DBpia, and overseas PubMed, classified into chemistry, toxicity, cells, animals, clinical cases, and clinical trial studies, and built into an EBM pyramid structure. Results: When classified according to research contents, there were 61 cases (7.5%) of physicochemical analysis to identify constituent substances, 80 cases (9.8%) of toxicity evaluation, and 672 cases (82.7%) of efficacy evaluation. The efficacy evidence was classified according to the evidence-based medical pyramid structure: 196 cell trials (29.1%), 372 animal trials (55.4%), 89 case and case reporting series (13.3%), 7 comparative case studies (1.1%), and 8 randomized control clinical trials (1.2%). In the pyramid composition, the basis for the validity of 56 kinds of herbal medicines prescribed was 568 cases (84.5%) in cell and animal units, which could not be said to be highly reliable. There was no relationship between the ranking of quantitative literature evidence for herbal medicine prescriptions and the ranking of salary administration. Conclusions: In an era that continues to require scientific evidence for herbal medicine, traditional herbal medicine should secure the basis for safety validity even for the 10th most frequent prescription among 56 herbal medicine prescriptions for consumers. In particular, traditional herbal medicine should increase the quantitative and qualitative level of case reports on related herbal medicine prescriptions, focusing on each clinical society, and move toward comparative case studies and randomized clinical trial so that traditional herbal medicine is positioned as Evidence-based medicine.

A Study on the Outage Cost Assessment by using Macro Approach (거시적인 접근방법을 통한 공급지장비 추정에 관한 연구)

  • Park, Young-Shin;Jeon, Dong-Hoon;Park, Jeong-Je;Oh, Tae-Gon;Cho, Kyeong-Hee;Choi, Jae-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1703-1711
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    • 2010
  • Electric power utilities are facing increasing uncertainties regarding the economic, political, societal, environmental constraints under they operate and plan their future systems. The utilities have to integrate consumers' interruption cost representing reliability worth of electricity into the process of determining the optimum investment level. In order to do so, the estimated outage cost must be included into quantitative index corresponding to system capital and operation investment cost to establish an optimal expansion plan. This paper is a study on the outage cost assessment by using macro approach for calculating IEAR(Interrupted Energy Assessment Rates) and the TRELSS(Transmission Reliability Evaluation for Large-Scale Systems) program was used to calculate EENS(Expected Energy Not Served).

A Study on the Reliability Prediction for Space Systems (우주 시스템의 신뢰성 예측에 관한 연구)

  • Yu, Seung-U;Lee, Baek-Jun;Jin, Yeong-Gwon
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.227-239
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    • 2006
  • Reliability prediction provides a rational basis for design decisions such as the choice between alternative concepts, choice of part quality levels, derating factors to be applied, use of proven versus state-of-the-art techniques, and other factors. For this reasons, reliability prediction is essential functions in developing space systems. The worth of the quantitative expression lies in the information conveyed with the numerical value and the use which is made of that information and reliability prediction should be initiated early in the configuration definition stage to aid in the evaluation of the design and to provide a basis for item reliability allocation (apportionment) and establishing corrective action priorities. Reliability models and predictions are updated when there is a significant change in the item design availability of design details, environmental requirements, stress data, failure rate data, or service use profile. In this paper, the procedure, selection of reliability data and methods for space system reliability prediction is presented.

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Study on the Evaluation of Skill Level for Aircraft Body Assembly Workers (항공기 기체 조립 작업자 숙련도 평가 연구)

  • Hyoung Geun Kwon;Chie Hoon Song
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.3
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    • pp.535-546
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    • 2024
  • This research aims to develop a model to objectively and quantitatively measure the skill level of aircraft body assembly workers. Because aircraft body assembly is predominantly a manual process, skills management is a key factor of manufacturing competitiveness. Currently, skills management relies on the subjective judgment of supervisors, which lacks objectivity and reliability. As a remedy, this study proposed a systematic skill management model based on objective and quantitative evaluation criteria. By considering prior research, we developed an evaluation model that takes into account both expertise and versatility of a worker. The model selected five major tasks required for aircraft body assembly and established evaluation criteria considering the difficulty and maturity of each task. We then conducted a pilot evaluation with over 200 workers in four SMEs to validate the practicality and effectiveness of the model. Consequently, we identified and addressed the limitations of the existing evaluation method, subdivided the skill levels based on the performance capabilities of each task, and proposed a career growth path. The developed evaluation model offers critical data for executives and managers to determine work assignments, education, training, performance incentives, and wages. It is expected to enhance the attraction of new talent and systematize skills management in aviation manufacturing in the future.

A Service Selection Method using Trust Evaluation in QoS based Web Services Composition (QoS 기반 웹서비스 조합에서 신뢰성 평가를 통한 서비스 선택 기법)

  • Kim, Yu-Kyong;Ko, Byung-Sun
    • Journal of KIISE:Software and Applications
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    • v.36 no.1
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    • pp.1-9
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    • 2009
  • In heterogeneous and distributed computing environments, with an increasing number of Web services providing similar functionalities, the reliability of Web services is a critical decision factor. To fulfill the open business model such as cooperation among enterprises, several Web services can be composed into the upper level business transaction. In Web services composition, the reliability of services is more and more critical. Though each unit Web service can be reliable, the reliability of the composed service is not guaranteed. Thus a way to efficiently assess and select composed Web services is needed. In this paper, we define new metrics for measuring the trust value of Web services, and propose an evaluation method to predict the trustworthy degree of the composed services based on the metrics. We also define a conceptual framework to support optimal Web services selection based on the proposed trust evaluation method. By selecting using the quantitative measurement rather than intuitive selection of the service user, it allows the service users to select the high reliable service meeting their quality requirements well.