• 제목/요약/키워드: Reliability Study

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Intra- and Inter-Rater Reliability of Thickness Measurement of the Psoas Major Muscle Using the Spring Gauge Technique for the Consistent Inward Pressures on Healthy Subjects: An Ultrasonographic Study

  • Jeon, In-Cheol;Kim, Yong-Wook;Choung, Sung-Dae
    • 한국전문물리치료학회지
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    • 제20권4호
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    • pp.65-72
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    • 2013
  • The purpose of the current study was to determine the intra- and inter-rater reliability of muscle thickness (MT) measurement of the psoas major (PM) using ultrasonography (US) conducted at different inward pressures of approximately .5 kg, 1.0 kg, 1.5 kg, and 2.0 kg. Twelve healthy male subjects were recruited for the study. The thicknesses of both PMs of each subject were measured by two different examiners in a random manner to assess the intra- and inter-rater reliability. The measurement values were analyzed using the intra-class correlation coefficient (ICC) with a 95% confidence interval (CI). ICC (2,1) was used to determine the inter-rater reliability and ICC (3,1) was used to assess the intra-rater reliability of the MT measurement of the PM. The results indicated higher ICC values for intra-rater reliability compared to inter-rater reliability. In addition, the value for intra-rater reliability with .5 kg inward pressure [ICC=.99 (95%CI=.98~.99)] was higher compared to 1.0 kg, 1.5 kg, and 2.0 kg. Other inward pressures for intra- and inter-rater reliability in current study were also demonstrated to have excellent values (ICC=.94~.99). These findings showed that maintaining consistent inward pressure is essential for maintaining reliability of the results when the MT of the PM is measured by different examiners in a clinical setting.

Reliability assessment of semi-active control of structures with MR damper

  • Hadidi, Ali;Azar, Bahman Farahmand;Shirgir, Sina
    • Earthquakes and Structures
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    • 제17권2호
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    • pp.131-141
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    • 2019
  • Structural control systems have uncertainties in their structural parameters and control devices which by using reliability analysis, uncertainty can be modeled. In this paper, reliability of controlled structures equipped with semi-active Magneto-Rheological (MR) dampers is investigated. For this purpose, at first, the effect of the structural parameters and damper parameters on the reliability of the seismic responses are evaluated. Then, the reliability of MR damper force is considered for expected levels of performance. For sensitivity analysis of the parameters exist in Bouc- Wen model for predicting the damper force, the importance vector is utilized. The improved first-order reliability method (FORM), is used to reliability analysis. As a case study, an 11-story shear building equipped with 3 MR dampers is selected and numerically obtained experimental data of a 1000 kN MR damper is assumed to study the reliability of the MR damper performance for expected levels. The results show that the standard deviation of random variables affects structural reliability as an uncertainty factor. Thus, the effect of uncertainty existed in the structural model parameters on the reliability of the structure is more than the uncertainty in the damper parameters. Also, the reliability analysis of the MR damper performance show that to achieve the highest levels of nominal capacity of the damper, the probability of failure is greatly increased. Furthermore, by using sensitivity analysis, the Bouc-Wen model parameters which have great importance in predicting damper force can be identified.

A Study on the Reliability Evaluation of a Transmission System

  • Seungpil Moon;Jinboo Choo;Kim, Kyeongho;Donghoon Jeon;Park, Jaeseok
    • KIEE International Transactions on Power Engineering
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    • 제3A권3호
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    • pp.119-123
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    • 2003
  • Successful operation of power systems under the deregulated electricity market depends on the management of the transmission system reliability. Quantitative evaluation of the transmission system reliability is an important issue. Particularly, the nodal reliability indices can be of value in the management and control of congestion and reliability of the transmission system under the deregulated electricity market. In this study, a method developed for the reliability evaluation of the transmission system is presented. The Monte Carlo methods are used because of their flexibility when complex operating conditions are being considered. The usefulness and effectiveness of the proposed method are illustrated by a case study with the KEPCO system.

저수지 용수공급량에 따른 신뢰도 지표인자의 상관관계 해석 (A Study of Reliability Index Correlation Analysis in Reservoir Water-supply)

  • 박기범
    • 한국환경과학회지
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    • 제14권3호
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    • pp.289-296
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    • 2005
  • In this study aims is water supply criteria relations for evaluating the possible performance of water resources systems. These measures describe how likely a systems is to fail(reliability), how quickly it recovers from failure(resiliency), and how severe the consequences of failure may be(vulnerability). The performance of a criteria evaluating with a variety of operating policies illustrates their use. As a result study frequency reliability and quantitative reliability is linear relations and quantitative reliability is high reliability for equality water supply policy. As reliability and vulnerability are in inverse proportion to each other. Therefore these criteria relation analysis can be for Imha dam to variety water supply policy.

A Study on the Reliability and Validity of Measuring the Range of Motion of the Elbow Joint Using a Smartphone Application

  • Lee, Jun Cheol
    • International Journal of Internet, Broadcasting and Communication
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    • 제10권3호
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    • pp.65-72
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    • 2018
  • The purpose of this study was to assess the intra-tester and inter-tester reliability and validity of elbow flexion range of motion using a smart phone used by the general public. Thirty-one general people participated in this study. The range of motion in active elbow flexion was measured with a goniometer and smart phone over two times by two observers. The intra-taster and inter-tester reliability were evaluated using the intraclass correlation coefficient(ICC). The validity was measured by Pearson's correlation coefficient. The intra-observer reliability was good in all measured items ICC>0.900. The inter-observer reliability was high with ICC>0.806. All correlation coefficients of android app and goniometer were greater than 0.868 and showed a significant positive correlation (p<0.01). The range of motion measurement with a smart phone showed acceptable reliability. Therefore, using a smartphone to measure the range of motion of the elbow joint could provide convenience and economic benefits.

항공기 개발단계에서의 신뢰도 예측 정확도 향상에 관한 사례연구 (Case Study on Improvement of Reliability Prediction Accuracy in Development Phase for Aircraft)

  • 김영일;변광식;김한태
    • 한국항공운항학회지
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    • 제17권4호
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    • pp.25-31
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    • 2009
  • In development phase of the Aircraft Systems, the reliability prediction of electronic equipments are usually performed using MIL-HDBK-217. The reliability of fielded electronic systems, however, used to be underestimated with MIL-HDBK-217. To solve this problem, some alternatives are suggested and Telcordia SR-332 is among them. In this case study, the reliability of ESU which controls gas turbine engine is predicted using Telcordia SR-332 along with the development test data. The predicted reliabilities of ESU using Telcordia SR-332 and MIL-HDBK-217 are also compared. As a result this case study showed that the predicted reliability using Telcordia SR-332 was better close to field(operation) reliability than MIL-HDBK-217.

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민간 신뢰성기술의 국방분야 활용방안 (Application of Industrial Reliability Technology to Nation Defense Field)

  • 송병석;조재립
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제8권2호
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    • pp.61-73
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    • 2008
  • Reliability program in one of the most efficient tools for cost saving during the acquisition process including alternatives for design configurations, operation concepts, maintenance concepts. Industrial reliability centers have already equipped with infrastructure such as reliability standards, reliability apparatus. In this study revitalizing plans are proposed to apply industrial reliability technology to national defense technology.

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기동/화력 장비 신뢰도 성장모형 적용 사례 (A Study on Reliability Program of the Armed Vehicles)

  • 이창희;구융서;홍현의;정일호;박두일;김상부
    • 품질경영학회지
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    • 제44권3호
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    • pp.565-574
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    • 2016
  • Purpose: In this study, A reliability assurance model (or reliability program) is proposed to evaluate the reliability of an armed vehicle. The reliability assurance is performed through the reliability-centered activities in the K-000(armed vehicle) of D-Company Methods: By reflecting the current situations of korea defense industry, a reliability assurance model is built up based on the benchmarking results of world leading companies' best practices in same fields. So The reliability growth model is applied the Crow-AMSAA model Results: This research analysis the K-000(armed vehicle) of D-Company using the DT and OT failure data. and application case study by growth model of armed vehicles Conclusion: This research is result of application case study by growth model of armed vehicles.

환경물질을 제외한 전자부품의 신뢰성평가 방법 연구 -Pb와 Br을 제거한 PWB를 중심으로- (Reliability Assessment Methods for Electronic Component Removed Environmental Materials - focused on Printed Wiring Board without Pb and Br -)

  • 이종범;조재립
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제5권2호
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    • pp.241-259
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    • 2005
  • The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

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The reliability of an easy measuring method for abutment convergence angle with a computer-aided design (CAD) system

  • Seo, Yong-Joon;Kwon, Taek-Ka;Han, Jung-Suk;Lee, Jai-Bong;Kim, Sung-Hun;Yeo, In-Sung
    • The Journal of Advanced Prosthodontics
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    • 제6권3호
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    • pp.185-193
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    • 2014
  • PURPOSE. The purpose of this study was to evaluate the intra-rater reliability and inter-rater reliability of three different methods using a drawing protractor, a digital protractor after tracing, and a CAD system. MATERIALS AND METHODS. Twenty-four artificial abutments that had been prepared by dental students were used in this study. Three dental students measured the convergence angles by each method three times. Bland-Altman plots were applied to examine the overall reliability by comparing the traditional tracing method with a new method using the CAD system. Intraclass Correlation Coefficients (ICC) evaluated intra-rater reliability and inter-rater reliability. RESULTS. All three methods exhibited high intra-rater and inter-rater reliability (ICC>0.80, P<.05). Measurements with the CAD system showed the highest intra-rater reliability. In addition, it showed improved inter-rater reliability compared with the traditional tracing methods. CONCLUSION. Based on the results of this study, the CAD system may be an easy and reliable tool for measuring the abutment convergence angle.