• 제목/요약/키워드: Technical Reliability

검색결과 755건 처리시간 0.027초

신뢰성 향상을 위한 40 발명원리의 활용 (40 Inventive Principles in Reliability Enhancement)

  • 정해성
    • 한국신뢰성학회지:신뢰성응용연구
    • /
    • 제12권4호
    • /
    • pp.239-253
    • /
    • 2012
  • The founder of TRIZ, Genrich Altshuller, discovered forty patterns of inventive solutions, known as 40 Inventive Principles, extracting them from tens of thousands of technical patents. It was found further that 40 Inventive Principles are applicable not only for every technical field, but also for non-technical spheres - finance, business, management, marketing, social relations, education and etc. This paper extends the area of reliability through TRIZ. Enclosed are several examples how 40 Inventive Principles have been used in the reliability enhancement in the literature.

Technical Performance of Two-Dimensional Shear Wave Elastography for Measuring Liver Stiffness: A Systematic Review and Meta-Analysis

  • Dong Wook Kim;Chong Hyun Suh;Kyung Won Kim;Junhee Pyo;Chan Park;Seung Chai Jung
    • Korean Journal of Radiology
    • /
    • 제20권6호
    • /
    • pp.880-893
    • /
    • 2019
  • Objective: To assess the technical performance of two-dimensional shear wave elastography (2D-SWE) for measuring liver stiffness. Materials and Methods: The Ovid-MEDLINE and EMBASE databases were searched for studies reporting the technical performance of 2D-SWE, including concerns with technical failures, unreliable measurements, interobserver reliability, and/or intraobserver reliability, published until June 30, 2018. The pooled proportion of technical failure and unreliable measurements was calculated using meta-analytic pooling via the random-effects model and inverse variance method for calculating weights. Subgroup analyses were performed to explore potential causes of heterogeneity. The pooled intraclass correlation coefficients (ICCs) for interobserver and intraobserver reliability were calculated using the Hedges-Olkin method with Fisher's Z transformation of the correlation coefficient. Results: The search yielded 34 articles. From 20 2D-SWE studies including 6196 patients, the pooled proportion of technical failure was 2.3% (95% confidence interval [CI], 1.3-3.9%). The pooled proportion of unreliable measurements from 20 studies including 6961 patients was 7.5% (95% CI, 4.7-11.7%). In the subgroup analyses, studies conducting more than three measurements showed fewer unreliable measurements than did those with three measurements or less, but no intergroup difference was found in technical failure. The pooled ICCs for interobserver reliability (from 10 studies including 517 patients) and intraobserver reliability (from 7 studies including 679 patients) were 0.87 (95% CI, 0.82-0.90) and 0.93 (95% CI, 0.89-0.95), respectively, suggesting good to excellent reliability. Conclusion: 2D-SWE shows good technical performance for assessing liver stiffness, with high technical success and reliability. Future studies should establish the quality criteria and optimal number of measurements.

무기체계획득단계에서의 RAM 달성을 위한 기술검토의 식별과 업무분장 (Identification and Task Allocation of Technical Reviews for Achieving RAM in Weapon System Acquisition Process)

  • 김명수;오근태;이동하
    • 한국신뢰성학회지:신뢰성응용연구
    • /
    • 제7권2호
    • /
    • pp.73-87
    • /
    • 2007
  • In this paper, based on the American weapon acquisition management framework in DoD Instruction 5000.2 "Operation of the Defence Acquisition System" and the contents of "DoD Guide for Achieving Reliability, Availability, and Maintainability" published by Defense Acquisition University, the kinds and roles of technical reviews are introduced and the identification of RAM related tasks which are performed at levels of technical reviews during acquisition process are considered. And the task allocations for developers, development managers, and users are proposed. Finally the relationships of acquisition management framework, technical reviews and RAM tasks are tabulated.

  • PDF

작업환경측정 신뢰성평가제도 개선방안에 관한 연구 (tudy on the Improvement of Reliability Assessment of Work Environment Measurement in Korea)

  • 황규석
    • 한국산업보건학회지
    • /
    • 제29권1호
    • /
    • pp.50-56
    • /
    • 2019
  • Objective: The aim of this study is to analyze the reliability assessment of work environment measurement, and to propose ways of improving the system. Methods: We have reviewed reports and articles on the reliability assessment written by KOSHA and academia in order to analyze problems related with the system and propose the alternatives. Results: There are three ways to improve the system of the reliability assessment. First of all, it is necessary to perform the reliability assessment by measuring the work environment when workers raise questions about the results so we can make workers trust these results of the reliability assessment. Secondly, we should inspect the workplace at first, not the work environment service provider, so we can increase the employer's recognition of his duty to practice the work environment measurement. Thirdly, the technical committee is needed for technical issues related with the work environment measurement. Conclusions: Above all, it is crucial to get the workers' interest and trust to improve the work environment measurement. The reliability assessment should support the meaning and value of the work environment measurement by practicing the reliability assessment whenever workers have a demand for this and operating the technical committee.

자이로의 신뢰성 예측모델에 관한 연구 (A Study on The Feliability Predication Model of Gyroscope)

  • 백순흠;문홍기;김호룡
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 1993년도 추계학술대회 논문집
    • /
    • pp.475-481
    • /
    • 1993
  • The objective of this study is to develope the reliability prediction model for Float Rated Integrating Gyroscope( :FRIG) at maximum loading. The equation of motion for FRIG is firstly derived to set up the reliability prediction model. To analysis reliability or all parts of the gyro is not easy due to their complicated structure. Therefore the failure parts are chosen by Failure Mode Effective Analysis (:FMEA). F.E.M is utilized to calculate loads for the selseced rotating assembly and pivot / jewel. The technical reliability is calculated by applying reliability design theory with these results and the performance reliability is sought through distribution estimation with error test data. The bulk reliability of gyroscope is sought by applying the two results. The present prediction results are compared with the accumulation time in good agreement.

  • PDF

Time-dependent analysis of cable trusses -Part II. Simulation-based reliability assessment

  • Kmet, S.;Tomko, M.;J., Brda
    • Structural Engineering and Mechanics
    • /
    • 제38권2호
    • /
    • pp.171-193
    • /
    • 2011
  • One of the possible alternatives of simulation-based time-dependent reliability assessment of pre-stressed biconcave and biconvex cable trusses, the Monte Carlo method, is applied in this paper. The influence of an excessive deflection of cable truss (caused by creep of cables and rheologic changes) on its time-dependent serviceability is investigated. Attention is given to the definition of the basic random variables and their statistical functions (basic, mutually dependent random variables such as the pre-stressing forces of the bottom and top cable, structural geometry, the Young's modulus of elasticity of the cables, and the independent variables, such as permanent load, wind, snow and thermal actions). Then, the determination of the response of the cable truss to the loading effects, and the definition of the limiting values considering serviceability of the structure are performed. The potential of the method, using direct Monte Carlo technique for simulation-based time-dependent reliability assessment as a powerful tool, is emphasized. Results obtained by the First order reliability method (FORM) are compared with those obtained by the Monte Carlo simulation technique.

Key Technical Challenges for Integrated Sensors in Power Electronics and Motor Drives

  • Lorenz, Robert D.
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
    • /
    • 제4B권4호
    • /
    • pp.170-179
    • /
    • 2004
  • The paper presents technical issues which integrated sensors must address to be implemented in the next generation of power electronics and motor drives. The underlying goal of the sensor integration will be to improve reliability of power conversion systems while making the power converter and motor drive become the primary source of diagnostic signals for the application. The paper focuses on design methodologies that will allow this integration to succeed in meeting the technical demands for both reliability and for application level diagnostics.

High Efficiency Thin Film Photovoltaic Device and Technical Evolution for Silicon Thin Film and Cu (In,Ga)(Se,S)

  • 신명훈
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
    • /
    • pp.88-88
    • /
    • 2012
  • High efficiency thin film photovoltaic device technology is reviewed. At present market situation, the industrial players of thin film technologies have to confront the great recession and need to change their market strategies and find technical alternatives again. Most recent technology trends and technical or industrial progress for Silicon thin film and CIGS are introduced and common interests for high efficiency and reliability are discussed.

  • PDF

설계변수의 변동 불확실성을 고려한 신뢰성 기반 최적설계 (Reliability-Based Design Optimization Considering Variable Uncertainty)

  • 임우철;장준용;김정호;나종호;이창근;김용석;이태희
    • 대한기계학회논문집A
    • /
    • 제38권6호
    • /
    • pp.649-653
    • /
    • 2014
  • 대부분의 신뢰성 기반 최적설계는 최적설계 과정에서 설계점이 이동함에도 불구하고 설계변수의 불확실성은 변하지 않는다. 하지만 실제 문제에서 설계변수의 값에 따라 불확실성이 변하는 경우가 있다. 예를 들어 철판의 두께가 설계변수이고, 철판의 제작공차가 불확실성인 경우, 철판의 두께에 따라 철판의 제작공차가 달라지기 때문에 설계변수의 값에 따라 그 값의 불확실성이 변한다. 본 연구에서는 설계변수의 값에 따라 불확실성이 변하는 것을 변동 불확실성으로 정의하고, 이를 신뢰성 기반 최적설계에 적용하는 변동 불확실성을 고려한 신뢰성 기반 최적설계 기법을 제안한다. 수학예제에서 변동 불확실성을 고려하지 않은 신뢰성 기반 최적설계와 변동 불확실성을 고려한 신뢰성 기반 최적설계의 비교를 통해 제안한 방법의 필요성을 확인한다. 또한 엔진 크래들의 변동 불확실성을 고려한 신뢰성 기반 최적설계를 통해 제안한 방법의 유용성을 확인한다.

Reliability analysis of tested steel I-beams with web openings

  • Bayramoglu, Guliz
    • Structural Engineering and Mechanics
    • /
    • 제41권5호
    • /
    • pp.575-589
    • /
    • 2012
  • This paper presents a reliability analysis of steel I-beams with rectangular web openings, based on a combination of the common probabilistic reliability methods, such as RSM, FORM and SORM and using data obtained from experimental tests performed at the Istanbul Technical University. A procedure is proposed to obtain the optimum design load that can be applied to this type of structural members, by taking into account specified target values of reliability indices for ultimate and serviceability limit states. The goal of the paper is to present an algorithm to obtain more realistic and economical design of beams and to demonstrate that it can be applied efficiently to steel I-beams with web openings. Finally, a sensitivity analysis is performed allowing to ranking the random variables according to their importance in the reliability analysis.