• 한국치위생학회지
• /
• 제13권5호
• /
• pp.713-726
• /
• 2013

Objectives : The purpose of this study is to develop a job performance assessment tool for dental hygienists. Methods : The development consisted of three steps. The first step was to construct the contents of the assessment tool and a pretest questionnaire. In the second step, validity and reliability tests were done and modified for the pretest questionnaires and an assessment tool was made. The third step was verification of the assessment tool. A total of 678 data from the dental hygienists were analyzed to verify the validity and reliability. The assessment tool consisted of two areas such as job performance and competency/attitude: the job performance area covered four sub-areas including oral health education, preventive dental care, assistance for dental treatment, and administrative management. Results : The number of questions and reliability test result for each sub-area were as follows. Reliability coefficient for oral health education (10 questions) was 0.899, preventive dental care (8 questions) was 0.861, assistance for dental treatment (18 questions) was 0.915, administrative management (8 questions) was 0.919, competency of dental hygienists (11 questions) was 0.947, and attitude of dental hygienists (15 questions) was 0.955. Cronbach ${\alpha}$ coefficient for reliability of total 70 questions of the assessment tool was 0.980. Conclusions : The validity of the assessment tool was verified by three steps and the reliability proved to be significant. Consequently the assessment tool was found to be useful as an objective and valid job performance assessment tool for the dental hygienists.

• 대한기계학회논문집A
• /
• 제29권8호
• /
• pp.1102-1108
• /
• 2005

The integrity of nuclear piping systems has to be maintained sufficiently all the times during operation. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis, etc, are required. Up to now, the integrity assessment has been performed using conventional deterministic approach even though there are lots of uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for piping system evaluation. The objectives of this paper are to develop a probabilistic assessment program using reliability index and simulation technique and to estimate the damage probability of wall-thinned pipes in secondary systems. The probabilistic assessment program consists of three evaluation modules which are first order reliability method, second order reliability method and Monte Carlo simulation method. The developed program has been applied to evaluate damage probabilities of wall-thinned pipes subjected to internal pressure, global bending moment and combined loading. The sensitivity analysis results as well as prototypal evaluation results showed a promising applicability of the probabilistic integrity assessment program.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제11권1호
• /
• pp.17-30
• /
• 2011

Many domestic manufacturers make reflectors for Lamps of BLU(back light units). However, color change and parting occur as a result of diverse usage environment. Therefore, many of the manufacturers are reluctant in R&D investment of reflectors for Lamps of BLU. Hence, in this article reliability assessment criteria for reflector for lamp of BLU are established in terms of performance test, environment test and life test.

• 대한안전경영과학회지
• /
• 제9권6호
• /
• pp.55-68
• /
• 2007

Recently, all kind of 21C-typed electronic goods show the tendency of hightechnology and digital convergence rapidly. Also, failure mechanism which differs from original goods concept presents. Today, failure mechanism which differs from one that was happened by restricted harmful environment material before adapted the raw of environment material is changing the paradigm of reliability engineering. Thus, when applied the environment matter of original and secondary material at the electronic goods were removed, reliability assessment method and prediction stay into low level. This study suggests as solution to overcome these phenomenon. The study on the management method of environmental restriction substances which is recognized as important element in the reliability assessment about environment material of electronic goods and the study on reliability assessment method of PWB without environment material are progressed.

• 대한기계학회논문집A
• /
• 제37권9호
• /
• pp.1169-1174
• /
• 2013

대부분의 제품은 다수의 고장모드를 가지지만, 일반적으로 신뢰성 분석에서 고장모드 별로 분석하는 경우는 많지 않다. 또는 신뢰성 분석 시 고장모드에 대한 정보를 제공하지 않거나 대표적인 고장모드로 분석하기도 한다. 특히 신뢰성 인증시험에서 가정하고 있는 형상모수는 제품의 형상모수보다는 고장모드에 대한 형상모수 값이 더 중요하다. 본 연구에서는 다수의 고장모드를 가지는 기계부품에 대한 신뢰성 분석방법으로 경쟁 고장모드 분석방법과 혼합 와이블 분석방법을 소개한다. 그리고 3 가지 고장모드를 가지는 공기압 실린더의 사례에 대해 각 고장모드 별로 형상모수를 구하였으며, 3 가지 고장모드를 고려했을 때와 하나의 고장모드로 가정했을 때의 신뢰성 측도($B_{10}$ 수명, 특성 수명)을 비교하였다.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2005년도 춘계학술대회 논문집
• /
• pp.24-29
• /
• 2005

Fm (Focused ion beam) system is one of the most important equipments for the nano-scale machining. Various researches have been performed, since it can etch the material and deposit 3-D structure with high-aspect-ratio in the nanometer scale. In spite of those researches, the definite method for the reliability of FIB system has not been reported. In this paper, we proposed the reliability assessment method through nano-pattern fabrication. In the fabricated nano-pattern, the characteristics of FIB system are included. Using this effect, we tried to assess the FIB reliability. First, we suggested reliability assessment items and nano-patterns. And, to know the suitableness of the proposed method, we fabricated several nano-patterns using Nova200(FEI Company) and SMI2050(SEIKO) which are FIB apparatuses. The fabricated nano-patterns are measured with SEM (Scanning Electron Microscope) and compared with designed dimensions. And the compared results showed that the proposed method is suitable for the assessment of FIB system reliability.

• 드라이브 ㆍ 컨트롤
• /
• 제15권4호
• /
• pp.23-29
• /
• 2018

The objective of this paper is to evaluate the reliability of a volute pump and presents test results through performance and life tests. The performance and life test methods were presented by analyzing the failure modes of the volute pump. Zero failure test time was calculated to evaluate the reliability of the volute pump and then, the test was performed under accelerated conditions. The test was also carried out to check the failure modes of the field conditions. This study can be provided to improve the product reliability through failure analysis of the volute pump. And failure cause of typical failure case has been investigated and improvement design has been presented. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the volute pump.

• 대한물리의학회지
• /
• 제12권4호
• /
• pp.139-146
• /
• 2017

PURPOSE: The purpose of this study was to systematically analyze the reliability and validity of the Korean-version of the balance assessment tools. METHODS: Two reviewers of this study independently evaluated the titles of articles and abstracts of studies published until December 2016 through electronic databases (RISS, NDSL, KISS, DBpia) using the keywords "Balance or posture or postural control or postural stability", "Test or assessment or measurement or outcome measure or assessment tool or measurement tool", "Korean version", "Reliability" and "Validity". Regarding the questions considered suitable for the purpose of this study, consensus was reached after reading the full text. Selecting journals suitable for the purpose of the study, they were analyzed as data. RESULTS: The reviewers selected nine papers suitable for the purpose of this study, and Korean-version of the balance assessment tools, included the Berg Balance Scale (BBS), Activities-specific Balance Confidence (ABC) scale, Postural Assessment Scale for Stroke (PASS), Motor Assessment Scale (MAS), Trunk Impairment Scale (TIS), Falls Efficacy Scale (FES), Tinetti-Balance scale, Fullerton Advanced Balance (FAB) scale, and Function In Sitting Test (FIST). Our study showed that the reliability and validity of the Korean-version of the balance assessment tools were high. CONCLUSION: The Korean-version of the balance assessment tools with high reliability and validity would enable physical therapists to make a more accurate evaluation of balance.

• Smart Structures and Systems
• /
• 제16권2호
• /
• pp.367-382
• /
• 2015

This paper aims to conduct the reliability-based assessment of the welded joint in the orthotropic steel bridge deck by use of a mesh-insensitive structural stress (MISS) method, which is an effective numerical procedure to determine the reliable stress distribution adjacent to the weld toe. Both the solid element model and the shell element model are first established to investigate the sensitivity of the element size and the element type in calculating the structural stress under different loading scenarios. In order to achieve realistic condition assessment of the welded joint, the probabilistic approach based on the structural reliability theory is adopted to derive the reliability index and the failure probability by taking into account the uncertainties inherent in the material properties and load conditions. The limit state function is formulated in terms of the structural resistance of the material and the load effect which is described by the structural stress obtained by the MISS method. The reliability index is computed by use of the first-order reliability method (FORM), and compared with a target reliability index to facilitate the safety assessment. The results achieved from this study reveal that the calculation of the structural stress using the MISS method is insensitive to the element size and the element type, and the obtained structural stress results serve as a reliable basis for structural reliability analysis.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제5권2호
• /
• pp.241-259
• /
• 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.