• 한국전문물리치료학회지
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• 제3권3호
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• pp.24-31
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• 1996

Manual dextrity is frequently evaluated in rehabilitation to estimate hand function. The Box and Block Test(BBT) mearsures gross manual dextrity. The first goal of this study was to verify the test-retest reliability of the BBT for 4, 5 years old children. The second goal of this reserch was to develop normative data from 35 convenient sample of normal children. The results showed the test-retest reliability was high (Pearson product moment correlation coefficients of 0.71 to 0.82).

• 한국전문물리치료학회지
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• 제17권4호
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• pp.49-54
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• 2010

The reliability of the thickness measurement of the lumbar multifidus (LMD using real-time ultrasonography (US) was determined in only the superficial fiber of the lumbar multifidus (SM). However, previous studies have not examined the reliability of the deep fiber of the LM (DM). The purpose of this study was to determine the intrarater and the interrater reliability of the thickness measurements of DM using US. Eleven heathy males participated in the study. The thickness of the DM was measured with an US in the prone position. Reliability was examined using intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and the Bland and Altman plot. ICC(3,1) was used to calculate the interrater reliability of the thickness measurement of DM using the values from both the first and second test sessions. Additionally, ICC(3,1) was used to calculate the intrarater reliability of the measurements over two days using the measurements obtained in test session 1 and lest session 2. The results of this study were as follows: 1) the ICC(3,1) value for interrater reliability was .94 in the first test session, and .93 in the second test session. 2) the ICC(3,1) values for intrarater reliability of the measurements over two days was .90 in both the first examiner and the second examiner. The interrater reliability and interrater reliability of the DM measurements, obtained via the US protocol used in this research was excellent. Therefore, we conclude that the thickness measurement of the DM obtaioned from the US protocol used in this research would be useful for clinician assessment of the thickness of the DM.

• 대한임베디드공학회논문지
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• 제13권4호
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• pp.205-214
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• 2018

The reliability test is a crucial step for ensuring robustness of high-cost and complex weapon systems. In this paper, we present a set of quantitative criteria to select critical parts or components in weapon systems for the reliability test, and implement a fuzzy inference system by applying developed criteria to fuzzy theory. We classify the selection criteria of critical parts or components into four fuzzy sets and membership functions. A fuzzy inference rule is proposed based on the AHP (Analytic Hierarchy Process) analysis technique so as to derive a convincing reliability test. The credibility of the fuzzy inference system is confirmed through a case study using actual equipment data exacted from an existent weapon system.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.170-175
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• 2015

Reliability demonstration tests (RDT's) are widely employed in design verification and process validation stages of industry. New mixed attribute-variable RDT plans that compromise demerits of the corresponding zero and zero or one failure plans which are common in practice are developed for the exponential distribution. The proposed mixed plans are compared with the typical RDT plans in terms of probability of acceptance and expected test termination time. A numerical example is provided to illustrate the mixed plans and a procedure to extend these plans to the Weibull distribution with known shape parameter is also presented.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권4호
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• pp.319-329
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• 2009

The airbag module is an inflatable restraint system that inflates within 0.05 seconds automatically in a collision to protect the occupants. The airbag fabrics used in the module are required to have the good resilience and strength and also to have retained at least 80% of mechanical properties after using longer than 10 years. In this study, we develop an accelerated test method in order to predict the lifetimes of airbag. In this test, we select temperature and humidity as environmental stresses by analyzing the failure mechanisms of coated and uncoated nylon 66 fabrics. It is found that the degradation of airbag fabrics is effectively accelerated under the combined conditions of high temperature and humidity. Analyzing the results of the accelerated test, the lifetimes of airbag fabrics are predicted to be longer than 10 years.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권1호
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• pp.55-63
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• 2013

For a reliability assessment of large machinery parts, reliable data should be obtained from testing many samples for a long time. However, in case of testing these samples, testing cost is excessive; in case of life test for long time, power consumption is high; and in case of accelerated test by over load, very high cost is required to build the life testing device. Especially it is very frequent that the expensive device's life has ended during a accelerated test by over load. In this study, the design mechanism of the life testing device which excels in energy saving during the reliability test of large machinery parts has been introduced.

• 소성∙가공
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• 제13권3호
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• pp.242-247
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• 2004

Literature review on reliability test method for developing high performance optical/thermofluidic components. Since the miniaturization by the conventional mechanical process is limited to milli-structure, i.e. $10^{-3}m$, new technology for fabricating of mechanical components is needed to match cost, reliability, and integrability criteria of micro-structure. Although numbers of various researches on MEMS/MOEMS devices and components, including material characterization, design and optimization, system validation, etc., the lack of standards and specifications make the researches and developments difficult. For that reason, this paper is intended to propose the methods of reliability test for measuring the mechanical property of optical/ thermofluidic components.

• International Journal of Reliability and Applications
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• 제2권4호
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• pp.269-280
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• 2001

The objective of this paper is to provide a model for effective implementation of costing RAM management in the design and procurement of production facility considering the system cost-performance trade-off. This research proposes a two-step approach of costing RAM design and test of system RAM for production facility. In Step 1, a static model is proposed to find an initial system configuration to meet the required performance based on system RAM and LCC and analyzes the trade-off relationships between various factors of RAM and LCC. In the second Step, we developed time and failure truncated models for system reliability test and analysis. For the computational purpose, we developed computer programs and have shown the sample results. By the sample test run, the proposed model has shown the possibilities to provide a good method to analyze system performance evaluation for both design and operational phase, This model can be applied to a wide variety of systems not only for costing RAM of the production facilities but also for the other kinds of equipment.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.207-212
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• 2017

Purpose: This article provides an efficient cushion molding method for improving reliability of the rotation driving system. Method: Allowable stress level for cushion is calculated by using physical characteristics of the rotation driving system. In addition, various test units are manufactured and used to conduct the rebound resilience, the burst pressure and the alternating load test. Results: Actual allowable stress level and test results of the rebound resilience, the burst pressure and the alternating load test are provided. Conclusion: The cushion manufactured by the compression molding method gives more preferable characteristics for improving the reliability of the rotation driving system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.84-86
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• 2005

The digital systems such as PLC or DCS have been applied to non-safety systems of nuclear power plants because of many difficulties in using analog systems. Nowadays, digital systems have been applied to safety systems of the plants such as reactor protection system. One of the main advantages of digital systems is applicability of automatic testing methods to the systems. The protection system requires high-reliability and high-availability because it shall minimize the propagation of abnormal or accident conditions of nuclear power plants. The calculation of reliability and availability of systems depends on the maintenance period of the system. In general, the maintenance period of the protection system is one-month in case of the manual test. However, the cycle of test can be shortened in several hours by using automatic periodic testing. The reliability and availability of the system is better when test period is shortened because the reliability and availability is inverse proportion to the test period. In this research, we developed the automatic periodic testing method for KNICS Reactor Protection System, which can test the system automatically without an operator or a tester. The automatic testing contained all functions of reaction protection systems from analog-to-digital conversion function of the bistable Processor to the coincident trip function of the coincident processor. By applying the automatic periodic testing to reaction system, the maintenance cost can be cut down and the reliability can be increased.