• 품질경영학회지
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• 제20권1호
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• pp.158-167
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• 1992

This paper represents the new techniques for optimal sampling plans of reliability applying the mathematical complex number(real and imaginary number) in the complex system of reliability. The research formulation represent a mathematical model Which preserves all essential aspects of the main and auxiliary factors of the research objectives. It is important to formule the problem in good agreement with the objective of the research considering the main and auxilary factors which affect the system performance. This model was repeatedly tested to determine the required statistical chatacteristics which in themselves determine the actual and standard distributions. The evaluation programs and techniques are developed for establishing criteria for sampling plans of reliability effectiveness, and the evaluation of system performance was based on the complex stochastic process(derived by the Runge-Kutta method. by kolmogorv's criterion and the transform of a solution to a Sturon-Liouville equation.) The special structure of this mathematical model is exploited to develop the optimal sampling plans of reliability in the complex system.

• 한국군사과학기술학회지
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• 제17권3호
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• pp.336-341
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• 2014

When using a higher-order modulation scheme, there are variations in bit-reliability depending on the bit position in a modulation symbol. Variations of bit-reliability in the codeword block lower the decoding performance. Also, the decoding performance increases as the sum of the bit-reliabilities in the codeword block increases. This paper presents a novel hybrid automatic repeat request scheme that increases the sum of the reliabilities of the transmitted bits by lowering the modulation order, and decreases the variations of bit-reliability in the codeword block by preferentially retransmitting bits with low reliability. The proposed scheme outperforms the constellation rearrangement scheme. Furthermore, the proposed scheme also provides a good solution in cases where the size of the retransmission block is smaller than the size of the initial transmission block.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.369-374
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• 2004

Web-based analysis programs for reliability assessment of machine tools were developed in this study. First, the reliability data analysis program was developed to search for failure rate using failure data and reliability test data of mechanical part. Second, failure mode analysis was developed through performance tests like circular movement test vibration test for machine tools. This analysis program shows correlation between failure mode and performance test result. Third, tool life was predicted by correlation between flank wear and cutting time, using the extended Taylor tool life equation in turning data and the equivalently converted equation in order to apply ball endmill data to Taylor tool life equation in milling data. All the information related to input and result data can be stored in theses programs.

• 한국농공학회지
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• 제45권2호
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• pp.35-44
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• 2003

A system reliability method is proposed to decide reliable serviceability of agricultural irrigation system. Even though reliability method is applied to real engineering situations involving actual life environments and maintaining costs, a number of Issues arise as a modeling and analysis level. This article use concepts that can be described the probability of failure with time variant and series-parallel system reliability analysis model. A proposed method use survivor function that can simulate a time-variant performance function for a lifetime before it is required essential maintenance or replacement to define a target probability of failure in agricultural irrigation canal. In the further study, it is required a relationship between a state of probability of failure and current serviceability to make the optimum repair strategy to maintain appropriate serviceability of an irrigation system.

• International Journal of Reliability and Applications
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• 제3권3호
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• pp.147-154
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• 2002

In this paper, we consider the warm standby redundant system(WSRS) which is consisted of an active unit, a standby unit and a switchover device. In addition, the switchover processing is controlled by a control module. The effect of failure of the control module is taken into account to develop our reliability model for the redundant structure. For the performance evaluation of a redundant system with the function of switchover processing which is assumed to cause the increase of the failure rate of the system, some reliability indices, such as availability, average availability, reliability and steady state availability, are considered.

• ETRI Journal
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• 제40권1호
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• pp.101-110
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• 2018

In wireless positioning systems using range measurements non-line-of-sight (NLOS) links cause estimation errors. Several studies have attempted to improve the positioning performance by mitigating these NLOS errors. These studies, however, have focused on the performance of a dataset consisting of three or more links. Therefore, measurement errors induced by links are averaged, and a reliable link is not fully utilized in the dataset. This paper proposes a Link Reliability based on Range Measurement (LRRM) scheme, which specifies the relative reliability of each link using residuals. The link reliability becomes the input to a Link Residual Weighting (LRW) scheme, which is also proposed as a weighted positioning scheme. Moreover, LRRM and LRW constitute new turbo positioning, where the estimation errors are reduced considerably by iterative updates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1513-1514
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• 2006

In this paper, there have been brief review about the important consideration in laboratory planning and construction of the artificial pollution testing facilities including 300 kV, 1800 kVA AC test system, which enable to lest and evaluate the UHV dielectric performance of power insulators up to transmission class. Also it is described simply about its trial running of the whole test system. To evaluate the performance characteristics against contamination for various power installation, especially for the insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.439-453
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• 2020

The purpose of this study is to investigate the impacts of business service quality on satisfaction, commitment, performance, and loyalty in higher education. A survey was given to undergraduates involved in business through employment and start-up companies at a private university in Korea. With 252 respondents, this study used exploratory factor analysis and reliability analysis to verify the reliability and validity of measured variables. Multiple regression was employed as a statistical method for the hypotheses of the study. The research questions were: 1) How do education SERVQUAL factors (tangibles, responsiveness, reliability, assurance, and empathy) affect customer satisfaction? 2) How do education SERVQUAL factors affect customer commitment? 3) How does customer satisfaction or commitment affect education performance? 4) How does customer satisfaction, commitment or performance affect their loyalty in higher education? The findings show that most dimensions of business service quality have effects on satisfaction and commitment, and satisfaction and commitment have a positive effect on performance. Additionally, satisfaction, commitment and performance all have an effect on loyalty. This study confirmed the need for the improvement of business service quality in a private university. Additionally, it highlighted the importance of user satisfaction, commitment and performance in order to increase the loyalty level of undergraduate students.

• 품질경영학회지
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• 제41권1호
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• pp.135-148
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• 2013

Purpose: This paper presents a method to evaluate the stockpile reliability of propelling charge for performance and storage safety with storage time. Methods: We consider a performance failure level is the amount of muzzle velocity drop which is the maximum allowed standard deviation multiplied by 6. The lifetime for performance is estimated by non-linear regression analysis. The state failure level is assumed that the content of stabilizer is below 0.2%. Because the degradation of stabilizer with storage time has both distribution of state and distribution of lifetime, it must be evaluated by stochastic process method such as gamma process. Results: It is estimated that the lifetime for performance is 59 years. The state distribution at each storage time can be shown from probability density function of degradation. It is estimated that the average lifetime as $B_{50}$ life is 33 years from cumulative failure distribution function curve. Conclusion: The lifetime for storage safety is shorter than for performance and we must consider both the lifetime for storage safety and the lifetime performance because of variation of degradation rate.

• 임상간호연구
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• 제16권3호
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• pp.5-23
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• 2010

Purpose: This study was conducted to determine the validity and reliability of performance measurement tools based on the nursing process for prevention and management of pressure ulcers, falls and pain. Methods: The performance measurement tools were reviewed by a panel of experts and refined on the basis of the panel's suggestions. The validity of the performance measurement tools was measured by surveying hospital nurses. The reliability of these tools was tested by having nursing experts use the tools in five nursing units to assess nursing performance in prevention and management of pressure ulcers, falls and pain. Results: The performance measurement tools in this study were found to be acceptable as tools to evaluate quality of nursing care in pressure ulcers, falls and pain. The reliability of the performance measurement tools was acceptable. Conclusion: These results indicate that the performance measurement tools developed in this study are valid and reliable instruments to monitor and improve quality of nursing care in prevention and management of pressure ulcers, falls and pain.