• Journal of Drive and Control
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• v.9 no.2
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• pp.22-27
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• 2012

In order to improve the life and reliability of fluid components used in the Automotive, Hydraulics and Aerospace industries, the cleanliness of the system parts and components before their assembly into the system is being addressed. The measurement of components and parts cleanliness is related to contaminant collection, analysis and data reporting and ISO Standards are continually being developed to control procedures. This Paper explains the processes in these standards and explains how similar procedures have been adapted to suit the requirements of the above Industries. It also gives guidance and recommendations on the implementation of these standards, so that the best use can be made of them.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.153-166
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• 1996

It is important to make use of the scrapped materials, components, and subassemblies which have still high quality and reliability in an out of service cars from the view point of economy and environment. In this paper, we studied geometrical and material characteristics of parte, subassemblies and joining elements to be assembled in designing a car. The mechanism of disassembly between parts and subassemblies is analyzed in order to disassemble recyclable parts in a scrapped automobile. The weak points of disassembly process are analyzed and the parameters for disassemblability are defined. And the guidelines for disassemblability are developed.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.126-131
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• 2010

In order to improve the life and reliability of fluid components used in the Automotive, Hydraulics and Aerospace industries, the cleanliness of the system parts and components before their assembly into the system is being addressed. The measurement of components and parts cleanliness is related to contaminant collection, analysis and data reporting and ISO Standard are continually being developed to control procedures. This Paper explains the processes in these standards and explains how similar procedures have been adapted to suit the requirements of the respective Industry. It also gives guidance and recommendations on the implementation of these standards, so that best use can be made of them.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.5
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• pp.43-51
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• 2008

Generally a plastic injection molding is a manufacturing process used to produce the various parts of complicated shape at low cost. The objective of this study is to implement a new plastic injection molding process with inserted Aluminum sheet, which is highly durable, light and luminous. Moldflow analysis and simulation of plastic injection molding process with inserted Aluminum sheet were carried out in order to predict optimal molding operation conditions. The experimental results in the Al-inserted plastic injection molding process were compared with the simulation results by Moldflow. Durability and reliability test results for trial products were satisfied to adopt the Al-inserted plastic injection molding process developed as manufacturing of automobile interior parts.

• Journal of Korean Society for Quality Management
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• v.46 no.2
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• pp.193-210
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• 2018

Purpose: The purpose of this study is to escape from the existing defense quality policy focused on government-led quality assurance for mass-produced items and to secure quality reliability of weapon systems through a defense quality policy paradigm shift based on designing a verification systems anchored on reliability through the enhancement of military supply quality control in the development stage, the enhancement of quality responsibility of the manufacturing contractor and other methods. Methods: For the shift to the quality-based defense quality policy, the status and the problems of the status quo are analyzed and the direction of future defense quality policy is suggested based on literature review of the concept of reliability and reliability in the field of defense, on case studies of global corporations and their quality policies, on the background on quality assurance in defense, and on case studies of quality policies in other government organizations, Results: Based on the case studies of quality policies in global corporations and other government agencies, the importance of preventive quality control from the early development stages, quality control based on the reliability of the materials and parts, and shift of the quality policy to a certification system to achieve these objectives were highlighted. Conclusion: To secure reliability of weapon system quality, the quality policy must be shifted to a system focused on reliability-based design and verification and there is a further need to enhance the operational efficiency and capacity of DTaQ based on studies and evaluation of weapon system reliability.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.323-329
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• 2002

This paper proposes a frame reliability weighting method to compensate for a time-selective noise that occurs at random positions of speech signal contaminating certain parts of the speech signal. Speech frames have different degrees of reliability and the reliability is proportional to SNR (signal-to noise ratio). While it is feasible to estimate frame Sl? by using the noise information from non-speech interval under a stationary noisy situation, it is difficult to obtain noise spectrum for a time-selective noise. Therefore, we used statistical models of clean speech for the estimation of the frame reliability. The proposed MFR (model-based frame reliability) approximates frame SNR values using filterbank energy vectors that are obtained by the inverse transformation of input MFCC (mal-frequency cepstral coefficient) vectors and mean vectors of a reference model. Experiments on various burnt noises revealed that the proposed method could represent the frame reliability effectively. We could improve the recognition performance by using MFR values as weighting factors at the likelihood calculation step.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.148-153
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• 2002

사후봉사의 핵심은 신속한 고장 수리와 원활한 부품 공급이다. 일정 지역을 담당하고 있는 사후봉사 업소가 보유해야 할 수리 부품에 대한 적정 재고량 산정은 사후봉사 업소의 안정적인 경영뿐만 아니라 원활한 사후봉사의 기능을 위해서도 대단히 중요한 일이다. (중략)

• Journal of Nutrition and Health
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• v.42 no.4
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• pp.374-385
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• 2009

This study aims to develop an index of food security in order to assess food security status in Korea and to evaluate reliability and validity of the index. The index of food security was developed based on the US Household Food Security Survey Module (US-HFSS). After the US-HFSS was translated and back-translated, it was evaluated and modified by a focus interview for experts. The developed Korean Household Food Security Survey Module (K-HFSS) was tested by cognitive interviews and a pretest for general community population to assess its application for Korean population. For the reliability and validity of K-HFSS, the survey was conducted with 300 adults aged 40 years or more living in a rural community and 212 infants and toddlers living in an urban community. The reliability was assessed by Cronbach' alpha and the validity was evaluated by content validity, construct validity, and criterion-related validity. The questionnaire items of K-HFSS were partly modified, accounting for Korean social and cultural backgrounds and adapted by general community population. The reliability was relatively high, showing Cronbach' alpha coefficients ranged from 0.80 (for adults) to 0.87 (for infants and toddlers). The content and construct validities were all acceptable. The result of criterion-related validity showed that food security status was significantly related to the household income level. In conclusion, the K-HFSS would be used as a reliable and valid instrument to assess food security status in parts of the Korean population.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.63-68
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• 2006

This research presents the reliability analysis of the pneumatic actuator within the tape feeder that is used to transfer the correct force to linked parts during l.0E+7 cycles. First, the degradation analysis for thrust and air leakage is executed to obtain the failure data of a product based on its performance over time. Second, once the parameters has been calculated using the weibull 2-parameter distribution and MLE(Maximum Likelihood Estimation), information related to life such as reliability, failure rate, probability density function is estimated. Finally, MTTF(Mean Time To Failure) and $B_{10}$ life of actuators are calculated. MTTF means the mean life at the confidence level and $B_{10}$ life refers to the time by which 10% of the product would fail. In this study, failure causes and solutions are examined using the reliability analysis.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.27-33
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• 2013

In this study, the FMEA and FTA for reliability analysis of hybrid rocket motor are performed, that was designed in the Hybrid Rocket Propulsion Laboratory of Korea Aerospace University. In order to carry out these analyses the structure of the hybrid rocket motor is hierarchically divided into 36 parts down to the component level and FMEA is carried out with 72 failure modes. Reliability is assessed based on the FMEA, and the results are used in the FTA to evaluate the overall system reliability. In the FMEA, the relationship between the cause and failure modes, effects and their risk priorities are evaluated qualitatively. 27 failure modes are chosen as those with the critical severity that should be improved with priority. As a result of the FMEA / FTA study, a series of design or material changes are made for the improvement of reliability.