• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.728-732
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• 2010

GIS(Gas insulated switching gear) is power equipment with excellent dielectric strength and is economy merit in high confidence and stability. Recently, because equipment of GIS was occurring problem of confidence used for a long time, partial discharge on-line diagnosis systems have been importantly recognized. Partial discharge (PD) detection is an effective means for monitoring and evaluation of dielectric condition of gas insulated system (GIS). The ultra-high-frequency (UHF) PD detection technique can detect and locate the PD sources inside GIS by detecting electromagnetic wave emitted from PD source. Therefore, real-time diagnostic system using UHF detection method has been developed for this application is being expanded gradually. However, the signal of partial discharge occurring in SF6 gas is very weak and susceptible to external noises which mainly consist of PD in air. Thus, it is important to distinguish the PD in SF6 gas more sensitively from the external noises. Unfortunately, these external noise signals and the partial discharge signals have very similar characteristics. Therefore, to solve this problem, we need the signal processing method for distinguish partial discharge signals with external noise signals for improvement of SNR(signal to noise ratio) and sensitivity. In this paper, we proposed internal signal processing method for removing external noise signals with built-in pre.amplifier and frequency conversion circuit.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.1
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• pp.99-105
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• 2018

PURPOSE: The aim of this study was to evaluate the concurrent validity and clinical usefulness of the universal plastic goniometer to measure the range of motion of the internal and external rotation of the hip joint using the three dimensional motion analysis which can analyze the joints and segment movements in the most objective and quantitative method. METHODS: Clinical and kinematic data were collected from thirty individuals using a universal plastic goniometer and a ten camera motion analysis system. Passive hip rotation range was obtained three trials for left and right hip joints using two measure methods simultaneously. RESULTS: There were significant differences between all matching measures of the two measures of internal and external rotation of the hip joint (p<.05). The relationship between the two tests for all measurements of the internal and external rotation of the hip was statistically significant with correlation coefficient form r=.87 to .96. (p<.01). CONCLUSION: Clinical measurement of the internal and external rotation of the hip using a universal plastic goniometer is effective to assess the hip condition. However, application of universal plastic goniometer requires careful attention in more accurate evaluation and research verification of the internal and external rotation of hip joint.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.1
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• pp.69-77
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• 2010

The failure rate model of External Environment Maintenance(EEM) for a system under severe environment is investigated. EEM, which is recently introduced concept, is a maintenance activity controlling external environment factors that potentially cause system failure such as cleaning equipment, controlling temperature (humidity) and removing dust inside of electronic appliances. EEM can not have any influence on the inherent failure rate of a system but reduce the severity of the external environment causing failure since it deals with only external environment factors. Therefore, we propose two failure rate models to express the improvement effect of EEM: The intensity reduction model and age reduction model. The intensity and age reduction models of EEM are developed assuming the quality of improvement effect is proportioned to an extra intensity or age respectively. The validation of proposed failure rate models is performed in order of data generation, parameter estimation and test for goodness-of-fit.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.190-190
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• 1999

CHF (Critical heat flux) on the external surface of the reactor vessel lower head is major key in the evaluation on the feasibility of IVR-EVC (In-Vessel Retention through External Vessel Cooling) concept. To identify the CHF on the external surface, considerable works have been performed. Through the review on the previous works related to the CHF on the external surface, liquid subcooling, induced flow along the external surface, ICI (In-Core Instrument) nozzle and minimum gap are identified as major parameters. According to the present analysis, the effects of the ICI nozzle and minimum gap on CHF are pronounced at the upstream of test vessel: on the other hand, the induced flow considerably affects the CHF at downstream of test vessel. In addition, the subcooling effect is shown at all of test vessel, and decreases with the increase in the elevation of test vessel. In the real application of the IVR-EVC concept, vertical position is known as a limiting position, at which thermal margin is the minimum. So, it is very important to precisely predict the CHF at vertical position in a viewpoint of gaining more thermal margins. However, the effects of the liquid subcooling and induced flow do not seem to be adequately included in the CHF correlations suggested by previous works, especially at the downstream positions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.4
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• pp.589-595
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• 2014

The error of instrument transformers is measured by connecting the external burden with the secondary terminal of the instrument transformers. Because the error of transformer is affected by the apparent power and power factor of the external burden, an accurate measurement of burden is important for transformer evaluation. We have developed the burden evaluation equipment for both potential transformer and current transformer by employing the series resistor in the range of $20m{\Omega}{\sim}5{\Omega}$ and the parallel resistor in the range of $1M{\Omega}{\sim}500{\Omega}$, respectively, together with visual basic program. We could reduce testing time more than 5 times by employing method developed in this study, compared with that developed in past. This method shows more better reliability by analyzing the evaluation results and fitting graphs of burden measurements. The test results of the developed system is compared with those obtained in the power meter analyzer to verify the validity.

• KIEAE Journal
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• v.16 no.3
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• pp.103-112
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• 2016

Recently, many New Han-oks have been constructing in all over the country to popularize as a type of green house. But, achievement of thermal performance of external wall is still the very important issue to become popular. Purpose: The purpose of this study is to verify the thermal performance level of modern New Han-ok through Temperature Difference Ratio inside(TDRi) analysis at corners of the external wall in Han-ok. Method: To achieve this goal, measurements were carried out in 12 Han-oks(experimental mock-up(1), exhibition Han-ok(1), happy village Han-oks(10)) by taking a infra-red thermography using thermal video system. Following are analysis items about connection joint between wall and wood columns of external wall conditions; the part between external wall and external wall(2D), external wall and ceiling(or floor)(2D), 2 external walls and ceiling(or floor)(3D) and so on. Result: It was analyzed that the probability of condensation at most of connection joint appear high and TDRi of 3D corners is higher than that of 2D corners in general. It means that the development of construction techniques about connection joint between wood columns and external wall is still required. The results of this study may be used to improve the construction technology of new Han-ok and as a basis for the specifying the desired thermal comfort environment of dwelling.

• Culinary science and hospitality research
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• v.9 no.4
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• pp.152-162
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• 2003

The study is aimed to find out the factors which have influence on customers' satisfaction from information and prompt them to repurchase, based on the patterns of information seeking which vary according to categories of traditional eating out processed food. 500 housewives living in megalopolis whose age ranges from 20s to 50s are targeted to the research, and the self-report questionnaires were used. and also the analysis on the frequency, t-test, and multiple regression were taken. The summarized conclusion is as following: First, in terms of the patterns of information seeking, consumers, in general, are found more likely to be internal seekers, who seek information based upon their past experience, rather than to be external seekers. Second, the comparison of satisfaction after purchase of the groups categorized by the patterns of information seeking shows that, in terms of traditional eating out processed food, on the contrary to other products, the satisfaction of internal seekers is higher than that of external seekers. Third, in both groups of internal seekers and external seekers, purchase assessment and the evaluation of efforts for information seeking are found to have influence on the intention to repurchase in terms of information seeking, but the influence of used information evaluation is partial.

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.209-218
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• 2008

The growth in services has focused issues of service quality both for commercial enterprises and across a range of public services and government institutions. The education sector, in particular, has undergone radical change to meet the needs of its varied constituents. This paper examines key issues in internal service, customer satisfaction, service quality, relational commitment as they apply in one particular education sector. The purpose of this study is to analyze effect of internal service on customer satisfaction, educational service quality. First, In the dimension of internal service, many factors affect internal customer's evaluation for overall satisfaction. They are categorized as five factors; tangibles, reliability, responsiveness, assurance, empathy. The results of this study supported the proposed conceptual framework overall. Therefore, we identified that internal service quality is the antecedent of an internal customer satisfaction, and the consequent variables of an internal customer satisfaction are educational service quality, external customer satisfaction. The major findings of this study are summarized as follows. First, some factors(tangibles, reliability, responsiveness, assurance, empathy) affected positively internal customer satisfaction. Second, external service quality affected positively educational service quality, external satisfaction. In other words, the more internal customers have experienced internal service, the higher internal service quality deliver educational service quality.

• IE interfaces
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• v.22 no.4
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• pp.336-346
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• 2009

One of primary assumptions on DEA is that all DMUs for evaluation should be homogeneous. In comparative analysis among DMUs with relative efficiency measurement, it should be evaluated under identical conditions by ruling out external environmental influences. In this study, a measurement of innovation efficiency using the three-stage approach is performed. The approach employs DEA to measure relative efficiency and Tobit regressions to control external variables affecting innovation activity. The approach applied to firms in Korean Innovation Survey: Service Sector 2003 and 2006. Final efficiency scores of the approach represent net efficiency of the innovation. This study found that there is a increasing on technical efficiency of third stage, and it has difference with first stage significantly. Besides, a decrease on standard deviation of third stage is found. It means DMUs biased lower due to unfavorable condition and ones biased higher due to favorable condition are fallen into an identical operating environment through the approach. A measurement of net efficiency, excluding external effects, ensures the homogeneity of DMUs so that improves the reliability in terms of its analysis results. This study is expected to provide a direction and to be a valuable reference to further evaluation of innovation performance in Korean service sector.

• Journal of the Ergonomics Society of Korea
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• v.24 no.3
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• pp.11-27
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• 2005

The objectives of this study are to analyze representative wrist postures while using hand tools and parts at general assembly processes, to evaluate perceived discomfort on the wrist when external loads are present, and to suggest an evaluation and prediction model of perceived discomfort. Sixteen subjects participated in an experiment to appraise perceived discomfort. Three types of the wrist postures with five levels of non-neutralities were analyzed when five levels of external load were applied to each posture. The ANOVA results showed that the perceived discomfort of wrist postures was significantly affected by both the wrist posture and external load (p$<$0.001). It was also shown that some of the interactions between external loads and the wrist postures(Flexion/$Extension^*$Load, Flexion/$Extension^*$supination/pronation, ulnar/radial $deviation^*$supination/pronation) were significant(p$<$0.001). The result implies that a new posture classification scheme for workload assessment methods may be needed to reflect such effects of external load and wrist posture. A regression model of perceived discomfort was developed with respect to wrist posture and external load from the experimental data. A subsequent experiment revealed that the correlation coefficient between the predicted values of perceived discomfort from the model and the actual values obtained from the experiment was about 0.98. It is expected that the results help to properly estimate the body stress resulting from worker's postures and external loads and can be used as a valuable design guideline to analyze potential hazard of musculoskeletal diseases in industry.