• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1057-1062
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• 2000

The purpose of this study is to practice the method which can estimate 28-days strength of concrete in advance. This method is made for reliant quality control. Based on existing experiment, concrete that flyash added and normal concrete are placed into wall structure, and it is examined the difference between experiment use concrete and field use concrete. The result of this study are as follows : 1) Core test specimen have 10% lower strength to standard curing specimen. 2) At 28-days accelerated strength by microwave, average 35% in normal concrete, average 23% in flyash added concrete. 3) At coefficient of determination between compressive strength and accelerated strength, 0.84 in normal concrete core, 0.86 in standard curing normal concrete, 0.86 in flyash added concrete, 0.90 in standard curing flyash added concrete.

• 대한가정학회지
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• 제40권7호
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• pp.83-100
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• 2002

The purpose of this study is to examine related variables to goods purchase by consumers using the home shopping of cable TV. For the purpose accomplishment, this study analyzed the variables which influence on the purchase by demographic variables, consumers'shopping propensity, perceived risk and benefit. The major findings are as follows; In the purchase of convenience goods, the variables which influence positively are sex, job(housewife), instantly impulse purchasing propensity, and diversity of goods information. On the other hand, the variables which influence negatively are risk of delivery & returned goods, and risk of quality. In the purchase of shopping goods, the variables which influence positively are state of marriage, job(nonspecialist), and diversity of goods information. On the other hand, the variables which influence negatively are pleasure of shopping-oriented, risk of delivery & returned goods, and risk of quality. In the purchase of specialty goods, the variables which influence positively are sex, income, convenience of time, and convenience of approach. On the other hand, the variables which influence negatively are pleasure of shopping-oriented, and risk of price & information restriction.

• 한국정보시스템학회지:정보시스템연구
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• 제8권1호
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• pp.93-108
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• 1999

The switching system is designed and developed to satisfy the performance design objectives recommended by ITU for call processing capacity and quality of service(QOS), etc. When the results by actual measurement at the system testing phase do not satisfy the performance design objectives, however, an effort is required to improve the performance. This paper presents a method for improving QOS by modifying the application programs for the switching system. In the proposed method, the sequence chart related to a delay time for call connection is modelled using PERT(Program Evaluation and Review Technique) network. Then, the criticality index of a message is calculated using Monte Carlo simulation to evaluate which message's processing time to decrease in order to decrease the delay time and thus to improve QOS. The criticality index of a block is also calculated to identify those software blocks that significantly contribute to the delay time.

• 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.

• 해양환경안전학회지
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• 제2권1호
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• pp.89-95
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• 1996

This paper describes a fuzzy controlled pre-chlorination technique for purifying the pulluted raw water in water purification lants. For the purpose of obtaining the high quality water, the appropriate pre-chlorine dosage rate has to be continuously adjusted according to a change in quality of a intake raw water, weather, solar nergy mount, temperature and etc. Therefore, the method of expressing an expert's empirical knowledge cumulated from his past carrier by fuzzy reasoning and the fuzzy controller design technique is necessary.In this paper fuzzy membership functions and rules accordingto emprircal knowledge and experimental field data were obtained, And also fuzzy cintriller design using four feedforward components for the determination of pre-chlorine dosage rate and four feedback ones for the compensation of its dosage rate with residual chlorine and its change rate, was executed.

• 대한산업공학회지
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• 제29권3호
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• pp.239-246
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• 2003

Individual items are produced continuously from an industrial process. Each item is checked to determine whether it satisfies a lower screening limit for the quality characteristic which is the weight of an expensive ingredient. If it does, it is sold at a regular price; if it does not, it is reprocessed or sold at a reduced price. The process mean may be adjusted to a higher value in order to reduce the proportion of the nonconforming items. Using a higher process mean, however, may result in a higher production cost. In this paper, the optimal process mean and lower screening limit are determined in situations where the probability that an item functions well is given by a logistic function of the quality characteristic. Profit models are constructed which involve four price/cost components; selling prices, cost from an accepted nonconforming item, and reprocessing and inspection costs. Methods of finding the optimal process mean and lower screening limit are presented and numerical examples are given.

• 대한산업공학회지
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• 제21권2호
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• pp.255-265
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• 1995

Due to advances in automated manufacturing systems and automatic inspection equipment, complete inspection has drown increased attention recently and has become a widespread practice. In a complete inspection plan all of the items are subject to acceptance inspection If an item fails to meet the predetermined specifications, it is rejected. In this paper, economic complete inspection plans are developed in situations where rejected items are reworked Complete inspections based on the performance variable of interest or a variable which is correlated with the performance variable are considered. Cost models are constructed which involve cost incurred by imperfect quality rework cast and quality inspection cost Methods of finding the optimal complete inspection plans are presented and numerical examples are given.

• 한국군사과학기술학회지
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• 제20권6호
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• pp.835-843
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• 2017

The Technology Readiness Assessment(TRA) has the advantage of identifying immature technologies in promoting weapon system research and development project. However, a more diverse set of information is required for the determination of phase shift and technical risk management for weapons system R&D projects. In this paper, we investigate the various indexes the various indexes proposed to overcome the limitations of the Technology Readiness Level(TRL) and analyze the possibility of applying to the actual weapons system R&D projects. Based on the analysis, it was possible to provide additional information that could not be presented in TRA using technical risk indexes other than TRL, confirming that it could be used for technical risk management for weapons system R&D projects.

• 품질경영학회지
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• 제39권2호
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• pp.329-336
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• 2011

The purpose of Phase I clinical trial is to identify the maximum tolerated dose with specific toxicity rate. The standard TER design does not guarantee the pre-specified toxicity rate. It depends on the dose-toxicity curves. Therefore it is necessary to check the expected toxicity rate of various dose-toxicity curves before we conduct clinical trials. We developed TERAplusB library to help this situation, especially in cancer research. This package will help design the cancer clinical trial. We can compare the expected toxicity rates, the expected number of patients, and the expected times calculated with various dose-toxicity curves. This process will help find the best clinical trial design of the proposed drug.

• 한국통신학회논문지
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• 제25권3B호
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• pp.510-518
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• 2000

A new video interpolation technique based on variable skip rate of video sequence is proposed in this paper. in the proposed technique. the determination whether a frame is skipped or not is done by the degree of motion complexity of the frame. If the motion complexity of a frame is low the frame is skipped. otherwise it is coded and transmitted. To determine the motion complexity of a frame a new technique using MEF (moving edge in frame),the set of pixels considered as moving edges in a frame. is introduced. In the course of decoding and interpolating of receiver., the motion field is segmented. For the purpose of dividing vector field morphological filtering is applied. Morphological filtering also used to smooth the boundaries between the changed and unchanged region. In the simulation results, the proposed technique shows higher quality and lower fluctuation of picture quality than the conventional techniques on conditioning of the same bit rate.