• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.211-214
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• 2002

We present gray scale implementation method based on QMA driving technique. We clarified the mechanism of wall charge quantization through discharge current measurement. We used three wall charge states to implement gray scale. The cells would be one of fully-ON, half-On, and OFF states. We built a five sub-fields 243 level gray scale with sustain pulse count of 2, 6, 18, 54, and 162.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.937-940
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• 1992

A cost-saving feeding rate contro method for a batch reaction process is proposed by reconfigurating the flow rate control loop where the feeding rate is estimated by differentiating weight measurement. While the existing control methods require either a flow rate measurement device or a flow rate estimator, the proposed method is devised not to require neither of these facilities by directly controlling the tank weight with a time-varying set point. Experimental evaluation in a pilot-scale unit shows that the proposed method can significantly reduce the actuator hunting of the existing method where the flow rate is estimated by differentiating the weight measurement.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.1
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• pp.1-9
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• 1988

This paper descibes a method for the state estimation in power systems with interconnected AC/DC system. The state values in interconnected AC/DC system are estimated using measurement values with the pseudo measurement so that the number of telemetering measurement can be reduced. Especially, the state values in AC system are estimated through hierarchical method after system decomposition including superposition bus was formed for the state estimation in large-scale power systems. The results of the application to the two model power systems show the dffectiveness of the presented algorithms.

• Journal of Digital Convergence
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• v.16 no.2
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• pp.421-430
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• 2018

The purpose of this study is to analyze the scale of health risk behaviors among adolescents in Daegu area. The purpose of this study was to develop a health risk behavior measurement item for the adolescent adolescents in Korea and to analyze the validity (CVR) of the existing THI measurement items and then to quantify the health risk behavior Were compared and analyzed. As a result of the analysis, the reliability of the health risk behavior scale of adolescents developed through the factor analysis was verified to derive measurement items such as general condition, respiratory, circulatory, digestive, mental health and other items. The reliability and validity of the developed health risk behavior scale were found to be fairly good. Through these studies, it will be possible to develop a preventive program that can reduce the risk of health related adolescents' youth, and to devise a strategy that can provide basic data for policy formulation.

• Journal of Veterinary Clinics
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• v.39 no.3
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• pp.114-120
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• 2022

The purpose of this study is to examine the status of quality control using multipurpose phantom of ultrasound equipment used in hospital of veterinary college in South Korea by using ATS-539 multipurpose phantom so as to examine quantitative and objective new image evaluation method. Specialists discussed and analyzed multipurpose phantom images acquired by using convex transducer of 10 ultrasound imaging devices, currently used in 9 veterinary colleges, at 4.0-6.0 MHz. Total 8 items that can be measured with ATS-539 multipurpose phantom including dead zone, vertical and horizontal measurement, axial/lateral resolution, sensitivity, focal zone, functional resolution and gray scale/dynamic range were evaluated. For qualitative evaluation, valid decisions were made based on dead zone, axial/lateral resolution, and gray scale/dynamic range which are resolution index, and coefficient of variation (COV) and blind referenceless image spatial quality evaluator (BRISQUE) were found to increase objectivity. As a result of experiment, all the targeted ultrasonic devices were found appropriate from qualitative evaluation items of dead zone, axial/lateral resolution, and gray scale/dynamic range. In other evaluation items, they were found to be appropriate from focal zone and vertical measurement of quantitative evaluation while inappropriate from horizontal measurement, sensitivity, and functional resolution. COV value was 0.12 ± 0.04, and BRISQUE value was 47.77 ± 2.77, both analysis results show that the noise level of all ultrasonic devices was located within tolerance range. Upon image examination using ATS-539 multipurpose phantom, they were 100% appropriate with inspection standards of dead zone, axial/lateral resolution, and gray scale/dynamic range, and besides, focal zone and functional resolution can be used as evaluation items. In the field of veterinary medicine, 8 standard items using ATS-539 multipurpose phantom and image evaluation items using COV and BRISQUE can be used as standards for quality control of ultrasonography machine.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.1
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• pp.28-36
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• 2018

The experimental results of the model tests for the twin propeller cavitation noise are presented. The model test was carried out by means of procedure of noise measurement followed by the signal processing and full-scale extrapolation. In order to convert the measured sound pressure level into the sound source level, transfer function measurements for three conditions were performed according to the combination of locations and number of virtual sources. White noise and LFM signal were used as a source signals to examine the influence of the input signal. For the twin propellers, 5 transfer functions were defined and the results were discussed. Cavitation noise measurement tests were performed similarly to the transfer function measurement test. Noise source localization analysis was performed to confirm the test effectiveness. It was confirmed that the source level of the twin propeller can be estimated reliably by using transfer function corrections. Finally, the model test results were converted into full-scale by applying the ITTC '87 model-ship scaling raw, and the validity of the model test was confirmed by comparison with the full-scale measurement result.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.1-11
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• 2017

The purpose of the study is to develop an online measurement scale for diagnosing self-directed learning ability for students in Korea. In order to achieve the goal, literature review, case analyses, and experts interview were carried out and finalized the blended-learning based SMMIS model. A total of 1,626 elementary, middle and high school students participated in the scale survey to validate the credibility and validity. Based on these results, an online measurement tool for self-directed learning was developed. The tool can be used in blended-learning environment to maximize its effectiveness. In conclusion, we discussed about implications and strategies for the blended-learning based on self-directed learning program model for young students, and suggested future vision and further research.

• Proceedings of the Korean Society of Rheology Conference
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• 2001.09a
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• pp.157.2-157
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• 2001

• Korean Journal of Human Ecology
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• v.21 no.5
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• pp.819-835
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• 2012

The purpose of this study was to develop and test the validity of an assessment scale for determining the competency of early childhood teachers practicing unification education. For this purpose, an evaluation scale was constructed and then tested for reliability and validity. Participants for this study included 266 early childhood teachers in the unification education field. In order to the measure reliability and validity of this scale, Exploratory Factor Analysis and Confirmatory Factor Analysis were conducted with SPSS 18.0 and AMOS. The result of this study identified four principal factors: 1) Instruction skills, 2) Evaluation, 3) Attitude, and 4) Knowledge. The results of this study supported the scale's reliability and legitimacy as a valid instrument for the evaluation of early childhood teacher's competence in unification education.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.3
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• pp.292-299
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• 2013

The measurement in the manufacturing process of curved ship hull plates still depends on wooden templates as a standard instrument. The metrology-enabled automation in the shipbuilding process has been challenged instead of line measurement with wooden templates. The developed measurement system consists of a CCD camera, multiple structured laser sources and 3-DOF motion device. The system carries out measurement of curved profiles for large scale plates by an optical triangulation method. The results of experiment conducted in a manufacturing shop demonstrate the accurate and robust performance.