• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.54-59
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• 2023

In this paper, we analyze experimental results by applying the PHILS model to a lab-scale superconducting current limiter system for its actual application in medium-voltage direct current (MVDC) systems. Superconducting current limiters exhibit effective current-limiting performance in circuit breaker operations, particularly in limiting large fault currents within a short period, addressing the challenges posed by the increasing use of renewable energy and the integration of DC medium-voltage distribution systems. The development of such superconducting current limiters faces various technical and cost disadvantages, especially when applying a medium-voltage 35kV level system, which is intended for future introduction. The proven lab-scale superconducting current limiter system and the PHILS model are combined and integrated into the actual system. Our plan involves analyzing the limiter's performance, assessing its impact on the system, and preparing for its application in future medium-voltage systems. Utilizing RTDS, a simulation was conducted by connecting actual scaled-down equipment and systems, with the analysis results presented.

• Journal of Information Technology Applications and Management
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• v.29 no.6
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• pp.81-93
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• 2022

As deep learning technology in natural language and visual processing has rapidly developed, collaborative filtering-based recommendation systems using deep learning technology are being actively introduced in the recommendation field. In this study, OCF-GAN, a hybrid collaborative filtering model using GAN, was proposed to solve the one-class and cold-start problems, and its usefulness was verified through performance evaluation. OCF-GAN based on conditional GAN consists of a generator that generates a pattern similar to the actual user preference pattern and a discriminator that tries to distinguish the actual preference pattern from the generated preference pattern. When the training is completed, user preference vectors are generated based on the actual distribution of preferred items. In addition, the cold-start problem was solved by using a hybrid collaborative filtering recommendation method that additionally utilizes user and item profiles. As a result of the performance evaluation, it was found that the performance of the OCF-GAN with additional information was superior in all indicators of the Top 5 and Top 20 recommendations compared to the existing GAN-based recommender. This phenomenon was more clearly revealed in experiments with cold-start users and items.

• Journal of Science Education
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• v.37 no.2
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• pp.348-358
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• 2013

The purpose of this study is to develop the science item on computer-based performance assessment which is able to replace the assessment with actual experimental apparatus. The survey on the necessities and the difficulties of the assessment with actual experimental apparatus was conducted with 57 physics teachers. By reflecting the results of the survey, the computer-based assessment items which are related with constructing circuits with an ammeter and a voltmeter were developed. The developed computer-based assessment items were organized in similarity to assessment conducted with actual experimental apparatus, proper feedback was provided by students' performance in the process of assessment so as to grading performance results automatically. To achieve them, the algorithm was developed so that computer can judge the accuracy of students' performance results.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.5
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• pp.341-349
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• 2016

Currently, researches are being actively conducted in assessing seismic performance of nuclear facilities in USA and Europe. In particular, applying this technique of assessing seismic performance to design of isolation systems in nuclear power plants is being performed and then ASCE 4 Draft (2013) is being revised accordingly in the United States. In order to satisfy the probabilistic performance objectives described by seismic responses with certain confidence levels (ASCE 43, 2005), the probability distributions of these responses have to be defined. What is the minimum number of input ground-motions to obtain the probability distribution precise enough to represent the unknown actual distribution? Theoretical basis, for how to determine the minimum number of input ground-motions for given a logarithmic standard deviation to approximate the unknown actual median of the log-normal distribution within a range of error at a certain level of confidence, is introduced by Huang et al. (2008). However, the relationship between the level of confidence and the range of error is not stated in the previous study. In this paper, based on careful reviews on the previous work, the relationship between the level of confidence and the range of error is logically and explicitly stated. Furthermore, this relationship is also applied to derive the minimum number of input ground-motions in order to approximate the unknown actual logarithmic standard deviation. Several recommendations are made for determining the minimum number of input ground-motions in probabilistic assessment on seismic performance of facilities in nuclear power plants.

• Journal of Information Technology Services
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• v.16 no.1
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• pp.55-72
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• 2017

Many of the studies of visual attention that are currently underway are seeking ways to make application systems that can be used in practice, and obtained good results using not only simulated images but also real-world images. However, despite that previous studies of selective visual attention are models intended to implement the human vision, few experiments verified the models with actual humans and there is no standardized data nor standardized experimental method for actual images. Therefore, in this paper, we propose a new performance evaluation techniques necessary for evaluation of visual attention systems. We developed an evaluation method for evaluating the performance of the visual attention system through comparison with the results of the human experiments on visual attention. Human experiments on visual attention is an experiments where human beings are instinctively aware of the unconscious when images are given to humans. So it can be useful for evaluating performance of the bottom-up attention system. Also we propose a new selective attention system that guides the user to effectively detect ROI regions by using spatial and temporal features adaptively selected according to the input image. We evaluated the performance of proposed visual attention system through the developed performance evaluation method, and we could confirm that the results of the visual attention system are similar to those of the human visual attention.

• Journal of Korean Dental Hygiene Science
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• v.5 no.2
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• pp.165-174
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• 2022

Background: This study was conducted to investigate the actual status of dental hygienists' CPR-related educational experiences and the actual status of dental hygienists' CPR license retention, and to investigate the differences and correlations among CPR-related knowledge, attitudes, and performance abilities. Methods: An online self-reported questionnaire was filled out by 200 dental hygienists nationwide from May 6 to 29, 2019. The data regarding the sociodemographic characteristics, CPR-related knowledge, attitudes, and performance abilities were collected and analyzed using the chi-square test, independent t-test, one-way ANOVA, and the Pearson correlation coefficient using IBM SPSS Statistics version 20.0. Results: Dental hygienists with CPR-related education experience showed high levels of knowledge in the area. Dental hygienists with CPR-related education experiences and dental hygienists with CPR licenses showed high CPR performance abilities. Positive correlations are observed among CPR-related knowledge, attitude, and performance abilities. Conclusion: As CPR-related education has been found to be of value and importance to dental hygienists, systematic educational programs as well as support for regular education will need to be implemented.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.168-174
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• 2004

A shift algorithm of an automatic transmission is decided by the compromise between the performance and the fuel economy of the vehicle. But because in the traditional shia algorithm, throttle opening and vehicle speed are used to decide the shift points, the actual load of the vehicle is not exactly considered. In this paper, to consider the actual load, that is, the road grade and the vehicle acceleration, the longitudinal accelerometer is used to decide the shift points. As the result, the performance and the fuel economy of the vehicle which adapts the new shift algorithm are shown better than the traditional one.

• Journal of Applied Reliability
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• v.6 no.3
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• pp.239-254
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• 2006

In this research, first, the effect of Six Sigma activities and business performance will be checked based on case studies involving companies adopting Six Sigma and, secondly, the Six Sigma training effectiveness, Customer Satisfaction and Financial Performance, etc, will be evaluated to find out how related to Six Sigma Implementation. Finally, Six Sigma's Implementation Categories will be analyzed. The method used in this research was to select the research model and research hypothesis based on theoretical studies and the interesting aspects of the recent Six Sigma, along with case studies and research based on actual proof. Case studies and research based on actual proof showed that among 11 companies analyzed, a total of 11 companies obtained good results, and KIs were found to be factors of their success.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.161-169
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• 2001

At the end of 1999, the TeraCluster Project in the KISTI Supercomputing Center was initiated to explore the possibility of PC clusters as a scientific computing platform to replace the Cray T3E system in KISTI by 2002. Since actual performance of a computing system varies significantly for different architectures, representative in-house codes from major application fields were executed to evaluate the actual performance of systems with different combination of CPU, network and network topology. As an example of practical CFD(Computational Fluid Dynamics) simulations, the flow past the Onera-M6 wing and the flow past a infinite wing were simulated on a clusters of Linux and several other hardware environments.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.301-310
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• 1994

The feasibility of using ultrasonic-wave doppler sensors for a measurement of the actual ground speed of agricultural machines was investigated. The actual ground speed is estimated from the doppler shift frequencies of the two ultrasonic-waves transmitted to and received from a moving object. A prototype of the speed-measurement system was designed and constructed for the performance test. The measurement system showed a good performance with a flat surface at speeds lower than 3m/s. However, it was failed to receive the reflected signals from the rough and irregular soil surfaces. Further researches to solve this problem and to improve its performance are now underway.