• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.211-215
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• 2017

The APF (All Pass Filter) method that utilizes the computational power of the controller is most commonly used. However, since the calculation of the filter coefficient is complicated, the calculation is carried out in advance. It is difficult to apply it to the frequency fluctuation environment because the coefficient value is fixed. In this paper, a new control method of single phase PLL that can be usefully used in PWM converter device for electric railway was explained. Comparison and examination of similarities and differences between the conventional APF method PLL controller method and the newly proposed modified MA filter method PLL technique were performed. The possibility of implementation of the modified MA filter method through computer simulation was analyzed. In conclusion, the method proposed as the conclusion was applied to the APU(Auxiliary Power System) of 8200 Series Electric Locomotive and its usefulness was confirmed.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.1
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• pp.57-62
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• 2019

In this paper, oneM2M based data monitoring and acquisition system is designed and implemented to measure and transmit the voltage, current, temperature, acceleration and vibration of the motor. The proposed system can detect electrical faults (overcurrent, reverse phase, phase loss, ground fault) and mechanical faults (MC counter, motor operation time, bearing and winding temperature, motor speed, insulation resistance). The system consists of sensor data collection, web server, php, database, wired/wireless communication system. The insulation resistance and the motor speed were measured, and the experimental results were similar for both the test resistance value and the reference input value.

• Journal of Power Electronics
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• v.13 no.6
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• pp.955-963
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• 2013

To acquire a performed and practical solution that is free from chattering, this study proposes the use of an adaptive super-twisting algorithm to drive a single-phase induction motor. Partial feedback linearization is applied before using a super-twisting algorithm to control the speed and stator currents. The load torque is considered an unknown but bounded disturbance. Therefore, a time-varying switching gain that does not require prior knowledge of the disturbance boundary is proposed. A simple sliding surface is formulated as the difference between the real and desired trajectories obtained from the indirect rotor flux oriented control strategy. To illustrate the effectiveness of the proposed control structure, an experimental setup around a digital signal processor (dS1104) is developed and several tests are performed.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2237-2250
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• 2021

The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time. On the other hand, the primary concern with the extended use of analog systems is the aging effect, such as mechanical failures, environmental degradation, and obsolescence. The transition to a digital-based Man-Machine Interface Systems (MMIS) in Korea and other countries has been accelerating, but some systems are still analog-based IC systems, such as the ENFMS in APR1400 NPPs. Digitalized ENFMS can become a reality using computers and microprocessors owing to the progress in digital electronics and information technology. This paper presents the result of the first phase of the research on the digitalization of the ENFMS signal processing electronics for NPPs operated or produced in Korea. It has two main parts: (1) review engineering bases of ex-core neutron flux monitoring system, including nuclear engineering, instrumentation techniques, and analog and digital signal processing techniques, and (2) analysis of analog signal processing electronics of ENFMS for OPR1000 and APR1400 power plants. They are prerequisite to the second phase of the research which is the detailed implementation of the digitalization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.391-394
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• 2014

In this paper, we introduce a method of determining the absolute position of the rotor for the vector control of Hall sensor type multi-pole BLDC motor using the DSP(TMS320F28335), and implement an algorithm to complement the problems of the conventional method. The switching method of the inverter for providing desired sinusoidal current to each phase of a motor, we adopt Space-Vector pulse width modulation method. In order to increase the speed range, Field-Weakness control method are used. In order to verify the proposed algorithm, we compare the value of Iqe, Ide and phase currents with the values before compensated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.35-46
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• 2006

The current Internet Key Exchange protocol(IKE) which has been used for key exchange of security system was pointed out the faults of scalability, speed, efficiency and stability. In this research, we tried to resolve those faults, and implemented the newly designed IKEv2 protocol in the IPsec test bed system. In the trend of network expansion, the current Internet Key Exchange protocol has a limitation of network scalability, so we implemented the new Internet Key Exchange protocol as a recommendation of RFC proposal, so as to resolve the fault of the key exchange complexity and the speed of authentication process. We improved the key exchange speed as a result of simplification of complex key exchange phase, and increased efficiency with using the preexistence state value in negotiation phase.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.206-211
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• 2021

Internet users are increasingly invited to express their opinions on various subjects in social networks, e-commerce sites, news sites, forums, etc. Much of this information, which describes feelings, becomes the subject of study in several areas of research such as: "Sensing opinions and analyzing feelings". It is the process of identifying the polarity of the feelings held in the opinions found in the interactions of Internet users on the web and classifying them as positive, negative, or neutral. In this article, we suggest the implementation of a sentiment analysis tool that has the role of detecting the polarity of opinions from people about COVID-19 extracted from social media (tweeter) in the Arabic language and to know the impact of the pre-processing phase on the opinions classification. The results show gaps in this area of research, first of all, the lack of resources when collecting data. Second, Arabic language is more complexes in pre-processing step, especially the dialects in the pre-treatment phase. But ultimately the results obtained are promising.

• Child Health Nursing Research
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• v.28 no.2
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• pp.112-123
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• 2022

Purpose: This study aimed to develop and evaluate a mobile application focusing on developmental support care for infants born prematurely. Methods: An application was developed using the analysis, design, development, implementation, and evaluation model. In the analysis phase, previous research was evaluated through big data text-mining and a literature review. In the design phase, the preliminary content of the application was designed, and the content validity and comprehension were verified. A hybrid application was developed and used by eight experts and ten users, who evaluated the layout of the mobile application and their satisfaction with it. Results: The content of the designed application comprised a diary, customized information, developmental play, and community. The mean scores for layout were 3.73±0.47 and 3.43±0.68 out of 4 points among the experts and users, respectively. Users' mean satisfaction score was 3.70±0.70 out of 5 points. Conclusion: The information provided by the mobile application was evaluated as consistent and systematic. The application was also found to be satisfactory by infants' parents. The mobile application developed through this study is expected to be effective in supporting the development of children born prematurely.

• Child Health Nursing Research
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• v.29 no.2
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• pp.137-148
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• 2023

Purpose: We developed a virtual reality (VR) program for use in pediatric nursing practicums to help nursing students learn to measure vital signs in children. Methods: The analysis, design, development, implementation, and evaluation model was employed between July 2021 and December 2021 at a university in South Korea. In the analysis phase, in-depth interviews were conducted with four nursing students, two nursing school graduates, and four experts. The topic and contents of the VR program were settled in the design phase. The VR program was developed and subsequently used and evaluated by 20 nursing students and four experts. Results: The contents of the VR program for pediatric nursing practicums included the measurement of vital signs in a newborn baby and a young child, as well as an evaluation system. The mean score for the nursing students' satisfaction with practice was 4.02 out of 5 points. The mean scores for overall satisfaction with the VR program were 4.15 and 4.79 out of 5 points for nursing students and experts, respectively. Conclusion: The VR program developed in this study allows nursing students to practice measuring vital signs in children, thus improving the students' clinical performance in pediatric nursing.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.160-168
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• 2007

Conflicts of interest and independent agenda of the parties brought together for implementation of a construction project often leads to dispute in Contract and claim situations. Construction Industry is notorious for claim that is managed on its arising and there lacks an endeavor to minimize the breeding grounds through efficient planning and alignment to purpose, of all contract-documents. There failure of a concerted effort entails wastage of resources, delayed completion of facilities and stained relationships of parties when collide in mistrust in contract to win over the other. There needs a focus on the claim breeding issue and establish an effective mechanism to deal with disputes in urgency. Claim occurs mostly during the construction phase. But the seeds of claim and nutrients essential for development are contained in the contract documentation and the information supplied or not in pre-contract phase. Opportunity to prevent nutrients for seed of Claim comes to an end once tender-documents are finalized, the contract is awarded and established or not a mechanism for dealing with claim situation. The processes presented here would help in minimizing the breeding grounds and emergence of disputes during progression of works and dealing with eventualities in forceful manners for finding a resolution most effectively in relevant time.