• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.56-63
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• 2015

The optimization is an important role in wide geographical distribution of electrical power market, finding the optimum solution for the operation and design of power systems has become a necessity with the increasing cost of raw materials, depleting energy resources and the ever growing demand for electrical energy. In this paper, the real coded biogeography based optimization is proposed to minimize the operating cost with optimal setting of equality and inequality constraints of thermal power system. The proposed technique aims to improve the real coded searing ability, unravel the prematurity of solution and enhance the population assortment of the biogeography based optimization algorithm by using adaptive Gaussian mutation. This algorithm is demonstrated on the standard IEEE-30 bus system and the comparative results are made with existing population based methods.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.669-672
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• 2001

Generally, previous converter is divided into two categories to get high power factor and good output regulation. These two categories can be combined a category with a main switch. These converter is called Single Stage PFC Converter. This approach has good electrical characteristics of high power factor and fast output voltage regulation. The cost and size are important factor to design the converter in low power system. Even single stage can reduce the size and cost, but this approach needs to have additional circuit like control, PWM circuit. To improve these demerits, Top switch is one of good choice In reduce and size in low power single stage converter. Because it has the ability of current limit, thermal protection, oscillator, control circuit as well as a main switch ability.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.167-176
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• 2008

Vulnerability assessment of power systems is important so as to determine their ability to continue to provide service in case of any unforeseen catastrophic contingency such as power system component failures, communication system failures, human operator error, and natural calamity. An approach towards the development of on-line power system vulnerability assessment is by means of using an artificial neural network(ANN), which is being used successfully in many areas of power systems because of its ability to handle the fusion of multiple sources of data and information. An important consideration when applying ANN in power system vulnerability assessment is the proper selection and dimension reduction of training features. This paper aims to investigate the effect of using various feature extraction methods on the performance of ANN as well as to evaluate and compare the efficiency of the proposed feature extraction method named as neural network weight extraction. For assessing vulnerability of power systems, a vulnerability index based on power system loss is used and considered as the ANN output. To illustrate the effectiveness of ANN considering various feature extraction methods for vulnerability assessment on a large sized power system, it is verified on the IEEE 300-bus test system.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.877-887
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• 2022

A new reactor concept is described that directly couples a supercritical CO₂ (sCO₂) power cycle with a CO₂-cooled, heavy water moderated pressure tube core. This configuration attains the simplification and economic potential of past direct-cycle sCO₂ concepts, while also providing safety and power density benefits by using the moderator as a heat sink for decay heat removal. A 200 MWe design is described that heavily leverages existing commercial nuclear technologies, including reactor and moderator systems from Canadian CANDU reactors and fuels and materials from UK Advanced Gas-cooled Reactors (AGRs). Descriptions are provided of the power cycle, nuclear island systems, reactor core, and safety systems, and the results of safety analyses are shown illustrating the ability of the design to withstand large-break loss of coolant accidents. The resulting design attains high efficiency while employing considerably fewer systems than current light water reactors and advanced reactor technologies, illustrating its economic promise. Prospects for the design are discussed, including the ability to demonstrate its technologies in a small (~20 MWe) initial system, and avenues for further improvement of the design using advanced technologies.

• 대한가정학회지
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• 제29권2호
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• pp.17-34
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• 1991

The purpose of this study was to find out problems which occured between clothes and motor ability traits of the hemiplegic aged. The samples were 32 hemiplegic aged men and were compared with 43 healthy aged men. Motor ability of the samples were measured by ROM test, muscle power test and finger function test(grip strength, hand's coordination, lateral pinch, 3pt. pinch). Design of the clothes consisted of 25 variables and the analysis of dressing and undressing motion consist of 10 motions of dressing and undressing dress shirts and 8 motions of trousers. The results were as follows: 1. There were significant relationship between ROM and muscle power and finger function of the hemiplegic aged(P<.001). 2. There were significant differences between the nomal side's finger function of the hemiplegic aged and that of the healthy group(P<.001). 3. The designs of clothes such as tutle neck line, long sleeve, button cuffs, fastening lace, open zipper and belt of trousers gave much difficulty to the hemiplegic when dressing and undressing. 4. The most difficult motion of dressing and undressing was fastening when dressing both dress shirts and trousers. 5. There were partly significant relationship between design of clothes and ROM, muscle power, finger function of hemiplegic aged man. 6. There were partly significant relationship between the degree of difficulty in dressing and undressing motions and ROM, muscle power, finger function of hemiplegic aged man.

• 대한물리의학회지
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• 제16권1호
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• pp.33-39
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• 2021

PURPOSE: This study compared the body composition according to the sport of short-distance and middle & long-distance athletes to identify the factors that affect the body composition. METHODS: Forty-eight athletes selected as youth national athletes in 2019 participated in the study. The study participants measured the length of the lower extremities, body composition, and anaerobic ability. An independent sample t-test was conducted to compare the body composition according to the event. In addition, the Pearson correlation was performed to identify the factors that influence the body composition. RESULTS: The leg length of the Short and Middle & long-distance athletes were similar (p = .584). On the other hand, there were differences in the body fat percentage (p = .001), lean percentage (p = .001), and BMI (p = .001). In addition, the body fat percentage was correlated with the lean body mass (r = .419) and BMI (r = .447). Furthermore, the lean body mass was correlated with the BMI (r = .849) and the peak power (r = .662) and mean power (r = .686) of the anaerobic capacity. Moreover, the BMI was correlated with the peak power (r = .490) and mean power (r = .543) of the anaerobic capacity. The peak power of the anaerobic ability was correlated with the mean power (r = .931). CONCLUSION: The body composition differed according to the sport. The body fat percentage correlated with the lean body mass and the BMI. The lean body mass correlated with the BMI, peak power of anaerobic ability, and mean power. The BMI correlated with the anaerobic capacity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.589-590
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• 2013

The fast development of electronic devices towards wireless, portable and multi-functionality desperately needs the self-powered and low maintenance power sources. The possibility to coupling the nanogenerator to wearable and portable electronic device facilitates the self powered device with independent and self sustained power source. Nanogenerator has ability to convert the low frequency mechanical vibration to electrical energy which is utilized to drive the electronic device [1]. The self powered power source has the ability to generate the power from environment and human activity has attracted much interest because of place and time independent. The human body motion based energy harvesting has created huge impact for future self powered electronics device applications. The power generated from the human body motion is enough to operate the future electronic devices. The energy harvesting from human body motion based on triboelectric effect has simple, cost-effective method [2, 3] and meet the required power density of devices. However, its output is still insufficient to driving electronic devices in continues manner so new technology and new device architecture required to meet required power. In the present work, we have fabricated the triboelectric nanogenerator using PDMS polymer. We have studied detail about the power output of the device with respect to different polymer thickness and varied separation distance.

• KIEE International Transactions on Power Engineering
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• 제2A권3호
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• pp.89-94
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• 2002

In this paper, a protection system using a Multi-Agent concept for power distribution networks is proposed. Every digital over current relay(OCR) is developed as an agent by adding its own intelligence, self-tuning and communication ability. The main advantage of the Multi-Agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent. In order to cope with frequent changes in the network operation condition and faults, an OCR agent, suggested in this paper, is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents. Through this kind of coordination and information exchanges, not only a local but also a global protective scheme is completed. Simulations in a simple distribution network show the effectiveness of the suggested protection system.

• 한국융합학회논문지
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• 제10권7호
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• pp.87-92
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• 2019

본 연구의 목적은 자아존중감과 공감능력, 대인관계능력과의 융합 관계를 파악하고자 전북지역 치위생과 351명을 대상으로 조사하였다. 수집된 자료는 SPSS software program 22.0 통계프로그램으로 분석하였다. 대인관계능력은 건강상태(p=0.005)와 전공만족도(p=0.004)에서 통계적으로 유의한 차이가 있었다. 자아존중감과 공감능력, 대인관계능력은 양의 상관관계를 보였다(r=0.600, p<0.01). 대인관계능력에 영향을 주는 융합 요인은 자아존중감과 공감능력이었으며(p<0.001) 설명력은 38.0%였다. 따라서 자아존중감과 공감능력, 대인관계능력을 향상시키기 위한 치위생 교육프로그램 개발이 필요하리라 생각된다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.880-883
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• 2015

배전선 케이블을 식별하는데 전력선 통신기술이 제안된다. 전력선 통신 기술의 응용 영역을 확대하게 된다. 고주파 신호는 배전선에서 전달 능력에 한계 능력을 갖는다. 보통 배전계통의 전력 변압기는 그러한 고주파 신호의 전달을 차폐하게 된다. 이러한 제안된 전송제한 방법을 사용하여 케이블을 식별하는데 적용된다. 새로운 형태의 전력선 케이블 식별시스템이 설계 및 구현된다. 시스템은 전력선 통신 모듈을 바탕으로 송수신기로 구성된다. 이론적 개념을 검증하기 위한 실험이 행하여진다. 또한 시뮬링크 시뮬레이터를 사용하여 개념에 대한 이해를 위한 시뮬레이션이 수행된다.