• Proceedings of the KIEE Conference
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• summer
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• pp.515-517
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• 2004

현재 배전선로는 4가지 접지종별을 준용하여 피뢰기, 가공지선, 변압기, 기기류, 중성선 둥을 접지시공하고 있다. 또한 규정된 접지저항값에 따라 접지전극을 시공하고 2년에 1회 주기적으로 접지저항값을 측정하고 관리하고 있다. 현재 접지저항값의 측정에는 휴대가 간편하고 측정이 용이한 HOOK-ON 접지저항계가 주로 이용되고 있다. 그러나 HOOK-ON 접지저항계는 $\pm$5[\%]$정도의 측정오차 뿐만 아니라 측정선 전류가 1[A]를 초과하는 경우 변류용 철심이 포화되어 측정이 어렵다는 단점을 가지고 있다. 따라서 본 논문에서는 HOOK-ON 측정기법의 단점을 보완하여 다중접지 배전계통에서 부하 불평형 및 고조파 둥에 의해 발생하는 접지선 누설전류를 전류원으로 이용하는 접지전극의 접지저항을 측정하는 새로운 측정기법을 제안하였다. 또한 이를 실제 배전계통에 적용하여 전위강하법을 이용하여 측정한 접지저항값과 비교하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.163-168
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• 2003

정보기술의 급속한 발전과 더불어 산업 전반에 걸쳐 기존의 경계가 흐려지는 통합(Convergence)시대가 도래하고 있다. 특히, 통신서비스산업은 유선 및 무선통신 서비스가 성숙기에 접어들면서 다른 산업에 비하여 통합의 속도가 두드러지게 빠르게 진행되고 있다. 이미 서비스$\cdot$단말$\cdot$인프라의 통합을 통해 시간과 장소 및 단말기의 종류에 관계없이 일관된 서비스를 제공받고자 하는 욕구가 급속히 증가하고 있다. 국내 각 사업자들은 기존시장을 방어하고 나아가 새로운 시장을 개척하기 위한 방안의 하나로 유무선 통합 서비스 제공에 나서고 있는 가운데, 정부규제 정책들을 둘러싼 이해관계자들간의 첨예한 대립이 계속되고 있어 유무선통합서비스의 제공에 대한 관심이 고조되고 있다. 본 고에서는 유무선통합서비스의 최근 동향을 살펴봄으로써 국내 유무선통합 서비스의 활성화를 위한 지표로 삼고자 한다.

• 한국IT서비스학회:학술대회논문집
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• 2003.05a
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• pp.117-123
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• 2003

인터넷 접속채널과 접속망이 다양해지고 채널활용이 다차원적으로 가능함에 따라 유무선의 다중 채널통합에 대한 관심이 고조되고 있다. 이는 유무선 인터넷 채널통합에 관한 방향이 필요하며, 유선과 무선인터넷의 채널통합 이슈에 대한 분석이 필요한 시점이라 할 수 있다. 본 연구에서는 유무선 인터넷 채널통합과 관련된 문제점 및 이슈를 분류하였으며, 유무선 채널통합을 크게 Interface 통합관점과Business Model 간의 통합관점으로 살펴보았다. 인터페이스 관점에서는 디스플레이, 입출력장치, 컨텐츠로 구분하여 채널통합 문제를 유형별로 분류하였다. 그리고 비즈니스 모델 관점에서는 무선인터넷 서비스 유형 및 특성을 분석하여 비즈니스의 채널통합 방향성을 제시하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.56-61
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• 2008

Because the harmonic disturbance characteristic which makes voltage drop and the deterioration of instantaneous power quality in electrical power system overheats the NGR and the customer capacitor and malfunctions the OCGR and AMR, it is necessary for electric power company to take active measures to reduce this disturbance. International Electrotechnical Commission(IEC) 61000-3-2 specifies limits for harmonic current emissions generated by low voltage(LV) electrical equipment whose input current $\leq$ 16(A) per phase. Analysis shows that limits for Class A equipment in IEC are calculated using the reference impedance of LV system and maximum permissible voltage and limits for other Classes are also calculated based on limits for Class A. Therefore we have calculated four(4) internal limits for LV electrical equipment using the korea reference impedance and maximum permissible voltage in this paper.

• Journal of IKEEE
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• v.25 no.4
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• pp.710-715
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• 2021

Power line signal can show disturbances due to various causes. Typical anomalies are temporary sag/swell of the amplitude, flat topped signal, and harmonic distortions. The disturbances need to be detected and treated properly for the quality of the power signal. In this study, the power disturbances are detected using the inflection points (IP). The inflection points are defined as points where local maxima/minima or the slope changes occur. The power line signal has a fixed IP pattern since it is basically sinusoidal, and it may have additional inflection points if there is any disturbance. The disturbance is detected by comparing the IP patterns between the normal signal and distorted signal. In addition, by defining a cost function, the time instant where the disturbance happens can be decided. The computer simulation shows that the proposed method is useful for the detection of various disturbances. The simple sag or swell signal only shows the amplitude changes at the detected inflection points. However, the flat top signal and harmonically distorted signal produce additional inflection points and large values in the cost function. These results can be exploited for the further processing of disturbance classification.

• Korean Journal of Oriental Medicine
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• v.2 no.1
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• pp.1-25
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• 1996

The purpose of this paper is to study the basic medicine of the Gojoseon(古朝鮮) dynasty, especially 5 fields which are the theory of yin-yang(陰陽論), the theory of 5 progressive phasis(五行論), the theory of mind-body(心身論), Seon-gyo(仙敎), acupuncture(鍼術). The theory of yin-yang can be studied in the point of contents of it, not the name of it. Whan-in(桓因) is the god of sky, Woong(熊) is the god of earth. Whan-woong(桓雄), who is the son of Whan-in(桓因), came down from the sky, turned into a man. Woong(熊) lived in the cave, eating garlic and wormwood for 21days, got out of it and turned into a woman. The changes occurred by the mutual aid of Whan-woong and Woong. The theory of 5 progressive phasis can be founded in the archery. The bow and arrow is made of cucumber, horn and ligament of cow, glue made from airbladders of sciaenoid fish, which belong to mock(木). Beejeongbeepal(非丁非八) and make strong one's abdomen(腹實) belong ti soo(水), empty out one's chest(胞虛) belongs to whar(畵), thrusting(前推泰山) belongs to mock(木), shooting(發如虎尾) belongs to geom(金). Basically mind and body have no differance. Mind without body does not exist. Exocism excites the exorcist to the condition of whar(火). There are 3 parts, as treaLment, prevent, regimen, in the medicine. 2 parts as idealism and realism are in regimen. Seon-gyo(仙敎) belongs to the idealism of regimen. In China, is became Taoism(仙敎) later The art of accupunture was developed in the Gulf of pohair(渤海灣).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.155-161
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• 2005

Nonlinear electronic loads used at office buildings distort the voltage and current waveform that cause the overheating of transformer losses, ELB(Electrical Leakage Breaker) tripping, and so on. This paper analyzed waveform distortion characteristics at several once buildings by comparing with magnitude of voltage and current harmonics, crest factor of voltage and current, phase voltage and current unbalance. As a consequence, severe current waveform distortion in phase and neutral line by harmonics and high current unbalance rates by unbalanced using of single loads among the three phases are investigated. The results of the study can be used in making decisions regarding reasonable and economical operating of loads at office buildings.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.11
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• pp.1034-1046
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• 2013

In this paper, a design of a GaN HEMT power amplifier using output matching circuit with arbitrary harmonic impedances is presented. The adopted GaN HEMT device, TGF2023-02 of TriQuint Semiconductor, was packaged in commercial package. The optimal impedances of the GaN HEMT package are extracted from load-pull simulation at package input and output reference planes. The targets of load-pull simulation are the highest output power at fundamental frequency and the highest efficiency at $2^{nd}$ and $3^{rd}$ harmonic frequencies. Because of fixture in the package, the extracted impedances shows arbitrary harmonic impedances. In order to match the optimal impedances, output matchin circuit which has 4 transmission lines is presented. Characteristic impedances and electrical lengths of the transmission lines are mathmatically calculated. The power amplfiier with $54.6{\times}40mm^2$ shows the output power of 8 W at the fundamental frequency of 2.5 GHz, the efficiency above 55 %, and harmonic suppression of above 35 dBc at the $2^{nd}$ and the $3^{rd}$ harmonics.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.2
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• pp.57-79
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• 2001

[Go-Choseon], the first volume of Samgukyusa, is composed of two parts, the part of myth and that of history. There are very similar divinities between Hwanwoong in the myth of Dangun and YanDi-ShenNong of China: the solar divinity essential for survival of mankind and agriculture, the agriculture divinity said to have taught fanning, the medicine divinity said to have taught the characteristics of herbs and how to prevent diseases, the cultural hero who delivered civilization, and son on. During the transition from the age of myth to the age of history, the roles of gods had changed from the creation of the world to civilization and rule. The roles of Hwanwoong and YanDi-ShenNong were civilization and it was related with their divinities. Hence, regardless of a little difference, the myth of Hwanwoong and that of YanDi-ShenNong were created at the same stage of spiritual and material civilizations of Korea and China. This paper looks at the essence of [Wiseo] and the age of Hwanwoong through historical records. In my opinion, [Wiseo] is not a chinese history' book. The record, "According to [Wiseo] there had been Dangun-Wanggum 2,000 years ago" indicates the time [Wiseo] was written. 'Wi' means Wlman-choseon. Going back about 2,000 years from Wiman-choseon, the historical dates of the establishment of [Go-Choseon] almost dovetails to the age of King 'lao. So, there is a possibility that [Wiseo] is a history book of Wiman-Choseon dynasty which was written to prove the legitimacy of the dynasty by showing it succeeded to the Dangilll-Choseon dynasty. The sentences, "governed the country for 1,500 years" and "conferred Gija the position of king of Choseon" are very important records showing the age of the establishment of Dangun-Choseon. Gija came to Choseon in B.C 1122 when Yin replaced Zhou in the Choinese Continent. From the fact that Dangun had governed Choseon, we could reason out that Go-Choseon was established in B.C. 2622 that is much eariler than the era of king Yao, and that corresponds 'With the era of HuangDi(B.C 2698-2358). Hence, the era of Hwanwoong, the father-god of Dangun, might be later than B.G 3000 which conforms to the era of YanDi-ShenNong(B.C 3218-2600). Therefore, this paper contends lhat Hwanwoong and YanDi-ShenNong played the role of civilization in the same era [Go-Choseon], the first volume of Samgukusa is philologically very valuable material for research on the origin of Korean nation and its ancient history.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2959-2961
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• 2000

인터넷의 발전으로 기존의 가정 자동화의 개념이 변화되어 단순한 제어의 범위를 넘어 정보제공, 원격관리 등의 서비스와 연계되어 통합적인 흠 네트워크의 구축이 요구되고 있다. 이에 관련하여 기존에 포설된 망을 이용하여 흠 네트워크를 구축하는 방안으로 최근 들어 전력선을 이용한 통신 시스템 개발에 대한 관심이 고조되고 있다. 지금까지는 변압기 2차측에 설치되는 라우터나 전력신호와 통신 신호를 커플링하는 커플러 개발 등의 하드웨어에 대한 연구와 흠 네트워크 관리를 위한 웹브라우저의 개발에 대한 연구가 진행되어 왔다. 그러나 실제 흠 네트워크 제어를 위한 운영체제에 대한 연구는 미흡한 실정이다. 따라서 본 논문에서는 전력선 통신망 이용환경 하에서의 가전 네트워크 및 인터넷을 포괄하여 관리할 수 있는 전용 운영체제의 구성과 흠 네트워크를 위한 전력선 네트워크 어댑터의 기본 구조를 고찰 하였다.