• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.235-243
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• 2005

Line constants of the catenary system are estimated. The harmonic current that the Korean Train Express (KTX) injects into the catenary is measured to precisely analyze the harmonic effects. The Korean high-speed railway system is modeled by estimated and measured results. The system model is applied for predicting the harmonic effects. The simulation results from the system model are compared to field test data concerning the total harmonic distortion (THD). The reliability of the system model is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기설비전문위원
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• pp.53-55
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• 2005

Because of the continuous growth of energy consumption and also the tendency to site power lines and pipelines along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. The lightning strokes collected by an electric substation or power line tower might cause arcing through the soil to an adjacent gas pipeline. This paper gives the review of the breakdown mechanism and the standards of separation distance between lower and pipelines.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.223-226
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• 2002

This paper studies the scope and text summary of international standards related to adjustable speed d.c. drive systems, especially IEC 61800-1 and IEC 61136-1. IEC 61800-1 applies to general purpose adjustable speed d.c. drive systems which include the power conversion, control equipment, and also a motor or motors. This standard applies to power drive systems connected to line voltages up to 1kV a.c., 50Hz or 60Hz. IEC 61136-1 provides alternative methods for specifying ratings for semiconductor power convertors for adjustable speed electric drive systems, particularly for d.c. motor drives.

• Current Optics and Photonics
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• 제3권5호
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• pp.451-457
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• 2019

Laser processing using holograms can greatly improve processing speed, by spatially distributing the laser energy on the target material. However, it is difficult to reconstruct an image with arrays of closely spaced spots for laser processing, because the specklelike interference pattern prevents the spots from getting close to each other. To resolve this problem, a line target was divided in two, reconstructed with orthogonally polarized beams, and then superposed. Their optical reconstruction was performed by computer-generated holograms and a pulsed laser. With this method, we performed two-dimensional (2D) laser drilling of polyimide film, with a kerf width of $20{\mu}m$ and a total processing length of 20 mm.

• Imaging Science in Dentistry
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• 제35권1호
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• pp.25-31
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• 2005

Purpose : To evaluate the stability of the segmental occlusal plane and anatomical line as the reference line for measuring the mesiodistal tooth angulation in panoramic radiography and to determine the mean angle and the range of the mesiodistal tooth angulation in Korean population with normal occlusions. Materials and Methods : Twenty nine subjects (15 men, 14 women) with normal occlusion were selected. A total of 29 panoramic radiograms were taken at normal head position and then 10 images of 5 subjects selected were repeatedly taken with repositioning 2 times at each of the head down (V-shaped occlusion) and up (horizontal occlusion) for evaluation of stability of adopted reference lines by using PM2002CC (Planmeca, Finland). The images were traced with adoption of two test reference lines and the long axes of the teeth. The mesial angles formed by each reference line and the long axes of the teeth were measured and analyzed. Results : With anatomical reference line, the mesiodistal tooth angulations of the molars showed the significant difference by over 5 degree between the normal and each changed head position. With segmented occlusal reference line, deviations of mesiodistal tooth angulations by the two changed head positions were less than 1 degree. The means, standard deviations, and maximum and minimum values of mesiodistal tooth angulations to segmental occlusal reference line on panoramic radiography were determined. Conclusion : It would appear that mesiodistal tooth angulations to segmental occlusal plane as reference line in panograms are predictable as standards of normal occlusion and useful for evaluation of tooth arrangement between adjacent teeth.

• 벤처창업연구
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• 제8권3호
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• pp.147-155
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• 2013

본 연구의 목적은 생산현장의 생산성향상을 위한 낭비를 분석하여 객관적이고, 과학적으로 현장낭비를 종합적으로 분석하여 이를 개선함으로써, 최적의 생산 라인을 구축하여 원가절감을 하고, 나아가 기업경쟁력을 강화하고자 한다. 많은 기업들이 현장의 낭비를 분석하는데 있어서 명확한 로드 맵이 없어 기존의 IE(Industrial Engineering)기법과 응용 IE기법을 기업현실과 상황을 고려하여 각각 활용, 그 성과측면에서의 아쉬움을 가지고 있다. 본 연구의 생산혁신 프로세스는 조립라인, 가공라인, 자동화 라인 등에 존재하는 모든 낭비를 분석할 수 있도록 추진 단계별로 고전 IE 및 응용 IE 기법을 체계적으로 정리함으로써 생산현장의 낭비를 종합적으로 분석/파악하여 전체 낭비가 얼마나 존재하며, 이를 개선하기 위한 선택과 집중을 기할 수 있도록 개선성과를 극대화하고, 개선활동계획 수립에 기여하고자 함이다.

• 한국화재조사학회학술대회
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• 한국화재조사학회 2011년도 제21회 춘계학술대회
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• pp.77-97
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• 2011

본 논문에서 옥외용 LED 조명의 전기화재 및 감전 위험성 평가에 대하여 연구하였다. 옥외용 LED 조명관련 법 규정에 대하여 검토하였으며, LED 조명의 외형과 구조에 대하여 분석하였다. 또한, LED 조명에 대한 주수실험, DC 전로의 선간 단락, 손상된 피복의 선간 절연파괴, 과전압 유입, 건전상 및 수중에서의 DC 전로의 누전 실험을 수행하였다. 실험 결과로부터, LED 조명에서의 이상 조건에 의한 전기화재나 감전사고의 위험성이 있음을 확인할 수 있었으며, 전기안전을 위한 보호장치와 절연형 컨버터의 사용이 요구된다. 본 연구결과는 LED 조명의 전기안전 확보를 위한 제 규정의 개선과 전기사고의 조사에 도움이 될 것으로 기대된다.

• 대한치과교정학회지
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• 제18권2호
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• pp.459-474
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• 1988

두부(頭部)X선규격사진법(線規格寫眞法)이, 치과교정학(齒科矯正學)에 도입(導入)된 이래(以來), 악안면두개(顎顔面頭蓋)의 형태학적연구(形態學的硏究)에 획기적(劃期的) 수단(手段)으로서 응용(應用)되여, 치과교정학(齒科矯正學)에 관(關)한 증례분석(症例分析) 및 치료평가(治療評價)에 중요(重要)한 방법(方法)으로서 채용(採用)되고 있다. 저자(著者)는 정상교합(正常咬合)의 한국인성인남녀(韓國人成人男女)의 두부(頭部)X선규격사진(線規格寫眞)을 이용(利用)하여, 표준치(標準値)의 산정(算定) 및 일본인(日本人), 백인(白人)과의 비교검사(比較檢詐)를 행(行)하였다. 자료(資料)로서는 성년남자(成年男子) 50명(名) 여자(女子) 계(計) 100명(名)을 촬영(撮影)하여 자료(資料)로 하였다. 연구방법(硏究方法)으로서는 6종(種)의 분석법(分析法)을 이용(利用)하여 계측(計測)하였으며, 저자(著者)가 설정(設定)한 U-1 lluxley line angle을 가(加)한 58종(種)의 계측항목(計測項目)에 대(對)하여 계측(計測)검토(檢討)하였으며, 다음과 같은 결과(結果)를 얻었다. 1. 각분석법(各分析法)에 의한 한국인성인(韓國人成人)의 표준치(標準値)를 남녀별(男女別)로 산출(算出)하였으며, 치과교정(齒科矯正) 진단(診斷)에 응용(應用)하기위하여 합리적(合理的)이라고 생각되는 14계측항목(計測項目)을 선정(選定)하여 표준편차도표(標準偏差圖表)와 cephalometric profilogram을 작성(作成)하였다. 2. 본자료(本資料)에서의 남녀간(男女間)의 성차(性差)의 유의성(有意性)은 각도적계측항목(角度的計測項目)에서는 없었으며, 거리적계측(距離的計測)에 있어서는 유의차(有意差)가 나타났다. 3. 일본인(日本人)과의 비교(比較)에 있어서는 남녀(男女)의 gonial angle, 남성간(男性間)의 interincisal angle에서 유의차(有意差)가 나타났으나, 평균치차(平均値差)가 많지않았으며, 한국인(韓國人)과의 유이성(類以性)이 강(强)하게 나타났으며, 여성(女性)에 있어서는 남성(男性)보다 더욱 강(强)한 유이성(類以性)이 나타났다. 4. 백인(白人)과의 비교(比較)에 있어서는 angle of convexity, mandibular plane angle, Y-axis angle, interincisal angle, L-I to mandibular plane angle에서 유의차(有意差)가 나타났으며, 한국인(韓國人)은 백인(白人)보다 convex type의 안예(顔猊)였다. 5. 신설계측항목(新設計測項目)으로서 upper incisal to Huxley line angle을 설정(設定)하였으며, upper incisal axis와 X-Y axis가 거의 평행상태(平行狀態)인것이 발견(發見)되었다.

• 한국IT서비스학회지
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• 제8권4호
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• pp.141-150
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• 2009

There are no objective standards for selection and improvement of SLA evaluation metrics for IT service. In this study, we analyze the current IT maturity models for selection and improvement of the metrics and then we derive them according to the maturity levels and propose the redesigned maturity model. To verify whether the model is applicable, we execute a case study based on the D company. We apply the proposed evaluation metrics of the maturity models to the D company and evaluate the metrics. We select a proper level of the D company and an improvement line after measuring evaluation metrics in the maturity level 2. We propose improvement guidelines of evaluation metrics which score is less than the improvement line's and derive SLA evaluation metrics. By using the SLA evaluation metrics for a year, we prove that the way of selection and improvement is useful.

• 한국주거학회논문집
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• 제15권6호
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• pp.99-106
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• 2004

The purpose of the study is to propose architectural design standards of the cafeteria planning in educational facilities. In the spatial organization planning, the preferred location of the cafeteria is on the first floor and the types of the floor plan are followed by the forms and space structure of the school building. The area of the cafeteria is related to the size of seating area per person. The direction must sublate northern faced. In interior moving lines for service, the arrange of dining tables has to reflect distance of dining tables or location of pillars. The dining space should better have more than two entrances in terms of occupancy type and convenience. Thus the serving line has to be planed thoughtfully by various factors to avoid confusion caused in serving process. In multipurpose use of the cafeteria, it is feasible when hygiene and management is considered.