• 전력전자학회논문지
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• 제24권3호
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• pp.153-160
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• 2019

This study proposes a current source-type pulse generator to improve output voltage and current waveforms under a capacitively coupled plasma (CCP) system. The proposed circuit comprises two parallel-connected current source-type converters. These converters can satisfy the required output waveforms of plasma processing. The parallel-connected converters operate without reverse current fault by applying a time-delay control technique. Conventional voltage source converters based on pulse power supply exhibit drawbacks in short-circuit current, and problems occur when they are applied to a CCP system. The proposed pulse power supply based on a current source converter fundamentally solves the short-circuit current problem. Therefore, this topology can improve the voltage and current accuracy of a CCP system.

• Spatial Information Research
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• 제23권6호
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• pp.43-55
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• 2015

현재 우리나라는 기관별 업무활용을 위해 각자의 격자체계에 따라 자료가 구축되어 있어 상호 연계가 되지 않고, 자료 활용 및 접근성의 한계 등의 문제점이 발생하고 있다. 본 연구에서는 이러한 문제점을 해결하기 위해 국가적인 차원에서의 국가격자체계와 격자데이터를 표준안을 검토하고, 장단점을 파악하고자 하였다. 국내외 격자체계 활용현황을 조사하고 격자데이터 활용문제점 개선을 위해 관계기관 및 관련분야 연구자들을 대상으로 수요조사를 실시하였다. 그 결과 격자데이터를 필요로 하는 사용자가 쉽게 접근가능하고, 격자데이터의 공유방안과 상호호환을 위한 데이터 제공형태 및 방법도출 등 국가격자데이터 통합관리체계를 위한 국가격자체계안을 제시하였다.

• 대한디지털의료영상학회논문지
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• 제14권2호
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• pp.47-56
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• 2012

Amount of radiation exposure by seeing through fluoroscopy examination while is many patient exposure administration and unprepared misgovernment be. In this study, abdominal fluoroscopy during the scan, the dose and image quality change according to the use of grid and added filter optimized by measuring the test condition is proposed. Uses seeing through fluoroscopy examination equipment of Image Intensifier of Easy Diagnost Eleva (Philips), under tube type and uses Human phantom and measures average area dose according to grid insertion existence and nonexistence and added filter kind change. Measure sum of 29 organ dose and effective dose through PCXMC imagination simulation program and image J program through noise, SNR, image distortion was measured. Resolution, sharpness, and analyzed using the MTF curves. Fluorography the grid to insert the filter thickness and thickening and increased the average area dose and organ doses and effective dose. In the case of spot examination, when inserted grid, average area dose and organ dose and effective dose increased. Filter thickens the average area dose decreased, but the organ doses and effective dose were increased when use 0.2mmCu+1mmAl filter, decreased slightly. Noise and SNR measurements without inserting the gird, if you do not use the added filter was the lowest and when measure the distortion, 0.1mmCu+1mmAl filter was no difference of image quality in case insert grid was judged that when did not use occasion added filter that do not use grid, difference of image quality does not exist. Did not show a big difference, according to the grid and uses of the added filter sharpness, and resolution. Patient dose increases with factors that reduce the quality of the image so reckless grid and the use of the added filter when abdominal fluoroscopy examination should be cautious in using.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2000년도 춘계학술대회 논문집
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• pp.120-125
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• 2000

• 한국도로학회논문집
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• 제19권3호
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• pp.31-43
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• 2017

PURPOSES : The objective of this study is to verify the effect of fiber grid reinforcement on the long-term performance of asphalt pavement overlaid on old concrete pavement by performing field investigation, laboratory test, and finite element analysis. METHODS : The reflection cracking, roughness, and rutting of fiber grid reinforced overlay sections and ordinary overlay sections were compared. Cores were obtained from both the fiber grid reinforced and ordinary sections to measure bonding shear strength between the asphalt intermediate and asphalt overlay layers. Fracture energy, displacement after yield, shear stiffnesses of the cores were also obtained by analyzing the test results. Finite element analysis was performed using the test results to validate the effect of the fiber grid reinforcement on long-term performance of asphalt pavement overlaid on the old concrete pavement. The fatigue cracking and reflection-cracking were predicted for three cases: 1) fiber grid was not used; 2) glass fiber grid was used; 3) carbon fiber grid was used. RESULTS : The reflection-cracking ratio of fiber grid reinforced sections was much smaller than that of ordinary sections. The fiber grid reinforcement also showed reduction effect on rutting while that on roughness was not clear. The reflection-cracking was not affected by traffic volume but by slab deformation and joint movement caused by temperature variation. The bonding shear strength of the fiber grid reinforced sections was larger than that of the ordinary sections. The fracture energy, displacement after yield, and shear stiffnesses of the cores of the fiber grid reinforced sections were also larger than those of the ordinary sections. Finite element analysis results showed that fatigue cracking of glass or carbon fiber grid reinforced pavement was much smaller than that of ordinary pavement. Carbon fiber grid reinforcement showed larger effect in elongating the fatigue life of the ordinary overlay pavement compared to glass fiber grid reinforcement. The binder type of the overlay layer also affected the fatigue life. The fiber grid reinforcement resisted reflection-cracking and the carbon fiber grid showed the greater effect. CONCLUSIONS :The results of field investigation, laboratory test, and finite element analysis showed that the fiber grid reinforcement had a better effect on improving long-term performance of asphalt pavement overlaid on the old concrete pavement.

• 한국유기농업학회지
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• 제17권3호
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• pp.307-326
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• 2009

The present study suggests a concept of resources circulation type agriculture and a concept of a livestock zone related to it and evaluated economical efficiency about a possibility of the resources circulation type livestock zone based on the concept. As a result, when the resources circulation type livestock zone is operated in an area of 1,300ha, it was evaluated that the profit of 11,244 hundred thousand won per year is generated, compared to the conventional agriculture. When light and heat expenses and roughage of Hanwoo production, production of TMR forage as well as income of the energy and composting business of livestock manure at the recycling center were considered in addition to that, it was judged that the present zone development bushiness has enough business feasibility. However, it is necessary that the support regulations, etc. is constructed so that all produced compost byproducts are used at farmhouses and the system related to facility investment assurance and assistance of operating expenses is maintained. It is thought that the complement of a system is also necessary so that energy or power generation expenses can be operated in the same conditions as other new & renewable energy, and the nation's purchase of carbon credits(CDM) is investigated and systemized in the early period, and construction of a revitalization plan of the business through budget securing of the Ministry of Agriculture and Forestry related to the trade of CDM and carbon emission rights is also a business that should be urgently developed. In the future, the change of an outside environment will further promote use of the energy. Also, as people, who don't know agriculture. farm village, increase day by day because of population concentration in a city, an opportunity that can new added value through experience tourism or educational programs utilizing them is increasing. Accordingly, if programs utilizing social characteristics, such as utilization as a space of tourism. leisure. experience, system construction of bio-energy and system construction that Micro Grid or Smart Grid as a dispersed storage and generation system is stabilized, are constructed, it can be said that revitalization or success conditions of the zone is further achieved.

• 디자인학연구
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• 제18권3호
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• pp.191-198
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• 2005

컴퓨터 시스템에서 화면상의 복수의 항목 중에서 특정 항목을 선택하고 실행하기 위해 가장 널리 사용되는 도구가 메뉴인데 정보량이 급격하게 증가하면서 동적 메뉴와 같은 새로운 메뉴가 많이 개발되고 있다. 본 연구에서는 실험을 통해 풀다운(pull-down) 메뉴, 피시아이(fisheye) 메뉴, 그리드(grid) 메뉴의 객관적 수행도(수행시간, 오류)와 사용자의 주관적 평가(단순성, 사용 효율성, 친근성, 전반적 선호도)를 비교분석 하였다. 중간 수준의 메뉴 항목이나 작은 화면을 고려하여 개발된 그리드 메뉴는 메뉴 항목의 수가 중간 수준(50개)이나 많은 수준(100개)일 때, 풀다운 메뉴와 피시아이메뉴보다 수행시간에 있어 효율적인 것으로 나타났다. 메뉴항목의 수와 수행시간 사이에는 모든 메뉴가 비례관계를 보였으나 그리드 메뉴가 가장 둔감하게 반응하였다. 풀다운 메뉴와 그리드 메뉴는 피시아이 메뉴에 비해 보다 간단하고, 친근하고, 효율적인 것으로 평가되었으며 42.3 퍼센트의 피험자가 그리드 메뉴가 메뉴들 중에서 가장 우수하다고 평가하였다. 결론적으로 그리드 메뉴는 메뉴 항목의 수가 적거나 중간 정도의 수준일 때 효율적인 디자인 대안으로 선정될 수 있을 것으로 판단되며 모바일 기기에서의 효율성을 살펴보기 위해선 보다 심도 깊은 연구가 요구된다.

• 한국주거학회논문집
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• 제26권6호
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• pp.139-146
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• 2015

In this study, the plane type of main building relics of unified Silla period house site which excavated in Gyeongju city after 1990s was classified and the architectural characteristic of them was investigated. The chronology of building relics in Silla capital city site was mostly known as 8-9th century, and by standard of column arrangement, the plane types of them could be classified as grid type, front veranda-grid type, outer column type. The outstanding characteristic of plane is wide span and open front veranda. In most relics the span were over 4 meters, and inner foundations for small post and strip foundation were found between columns. The front veranda added type buildings were composited of enclosed main room and open front veranda, and column arrangement of them dose not fall into line in most case. Thus it thought that the structures of enclosed main room and open front veranda were independent. The interior space of enclosed main room were divided two rooms by partition wall in some case. In this case, one room is enclosed by wall, and the other room has open front side. This plane is considered for the pleasant life in cold winter and hot summer.

• 한국태양에너지학회 논문집
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• 제37권6호
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• pp.1-12
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• 2017

The DC link of Grid-Connected 3-Phase 3-Level T-type Photovoltaic PCS (PV-PCS) consists of two series connected capacitors for using their neutral voltage. The mismatch between two capacitor characteristics and transient states happened in load change cause the imbalance of neutral voltage. As a result, PV-PCS performance is degraded and the system becomes unstable. In this paper, a mathematical model for analyzing the imbalance of neutral voltage is derived and a compensation method using offset voltage is proposed, where offset voltage adjusts the applying time of P-type and N-type small vectors. The validity of the proposed methods is verified by simulation and experiment.

• 한국공간구조학회논문집
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• 제7권3호
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• pp.125-132
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• 2007

본 연구의 주목적은 공간그리드의 조형요소로서 3차원 유닛의 역할과 구성을 탐구하는 것이다. 따라서 공간그리드와 3차원 유닛의 상호관계와 역할, 유닛의 유형 및 구성방식과 이에 영향을 미치는 요인들이 파악된다. 또한 각각의 형태적 특성 및 조합이 공간그리드 전체의 형상에서 드러내는 효과를 확인하여 전반적인 형태구성의 틀을 제시하고자 한다.