• 항공우주시스템공학회지
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• 제16권3호
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• pp.93-98
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• 2022

본 논문에서는 풀 브릿지 인버터의 비선형성을 고려한 단상 영구자석 동기 전동기의 오픈 루프 기동성을 개선하기 위한 구형파 전압 주입 기법을 제안한다. 일반적으로 단상 영구자석 동기 전동기는 3상 교류기와 달리 풀 브릿지 인버터를 채택하고 있으며 대칭 공극으로 자기 회로를 설계할 경우, 영토크 지점의 특정 위치에서 기동이 불가능할 수 있기에 비대칭 공극 설계가 요구된다. 이러한 단상 영구자석 동기 전동기의 구동 특성상 센서리스 운전 모드의 오픈 루프 제어시 기동 실패의 가능성이 상당히 높다. 본 논문에서는 이러한 문제를 해결하기 위해 인버터의 비선형성을 고려한 구형파 전압을 인가하여 기동 성능을 개선하는 기법을 제안하고자 한다. 제안한 알고리즘은 다수의 실험을 통해 타당성을 검증하였다.

• 한국강구조학회 논문집
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• 제25권3호
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• pp.267-278
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• 2013

본 연구에서는 개단면 리브를 갖는 보강판에서 발생하는 국부처짐과 모멘트가 정사각형 재하크기에 따라 어떻게 변화하는지 분석하여 이를 정형화 하고자 하였다. 평강 리브와 역T형 리브를 갖는 보강판에 대하여 각각의 재하크기별로 여러 가지 제원 변화에 따른 비율함수를 구하여 분석한 결과, 재하크기에 따라 기준 보강판의 값에는 차이가 있으나 리브 간격을 제외하고, 각 제원별 비율 함수에는 큰 차이가 없어 재하크기를 통합하여 표현 가능함을 알 수 있었다. 또한, 평강 리브와 역T형 리브의 차이도 크지 않아 리브 형태와 상관없이 통합한 하나의 함수로 사용 가능함을 알 수 있었으며, 이러한 통합된 하나의 비율함수식을 적용한 결과 상당한 정확도를 나타내었다. 본 연구에서 제안한 통합 함수를 L형 리브와 직사각형 재하에 적용한 결과, 타당한 결과를 나타내어 통합 함수의 적용성을 확인할 수 있었다. 따라서 본 연구에서 제안한 통합 비율함수식을 이용하면, 개단면 리브를 갖는 보강판에서 발생하는 국부처짐과 국부 모멘트 결과를 간편하게 얻을 수 있을 것으로 판단된다.

• 교육녹색환경연구
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• 제10권1호
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• pp.1-9
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• 2011

In order to solve the current shortage of parking spaces, and redesign the main gate area of the U University, the research investigated some cases of other schools located in Seoul which actively constructed multi-purpose building structures. Those schools are considered to be good samples showing their efforts to fulfill the needs of more parking spaces in their campuses, and to cover with the growing needs of multi-functioned facilities accommodating services of academic affairs, reading room spaces, and amenities. With the investigation, the research finded out the current trends of campus developments from the sample schools, such as underground parking facilities connected with multi-purpose buildings along the main arteries of campuses. Following the trends the research thoroughly examined the present conditions of our school and tried to make some possible alternatives for the facilities. Under the conditions, the research suggested 1)to construct underground parking lots accepting around 1,000 cars under the ivory tower square located in front of University Administration Building, 2)to develop a big-scaled open square at the university main gate, and 3)to build a multi-purpose structure along the main street of the campus, which included administration services, studying spaces, and some commercial facilities.

• Wind and Structures
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• 제17권3호
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• pp.245-262
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• 2013

The flow interaction between two identical neighboring twin square prisms in a staggered arrangement in an open terrain was investigated experimentally. The downwind prism was mounted on a rigid-aeroelastic setup in an open-terrain boundary layer flow to measure its acrosswind root-mean-square responses and aerodynamic damping ratios. By varying the relative location of the upwind prism and the Scruton number associated with the downwind prism, the acrosswind aeroelastic behavior of the downwind prism was analyzed and compared to that of an isolated one. Results showed that the acrosswind root-mean-square response of the downwind prism could be either suppressed or enhanced by the wake flow produced by the neighboring upwind prism. Besides the assessment of the wake effect of the downwind prism, finally, regressed relationships were presented to describe the variation of the aerodynamic damping ratio so as to predict its acrosswind fluctuating response numerically.

• Architectural research
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• 제9권1호
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• pp.19-30
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• 2007

This study explores the issue of campus expansion of an urban university using an in-depth case study of New York University in New York City, USA. It investigates the physical pattern and development mechanism of the campus expansion process on a city grid structure. The three elements that characterize NYU's recent campus expansion, are (1) the university's commitment to building a student community around a public open space on a subway network, (2) four types of property acquisition and building development practiced by the university with private developers for space leasing, building renovation and development under changing local development circumstances, and (3) the city's initiative for attracting the private sector whose development activities influence the university's development dynamics. These findings suggest that the expansion planning of an urban university, due to its location in a city, should be placed on a local planning agenda, which can positively contribute to public goals through the collaborative engagement of the private and public sectors.

• 한국운동역학회지
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• 제17권3호
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• pp.115-124
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• 2007

The purpose of this study was to analyze the kinematics variables of upper limb joint during forehand stroke by swings patterns. Eight high school tennis players were chosen for the study, who have never been injured for last six months, in Busan. They performed horizontal swing and vertical swing that it was done each five consecutive trial in the condition of square, semi-open and open stance. It was filmed by 6 video camera and used with 3-dimensional motion analyzer system. The following kinematic variables were analyzed in relation to angle of joint(shoulder, elbow and wrist joint). The conclusion were as follow: 1. The angle of right shoulder joint represented all event that both swing were shown similar pattern in swing type and stance pattern. 2. All event in the angle of elbow joint had consistent with that except E2, horizontal and vertical swings in square stance. 3. All event in the angle of wrist joint was show to similar pattern except E2, horizontal and vertical swing in open stance.

• 한국수학교육학회지시리즈A:수학교육
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• 제43권3호
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• pp.275-289
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• 2004

The purpose of the study is to investigate how children and preservice teachers would make a progress in solving the open-problems related to area. In knowledge-based information age, information inquiry, information construction, and problem solving are required. At the level of elementary school mathematics, area is mainly focused on the shape of polygon such as square, rectangle. However, the shape which we need to figure out at some point would not be always polygon-shape. With this perspective, many open-problems are introduced to children as well as preservice teacher. Then their responses are analyzed in terms of their logical thinking and their understanding of area. In order to make students improve their critical thinking and problem solving ability in real situation, the use of open problems could be one of the valuable methods to apply.

• 한국조경학회지
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• 제42권6호
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• pp.111-123
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• 2014

도시광장은 지역사회 모임이나 시장, 공연, 정치집회 및 기타 이벤트 등 다양한 활동이 행해지는 곳으로, 도시 내에서 다양한 유형으로 나타난다. 그럼에도 불구하고 대부분의 도시광장은 광장 유형별로 다르게 나타나는 방문객의 이용행태 및 이용만족에 대한 고려가 미비한 채 획일적으로 계획되어왔다. 본 연구에서는 서울에 위치한 일반광장 중 중심대광장을 대표하는 광화문광장과 근린광장을 대표하는 금빛공원광장을 중심으로 방문객 만족도에 영향을 미치는 설계요인과 세부 요소를 분석하여 도시광장 유형별 설계 시 중점적으로 고려해야 하는 방안을 제안하였다. 각 광장에서 수집한 설문조사 결과는 요인분석, 회귀분석, 퍼지이론 등을 이용하여 분석하였다. 연구결과를 요약하면, 첫째, 도시광장 설계요소 만족요인은 어메니티, 이용성, 공간특성, 문화성, 쾌적성요인으로 구분되었다. 둘째, 광화문광장의 공간이용 만족도에 영향을 미치는 요인은 어메니티요인, 쾌적성요인, 공간특성요인 순으로 나타났으며, 금빛공원광장의 공간이용 만족도에 영향을 미치는 요인 쾌적성요인, 어메니티요인, 이용성요인, 공간특성요인 순으로 나타났다. 셋째, 도시광장의 설계요소에 대한 만족요인별 만족순위를 퍼지이론을 통해 비교한 결과, 광화문광장은 어메니티요인 중 광장의 청결도에 대한 만족도가 가장 높게 나타났다. 금빛공원광장은 쾌적성요인 중 광장의 수목에 대한 만족도가 가장 높게 나타났다. 이와 같이 본 연구에서는 중심대광장과 근린광장의 이용객 만족도에 영향을 미치는 설계요소를 비교하였다. 연구의 결과는 이용객 만족을 고려한 도시광장 설계 및 계획에 기초자료로 사용될 수 있을 것으로 기대된다.

• 화약ㆍ발파
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• 제19권1호
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• pp.71-84
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• 2001

Korean peninsula has the most mountainous areas such as mountains and hilly country, and it is surrounded by the sea on all sides but one. In this respect, a large scaled construction works have frequently been conducted. However, it is not easy to porform a large scale blasting work without giving any harm to houses or facilities nationwide. Therefore, blasting work becomes more closely related to maintenance thing due to the development of the downtown or a large structure for key facilities. Many researches on blast in the open space and tunnel blasting have been conducted. On the contrary, research on underwater blasting operations is comparatively scanty even though much more necessity of marine development is required. In this respect, this study aims to investigate the characteristics of underwater blasting operations and to make a comparative study with blast in the open space. As a result of examining into the characteristics during underwater blasting operations, the around oscillation in case of underwater blasting operations shows significantly low compared to that in case of blast in the open space, and this means that much more cautious altitude must be taken in designing underwater blasting operations compared to the design of blast In the open space. As a result of analysis on the difference between a square root and a cube root In the equation of estimating oscillations in the actual site, it is shown that it is shown to apply a square root for the estimation of oscillation at 60 meters in case of underwater blasting operations and at 22 meters case of general blast in the open space.

• 교육시설 논문지
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• 제19권3호
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• pp.3-12
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• 2012

Owing to generalization of design competitions since 1990s, various design methods was tried in elementary middle high school design competitions. Therefore, to analyze design characteristics of elementary middle high school is very meaningful. In this context, this study is the most important purpose for analyzing layout plans and their trends in prizewinners of elementary middle high school design competitions and for furnishing basic datum for next school design. The result of this study is following : (1) The layout patterns of school buildings are classified into 12 types. (2) Entrance design is divided into 6 types(structure, column and wall, open, half structure, general, and mixed type). (3) Square design is grouped into 7 types. (4) Pedestrian mall is sorted out 6 types(straight lineal, curve, curve and square, straight lineal and curve, and straight lineal and curve and square type). (5) Entrance types of vehicle and pedestrian are classified into 4 types(parallel, ㅡ separation, ㄱ separation, and opposite separation type) Analysis shows that the best applying for layout patterns of school buildings is ㄷ type and ㅌ type, for entrance design is structure type, for square design is ${\square}$ type and ${\bigcirc}$ type, for pedestrian mall is straight lineal and square type, and for entrance types of vehicle and pedestrian is parallel type.