• 한국항공우주학회지
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• 제43권11호
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• pp.952-962
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• 2015

효율적인 추진기관 개발을 위해 여러 종류의 고도 보정 노즐에 대한 연구가 진행되고 있다. 본 논문에서는 향후 듀얼 벨 노즐 연구를 위한 기초자료로서의 활용을 위해 독일 DLR에서 수행한 연구내용을 바탕으로 듀얼 벨 노즐의 주요 특성을 조사하고 핵심 변수를 도출하였다. DLR은 다양한 실험을 통해 변곡각과 천이 NPR은 비례한다는 것과 확장부 길이와 측하중은 비례하지만 천이 NPR과 천이 지속시간과는 반비례한다는 것을 밝혔다. 성능 예측 과정을 통해 노즐의 형상이 결정될 수 있고 요구 성능에 맞게 변수간의 최적화가 필요하다.

• 한국자기학회지
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• 제18권6호
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• pp.217-220
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• 2008

Rare-earth iron oxide $ErFe_2O_4$의 다결정체 시료의 자기적 특성을 연구하였다. 단일상의 다결정체 $ErFe_2O_4$ 시료를 CO/$CO_2$ gas 분위기에서 고체상태반응법으로 합성하였다. X-ray diffraction 측정을 통해 $ErFe_2O_4$ 시료는 space group R3m Rhombohedral 구조를 가지며, 온도에 의존하는 magnetization 측정을 통해 250 K에서는 자기적 전이가, 220 K에서는 구조적 전이가 일어나는 2단계 상전이 현상을 확인하였다.

• 한국터널지하공간학회 논문집
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• 제23권1호
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• pp.1-12
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• 2021

Tunnel boring machine (TBM)의 설계에 있어서 지반과 직접적으로 맞닿아 절삭을 담당하는 커터헤드의 설계에 따라서 장비의 굴진효율이 달라지게 된다. 디스크커터는 배치되는 위치에 따라 센터 커터 존, 이너 커터 존, 트렌지션 커터 존으로 구분된다. 기존에도 페이스커터의 최적 절삭조건을 규명하기 위한 연구는 많이 진행되어 왔으나, 트렌지션 커터의 최적 절삭조건을 규명하기 위한 연구는 상대적으로 미진하였다. 본 연구에서는 트렌지션 커터의 최적의 절삭조건을 규명하기 위해 개별요소법 수치해석을 수행하고 트렌지션 커터 사이의 각도에 따른 비에너지 곡선을 작도하여 최적 절삭조건을 알아보고자 하였다. 수치해석 결과 전이영역에서 최소 비에너지를 보이는 트렌지션 커터 사이의 각도 9°인 것으로 확인되었다. 이를 트렌지션 커터의 경사각에 따라 3가지 영역으로 구분하고 영역별 디스크커터 사이의 각도와 비에너지를 정리한 결과 트렌지션 커터의 경사각이 커질수록 최적 비에너지를 보이는 트렌지션 커터 사이의 각도는 10°에서 8°까지 점차 감소하는 경향을 보였다. 이러한 결과는 기존에 사용되고 있는 트렌지션 커터의 설계 결과와 유사한 경향으로써, 본 연구의 결과를 밑받침한다.

• 대한가정학회지
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• 제37권10호
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• pp.43-54
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• 1999

The purpose of this study is to clarify the transition and terminology of sanitary spaces in Korean houses, based on the analysis of novels. The resets are as follows. The sanitary space huts been developed in all aspects including locations and facility levels. Duikan, Pyunso, Tongsi, Whajangsil, and Yoksil were the terminology of sanitary space that appeared often in the novels. Before 1930, the word most frequently mentioned was Duikan. Whajangsil and Yoksil appeared shortly between 1930-1750. Duikan, Pyunso, and Tongsi were presented again between 1950-1970. Whajangsil and Yoksil were substituted for most other words after 1980. Other than the usual function of sanitary space, these areas also used as hiding spaces and places where one could observe others secretly. The sanitary spaces in most novels were located behind kitchens, nearby fences or stables and were typically unpleasant places with a messy dung tub, no lighting system, and a shed-like construction.

• 한국실내디자인학회논문집
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• 제34호
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• pp.69-77
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• 2002

The purpose of this study is to recognize the living space and life pattern transition which is expressed in the modernization course with the analysis of the Jeju rural houses. For this study, I choose 72 residences examples in 8 villages as the subjects which are changed by the spontaneous purpose of the inhabitants who live in Jeju area were chosen as the subjects. As for the research method, after visiting the subject residence directly, and the field study such as the actual estimation, observation and interview were performed.The conclusion of the study with these purpose are as follows. First, The opened spatial composition of the sitting-inclination is composed of the form which has the individual opened room and living room with the mechanism to grant the flexibility to the limited space and the structure for enduring the much-humid oceanic climate. Second, The life pattern shows the sitting life which usually uses the an-bang and living room with the seasonal change.

• 로봇학회논문지
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• 제1권2호
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• pp.107-116
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• 2006

We propose a planning algorithm to automatically generate a robust behavior plan (RBP) with which mobile robots can achieve their task goal from any initial states under dynamically changing environments. For this, task description space (TDS) is formulated, where a redundant task configuration space and simulation model of physical space are employed. Successful task episodes are collected, where $A^*$ algorithm is employed. Interesting TDS state vectors are extracted, where occurrence frequency is used. Clusters of TDS state vectors are found by using state transition tuples and features of state transition tuples. From these operations, characteristics of successfully performed tasks by a simulator are abstracted and generalized. Then, a robust behavior plan is constructed as an ordered tree structure, where nodes of the tree are represented by attentive TDS state vector of each cluster. The validity of our method is tested by real robot's experimentation for a box-pushing-into-a-goal task.

• 한국주거학회논문집
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• 제12권3호
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• pp.21-28
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• 2001

The purpose of this study is to find Korean tradition of residential space which continues since 1960s. Analysis of house works of contemporary architects on the foundation spatial characteristics of Korean. Traditional residence show that the trend and methods of embodiment of tradition in present architecture. The result of analysis could be summarized as follows. First, most of contemporary architects separate a house into two Chae-An Chae and Sa Rang Chae. Second, spatial flows in contemporary house works are very active through transition spaces just as traditional residence. Third, positive An Ma Dang takes on introversion, extroversion and continuity of space and also plays an important role in a house.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1209-1212
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• 1999

The entropies and chemical potentials of hard-sphere solutes solvated in hard-sphere solids were calculated by Monte Carlo method using the radial free-space distribution function. This method is based on calculating the entropy by comparing the free volume of a molecule with that of an ideal gas, and is applicable even when the size of solute is very large and the solvent is a solid. When the diameter of hard-sphere solute is small the solute molecule behaves as like as a fluid in solid structures, but when the diameter of solute becomes large, a fluid-to-solid phase transition takes place. The fluid-to-solid phase transition occurs at the region of the smaller size of solute with the more increase of solvent density. The least square fit values of analytical form of the radial free-space distribution functions of solute molecules are presented for future uses.

• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.67-72
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• 2005

In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this paper, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition equations. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.344-349
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• 2005

In conventional small signal stability analysis, the system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of the state matrix. However, when a system contains switching elements such as FACTS equipments, it becomes a non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is performed by means of eigenvalue analysis of the system's periodic transition matrix based on the discrete system analysis method. In this paper, the RCF (Resistive Companion Form) method is used to analyze the small signal stability of a non-continuous system including switching elements. Applying the RCF method to the differential and integral equations of the power system, generator, controllers and FACTS equipments including switching devices should be modeled in the form of state transition equations. From this state transition matrix, eigenvalues that are mapped into unit circles can be computed precisely.