• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.214-218
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• 1988

This paper suggests mathemathical engine model which can simulate generalized gasoline engine. Suggested engine model contains air/fuel inlet element, intake manifold, combustion, engine dynamics. In order to analyze a gasoline engine, physical characteristics of engine and steady state engine data should be controlled. In adaptation for abrupt change of circumstance or drive conditions, this model can analyze important physical phenomena in the intake manifold by computer simulation. This model can also evaluate statuses of drive under various working conditions precisely. Therfore, this model suggests basic datum to evaluate the engine system which are needed in designing and development of engine controller.

• 대한가정학회지
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• 제40권7호
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• pp.193-210
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• 2002

The purpose of this study is to identify the characteristics of physical setting of adult day care as a place for the elders and adult and to develop an basic understanding of the architectural program and physical setting for adult day care for the cognitively-impaired in the U.S.A. The data was collected from 13 Adult Day Care Centers(ADCC) from 2001 to 2002 by interview and the documents about those facilities. Physical environment should be viewed as an element in the care of individuals with dementia, and that the principles used to plan and design environment should be consistent with the principles used in providing other aspects of care. The results of the study provided the information about the best condition of physical setting of ADCC for the elderly with dementia. Memory Loss Adult Day Center and St. Ann Center for Intergenerational Care have better architectural program than other facilities. It is the hope of this study to provide guideline for design and care professionals with a first draft of a "sense-making" template and to slow own the progression of the disease by the appropriate physical environment.

• 한국조리학회지
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• 제17권5호
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• pp.42-56
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• 2011

본 연구는 커피전문점의 물리적 환경이 메뉴와 서비스 품질 평가에 미치는 영향력을 알아보고 커피전문점 이용자들이 인식한 물리적 환경이 고객만족에 영향을 미치는 결정변수를 제시하고자 하였다. 이를 위해 서울 경기지역에 거주하는 커피전문점 이용자들을 대상으로 조사하였으며 유효한 376부를 최종분석에 사용하였다. 연구 결과, 방문한 커피전문점의 물리적 환경을 높게 평가한 고객은 그렇지 않은 고객보다 메뉴와 서비스 품질을 높게 평가하였으며, 물리적 환경 요인이 고객 만족도에 긍정적인 영향을 미치는 것으로 나타났다. 특히, 물리적 환경 요인들 중에서 디자인이 고객만족에 가장 큰 영향을 주는 요인으로 나타났다. 이 결과는 커피전문점의 물리적 환경이 고객의 감정적인 만족과 긍정적인 태도를 유도하는 효과적인 운영 전략이 될 수 있음을 보여준다.

• 대한물리치료과학회지
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• 제3권2호
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• pp.981-987
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• 1996

Hand function evaluations are an important element of the assessment process in physical rehabilitation settings. The purpose of this study was to investigate hand function evaluation. Subjects consisted of 20 with spastic cerebral palsy(mean age = 9.8, SD = 1.6) and 20 with athetoid cerebral palsy(mean age = 9.6, SD = 2.3). Two groups of subjects were tested twice(pretest and posttest) by the JHFT to measure evaluations of hand function. These findings suggest that on four subtests - writing, card turning, large heavy objects and Stacking Checker-the spastic cerebral palsy perform significantly faster than athetoid cerebral palsy. But there were no significant differences between the pretest and posttest in spastic and athetoid cerebral palsy. To see the statistical differences in the experimental results was done using origin V. 3.0.

• 한국콘텐츠학회논문지
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• 제12권6호
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• pp.280-292
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• 2012

본 연구는 노인의 일상생활요인(사회적지지, 경제상태, 건강상태, 여가활동, 의사소통, 소비활동)이 영역별 삶의 만족도(자아존중, 대인관계, 정서상태, 신체건강, 경제생활) 에 미치는 영향을 파악하고자 하였다. 연구 대상은 경기도 지역에 거주하는 60세 이상 노인 280명을 대상으로 하였다. 자료 분석은 SPSS 18.0 프로그램을 이용하여 빈도분석, 요인분석, 신뢰도분석 및 t-test, ANOVA, 분산분석 등을 하였다. 연구결과는 첫째, 노인의 인구사회학적 특성에 따른 삶의 만족도 차이는 성별을 제외한 분야에서 통계적으로 유의한 차이가 나타났다. 둘째, 일상생활요인과 영역별 삶의 만족도 간에는 정적 상관관계가 있는 것으로 분석되었다. 셋째, 노인의 일상생활요인이 영역별 삶의 만족도에 미치는 영향은 자아존중 만족도는 사회적지지와 여가활동이 영향요인으로, 대인관계 만족도와 신체건강만족도의 경우 사회적지지, 여가활동 및 건강상태가 영향요인이었고, 정서상태만족도는 의사소통, 경제생활 만족도는 경제상태, 의사소통 및 소비활동이 영향요인인 것으로 분석되었다.

• 한국지반공학회논문집
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• 제34권12호
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• pp.59-69
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• 2018

한계평형법 이론들을 사용하기 위해서는 극한 파괴 상태에서 나타나는 파괴 전단면을 찾아야 한다. 강도 감소법에서는 유한요소해석의 수치해가 일정 반복 횟수 이내에 수렴하지 못하는 시점을 극한 파괴 상태로 정의한다. 하지만 Coupled Eulerian-Lagrangian (CEL)기법을 유한요소해석에서 사용하면 극한 파괴 상태에 도달하여도 수치해의 비수렴 상황이 발생하지 않으므로 이러한 정의는 사용하기 어렵다. 본 연구에서는 CEL 기법을 이용한 유한요소해석에서 지반의 극한 파괴 상태를 감지할 수 있는 객관적인 물리량 기준을 제시하였다. 비배수 조건의 연약지반이 연속기초 하중을 받는 경우 극한 파괴 상태에 해당하는 이론적 하중에서 소성 소산 에너지의 변화속도가 민감하게 변화함을 찾을 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.859-865
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• 2007

This paper presents a method to analyze the unbalance response of a high speed polygon mirror scanner motor supported by sintered bearing and flexible supporting structures by using the finite element method and the mode superposition method. The appropriate finite element equations for polygon mirror are described by rotating annular sector element using Kirchhoff plate theory and von Karman non-linear strain, and its rigid body motion is also considered. The rotating components except for the polygon mirror are modeled by Timoshenko beam element including the gyroscopic effect. The flexible supporting structures are modeled by using a 4-node tetrahedron element and 4-node shell element with rotational degrees of freedom. Finite element equations of each component of the polygon mirror scanner motor and the flexible supporting structures are consistently derived by satisfying the geometric compatibility in the internal boundary between each component. The rigid link constraints are also imposed at the interface area between sleeve and sintered bearing to describe the physical motion at this interface. A global matrix equation obtained by assembling the finite element equations of each substructure is transformed to a state-space matrix-vector equation, and both damped natural frequencies and modal damping ratios are calculated by solving the associated eigenvalue problem by using the restarted Arnoldi iteration method. Unbalance responses in time and frequency domain are performed by superposing the eigenvalues and eigenvectors from the free vibration analysis. The validity of the proposed method is verified by comparing the simulated unbalance response with the experimental results. This research also shows that the flexibility of supporting structures plays an important role in determining the unbalance response of the polygon mirror scanner motor.

• 한국구조물진단유지관리공학회 논문집
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• 제22권2호
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• pp.76-82
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• 2018

본 논문에서는 지점부 경계조건을 고려하여 단순보의 유한요소모델을 개선하는 기법을 제안하였다. 기존의 유한요소모델개선 기법은 주로 가속도 응답으로부터 추정된 동특성(고유진동수, 모드형상)을 이용하여 유한요소모델을 개선하였다. 이렇게 개선된 유한요소모델은 실제 구조물의 정적응답을 예측하기 어렵고, 잘못된 구조물의 물성치를 추정하는 문제가 발생한다. 제안된 기법은 먼저, 구조물의 처짐과 지점부 회전변위를 계측하여 지점부 경계조건을 간략화한 유한요소모델의 회전 스프링 강성을 정량적으로 추정한다. 회전 스프링 강성이 개선된 유한요소모델과 구조물의 동특성을 사용하여 구조물의 물성치를 추정함으로써 최종 개선된 유한요소모델을 구축된다. 제안된 유한요소모델 개선 기법과 기존 유한요소모델개선 기법을 수치해석 시뮬레이션을 통하여 비교 및 검증하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권3호
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• pp.243-259
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• 2016

The Richards equation for water movement in unsaturated soil is highly nonlinear partial differential equations which are not solvable analytically unless unrealistic and oversimplifying assumptions are made regarding the attributes, dynamics, and properties of the physical systems. Therefore, conventionally, numerical solutions are the only feasible procedures to model flow in partially saturated porous media. The standard Finite element numerical technique is usually coupled with an Euler time discretizations scheme. Except for the fully explicit forward method, any other Euler time-marching algorithm generates nonlinear algebraic equations which should be solved using iterative procedures such as Newton and Picard iterations. In this study, lumped mass and distributed mass in the frame of Picard and Newton iterative techniques were evaluated to determine the most efficient method to solve the Richards equation with finite element model. The accuracy and computational efficiency of the scheme and of the Picard and Newton models are assessed for three test problems simulating one-dimensional flow processes in unsaturated porous media. Results demonstrated that, the conventional mass distributed finite element method suffers from numerical oscillations at the wetting front, especially for very dry initial conditions. Even though small mesh sizes are applied for all the test problems, it is shown that the traditional mass-distributed scheme can still generate an incorrect response due to the highly nonlinear properties of water flow in unsaturated soil and cause numerical oscillation. On the other hand, non oscillatory solutions are obtained and non-physics solutions for these problems are evaded by using the mass-lumped finite element method.

• Geomechanics and Engineering
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• 제12권6호
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• pp.1021-1046
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• 2017

The assessment of slope stability is an essential task in geotechnical engineering. In this paper, a three-dimensional (3D) finite element analysis (FEA) was employed to investigate the performance of different shear pin arrangements to increase the stability of a soil block resting on an inclined plane with a low-interface friction plane. In the numerical models, the soil block was modeled by volume elements with linear elastic perfectly plastic material in a drained condition, while the shear pins were modeled by volume elements with linear elastic material. Interface elements were used along the bedding plane (bedding interface element) and around the shear pins (shear pin interface element) to simulate the soil-structure interaction. Bedding interface elements were used to capture the shear sliding of the soil on the low-interface friction plane while shear pin interface elements were used to model the shear bonding of the soil around the pins. A failure analysis was performed by means of the gravity loading method. The results of the 3D FEA with the numerical models were compared to those with the physical models for all cases. The effects of the number of shear pins, the shear pin locations, the different shear pin arrangements, the thickness and the width of the soil block and the associated failure mechanisms were discussed.