• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 2부
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• pp.233-238
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• 2008

엠비언트 미디어(Ambient Media or Ambient Display, Wisneski et al 1998)는 우리 주변의 일상적인 사물이나 환경의 동적인 변화를 통해 정보를 표현하는 새롭게 등장한 동적인 디자인 대상중 하나이다. 사용자가 집중한 상황만을 다루는 기존의 GUI기반 미디어와 달리, 엠비언트 미디어는 사용자가 주목하지 않는 상황에서도 주변적으로 정보를 인식할 수 있도록 전달한다. 엠비언트 미디어의 디자인을 위해서는 물리적 공간에서 동적인 속성을 가지는 디자인 구성 요소들에 대한 이해를 바탕으로 이를 주변적으로 전달할 수 있는 활용 방식에 대한 연구가 필요하다. 본 연구의 목표는 디자인 대상의 변화로 새롭게 등장한 동적인 디자인 요소를 파악하고, 이를 엠비언트 미디어의 특성에 적합하게 적용하기 위한 디자인 방법을 연구하는 것이다. 다양한 동적인 관련 분야 연구와 엠비언트 미디어의 사례 조사를 통해 동적인 디자인 요소를 탐색하여 도출하였다. 그 결과, 빠르기, 연속성, 강도 리듬의 4가지 동적인 디자인 요소를 제안하였다. 또한 심리학 분야 및 엠비언트 미디어 분야의 주변적인 인식 관련 연구를 통해 사용자가 집중하지 않고 주변적으로 인식될 때의 동적인 디자인 요소가 가지는 특정을 파악하였다. 이를 기반으로 새로운 엠비언트 미디어 사례를 개발하여 주변적으로 정보를 인식할 수 있도록 엠비언트 미디어를 디자인하기 위해 동적인 디자인 요소를 활용하는 방안을 탐색하였다. 본 연구를 통해, 주변적인 정보 전달을 위해 필요에 따라 정보를 주변적으로 혹은 중심적으로 표현하는 엠비언트 미디어 디자인에 기여할 수 있을 것으로 기대된다. 동적인 디자인 요소에 대한 규명과 그 특성에 대한 이해는 엠비언트 미디어뿐만 이니라 다양한 시간에 따른 동적인 표현을 위한 디자인 분야에 도움을 줄 수 있으리라 생각된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.590-595
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• 2001

To improve the modeling accuracy for the finite element method, this paper proposes a method to make a combined use of finite elements and exact dynamic elements. Exact interpolation functions for a Timoshenko beam element are derived and compared with interpolation functions of the finite element method (FEM). The exact interpolation functions are tested with the Laplace variable varied. The exact interpolation functions are used to gain more accurate mode shape functions for the finite element method. This paper also presents a combined use of finite elements and exact dynamic elements in design problems. A Timoshenko frame with tapered sections is tested to demonstrate the design procedure with the proposed method.

• 한국소음진동공학회논문집
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• 제12권2호
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• pp.141-149
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• 2002

Although the finite element method has become an indispensible tool for the dynamic analysis of structures, difficulty remains to quantify the errors associated with discretization. To improve the modeling accuracy, this paper proposes a method to make a combined use of finite elements and exact dynamic elements. Exact interpolation functions for the Timoshenko beam element are derived using the exact dynamic element modeling (EDEM) and compared with interpolation functions of the finite element method (FEM). The exact interpolation functions are tested with the Laplace variable varied. A combined use of finite element method and exact interpolation functions is presented to gain more accurate mode shape functions. This paper also presents a combined use of finite elements and exact dynamic elements in design/reanalysis problems. Timoshenko flames with tapered sections are tested to demonstrate the design procedure with the proposed method. The numerical study shows that the combined use of finite element model and exact dynamic element model is very useful.

• Steel and Composite Structures
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• 제45권5호
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• pp.697-713
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• 2022

In the context of the finite elements method, the dynamic behavior of porous functionally graded double wishbone vehicle suspension structural system incorporating joints flexibility constraints under road bump excitation is studied and analyzed. The functionally graded material properties distribution through the thickness direction is simulated by the power law including the porosity effect. To explore the porosity effects, both classical and adopted porosity models are considered based on even porosity distribution pattern. The dynamic equations of motion are derived based on the Hamiltonian principle. Closed forms of the inertia and material stiffness components are derived. Based on the plane frame isoparametric Timoshenko beam element, the dynamic finite elements equations are developed incorporating joint flexibilities constraints. The Newmark's implicit direct integration methodology is utilized to obtain the transient vibration time response under road bump excitation. The presented procedure is validated by comparing the computational model results with the available numerical solutions and an excellent agreement is observed. Obtained results show that the decrease of porosity percentage and material graduation tends to decrease the deflection as well as the resulting stresses of the control arms thus improving the dynamic performance and increasing the service lifetime of the control arms.

• 소음진동
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• 제10권3호
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• pp.437-443
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• 2000

The optimal design problem for increasing dynamic stiffness using hybrid model which composed of original detailed BIW(body in white) and impinged beam elements is investigated. Using the characteristics of the beam elements and design sensitivity analysis this approach utilizes an optimization technique to determine the optimal section properties of beam elements. The constraint is to increase the first natural frequency by five percent compared with original one. The results show that the first torsion and bending natural frequencies are increased by five percent using hybrid model and optimization. These results indicate that this optimization method can be employed to enhance the dynamic stiffness of vehicle body structure in design concept stage.

• 한국기계가공학회지
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• 제9권5호
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• pp.76-82
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• 2010

In this study, we carried out to evaluate the shock-proof of a large scale motor for the naval vessel using dynamic design analysis method (DDAM) and full transient dynamic analysis. Analytical models for main assemblies (motor frame, rotor and stator assembly) were consisted of the tetrahedral solid elements and the equipments which installed in the upper side of the motor were substituted the mass elements. And we also modelled resilient mounts of a motor using the beam elements with appropriate directional stiffness. The DDAM was conducted according to NRL memorandum report 1396 and the full transient dynamic analysis was performed applying directional triple half triangle shock wave to the motor using ANSYS 12. As a result, we could compare of the results according to each analytic method and find the motor to satisfy the design criteria of the maximum stress and deformation.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2004년도 추계학술발표대회 논문집
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• pp.92-97
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• 2004

This purpose of this study was about the analysis on the dynamic expression of geometric manipulation in interior composition elements. The paradigm of contemporary times became different from paradigm of modern times. The change of paradigm is caused by the side effect of paradigm of pre-times. In the contemporary architectural condition, architecture have a tendency to plural characteristics. This study investigates systemically ‘the DYNAMISM’ as a part of contemporary interior space's feature, based on geometric manipulation in interior composition elements. First of all, the dynamic characteristics of architectural space. The second, relationship between the architecture and geometric manipulation.

• 대한건축학회논문집:구조계
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• 제36권3호
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• pp.121-128
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• 2020

In this paper, the ASCE 7 equivalent static approach for seismic design of non-structural elements is critically evaluated based on the measured floor acceleration data, theory of structural dynamics, and linear/nonlinear dynamic analysis of three-dimensional building models. The analysis of this study on the up-to-date database of the instrumented buildings in California clearly reveals that the measured database does not well corroborate the magnitude and the profile of the floor acceleration as proposed by ASCE 7. The basic flaws in the equivalent static approach are illustrated using elementary structural dynamics. Based on the linear and nonlinear dynamic analyses of three-dimensional case study buildings, it is shown that the magnitude and distribution of the PFA (peak floor acceleration) can significantly be affected by the supporting structural characteristics such as fundamental period, higher modes, structural nonlinearity, and torsional irregularity. In general, the equivalent static approach yields more conservative acceleration demand as building period becomes longer, and the PFA distribution in long-period buildings tend to become constant along the building height due to the higher mode effect. Structural nonlinearity was generally shown to reduce floor acceleration because of its period-lengthening effect. Torsional floor amplification as high as 250% was observed in the building model of significant torsional irregularity, indicating the need for inclusion of the torsional amplification to the equivalent static approach when building torsion is severe. All these results lead to the conclusion that, if permitted, dynamic methods which can account for supporting structural characteristics, should be preferred for rational seismic design of non-structural elements.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.309-317
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• 2007

In this study, we conducted a vibration fatigue analysis of the lower control arm in a vehicle suspension system. The vehicle was driven during the tests so that the dynamic effects could be taken into account. The dynamic load of the frequency domain was superimposed on the frequency response analysis. We performed a virtual proving ground test using multi-body dynamics, along with a finite element analysis and fatigue life predictions. Shape optimization was also considered using the design of the experimental approach, and a response surface analysis was performed to improve the durability performance of the lower control arm. We identified the elements that had the most influence on the optimal shape of the finite element model and analyzed the sensitivity of those elements. Then the optimal points that minimized the amount of damage to the areas of interest were determined through a response surface analysis. The results suggested that the fatigue life of the model increased as its mass was not increased excessively, and demonstrated that these design procedures yielded an appropriate optimized lower control arm model.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.35-38
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• 2007

액체로켓엔진(Liquid Rocket Engine) 의 천이성능 예측을 위해 선행연구 되었던 LRE 시스템 모듈화 프로그램의 결과를 살펴보고, 일본의 로켓엔진 동적 해석 프로그램(Rocket Engine Dynamic Simulator)의 엔진 시스템 동적 해석 방법과 모델링에 대해 고찰하였다. LRE 시스템 모듈화 프로그램에서는 각 구성품에 대한 설계 인자를 수학적으로 모델링하였고 구성품 간의 유량과 압력을 매칭시켜 통합하여, 로켓엔진 시스템의 요구조건을 만족하는 각 구성품에 대한 주요 설계 파라미터를 도출하는 과정에 관하여 논의하였다. 로켓엔진 시스템을 유한한 배관요소들의 연결로 모델링하고, 시간의 함수로 표현되는 보존방정식을 적용하여 터보펌프, 밸브, 오리피스，추력실 등 유체기기의 작동 특성을 모사하는 동특성 설계 과정에 관하여 고찰한다.