• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.199-202
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• 2003

The dynamic characteristics of composite tool bars depend on the clamping conditions such as clamping force, stiffness and surface characteristics of clamping parts as well as the basic structures. Therefore, in this work, the effects of clamping part conditions on the dynamic characteristics of cantilever type composite machine tool structures with clamped joint were investigated because the cantilever type machine tool structures are ideal cases for composite application to increase the natural frequency and damping of structures. New design of the clamping part was developed in order to improve shear properties of the clamping part and dynamic characteristics of composite tool bars. From FE analysis and Impulse response tests, dynamic characteristics were obtained with respect to the clamping part conditions of the new design.

• Smart Structures and Systems
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• 제20권5호
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• pp.583-593
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• 2017

This research deals with the nonlocal temperature-dependent dynamic buckling analysis of embedded sandwich micro plates reinforced by functionally graded carbon nanotubes (FG-CNTs). The material properties of structure are assumed viscoelastic based on Kelvin-Voigt model. The effective material properties of structure are considered based on mixture rule. The elastic medium is simulated by orthotropic visco-Pasternak medium. The motion equations are derived applying Sinusoidal shear deformation theory (SSDT) in which the size effects are considered using Eringen's nonlocal theory. The differential quadrature (DQ) method in conjunction with the Bolotin's methods is applied for calculating resonance frequency and dynamic instability region (DIR) of structure. The effects of different parameters such as volume percent of CNTs, distribution type of CNTs, temperature, nonlocal parameter and structural damping on the dynamic instability of visco-system are shown. The results are compared with other published works in the literature. Results indicate that the CNTs have an important role in dynamic stability of structure and FGX distribution type is the better choice.

• 전산구조공학
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• 제6권2호
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• pp.87-93
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• 1993

최근 구조물의 동적해석에서 구조물-지반 상호작용이 구조물의 동적거동에 미치는 영향이 매우 중요하다는 것이 인식되어지고 있다. 이 논문에서는 관성력에 의한 구조물-지반 상호작용이 건물의 동적거동에 미치는 영향을 살펴보기 위하여 유한요소기법을 이용하여 이론적인 연구와 시험적 조사 (Experimental Investigation)연구를 수행하였다. 이론적 연구는 균질한 지반위에 기초가 약간 묻혀있는 낮고 강성이 강한 건물과 높고 가느다란 건물 두개에 대하여 수행하였으며, 시험적 조사연구는 1985년 멕시코 대지진을 겪은 말뚝기초위에 세워진 두개의 건물에 대해 수행하였다. 이 연구 결과를 살펴보면 구조물-지반 상호작용이 구조물에 미치는 주된 영향은 고유주파수 감소와 유효감쇄비 증가인데, 그 영향이 구조물 동적거동에 심각한 영향을 미치는 경우가 있기 때문에 구조물-지반 상호작용 영향을 구조물 동적해석시 필히 고려해야 한다는 것이다.

• 감성과학
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• 제10권1호
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• pp.113-125
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• 2007

본 연구에서는 동영상 자극과 정지 영상 자극을 사용하여 얼굴 표정의 영역(얼굴 전체/눈 영역/입 영역)에 따른 정서 상태 전달 효과를 알아보고자 하였다. 동영상 자극은 7초 동안 제시되었으며, 실험 1에서는 12개의 기본 정서에 대한 얼굴 표정 제시 유형과 제시 영역에 따른 정서 인식 효과를, 실험 2에서는 12개의 복합 정서에 대한 얼굴 표정 제시 유형과 제시 영역에 따른 정서 인식 효과를 살펴보았다. 실험 결과, 동영상 조건이 정지 영상 조건보다 더 높은 정서 인식 효과를 보였으며, 입 영역과 비교하였을 때 동영상에서의 눈 영역이 정지 영상 보다 더 큰 효과를 보여 눈의 움직임이 정서 인식에 중요할 것임을 시사하였다. 이는 기본 정서 뿐 아니라 복합 정서에서도 어느 정도 관찰될 수 있는 결과였다. 그럼에도 불구하고 정서의 종류에 따라 동영상의 효과가 달라질 수 있기 때문에 개별 정서별 분석이 필요하며, 또한, 얼굴의 특정 영역에 따라서도 상대적으로 잘 나타나는 정서 특성이 다를 수 있음을 사사해 준다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1174-1179
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• 2004

Field tests were conducted to investigate effects of a rail joint on the dynamic behavior of railway bridge. A four-span simpled supported plate girder bridge which has a rail joint on the third span was selected for tests. At the operating train loading, the induced vibration of the first and third span has been examined. The dynamic magnification ratio was used for quantitative analysis of impact effects caused by rail joint. The result of tests show that dynamic behavior of railway bridge picked up considerably due to a rail joint.

• Wind and Structures
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• 제8권3호
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• pp.147-161
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• 2005

Two identical tall building models with square cross-sections are experimentally studied in a wind tunnel with high-frequency-force-balance (HFFB) technique to investigate the interference effects on wind loads and dynamic responses of the interfered building. Another wind tunnel test, in which the interfered model is an aeroelastic one, is also carried out to further study the interference effects. The results from the two kinds of tests are compared with each other. Then the influences of turbulence in oncoming wind on dynamic interference factors are analyzed. At last the artificial neural networks method is used to deal with the experimental data and the along-wind and across-wind dynamic interference factor $IF_{dx}$ & $IF_{dy}$ contour maps are obtained, which could be used as references for wind load codes of buildings.

• Structural Engineering and Mechanics
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• 제41권1호
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• pp.139-155
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• 2012

Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.

• 수산경영론집
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• 제41권2호
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• pp.107-133
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• 2010

As policy makers are often concerned about dynamic effects of demand behavior and its welfare analysis by quantity changes, the paper shows how dynamic price formation systems can be built up to analyze the effect of policy options to the markets dynamically. The paper develops dynamic model of price formation for fish from the intertemporal optimization of the consumer choice problem. While the resulting model has a similar form of the error correction types of dynamic price formation system, it provides the rational demand behavior contrary to the myopic behavior of error correction demand models. The paper also develops appropriate tools of dynamic welfare analysis in quantity space using only short-run demand estimates both theoretically and empirically as a first attempt in the literature of price formation and fisheries. The empirical results of Korean fish markets show that the dynamic model and the welfare measures are reasonably plausible. The methodology and theory of this research can be applied and extended to the commodity aggregation, dynamic demand estimation, and dynamic welfare effects of regulation in the similar framework. Thus, it is hoped that this will enhance its applications to the demand-side economics.

• The Journal of Asian Finance, Economics and Business
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• 제7권1호
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• pp.259-268
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• 2020

The purpose of this study is to examine the predictive effects of intuition, business analytic, networking capabilities on innovation performance. The data was collected using a cross-sectional quantitative survey. A total of 292 useable responses were collected from Thai Processed Food Exporters (TPFE). The findings also indicated that the hypothesized relationships between the independent and dependent variables fit the empirical data. Specifically, it is revealed that strategic intuition, business analytic capabilities, network-based capabilities and dynamic capabilities had a direct effect on dynamic strategy. They also had statistically significant direct and indirect effects on dynamic performance. Based on the results of the correlation test, the researchers developed a dynamic capability model for the development of the dynamic performance of the operators, which included concepts, principles, methods, tools and guidelines. Furthermore, the impacts of intuition, business analytic, networking capabilities on dynamic strategy are also examined in this study. It makes a considerable contribution to the existing literature on dynamic strategy of TPFE, particularly in regards to explaining the performance.

• 경제분석
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• 제17권4호
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• pp.30-51
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• 2011

무역자유화의 파급효과를 분석한 선행 연구의 대부분은 어떤 시점에 이루어진 무역자 유화가 해당연도 또는 그 다음연도와 같은 특정시점의 경제성과(economic performance)에만 영향을 미치는 것처럼 암묵적으로 가정하기 때문에 본질적으로 정태분석의 한계를 벗어나지 못한다. 이러한 선행연구와는 달리 본 연구는 무역자유화가 경제성과에 지속적으로 영향을 미칠 수 있는 동태적 실증분석모형을 설정하여 무역자유화의 누적효과(cumulative effects)를 분석한다. 또한 무역자유화의 파급효과에 대한 실증분석에서 제기되는 내생성(endogeneity)의 문제를 통제하기 위해 수준방정식과 차분방정식을 동시에 이용하는 동태적 패널 데이터 분석방법인 시스템 일반화적률법(system GMM)을 적용한다. 본 연구는 1988-2005년 기간의 한국 제조업을 대상으로 무역자유화의 정태 효과 및 동태적 누적효과를 추정하였는데, 무역자유화의 파급효과는 상당 기간 동안 지속되고, 동태적 누적효과는 정태효과에 비해 훨씬 더 크게 나타났다.