• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.824-829
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• 2002

Since many reciprocating and rotating components are attached to jet loom structure. it is exposed to a more vibration and moise problems than the other textile machinery. Thus the design of the jet loom frame is very important to characterize the dynamic response. In this study, a finite element model of jet loom main frame was developed to investigate the dynamic characteristics of jet loom. Two different finite element models of different main frames were constructed and these models were validated by the experimental results. Dynamic characteristics such natural frequencies and mode shapes were in good agreement between the finite element analysis and experimental results within 10% error range. It is expected that the result from this study can be used as the basic information of jet loom dynamic analysis and be extended for further analysis of forced response case.

• 한국컴퓨터산업학회논문지
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• 제7권4호
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• pp.427-436
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• 2006

운동하는 물체의 동특성 해석을 위한 상태 공간 모델 방식이 컴퓨터에 의한 미분방정식 해석의 수학적인 도구로서 도입되었다. 시스템 표현이 간단한 행렬 연산 형태로 이루어지므로 선형 및 비선형, 시변 및 시불변 시스템과 단변수 및 다변수 시스템 등에 대하여 통일된 방식의 모델이 사용가능하다. 그리고 이러한 상태 공간 모델을 해석하기위해서는 복잡한 벡터 연산을 하여야 하지만 패킷 소프트웨어의 특정함수를 사용하여 쉽게 해석할 수가 있다. 그러나 최근에는 상용 프로그램의 발전에 따라 동특성 해석을 위한 상태 공간 모델을 대화형 도형 처리를 하여 매우 간단하게 동특성을 시뮬레이션 할 수 있는 방법이 제공되고 있다. 본 논문은 운동하는 물체의 동특성 해석을 하는 데 교육용으로 활용할 수 있는 시뮬레이터를 개발하는 목적으로 항공기의 세로 동특성 해석을 위한 시뮬레이션을 수행하고자 하였으며 항공기 세로 안정성에 대한 과도응답 특성을 해석하는 시뮬레이터를 설계하였다.

• 소성∙가공
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• 제9권3호
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• pp.293-303
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• 2000

Recent developments of Fe technology make it possible to apply CAD/CAE/CAM techniques successfully to the stamping die design among the automotive parts industries. Those successful applications are greatly attributable to the development of commercial S/W. Up to now most commercial S/W for the analysis of sheet metal forming is based on the dynamic explicit algorithm. The main characteristics of dynamic explicit algorithm is that there is no convergence problem if the time increment is taken less than the stability limit. The stability of the analysis is guaranteed in the commercial code, since the adequate time increment is computed from the so called "Courant Condition". However excess computing time is often pointed out in the dynamic explicit analysis according to the characteristics of process parameters taken. In the study, various parameters that may affect the stability and the method how to improve computational efficiency of analysis have been investigated.estigated.

• 유통과학연구
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• 제22권1호
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• pp.61-67
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• 2024

Purpose: The study has identified factors affecting dynamic capabilities and the distribution of competitive advantage under the impact of dynamic capabilities of Vietnamese fintech businesses. Research design, data, and methods: The method used in this study is a survey analysis of 120 Vietnamese fintech businesses to test the hypothesized relationships of the research model as well as evaluate its effectiveness. The study uses the Cronbach alpha analysis, factor analyses, and structural equation modeling to assess the research's measurement and structural models. Results: Research results show that 3 critical success factors: "Capacity to develop financial service ideas," "Ability to develop a platform," and "Business capacity" have a positive impact on "Dynamic capabilities." In addition, the study also evaluates the effect of "dynamic capabilities" on the "competitive advantage" of fintech businesses. Conclusion: Theoretically, this result contributes to discovering new, specific factors affecting the dynamic capabilities of fintech businesses. In practice, the research results are empirical evidence of the distribution of competitive advantages of Vietnamese Fintech businesses and their impact on dynamic capabilities.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.891-895
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• 1996

Performance and efficiency of hybrid (hydraulic-mechanical) pick-up device of deep sea manganese nodules collector are very sensitive to altitude and altitude of pick-up head relative to undulating seafloor. For this reason, motion control of pick-up head relative to the changing deep sea topography and other disturbances is of particular importance in design of pick-up device. The concept of design axiom is applied to a pick-up device of hybrid type. Kinematic analysis conducted in absolute Cartesian coordinates gives position, velocity, and acceleration of the hydraulic cylinders which enable the pick-up head to keep the preset optimal distance from seafloor. Inverse dynamic analysis provides the driving forces of hydraulic cylinders and the reaction forces at each joint. Design sensitivity analysis is performed in order to investigate the effects of possible design variables on the change of the maximum strokes of hydraulic cylinders. The direct differentiation method is used to obtain the design sensitivity coefficients.

• 항공우주시스템공학회지
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• 제6권4호
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• pp.29-33
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• 2012

This paper is focusing on the difference from experiment result and method through dynamic loaded from impact analysis about inertia measure unit of high speed projectile. At Inertia measure unit dynamic load is applied when the high speed projectile is operated by impact to inside. it is necessary to design inertia measure unit enduring from external effect with operating environment. Investigation of material deformation with high strain speed is performed for military purpose, and still concerned to many scientist. From this study, this paper will prove of impact analysis result through comparing with experiment result and method when applied dynamic load.

• 한국전산유체공학회지
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• 제19권4호
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• pp.37-44
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• 2014

A detailed satellite panel thermal model composed of more than thousands nodes can not be directly integrated into a spacecraft thermal model due to its node size and the limitation of commercial satellite thermal analysis programs. For the integration of the panel into the satellite thermal model, a reduced thermal model having proper accuracy is required. A thermal model reduction method was developed and validated by using a geostationary satellite panel. The temperature differences of main components between the detailed and the reduced thermal model were less than $1^{\circ}C$ in steady state analysis. Also, the dynamic responses of the detailed and the reduced thermal model show very similar trends. Thus, the developed reduction method can be applicable to actual satellite thermal design and analysis with resonable accuracy and convenience.

• 한국정밀공학회지
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• 제14권1호
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• pp.90-100
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• 1997

Sppur gear trains are used widely in high precision machines because gear trains have an advantage of exact transmission of angular velocity. Especially, gear trains are used in high quali8ty photocopying and photography OA machines. In general, gears have errors in manufacturing and assembling process and the errors are limited by tolerances. As the result, the tolerances cause the performance error. Therfore, it is important to predict transmission error caused by the tolerances for the tolerance design. Earlier tolerance design methods use mainly experimental and geometrical techniques. In this paper, a method for gear train analysis with tolerance is proposed. Because the method uses dynamic contacts, it is possible to consider irregularities and assemble errors of gears. In addition, the method can predit dynamic loads on the teeth of gears.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.819-828
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• 2002

An analytical method is presented for evaluation of the steady state periodic behavior of nonlinear systems. This method is based on the substructure synthesis formulation and a MS (multiple scales) procedure, which is applied to the analysis of nonlinear responses. The proposed procedure reduces the size of large degrees-of-freedom problem in solving nonlinear equations. Feasibility and advantages of the proposed method are illustrated with the nonlinear rotating machine system as an example of large mechanical structure systems. In addition, its efficiency for nonlinear response prediction will be shown by comparison of other conventional methods.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.111-135
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• 2015

Bridge behavior under passing traffic loads has been studied for the past 50 years. This paper presents how to model congestion on bridges and how the maximum dynamic stress of bridges change during the passing of moving vehicles. Most current research is based on mid-span dynamic effects due to traffic load and most bridge codes define a factor called the dynamic load allowance (DLA), which is applied to the maximum static moment under static loading. This paper presents an algorithm to solve the governing equation of the bridge as well as the equations of motions of two real European trucks with different speeds, simultaneously. It will be shown, considering congestion in eight case studies, the maximum dynamic stress and how far from the mid-span it occurs during the passing of one or two trucks with different speeds. The congestion effect on the maximum dynamic stress of bridges can make a significant difference in the magnitude. By finite difference method, it will be shown that where vehicle speeds are considerably higher, for example in the case of railway bridges which have more than one railway line or in the case of multiple lane highway bridges where congestion is probable, current designing codes may predict dynamic stresses lower than actual stresses; therefore, the consequences of a full length analysis must be used to design safe bridges.