• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.994-995
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• 2014

Supporting stiffness of seats is an important component affecting dynamic characteristics cognized by a passenger. To analyze dynamic characteristic of a seat for vehicles operating on various road conditions, the seat vibration from road irregularity should be understood and compared. In this study, the seat is analyzed as distributed supporting system. The dynamic stiffness is measured using masses. The characteristic of the seats is analyzed by measuring distributed dynamic stiffness. The distributed dynamic stiffness of the seat is estimated on various locations and the effects of each component such as spatial distribution, compression level and vibration amplitude are analyzed. The influence of seat cover, elastic support and flexible polyurethane foam on the measured stiffness was analyzed.

• 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.

• 문화기술의 융합
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• 제6권3호
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• pp.443-448
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• 2020

본 연구에서는 영종대교를 구성하고 있는 교량형식(트러스교, 현수교)별 열차종류(AREX, AREX Express, KTX, KTX-Sancheon) 및 열차속도가 강직결 궤도구조의 동적거동에 미치는 영향을 분석하고자 현장측정을 수행하였다. 현장측정결과를 바탕으로 궤도충격계수 및 열차주행안정성(탈선계수, 윤중감소율, 레일두부횡변위)을 국내, 외 관련기준 및 법규와의 비교하여 영종대교 교량상 강직결 궤도구조의 동적거동에 영향을 미치는 열차하중 및 속도의 효과를 분석하였다. 연구결과, 영종대교 교량형식별 궤도의 동적거동의 차이는 뚜렷하지 않으나 열차하중의 크기에 보다 직접적인 영향을 받는 것으로 분석되었다. 따라서 향후 열차속도 증가에 따른 궤도충격계수의 증가와 이에 따른 궤도부담력의 증가수준을 감안한 영종대교 강직결 궤도구조의 보강방안 수립이 필요할 것으로 판단된다.

• 한국음향학회지
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• 제37권5호
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• pp.338-342
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• 2018

상하층 간 공동주택의 바닥충격음 문제를 해결하기 위해 국토교통부에서는 바닥충격음 레벨에 영향을 미치는 완충재에 대한 물성 기준도 함께 고시하고 있다. 완충재에 대한 물성 기준중 가열전후 동탄성계수, 손실계수는 특히 바닥충격음과 가장 연관되어 있다. 따라서 본 연구에서는 기준에서 명시하고 있는 $70^{\circ}C$의 온도 조건을 기준으로 $10^{\circ}C$씩 증가시키고 $10^{\circ}C$씩 저감시켜 온도변화에 따른 동탄성계수 및 손실계수에 대하여 변화율을 검토하였다. 총 8가지 종류의 시료에 대하여 동탄성계수 및 손실계수 측정 방법은 펄스 가진법으로 수행되었으며 결과 산출방법은 감쇠 진동 파형을 이용한 시계열 해석법으로 산출하였다.

• 한국지반공학회지:지반
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• 제6권3호
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• pp.13-30
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• 1990

본 연구에서는 깊은 기초의 내진설계에 적용하기 위해, 지진하중에 의한 말뚝기초의 응답을 산출하여 비교, 검토하였다. 본 연구에서 사용된 해석 방법은 Subgrade Reaction Theory 및 탄성해석법과 같은 유사정적 해석방법, Prakash및 Gazetas가 각각 제안한 동적 해석방법이며, 예제해석을 통해 말뚝의 최대 상대변위 및 최대 휨모멘트를 위의 각 방법을 이용해서 산출하였고, 그 결과를 각각 비교하였다. 또한 말뚝의 군효과를 근사적으로 고려하여 Novak에 의해 수행된 실험 결과와 비교하였다. 해석결과를 분석해 볼 때 Kaynia와 Kausel이 제안한 동적 Group Interaction Factor Approach 에 의한 땅법 및 Gazetas가 제안한 방법의 최대 상대변위는 실측치와 부합하게 산정되었으며, Prakash 가 제안한 방법과 정적 Group Interaction Factor Approach에 의한 변위 및 휨모멘트는 과대평가되었다. 그러므로, 말뚝의 내진설계시에 동적 Group Interaction Factor Approach와 결합한 유사정적해석 을 사용하고 Gazetas가 제안한 동적방법에 의해 이를 검토하는 것이 바람직하다.

• 대한원격탐사학회지
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• 제26권4호
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• pp.395-401
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• 2010

영상 강조 기법은 영상의 낮은 명암 대비(contrast)를 노이즈나 블러링(blurring)의 제거, 명암 대비의 증가, 세밀함의 확장 등을 통해 시각적으로 향상시키는 작업을 말한다. 본 논문에서는 기존에 제안되어 온 여러 영상 강조 기법들의 장점을 기반으로 한 Adaptive dynamic range linear stretching(ADRLS) 영상 강조 기법을 제안한다. ADRLS 기법은 입력 영상의 히스토그램 분할과 동시에 adaptive scale factor를 적용하여 다수의 서브 히스토그램을 생성하는 것에 초점을 맞추고 있으며, 생성된 서브 히스토그램은 최종적으로 선형 강조(Linear Stretching, LS) 기법이 적용되어 영상 강조를 수행하게 된다. 제안된 기법의 성능을 검증하기 위해 기존의 히스토그램 선형 강조 기법, 히스토그램 평활화(Histogram Equalization, HE) 기법과 비교 평가하였으며, 그 결과 기존의 기법들에 비해 영상의 과도한 밝기 변화를 억제함으로써 영상의 시각적인 특성을 유지하고, 입력 영상이 갖고 있는 히스토그램의 특성을 보존하는 효과를 보였다.

• Coupled systems mechanics
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• 제9권4호
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• pp.311-323
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• 2020

This paper deals with the effect of the mode shapes on the dynamic response of a multi-storey frame subjected to moving train loads which are modelled as loads of constant intervals with constant velocity using the finite element method. The multi-storey frame is modelled as a number of Bernoulli-Euler beam elements. First, the first few modes of the multi-storey frame are determined. Then, the effects of force span length to beam length ratio and velocity on dynamic magnification factor (DMF) are evaluated via 3D velocity-force span length to beam length ratio-DMF graphics and its 2D projections. By using 3D and 2D graphics, the directions of critical speeds that force the structure under resonance conditions are determined. Last, the mode shapes related to these directions are determined by the time history and frequency response graphs. This study has been limited by the vibration of the frame in the vertical direction.

• 드라이브 ㆍ 컨트롤
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• 제17권1호
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• pp.44-50
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• 2020

For the requirement of accurate tracking control and the safety of physical human-robot interaction, torque control is basically desirable for humanoid robots. Because of the complexity of humanoid robot dynamics, the TDC (time-delay control) is practical because it does not require a dynamic model. However, there occurs a considerable error due to discontinuous non-linearities. To solve this problem, the TDC-FLC (fuzzy logic compensator) is applied to humanoid robots. The applied controller contains three factors: a TDE (time-delay estimation) factor, a desired error dynamic factor, and FLC to suppress the TDE error. The TDC-FLC is easy to execute because it does not require complicated humanoid dynamic calculations and the heuristic fuzzy control rules are intuitive. TDC-FLC is implemented on the whole body of a humanoid, not on biped legs even though it is performed by a virtual humanoid robot. The simulation results show the validity of the TDC-FLC for humanoid robots.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.721-724
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• 2005

With the advantages of large vibration energy dissipation of structures, the granular materials are used as vibration and acoustic treatments. In this case of vibro acoustic controls, a finite dynamic strength of the solid component (frame) is an important design factor. The dynamic stiffness of hollow cylindrical beams containing porous and granular materials as damping treatment was measured. Using the Rayleigh-Ritz method, the effects of damping materials on the dynamic characteristics of beams were investigated. The results suggested that the acoustic structure Interaction between the frame and the structure enhances the dissipation of the vibration energy significantly. The same methods were applied also to vibration control of sandwich panels. By filling the cavities of honeycomb cores using unconsolidated granular materials, its sound transmission toss was improved significantly.

• 한국안전학회지
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• 제31권5호
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• pp.89-94
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• 2016

The objective of this study was to estimate the dynamic behavior of a personal rapid transit(PRT) track system using a rail of rectangular tube section and a rail joint of sliding type, and to compare the results with the normal rail and rail joint of a PRT track system by performing field measurements using actual vehicles running along the service lines. The measured vertical displacement of rail and sleeper, and vertical acceleration of rail for the normal rail and rail joint section were found to be similar, and the rail joint of sliding type satisfied the design specifications of the track impact factor for a conventional railway track. The experimental results showed that the overall dynamic response of the rail joint were found to be similar to or less than that of the normal rail, therefore the rail joint of sliding type for PRT track system was sufficient to ensure a stability and safety of PRT track system.