• Title/Summary/Keyword: impulsive mode

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Development of OCB mode with impulsive driving scheme for improving moving picture quality

  • Kim, J.L.;Lee, C.H.;Park, S.Y.;Yoo, S.W.;Oh, J.H.;Lee, S.H.;Chai, C.C.;Park, C.W.;Ban, B.S.;Ahn, S.H.;Hong, M.P.;Chung, K.H.;Lim, S.K.;Kim, K.H.;Souk, J.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1049-1052
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    • 2004
  • In general, contrary to the CRTs with impulsive emission, liquid crystal displays have motion artifacts such as blurring. ghost image, decrease of dynamic CR(contrast ratio), and stroboscopic motion due to hold type driving method. In this paper, to improve motion picture quality of LCDs. impulsive driving method of black data insertion was applied to the OCB mode which is well known for its fast LC response time and wide viewing angle properties. Subject evaluation was carried out with CRT, TN, SIPS(Super IPS). and impulsive driving OCB. Moving picture image quality near CRT was obtained in impulsive OCB driving mode

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Vibration Analysis of a Rotating Cantilever Beam Undergoing Impulsive Force Using Wavelet Transform (Wavelet Transform을 이용한 충격력을 받는 회전하는 외팔 보의 진동 특성 해석)

  • Park, Ho-Young;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.10
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    • pp.1024-1032
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    • 2008
  • The vibration characteristics of a rotating cantilever beam undergoing impulsive force are investigated using wavelet transformation. The transient response induced by the impulsive force and the rigid body motion of the beam are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. The vibration characteristics of the beam can be analyzed in time-frequency domain with the wavelet transform method. Therefore, the effects of the impulsive force on the transient vibration characteristics of the beam can be investigated more effectively.

Dynamic Analysis of a Cantilever Beam Undertaking Impulsive Force That Undergoes Rigid Body Motion (강체 운동을 고려한 충격을 받는 외팔 보의 동적 해석)

  • Lim, Hong-Seok;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.890-895
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    • 2005
  • This paper presents the dynamic analysis of a cantilever beam undertaking impulsive force that undergoes rigid body motion. The transient response of the beam induced by the impulsive force and the rigid body motion is calculated based on hybrid deformation variable modeling method by applying the Rayleigh-Ritz assumed mode method. The stiffness variation effect caused by the rigid body motion is considered in this modeling. The effects of the impulsive force position and the angular velocity on the transient responses of the beam are investigated through numerical studies.

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Vibration Analysis of a Rotating Cantilever Beam Undergoing Impulsive Force Using Wavelet Transform (Wavelet Transform을 이용한 충격력을 받는 회전하는 외팔 보의 진동 특성 해석)

  • Park, Ho-Young;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.400-406
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    • 2008
  • The vibration characteristics of a rotating cantilever beam undergoing impulsive force are investigated using wavelet transformation. The transient response induced by the impulsive force and the rigid body motion of the beam are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. The vibration characteristics of the beam can be analyzed in time-frequency domain with the wavelet transform method. Therefore, the effects of the impulsive force on the transient vibration characteristics of the beam can be investigated more effectively.

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ORBITAL MANEUVER USING TWO-STEP SLIDING MODE CONTROL (2단 슬라이딩 제어기법을 이용한 인공위성의 궤도조정)

  • 박종옥;이상욱;최규홍
    • Journal of Astronomy and Space Sciences
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    • v.15 no.1
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    • pp.235-244
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    • 1998
  • The solutions of orbital maneuver problem using the sliding mode control in the presence of the erath gravitational perturbations is obtained. Especially, the optimization of consuming fuel for maneuver is performed. The impulsive solution to Lambert's problem using the combined equation method to minimize total ${\Delta}V is used for the desired orbit and the maneuver times. Two-step sliding mode control method is introduced for satisfying the boundary conditions of finite-thrust rendezvous problem at the end of maneuver time. Using the new approach to the orbit maneuver problem, two-step sliding mode control, orbit maneuvers are processed. The solutions to a rendezvous using the optimal control are obtained, and they are compared to the results by two-step sliding control.According to the new approach for orbit maneuver, the thrust-coast-thrust type controller is obtained to make satellite to track desired Lambert's orbit, and the total ${\Delta}V$ required for maneuver is resonable in comparison with the impulsive solution to Lambert's problem. The final state variables, also are close to the boundary conditions at the end of maneuver times.

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Dynamic Analysis of an Impulsively Forced Rotating Cantilever Beam (충격력을 받는 회전하는 외팔 보의 동적 해석)

  • Lim, Hong-Seok;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.3 s.108
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    • pp.226-232
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    • 2006
  • This paper presents the dynamic analysis of an impulsively forced rotating cantilever beam with rigid body motion. The transient response induced by the impulsive force and the rigid body motion of the beam are calculated using hybrid deformation variable modeling with the Rayleigh-Ritz assumed mode methods. The stiffness variation effect due to the rigid body motion of the beam is considered in this study Also, the effects of the impulsive force position and the angular velocity on the transient responses of the beam are investigated through numerical works.

Study on the Dynamic Deformation Characteristics of a Cantilever Beam Undergoing Impulsive Force Using Wavelet Transformation (웨이블렛 변환을 이용한 충격력을 받는 외팔 보의 동적 변형 특성 연구)

  • Park, Ho-Young;Yoo, Hong-Hee
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.943-947
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    • 2008
  • Dynamic response characteristics of a beam undergoing impulsive force are investigated using the wavelet transform method in this study. When an impulse is applied to an arbitrary position of a beam, it will generate a structural deformation wave. The characteristics of the wave are changing in the domain of time and space. The maximum amplitude of each natural frequency mode and the time to reach the maximum amplitude are obtained in this study. The effects of the location of impulse on the variations of the dynamic characteristics is also investigated.

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Beat Maps of a Slightly Asymmetric Ring (미소 비대칭 링의 맥놀이 지도)

  • 박석균;박기영;서백수;김석현
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1169-1176
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    • 2002
  • Analytical model of beat response is derived on a slightly asymmetric ring and is veryfied by experiment. The asymmetric ring is a simplified model used to explain the beat property of a Korean bell. The asymmetric ring has mode pair having slight frequency difference in each radial mode. Each mode pair produces beat phenomenon by the interaction of the two close frequency components. Based on the analytical model, beat maps are first proposed and characteristics of beat on the circumference are detaily explained.

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Estimation of Dynamic Properties of Steel Liquid Storage Tank by Shaking Table Test (진동대 실험에 의한 강재 액체저장탱크의 동특성 분석)

  • Choi, Hyoung Suk;Park, Dong Uk;Kim, Sung Wan;Kim, Jae Min;Baek, Eun Rim
    • Journal of the Earthquake Engineering Society of Korea
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    • v.21 no.4
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    • pp.153-161
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    • 2017
  • Liquid storage tank is one of the major infrastructures and generally used to store gases, drinking and utilizing water, dangerous fluids, fire water and so on. According to the recent reports and experiences, the tank structures are damaged in many earthquakes due to their low energy dissipating capacity. Therefore, many researchers have been tried to know the dynamic properties of the tanks including liquids. However, vary limited experimental studies are carried out using relatively small tank models. In this study, a series of shaking table tests are performed with maximum 2 m cubic rectangular liquid storage tanks made of steel to measure the natural frequency and estimate damping coefficient of impulsive and convective mode of the tanks. Especially, the damping values under different shapes and excitation methods are estimated by logarithmic decrement method and half power band-pass method and compared with current design code and standards such as ASCE 7, Eurocode 8 and NZS. Test results show that the impulsive mode damping is around 2% which is proposed by general standards and codes but the impulsive mode damping is 0.13% average that is slightly lower than the code recommendation.