• Title/Summary/Keyword: Composite Noise

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A Study on Multiple Filter for Mixed Noise Removal (복합잡음 제거를 위한 다중 필터에 관한 연구)

  • Kwon, Se-Ik;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.11
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    • pp.2029-2036
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    • 2017
  • Currently, the demand for multimedia services is increasing with the rapid development of the digital age. Image data is corrupted by various noises and typical noise is mainly AWGN, salt and pepper noise and the complex noise that these two noises are mixed. Therefore, in this paper, the noise is processed by classifying AWGN and salt and pepper noise through noise judgment. In the case of AWGN, the outputs of spatial weighted filter and pixel change weighted filter are composed and processed, and the composite weights are applied differently according to the standard deviation of the local mask. In the case of salt and pepper noise, cubic spline interpolation and local histogram weighted filters are composed and processed. This study suggested the multiple image restoration filter algorithm which is processed by applying different composite weights according to the salt and pepper noise density of the local mask.

Development of Lightweight Composite Sub-frame in Automotive Chassis Parts Considering Structure & NVH Performance (구조 및 NVH 성능을 고려한 복합재료 서브프레임 개발)

  • Han, Doo-Heun;Ha, Sung
    • Composites Research
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    • v.32 no.1
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    • pp.21-28
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    • 2019
  • Recently, according to environmental regulations, the automobile industry has been conducting various research on the use of composite materials to increase fuel efficiency. However, there has not been much research on lightweight chassis components. Therefore, in this research, the purpose of this study is to apply composite materials to the sub-frame of chassis components to achieve equivalent levels of stiffness, strength, NVH performance and 50% lightweight compared to the steel sub-frame. First, the Natural frequency of steel and composite specimens was compared to the damping characteristics of composite materials. Then, in this study, the Lay-up Sequence was derived to maximize the stiffness and strength of the sub-frame by applying composite materials. And this lay-up Sequence is proposed to avoid heat shrinkage due to curing during manufacturing. This process was designed based on a FEM structural analysis, and a Natural frequency and frequency response function graph was confirmed based on a modal analysis. The prototype type composite sub-frame was manufactured based on the design and the F.E.M analysis was verified through a modal experiment. Furthermore, it was fitted to the actual vehicle to verify the natural frequency and the indoor noise vibration response, including idling and road noise. This result was confirmed to be equivalent to the steel sub-frame. Finally, the composite sub-frame weight was confirmed to be about 50% of the steel sub-frame.

Stability Analysis of Composite Material Pipes Conveying Fluid (유체유동에 의한 복합재료 파이프의 안정성 해석)

  • 최재운;송오섭
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.8
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    • pp.314-321
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    • 2001
  • Static and oscillatory loss of stability of composite pipes conveying fluid is Investigated. The theory of than walled beams is applied and transverse shear. rotary inertia, primary and secondary warping effects are incorporated. The governing equations and the associated boundary conditions are derived through Hamilton's variational principle. The governing equations and the associated boundary conditions are transformed to an eigenvlaue problem which provides the Information about the dynamic characteristics of the system. Numerical analysis is performed by using extended Gelerkin method. Variation of critical velocity of fluid with fiber angles and mass patios of fluid to pipe Including fluid is investigated.

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Characterization of a Misaligned Supercritical Shaft of Flexible Matrix Composite (축어긋남이 있는 유연복합재 고속구동축의 특성 분석)

  • 홍을표;신응수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.1
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    • pp.32-39
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    • 2004
  • This research is to investigate the performance of a flexible matrix composite driveshaft with respect to shaft design parameters such as the number of layers, ply orientations, and material properties. A finite element formulation is utilized to estimate the allowable misalignment under given driving torque, the maximum temperature at steady states, and external damping for ensuring whirling stability under supercritical speed. Results indicate that the system performance can be greatly affected by the shaft laminate parameters, especially the ply orientations. Several sets of shaft parameters that will provide satisfactory overall system performance are derived.

Vibration Control of Laminated Composite Beams Using Active Constrained Layer Damping Treatment (능동구속감쇠 기법을 이용한 복합적층보의 진동 제어)

  • 강영규;최승복
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.7
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    • pp.261-266
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    • 2001
  • The flexural vibration of laminated composite beams with active and passive constrained layer damping has been investigated to design a structure with maximum possible damping capacity. The equations of motion are derived fro flexural vibrations of symmetrical,. multi-layer laminated beams. The damping ratio and model damping of the first bending mode are calculated by means of iterative complex eigensolution method. The direct negative velocity feedback control is used for the active constrained layer damping. It is shown that the flexible laminated beam is more effective in the vibration control for both active and passive constrained layer damping. and this paper addresses a design strategy of laminated composite under flexural vibrations with constrained layer damping.

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Vibration Suppression of Hull Structure Using MFC Actuators (MFC 작동기를 이용한 Hull 구조물의 진동 저감)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.7 s.124
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    • pp.587-595
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    • 2007
  • Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC(macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

Vibration Suppression of Hull Structure Using MFC Actuators (MFC 작동기를 이용한 Hull 구조물의 진동 저감)

  • Sohn, Jung-Woo;Kim, Heung-Soo;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.1119-1124
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    • 2007
  • Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC (macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

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A Study on Performance Evaluation of On-board Electric Device of TTX(Tilting Train Express) (틸팅열차(TTX)의 정장품 성능평가 연구)

  • Han, Seong-Ho;Lee, Su-Gil;Seo, Sung-Il
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.239-242
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    • 2005
  • This paper introduced an approach of improvement of performance of Electric device for EMU type Train like as TTX. The electric equipments are characterized by insulation, Noise, cooling system etc. and Their weight arc decided by these factors. There are two kinds of power source in EMU train. First, DC voltage source, 1500 volt, 750 volt is used for subway system. Second, AC power source 25000 volt is applied to high speed train and existing main lines. Composite material has the protection of inrush current and high frequency noise. We can use this material to minimize weight of train. Additionally we can get energy saving when operator service TTX.

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The Stability of Composite Pipes Conveying Fluid (유체유동에 의한 복합재료 파이프의 안정성 연구)

  • 최재운;송오섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.904-910
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    • 2001
  • Static and oscillatory loss of stability of composite pipes conveying fluid is investigated. The theory of thin walled beams is applied and transverse shear, rotary inertia, primary and secondary warping effects are incorporated. The governing equations and the associated boundary conditions are derived through Hamilton's variational principle. The governing equations and the associated boundary conditions are transferred to eigenvalues problem which provides the information about the dynamic characteristics of the system. Numerical analysis is performed by using extended Gelerkin method. Critical velocity of fluid is investigated by increasing fiber angle and mass ratio of fluid to pipe including fluid.

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Hybrid vibration control of smart laminated composite beams using piezoelectric and viscoelastic material (압전재료와 점탄성 재료를 이용한 지능 적층보의 하이브리드 진동 제어)

  • 강영규;김재환;최승복
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.133-137
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    • 2001
  • Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained-layer damping have been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method, This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

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