• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.571-581
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• 2010

This study analyzed rainfall-runoff characteristics by deriving multiple impulse responses. The concept of competing impulse responses was used for deriving multiple impulse responses. Based on this concept, each response function derived competes to be selected for simulating the runoff measured. This concept of competing linear impulse responses was applied to four basins, Jeongseon, Yeongwol, Youngchoon and Chungju Dam. One to three impulse responses have been derived and compared each other considering basin characteristics. First, in case of deriving one linear impulse response, the peak flow of the impulse response was found to be increased according to their study basins area. In case of deriving two linear impulse response, the peak flow of the first impulse response and the duration of the second impulse response were increased according to their basin size. The case of deriving three impulse response showed similar characteristics of deriving two impulse responses. However, the peak flow of third impulse response was very small and lasted quite long time. Summarizing these results considering the basin characteristics, the first impulse response seems to be related with the surface runoff, the second impulse with the surface runoff and interflow, and the third impulse response with the interflow and base flow.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.11a
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• pp.22-25
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• 2022

본 논문에서는 인공적인 가상 환경에서 사실적인 충격응답을 제공할 수 있는 방법을 모색하기 위한 첫 단계로서 실제 청취 공간에서 충격응답을 획득하고 장애물이 존재할 때 그 충격응답이 어떻게 변화하는지 살펴보기 위하여 충격응답 변화 실측에 대한 실험 결과를 제시한다. 실험은 일상적인 공간으로서 한국전자통신연구원의 회의실과 휴게실에서 수행하였으며, 실험 결과 장애물의 존재에 따라 그리고 청취 위치에 따라 주파수 영역에서 차이점이 발생하는 것을 확인할 수 있었다. 향후 흡음률 등 장애물에 대한 물리적 정보를 조사, 분석하고 보다 더 다양한 공간과 위치에서 장애물에 대한 충격응답의 변화로부터, MPEG-I Immersive Audio 등의 애플리케이션에서 사실적인 공간감을 제공하기 위한 인공적인 충격응답을 가공 방법을 제안할 수 있을 것으로 기대한다.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.75-84
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• 1996

The structural response of naval surface ships subjected to underwater shock loadings is a very important problem in viewpoint ship survivability. In practice, among others the case of noncontact underwater explosions is the only one shock loading considered in designing naval surface ships to resist underwater explosions. In orator to efficiently design naval surface ships and their equipment to resist such shock loadings it seems necessary to prepare theoretical analysis tools and/or empirical design criteria which can predict the three dimensional transmission of shock waves. This paper describes a simplified method to analyse shock responses for ship hull girder, which uses a loading function to approximate the shock loadings on ship structures due to noncontact underwater explosions. A couple of examples to apply this method are provided.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.117-122
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• 2001

The shock test of shipboard equipments is performed for the evaluation of the shock-resistant. capability by analyzing the maximum acceleration, the effective time duration and the shock response spectrum, etc. But some measured signals have impulsive noise and gaussian white noise because of the ambient noise, the acquisition equipment error and the transient movement of cables during the shock test. The improved transient signal analysis method which removes the noise of measured signal using the threshold policy of the median filter and the orthogonal wavelet coefficients is proposed. It was verified that the signal-to-noise ratio was improved about 30dB by the numerical simulation. And the shock response spectrum was extracted using the denoised shock response signal which was applied by this proposed method.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.44-56
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• 1993

The purpose of this paper is to analyze the impact response behaviors of glass/epoxy laminated composite plates subjected to the transversely impact of a steel ball. For this purpose, dynamic finite element analysis based on the higher-order shear defomation plate theory is used to compute the contact forces, rebound velocity of a steel ball, and dynamic strain response histories. And low-velocity and high-velocity impact experiments were conducted to compare the results and compute the wave propagation velocities. The results obtained from impact experiments are in good agreement with those of dynamic finite element analysis. Also the wave propagation velocities obtained from high-velocity impact experiments and wave propagation theory agree well, and wave velocities were higher in the smaller radius of steel ball.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.8
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• pp.41-46
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• 2006

The capability for reconstructing impact forces of an aircraft wing using impact response functions and regularization methods were examined. The impact response function which expresses the relation between the structure response and the impact force was derived using the information on mass and stiffness data of a finite element model for the wing. Iterative Tikhonov regularization method and generalized singular value decomposition method were used to inverse the impact response function that was generally ill-posed. For the numerical verification, a fighter aircraft wing was used. Strain and deflection histories obtained from finite element analysis were compared with the results calculated using impact response functions. And the impact forces were reconstructed with the strain histories obtained from finite element analysis. The numerical verification results showed that this method can be used to monitor impact forces on aircraft structures.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.557-560
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• 2004

본 논문에서는 실내음향을 측정하기 위해 사용되는 음향 측정 신호인 blank pistol, maximum length sequence, sine sweep 을 이용한 충격응답 특성을 분석한다. 각 충격응답의 실내음향 인자들을 먼저 비교 분석하고 sine sweep 속도에 따른 충격응답 특성을 분석하여 최적의 실내음향 인자를 찾기 위한 sine sweep 속도를 결정한다.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.97-105
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• 2001

현장타설말뚝의 건전도 평가에서 충격반향, 충격응답기법과 같은 비검측공 시험법을 적용하는 사례가 점차로 증가되는 추세에 있다. 비검측공시험법의 적용성을 체계적으로 평가하기 위해 수행된 일련의 연구결과 중에서 본 논문에서는 시험법의 결함탐지 능력을 평가하기 위해 수행된 해석적 연구결과에 관해 논한다. 이 연구에서는 시험법의 결함탐지능력에 대한 제반 영향인자 중에서 결함의 유형, 위치 및 크기의 영향을 평가하고자 하였다. 이를 위해서 여러 가지 조건에서 말뚝머리에 작용하는 충격하중에 대한 흙-말뚝 구조의 동적응답을 ABAQUS를 이용한 유한요소법으로 해석하였다. 이로부터 얻은 신호를 충격반향 혹은 충격응답기법으로 처리.분석하여 각 시험법의 결함탐지 능력을 평가해 보았다. 연구결과 이들 두 기법 모두 결함의 위치와 유형은 비교적 정확하게 탐지하는 것으로 나타났다. 그러나 충격응답기법을 이용하여 추정한 결함 크기는 신뢰도가 매우 낮았다. 이 문제를 해소하여 시험법의 적용성을 향상시키기 위해서는 측정된 동적응답신호를 이용하여 적절한 역계산 기법을 개발하여 적용할 필요가 있다는 결론을 얻었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.105-113
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• 2018

The proposed model to predict the bridge load carrying capacity uses the impact response spectrum. The spectrum is based on Euler-Bernoulli beam and the center of the bridge width for the moving load location. Therefore, it is necessary to investigate the eccentric moving load effects on the impact factor and response factor. For this, this study considers 10 m width and two-lane simply supported slab bridges and performs the moving load analysis to investigate the variations of peak impact factor and corresponding response factor. The numerical results show that the eccentric load increases both the static and dynamic displacements, but the impact factor is decreased since the incremental amount of static displacement is bigger than that of dynamic displacement. However, the difference of the impact factors between the center and eccentric loadings is small showing less than 0.5%p. In the response factor, the eccentric loading increases both the static and dynamic response factors, compared to the center loading. The difference of the response factor is only 0.18%p. It shows that the eccentric loading has very small effects on the response factor, thus the impact factor response spectrum which is generated based on the center moving load can be used to determine the response factor.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.3.2-6
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• 1998

본 논문에서는 실측된 실내 충격 응답을 모델링하여 실내 잔향 필터 설계를 시도하였다. 급강하법(steepest descent method)을 이용하여 측정된 실내 충격 응답을 4개의 콤 필터(comb filter)와 2개의 올패스 필터(allpass filter)로 이루어진 잔향 필터로 모델링하여, 잔향 필터의 계수를 결정하였다.