• Title, Summary, Keyword: 감쇄함수

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Sensitivity Analysis of HAZUS Results Attenuation (지진파 감쇄식에 대한 민감도 분석 연구 (HAZUS))

  • Oh, Tae-Seok;Kim, Jun-Kyoung;Kang, Ik-Bum;Yoo, Seong-Hwa
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.247-252
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    • 2006
  • This study analysed the sensitivity of the attenuation functions for the seismic hazard estimation. For the seismic hazard estimation, this study used HAZUS software, which is developed originally by FEMA(USA). The scenario earthquake ($M_w=6.0$) is located the Hongsung area, where one of the recent macro earthquakes occurred in 1978. The area for seismic hazard estimation is assumed to be Boryung city in Choongnam-do. Three attenuation functions were applied for the sensitivity analysis. The results show that the attenuation functions have much influences on the seismic hazard on the various types of buildings. Therefore the attenuation function is very important factor for the seismic hazard estimation.

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An empirical study on the effect of distance decay for the relocated firms using distance-decay function by industrial types in the Seoul Metropolitan Area (거리조락함수를 이용한 수도권 지역간 기업이동 거리감쇄효과 실증 연구)

  • An, Youngsoo;Lee, Seungil
    • Journal of the Korean Regional Science Association
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    • v.31 no.2
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    • pp.47-61
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    • 2015
  • The purpose of this study to empirical analysis of the effects of distance-decay for the relocated firms in the Seoul Metropolitan Area(SMA). In addition, this study was constructed distance-decay function for the relocated firms by industrial types using a general distance-decay function. The data of relocated firms in the SMA extracted from the spatial database which was constructed in an previous research. The industrial type divided into 3 parts which are construction, manufacturing, and service. The result of empirical analysis by each industrial type of the effect of distance-decay, the explanatory power($R^2$) of the each function were all high. In the construction, the adjusted $R^2$ of the distance-decay function was 0.728, the manufacturing was 0.802 and the service was 0.812. It means the effect of distance decay for the relocated firms in construction industrial type more big than the effects of distance decay for the manufacturing and service industrial types.

On the Distribution of Phase Error in the Rician Fading Channel (라이시안 감쇄 채널에서의 위상오류 분포)

  • 김민종;한영열
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.8
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    • pp.797-803
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    • 2002
  • In this paper we derive the probability density function of the phase error of the received signal over Rician fading channel and verify its propriety as the probability density function using the zeroth moment. In general, for the error probability over fading channel we compute the error probability in the first place when it is only AWGN, and then we get the final result by averaging the first result and the probability density function of the corresponding fading channel. In this paper, however, we compute the error probability by double integration after the probability density function over fading channel is computed.

Review of the Transfer Function and Coupling Configuration for Microwave Filter (마이크로파 필터의 전달 함수 및 결합 구조 고찰)

  • Uhm, M.S.;Lee, J.S.;Yom, I.B.;Lee, S.P.
    • Electronics and Telecommunications Trends
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    • v.18 no.2
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    • pp.67-78
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    • 2003
  • 모든 RF 통신 시스템에서 사용되는 마이크로파 필터는 통과 대역에서 에너지를 전달하고, 저지 대역에서 에너지를 감쇄시키는 역할을 한다. 주파수 사용 효율을 높이기 위해서 대역내 평탄도 및 군지연 특성이 우수하고, 대역외에서 높은 감쇄를 갖는 필터 개발에 많은 연구가 이루어졌다. 본 고에서 필터 개발에 필수적인 전달 함수 특성 및 결합 구조에 관하여 고찰한다.

Study on the Formulation of Two Dimensional Infinite Elements (이차원 무한요소 형성에 관한 연구)

  • 신용태;임장근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.5
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    • pp.1066-1073
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    • 1993
  • Using regular finite elements and infinite elements simultaneously, elastic boundary value problems with infinite domain can be analyzed more effectively and accurately. In this paper, two dimensional infinite elements have been formulated by means of applying the derived mapping function to the coordinates and multiplying the regular displacement shape functions by a decay function. Orders(m, n) of the mapping and decay functions are found for the purpose of obtaining the convergent solutions without respect to the various decay lengthes. As a result of numerical tests for an infinite plate with a hole under internal pressure, two sets of function orders are obtained as follows. (a) n=0, m=1.5 (b) n=m=0.65

Distribution of the Phase Error and the Envelope of the Received Signal over Nakagami Fading Channel (나카가미 감쇄 채널에서 수신 신호의 위상오류 분포와 포락선 분포)

  • 임채헌;한영열
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.6
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    • pp.825-834
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    • 1999
  • In this paper we derive the probability density function of the phase error and that of the envelope of the received signal over Nakagami fading channel. Using the new probability density functions we analyze the performance of coherent BPSK, noncoherent FSK, DPSK and noncoherent ASK on Nakagami fading by means of new methods.

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Unconditionally Stable Analysis of Transient Scattering from Conductors Using Time-Domain Combined Field Integral Equations (시간영역 결합적분식을 이용한 도체 과도산란의 무조건 안정된 해석)

  • 정백호;서정훈;이원우
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.8
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    • pp.340-348
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    • 2003
  • In this paper, we propose a novel formulation to solve a time-domain combined field integral equation (CFIE) for analyzing the transient electromagnetic scattering response from closed conducting bodies. Instead of the conventional marching-on in time (MOT) technique, tile solution method in this paper is based on the moment method that involves separate spatial and temporal testing procedures. Triangular patch vector functions are used for spatial expansion and testing functions for three-dimensional arbitrarily shaped closed structures. The time-domain unknown coefficient is approximated as a basis function set that is derived from tile Laguerre functions with exponentially decaying functions. These basis functions are also used as the temporal testing. Numerical results computed by the proposed method arc stable without late-time oscillations and agree well with the frequency-domain CFIE solutions.

Development of Attenuation Equations of ground Motions in the Southern Part of the Korean Peninsula (한반도 남부 지역의 지진동 감쇄식 개발)

  • 노명현
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.1
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    • pp.21-28
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    • 1999
  • The objective of the study is to develop attenuation equations of the ground motions in the southern part of the Korean peninsula. The earthquake source characteristics and the medium properties were estimated from available instrumental earthquake records and used as input parameters. The peak ground accelerations(PGA) and pseudo-velocity response spectra(PSV) were simulated by the random vibration theory. The attenuation equations for the PGA and PSV were constructed in terms of local magnitudes and hypocentral distances.

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Attenuation Estimation of Soft Tissue by the Entropy Method and Statistical Averaging of Speckle Patterns (스펙클 패턴의 통계적 평균과 엔트로피 방식에 의한 초음파 감쇄계수 추정방법)

  • Song, T.K;Park, J.C;Park, S.B
    • Journal of Biomedical Engineering Research
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    • v.10 no.3
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    • pp.253-260
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    • 1989
  • The time domain methods of estimating the attenuation coefficient are generally based on the analysis of statisical properties of the reflected echoes form an attenuating medium. Hence, it is often required to have a large number of data samples in order to obtain a statistically stable estimation result. In the attenuation estimation problem, this means that many different speckle patterns are required in the spatial resolution volume of an attenLlation image. In this paper, by using the fact that the speckle pattern Is sensitive to the point spread function of the ultrasound beam, we suggest a method to generate the statiscally uncorrelated or slightly correlated data samples in a given region by rotating a linear transducer and carrying out lateral scans for all rotating angles. This technique is applied to the entropy method for attenuation estimation proposed recently by the authors where the performance is verified by experiments using a tissue equivalent phantom.

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Multipath Error Mitigation using Differenced Autocorrelation Function (자기 상관 차분 함수를 이용한 다중 경로 오차 감쇄 기법)

  • 최일흥;이상정
    • Journal of the Korea Institute of Military Science and Technology
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    • v.6 no.1
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    • pp.59-67
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    • 2003
  • Multipath is an inevitable error source in radio navigation system such as GPS, it causes signal tracking errors such as carrier tracking errors, code tracking errors. Since code tracking error is a dominant error in absolute positioning, this paper focuses on the improvement of code tracking performance. This paper proposes a method that detects the change of autocorrelation function's slope and mitigates the multipath error. Also, this paper shows the performance evaluation results by post-processing the digitized RF samples.