• Title/Summary/Keyword: spectral function

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Predictive Control of Structural Vibration Subject to Wind Loads (풍하중에 대한 구조진동의 예측제어)

  • 최창근;권대건;이은진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.10a
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    • pp.29-36
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    • 1996
  • A procedure for the predictive control for structural vibration control in building subject to wind loads is presented. The building motions are modeled by the first mode of the response. Wind velocities are generated by the simulation using power spectral density function. Predictive control algorithm is the discrete-time formulation and that is developed as a control strategy that computes the control signal which makes the predicted process output equal to a desired process output. Results on the reduction of the dynamic response and control effectiveness of the algorithm are presented and discussed.

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Radiation Characteristics of Microstrip Antenna on the Cylindrical Bianisotropic Substrates Loaded bianisotropic superstrate

  • Yoon, Joong-Han;Lee, Sang-Mok;Park, Byung-Ha
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.885-888
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    • 1999
  • Radiation characteristics of axial elementary current source on the cylindrical bianisotropic substrateloaded with bianisotropic superstrate layer are presented. The effects of bianisotropic superstrate cover on the radiation problems of a microstrip antenna are studied. This investigation is performed by using the Green function formulation in the spectral domain. Numerical results for the radiation pattern of the bianisotropic superstrate-loaded microstrip antenna is analyzed.

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Fault Analysis and Detection of Ternary Logic (3차 논리회로의 고정분석 및 검출)

  • 김종오;김영건;김흥수
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.12
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    • pp.1552-1564
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    • 1995
  • A fault detecting method of ternary logic is proposed by using the spectral coefficients of the Chrestenson function. Fault detecting conditions are derived for a stuck-at fault in case of single input, multiple inputs and internal lines in the ternary logic. The detecting conditions for min/max bridging faults are also considered. When using this fault analysis method, it is possible to detect faults without the test vector and minimize high volume memory for storing the vector and response data. Thus, the computational complexity for the test vector can be decreased.

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PAPR reduction algorithm using Hadamard transform and phase shift in OFDM systems (Hadamard 변환과 위상 천이를 이용한 OFDM 시스템의 PAPR 감소 기법)

  • 구현철
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.233-236
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    • 2001
  • Orthogonal freqency division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless data transmission. However, the potentially large peak-to-average power ratio (PAPR) has limited its application; An OFDM signal with the large PAPR can cause power degradation (In-band distortion) and spectral spreading (Out-of-band distortion) by being clipped passing through a power amplifier. Thus, we propose the combining algorithm of Hadamard transform and phase shift, which is ascribed to the relation between the correlation of the IFFT input sequence function and PAPR. Extensive computer simulations show that the combining algorithm is an effective technique to reduce PAPR.

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Perfect Reconstruction in Sub-Nyquist Nonuniform Sampling of Signals with Known upper Time-frequency Boundary (비 균일 표본화 신호의 완전 복구에 관한 연구)

  • 이희영;정현권
    • Proceedings of the IEEK Conference
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    • 2002.06e
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    • pp.9-12
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    • 2002
  • The problem of sub-Nyquist nonuniform sampling for the perfect reconstruction of signals with time-varying spectral contents is studied. The signals are assumed to have a known instantaneous bandwidth in time-frequency domain. As the function of time, the nonuniform sampling pattern of a given signal, that is, the instantaneous sampling frequency is determined by the observation of instantaneous bandwidth based on time-frequency analysis. The proposed sampling pattern guarantees the perfect reconstruction of nonuniform sampled signals under Nyquist-sampling rate in average.

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Stability of SA Fragility Curves on Elastic Modulus (탄성계수에 대한 SA 손상도 곡선의 안정성)

  • Lee, Jong-Heon
    • Journal of the Korean Society of Industry Convergence
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    • v.9 no.3
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    • pp.207-214
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    • 2006
  • In this paper, the stability of SA(Spectral Acceleration) fragility curves is studied for the two sets of elastic modulus of concrete. In doing that, general purpose structural analysis program and generally used probability density function are used. The results of structural analysis are represented by Bernoulli distribution which says damage or no damage. By the use of Maximum Likelihood Method, two parameters of lognormal distribution - median and standard deviation - are found. With them, the fragility curves are constructed.

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A NONHARMONIC FOURIER SERIES AND DYADIC SUBDIVISION SCHEMES

  • Rhee, Jung-Soo
    • East Asian mathematical journal
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    • v.26 no.1
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    • pp.105-113
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    • 2010
  • In the spectral analysis, Fourier coeffcients are very important to give informations for the original signal f on a finite domain, because they recover f. Also Fourier analysis has extension to wavelet analysis for the whole space R. Various kinds of reconstruction theorems are main subject to analyze signal function f in the field of wavelet analysis. In this paper, we will present a new reconstruction theorem of functions in $L^1(R)$ using a nonharmonic Fourier series. When we construct this series, we have used dyadic subdivision schemes.

Implementation of Communication Unit for KOMPSAT-II (다목적실용위성 2호기의 통신 부호화기 구현)

  • 이상택;이종태;이상규
    • Proceedings of the IEEK Conference
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    • 2003.11c
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    • pp.378-381
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    • 2003
  • The Channel Coding Unit (CCU) is an integral component of Payload Data Transmission System (PDTS) for the Multi-Spectral Camera (MSC) data. The main function of the CCU is channel coding and encryption. CCU has two channels (I & Q) for data processing. The input of CCU is the output of DCSU (Data Compression & Storage Unit). The output of CCU is the input of QTX which modulate data for RF communication. In this paper, there are the overview, short H/W description and operation concept of CCU.

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A Study on Cellular Communication with Frequency Hopping Technique (주파수 도약 기술을 이용한 셀루라 통신에 관한 연구)

  • 진봉철;박상규;한영열
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.6
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    • pp.517-532
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    • 1991
  • This paper shows performance analysis for FH/MF나 systems over the cellular mobile communication channel. The Channel capacity over FH/MF나 system is represented as a function of deletion probalblity (Po) and insertion probalbility(Pt). The spectral efficiency of the system serves as a per formance of cellular system is inferior to that of non cellular system. In the case of frequency reuse, we get the best performance when the reuse pattern(N) is 3.

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Adaptive Wavelet Denoising For Speech Rocognition in Car Interior Noise

  • 김이재;양성일;Kwon, Y.;Jarng, Soon S.
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.4
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    • pp.178-178
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    • 2002
  • In this paper, we propose an adaptive wavelet method for car interior noise cancellation. For this purpose, we use a node dependent threshold which minimizes the Bayesian risk. We propose a noise estimation method based on spectral entropy using histogram of intensity and a candidate best basis instead of Donoho's best bases. And we modify the hard threshold function. Experimental results show that the proposed algorithm is more efficient, especially to heavy noisy signal than conventional one.