• Title/Summary/Keyword: 분해기법

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Underwater Transient Signal Detection Using Higher-order Statistics and Wavelet Analysis (고차통계 기법과 웨이브렛을 이용한 수중 천이신호 탐지)

  • 조환래;오선택;오택환;나정열
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.8
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    • pp.670-679
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    • 2003
  • This paper deals with application of wavelet transform, which is known to be good for time-frequency analysis, in order to detect the underwater transient signals embedded in ambient noise. A new detector of acoustic transient signals is presented. It combines two detection tools: wavelet analysis and higher-order statistics. Using both techniques, the detection of the transient signal is possible in low signal to noise ratio condition. The proposed algorithm uses the wavelet transform of a partition of the signal on frequency domain, and then higher-order statistics tests the Gaussian nature of the segments.

Signal Processing for Improvement of Resolution and Direction Ambiguity of Source in Line Array (선 배열에서 표적체의 방위 모호성과 분해능 향상을 위한 신호처리 기법)

  • 손윤준;천승용;김기만
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.6
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    • pp.482-488
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    • 2003
  • Line may receiver contains an ambiguity on conjugate bearings, because of lacking aperture in transverse direction. To solve the left/right bearing ambiguity of line-array receiver we used line-array with cardioid beam. In addition, the synthetic aperture method adopts coherent processing of sub-aperture signals at successive time intervals in the beam domain. We presented performances about division of left/right bearing ambiguity according to array synthetic number of times in this paper.

The Function Construction based on Modular Design Technique (모듈러 설계기법에 기초한 함수구성)

  • Park, Chun-Myoung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.918-919
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    • 2012
  • This paper present a method of function decomposition and input variable manipulation method based on modular design techniques. We obtain the column multiplicity of decomposition function according to row decomposition method. Also, the proposed partial decomposition function have advantage which is able to omit control function using t-Gate. We find the advantage for internal connection decrement 12% and T-gate number 16%, therefore we find the simple design circuit.

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Online Monaural Ambient Sound Extraction based on Nonnegative Matrix Factorization Method for Audio Contents (오디오 컨텐츠를 위한 비음수 행렬 분해 기법 기반의 실시간 단일채널 배경 잡음 추출 기법)

  • Lee, Seokjin
    • Journal of Broadcast Engineering
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    • v.19 no.6
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    • pp.819-825
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    • 2014
  • In this paper, monaural ambient component extraction algorithm based on nonnegative matrix factorization (NMF) is described. The ambience component extraction algorithm in this paper is developed for audio upmixing system; Recent researches have shown that they can enhance listener envelopment if the extracted ambient signal is applied into the multichannel audio upmixing system. However, the conventional method stores all of the audio signal and processes all at once, so it cannot be applied to streaming system and digital signal processor (DSP) system. In this paper, the ambient component extraction algorithm based on on-line nonnegative matrix factorization is developed and evaluated to solve the problem. As a result of analysis of the processed signal with spectral flatness measures in the experiment, it was shown that the developed system can extract the ambient signal similarly with the conventional batch process system.

Stochastic disaggregation of daily rainfall based on K-Nearest neighbor resampling method (K번째 최근접 표본 재추출 방법에 의한 일 강우량의 추계학적 분해에 대한 연구)

  • Park, HeeSeong;Chung, GunHui
    • Journal of Korea Water Resources Association
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    • v.49 no.4
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    • pp.283-291
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    • 2016
  • As the infrastructures and populations are the condensed in the mega city, urban flood management becomes very important due to the severe loss of lives and properties. For the more accurate calculation of runoff from the urban catchment, hourly or even minute rainfall data have been utilized. However, the time steps of the measured or forecasted data under climate change scenarios are longer than hourly, which causes the difficulty on the application. In this study, daily rainfall data was disaggregated into hourly using the stochastic method. Based on the historical hourly precipitation data, Gram Schmidt orthonormalization process and K-Nearest Neighbor Resampling (KNNR) method were applied to disaggregate daily precipitation into hourly. This method was originally developed to disaggregate yearly runoff data into monthly. Precipitation data has smaller probability density than runoff data, therefore, rainfall patterns considering the previous and next days were proposed as 7 different types. Disaggregated rainfall was resampled from the only same rainfall patterns to improve applicability. The proposed method was applied rainfall data observed at Seoul weather station where has 52 years hourly rainfall data and the disaggregated hourly data were compared to the measured data. The proposed method might be applied to disaggregate the climate change scenarios.

Effective Decentralized Sampled-Data Control for Nonlinear Systems in T-S' Form: Overlapping IDR Approach (타카기-수게노 형태의 비선형 시스템의 효율적 분산 샘플치 제어: 중복 지능형 디지털 재설계 접근법)

  • Lee, Ho-Jae;Kim, Do-Wan
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.1
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    • pp.94-99
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    • 2012
  • This paper discusses a decentralized sampled-data control problem for large-scale nonlinear systems. The system is represented in Takagi-Sugeno's form. Next, we design a decentralized analog controller based on the overlapping decomposition technique. The final step is to apply the intelligent digital redesign scheme for converting the analog controller into the sampled-data one. Design condition is represented in terms of linear matrix inequalities. A simulation result is provided for the effectiveness of the proposed design method.

Uncertainty decomposition in water resources projection considering interaction effects (교호작용 효과를 고려한 수자원 전망의 불확실성 분해)

  • Ohn, Ilsang;Kim, Yongdai;Kim, Young-Oh
    • Journal of Korea Water Resources Association
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    • v.51 no.spc
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    • pp.1067-1078
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    • 2018
  • Water resources projection typically consists of several stages including emission scenarios, global circulation models (GCMs), downscaling techniques, and hydrological models, and each stage is a source of total uncertainty in water resources projection. Several studies proposed methods to quantify the relative contribution of each stage to total uncertainty, and we call such analysis uncertainty decomposition. Uncertainty decomposition enables us to investigate the stages yielding large uncertainties and to establish the uncertainty reduction plan that reflects them. Interactions between stages is one of the important issues to be considered in uncertainty decomposition. This study suggests a new uncertainty decomposition method considering interaction effect. The proposed method has an advantage of decomposing the total uncertainty to the uncertainty from each stage considering both the main and interactions effects. We apply the proposed method to streamflow projection for Chungju Dam basin. The results show that the uncertainties from the main effects are larger than the uncertainties from interaction effects in both summer and winter. Using the proposed uncertainty decomposition method, we show that the GCM stage is the largest source of the total uncertainty in summer and the downscaling technique stage is the one in winter among the following four stages: emission scenarios, GCMs, downscaling techniques, and hydrological models.

Security Analysis of ElGamal-Type Signature Scheme Using Integer Decomposition (정수의 분해를 이용한 ElGamal형 서명기법의 안전성 분석)

  • 이익권;김동렬
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.14 no.2
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    • pp.15-22
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    • 2004
  • For an ElGamal-type signature scheme using a generate g of order q, it has been well-known that the message nonce should be chosen randomly in the interval (0, q-1) for each message to be signed. In (2), H. Kuwakado and H. Tanaka proposed a polynomial time algorithm that gives the private key of the signer if two signatures with message nonces 0<$k_1$, $k_2$$\leq$Ο(equation omitted) are available. Recently, R. Gallant, R. Lambert, and S. Vanstone suggested a method to improve the efficiency of elliptic curve crytosystem using integer decomposition. In this paper, by applying the integer decomposition method to the algorithm proposed by Kuwakado and Tanaka, we extend the algorithm to work in the case when |$k_1$ |,|$k_2$, |$\leq$Ο(equation mitted) and improve the efficiency and completeness of the algorithm.