• Title/Summary/Keyword: 가우시안 랜덤변수

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Blind Equalization based on Maximum Cross-Correntropy Criterion using a Set of Randomly Generated Symbol (랜덤 심볼을 사용한 최대 코렌트로피 기준의 블라인드 등화)

  • Kim, Nam-Yong;Kang, Sung-Jin;Hong, Dae-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1C
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    • pp.33-39
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    • 2010
  • Correntropy is a generalized correlation function that contains higher order moments of the probability density function (PDF) than the conventional moment expansions. The criterion maximizing cross-correntropy (MCC) of two different random variables has yielded superior performance particularly in nonlinear, non-Gaussian signal processing comparing to mean squared error criterion. In this paper we propose a new blind equalization algorithm based on cross-correntropy criterion which uses, as two variables, equalizer output PDF and Parzen PDF estimate of a set of randomly generated symbols that complies with the transmitted symbol PDF. The performance of the proposed algorithm based on MCC is compared with the Euclidian distance minimization.

Variational Bayesian Methods for Learning HMM with Mixture of Gaussian Outputs (가우시안 혼합 출력 HMM을 위한 변분 베이지안 방법)

  • O Jangmin;Zhang Byoung-Tak
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.07b
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    • pp.619-621
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    • 2005
  • 은닉 마코프 모델은 이산 동역학을 표현할 수 있는 확률 모형이다. 우도 함수 최적화를 수행하는 전통적인 Baum-Welch 학습 알고리즘은 국소해로 수령하기 쉬우며, 우도함수의 특성상 복잡한 모델을 선호하는 바이어스가 존재한다. 베이지안 프레임워크에서는 파라미터를 랜덤 변수로 보고 이에 대한 사후 확률 분포를 추정하여 이 문제를 해결할 수 있다. 본 논문에서는 베이지안 추정을 위한 결정론적 근사화 기법인 변분 베이지안 방법을 이용, 출력 노드에 가우시안 혼합 노드를 지니는 일반화된 HMM의 추론 방법을 유도한다. 인공 데이터에 대한 실험을 통해, 본 방법이 효과적인 HMM 학습을 수행할 수 있음을 보인다.

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Adaptive State Feedback Control using Online Least Square Estimation for Time-varying DC Motor Systems (시변 직류 모터 시스템을 위한 온라인 최소자승 추정법 기반 적응형 상태궤환 제어기)

  • Cho, Hyun-Cheol;Kim, Kwang-Soo;Lee, Young-Jin;Lee, Kwon-Soon
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1682-1683
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    • 2007
  • 본 논문은 시변 파라미터를 갖는 직류 모터의 적응 제어를 위한 온라인 상태궤환 제어시스템을 구성한다. 모터의 전기자 저항은 공칭값에 대하여 가우시안 랜덤변수로 가정하고 온라인 최소자승 추정법을 이용하여 실시간으로 추정한다. 모터의 부하 토크 또한 시변 특성을 가지며 이런 시스템 환경의 변화에 대해서도 설정치를 잘 추종하는 특성을 갖도록 한다. 컴퓨터 시뮬레이션을 통해 제어기법의 타당성을 검증하며 기존의 상태궤환 제어기법과 비교분석하여 성능의 우수성을 입증한다.

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MRF-based Adaptive Noise Detection Algorithm for Image Restoration (영상 복원을 위한 MRF 기반 적응적 노이즈 탐지 알고리즘)

  • Nguyen, Tuan-Anh;Hong, Min-Cheol
    • Journal of Korea Multimedia Society
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    • v.16 no.12
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    • pp.1368-1375
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    • 2013
  • In this paper, we presents a spatially adaptive noise detection and removal algorithm. Under the assumption that an observed image and the additive noise have Gaussian distribution, the noise parameters are estimated with local statistics, and the parameters are used to define the constraints on the noise detection process, where the first order Markov Random Field (MRF) is used. In addition, an adaptive low-pass filter having a variable window sizes defined by the constraints on noise detection is used to control the degree of smoothness of the reconstructed image. Experimental results demonstrate the capability of the proposed algorithm.

Mathematical Modelling of Happiness and its Nonlinear Analysis (행복의 수학적 모델링과 비선형 해석)

  • Kim, Soon-Whan;Choi, Sun-Koung;Bae, Young-Chul;Park, Young-Ho
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.6
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    • pp.711-717
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    • 2014
  • Happiness has been studied in sociology and psychology as a matter of grave concern. In this paper the happiness model that a new second -order systems can be organized equivalently with a Spring-Damper-Mass are proposed. This model is organized a 2-dimensional model of identically type with Duffing equation. We added a nonlinear term to Duffing equation and also applied Gaussian white noise and period sine wave as external stimulus that is able to cause of happiness. Then we confirm that there are random motion, periodic motion and chaotic motion according to parameter variation in the new happiness model.

Estimation of Spatial Distribution Using the Gaussian Mixture Model with Multivariate Geoscience Data (다변량 지구과학 데이터와 가우시안 혼합 모델을 이용한 공간 분포 추정)

  • Kim, Ho-Rim;Yu, Soonyoung;Yun, Seong-Taek;Kim, Kyoung-Ho;Lee, Goon-Taek;Lee, Jeong-Ho;Heo, Chul-Ho;Ryu, Dong-Woo
    • Economic and Environmental Geology
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    • v.55 no.4
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    • pp.353-366
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    • 2022
  • Spatial estimation of geoscience data (geo-data) is challenging due to spatial heterogeneity, data scarcity, and high dimensionality. A novel spatial estimation method is needed to consider the characteristics of geo-data. In this study, we proposed the application of Gaussian Mixture Model (GMM) among machine learning algorithms with multivariate data for robust spatial predictions. The performance of the proposed approach was tested through soil chemical concentration data from a former smelting area. The concentrations of As and Pb determined by ex-situ ICP-AES were the primary variables to be interpolated, while the other metal concentrations by ICP-AES and all data determined by in-situ portable X-ray fluorescence (PXRF) were used as auxiliary variables in GMM and ordinary cokriging (OCK). Among the multidimensional auxiliary variables, important variables were selected using a variable selection method based on the random forest. The results of GMM with important multivariate auxiliary data decreased the root mean-squared error (RMSE) down to 0.11 for As and 0.33 for Pb and increased the correlations (r) up to 0.31 for As and 0.46 for Pb compared to those from ordinary kriging and OCK using univariate or bivariate data. The use of GMM improved the performance of spatial interpretation of anthropogenic metals in soil. The multivariate spatial approach can be applied to understand complex and heterogeneous geological and geochemical features.

Increasing Accuracy of Stock Price Pattern Prediction through Data Augmentation for Deep Learning (데이터 증강을 통한 딥러닝 기반 주가 패턴 예측 정확도 향상 방안)

  • Kim, Youngjun;Kim, Yeojeong;Lee, Insun;Lee, Hong Joo
    • The Journal of Bigdata
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    • v.4 no.2
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    • pp.1-12
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    • 2019
  • As Artificial Intelligence (AI) technology develops, it is applied to various fields such as image, voice, and text. AI has shown fine results in certain areas. Researchers have tried to predict the stock market by utilizing artificial intelligence as well. Predicting the stock market is known as one of the difficult problems since the stock market is affected by various factors such as economy and politics. In the field of AI, there are attempts to predict the ups and downs of stock price by studying stock price patterns using various machine learning techniques. This study suggest a way of predicting stock price patterns based on the Convolutional Neural Network(CNN) among machine learning techniques. CNN uses neural networks to classify images by extracting features from images through convolutional layers. Therefore, this study tries to classify candlestick images made by stock data in order to predict patterns. This study has two objectives. The first one referred as Case 1 is to predict the patterns with the images made by the same-day stock price data. The second one referred as Case 2 is to predict the next day stock price patterns with the images produced by the daily stock price data. In Case 1, data augmentation methods - random modification and Gaussian noise - are applied to generate more training data, and the generated images are put into the model to fit. Given that deep learning requires a large amount of data, this study suggests a method of data augmentation for candlestick images. Also, this study compares the accuracies of the images with Gaussian noise and different classification problems. All data in this study is collected through OpenAPI provided by DaiShin Securities. Case 1 has five different labels depending on patterns. The patterns are up with up closing, up with down closing, down with up closing, down with down closing, and staying. The images in Case 1 are created by removing the last candle(-1candle), the last two candles(-2candles), and the last three candles(-3candles) from 60 minutes, 30 minutes, 10 minutes, and 5 minutes candle charts. 60 minutes candle chart means one candle in the image has 60 minutes of information containing an open price, high price, low price, close price. Case 2 has two labels that are up and down. This study for Case 2 has generated for 60 minutes, 30 minutes, 10 minutes, and 5minutes candle charts without removing any candle. Considering the stock data, moving the candles in the images is suggested, instead of existing data augmentation techniques. How much the candles are moved is defined as the modified value. The average difference of closing prices between candles was 0.0029. Therefore, in this study, 0.003, 0.002, 0.001, 0.00025 are used for the modified value. The number of images was doubled after data augmentation. When it comes to Gaussian Noise, the mean value was 0, and the value of variance was 0.01. For both Case 1 and Case 2, the model is based on VGG-Net16 that has 16 layers. As a result, 10 minutes -1candle showed the best accuracy among 60 minutes, 30 minutes, 10 minutes, 5minutes candle charts. Thus, 10 minutes images were utilized for the rest of the experiment in Case 1. The three candles removed from the images were selected for data augmentation and application of Gaussian noise. 10 minutes -3candle resulted in 79.72% accuracy. The accuracy of the images with 0.00025 modified value and 100% changed candles was 79.92%. Applying Gaussian noise helped the accuracy to be 80.98%. According to the outcomes of Case 2, 60minutes candle charts could predict patterns of tomorrow by 82.60%. To sum up, this study is expected to contribute to further studies on the prediction of stock price patterns using images. This research provides a possible method for data augmentation of stock data.

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Lattice Code of Interference Alignment for Interference Channel with 3 Users in CoMP (세 명의 사용자의 간섭 채널을 위한 협력 다중점 송수신(CoMP)에서의 격자(Lattice) 부호 간섭 정렬)

  • Lee, Moon-Ho;Peng, Bu Shi
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.27-38
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    • 2012
  • In this paper, we introduce CoMP in 3GPP LTE-Advanced Release 11 to take care of shadowing effects appearing in cell-edge areas to meet rapidly increasing demand for high speed transmission and multi-media data. In order to mitigate interference, orthogonalizing is ideal but it is slightly difficult to be applied to real systems. Therefore, interference alignment and avoidance are used in practical applications. Interference alignment is a scheme enabling us to consider interference our friend not enemy. We show lattice codes in Gaussian channel achieve Shannon capacity where strong interference exists. In addition, we show the relationship between channel parameter a and DoF(Degree of Freedom) applying lattice codes to interference alignment for interference channel with three users.

유기물에서 내부의 트랩 분포 변화에 따른 전자 이동도 현상

  • Yu, Ju-Hyeong;Kim, Dong-Hun;Kim, Tae-Hwan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.416-416
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    • 2012
  • 유기물을 기반으로 하는 유기발광소자, 유기메모리 및 유기 태양전지 등과 같은 차세대 전자소자는 기존의 무기물 기반의 소자에 비해 가격이 싸고 제작방법이 간단하며 휘어지게 만들 수 있다는 장점을 갖기 때문에 많은 관심을 받고 있다. 유기물을 기반으로 한 전자 소자의 효율을 향상시키기 위해서는 유기물질이 갖는 고유의 물리적 특성에 관한 연구가 중요하다. 특히, 유기물 내에서의 전하 전송 메카니즘을 이해하기 위해 유기물의 전자 이동도에 대한 연구가 중요하나, 아직까지 유기물질을 기반으로 한 전자 소자의 전자 이동도에 대한 이론적인 연구가 비교적 적다. 본 연구에서는 유기물 내에서의 트랩 분포 변화에 따른 전자 이동도를 몬테카를로 방법을 이용하여 계산하였다. 시뮬레이션을 위한 기본 구조로 소자의 길이는 30-300 사이트로 하였으며, 이웃한 사이트간 거리는 $3{\acute{\AA}}$로 결정하였다. 유기물 내에 존재하는 트랩의 분포는 가우시안 분포로 가정하였고, 트랩의 분산도와 트랩 총량을 변화시켜 계산하였다. 이웃한 트랩간의 천이 확률을 Miller and Abrahams 식을 이용하여 계산하고, 트랩간의 천이시간을 랜덤 변수로 결정하였고, 이들을 통계적으로 처리하여 유기물 내에서의 전자 이동도를 계산하였다. 시뮬레이션 결과는 유기물의 트랩분포가 일정할 경우 전자 이동도는 전계가 증가함에 따라 일정하게 증가하다가 일정 전계에서 포화된 후 다시 감소한다. 초기의 전계 영역에서는 전계의 증가에 따라 유기물 내 트랩간의 천이 확률이 증가하기 때문에 전자 이동도가 증가한다. 하지만, 일정 전계 이상에서는 전자의 이동 속도가 거의 변하지 않기 때문에, 전계의 증가에 따라 전자 이동도는 오히려 줄어들게 된다. 트랩의 분산도가 증가함에 따라 낮은 전계 영역에서는 전자 이동도가 작고, 전계가 증가할수록 분산도와 상관없이 전자 이동도가 비슷한 값으로 수렴한다. 트랩의 분산도가 30 meV로 작을 경우에 일정 온도 이상에서의 전자 이동도는 포화되어 일정한 값으로 유지한다. 유기물 내에 존재하는 트랩 분포에 따라 온도의 변화가 전자 이동도에 미치는 영향이 달라짐을 알 수 있다. 이러한 결과는 유기물질을 기반으로 한 전자소자에서의 전하 전송 메카니즘을 이해하고 소자의 제작 및 특성 향상에 도움이 된다고 생각한다.

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Performance Analysis of Monopulse System Based on Third-Order Taylor Expansion in Additive Noise (부가성 잡음이 존재하는 모노펄스 시스템 성능의 3차 테일러 전개 기반 해석적 분석)

  • Ham, Hyeong-Woo;Kim, Kun-Young;Lee, Joon-Ho
    • Journal of Convergence for Information Technology
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    • v.11 no.12
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    • pp.14-21
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    • 2021
  • In this paper, it is shown how the performance of the monopulse algorithm in the presence of an additive noise can be obtained analytically. In the previous study, analytic performance analysis based on the first-order Taylor series and the second-order Taylor series has been conducted. By adopting the third-order Taylor series, it is shown that the analytic performance based on the third-order Taylor series can be made closer to the performance of the original monopulse algorithm than the analytic performance based on the first-order Taylor series and the second-order Taylor series. The analytic MSE based on the third-order Taylor approximation reduces the analytic MSE error based on the second-order Taylor approximation by 89.5%. It also shows faster results in all cases than the Monte Carlo-based MSE. Through this study, it is possible to explicitly analyze the angle estimation ability of monopulse radar in an environment where noise jamming is applied.