• Title/Summary/Keyword: Back propagation

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Improving the Error Back-Propagation Algorithm of Multi-Layer Perceptrons with a Modified Error Function (역전파 학습의 오차함수 개선에 의한 다층퍼셉트론의 학습성능 향상)

  • 오상훈;이영직
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.6
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    • pp.922-931
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    • 1995
  • In this paper, we propose a modified error function to improve the EBP(Error Back-Propagation) algorithm of Multi-Layer Perceptrons. Using the modified error function, the output node of MLP generates a strong error signal in the case that the output node is far from the desired value, and generates a weak error signal in the opposite case. This accelerates the learning speed of EBP algorothm in the initial stage and prevents overspecialization for training patterns in the final stage. The effectiveness of our modification is verified through the simulation of handwritten digit recognition.

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Tomogram Enhancement using Iterative Error Correction Algorithm

  • Ko, Dae-Sik;Park, Jun-Sok
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.4E
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    • pp.9-13
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    • 1996
  • We developed an iterative algorithm which could improve the resolution of reconstructed tomograms having random attenuation patterns and analyzed the limitation of this algorithm. The simple back-and forth propagation algorithm has depth resolution about four wavelengths. An iterative algorithm, based on back-and-forth propagation, can be used to improve the resolution of reconstructed tomograms. We analyzed the wavefield for multi-layered specimen and programmed iterative algorithm using Clanguage. Simulation results show that the images get clearer as the number of iterations increases. Also, unambiguous images can be reconstructed using this algorithm even when the layer separation is only two wavelengths. However, this iteration algorithm comes up with an incorrect solution for the number of projections less than five.

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Gabor-Features Based Wavelet Decomposition Method for Face Detection (얼굴 검출을 위한 Gabor 특징 기반의 웨이블릿 분해 방법)

  • Lee, Jung-Moon;Choi, Chan-Sok
    • Journal of Industrial Technology
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    • v.28 no.B
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    • pp.143-148
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    • 2008
  • A real-time face detection is to find human faces robustly under the cluttered background free from the effect of occlusion by other objects or various lightening conditions. We propose a face detection system for real-time applications using wavelet decomposition method based on Gabor features. Firstly, skin candidate regions are extracted from the given image by skin color filtering and projection method. Then Gabor-feature based template matching is performed to choose face cadidate from the skin candidate regions. The chosen face candidate region is transformed into 2-level wavelet decomposition images, from which feature vectors are extracted for classification. Based on the extracted feature vectors, the face candidate region is finally classified into either face or nonface class by the Levenberg-Marguardt back-propagation neural network.

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Dynamic Control of Track Vehicle Using Fuzzy-Neural Control Method (퍼지-뉴럴 제어기법에 의한 궤도차량의 동적 제어)

  • 한성현;서운학;조길수;윤강섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.133-139
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    • 1997
  • This paper presents a new approach to the dynamic control technique for track vehicle system using neural network-fuzzy control method. The proposed control scheme uses a Gaussian function as a unit function in the neural network-fuzzy, and back propagation algorithm to train the fuzzy-neural network controller in the framework of the specialized learning architecture. It is propored a learning controller consisting of two neural network-fuzzy based on independent resoning and a connection net with fixed weights to simply the neural network-fuzzy. The performance of the proposed controller is shown by simulation for trajectory tracking of the speed and azimuth of a track vehicle

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Comparison of the BOD Forecasting Ability of the ARIMA model and the Artificial Neural Network Model (ARIMA 모형과 인공신경망모형의 BOD예측력 비교)

  • 정효준;이홍근
    • Journal of Environmental Health Sciences
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    • v.28 no.3
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    • pp.19-25
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    • 2002
  • In this paper, the water quality forecast was performed on the BOD of the Chungju Dam using the ARIMA model, which is a nonlinear statistics model, and the artificial neural network model. The monthly data of water quality were collected from 1991 to 2000. The most appropriate ARIMA model for Chungju dam was found to be the multiplicative seasonal ARIMA(1,0,1)(1,0,1)$_{12}$, model. While the artificial neural network model, which is used relatively often in recent days, forecasts new data by the strength of a learned matrix like human neurons. The BOD values were forecasted using the back-propagation algorithm of multi-layer perceptrons in this paper. Artificial neural network model was com- posed of two hidden layers and the node number of each hidden layer was designed fifteen. It was demonstrated that the ARIMA model was more appropriate in terms of changes around the overall average, but the artificial neural net-work model was more appropriate in terms of reflecting the minimum and the maximum values.s.

Sensor Failure Detection and Accommodation Based on Neural Networks (신경회로망을 이용한 센서 고장진단 및 극복)

  • 이균정;이봉기
    • Journal of the Korea Institute of Military Science and Technology
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    • v.1 no.1
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    • pp.82-91
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    • 1998
  • This paper presents a neural networks based approach for the problem of sensor failure detection and accommodation for ship without physical redundancy in the sensors. The designed model consists of two neural networks. The first neural network is responsible for the failure detection and the second neural network is responsible for the failure identification and accommodation. On the yaw rate sensor of ship, simulation results indicates that the proposed method can be useful as failure detector and sensor estimator.

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Container Identifier Recognition System for GATE automation (GATE 자동화를 위한 컨테이너 식별자 인식 시스템)

  • 유영달;하성욱;강대성
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1998.10a
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    • pp.137-141
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    • 1998
  • Todays the efficient management of container has not been realized in container terminal, because of the excessive quantity of container transported and manual system. For the efficient and automated management of container in terminal, the automated container identifier recognition system in terminal is a significant problem. However, the identifier recognition rate is decreased owing to the difficulty of image preprocessing caused the refraction of container surface, the change of weather and the damaged identifier characters. Therefore, this paper proposes more accurate system for container identifier recognition as suggestion of Line-Scan Proper Region Detect for stronger preprocessing against external noisy element and Moment Back-Propagation Neural Network to recognize identifier.

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Comparison of Different Schemes for Speed Sensorless Control of Induction Motor Drives by Neural Network (유도전동기의 속도 센서리스 제어를 위한 신경회로망 알고리즘의 추정 특성 비교)

  • 이경훈;국윤상;김윤호;최원범
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.526-530
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    • 1999
  • This paper presents a newly developed speed sensorless drive using Neural Network algorithm. Neural Network algorithm can be divided into three categories. In the first one, a Back Propagation-based NN algorithm is well-known to gradient descent method. In the second scheme, a Extended Kalman Filter-based NN algorithm has just the time varying learning rate. In the last scheme, a Recursive Least Square-based NN algorithm is faster and more stable than the classical back-propagation algorithm for training multilayer perceptrons. The number of iterations required to converge and the mean-squared error between the desired and actual outputs is compared with respect to each method. The theoretical analysis and experimental results are discussed.

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Estimating a Consolidation Behavior of Clay Using Artificial Neural Network (인공신경망을 이용한 압밀거동 예측)

  • Park, Hyung-Gyu;Kang, Myung-Chan;Lee, Song
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.673-680
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    • 2000
  • Artificial neural networks are efficient computing techniques that are widely used to solve complex problems in many fields. In this study, a back-propagation neural network model for estimating a consolidation behavior of clay from soil parameter, site investigation data and the first settlement curve is proposed. The training and testing of the network were based on a database of 63 settlement curve from two different sites. Five different network models were used to study the ability of the neural network to predict the desired output to increasing degree of accuracy. The study showed that the neural network model predicted a consolidation behavior of clay reasonably well.

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Adult Image Blocking using Feature Extraction based BP Neural Network (특징 추출 기반 BP 신경망을 이용한 성인 영상 차단)

  • Kim, Jong-Il;Lee, Jung-Suk;Ahn, Hyun-Sik;Jeong, Gu-Min;Kim, Do-Hyun
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.349-351
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    • 2005
  • 현재 다양한 인터넷 콘텐츠들에 의해 많은 정보가 공유되고 있으며, 유익한 정보들과 더불어 성인물과 같은 유해한 정보들이 있다. 이로 인하여 여러 문제점들이 야기되고 있으며, 이를 해결하기 위해 다양한 방법들이 제안되고 있다. 그 중에서 성인 영상 차단을 위한 연구도 많이 행해지고 있으며 주로 색상을 이용한 방법을 사용하고 있다. 그러나 살색과 유사한 영상이나 노출이 심한 영상에는 성인 영상 검출의 신뢰성이 떨어지는 단점을 갖는다. 본 논문에서는 이런 문제점을 해결하기 위해 새로운 성인 영상 차단 방법을 제안한다. 기존의 제안된 살색 검출을 이용한 방법을 기반으로 성인 영상물로 판정될 수 있는 신체 부위를 검출함으로써 강인한 성인 영상 차단을 한다. 신체 부위에 대한 판별을 위해 여러 기저 영상에서 특징 벡터를 추출하고. 이 벡터를 Back Propagation(BP) 신경망의 데이터로 이용하여 학습한다. 제안한 성인 영상 차단 방법의 성능을 여러 장의 살색과 유사한 색상의 물체 영상과 노출이 심한 영상, 성인 영상을 이용한 종합적인 실험 결과인 성인 영상 검출률을 통해 증명한다.

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