• Title/Summary/Keyword: 부분최소법

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Direct Inversion of Seabed Properties from a Wideband Signal using Genetic Algorithms (유전자 알고리즘을 사용한 광대역 신호로부터 직접적인 해저 지질 특성치 역산)

  • 박철수;성우제
    • The Journal of the Acoustical Society of Korea
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    • v.17 no.7
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    • pp.36-41
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    • 1998
  • 본 논문에서는 부분파수적분법과 유전자알고리즘기법의 조합을 통한 광대역 신호로 부터 직접적인 해저지질특성치의 역산기법을 제시하였다. 광대역주파수신호의 시간영역 모 의는 부분파수적분법을 사용하여 계산시간을 단축하였고, 다수의 국부최소점이 존재하는 역 산문제에 유전자알고리즘기법을 적용한 전역되적점에 대한 탐색을 수행하였다. 본 방법을 사용하여 해저퇴적층의 지질특성 요소에 대한 역산을 수행하였다.

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An Efficient Method for Real-Time Broken Lane Tracking Using PHT and Least-Square Method (PHT와 최소자승법을 이용한 효율적인 실시간 점선차선 추적)

  • Xu, Sudan;Lee, Chang-Woo
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.6
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    • pp.619-623
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    • 2008
  • A lane detection system is one of the major components of intelligent vehicle systems. Difficulties in lane detection mainly come from not only various weather conditions but also a variety of special environment. This paper describes a simple and stable method for the broken lane tracking in various environments. Probabilistic Hough Transform (PHT) and the Least-square method (LSM) are used to track and correct the lane orientation. For the efficiency of the proposed method, two regions of interest (ROIs) are placed in the lower part of each image, where lane marking areas usually appear with less intervention in our system view. By testing in both a set of static images and video sequences, the experiments showed that the proposed approach yielded robust and reliable results.

Type I projection sum of squares by weighted least squares (가중최소제곱법에 의한 제1종 사영제곱합)

  • Choi, Jaesung
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.2
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    • pp.423-429
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    • 2014
  • This paper discusses a method for getting Type I sums of squares by projections under a two-way fixed-effects model when variances of errors are not equal. The method of weighted least squares is used to estimate the parameters of the assumed model. The model is fitted to the data in a sequential manner by using the model comparison technique. The vector space generated by the model matrix can be composed of orthogonal vector subspaces spanned by submatrices consisting of column vectors related to the parameters. It is discussed how to get the Type I sums of squares by using the projections into the orthogonal vector subspaces.

Harmonic Injection Method for Increasing DC-link Voltage in Drive Systems with Single-Phase Diode Rectifier and Small DC-link Capacitor (단상 다이오드 정류기와 소용량 직류단 캐패시터를 가지는 전동기 구동 시스템에서 직류단 전압을 높이기 위한 고조파 주입법)

  • Chae, Young-Ho;Ha, Jung-Ik
    • Proceedings of the KIPE Conference
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    • 2015.11a
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    • pp.65-66
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    • 2015
  • 본 논문에서는 단상 다이오드 정류기와 소용량 직류단 캐패시터를 가지는 전동기 구동 시스템에서 계통 전류에 최소 고조파 전류 주입을 통하여 직류단 전압을 높이는 방법을 제안한다. 소용량 직류단 캐패시터를 가지는 전동기 구동 시스템은 직류단전압이 맥동하게 되는데 직류단 전압이 낮은 부분에서는 과도한 약자속 전류가 필요하게 된다. 기존의 연구에서는 직류단 전압을 확보하기 위해 직류단 최소 전압을 설정하는 방법이 제안되었다. 하지만 계통 전류의 고조파 규정 때문에 직류단 최소 전압을 높이는 것은 한계가 있다. 제안된 방법에서는 계통 전류에 고조파를 주입함으로써 기존의 한계보다 더 높은 직류단 최소 전압을 가지면서도 계통 전류의 고조파 규정을 만족시킬 수 있도록 한다. 제안된 방법은 시뮬레이션을 통해 그 타당성을 검증한다.

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Estimation of VOCs Affecting a Used Car Air Conditioning Smell via PLSR (부분최소자승법을 이용한 중고차 에어컨냄새 원인물질 추정)

  • You, Hanmin;Lee, Taehee;Sung, Kiwoo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.6
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    • pp.175-182
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    • 2013
  • Lately, customers think highly of the emotional satisfaction and as a result, issues on odor are matters of concern. The cases are odor of interior material and air-conditioner of vehicles. In particualar, with respect to the odor of air-conditioner, customers strongly claimed defects with provocative comments : "It smells like something rotten," "It smells like a foot odor," "It stinks like a rag." Generally, it is known that mold of evaporator core in the air-conditioning system decays and this produce VOCs which causes the odor to occur. In this study, partial least squares regression model is applied to predict the strength of the odor and select of important VOCs which affect car air conditioning smell. The PLS method is basically a particular multilinear regression algorithm which can handle correlated inputs and limited data. The number of latent variable is determined by the point which is stabilized mean absolute deviations of VOCs data. Also multiple linear regression is carried out to confirm the validity of PLS method.

Reverse Filtering Method by Neural Network (신경회로망에 의한 역 필터링 기법)

  • Choi, Jae-seung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.695-698
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    • 2009
  • 본 논문에서는 음원으로부터 나온 음과 동일한 음을 들을 수 있는 시스템을 구축하는 것을 목적으로 하여 이 두 개의 음으로부터 전달되어온 음장의 상태를 구하여 이 역 필터를 구성하는 방법을 연구한다. 본 논문에서는 최소 2승 평균법(Least Mean Square, LMS)을 사용하여 FIR 필터(Finite Impulse Response)의 계수를 계산하여 이를 갱신함으로써 역 필터법을 구축하는 방법을 사용한다. 또한 이 방법과는 별도로 LMS법의 부분을 신경회로망에 대처하는 알고리즘을 제안하였다. 시뮬레이션 실험으로부터 상당히 간단한 파형에 비선형인 왜곡이 있는 것을 본 논문에서 제안한 신경회로망에 의한 학습 가능한 것을 확인하였다.

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Chlorophyll-a Forcasting using PLS Based c-Fuzzy Model Tree (PLS기반 c-퍼지 모델트리를 이용한 클로로필-a 농도 예측)

  • Lee, Dae-Jong;Park, Sang-Young;Jung, Nahm-Chung;Lee, Hye-Keun;Park, Jin-Il;Chun, Meung-Geun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.16 no.6
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    • pp.777-784
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    • 2006
  • This paper proposes a c-fuzzy model tree using partial least square method to predict the Chlorophyll-a concentration in each zone. First, cluster centers are calculated by fuzzy clustering method using all input and output attributes. And then, each internal node is produced according to fuzzy membership values between centers and input attributes. Linear models are constructed by partial least square method considering input-output pairs remained in each internal node. The expansion of internal node is determined by comparing errors calculated in parent node with ones in child node, respectively. On the other hands, prediction is performed with a linear model haying the highest fuzzy membership value between input attributes and cluster centers in leaf nodes. To show the effectiveness of the proposed method, we have applied our method to water quality data set measured at several stations. Under various experiments, our proposed method shows better performance than conventional least square based model tree method.

Analysis of Carbonization Behavior of Hydrochar Produced by Hydrothermal Carbonization of Lignin and Development of a Prediction Model for Carbonization Degree Using Near-Infrared Spectroscopy (열수 탄화 공정을 거친 리그닌 하이드로차(hydrochar)의 탄화 거동 분석과 근적외선 분광법을 이용한 예측 모델 개발)

  • HWANG, Un Taek;BAE, Junsoo;LEE, Taekyeong;HWANG, Sung-Yun;KIM, Jong-Chan;PARK, Jinseok;CHOI, In-Gyu;KWAK, Hyo Won;HWANG, Sung-Wook;YEO, Hwanmyeong
    • Journal of the Korean Wood Science and Technology
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    • v.49 no.3
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    • pp.213-225
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    • 2021
  • In this paper, we investigated the carbonization characteristics of lignin hydrochar prepared by hydrothermal carbonization and established a model for predicting the carbonization degree using near-infrared spectroscopy and partial least squares regression. The carbon content of the hydrothermally carbonized lignin at the temperature of 200 ℃ was higher by approximately 3 wt% than that of the untreated sample, and the carbon content tended to gradually increase as the heating time increased. Hydrothermal carbonization made lignin more carbon-intensive and more homogeneous by eliminating the microparticles. The discriminant and predictive models using near-infrared spectroscopy and partial least squares regression approppriately determined whether hydrothermal carbonization has been applied and predicted the carbon content of hydrothermal carbonized lignin with high accuracy. In this study, we confirmed that we can quickly and nondestructively predict the carbonization characteristics of lignin hydrochar manufactured by hydrothermal carbonization using a partial least squares regression model combined with near-infrared spectroscopy.

Development of an On-line Measurement Method for Clean Biofuel Based on Near Infrared Spectroscopy and Chemometrics (근적외선 분광학과 화학계량학에 기반한 청정 바이오연료 실시간 품질 측정 기술 개발)

  • Cho, Hyeong-Su;Ryu, Jun-Hyung;Liu, J. Jay
    • Clean Technology
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    • v.17 no.3
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    • pp.215-224
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    • 2011
  • It is an important issue to develop quality assessing system for biofuel for the purpose of accelerating the mass production of biofuel. It is particularly challenging to conduct testing method in the mass production of bioethanol while meeting quality specifications such as ASTM (American Society for Testing & Materials) D4806-10. In order to address this challenge, this paper proposes on-line spectroscopic quality assesment system based on Near Infrared spectrum and Partial Least Squares method in Chemometrics. As a result of testing a number of preprocessing methods and Partial Least Squares, it was found out that Savitzky-Golay method showed the best performance in terms of spectrum correction, noise reduction, and model maintenance. The proposed system allows us to assess multiple quality components continuously using spectroscopic facilities with the cheap cost. Since the value of R2 is more than 0.99, it is possible to replace the laboratory analysis.