• Title/Summary/Keyword: Latent space

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Semi-supervised Multi-view Manifold Discriminant Intact Space Learning

  • Han, Lu;Wu, Fei;Jing, Xiao-Yuan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권9호
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    • pp.4317-4335
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    • 2018
  • Semi-supervised multi-view latent space learning is gaining considerable popularity recently in many machine learning applications due to the high cost and difficulty to obtain the large amount of label information of data. Although some semi-supervised multi-view latent space learning methods have been presented, there is still much space for improvement: 1) How to learn latent discriminant intact feature representations by employing data of multiple views; 2) How to exploit the manifold structure of both labeled and unlabeled point in the learned latent intact space effectively. To address the above issues, we propose an approach called semi-supervised multi-view manifold discriminant intact space learning ($SM^2DIS$) for image classification in this paper. $SM^2DIS$ aims to seek a manifold discriminant intact space for data of different views by making use of both the discriminant information of labeled data and the manifold structure of both labeled and unlabeled data. Experimental results on MNIST, COIL-20, Multi-PIE, and Caltech-101 databases demonstrate the effectiveness and robustness of our proposed approach.

A New Method to Retrieve Sensible Heat and Latent Heat Fluxes from the Remote Sensing Data

  • Liou Yuei-An;Chen Yi-Ying;Chien Tzu-Chieh;Chang Tzu-Yin
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.415-417
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    • 2005
  • In order to retrieve the latent and sensible heat fluxes, high-resolution airborne imageries with visible, near infrared, and thermal infrared bands and ground-base meteorology measurements are utilized in this paper. The retrieval scheme is based on the balance of surface energy budget and momentum equations. There are three basic surface parameters including surface albedo $(\alpha)$, normalized difference vegetation index (NOVI) and surface kinetic temperature (TO). Lowtran 7 code is used to correct the atmosphere effect. The imageries were taken on 28 April and 5 May 2003. From the scattering plot of data set, we observed the extreme dry and wet pixels to derive the fitting of dry and wet controlled lines, respectively. Then the sensible heat and latent heat fluxes are derived from through a partitioning factor A. The retrieved latent and sensible heat fluxes are compared with in situ measurements, including eddy correlation and porometer measurements. It is shown that the retrieved fluxes from our scheme match with the measurements better than those derived from the S-SEBI model.

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다중 레이블 분류의 정확도 향상을 위한 스킵 연결 오토인코더 기반 레이블 임베딩 방법론 (Label Embedding for Improving Classification Accuracy UsingAutoEncoderwithSkip-Connections)

  • 김무성;김남규
    • 지능정보연구
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    • 제27권3호
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    • pp.175-197
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    • 2021
  • 최근 딥 러닝 기술의 발전으로 뉴스, 블로그 등 다양한 문서에 포함된 텍스트 분석에 딥 러닝 기술을 활용하는 연구가 활발하게 수행되고 있다. 다양한 텍스트 분석 응용 가운데, 텍스트 분류는 학계와 업계에서 가장 많이 활용되는 대표적인 기술이다. 텍스트 분류의 활용 예로는 정답 레이블이 하나만 존재하는 이진 클래스 분류와 다중 클래스 분류, 그리고 정답 레이블이 여러 개 존재하는 다중 레이블 분류 등이 있다. 특히, 다중 레이블 분류는 여러 개의 정답 레이블이 존재한다는 특성 때문에 일반적인 분류와는 상이한 학습 방법이 요구된다. 또한, 다중 레이블 분류 문제는 레이블과 클래스의 개수가 증가할수록 예측의 난이도가 상승한다는 측면에서 데이터 과학 분야의 난제로 여겨지고 있다. 따라서 이를 해결하기 위해 다수의 레이블을 압축한 후 압축된 레이블을 예측하고, 예측된 압축 레이블을 원래 레이블로 복원하는 레이블 임베딩이 많이 활용되고 있다. 대표적으로 딥 러닝 모델인 오토인코더 기반 레이블 임베딩이 이러한 목적으로 사용되고 있지만, 이러한 기법은 클래스의 수가 무수히 많은 고차원 레이블 공간을 저차원 잠재 레이블 공간으로 압축할 때 많은 정보 손실을 야기한다는 한계가 있다. 이에 본 연구에서는 오토인코더의 인코더와 디코더 각각에 스킵 연결을 추가하여, 고차원 레이블 공간의 압축 과정에서 정보 손실을 최소화할 수 있는 레이블 임베딩 방법을 제안한다. 또한 학술연구정보서비스인 'RISS'에서 수집한 학술논문 4,675건에 대해 각 논문의 초록으로부터 해당 논문의 다중 키워드를 예측하는 실험을 수행한 결과, 제안 방법론이 기존의 일반 오토인코더 기반 레이블 임베딩 기법에 비해 정확도, 정밀도, 재현율, 그리고 F1 점수 등 모든 측면에서 우수한 성능을 나타냄을 확인하였다.

미스 반 데어 로에 건축공간의 잠복성 (Latency in the Architectural Space of Mies van der Rohe)

  • 정만영;최은국
    • 건축역사연구
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    • 제15권3호
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    • pp.119-135
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    • 2006
  • This study based on the hypothesis which the spatial qualities in the Mies's early works are not extinct but potentially immanent in his latter works. In Mies's early works, destruction of outline, centrifugal extension of fluid space, and asymmetry are distinctly showed. These qualities probably revert to the indefiniteness of space. In Mies's latter works, however, these dynamic qualities are disappeared. Geometrically precise outline and exact grid structure represent universal space derived from zero-degree pure box. These qualities probably revert to tile definiteness of space, characterized by the unmovable emptiness. Although Mies works vary in external form, his expression technique of space reveals continually both the qualify of definitive and indefinitive space. For example, in the Museum for a Small City(1942) unbuilt project. elements defined by the perspective are fixed and static, but elements defined by the collages are floated and dynamic. The former reigns over the realized buildings of Mies, while the latter seems to be latent in terms of Schein which transcends reality. If we can penetrate this point, it's possible to read the other side of Mies' architectural works, distinct from both the canonized interpretation and the excessive criticism. Point is that later works of Mies must be understood as interplay of universal space appeared as phenomenon and flowing elements latent in. Architectural space of Mies keeps a distance with actual space through latent manner of being while preserves the empirical actuality It provides us with an occasion which appears only in an instant, in which even the ordinary things reveal its poetics.

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APPLICATION OF REMOTE SENSING IMAGERY ON THE ESTIMATE OF EVAPOTRANSPIRATION OVER PADDY FIELD

  • Chang, Tzu-Yin;Chien, Tzu-Chieh;Liou, Yuei-An
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.752-755
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    • 2006
  • Evaportranspiration is an important factor in hydrology cycle. Traditionally, it is measured by using basin or empirical formula with meteorology data, while it does not represent the evaportranspiration over a regional area. With the advent of improved remote sensing technology, it becomes a surface parameter of research interest in the field of remote sensing. Airborne and satellite imagery are utilized in this study. The high resolution airborne images include visible, near infrared, and thermal infrared bands and the satellite images are acquired by MODIS. Surface heat fluxes such as latent heat flux and sensible heat flux are estimate by using airborne and satellite images with surface meteorological measurements. We develop a new method to estimate the evaportranspiration over the rice paddy. The surface heat fluxes are initialized with a surface energy balance concept and iterated for convergent solution with atmospheric correct functions associated with aerodynamic resistance of heat transport. Furthermore, we redistribute the total net energy into sensible heat and latent heat fluxes. The result reveals that radiation and evaporation controlled extremes can be properly decided with both airborne and satellite images. The correlation coefficient of latent heat flux and sensible heat flux with corresponding in situ observations are 0.66 and 0.76, respectively. The relative root mean squared errors (RMSEs) for latent heat flux and sensible heat flux are 97.81 $(W/m^2)$ and 124.33 $(W/m^2)$, respectively. It is also shown that the newly developed retrieval scheme performs well when it is tested by using MODIS date.

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분석변수들의 잠재공간 표현 (Representing variables in the latent space)

  • 허명회
    • 응용통계연구
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    • 제30권4호
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    • pp.555-566
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    • 2017
  • 다변량 자료에서 변수 수 p가 큰 경우 주성분분석 등 통상적인 차원축소는 효과적이지 못할 수 있다. 효과적인 시각화가 되려면 축소공간의 차원이 2-3 정도이어야 하는데, 관측개체의 잠재적 차원이 이보다 훨씬 큰 경우가 있기 때문이다. 이 논문은 분석변수들을 다수의 잠재 차원에 분할하여 차원축소적 방법으로 탐색하고 부분들의 유기적 관계를 시각화하는 이단계 작업을 제안한다. 분석변수들을 잠재 차원에 분할하는 "잠재변인 변수군집화" 방법으로는 R팩키지 ClustOfVar를 쓰고 개별 변수군집의 시각화를 위해서 주성분분석 행렬도(biplot)를, 개별 변수군집과 외부 잠재변인 또는 외적 변수 간 관계의 시각화를 위해서는 추가변수 끼워넣기(embedding supplementary variables) 기법을 활용한다.

USING MODIS DATA TO ESTIMATE THE SURFACE HEAT FLUXES OVER TAIWAN'S CHIAYI PLAIN

  • Ho, Han-Chieh;Liou, Yuei-An;Wang, Chuan-Sheng
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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    • pp.317-319
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    • 2008
  • Traditionally, it is measured by using basin or empirical formula with meteorology data, while it does not represent the evaportransporation over a regional area. With the advent of improved remote sensing technology, it becomes feasible to assess the ET over a regional scale. Firstly, the IMAGINE ATCOR atmospheric module is used to preprocess for the MODIS imagery. Then MODIS satellite images which have been corrected by radiation and geometry in conjunction with the in-situ surface meteorological measurement are used to estimate the surface heat fluxes such as soil heat flux, sensible heat flux, and latent heat flux. In addition, the correlation coefficient between the derived latent heat and the in-situ measurement is found to be over 0.76. In the future, we will continue to monitor the surface heat fluxes of paddy rice field in Chiayi area.

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음성인식을 위한 변환 공간 모델에 근거한 순차 적응기법 (Sequential Adaptation Algorithm Based on Transformation Space Model for Speech Recognition)

  • 김동국;장준혁;김남수
    • 음성과학
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    • 제11권4호
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    • pp.75-88
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    • 2004
  • In this paper, we propose a new approach to sequential linear regression adaptation of continuous density hidden Markov models (CDHMMs) based on transformation space model (TSM). The proposed TSM which characterizes the a priori knowledge of the training speakers associated with maximum likelihood linear regression (MLLR) matrix parameters is effectively described in terms of the latent variable models. The TSM provides various sources of information such as the correlation information, the prior distribution, and the prior knowledge of the regression parameters that are very useful for rapid adaptation. The quasi-Bayes (QB) estimation algorithm is formulated to incrementally update the hyperparameters of the TSM and regression matrices simultaneously. Experimental results showed that the proposed TSM approach is better than that of the conventional quasi-Bayes linear regression (QBLR) algorithm for a small amount of adaptation data.

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Finding the best suited autoencoder for reducing model complexity

  • Ngoc, Kien Mai;Hwang, Myunggwon
    • 스마트미디어저널
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    • 제10권3호
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    • pp.9-22
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    • 2021
  • Basically, machine learning models use input data to produce results. Sometimes, the input data is too complicated for the models to learn useful patterns. Therefore, feature engineering is a crucial data preprocessing step for constructing a proper feature set to improve the performance of such models. One of the most efficient methods for automating feature engineering is the autoencoder, which transforms the data from its original space into a latent space. However certain factors, including the datasets, the machine learning models, and the number of dimensions of the latent space (denoted by k), should be carefully considered when using the autoencoder. In this study, we design a framework to compare two data preprocessing approaches: with and without autoencoder and to observe the impact of these factors on autoencoder. We then conduct experiments using autoencoders with classifiers on popular datasets. The empirical results provide a perspective regarding the best suited autoencoder for these factors.

EVALUATION OF SURFACE HEAT FLUXES FOR DIFFERENT LAND COVER IN HEAT ISLAND EFFECT

  • Chang, Tzu-Yin;Liao, Lu-Wei;Liou, Yuei-An
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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    • pp.68-71
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    • 2008
  • Our goal is to obtain a better scientific understanding how to define the nature and role of remotely sensed land surface parameters and energy fluxes in the heat island phenomena, and local and regional weather and climate. By using the MODIS visible and thermal imagery data and analyzing the surface energy flux images associated with the change of the landcover and landuse in study area, we will estimate and present how significant is the magnitude of the heat island heat effect and its relation with the surface parameters and the energy fluxes in Taiwan. To achieve our objective, we used the energy budget components such as net radiation, soil heat flux, sensible heat flux, and latent heat flux in the study area of interest derived form remotely sensed data to understand the island heat effect. The result shows that the water is the most important component to decrease the temperature, and the more the consumed net radiation to latent heat, the lower urban surface temperature.

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