• Title/Summary/Keyword: Latent class classification

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Two-stage Deep Learning Model with LSTM-based Autoencoder and CNN for Crop Classification Using Multi-temporal Remote Sensing Images

  • Kwak, Geun-Ho;Park, No-Wook
    • Korean Journal of Remote Sensing
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    • v.37 no.4
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    • pp.719-731
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    • 2021
  • This study proposes a two-stage hybrid classification model for crop classification using multi-temporal remote sensing images; the model combines feature embedding by using an autoencoder (AE) with a convolutional neural network (CNN) classifier to fully utilize features including informative temporal and spatial signatures. Long short-term memory (LSTM)-based AE (LAE) is fine-tuned using class label information to extract latent features that contain less noise and useful temporal signatures. The CNN classifier is then applied to effectively account for the spatial characteristics of the extracted latent features. A crop classification experiment with multi-temporal unmanned aerial vehicle images is conducted to illustrate the potential application of the proposed hybrid model. The classification performance of the proposed model is compared with various combinations of conventional deep learning models (CNN, LSTM, and convolutional LSTM) and different inputs (original multi-temporal images and features from stacked AE). From the crop classification experiment, the best classification accuracy was achieved by the proposed model that utilized the latent features by fine-tuned LAE as input for the CNN classifier. The latent features that contain useful temporal signatures and are less noisy could increase the class separability between crops with similar spectral signatures, thereby leading to superior classification accuracy. The experimental results demonstrate the importance of effective feature extraction and the potential of the proposed classification model for crop classification using multi-temporal remote sensing images.

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

  • Kim, Museong;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.175-197
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    • 2021
  • Recently, with the development of deep learning technology, research on unstructured data analysis is being actively conducted, and it is showing remarkable results in various fields such as classification, summary, and generation. Among various text analysis fields, text classification is the most widely used technology in academia and industry. Text classification includes binary class classification with one label among two classes, multi-class classification with one label among several classes, and multi-label classification with multiple labels among several classes. In particular, multi-label classification requires a different training method from binary class classification and multi-class classification because of the characteristic of having multiple labels. In addition, since the number of labels to be predicted increases as the number of labels and classes increases, there is a limitation in that performance improvement is difficult due to an increase in prediction difficulty. To overcome these limitations, (i) compressing the initially given high-dimensional label space into a low-dimensional latent label space, (ii) after performing training to predict the compressed label, (iii) restoring the predicted label to the high-dimensional original label space, research on label embedding is being actively conducted. Typical label embedding techniques include Principal Label Space Transformation (PLST), Multi-Label Classification via Boolean Matrix Decomposition (MLC-BMaD), and Bayesian Multi-Label Compressed Sensing (BML-CS). However, since these techniques consider only the linear relationship between labels or compress the labels by random transformation, it is difficult to understand the non-linear relationship between labels, so there is a limitation in that it is not possible to create a latent label space sufficiently containing the information of the original label. Recently, there have been increasing attempts to improve performance by applying deep learning technology to label embedding. Label embedding using an autoencoder, a deep learning model that is effective for data compression and restoration, is representative. However, the traditional autoencoder-based label embedding has a limitation in that a large amount of information loss occurs when compressing a high-dimensional label space having a myriad of classes into a low-dimensional latent label space. This can be found in the gradient loss problem that occurs in the backpropagation process of learning. To solve this problem, skip connection was devised, and by adding the input of the layer to the output to prevent gradient loss during backpropagation, efficient learning is possible even when the layer is deep. Skip connection is mainly used for image feature extraction in convolutional neural networks, but studies using skip connection in autoencoder or label embedding process are still lacking. Therefore, in this study, we propose an autoencoder-based label embedding methodology in which skip connections are added to each of the encoder and decoder to form a low-dimensional latent label space that reflects the information of the high-dimensional label space well. In addition, the proposed methodology was applied to actual paper keywords to derive the high-dimensional keyword label space and the low-dimensional latent label space. Using this, we conducted an experiment to predict the compressed keyword vector existing in the latent label space from the paper abstract and to evaluate the multi-label classification by restoring the predicted keyword vector back to the original label space. As a result, the accuracy, precision, recall, and F1 score used as performance indicators showed far superior performance in multi-label classification based on the proposed methodology compared to traditional multi-label classification methods. This can be seen that the low-dimensional latent label space derived through the proposed methodology well reflected the information of the high-dimensional label space, which ultimately led to the improvement of the performance of the multi-label classification itself. In addition, the utility of the proposed methodology was identified by comparing the performance of the proposed methodology according to the domain characteristics and the number of dimensions of the latent label space.

Classification of latent classes and analysis of influencing factors on longitudinal changes in middle school students' mathematics interest and achievement: Using multivariate growth mixture model (중학생들의 수학 흥미와 성취도의 종단적 변화에 따른 잠재집단 분류 및 영향요인 탐색: 다변량 성장혼합모형을 이용하여)

  • Rae Yeong Kim;Sooyun Han
    • The Mathematical Education
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    • v.63 no.1
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    • pp.19-33
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    • 2024
  • This study investigates longitudinal patterns in middle school students' mathematics interest and achievement using panel data from the 4th to 6th year of the Gyeonggi Education Panel Study. Results from the multivariate growth mixture model confirmed the existence of heterogeneous characteristics in the longitudinal trajectory of students' mathematics interest and achievement. Students were classified into four latent classes: a low-level class with weak interest and achievement, a high-level class with strong interest and achievement, a middlelevel-increasing class where interest and achievement rise with grade, and a middle-level-decreasing class where interest and achievement decline with grade. Each class exhibited distinct patterns in the change of interest and achievement. Moreover, an examination of the correlation between intercepts and slopes in the multivariate growth mixture model reveals a positive association between interest and achievement with respect to their initial values and growth rates. We further explore predictive variables influencing latent class assignment. The results indicated that students' educational ambition and time spent on private education positively affect mathematics interest and achievement, and the influence of prior learning varies based on its intensity. The perceived instruction method significantly impacts latent class assignment: teacher-centered instruction increases the likelihood of belonging to higher-level classes, while learner-centered instruction increases the likelihood of belonging to lower-level classes. This study has significant implications as it presents a new method for analyzing the longitudinal patterns of students' characteristics in mathematics education through the application of the multivariate growth mixture model.

Classifying Latent Profiles in the Exposure to Hazard Factors of Salaried Employees (잠재프로파일분석을 통한 임금근로자의 위험요인 노출 유형분류 및 영향요인 검증)

  • Lee, Eunjin;Hong, Sehee
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.31 no.3
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    • pp.237-254
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    • 2021
  • Objectives: This study aims to classify the latent profiles in the exposure to hazard factors of salaried employees and test the determinants. Methods: Latent profile analysis(LPA) was conducted using data from the fifth Korean Working Conditions Survey(KWCS). 30,050 of salaried employees were the subjects of this study. After classifying the employees, multinomial logistic regression was used to test the determinants. Results: Salaried employees were classified with three latent profiles based on the exposure to the hazard factors. Employees included in class 1(32.8%) tend to experience low level of physical hazard factors, moderate level of psychological hazard factors, and high level of office work hazard factors. Employees included in class 2(61.8%) tend to be exposed to the moderate to high level of physical hazard factors, moderate to low level of psychological hazard factors, and low level of office work hazard factors. Employees included in class 3(5.4%) tend to experience high level of psychological and physical hazard factors, and moderate level of office work hazard factors. After classification, the demographic, health-, and employment-related variables were tested. Conclusions: This study clarified the features of each class, and proved that employees in class 3 are quite hazardous in that they are exposed to physical and psychological hazard factors much more frequently than other employees. Thus, this study can be used in predicting the high-risk employees and taking preemptive measures for preventing industrial accidents.

New Inference for a Multiclass Gaussian Process Classification Model using a Variational Bayesian EM Algorithm and Laplace Approximation

  • Cho, Wanhyun;Kim, Sangkyoon;Park, Soonyoung
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.4
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    • pp.202-208
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    • 2015
  • In this study, we propose a new inference algorithm for a multiclass Gaussian process classification model using a variational EM framework and the Laplace approximation (LA) technique. This is performed in two steps, called expectation and maximization. First, in the expectation step (E-step), using Bayes' theorem and the LA technique, we derive the approximate posterior distribution of the latent function, indicating the possibility that each observation belongs to a certain class in the Gaussian process classification model. In the maximization step, we compute the maximum likelihood estimators for hyper-parameters of a covariance matrix necessary to define the prior distribution of the latent function by using the posterior distribution derived in the E-step. These steps iteratively repeat until a convergence condition is satisfied. Moreover, we conducted the experiments by using synthetic data and Iris data in order to verify the performance of the proposed algorithm. Experimental results reveal that the proposed algorithm shows good performance on these datasets.

Career Developmental Characteristic in Latent Classes based on Belief in a Just World and Social class of Middle-aged adult (중·장년 성인의 정당한 세상에 대한 믿음과 사회계층에 따른 잠재집단의 진로발달 특성)

  • Kim, Dohyun;Jang, Jinyi
    • 한국노년학
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    • v.41 no.4
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    • pp.567-586
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    • 2021
  • This study explored what latent classes appear according to the combination of Belief in a Just World (BJW) and social class of middle-aged adults, and examined whether there are differences in career transiton, perceiving a calling, and working as meaning in each class and what characteristics they have. 224 middle-aged people who experienced turnover through online and offline were surveyed and analyzed by Latent Profile Analysis. The participants were divided into 5 latent classes such as; 'Relative self-satisfaction', 'Social contentment', 'Relative deprived', 'Fairness trust' and 'Fairness distrust'. According to the results of MANOVA analysis to figure out if there are differences in career transitions, perceiving a calling, and working as meaning depending on latent classes, significant differences were appeared among latent classes. Finally, multinominal logistic regression analysis was conducted to examine whether demographic characteristics and 'decent work' affect the latent group classification. As a result, the more 'decent work', the higher the probability of belonging to the class with high BJW and social class. On the basis of the results of this study, the implications on the case conceptualization and counseling strategy for adults focusing on BJW and Social class in adults and future research were discussed.

Forensic Classification of Latent Fingerprints Applying Laser-induced Plasma Spectroscopy Combined with Chemometric Methods (케모메트릭 방법과 결합된 레이저 유도 플라즈마 분광법을 적용한 유류 지문의 법의학적 분류 연구)

  • Yang, Jun-Ho;Yoh, Jai-Ick
    • Korean Journal of Optics and Photonics
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    • v.31 no.3
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    • pp.125-133
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    • 2020
  • An innovative method for separating overlapping latent fingerprints, using laser-induced plasma spectroscopy (LIPS) combined with multivariate analysis, is reported in the current study. LIPS provides the capabilities of real-time analysis and high-speed scanning, as well as data regarding the chemical components of overlapping fingerprints. These spectra provide valuable chemical information for the forensic classification and reconstruction of overlapping latent fingerprints, by applying appropriate multivariate analysis. This study utilizes principal-component analysis (PCA) and partial-least-squares (PLS) techniques for the basis classification of four types of fingerprints from the LIPS spectra. The proposed method is successfully demonstrated through a classification example of four distinct latent fingerprints, using discrimination such as soft independent modeling of class analogy (SIMCA) and partial-least-squares discriminant analysis (PLS-DA). This demonstration develops an accuracy of more than 85% and is proven to be sufficiently robust. In addition, by laser-scanning analysis at a spatial interval of 125 ㎛, the overlapping fingerprints were separated as two-dimensional forms.

A New Latent Class Model for Analysis of Purchasing and Browsing Histories on EC Sites

  • Goto, Masayuki;Mikawa, Kenta;Hirasawa, Shigeichi;Kobayashi, Manabu;Suko, Tota;Horii, Shunsuke
    • Industrial Engineering and Management Systems
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    • v.14 no.4
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    • pp.335-346
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    • 2015
  • The electronic commerce site (EC site) has become an important marketing channel where consumers can purchase many kinds of products; their access logs, including purchase records and browsing histories, are saved in the EC sites' databases. These log data can be utilized for the purpose of web marketing. The customers who purchase many product items are good customers, whereas the other customers, who do not purchase many items, must not be good customers even if they browse many items. If the attributes of good customers and those of other customers are clarified, such information is valuable as input for making a new marketing strategy. Regarding the product items, the characteristics of good items that are bought by many users are valuable information. It is necessary to construct a method to efficiently analyze such characteristics. This paper proposes a new latent class model to analyze both purchasing and browsing histories to make latent item and user clusters. By applying the proposal, an example of data analysis on an EC site is demonstrated. Through the clusters obtained by the proposed latent class model and the classification rule by the decision tree model, new findings are extracted from the data of purchasing and browsing histories.

Analysis of Student's Satisfaction Types of the Campus-Life and Affecting Factors using Latent Profile Analysis (잠재프로파일 분석을 이용한 대학생활 만족유형 분류 및 영향요인 분석)

  • Ryu, HoJun;Kil, HyeJi;Rah, Min-Joo
    • The Journal of the Korea Contents Association
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    • v.22 no.8
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    • pp.482-491
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    • 2022
  • The purpose of this study was to classify latent profiles based on satisfaction of student by the campus-life&educational-experiences and to identify factors affecting satisfaction according to each type. For this study, data from the survey of the A univ(1,952 data) were used. To analyze this, a latent profiles analysis was applied to identify subgroups, in which the students by the campus-life&educational-experiences satisfaction, and a multinomial logistic regression model was applied to verify factors affecting group classification. As a result of the analysis, first four groups were classified in the order of 'average·class·highest·relationship satisfaction type'. Second the factors affecting the classification into the remaining three types with 'the average satisfaction type' as a reference group were found to be significant influencing factors(gender, grade, admission process, GPA grade). Based on these results, this study suggested implications for planning and promoting student-tailored education and student support policies at the university level.

Analysis of the characteristics of medical service depending on the latent classification of medical information (의료정보 이용의 잠재적 유형에 따른 의료서비스 특성분석)

  • Ahn, Chang-Hee
    • Korea Journal of Hospital Management
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    • v.17 no.3
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    • pp.57-82
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    • 2012
  • The primary purpose of this study is to examine consumers'probing actions to see what information sources consumers search for medical information when there are diverse medical service information channels, and classify consumers by information source. Its secondary purpose is to understand trust of information and attitude toward information by consumer type, value of medical service, satisfaction with medical service, and word-of-mouth intention. This study will concretely identify information utilization patterns of medical consumers, and explain the unique characteristics and behavior of segmented types of medical consumers. The significance of this study lies in the search for ways to establish information channels trusted by consumers for building an efficient medical service market in the future. The results of this study show that consumers were classified by the latent class analysis(LCA) into 5 types: low-level information seekers, word-of-mouth information seekers, mass media information seekers, digital information seekers and diverse information seekers. The reliability of information sources by type of medical consumer was statistically significant, and in the analysis of differences in consumer attitude, there was a statistically significant difference in cognitive responses. The value of medical service was statistically significant in health recovery and medical service word-of-mouth intention.

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