• Title/Summary/Keyword: unlabeled documents

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Utilizing Unlabeled Documents in Automatic Classification with Inter-document Similarities (문헌간 유사도를 이용한 자동분류에서 미분류 문헌의 활용에 관한 연구)

  • Kim, Pan-Jun;Lee, Jae-Yun
    • Journal of the Korean Society for information Management
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    • v.24 no.1 s.63
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    • pp.251-271
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    • 2007
  • This paper studies the problem of classifying documents with labeled and unlabeled learning data, especially with regards to using document similarity features. The problem of using unlabeled data is practically important because in many information systems obtaining training labels is expensive, while large quantities of unlabeled documents are readily available. There are two steps In general semi-supervised learning algorithm. First, it trains a classifier using the available labeled documents, and classifies the unlabeled documents. Then, it trains a new classifier using all the training documents which were labeled either manually or automatically. We suggested two types of semi-supervised learning algorithm with regards to using document similarity features. The one is one step semi-supervised learning which is using unlabeled documents only to generate document similarity features. And the other is two step semi-supervised learning which is using unlabeled documents as learning examples as well as similarity features. Experimental results, obtained using support vector machines and naive Bayes classifier, show that we can get improved performance with small labeled and large unlabeled documents then the performance of supervised learning which uses labeled-only data. When considering the efficiency of a classifier system, the one step semi-supervised learning algorithm which is suggested in this study could be a good solution for improving classification performance with unlabeled documents.

A Study on Incremental Learning Model for Naive Bayes Text Classifier (Naive Bayes 문서 분류기를 위한 점진적 학습 모델 연구)

  • 김제욱;김한준;이상구
    • The Journal of Information Technology and Database
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    • v.8 no.1
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    • pp.95-104
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    • 2001
  • In the text classification domain, labeling the training documents is an expensive process because it requires human expertise and is a tedious, time-consuming task. Therefore, it is important to reduce the manual labeling of training documents while improving the text classifier. Selective sampling, a form of active learning, reduces the number of training documents that needs to be labeled by examining the unlabeled documents and selecting the most informative ones for manual labeling. We apply this methodology to Naive Bayes, a text classifier renowned as a successful method in text classification. One of the most important issues in selective sampling is to determine the criterion when selecting the training documents from the large pool of unlabeled documents. In this paper, we propose two measures that would determine this criterion : the Mean Absolute Deviation (MAD) and the entropy measure. The experimental results, using Renters 21578 corpus, show that this proposed learning method improves Naive Bayes text classifier more than the existing ones.

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Incremental Superised Learning based on SVM with Unlabeled Documents (레이블이 없는 문서를 이용한 SVM 기반의 점증적 지도학습)

  • 김수영;조성배
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.04b
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    • pp.301-303
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    • 2002
  • 컴퓨터가 널리 보급되고 인터넷이 발전함에 따라 수없이 많은 정보가 디지털 형태로 생산되고 있다. 이러한 정보를 사람이 일일이 가공하고 분류하기에는 한계가 있으므로 자동으로 문서를 분류하고자 하는 연구가 대두되었다. 문서를 자동으로 분류하기 위해 기계학습 방법이 많이 이용되고 있다. 기계학습방법을 이용한 문서분류가 좋은 성능을 내기 위해서는 충분한 양의 학습데이터가 필요하다. 학습데이터를 만들기 위해서는 사람이 일일이 분류해야 하므로, 비용이 많이 든다. 본 논문에서는 적은양의 labeled 데이터로부터 시작하여, 점증적으로 unlabeled 데이터를 학습에 참여시킴으로써, 문서분류의 성능을 높이고자 한다. 실험을 통해 Unlabeled 문서데이터를 사용한 것이 좋은 성능을 보였음을 알 수 있다.

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Automatic Text Categorization based on Semi-Supervised Learning (준지도 학습 기반의 자동 문서 범주화)

  • Ko, Young-Joong;Seo, Jung-Yun
    • Journal of KIISE:Software and Applications
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    • v.35 no.5
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    • pp.325-334
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    • 2008
  • The goal of text categorization is to classify documents into a certain number of pre-defined categories. The previous studies in this area have used a large number of labeled training documents for supervised learning. One problem is that it is difficult to create the labeled training documents. While it is easy to collect the unlabeled documents, it is not so easy to manually categorize them for creating training documents. In this paper, we propose a new text categorization method based on semi-supervised learning. The proposed method uses only unlabeled documents and keywords of each category, and it automatically constructs training data from them. Then a text classifier learns with them and classifies text documents. The proposed method shows a similar degree of performance, compared with the traditional supervised teaming methods. Therefore, this method can be used in the areas where low-cost text categorization is needed. It can also be used for creating labeled training documents.

A Text Categorization Method Improved by Removing Noisy Training Documents (오류 학습 문서 제거를 통한 문서 범주화 기법의 성능 향상)

  • Han, Hyoung-Dong;Ko, Young-Joong;Seo, Jung-Yun
    • Journal of KIISE:Software and Applications
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    • v.32 no.9
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    • pp.912-919
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    • 2005
  • When we apply binary classification to multi-class classification for text categorization, we use the One-Against-All method generally, However, this One-Against-All method has a problem. That is, documents of a negative set are not labeled by human. Thus, they can include many noisy documents in the training data. In this paper, we propose that the Sliding Window technique and the EM algorithm are applied to binary text classification for solving this problem. We here improve binary text classification through extracting noise documents from the training data by the Sliding Window technique and re-assigning categories of these documents using the EM algorithm.

An Automatic Classification System of Korean Documents Using Weight for Keywords of Document and Word Cluster (문서의 주제어별 가중치 부여와 단어 군집을 이용한 한국어 문서 자동 분류 시스템)

  • Hur, Jun-Hui;Choi, Jun-Hyeog;Lee, Jung-Hyun;Kim, Joong-Bae;Rim, Kee-Wook
    • The KIPS Transactions:PartB
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    • v.8B no.5
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    • pp.447-454
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    • 2001
  • The automatic document classification is a method that assigns unlabeled documents to the existing classes. The automatic document classification can be applied to a classification of news group articles, a classification of web documents, showing more precise results of Information Retrieval using a learning of users. In this paper, we use the weighted Bayesian classifier that weights with keywords of a document to improve the classification accuracy. If the system cant classify a document properly because of the lack of the number of words as the feature of a document, it uses relevance word cluster to supplement the feature of a document. The clusters are made by the automatic word clustering from the corpus. As the result, the proposed system outperformed existing classification system in the classification accuracy on Korean documents.

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Text Classification with Heterogeneous Data Using Multiple Self-Training Classifiers

  • William Xiu Shun Wong;Donghoon Lee;Namgyu Kim
    • Asia pacific journal of information systems
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    • v.29 no.4
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    • pp.789-816
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    • 2019
  • Text classification is a challenging task, especially when dealing with a huge amount of text data. The performance of a classification model can be varied depending on what type of words contained in the document corpus and what type of features generated for classification. Aside from proposing a new modified version of the existing algorithm or creating a new algorithm, we attempt to modify the use of data. The classifier performance is usually affected by the quality of learning data as the classifier is built based on these training data. We assume that the data from different domains might have different characteristics of noise, which can be utilized in the process of learning the classifier. Therefore, we attempt to enhance the robustness of the classifier by injecting the heterogeneous data artificially into the learning process in order to improve the classification accuracy. Semi-supervised approach was applied for utilizing the heterogeneous data in the process of learning the document classifier. However, the performance of document classifier might be degraded by the unlabeled data. Therefore, we further proposed an algorithm to extract only the documents that contribute to the accuracy improvement of the classifier.

Improving the Accuracy of Document Classification by Learning Heterogeneity (이질성 학습을 통한 문서 분류의 정확성 향상 기법)

  • Wong, William Xiu Shun;Hyun, Yoonjin;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.24 no.3
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    • pp.21-44
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    • 2018
  • In recent years, the rapid development of internet technology and the popularization of smart devices have resulted in massive amounts of text data. Those text data were produced and distributed through various media platforms such as World Wide Web, Internet news feeds, microblog, and social media. However, this enormous amount of easily obtained information is lack of organization. Therefore, this problem has raised the interest of many researchers in order to manage this huge amount of information. Further, this problem also required professionals that are capable of classifying relevant information and hence text classification is introduced. Text classification is a challenging task in modern data analysis, which it needs to assign a text document into one or more predefined categories or classes. In text classification field, there are different kinds of techniques available such as K-Nearest Neighbor, Naïve Bayes Algorithm, Support Vector Machine, Decision Tree, and Artificial Neural Network. However, while dealing with huge amount of text data, model performance and accuracy becomes a challenge. According to the type of words used in the corpus and type of features created for classification, the performance of a text classification model can be varied. Most of the attempts are been made based on proposing a new algorithm or modifying an existing algorithm. This kind of research can be said already reached their certain limitations for further improvements. In this study, aside from proposing a new algorithm or modifying the algorithm, we focus on searching a way to modify the use of data. It is widely known that classifier performance is influenced by the quality of training data upon which this classifier is built. The real world datasets in most of the time contain noise, or in other words noisy data, these can actually affect the decision made by the classifiers built from these data. In this study, we consider that the data from different domains, which is heterogeneous data might have the characteristics of noise which can be utilized in the classification process. In order to build the classifier, machine learning algorithm is performed based on the assumption that the characteristics of training data and target data are the same or very similar to each other. However, in the case of unstructured data such as text, the features are determined according to the vocabularies included in the document. If the viewpoints of the learning data and target data are different, the features may be appearing different between these two data. In this study, we attempt to improve the classification accuracy by strengthening the robustness of the document classifier through artificially injecting the noise into the process of constructing the document classifier. With data coming from various kind of sources, these data are likely formatted differently. These cause difficulties for traditional machine learning algorithms because they are not developed to recognize different type of data representation at one time and to put them together in same generalization. Therefore, in order to utilize heterogeneous data in the learning process of document classifier, we apply semi-supervised learning in our study. However, unlabeled data might have the possibility to degrade the performance of the document classifier. Therefore, we further proposed a method called Rule Selection-Based Ensemble Semi-Supervised Learning Algorithm (RSESLA) to select only the documents that contributing to the accuracy improvement of the classifier. RSESLA creates multiple views by manipulating the features using different types of classification models and different types of heterogeneous data. The most confident classification rules will be selected and applied for the final decision making. In this paper, three different types of real-world data sources were used, which are news, twitter and blogs.