• Journal of Computing Science and Engineering
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• 제5권2호
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• pp.150-160
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• 2011

Automatic text classification has a long history and many studies have been conducted in this field. In particular, many machine learning algorithms and information retrieval techniques have been applied to text classification tasks. Even though much technical progress has been made in text classification, there is still room for improvement in text classification. In this paper, we will discuss remaining issues in improving text classification. In this paper, three improvement issues are presented including automatic training data generation, noisy data treatment and term weighting and indexing, and four actual studies and their empirical results for those issues are introduced. First, the semi-supervised learning technique is applied to text classification to efficiently create training data. For effective noisy data treatment, a noisy data reduction method and a robust text classifier from noisy data are developed as a solution. Finally, the term weighting and indexing technique is revised by reflecting the importance of sentences into term weight calculation using summarization techniques.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6080-6096
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• 2019

Text classification is one of the fundamental techniques in natural language processing. Numerous studies are based on text classification, such as news subject classification, question answering system classification, and movie review classification. Traditional text classification methods are used to extract features and then classify them. However, traditional methods are too complex to operate, and their accuracy is not sufficiently high. Recently, convolutional neural network (CNN) based one-hot method has been proposed in text classification to solve this problem. In this paper, we propose an improved method using CNN based skip-gram method for Chinese text classification and it conducts in Sogou news corpus. Experimental results indicate that CNN with the skip-gram model performs more efficiently than CNN-based one-hot method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권3호
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• pp.285-307
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• 2009

This paper introduces DICE, a Domain-Independent text Classification Engine. DICE is robust, efficient, and domain-independent in terms of software and architecture. Each module of the system is clearly modularized and encapsulated for extensibility. The clear modular architecture allows for simple and continuous verification and facilitates changes in multiple cycles, even after its major development period is complete. Those who want to make use of DICE can easily implement their ideas on this test bed and optimize it for a particular domain by simply adjusting the configuration file. Unlike other publically available tool kits or development environments targeted at general purpose classification models, DICE specializes in text classification with a number of useful functions specific to it. This paper focuses on the ways to locate the optimal states of a practical text classification framework by using various adaptation methods provided by the system such as feature selection, lemmatization, and classification models.

• 데이타베이스연구회지:데이타베이스연구
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• 제34권3호
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• pp.3-13
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• 2018

자동문서분류(Text Classification)는 주어진 텍스트 문서를 이에 적합한 카테고리로 분류하는 텍스트 마이닝 기술 중의 하나로서 스팸메일 탐지, 뉴스분류, 자동응답, 감성분석, 쳇봇 등 다양한 분야에 활용되고 있다. 일반적으로 자동문서분류 시스템은 기계학습 알고리즘을 활용하며, 이 중에서 텍스트 데이터에 적합한 알고리즘인 나이브베이즈(Naive Bayes), 지지벡터머신(Support Vector Machine) 등이 합리적 수준의 성능을 보이는 것으로 알려져 있다. 최근 딥러닝 기술의 발전에 따라 자동문서분류 시스템의 성능을 개선하기 위해 순환신경망(Recurrent Neural Network)과 콘볼루션 신경망(Convolutional Neural Network)을 적용하는 연구가 소개되고 있다. 그러나 이러한 최신 기법들이 아직 완벽한 수준의 문서분류에는 미치지 못하고 있다. 본 논문은 그 이유가 텍스트 데이터가 단어 차원 중심의 벡터로 표현되어 텍스트에 내재한 의미 정보를 훼손하는데 주목하고, 선행 연구에서 그 효능이 검증된 시멘틱 텐서공간모델에 기반하여 심층 신경망 아키텍처를 제안하고 이를 활용한 문서분류기의 성능이 대폭 상승함을 보인다.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.87-93
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• 2012

This paper discusses a new weighting method for text analyzing from the view point of supervised learning. The term frequency and inverse term frequency measure (tf-idf measure) is famous weighting method for information retrieval, and this method can be used for text analyzing either. However, it is an experimental weighting method for information retrieval whose effectiveness is not clarified from the theoretical viewpoints. Therefore, other effective weighting measure may be obtained for document classification problems. In this study, we propose the optimal weighting method for document classification problems from the view point of supervised learning. The proposed measure is more suitable for the text classification problem as used training data than the tf-idf measure. The effectiveness of our proposal is clarified by simulation experiments for the text classification problems of newspaper article and the customer review which is posted on the web site.

• 한국지능시스템학회논문지
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• 제25권4호
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• pp.386-391
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• 2015

본 논문에서는 한국어와 중국어의 언어학적인 특징을 고려하여 문서 자동분류 시스템의 성능을 높일 수 있는 최적의 자질어 단위를 제안한다. 언어 종속적 단위인 형태소 자질어와 언어 독립적 단위인 n-gram 자질어 그리고 이들을 조합한 복합 자질어 집합을 대상으로 각 언어의 인터넷 신문기사를 SVM으로 분류하는 실험을 수행하였다. 실험 결과, 한국어 문서분류에서는 bi-gram이 F1-measure 87.07%로 가장 좋은 분류 성능을 보였고, 중국어 문서분류에서는 'uni-gram 명사 동사 형용사 사자성어'의 복합 자질어 집합이 F1-measure 82.79%로 가장 좋은 성능을 보였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.1085-1089
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• 2015

과거의 텍스트마이닝기법은 텍스트 자체의 복잡성과 텍스트 내에 산재한 변수의 자유도 때문에 분석 알고리즘을 구현하는데 어려움이 있었다. 의미 있는 정보를 얻기 위하여 어렵게 알고리즘을 구현했다고 하더라도, 기계적으로 텍스트 분석에 소요되는 시간이 텍스트를 사람이 직접 읽어 분석 하는 것보다 많은 시간이 요구 되었다. 그러나 최근 하드웨어와 분석 알고리즘의 발전과 함께 빅데이터라는 기술이 등장하였으며, 앞에서 설명한 제약사항을 극복할 수 있게 되었고, 텍스트마이닝을 통한 분석이 현실세계에서 그 가치를 충분히 인정받고 있다. 만약, 텍스트의 탐색 수준에서 벗어나 마이닝을 통하여 분석이 가능하다면 텍스트 분석에 소비되는 인적, 물적 자원의 비용을 절감할 수 있기 때문에 공공분야에서 절실히 요구되는 창조적인 일에 더 많은 자원을 효과적으로 활용할 수 있을 것이다. 이에 본 논문에서는 인적 자원이 수작업으로 하는 공공분야 문서 분류의 결과값과 빅데이터 환경에서 텍스트마이닝기반의 문서내 단어 빈도수(TF-IDF)와 문서간 코사인 유사도(Cosine Similarity)를 활용한 공공분야 문서분류의 결과값을 비교하여 평가한다.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.817-824
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• 2003

We employed a hierarchical document classification method to classify a massive collection of electronic medical records(EMR) written in both Korean and English. Our experimental system has been learned from 5,000 records of EMR text data and predicted a newly given set of EMR text data over 68% correctly. We expect the accuracy rate can be improved greatly provided a dictionary of medical terms or a suitable medical thesaurus. The classification system might play a key role in some clinical decision support systems and various interpretation systems for clinical data.

• Asia pacific journal of information systems
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• 제29권4호
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• pp.771-788
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• 2019

Deep learning techniques such as Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs) show superior performance in text classification than traditional approaches such as Support Vector Machines (SVMs) and Naïve Bayesian approaches. When using CNNs for text classification tasks, word embedding or character embedding is a step to transform words or characters to fixed size vectors before feeding them into convolutional layers. In this paper, we propose a parallel word-level and character-level embedding approach in CNNs for text classification. The proposed approach can capture word-level and character-level patterns concurrently in CNNs. To show the usefulness of proposed approach, we perform experiments with two English and three Korean text datasets. The experimental results show that character-level embedding works better in Korean and word-level embedding performs well in English. Also the experimental results reveal that the proposed approach provides better performance than traditional CNNs with word-level embedding or character-level embedding in both Korean and English documents. From more detail investigation, we find that the proposed approach tends to perform better when there is relatively small amount of data comparing to the traditional embedding approaches.

• 한국정보과학회논문지:소프트웨어및응용
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• 제26권1호
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• pp.167-167
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• 1999

The majority of text categorization systems use the term-based classification method. However, because of too many terms, this method is not effective to classify the documents in areal-time environment. This paper presents a real-time concept-based text categorization system,which classifies texts using thesaurus. The system consists of a Korean morphological analyzer, athesaurus tool, and a probability-vector similarity measurer. The thesaurus tool acquires the meaningsof input terms and represents the text with not the term-vector but the concept-vector. Because theconcept-vector consists of semantic units with the small size, it makes the system enable to analyzethe text with real-time. As representing the meanings of the text, the vector supports theconcept-based classification. The probability-vector similarity measurer decides the subject of the textby calculating the vector similarity between the input text and each subject. In the experimentalresults, we show that the proposed system can effectively analyze texts with real-time and do aconcept-based classification. Moreover, the experiment informs that we must expand the thesaurustool for the better system.