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Young-Jin Ko

Sungkyunkwan University · Computer Science

About the Lab

Professor Young-Jin Ko's research lab specializes in text mining, information retrieval, and natural language processing, with a strong focus on automatic text categorization and cross-language information retrieval. The lab develops innovative methods that leverage unsupervised and semi-supervised learning techniques to reduce reliance on costly labeled data, emphasizing feature weighting, sentence importance, and bootstrapping frameworks. A key research direction involves constructing and utilizing multilingual resources—such as bilingual dictionaries and parallel corpora—from large-scale sources like Wikipedia to enhance cross-lingual text processing. The lab also explores efficient term-weighting schemes tailored specifically for text categorization, distinguishing it from traditional information retrieval approaches.

text categorizationcross-language retrievalunsupervised learningparallel corporaterm weighting

Research Overview

Papers
192
Total Citations
2,301
Papers (5y)
52
Primary Field
Computer Science

Research Output Trend

Figures are computed from collected data and may differ slightly.

Publications per year (5y)
52total
2022
2023
2024
2025
2026
Citations per year (5y)
187total
20222023202420252026

Selected Papers

15
1
Article|151 citations·2012
A study of term weighting schemes using class information for text classification
Youngjoong Ko

No abstract available.

Artificial IntelligenceComputer Science
2
Article|150 citations·2000
Automatic text categorization by unsupervised learning
Youngjoong Ko, Jungyun Seo
OA

The goal of text categorization is to classify documents into a certain number of predefined categories. The previous works 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 an unsupervised learning method to overcome the

Artificial IntelligenceComputer Science
3
Article|118 citations·2002
Improving text categorization using the importance of sentences
Youngjoong Ko, Jinwoo Park, Jungyun Seo
SJR Q1Information Processing & Management
Artificial IntelligenceComputer Science
4
Article|77 citations·2008
An effective sentence-extraction technique using contextual information and statistical approaches for text summarization
Youngjoong Ko, Jungyun Seo
SJR Q1Pattern Recognition Letters
Artificial IntelligenceComputer Science
5
Article|68 citations·2007
Using classification techniques for informal requirements in the requirements analysis-supporting system
Youngjoong Ko, Sooyong Park, Jungyun Seo, Soonhwang Choi
SJR Q1Information and Software Technology
Artificial IntelligenceComputer Science
6
Article|61 citations·2008
Text classification from unlabeled documents with bootstrapping and feature projection techniques
Youngjoong Ko, Jungyun Seo
SJR Q1Information Processing & Management
Artificial IntelligenceComputer Science
7
Article|42 citations·2022
Effective fake news video detection using domain knowledge and multimodal data fusion on youtube
Hye-Won Choi, Youngjoong Ko
SJR Q1Pattern Recognition Letters
Sociology and Political ScienceSocial Sciences
8
Article|36 citations·2021
Word sense disambiguation based on context selection using knowledge-based word similarity
Sunjae Kwon, Dongsuk Oh, Youngjoong Ko
SJR Q1Information Processing & Management
Artificial IntelligenceComputer Science
9
Article|35 citations·2023
Knowledge graph extension with a pre-trained language model via unified learning method
Bonggeun Choi, Youngjoong Ko
SJR Q1Knowledge-Based Systems
Artificial IntelligenceComputer Science
10
Article|30 citations·2002
Automatic text categorization using the importance of sentences
Youngjoong Ko, Jinwoo Park, Jungyun Seo
OA

Automatic text categorization is a problem of automatically assigning text documents to predefined categories. In order to classify text documents, we must extract good features from them. In previous research, a text document is commonly represented by the term frequency and the inverted document frequency of each feature. Since there is a difference between important sentences and unimportant sentences in a document, the features from more important sentences should be considered more than oth

Artificial IntelligenceComputer Science
11
Article|27 citations·2004
Learning with unlabeled data for text categorization using bootstrapping and feature projection techniques
Youngjoong Ko, Jungyun Seo
OA

A wide range of supervised learning algorithms has been applied to Text Categorization. However, the supervised learning approaches have some problems. One of them is that they require a large, often prohibitive, number of labeled training documents for accurate learning. Generally, acquiring class labels for training data is costly, while gathering a large quantity of unlabeled data is cheap. We here propose a new automatic text categorization method for learning from only unlabeled data using

Artificial IntelligenceComputer Science
12
Article|26 citations·2017
How to use negative class information for Naive Bayes classification
Youngjoong Ko
SJR Q1Information Processing & Management
Artificial IntelligenceComputer Science
13
Article|26 citations·2016
How to Improve Text Summarization and Classification by Mutual Cooperation on an Integrated Framework
Hyoungil Jeong, Youngjoong Ko, Jungyun Seo
SJR Q1Expert Systems with Applications
Artificial IntelligenceComputer Science
14
Article|20 citations·2008
Pseudo-relevance feedback and statistical query expansion for web snippet generation
Youngjoong Ko, Hongkuk An, Jungyun Seo
SJR Q3Information Processing Letters
Information SystemsComputer Science
15
Article|19 citations·2003
Using the feature projection technique based on a normalized voting method for text classification
Youngjoong Ko, Jungyun Seo
SJR Q1Information Processing & Management
Artificial IntelligenceComputer Science

Research Areas

Artificial IntelligenceInformation SystemsComputer Vision and Pattern RecognitionSociology and Political ScienceComputational Theory and MathematicsOncology

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