• Journal of the Korean Society for Library and Information Science
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• v.53 no.4
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• pp.171-187
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• 2019

The study aims to analyze the posts of depression-related Facebook groups to understand major topics discussed by group users. Specifically, the purpose of the study is to identify the topics and keywords of the posts to understand what users discuss about depression. Depression is a mental disorder that is somewhat sensitive in the online community, which is characterized by accessibility, openness and anonymity. The researchers have implemented a natural language-based data analysis framework that includes components ranging from Facebook data collection to the automated extraction of topics. Using the framework, we collected and analyzed 885 posts created in the past one year from the largest Facebook depression group. To derive more complete and accurate topics, we combined both automated and manual (e.g., stop words removal, topic size determination) methods. Results indicate that users discuss a variety of topics including depression in general, human relations, mood and feeling, depression symptoms, suicide, medical references, family and etc.

• Journal of the Korea Society of Computer and Information
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• v.28 no.7
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• pp.67-75
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• 2023

In this paper, we analyze the problem of the user authentication scheme that provides dynamic ID in a multi-server environment proposed by Andola et al. and propose an improved authentication one to solve this problem. As a result of analyzing the authentication scheme of Andrea et al. in this paper, it is not safe for smart card loss attack, and this attack allows users to guess passwords, and eventually, the attacker was able to generate session key. This paper proposed an improved authentication scheme to solve these problems, and as a result of safety analysis, it was safe from various attacks such as smart card loss attack, password guess attack, and user impersonation attack. Also the improved authentication scheme not only provides a secure dynamic ID, but is also effective in terms of the computational complexity of the hash function. In addition, the improved authentication scheme does not significantly increase the amount of transmission, so it can be said to be an efficient authentication scheme in terms of transmission cost.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.89-96
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• 2021

In this paper, we analyzed that the user authentication scheme for TMIS(Telecare Medicine Information System) proposed by Al-Saggaf et al. In 2019, Al-Saggaf et al. proposed authentication scheme using biometric information, Al-Saggaf et al. claimed that their authentication scheme provides high security against various attacks along with very low computational cost. However in this paper after analyzing Al-Saggaf et al's authentication scheme, the Al-Saggaf et al's one are missing random number s from the DB to calculate the identity of the user from the server, and there is a design error in the authentication scheme due to the lack of delivery method. Al-Saggaf et al also claimed that their authentication scheme were safe against a variety of attacks, but were vulnerable to password guessing attack using login request messages and smart cards, session key exposure and insider attack. An attacker could also use a password to decrypt the stored user's biometric information by encrypting the DB with a password. Exposure of biometric information is a very serious breach of the user's privacy, which could allow an attacker to succeed in the user impersonation. Furthermore, Al-Saggaf et al's authentication schemes are vulnerable to identity guessing attack, which, unlike what they claimed, do not provide significant user anonymity in TMIS.

• Information Systems Review
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• v.17 no.3
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• pp.77-94
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• 2015

As Internet has become a popular media for sharing information, users create and share tremendous volume of information including large amount of personal information in cyberspace. Sharing private information online can enhance strength of social relationship but it could also bring negative consequences like information privacy invasion. Although many companies and governments address the importance of information privacy online, there are countless cases of crimes and hackings relating personal information online world wide. Since there are some researches investigating the role of governments and organizations on online privacy domain but there is little research regarding users' privacy protection behaviors. This study investigates relationship between Internet users' information privacy protection behavior and environmental factors. Especially, this study focuses on users' behaviors regarding information privacy protection technology adoption. According to our research results, users' online privacy protective behaviors positively affected by governmental regulations expressed as an information privacy protection law. In addition, if user is allowed to use anonymity when he or she uses online services, they have more tendencies to adopt privacy protection technologies. The detailed research findings and contribution are discussed as well.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2921-2929
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• 1998

We propose an efficient off-line electronic cash system based on the certificate issued by Certificate Authority. It satisfies all the basic requirements for electronic payment system such as cash unforgeability, cash anonymity, double spending detection, no framing, etc. Our proposed system is very computationally efficient in the sense that: (1) the number of exponentiation operation imposed on the user during withdrawal phase is much smaller than any existing off-line electronic cash schemes, (2) all the computation of user's during withdrawal phase can be performed by off-line pre-processing. So the proposed system is suitable to be implemented by smart cards in both memory and computation.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.325-330
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• 2008

Production and distributon of UCC prepared User of UCC. Power law of participation is available tool for analysis of UCC user. We can devide collective intelligence and collaborative intelligence through power law of participation. We can analyze relation of paticipant and departmentalize type of participation, Power law of participation is available tool for platform design of production and distribution.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.23-28
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• 2020

A comment system is essential for communication on the Internet. However, there are also malicious comments such as inappropriate expression of others by exploiting anonymity online. In order to protect users from malicious comments, classification of malicious / normal comments is necessary, and this can be implemented as text classification. Text classification is one of the important topics in natural language processing, and studies using pre-trained models such as BERT and graph structures such as GCN and GAT have been actively conducted. In this study, we implemented a comment classification system using BERT, GCN, and GAT for actual published comments and compared the performance. In this study, the system using the graph-based model showed higher performance than the BERT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.293-298
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• 2008

Recently, with the development of mobile techniques and the consideration to conveniency of using, the research on Mobile RFID Reader technique is getting more and more attentions. Until now, all security authentication algorithms of RFID are algorithms about range between Tag and Reader. The range between Reader and backend DB is composed by wired networks, so it's supposed to be secure range. But it must be taken account of the problem of information security and privacy in wireless range during the design of Mobile RFID Reader. In this paper we design an blind signature scheme based on weil-paring finite group's ECC encryption scheme, and by using this blind signature we propose the anonymous authorization scheme to Mobile RFID Reader's users.

• Review of KIISC
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• v.13 no.5
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• pp.113-122
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• 2003

현대는 인터넷과 컴퓨터 없이는 잠시도 운용될 수 없는 사회이지만 이를 불법적으로 이용한 범죄행위도 점차 증가하고 있다. 이들 컴퓨터 범죄는 익명성에 기반한 대담성을 보이고 있으며, 개인의 사회적 존재로써의 자각에 있어서도 탈개인화됨에 따라 더 많은 우려를 낳고 있다. 이에 따라 일반 컴퓨터 사용자들의 프라이버시 보호를 위한 방법으로 암호화 방법을 점점 더 많이 사용하고 있는데, 이에 비례해 범죄자들의 암호사용도 증가하고 있다. 그렇다면, 범죄자들이 암호를 사용해 자신들의 범죄증거를 숨기고 있는 경우, 이를 수사하기 위해 공권력 및 수사기관은 어떻게 해야 될 것인가\ulcorner 본 논문은 이러한 문제제기를 통해 새로운 환경에 의해 변화된 코드를 활용하는 새로운 법제도를 통한 적극적인 대비방안을 모색해 보고자 한다. KLS와 같은 신기술을 수사기관 및 법집행기관이 신중하게 사용하여 국가의 법 집행력과 프라이버시권이라는 두 가지 근본 가치의 균형을 이룰 수 있는 방안을 고려하여야 할 것이다. PRIVACY와 SECURITY라는 동전의 양면은 현실생활의 법제도를 그대로 옮겨놓는 것만으로는 한계가 있다. 현재 암호와 관련한 보든 논의는 공론화 되지 못하고있다. 좀 더 공개적으로 암호를 사용한 범죄 행위에 대한 현황과 또 이를 대처한 수사기관의 수사 활동에 대해 논의하고, 그 과정에서 어떤 문제점들이 발생되고 있으며, 이들 문제를 해결하기 위해 필요한 조치들이 무엇인지에 대해 논의하고, 해외 각 국은 이 문제를 해결하기 위해 어떠한 노력들을 기울이고 있는지 살펴본후 종합적인 안목으로 시의 적절한 대책을 세우는 시발점이 되었으면 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.335-343
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• 2014

It is more important to ensure the credibility of internet media which influence the public opinion. However, there are vague suspicions in public from the examples of manipulation of online reviews with anonymity. In this study, we explore the possibility of manipulating public opinion in online web sites. We investigate the characteristics of comments posted by users on web sites and compare each comments by using the cosine similarity function. Our result shows followings. First, we found a correlation between the similarities of comments and the article ranks in the web sites. Second, it is possible to identify abnormal user activities indicating excessive multiple posting, double posting and astroturf activities.