• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.17-25
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• 2022

Hash functions are widely used for fast equality analysis of video files because of their fixed small output sizes regardless of their input sizes. However, the hash function has the possibility of a hash collision in which different inputs derive the same output value, so there is a problem that different video files may be mistaken for the same file. In this paper, we propose an equality analysis scheme in which different video files always derive different output values using identifier information and double hash. The scheme first extracts the identifier information of an original video file, and attaches it into the end of the original file with a steganography method. Next the scheme calculates two hash output values of the original file and the extended file with attached identifier information. Finally the scheme utilizes the identifier information, the hash output value of the original file, and the hash output value of the extended file for the equality analysis of video files. For evaluation, we implement the proposed scheme into a practical software tool and show that the proposed scheme performs well the equality analysis of video files without hash collision problem and increases the resistance against the malicious hash collision attack.

• Convergence Security Journal
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• v.24 no.1
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• pp.51-57
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• 2024

Although industrial control systems (ICSs) recently keep evolving with the introduction of Industrial IoT converging information technology (IT) and operational technology (OT), it also leads to a variety of threats and vulnerabilities, which was not experienced in the past ICS with no connection to the external network. Since various control command messages are sent to field devices of the ICS for the purpose of monitoring and controlling the operational processes, it is required to guarantee the message integrity as well as control center authentication. In case of the conventional message integrity codes and signature schemes based on symmetric keys and public keys, respectively, they are not suitable considering the asymmetry between the control center and field devices. Especially, compromised node attacks can be mounted against the symmetric-key-based schemes. In this paper, we propose message authentication scheme based on double hash chains constructed from cryptographic hash function without introducing other primitives, and then propose extension scheme using Merkle tree for multiple uses of the double hash chains. It is shown that the proposed scheme is much more efficient in computational complexity than other conventional schemes.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.38-42
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• 2017

This paper introduces the concept of a dual hash function to amplify security in a quantum key distribution system. We show the use of the relationship between quantum error correction and security to provide security amplification. Also, in terms of security amplification, the approach shows that phase error correction offers better security. We describe the process of enhancing security using the universal hash function using the BB84 protocol, which is a typical example of QKD. Finally, the deterministic universal hash function induces the security to be evaluated in the quantum Pauli channel without depending on the length of the message.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.6
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• pp.25-30
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• 2012

Passwords are a common method of identifying and authenticating a user who wishes to log on to a secure system. Password-based authentication techniques, however, do not provide strong security and recognized as being an poor form of protection. It is not all the responsibility of the user to control password and to protect its confidentiality. In this paper, confirm an appropriate response time and I propose a new and improved method of implementing two factor authentication using SMS via receiving apparatus(mobile and email).

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1045-1048
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• 2005

유전자 칩의 정확성은 각 유전자들의 식별자로 활용되는 probe들에 의해 결정된다. 일반적으로 칩을 구성하는 probe들은 반응 오류를 예측하기 위해 이중구조와 녹는점과 같은 요소들을 고려한다. 또한 다른 유전자들과의 교차반응을 최소화하기 위해 각 probe들의 specificity도 고려되어야 한다. probe가 specificity를 보장하는지 검증하는 것은 전체 유전자들을 탐색해야 하므로 대규모 인간염색체에 대해서는 많은 시간이 소요된다. 본 논문에서는 specificity를 만족하는 probe들을 선택하는 효율적인 알고리즘을 제시한다. 제시한 알고리즘은 해시 테이블을 활용하여 probe가 specificity를 만족하지 못하게 하는 유전자 시퀀스들만을 탐색하여 비교한다. 제시한 알고리즘이 기존 알고리즘보다 효율적임을 실험결과를 통해 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.913-915
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• 2005

유전자 칩의 정확성은 각 유전자들의 식별자로 활용되는 probe들에 의해 결정된다. 칩에 삽입되는 probe들은 반응오류를 피하기 위해 이중구조, 녹는점, 그리고 CG구조와 같은 요소들을 고려한다. 또한 다른 유전자들과의 교차반응을 최소화하기 위해 specificity를 고려한다. probe의 specificity 검증은 전체 유전자들에 대해 탐색해야 하므로 대규모 염색체에 대해서는 많은 계산이 요구된다. 본 논문에서는 specificity 검증을 위한 효율적인 알고리즘을 제시한다. 제시한 알고리즘은 해시테이블을 활용하여 probe가 specificity를 만족하지 못하게 하는 유전자 시퀀스들만을 탐색하여 비교한다. 제시한 알고리즘이 기존 알고리즘보다 효율적임을 실험결과를 통해 보인다.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.129-135
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• 2013

With the increasing use of the SNS, WOM(Word of Mouth) has become an even more powerful and useful resource for consumers and marketers. In this paper, we investigated the effects of message polarity (positive, neutral, negative) and type (factual, evaluative) on WOM through SNS (twitter). A total of 13.4 million twitter messages were collected and 1.0 million retweeted messages were analyzed. The results showed that message orientation, type, URL and hashtag have a significant (<0.01) effect on retweet counts and the interaction between message orientation and other factors were observed. It also observed that message type, URL and hashtag have significant (0.05) relationships with retweet speed.

• Journal of Convergence for Information Technology
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• v.8 no.3
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• pp.85-90
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• 2018

Blockchain technology provides distributed trust structure; with this, we can implement a system that cannot be forged and make Smart Contract possible. With blockchain technology emerging as next generation security technology, there have been studies on authentication and security services that ensure integrity. Although Internet-based services have been going with user authentication with password, the information can be stolen through a client and a network and the server is exposed to hacking. For the reason, we suggest blockchain technology and OTP based authentication mechanism to ensure integrity. In particular, the Two-Factor Authentication is able to ensure secure authentication by combining OTP authentication and biometric authentication without using password. As the suggested authentication applies multiple hash functions and generates transactions to be placed in blocks in order for biometric information not to be identified, it is protected from server attacks by being separate from the server.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.393-400
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• 2003

Excessive generation of BOG during the LNG transportation not only causes the severe financial loss but also leads to the unexpected disaster. Therefore, the carrier cargo insulating interior LNG should be carefully designed based upon an accurate heat transfer analysis. However. it is not simple to analyze heat transfer of LNG cargo, because it is in a complex insulation structure and LNG carrier experiences a complicated heat transfer according to various kinds of voyage conditions. In this paper, we carried out the transient finite element heat transfer analysis for a cargo of Mark-111 membrane-type LNG carrier during laden voyage, and we compared heat transfer rates between considering natural convection and considering conduction. For this goal, we developed a PCL program incorporating with a commercial MSC/NASTRAN FEM code.

• Journal of Korean Library and Information Science Society
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• v.52 no.2
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• pp.401-428
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• 2021

Recently, libraries are trying to communicate with users using various social media. Among them, Instagram is the most used SNS by users recently. Therefore, in this study, in order to effectively operate the library Instagram, we looked at how Instagram in the library is operated, what posts and contents people are interested in, and how the library can utilize it. By analyzing the Instagram operation status of Instagram, we tried to suggest improvement plans and activation plans. For this purpose, theoretical background research on SNS and Instagram, analysis of prior research, and related data were collected and analyzed. Next, for 82 domestic library accounts opened on Instagram, the library type, region, and Instagram account number of posts, 'followers', 'follows', images, etc. were collected, and the Text, hashtags, upload date, number of 'likes' and comments were analyzed. As a result of the study, it was found that increasing followers, uploading user-customized posts, formalizing account profiles, using library-specific hashtags, and communication with users are necessary to activate library Instagram.