• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.293-297
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• 2007

The purpose of this study was to investigate the meaning of leisure experiences in the lives of unmarried women. To accomplish this purpose, this study focused on the cultural context of leisure activity of unmarried women. A total of 4 participants were selected through the process of purposive sampling. An ethnographic data was collected by the method of 'experiential description' phenomenologically based data on the leisure experience, participant observation, and in-depth interview. All verbal data from experiential description, participation observation, and in-depth interview were tape recorded and later transcribed, and analyzed through constant comparative method based on the phenomenological analysis. The following findings were the result of this study. three definitional components of leisure experience of unmarried women were identified as follows: 1) enjoyment and interest, 2) escape, and 3) freedom.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.83-88
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• 2018

The blockchain is the technique which is used in decentralized system instead of centralized system. Its characteristics are anonymous and transparency. However, there are still some traditional attacks. In this paper, we introduced some of the famous consensus algorithm with blockchain: Bitcoin, Algorand, and IOTA. Also, this paper talked about how each consensus algorithm tried to solve those traditional attacks such as double spending attack or sybil attack. Furthermore, if the consensus algorithm does not consider those attacks yet, then the author would introduce additional methods to solve those attacks. Furthermore, this paper proposed the new scenario that can make classical attacks be happened.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.405-416
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• 2022

Current AI technology is improving the quality of life by using machine learning based on data. When using machine learning, transmitting distributed data and collecting it in one place goes through a de-identification process because there is a risk of privacy infringement. De-identification data causes information damage and omission, which degrades the performance of the machine learning process and complicates the preprocessing process. Accordingly, Google announced joint learning in 2016, a method of de-identifying data and learning without the process of collecting data into one server. This paper analyzed the effectiveness by comparing the difference between the learning performance of data that went through the de-identification process of K anonymity and differential privacy reproduction data using actual financial data. As a result of the experiment, the accuracy of original data learning was 79% for k=2, 76% for k=5, 52% for k=7, 50% for 𝜖=1, and 82% for 𝜖=0.1, and 86% for Federated learning.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1519-1534
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• 2017

Data de-identification is the one of the technique that preserves individual data privacy and provides useful information of data to the analyst. However, original de-identification techniques like k-anonymity have vulnerabilities to background knowledge attacks. On the contrary, differential privacy has a lot of researches and studies within several years because it has both strong privacy preserving and useful utility. In this paper, we analyze various models based on differential privacy and formalize a differentially private model on financial data. As a result, we can formalize a differentially private model on financial data and show that it has both security guarantees and good usefulness.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.3
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• pp.563-577
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• 2018

In order to support secure communication in VANET(Vehicular Ad hoc Network), messages exchanged between vehicles or between vehicle and infrastructure must be authenticated. In this paper, we propose a hierarchical anonymous authentication system for VANET. The proposed system model reduces the overhead of PKG, which is a problem of previous system, by generating private keys hierarchically, thereby enhancing practicality. We also propose a two-level hierarchical identity-based signature(TLHIBS) scheme without pairings so that improve efficiency. The proposed scheme protects the privacy of the vehicle by satisfying conditional privacy and supports batch verification so that efficiently verifies multiple signatures. Finally, The security of the proposed scheme is proved in the random oracle model by reducing the discrete logarithm problem(DLP) whereas the security proof of the previous ID-based signatures for VANET was incomplete.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.78-87
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• 2009

An attribute-based signature scheme is a signature scheme where a signer's private key is associate with an attribute set and a signature is associated with an access structure. Attribute-based signature schemes are useful to provide anonymity and access control for role-based systems and attribute-based systems where an identity of object is represented as a set of roles or attributes. In this paper, we formally define the definition of attribute-based signature schemes and propose the first efficient attribute-based signature scheme that requires constant number of pairing operations for verification where a policy is represented as a disjunctive normal form (DNF). To construct provably secure one, we introduce a new interactive assumption and prove that our construction is secure under the new interactive assumption and the random oracle model.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.80-87
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• 2006

Recently, the distribution and using of the digital multimedia contents are easy by developing the internet application program and related technology. However, the digital signal is easily duplicated and the duplicates have the same quality compare with original digital signal. To solve this problem, there is the multimedia fingerprint which is studied for the protection of copyright. Fingerprinting scheme is a techniques which supports copyright protection to track redistributors of electronic inform on using cryptographic techniques. Only regular user can know the inserted fingerprint data in fingerprinting schemes differ from a symmetric/asymmetric scheme and the scheme guarantee an anonymous before recontributed data. In this paper, we present a new scheme which is the detection of colluded multimedia fingerprint by neural network. This proposed scheme is consists of the anti-collusion code generation and the neural network for the error correction. Anti-collusion code based on BIBD(Balanced Incomplete Block Design) was made 100% collusion code detection rate about the average linear collusion attack, and the hopfield neural network using (n,k)code designing for the error bits correction confirmed that can correct error within 2bits.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.703-707
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• 2008

Nowadays, Internet becomes an essential element in our life. We can make use of numerous on-line services through Internet such as information search, on-line shopping, e-mail service, etc. But, while getting the benefits of Internet service, invasion of our privacy frequently occurs because on-line service providers tend to request excessive or unnecessary personal information. So, there have been some researches on anonymous authentication, which means that user can authenticate herself, not revealing her identity or personal information. But, most of the researches are not somewhat applicable to current authentication infrastructure. In this paper, we propose a pseudonym-based anonymous PKI with short group signature. Using our proposed scheme, we can provide anonymity with conditional traceability to current PKI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.260-267
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• 2016

The Internet has brought lots of changes to us sharing information mutually. However, as all social symptom have double-sided character, it has serious social problem. Vicious users have been taking advantage of anonymity on the Internet, stating comments aggressively for defamation, personal attacks, privacy violation and more. Malicious comments on the Internet are creating the biggest problem regarding unlawful acts and insults which occur on the Internet. In order to solve the issues, several studies have been done to efficiently manage the comments. However, there are limitations to recognize modified malicious vocabulary in previous research. So, in this paper, we propose a malicious comments detection technique by improving limitation of previous studies. The experimental result has shown accuracy of 87.8% providing higher accuracy as compared to previous studies done.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.537-549
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• 2013

This study examines implications for the Korean military health survey from literature review on foreign military health surveys. The authors discuss backgrounds, objectives, participants, methods, contents, organizations involved, and cycles of foreign military health surveys from literature review from peer-reviewed journals as well as reports and documents collected from web-sites of governmental organizations. Common and distinguishing characteristics were found from foreign military health surveys. First, the military health surveys have evolved in phases in the direction of reducing health risk factors. Second, the importance of mental health is being emphasized. Third, cooperations and collaborations of governments, universities, and professional agencies are important in order to ensure anonymity and expertise on data collection and analysis. Finally, health surveys are conducted on a regular basis through institutionalization. To monitor and to promote health of military personnel, it is critical for Korea to establish the legal and institutional environment and to recognize the importance as well as the need of military health surveys at the national level.