• Journal of KIISE
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• v.42 no.1
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• pp.7-14
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• 2015

Storage Class Memory(SCM) has been considered as a next-generation storage device because it has positive advantages to be used both as a memory and storage. However, there are significant problems of data consistency in recently proposed file systems for SCM such as insufficient data consistency or excessive data consistency-control overhead. This paper proposes a novel data consistency-control scheme, which changes the write mode for log data depending on the modified data ratio in a block, using a rollback-recovery scheme instead of the Write Ahead Logging (WAL) scheme. The proposed scheme reduces the log data size and the synchronization cost for data consistency. In order to evaluate the proposed scheme, we implemented our scheme on a Linux 3.10.2-based system and measured its performance. The experimental results show that our scheme enhances the write throughput by 9 times on average when compared to the legacy data consistency control scheme.

• Convergence Security Journal
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• v.23 no.4
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• pp.17-22
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• 2023

Traditional authentication systems typically involve users entering their username and password into a centralized identity management system. To address the inconvenience of such authentication methods, a decentralized identity authentication system based on Distributed Identifiers(DID) is proposed, utilizing decentralized identity technology. The proposed system employs QR code scanning for login, enhancing security through the use of blockchain technology to ensure the uniqueness and safety of user identities during the login process. This system utilizes DIDs and integrates the InterPlanetary File System(IPFS) to securely manage organizational members' identity information while keeping it private. Using the distributed identity authentication system proposed in this study, it is possible to effectively manage the security and personal identity of organization members. To improve the usability of the system proposed in this study, research is needed to expand it into a solution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1355-1360
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• 2014

In this paper, we apply the learning of the mobile robot insect augmented reality Digilog Book. In the era of electronic, book written in paper space just have moved to virtual reality space. The virtual reality, constraints spatial and physical, in the real world, it is a technique that enables to experience indirectly situation not experienced directly as user immersive experience type interface. Applied to the learning robot Digilog Book that allows the fusion of paper analog and digital content, using the augmented reality technology, to experience various interactions. Apply critical elements moving, three-dimensional images and animation to enrich the learning, for easier block assembly, designed to grasp more easily rank order between the blocks. Anywhere at any time, is capable of learning of the robot in Digilog Book to be executed by the mobile phone in particular.

• KNOM Review
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• v.21 no.2
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• pp.18-25
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• 2018

Since the development of block-chain technology by Satoshi Nakamoto and Bitcoin pioneered a new cryptocurrency market, a number of scale of cryptocurrency have emerged. There are crimes taking place using the anonymity and vulnerabilities of block-chain technology, and many studies are underway to improve vulnerability and prevent crime. However, they are not enough to detect users who commit crimes. Therefore, it is very important to detect abnormal behavior such as money laundering and stealing cryptocurrency from the network. In this paper, the characteristics of the transactions and user graphs in the Bitcoin network are collected and statistical information is extracted from them and presented as plots on the log scale. Finally, we analyze visualized plots according to the Densification Power Law and Power Law Degree, as a result, present features appropriate for detection of anomalies involving abnormal transactions and abnormal users in the Bitcoin network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.241-244
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• 2014

In this paper, we apply the learning of the mobile robot insect augmented reality Digilog Book. In the era of electronic, book written in paper space just have moved to virtual reality space. The virtual reality, constraints spatial and physical, in the real world, it is a technique that enables to experience indirectly situation not experienced directly as user immersive experience type interface. Applied to the learning robot Digilog Book that allows the fusion of paper analog and digital content, using the augmented reality technology, to experience various interactions. Apply critical elements moving, three-dimensional images and animation to enrich the learning, for easier block assembly, designed to grasp more easily rank order between the blocks. Anywhere at any time, is capable of learning of the robot in Digilog Book to be executed by the mobile phone in particular.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.417-425
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• 2019

Storage snapshot technology allows to preserve data at a specific point in time, and recover and access data at a desired point in time. It is an essential technology for storage protection application. Existing snapshot methods have some problems in that they dependent on storage hardware vendor, file system or virtual block device. In this paper, we propose a new snapshot method for solving the problems and creating snapshots on-line. The proposed snapshot method uses a method of extracting the log records of update operations at the virtual file system layer to enable the snapshot method to operate independently on file systems, virtual block devices, and storage hardwares. In addition, the proposed snapshot mehod creates and manages snapshots for directories and files without interruption to the storage service. Finally, through experiments we measure the snapshot creation time and the performance degradation caused by the snapshot.

• Information Systems Review
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• v.22 no.4
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• pp.135-161
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• 2020

With the growth of blockchain and cryptocurrency-related markets, cryptocurrency exchanges are growing as a new industry. However, as the legal and regulatory definitions of cryptocurrencies are still in progress, unlike existing industrial groups, they are not under the supervision of regulatory agencies. As a result, users (i.e., cryptocurrency investors) have suffered two types of damage that could occur from hacking and other accidents on the exchanges. One type of the damage is the loss of assets caused by the extortion of personal information or account and the other is the damage from users who might be involved in external frauds. Both are analyzed in comparison with existing operators whose functions are like the exchanges. The results of this study show that membership (KYC: Know Your Client), log-in, and additional authentication in transactions are on the similar level to those of the operators while the fraud detection system (FDS) and anti-money laundering (AML) of fiat currencies and cryptocurrencies need rapid improvement.

• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.207-213
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• 2024

In this paper, we study how to improve the performance of a machine learning-based automatic music transcription model by adding musical information to the input data. Where, the added musical information is information on the number of pitches that occur in each time frame, and which is obtained by counting the number of notes activated in the answer sheet. The obtained information on the number of pitches was used by concatenating it to the log mel-spectrogram, which is the input of the existing model. In this study, we use the automatic music transcription model included the four types of block predicting four types of musical information, we demonstrate that a simple method of adding pitch number information corresponding to the music information to be predicted by each block to the existing input was helpful in training the model. In order to evaluate the performance improvement proceed with an experiment using MIDI Aligned Piano Sounds (MAPS) data, as a result, when using all pitch number information, performance improvement was confirmed by 9.7 % in frame-based F1 score and 21.8 % in note-based F1 score including offset.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.71-76
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• 2006

핸드폰, 스마트폰, PDA와 같은 모바일 디바이스는 위치, 전화기록, SMS, 사진, 동영상 등 사용자에 관한 다양한 정보를 지속적으로 수집하는데 유용하다. 최근, 모바일 디바이스로부터 수집된 정보를 토대로 개인의 일상을 요약하거나 상위 수준의 행동을 추론하는 등의 서비스를 제공하려는 연구가 진행되고 있다. 본 논문에서는 모바일 디바이스에서 수집된 정보를 검색, 요약, 시각화하기 위한 플랫폼인 라이프 브라우저를 제안한다. 라이프 브라우저는 디바이스에 저장된 개인 정보를 효과적으로 검색할 수 있도록 해주고, 개념 네트워크를 활용하여 개념 검색을 지원하며, 키그래프 기반 정보 요약 기능을 제공한다. 위치 정보의 레이블링을 위해 블록 기반의 Location Positioning Server가 구축되었다. 실제 3명의 사용자를 대상으로 수집한 정보를 라이프 브라우저를 통해 회상해 보는 과정을 분석해 보았고 저수준의 로그 정보를 직접 다루는 것보다 개념 네트워크 기반 라이프 브라우저를 사용하는 것이 유용함을 확인할 수 있었다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.139-149
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• 2023

CBDC has characteristics similar to e-payments in which all records are kept by logs, so it is difficult to satisfy the anonymity level of cash. Therefore, in this study, the CBDC model that encrypts all transaction contents using the Diffie-Hellman key sharing algorithm was presented to enhance anonymity. The proposed model provides unlinkability anduntraceability. In addition, a CBDC certificate that uses pseudonym is used. Through this certificate, illegal transactions that require tracking can be tracked later by authorized institutions.