• The Journal of Society for e-Business Studies
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• v.26 no.2
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• pp.143-155
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• 2021

In this study, we focused on the decenterization, innovation, interoperability, and transparency that blockchain technology brings in the financial services sector. Decentralized financial services powered by blockchain technology can leverage virtual assets to expand the scope of financial services and create new business opportunities while encouraging innovation in financial services. Based on the understanding of the concept of De-Fi, we will look at the need for technology and major use cases, and look at future challenges. This will help us understand the vision of developing new technologies for innovation, while identifying the potential as new areas of fintech services.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.215-216
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• 2016

본 논문에서는 NFC 모듈과 핸드폰 앱을 이용하여 좀 더 편리하게 원하는 웹페이지로 자동로그인을 해 주는 시스템을 개발하였다. 스마트폰은 NFC를 이용한 아이디와 패스워드를 포함한 데이터 송신하며 라즈베리파이는 이 데이터를 수신하여 연결된 PC에게로 전달한다. PC에서는 AUTOHOTKEY 매크로를 이용하여 원하는 웹페이지를 실행시키고 자동로그인을 수행한다. 이러한 방법을 통하여 스마트폰에 접속 정보만 가지고 있으면 어느 PC에서라도 편리하게 자동로그인할 수 있는 기반 기술을 구현하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1935-1941
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• 2021

In order to develop an algorithm using deep learning, which has been recently applied to various fields, it is necessary to have rich, high-quality learning data. In this paper, we propose an acquisition system for biological signals that simultaneously collects bio-signal data such as optical videos, thermal videos, and voices, which are mainly used in developing deep learning algorithms and useful in derivation of information, and transmit them to the server. To increase the portability of the collector, it was made based on Raspberry Pi, and the collected data is transmitted to the server through the wireless Internet. To enable simultaneous data collection from multiple collectors, an ID for login was assigned to each subject, and this was reflected in the database to facilitate data management. By presenting an example of biological data collection for fatigue measurement, we prove the application of the proposed acquisition system.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.592-598
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• 2007

The adsorption capability of cobalt phthalocyanine derivatives was investigated by means of X-ray diffractometor (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM), and temperature programmed desorption (TPD). According to TPD results for ammonia, cobalt phthalocyanine derivatives showed two desorption peaks at low temperature ($100{\sim}150^{\circ}C$) and high temperature ($350{\sim}400^{\circ}C$) indicating that there were two kinds of acidities. Tetracarboxylic cobalt phthalocyanine (Co-TCPC) has a stronger desorption peak (chemical adsorption) at high temperature and a weaker desorption peak (physical adsorption) at low temperature than cobalt phthalocyanine (Co-PC). The specific surface areas of Co-TCPC and Co-PC were 37.5 and $18.4m^2/g$, respectively. The pore volumes of Co-TCPC and Co-PC were 0.17 and $0.10cm^3/g$, respectively. The adsorption capability of triethyl amine calculated by breakthrough curve at 120 ppm of equilibrium concentration was 24.3 mmol/g for Co-TCPC and 0.8 mmol/g for Co-PC. The removal efficiencies of dimethyl sulfide of Co-TCPC and Co-PC in batch experiment of 225 ppm of initial concentration were 92 and 18%, respectively. The removal efficiencies of trimethyl amine of Co-TCPC and Co-PC in batch experiment of 118 ppm of initial concentration were 100 and 17%, respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.103-108
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• 2016

With the growing trend of pervasive computing, (the idea that technology is moving beyond personal computers to everyday devices) there is a growing demand for lightweight ciphers to safeguard data in a network that is always available. For all block cipher applications, the AES is the preferred choice. However, devices used in pervasive computing have extremely constraint environment and as such the AES will not be suitable. In this paper we design and implement a new lightweight compact block cipher that takes advantage of both S-P network and the Feistel structure. The cipher uses the S-box of PRESENT algorithm and a key dependent one stage omega permutation network is used as the cipher's P-box. The cipher is implemented on iNEXT-V6 board equipped with virtex-6 FPGA. The design synthesized to 196 slices at 337 MHz maximum clock frequency.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.7-14
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• 2019

Users who use smartphone can using knowledge-based authentication, possession-based authentication, biometric-based authentication, and token-based authentication in order to access rights to systems requiring authentication. However, desktop computer users use method only ID and password, which are knowledge-based authentication factors, due to limitations of authentication devices, despite various authentication methods. In this paper, we designed and implemented a raspberry pi based authentication system that provides multiple authentication method of a user's desired type. The implementation system uses knowledge-based authentication, possessive-based authentication, biometric-based authentication, and token-based authentication. The proposed system can provide a security function that can be used by SMEs, which is difficult to hire a security officer due to the economic burden. The implemented system can be used not only for personal use but also for enterprise, and it can be applied to various fields such as finance and game.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.600-607
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• 2021

Purpose: The purpose of this study is to examine the path of money laundering of criminal proceeds through cryptocurrency using criminal script analysis and to devise measures to prevent and prevent criminal justice agencies from doing so. Method: Based on the results of a prior study on the profit path of cryptocurrency through money laundering and criminal cases in Korea, the path of money laundering was analyzed using criminal script techniques. Result: Most of the cryptocurrencies that have been launched are converted into criminal proceeds, which are re-launched and cashed or have a vicious cycle of being used as criminal funds are used. According to the script, the route of money laundering is mainly converted to criminal proceeds from cryptocurrency exchanges using anonymity, which is repeated several times, making it very difficult to find the money using cryptocurrency in criminal justice institutions. Conclusion: As the method of money laundering using cryptocurrency is becoming more sophisticated, legal sanctions and preventive institutionalization should be prepared for the prohibition or confiscation of cryptocurrency transactions for money laundering after understanding the flow.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.59-67
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• 2021

Blockchain technology began in 2008 when an unidentified person named Satoshi Nakamoto proposed a cryptocurrency called Bitcoin. Satoshi Nakamoto had distrust of the existing financial system and wanted to implement a financial system that is robust against hacking or mannipulation without a middleman such as a bank through blockchain technology. Satoshi proposed a blockchain as a technology to prevent the creation of the bitcoin and forging of transactions, and through this, the functions of issuance, transaction, and verification of currency were implemented. Since then, Ethereum, a cryptocurrency that can implement the smart contract on the blockchain, has been developed, allowing financial products that require complex contracts such as deposits, loans, insurance, and derivatives to be brought into the area of cryptocurrency. In addition, it is expanding the possibility of substituting products provided by financial institutions through combination with real assets. These applications are defined as Decentralized Finance (DeFi). This paper was prepared to understand the overall technical understanding of DeFi and to introduce the services currently in operation. First, the technologies and ecosystems that implement the overall DeFi are explained, and then the representative DeFi services are categorized by feature and described.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.171-178
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• 2022

In this paper, we propose a classification method according to the type and characteristics of stablecoins for risk analysis, and analyze the risk factors of each stablecoin based on this classification. First, this paper explains the technologies and ecosystem of blockchain and decentralized finance(DeFi) to understand stablecoins. In addition, the operation principle of the major stablecoins currently released and used is explained for each proposed classification type. Based on this, the risk type and risk factors of each stablecoin are derived. The risk types proposed in this paper are classified as defegging, liquidation, and exploit, and the risk factors are classified as depegging due to reliability of operator, depegging due to reliability of algorithm, depegging due to failure of algorithm, liquidation due to high volatilty and oracle attack. Based on the proposed classification, we analyze the risk factors of major stablecoins currently circulating in the crypto market.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.87-91
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• 2017

Carbon-encapsulated Ni and metal Ni nanoparticles were synthesized by levitational gas condensation (LGC). Methane ($CH_4$) gas was used to coat the surface of the Ni nanoparticles. The Ni particles had a core diameter of 10 nm, and were covered by 2~3 nm thin carbon layers with multi-shells structure.The low magnetization comparing with the Ni nanoparticles without carbon-shell results in the coexistence of nonmagnetic carbon and a large surface spin percentage with disordered magnetization orientation for the nanoparticles. Biginelli reactions in the presence of L-proline and Ni and carbon encapsulated Ni nanoparticles were carried out to change the ratio between stereoisomers. The obtained S-enantiomers for 3,4-dihydropyrimidine (DHPM) using catalysts of Ni, and Ni@C was an excess of about ${\Delta}{\sim}7.4%$ and ${\Delta}{\sim}19.6%$, respectively. The nanopowders were fully recovered using magnet to reuse as a catalyst. The Ni@C was shown at same yield to formation of 3,4-DHPM, though it was recycled for catalyst in the reaction.