• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.1-11
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• 2022

In this paper, we propose an NFT(Non-Fungible Token)-based access control method for safely sharing data between users in blockchain environment. Since all data stored in the blockchain can be accessed by anyone due to the nature of the technology, it is necessary to control access except for authorized users when sharing sensitive data. For that, we generate each data as NFT and controls access to the data through the smart contract. In addition, in order to overcome the limitations of single ownership of the existing NFT, we separated the NFT into ownership and use rights, so that data can be safely shared between users. Ownership is represented as an original NFT, use rights is represented as a copied NFT, and all data generated as NFT is encrypted and uploaded, so data can be shared only through the smart contract with access control. To verify this approach, we set up a hypothetical scenario called Building Information Modeling (BIM) data trade, and deployed a smart contract that satisfies 32 function call scenarios that require access control. Also, we evaluated the stability in consideration of the possibility of decryption through brute-force attack. Through our approach, we confirmed that the data can be safely shared between users in blockchain environment.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.133-145
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• 2018

This study was investigated the necessity and possibility of using block-chain technology in online used-goods trading platform. Current online used-goods trading platforms operate a safety trading system, but it is difficult to utilize due to relatively high commission rate. As a result, people mainly use the method of meeting and purchasing in person, which is a relatively costly method. This study discusses how to build a platform to solve or mitigate problems such as privacy, information distortion and omission, fraud, etc. In the platform proposed in this study, it is possible to solve the major fraud and personal information protection problems that may occur in the transaction proceeding by appropriately reflecting the types and characteristics of the block-chain technology. In future work, we will discuss legal framework and technology development plan to apply the proposed platform in this study.

• Tunnel and Underground Space
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• v.17 no.6
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• pp.464-474
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• 2007

An enhancement in the performance and safety of a high-level waste repository requires a validation of its engineered barrier. An engineering-scale test (named "KENTEX") has been conducted to investigate the thermal-hydro-mechanical behaviors in the engineered barrier of the Korean reference disposal system The validation test started on May 31, 2005 and is still under operation. The experimental data obtained allowed a preliminary and qualitative interpretation of the thermal-hydro-mechanical behaviors in the bentonite blocks. The temperature was higher as it became closer to the heater, while it became lower as it was farther away from the heater. The water content had a higher value in the part close to the hydration surface than that in the heater part. The relative humidity data suggested that a hydration of the bentonite blocks might occur by different drying-wetting processes, depending on their position. The total pressure was continuously increased by the evolution of the saturation front in the bentonite blocks and thereby the swelling pressure. Near the heater region, there was also a significant contribution of the thermal expansion of bentonite and the vapor pressure in the pores of the bentonite blocks.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.55-61
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• 2017

Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.17-23
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• 2020

With the advancement of AI technology, legal status and regulation issues for AI robots, and the necessity of a robot registration system are emerging. Since the shape and activity area of AI robots will no longer be limited to hardware in one country, the definition and regulation of AI robots should be expanded to a comprehensive concept including software, and information about them should be securely managed and shared by governments around the world. From this perspective, we extend 'AI robot' to the concept of Juridical AI encompassing hardware and software, and propose a method to operate the Juridical AI registration system using a permissioned blockchain called Juridical AI Chain. Since blockchain is an internationally distributed database, operating such AI registration system based on the blockchain will be a way to effectively cope with the global problems caused by the commercialization of AI robots.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.445-451
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• 2014

The related-key attack is regarded as one of the important cryptanalytic tools for the security evaluation of block ciphers. This is due to the fact that this attack can be effectively applied to schemes like block-cipher based hash functions whose block-cipher keys can be controlled as their messages. In this paper, we improve the related-key attack on lightweight block cipher PRINCE proposed in FSE 2013. Our improved related-key attack on PRINCE reduces data complexity from $2^{33}$ [4] to 2.

• Journal of IKEEE
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• v.23 no.2
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• pp.508-516
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• 2019

Smart home with various IoT devices provides convenient and efficient services. However, security is important because sensitive information such as private video and audio can be collected and processed, as well as shared over the Internet. To manage such smart home IoT devices, we use blockchain technology that provides data integrity and secure management. In this paper, we utilize a PoS(Proof of Stake) method that verifies the block through the accumulated stake in the network rather than the computation power, out of the PoW(Proof of Work) block chain, in which the computation for the existing verification must be continuously performed. Among them, we propose a blockchain based system with DPoS(Delegated Proof of Stake) method to actively solve the scalability part, for security that is suitable for smart home IoT environment. We implement the proposed system with DPoS based EOSIO to show realization, and we show performance improvement in terms of transaction processing speed.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.12
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• pp.307-314
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• 2020

The video surveillance service is being widely deployed around our lives and the service stores sensitive data such as video streams in the cloud over the Internet or the centralized data store in an on-premise environment. The main concerning of these services is that the user should trust the service provider how secure the video or data is stored and handled without any concrete evidence. In this paper, we proposed the approach to protecting video by PKI (public key infrastructure) with a blockchain network. The video is encrypted by a symmetric key, then the key is shared through a blockchain network with taking advantage of the PKI mechanism. Therefore, the user can ensure the sensitive data is always kept secure and traceable in its lifecycle.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.1-8
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• 2022

With the development of communication infrastructure, the number of network equipment owned by one person is gradually increasing. General-purpose devices such as smartphones can implement theft/loss prevention function by implementing S/W. However, other small devices lack practicality such as long-distance communication problems due to standard communication technology specifications or H/W limitations, and lack of functions(authentication and security). This study combines the Lora communication protocol in the LPWA standard environment and the blockchain technology. Anti-theft and security functions were added to the protocol, and the PBFT consensus algorithm was applied to build a blockchain network. As a result of the test, the effectiveness of safety(authentication and trust network) and performance(blockchain processing performance) were confirmed. This study aims to contribute to the future development of portable or small device anti-theft products as a 4th industrial convergence research.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.585-590
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• 2017

In this paper, a low power of safety oriented sidewalk block was implemented using dimming technology using LED and illuminance sensor to prevent glare by high - intensity light source and prevent night traffic accident. The dimming system of this paper used a light bulb color with less fatigue to prevent glare and consumed 6.10Wh power. Also, it is confirmed that the power saving is about 56.9% when compared with the existing system.