• Journal of Information Processing Systems
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• v.19 no.1
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• pp.89-97
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• 2023

With the growth of Internet-of-Things (IoT) technologies, the number of IoT devices developers need to manage has increased exponentially. Many IoT standards have been proposed to allow those devices to communicate efficiently in day-to-day tasks. However, we lack trusted interworking entities for devices from different standards to collaborate securely. This paper proposes a blockchain platform that bridges multiple heterogeneous IoT platforms to co-exist and interwork. Specifically, we designed an interworking proxy application entity (IPE) implemented as a chaincode in Hyperledger Fabric to collect and process data coming from/to oneM2M and LWM2M architecture. The use of blockchain will guarantee network reliability and data integrity so that cross-standard communications can be audited and processed securely. Based on our evaluation, we show that the interworking between oneM2M and LWM2M through our blockchain platform is feasible. Furthermore, the proposed system can process up to 206 transactions per second with 1,000 running applications, which is about an 87% increase from the previously referenced study.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.219-227
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• 2019

This study aims to examine Blockchain research trend using bibliometrics-based network analysis. The data were collected from WoS, Scopus, Korea Citation Index and National science & Technology Information Service, from 2009 to 2018. As results, the number of publications has started increasing rapidly from 2017 and it showed the initial stage of formation of coauthor network. Words often used in the title of the publications were related to application development, controversy and technology development. In addition, the majority of domestic papers are in the subject of social science, while international papers tend to focus on engineering issues. The results of the temporal analysis show that Korean researchers' block chain 3.0 started in 2017 and are rapidly increasing in 2018. The number of citations was associated with publication year in a statistically signifiant way. By examining these research trends, we hope that this paper can be a useful basis for the development of blockchain. Future research is expected to reveal more clearly the knowledge structure and characteristics of blockchain around the world.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.2
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• pp.51-58
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• 2022

Blockchain technology is a system in which data from users participating in blockchain networks is distributed and stored. Bitcoin and Ethereum are attracting global attention, and the utilization of blockchain is expected to be endless. However, the need for blockchain data privacy protection is emerging in various financial, medical, and real estate sectors that process personal information due to the transparency of disclosing all data in the blockchain to network participants. Although studies using smart contracts, homomorphic encryption, and cryptographic key methods have been mainly conducted to protect existing blockchain data privacy, this paper proposes data privacy using matrix character relocation techniques differentiated from existing papers. The approach proposed in this paper consists largely of two methods: how to relocate the original data to matrix characters, how to return the deployed data to the original. Through qualitative experiments, we evaluate the safety of the approach proposed in this paper, and demonstrate that matrix character relocation will be sufficiently applicable in private blockchain environments by measuring the time it takes to revert applied data to original data.

• Journal of Yeungnam Medical Science
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• v.40 no.2
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• pp.156-163
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• 2023

Background: Interest in digital medical information has increased because it allows doctors to easily access a patient's medical records and provide appropriate medical care. Blockchain technology ensures data safety, reliability, integrity, and transparency by distributing medical data to all users over a peer-to-peer network. This study attempted to assess pediatricians' thoughts and attitudes toward introducing blockchain technology into the medical field. Methods: This study used a questionnaire survey to examine the thoughts and attitudes of 30- to 60-year-old pediatricians regarding the introduction of blockchain technology into the medical field. Responses to each item were recorded on a scale ranging from 1 (never agree) to 7 (completely agree). Results: The scores for the intentions and expectations of using blockchain technology were 4.0 to 4.6. Pediatricians from tertiary hospitals responded more positively (4.5-4.9) to the idea of using blockchain technology for hospital work relative to the general population (4.3-4.7). However, pediatricians working in primary and secondary hospitals had a slightly negative view of the application of blockchain technology to hospital work (p=0.018). Conclusion: When introducing the medical records of related pediatric and adolescent patients using blockchain technology in the future, it would be better to conduct a pilot project that prioritizes pediatricians in tertiary hospitals. The cost, policy, and market participants' perceptions are essential factors to consider when introducing technology in the medical field.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.5
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• pp.1021-1035
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• 2024

This paper proposes the TEE-BOP (Trusted Execution Environment-Based Blockchain Offline Payment) protocol for blockchain-based offline payments. TEE-BOP securely manages offline balances within a Trusted Execution Environment (TEE) and efficiently verifies initial deposit proofs recorded on the blockchain using Merkle trees. Additionally, it ensures secure and tamper-proof transactions in offline environments by guaranteeing the reliability of keys and the system through TEE Attestation. Unlike previous studies, TEE-BOP enhances real-world applicability by eliminating dependence on central authorities and avoiding assumptions of ideal models. The protocol solves the double-spending problem through multi-layered defense mechanisms and addresses forgery prevention by allowing recipients to directly verify data consistency between the TEE and the blockchain. This enables reliable blockchain-based offline payments in areas with unstable network infrastructure. It demonstrates that this research can expand the application of blockchain technology and contribute to improving access to financial services in developing countries or disaster situations.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.457-463
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• 2019

The blockchain and crypto currency has become one of the most essential components of a communication network in the recent years. Through communication networking, we browse the internet, make VoIP phone calls, have video conferences and check e-mails via computers. A lot of researches are being conducting to address the blockchain and crypto currency challenges in communication networking and provide corresponding solutions. In this paper, a diverse kind of novel research works in terms of mechanisms, techniques, architectures, and frameworks have been proposed to provide possible solutions against the existing challenges in the communication networking. Such novel research works involve thermal load capacity techniques, intelligent sensing mechanism, secure cloud computing system communication algorithm for wearable healthcare systems, sentiment analysis, optimized resources.

• Electronics and Telecommunications Trends
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• v.37 no.3
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• pp.85-96
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• 2022

Recently, the blockchain technology, which can decentralize business ecosystems using secure transactions without trusted intermediaries, has been spotlighted. Full nodes play an important role in maintaining decentralization in that they independently verify transactions using their full historical transaction data. However, the storage requirement of a full node for storing historical data is continuously increasing, and thus, has become harder for users to run a full node due to the heavy price for storage costs. In this paper, we investigate research trends on reducing the costs of storing blockchain transaction data so that nodes with low storage requirements can be used in the blockchain network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.680-682
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• 2022

The closed-loop supply chain's central enterprises aim to maximize the revenue and reduce the reclaiming channel level to the greatest extent by using blockchain and modern management methods. The traditional recycling network has more links, and there is less communication between enterprises in each link. There is a particular "bullwhip effect" in the channel link, making it difficult for power battery manufacturers to respond to the dynamic market quickly. It is often challenging to obtain scaled waste power batteries, which aggravates how power battery raw materials are expensive and difficult to recycle. Therefore, the closed-loop supply chain design of power batteries adopting blockchain shall minimize channel links and reduce transaction levels to reduce costs.

• The Journal of Industrial Distribution & Business
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• v.9 no.6
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• pp.77-85
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• 2018

Purpose - The purpose of this study is to subdivide trade transaction-centered structure in a logistics/distribution industry system to apply blockchain, to establish and resolve with which types of technology, and to provide policy direction of government institution and technology to apply blockchain in this kind of industry. Research design, data, and methodology - This study was conducted with previous researches centered on cases applied in various industry sectors on the basis of blockchain technology. Results - General fields of blockchain application include digital contents distribution, IoT platform, e-Commerce, real-estate transaction, decentralized app. development(storage), certification service, smart contract, P2P network infrastructure, publication/storage of public documents, smart voting, money exchange, payment/settlement, banking security platform, actual asset storage, stock transaction and crowd funding. Blockchain is being applied in various fields home and abroad and its application cases can be explained in the banking industry, public sector, e-Commerce, medical industry, distribution and supply chain management, copyright protection. As examined in the blockchain application cases, it is expected to establish blockchain that can secure safety through distributed ledger in trade transaction because blockchain is established and applied in various sectors of industries home and abroad. Parties concerned of trade transaction can secure visibility even in interrupted specific section when they provide it as a base for distributed ledger application in trade and establish trade transaction model by applying blockchain. In case of interrupted specific section by using distributed ledger, blockchain model of trade transaction needs to be formed to make it possible for parties concerned involved in trade transaction to secure visibility and real-time tracking. Additionally, management should be possible from the time of contract until payment, freight transfer to buyers through land, air and maritime transportation. Conclusions - In order to boost blockchain-based logistics/distribution industry, the government, institutionally, needs to back up adding legal plan of shipping, logistics and distribution, reviewing standardization of electronic switching system and coming up with blockchain-based industrial road maps. In addition, the government, technologically, has to support R&D for integration with other high technology, standardization of distribution industry's blockchain technology and manpower training to expand technology development.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.45-53
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• 2020

Blockchain can control transactions in a decentralized way and is already being considered for manufacturing, finance, banking, logistics, and medical industries due to its advantages such as transparency, security, and flexibility. And it is predicted to have a great economic effect. However, Blockchain has a Trilemma that is difficult to simultaneously improve scalability, decentralization and security characteristics. Among them, the biggest limitation of blockchain is scalability, which is very difficult to cope with the constantly increasing number of transactions and nodes. To make the blockchain scalable, higher performance should be achieved by modifying existing consensus methods or by improving the characteristics and network efficiency that affect many ways of scaling. Therefore, in this paper, we propose a cluster-based scalable PBFT consensus algorithm called CBS-PBFT which reduces the message complexity O(n²) of PBFT to O(n), which is a representative consensus algorithm of blockchain, and the validity is verified through simulation experiments.