• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.620-627
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• 2018

With the widespread adoption of blockchain in the field of business, the importance of confidentiality of critical information has been emerging. Although blockchain models solve the security problem regarding integrity threat by sharing transactions and making them public, it is vulnerable in terms of confidentiality. Therefore, a security mechanism to provide confidentiality of critical information and private information of a firm is necessary to utilize block chain in the process of work. In order to solve the problem, we suggest Private blockchain based cryptographic protocol application model using Smart contract commitment scheme of the Ethereum. It can contribute to activation of blockchain services by enabling non-trusted participants to perform businesses through application of smart contract enhanced in terms of confidentiality and integrity to private blockchain.

• The Journal of Society for e-Business Studies
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• v.24 no.3
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• pp.1-18
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• 2019

Due to the great advances in e-Marketplace and changes in type of items purchased from the online market, it has been dramatically increased the demand of the storage and transportation under the special conditions such as restricted temperature. Especially, the cold chain needs the way to transparently measure and monitor the entire network in realtime because it has a very complicated structure and requires totally different criteria at the every different steps and items. In this research, it has been presented the performance evaluation metrics to make contract using service level agreement (SLA), the way to apply the smart contract based on blockchain, the structure of blocks, service platform and application in order to build cold chain which can prevent the risk factors by measuring and sharing information in realtime using block chain technology. In addition, we have proposed the way to store the measured performance and reputation of each player in the block using smart contract based on SLA. With the presented framework, all players including service providers as well as users can secure the information for making the rational decisions. When the service platform is actually built and operated, it seems possible to secure the information in transparently and realtime. Also, it is possible to prevent the risk factors or prepare the preemptive plans to react on them.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.35-44
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• 2021

The Myanmar rice cycle's existing system is still relying on a third party to manage every rice data information from several organizations. It is inconvenient to supervise simultaneously due to the unreliability of information provided by organizations. Thus, the rice cycle's original data is challenging to be utterly trusted since irresponsible parties can manipulate the current state of information. Moreover, the applied system does not preserve a proper incentive for the involved parties. In this paper, we leverage the Ethereum blockchain to be adopted to tackle the aforementioned issues. The main objective is to build trust between parties in the Myanmar rice cycle system. Our proposed scheme allows customers to check and trace information about the rice cycle information without worrying about the integrity of the data. Furthermore, the authorized parties are also rewarded by the government through Ethereum smart contract features. Eventually, our scheme achieves traceability in the rice chain system and leads to the complete digitization and automation of the rice cycle information.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.195-201
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• 2022

For a efficient distance education environment, the need for correct problem recommendation guides considering the learner's exact learning pattern is increasing. In this paper, we study block chain based smart contract technology to suggest a method for presenting the optimal problem recommendation path for individual learners based on the data given by situational weights to the problem patterns of learners collected in the distance education environment. For the performance evaluation of this study, the learning satisfaction with the existing similar learning environment, the usefulness of the problem recommendation guide, and the learner data processing speed were analyzed. Through this study, it was confirmed that the learning satisfaction improved by more than 15% and the learning data processing speed was improved by more than 20% compared to the existing learning environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.259-265
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• 2018

As the supply method of products has become diverse and complex, problems such as manipulation of origin and product trace have occurred in the existing supply chain system. In order to deal with these issues, various Blockchain based studies have been actively carried in the SW industry and academy. However, there is a lack of comprehensive survey research on the applied Blockchain techniques, so that it hardly understand the pros and cons of the technologies. In this study, we intensively investigated the diverse studies from the Industrial and academic area based on the several criteria such as the goals, use of key Blockchain technologies, and IoT technologies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.290-292
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• 2019

Since the advent of blockchain and bitcoin, decentralization has been accelerating around the world as a public blockchain ethereum with smartcontract has begun. Developers can use Ethereum's blockchain development platform to develop "distributed applications" (DApp) running on a decentralized P2P network, and various types of devices from IoT to mobile can participate in a block-chain distributed environment have. Using Ethereum's blockchain development platform, developers can develop "Decentralized Application (DApp)" that run on a decentralized P2P network and various types of devices from IOT to mobile can participate in distributed blockchain environments. There are many ways to interact with the blockchain and the smart contract, but users tend to prefer the mobile methods due to their convenience and accessibility advantages. Therefore, the author developed an Android based voting DApp and researched related issues. Since the current development methods of DApp are not adequately researched and standardized, efficient methods for developing user-friendly DApp were studied. Because DApp has to spend a certain amount of fees to interact with blockchain, it has intensively investigated the gas problem of Smart Contract code and the security problem of code, and author would like to introduce it in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.277-278
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• 2023

Smart contract는 Off-chain 데이터를 On-chain에서 조회해보지 못하는 "Blockchain Oracle Problem"을 갖고 있다. Oracle Problem을 적용할 때 실제 사용자 측면에서 어떠한 비용이 발생하는지 연구가 부족하다고 느껴, Chainlink 오라클 아키텍처 기반 시스템의 On-chain 비용을 측정할 수 있는 식을 제안한다. 그 결과 각 아키텍처마다 gas fee, oracle fee, latency의 차이를 확인한다.

• Journal of the Korea Society of Computer and Information
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• v.23 no.10
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• pp.73-80
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• 2018

The shared economy began with the concept of sharing the physical and intellectual assets of individuals with others. Nowadays, the concept of shared economy is becoming one of the industries as an enterprise type. Especially, with the development of the Internet and smart devices, various forms of shared economy have been developed in accordance with the need of sharing of individual income. Digital content is also a shareable commodity and it is seeking to utilize it as an item of shared economy. Accordingly, when digital contents are used as a shared economy, there are various possible threats -security threats that may arise in the course of transactions, potential for theft, alteration and hacking of contents. In this paper, we propose transaction method and content protection method using block chain-ethereum technology to reduce security threats and transparent transactions that can occur in digital contents transactions. Through the proposed method, the trust of the consumer and the supplier can be measured and the encryption can be performed considering the characteristics of the data to be traded. Through this paper, it is possible to increase the transparency of smart transaction of digital contents and to reduce the risk of content distortion, hacking, etc.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.255-266
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• 2021

Most common web or application system architectures have central network. As a result, central network can be supervised and controlled in all situation. And It has the advantage of easy to manage and fast to work. However, central network have a disadvantage of weak to security and unclear. In particular, many institutions used by web system be has many problems by central network. In this paper, we proposed blokchain technology based on ethereum to resolve of problem and trading structure that arise in cental network. We propose a decentralized application based on points including cryptocurrency functions and smart contract to the advantages of blockchain with a decentralized structure. The results of the performance experiment are as follows; It has shown the advantages of reliable use and security in a variety of environments(Windows, Ubuntu, Mac).

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.187-199
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• 2018

The purpose of this study is to find out the positive effects of the block chain when applied to the logistics industry and what legal problems should be solved to apply the block chain to the logistics industry. As a result of the study, it was found that the block chain can create the streamlining document work, increasing visibility, improving transaction reliability, activating Internet of things, and expanding smart contract. However, in order to apply the block chain to the logistics industry, have also confirmed that the scope of electronic transactions, international distribution of electronic bill of lading, and legal supplementation related to personal information protection are necessary. It is meaningful to confirm the applicability in the logistics industry, the positive effect and the legal problem, but it is necessary to study the problem from the practical point of view in the hereafter research.