• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.1-6
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• 2020

Recently, epidemic of covid-19 causes rapid increase in demand for untact video conferences. In existing server-client based video conference systems such as Zoom, Google Meet, etc., the server generates the conference key and controls the access rights of meeting members and their contents with it. In this case, the server can fabricate or repudiate the meeting. So, the privacy of the meeting members is not guaranteed. It's necessary to make the conference key distribution scheme where all participants can verify the trustfulness without help of the server. The smart contract is the program stored to the blockchain. Its contents cannot be altered due to the property of the blockchain, and everybody can verify the execution results of it. In this study, we propose the smart contract based conference key distribution scheme. The proposed scheme is consisted of smart contract deployment, conference key generation and verification stages. The smart contract replaces the role of existing trustful server and the meeting members can generate the conference key according to the protocols implemented on it. The proposed scheme can be applied to the video conference systems and only the meeting members can access the conference key.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.235-246
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• 2023

In the rapid technological development of artificial intelligence (AI), electric vehicles, and robots based the fourth industrial revolution, semiconductors determine the core performance, and semiconductor competitiveness is directly related to national competitiveness. However, the Korean semiconductor industry has continuously weakened its competitiveness in the system semiconductor field, excluding memory semiconductors, so in this study, a new smart contract basedblockchain business model to engage the global market, which is the most urgent need for the growth of Korean fabless system semiconductor industry in recession. F-SBM (Fabless-Smart contract based Blockchain Model) proposed. In this study, through the new F-SBM, it was verified how to engage new customers for fabless firms through smart contract based consortium blockchain regarding technology, economy, and reliability items of fabless. This model has great significance in improving the high entry barriers to engaging new customers for the long-cherished desire of the Korean fabless system semiconductor industry and deriving new growth solutions.

• Journal of Software Engineering Society
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• v.28 no.2
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• pp.1-6
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• 2019

There are various stakeholders in the blockchain ecosystem. Since the emergence of Ethereum, many transactions have been made using smart contracts, and a wider range of stakeholders are participating, including not only developers, but also investors, banks, companies, and general users. However, various stakeholders have a problem in that it is difficult and complicated to check the state of smart contracts. If it becomes difficult to check the state, the reliability of the smart contract will be lowered and the utilization will be lowered. Also, if the state check is difficult and complicated for the developer, it will be difficult to provide high quality due to the difficulty of testing and debugging the smart contract developed by the developer. In this research, we propose a design and implementation method of the Ethereum Smart Contract State Monitoring System that enables various stakeholders and developers to easily and continuously check the state of smart contracts and analyze them using historical data.

• Journal of Internet of Things and Convergence
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• v.5 no.2
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• pp.21-26
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• 2019

Wisdom contents is made by an ordinary person and contains life tips helpful in general. As the existing copyright management systems are designed for the corporate or professional authors, it's not easy to use and requires high cost for the ordinary person to get the copyright. Blockchain based system can notarize the block of transactions without help of trustful third party such as existing copyright protection center. Thus, blockchain based copyright protection model is needed to protect the ordinary author's copyright. In this study, we propose the smart contract based copyright protection model which run on the blockchain network. The proposed model consists of smart contract creation, contents purchase and profit sharing stages. The digital signature scheme is used to get the contract agreed by the seller and the author. The smart contract stores the author information, contents information and the percentage of the share as states. If the contents is sold, the sales tokens are redistributed to the author and the seller according to the share. The proposed model can be applied to the ordinary person's copyright registration and management for Wisdom contents distributed in cafe, blog, YouTube, etc.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.1-11
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• 2018

The Blockchain is a technique that prevents data from being manipulated and guarantees the integrity and reliability of the data by all participants in the network jointly owning and validating the data. Since the Blockchain characterized by security, scalability and transparency, it is used in a variety of fields including logistics, distribution, IoT and healthcare, including remittance. In particular, there is a growing interest in smart contract that can create different forms of contracts and automate implementation based on Blockchain. Smart Contract can be used to pre-programme contracts and are implemented immediately when conditions are met. As a result, digital data can be more reliable. In this paper, we are conducting a study on the smart contract design as a way to solve such problems as illegal misuse of funds on virtual currency, which has become an issue recently. Through this process, we applied the customer identification and money laundering prevention process using smart contract, and then check the possibility of preventing money laundering and propose the ASM (AML SmartContract Mechant) design.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.74-78
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• 2019

As software becomes larger and network technology develops, the management of distributed data becomes more popular. Therefore, it is becoming increasingly important to use blockchain technology that can guarantee the integrity of data in various fields by utilizing existing infrastructure. Blockchain is a distributed computing technology that ensures that servers participating in a network maintain and manage data according to specific agreement algorithms and rules to ensure integrity. As smart contracts are applied, not only passwords but also various services to be applied to the code. In order to reinforce existing research on smart contract applied to the blockchain, we proposed a dynamic conditional rule of smart contract that can formalize rules of smart contract by introducing ontology and SWRL and manage rules dynamically in various situations. In the previous research, there is a module that receives the upper rule in the blockchain network, and the rule layer is formed according to this module. However, for every transaction request, it is a lot of resources to check the top rule in a blockchain network, or to provide it to every blockchain network by a reputable organization every time the rule is updated. To solve this problem, we propose to separate the module responsible for the upper rule into an independent server. Since the module responsible for the above rules is separated into servers, the rules underlying the service may be transformed or attacked in the middleware. Therefore, the security mechanism using TLS and PKI is added as an agent in consideration of the security factor. In this way, the benefits of computing resource management and security can be achieved at the same time.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.1-10
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• 2021

The purpose of the study is to contribute to the positive development of blockchain technology by providing data to examine security vulnerabilities and threats to blockchain-based services and review countermeasures. The findings of this study are as follows. Threats to the security of blockchain-based services can be classified into application security threats, smart contract security threats, and network (P2P) security threats. First, application security threats include wallet theft (e-wallet stealing), double spending (double payment attack), and cryptojacking (mining malware infection). Second, smart contract security threats are divided into reentrancy attacks, replay attacks, and balance increasing attacks. Third, network (P2P) security threats are divided into the 51% control attack, Sybil attack, balance attack, eclipse attack (spread false information attack), selfish mining (selfish mining monopoly), block withholding attack, DDoS attack (distributed service denial attack) and DNS/BGP hijacks. Through this study, it is possible to discuss the future plans of the blockchain technology-based ecosystem through understanding the functional characteristics of transparency or some privacy that can be obtained within the blockchain. It also supports effective coping with various security threats.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.140-147
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• 2022

In this study, in order to efficiently detect data patterns and outliers in time series data, outlier detection processing is performed for each section based on a smart contract in the data preprocessing process, and parameters for the ARIMA model are determined by generating and reflecting the significance and outlier-related parameters of the data. It was created and applied to the modified arithmetic expression to lower the data abnormality. To evaluate the performance of this study, the normality of the data was compared and evaluated when the parameters of the general ARIMA model and the ARIMA model through this study were applied, and a performance improvement of more than 6% was confirmed.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.73-77
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• 2023

As the DeFi market continues to expand, fraudulent activities using smart contracts have also increased. HoneyPot and Ponzi schemes are well-known frauds that exploit smart contracts. While several studies have demonstrated the potential to detect smart contracts implementing these scams, there has been a lack of research focusing on simultaneously detecting both types of fraud. This paper addresses this gap by harnessing artificial intelligence to conduct experiments for the detection of both HoneyPot and Ponzi schemes. The study employs the CNN (Convolutional Neural Network) model, commonly used for malware detection. To effectively utilize CNN, the bytecode of smart contracts is transformed into visual representations. The experimental results showcase a recall rate of 0.89 and an F1 score of 0.85, indicating promising detection capabilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.110-119
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• 2018

Blockchain technology has been highly evaluated for its contracts (contracts for sale, real estate contracts) because of its excellent security, including integrity and non-repudiation. In a blockchain, these contract services can be developed using a technology called a smart contract, and several blockchain platforms provide a programming language for developing smart contracts. Bitcoin and Ethereum, typical blockchain platforms, provide the Bitcoin Scripts and Solidity languages. Using these programming languages, we can develop the smart contract, a digital contract that can be processed dynamically. Smart contracts are being developed in a variety of areas, but studies of designs based on a blockchain are insufficient. In this paper, we propose a meta-model and a static/dynamic design method based on Unified Modeling Language (UML) for smart contracts based on Ethereum. We propose a method for static design attributes and functions of smart contracts, and propose a technique for designing structures among contracts. Dynamic design proposes a technique for designing deployment, function calls, and synchronization among smart contracts, accounts, and blocks within a blockchain. Experiments verify the validity of the design method by applying the static/dynamic design method through real estate contracts.