• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.115-121
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• 2019

I analyzed the structure of a block-chain system and a block-chain-based service system. It is a decentralized book encryption system software technology that does not require a third party to secure trust between the two parties. Block chains are structured in a linked list structure. The block chain manage transaction information by blocking the transaction information, in conjunction with other blocks. As a result, I have discovered structural weaknesses in current block-chain systems and block-chain-based service systems. Once these possible structural problems are resolved, I expect that the block-chain-based service system will make various industrial contributions.

• 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.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.195-201
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• 2019

This paper proposes a blockchain system to share Wireless Local Area Network (WLAN) that recently suffers from mutual interference among increasing devices using unlicensed bands. Blockchain technology can induce cooperation from users by incentivizing them with cryptocurrency like shown in Bitcoin example. In this paper, we describe Blockchain based access mechanism in WLAN instead of conventional authentication based access. Here, users can access any WLAN access point by paying through smart contract while they also receive payment from others. In order to support real-time transaction, we apply proof-of-authority that is realized by Byzantine fault tolerant protocol instead of well-known proof-of-work that requires huge computing power and delay.

• Journal of Arbitration Studies
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• v.8 no.1
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• pp.323-352
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• 1998

Documentary letters of credit including standby letters of credit are governed by the independence or abstraction rule and the doctrine of strict compliance. Since the former rule requires the issuing bank to honor the drafts regardless of the defective performance of the underlying contract, the applicant(the customer) will be without a remedy if he is unable to make himself whole by litigation on the underlying contract. Therefore, the applicant is exposed to a risk much higher than in the commercial letters of credit. The Uniform Customs and Practice for Documentary Credit(UCP) has no provisions allowing legal relief for the applicant on the abuse of L/C by unscrupulous beneficiary, but UCC ${\S}5-114$ has provision allowing injunctive relief for the applicant. In this paper, I attempted to clarify certain standards of injunctive relief available for the customer in the credit. When there is fraud in the L/C transaction by any of the parties concerned, we must weigh the principle of independence or abstraction and the fraud rules. According to banking practice and judicial precedence, we need not keep the principle of independence and abstaction even in fraudulent transaction and the bona fide sufferer must be protected. The purpose of this paper is to review the studies of Fraud rule and the Injunction and to suggest the applicable standards for the Injunction therory under letters of credit. Specially this paper analysed the following ; (1) the guideline for the fraud (exception) rule to the autonomy principle, (2) the appilcable standards of the Injunction, and (3) the implications on parties concerned in letters of credit transaction. Conclusively, the Injunction should be granted if (1) there is clear proof of fraud (2) the fraud constitutes fraudulent abuse if the independent purpose of L/C (3) irreparble injury might follow if injunction is not granted or the recovery of damages would be seriously endangered.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.11-16
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• 2022

Efforts to incorporate blockchain into various fields are continuing as cryptocurrency transactions become more active. Blockchain has the characteristic that once recorded facts cannot be modified or deleted. Due to these characteristics, the use in the field of recording and proving certain facts, such as voting or proof of ownership, is attracting attention. In this paper, users who want to participate in the transaction process using private blockchain, one of the types of blockchain, are divided into real estate brokers, building owners, and purchasers (lessors), and roles are assigned to each user. In addition, we would like to propose a system to increase reliability through the participation of institutions. Through this, we intend to not only present a real estate transaction system that prevents damage from real estate fraud related to false sales and fraudulent contracts, but also enhances reliability and contributes to finding ways to utilize blockchain in the future.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.108-114
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• 2002

This paper describes the design of a robust adaptive controller for a nonlinear dynamical system with unknown nonlinearities. These unknown nonlinearities are approximated by multilayered neural networks (MNNs) whose parameters are adjusted on-line, according to some adaptive laws far controlling the output of the nonlinear system, to track a given trajectory. The main contribution of this paper is a method for considering input constraint with a rigorous stability proof. The Lyapunov synthesis approach is used to develop a state-feedback adaptive control algorithm based on the adaptive MNN model. An overall control system guarantees that the tracking error converges at about zero and that all signals involved are uniformly bounded even in the presence of input saturation. Theoretical results are illustrated through a simulation example.

• Journal of Information Processing Systems
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• v.14 no.1
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• pp.101-128
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• 2018

Thanks to its potential in many applications, Blockchain has recently been nominated as one of the technologies exciting intense attention. Blockchain has solved the problem of changing the original low-trust centralized ledger held by a single third-party, to a high-trust decentralized form held by different entities, or in other words, verifying nodes. The key contribution of the work of Blockchain is the consensus algorithm, which decides how agreement is made to append a new block between all nodes in the verifying network. Blockchain algorithms can be categorized into two main groups. The first group is proof-based consensus, which requires the nodes joining the verifying network to show that they are more qualified than the others to do the appending work. The second group is voting-based consensus, which requires nodes in the network to exchange their results of verifying a new block or transaction, before making the final decision. In this paper, we present a review of the Blockchain consensus algorithms that have been researched and that are being applied in some well-known applications at this time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1266-1285
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• 2022

Compact E-cash is the first scheme which can withdraw 2^l coins within 𝒪(1) operations and then store them in 𝒪(𝑙) bits. Because of its high efficiency, a lot of research has been carried out on its basis, but no previous research pay attention to the privacy of payees and in some cases, payees have the same privacy requirement as payers. We propose a double-blind compact E-cash scheme, which means that both the payer and the payee can keep anonymous while spending. In our scheme, the payer and the bank cannot determine whether the payees of two different transactions are the same one and connect the payee with transactions related to him, in this way, the privacy of the payee is protected. And our protocols disconnect the received coin from previous transaction, then, the coin can be transferred into an unspent coin which belongs to the payee. The proposed e-cash scheme is secure within y-DDHI and LRSW assumption.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.143-151
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• 2008

74% of Internet users use the UCC, and You Tube using firearms in a crime occurred. Internet crime occurred in the online, non-face transaction, anonymous, encapsulation. In this paper, we are studied a Network Forensic Way and a technique analyze an aspect criminal the Internet haying appeared at Internet UCC, and to chase. Study ID, IP back-tracking and position chase through corroborative facts collections of the UCC which used UCC search way study of the police and a public prosecutor and storage way and network forensic related to crimes of Internet UCC. Proof data encrypt, and store, and study through approach control and user authentication so that they are adopted to legal proof data through integrity verification after transmission and storages. This research via the Internet and criminal conspiracy to block the advance promotion, and for the criminal investigative agencies of the Internet will contribute to the advancement forensics research.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.12
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• pp.133-162
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• 1999

The international sale transaction is in essence a sale of goods and presents all those commercial and legal problems in any sale of goods. As a result, A International sales contract imposes several duties on the parties : the seller must deliver the goods and transfer ownership in them, while the buyer must pay the price and take delivery of the goods. However, there are several problems which impede a active transaction between seller and buyer who have their places of business in other countries each other. Therefore, It is necessary to provide the concept on the conformity of goods in the Int'l Sale of Goods. Especially, In our consideration for the point of time when defects occurs, the existence of non-conformity of goods should be judged on the basis of time of delivery rather than time of contract. Moreover, The burden of proof about nonconformity of goods is another fact which make an international dispute between the contractual parties in an international trade. Thus, The consistency in the interpretation of law must be maintained betweened the warranty and seller's liability. In the Uniform Commercial Code and UN Convention, non-conformity of contract is made of contract liability. And in our civil and commercial law provisions of warranty should be understand as the special ones of the provisions of general non-performance of obligation liability. As a result, More concrete study of them is required because they may have a great influence especially on international trade. As a result, We should be our best in finding a helpful and systematic structure that the dualistic structure of nonperformance of obligation liability and warranty liability must be unified by studying the theories of English and American warranty and our legal system, as well as international practice and usage being used in an international trade.