• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.211-218
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• 2020

Recently, with the advent of blockchain technology, attempts to apply this technology to existing systems are increasing. By using the blockchain technology consensus ledger and smart contract, it is necessary to distribute certificates to various fields that require documents, attestation, authentication, verification, etc. We are studying methods using hash operation, blockchain, etc., but it is difficult to spread the technology as it has not yet reached the stage of commercialization. In this paper, user device registration authentication algorithm, blockchain-based question and answer authentication algorithm, certificate issuance, verification process and encryption algorithm, and server-side authentication for easy application in blockchain based business platform environment We proposed a blockchain-based system authentication method using four algorithms.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.2
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• pp.107-116
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• 2016

Premature babies of less than 37 weeks gestation might require oxygen therapy as an integral part of treatment and respiratory support. Because of their under-developed lungs, these so-called "preemies" might contract respiratory distress syndrome (RDS). To treat RDS, neonatal oxygen therapy is administered, where controlled oxygen gas is measured as a fraction of inspired oxygen ($FiO_2$). However, exposure to high oxygen content during long treatment could cause oxygen intoxication, which might cause permanent blindness due to retinopathy of prematurity (ROP), whereas insufficient oxygen exposure could cause severe hypoxia. A doctor would use oxygen saturation ($SpO_2$) data and prescribe a dose of $FiO_2$ to maintain $SpO_2$ within a suitable range. One objective is to maintain $SpO_2$ within the acceptable range using $FiO_2$ that is as low as possible. Adjustment of $FiO_2$ would normally be done by nurses every 15 to 30 minutes, which might not be safe in many situations. An error in $FiO_2$ adjustment during a manual procedure could be as large as +/- 2.5%. This paper presents a system that can determine an $FiO_2$ value suitable to the current $SpO_2$ and that automatically adjusts $FiO_2$ with an error clearance of +/- 0.25%.

• Journal of Information Technology Applications and Management
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• v.26 no.6
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• pp.79-87
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• 2019

Blockchain is a distributed network in a decentralized P2P infrastructure. In this paper, we propose and implement a blockchain-based pet trade service DApp(Decentralized Application). In the existing trading services, there is no way to know the status of dogs in interpersonal transactions and an additional distribution cost has been incurred. As a solution to this problem, we introduce a blockchain technology for a pet trade service where users can check whether an individual pet is healthy or not by its registered biometric data in order to have an efficient and confident trade service. The registered users can purchase puppies or registering information for their dogs to sell through a pet trade service DApp. It is also possible to make a reliable trade by verifying whether the dog is actually the same one through an inscription information of a dog.

• Smart Structures and Systems
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• v.6 no.3
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• pp.239-262
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• 2010

Tube Lines has carried out a "knowledge and investigation programme" on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a "wish-list". Assessment reports have now been produced for all assets forming Tube Lines' deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.

• Smart Structures and Systems
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• v.21 no.2
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• pp.249-255
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• 2018

Many studies in risk management have been focused on management process, contract relation, and risk analysis in the past decade, but very few studies have addressed project risks from the perspective of risk efficiency. This study started with using Fault Tree Analysis to develop a framework for the decision-making support system of risk management from the perspective of risk efficiency, in order for the support system to find risk strategies of optimal combination for the project manager by the trade-off between project risk and cost of project strategies. Comprehensive and realistic risk strategies must strive for optimal decisions that minimize project risks and risk strategies cost while addressing important data such as risk causes, risk probability, risk impact and risk strategies cost. The risk management in the construction phase of building projects in Taiwan upon important data has been analyzed, that provided the data for support system to include 247 risk causes. Then, 17 risk causes were extracted to demonstrates the decision-making support system of risk management from the perspective of risk efficiency in building project of Taiwan which could reach better combination type of risk strategies for the project manager by the trade-off between risk cost and project risk.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.4
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• pp.298-305
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• 2020

This paper deals with the implementation of electronic voting system using permissioned block chain technology. Cases studies have recently been under way in many industrial areas to review the application of the blockchain based electronic voting system. The existing electronic voting system was easily exposed by hacking because of its centralized characteristics, making it difficult to ensure the reliability and transparency of the voting system itself. In this study, we proposed key considerations and concepts to ensure the reliability and transparency of voters and voting stakeholder by utilizing a hyperledger fabric which is nowadays widely used as a permissioned blockchain.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.82-84
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• 2018

본 논문은 이더리움 네트워크에 트랜잭션 발행 시 발생하는 부하(비용)을 줄이기 위해 스마트 콘트랙트를 효율적으로 구성하는 방식에 대해 연구한다. 이더리움 네트워크에 부하를 줄이기 위해서는 발생되는 트랜잭션의 양도 중요하지만 발생하는 트랜잭션의 크기가 작은 효율적인 스마트 콘트랙트 배포와 간단한 구조를 가진 함수를 호출하는 것도 중요하다. 그렇기 때문에 이더리움 스마트 콘트랙트의 구조에 따른 성능 평가를 진행하여 최적의 성능을 보이는 스마트 컨트랙트 구성 방법에 대해 연구를 진행한다. 최적의 성능은 동일한 데이터를 넣을 수 있는 상황에 대해 평가하며 평가 방식은 데이터를 블록체인에 저장 할 때 발생하는 가스 비용 비교를 통해 결정한다. 스마트 콘트랙트의 성능 평가 항목으로는 콘트랙트 배포와 함수 호출시 데이터의 구조, 개수에 따른 가스 비용의 비교 분석을 통해 최저의 가스 비용으로 함수 호출 및 스마트 콘트랙트 생성 및 배포 시키는 구조에 대해 연구를 진행한다.

• Journal of Information Processing Systems
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• v.16 no.4
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• pp.760-773
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• 2020

When a crime occurs, the information necessary for solving the case, and various pieces of the evidence needed to prove the crime are collected from the crime scene. The tangible residues collected through scientific methods at the crime scene become evidence at trial and a clue to prove the facts directly against the offense of the suspect. Therefore, the scientific investigation and forensic handling for securing objective forensic in crime investigation is increasingly important. Today, digital systems, such as smartphones, CCTVs, black boxes, etc. are increasingly used as criminal information investigation clues, and digital forensic is becoming a decisive factor in investigation and trial. However, the systems have the risk that digital forensic may be damaged or manipulated by malicious insiders in the existing centralized management systems based on client/server structure. In this paper, we design and implement a blockchain based digital forensic management model using Hyperledger Fabric and Docker to guarantee the reliability and integrity of digital forensic. The proposed digital evidence management model allows only authorized participants in a distributed environment without a central management agency access the network to share and manage potential crime data. Therefore, it could be relatively safe from malicious internal attackers compared to the existing client/server model.

• Journal of Information Processing Systems
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• v.17 no.5
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• pp.989-1003
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• 2021

With the recent increase in the types of services provided by Internet companies, collection of various types of data has become a necessity. Data collectors corresponding to web services profit by collecting users' data indiscriminately and providing it to the associated services. However, the data provider remains unaware of the manner in which the data are collected and used. Furthermore, the data collector of a web service consumes web resources by generating a large amount of web traffic. This traffic can damage servers by causing service outages. In this study, we propose a website search engine that employs a system that controls user information using blockchains and builds its database based on the recorded information. The system is divided into three parts: a collection section that uses proxy, a management section that uses blockchains, and a search engine that uses a built-in database. This structure allows data sovereigns to manage their data more transparently. Search engines that use blockchains do not use internet bots, and instead use the data generated by user behavior. This avoids generation of traffic from internet bots and can, thereby, contribute to creating a better web ecosystem.