• Title, Summary, Keyword: Block Chain

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A Study on Contract Management Platform Based on Blockchain (블록체인 기반의 계약관리 플랫폼 연구)

  • Kim, Sunghwan;Kim, Younggon
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.19 no.3
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    • pp.97-103
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    • 2019
  • Electronic contract systems are widely used to integrate and manage the contract management process based on the development of ICT technology. Recently, improvement methods using block chain technology are being studied. However, contract management systems have processing performance, security vulnerabilities, data entry, and service accessibility issues. In this paper, we propose a block - chain based contract management platform with block chain, smart contract, and Rest API. The suggested platform includes the RPBFT algorithm which solves the processing performance and security vulnerability of the existing consensus authentication algorithm, and the algorithm to prevent data entry and enhance transparency of participants. The block-chain-based contract management platform proposed in this paper provides a use environment with improved processing performance, security, reliability, and transparency, and can be used through API without burdening construction. Therefore, The effect can be expected.

The study of Defense Artificial Intelligence and Block-chain Convergence (국방분야 인공지능과 블록체인 융합방안 연구)

  • Kim, Seyong;Kwon, Hyukjin;Choi, Minwoo
    • Journal of Internet Computing and Services
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    • v.21 no.2
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    • pp.81-90
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    • 2020
  • The purpose of this study is to study how to apply block-chain technology to prevent data forgery and alteration in the defense sector of AI(Artificial intelligence). AI is a technology for predicting big data by clustering or classifying it by applying various machine learning methodologies, and military powers including the U.S. have reached the completion stage of technology. If data-based AI's data forgery and modulation occurs, the processing process of the data, even if it is perfect, could be the biggest enemy risk factor, and the falsification and modification of the data can be too easy in the form of hacking. Unexpected attacks could occur if data used by weaponized AI is hacked and manipulated by North Korea. Therefore, a technology that prevents data from being falsified and altered is essential for the use of AI. It is expected that data forgery prevention will solve the problem by applying block-chain, a technology that does not damage data, unless more than half of the connected computers agree, even if a single computer is hacked by a distributed storage of encrypted data as a function of seawater.

Synthesis of Low Molecular-weight Poly (Propylene Carbonate)-Poly (Ethylene Glycol) Block Copolymers through $CO_2$/Propylene Oxide Copolymerization (이산화탄소/프로필렌 옥사이드 공중합을 통한 저분자량 폴리(프로필렌 카보네이트)-폴리(에틸렌 글리콜) 블록 공중합체의 합성)

  • Lee, Sang-Hwan;Cyriac, Anish;Jeon, Jong-Yeob;Lee, Bun-Yeoul
    • Clean Technology
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    • v.17 no.3
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    • pp.244-249
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    • 2011
  • We synthesized low molecular-weight polymers bearing hydrophobic and hydrophilic parts in a chain through $CO_2$/propylene oxide copolymerization. When hydrophilic poly (ethylene glycol) bearing -OH group (s) at the end group (s) was added as a chain transfer agent in the $CO_2$/propylene oxide copolymerization catalyzed by a highly active catalyst, block polymers were formed. If poly (ethylene glycol) (PEG) bearing -OH group only at an end was fed, PEG-block-PPC diblock copolymer was obtained. When PEG bearing -OH group at both ends was fed, PPC-block-PEG-block-PPC triblock copolymer was obtained. We confirmed formation of block copolymers by $^1H$-NMR spectroscopy and GPC studies.

A Study on the Application of Block Chain Ethereum Technology to Activate Digital Contents Trading as Sharing economy - data encryption and modify merkle tree-

  • Min, Youn-a;Baek, Yeong-Tae
    • 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.

Modelling Heterogeneity in Fertility for Analysis of Variety Trials (밭의 비옥도를 고려한 품종실험 분석)

  • 윤성철;강위창;이영조;임용빈
    • The Korean Journal of Applied Statistics
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    • v.11 no.2
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    • pp.423-433
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    • 1998
  • In agricultural field experiments, the completely randomized block design is often used for the analysis of variety trials. An important assumption is that every experimental unit in each block has the some fertility. But, in most agricultural field experiments there often exists a systematic heterogeneity in fertility among the experimental units. To account for the heterogeneity, we propose to use the hierarchical generalized linear models. We compare our analysis of the data from Scottish Agricultural colleges list with that using Markov chain Monte Carlo method.

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Isothermal Crystallization Behavior of PCL-PPG-PCL Triblock Copolymers (PCL-PPG-PCL 3블록 공중합체의 등온결정화 거동)

  • 김영호;장진성
    • Textile Science and Engineering
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    • v.34 no.11
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    • pp.784-792
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    • 1997
  • A new method for the estimation of the initial portion of the crystallization exotherm, normally obscured due to the response time of the DSC in the case of fast crystallization, was developed. This method allowed a more accurate analysis of the DSC isothermal crystallization data. Poly(propylene glycol)(PPG)-poly($\varepsilon$-caprolactam) (PCL)-PPG triblock copolymers with various PPG contents were synthesized via anionic copolymerization of $\varepsilon$-cairo-lactam and the macroactivators which contain PPG units. Isothermal crystallization behaviors of the synthesized block copolymers were allalyzed with Avrami equation by using above-mentinned non-linear curve fitting program and conventional Avraml plot. At PPG contents greater than 10%, the overall crystallization rate decreased because of the uncrystallizable PPG unit. The induction time for crystallization increased, and the ratio of primary crystallization to overall crystallization increased at the same degree of undercooling. On the other hand, crystal growth rate increased with PPG content. The presence of PPG unit in the block copolymer has two opposing effects on crystallization. First, as the amount of PPG unit increases it interferes with nucleation. As a result the induction time for crystallization increases and the crystallization rate decreases. Secondly, it increases the mobility of the block copolymers because of the ether linkage and allows faster diffion of the copolymer chain to the crystal surface. Consequently the crystal growth rate after nucleation increases. Between the two effects the first one seems to be dominating and the overall crystallization rate decreases with increasing PPG content in block copolymers. Furthermore there are some different crystallization behaviors between the block copolymers and PCL homo polymer. Nucleation of block copolymers of PPG content up to 10% occurs faster than in the case of homo PCL because small amounts of PPG unit may act as heterogeneous nuclei. Also the chain mobility increased with the introduction of PPG unit, therefore the overall crystallization rate was faster than homo PCL. But if the PPG content exceeds 10% the overall crystallization rate of the block copolymers becomes slower than homo PCL.

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Development of an FTA origin information management system prototype utilizing private block chain (프라이빗 블록체인 활용 FTA원산지 정보관리 시스템 프로토타입 개발)

  • Cho, Hyung-Min;Kim, Jong-Hyun;Lee, Kyung-Hee
    • The Journal of Bigdata
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    • v.4 no.1
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    • pp.1-10
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    • 2019
  • As FTA is spreading, it is becoming more and more necessary to improve the accuracy and reliability of the country of origin information at the domestic trading stage in preparation for the actual surveys expected to surge in the near future. However, there are many problems in collecting and managing information related to origin. It is pointed out that the shortage of export-oriented profits and the incentive for issuance of FTA-related profits, as well as the lack of information on the distribution and management of origin information of domestic manufacturing companies are also pointed out as important causes. In this paper, we propose a method to improve the efficiency of management and circulation of smooth FTA origin (comprehensive) certificate of Korean companies and to improve reliability through manipulation prevention by building prototype of origin information management system based on private block chain Hyperledger. The block chain, called Distributed Ledger or Trusted Internet, provides a technical infrastructure that enables various related companies to distribute origin information with high reliability and immediate distribution in the supply chain, but research on its application is still in the beginning stage.

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A Study on Smart Contract for Personal Information Protection (개인정보보호를 위한 스마트컨트랙트 연구)

  • Kim, Young-Hun
    • Journal of Digital Convergence
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    • v.17 no.3
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    • pp.215-220
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    • 2019
  • The block chain technology is a technique that prevents manipulation of data and ensures integrity and reliability. Ethereum is building a smart contract environment as a type of encryptionenabled system based on block chains. Smart contracts can be implemented when conditions are met, thus increasing confidence in digital data. However, smart contracts that are being tried in various ways are not covered by information security and personal information protection. The structure in which the network participant can view the open transaction ledger is exposed to data or personal information listed in the block chain. In this study, it is possible to manage the data of personal information recorded in the block chain directly. This study is protected personal information by preventing the exposure of personal information and by executing time code, it is possible to erase recorded information after a certain period of time has elapsed. Based on the proposed system in the future, it is necessary to study the additional management techniques of unknown code defects or personal information protection.

A Design of Hadoop Security Protocol using One Time Key based on Hash-chain (해시 체인 기반 일회용 키를 이용한 하둡 보안 프로토콜 설계)

  • Jeong, Eun-Hee;Lee, Byung-Kwan
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.10 no.4
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    • pp.340-349
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    • 2017
  • This paper is proposed Hadoop security protocol to protect a reply attack and impersonation attack. The proposed hadoop security protocol is consists of user authentication module, public key based data node authentication module, name node authentication module, and data node authentication module. The user authentication module is issued the temporary access ID from TGS after verifing user's identification on Authentication Server. The public key based data node authentication module generates secret key between name node and data node, and generates OTKL(One-Time Key List) using Hash-chain. The name node authentication module verifies user's identification using user's temporary access ID, and issues DT(Delegation Token) and BAT(Block Access Token) to user. The data node authentication module sends the encrypted data block to user after verifing user's identification using OwerID of BAT. Therefore the proposed hadoop security protocol dose not only prepare the exposure of data node's secret key by using OTKL, timestamp, owerID but also detect the reply attack and impersonation attack. Also, it enhances the data access of data node, and enforces data security by sending the encrypted data.