• Journal of the Korea Society of Computer and Information
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• v.27 no.6
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• pp.77-86
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• 2022

Recently, various cryptocurrencies (coins) based on block chains have appeared, and interest in privacy coins, which is an anonymity-based cryptocurrency that values personal information protection, is growing. In this paper, we look at coin abuse cases using privacy coins, and analyze the technology that guarantees the anonymity of 8 mainly traded privacy coins (Monero, Dash, Zcash, BEAM, Grin, Horizen, Verge, and Pirate Chain). We would like to analyze the applied technologies for We present the problems that can occur in these privacy coins, check the technology and each element applied to the privacy coin, and analyze the technical difficulty of the anonymity guarantee technology for the mainly traded coins through this, and Appropriate countermeasures and classification of privacy coins for technical difficulty were presented through the problem. Through this, the standard for re-evaluating the value of the coin according to the application of appropriate technology for the privacy coin can be presented.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.139-146
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• 2020

Cloud computing technology provides economic and efficient system operation and management features to deal with rapidly changing IT technologies. However, this is less used in institutes and companies due to low security of cloud computing service. It is recognized that storing and managing important information, which is confidential in external systems is vulnerable to security threats. In order to enhance security of this cloud computing service, this paper suggests a system and user authentication reinforcement model. The suggested technology guarantees integrity of user authentication information and provides users with convenience by creating blocks for each cloud service and connecting service blocks with chains. The block chain user authentication model offers integrity assurance technology of block chains and system access convenience for SSO users. Even when a server providing cloud computing is invaded, this prevents chained invasions not to affect other systems.

• Fibers and Polymers
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• v.4 no.3
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• pp.114-118
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• 2003

The prepolymer and the final polyurethane (PU) block copolymer were synthesized by reacting 4,4-methylene bis(phenylisocyanate) with poly(tetramethylene glycol) and the prepolymer with 1,4-butanediol as a chain extender, respectively, to investigate the relation between phase separation and it's resulting properties. According to FT-IR data, the phase separation of hard and soft segments in the prepolymer and the PU block copolymer grew bigger by increasing the hard segment content, and the PU showed more dominant phase separation than the prepolymer. The heat of fusion due to soft segments decreased in both the prepolymer and the PU by increasing the hard segment content, whereas the heat of fusion due to hard segments increased in the PU did not appear in the prepolymers. The breaking stress and modulus of the prepolymer increased by increasing the hard segment content, and the elongation at break decreased gradually, and the PU showed the highest breaking stress and modulus at 58% hard segment content. However, the best shape recovery of the PU was obtained at 47% hard segment content due to the existence of proper interaction among the hard segments for shape memory effect. Consequently, the mechanical properties and shape memory effect of the PU were influenced by the degree of phase separation, depending on the incorporation of chain extender as well as the hard segment content.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.569-570
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• 2017

Bitcoin-based blockchain technology provides an infrastructure that enables anonymous smart contracts, low-cost remittances, and online payments. However, the block-chain technology that implements the bitcoin has scalability constraints in tradeoffs between throughput and latency. To solve these problems, the Byzantine fault tolerant block-chain technique has been proposed. This technique improves throughput without increasing latency by selecting a leader and constructing many microblocks that do not contain proofs of work within the existing block by the leader. However, this technique may be less secure than existing techniques in selecting the reader. In this paper, we propose a technique for scalability of the blockchain technology by using microblock technology and parallel execution technique. Within one microblock there is information about several transactions. In the proposed scheme, the throughput of the microblocks can be increased by performing concurrently.

• The Korean Journal of Archival Studies
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• no.60
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• pp.317-358
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• 2019

Blockchain technology has emerged as one of the key technologies of the fourth industrial revolution. Blockchain technology is characterized by being able to verify the authenticity of stored information in a block and whether it is false or falsified, cannot arbitrarily manipulate or delete a particular record, and is capable of transparent audit trail. This study is designed to explore how to apply blockchain technology to record management. For this purpose, we want to approach the code area, the physical area of the blockchain technology, to explore some of the key physical structures, and to derive the applicability of the blockchain technology. By implementing the part of 'Cloud-Record Management System', future record management system model and currently in the process of phasing out step by step, as a modular block chain, I suggest a blockchain network model that can simplify or replace various functions of the current record management process.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.485-492
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• 2014

PURPOSE: This study aimed to examine the pain, range of motion (ROM), upper extremity task performance, and functional levels of patients after rotator cuff repair according to the timing of a closed chain exercise thereby presenting basic data for an effective rehabilitation program. METHODS: The intervention was applied three times per week, one hour per day, for four weeks to 40 participants, 78 of whom had undergone rotator cuff repair. The participants were divided into four groups and assigned to usual general physical therapy and an open chain exercise. Group I consisted of the open chain exercise only. The closed chain exercise was applied to group II after the 4 times, group III after the 7 times, group IV after the 10 times. Measurement were used ROM, visual analogue scale (VAS), box and block test (BBT), and shoulder pain and disability index (SPADI). A one-way analysis of variance was conducted to test differences. RESULTS: There were significant differences in the internal/external rotation between group I and group II. The VAS significantly differed between group II and group I, group III, and group IV. The BBT results of group II and group I were significantly different compared to those of group IV. The SPADI significantly differed between group II and group I and between group II and group IV. CONCLUSION: The closed chain exercise was effective for patients following rotator cuff repair from the second week after active exercise was prescribed, verifying its applicability in rehabilitation programs.

• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.27-35
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• 2020

The purpose of this study is to study the technical implementation methods to prevent problems such as the record of important educational activities of the student life record department or the continuous illegal leakage and manipulation. To this end, in this paper, by applying a private blockchain that can be participated only by a given organization or individual, it prevents outsiders from participating in the block network, and creates legitimate authority by creating two types of block data: student information block and access record block in the life record book. We proposed a block mechanism that can be registered, modified, and accessed only by authorized staff members. As a result, we have prepared an alternative to prevent forgery and alteration of the living records by third parties and to secure the integrity of the living records. If applied to the educational administrative information system, social consensus will be established that the operation and management of the life record book is reliable.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.460-464
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• 2011

Poly(ether-block-amide)(PEBA, $PEBAX^{TM}$) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permeation selectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for $PEBAX^{TM}$-1657 membrane and compare with those obtained for other grade of $PEBAX^{TM}$, $PEBAX^{TM}$-2533. And the organic/inorganic hybrid membranes were prepared using $PEBAX^{TM}$ and TEOS(tetraethoxysilane) by sol-gel process, and gas permeation properties were studied. $PEBAX^{TM}$-2533 membrane exhibited higher gas permeability coefficients than $PEBAX^{TM}$-1657 membrane. This was explained by the increase of chain mobility. The permeability coefficients for $PEBAX^{TM}$/TEOS hybrid membranes were higher than pure $PEBAX^{TM}$ membranes. This results were explained by the reduction of crystallinity of polyamide block by the introduction of TEOS. Ideal separation factor of hybrid membranes does not change much. This might be due to the increase of solubility selectivity.

• Advanced Industrial SCIence
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• v.2 no.2
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• pp.1-8
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• 2023

The goal of the study is to describe blockchain technology as it relates to enhancing supply chains in the retail sector in order to achieve sustainability. This study offers a critical analysis of the possible applications of blockchain technology and smart contracts to supply chain management. This paper explains how Blockchain technology may be used by customers and merchants in a variety of retail business operations to great advantage. By adopting a modified version of the UTUAT model, this study validates the possibility of using blockchain for supply chain management in the retail industry. The study found a significant and positive correlation between behavioral intention and acceptance toward employing block networks in supply chain management in the retail business. The behavior intention (BI) to adopt blockchain technology is significantly influenced by performance expectations, effect expectations, subjective standards, and enabling variables. The performance and effort expectations have a considerable impact on the BI to adopt blockchain in supply chain management.

• 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.