• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.201-208
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• 2010

The classical iterated hash function is vulnerable to a multi-collision attack. Gauravaram et al. proposed 3C and 3C+ hash functions, in which an accumulation chain is added to usual Merkle-Damgard changing. Their goal is to design composition schemes resistant to generic attacks of Joux's type, but Joscak and Tuma have shown that 3C and 3C+ schemes are not better than Merkle-Damgard scheme in term of security against multi-collision attacks under some mild assumptions. In this dissertation, in order to increase security of 3C hash function, we proposed secure double pipe hash function which was effectively using XOR and XNOR operations per blocks of message. We seek to improve on the work of Lucks in a way. Proposed secure double pipe hash function takes resistance to multi-block collision, fixed point and pre-image attacks.

• Journal of Convergence for Information Technology
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• v.9 no.7
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• pp.14-24
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• 2019

It is necessary to look into multiple subjects, such as effectiveness, laws and polices of blockchain in order to easily accept blockchain technology in small and mid-sized enterprises(SME). This study analyzes the positive effects of applying the block chain to SMEs, examines the laws and policies required to apply them, and identifies the tasks. As a result, we confirmed that it can create positive effects such as optimizing supply chain management, simplifying import and export process documents, improving product quality, facilitating flow of funds, and improving transaction reliability. Also, we confirmed that it is necessary to improve the basic law of electronic transaction, electronic commerce law, electronic financial transaction law, personal information protection legislation, and needs policy supplement for platform development, education system for SMEs, transaction standardization guidelines, tax reduction policy, and block chain research and development. More extensive practical research and specific individual legal studies are needed in the future.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.113-120
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• 2017

With the development of virtual reality technology, in recent years, user-friendly hand gesture interface has been more studied for natural interaction with a virtual 3D object. Most earlier studies on the hand-gesture interface are using relatively simple hand gestures. In this paper, we suggest an intuitive hand gesture interface for interaction with 3D object in the virtual reality applications. For hand gesture recognition, first of all, we preprocess various hand data and classify the data through the binary decision tree. The classified data is re-sampled and converted to the chain-code, and then constructed to the hand feature data with the histograms of the chain code. Finally, the input gesture is recognized by MCSVM-based machine learning from the feature data. To test our proposed hand gesture interface we implemented a 'Virtual Block' game. Our experiments showed about 99.2% recognition ratio of 16 kinds of command gestures and more intuitive and user friendly than conventional mouse interface.

• Knowledge Management Research
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• v.21 no.3
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• pp.45-65
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• 2020

It is desirable to invest in wine that increases its value, but wine investment itself is unfamiliar in Korea. Also, the process itself is unreasonable, and information is often forged, because pricing in the wine market is done by a small number of people. With the right solution, however, the wine market can be a desirable investment destination in that the longer one invests, the higher one can expect. Also, it is expected that the domestic wine consumption market will expand through the steady increase in domestic wine imports. This study presents the consortium block chain framework for revitalizing the wine market and enhancing transparency as the "right solution" of the nation's wine investment market. Blockchain governance can compensate for the shortcomings of the wine market because it guarantees desirable decision-making rights and accountability. Because the data stored in the block chain can be checked by consumers, it reduces the likelihood of counterfeit wine appearing and complements the process of unreasonably priced. In addition, digitization of assets resolves low cash liquidity and saves money and time throughout the supply chain through smart contracts, lowering entry barriers to wine investment. In particular, if the governance of the block chain is composed of 'chateau-distributor-investor' through consortium blockchains, it can create a desirable wine market. The production process is stored in the block chain to secure production costs, set a reasonable launch price, and efficiently operate the distribution system by storing the distribution process in the block chain, and forecast the amount of orders for futures trading. Finally, investors make rational decisions by viewing all of these data. The study presented a new perspective on alternative investment in that ownership can be treated like a share. We also look forward to the simplification of food import procedures and the formation of trust within the wine industry by presenting a framework for wine-owned sales. In future studies, we would like to expand the framework to study the areas to be applied.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.553-554
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• 2018

Supply Chain Management (SCM) is the overall process (component procurement, production planning, delivery, inventory control, etc.). It is the process from the supplier to the consumer until the raw material becomes the finished product. Basically, traditional supply chain management is primarily aimed at cost reduction and efficiency. However, considering only cost reduction and efficiency, it is not easy apply the center of 4th industry to Smart Factory. In this study, I propose a form of supply chain management network. It can be satisfy the security by using block chain and automatic control of each element by adding the internet of things.

• Journal of the Korean Applied Science and Technology
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• v.18 no.2
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• pp.118-126
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• 2001

Micelle formation and adsorption at the $Ti0_{2}$ interface of a series of polystyrene-polythylene oxide(PS-PEO) block copolymer in aqueous solution was studied using fluorescence probing and small-angle X-ray methods. Further, the stability of aqueous $Ti0_{2}$ dispersion in the presence of copolymer was investigated by microelectrophoresis, optical density and sedimentation measurements. The dissolution of pyrene as fluorescent probe in aqueous surfactant solution leads to a slow decrease of the $I_{1}/I_{3}$ ratio, as the copolymer concentration increase; $I_{1}$ and $I_{3}$ are respectively the intensities of the first and third vibrionic peaks in the pyrene fluorescence emission. The behaviour was due to the characteristics of the copolymers and/or to the copolymer association efficiency in water. Moreover, the adsorption at the plateau level increases with decreasing PEO until chain length. The zeta potential of $TiO_{2}$ particles decreases with increasing copolymer concentration and reaches a plateau value. Finally, stabilization using block copolymers was more effective with samples having higher weight fractions of PS block.

• Macromolecular Research
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• v.17 no.5
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• pp.313-318
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• 2009

The side chain liquid crystal triblock copolymers (TBCs), which underwent phase transitions below their decomposition temperature, were prepared by copolymerization of poly(n-butyl acrylate) and a comonomer containing the mesogenic azobenzene group. The physical properties of TBCs in the distinctive transition temperature ranges were investigated in terms of the liquid crystal (LC) content in the copolymers. The phase transition temperatures traced optically, thermally and rheologically were well coincided one another and clearly exhibited the phase transition of smectic-nematic-isotropic with increasing temperature. In the smectic phase, increasing temperature made the liquid crystal system more elastic, but viscosity (${\eta}'$) remained almost constant. In the nematic phase, increasing temperature abruptly decreased ${\eta}'$ and G', ultimately leading to isotropic phase. Both smectic and nematic phases exhibited Bingham viscosity behavior but the former gave much greater yield stress at the same LC content.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.254-256
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• 2004

Polymerase chain reaction (PCR) is a powerful tool for precisely amplifying selected DNA sequences that have had a broad impact on genomic studies. When examining human $\alpha$- and $\beta$- tryptase genes which have 95% DNA homology, inconsistent PCR amplification of genomic sequences hampered our progress. This study suggests that long PCR technique on the original DNA digested with restriction enzymes improves both efficiency and sensitivity of PCR. These improved results seem to derived from the effective denaturation of the original genomic DNA template or reduction of formation of secondary structures that block either primer annealing or extension in PCR. Elimination of homo- or hetero-duplex products derived from highly homologous genes provides an additional advantage in this study. This communication describes how the use of restriction enzymes improved these efficiencies, and also facilitated studies of highly homologous genes including tryptase genes.

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.92-92
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• 2017

• The Korean Journal of Pain
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• v.5 no.1
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• pp.108-112
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• 1992

Pain from pelvic cancer is very difficult to manage because it's vague ness and bilateral nature. Furthermore, nerve blocks in this area are dangerous because sensory afferent nerves from pelvic viscera are adjacent to nerves that regulate bowel and bladder control, and motor nerve of lower extremities'. Bilateral lumbar sympathectomy has been used for malignant pelvic pain with little risk of neurologic complication. However it is not a specific block for pelvic visceral pain, because the lumbar sympathetic chain does not innervate pelvic viscera in a direct manner. Therefore the potentials of lumbar sympathectomy for pelvic visceral pain are attributed to caudad diffusion of neurolytic agents to the smperior hypogastric plexus. I have experienced 3 cases of superior hypogastric plexus neurolysis per se without any significant complications.