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Streptomyces sp . DMCJ-49 균주가 생산하는 α- Amylase 저해제 MB4-03의 분리와 구조분석
염대현,최응칠,김진웅,김병각 한국산업미생물학회 1990 한국미생물·생명공학회지 Vol.18 No.4
Streptomyces sp. DMCJ-49 균주의 배양액으로부터 분리된 α-amylase 저해물질 MB4-03은 그 구조상 질소원자와 methyl기를 포함하는 일종의 직선형 α(1→4) 결합으로 연결된 glucose의 변형된 oligomer 형태로서 구성 단당류는 12 정도로 추정된다. MB4-03, an α-amylase inhibitor was isolated from the culture broth of Streptomyces sp. DMCJ-49 and purified through ion-exchange chromatography, adsorption, and gel filtration. The results of various instrumental analyses showed that the inhibitor was one of oligosaccharides that had glucoses as its major component and that its molecular weight was about 2000. And one methyl group which seemed to be related with the inhibitory activity of this compound was identified. From the CMR spectrum, it was elucidated that this compound was composed of α-D-glucopyranoses which were linked together by α(1→4) bond configuration. As the inhibitory effect of this compound was reduced after incubation with β-amylase, the maltose units was seemed to exist at non-reducing terkminal side of it.
이상행위 탐지 시스템 관점에서의 차량 위치 보안 기법 분석
송호승(Hoseung Song),심상규(Sanggyu Sim),염대현(Dae Hyun Yum) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11
V2X (Vehicle to Everything) system ensures safety by sending BSM (Basic Safety Message) including vehicle information and using the MBD (Mis-Behavior Detection) system which is able to classify abnormal or malicious vehicles. However, as vehicle information is exposed for safety, problems related to privacy and security inevitably arise. In particular, location and travel route privacy has been issued recently and many studies have been conducted to protect vehicle location privacy. The problem of conventional studies is that the privacy solutions did not consider V2X system including MBD. Therefore, this paper summarizes the conventional location privacy solutions and analyzes how MBD affects these solutions In addition, based on this analysis, we propose a location privacy solution with GPS position accuracy which is most suitable for the current V2X security system considering BSM and MBD.
이진우(Jinwoo Lee),조국래(Kookrae Cho),염대현(Dae Hyun Yum) 한국정보보호학회 2018 정보보호학회논문지 Vol.28 No.2
비트코인은 2009년 사토시 나카모토가 제안한 암호 화폐로 중앙 기관 없이 통화가 발행, 관리되는 분산 합의 구조를 가지고 있다. 채굴은 이러한 분산 합의 구조의 중추를 담당하는 작업으로 대기 중인 비트코인의 거래를 블록화하여 비트코인의 블록체인(장부)에 포함시키는 역할을 한다. 블록의 생성에는 컴퓨팅 자원이 필요하기 때문에, 채굴을 담당하는 채굴자에게 보상으로 비트코인이 지급되며, 이 보상을 통해 새로운 비트코인이 발급된다. 비트코인은 2100만개 까지만 발행할 수 있도록 설계되었으며, 인플레이션에 대비하기 위해 채굴 과정에 반감기라는 개념이 도입되었다. 2009년에 50 BTC이었던 보상은 현재 12.5 BTC인 상태이나 채굴 보상의 실제 가치는 더욱 늘어났다. 이는 2017년 1월 12일 기준 1 BTC당 924,000원이던 비트코인이 2017년 12월 10일 기준 16,103,306원이 되어 실질 보상액을 증가시켰기 때문이다. 가격 상승으로 인해 신규 채굴자가 지속적으로 유입되고 있음에도 채굴이 실제로 어느 정도 수익성이 있는지에 대한 연구는 미비한 상태이다. 본 논문에서는 비트코인의 채굴 구조를 살펴보고 비트코인의 채굴에 어느 정도의 수익성을 기대할 수 있는지를 살펴보고자 한다. Bitcoin (BTC) is a cryptocurrency proposed by Satoshi Nakamoto in 2009. Bitcoin makes its transactions with no central authorities. This decentralization is accomplished with its mining, which is an operation that makes people compete to solve math puzzles to include new transactions into block, and eventually block chains (ledger) of bitcoin. Because miners need to solve a complex puzzles, they need a lot of computing resources. In return for miners’ resources, bitcoin network gives newly minted bitcoins as a reward to miners when they succeed in mining. To prevent inflation, the reward is halved every 4 years. For example, in 2009 block reward was 50 BTC, but today, the block reward is 12.5 BTC. On the other hands, exchange rate for bitcoin and Korean Won (KRW) changed drastically from 924,000 KRW/BTC (January 12th, 2017) to 16,103,306 KRW/BTC (December 10th, 2017), which made mining more attractive. However, there are no rigorous researches on the profitability of bitcoin mining. In this paper, we evaluate the profitability of bitcoin mining.