• 제목/요약/키워드: Yeon Ju Hwan

검색결과 326건 처리시간 0.036초

SIOT: Secure Gateway for Internet of Things

  • 김연근;고영환;김민수;장진수;배상욱;노주환;강병훈;박경수;김용대;신승원
    • 정보와 통신
    • /
    • 제34권3호
    • /
    • pp.80-89
    • /
    • 2017
  • 오늘날 사물 인터넷(Internet of Things)은 급속도로 발전하며 인간 생활 곳곳에 다양한 형태로 존재하고 있다. 이들은 대부분 개인 정보 등의 민감한 데이터들을 다루기 때문에 사물 인터넷 환경에 대한 강력한 보안을 필요로 하지만, 현재 사물 인터넷 환경은 비정상적 접근을 허용하거나 업데이트를 통한 펌웨어 변조 등의 많은 보안 취약점들을 가지고 있다. 본 논문에서는 현재 사물 인터넷 환경이 가지는 보안 문제점들을 살펴보고, 이들을 해결하기 위해 딥 러닝 기반의 이상 탐지, 로그 위/변조 탐지, 기기 무결성 검증 등의 다양한 보안 기법들이 집약된 보안 게이트웨이인 SIOT를 제안한다. SIOT는 저성능의 사물 인터넷 기기들이 충분한 보안 기능들을 탑재할 수 없음에 주목하여 다수의 보안 기능들을 효율적으로 통합하여 제공하는 새로운 사물 인터넷 보안 프레임워크로써, 지속되는 사물 인터넷 보안 연구에 큰 기여를 할 것으로 기대한다.

Fluctuation Rates of Phytoplankton Assemblages by Passage through Power Plant Cooling System

  • Kang, Yeon-Shik;Lim, Ju-Hwan;Jeong, Yeon-Tae;Jeon, In-Sung
    • 환경생물
    • /
    • 제30권3호
    • /
    • pp.173-184
    • /
    • 2012
  • In order to investigate the fluctuation rates [FR] of phytoplankton after passage through a cooling system, the standing crops, chlorophyll a concentrations and carbon assimilation number of phytoplankton were surveyed at intake and outlet at Wolsong nuclear power plant [NPP] from July 2006 to June 2008. As a result, the total mean standing crops of phytoplankton were $1.0{\times}10^6\;cells\;L^{-1}$ and $7.3{\times}10^5\;cells\;L^{-1}$ at intake and outlet, respectively. The FR of phytoplankton by passage through the cooling system [PTCS] was 27.0%. Among them, the FR of microplankton and nanoplankton were 34.1% and 12.4%, respectively. In addition, the FR of diatoms and dinoflagellateswere 33.9% and 29.7%, respectively. These results showed the entrainment effects on microplankton and diatoms by PTCS were higher than those of nanoplankton and dinoflagellates. The FR of total chlorophyll a concentrations were 54.4%, and the FR of microplankton, nanoplankton and picoplankton were 58.9%, 38.5%, and 52.4%, respectively. So the entrainment effects on microplankton by PTCS were higher than those of nanoplankton and picoplankton. The mean FR of carbon assimilation number of phytoplankton was 57.6%, and the seasonal variations of FR of carbon assimilation number ranged from 47.5% to 76.8%. Our results indicated that the phytoplankton species responded differently to power plant operating conditions such as elevated temperature, chlorination, and mechanical impacts.

Myristicae Semen Extract Protects Excitotoxicity in Cultured Neuronal Cells

  • Kim, Ji-Ye;Ban, Ju-Yeon;Bang, Kyong-Hwan;Seong, Nak-Sul;Song, Kyung-Sik;Bae, Ki-Whan;Seong, Yeon-Hee
    • 한국약용작물학회지
    • /
    • 제12권5호
    • /
    • pp.415-423
    • /
    • 2004
  • Myristica fragrans seed from Myristica fragrans Houtt (Myristicaceae) has various pharmacological activities peripherally and centrally. The present study aims to investigate the effect of the methanol extract of Myristica fragrans seed (MF) on kainic acid (KA)-induced neurotoxicity in primary cultured rat cerebellar granule neuron. MF, over a concentration range of 0.05 to $5\;{\mu}g/ml$ inhibited KA $(500\;{\mu}M)-induced$ neuronal cell death, which was measured by trypan blue exclusion test and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. MF $(0.5\;{mu}g/ml)$ inhibited glutamate release into medium induced by KA $(500\;{\mu}M)$, which was measured by HPLC. Pretreatment of MF $(0.5\;{mu}g/ml)$ inhibited KA $(500\;{\mu}M)-induced$ elevation of cytosolic calcium concentration $([Ca^{2+}]_c)$, which was measured by a fluorescent dye, Fura 2-AM, and generation of reactive oxygen species (ROS). These results suggest that MF prevents KA-induced neuronal cell damage in vitro.

과산화수소수로 유도된 배양 뇌신경세포손상에 대한 왕머루 잎과 줄기 추출물의 보호효과 (Protective Effect of Vitis amurensis Stems and Leaves Extract on Hydrogen Peroxide-induced Oxidative Neuronal Cell Damage in Cultured Neurons)

  • 김주연;주현수;반주연;송경식;배기환;성연희
    • 한국약용작물학회지
    • /
    • 제17권1호
    • /
    • pp.68-74
    • /
    • 2009
  • Vitis amurensis (VA; Vitaceae) has long been used in oriental herbal medicine. It has been reported that roots and seeds of VA have anti-inflammatory and antioxidant effects. In the present study, the protective effect of ethanol extract from stems and leaves of VA on hydrogen peroxide (${H_2}{O_2}$) (100 ${\mu}M$)-induced neuronal cell damage was examined in primary cultured rat cortical neurons. VA (10-100 ${\mu}g$/ml) concentration-dependently inhibited ${H_2}{O_2}$-induced apoptotic neuronal cell death measured by 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. VA inhibited ${H_2}{O_2}$-induced elevation of intracellular $Ca^{2+}$ concentration (${[Ca^{2+}]}_i$) and generation of reactive oxygen species (ROS), which were measured by fluorescent dyes. Pretreatment of VA also prevented glutamate release into medium induced by 100 ${\mu}M$ ${H_2}{O_2}$, which was measured by HPLC. These results suggest that VA showed a neuroprotective effect on ${H_2}{O_2}$-induced neuronal cell death by interfering with ${H_2}{O_2}$-induced elevation of ${[Ca^{2+}]}_i$, glutamate release, and ROS generation. This has a significant meaning of finding a new pharmacological activity of stems and leaves of VA in the CNS.

Screening of Bacterial Antagonists to Develop an Effective Cocktail against Erwinia amylovora

  • Choi, Dong Hyuk;Choi, Hyun Ju;Kim, Yeon Ju;Lim, Yeon-Jeong;Lee, Ingyeong;Park, Duck Hwan
    • 식물병연구
    • /
    • 제28권3호
    • /
    • pp.152-161
    • /
    • 2022
  • Several types of chemical bactericides have been used to control fire blight. However, their excessive usage leads to environmental deterioration. Therefore, several researchers have analyzed antagonistic microorganisms as promising, effective, and safe biological control agents (BCAs). The primary aim of this study was to screen for potential antagonistic bacteria that suppress Erwinia amylovora. Among the 45 isolates studied, 5 strains showed the largest inhibition zone against E. amylovora. 16S rRNA gene sequencing identified them as Bacillus amyloliquefaciens (KPB 15), B. stratosphericus (KPB 21), B. altitudinis (KPB 25), B. safensis (KPB 31), and B. subtilis (KPB 39). KPB 25 and 31 reduced the lesion size of fire blight by 50% in immature apple fruits, and did not show antagonism against each other. Therefore, KPB 25 and 31 were selected to develop an antagonistic mixture against fire blight. Although the mixture with KPB 25 and 31 showed a slightly increased ability to reduce lesion size on immature fruits, they did not exhibit a synergistic effect in reducing E. amylovora population compared to each strain alone. Nevertheless, we have identified these two strains as useful and novel BCAs against fire blight with additional benefits safety and potential in developing a mixture without loss of their activity, owing to the absence of antagonism against each other.

생태 위해성 예측 모형의 개발과 응용에 관한 연구

  • 이용주;변지연;권정환;이호주;김균;김용화
    • 한국환경독성학회:학술대회논문집
    • /
    • 한국환경독성학회 2003년도 춘계학술대회
    • /
    • pp.164-164
    • /
    • 2003
  • 전국 주요 산단 지역에서 현재 유통되고 있는 화학물질의 스크리닝 수준에서의 생태 위해성 평가를 수행하고, 체계적인 위해도 분석 시스템을 구축하기 위한 수생 및 육상 생태계가 통합된 생태 위해성 예측 모형을 개발하였다. 전국 118개 공단 중 시화반월, 전주, 대전, 대구, 청주, 울산, 구미, 여천공단 등 8개 주요 산단 지역을 program 개발을 위한 비교 대상 지역으로 선정하였고 이들 공단에서 사용되고 있는 약 1700여종의 화학물질의 물리 화학적 특성 자료와 생태 독성값의 문헌치, 추정치를 포함한 database를 구축하였다. 구축된 database를 활용하여 산단별, 화학물질별 생태 위해도를 상대적으로 비교한 결과 어류 만성의 위해도는 청주 공단>울산미포>여천 공단의 순이었고, 물벼룩 만성의 위해도는 시화반월>여천>울산미포 공단의 순이었다. 또한 산단별로 위해도 우선순위 물질을 선정하였으며 styrene, xylene 등의 위해도가 높게 나타났다. 이때 화학 물질의 수계 배출량은 TRI 자료와 사용량과의 상관관계로부터 구한 배출 계수를 적용하여 산정하였으며, 선정된 위해도 우선 순위 물질을 대상으로 실제 공단의 하천 시료를 채취, 분석하여 이 모형에 의해 예측된 생태 위해도의 타당성을 검증하고 보완하는 연구를 지속적으로 수행하여 예측 program의 신뢰도를 높이고자 한다.

  • PDF

Comparison of Dyes for Easy Detection of Extracellular Cellulases in Fungi

  • Yoon, Ji-Hwan;Park, Ji-Eun;Suh, Dong-Yeon;Hong, Seung-Beom;Ko, Seung-Ju;Kim, Seong-Hwan
    • Mycobiology
    • /
    • 제35권1호
    • /
    • pp.21-24
    • /
    • 2007
  • To evaluate which dye is effective in a plate assay for detecting extracellular cellulase activity produced by fungi, four chromogenic dyes including remazol brilliant blue, phenol red, congo red, and tryphan blue, were compared using chromagepic media. For the comparison, 19 fungal species belonging to three phyla, ascomycota, basidiomycota, and zygomycota were inoculated onto yeast nitrogen-based media containing different carbon substrates such as cellulose (carboxylmethyl and avicel types) and cellobiose labeled with each of the four dyes. Overall, the formation of clear zone on agar media resulting from the degradation of the substrates by the enzymes secreted from the test fungi was most apparent with media containing congo red. The detection frequency of cellulase activity was also most high on congo red-supplemented media. The results of this study showed that congo red is better dye than other three dyes in, a plate assay for, fungal enzyme detection.