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검색결과 429건 처리시간 0.031초

분산 이동객체 데이터베이스를 위한 k-NN질의 처리 (k-NN Query Process ing for Distributed Moving Object Dat abases)

  • 한종형;이준우;나연묵
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (C)
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    • pp.261-266
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    • 2006
  • GIS분야와 유비쿼터스 환경의 진보로 언제 어디서나 유무선으로 정보를 주고 받는 환경의 계선에 대한 발전이 계속 되어 왔다. 이런 환경에서 이동객체의 이용도가 증대됨에 따라 대용량의 객체 처리를 위해 분산 처리방식이 적용 되었다. 기존 연구의 k-NN질의는 단일 노드에서 질의 처리 비용의 절감에 중점을 두어 분할된 노드에서의 질의처리에 관련된 연구가 부족하였다. 분할된 노드에서 질의를 처리하기 위해서 고비용이 요구되는 k-NN질의를 위하여 본 논문에서는 Hybrid k-NN질의처리 방식을 제안한다. 제안방식은 k-NN질의와 범위질의 특성을 결합한 형태로 분할된 노드에 질의처리를 가능하게 하고, 질의처리 시 k-NN질의와 범위질의의 혼합으로 k-NN질의의 고비용을 절감하는 방법이다. 이 방법은 GALIS 프로토타입의 SLDS의 질의 처리 부분을 개선에 활용할 수 있다.

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WAPP ICC 데이터 웨어하우스 및 자료연계 시스템 설계 (The Design of Dat8 Warehouse and Data Link System for WAPP ICC)

  • 이강석;최승일;송재원;윤병주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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    • pp.279-281
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    • 2008
  • 현재 서부아프리카 지역의 경우, 대부분의 발전원은 수력과 화력에 의존하고 있으며 서부 아프리카경제공동체(ECOWAS) 15개 회원국의 전력수급률은 매우 낮은 수준일 뿐만 아니라 국가별 에너지 불균형 또한 심한 상태이다. 이에 서부 아프리카 전력공동체(WAPP)는 지역 간 에너지 불균형 해소 및 국가 간 전력망 연계를 위한 전력거래센터(ICC)의 구축을 추진하고 있다. 본 논문은 향후 WAPP ICC에서 본격적인 전력거래기능을 수행하기에 앞서 각 지역제어센터(CAC)의 전력 정보 수집, 분석 및 공유를 위한 자료연계 방안에 대해 서술하였으며 센터간의 자료연계를 위한 통신 프로토콜은 IEC 60870-6(ICCP) 프로토콜을 이용하였다.

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Rekeying Approach against Side Channel Attacks

  • Phuc, Tran Song Dat;Seok, Byoungjin;Lee, Changhoon
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2017년도 춘계학술발표대회
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    • pp.373-375
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    • 2017
  • Side-channel attacks and in particular differential power analysis (DPA) attacks pose a serious threat to cryptographic implementations. One approach to counteract such attacks is cryptographic schemes based on fresh re-keying. In settings of pre-shared secret keys, such schemes render DPA attacks infeasible by deriving session keys and by ensuring that the attacker cannot collect side-channel leakage on the session key during cryptographic operations with different inputs. This paper present a study on rekeying approach against side channel attacks with current secure schemes and their rekeying functions.

다중 SOGI-FLL 기반 엔진-발전기 시스템의 속도 추정 (Speed Estimation of Diesel-Generator Systems Based on Multiple SOGI-FLLs)

  • 다오녹닷;이동춘
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2017년도 추계학술대회
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    • pp.63-64
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    • 2017
  • This paper proposes a speed estimator for sensorless control of diesel-generator (genset) systems, where the speed of the genset is calculated from the back-EMF frequency of the generator. The back-EMF frequency is extracted from a phase output current by using multiple second-order generalized integrators (SOGIs) connected in parallel and series and separated frequency-locked loops. The proposed method (PS-SOGI-FLL) is able to estimate the fundamental frequency in the distorted output current with high accuracy and strong robustness. Simulation results are shown to verify the validity of the proposed method.

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NFAT(nuclear factor of activated T cells) 전사인자에 대한 천연물의 저해활성 (Inhibitory Effects of Natural Products against NFAT (nuclear factor of activated T cells) Transcription Factor)

  • 이임선;윈디엔닷;채흥복;심광해;김영호
    • 생약학회지
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    • 제34권2호통권133호
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    • pp.150-155
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    • 2003
  • The nuclear factor of activated T cells (NFAT) protein induce transcription of cytokine genes required for T-cell activation, including the IL-2 gene. Activation of NFAT normally plays a significant role in inducing immune response. However, excessive activation provokes immunopathological reactions including autoimmunity, transplant rejection and inflammation. Thus, several natural products were screened on the inhibitory activity against the NFAT transcription factor. Among them, Euonymus sieboldiana showed strong inhibitory activity against the NFAT transcription factor without affecting cell viability.

3D Building Detection and Reconstruction from Aerial Images Using Perceptual Organization and Fast Graph Search

  • Woo, Dong-Min;Nguyen, Quoc-Dat
    • Journal of Electrical Engineering and Technology
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    • 제3권3호
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    • pp.436-443
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    • 2008
  • This paper presents a new method for building detection and reconstruction from aerial images. In our approach, we extract useful building location information from the generated disparity map to segment the interested objects and consequently reduce unnecessary line segments extracted in the low level feature extraction step. Hypothesis selection is carried out by using an undirected graph, in which close cycles represent complete rooftops hypotheses. We test the proposed method with the synthetic images generated from Avenches dataset of Ascona aerial images. The experiment result shows that the extracted 3D line segments of the reconstructed buildings have an average error of 1.69m and our method can be efficiently used for the task of building detection and reconstruction from aerial images.

Solanoflavone, A New Biflavonol Glycoside from Solanum melongena: Seeking for Anti-Inflammatory Components

  • Shen Guanghai;Kiem Phan Van;Cai Xing-Fu;Li Gao;Dat Nguyen Tien;Choi Yeon A;Lee Young Mi;Park Yong Ki;Kim Young Ho
    • Archives of Pharmacal Research
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    • 제28권6호
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    • pp.657-659
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    • 2005
  • A new biflavonol glycoside named as solanoflavone (1) was isolated from aerial part of Solanum melongena. The chemical structure was elucidated as isorhamnetin-3-O-$\beta$-D-glucopyranoside-(4'$\to$O$\to$4"')-galangin-3"-O-$\to$-D-glucopyranoside on the basis of physicochemical and spectroscopic methods, including 2D NMR spectral techniques.

토끼에서 체내담즙이 아세부톨롤의 생체이용률 및 체내동태에 미치는 영향 (Effect of Bile juice on the Bioavailability and Pharmacokinetics of Acebutolol in Rabbits)

  • 최준식
    • 약학회지
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    • 제46권1호
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    • pp.47-51
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    • 2002
  • Although acebutolol (ABT) is almost completely absorbed in the gastrointestinal (Gl) tract, oral bioavailability of the drug is low due to extensive first-pass metabolism in the Gl tract and liver. In the present study, bioavailability and pharmacokinetics of ABT was studied in bile duct-bypassed rabbits after oral administration. For ABT the time to reach the plasma peak (T$_{max}$) and mean resident time (MRT) were increased by the treatment. For diacetolol (DAT), a metabolite of ABT area under the plasma concentration-time curve (AUC), T$_{max}$ and plasma half-life were increased by the treatment. These results indicate that oral bioavailability of ABT is associated with the enterohepatic recycling of bile juice components.nts.

Triterpenoids from Acanthopanax koreanum Root and Their Inhibitory Activities on NFAT Transcription

  • Cai, Xing-Fu;Lee, Im-Seon;Shen, Guanghai;Dat, Nguyen-Tien;Lee, Jung-Joon;Kim, Young-Ho
    • Archives of Pharmacal Research
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    • 제27권8호
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    • pp.825-828
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    • 2004
  • Two triterpenoids (1,4) and two triterpenoid glycosides (2,3) were isolated from the root of Acanthopanax koreanum (Araliaceae). Their structures were identified as impressic acid (1), acankoreoside A (2), 3-epi-betulinic acid 28-O-[(${\alpha}-L-rhamnopyranosyl(1{\rightarrow}4)-{\beta}-D-glucopyrano-syl(1{\rightarrow}6)]-{\beta}-D-glucopyranosyl]$ ester (3), and ursolic acid (4) by physicochemical and spectro-scopic methods. Of these compounds, impressic acid (1) exhibited a potent inhibitory activity against NFAT transcription factor ($IC_{50}:{\;}12.65{\;}{\mu\textrm{m}}$).

Gymnastone, A New Benzofuran Derivative from Gymnaster koraiensis

  • Dat, Nguyen-Tien;Kiem, Phan-Van;Cai, Xing-Fu;Shen, Quanghai;Bae, Ki-Hwan;Kim, Young-Ho
    • Archives of Pharmacal Research
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    • 제27권11호
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    • pp.1106-1108
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    • 2004
  • A new benzofuran derivative, named gymnastone [5-hydroxy-6-acetyl-2-(2-propane-1,2,3-triol)-benzofuran (1)], was isolated from the aerial part of Gymnaster koraiensis, together with viscidone (2) by repeated column chromatography. The structures of both compounds were identified by physico-chemical and spectral analysis including COSY, HMQC, and HMBC experiments.