• 제목/요약/키워드: Dos

검색결과 428건 처리시간 0.021초

전자경매를 위한 보안 프로토콜 (A Secure Protocol for the Electronic Auction)

  • 원보스;장인주;유형선
    • 한국전자거래학회지
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    • 제12권4호
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    • pp.29-36
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    • 2007
  • Collins[1]등이 제안한 멀티 에이전트 테스트 베드는 발행/가입 시스템, 타임 릴리즈 암호 법, 그리고 익명 통신 기법에 기반을 두고 있다. 최근 Jaiswal[2]등은 Collins의 멀티 에이전트 테스트 베드를 향상시키는 프로토콜을 제안하였다. 그러나 Jaiswal의 프로토콜 또한 데이터 재전송 공격, DOS 공격, 익명성 폭로 등과 사용자와 공급자 사이의 충돌 등의 문제에 대하여 취약함을 보인다. 본 논문에서는 DOS 공격의 가능성을 줄이고, 공급자에게 티켓 토큰과 처리 순번 제공함으로써 데이터 재전송 공격을 피할 수 있는 프로토콜을 제안한다. 또한 본 논문의 제안 프로토콜에서, 마켓은 공급자에게 난수 생성 방법과 결정과정의 데이터를 공유하기 위한 보간 다항식을 제공하여 사용자와 특정한 공급자 사이의 충돌을 피할 수 있게 한다.

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Characterization of Density-of-States in Polymer-based Organic Thin Film Transistors and Implementation into TCAD Simulator

  • Kim, Jaehyeong;Jang, Jaeman;Bae, Minkyung;Lee, Jaewook;Kim, Woojoon;Hur, Inseok;Jeong, Hyun Kwang;Kim, Dong Myong;Kim, Dae Hwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제13권1호
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    • pp.43-47
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    • 2013
  • In this work, we report extraction of the density-of-states (DOS) in polymer-based organic thin film transistors through the multi-frequency C-V spectroscopy. Extracted DOS is implemented into a TCAD simulator and obtained a consistent output curves with non-linear characteristics considering the contact resistance effect. We employed a Schottky contact model for the source and drain to fully reproduce a strong nonlinearity with proper physical mechanisms in the output characteristics even under a very small drain biases. For experimental verification of the model and extracted DOS, 2 different OTFTs (P3HT and PQT-12) are employed. By controlling the Schottky contact model parameters in the TCAD simulator, we accurately reproduced the nonlinearity in the output characteristics of OTFT.

Aggressive unicystic ameloblastoma affecting the posterior mandible: late diagnosis during orthodontic treatment

  • Lopes, Sergio Lucio Pereira de Castro;Flores, Isadora Luana;Gamba, Thiago de Oliveira;Ferreira-Santos, Rivea Ines;Moraes, Mari Eli Leonelli de;Cabello, Aline Alvarez;Moutinho, Paula Nascimento
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제43권2호
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    • pp.115-119
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    • 2017
  • Maxillofacial images must be examined to find pathologies not identified during clinical examination. Unicystic ameloblastoma (UA) extending to the mandibular body and ramus was neglected on initial panoramic radiographic examination. After orthodontic therapy, a huge lesion was observed clinically and through imaging exams. After the conservative surgery, no recurrence was observed during five years of follow-up. This case emphasized the need for careful evaluation of patient images focusing on the oral diagnosis before any dental treatment planning, including orthodontic therapy.

304L 스테인리스강의 열처리에 따른 입계부식민감도 연구 (Sensitivity to Intergranular Corrosion According to Heat Treatment of 304L Stainless Steel)

  • 장형민;김동진;김홍표
    • Corrosion Science and Technology
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    • 제19권1호
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    • pp.37-42
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    • 2020
  • Even though 304 low-carbon (304L) stainless steel was developed to enhance the resistance to intergranular corrosion and stress corrosion cracking, it is occasionally subject to degradation in harsh environments. The degree of sensitization (DOS) of 304L stainless steel was studied as a function of sensitization using a double-loop electrochemical potentiokinetic reactivation (DL-EPR) method. Sensitizing heat treatment was performed in an Ar atmosphere at 500℃, 600℃, and 700℃, with heat treatment times varying from 0 to 96 h. DOS was measured by the ratio of the peak current density value of the forward scan to that of the reverse scan. After the EPR experiment, the specimen surface was observed by scanning electron microscopy and energy dispersive spectroscopy. The DOS of the specimens heat-treated at 600℃ increased with heat treatment times up to 48 h and then decreased due to a self healing effect. The DOS was higher in specimens heat-treated at 600℃ than those at 500℃ or 700℃. Corrosion of the sensitized specimens occurred mainly at the δ-γ phase boundary. The corrosion morphology at the δ-γ phase boundary changed with sensitizing heat-treatment conditions due to differences in chromium activity in γ austenite and δ ferrite.

전선피복용 컴파운드의 제조에서 가소제의 종류와 첨가량에 따른 물성 변화 연구 (Study on Property Modification with Kind and Additive Amount of Plasticizer in the Manufacture of Compounds for Cable Sheath)

  • 리시앙수;이상봉;조을룡
    • 반도체디스플레이기술학회지
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    • 제18권2호
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    • pp.11-16
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    • 2019
  • The four different polymer compounds were manufactured with the two kinds of plasticizers [(di-2-ethylhexyl sebacate(DOS), and di-2-butyl sebacate(DBS)] and two different additive amounts(18, 26 phr) of the same plasticizer for making cable sheath for ship. Ethylene-vinylacetate, ethylene-propylene-diene-copolymer as matrix polymers and ethylene-vinylacetate grafted maleic anhydride as coupling agent were selected for compounding with fire retardant, closslinking agent, filler, and other additives besides plasticizer. The compound including DOS showed the higher ${\Delta}T$ than that including DBS at the same additive amount in the rheology test. And with increasing plasticizer, the compounds resulted in lower tensile strength and higher elongation by lubricating effect of plasticizer. DOS yielded better aging resistance and cold resistance than DBS due to the good heat resistance and low solidifying point of DOS compared to DBS.

다짐된 궤도 흙노반 재료의 전단탄성계수(G)-전단변형률(γ)-포화도(S) 관계특성 분석 (Analysis of Shear Modulus(G)-Shear Strain(γ)-Degree of Saturation(S) Characteristics of Compacted Subgrade Soil used as Railway Trackbed)

  • 최찬용;이성혁;임유진;김대성;박재범
    • 한국철도학회논문집
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    • 제18권2호
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    • pp.127-138
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    • 2015
  • 본 연구에서는 국내 철도 궤도하부 다져진 흙노반의 강성 평가를 위하여 Stokoe 방식의 고정단-자유단 중형 공진주 시험기(D=10cm, L=20cm)를 이용, 구속압 및 전단변형률 증가시 포화도(S)변화에 따른 전단탄성계수의 분포변화를 조사, 분석하였다. 분석결과 포화도가 증가할수록 최대전단탄성계수는 감소하고 정규화 전단탄성계수는 증가하는 경향을 보였다. 분석결과를 바탕으로 포화도(S)~전단탄성계수(S)~전단변형률(${\gamma}$) 사이의 고유한 감소 관계특성을 관찰할 수 있었다. 이러한 특성수립 가능성을 기반으로 향후 광범위한 추가시험을 통하여 예측모델을 수립하고 소정의 모델계수 값들을 획득할 수 있을 것이다.

440A 강의 입계부식에 미치는 합금원소와 열처리의 영향(II) (The Effect of Alloying Elements and Heat Treatment on the Intergranular Corrosion of 440A Martensitic Stainless Steel(II))

  • 김영철;정병호;강창룡
    • 동력기계공학회지
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    • 제15권3호
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    • pp.52-57
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    • 2011
  • 440A martensitic stainless steels which were modified with reduced carbon content(~0.5wt.%) and addition of small amount of vanadium, tungsten and molybdenum 0.4wt.%, 0.4wt.% and 0.68wt.% respectively were manufactured. Effects of alloying elements and tempering temperatures on the intergranular corrosion were investigated through the method of DL-EPR(Double-electrochemical potentiodynamic reactivation). It was thought that the highest DOS(Degree of sensitization) of specimens was obtained at the tempering temperature of $450^{\circ}C$ regardless of types of alloy because of the precipitation of Cr7C3. Addition of vanadium lowered DOS a little above the tempering temperature of $550^{\circ}C$. It was considered to be effected by precipitation of VC carbides. Intergranular corrosion was influenced more by tempering temperature than by alloying elements of V, W and Mo.

Identification of 2-Deoxy-scyllo-inosose Synthase in Aminoglycoside Producer Streptomyces

  • Kharel, Madan-Kumar;Subba, Bimala;Lee, Hei-Chan;Liou, Kwang-Kyoung;Woo, Jin-Suk;Kim, Dong-Hwan;Moon, Young-Ho;Sohng, Jae-Kyung
    • Journal of Microbiology and Biotechnology
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    • 제13권5호
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    • pp.828-831
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    • 2003
  • Although most of the DOS containing aminoglycosides are produced by Streptomyces, very little information is available about their biosynthesis. In the present paper, we report a method to isolate DOI synthase, a key enzyme in the biosynthesis of DOS, from aminoglycoside producer Streptomyces. PCR primers based on conserved region of DOI synthases were specific and reliable for the isolation of the biosynthetic genes of DOS containing aminoglycosides or the screening of the aminoglycoside producers. The use of DOI synthase as a probe could save both time and cost of cloning aminoglycoside biosynthetic genes.

도스 단말기의 무선 원격제어 시스템 설계 (Wireless Remote Control System for DOS Client)

  • 김창훈;변정식;한병준;민병기;김승준
    • 한국멀티미디어학회:학술대회논문집
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    • 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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    • pp.93-96
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    • 2012
  • 본 논문에서는 유선기반 DOS(Disk Operating System) 제어의 다양한 단점들을 극복하기 위해 무선기반의 도스 원격제어 시스템을 제안한다. 제안한 시스템은 비디오 전송기, 가상 네트워크 드라이버, 무선 키보드 모듈로 구성되며 도스와 윈도우즈 컴퓨터간의 중계기 역할을 수행한다. 무선 랜 환경(802.11n)에서 성능을 측정한 결과 약 15Mbps 통신환경에서 영상의 경우 초당 10 ~ 15 프레임을 전송하고, 네트워크 드라이버의 연결속도는 약 8Mbps이며, 키보드 입력의 경우 실시간 처리가 가능하다. 따라서 본 논문에서 제안한 시스템은 DOS기반 어플리케이션의 원격제어 솔루션으로 매우 적합하다 할 수 있다.

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Ab initio calculation of half-metallic ferrocene-based nanowire

  • Kim, Seongmin;Park, Changhwi
    • EDISON SW 활용 경진대회 논문집
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    • 제3회(2014년)
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    • pp.425-429
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    • 2014
  • Half-metallic nanostructure is highly applicable in the field of Spintronics and electronic device technology. We examine the electronic properties of a ferrocene-based nanowire as a possible candidate for a half-metallic nanostructure using VASP and SIESTA. Ferrocene-based nanowire shows high stability in both binding energy simulation and molecular dynamics (MD) simulation. The density of states (DOS) and the projected DOS of the ferrocene-based nanowire indicate that one-dimensional clustering of ferrocene molecules can be explained because of p-d orbital hybridization between iron and carbon. Half-metallic property and energy dispersion at the Fermi level due to one-dimensional structure is also observed from the DOS results.

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