• 제목/요약/키워드: Dos

검색결과 426건 처리시간 0.028초

덕트형 세정집진기의 입자포집 특성실험 (An Experiment on Particle Collection Characteristics of a Duct-type Wet Scrubber)

  • 유경훈;여국현;손승우;황광호;정진원;김윤신
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1795-1800
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    • 2004
  • DOS and NaCl aerosol particles with geometric mean diameter of $0.1{\sim}3.0{\mu}m$ geometric standard deviation of $1.1{\sim}1.8$ and total number concentration of $450{\sim}400$ $particles/cm^3$ were used to determine collection efficiencies of a duct-type wet scrubber with respect to particle size. The tested operating variables included air velocity and water injection rate. It was shown from the experimental results that the collection efficiencies increased with increasing water injection rate and decreasing air velocity. It was also seen that the collection efficiency of the Duct-type wet scrubber is mainly governed by the mechanism of inertial impaction.

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Effects of Cumulus Cells and Follicular Fluid on Plasminogen Activator Activity during In Vitro Maturation of Porcine Oocytes

  • Ann Ji-Young;Sa Soo-Jin;Cao Yang;Lee Sang-Young;Cheon Hee-Tae;Yang Boo-Keun;Park Choon-Keun
    • Reproductive and Developmental Biology
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    • 제30권2호
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    • pp.135-141
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    • 2006
  • The present study was conducted to investigate the effects of cumulus cells and porcine follicular fluid (pFF) on plasminogen activator (PA) activity and oocytes maturation in vitro in the pig. The cumulus-oocyte complexes (COCs) and denuded oocytes (DOs) were incubated in NCSU-23 medium with or without 10% pFF for 0, 24, or 48 hr. In the presence of cumulus cells, the proportions of oocytes matured to metaphase-II stage were significantly (P<0.05) higher in medium with pFF than without pFF (69.8 vs. 37.7%, respectively). When COCs and DOs were cultured in the presence of pFF, tissue-type PA (tPA), urokinase-type PA (uPA), and tPA-PA inhibitor (tPA-PAI) were observed in COCs, and PA activities were higher at 48 hr than 24 hr. When COCs and DOs were cultured in the absence of pFF, tPA and tPA-PAI were observed in COCs, and PA activities were increased as duration of culture increased. No PA activities were detected in DOs regardless of pFF supplementation. When porcine oocytes were cultured in the presence of pFF for 24 and 48 hrs, the activities of tPA-PAI, tPA, and uPA were observed in both COCs and DOs. In medium of absence of pFF, PA activities were observed in oocytes with cumulus cells only. On the other hand, three plasminogen-dependent lytic bands (tPA-PAI, tPA, and uPA) were observed in pFF cultures. Particularly uPA activity was higher than the other kinds of PA activity. When oocytes and cumulus cells were separated from porcine COCs at 0 hr of culture, tPA-PAI, tPA, and uPA were detected in cumulus cells at 48 hr of culture, but no PA activities were in DOs. The presence of pFF and cumulus cells in maturation medium stimulated not only nuclear and cytoplasmic maturation in porcine COCs, but also PA production by cumulus cells and COCs. It is possible that PAs produced by cumulus cells migrated through the gap junction between oocyte and cumulus cells. These results suggest that porcine oocytes have no ability to produce PA themselves.

네트워크 기반 프로토콜 공격에 대한 침입탐지 시스템의 설계 (Design of Network-based Intrusion Detection System for Protocol Attack)

  • 최준욱;이정준;정운영;정선화;박석천
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (A)
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    • pp.523-525
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    • 2002
  • DOS (Denial Of Service)에 대한 공격은 시스템의 정상적인 동작을 방해하여 시스템 사용자에 대한 서비스 제공을 거부하도록 만드는 공격으로 현재 이의 공격에 대한 탐지 알고리즘 및 연구들이 많이 제시되고 있다. 본 논문에서는 네트워크 또는 트랜스포트 계층에 해당하는 프로토콜(TCP/IP, ICMP, UDP) 공격을 분석하고 이들 프로토콜의 취약점을 공격하는 DOS 공격 이외의 다른 공격을 탐지하기 위하여 프로토콜의 기능별, 계층별에 따른 모듈화 작업을 통하여 네트워크 침입탐지 시스템을 설계하였다.

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교육용 한글 C 프로그래밍 언어 사전처리기의 설계 및 구현 (Design and Implementation of Preprocessor for Educational Hangul C Programming Language)

  • 김창희;이상락;홍성수;심재홍
    • 한국통신학회논문지
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    • 제18권2호
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    • pp.239-249
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    • 1993
  • 본 논문은 터보 C언어에 대응하는 한글 C언어를 설계, 구현하였다. 한글C언어 명령어는 초 중 고등학생들이 이해하기 쉬운 용어로 선정하였으며 도스(DOS) 명령어와 오류 메시지도 한글화하였다.

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The Analytical Solutions for Finite Clusters of Cubic Lattices

  • Gean-Ha Ryu;Hojing Kim
    • Bulletin of the Korean Chemical Society
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    • 제12권5호
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    • pp.544-554
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    • 1991
  • Using the Huckel method, we obtain the analytical expressions for eigenvalues and eigenvectors of s.c., f.c.c. and b.c.c. clusters of rectangular parallelepiped shape, and of an arbitrary size. Our formula converage to those derived from the Bloch sum, in the limit of infinite extension. DOS and LDOS reveal that the major contribution of the states near Fermi level originates from the surface atoms, also symmetry of DOS curves disappears by the introduction of 2nd nearest neighbor interactions, in all the cubic lattices. An accumulation of the negative charges on surface of cluster is observed.

2단 정전식 세정집진기의 집진 및 가스제거 특성 (An Experiment on Particle Collection and Gas Removal in a 2-Stage Electrostatic Wet Scrubber)

  • 여국현;유경훈;손승우;김윤신
    • 설비공학논문집
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    • 제18권9호
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    • pp.745-752
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    • 2006
  • DOS and NaCl aerosol particles were used to determine collection efficiencies of a 2-stage electrostatic wet scrubber with respect to particle size. The DOS and NaCl aerosols have geometric mean diameters of 0.1-3.0 urn, geometric standard deviations of $1.1{\sim}1.8$ and total number concentrations of $450{\sim}2,400\;particles/cm^3$. The tested operating variables for the electrostatic wet scrubber included air velocity and water injection rate. It was shown from the experimental results that particle collection efficiencies increased in the submicron particle size range when different polarities were applied on the water nozzle and corona wire, respectively. This increase in the collection efficiency is attributed to strong electrostatic attraction between the negative water droplets and positive submicron particles. The collection efficiencies also increased when water injection rate was increased or air velocity was decreased. Meanwhile, the pressure drop across the wet scrubber decreased by 90% compared with the existing mechanical wet scrubber. Finally, ammonia gas was used to determine gas removal efficiencies. It was observed that the gas removal efficiencies increased when the air velocity was decreased or the water injection rate was increased.

Effect of mechanically deboned poultry meat content on technological properties and sensory characteristics of lamb and mutton sausages

  • Massingue, Armando Abel;Filho, Robledo de Almeida Torres;Fontes, Paulo Rogerio;Ramos, Alcineia de Lemos Souza;Fontes, Edimar Aparecida Filomeno;Perez, Juan Ramon Olalquiaga;Ramos, Eduardo Mendes
    • Asian-Australasian Journal of Animal Sciences
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    • 제31권4호
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    • pp.576-584
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    • 2018
  • Objective: This study aimed to develop a value-added product concerning technological and sensory characteristics changes of the use of mechanically deboned poultry meat (MDPM) as meat replacer in lamb and mutton emulsion-type sausages (mortadella). Methods: Sausages were produced with lamb and mutton and with different contents of MDPM. Six treatments, using lamb or mutton and 0%, 30%, and 60% of MDPM in relation to the meat batter, were produced and analyzed for pH, proximal composition, calcium and residual nitrite content, water activity, 2-thiobarbituric acid reactive substances (TBARS), instrumental color and texture profile. The sensory profile of the mortadella's was also evaluated by acceptance test and check-all-that-applies (CATA) analysis. Results: The MDPM addition increased (p<0.05) fat, residual nitrite and calcium content in the all sausage formulations, but mutton sausage had (p<0.05) higher fat and lower moisture content than lamb sausage. The pH, water activity, TBARS index and color was not affected by MDPM additions, while the mutton sausages were significantly redder (higher $a^*$, $C^*$, and lower $h^{\circ}$) and darker (lower $L^*$) than lamb sausages. Adding up to 60% of MDPM reduced (p<0.05) sausages hardness and chewiness. Overall, the meat replacement by MDPM increased the sausages acceptance, but the mutton sausage with 30% of MDPM replacer were the most preferred. Consumers related that pink color, glossy appearance, poultry meat-like taste, soft texture, juicy and greasy mouth feel to all sausages contain MDPM according to CATA analysis. Conclusion: Mutton from culled ewes can be utilized for mortadella production with 30% replacement of lean mutton and fat by MDPM.