• Title/Summary/Keyword: Transport Mechanism

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Congestion Control to Improve QoS with TCP Traffic (TCP트래픽에 대한 QoS를 향상시키기 위한 폭주제어)

  • 양진영;이팔진;김종화
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.21-24
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    • 2000
  • End-to-end congestion control mechanism have been critical to the robustness and stability of the Internet. Most of today's Internet traffic is TCP, and we expect this to remain so in the future. TCP/IP is the intermediate transport layer candidate for today's applications. TCP uses an adaptive window-based flow control. The congestion avoidance and control algorithms deployed by TCP aims at using the available network bandwidth. This paper compares different congestion control policies, and proposes the new design mechanism for future public networks

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Numerical Investigations of Turbulent Piloted Non-Premixed Flames (난류 Pilot 비예혼합 화염장의 상세구조 해석)

  • Lee, Jeonwon;Jeon, Sangtae;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.185-186
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    • 2014
  • The multi-environment probability density function model has been applied to simulate the turbulent stratified premixed flames. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. The IEM mixing model is employed to represent the mixing process and the chemical mechanism is based on Gri 3.0 mechanism. Numerical results obtained in this study are precisely compared with experimental data in terms of unconditional and conditional means for scalar fields and velocity fields.

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Field Emission mechanism of undoped polycrystalline diamond films

  • Shim, Jae-Yeob;Song, Kie-Moon;Lee, Se-Jong;Baik, Hong-Koo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.135-136
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    • 2000
  • Field emission mechanism of undoped polycrystalline diamond films with a different amount of nondiamond carbon has been investigated using a transparent anode imaging technique and an electrolytic decoration technique. It is confirmed that for the films with a large amount of nondiamond carbon, electron transport occurs mainly through conductive grain boundaries while for the films with a small amount of nondiamond carbon, electron transports preferentially through diamond surface.

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PAN based-based copolymer membranes for dehydration of water/pyridine mixture (물/피리딘 혼합물 분리용 PAN계 공중합막)

  • 박춘호;남상용;이영무
    • Proceedings of the Membrane Society of Korea Conference
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    • 1998.10a
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    • pp.73-74
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    • 1998
  • 1. Introduction : We have researched to separate water effectively from aqueous pyridine solution. In our previous papers, we have proposed new separation mechanism, in-situ complex, which is different from solution-diffusion and accelerated transport by hydrogen bonding. We have adopted in-situ complex mechanism to membranes containing phosphoric acids as well as acrylic acid and sulfonic acid in copolymer for dehydration of pyridine.

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INTRODUCTION TO THE PHYSICS OF ACCRETION DISK

  • Wheeler, J. Craig
    • Publications of The Korean Astronomical Society
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    • v.8 no.1
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    • pp.163-168
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    • 1993
  • At intermediate mass transfer rates, accretion disks in binary star systems undergo a thermally-driven limit cycle instability. This instability leads to outburst episodes when the disk is bright and the flow through the disk is rapid separated by long intervals when the disk is dim and the flow through it is low. This intrinsic outburst mechanism can help to understand a wide range of astrophysical phenomena from dwarf novae to soft X -ray transients involving white dwarf, neutron star, and black holes. and to a deeper understanding of the mechanism of angular transport and viscosity in the accretion disk.

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BIOCHEMICAL MODEL AND MECHANISM FOR ACINETOBACTER NITRITE INHIBITION

  • Lee, Chan-Won;Weon, Seung-Yeon
    • Environmental Engineering Research
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    • v.10 no.1
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    • pp.22-30
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    • 2005
  • Nitrite accumulation is not unusual in batch processes such as sequencing batch reactor (SBR) with high-strength of ammonium or nitrate wastewaters. A possible mechanism of nitrite inhibition on Acinetobacter was depicted in a biochemical model, which the protonated species, nitrous acid form of nitrite, affects proton relating transport at the proton-pumping site crossing the cell membrane under unlimited carbon and phosphorus conditions. This effect exerts inhibition of phosphorylation under aerobic condition and yields low APT/ADP ratio, consequently decrease poly-P synthesis and phosphorus uptake from outside the cell in the model.

An Enhanced LPI Control Mechanism in Energy Efficient Ethernet (에너지 효율적인 이더넷에서 개선된 LPI 제어 메커니즘)

  • Lee, Sung-Keun;Jang, Yong-Jae;Yoo, Nam-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.5
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    • pp.983-989
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    • 2012
  • IEEE 802.3az LPI mechanism allows an Ethernet link to reduce power consumption by entering a low-power sleeping mode and letting some components being powered off when there is no data to be transmitted through the link. However, if small amount of packets are being sent periodically, such a mechanism can not obtain energy efficiency due to a high overhead caused by excessive mode transitions. In this paper, we propose an enhanced LPI mechanism which can perform state transition adaptively based on the traffic characteristics on transport layer and network status. This simulation result shows that proposed mechanism improves energy efficiency than LPI mechanism with respect to energy consumption rate for various traffic loads.

Numerical analysis of NOx formation characteristics in CH$_{4}$-air jet diffusion flame (CH$_{4}$-공기 분류 확산화염의 NOx 생성특성에 관한 수치해석)

  • O, Chang-Bo;Lee, Chang-Eon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.2
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    • pp.193-204
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    • 1998
  • Numerical analysis was performed with multicomponent transport properties and detailed reaction mechanisms for axisymmetric 2-D CH$_{4}$ jet diffusion flame. Calculations were carried out twice with the $C_{2}$-Thermal Mechanism including $C_{2}$ and thermal NO reactions and the $C_{2}$-Full Mechanism including prompt NO reactions in addition to the above $C_{2}$-Thermal NO mechanism. The results show that the flame structures such as flame temperature, major and minor species concentration are indifferent to respective mechanisms. The production path of Thermal NO is dominant comparing with that of Prompt NO in total NO production of pure CH$_{4}$ jet diffusion flame. This is because thermal NO mechanism mainly contributes to positive formation of NO in the whole flame region, but Prompt NO mechanism contributes to negative formation in the fuel rich region. In addition, 0$_{2}$ penetration near the nozzle outlet affects the flame structures, especially N0$_{2}$ formation characteristics.

Transepithelial Transport of Organic Cation and Its Inhibition by Sulfhydryl and Carboxyl Reagents in Opossum Kidney Cell Monolayer

  • Woo, Jae-Suk;Oh, Se-Ok;Jung, Jin-Sup;Kim, Yong-Keun;Lee, Sang-Ho
    • The Korean Journal of Physiology
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    • v.30 no.1
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    • pp.53-62
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    • 1996
  • Transepithelial transport of tetraethylammonium (TEA) was studied in monolayers of opossum kidney cells cultured on permeable membrane filters. $[^{14}C]-TEA$ was transported across the OK cell monolayer from basolateral to apical side by a saturable process which can be stimulated by acidification of the apical medium. The apparent Michaelis-Menten constant $(K_{m})$ and the maximum velocity$(V_{max})$ for the transport were $41\;{\mu}M$ and 147 pmole/ mg protein/ min, respectively. The transport was significantly inhibited by unlabelled TEA, amiloride, cimetidine, choline, and mepiperphenidol added to the basolateral side at 1 mM and was slightly inhibited by 5 mM $N_{1}-methylnicotinamide\;(NMN).$ Unlabelled TEA added to the apical side stimulated the $basolateral-to-apical\;{^{14}C}-TEA$ transport, suggesting that the TEA self-exchange mechanism was involved at the apical membrane. Sulfhydryl reagents such as ${\rho}-chloromercuribenzoic\;acid\;(PCMB)\;and \;{\rho}-chloro-mercuribenzene\;sulfonate \;(PCMBS)$ and carboxyl reagents such as N,N'-dicyclohexylcarbodiimidem (DCCD) and N-ethoxy-carbonyl-2-ethoxy-1,2-dihydro-quinoline(EEDQ) inhibited the TEA transport at both the basolateral and apical membranes of the OK cell monolayer. These results suggest that OK cell monolayers possess a vectorial transport system for organic cations which is similar to that for organic cation secretion in the renal proximal tubule.

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