An algorithm for adapting RED parameters to TCP traffic

Random early detection (RED) can stabilize the queue within a given target range and simultaneously achieve high throughput in the routers. However, the average queue length is quite sensitive to the network scenarios and it is difficult to adapt RED parameters to the changing network traffic. This paper develops an algorithm for systematically adapting RED parameters to variable network conditions such as link capacity, round- trip time and the number of TCP flows. Simulations demonstrate that this algorithm can stabilize the queue length within a target range and maintain high link utilization in a wide variety of network traffic conditions

The mechanism of adapting RED parameters to TCP traffic

Random Early Detection (RED) can stabilize the queue within a given target range and thus achieve high throughput in the routers. However, the average queue size is quite sensitive to network scenarios and it is difficult to adapt RED parameters to changing network traffic. In this paper we use a previously developed dynamic model of TCP behavior and linear feedback model of TCP/RED to analyze and design a mechanism for RED parameter tuning in response to changing network conditions like traffic load, link capacity and round-trip time. Even though the values of four key RED parameters are determined by varying network conditions, they can be tuned independently without consideration of the interactions among these RED parameters. Simulation results show that this mechanism can stabilize the queue and maintain high link utilization in a wide variety of network conditions

An average queue weight parameterization in a network supporting TCP flows with RED

In this paper we use a previously developed RED (random early detection) model to analyze and develop a quantitative approach of defining one of the RED parameters, average queue weight, while the network load level varies. First, we introduce the linear control system and the pre-developed RED model. Based on this model, we next develop a proposition aiming at the RED parameter, average queue weight, and the load level only, to ensure the system stay stable. Our research is intended to provide a quantitative basis for parameterizing RED while load level varies. We present ns simulations to support our analysis

An Algorithm for Adapting RED Parameters to TCP Traffic

Random early detection (RED) can stabilize the queue within a given target range and simultaneously achieve high throughput in the routers. However, the average queue length is quite sensitive to the network scenarios and it is difficult to adapt RED parameters to the changing network traffic. This paper develops an algorithm for systematically adapting RED parameters to variable network conditions such as link capacity, round- trip time and the number of TCP flows. Simulations demonstrate that this algorithm can stabilize the queue length within a target range and maintain high link utilization in a wide variety of network traffic conditions

Electrochemical Stimulation of PAH Biodegradation in Sediment

<div><p>Natural attenuation of PAH in sediments is usually slow due to prevailing anaerobic conditions in sediments. Electrochemical stimulation of PAH biodegradation is proposed and demonstrated for remediation of contaminated sediment. Two graphite electrodes were placed horizontally at different depths in PAH-spiked sediments; the cathode was near the water-sediment interface and the anode was laid in the deeper sediment. An external power of 2 V was continuously applied to the electrodes to stimulate PAH biodegradation. Redox potential around the anode in powered reactors increased gradually, and was 50–150 mV higher than that in the control. pH around the anode decreased to ∼6 from an initial value of 6.4 or 6.7 in powered reactors, which reflected water electrolysis. Phenanthrene concentration at the anode decreased with time, showing a unique Z-shaped profile in the sediment in powered reactors. PAH degrading genes around the anode in powered reactor were found to increase compared to the control reactor, which provided microbial evidence of biodegradation. These findings demonstrated the capability of this novel bioelectrochemical technology for the remediation of PAH-contaminated sediment.</p></div

An Average Queue Weight Parameterization in a Network Supporting TCP Flows with RED

In this paper we use a previously developed RED (random early detection) model to analyze and develop a quantitative approach of defining one of the RED parameters, average queue weight, while the network load level varies. First, we introduce the linear control system and the pre-developed RED model. Based on this model, we next develop a proposition aiming at the RED parameter, average queue weight, and the load level only, to ensure the system stay stable. Our research is intended to provide a quantitative basis for parameterizing RED while load level varies. We present ns simulations to support our analysis

Effect of Elemental Doping on the Adsorption Behavior and the Mechanism of Hydrogen Adsorption on the Zirconium Surface

This study used the Monte Carlo (MC) and density functional theory (DFT) methods to simulate the adsorption process of a H atom on element (vacancy, Cr, Sn, and Fe)-doped Zr(0001) surfaces and further analyzed the adsorption site distribution, adsorption energy, charge transfer, and electronic structure, etc. of the doped zirconium surface model. Simulated results indicated that (i) although the doping of vacancy, Cr, Sn, and Fe had a significant effect on the adsorption site distributions of the H atom on the Zr(0001) surface, they showed completely different distribution patterns. (ii) Vacancy doping promoted the adsorption of the H atom on the Zr(0001) surface. The H atom would penetrate the zirconium matrix along the vacancy and then occupy the octahedral gap stably. On the contrary, the doping of Cr, Sn, and Fe inhibited Zr(0001) surface hydrogen uptake in the order of Fe > Cr > Sn, where the effect of Sn could be negligible. (iii) Fe doping had the greatest effect on the chemical reaction mechanism of H adsorption on the Zr(0001) surface, which significantly converted the chemical reaction from Zr–H- to Fe–H-dominated, while Cr doping caused the formation of the Cr–H and Zr–H coaction mechanism, and Sn doping had almost no effect on the mechanism of H adsorption on the Zr(0001) surface

Additional file 1: of Sunlight-Induced Coloration of Silk

The file contains supplementary Figures S1–S6. (DOCX 1.63 MB

Growth curve and degradation curve of F4 and <i>E coli</i> Top10 (control) after different culture timed durations.

<p>Growth curve and degradation curve of F4 and <i>E coli</i> Top10 (control) after different culture timed durations.</p

Possible F4 quinclorac degradation products and pathways.

<p>Possible F4 quinclorac degradation products and pathways.</p