To reduce the TCP flow processing cost, some bit patterns selected from the TCP/IP packet can be used as TCP flow identification. Based on the entropy and randomness analysis of the distribution of sequence number （S...To reduce the TCP flow processing cost, some bit patterns selected from the TCP/IP packet can be used as TCP flow identification. Based on the entropy and randomness analysis of the distribution of sequence number （SN） and acknowledgement number （AN） in the first packet of a TCP flow, this paper proposes a new uniform TCP flow identification by sequence and acknowledgement number （FIDSAN） to the heavy-tailed IP or TCP traffic. The experimental results suggest that some bits in the TCP sequence number and acknowledgment number can be selected out as flow ID with acceptable confliction probability. The bit length of flow ID selected under given confliction probability can be conducted from an equation deduced from the observing window and flow ID range. FIDSAN has low computation cost in the comparison with the traditional methods, such as 5-tuple, CRC, and Checksum etc.展开更多
A 2-D laminar flow model was established for CFD analysis of air-flow between louvered fins. Two louvered fins are studied based on commercial software FLUENT. Air-flow pressure drop characteristics are derived on the...A 2-D laminar flow model was established for CFD analysis of air-flow between louvered fins. Two louvered fins are studied based on commercial software FLUENT. Air-flow pressure drop characteristics are derived on the calculation of Reynolds number from 75.3 to 600. The numerical results are in good agreement with the experimental data when Reynolds is lower.展开更多
In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in th...In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die.Two different multi-hole porthole dies with and without pockets in lower die were designed.And the extrusion process was simulated based on the commercial software DEFORM-3D.The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs.In addition,the maximum temperature at the die bearing and the peak extrusion load decrease,which indicates the possibility of increasing the extrusion speed and productivity.展开更多
Canopy air curtain （CAC） technology has been developed by the National Institute for Occupational Safety and Health （NIOSH） for use on continuous miners and subsequently roof bolting machines in underground coal m...Canopy air curtain （CAC） technology has been developed by the National Institute for Occupational Safety and Health （NIOSH） for use on continuous miners and subsequently roof bolting machines in underground coal mines to protect operators of these machines from overexposure to respirable coal mine dust. The next logical progression is to develop a CAC for shuttle cars to protect operators from the same overexposures. NIOSH awarded a contract to Marshall University and J.H. Fletcher to develop the shuttle car CAC. NIOSH conducted laboratory testing to determine the dust control efficiency of the shuttle car CAC. Testing was conducted on two different cab configurations： a center drive similar to that on a Joy 10SC32AA cab model and an end drive similar to that on a Joy 10SC32AB cab model. Three different ventilation velocities were tested-0.61, 2.0, 4.3 rrds （120, 400, and 850 fpm）. The lowest, 0.61 m/s （120 fpm）, represented the ventilation velocity encountered during loading by the continuous miner, while the 4.3 m/s （850 fpm） velocity represented ventilation velocity airflow over the shuttle car while tramming against ventilation airflow. Test results showed an average of the dust control efficiencies ranging from 74 to 83% for 0.61 m/s （120 fpm）, 39%-43% for 2.0 m/s （400 fpm）, and 6%-16% for 4.3 m/s （850 fpm）. Incorporating an airflow spoiler to the shuttle car CAC design and placing the CAC so that it is located 22.86 cm （9 in.） forward of the operator improved the dust control efficiency to 51%-55% for 4.3 m/s （850 fpm） with minimal impact on dust control efficiencies for lower ventilation velocities. These laboratory tests demonstrate that the newly developed shuttle car CAC has the potential to successfully protect shuttle car operators from coal mine respirable dust overexposures.展开更多
The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), a...The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), alternative moving window factor analysis (AMWFA) algorithms and normalization method based on the peak areas; the flavones in the barks and leaves of Eucommia ulmoides Oliver were separated on an ODS column by gradient elution carried out with the flow phase consisting of water, methanol and phosphoric acid (0.1%), and their contents were quantitatively determined by standard curve method and diode array detection (DAD) at 362 nm. The results show that 68 and 73 compounds respectively from essential oils of the barks and leaves of Eucommia ulmoides Oliver are identified, and there are 33 mutual compounds among 108 compounds determined. The total contents of these volatile components of the two samples possess 92.9% and 97.75% of the gross of the relevant essential oils, respectively; the contents of the rutin, quercetin and kaempferol in the barks and leaves of Eucommia ulmoides Oliver are 0.016 9, 0.003 6, 0.002 1 and 0.064 4, 0.030 2, 0.010 0 mg/g, respectively, and the determination recoveries are 95.2%-106.2%. The comparative analysis shows that for the barks and leaves of Eucommia ulmoides Oliver, there are significant differences in their components of the relevant essential oils and flavones.展开更多
Normal skylights bring light into the spaces located below them. By the use of IR （infrared radiation） transmissive polymer films and IR-emitting and absorbing gases, an advanced version of the skylight may supply p...Normal skylights bring light into the spaces located below them. By the use of IR （infrared radiation） transmissive polymer films and IR-emitting and absorbing gases, an advanced version of the skylight may supply passive cooling and thermal insulation to the room located below it. This novel radiative skylight can, in its cooling mode, lead heat from the room below, to the cool skies located above the skylight. When cooling is no longer needed or attainable, the skylight will in its cooling mode provide the room with an optimal amount of thermal resistance. This article is a progress reporting on the modeling of the skylight. The main work is done to combine the different heat transfer methods into one single model by the use of the commercial program Comsol 4.1. The results show that a cooling effect of 100 W/ma is achievable when the skylight is compared with a similar skylight containing only air.展开更多
Previous weighted frequent pattern （WFP） mining algorithms are not suitable for data streams for they need multiple database scans. In this paper, we present an efficient algorithm SWFP-Miner to mine weighted freque...Previous weighted frequent pattern （WFP） mining algorithms are not suitable for data streams for they need multiple database scans. In this paper, we present an efficient algorithm SWFP-Miner to mine weighted frequent pattern over data streams. SWFP-Miner is based on sliding window and can discover important frequent pattern from the recent data. A new refined weight definition is proposed to keep the downward closure property, and two pruning strategies are presented to prune the weighted infrequent pattern. Experimental studies are performed to evaluate the effectiveness and efficiency of SWFP-Miner.展开更多
Abstract： The most popularly used fin types in compact heat exchangers are the serrated fins, wavy fins, louvered fins and plain fins. Amongst these fin types the serrated fins assume lot of importance due to its enh...Abstract： The most popularly used fin types in compact heat exchangers are the serrated fins, wavy fins, louvered fins and plain fins. Amongst these fin types the serrated fins assume lot of importance due to its enhanced thermo-hydraulic performance. Thermo-hydraulic design of CHEs （Compact heat exchangers） is strongly dependent upon the predicted/measured dimensionless performance （Colburnj factor and Fanning friction vs. Reynolds number） of heat transfer surfaces. This paper describes the numerical analysis to study the heat transfer coefficient and friction factor of Serrated fins in water medium. CFD （Computational fluid dynamics） methodology has been used to develop the single phase water heat transfer coefficient and friction factor correlations for serrated fins using ANSYS Fluent 14.5. The results are compared with previous air-cooled models and experimental results of water. The water cooled CFD analysis results shows that the Prandtl number has a large effect on the Nusselt number of the serrated fin geometry. Finally, the generalized correlations are developed for serrated fins taking all geometrical parameters into account. This numerical estimation can reduce the number of tests/experiments to a minimum for similar applications.展开更多
文摘To reduce the TCP flow processing cost, some bit patterns selected from the TCP/IP packet can be used as TCP flow identification. Based on the entropy and randomness analysis of the distribution of sequence number （SN） and acknowledgement number （AN） in the first packet of a TCP flow, this paper proposes a new uniform TCP flow identification by sequence and acknowledgement number （FIDSAN） to the heavy-tailed IP or TCP traffic. The experimental results suggest that some bits in the TCP sequence number and acknowledgment number can be selected out as flow ID with acceptable confliction probability. The bit length of flow ID selected under given confliction probability can be conducted from an equation deduced from the observing window and flow ID range. FIDSAN has low computation cost in the comparison with the traditional methods, such as 5-tuple, CRC, and Checksum etc.
文摘A 2-D laminar flow model was established for CFD analysis of air-flow between louvered fins. Two louvered fins are studied based on commercial software FLUENT. Air-flow pressure drop characteristics are derived on the calculation of Reynolds number from 75.3 to 600. The numerical results are in good agreement with the experimental data when Reynolds is lower.
基金Project(2007BAE38B00) supported by the National Key Technology R&D Program in the 11th Five Year Plan of China
文摘In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die.Two different multi-hole porthole dies with and without pockets in lower die were designed.And the extrusion process was simulated based on the commercial software DEFORM-3D.The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs.In addition,the maximum temperature at the die bearing and the peak extrusion load decrease,which indicates the possibility of increasing the extrusion speed and productivity.
文摘Canopy air curtain （CAC） technology has been developed by the National Institute for Occupational Safety and Health （NIOSH） for use on continuous miners and subsequently roof bolting machines in underground coal mines to protect operators of these machines from overexposure to respirable coal mine dust. The next logical progression is to develop a CAC for shuttle cars to protect operators from the same overexposures. NIOSH awarded a contract to Marshall University and J.H. Fletcher to develop the shuttle car CAC. NIOSH conducted laboratory testing to determine the dust control efficiency of the shuttle car CAC. Testing was conducted on two different cab configurations： a center drive similar to that on a Joy 10SC32AA cab model and an end drive similar to that on a Joy 10SC32AB cab model. Three different ventilation velocities were tested-0.61, 2.0, 4.3 rrds （120, 400, and 850 fpm）. The lowest, 0.61 m/s （120 fpm）, represented the ventilation velocity encountered during loading by the continuous miner, while the 4.3 m/s （850 fpm） velocity represented ventilation velocity airflow over the shuttle car while tramming against ventilation airflow. Test results showed an average of the dust control efficiencies ranging from 74 to 83% for 0.61 m/s （120 fpm）, 39%-43% for 2.0 m/s （400 fpm）, and 6%-16% for 4.3 m/s （850 fpm）. Incorporating an airflow spoiler to the shuttle car CAC design and placing the CAC so that it is located 22.86 cm （9 in.） forward of the operator improved the dust control efficiency to 51%-55% for 4.3 m/s （850 fpm） with minimal impact on dust control efficiencies for lower ventilation velocities. These laboratory tests demonstrate that the newly developed shuttle car CAC has the potential to successfully protect shuttle car operators from coal mine respirable dust overexposures.
基金Project(20235020) supported by the National Natural Science Foundation of China
文摘The chemical components of the essential oils in the barks and leaves of Eucommia ulmoides Oliver were analyzed and compared by chromatograms and mass spectra technique, heuristic evolving latent projections (HELP), alternative moving window factor analysis (AMWFA) algorithms and normalization method based on the peak areas; the flavones in the barks and leaves of Eucommia ulmoides Oliver were separated on an ODS column by gradient elution carried out with the flow phase consisting of water, methanol and phosphoric acid (0.1%), and their contents were quantitatively determined by standard curve method and diode array detection (DAD) at 362 nm. The results show that 68 and 73 compounds respectively from essential oils of the barks and leaves of Eucommia ulmoides Oliver are identified, and there are 33 mutual compounds among 108 compounds determined. The total contents of these volatile components of the two samples possess 92.9% and 97.75% of the gross of the relevant essential oils, respectively; the contents of the rutin, quercetin and kaempferol in the barks and leaves of Eucommia ulmoides Oliver are 0.016 9, 0.003 6, 0.002 1 and 0.064 4, 0.030 2, 0.010 0 mg/g, respectively, and the determination recoveries are 95.2%-106.2%. The comparative analysis shows that for the barks and leaves of Eucommia ulmoides Oliver, there are significant differences in their components of the relevant essential oils and flavones.
文摘Normal skylights bring light into the spaces located below them. By the use of IR （infrared radiation） transmissive polymer films and IR-emitting and absorbing gases, an advanced version of the skylight may supply passive cooling and thermal insulation to the room located below it. This novel radiative skylight can, in its cooling mode, lead heat from the room below, to the cool skies located above the skylight. When cooling is no longer needed or attainable, the skylight will in its cooling mode provide the room with an optimal amount of thermal resistance. This article is a progress reporting on the modeling of the skylight. The main work is done to combine the different heat transfer methods into one single model by the use of the commercial program Comsol 4.1. The results show that a cooling effect of 100 W/ma is achievable when the skylight is compared with a similar skylight containing only air.
文摘Previous weighted frequent pattern （WFP） mining algorithms are not suitable for data streams for they need multiple database scans. In this paper, we present an efficient algorithm SWFP-Miner to mine weighted frequent pattern over data streams. SWFP-Miner is based on sliding window and can discover important frequent pattern from the recent data. A new refined weight definition is proposed to keep the downward closure property, and two pruning strategies are presented to prune the weighted infrequent pattern. Experimental studies are performed to evaluate the effectiveness and efficiency of SWFP-Miner.
文摘Abstract： The most popularly used fin types in compact heat exchangers are the serrated fins, wavy fins, louvered fins and plain fins. Amongst these fin types the serrated fins assume lot of importance due to its enhanced thermo-hydraulic performance. Thermo-hydraulic design of CHEs （Compact heat exchangers） is strongly dependent upon the predicted/measured dimensionless performance （Colburnj factor and Fanning friction vs. Reynolds number） of heat transfer surfaces. This paper describes the numerical analysis to study the heat transfer coefficient and friction factor of Serrated fins in water medium. CFD （Computational fluid dynamics） methodology has been used to develop the single phase water heat transfer coefficient and friction factor correlations for serrated fins using ANSYS Fluent 14.5. The results are compared with previous air-cooled models and experimental results of water. The water cooled CFD analysis results shows that the Prandtl number has a large effect on the Nusselt number of the serrated fin geometry. Finally, the generalized correlations are developed for serrated fins taking all geometrical parameters into account. This numerical estimation can reduce the number of tests/experiments to a minimum for similar applications.
