Gap acceptance theory is broadly used for evaluating unsignalized intersections in developed coun tries. Intersections with no specific priority to any move ment, known as uncontrolled intersections, are common in Ind...Gap acceptance theory is broadly used for evaluating unsignalized intersections in developed coun tries. Intersections with no specific priority to any move ment, known as uncontrolled intersections, are common in India. Limited priority is observed at a few intersections, where priorities are perceived by drivers based on geom etry, traffic volume, and speed on the approaches of intersection. Analyzing such intersections is complex because the overall traffic behavior is the result of drivers, vehicles, and traffic flow characteristics. Fuzzy theory has been widely used to analyze similar situations. This paper describes the application of adaptive neurofuzzy interface system （ANFIS） to the modeling of gap acceptance behavior of rightturning vehicles at limited priority Tintersections （in India, vehicles are driven on the left side of a road）. Field data are collected using video cameras at four Tintersections having limited priority. The data extracted include gap/lag, subject vehicle type, conflicting vehicle type, and driver＇s decision （accepted/rejected）. ANFIS models are developed by using 80 % of the extracted data （total data observations for major road right turning vehicles are 722 and 1,066 for minor road right turning vehicles） and remaining are used for model vali dation. Four different combinations of input variables are considered for major and minor road right turnings sepa rately. Correct prediction by ANFIS models ranges from 75.17 % to 82.16 % for major road right turning and 87.20 % to 88.62 % for minor road right turning. Themodels developed in this paper can be used in the dynamic estimation of gap acceptance in traffic simulation models.展开更多
Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Applicati...Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Application Specific Integrated Circuit (ASIC) as an example,this article analyzes several typical issues about packet receiving and sending by the CPU in a multi-progress environment,including CPU load,software and hardware queue settings,and communication mechanism between CPU and the switch chip. This article gives solutions to these issues mentioned above. The solutions are applicable to Network Processor (NP) issues as well.展开更多
Based on the high integration and low profile application requirements of phased array systems, a Ku band 64-element tile type transceiver component was developed. Through the high-density integrated 3D design concept...Based on the high integration and low profile application requirements of phased array systems, a Ku band 64-element tile type transceiver component was developed. Through the high-density integrated 3D design concept, the 64-element transceiver channels are arranged in a rectangular grid array, and the functional circuits are horizontally arranged and vertically integrated, achieving the low profile characteristics of the components. Detailed introductions were provided on the key circuit design, structural design, and thermal design of the components. Through physical testing, the single channel receiving gain of the transceiver component is ≥6 dB, and the noise figure is ≤3.5 dB;Single channel transmission gain ≥ 4 dB, transmission saturation output power ≥ 22 dBm;Each channel can independently achieve 6-bit phase shift and 4-bit attenuation functions. The phase consistency of 64 channels is better than 7°, and the amplitude consistency is better than 0.6 dB. The component size is 100 mm × 84 mm × 13.1 mm, with a mass of less than 150 g. This transceiver component has a standardized architecture and can flexibly achieve large-scale array expansion.展开更多
基金partially funded by Department of Science and Technology (DST), Govt. of Indiaproject SR/ FTP/ETA-61/2010
文摘Gap acceptance theory is broadly used for evaluating unsignalized intersections in developed coun tries. Intersections with no specific priority to any move ment, known as uncontrolled intersections, are common in India. Limited priority is observed at a few intersections, where priorities are perceived by drivers based on geom etry, traffic volume, and speed on the approaches of intersection. Analyzing such intersections is complex because the overall traffic behavior is the result of drivers, vehicles, and traffic flow characteristics. Fuzzy theory has been widely used to analyze similar situations. This paper describes the application of adaptive neurofuzzy interface system （ANFIS） to the modeling of gap acceptance behavior of rightturning vehicles at limited priority Tintersections （in India, vehicles are driven on the left side of a road）. Field data are collected using video cameras at four Tintersections having limited priority. The data extracted include gap/lag, subject vehicle type, conflicting vehicle type, and driver＇s decision （accepted/rejected）. ANFIS models are developed by using 80 % of the extracted data （total data observations for major road right turning vehicles are 722 and 1,066 for minor road right turning vehicles） and remaining are used for model vali dation. Four different combinations of input variables are considered for major and minor road right turnings sepa rately. Correct prediction by ANFIS models ranges from 75.17 % to 82.16 % for major road right turning and 87.20 % to 88.62 % for minor road right turning. Themodels developed in this paper can be used in the dynamic estimation of gap acceptance in traffic simulation models.
文摘Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Application Specific Integrated Circuit (ASIC) as an example,this article analyzes several typical issues about packet receiving and sending by the CPU in a multi-progress environment,including CPU load,software and hardware queue settings,and communication mechanism between CPU and the switch chip. This article gives solutions to these issues mentioned above. The solutions are applicable to Network Processor (NP) issues as well.
文摘Based on the high integration and low profile application requirements of phased array systems, a Ku band 64-element tile type transceiver component was developed. Through the high-density integrated 3D design concept, the 64-element transceiver channels are arranged in a rectangular grid array, and the functional circuits are horizontally arranged and vertically integrated, achieving the low profile characteristics of the components. Detailed introductions were provided on the key circuit design, structural design, and thermal design of the components. Through physical testing, the single channel receiving gain of the transceiver component is ≥6 dB, and the noise figure is ≤3.5 dB;Single channel transmission gain ≥ 4 dB, transmission saturation output power ≥ 22 dBm;Each channel can independently achieve 6-bit phase shift and 4-bit attenuation functions. The phase consistency of 64 channels is better than 7°, and the amplitude consistency is better than 0.6 dB. The component size is 100 mm × 84 mm × 13.1 mm, with a mass of less than 150 g. This transceiver component has a standardized architecture and can flexibly achieve large-scale array expansion.
