Congestion control for packets sent on a network is important for DAQ systems that contain an event builder using switching network technologies.Quality of Service(QoS) is a technique for congestion control.Recent Lin...Congestion control for packets sent on a network is important for DAQ systems that contain an event builder using switching network technologies.Quality of Service(QoS) is a technique for congestion control.Recent Linux releases provide QoS in the kernel to manage network traffic.We have analyzed the packet-loss and packet distribution for the event builder prototype of the Atlas TDAQ system.We used PC/Linux with Gigabit Ethernet network as the testbed.The result showed that QoS using CBQ and TBF eliminated packet loss on UDP/IP transfer while the UDP/IP transfer in best effort made lots of packet loss.The result also showed that the QoS overhead was small.We concluded that QoS on Linux performed efficiently in TCP/IP and UDP/IP and will have an important role of the Atlas TDAQ system.展开更多
A series of software has been developed for small-scale data acquisition and analysis systems.Various classes were written un C++ and partly in Java,and a Private protocol was introduced for object persistency.A demon...A series of software has been developed for small-scale data acquisition and analysis systems.Various classes were written un C++ and partly in Java,and a Private protocol was introduced for object persistency.A demonstrationn system was built and the performance was tested in a beam test at KEK-PS.展开更多
Water surface is one of the most important components of landscape scenes. When rendering spacious water surface such as that of the lakes and reservoirs, aliasing and/or moire artifacts frequently occur in the region...Water surface is one of the most important components of landscape scenes. When rendering spacious water surface such as that of the lakes and reservoirs, aliasing and/or moire artifacts frequently occur in the regions far from the viewpoint. This is because water surface consists of stochastic water waves which are usually modeled by periodic bump mapping. The incident rays on the water surface are actually scattered by the bumped waves, and the reflected rays at each sample point are distributed in a solid angle. To get rid of the artifacts of moire pattern, we estimate this solid angle of reflected rays and trace these rays. An image-based accelerating method is adopted so that the contribution of each reflected ray can be quickly obtained without elaborate intersection calculation. We also demonstrate anti-aliased shadows of sunlight and skylight on the water surface. Both the rendered images and animations show excellent effects on the water surface of a reservoir.展开更多
文摘Congestion control for packets sent on a network is important for DAQ systems that contain an event builder using switching network technologies.Quality of Service(QoS) is a technique for congestion control.Recent Linux releases provide QoS in the kernel to manage network traffic.We have analyzed the packet-loss and packet distribution for the event builder prototype of the Atlas TDAQ system.We used PC/Linux with Gigabit Ethernet network as the testbed.The result showed that QoS using CBQ and TBF eliminated packet loss on UDP/IP transfer while the UDP/IP transfer in best effort made lots of packet loss.The result also showed that the QoS overhead was small.We concluded that QoS on Linux performed efficiently in TCP/IP and UDP/IP and will have an important role of the Atlas TDAQ system.
文摘A series of software has been developed for small-scale data acquisition and analysis systems.Various classes were written un C++ and partly in Java,and a Private protocol was introduced for object persistency.A demonstrationn system was built and the performance was tested in a beam test at KEK-PS.
文摘Water surface is one of the most important components of landscape scenes. When rendering spacious water surface such as that of the lakes and reservoirs, aliasing and/or moire artifacts frequently occur in the regions far from the viewpoint. This is because water surface consists of stochastic water waves which are usually modeled by periodic bump mapping. The incident rays on the water surface are actually scattered by the bumped waves, and the reflected rays at each sample point are distributed in a solid angle. To get rid of the artifacts of moire pattern, we estimate this solid angle of reflected rays and trace these rays. An image-based accelerating method is adopted so that the contribution of each reflected ray can be quickly obtained without elaborate intersection calculation. We also demonstrate anti-aliased shadows of sunlight and skylight on the water surface. Both the rendered images and animations show excellent effects on the water surface of a reservoir.
