由于汽车智能化、网联化的进一步发展,车载以太网在汽车领域得到越来越广泛的应用。目前乘用车已经逐步采用UDS on DoIP技术方案,国内未见商用车采用UDS on DoIP技术的报道。文章主要介绍DoIP数据格式和诊断流程,并着重介绍在商用车领...由于汽车智能化、网联化的进一步发展,车载以太网在汽车领域得到越来越广泛的应用。目前乘用车已经逐步采用UDS on DoIP技术方案,国内未见商用车采用UDS on DoIP技术的报道。文章主要介绍DoIP数据格式和诊断流程,并着重介绍在商用车领域基于DoIP诊断路由应用及测试、刷写应用及测试和UDS诊断测试。展开更多
The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power ...The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power and pulse width influence on SNR is studied on the theoretical derivation and analysis,and the results show that the higher the peak power can realize the greater the signal-to-noise ratio of coherent Doppler wind lidar.But when the peak power is too large,the laser pulse may appear nonlinear phenomenon,which cause the damage of the laser.So,the peak power must be less than the stimulated brillouin scattering power threshold.Increasing the pulse width can make the laser device to output more energy,but it will also make the spatial resolution lower,and the influence of turbulence on SNR will be greater.After a series of simulation analyses,it can be concluded that when the peak power is 650W and the pulse width is 340ns,the SNR of the system can be maximized.In addition,the coherent Doppler wind lidar system is set up to carry out corresponding experimental verification.The experimental results are consistent with the theoretical analysis and simulation,which verifies the correctness of the theoretical analysis and simulation results.It provides theoretical basis and practical ex-perience for the design of laser transmitting pulse in coherent Doppler wind lidar system.展开更多
To further increase the throughput of wireless multi-hop networks,a distributed scheduling method is proposed,which takes physical interference model into account.It is assumed that nodes in the network can perform ph...To further increase the throughput of wireless multi-hop networks,a distributed scheduling method is proposed,which takes physical interference model into account.It is assumed that nodes in the network can perform physical carrier sensing,and the carrier sensing range can be set to different values.In the traditional carrier sensing mechanism,the carrier sensing range is computed under the protocol interference model,which is not accurate.Here the optimal carrier sensing range with physical interference model is achieved.Each sending node implements the distributed approach in three phases at each time slot,and all the concurrent transmissions are interference free.Good performance can be achieved under this scheduling approach.The approximation ratio of the distributed method to the optimal one is also proved.展开更多
文摘由于汽车智能化、网联化的进一步发展,车载以太网在汽车领域得到越来越广泛的应用。目前乘用车已经逐步采用UDS on DoIP技术方案,国内未见商用车采用UDS on DoIP技术的报道。文章主要介绍DoIP数据格式和诊断流程,并着重介绍在商用车领域基于DoIP诊断路由应用及测试、刷写应用及测试和UDS诊断测试。
文摘The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power and pulse width influence on SNR is studied on the theoretical derivation and analysis,and the results show that the higher the peak power can realize the greater the signal-to-noise ratio of coherent Doppler wind lidar.But when the peak power is too large,the laser pulse may appear nonlinear phenomenon,which cause the damage of the laser.So,the peak power must be less than the stimulated brillouin scattering power threshold.Increasing the pulse width can make the laser device to output more energy,but it will also make the spatial resolution lower,and the influence of turbulence on SNR will be greater.After a series of simulation analyses,it can be concluded that when the peak power is 650W and the pulse width is 340ns,the SNR of the system can be maximized.In addition,the coherent Doppler wind lidar system is set up to carry out corresponding experimental verification.The experimental results are consistent with the theoretical analysis and simulation,which verifies the correctness of the theoretical analysis and simulation results.It provides theoretical basis and practical ex-perience for the design of laser transmitting pulse in coherent Doppler wind lidar system.
基金Supported by the National Basic Research Program of China(No.2007CB307105)the National Natural Science Foundation of China(No.60932005)
文摘To further increase the throughput of wireless multi-hop networks,a distributed scheduling method is proposed,which takes physical interference model into account.It is assumed that nodes in the network can perform physical carrier sensing,and the carrier sensing range can be set to different values.In the traditional carrier sensing mechanism,the carrier sensing range is computed under the protocol interference model,which is not accurate.Here the optimal carrier sensing range with physical interference model is achieved.Each sending node implements the distributed approach in three phases at each time slot,and all the concurrent transmissions are interference free.Good performance can be achieved under this scheduling approach.The approximation ratio of the distributed method to the optimal one is also proved.
