简介:Thispaperaddressestheissueofreal-timedatatransmissioninvehiclestoroadside(V2R)environmentbythehybridcoordinationfunction(HCF)ofcontrolledchannelaccess(HCCA)specifiedbytheIEEE802.11pstandard.HCCAisoneofthemediumaccessmechanismsintheIEEE802.11standard,andusesthepollingschemesimilartothepointcoordinationfunction(PCF)toprovidereliablequalityofservice(QoS),whichmaycauseresourceovershootingandhightimeconsuming.ThispapertriestoimprovetheperformanceoftheHCCApollingschemeanddesignsnewdatatransmissionschedulingscheme.Thesimulationresultsoftheproposalarecomparedwiththoseofthestandardstrategy.SimulationresultsdemonstratethattheimprovedHCCAhaslowerdelay,lossrate,andhigherthroughputthanthoseofthestandardone.
简介:通过研究英国工商管理硕士协会对工商管理博士项目的认证要求,对我国今后设立工商管理博士专业学位提出三点建议:第一,开设DBA项目的学校或学院要有高质量的工商管理教育水平;第二,DBA项目要重视研究方法训练;第三。DBA项目应强调实践取向与应用导向。