简介:Anoutsourcedatabaseisadatabaseserviceprovidedbycloudcomputingcompanies.Usingtheoutsourcedatabasecanreducethehardwareandsoftware'scostandalsogetmoreefficientandreliabledataprocessingcapacity.However,theoutsourcedatabasestillhassomechallenges.Iftheserviceproviderdoesnothavesufficientconfidence,thereisthepossibilityofdataleakage.Thedatamayhasuser'sprivacy,sodataleakagemaycausedataprivacyleak.Basedonthisfactor,toprotecttheprivacyofdataintheoutsourcedatabasebecomesveryimportant.Inthepast,scholarshaveproposedk-anonymitytoprotectdataprivacyinthedatabase.Itletsdatabecomeanonymoustoavoiddataprivacyleak.Butk-anonymityhassomeproblems,itisirreversible,andeasiertobeattackedbyhomogeneityattackandbackgroundknowledgeattack.Lateron,scholarshaveproposedsomestudiestosolvehomogeneityattackandbackgroundknowledgeattack.Buttheirstudiesstillcannotrecoverbacktotheoriginaldata.Inthispaper,weproposeadataanonymitymethod.Itcanbereversibleandalsopreventthosetwoattacks.Ourstudyisbasedontheproposedr-transform.Itcanbeusedonthenumerictypeofattributesintheoutsourcedatabase.Intheexperiment,wediscussedthetimerequiredtoanonymizeandrecoverdata.Furthermore,weinvestigatedthedefenseagainsthomogeneousattackandbackgroundknowledgeattack.Attheend,wesummarizedtheproposedmethodandfutureresearches.
简介:基于频率可重构原理设计的五频段天线,通过调节寄生单元和馈电线的长度来改变天线的局部结构,从而获得不同的工作频段。该天线可在470~770MHz,800~930MHz,934~960MHz,1854~1892MHz,2407~2509MHz五种频段之间实现可重构,覆盖了无线通信系统工作频段,各个状态具有较好的特性。在此基础上,搭建的能量收集器可以对接收到的信号能量进行收集,环境能量收集器系统包括可重构天线、匹配网络和整流升压。通过仿真软件ADS和HFSS对收集器各部分优化、仿真,仿真结果显示各部分性能良好,该收集器的灵敏度较高。最后经过实测,佐证了收集器的整体效率较高,最大收集效率可达58.6%。
简介:针对指挥所现有视音频系统与设备存在的问题,提出了一个基于云架构的统一视音频服务平台解决方案,论述了该平台软件体系结构、网络架构及其信息关系,分析了涉及的视频统一接入及图形处理器(GPU)虚拟化等关键技术,并给出了原型系统实际应用效果。最后总结了统一视音频服务平台对指挥所业务发展的意义。