（1）越高，屏幕上图像的闪烁感越小，图像越稳定，视觉效果也越好。当前PC中该指标大多采用（2）Hz。空白（1）处应选择（）

A.88

B.75

C.65

D.55

共用题干题AstuteserviceprovidersrealizethatthecontinuedsupportoflegacyX.25andasynchronousnetworkelementusingseparateoperationsnetworkiscost(16).Forexample,themaintenanceofmultiplenetworkscanrequireadditionalstaff.Often,thisstaffmustbetrainedonmultiplevendortechnologies,sometimesrequiringparallelgroupsspecializingineach(17).Hence,additionalmaintenanceproceduresmustbemaintainedandadministrativerecordsare(18).Theduplicationoftransportfacilitiestocarry(19)networktrafficisaninefficientuseofresources.Andnotsurprisingly,moretechnologiesinstalledinacentralofficemeansthenecessityformorephysicalspace,andanincreaseinpowerconnectionsandpowerconsumptionmigrationofthese(20)networkelementstoIP-basedDCnsisalogicalstrategy.

空白处（19）应选择（）

A.overlook

B.overlie

C.overlay

D.overleap

共用题干题AstuteserviceprovidersrealizethatthecontinuedsupportoflegacyX.25andasynchronousnetworkelementusingseparateoperationsnetworkiscost(16).Forexample,themaintenanceofmultiplenetworkscanrequireadditionalstaff.Often,thisstaffmustbetrainedonmultiplevendortechnologies,sometimesrequiringparallelgroupsspecializingineach(17).Hence,additionalmaintenanceproceduresmustbemaintainedandadministrativerecordsare(18).Theduplicationoftransportfacilitiestocarry(19)networktrafficisaninefficientuseofresources.Andnotsurprisingly,moretechnologiesinstalledinacentralofficemeansthenecessityformorephysicalspace,andanincreaseinpowerconnectionsandpowerconsumptionmigrationofthese(20)networkelementstoIP-basedDCnsisalogicalstrategy.

空白处（20）应选择（）

A.raditional

B.dominancy

C.redundancy

D.legacy

共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.

空白处（21）应选择（）

A.data

B.state

C.signal

D.control

共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.

空白处（22）应选择（）

A.give-up

B.abandon

C.quit

D.connection

共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.

空白处（23）应选择（）

A.reset

B.acknowledgment

C.sequence

D.synchroizer

共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.

空白处（24）应选择（）

A.stops

B.restarts

C.expires

D.abandons

共用题干题Whenthesystemuponwhichatransportentityisrunningfailsandsubsequentlyrestarts,the(21)informationofallactiveconnectionsislost.Theaffectedconnectionsbecomehalf-open,asthesidethatdidnotfaildoesnotyetrealizetheproblem.Thestillactivesideofahalf-openconnectionscanclosetheconnectionusinga(22)timer.Thistimermeasuresthetimethetransportmachinewillcontinuetoawaitan(23)ofatransmittedsegmentafterthesegmenthasbeenretransmittedthemaximumnumberoftimes.Whenthetimer(24),thetransportentityassumesthateithertheothertransportentityortheinterveningnetworkhasfailed.Asaresult,thetimerclosestheconnection,andsignalsanabnormalclosetotheTSuser.Intheeventthatatransportentityfailsandquicklyrestarts,half-openconnectionscanbeterminatedmorequicklybytheuseoftheRSTsegment,thefailedsidereturnsanRSTitoeverysegmentithatitreceives.WhentheRSTireachestheotherside,itmustbecheckedforvaliditybasedonthe(25)numberi,astheRSTcouldbeinresponsetoanoldsegment.Iftheresetisvalid,thetransportentityperformsanabnormaltermination.

空白处（25）应选择（）

A.sequence

B.acknowledgment

C.connection

D.message

A.Shift

B.Ctrl

C.Alt

D.Tab

【问题1】　　请用400字以内文字，从安全方面，特别针对谢工所列举的建设防火墙、入侵检测、病毒扫描、安全扫描、日志审计系统进行分析，评论这些措施能够解决的问题和不能解决的问题。【问题2】　　请用300字以内文字，主要从认证、机密性、完整性和抗抵赖性方面，论述王工的建议在安全上有哪些优点。【问题3】　　对于复杂系统的设计与建设，在不同阶段都有很多非常重要的问题需要注意，既有技术因素阻力，又有非技术因素阻力。请结合工程的实际情况，用200字以内文字，简要说明使用PKI还存在哪些重要的非技术因素方面的阻力。

阅读以下关于电子政务系统安全体系结构的叙述，回答问题1～问题3。

博学公司通过投标，承担了某省级城市的电子政务系统，由于经费、政务应用成熟度、使用人员观念等多方面的原因，该系统计划采用分阶段实施的策略来建设，最先建设急需和重要的部分。在安全建设方面，先投入一部分资金保障关键部门和关键信息的安全，之后在总结经验教训的基础上分两年逐步完善系统。因此，初步考虑使用防火墙、入侵检测、病毒扫描、安全扫描、日志审计、网页防篡改、私自拨号检测、PKI技术和服务等保障电子政务的安全。

由于该电子政务系统涉及政府安全问题，为了从整个体系结构上设计好该系统的安全体系，博学公司首席架构师张博士召集了项目组人员多次讨论。在一次关于安全的方案讨论会上，谢工认为由于政务网对安全性要求比较高，因此要建设防火墙、入侵检测、病毒扫描、安全扫描、日志审计、网页防篡改、私自拨号检测系统，这样就可以全面保护电子政务系统的安全。王工则认为谢工的方案不够全面，还应该在谢工提出的方案的基础上，使用PKI技术，进行认证、机密性、完整性和抗抵赖性保护。

【问题1】

请用400字以内文字，从安全方面，特别针对谢工所列举的建设防火墙、入侵检测、病毒扫描、安全扫描、日志审计系统进行分析，评论这些措施能够解决的问题和不能解决的问题。

【问题2】

请用300字以内文字，主要从认证、机密性、完整性和抗抵赖性方面，论述王工的建议在安全上有哪些优点。

【问题3】

对于复杂系统的设计与建设，在不同阶段都有很多非常重要的问题需要注意，既有技术因素阻力，又有非技术因素阻力。请结合工程的实际情况，用200字以内文字，简要说明使用PKI还存在哪些重要的非技术因素方面的阻力。