题目内容

（55)关系模式R 的规范化程度最高达到
A）1NF
B）2NF
C）3NF
D）4NF

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● Although a given waveform. may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of （71） . This, in turn, limits the data rate that can be carried on the transmission （72） . Asquare wave has an infinite number of frequency components and hence an infinite （73） . However, the peak amplitude of the kth frequency component, kf, is only 1/k, so most of the （74） in this waveform. is in the first few frequency components. In general, any digital waveform. will have （75） bandwidth. If we attempt to transmit this waveform. as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.
（71）A. frequencies B. connections C. diagrams D. resources
（72）A. procedure B. function C. route D. medium
（73）A. source B. bandwidth C. energy D. cost
（74）A. frequency B. energy C. amplitude D. phase
（75）A. small B. limited C. infinite D. finite

（24）下面是某路由器的DHCP配置信息
ip dhcp excluded-address 182.105.246.2 182.105.246.10
!
ip dhcp poll 246
network 182.105.246.0 255.255.255.0
default-router 182.105.246.1
domain-name pku.edu.cn
dns-sever 182.105.129.26 182.105.129.27 222.112.7.13
lease 0 5
根据上述信息，DHCP客户端不可能从服务器获得的IP地址是

A. 182.105.246.5
B. 182.105.246.11
C. 182.105.246.192
D. 182.105.246.254

（60）下列关于数据仓库的叙述中，哪一条是不正确的？

A. 数据仓库概念于1992年由W.H.Inmon提出
B. 数据仓库的数据是反映历史变化的
C. 能够模式化为维属性和度量属性的数据统称为多维数据
D. 数据仓库的操作基于多维数据模型,维属性是决策者所关心的具有实际意义的数量

（42）数据字典又称为
A）数据模型
B）系统目录
C）系统模型
D）用户口令