单选题In information theory, "information" is regarded as knowledge which reduces or removes (71) about the occurrence of a specific event from a given set of possible events. The concept "event" is to be understood as used in the theory of probability. For instance, an event may be the occurrence of a (72) character or word in a given message or in a given position of a message. In communication theory, channel is defined as that part of a communication system that connects the message source with the message sink. An encoder may be inserted between the message source and the input to the channel, and a (73) between the output of the channel and the message sink. Generally, these two units are not considered as being parts of the channel. In certain cases, however, they may be considered as pans of the message source and message sink, (74) . In information theory (75) to Shannon, the channel can be characterized by the set of conditional probabilities of occurrence of all the messages received at the message sink when a given message emanates from the message source.

单选题传统以太网采用的编码方式是 (63) 。

单选题根据McCabe环路复杂性度量，如图4-5所示的程序图的复杂度是{{U}}(31){{/U}}，对该程序进行路径覆盖测试，可得到的基本路径是{{U}}(32){{/U}}。

单选题系统交付用户使用了一段时间后发现，系统的某个功能响应非常慢

单选题若采用邻接矩阵来存储简单有向图，则其某一个顶点i 的入度等于该矩阵 （ ） 。

单选题与前两版相比，以下不属于VTPv3改进的是______。 A．支持扩展VLAN B．支持每端口配置 C．直接处理VLAN事务，是VTPv1和VTPv2的进一步改进 D．支持传播VLAN数据库和其他数据库类型

单选题设学生S、课程C、学生选课SC的关系模式分别为S(SNO,SNAME,SDEP,SAGE,SADDR)、C (CNO,CNAME,PCNO)以及SC(SNO,CNO,GRADE)，与关系代数表达式πSNO,SNAME,GRADE(σCNAME='数据库'(S＞＜SC＞＜C)等价的元组演算表达式为 (35) S(U)∧SC(V)∧C(W)∧ (36) ∧ (37) 。

单选题______一经接受并采用，或各方商定同意纳入经济合同中，就成为各方必须共同遵守的技术依据，具有法律上的约束性。 A．强制性标准 B．推荐性标准 C．国际标准 D．区域标准

单选题Flynn分类法基于信息流特征将计算机分成4类，其中______只有理论意义而无实例。

单选题一个故障已经被发现，而且也被排除了，为了检查修改是否引起了其他故障，这时应该进行 (19) 。

单选题我国标准分为国家标准、行业标准、地方标准和企业标准四类。根据标准的法律约束性，可分为强制性标准和推荐性标准。现已得到国家批准的《软件工程术语标准》(GB/T11457-89)属于______标准。

单选题改正在软件系统开发阶段已经发生而系统测试阶段清寒没有发现的错误，属于（ ）维护。

单选题在编译程序时，采用的对中间代码的优化方法中， (30) 是基于循环结构进行的优化处理。 ①合并已知量 ②删除归纳变量 ③删除多余运算 ④强度削弱 ⑤复写传播 ⑥代码外提

单选题归并排序采用的算法设计方法属于（ ） 。

单选题 Microsoft's COM is a software {{U}}(71) {{/U}} that allows applications to be built from binary software components. COM is the underlying architecture that forms the foundation for higher-level software services, like those provided by OLE. COM defines a binary standard for function calling between components, a way for components to dynamically discover the interfaces implemented by other components, and a mechanism to identify components and their interfaces uniquely. OLE is a compound {{U}}(72) {{/U}} standard developed by Microsoft. OLE makes it possible to create {{U}}(73) {{/U}} with one application and link or embed them in a second application. Embedded objects retain their original format and {{U}}(74) {{/U}} to the application that created them. Support for OLE is built into the Windows and MacOS Operating Systems. A {{U}}(75) {{/U}} compound document standard developed mainly by Apple and IBM is called OpenDoc.

单选题一棵非空二叉树中，叶子结点的数量等于度为2的结点数量加 (58) 。

单选题将双绞线制作成交叉线（一端按EIA/TIA 568A 线序，另一端按EIA/TIA 568B 线序），该双绞线连接的两个设备可为 （ ） 。

单选题继承是父类和子类之间共享数据和方法的机制。以下关于继承的叙述中，不正确的是______。有关下图中dolt()方法的叙述中，正确的是______。

单选题商品关系P(商品名，条形码，产地，价格)中的 (53) 属性可以作为该关系的主键。