| 软件水平考试系统分析师易错题（2019/3/5） |
| 第1题：用户A通过计算机网络向用户B发消息，表示自己同意签订某个合同，随后用户A反悔不承认自己发过该条消息。为了防止这种情况发生，应采用( )
A、数字签名技术 B、消息认证技术 C、数据加密技术 D、身份认证技术 |
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| 第2、3、4题：用Huffman(霍夫曼)算法求带权的2，3，5，7，8的最优二叉树T，那么T的权为(2)
T中有(3)处树叶，共有(4)个结点 (2) A、45 B、50 C、55 D、60 (3) A、4 B、5 C、6 D、7 (4) A、6 B、7 C、8 D、9 |
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| 第5、6、7、8、9题：在形式语言中，方法G是一个四元组G=(VN，Vr，P，Z),其中VN为(6)。若方法G的产生式集P为： (1)Z→Bc (2)Z→Zc (3)B→Ab (4)B→Bb (5)A→Aa (6)A→a 则文法G是(7)文法，识别G的自动机为(8)。对于G来说，(9)为文法G可接受的字符串，(10)为文法G不可接受的字符串。
(6) A、状态标志符 B、开始符 C、语句集 D、非终结符集合 (7) A、短语 B、上下文有关 C、上下文无关 D、正则 (8) A、图灵机 B、下推自动机 C、有穷状态自动机 D、线性界限自动机 (9) A、aaabc B、acbb C、acbcab D、acbbca (10) A、abbcc B、acbc C、aaabc D、aabbccc |
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| 第10题：过原点做曲线y=ex的切线，则切线的方程为( )。
A、y=ex B、y=ex C、y=x D、y=ex/2 |
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| 第11、12、13、14、15题：In the following essay, each bland has four choices.Choose the best answer and write down on the answer sheet. With the implementation of (6) the so – called network has become a reality. The provision of such facilities is the most important part of the network requirements. However, in many applications the communicating computers may be of different types. This means that they may use different programming languages and, more importantly, different forms of (7) interface between user(application)program, normally referred to ,as application processes, and the underlying communication services may be (8). For example, one computer may be a small single-user computer, while another may be a large (9) system. In the earlier days of computer communication, these issues meant that only closed communities of computers (that is, from the same manufacturer) could communicate with each other in a meaningful way. IBM’s systems NetworkArchitecture (SNA、andDEC’sDigital NetworkArchitectureDNA、are just two examples of communication software packages produced by manufacturers to allow their systems to be intercormected together. These proprietary packages, however, of which there am still many inexistence, do not address the problem of universal interconnect ability, or open systems interconnection. In an attempt to alleviate this problem,(10) ,in the late 1970s,formulated a reference model to provide a common basis (or the coordination of standards developments and to allow existing and evolving standards activities to be placed into perspective with one another.
(6) A、communicationchannel B、protocols C、datachannel D、publiccommunication (7) A、database B、datarepresentation C、protocols D、datacommunication (8) A、same B、similar C、different D、dependent (9) A、multi-user B、client C、server D、full-user (10) A、DNA B、SNA C、theOSI D、theISO |
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