单选题信息工程方法把整个信息系统的开发过程划分为4个实施阶段,其自上而下的顺序是______。
单选题During the past years, intelligent technology has evolved (116) three generations. The first was characterized by tools such as prolog and OPS. prolog is a simple backward-chaining environment, and OPS is a simple forward-chaining environment. This led to the second generation of knowledge-engineering environments. Its goal was to model, prototype and construct (117) systems. All three generations were oriented toward generic (118) and represented generalized implementation environments for the construction of expert systems. knowledge bases and AI applications. Some of the solution-oriented products are also seamlessly integrated with generic knowledge-engineering environments, permitting end users to add (119) rules and objects, as well as predefined knowledge-based logic to address problems in manufacturing simulation. Marketplace orientation is rapidly (120) toward solution-oriented intelligent product environments. the fourth generation represents a new line of thinking and ' develop-merit by commercial fu-ms. will reduce the cost risk and development time associated with problem solving.
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单选题设指令由取指、分析、执行3个子部件完成,并且每个子部件的时间均为△t。若采用常规标量单流水线处理机(即该处理机的度为1),连续执行12条指令,共需 (81) △t。若采用度为4的超标量流水线处理机,连续执行上述12条指令,只需 (82) △t。
单选题图2-6示意了发送者利用非对称加密算法向接收者传送消息的过程,图中a和b处分别是______。
单选题管理的基本职能对于不同层次的管理,其重要性也不同。对于企业内的上层管理部门,______是最主要的职能。
单选题某数据处理流水线如图所示,若每隔3△t流入一个数据,连续处理4个数据。此数据处理流水线的实际吞吐率为{{U}}{{U}}10{{/U}}{{/U}}。此时该流水线的效率为{{U}}{{U}}11{{/U}}{{/U}}。
单选题假设一个I/O系统只有一个磁盘,每秒可以接收50个I/O请求,磁盘对每个I/O请求服务的平均时间是10ms,则I/O请求队列的平均长度是 (40) 个请求。 A.0 B.0.5 C.1 D.2
单选题In a public-key cryptosystem, (71) encrypted with the public key can only be deciphered with the private key from the same (72) . Conversely, (71) encrypted with the private key can be decrypted only with the public key. Users can make their public keys (73) available or place them at a key distribution center or others to access. However, the private key must be (74) safe. In public-key systems there's no (75) to find a safe channel for communicating a shared secret key.
单选题在异步通信中,每个字符包含1位起始位、7位数据位、1位奇偶位和2位终止位,每秒钟传送100个字符,则有效数据速率为 (36) 。
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单选题 (64) 不属于PKI CA认证中心的功能。
单选题如果主存容量为16MB,且按字节编址,则表示该主存地址至少应需要______位。
单选题关于可靠性,以下叙述中正确的是 (65) 。
单选题IP安全性(IP Security,IPSec)提供了在局域网、广域网和互联网中安全通信能力。关于IP安全性下列说法不正确的是 (32) 。
单选题计算机的存储系统采用分级存储体系的理论依据是 (11) 。目前,计算机系统中常用的三级存储体系是 (12) 。
单选题哈夫曼(Huffman)编码是一种频度相关压缩编码方法,属于 (8) 数据压缩,而对于声音和图像的压缩则通常采用 (9) 数据压缩方法,以达到更高的数据压缩比。
单选题假设信源是由q个离散符号S1,S2,…,Si…,sq所组成的符号集合,集合中的每个符号是独立的,其中任一个符号Si出现的概率为P(Si),并满足ΣP(Si)=1。那么符号Si含有的信息量I(Si)等于 (38) ,单位是 (39) 。
单选题System analysis is traditionally done top-down using structured analysis based on ______. Object-oriented analysis focuses on creation of models. The three types of the analysis model are ______. There are two substages of object-oriented analysis. ______ focuses on real-world things whose semantics the application captures. The object constructed in the requirement analysis shows the ______ of the real-world system and organizes it into workable pieces. ______ addresses the computer aspects of the application that are visible to users. The objects are those which can be expected to vary from time to time quite rapidly.