单选题有关动态增量备份的描述正确的是 (8) 。
单选题ISO 9001-2000是ISO 9000系列标准的最新成果,它取代了 (24) 标准。
单选题以下显示器像素点距的规格中,最好的是 (12) 。
单选题项目管理工具中,将网络方法用于工作计划安排的评审和检查的是
________
。
单选题“授权”和“撤权”是DBS采用的
____
措施。
单选题
10.设二维数组F的行下标为1~5,列下标为0~8,F的每个数据元素均占4个字节。在按行存储的情况下,已知数据元素F[2,2]的第一个字节的地址是1044,则F[3,4]和F[4,3]的第一个字节的地址分别为{{U}}
(1) {{/U}}和{{U}} (2) {{/U}},而数组的第一个数据元素的第一个字节和数组最后一个元素的最后一个字节的地址分别为{{U}} (3) {{/U}}和{{U}}
(4) {{/U}}。 对一般的二维数组G而言,当{{U}} (5)
{{/U}}时,其按行存储的G[i,j]的地址与按列存储的G[j,i]的地址相同。
单选题在软件生存中,
30
阶段所占的工作量最大,约70%。
结构化分析方法产生的系统说明书由一套分层的
31
图、一本数据字典、一组说明以及补充材料组成。
软件的
32
一般由两次故障时间和故障平均恢复时间来度量。
采用
33
编写程序,可提高程序的可移植性。
仅根据规格说明书描述的程序功能来设计测试用例的方法称为
34
。
单选题在文件存储设备管理中,有三类常用的空闲块管理方法,即位图向量法、空闲块链表链接法和
________
。
单选题设关系只为第一范式,若它的每一非主属性都完全函数依赖于主码,则称R属于
____
。
单选题设R和S都是二元关系,那么与元组演算表达式t|R(t)∧(u)(S(u)∧u[1]≠t[2])不等价的关系代数表达式是)______。A.π1,2(σ2≠3(R×S))B.π1,2(σ2≠1(R×S))C.π1,2(RS)D.π3,4(σ1≠4(S×R))
单选题数据模型的3个要素是( )。 A) 数据结构、数据定义和完整性约束 B) 数据结构、数据操作和数据定义 C) 数据结构、数据定义和数据联系 D) 数据结构、数据操作和完整性约束
单选题While most recent attention in the AI field has been focused on expert system software, AI (66) has also seen dramatic advances. Activity in the past years was characterized by new low-cost, powerful Lisp machines, the introduction of AI workstations, Lisp compilers becoming available for all major professional and engineering workstations, and the personal computer emerging as a (67) . tool for expert system development. The next few years will see this technology evolves further. Because the (68) of an AI computer represents a sizable investment, companies should carefully (69) all options that are available as well as have a good idea of what the next generation of systems will offer in order to (70) the optimum system. This publication provides the information necessary to gain this understanding.
单选题设关系R和S的属性个数分别为2和3,那么RS等价于______。A.σ1<2(R×S)B.σ1<4(R×S)C.σ1<2(RS)D.σ1<4(RS)
单选题对由n个记录所组成的有序关键码排序时,下列各常用排序算法的平均比较次数分别是:二路归并排序为 (29) ,冒泡排序 (30) ,快速排序为 (31) 。其中,归并排序和快速排序所需要的辅助存储分别是 (32) 和 (33) 。
单选题MIDI文件是最常用的数字音频文件之一,MIDI是一种 (28) ,它是该领域国际上的一个 (29) 。
单选题下述任务中,不属于软件工程需求分析阶段的是
________
。
单选题相联存储器的访问方式是______。
单选题Programming is a (46) that has various engineering and (47) aspects. Although most of these aspects are interrelated, each of them covers a number of (48) and goals winch are very specific. The progress being made in teaching (49) is reflected by the fact that most (50) science curricula contain a broad spectrum of programming courses, each emphasizing a different aspect of programming.
单选题
{{U}}(13)
{{/U}}是一种静态结构描述工具,它是描述系统的模块结构,以及模块之间关系的一种静态结构。它不能像{{U}} (14)
{{/U}}那样,能够从系统流程的角度描述系统的动态特性。{{U}} (13)
{{/U}}能够全面地描述系统模块化的结果,以及各个模块的调用关系。在{{U}} (13)
{{/U}}上,模块的层次关系也是显而易见的。模块之间的调用关系包括{{U}} (15) {{/U}}和循环调用等多种类型,{{U}}
(13)
{{/U}}能够通过不同的标志来区分不同的调用类型。当然,这种调用关系仅仅限于描述系统模块之间的关系,而不能描述调用的动态特性。
单选题With the widespread use of the personal computer, many authorities in the field of (56) have pointed out the need for computer literacy. Unfortunately, there is no (57) agreement as to what the term "computer literacy" means. Some feel that computer literacy means knowing how to make the computer "compute"; that is knowing how to program computers in one or more programming languages. Others feel that knowing how to program is merely a small segment of computer literacy. These people (58) the major emphasis in schools should be on teaching how to effectively use the many software packages that are available. Still others suggest that computer literacy education is not required. They suggest that computers are being so rapidly integrated into our society that using a computer will be as (59) as using a telephone or a video tape recorder, and that special education will not be necessary. (60) of one's definition of computer literacy, it is recognized by most that learning to use a computer is indeed an important skill in modern society.