单选题DNS协议的功能是（ ）。
单选题进程P1、P2、P3、P4、P5和P6的前趋图如下所示：若用PV操作控制进程PI、P2、P3、P4、P5和P6并发执行的过程，则需要设置7个信号量S1、S2、S3、S4、S5、S6和S7，且信号量S1~S7的初值都等于零。如下的进程执行图中，a和b处应分别填写（）；c和d处应分别填写（），e和f处应分别填写（）。
单选题Requirements validation is the process of checking that requirements actually define the system that the customer really wants. It overlaps with analysis as it is concerned with finding problems with the requirements. Requirements validation is important because errors in a requirements document can lead to extensive rework costs when these problems are discovered during development or after the system is in service. The cost of fixing a requirements problem by making a system change is usually much greater than repairing design or coding errors. The reason for this is that a change to the requirements usually means that the system design and implementation must also be changed. Furthermore, the system must then be re-tested.During the requirements validation process, different types of checks should be carried out on the requirements in the requirements document. These checks include:1.( ): A user may think that a system is needed to perform certain function. However, further thought and analysis may identify additional or different functions that are required. Systems have diverse stakeholders with different needs and any set of requirements is inevitably a compromise across the stakeholder community.2.( ): Requirements in the document should not conflict. That is, there should not be contradictory constraints or different descriptions of the same system function.3.( ): The requirements document should include requirements that define all functions and the constraints intended by the system user.4. Realism checks: Using knowledge of existing technology, the requirements should be checked to ensure that they can actually be implemented. These checks should also take account of the（ ）for the system development.5. Verifiability: To reduce the potential for dispute between customer and contractor, system requirements should always be written so that they are verifiable. This means that you should be able to write a set of tests that can demonstrate that the delivered system meets each specified ( ).
单选题某地天然气输送管线网络图如下，每段管线旁边数字表示输气能力（单位：万立方米/小时）。根据该图，从源s到目的地T的最大输气能力为（）位：万立方米/小时。
单选题进程P1、P2、P3、P4、P5和P6的前趋图如下所示：若用PV操作控制进程PI、P2、P3、P4、P5和P6并发执行的过程，则需要设置7个信号量S1、S2、S3、S4、S5、S6和S7，且信号量S1~S7的初值都等于零。如下的进程执行图中，a和b处应分别填写（）；c和d处应分别填写（），e和f处应分别填写（）。
单选题某乡有7个小山村A~G,村与村之间有小路可加宽修建公路的路线如下图所示（路边的数字表示路长的公里数）。为实现村村通公路，修建公路总长至少（）公里，若在（）村新建一所中学，则可以使人们从离它最远的村到该校所走的优化路线最短。
单选题工作流参考模型（Workflow Reference Model， WRM）包含6个基本模块，分别是（ ）、工作流引擎、流程定义工具、（ ）、调用应用和管理监控工具。
单选题在软件逆向工程的相关概念中，（ ）是指借助工具从已有程序中抽象出有关数据设计、总体结构设计和过程设计等方面的信息；（ ）指不仅从现有系统中恢复设计信息，而且使用该信息去改变或重构现有系统，以改善其整体质量。
单选题Requirements validation is the process of checking that requirements actually define the system that the customer really wants. It overlaps with analysis as it is concerned with finding problems with the requirements. Requirements validation is important because errors in a requirements document can lead to extensive rework costs when these problems are discovered during development or after the system is in service. The cost of fixing a requirements problem by making a system change is usually much greater than repairing design or coding errors. The reason for this is that a change to the requirements usually means that the system design and implementation must also be changed. Furthermore, the system must then be re-tested.During the requirements validation process, different types of checks should be carried out on the requirements in the requirements document. These checks include:1.( ): A user may think that a system is needed to perform certain function. However, further thought and analysis may identify additional or different functions that are required. Systems have diverse stakeholders with different needs and any set of requirements is inevitably a compromise across the stakeholder community.2.( ): Requirements in the document should not conflict. That is, there should not be contradictory constraints or different descriptions of the same system function.3.( ): The requirements document should include requirements that define all functions and the constraints intended by the system user.4. Realism checks: Using knowledge of existing technology, the requirements should be checked to ensure that they can actually be implemented. These checks should also take account of the（ ）for the system development.5. Verifiability: To reduce the potential for dispute between customer and contractor, system requirements should always be written so that they are verifiable. This means that you should be able to write a set of tests that can demonstrate that the delivered system meets each specified ( ).
单选题（ ）属于公钥加密算法。
单选题IP报文首部不包含（ ）
单选题Requirements validation is the process of checking that requirements actually define the system that the customer really wants. It overlaps with analysis as it is concerned with finding problems with the requirements. Requirements validation is important because errors in a requirements document can lead to extensive rework costs when these problems are discovered during development or after the system is in service. The cost of fixing a requirements problem by making a system change is usually much greater than repairing design or coding errors. The reason for this is that a change to the requirements usually means that the system design and implementation must also be changed. Furthermore, the system must then be re-tested.During the requirements validation process, different types of checks should be carried out on the requirements in the requirements document. These checks include:1.( 71 ): A user may think that a system is needed to perform certain function. However, further thought and analysis may identify additional or different functions that are required. Systems have diverse stakeholders with different needs and any set of requirements is inevitably a compromise across the stakeholder community.2.( 72 ): Requirements in the document should not conflict. That is, there should not be contradictory constraints or different descriptions of the same system function.3.( 73 ): The requirements document should include requirements that define all functions and the constraints intended by the system user.4. Realism checks: Using knowledge of existing technology, the requirements should be checked to ensure that they can actually be implemented. These checks should also take account of the（ 74 ）for the system development.5. Verifiability: To reduce the potential for dispute between customer and contractor, system requirements should always be written so that they are verifiable. This means that you should be able to write a set of tests that can demonstrate that the delivered system meets each specified ( 75 ).
单选题根据历史数据和理论推导可知，某应用中，随机变量s的分布密度函数为f（x）=3x^2, （0x1）。 这意味着，当Ax充分小时，随机变量S落在区间（x,x+ox）内的概率约等于f（x）Ax。为此，开发该应用的仿真系统时，可用（ ）来模拟该随机变量，其中，r.2.3...为计算机逐个产生的、均匀分布在（0,1）区间内的互相独立的伪随机数。
单选题基于模型的系统工程作为一种（ ），为了应对基于文档的传统系统工程工作模式在复杂产品和系统研发时面临的挑战，以逻辑连贯一致的多视角系统模型为桥梁和框架，实现跨领域模型的可追踪、可验证和动态关联，驱动人工系统生存周期内各阶段和各层级内的系统工程过程和活动，使其可管理、可复现、可重用，进而打破专业壁垒破解设计和工艺、研发和制造、研制和使用维护的分离，极大地提高沟通协同效率，现以模型驱动的方法来采集、捕获和提炼数据、信息和知识。
声卡中常采用Wave音效合成和MIDI音效合成来播放声音，其中MIDI音效合成有(48)两种方式。
为了验证新机器的指令系统，在一台计算机上依靠运行程序的办法来解释执行另一个计算机的指令，这称(7)。
微机A和微机B采用同样的CPU，微机A的主频为800MHz而微机B为 1200MHz。若微机A平均指令执行速度为40MIPS，则微机A的平均指令周期为(11)ns，微机B的平均指令执行速度为(12)MIPS。
131-45=53在(75)进制下成立。
操作系统主要的性能参数有(48)、(49)和(50)等。(48)指的是单位时间内系统处理的作业量。(49)指的是从作业或命令的输入到其结束的间隔时间，在分析性能时常用其倒数。(50)指的是在一个给定时间内，系统的一个指定成分被使用的时间比例。操作系统的保护主要包括存储保护、程序保护和文件与数据保护等。采用存取权限控制方法时，任一需保护的客体，都对应于一个二元组((51)，(52))，其中(51)表示用户、进程或用户组、进程组。
用UML建立业务模型是理解企业业务过程的第一步。业务人员扮演业务中的角色及其交互方式，例如航空公司的售票员是业务人员，电话售票员也是业务人员，他们之间的关系是(32)。在UML中，用(33)表示企业业务的工作流。这种图显示工作流中的步骤、决策点，以及完成每一步骤的角色和对象。