单选题设关系模式RU,F, U={A1，A2，A3，A4}，函数依赖集F={A1→A2，A1→A3 ，A2→A4}，关系R的候选码是作答此空。下列结论错误的是 。

单选题某单位网站首页被恶意篡改，应部署( )设备阻止恶意攻击。

单选题We initially described SOA without mentioning Web s ervices, and vice versA. This is because they are ortho gonal: service-orientation is an architectural () whil e Web services are an implementation ( ).The two can be used together, and they frequently are, but they are not mutually dependent.For example, although it is widely considered to be a distributed-computing solution,SOA can be applied to advantage in a single system,where services might be individual processes with well-defined ( ) that communicate using local channels,or in a self-contained cluster, where they might communicate across a high -speed interconnect.Similarly, while Web services are(回答此处 ) as the basis for a service-oriented environment, there is nothing in their definition that requires them to embody the SOA p rinciples. While( )is often held up as a key characte ristic of Web services,there is no technical reason that they should be stateless-that would be a design choi ce of the developerwhich may be dictated by the arc hitectural style of the environment in which the servic e is intended to participate.

单选题We initially described SOA without mentioning Web s ervices, and vice versA. This is because they are ortho gonal: service-orientation is an architectural (回答此处) whil e Web services are an implementation ( ).The two can be used together, and they frequently are, but they are not mutually dependent.For example, although it is widely considered to be a distributed-computing solution,SOA can be applied to advantage in a single system,where services might be individual processes with well-defined ( ) that communicate using local channels,or in a self-contained cluster, where they might communicate across a high -speed interconnect.Similarly, while Web services are( ) as the basis for a service-oriented environment, there is nothing in their definition that requires them to embody the SOA p rinciples. While( )is often held up as a key characte ristic of Web services,there is no technical reason that they should be stateless-that would be a design choi ce of the developerwhich may be dictated by the arc hitectural style of the environment in which the servic e is intended to participate.

单选题在地址栏中输入www.abc.com，浏览器默认的应用层协议是（）。

单选题Telnet协议是一种( )的远程登录协议。

单选题M公司将其开发的某软件产品注册商标为S，为确保公司在市场竞争中占据地位，M公司对员工进行了保密约束，此情形下，该公司不享有( )。

单选题包过滤防火墙对 的数据报文进行检查。

单选题面向对象分析时，执行的活动顺序通常是（）。

单选题采用面向对象方法分析时，首先要在应用领域中按自然存在的实体认定对象，即将自然存在的“( )”作为一个对象。

单选题（）是对稀疏矩阵进行压缩存储的方式

单选题SQL是一种数据库结构化查询语言，SQL注入攻击的首要目标是（）。

单选题下列认证方式安全性较低的是( )。

单选题某种机器的浮点数表示格式如下(允许非规格化表示)。若阶码以补码表示，尾数以原码表示，则1000100000000001表示的浮点数是()。

单选题Designing object -oriented software is hard,and designing 作答此空object -oriented software is even harder.You must find pertinent相关的objects,factor them into class at the right granularity,define class in

单选题在磁盘上存储数据的排列方式会影响IO服务的总时间。假设每个磁道被划分成10个物理块，每个物理块存放1个逻辑记录。逻辑记录R1,R2,.....,R10存放在同一个磁道上，记录的排列顺序如下表所示。假定磁盘的旋转速度为10ms/周，磁头当前处在R1的开始处。若系统顺序处理这些记录，使用单缓冲区，每个记录处理时间为2ms,则处理这10个记录的最长时间为(作答此空);若对存储数据的排列顺序进行优化，处理10个记录的最少时间为()。

单选题以下对于路由协议的叙述中，错误的是 ）。

单选题在单处理机计算机系统中，有1台打印机、1台扫描仪，系统采用先来先服务调度算法。假设系统中有进程P1、P2、P3、P4，其中P1为运行状态，P2为就绪状态，P3等待打印机，P4等待扫描仪。此时，若P1释放了扫描仪，则进程P1、P2、P3、P4的状态分别为 。