问题 问答题

阅读以下关于软件复用技术应用的叙述,根据要求回答问题。
[说明]
随着政府职能的转型,XX行业职能主管部门(国家相关部委、各省、市的相关厅、局、委等)机构日趋精简,但随着国家现代化的发展,业务量反而越来越大。为保证本行业管理工作的质量和效率,实现企业资质审批管理信息化、网络化和电子化,提高了工作效率和质量,规范了业务处理流程,提高管理工作的广度、深度、力度和速度,更有效地为相关企业和业主提供服务,该行业主管部门委托FT软件开发公司开发一个XX行业管理信息系统。该系统由公共信息管理模块、系统管理维护模块、资质管理模块、企业信息管理模块和系统扩展接口模块等5大功能模块组成。
在该项目架构分析会上,FT公司高层领导提出,为了使那些公共功能模块比较容易地被其他电子政务项目所复用,应充分利用领域分析和软件复用的知识,采用基于可复用的软件开发方式,在这些公共模块的实现中保持高度的独立性,即在实现的具体细节上与XX行业国家部委(或者其他的政府机构)无关。

[问题3]
软件复用包括两个相关过程:可复用软件(构件)的开发;基于可复用软件(构件)的应用系统构造(集成和组装)。软件构件技术是软件复用的核心技术。结合你的系统架构设计经验,请用200字以内的文字简要说明可复用构件应具备哪些属性,并给予简要的解释。

答案

参考答案:构件(component)是指应用系统中可以明确辨识的构成成分。它是软件系统可替换的、物理的组成部分,它封装了实现体(实现某个职能),并提供了一组接口的实现方法。而可复用构件(Reusablecomponent)是指具有相对独立的功能和可复用价值的构件。软件构件技术是软件复用的核心技术。它是基于面向对象的,以即插即用型软构件概念为中心,通过构件组合来建立应用的体系。其主要研究内容包括构件获取、构件模型、构件描述语言、构件分类与检索、构件复合组装和构件标准化。
可复用构件应具备以下属性。
(1)有用性(Usefulness),构件必须提供有用的功能。
(2)可用性(Usability),构件必须易于理解和使用。
(3)质量(Quality),构件及其变形必须能正确工作。
(4)适应性(Adaptability),构件应该易于通过参数化等方式在不同语境中进行配置。
(5)可移植性(Portability),构件应能在不同的硬件运行平台和软件环境中工作。
(6)可变性(Variability),构件除了向复用者提供一些公共“特性”外,还要提供可变的“特性”。针对不同的应用系统,只需对其可变部分进行适当的调节,复用者要根据复用的具体需要,改造构件的可变“特性”,即进行“客户化”工作等。

阅读理解

Sales of laptop computers passed desktops in the U.S. for the first time ever this fall, according to market-research firm IDC. That's bad news for backs, necks and shoulders.

Laptops are bad for our body. When you work at a computer, the keyboard should be at elbow height and the monitor should be roughly at eye level, so you can sit well in a chair. But most users simply set their laptops on a desk or table. The keyboard is too high, which makes your arms reach up, your shoulders feel tired and your wrists bend down. The monitor is too low, which pulls your head and neck forward and down and your back may feel hurt.

That's OK if you use your laptop for a short time. But if you use one for hours without stopping – as do millions of college students, business travelers, telecommuters, video-gamers and growing numbers of office workers – your body may feel hurt. Ergonomics experts have warned about laptop problems for years. But people still like laptops better than the desktops. And they use laptops anywhere – in bed, on the floor – in all kinds of positions.

“How can a mouse or a keyboard hurt you?” says Thomas Caffrey, the founder of Myofactors LLC, “Wrong positions can be bad for your body. As time goes by, a wrong position can lead to pain in the neck, shoulders, back and arms, as well as headaches.”

小题1:When you work at a computer, the keyboard should be ________.

A.at elbow height

B.at eye height

C.on a desk

D.on a table小题2:The writer asks us not to use the laptop ________.

A.for a short time

B.to play video games

C.for hours without stopping

D.to buy things on the Internet小题3:From the passage, we know that laptop computers ________.

A.are not so popular as the desktops

B.are more popular than the desktops

C.are not bad for our body

D.have no mouse now小题4:Using a laptop in a wrong position may make ________.

A.people’s sight lower

B.people have cancer

C.people’s arm longer

D.people feel pain in the body小题5:According to the passage, which of the following is NOT true?

A.When you use a laptop, you should put your monitor at eye height.

B.Laptop computers sold more than desktops this autumn.

C.To keep healthy, you should use laptop computers.

D.Business travelers often use the laptop computers for a long time.

单项选择题