卧龙岗大学代写Assignment:软件工程师的原则

卧龙岗大学代写Assignment:软件工程师的原则

卧龙岗大学代写Assignment:软件工程师的原则

软件度量的基本目的是过程控制中的有效管理。由于度量强烈支持软件项目管理活动。他们涉及到管理的四个功能如下:

许多系统执行一个任务,通过一个单一的组件执行一个小的一部分,并将其结果到另一个组件在一个串行的方式。新组件然后执行一个小的任务,并继续传递它,直到任务完成。这是人们通常设计的程序和硬件设备。该解决方案可以是成本效益和优雅。正如Von Braun发现的,这使得它非常难以建立一个可靠的系统。这样的系统可以有他们的可靠性建模使用一些方程。因此,建立一个连续可靠的系统是非常困难和昂贵的。

例如,如果一个是建立一个串行系统的100个组成部分,其中每一个有一个可靠性。999的整体系统的可靠性将是0.999100 = 0.905。

通过利用冗余,系统组件,硬件或软件(提供的算法是不同的)可以提供一个提高可靠性。在最简单的情况下(失败的沉默的组件没有正确的投票)只有一个冗余组件必须工作,以保持系统的服务水平。

例如,考虑一个用4个相同的模块构建的系统。该系统将正常运行,至少提供一个模块是可操作的。如果每个模块的可靠性是。95,那么整个系统的可靠性是:

这样,可靠的系统可以建立尽管它的组成部分不可靠,虽然这种并行的成本可高。更复杂的系统模型,可以建立简单的串行和并行可靠性模型相结合。

卧龙岗大学代写Assignment:软件工程师的原则

The basic purpose of using software metrics is the effective management during the process control. Since Metrics strongly support software project management activities. They relate to the four functions of management as follows:

Many systems perform a task by having a single component perform a small part of it, and pass its result to another component in a serial fashion. The new component then performs a small piece of the task, and continues passing it along, until the task is completed. This is how people typically design programs, and hardware devices. The solutions can be cost effective and elegant. As Von Braun discovered, this makes it exceedingly difficult to build a reliable system. Such systems can have their reliability modeled using some equations. Thus building a serially reliable system is extraordinarily difficult and expensive.

For example, if one were to build a serial system with 100 components each of which had a reliability of .999 the overall system reliability would be 0.999100 = 0.905.

By utilizing redundancy, system component, hardware or software (provided the algorithms are diverse) can provide a boost in reliability. In the simplest case (fail silent components no correctness voting) only one of the redundant components must be working to maintain the system’s level of service.

For example, Consider a system built with 4 identical modules. The system will operate correctly provided at least one module is operational. If the reliability of each module is .95, then the overall system reliability is:

In this way, reliable system can be built despite the unreliability of its component parts, though the cost of such parallelism can be high. Models of more complex systems may be built by combining the simpler serial and parallel reliability models.

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