Whether it is the classic software process model, or a variety of other agile methods pipeline theory, are organized by software process model of software development, software development process model emphasis on process management, this section we process through the elements view to analyze the software development process. Any form of software development process can use the processes, people and technology to cut into three aspects. Define a series of steps to develop the process and method of operation, need to upgrade their skills through training and management, and technology in the broad sense, including applications, tools, languages, information and the environment.
Industry on how to improve the process and there are some methodological framework, the most representative is CMMI (Capability Maturity Model Integration, Software Capability Maturity Model Integration). The agile method also provides a number of practices, processes and tools specifically for process improvement. This paper briefly describes the CMMI process improvement.
1. CMMI fundamental concepts
CMMI consists of a set of process areas (Process Area), some goals (Goal) and a number of engineering practice (Practice) composition (see below). Five levels are formed by combination of those elements, respectively, from low to high is called an initial stage (Initial), Repeatable (Repeatable), defined level (the Defined), quantitative management level (Managed) level and continuous optimization (Optimizing ).
The initial stage of the process is not institutionalized, the process is disorderly and even chaotic, almost no well-defined process through the implementation process difficult to predict. In the initial class organizations generally do not have a stable development environment, the success of the project depends on the efforts of individuals or groups, depending on the elite and personal experience (see figure a). Established in the project Basic project management processes to track cost, schedule, and functional properties, to develop the necessary process discipline, can repeat the success of previous similar projects acquired with these characteristics is repeatable level (see Figure b). Defined level, the process in terms of both management and engineering have been documented and standardized, and formed a tissue level of process assets. All projects use approved by standards and tailoring the process to develop and maintain, need to collect data, but also use the data (see Figure c). The quantitative management level using statistical and other quantitative techniques of project control process, the establishment of quantified targets for quality and process performance as a criterion process management, quality and process performance metrics data can be used to support decision-making (see below d) . The final stage continuous optimization process based on quantitative performance reasons deviation analysis, continuous process performance improvement by progressive technical improvements and innovations. Process improvement organization be identified, evaluated and implemented, and the staff involved in the optimization process (see FIG e).
CMMI concerned about people, tools and methods, from the initial stage of the disorder began, the establishment of project records, to establish stable and consistent process, based on facts and be able to achieve continuous innovation and improvement of continuous optimization level, the company's maturity process is divided into five grade. We will institutionalize standards development process is key to implementing the CMMI process improvement.
2. CMMI process improvement in the core domain
CMMI process areas to divide all into four types, namely the construction process closely related to management, project management, engineering and support, process management and system development process discussed in this chapter. To CMMI Dev 1.3, for example, related to the process management process areas, a total of five, including:
- Organization-level process definition (Organizational Process Definition, OPD), to establish and maintain useful organizational process assets
- Organizational level Process Focus (Organizational Process Focus, OPF): plan and implement organizational process improvement based on understanding the strengths and weaknesses of existing processes on
- Organization Training Management (Organizational Training, OT): increase the skills and knowledge at all levels of the organization, so that they can effectively perform their tasks
- 组织过程性能（Organizational Process Preformace，OPP）：建立与维护组织过程性能的量化标准，以便使用量化方式的管理项目
- 组织性能管理（Organizational Performance Management，OPM）：用量化的目标来驱动，并且用量化的方式来监控改进的效果
CMMI又根据目标等级的不同把这五大过程管理类过程域分成基本过程管理类过程域和高级过程管理类过程域两大类。项目两张图描述了这两类过程管理类过程域与其它过程域类别之间的互动关系。关于CMMI的详细讨论不是本书的重点，更多内容可参考相关资料。
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