Building Practical Software Quality Models

软件总拥有成本（TCO）包括获取和保持程序运行的所有成本，从规范到许可再到培训。维护占TCO的50%到70%。它包括修改程序以修复旧功能和添加新功能的成本。公司需要评估和改进其程序可维护性以降低TCO的方法。ISO9126指出，在更改/维护程序时，有四个因素会影响开发人员：其可分析性、可变性、稳定性和可测试性；这就形成了可维护性的质量特征，并导致了两个主要问题。Prb1：开发人员和他们的团队领导必须评估程序的可维护性，以决定是否值得更改程序。Prb2：开发人员需要帮助来识别不同的可选变更集，这些变更集将提高他们的程序可维护性。（经验）软件工程领域现在提供了丰富的事实和数据来构建程序的可维护性评估模型。然而，以前的工作没有把所有这些放在一起来产生实际的可维护性评估模型。此外，除了评估可维护性之外，开发人员还必须在修复/实现功能之前识别和权衡必要的更改，以提高程序的可维护性。它们需要实用的可维护性改进模型，提供不同的可选变更集。我的目标是建立一个推荐系统，基于实用的可维护性评估和改进模型，量化和提高可维护性，帮助面临Prb1和Prb2的开发人员。我将使用系统的文献综述来理解程序的可维护性和转换。收集程序及其可维护性的相关数据，特别是专家意见，建立样本数据库，用于培训质量评估和改进模型。我将对模型进行实证评估，并开发研究原型来收集程序数据，评估其可维护性，并使用模型提供改进建议。由此产生的推荐系统将帮助开发人员和团队领导降低可维护性成本，从而降低他们的程序TCO。

A software total cost of ownership (TCO) includes all the costs to acquire and keep a program running, from specifications to licenses to training. Maintenance contributes between 50% and 70% of TCO. It includes the costs to change the program to fix an old feature and add new features. Companies need means to assess and improve their program maintainability to reduce their TCO. ISO9126 states that four factors impact developers when changing/maintaining a program: its analysability, changeability, stability, and testability; which form the quality characteristic of maintainability and lead to two main problems. Prb1: developers and their team leaders must assess program maintainability to decide whether it is worth changing the program. Prb2: developers need help in identifying different alternative sets of changes that would improve their program maintainability. The field of (empirical) software engineering now provides a wealth of facts and data to build maintainability assessment models for programs. Yet, no previous work put all these together to produce practical maintainability assessment models. Also, beyond assessing maintainability, developers must also identify and weigh changes necessary to improve their program maintainability before fixing/implementing features. They need practical maintainability improvement models providing different alternative sets of changes. My goal is to build a recommender system, based on practical maintainability assessment and improvement models, to quantify and increase maintainability and help developers facing Prb1 and Prb2. I will use systematic literature reviews to understand program maintainability and transformations. I will collect programs and related data pertaining to their maintainability, in particular experts' opinions, and build a database of samples with which to train quality assessment and improvements models. I will evaluate the models empirically and will develop research prototypes to collect data on programs, evaluate their maintainability, and provide suggestions of improvements using the models. The resulting recommander system will help developers and team leaders reduce maintainability costs and, thus, their program TCO.