Abstract: Middleware is an important method for software self-adaptation， which should provide not only the general built-in self-adaptation mechanisms， but also the development and runtime supports for application of specific ones. This paper addresses the self-adaptation problem in ubiquitous computing software by using the principal of separation of concerns and introducing policies to model the software self-adaptation processes. The policy-based software self-adaptation concept model and the adaptation-enabled， base-meta level divided light weight component model are proposed， based on which a policy-based software self-adaptation framework is designed and implemented on a ubiquitous self-adaptation middleware named UbiStar. The framework provides the development and runtime supports for ubiquitous applications compliant to above models， and thus enables effectively for application-specific software self-adaptation processes.

Key words: ubiquitous computing, middleware, self-adaptation, policy, component, computing reflection

摘要： 中间件是支持和实现软件自适应的重要手段。除了内建于中间件的通用自适应机制外，中间件还应当为应用相关的自适应过程提供开发和运行支持。以普适计算为背景，基于关注点分离原则，引入策略对软件自适应过程进行抽象描述，提出了基于策略的软件自适应概念模型，进而提出了适应使能、基层和元层分离的轻量级构件化实现模型。基于上述模型，在面向普适计算的自适应中间件平台UbiStar中设计实现了一种基于策略的软件自适应框架，可以支持基于上述模型的普适计算应用的开发和运行，从而为应用相关的软件自适应过程提供有效支持。

关键词: 普适计算, 中间件, 自适应, 策略, 构件, 计算反射