Research On Software Self-adaptive Based On Dynamic Software Architecture

With the development of computer technology, software systems become more and more sophisticated. In order to adapt to the dynamic and open network, integrate heterogeneous hardware resources and satisfy changing needs of users, software system requires the capability of perceiving changes in the own states and environment on runtime, implementing static adjustment and dynamic evolution according to the goal of functionality, no-functionality, providing high quality and sustainable service. Software system has this ability also called adaptive software. An adaptive cycle contains three phase, including perception, decision-making and execution, which demand data integration between environment space and target system, intelligent decision-making and dynamic evolution respectively.Software architecture describes the system architecture in a global perspective, providing integrity and availability of all the adaptive phase. While a number of key issues need to be addressed:How to describe the dynamic nature of software architecture exactly; software requires a system capable of autonomous adaptive perception, decision-making and evolution. Decision-making process in now most adaptive systems is relatively simple, some more intelligent approaches should be provided to decision making.Combined with the existing software architecture researches, this article gives a software framework based on an adaptive component system, the framework including user layer, control layer and the target layer. We also discuss the mechanisms and algorithms in the perception, decision-making and execution phase:(1) Analysis the dynamic of software architecture based on the existing software architecture researches, aims to provide a theoretical foundation for the dynamic evolution of the architecture.(2) when system making decision, firstly, from the perspective of meeting multiple quality attributes objective of software system, this article provides a decision-making method, which calculate comprehensive quality attribute utility value of every action that suits to the environment, based on decision-utility theory, secondly, consider the number and priority of components that affected by adjusted action. The best tactic selected by the results of the mentioned factors.(3) The design of a suitable software architecture model on dynamic configuration, including meta-level, configuration layer and base-level, the meta-level maintains architecture information. The dynamic configuration of system through adjusting architecture meta-level, trigger and implement the adjustment of base level.Finally, a news website system case used to verify the feasibility and effectiveness of the key technologies proposed in this paper.