Research On Key Technology Of Self Adaptive Software

Modern software technology must face three challenges:1. With the development of computer hardware, software and network technology, moreand more powerful hardware systems appear.2. With the popularity of the Internet, the software system built on the Internet has alsobecome a trend. The environment of Internet is complex and changing, so the system on it mustadapt to this change.3. With the improvement of the quality of the software’s users and the expansion of thecompany’s business, new requirements is coming. The software must adapt these newrequirements as soon as possible.To deal with these challenges, it has to return to the software design phase and redesign thesoftware according to new environment and requirements. But, there are some troubles. First,the developers and user of the software are usually belonging to the same institution. When thesystem needs redesign, the institution may no longer exist, or can not be implemented becauseof funding problems. Second, the new technology does not completely guarantee compatibilityof old technology. Last, for some software if you stop them to run the upgrade, the costs aresignificant.If the software can consider the future possible change in its design phase and can selfreconfigure according to the environmental changes and customer needs, then the software lifecycle will be longer, and greatly reduce the cost of maintenance in the runtime. This approach issoftware self adaptive technology.In the dissertation, we do some research on several key technologies on the basis ofexisting work in the area of self adaptive software.Firstly, the dissertation analyzes adaptive software technology in-depth, including theorigin of adaptive software, range of applications, the basic architecture, implementation style,etc. Then we study self adaptive software’s context aware, software service quality modeling,self adaptive software’s reconfiguration, and self adaptive software’s Creditability. These arekey issues of self adaptive software. We have proposed solutions to these issues. Specifically,the research works mainly include the following aspects:1. Research of Adaptive software infrastructure. We introduce current status of selfadaptive software, analyze basic principles of adaptive software, and propose basic architectureand implementation style of adaptive software. The research gives some guiding principles forbuiding adaptive software from a macro perspective and lays the foundation for further study ofadaptive software. 2. Research of Adaptive software’s context aware. The reconfiguration of self adaptivesofware is usually caused by change of its running context. So, how to design a good frameworkfor context-aware, is a very important research direction.3．Research of software service quality modeling. In this dissertation, using domainanalysis technology and two level modeling technology, we propse a formal description of thecomponent’s QoS metamodel and define a domain-specific QoS modeling language. Thislanguage can be used to define domain specific QoS information.4. Research of self adaptive software reconfiguration. Reconfiguration is core of selfadaptive software. In the dissertation, we study the design time reconfiguration and the runtimereconfiguration. Runtime reconfiguration must have external forces to implement in accordancewith the particular system blueprints. This particular system blueprint is the softwarearchitecture. Starting from the composition of the software architecture, style, and description,we study the general principles and basic guidelines of the software architecture. In order tosupport the runtime reconfiguration, we propose a reconfiguration method based on softwarearchitecture.5. Self adaptive software’s Creditability. Only guarantee adaptive software at runtimereconfiguration is not enough, it must also ensure that the self adaptive software is still able tocorrectly provide services after reconfiguration. This is the research work of credibility. In thedissertation, we propose the formal definition of the credibility from the different sides,including the integrity of the replacement, consistency of the interface, consistency of state,consistency of the system constraints.Innovation of this dissertation is:1．Propose a context aware framework. In this dissertation we formalize the contextinformation and context information mapping, and describe the process of modeling of contextinformation’s collection. Then, on the basis of the existing research we propose a improvedcontext aware framework.2. Propose a QoS modeling mechanism using in component-based self adaptive software.Using domain analysis technology and two level modeling technology, we propse a formaldescription of the component’s QoS metamodel and define a domain-specific QoS modelinglanguage. This language can be used to define domain specific QoS information, can havedifferent syntax manifestations and unified semantic base. So, models can be delivered andtransfered easily between different areas or different system. Becausethe entire QoS meta-modelis based on the MOF, that is MOF can also describe QoS metamodel. So QoS models defined byit and other MOF-based modeling languages have the basis of a unified semantic.3. Research on the key issue in the reconfiguration of the architecture. In the research of software architecture, we analyze six kinds of architecture styles and study the possibility ofsupporting dynamic reconfiguration. Also, we propose three modes of self adaptive software:object management reconfiguration, component replace reconfiguration and restructuringreconfiguration. We believe that reconfiguration of self adaptive software is not only relatedwith software architecture, and associated software application framework. Different applicationframework causes different reconfiguration way. Most of the literature in the study of theso-called reconfiguration or evolution believe all reconfigurations are that growth, delete,change of components and connectors. They ignore obviously the role of application frameworkin reconfiguration.4. Introduce creditability into reconfiguration of self adaptive software. About thecredibility of the software has been extended from the design phase to the run phase. Thisdissertation analyzes the credibility issues that may arise in the process of self adaptive softwarereconfiguration, and the use of the the CSP technical means and research tools to achievecredibility formal description or algorithm. This ensures that the adaptive after the software stillis to meet user expectations.