基于组织的分布式开放系统自适应机制

Self-Adaptive Mechanism in Open Distributed Systems Based on Organization Metaphor

随着分布式开放系统的涌现,其呈现出系统环境的动态性和开放性、系统成员的自主性和异构性、系统自身的分布性和层次性以及明显的社会组织特征,给自适应技术带来了新的挑战,需要跨跃成员层面(单个系统)在组织层面(系统之间)进行发散式自适应调整以及与之对应的软件抽象.然而,现阶段大多自适应技术针对单个系统采用对象范型和集中控制的方式.因此文中借鉴社会学、组织学思想,采用组织范型对系统组织层面进行抽象,提出了系统的组织元模型,使得基于组织的抽象范型与系统的组织层面相对应,缩减了问题空间与解空间的鸿沟,提出了支持组织自适应的动态重组机制,使得组织成为具有自适应能力的一阶实体,从而实现系统组织层面发散式的自适应.分别利用上下文(Context)和策略(Strategy)对组织的监控逻辑和自适应逻辑规约,通过把上下文、策略同组织显式地分离,提高了系统的模块性和可维护性.最后通过案例分析验证了文中提出的组织元模型和动态重组机制的有效性.

With the emergence and popularization of open distributed software system, it shows some new characteristics, such as the heterogeneity and openness of the environment, the auton- omy and heterogeneity of system members, the distribution and hierarchical of the system itself as well as having the characteristics of social organization. So, it brings about new challenges to self-adaptive software, which needs decentralized adaptation across the member level （a single system） to the organization level （the relation between systems） as well as the corresponding software abstract paradigm. Most of the current work, however, has focused on a single system using the object paradigm and centralized control. Therefore, inspired by social organization idea, we address this challenge by using the organization paradigm to abstract the organization level of the system and proposing an organization metamodel, so as to reduce the gap between the problem space and the solution space. A dynamic reorganization mechanism for supporting self-adaptive organization is put forward, so making the organization as a first class entity with self-adaptivity, by which decentralized adaptation at the organization level is implemented. The organization＇s monitor logic and adaptation logic are specified by context and strategy separately. By means of separating explicitly the context, strategy and the organization, the system＇s modularity and maintainability are improved a lot. Last, the effectiveness of the organization metamodel and the dynamic reorganization mechanism is verified by a case study.