Designing and Implementing Adaptive Distributed Systems

自适应计算系统是一种基于环境变化来进化其行为的系统。对于建立在分布式体系结构上的可适应系统，其中多台机器通过网络连接，这种变化可以从站点故障到更新的应用程序需求。当发生变化时采取的演进动作也可以变化，范围从动态地重新配置系统软件以在变化的条件下保持相同的服务保证，到与应用协商新的服务保证。 这个项目的目标是为设计和实现自适应分布式计算系统开发基本的新技术。 具体的重点是提供一个分布支持层，一个软件层实现强大的执行保证有关的分布式状态的应用程序，可以适应变化。该研究集中在两个调查线：（1）这种类型的系统的概念模型的发展和（2）一种新的方法来实现自适应分布式系统的基础上细粒度的代码模块称为微协议。该框架正在扩展，以支持软件的动态演化，包括重新配置，动态代码链接和运行时代码生成。 ***

An adaptive computing system is one that evolves its behavior based on changes in the environment. For an adaptable system built on a distributed architecture where multiple machines are connected by a nework, such changes can range from site failures to updated application requirements. The evolutionary action taken when a change occurs can vary as well, ranging from dynamically reconfiguring the system software to maintain the same service guarantees under changed conditions, to negotiating new service guarantees with the application. The goal of this project is to develop fundamental new techniques for designing and implementing adaptive distributed computing systems. The specific focus is on providing a distribution support layer, a software layer implementing strong execution guarantees regarding the distributed state of the application, that can adapt to changes. The research concentrates on two lines of investigation: (1) the development of a conceptual model for systems of this type and (2) a new approach to implementing adaptive distributed systems based on fine-grain code modules called micro-protocols. The framework is being extended to support dynamic evolution of software, including reconfiguration, dynamic code linking, and runtime code generation. ***