The Research And Design On Mechanism Of Specifying And Sensing The Environment Of Self-adaptive Agents

With the popularity of Internet,the runtime platform of software system changes from static,obturated,controllable unique-computer environment to dynamic, opened, difficult-controlled net environment. The openness of Internet causes software which runs in the Internet environment possessing the fuction that traditional unique-computer's software does not have. However, it is diffcult for traditional software-models and software developing patterns to adapt to developing and running softwares in the Internet environment. For this reason, we need to propose new technique to support developing softwares in the Internet environment. In this contidion, the introduce of the concept of Self-adaptive software provides an effective thought for software models and software developing patterns in the Internet environment.An important characteristic of Self-adaptive software is that software entities can sense the change of external environment, and excute corresponding Self-adatpive behaviours according to that change. In this process, sensing the environment is the foundation of Self-adaptive software adaption to the change of environment, and the definition as well as the explicit description for Self-adaptive software's environment is the precontidition to implement adaptive behaviours. Therefore, how to define and explicitly describe the Self-adatpive software's environment, as well as how to sense the environment for Self-adatpive software entities is an important subject for current researches on Self-adaptive software.This article investigates on the environment of Self-adaptive software based on Agent . The investigation includes three aspects.(1) The composing of the environment, that is the changes about the amount and the type of enrionment-elements. This article defines the environment of Self-adaptive Agent as an aggregate of some Agents or Self-adatpvie Agents that the Self-adaptive Agent concerns with. According to the aspects with which the environment concerns, the article classfies the environment to four types: Topic, Service, Agent and Role. The article also describes the environment explicitly with a traid.(2) The way in which environment transforms, that is about whether environment-elements is changed, as well as the content of the change. This article uses environment-messages to describe the content of enrioment-element's change. When environment-element changes, an environment message contain the content of the change will be produced. (3) The way in which the environment is sensed, that is about how Self-adaptive Agent senses the change of the environment and the content of the change. This article designs Publisher/Subscriber for Self-adaptive Agent to publish/subscriber environment message, the article also designs for receiving environment message. Publisher can be used by Agent/Self-adaptive Agent to publish environment message.Self-adaptive Agent senses the change of environment by receiving environment message subscribed by itself.(4) A case is developed to validate our method.These efforts solves the problem of how the environment drives Self-adaptive Agent's self-adaptive behaviour, which are benefit to promote the Agent-Orient technique's application in the development of Self-adaptive software.