A Facility Framework for Distributed Application

The domain of distributed applications is developing rapidly. Facilities to support distributed applications have till now been designed on a case by case basis for each specialized user application. A systematic study and a generic facility framework for executing distributed applications are currently nonexistent and progress towards their development would have a significant impact in the seamless use of distributed applications. In line with these objectives, we have developed a component-based facility framework for distributed applications. The facility is defined as a high level conceptual facility which serves as an infrastructure providing services for distributed applications. The conceptual facility includes hardware and software (e.g. sensors, actuators and controllers) as sub-layers, which are dispersed physically. In this paper, we describe the framework, and examples are used to illustrate potential implementations of important concepts. The workflow of a distributed application is also provided. An implementation of a distributed application, with a partial version of the designed facility framework, for the water level control system of a nuclear power plant steam generator is used for evaluation of the concepts. Results convince us that the implementation as well as the facility is feasible. Application performance is shown to be affected by the time delay of data transmission and reasons for such delay are examined. A network quality test provides statistical estimates of data transmission delays due to the network. The results demonstrate that network quality is not a bottleneck for implementation for implementation of the component-based distributed application and support the hypothesis that a feasible implementation of such a conceptual facility framework is possible.