A software tool for structured modeling and monitoring of dynamic systems
Patricia A. Wenner · 1990
Dynamic data characterizes many systems in manufacturing and business. A supervisor tracks the progress of the system by checking on the changing values of parameters describing the system, but incidents like Three Mile Island make it clear that a human being can be overwhelmed by data. Computers can be used to organize data as information. This research is in the area of computer interfaces to such systems. A literature search of research in the theory and application of monitoring in computer science was done. Current monitoring systems for dynamic data environments were evaluated. An analysis of various dynamic data environments was performed to develop requirements for effective monitoring. A monitoring environment is defined which includes an English-like language, Graphical Monitoring Language (GML), based on the concept of the abstract data type. This language permit modeling of the system by defining system data types which are then used to construct the model. Monitor data types are provided as the building blocks of the monitor. These types are defined by the monitor designer in the vocabulary of the domain. Access to GML is provided through an interactive environment. To show the feasibility of the design, a prototype monitoring environment was developed in Smalltalk. A browser-like interface is provided for definition of the model and the monitor. Pull-down menus provide the designer with semantic constructs, the system and monitor data types. Interactive editors, such as display layout, are offered when appropriate. The runtime environment executes the monitor which has been defined. It includes a display maintainer, an event tracker, an alarm tracker, a milestone and suspense tracker, and a timefile interface. Exercise of the designed monitors is provided, with the discrete event simulation objects available in Smalltalk. The environment was used to develop monitors for several example systems. The usability of the system by a typical user was demonstrated for both reading a monitor description and for developing a monitor. A case study of the use of the system to model and monitor a long-term-care facility was conducted. The environment provides for modeling and monitoring at a level much higher than available from current monitors.