Visualization and Manipulation of Structured Information

In modern object oriented visual information systems the internal state of the entire system consists of the internal states of many objects in diierent services, probably distributed over a heterogeneous network of computers. Man machine interaction in such an application is based on the visualization of states on one hand and the modiication of states on the other hand. A solution for this problem is the invention of symbols as a graphical representation of structured information, held by objects. The symbols are handled by a man machine service, which is constructed as a server. 1 Overview The main task of any man machine service (MMS) is to inform a human user of a system's state and to enable modiications of this state. Due to the fact that man can perceive and handle information fastest in a visual way, this is the best channel to inform about complex system states. The optical channel is also a good choice to support human interaction. This is achieved in feeding back the user's actions. A MMS has to provide two services: the visualization of structured information and the supported modiication of structured information Based upon these services any communication between user and machine can be realized. This paper presents the concept and an implementation of a man machine service, usable as a server in a heterogeneous network of computers. 2 Symbols A symbol is a graphical representation of a structured data type 2]. The user can deene symbols very exible with a tool called Symboleditor. The deened symbols are stored in a connguration database for usage within the application. Symbols can be deened hierarchically, i.e. a symbol can contain other symbols or base symbols. Changing a value of a data type connected to a symbol leads to a diierent graphical representation. Changing the graphical representation (e.g. the user moves a symbol interactive) leads to a diierent data type value. The relations between data type values and the resulting images can be deened. This relation is either continuous, where we provide linear or logarithmic functions, or discrete. Common attributes to symbols and base symbols which can be modiied are: The position speciies the location of a symbol or a part of it.