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Software structure of UIMS

The authors of [50] have identified some requirements of systems for the development of user interfaces (UIs): consideration of standards, openness to all interaction styles, and provision of comfortable design tools. They argue that most of the existing systems fulfill only some of those requirements. Therefore, they present a layered model for the interface between an application's functionality and its UI which will especially be useful for the design of UIs for multi-tasking, multi-windowing systems that support a free choice of input and output media. Two pictures shown in figure 4.3 are best suited to show their approach.

  
Figure 4.3 : The basic software architecture (left picture) and the corresponding layered model for human-computer interaction (right picture). (Adapted from [50])

By introducing these layers, the authors want to achieve ``a clear separation of application functionality from dialog functionality, and a clear responsibility for the different actions that are involved in a dialog.'', i.e. different actions are located in different layers. The responsibilities (and functionalities, resp.) have been defined as follows:

presentation layer:
output to the screen; handling of inputs from the user; toolkit functionalities
virtual presentation layer:
separation of input and output [...] from the dialog; definition of logical devices and virtual terminals; machine- and device-independent presentation; handles all static aspects of the UI
virtual application layer:
contains the semantics of the respective application; dialog between the user and the application; handles all dynamic aspects of the UI
application layer:
application's functionality

Another aspect of this implementation is the object-oriented approach which allows the layers to communicate via messages. Such a well-defined, layered model seems to be a good approach for an independent, thus flexible implementation of a human-computer interface which can also be used for a multimodal application.



next up previous contents
Next: The cognitive coprocessor Up: Architectures and Interaction Previous: Architecture of a



Esprit Project 8579/MIAMI (Schomaker et al., '95)
Thu May 18 16:00:17 MET DST 1995