Information Technology Reference
In-Depth Information
1.6
Human Computer Interaction
An essential aspect of the design of any information system is the specifi-
cation of the interfaces the system offers to the people that will interact with
it, something that is normally called human-computer interaction. In this
design field, the user interface (or UI for short) is where interactions between
humans and machines occur.
A typical enterprise design will be concerned with many kinds of activity.
Some of these will involve people, some will involve automated solutions, and
some will involve human-computer interaction. However, these categories are
not fixed; there will be a progressive migration towards automated solutions,
without there necessarily being major structural changes in the design.
While, in a suciently abstract description, the functions performed can
remain the same when such changes are made, the disciplines involved in
expressing their detail are quite different; middleware providers and user in-
terface designers use different tools and techniques. However, both disciplines
make heavy use of tools. In the middleware world, tools automate generation
of stubs from interface definitions and handle the incorporation of mechanisms
to ensure reliability and fault tolerance. Tools applied to the user interface
design, on the other hand, can produce software components to act as user
proxies within the system and manage user dialogues in terms of interaction
with, for example, a sequence of web forms and other pages. These tools can
also be used to apply a uniform look and feel across the organization.
In the descriptions that follow, we will focus primarily on system structure,
but we will indicate how the approach also enables the management of human-
computer interaction, using either the same information that captures the
system structure or specific information added to support this aspect of the
design.
Thus, the enterprise description can be used to identify interactions be-
tween human and system-supported activities, while the information view-
point can define data types that can be used either in system-to-system in-
teractions or in user interfaces and the computational viewpoint can contain
details of the dialogue needed to support human-computer interaction.
Introducing the support of user interfaces into the design will, in general,
result in the inclusion of distinct objects into the computational design to
represent each user and the proxies for these users within the supporting
system. Doing so adds precision to the specification of the user interactions
expected and, as we shall see in chapter 8, provides a basis for testing the
correctness of conformance to the user interactions specified.
The support for user interaction is thus incorporated within the viewpoint
framework, but we shall return to this topic to bring out the consequences for
the individual viewpoint languages as they are discussed in following chapters.
