TYPES OF USER INTERFACE
In this section, several different kinds of user interfaces are described, including naturallanguage
interfaces, question-and-answer interfaces, menus, form-fill interfaces, commandlanguage
interfaces, graphical user interfaces (GUIs), and a variety of Web interfaces for use
on the Internet. The user interface has two main components: presentation language, which
is the computer-to-human part of the transaction, and action language, which characterizes
the human-to-computer portion. Together, both concepts cover the form and content of the
term user interface.
Natural-Language Interfaces
Natural-language interfaces are perhaps the dream and ideal of inexperienced users, because they
permit them to interact with the computer in their everyday, or natural, language. No special skills
are required of the user, who interfaces with the computer using natural language.
The display depicted in Figure 14.9 lists three natural-language questions from three different
applications. Notice that interaction with each seems very easy.
For instance, the first sentence
seems
straightforward: “List all of the salespeople who met their quotas this month.”
The subtleties and irregularities residing in the ambiguities of English produce an extremely
exacting and complex programming problem. Attempts at natural-language interfacing for particular
applications in which any other type of interface is infeasible (say,
in the case of a user
who
is disabled) are meeting with some success; however,
these interfaces are typically expensive.
Implementation problems and extraordinary demand on computing resources have so far
kept
natural-language interfaces to a minimum. The
demand exists, though, and many programmers
and researchers are working diligently on such interfaces. It is a growth area, and it therefore
merits continued monitoring.