ABSTRACT
This chapter focuses on users and the user interface with knowledge-based systems. For users to make effective use of an information system, they must have a cognitive framework, or mental model upon which to hang their understanding. Search processes in electronic information systems are constrained by interface design. Retrospective searches are undertaken when a user wishes to become informed of knowledge on a specific topic. The idea of direct manipulation is that the user's actions should directly affect what happens on the screen, in the sense that there is a feeling of physically manipulating objects on the screen. Web screens look a little different from Windows graphical user interface (GUI) screens, since they are written in Hypertext Markup Language. GUIs use a combination of direct manipulation, windows, dialog boxes, menus, buttons and check boxes, icons, form filling, question and answer and command languages. Voice-based dialogues and multimedia interfeces are also important in some applications.
