5.6 The Spectrum of Support for Locating Information

As epitomized in the problem of locating reusable components analyzed in Chapters 3 and 4, a wide gap exists between the user needing information and the information system providing information. Three approaches exist to bridge this gap as shown in Figure 5.5.

Figure 5.5: The spectrum of support to information location

$\parbox{.8\linewidth}{\small{The first part of the figure describes ... ...the role of expert and locates the information using a pure access mechanism.}}$

The first approach is taken by passive information systems based on pure information access mechanisms. For users to acquire the needed information, they must bridge the gap by themselves after they have learned how to use the system, how to write appropriate queries, and to anticipate the existence of information. This approach can be called the user-expert approach because the user is trained to be an expert in using the system.

The second approach is the computer-expert approach, in which the computer system plays the role of expert and tries to infer the needs of users and deliver the precisely relevant information. Although this approach is ideal, due to the incompleteness of task models, it is very difficult to implement such smart systems.

The third approach is the distributed-expert, or the human-computer cooperation approach. It acknowledges the fact that neither computers nor users have enough expertise to find the relevant information alone, and the expertise is distributed among users and systems--users know their needs, and systems know what exists in their repositories. To overcome this symmetry of ignorance or asymmetry of knowledge [Rittel, 1984], cooperation is needed between users and computer systems. Active information systems incorporated with the retrieval-by-reformulation mechanism adopt such an approach. Their delivery mechanism first presents a set of potentially relevant items of information based on inferred task models, discourse models, and user models, and then users contribute to the process of information location through the retrieval-by-reformulation mechanism. This cooperation process is also a mutual learning process. From the users' reformulation process, systems learn the knowledge level of users and the larger context of their tasks to augment the discourse model and user model that can make systems deliver more context-relevant information later. From the deliveries of systems, users learn the structure of information systems and the availability of relevant information, which can be utilized in their later retrieval activities.