Papers in PDF format

esponse. It may be a bibliographic citation or a name of expert. Each of the above mentioned objects has its
own index which labels the object and can be used for retrieval.
There are two basic approaches to finding information in a CBAS: searching and browsing. In
searching, a user specifies what he/she is interested in finding by specifying some physical or functional parts
of a system (for example, work area and lighting) and an issue or set of issues (for example, natural light). In
response, the system finds cases or stories, that address the specified issues (in this case, a story about vaulted
ceiling and clerestory windows in the Roswell library). To make a story fully understandable, the system
presents several other things as well: (1) the generic problem the story is about (bringing in natural light),
(2) the type of solution it implements (for example, using atriums and indirect light shafts), and the larger case
the story is part of (the Roswell library design). In browsing, a user can follow links within the case library to
look at a series of stories, problems, solutions, and cases. Linkages within the system allow easy traversal from
stories to other stories that illustrate the same problem or solution; from stories to other stories from the same
larger case; and from problem to their alternative solutions. Combining the searching and browsing modes the
user can explore the cases, stories, problems and responses which are relevant to his/her goals to acquire past
experiences, learn the lessons taught, and adapt the past decisions to his/her new problem.
Implementation
Having started the development of a tool for creating and browsing CBASs we had the strong feeling that a
CBAS can be considered to some extend as an aggregate of a database and a hypermedia system. In fact, a
CBAS, on the one hand, is a special kind of database based on the cognitive theories of memory, but, on the
other hand, it is similar to a hypermedia system because it heavily uses associative links. Besides that we tried
to meet some other requirements such as: (1) the tool should work in both off-line and on-line (WWW) modes;
(2) the off-line mode should be supported on both platforms: Macintosh and IBM PC, which are popular in
academic environments; (3) the user interface should look similar in both the off-line and on-line modes.
The above intuition and requirements led us to use a multi-platform database management system
(DBMS) with a flexible scripting language for implementing the off-line version of the tool, and to use HTML
and Common Gate Interface (CGI) programs for implementing the WWW version. This decision allowed us to
meet the requirements but also brought many other advantages: first, we could borrow effective searching
techniques implemented in modern DBMSs; second, we did not have to reimplement security features for the
CBAS tool; third, the scripting language could allowed for the easy creation of user interface. FileMaker Pro
has been chosen as a multi-platform DBMS to implement the first off-line version of the CBAS tool. The
additional advantage of this choose is the possibility to share case libraries on a local network among users on
different platforms. We have chosen Macintosh as platform for publishing CBAS on the WWW. Currently we
have implemented the CBAS browser for the WWW. The next step is to implement an authoring tool for
creating CBAS using WWW clients. This will allow for a distributed team of experts to work on common
projects.
There are several other technical aspects: (1) to implement more sophisticated search techniques,
which gain more from the hierarchical index vocabulary structure; (2) to implement some adaptation and
evaluation techniques which will help the user to solve a new problem; (3) to improve the user interface using
the abilities of advanced WWW clients; (4) to add scaffolding that will help both the user to solve problems
and the experts to create or modify CBASs.
Additional information about ExtraMind and a sample case library SUSIE which was created for
learning sustainable technology can be found at http://mime1.marc.gatech.edu/WebCBRPage.html.
Acknowledgments
This work was supported by the EduTech Institute through a grant from Woodruff Foundation.
References
Domeshek, E.A. 1994. The Design-MUSE v2.0 User’s Manual
.
Domeshek, E.A.; Herndon M.F.; Bennett A.W. & Kolodner, J.L. 1994. A Case-Based Design Aid for Conceptual Design of
Aircraft Subsystems. In Proceedings of the Tenth Conference on AI for Application , IEEE Computer Society Press:
Washington, 63-69.