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6. PROSPECTS

Though reading the future is a difficult and hazardous thing to do, the author will conclude this chapter with some reflections on the past and the future.

The past can probably best summarized by investigating how much attention the knowledge-based systems/expert systems community has paid to methodologies. To investigate this topic, the author made an analysis of two main sources of publications concerning expert systems:

  • The journal Expert Systems, founded in 1984, is an example of a journal with a definitely practical interest, which is combined with two or three "in-depth" articles in every issue. As the journal has maintained this approach as well as its layout for 13 years, it is particularly suited for a comparative analysis. The analysis covered Volumes 2 through 13 (3).
  • The Proceedings of three consecutive World Congress on Expert Systems™ Conferences held in 1991, 1994, and 1996 (Liebowitz, 1991; 1994; Lee et al., 1996). As these congresses are not "AI" congresses and are strongly focused on the practical aspects of developing KBSs, they can be seen as another major forum for dissemination of expert systems related results.

All articles and papers in these sources were analyzed8 for references to methodologies and classified the "hits" in two groups:


8Unfortunately, one could not rely on the abstracts, due to the confusion about terminology. Many papers referred to "methodologies," which in terms of the classification presented in Section 2 are techniques or methods.
  1. Papers describing the development of an (operational) expert system, that pay explicit attention to the way it was developed, most of the time referring to a life cycle approach (application papers in Tables 1 and 2).
  2. Papers mainly or wholly devoted to describing or discussing methodologies as defined in Section 2. In this category are also included papers that did not cover the complete life cycle, but only the major part of it (e.g., knowledge acquisition and design-development, full papers in Tables 1 and 2.)

Together these sources provide a base of approximately 900 papers in the area of expert systems, which probably is still a moderate sized sample of all papers ever written about this topic. However, given the practical orientation of the two sources it can be argued that this base will more or less correctly reflect the trend in the field concerning the attention paid to methodologies.

In Table 1 the results for Expert Systems can be found. As this journal has maintained its size and composition over the period studies, there is no need to compute percentages.

As can be seen from Table 1, 31 papers appeared paying attention to methodologies, equally distributed between the two categories (this is almost 20% of all papers that appeared in the period studied). The peak year is 1990 and taken together, 1990, 1991, and 1992 account for almost 50% of all methodology-oriented papers. In later years, the numbers return to their pre-1990 values. This seems to corroborate the notion that the methodology heyday's fell somewhere in the early 1990s.

Table 2 gives the results for the World Congress on Expert Systems™ proceedings. As the number of papers in the Proceedings (N) is different over the years studied, percentages are computed for comparisons.

From Table 2 it is clear that there is a drop in absolute numbers between 1991 and 1996 of papers referring to methodologies. In percentages, 1994 is the peak year. As this conference was held in January 1994, most papers must have been written in late 1992 or early 1993. This is in line with the trend in Table 1, showing a peak in the early 1990s. Again, there is a clear decline in numbers and percentage in 1996.


TABLE 1
Methodology-Related Papers in Expert Systems, 1985-1996
 
Year Application papers Full papers
1985   1   0
1986   2   0
1987   0   1
1988   1   2
1989   0   1
1990   3   4
1991   1   2
1992   3   1
1993   1   1
1994   1   2
1995   1   0
1996 (3 issues)   1   2
Total 15 16

Tentatively, the conclusion is that there seems to be a decline in interest in general methodological issues in KBS development. Expert systems are becoming increasingly absorbed in overall system development and will be subject to methodologies and life cycle approaches used for conventional information systems. Consequently, in the opinion of this author, there will be less and less room for very KBS-specific methodologies, notwithstanding the theoretical and practical merits they have. This is not to say that all efforts in this area were wasted. Given the peculiar nature of some aspects of KBS development, there will be a niche for products of the focused approach type. Also, modeling efforts and modeling languages developed in the framework of methodologies will quite likely survive their originating methodologies. The risky nature of many expert systems projects have contributed to the increasing importance of risk analysis in systems development in general and boosted risk driven approaches pioneered by Boehm in the mid-1980s.


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