Focus pert system for LC methods develop ment, Wade has been using the Teknowledge M.l expert system de velopment shell to encode the exper tise of chromatographer V. L. McGuffin as a set of rules and facts. An ex pert system development shell is a commercial program that provides the structure for development of an expert system. "We have a program that works," says Wade. "It gives us a number of options for sample pretreatment, mode of separation, and type of col umn packing, and solvent selection ca pability is currently being implement ed. The results are usually correct— that is, the selection our expert would make. But the system is still small and needs a lot more development. At present it contains about 150 rules and about 150 other knowledge en tries." The MSU system is primarily edu cational in nature, and commercializa tion is not anticipated. According to Wade, "If students can ask 'Why?' at any time, then obviously they will learn more from an interactive envi ronment rather than if they just sat and listened to a lecture or read a book on chromatography."
ttThe question for those who make expert systems may not be, 'How does an expert solve the problem?' but 'How should an expert go about solving the problem using all the tools available to him?'*> Troubleshooting Another approach to expert systems is represented by HPLC Doctor ($130) from Pi Technologies. HPLC Doctor is an expert system developed by Ben Buglio of Hoffman-La Roche that is directed not at methods development, but at instrumental troubleshooting. According to Tom Jupille, the pro gram operates in an interactive fash ion: "Do you have spikes in your base line? Yes. OK, shut off the pumps. Are the spikes still there? Yes or no? The same sort of thing that shows up in
troubleshooting books and service manuals. It's like having a very experi enced LC jockey sitting in the next lab who you can go to and say, 'Hey, there's a problem here.' " Jupille says that Pi Technologies will eventually offer a broad range of expert systems. "We're interested in doing programs on post-column reac tion detector optimization, GC sta tionary phase selection, and solidphase extraction techniques. All of these will be done in conjunction with outside authors." Another program available from Pi Technologies at this point is Generic Expert, which, at $80, is one of the more inexpensive expert system development shells. Fuzzy sets Stan Deming's approach to expert systems has involved the use of fuzzy sets. "Most expert systems deal with very rigid logic—a lot of if, then, else rules," Deming explains. "But many times it's hard to put analytical ques tions and answers in that kind of con text. Our approach to expert systems is to work with fuzzy sets that are based on desirabilities. The answer you eventually get might say that the desirability of a certain goal is 0.83 on
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1194 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 12, OCTOBER 1986
