Heuristic-DENDRAL

Computer-aided structure elucidation (CASE) has been developed over a period of 30 years. Several major projects that were initiated and carried out during this time consist, in the main, of interdisciplinary efforts toward the automatic solution of problems arising from the everyday practice of chemists. The DARC system of Dubois et the Heuristic DENDRAL project developed at Stanford University, and the CHEMICS system of Sasaki et as well as the developments of... 

DENDRAL consists basically of two subprograms Heuristic DENDRAL and Meta-DENDRAL. Heuristic DENDRAL uses the mass spectrum and other available experimental data to produce a set of potential structure candidates. Meta-DENDRAL is a knowledge acquisition system that receives the structure candidates and corresponding mass spectra to propose hypotheses for explaining the correlation between them. These hypotheses are validated in Heuristic DENDRAL. 

One of the most successful approaches to structure identification by means of computers was achieved at Stanford University with the Heuristic Dendral Program, based on the dendritic algorithm of Lederberg The Heuristic Dendral Program (HDP), as it was before 1970, is explained in various publications 40-42i and summarized in Fig. 1. The data, a mass... 

Two of the first AI programs in chemistry were DEND-RAL and OCSS." The DENDRAL project can actually be broken into two separate subprojects, as shown in Figure 3. The first is heuristic-DENDRAL, which was a rule-based program whose purpose was to elucidate the possible structures for a molecule based on the mass spectrum. The second is Meta-DENDRAL, which was a learning program that accepted structure-spectrum pairs and attempted to create rules that would be usable by heuristic-DENDRAL. 

DENDRAL followed a three-stage procedure. In the first phase, the so-called plan, prior knowledge, and heuristics were used to deduce a set of constraints. Constraints could be, for example, the exemption of large sets of candidate solutions or the suggestion for a extensive search over limited classes of solutions. 

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