HEPHESTUS: An expert system in PROLOG for the interpretation of pyrolysis mass spectra of polyesters, polyethers and polyureas
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Kontoyannakos, J
(EN)
Georgakopoulos, CG
(EN)
Statheropoulos, M
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Parissakis, G
(EN)
The construction of an expert system (ES), called HEPHESTUS, was implemented in a PROLOG environment, for the interpretation of pyrolysis mass spectra (PyMS) of three categories of polymers: polyesters, polyethers and polyureas. The ES can be applied in electron ionization, chemical ionization and desorption chemical ionization PyMS spectra. The knowledge of the domain is organized in the form of rules that relate polymer structures with mass spectra characteristics. This methodology uses mainly the following type of information: presence of repeating units, cyclic oligomers, mass markers, mass fragments and various mass series. The IF part of the rules tests for matching the information extracted from the unknown PyMS spectra with those of the knowledge base. The knowledge base is organized as dendrite, i.e. the polymer structures are organized hierarchically as a tree. Examples of the interpretation rules used are described together with examples of searching and reasoning. The system was evaluated for both spectra that belong to the above three categories and for other spectra. The ability of the system to interpret PyMS spectra of the three categories of polymers is demonstrated and discussed.
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