Abstract: An inference system comprising: a knowledge base defined as a set of rules described for a multiplicity of inference objects of one kind; a working memory storage unit including a region for temporarily storing an intermediate hypothesis to be modified and executed based on rules of the knowledge base for each individual inference object; a working memory selecting unit for performing reading and writing by selecting only the objective working memory from the working memory unit; a parameter storage unit containing parameters provided for respective objects, each parameter being needed when applying the rule of the knowledge base; a parameter selecting unit for reading only the objective parameter for the parameter storage unit; and an inference engine for applying the rule corresponding to contents of the objective working memory from the rules of the knowledge base for one inference object by manipulating the working memory selecting unit and the parameter selecting unit as well.

Abstract: A power conversion device such as an inverter using as bridge arm elements self-extinguishing-type switching elements for converting D-C input power into A-C load power. Snubbers, each including a capacitor and a diode in series, are connected in parallel with the switching elements. A discharging circuit, having a diode is connected across the diodes of the snubbers, and a power source feedback circuit, including a current transformer, are employed to return the current discharged from the snubbers to the input power source, thereby enhancing conversion efficiency.