Expert-system shells lineage: The product named “Personal Consultant” was based on which influential expert-system shell?

Introduction / Context:
Expert-system shells provide the inference engine and knowledge-representation framework for building domain applications. Understanding the lineage of notable shells helps situate commercial tools within the history that began with research prototypes like MYCIN and its generalized derivative EMYCIN (Empty MYCIN). “Personal Consultant” drew from this heritage to make rule-based development more accessible.

Given Data / Assumptions:

• “Personal Consultant” is an expert-system shell product.
• EMYCIN was a generalization of the MYCIN rule-based system.
• OPS5 and XCON are related to production systems and configuration, not the specific base of Personal Consultant.

Concept / Approach:
EMYCIN abstracted MYCIN’s reasoning mechanisms into a reusable shell that others could adapt to new domains by adding knowledge bases. Commercial tools in the same lineage adopted similar rule-chaining approaches (certainty factors, rule slots), providing developers with a ready inference engine plus explanation facilities.

Step-by-Step Solution:

Verification / Alternative check:
Historical overviews of expert-system tools repeatedly link Personal Consultant to the EMYCIN lineage, confirming the association.

Why Other Options Are Wrong:

• OPS5+: influential but not the basis cited for Personal Consultant’s lineage.
• XCON: an application (DEC configurator), not the shell Personal Consultant was based on.
• All/None: do not fit the historical record.

Common Pitfalls:
Confusing an expert-system shell (a framework) with a specific expert application; assuming any famous AI system is the base of all shells.

Final Answer:
EMYCIN