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1980 – 1995

Expert Systems Era

"Knowledge is power: Modeling expertise through structured rules."

Chronology of Knowledge Engineering

1980: Commercialization of Lisp Machines

Dedicated hardware for AI development becomes a billion-dollar industry, allowing companies to run complex symbolic programs.

1982: The Fifth Generation Computer Project

Japan invests heavily in massively parallel computing to leapfrog current AI capabilities, triggering a global AI arms race.

1985: XCON (Expert Configurer) Success

Digital Equipment Corp (DEC) deploys XCON to save millions by automatically configuring computer orders. This proved AI had massive ROI.

1986: The Connectionism Revival

Rumelhart, Hinton, and Williams publish on **Backpropagation**, showing how multi-layer neural networks could finally be trained.

1990s: Cyc Project Expansion

Douglas Lenat begins "Cyc," an ambitious attempt to codify "common sense" into a giant database of millions of assertions.

Core Methodologies & Architecture

Unlike previous "general" AI, Expert Systems separated the "brain" from the "memory":

Inference Engine

The processing unit that applies logical rules to the data to deduce new facts (Forward vs. Backward Chaining).

Knowledge Base

A repository of domain-specific facts and "if-then" rules gathered from human specialists.

Forward Chaining

Starts with known data and applies rules to see what results occur (Data-driven).

Backward Chaining

Starts with a goal (hypothesis) and looks back for data that supports it (Goal-driven).

Why It Transitioned

While successful, these systems were static. They couldn't learn on their own. If a doctor's knowledge changed, the "Knowledge Engineer" had to manually rewrite thousands of lines of code. This led to the 2nd AI Winter when maintenance costs exceeded the benefits.