CYC: The Common Sense Knowledge Base

By: Jeremy BermanAlok Sahgal

Dr. Reed CSC 550

Intro

• History

• What is Cyc?

• How does it work?

• Applications– OpenCyc– CycSecure

History of CYC

• Douglas B. Lenat and MCC (1984)

• GOFAI at a massive scale

• Construct “Common Sense” knowledge– 3 million rules of thumb (2002)– 300,000 terms

The First 10 Years

• Initial Goals (1984)– representation language– Interface for browsing and editing– "cadre of lightly trained knowledge enterers"

could easily use – hooks to other AI programs.

• Midpoint Report (1990)– CycL developed

Current State

• Now, anyone can be knowledge-enterer

• Web allows acceleration of knowledge entry

• Lenat claims human-level capacity in 5 years

How CYC Works

Knowledge Server• Knowledge Base• Inference Engine• CycL• Cyc-NL• Semantic

Integration Bus

Knowledge Base

• Contains facts about everyday life (common sense)

• Terms written in CycL

• Assertions about terms– Entered by humans– Created by Cyc

• Microtheories

Inference Engine

• General logical deduction

• Best-first search

• Due to size, ordinary expert system methods of accessing data do not work.

• Cyc team developed new methods of retrieving data (secret)

CycL

• CycL– Cyc representation language – variation of first-order predicate calculus

CycL

• Constant - #$OrganicStuff 

• NAT - (#$FruitFn #$AppleTree)

• Variable - – (#$colorOfObject #$Grass ?someColor)

• Expression – – (#$colorOfObject #$Grass #$Green)

CycL• Assertions “Animals sleep at home.” (ForAll ?x (ForAll ?S (ForAll ?PLACE(implies (and(isa ?x Animal)(isa ?S SleepingEvent)(performer ?S ?x)(location ?S ?PLACE))(home ?x ?PLACE)))))

if x is an animal and the performer of a sleeping eventthen the place where that event takes place is the home of x.

Cyc-NL• Used to translate between English and CycL

The man saw the light with the telescope.

{:SENTENCE {:NP {:DETP {#$Determiner [the]}} {:N-BAR {#$SimpleNoun [man]}}} {:VP {#$Verb [saw]} {:NP {:DETP {#$Determiner [the]}} {:N-BAR {#$SimpleNoun [light]}} {:PP {#$Preposition [with]} {:NP {:DETP {#$Determiner [the]}} {:N-BAR {#$SimpleNoun [telescope]}}}}}}}}

Cyc-NL

Fred saw the plane flying over Zurich.

Fred saw the mountains flying over Zurich.

• Cyc “knows” that:– planes fly.– people fly in planes.– mountains do not fly.– Zurich is a city.

Semantic Integration Bus

• Makes data from a variety of sources usable to the Inference Engine.

Applications

OpenCyc

• Uses

• Goals of Project

• Demonstration

CycSecure

OpenCyc Uses

Allows user to create applications that access and use data in CycKB

Starting point for:– Speech understanding

– Database integration

– Email prioritizing

– Game engines

– Letting people develop their own “worlds”

OpenCyc

Goals of Project

• Growth of Knowledge Base

• Establish CycKB as the standard for:– knowledge representation/management– database integration – intelligent software applications

OpenCyc

Goals cont.

• Raise awareness for symbolic knowledge

• Help to combine symbolic systems with emergent ones (neural nets, genetic algorithms, etc)

OpenCyc

Demonstration

http://www.opencyc.org/images/opencyc-kb-browser.gif

CycSecure

• Automated network auditing service that simulates network attacks

• First real commercial application

• Complements other network security apps

Anatomy Of CycSecure

• Network Configuration Simulator – Inputs the data for security assessment

• CycSecure Knowledge Base – Contains knowledge of vulnerabilities and

patterns of attacks

• AttackPlan Analyzer – Simulates a planned attack

How CycSecure Works

• Uses virtual network from NCS

• Finds vulnerabilities of network security

• DoD’s Information Assurance Vulnerability Assessment

More about CycSecure

• Evolved Scanner

• Costs

• Still in beta-testing

Future of Cyc

• Online brokering of goods and services

• "Smart" interfaces

• Advancement gaming AI

• Improved speech recognition

• Sophisticated user modeling

• Local consistency

Conclusion

• KB is already enormous and broad

• Large corporate support

• Largest GOFAI attempt

References

• www.cyc.com

• www.opencyc.org

• Anthes, Gary H. Computerizing Common Sense, Computerworld

April 8, 2002.