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Invited TalkThe Sixth International Conference on Semantic Technologies
for Intelligence, Defense, and Security – STIDSFairfax, VA, 16 November 2011
Gheorghe Tecuci
Mihai Boicu, Dorin Marcu, David Schum, Kathryn Russell
Learning Agent Center, George Mason University
2011, Learning Agents Center 2
Summary
We present the current status and applications of an evolving theoryand technology for the development of cognitive assistants by subjectmatter experts who are not knowledge engineers or computer scientists.This approach, called Disciple, synergistically integrates mixed-initiativeproblem solving, evidence-based reasoning, teaching, and multistrategylearning, enabling direct teaching of a learning agent by a subject matterexpert.The Disciple approach has been successfully employed to developcognitive assistants in a wide variety of domains, including intelligenceanalysis, modeling of violent extremists, center of gravity determination,course of action critiquing, emergency response planning, and PhDadvisor assessment.It is envisioned that this approach will enable typical computer users todevelop their own personal cognitive assistants for the semantic web.
2011, Learning Agents Center 3
Overview
Discussion
How a Disciple Assistant is Taught and Learns
Research and Development Objectives
Applications of the Disciple Cognitive Assistants
2011, Learning Agents Center 4
Alan Turing
Computing Machinery and
Intelligence
Mind, 59,433-460, 1950.
Building an intelligent machine by programming is too difficult.
“Instead of trying to produce a program to simulate the adult mind, why not rather try to produce one which simulates the child's?
If this were then subjected to an appropriate course of education one would obtain the adult brain.”
Teaching as Alternative to Programming
2011, Learning Agents Center 5
“Rarely does a technology arise that offers such awide range of important benefits of this magnitude.Yet as the technology moved through the phase ofearly adoption to general industry adoption, theresponse has been cautious, slow, and “linear”(rather than exponential).”
Knowledge-Based Cognitive Agents
Edward Feigenbaum
Tiger in a Cage:The Applications of Knowledge-
Based Systems
AAAI 1993Invited Talk
Building knowledge-based cognitive agents isvery difficult because much of expert’s problemsolving knowledge is in the form of tacitknowledge which is very difficult to capture.
KnowledgeEngineer
Subject MatterExpert
Knowledge Base
Inference Engine
Cognitive Agent
ProgrammingDialog
Results
2011, Learning Agents Center 6
The expertteaches the agent
how to solve problems in a way
that resembles how the expert would teach a
student, an apprentice or a collaborator.
The agent continuously develops and
refines its knowledge base to capture and better represent expert’s
knowledge and problem solving
strategies.
Disciple Approach to Cognitive Agent Development
Approach to develop cognitive agents that can be taught directly by subject matter experts to become cognitive assistants.
Main IdeasMixed-initiative problem solving
Evidence-based reasoningTeaching and learningMultistrategy learning
Resulting agent capabilitiesLearning expert knowledgeAssisting experts and non-experts in problem solving
Teaching students
2011, Learning Agents Center 7
Vision: Evolution of Software Development and Use
MainframeComputers
Software systems developed and used by computer experts
DISCIPLE
CognitiveAssistants
Software systems developed and used by
persons who are not computer experts
PersonalComputers
Software systems developed by computer
experts and used by persons who are not
computer experts
2011, Learning Agents Center 8
Vision: Use of Disciple Agents in Education
Personalized Learning: Grand Challenge for the 21st CenturyUS National Academy of Engineering, 2008
teachesDiscipleAgentKB
DiscipleAgentKB
Disciple behaves as a tutoring system, guiding the student through a series of lessons and exercises.
collaborate
A student uses Disciple as an assistant and learns from its
explicit reasoning.
Army Intelligence Center
teachesDiscipleAgent KB
A subject matter expert teaches Disciple similarly to how the
expert would teach a student.
2011, Learning Agents Center 9
Overview
Discussion
How a Disciple Assistant is Taught and Learns
Research and Development Objectives
Applications of the Disciple Cognitive Assistants
Life Cycle of a Disciple Assistant
Knowledge Base Management
MultiStrategyLearningModules
Ontology DevelopmentModules
ProblemSolvingModules
Evidence‐Specific Modules
EBR KB
Scenario KBScenario KB
Domain KBDomain KB Domain KB
Disciple Learning Agent Shell Subject Matter
Expert and Knowledge Engineer
1. ShellCustomization
Developer and Knowledge Engineer
Tutoring ModulesInteraction
Mixed Initiative Interaction
Cognitive AssistantEnd User
End Users
4. Field UseEnd User
Subject Matter Expert and Knowledge Engineer
DiscipleDisciple
Disciple
2011 Learning Agents Center
Develop ontology
Define reasoning
rules
Verify and update rulesand ontology
Very difficult and time-consuming
Model problem solving
SubjectMatter Expert
KnowledgeEngineer
S1
S11 S1
n
S21 S2
m
S31 S3p
QuestionAnswer
QuestionAnswer
QuestionAnswer
P1
P11 P1
n
P21 P2
m
P3pP31
QuestionAnswer
QuestionAnswer
QuestionAnswer
IF the problem to solve is P1
THEN solve its sub-problemsP1 … P1
Supported by minimally generalized cases
PVS Condition
Except-WhenPVS Condition
1 nJane Austin
Ph.D. student
John Doe
faculty memberstaff member
professor
studentuniversity employee
person
Bob Sharp
instance of
subconcept of
instance of instance of
subconcept of
subconcept of subconcept of
subconcept of
M.S. student
B.S. studentinstructor
graduatestudent undergraduate
student
fullprofessor
associateprofessor
assistantprofessor
subconcept of
instance of
subconcept of
Joan Dean
instance of
PhDadvisor
John Smith
graduateresearchassistant
teachingassistant
Learn reasoning
rules
Provide andexplain
examples
Analyze agent’s
solutions
Learnontologyelements
Explainerrors
Assist in problem modeling
Instruct expert to
use model
Easier and faster because many task components are performed or supported by the learning agent.
SubjectMatter Expert
KnowledgeEngineer
LearningAgent
Extend ontology based on modeled
problems
Learn /refinerules
Elicit concepts with hierarchical
organization
KE with Learning Agent Technology
Manual Knowledge Engineering (KE)
Knowledge Base Development and Maintenance Tasks
Under-stand
domain
12
Stages in Knowledge Base Development
Define types of problems to solve
Assessing a potential PhD advisor for a student
Develop ontology based on modeled problems
PhDadvisor
Jane AustinJohn Doe
faculty memberstaff member
professor
university employee
instance of instance of
subconcept of
subconcept of
instructor
fullprofessor
associateprofessor
assistantprofessor
instance of
subconcept of
John Smith
John Doeis expert in
Artificial Intelligence
Bob Sharpis interested in
Computer Science
instance-of
Software Engineering
instance-of
research area
subconcept-of
BiologyMathematics
area of expertise
subconcept-of
Model solutions of typical problems
(rapid prototyping)
S1
S1n
QuestionAnswer
S11
S21
QuestionAnswer
S2m
P1
P11 P1
n
QuestionAnswer
P21 P2
m
QuestionAnswer
S1
S1n
QuestionAnswer
S11
S21
QuestionAnswer
S2m
P1
P11 P1
n
QuestionAnswer
P21 P2
m
QuestionAnswer
S1
S1n
QuestionAnswer
S11
S21
QuestionAnswer
S2m
P1
P11 P1
n
QuestionAnswer
P21 P2
m
QuestionAnswer
Learn rules and refine knowledge base
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
Jane Austin
Ph.D. student
John Doe
faculty member staff member
professor
studentuniversity employee
person
Bob Sharp
instance of
subconcept of
instance of instance of
subconcept of
subconcept of subconcept of
subconcept of
M.S. student
B.S. studentinstructor
graduatestudent undergraduate
student
fullprofessor
associateprofessor
assistantprofessor
subconcept of
instance of
subconcept of
Joan Dean
instance of
PhDadvisor
John Smith
graduateresearchassistant
teachingassistant
employeesubconcept of
subconcept of
S1
S1nS1
1
S21 S2
m
P1
P11 P1
n
P21 P2
mevidence-based reasoning
A problem P1 is solved by:• successively reducing it to simpler and simpler problems; • finding the solutions of the simplest problems; • successively combining these solutions to obtain the
solution of the initial problem.
General Reasoning Model: Divide and Conquer
One of the most highly developed skills incontemporary Western civilization is dissection;the split-up of problems into their smallestpossible components. We are good at it. Sogood, we often forget to put the pieces backtogether again. Alvin Toffler
S31 S3
p
S1
S1n
QuestionAnswer
S11
S21
QuestionAnswer
S2m
QuestionAnswer
P1
"I Keep Six Honest...“ by Rudyard Kipling
I keep six honest serving-men(They taught me all I knew); Their names are What and Why and When And How and Where and Who.
P11 P1
n
QuestionAnswer
P21 P2
m
QuestionAnswer
P3pP3
1
QuestionAnswer
Problem Reduction and Solution Synthesis
Assess whether John Doe would be a good PhD advisor for Bob Sharp.
PhD Advisor Assessment: Overall Logic
It is almost certain that John Doe would be a good PhD advisor with respect to the
professional reputation criterion.
It is very likewould be a gwith respect
student re
It is verwould b
with advis
It is almost certain that John Doe will stay on the faculty of George Mason University for the duration
of dissertation of Bob Sharp.
It is certain that Bob Sharp is interested in the area of expertise
of John Doe.
It is very likely that John Doe would be a good PhD advisor for Bob Sharp.
Assess whether John Doe will stay on the faculty of George
Mason University for the duration of dissertation of Bob Sharp.
Assess whether John Doe would be a good PhD advisor
with respect to the PhD advisor quality criterion.
Assess whether Bob Sharp is interested in the area of expertise
of John Doe.
Which are the necessary conditions?Bob Sharp should be interested in the area of expertise of John Doe who
should stay on the faculty of George Mason University for the duration of the dissertation of Bob Sharp, and should have the qualities of a good PhD advisor.
Assess whether John Doewould be a good PhD advisor
with respect to the professional reputation criterion.
…
Assess whether John Doewould be a good PhD advisor with respect to the quality of
student results criterion.
Which is a PhD advisor quality criterion?
professional reputation criterion
Which is a PhD advisor quality criterion?quality of student results criterion
Yves Kodratoff
PhD Advisor
Hybrid Knowledge Base = Ontology + RulesOntology: Hierarchical representation of both general and domain-
specific conceptsevidence
tangible evidence
testimonial evidence
demonstrative tangible evidence
real tangible evidence
unequivocal testimonial evidence
equivocal testimonial evidence
unequivocal testimonial evidence
based upon direct
observation
authoritative record
missing evidence
unequivocal testimonial evidence
obtained at second hand
testimonial evidence based on opinion
completely equivocal
testimonial evidence
probabilistically equivocal
testimonial evidence
Problem reduction and solution synthesis rules: Specified with the concepts
from the ontology
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Condition
Except-When Condition
1g ng
…Except-When Condition
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
Main Condition
Except-When Condition
1g ng
…Except-When Condition
Main Condition Except-WhenCondition
Except-WhenCondition
Reasoning tree:Finding the solution of a
specific problem
S1
S1 S1
S2 S2P2P2
P1P1
P1
…
…
S3 S3P3P3 …
1 1 n n
1 1 m m
1 1 p p
2011 Learning Agents CenterJane Austin
Ph.D. student
John Doe
faculty member staff member
professor
studentuniversity employee
person
Bob Sharp
instance of
subconcept of
instance of instance of
subconcept of
subconcept of subconcept of
subconcept of
M.S. student
B.S. studentinstructor
graduatestudent undergraduate
student
fullprofessor
associateprofessor
assistantprofessor
subconcept of
instance of
subconcept of
Joan Dean
instance of
PhDadvisor
John Smith
graduateresearchassistant
teachingassistant
employeesubconcept of
subconcept of
Learned with an evolving ontology
16
Partially Learned Rules and Evolving Ontology
IF the problem to solve is P1
THEN solve its sub-problemsP1 … P1
PVS Condition
Except-WhenPVS Condition
1 n
S1
S11 S1
n
S21 S2
m
S31 S3p
QuestionAnswer
QuestionAnswer
QuestionAnswer
P1
P11 P1
n
P21 P2
m
P3pP31
QuestionAnswer
QuestionAnswer
QuestionAnswer
Partially learned
rules with plausible version space (PVS)
conditions
+
-
PVS Condition Except-WhenPVS Condition
Reasoning Tree
Mixed-Initiative Problem Solving
AcceptReasoning Step
RejectReasoning Steps
Rules Refinement
Problem
ExtendReasoning Tree
ExplainExamples
Rules Learning
ExplainExamples
ExplainExamples
Refined Rules
Refined Ontology
Learned Rules
Modeling, Learning, and Problem Solving
Ontology + RulesS3
1 S3p
S11
S21
QuestionAnswer
S2m
QuestionAnswer
P1
P11 P1
n
QuestionAnswer
P21 P2
m
QuestionAnswer
P3pP31
QuestionAnswer
18
The subject matter expert helps the agent to learn (e.g. byproviding examples, hints, and explanations), and the agenthelps the expert to teach it (e.g. by presenting attemptedsolutions to problems and by asking relevant questions).
Integrated Teaching and Learning
Input knowledge
Problem solving behavior
Explicit learning guidance
Explicit teaching guidance
Explanations, hints and answers to
agent’s questions
Problem solving examples
Attempted solutions to problems
Questions
P1
P11 P1
n
Question QAnswer A
…
Example
Rule Learning Method
Knowledge Base
1. Ontology-based mixed-initiative understanding
f1
ob1 ob2
ob3
f2
Explanation
Knowledge Base
3. Minimal and maximal ontology-based generalizations guided by analogical reasoning
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
1g ng
QgAg
Applicability condition
2. Example and explanation
reformulation
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
1g ng
QgAg
?O1 is ob1f1 ?O3
?O2 is ob2f2 ?O3
?O3 is ob3
20
The expert makes explicit how to solve a
problem
1. Modeling
Modeling and Learning
LearnedRule2
LearnedRule1
The agent learns reduction rules
2. Learning
The expert and the agent
identify formal
explanations of the
reductions
Understand Why the Example Is Correct
Approximate representation of the
meaning of the question and its
answer in the ontology.
John Doe
Artificial Intelligenceis expert inis interested in
Bob Sharp
Likelihood of solution is always certain
An even better formulation of the answer is:Yes, this is certain because Bob Sharp is
interested in Artificial Intelligence which is the area of expertise of John Doe.
John Doe
PhD advisor
Bob Sharp
instance of instance of
PhD student
employee
subconcept of
person
associate professor
subconcept of
graduate student
student
subconcept of
professor
faculty member
university employee
actor
object
Artificial Intelligence
Computer Science
area of expertise
instance of
feature
domain
range
personis interested in
subfeature of
area of expertise
Object ontology
subconcept of
?O1 is Bob Sharpis interested in?O3
?O2 is John Doeis expert in ?O3
?O3 is Artificial Intelligence?SI1 is-exactly certain?O3
?O1?O2
Feature ontology
Min - Max Generalizations
IF the problem to solve is P1g
THEN solve its sub-problemsP1 … P1
1g ng
QgAg
?O1 is ob1f1 ?O3
?O2 is ob2f2 ?O3
?O3 is ob3
UB
UB
?O1 is personis interested in?O3
?O2 is personis expert in ?O3
?O3 is area of expertise?SI1 is-exactly certain
Plausible UpperBound Condition (UB)
Max generalization
LB
LB
LB
LB
?O1 is PhD studentis interested in?O3
?O2 is {associate professor, PhD student}
is expert in ?O3?O3 is Artificial Intelligence?SI1 is-exactly certain
Plausible LowerBound Condition (LB)
Min generalization
Positive example
Explanation generalizations
Learned rulePartially learned applicability
condition and rule
Pattern generation
24
Agent applies learned rules to
solve new problems
3. Solving
Expert accepts or
rejectsindividualreductions
4. Critiquing
Solving, Critiquing, and Refining
Agent refines learned rules with the new positive and
negative examples
5. Refining
RefinedRule1
RefinedRule2
25
Failureexplanation
Examples of problem reductions generated by agent
Incorrectexample
Learning fromExplanations
Learning by Analogyand Experimentation
Learning from Examples
Knowledge Base
Refinement Strategy: PVS Condition Refinement
_++
Tom Mitchell
Version spaces: A candidate elimination approach to rule learning
IJCAI 1977
OptionalExplanation
Correctexample
Rule’s main condition
?O1 is Bob Sharpis interested in ?O3
?O2 is Dan Smithis expert in ?O3
?O3 is Information Security?SI1 is-exactly certain
Condition corresponding to the example
26
Positive example
Rule Generalization
Generalized lower bound
27
Solving, Critiquing, and Refinement
Agent applies learned rules to solve new problems1. Solving
2. Critiquing
Incorrect because
Dan Smith plans to
retire
3. Refinement
Agent refines rule with negative example
+
+-
28
Failureexplanation
Example of problem reductionsgenerated by the agent
Incorrectexample
Correctexample
Learning fromExplanations
Learning by Analogyand Experimentation
Learning from Examples
Knowledge Base
IF we have to solve<Problem>
THEN solve<Sub-problem 1>…<Sub-problem m>
MainPVS Condition
Except-WhenPVS Condition
Refinement Strategy: Except-When PVS Condition
+-
29
Rule SpecializationNegative example
Rewrite as
?O1 is Dan Smithplans to retire from ?O2
?O2 is George Mason University
Except when condition
Refined rule
+-
Dan Smith plans to retire from George Mason University
Failure explanation
30
Solving, Critiquing, and Refinement
Agent applies learned rules to solve new problems1. Solving
2. Critiquing
Incorrect because
Jane Austin
plans to move
3. Refinement
Agent refines rule with negative example
+-
+ --
31
Rewrite as
?O1 is Jane Austinplans to move to ?O6
?O5 is Indiana University
Except when condition
Refined rule
Jane Austin plans to move to Indiana UniversityFailure explanation
Negative example
+ --
32
Agent applies learned rules to
solve new problems
1. Solving
Solving, Modeling, and Learning
2. Modeling
Expert extends the reasoning
tree
Agent learns a new rule
3. Learning
+
33
Rule Learning
Example andexplanation
Learned rule
Partially learned applicability condition
and rule
34
Solving, Critiquing, and RefinementAgent applies learned rules to solve new problems1. Solving
2. Critiquing
Incorrect because of the “even chance”
likelihood
3. Refinement
Agent refines rule with negative example
+
+ -
35
Explain Why the Problem Reduction Is Incorrect
Failure explanation proposed by
the agent
Negative example
Refined rule
36
Refined RuleNegative example
Specialized upper bound
Failure explanation
Main condition
37
ProblemSolving
Modeling
LearningExpert
example
Rule-basedguidance
Creativesolution
Context forcreative solution
Refinedrule
Newexamples
Synergy of Modeling, Learning, and Problem Solving
Modeling, learning, and problem solving mutually
support each other to capture tacit knowledge
Mixed-Initiative
Reasoning
38
Features of the Disciple Learning Method
Uses multistrategy learning (examples, explanations, analogy)
Learns rapidly from a small number of examples
Learns even in the presence of exceptions
Captures expert’s tacit knowledge
Is applicable to complex real-world domains
+
-
2011, Learning Agents Center 39
Overview
Discussion
How a Disciple Assistant is Taught and Learns
Research and Development Objectives
Applications of the Disciple Cognitive Assistants
40
Course of Action Critiquing
Workaround Reasoning
Applications of the Disciple Cognitive Assistants
Center of Gravity Determination
Web Believability Evaluation
Modeling of Violent Extremists
Regulatory Compliance in Financial Services Industry
Emergency Response Planning
PhD Advisor Assessment
Intelligence Analysis
This research was performed in the Learning Agents Center and wassupported by George Mason University and by several agencies ofthe U.S. Government, including the Department of Defense, theNational Geospatial-Intelligence Agency, the Intelligence Community,the Air Force Office of Scientific Research, the Air Force ResearchLaboratory, the Defense Advanced Research Projects Agency, theNational Science Foundation, the U.S. Army War College, and theJoint Forces Staff College.
The views and conclusions contained in this document are those ofthe authors and should not be interpreted as necessarilyrepresenting the official policies or endorsements, either expressedor implied, of the U.S. Government.
The U.S. Government is authorized to reproduce and distributereprints for Government purposes notwithstanding any copyrightnotation thereon.
Acknowledgements