820 likes | 853 Views
The SNePS Approach to Cognitive Robotics. Stuart C. Shapiro Department of Computer Science and Engineering and Center for Cognitive Science University at Buffalo shapiro@cse.buffalo.edu. Outline. Introduction Intensional Representation & Propositions SNePS Connectives and Quantifiers
E N D
The SNePS Approach to Cognitive Robotics Stuart C. Shapiro Department of Computer Science and Engineering and Center for Cognitive Science University at Buffalo shapiro@cse.buffalo.edu S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
Goal • A computational cognitive agent that can: • Understand and communicate in English; • Discuss specific, generic, and “rule-like” information; • Reason; • Discuss acts and plans; • Sense; • Act; • Remember and report what it has sensed and done. S.C. Shapiro
Embodied Cassie • A computational cognitive agent • Embodied in hardware • or Software-Simulated • Based on SNePS and GLAIR. S.C. Shapiro
SNePS • Knowledge Representation and Reasoning • Propositions as Terms • SNIP: SNePS Inference Package • Specialized connectives and quantifiers • SNeBR: SNePS Belief Revision • SNeRE: SNePS Rational Engine • Interface Languages • SNePSUL: Lisp-Like • SNePSLOG: Logic-Like • GATN for Fragments of English. S.C. Shapiro
GLAIR Architecture Grounded Layered Architecture with Integrated Reasoning Knowledge Level NL SNePS Perceptuo-Motor Level Sensory-Actuator Level Vision Sonar Motion Proprioception S.C. Shapiro
Interaction with Cassie (Current) Set of Beliefs [SNePS] English (Statement, Question, Command) Reasoning Clarification Dialogue Looking in World GATN Parser (Updated) Set of Beliefs [SNePS] (New Belief) [SNePS] Answer [SNIP] Actions [SNeRE] GATN Generator Reasoning English sentence expressing new belief answering question reporting actions S.C. Shapiro
Cassie, the BlocksWorld Robot S.C. Shapiro
Cassie, the FEVAHR S.C. Shapiro
FEVAHR/Cassie in the Lab S.C. Shapiro
FEVAHRWorld Simulation S.C. Shapiro
UXO Remediation Cassie Corner flag Field Drop-off zone UXO NonUXO object Battery meter Corner flag Corner flag Recharging Station Cassie Safe zone S.C. Shapiro
Crystal Space Environment S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
Entities, Terms, Symbols, Objects • Cassie’s mental entity: a person named Bill • SNePS term: B5 • Object in world: S.C. Shapiro
Intensional Representation Intensional entities are distinct even if coreferential. “The morning star is the evening star.” “George IV wondered if Scott was the author of Waverly.” S.C. Shapiro
McCarthy’s Telephone Number Problem Mary's telephone number is Mike's telephone number. I understand that Mike's telephone number is Mary's telephone number. Pat knew Mike's telephone number. I understand that Pat knew Mike's telephone number. Pat dialed Mike's telephone number. I understand that Pat dialed Mike's telephone number. S.C. Shapiro
Answering the Telephone Number Problem Did Pat dial Mary's telephone number? Yes, Pat dialed Mary's telephone number. Did Pat know Mary's telephone number? I don't know. S.C. Shapiro
Representing Propositions Propositions must be first-class entities of the domain Represented by terms. S.C. Shapiro
Discussing Propositions That Bill is sweet is Mary's favorite proposition. I understand that Mary's favorite proposition is that Bill is sweet. Mike believes Mary's favorite proposition. I understand that Mike believes that Bill is sweet. S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
Logic for NLU &Commonsense Reasoning Either Pat is a man or Pat is a woman or Pat is a robot. I understand that Pat is a robot or Pat is a woman or Pat is a man. Pat is a woman. I understand that Pat is a woman. What is Pat? Pat is a woman and Pat is not a robot and Pat is not a man. S.C. Shapiro
Representation in FOPL? Man(Pat) Woman(Pat) Robot(Pat) S.C. Shapiro
Representation in FOPL? Man(Pat) Woman(Pat) Robot(Pat) but don’t want inclusive or S.C. Shapiro
+ + Representation in FOPL? Man(Pat) Woman(Pat) Robot(Pat) but don’t want inclusive or Man(Pat) Woman(Pat) Robot(Pat) T T T F T So don’t want exclusive or either S.C. Shapiro
andor andor(i, j){P1, ..., Pn} True iff at least i, and at most j of the Pi are True S.C. Shapiro
thresh thresh(i, j){P1, ..., Pn} True iff either fewer than i, or more than j of the Pi are True Note: thresh(i, j) ~andor(i, j) S.C. Shapiro
or-entailment {P1, ..., Pn} v=> {Q1, ..., Qn} True iff for all i, j Pi Qj S.C. Shapiro
and-entailment {P1, ..., Pn} &=> {Q1, ..., Qn} True iff for all j P1 &…& Pn Qj S.C. Shapiro
Numerical entailment {P1, ..., Pn} i=> {Q1, ..., Qn} True iff for all j andor(i, n){P1, …, Pn }Qj S.C. Shapiro
Universal Quantifier all(ū)({R1(ū),..., Rn(ū)} &=> {C1(ū),..., Cm(ū)}) Every ā that satisfies R1(ū)&…& Rn(ū) also satisfies C1(ū),..., Cm(ū)}) S.C. Shapiro
Numerical Quantifiers nexists(i,j,k)(x) ({P1(x),..., Pn(x)}: {Q(x)})} There are k individuals that satisfy P1(x) ... Pn(x) and, of them, at least i and at most j also satisfy Q(x) S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
MENTAL ACTS • Believe(proposition) • Disbelieve(proposition) S.C. Shapiro
Act Selection • Do-One({act1 ... actn}) • Snif(if(condition, act), ... if(condition, act) [else(act)]) S.C. Shapiro
Act Iteration • Do-All({act1 ... actn}) • Sniterate(if(condition, act), ... if(condition, act), [else(act)]) • Snsequence(act1, ..., actn) • Cascade(act1, ..., actn) • P-Do-All({act1, ..., act2}) S.C. Shapiro
Entity Iteration WithSome(var, suchthat, do, [else]) WithAll(var, suchthat, do, [else]) WithSome+(var, suchthat, do, [else]) WithNew(vars, thatare, suchthat, do, [else]) S.C. Shapiro
Proposition/Act Transformers • Achieve(proposition) • ActPlan(act, plan) • GoalPlan(proposition, act) • Precondition(act, proposition) • Effect(act, proposition) • WhenDo(proposition, act) • WheneverDo(proposition, act) • IfDo(proposition, act) S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
Conditional Plans If a block is on a support then a plan to achieve that the support is clear is to pick up the block and then put the block on the table. all(x, y) ({Block(x), Support(y), On(x, y)} &=> {GoalPlan(Clear(y), Snsequence(Pickup(x), Put(x, Table)))}) STRIPS-like representation: No times S.C. Shapiro
Use of Conditional Plan GoalPlan(Clear(B), Snsequence(Pickup(A), Put(A, Table))) Remember (cache) derived propositions. S.C. Shapiro
Use of Conditional Plan GoalPlan(Clear(B), Snsequence(Pickup(A), Put(A, Table)))??? SNeBR to the rescue! S.C. Shapiro
A FEVAHR Acting Rule all(p, o) ({Agent(p), Thing(o)} &=> {Precondition(Follow(p, o), Near(p, o)), GoalPlan(Near(p, o), Goto(p, o)), Precondition(Goto(p, o), Lookat(p, o)), ActPlan(Lookat(p, o), Find(p, o))}) Uses a temporal model. S.C. Shapiro
Acting According to the Rule S.C. Shapiro
Acting According to the Rule Follow a red robot. I found a red robot. I am looking at a red robot. S.C. Shapiro
Acting According to the Rule Follow a red robot. I found a red robot. I am looking at a red robot. I went to a red robot. I am near a red robot. I am following a red robot. S.C. Shapiro
A Plan for Blowing up UXOs all(a)(Agent(a) => ActPlan(Blowup(a, UXOs), Act(a, Cascade(SearchforUxo(a), WithSome+(obj, Near(a, obj), WithNew({ch ex}, {Charge(ch), Explosion(ex)}, Possess(a, ch), Cascade(Place(a, ch, obj), Hide(a), Waitfor(a, ex), SearchforUxo(a))), goto(a, SafeZone)))))) S.C. Shapiro
Outline • Introduction • Intensional Representation & Propositions • SNePS Connectives and Quantifiers • SNeRE Acting Constructs • Example Plans • Representation and Use of Indexicals • A Personal Sense of Time • Summary S.C. Shapiro
Representation and Use of Indexicals • Words whose meanings are determined by occasion of use • E.g. I, you, now, then, here, there • Deictic Center <*I, *YOU, *NOW> • *I: SNePS term representing Cassie • *YOU: person Cassie is talking with • *NOW: current time. S.C. Shapiro
Analysis of Indexicals(in input) • First person pronouns: *YOU • Second person pronouns: *I • “here”: location of *YOU • Present/Past relative to *NOW. S.C. Shapiro