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Dept. of Computer Science HY577 – Machine Learning EBL University of Crete Fall 2000 course EBL: Explanation Based Learning 00/ EBL: Knowledge-Intensive Learning EBL = Analytical Learning (vs. inductive learning) EBL: The Origins EBG: Explanation Based Generalization EBG: The Basic Entities An example – EBG: The Operations EBL & Theory Revision: Combining EBL with inductive learning The NEITHER theory revision system EBL & ILP: Inductive Logic Programming (… based Learning)

EBL: Explanation Based Learning - FORTHusers.ics.forth.gr/~potamias/hy577/ebl.pdf · 2000. 12. 11. · Dept. of Computer Science HY577 – Machine Learning EBL University of Crete

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  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBL: Explanation Based Learning

    00/

    EBL: Knowledge-Intensive LearningEBL = Analytical Learning (vs. inductive learning)

    EBL: The OriginsEBG: Explanation Based GeneralizationEBG: The Basic EntitiesAn example – EBG: The Operations

    EBL & Theory Revision: Combining EBL with inductive learningThe NEITHER theory revision system

    EBL & ILP: Inductive Logic Programming (… based Learning)

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBL: Knowledge-Intensive Analytical Learning

    01/

    EBL generalize from single example by analyzing whythat example is an instance of the target/ goal concept

    EXPLAIN

    � The Explanation identifies the RelevantRelevant features of the example which constitute SufficientSufficient conditions for describing the target concept

    � The main power of EBL rests on the use of a DOMAIN THEORYDOMAIN THEORYto drive the analysis process

    Knowledge Intensive LearningAnalyticalAnalytical

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Inductive vs AnalyticalAnalytical Learning

    02/

    prototype cases

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Learning: What we would like

    03/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    STRIPS: The Origins of EBL

    04/

    Fikes, Hart, Nilsson, 1972

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBG - Explanation Based Generalization: The ‘mature’ EBL

    05/

    Mitchell, et.al., 1986

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBG: The Basic Entities

    06/

    THEORY REVISION

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBG: The Basic Entities -2

    07/

    EBG

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    An Analytical Generalization Example

    08/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBG: The Operations

    09/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    EBG - The Basic Steps: Compute & Store a Proof

    10/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course 11/

    EBG -The Basic Steps: REGRESSION (= generalize/refine the proof)

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Regression: example

    12/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Combining EBL/EBG with Inductive Learning

    13/

    … by FOCUSING on the structured proofsand identifying conditions (rules) toRemove/ Extend/ Add-on the proofs

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    NEITHER: An Efficient & Effective Theory Revision System

    14/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    NEITHER: The Operations

    15/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    ILP: Inductive Logic Programming

    16/

    ILP

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Induction as Inverted Deduction

    17/

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Deduction as … Resolution

    18/

    Deduction … as resolutionP V LnotL V R----------P V R

    Induction is, in fact, the inverse operation of deduction, and cannot be conceived to existwithout the corresponding operation. Who thinks of asking whether addition or subtraction is the more important process in arithmetic? But at the same time much difference in difficulty may exist between a direct and inverse operation; : : : it must be allowed that inductive investigations are of a far higher degree of difficulty and complexity than any questions of deduction …

    (Jevons 1874)

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    Resolution & Inverting it …

    19/

    1. Given initial clauses C1 and C2, find a literal L from clause C1 such that notL occurs in clause C2

    2. Form the resolvent C by including all literals from C1 and C2,expect for L and notL. More precisely, the set of literals occurringin the conclusion C is:

    C = (C1 – {L}) U (C2 – {notL})

    Inverting Resolution: Example

  • Dept. of Computer Science HY577 – Machine Learning EBLUniversity of Crete Fall 2000 course

    ILP systems

    20/