MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 A Role of Dialogue Strategy in Multiattribute Classification Performance Eugenia Furems Institute for System Analysis of Russian Academy of Sciences

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 A Role of Dialogue Strategy in Multiattribute Classification Performance Outline 1.Verbal Decision Analysis (VAR) – principles & methods 2.Knowledge-based multiattribute classification 3.Cognitive difficulties & their avoidance 4.VDA-based method for Nominal-Ordinal Classification (NORCLASS) 5.Advantages and Disadvantages of NORCLASS 6.Modification of NORCLASS dialogue and its effectiveness 7.Conclusion

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Verbal Decision Analysis – Principles Human (DM’s, expert’s) judgements (in verbal or, in other words, qualitative form) - the primary source of information for decision making problems solving Processing such information without any quantitative conversion, so that any resulting conclusion is both transparent and well- explainable to the DM/expert.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Verbal Decision Analysis - Methods Problems Multicriteria Choice Problem Classification problem Preference-based multicriteria classification Knowledge-based multiattribute classification ZAPROSUniComBos ORCLASS, DIFCLASS, CLARA NORCLASS STEPCLASS

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Knowledge-based Multiattribute Classification Assigning the given objects, described with the values upon multiple attributes, to the classes* (from their pre-defined set) according to the expert knowledge. * Class - a set of objects in respect of which the expert makes the same (classification, diagnostic, etc.) decision.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Cognitive Problems & Their Avoidance “An Expert knows more than he/she is able to say” Although an expert would be able to list some classification rules directly, most certainly these rules would be applicable to the typical objects only. So, the set of such rules would be incomplete both in regard of the domain coverage, and in relation to his/her knowledge. Cause: an expert does not formulate the rules in his/her daily activity, but he/she applies them while analyzing the real-world objects. Way out: Simulating objects to be classified and presenting them to the expert for analysis and classification.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Prerequisites for VDA-based Multiattribute Classification Methods 1.Completeness of the expert-specified rules, that allow to classify each object from the set of all hypothetically possible objects in the given application domain described by the values of the expert-specified attributes. 2.Consistency of rules: Any number of rules may be specified for an object; however, all of these rules have to assign it to the same class 3.Avoidance of exhaustive search while the expert’s classification rules eliciting.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 VDA-based method NORCLASS NORCLASS is designed for NOminal-ORdinal CLASSification, where classes correspond to non-orderable decisions, but the expert is able to order the values of each and every attribute according to their inherence in (typicality to) each such class independently of the values of other attributes. : _________________________________________________________________________________ Larichev O, Moshkovich H, Furems E et al (1991) Knowledge Acquisition for the Construction of the Full and Contradiction Free Knowledge Bases. Iec ProGAMMA, Groningen, The Netherlands.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Example Localization of Pain Myocardial Infarction Stenocardia The retrosternal pain12 The pain left to sternum31 The pain under the left scapula23 1 – the most inherent, 3 – the least inherent

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Formal Statement of Multiattribute Classification Problem in NORCLASS It is given: − the names of classes pre-defined by the expert; − the names of attributes, values of which describe the features of objects of the given Application Domain (AD) − the values (the scale) of the m-th attribute A=K 1 xK 2 x…xK M − the set of M-attribute descriptions of all hypothetically possible objects of the AD; It is required: Assign the objects from A to classes from C on the basis of the expert’s knowledge so that the resulting classification is both complete (up to the expert’s knowledge) and consistent

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Ordering by Inherence −reflexive and transitive binary relations over Q m ’s values, such that (k mi,k mj )  R l m, if, according to the expert judgement, k mi is not less inherent in (typical to) C l than k mj ; m=1,…,M; l = 1, …,L. Relations of Dominance by Inherence in a correspondent class

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Rules in NORCLASS 1.If the expert assigns an object a i to the class C l, any object a j, such that (a j, a i )  R l, belongs to C l as well. 2.If, according to the expert judgement, an object a i, does not belong the class C l, any object a j, such that (a i, a j )  R l, does not belong to C l as well. Violation of the rules above means the expert’s error and has to be corrected once it has been revealed.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 NORCLASS Rules’ Effects C1C1 C2C2 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,1,2,12,2,1,1 1,1,2,31,2,1,31,2,2,22,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,2,2,3 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,2,1,12,1,2,1 1,1,2,31,2,1,31,2,2,2 2,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,2,2,3 a1a1 a2a2 a4a4 a7a7 a 13 a5a5 a8a8 a 10 a 14 a 16 a 19 a6a6 a9a9 a 11 a 15 a 17 a 20 a 22 a 12 a 18 a 21 a 23 a 24 a 23 a 24 a 20 a 17 a 11 a 22 a 21 a 18 a 14 a 12 a8a8 a5a5 a 19 a 16 a 15 a 10 a9a9 a6a6 a2a2 a 13 a7a7 a4a4 a3a3 a1a1 a3

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Advantages and Disadvantages of NORCLASS AdvantagesDisadvantages 1.NORCLASS is based on so called Inherence Hypothesis (IH): an expert is able to order the values of any attribute independently of the values of other attributes. IH-based rules allow to reduce significantly (up to 65% in average) a number of objects presented to an expert directly. 1.NORCLASS doesn’t provide for any aids for problem structuring. Classes, attributes, values and binary relations are revealed informally. 2.Non-flexible dialogue with an expert: he/she is presented M- attribute objects as whole, while the expert may need a part of such information only. 3.It is impossible to add a new class, attribute or value in the course of classification. 2.NORCLASS allows to construct the complete (up to the expert knowledge) and consistent set of classification rules.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Modifications for NORCLASS Effectiveness Improvement 1.Restatement a problem to include the formal phase of its structuring*. 2. Changing the dialogue strategy in order to: make it more flexible and, thus, less cognitively onerous for en expert; reduce further a number of questions to be asked to an expert in a view of his/her classification rules eliciting; provide for additional possibilities for rules’ consistency control *Eugenia M. Furems. Domain Structuring For Knowledge-Based Multiattribute Classification (A Verbal Decision Analysis Approach) (2010) TOP, Springer Berlin / Heidelberg, DOI /s

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Reformulation a problem Multiattribute classification problem is stated as two interrelated sub-problems: It is given: Some Application Domain each object of which may belong to one or more classes It is required: 1.To define the Structure of the Application Domain, i.e., 2.To assign each a i  A (A= K 1 x K 2 x … x K M ) to a class/classes from C on the basis of the expert’s knowledge so that the resulting classification is both complete (up to the expert’s knowledge) and consistent.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Explicit Structuring (Pre-defined Classes C 1, C 2, C 3 ) ATTRIBUTES Q1Q1 Q2Q2 Values of Q 1 for C 1 k 11 k 12 Other classes k 11 is admissible for C2C2 C3C3 Other values of Q 1 for C 2 k 13 Other classes k 13 is admissible for C3C3 Other classes k 12 is admissible for C3C3 Other values of Q 1 for C 3 k 14 Other classes k 14 is admissible for C1C1 apart from C 1 apart from k 11 apart from C 2 apart from k 11,k 1,3 C4C4 apart form C 1 apart from C 3

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Structuring by Examples Example for C 1 If &, then C1 A is a value of Q 1 (k 11 =A) B is a value of Q 2 (k 21 =B) Other classes k 11 is admissible for C2C2 C3C3 Other values for C 2 k 13 Other classes k 31 is admissible for C1C1 C3C3 Example for C 2 If &, then C 2 D is a value of Q 2 (k 22 =D) E is a value of Q 3 (k 31 =E)

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Classification Rules Elicitation a i =(x 1,x 2,x 3,x 4 ), x m  K m System: x2x2 Expert Q3?Q3? System x2x3x2x3 Expert Q4?Q4? Extension the Rule according to Dominance Inherence: If ‘any value’ of Q 1, and any k 2i, such that (k 2i, x 2 )  R 1 2, and any k 3j, such that (k 3j,x 3 )  R 1 3, and any k 4s, such that (k 4s, x 4 )  R 1 4, than C 1 System x2x3x4x2x3x4 Expert: C 1 Rule: If ‘any value’ of Q 1, and x 2 upon Q 2, and x 3 upon Q 3, and x 4 upon Q 4, than C1

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Effect of Dialogue Strategy Modification (Class C 1 ) BeforeAfter 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,1,2,12,2,1,1 1,1,2,31,2,1,31,2,2,22,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,2,3,3 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,2,1,12,1,2,1 1,1,2,31,2,1,31,2,2,2 2,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,,2,3,3 a1a1 a2a2 a4a4 a7a7 a 13 a5a5 a8a8 a 10 a 14 a 16 a 19 a6a6 a9a9 a 11 a 15 a 17 a 20 a 22 a 12 a 18 a 21 a 23 a 24 a1a1 a2a2 a4a4 a7a7 a 13 a3a3 a5a5 a8a8 a 10 a 14 a 16 a 19 a6a6 a9a9 a 11 a 15 a 17 a 20 a 22 a 12 a 18 a 21 a 23 a 24 a3a3

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Effect of Dialogue Strategy Modification (Class C 2 ) BeforeAfter 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,1,2,12,2,1,1 1,1,2,31,2,1,31,2,2,22,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,,2,3,3 1,1,1,1 1,1,1,21,1,2,11,2,1,12,1,1,1 1,1,1,31,1,2,21,2,1,21,2,2,12,1,1,22,2,1,12,1,2,1 1,1,2,31,2,1,31,2,2,2 2,1,1,32,1,2,22,2,1,22,2,2,1 1,2,2,32,1,2,32,2,1,32,2,2,2 2,,2,3,3 a 23 a 24 a 20 a 17 a 11 a 21 a 18 a 14 a 12 a8a8 a5a5 a 19 a 16 a 15 a 10 a9a9 a6a6 a2a2 a 13 a7a7 a4a4 a3a3 a1a1 a 23 a 24 a 20 a 17 a 11 a 22 a 21 a 18 a 14 a 12 a8a8 a5a5 a 19 a 16 a 15 a 10 a9a9 a6a6 a2a2 a 13 a7a7 a4a4 a3a3 a1a1 a 22

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 AD Structure Adjustment Expert has opportunity to specify a new class He/she is asked to determine admissibility of all values of the attributes from the current set Q to such class before to proceed to the next object classification. Expert has opportunity to inquire about a new attribute He/she names it, lists all of its possible values and specifies their correspondent admissibility to the classes. The first value of the new attribute is added to the description of the object under consideration, and it is presented to the expert in addition to information she/he knows already for such object Expert points out incompatible values in the object’s description All objects with such incompatible values’ combinations are excluded from the set A.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Additional Consistency Control Possible contradictions: 1.The expert specifies a rule for a class with the value(s) in left-hand part, he/she determined as inadmissible to the class at the stage of structuring 2.The rule elicited last is inconsistent with the rules elicited previously.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Explicit Rules Inconsistency Rule 1 If any value of Q 1, and x 2 upon Q 2, and x 3 upon Q 3, and x 4 upon Q 4, then C 1 If x 1 upon Q 1, and x 2 upon Q 2, and x 3 upon Q 3, and x 4 upon Q 4, then C 1 Rule 2 If x 1 upon Q 1, and x 2 upon Q 2, and any value of Q 3, and x 4 upon Q 4, then C 2 If x 1 upon Q 1, and x 2 upon Q 2, and x 3 upon Q 3, and x 4 upon Q 4, then C 2 Contradiction

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Conclusions 1.VDA-based techniques for multiattribute classification use only those operations of eliciting information from a DM/expert and such information processing so that both intermediate and resulting conclusions are traceable (well- explainable) to the expert. 2.Proposed modification of a dialogue strategy for NORCLASS allows to make an expert’ knowledge acquisition more close to his/her routine practice, and, thus, to facilitate for him/her the rules’ eliciting procedure. 3.In addition, proposed modification allows to eliminate disadvantages of NORCLASS (absence of preliminary structuring procedures, non-flexible dialogue, impossibility of new classes, attributes and their values specification, etc.) and to reduce further the number of objects to be presented the expert directly for his/her classification rules eliciting.

MCDM 2011, Jyvaskyla, Finland, June 13-17, 2011 Thank You!