Rallou Thomopoulos EPI GraphIK In collaboration with: IRIT: L. Amgoud LIRMM: M.L. Mugnier

1. Argumentation to support decision in agri-food chains Rallou Thomopoulos EPI GraphIK In collaboration with: IRIT: L. Amgoud LIRMM: M.L. Mugnier IATE: S. Destercke, J. Fortin PhD thesis: J.R. Bourguet

2. Context Technicity Taste Nutrition WHAT TO DO ? Security Easy-to-use Environment Costs

3. Millers Bakers Consumers Nutritionists Researchers Government (PNNS) Example T65 ? T80 ?

4. Increasing nutritional components Avoiding chemical contamination Decreasing costs Proposing a consumer-attractive bread Controling appetite Limitating irritating fibers Limitating salt consumption Avoiding the responsability for consumer security Reducing costly widespread diseases Maintaining sells Preserving the profession’s technicity Example T65 ? T80 ? ~60 identified arguments

5. Questions • Models for formal representation ? • Support to analyse a complex situation ? • Methods for arbitration (compromise, …) ? • Explanations for a decision ?

6. Formal approach Combination of both = emerging issue 2 existing frameworks of interest: • Argumentation • Multi-criteria decision

7. a a b b Argumentation • Abstract argumentation framework (Dung, 1995) (A,R) with: - A a set of arguments - R an attack relation • Other elements: preferences, contexts, …

8. Argumentation • An argument consists in: • - a set of assumptions (support or premises) • - a conclusion (claim or consequent) • - an implication: the conclusion can be deduced from the assumptions • Different kinds of attack: • - rebutting (negation of the conclusion) • - assumption attack (negation of the assumptions) • - undercutting (negation of the implication)

9. Prise de décision (Argumentation) REBUTTING Example • COM1 argument  economical profit Change in color T65 → T80 Decreased sales Change in texture health benefit  Satiety • COM2 argument awareness campaign T65 → T80  economical profit communication on cereal products

10. Prise de décision (Argumentation) ASSUMPTION ATTACK Example • NUTRI1 argument phytic acid T65 → T80  health benefit biodisponibility of essential cations (Zn,Cu,…) • NUTRI2 argument use of natural yeast (sourdough) T65 → T80 phytic acid Acidity

11. Prise de décision (Argumentation) UNDERCUTTING Example • PNNS argument (part of) Fibers health benefit T65 → T80 • NUTRI3 argument Fibers T65 → T80 insoluble fibers health benefit

12. Argumentation • Notion of « extension » • Several semantics: - naïve extension: no conflicts + maximal - admissible extension: no conflicts + defense - preferred extension: no conflicts + defense + maximal - complete extension: concerns self-defending arguments - stable extension: no conflicts + attacks external arguments - basic extension: recursively defined

13. Prise de décision (Argumentation) Example • Milling argument (MILL) extraction rate T65 → T80  economical profit production cost • Baking argument (BAK) fibers T65 → T80  economical profit water flour

14. Prise de décision (Argumentation) Example NUTRI3 MILL PNNS COM1 NUTRI1 BAK COM2 NUTRI2 PREFERRED EXTENSIONS: • {COM1, NUTRI3, NUTRI2} • {COM2, MILL, BAK, PNNS, NUTRI2} • {COM2, MILL, BAK, NUTRI3, NUTRI2}

15. Argumentation-based decision • Argument = {S,d,g} with: - S the knowledge that supports the argument - d the supported decision - g a goal (Amgoud and Prade, 2009) • A simple mode of decision : choose the option that is supported by most "acceptable" arguments

16. Example T65 ? T80 ? (d) (S) T65 contains less peripheric grain layers  Avoiding chemical contamination Peripheric layers are rich in vitamins and minerals  Increasing nutritional components (g) T80 bread requires less flour and more water  Decreasing costs T65 produces more crusty breads  Proposing a consumer-attractive bread First approach: 6 arguments versus 5  T65 T80 increases satiety  Controling appetite T65 contains more soluble fibers  Limitating irritating fibers T80 is consumed in smaller quantities  Limitating salt consumption T65 provides less contammination risks  Avoiding the responsability for consumer security T80 participates in public health control  Reducing costly widespread diseases The market of T65 bread works well  Maintaining sells T65 involves complex fractionation steps by millers  Preserving the profession’s technicity

17. informed consumers’ 1st goal most consumers’ 1st goal bakers’ 1st goal nutritionists’ 1st goal government’s 1st goal millers’ 1st goal Example T65 ? T80 ? (d) (S) T65 contains less peripheric grain layers  Avoiding chemical contamination Peripheric layers are rich in vitamins and minerals  Increasing nutritional components (g) T80 bread requires less flour and more water  Decreasing costs T65 produces more crusty breads  Proposing a consumer-attractive bread Second approach: Satisfying most actors  T80 T80 increases satiety  Controling appetite T65 contains more soluble fibers  Limitating irritating fibers T80 is consumed in smaller quantities  Limitating salt consumption T65 provides less contammination risks  Avoiding the responsability for consumer security T80 participates in public health control  Reducing costly widespread diseases The market of T65 bread works well  Maintaining sells T65 involves complex fractionation steps by millers  Preserving the profession’s technicity

18. Unified approach

19. Example

20. Example

21. Conclusion • A simplified example of a complex situation • Different possible modes of decision • Interest of the approach: theory, applications and stakes • Sensitive point: dependant on the quality of arguments identification

22. Perspectives • Decision with several viewpoints in the unified approach • A lot to do to facilitate visual representation and analysis • Towards a implemented tool