Context Technicity Taste Nutrition WHAT TO DO ? Easy-to-use Security Environment Costs Example T65 ? Millers T80 ? Bakers Nutritionists Consumers Researchers Government (PNNS) Example T65 ? Avoiding chemical contamination T80 ? Increasing nutritional components Proposing a consumer-attractive bread Decreasing costs Limitating irritating fibers Controling appetite ~60 identified arguments Avoiding the responsability for consumer security Maintaining sells Preserving the profession’s technicity Limitating salt consumption Reducing costly widespread diseases Questions • • • • Models for formal representation ? Support to analyse a complex situation ? Methods for arbitration (compromise, …) ? Explanations for a decision ? Formal approach 2 existing frameworks of interest: • Argumentation • Multi-criteria decision Combination of both = emerging issue Argumentation • Abstract argumentation framework (Dung, 1995) (A,R) with: - A a set of arguments - R an attack relation a b • Other elements: preferences, contexts, … a b 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) Prise de décision (Argumentation) Example COM1 argument T65 → T80 economical profit Change in color Change in texture REBUTTING Satiety Decreased sales health benefit COM2 argument T65 → T80 awareness campaign communication on cereal products economical profit Prise de décision (Argumentation) Example NUTRI1 argument phytic acid T65 → T80 ASSUMPTION ATTACK biodisponibility of essential cations (Zn,Cu,…) health benefit NUTRI2 argument T65 → T80 use of natural yeast (sourdough) Acidity phytic acid Prise de décision (Argumentation) Example PNNS argument (part of) Fibers T65 → T80 health benefit UNDERCUTTING NUTRI3 argument Fibers T65 → T80 insoluble fibers health benefit 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 Prise de décision (Argumentation) Example Milling argument (MILL) extraction rate economical profit T65 → T80 production cost Baking argument (BAK) fibers T65 → T80 water flour economical profit Prise de décision (Argumentation) Example NUTRI3 PNNS MILL COM1 NUTRI1 BAK COM2 NUTRI2 PREFERRED EXTENSIONS: {COM1, NUTRI3, NUTRI2} {COM2, MILL, BAK, PNNS, NUTRI2} {COM2, MILL, BAK, NUTRI3, NUTRI2} 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 Example (d) T65 ? T65 contains less peripheric grain layers Avoiding chemical contamination (S) (g) T65 produces more crusty breads Proposing a consumer-attractive bread T65 contains more soluble fibers Limitating irritating fibers T80 ? Peripheric layers are rich in vitamins and minerals Increasing nutritional components T80 bread requires less flour and more water Decreasing costs First approach: 6 arguments versus 5 T65 provides less contammination risks T65 Avoiding the responsability for consumer security The market of T65 bread works well Maintaining sells T65 involves complex fractionation steps by millers Preserving the profession’s technicity T80 increases satiety Controling appetite T80 is consumed in smaller quantities Limitating salt consumption T80 participates in public health control Reducing costly widespread diseases Example (d) T65 ? T65 contains less peripheric grain layers Avoiding chemical contamination (S) (g) most T80 ? informed Peripheric layers are rich in vitamins and minerals consumers’ 1st goal Increasing nutritional components T65 produces more crusty breads consumers’ Proposing a consumer-attractive bread st 1 goal T65 contains more soluble fibers Limitating irritating fibers T80 bread requires less flour and more water bakers’ Decreasing costs 1st goal T80 increases satiety Controling appetite Second approach: nutritionists’ Satisfying most actors T80 is consumed in smaller quantities st goal T65 provides less contammination risks 1 T80 Limitating salt consumption Avoiding the responsability for consumer security The market of T65 bread works well millers’ 1st goal Maintaining sells T65 involves complex fractionation steps by millers Preserving the profession’s technicity government’s T80 participates in public health control 1st goal Reducing costly widespread diseases Unified approach Example Example 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 Perspectives • Decision with several viewpoints in the unified approach • A lot to do to facilitate visual representation and analysis • Towards a implemented tool