Sweetening Regulated Open Multi-Agent Systems with a Formal Support for Agents to Reason About Laws Carolina Howard Felicíssimo Key points of my paper to the AAMAS, 2006 … trying my qualification ! Semantic

Carolina Howard Felicíssimo © LES/PUC-Rio Outline Introduction An Independent-Domain Ontology for Regulations in Open MAS (A Generic Normative Ontology) Case Study –Ontology Extension –Ontology Instantiation –Implementation Related Works Conclusions

Carolina Howard Felicíssimo © LES/PUC-Rio Introduction Provide a Semantic Support for Agents to Reason About Laws in Regulated Open MAS What to do? –Define an approach to specify open MAS’ laws Define guidelines for the implementation of regulations in open MAS –Choose the formalism(s) to be used The more expressive the language, the harder the reasoning !!! How to balance expressiveness and reasoning? –Identify the trade-offs about the choice Benefits: –Automation of part of the laws’ definitions (Ex.: by inference of inherited laws) –Check consistency among laws –Agents can be treat as black-boxes when reasoning about laws

Carolina Howard Felicíssimo © LES/PUC-Rio An Independent-Domain Ontology for Regulations in Open MAS Top-Down Modeling - Different (Interaction) Laws’ Levels: Environment’s Laws: –Those that are applied to all entities from the environment –Are independent of existing organizations, roles being played and interactions Organization’s Laws: –Those that are applied to all entities from the organization –Are independent of roles being played and interactions Role’s Laws: –Those that are applied to all entities playing the role –Are independent of interactions Interaction’s Laws: –Those that are applied to all entities involved in the interaction Exceptions: union of disjoint sets: the “perfect world” plus the exceptions –Ex.: Elephants: union of the gray elephants + albino elephants

Carolina Howard Felicíssimo © LES/PUC-Rio An Independent-Domain Ontology for Regulations in Open MAS

Carolina Howard Felicíssimo © LES/PUC-Rio An Independent-Domain Ontology for Regulations in Open MAS Dell Dell Brazil Supplier Manufacturer Dell Uruguai Supplier Manufacturer HP Customer South America HP Brazil Supplier Manufacturer Distributor Retailer HP Argentina Supplier Manufacturer Distributor Retailer

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study TAC Environment’s Laws: –Trading designed to benefit some other agent at the expense of the trader's own utility –Denial-of-service attacks. Agents may not employ API operations for the purpose of occupying or loading the game servers –Organizations cannot be composed by more than six manufactures –The main organization TAC has a fixed life time of 220 days –To get in, agents have to connect to a game server

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Organizations’ Laws: –Human intervention is not allowed –Is allowed to carry a negative balance in agents’ bank account –Independent of all roles from the organization, sales can just be made between the roles: –Suppliers and manufactures or –Manufactures and customers TAC Supply Chain: (model: direct sales to customer) Supplier -> Manufacturer -> Customer

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Roles’ Laws: –Supplier Only complete orders are shipped Exception: in the last day of the game, partial orders will be shipped Orders are not shipped before their due dates Every order has a down payment of 10% Suppliers operate in make-to-order basis If multiple days of production are required to satisfy an order, inventory is carried over. Inventory carrying costs are assumed to be zero

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Roles’ Laws: –Manufacture Every shipped orders must be paid Every manufacture has an assembly cell that cannot process more than 2000 cycles/day Every manufacture can only produce if all the required components are available inventory Every manufacture can only ship products if they are available in the inventory Every manufacture with inventory of finished goods and components will be charged a daily storage cost of 25% - 50% of the nominal price of components

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Roles’ Laws: –Customer Every RFQs has to have: –Product Type –Quantity Due Date –Reserve Price –Penalty amount –Maximum price per unit that the customer is willing to pay Every shipped orders must be paid The valid bid with the lowest price has to be chosen A randomly choice has to be made when valid bids tied

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Interactions’ Laws: –Laws between Manufactures and Suppliers: Suppliers have to answer all manufactures’ RFQs Manufactures can only send 5 RFQs/day to each supplier for each of the products offered Suppliers have to ignore subsequent orders if more than one type (partial offer or earliest complete offer) was done in a day –Laws between Manufactures: A manufacture cannot sell to another manufacture

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study Interactions’ Laws: –Laws between Manufactures and Customers: Bid of manufactures must address the entire quantity specified in the RFQ from customers Bid of manufactures must be delivered on the due date specified in the RFQ Bid prices of manufactures must be below or equal to the reserve price specified by the customer in the RFQ If a RFQ was sent by a customer to a manufacture, all others manufactures have to receive RFQs too –Laws between Suppliers and Customers cannot be addressed because interactions are not allowed (organizations’ laws)

Carolina Howard Felicíssimo © LES/PUC-Rio

Environmets’ Laws Organizations’ Laws Roles’ Laws Interactions’ Laws Legend:

Carolina Howard Felicíssimo © LES/PUC-Rio Environmets’ Laws Organizations’ Laws Roles’ Laws Interactions’ Laws Legend:

Carolina Howard Felicíssimo © LES/PUC-Rio Case Study - Implementation Tac Ontology (tac.owl) Tac Rules (tac.rules) –Automation of part of the laws’ definitions –Check consistency among laws tac.owltac.rules + Java Programming + INFERENCE Results tac.owl Java Programming Results

Carolina Howard Felicíssimo © LES/PUC-Rio Related Work Enforcement is done based on Interactions’ Laws –XMLaw –LGI –Electronic Institutions How to reason with incomplete information and conflits? –Description Defesiable Logic OMINI...

Carolina Howard Felicíssimo © LES/PUC-Rio Conclusion An approach to regulate open MAS based on ontologies was defined A formal support for agents to base their behavior according to norms and to reason about action selection was provided The independent-domain ontology can be extended and it needs to be instantiated for specific domains Environments’ laws, Organizations’ laws, Roles’ laws and Interactions’ laws can be specified As a future work, the formalism(s) to be used will be chosen and the trade-offs about the choice will be identified

Questions ?