A context-based institutional normative environment

We explore the concept of an agent-based Electronic Institution including a normative environment that supports electronic contract formation by providing a contextual normative background. We formalize the normative state using first-order logic and define institutional rules and norms operating on that state. A suitable semantics regarding the use of norms within a hierarchical context structure is given, based on norm activation conflict and defeasibility. Norm activation relies on substitution as in first-order logic. Reasoning about the fulfillment and violation of deadline obligations is formalized using linear temporal logic; implementation with institutional rules is discussed. Examples exploiting the normative environment are given. © Springer-Verlag Berlin Heidelberg 2009

Comparing Defeasible Argumentation and Non-Monotonic Fuzzy Reasoning Methods for a Computational Trust Problem with Wikipedia

Computational trust is an ever-more present issue with the surge in autonomous agent development. Represented as a defeasible phenomenon, problems associated with computational trust may be solved by the appropriate reasoning methods. This paper compares two types of such methods, Defeasible Argumentation and Non-Monotonic Fuzzy Logic to assess which is more effective at solving a computational trust problem centred around Wikipedia editors. Through the application of these methods with real-data and a set of knowledge-bases, it was found that the Fuzzy Logic approach was statistically significantly better than the Argumentation approach in its inferential capacity

Electronic institutions with normative environments for agent-based E-contracting

Tese de doutoramento. Engenharia Informática. Faculdade de Engenharia. Universidade do Porto. 201