[TMP-104] Reasoning on Contextual Hierarchies via Answer Set Programming with Algebraic Measures

Contact person: Loris Bozzato 

Internal Partners:

1. Fondazione Bruno Kessler (FBK), Loris Bozzato
2. TU Wien, Thomas EIter

 

This project continues the collaboration between FBK and TUW about defeasible knowledge in description logics in the Contextualized Knowledge Repository (CKR) framework.In applications, knowledge can hold by default and be overridden in more specific contexts. For example, in a tourism event recommendation system, events can appear as suggested to a class of tourists in a general context: in the more specific context of a particular tourist, preferences can be refined to more precise interests, which may override those at higher contexts.Goal of this project is to enhance the answer set programming (ASP) based realization of CKR to deal with complex context hierarchies: we use an ASP extension recently proposed by TUW, ASP with algebraic measures, which allows for reasoning on orderings induced by the organization of defeasible knowledge. This collaboration provides a prototype for reasoning over CKR hierarchies, but also an application for ASP with algebraic measures.

Results Summary

The goal of this project is to reason on complex contextualized knowledge bases using an answer set programming extension with algebraic measures and show the capabilities of this formalism.

The main formal contributions of this project are:

• an extension of the CKR contextual framework to reason about defeasible information over multi-relational contextual hierarchies.
• an ASP based modelling of multi-relational CKRs, where combination of model preferences is realized via algebraic measure expressions.
• an aspirin based implementation of query answering in a fragment of multi-relational CKRs, extending the existing CKR datalog translation.
• a study of further capabilities of algebraic measures, showing the possibilities for reasoning on model aggregation.

Tangible Outcomes

1. Program/code: Prototype – Loris Bozzato https://github.com/dkmfbk/ckrew/releases/tag/v.1.6 
2. Technical report
   https://tinyurl.com/FBK-TUW-MP-Report
3. Video presentation summarizing the project