A defeasible logic programming-based framework to support argumentation in Semantic Web applications

Abstract

Using ontologies, the SemanticWeb provides structure and meaning to the vast amount of available information on the World WideWeb (WWW) and enables machines and/or computers to utilize, process, reason and discover knowledge from it. The logic layer of the Semantic Web stack provides a set of logic-based rule languages to perform automated reasoning over such information, produce results and assist the decision maker in the decision making process. Initial efforts in the literature for reasoning in Semantic Web applications have focused on the use of monotonic logic. However such efforts lack the capability to represent and reason when the underlying information is incomplete and/or contradictory.To overcome this problem, defeasible reasoning-based Semantic Web applications have been proposed that are capable of representing and reasoning over incomplete and/or contradictory information after defining the priorities between them. However their drawback is that they can only represent and reason over information coming from a single source. In scenarios where the decision maker is interested in considering information from multiple sources (such as information from collaborating enterprises or the feedback from customers) and where such information is incomplete and/or contradictory, current Semantic Web-based approaches do not provide any solution to represent, reason, resolve conflicts and integrate it to assist in the decision making process. This is in contrast to the approaches proposed in the literature in Artificial intelligence, where argumentation formalisms have been used to reason over contradictory information and produce a justifiable, tractable conclusion.Therefore, to overcome such limitations in the Semantic Web discussed above, in this thesis a generic defeasible logic programming-based framework is proposed to support argumentation in Semantic Web applications (GF@SWA). GF@SWA enables Semantic Web applications to represent both structured and unstructured information and/or translate the existing information into a defeasible logic programming (DeLP) format, perform hybrid reasoning for arguments construction, identify and resolve conflicts among arguments, integrate them and produce their graphical representation in the form of reasoning chains. The GF@SWA also provides a solution to integrate the reasoning chains produced by different Semantic Web applications and assists the decision maker in the decision making process. For validation and evaluation of GF@SWA, three Semantic Web applications are developed using GF@SWA to provide decision support to an enterprise to achieve business intelligence. The functionality and features of each Semantic Web application are validated and evaluated to highlight the effectiveness of GF@SWA in addressing the decision making requirements of an enterprise.