Due to the huge amount of multi-source news that are available on the Web at any time, it is crucial to provide intelligent mechanisms to select and rank news reports. Over the last few years, a number of approaches based on criteria such as freshness, relevance and viewer profile have been proposed. However, most existing news processing services do not deal with credibility from a qualitative perspective, and do not provide mechanisms to cope with controversial news reports. To fill this gap, this paper proposes a news service framework that brings the notions of trust and pluralism into play. The proposed framework is based on a set of basic postulates characterizing the nature of trust. In our proposal, trust is modeled using Defeasible Logic Programming, a general-purpose defeasible argumentation formalism based on logic programming. Our approach helps identify antagonism among sources of news and facilitates the analysis of opposing positions. This allows us to integrate dialectical reasoning into a news recommender system, which has the capability of providing a reasoned basis for the news presented to the viewer.Red de Universidades con Carreras en Informática (RedUNCI
