ONTrust: A Reference Ontology of Trust
Glenda Amaral, Tiago Prince Sales, Riccardo Baratella, Daniele Porello, Renata Guizzardi, Giancarlo Guizzardi
TL;DR
ONTrust provides a rigorously grounded reference ontology of trust, built on the Unified Foundational Ontology (UFO) and implemented in OntoUML to support interoperable modeling and reasoning about trust in humans, organizations, and machines. It formalizes multiple trust flavors (Ground, Social, Weak, Strong, Institution-based) and connects trust to risk through a dedicated ontological model, including a quantitative perspective with gradable trust measures and influence factors. The authors validate the ontology via Alloy-based model checking, introduce axioms to curb ill-formed instantiations, and demonstrate utility through two literature-based case studies (e-voting and AI medical diagnosis). The work advances trustworthy AI and governance of decentralized trust by enabling semantic interoperability and automated reasoning about trust dynamics, with future work on trust propagation.
Abstract
Trust has stood out more than ever in the light of recent innovations. Some examples are advances in artificial intelligence that make machines more and more humanlike, and the introduction of decentralized technologies (e.g. blockchains), which creates new forms of (decentralized) trust. These new developments have the potential to improve the provision of products and services, as well as to contribute to individual and collective well-being. However, their adoption depends largely on trust. In order to build trustworthy systems, along with defining laws, regulations and proper governance models for new forms of trust, it is necessary to properly conceptualize trust, so that it can be understood both by humans and machines. This paper is the culmination of a long-term research program of providing a solid ontological foundation on trust, by creating reference conceptual models to support information modeling, automated reasoning, information integration and semantic interoperability tasks. To address this, a Reference Ontology of Trust (ONTrust) was developed, grounded on the Unified Foundational Ontology and specified in OntoUML, which has been applied in several initiatives, to demonstrate, for example, how it can be used for conceptual modeling and enterprise architecture design, for language evaluation and (re)design, for trust management, for requirements engineering, and for trustworthy artificial intelligence (AI) in the context of affective Human-AI teaming. ONTrust formally characterizes the concept of trust and its different types, describes the different factors that can influence trust, as well as explains how risk emerges from trust relations. To illustrate the working of ONTrust, the ontology is applied to model two case studies extracted from the literature.