British Columbia Institute of Technology

About: British Columbia Institute of Technology is a education organization based out in Burnaby, British Columbia, Canada. It is known for research contribution in the topics: Smart grid & Belief revision. The organization has 458 authors who have published 785 publications receiving 16140 citations.

Ranking Functions for Belief Change

Abstract: In this paper, we explore the use of ranking functions in reasoning about belief change. It is well-known that the semantics of AGM belief revision can be defined either through total pre-orders or through ranking functions over interpretations. While both approaches have generally been seen as equivalent with respect to single-shot belief revision, we argue that ranking functions provide distinct advantages at both the theoretical level and the practical level. We demonstrate belief revision induces a natural algebra over ranking functions, which treats belief states and observations in the same manner. Moreover, when we introduce belief progression due to actions, we demonstrate that many natural domains can be easily represented with suitable ranking functions. We support our position through formal results, as well as a series of natural problems in commonsense reasoning. We conclude with a discussion of aggregate functions for combining rankings, as well as potential future applications in counterfactual reasoning.

A logical approach to promoting trust over knowledge to trust over action

Abstract: We discuss two related forms of trust. One form of trust is related to the perceived knowledge of other agents; we accept the information that another agent provides if we believe they have sufficient expertise in a particular domain. The second form is related to action; we trust another agent to act on our behalf if we believe they will choose acceptable actions. In this paper, we explore the relationship between these two forms of trust. In particular, we use an existing model of trust to demonstrate how trust over knowledge can determine when trust over actions is appropriate. We take a formal approach to this problem, using logic-based tools for representing and reasoning about actions and beliefs to characterize trust over action. While our primary aim is to develop a formal methodology that permits trust over actions to be defined in terms of trust over knowledge, we also consider applications that are both practical and speculative. On the practical side, we consider how our methods can be used to reason about trusted third parties in communication protocols. On the speculative side, we suggest that models of trust have a role to play in the development of ethical decision-making agents.

Belief Revision and Trust

Abstract: Belief revision is the process in which an agent incorporates a new piece of information together with a pre-existing set of beliefs. When the new information comes in the form of a report from another agent, then it is clear that we must first determine whether or not that agent should be trusted. In this paper, we provide a formal approach to modeling trust as a pre-processing step before belief revision. We emphasize that trust is not simply a relation between agents; the trust that one agent has in another is often restricted to a particular domain of expertise. We demonstrate that this form of trust can be captured by associating a state-partition with each agent, then relativizing all reports to this state partition before performing belief revision. In this manner, we incorporate only the part of a report that falls under the perceived domain of expertise of the reporting agent. Unfortunately, state partitions based on expertise do not allow us to compare the relative strength of trust held with respect to different agents. To address this problem, we introduce pseudometrics over states to represent differing degrees of trust. This allows us to incorporate simultaneous reports from multiple agents in a way that ensures the most trusted reports will be believed.

Ultrasound Examination of the Painful Shoulder

Abstract: Ultrasonic examinations of the shoulders of 20 patients were undertaken. Eight were asymptomatic volunteers, and the remaining 12 had clinical signs of rotator cuff tears. The patients with painful shoulders were further evaluated with arthrography. The results of these two tests were then correlated. Although a correlation of 75% was found between the ultrasonographic and angiographic examinations, in cases where the area of the cuff tear could be adequately visualized with ultrasound, correlation rose to 90%.

Technology, values and sustainable development

Abstract: The use of technology is often decoupled from community values and broader questions of individual and collective purpose. How then can individuals and communities be empowered to make meaningful choices about technology? How do we move from being passive technological users or subjects to active agents in constructively shaping patterns of technological development? It is argued that informed technological decision-making, especially participatory practice, lies at the heart of building “resilient communities.”