Integration of Heterogeneous Knowledge Sources in the CALO Query Manager

Abstract

Abstract. We report on our experience in developing a query answering system that integrates multiple knowledge sources. The system is based on a novel architecture for combining knowledge sources in which the sources can produce new subgoals as well as ground facts in the search for answers to existing subgoals. The system uses a query planner that takes into account different query processing capabilities of individual sources and augments them gracefully. A reusable ontology provides a mediated schema that serves as the basis for integration. We have evaluated the system on a suite of test queries in a realistic application to verify the practicality of our approach.

Efficiently ordering subgoals with access constraints

“…We will refer to each gi(Xi) as a subgoal in the rule. 1 In this paper we assume that all rules are safe, i.e., all variables appearing in the head of the rule also appear in some subgoal in the rule body.…”

“…Query evaluation using views is one instance in which grouping constraints are useful [13,6]. Such constraints also often arise in integration of heterogeneous knowledge and reasoning systems [2,1]. We show how to adapt our algorithm to handle grouping constraints, albeit the algorithm now runs in time quadratic in the size of the query.…”

Scaffolding a Methodology for Situating Cognitive Technology Within Everyday Contexts

“…Technological artefacts such as intelligent personal assistants are increasingly employed within everyday contexts. Systems such as CALO [1] and its popular spin-off Siri accompany users throughout their daily lives, supporting a wide array of leisure activities and professional obligations. Consequently, they have to operate across a broad range of diverse, hardly predictable and sometimes chaotic contexts.…”