In this paper we advocate the use of multi-dimensional modal logics as a framework for knowledge representation and, in particular, for representing spatiotemporal information. We construct a two-dimensional logic capable of describing topological relationships that change over time. This logic, called PSTL (Propositional Spatio-Temporal Logic) is the Cartesian product of the well-known temporal logic PTL and the modal logic S4u , which is the Lewis system S4 augmented with the universal modality. Although it is an open problem whether the full PSTL is decidable, we show that it contains decidable fragments into which various temporal extensions (both point-based and interval based) of the spatial logic RCC-8 can be embedded. We consider known decidability and complexity results that are relevant to computation with muli-dimensional formalisms and discuss possible directions for further research.

Command and Control for coordinated response to domestic terrorist attack will require the ability of federal, state, and local agencies to maintain awareness of the status, capabilities, requirements, response plans, and C2 procedures, etc. of the other collaborating organizations. While progress is being made in improving information sharing, the TOPOFF exercises have demonstrated that organizations still lack any substantial ability to coordinate responses to large scale events that involve dozens of local, state, and federal organizations. In this paper we describe progress made in the development of new information access services that provide for improved situation awareness. We have strived to develop a solution that enables User Defined Operational Picture (UDOP) functionality while respecting the unique information management practices of the collaborating Homeland Security organizations. Our system concept, Vista, employs an adaptive machine learning paradigm that supports a new form of context-sensitive information access, monitoring, and alerting that fills substantial gaps in existing Crisis Information Management System technologies. Experimental results demonstrate very substantial improvements in information access efficiency and provide strong evidence for the feasibility of the overall concept. 1

Scientific discourse leaves implicit a vast amount of knowledge, assumes that this background knowledge is taken into account—even taken for granted—and treated as undisputed. In particular, the terminology in the empirical sciences is treated as antecedently understood. The background knowledge surrounding a theory is usually assumed to be true or approximately true. This is in sharp contrast with logic, which explicitly ignores underlying presuppositions and assumes uninterpreted languages. We discuss the problems that background knowledge may cause for the formalization of scientific theories. In particular, we will show how some of these problems can be addressed in the context of the computational representation of scientific theories.