On Situations and the World: A Problem for Barwise and Etchemendy

2010

Information and Architecture 147 DAVID ISRAEL AND JOHN PERRY 8 Doxic Paradox: A Situational Solution 161 ROBERT C. KOONS 9 CLP (APA): Coinductive SemantiGS of Horn Clauses with Compact Constraints 179 KUNIAKI MUKAI 10 Inferring in a Situation about Situations 215 HlDEYUKI NAKASHIMA AND SYUN TUTIYA V vi / CONTENTS Situation-Theoretic Aspects of Databases BILL ROUNDS

2005 7th International Conference on Information Fusion, 2005

The aim of this paper is to present recent works made in the study of distributed systems and knowledge-based programs and show how these results can contribute to the formalization of the Situation Analysis (SA) problem. Precisely, we propose to use the algebraic concepts detailed in a recent book of Fagin, Halpern, Moses and Vardi as a blueprint for SA system design. In this paper we show how the formal model in question can be used to handle and distinguish numerical evaluations of probabilities and belief as well as means to represent and reason on knowledge. After a presentation of key models and concepts of Situation Awareness (SAW) and SA we proceed with a brief review of formal models recently used and associated published work. Building upon Fagin and Halpern's work but also on Bundy's which extend the probability structure proposed by Nilsson this paper shows how to translate the basic concepts of functional SA models in the proposed formal algebraic framework. The algebraic concepts exposed and studied herein are those of agents and environment, local and global states, temporal sequences of global states called runs, systems or sets of runs, actions, protocols and finally contexts.

To appear in the forthcoming volume "Trends in Logic" edited by Baltag and Smets

We recall a largely forgotten intellectual project: that of providing a formal theory of situations that does justice to informal ideas about situations and informa- tion flow with the ‘situation theory’ community of the late 1980s and early 1990s. Instead of defending specific desiderata, and in the spirit of Barwise’s ‘Branch Points’, we record some the difficulties that defined the project by posing a se- ries of twelve questions. Drawing on the theory of channels and information flow (Barwise and Seligman, late 1990s), with some modifications and extensions, we provide a version of situation theory that answers some of these questions. One of the main extensions is to allow probabilistic constraints. We also consider a more recent proposal by van Benthem to capture many of situation theory’s insights using a modal logic closely related to dependancy logic and use this as an alternative but comparable way of answering our questions.

Situation Theory originated as an attempt to provide mathematical foundations for Situation Semantics, a research programme initiated by Jon Barwise and John Perry in the 1980s. It developed into a general theory of information. This chapter provides a systematic development of Situation Theory, using an account of `structural relations', based on Peter Aczel's pioneering work in non-well-founded set theory. It starts with the question of how to represent Situation-Theory-style information in a standard relational structure, and goes on to articulate a theory of structural relations, and uses this to address various topics such as circularity, argument roles, partiality, substitution and abstraction. The final section addresses truth and logic in Situation Theory, and the concept of internal definability.

Philosophical Studies, 1985

Theoretical Aspects of Reasoning About Knowledge, 1994

2009

Logics that involve collections (sets, multisets), and cardinality constraints are useful for reasoning about unbounded data structures and concurrent processes. To make such logics more useful in verification this paper extends them with the ability to compute direct and inverse relation and function images. We establish decidability and complexity bounds for the extended logics.

2012 IEEE International Multi-Disciplinary Conference on Cognitive Methods in Situation Awareness and Decision Support, 2012

One of the most substantial advantages that human analysts have over machine algorithms is the ability to seamlessly integrate sensed data into a situation-based internal narrative. Replicating an analogous internal representation algorithmically has proved to be a challenging problem that is the focus of much current research. For a machine to more accurately make complex decisions over a stable, consistent and useful representation, situations must be inferred from prior experience and corroborated by incoming data. We believe that a common mathematical framework for situations that addresses varying levels of complexity and uncertainty is essential to meeting this goal. In this paper, we present work in progress on developing the mathematics for probabilistic situations.

Annals of Pure and Applied Logic, 2004

The paper proposes a logical model of combinatorial problems; it also gives an example of a problem of the class NP that cannot be solved in polynomial time on the dimension of the problem.