Steven Shapiro

Iterated belief change in the situation calculus

John McCarthys situation calculus has left an enduring mark on artificial intelligence research. This simple yet elegant formalism for modelling and reasoning about dynamic systems is still in common use more than forty years since it was first proposed. The ability to reason about action and change has long been considered a necessary component for any intelligent system. The situation calculus and its numerous extensions as well as the many competing proposals that it has inspired deal with this problem to some extent. In this paper, we offer a new approach to belief change associated with performing actions that addresses some of the shortcomings of these approaches. In particular, our approach is based on a well-developed theory of action in the situation calculus extended to deal with belief. Moreover, by augmenting this approach with a notion of plausibility over situations, our account handles nested belief, belief introspection, mistaken belief, and handles belief revision and belief update together with iterated belief change.

The cognitive agents specification language and verification environment for multiagent systems

The Cognitive Agents Specification Language (CASL) is a frame-work for specifying multiagent systems. It has a mix of declarative and procedural components to facilitate the specification and verification of complex multiagent systems. In this paper, we describe CASL and a verification environment (CASLve) for it based on the PVS verification system. We give an example of a multiagent meeting scheduler application specified with CASL. To illustrate the verification system, we discuss a proof we carried out in it, namely, that all bounded-loop CASL specifications terminate.

Specifying communicative multi-agent systems

In this paper, we describe a framework for specifying communicative multi-agent systems, using a theory of action based on the situation calculus to describe the effects of actions on the world and on the mental states of agents; and the concurrent, logic programming language ConGolog to specify the actions performed by each agent. Since ConGolog has a well-defined semantics, the specifications can be used to reason about the behavior of individual agents and the system as a whole. We extend the work presented in [7] to allow the specifications to mention agents’ goals explicitly. The framework presented here allows the behavior of different agents to be specified at different levels of abstraction, using a rich set of programming language constructs. As an example, we specify a meeting scheduler multi-agent system.

Modeling Multiagent Systems with CASL - A Feature Interaction Resolution Application

In this paper,we describe the CognitiveAgents Specification Language (CASL), and exhibit its characteristics by using it to model the multiagent feature interaction resolution system described by Griffeth andVelthuijsen [7]. We discuss the main features of CASL that make it a useful language for specifying and verifying multiagent systems. CASL has a nice mix of declarative and procedural elements with a formal semantics to facilitate the verification of properties of CASL specifications.

Combining RFID with Ontologies to Create Smart Objects

Radio frequency identification (RFID) technology has long been known for its ability to uniquely identify objects. Recent years have witnessed a significant increase in storage capacity on the tag, which is giving rise to a new set of application scenarios. As the tag itself can carry relevant context information, processes can be managed locally rather than relying on a centralised system infrastructure. This in turn results in a massive interoperability challenge. We propose to solve this problem by combining RFID technology with ontologies to create smart objects in the context of manufacturing process control. The idea is to store information originating from an SAP ERP system using the PSL Ontology (ISO 18629) for representing processes and time directly on the RFID tags. As an item flows through a manufacturing process, information about the item can be stored on its tag. This information, along with the PSL axioms, can be used to make inferences about the manufacturing process and the item in particular. In this paper, we discuss our formalisation of an ontology for the SAP data model and show an example of translating data from an SAP ERP system into PSL axioms, and answering queries about a manufacturing process.

Goal Change in the Situation Calculus

Although there has been much discussion of belief change (e.g. [4, 21]), goal change has not received much attention. In this paper, we propose a method for goal change in the framework of Reiters; [12] theory of action in the situation calculus [8, 10], and investigate its properties. We extend the framework developed by Shapiro et al. [17] and Shapiro and Lesperance [16], where goals and goal expansion were modelled, but goal contraction was not.

The Cognitive Agents Specification Language and Verification Environment

The Cognitive Agents Specification Language (CASL) is a framework for specifying multiagent systems. It has a mix of declarative and procedural components to facilitate the specification and verification of complex multiagent systems. In this chapter, we describe CASL and a verification environment (CASLve) for it based on the PVS verification system. We give an example of a multiagent meeting scheduler application specified with CASL. To illustrate the verification system, we discuss a proof we carried out in it, namely, that all bounded-loop CASL specifications terminate.