In this paper the author describes a formal language for communication based on linguistics—more specifically, a theory of natural language communication and models of natural language conversations. The language has a small number of general message types which are formally defined by their intended effects on the recipient. For each message type he defines a standard, automated method of responding that depends only on the message type and is independent of the message’s content. For more complex conversations he provides methods for responding that do depend on the content. In this system, a message’s sender—automated or human—constructs and sends a message knowing that he cannot know, but can only predict, how it will be interpreted. The agent receiving the message interprets it and then uses it as a basis for inferring how it should respond. The message interpretation mechanism for this language is reusable, modular and shared by all applications. The benefit of this communication system is that it makes the communication infrastructure more flexible, easier to modify, easier to expand, and more capable. 1

In this paper we propose a number of extensions for object-oriented models in order to describe dynamic aspects of applications. These extensions enable the specification of objects that modify their behavior dynamically and the control of the dynamic evolution of objects by means of constraints expressed in the language of propositional temporal logic. We shall point out what differentiates our proposal from existing models and give examples to illustrate our arguments. We also present an algorithm for verifying consistency of specifications and which is suitable for an eventual implementation of our extensions. 1. Introduction The principal aim in designing a data model is to have a tool with which one can adequately describe some part of the world. By "adequately" we mean that the model provides the designer with a necessary and sufficient set of abstractions for easily and faithfully capturing the relevant properties of the problem of interest while irrelevant ones can be neglecte...

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