This is the first in a series of papers extending the Abstract State Machine Thesis — that arbitrary algorithms are behaviorally equivalent to abstract state machines — to algorithms that can interact with their environments during a step rather than only between steps. In the present paper, we describe, by means of suitable postulates, those interactive algorithms that (1) proceed in discrete, global steps, (2) perform only a bounded amount of work in each step, (3) use only such information from the environment as can be regarded as answers to queries, and (4) never complete a step until all queries from that step have been answered. We indicate how a great many sorts of interaction meet these requirements. We also discuss in detail the structure of queries and replies and the appropriate definition of equivalence of algorithms. Finally, motivated by our considerations concerning queries, we discuss a generalization of first-order logic in which the arguments of function and relation symbols are not merely tuples of elements but orbits of such tuples under groups of permutations of the argument places.

. Persistent Turing Machines (PTMs) are multitape machines with a persistent worktape preserved between interactions, whose inputs and outputs are dynamically generated streams of tokens (strings). They are a minimal extension of Turing Machines (TMs) that express interactive behavior. They provide a natural model for sequential interactive computation such as single-user databases and intelligent agents. PTM behavior is characterized observationally, by input-output streams; the notions of equivalence and expressiveness for PTMs are defined relative to its behavior. Four different models of PTM behavior are examined: language-based, automaton-based, function-based, and environment-based. A number of special subclasses of PTMs are identified; several expressiveness results are obtained, both for the general class of all PTMs and for the special subclasses, proving the conjecture in [We2] that interactive computing devices are more expressive than TMs. The methods and tool...

We present Persistent Turing Machines (PTMs), a new way of interpreting Turing-machine computation, one that is both interactive and persistent. A PTM repeatedly receives an input token from the environment, computes for a while, and then outputs the result. Moreover, it can \remember" its previous state (work-tape contents) upon commencing a new computation. We show that the class of PTMs is isomorphic to a very general class of eective transition systems, thereby allowing one to view PTMs as transition systems \in disguise." The persistent stream language (PSL) of a PTM is a coinductively dened set of interaction streams : innite sequences of pairs of the form (w i ; w o ), recording, for each interaction with the environment, the input token received by the PTM and the corresponding output token. We dene an innite hierarchy of successively ner equivalences for PTMs over nite interaction-stream prexes and show that the limit of this hierarchy does not coincide with PSL-equivalence. The presence of this \gap" can be attributed to the fact that the transition systems corresponding to PTM computations naturally exhibit unbounded nondeterminism. We also consider amnesic PTMs, where each new computation begins with a blank work tape, and a corresponding notion of equivalence based on amnesic stream languages (ASLs). We show that the class of ASLs is strictly contained in the class of PSLs. Amnesic stream languages are representative of the classical view of Turing-machine computation. One may consequently conclude that, in a stream-based setting, the extension of the Turing-machine model with persistence is a nontrivial one, and provides a formal foundation for reasoning about programming concepts such as objects with static elds. We additional...

Database driven Information Systems (IS) have two distinct integrity concerns: static,ordata integrity and dynamic integrity. Static integrity addresses situations within a particular database state,orinstance and dynamic integrity is concerned with state sequences instead.

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Channel sensitivity in reactive systems arises when the system interacts over multiple interaction channels simultaneously and it is important to distinguish between the many channels. While the design and verification of reactive systems is complex and not amenable to traditional paradigms of inductive reasoning, channel sensitivity adds an additional dimension of complexity. In this paper, we provide an introduction to channel sensitivity and look into the kinds of translational mismatches that could occur in designing a channel sensitive model from a set of functionality specifications.

Information systems design concern modeling systems that are dynamic in nature. A dynamic system essentially has two dimensions of concern -- static structure and dynamic behavior. The existence of dynamics -- or interactions among parts of the system distinguish a dynamic system from a heap or collection of parts. Specification and management of the static aspects of an information system like the data and metadata have been fairly well addressed by existing paradigms. However an understanding of the dynamic nature of information systems is still low. Currently most paradigms model behavioral properties above an existing structural model, resulting in what may be called "entity centric" modeling. Such a kind of modeling would neglect properties that can be attributed to behavioral processes themselves, and relationships that might exist among such processes. In this paper, we address behavioral modeling by first considering system behavior to be in the form of an abstract "interaction...

Information systems' (IS) design concerns modeling systems that are dynamic in nature. A dynamic system essentially has two dimensions of concern -- static structure and dynamic behavior. The existence of dynamics -- or interactions among parts of the system distinguish a dynamic system from a heap or collection of parts. Specification and management of the static aspects of an information system like the data and metadata have been fairly well addressed by existing paradigms. However, an understanding of the dynamic nature of information systems is still low. Currently most paradigms model behavioral properties above an existing structural model, resulting in what may be called "entity centric" modeling. Such a kind of modeling would neglect properties that can be attributed to behavioral processes themselves, and relationships that might exist among such processes. This thesis argues that the dynamics of an information system are best managed by explicitly characterizing...

Abstract. Situated design agents are agents built using concepts from situated cognition. As situated design agents are constructive and

Tasks like supply chain management, design of interorganizational workflow and design of virtual organizations or consortia, require mechanisms to analyze interaction requirements spanning across autonomous organizations. While existing means of analysis would help in identifying pertinent actors and interactions among them, properties which could manifest by virtue of the interactions themselves may go undetected. In this paper, we present an approach that looks for properties of a given problem domain which manifest due to the interactions that take place in the domain. We use data mining to look for knowledge from a set of transaction data collected from past transactions that have taken place. A specific kind of problem is considered involving interactions among a set of autonomous actors, and an interaction model is built based on the results of the data mining process. Keywords: Coordination, Interaction Properties, Data Mining, Modeling Interactive Behavior. This d...