Graphic modeling in Distributed Autonomous and Asynchronous Automata (DA3)

Automated verification of distributed systems becomes very important in distributed computing. The graphical insight into the system in the early and late stages of the project is essential. In the design phase, the visual input helps to articulate the collaborative distributed components clearly. The formal verification gives evidence of correctness or malfunction, but in the latter case, graphical simulation of counterexample helps for better understanding design errors. For these purposes, we invented Distributed Autonomous and Asynchronous Automata (DA3), which have the same semantics as the formal verification base—Integrated Model of Distributed Systems (IMDS). The IMDS model reflects the natural characteristics of distributed systems: unicasting, locality, autonomy, and asynchrony. Distributed automata have all of these features because they share the same semantics as IMDS. In formalism, the unified system definition has two views: the server view of the cooperating distributed nodes and the agent view of the migrating agents performing distributed computations. The automata have two formally equivalent forms that reflect two views: Server DA3 for observing servers exchanging messages, and Agent DA3 for tracking agents, which visit individual servers in their progress of distributed calculations. We present the DA3 formulation based on the IMDS formalism and their application to design and verify distributed systems in the Dedan environment. DA3 formalism is compared with other concepts of distributed automata known from the literature.

Modelling Distributed Systems in Distributed Autonomous and Asynchronous Automata (DA3)

Integrated Model of Distributed Systems is used for modeling and verification. In formalism, the distributed system is modeled as a collection of server states and agent messages. The evolution of the system takes the form of actions that transform the global system configuration (states and messages) into a new configuration. Formalism is used in the Dedan verification environment for finding different kinds of deadlocks: communication deadlocks in the server view and resource deadlocks in the agent view. For other purposes, a conversion has been developed to equivalent models: to Petri nets for structural analysis and do Distributed Autonomous and Asynchronous Automata (DA3) for easy graphical modeling in terms of system components. In addition, it is possible to simulate a verified system on distributed components in DA3. The automata have two forms: Server-DA3 (S-DA3) for the server view and Agent-DA3 (A-DA3) for the agent view. DA3 formalism is compared to other concepts of distributed automata known from the literature.

Complexity of the characteristic semi-groups the direct products of „AG“ asynchronous automata of the strongly connected determined analogs the extensions associated with DFASC2 isomorfisms

The paper presents the assumption and the evidence is carried out of the direct product complexity of character-istic semi-groups of any number (“ ”) of deterministic, finite, asynchronous, highly consistent DFASC2. automata. The characteristic semi-group of the automaton interferes in the computational algorithm of the generalized homoeo-morphism of the automatons. Then determination the com-plexity of the characteristic semi-group enables to estimate the complexity of the computational generalized homoeo-morphism for the other classes of automatons. In the range of the mathematical model the conception of the determined analog of the extension of the automaton associated with the isomorphism g0, g1 ,…, gq-1 where q is the grade of the extensions, with the suitable assumptions it simulates the automaton variable in time. The variable automaton in time is the adequate mathematical model for the many technical and computational processes of the real time. The direct product of automatons can be considered as the realization- parallel calculations accordingly

Generalized Asynchronous Systems

The paper consider a mathematical model of a concurrent system, the special case of which is an asynchronous system. Distributed asynchronous automata are introduced here. It is proved that Petri nets and transition systems with independence can be considered as distributed asynchronous automata. Time distributed asynchronous automata are defined in a standard way by correspondence which relates events with time intervals. It is proved that the time distributed asynchronous automata generalize time Petri nets and asynchronous systems.