Sharif Digital Repository

Reo is an exogenous coordination language for synthesizing components participating in a component-based system. The notion of Bchi automaton over streams of records (BAR for short) is a proposed operational semantics for Reo that covers several aspects of coordination strategies such as synchronization, context dependencies and fairness constraints. In this paper and for the purpose of modeling real-time coordination systems specified by Reo, we present a timed version of BARs as the acceptors of timed streams of records. We show that timed BAR and its streams of records based semantics are more standard and also more expressive than timed constraint automaton which is the first proposed... 

To enable a relevance feedback paradigm to evolve itself by users' feedback, a reinforcement learning method is proposed. The feature space of the medical images is partitioned into positive and negative hypercubes by the system. Each hypercube constitutes an individual in a genetic algorithm infrastructure. The rules take recombination and mutation operators to make new rules for better exploring the feature space. The effectiveness of the rules is checked by a scoring method by which the ineffective rules will be omitted gradually and the effective ones survive. Our experiments on a set of 10,004 images from the IRMA database show that the proposed approach can better describe the semantic... 

Models of computation abstract away a number of implementation details in favor of well-defined semantics. While this has unquestionable benefits, we argue that analysis of models solely based on operational semantics (implementation oblivious analysis) is unfit to drive implementation design space exploration. Specifically, we study the tradeoff between buffer size and streaming throughput in applications modeled as synchronous data flow (SDF) graphs. We demonstrate the inherent inaccuracy of implementation-oblivious approach, which only considers SDF operational semantic. We propose a rigorous transformation, which equips the state of the art buffer-throughput tradeoff analysis technique... 

Models of computation abstract away a number of implementation details in favor of well-defined semantics. While this has unquestionable benefits, we argue that analysis of models solely based on operational semantics (implementationoblivious analysis) is unfit to drive implementation design space exploration. Specifically, we study the tradeoff between buffer size and streaming throughput in applications modeled as synchronous data flow (SDF) graphs. We demonstrate the inherent inaccuracy of implementationoblivious approach, which only considers SDF operational semantic. We propose a rigorous transformation, which equips the state of the art buffer-throughput tradeoff analysis technique... 

In this paper we develop a formal semantics of security protocols. Its main virtue is that it is a generic model, in the sense that it is parameterized over e.g. the intruder model. Further characteristics of the model are a straightforward handling of parallel execution of multiple protocols, locality of security claims, the binding of local constants to role instances, and explicitly defined initial intruder knowledge. We validate our framework by analyzing the Needham-Schroeder-Lowe protocol  

Constraint automata are the first-proposed operational semantics of Reo coordination language. They can be composed not only by all well-defined composition operators of labeled transition systems but also by two new operators. The new operators are joining of constraint automata with respect to their common port names and hiding a port name in all transition labels. The operations of these two extra operators depend on the internal structures of the transition labels, while in the others each transition label is considered as a simple entity. An equivalence relation between transition systems is a congruence relation if the replacement of the components of a model by the equivalent ones... 

Reo is a connector language for the exogenous composition and orchestration of components in a software system. An operational semantics of Reo connectors can be given in terms of Büchi automata over a suitable alphabet of records, capturing both synchronization and context dependency requirements. In this paper, we define an action based linear time temporal logic for expressing properties of Reo connectors. Formulas can be synthesized into Büchi automata representing Reo connectors, thus leading to an automata based model checking algorithm. By generalizing standard automata based model checking algorithms for linear time temporal logic, we give an efficient on-the-fly algorithm for the... 

Reo is an exogenous coordination language for synchronizing components participating in a component-based system. In this paper we provide a verification framework for model checking of Reo connectors. The proposed framework applies an extension of Büchi automata as the operational semantic model for Reo connectors and a record-based extension of linear time temporal logic (LTL) for expressing properties. Several aspects of Reo connectors, specially synchronization, context dependencies and fairness constraints, are addressed by this model checker due to its supported underlying model. The main ideas behind this implementation are to introduce a symbolic representation for the main elements... 

We present a process algebra for modeling and reasoning about Mobile Ad hoc Networks (MANETs) and their protocols. In our algebra we model the essential modeling concepts of ad hoc networks, i.e. local broadcast, connectivity of nodes and connectivity changes. Connectivity and connectivity changes are modeled implicitly in the semantics, which results in a more compact state space. Our connectivity model supports unidirectional links. A key feature of our algebra is eliminating connectivity information from the specification of a network, and transferring its complexity to the semantics. We give a formal operational semantics for our process algebra, and define equivalence relations on... 

Constraint automata have been proposed as the operational semantics of Reo, a glue-code language for the exogenous composition and orchestration of components in a software system. In this paper we recast the theory of constraint automata into that of Büchi automata on infinite strings of records. We use records to express simultaneity constraints of I/O operations and show that every constraint automaton can be expressed as a Büchi automaton on an appropriate alphabet of records. Further, we give examples of component compositions that are expressible as Büchi automata but not as constraint automata. Finally, we show that the join composition operator for constraint automata and its... 

Reo is an exogenous coordination language for compositional construction of the coordinating subsystem of a component-based software. Constraint automaton is defined as the operational semantics of Reo. The main goal of this work is to prepare a model checking based verification environment for component-based systems, which their component connectors are modeled by Reo networks and Constraint Automata. We use compositional minimization and abstraction methods of model checking for verification of component-based systems and their component connectors modeled by Reo