Abstract. Many techniques used for discovering faults and vulnerabilities in distributed systems and services require as inputs formal behavioral models of the systems under validation. Such models are traditionally written by hand, according to the specifications which are known, leading to a gap between the real systems which have to be validated and their abstract models. A method to bridge this gap is to develop tools that automatically extract the models directly from the implementations of distributed systems and services. We propose here a general model extraction solution, applicable to several service technologies. At the core of our solution we develop a method for transforming the control flow graph of an abstract communicating system into its corresponding behavioral model represented as an Extended Finite State Machine. We then illustrate our method for extracting models from services implemented using different concrete technologies such as Java RMI, Web services and HTTP Web applications and servlets.

Abstract:Formal behavioral models of software services are used as input by analysis tools which check their properties on hand of the given models. However, there is a gap between the real systems which have to be validated and their abstract models. This work proposes to bridge this gap by tools which extract behavioral models from software services implementations. The method proposed here aims at ensuring a general solution, applicable to several service technologies. The core of this solution consists of transforming the control flow graph of a communicating system into its corresponding behavioral model represented as an EFSM (Extended Finite State Machine). The extracted EFSM model can be automatically translated into an entity description in a formal security specification language for distributed systems. This will enable the use of formal analysis tools for real service implementations.

Absrrucr: The PLCs are now more flexible and powerhl due to their network operation. The paper deals the communication in a hybrid decentralized PLC system. The system operates as a bi-directional communication system based on a serial port RS-232 each element receiving and sending ASCII telegrams. A program was designed and implemented for testing the Communication in the system. For each PLC the test program was written in his own pro,g"ming language. The system includes also a MMI element, the Operator Station that is shared by the PLCs. The written test program and test program and specific routines can be used when operating in a hybrid PLC system, not having, as usual, a specific communication protocol.