Model Checking of Stream Processing Pipelines

Event stream processing (ESP) is the application of a computation to a set of input sequences of arbitrary data objects, called "events", in order to produce other sequences of data objects. In recent years, a large number of ESP systems have been developed; however, none of them is easily amenable to a formal verification of properties on their execution. In this paper, we show how stream processing pipelines built with an existing ESP library called BeepBeep 3 can be exported as a Kripke structure for the NuXmv model checker. This makes it possible to formally verify properties on these pipelines, and opens the way to the use of such pipelines directly within a model checker as an extension of its specification language

Efficient Symbolic Supervisory Synthesis and Guard Generation: Evaluating partitioning techniques for the state-space exploration

The supervisory control theory (SCT) is a model-based framework, which automatically synthesizes a supervisor that restricts a plant to be controlled based on specifications to be fulfilled. Two main problems, typically encountered in industrial applications, prevent SCT from having a major breakthrough. First, the supervisor which is synthesized automatically from the given plant and specification models might be incomprehensible to the users. To tackle this problem, an approach was recently presented to extract compact propositional formulae (guards) from the supervisor, represented symbolically by binary decision diagrams (BDD). These guards are then attached to the original models, which results in a modular and comprehensible representation of the supervisor. However, this approach, which computes the supervisor symbolically in the conjunctive way, might lead to another problem: the state-space explosion, because of the large number of intermediate BDD nodes during computation. To alleviate this problem, we introduce in this paper an alternative approach that is based on the disjunctive partitioning technique, including a set of selection heuristics. Then this approach is adapted to the guard generation procedure. Finally, the efficiency of the presented approach is demonstrated on a set of benchmark examples

A verification study based on the CTP model

Master'sMASTER OF SCIENC

Automatic generation of protocol converters from scenario-based specifications

Master'sMASTER OF SCIENC

28th International Symposium on Temporal Representation and Reasoning (TIME 2021)

The 28th International Symposium on Temporal Representation and Reasoning (TIME 2021) was planned to take place in Klagenfurt, Austria, but had to move to an online conference due to the insecurities and restrictions caused by the pandemic. Since its frst edition in 1994, TIME Symposium is quite unique in the panorama of the scientifc conferences as its main goal is to bring together researchers from distinct research areas involving the management and representation of temporal data as well as the reasoning about temporal aspects of information. Moreover, TIME Symposium aims to bridge theoretical and applied research, as well as to serve as an interdisciplinary forum for exchange among researchers from the areas of artifcial intelligence, database management, logic and verifcation, and beyond

Complementary formalisms - synthesis, verification and visualization

Ph.DDOCTOR OF PHILOSOPH

Communicating transaction processes

Message Sequence Charts (MSCs) are an attractive vi-sual formalism which are used in the early design stages of reactive systems. They portray scenarios that arise fromcomponent interactions and hence can be used to capture requirements and test cases. MSCs and a related mecha-nism called HMSCs (High-level Message Sequence Charts) have been standardized [15] for specifying telecommunica-tion software. A version of MSC called Sequence Diagram is a behavioral diagram type used in UML [6].In all these settings, MSCs are used to capture system requirements. To move towards an implementation, one mustobtain an executable specification which is related in som

Communicating Transaction Processes

Message Sequence Charts (MSC) have been traditionally used to depict execution scenarios in the early stages of design cycle. MSCs portray inter-process ( inter-object) interactions. Synthesizing intra-process (intra-object) executable specifications from an MSC-based description is a non-trivial task. Here we present a model called Communicating Transaction Processes (CTP) based on MSCs from which an executable specification can be extracted in a straightforward manner. Our model describes a network of communicating processes as a collection of highlevel labeled transition systems, where processes interact via common action labels. Each action is a non-atomic interaction which is described by a guarded choice of MSCs. Thus our model achieves a separation of concerns: the high-level transition systems depicting intra-process control flow, while the actions in the transition system capture interprocess interaction via MSCs. We show how to extract an ordinary Petri net from a CTP model thereby leading to a standard operational semantics. We also discuss the connection of our formalism to Live Sequence Charts, an extension of MSCs which also has an executable semantics

Designing communicating transaction processes by supervisory control theory

10.1007/s10703-006-0023-0Formal Methods in System Design302117-141FMSD