Osman Hasan’s research while affiliated with National University of Sciences and Technology and other places

Currently, Model-Driven Engineering (MDE) plays a key role in the software development process as it aims to handle their increasing complexity and focuses on the automatic generation of code and/or specifications from system models. This paper presents a very useful tool for the automatic generation of Maude specifications from both Petri net PNML (Petri Net Markup Language) descriptions or incidence matrices. At the end of this paper, a simple but complete Petri net example will be presented to demonstrate the usefulness of the developed tool.

Partial Differential Equations (PDEs) are widely used for modeling the physical phenomena and analyzing the dynamical behavior of many engineering and physical systems. The heat equation is one of the most well-known PDEs that captures the temperature distribution and diffusion of heat within a body. Due to the wider utility of these equations in various safety-critical applications, such as thermal protection systems, a formal analysis of the heat transfer is of utmost importance. In this paper, we propose to use higher-order-logic (HOL) theorem proving for formally analyzing the heat conduction problem in rectangular coordinates. In particular, we formally model the heat transfer as a one-dimensional heat equation for a rectangular slab using the multivariable calculus theories of the HOL Light theorem prover. This requires the formalization of the heat operator and formal verification of its various properties, such as linearity and scaling. Moreover, we use the separation of variables method for formally verifying the solution of the PDEs, which allows modeling the heat transfer in the slab under various initial and boundary conditions using HOL Light.

Petri nets and their numerous extensions (or subclasses) are one of the popular traditional formalisms for the specification and verification of concurrent systems. Furthermore, due to the expressivity of rewriting logic, Maude and its associated analysis tools have been adopted in many recent works for executing and analyzing Petri nets. In this paper, we first present the existing semantics for the standard Petri nets. Then, we demonstrate the usefulness and the expressivity of the new enhanced semantics that encodes the sets of tokens in a place by their cardinality for such type of Petri nets. Thereafter, we show that such semantics can naturally express different variants of high-level Petri nets such as Petri nets with inhibitor arcs, variable arc weights, and coloured Petri nets. The distinguishing feature of this semantics is that it facilitates the checking of behavioral properties related to boundedness and liveness via the Maude LTL model checker.

This book constitutes the refereed proceedings of the 7th International Workshop on Formal Techniques for Safety-Critical Systems, FTSCS 2019, held in Shenzhen, China, in November 2019. The 6 revised full papers presented were carefully reviewed and selected from 17 submissions. Additionally, the volume presents 1 invited paper, 1 tool paper, and 1 work in progrerss. The papers are focused on the topics of the use of formal methods for analyzing safety-critical systems; methods, techniques and tools to support automated analysis, certication, debugging, etc., of complex safety/QoS-critical systems; analysis methods that address the limitations of formal methods in industry (usability, scalability, etc.); formal analysis support for modeling languages used in industry; code generation from validated models.

Our daily life is increasingly becoming more and more dependent on software as they are being extensively used to control safety and mission-critical systems. This has lead to very stringent verification requirements for ensuring that the software performs as intended. However, the testing based techniques cannot provide a rigorous verification due to limited computational and memory constraints and traditional formal verification techniques, like model checking and theorem proving, are not too straightforward to work with in the industrial setting. In this paper, as a first step to overcome these limitations, we describe a hybrid property based testing and model checking based technique for verifying both models and implementation of access control systems. Our approach addresses the model checking of critical properties of access control systems and aims at improving their reliability by using property based testing to analyze the corresponding software code. For illustration purposes, a simple example of an access control system is used.