Model Checking

Abstract—The current proliferation of mobile devices has resulted in a large diversity of hardware specifications, each designed for different services and applications (e.g. cell phones, smart phones, PDAs). At the same time, e-mail message delivery has become a vital part of everyday communications. This article provides a cost-aware study of an RSA-based e-mail protocol executed upon the widely used Apple iPhone1,2 with ARM1176JZF-S, operating in an High Speed Downlink Packet Access (HSDPA) mobile environment. The proposed study employs formal analysis techniques, such as probabilistic model checking, and proceeds to a quantitative analysis of the e-mail protocol, taking into account computational parameters derived by the devices ’ specifications. The value of this study is to form a computer-aided framework which balances the tradeoff between gaining in security, using high-length RSA keys, and conserving CPU resources, due to hardware limitations of mobile devices. To the best...

Abstract. In this article, the development of software for SI2000 digital switch node is described, focusing on software architecture for a MGCP protocol stack. A decoder and an encoder for the MGCP protocol have been developed with the PCCTS tool version 1.33, which supports generation of top-down ÄÄ � parsers in C and C++ programming language. Software planning phase is a very important and time-consuming task, but it is also important to investigate how to implement requested functionality and guarantee proper scalability. To meet the scalability requirements, we had to extend the PCCTS tool with the support for parallel execution of more than one decoder and encoder. Telecommunication management applications also have to support decoding and encoding of MGCP messages. To enable such support for these kinds of applications, we developed an OCX control for the MGCP protocol.

This paper provides a review of Raymond Turner's book ​ Computational Artifacts. Towards a Philosophy of Computer Science​. Focus is made on the definition of program correctness as the twofold problem of evaluating whether ​ both the symbolic program ​ and the physical implementation satisfy a set of specifications. The review stresses how these are not two separate problems. First, it is highlighted how formal proofs of correctness need to rely on the analysis of physical computational processes. Secondly, it is underlined how software testing requires considering the formal relations holding between the specifications and the symbolic program. Such a mutual dependency between formal and empirical program verification methods is finally shown to ​ influence the debate on the epistemological status of computer science.

We introduce a logical verification methodology for checking behavioral properties of service-oriented computing systems. Service properties are described by means of SocL, a branching-time temporal logic that we have specifically designed for expressing in an effective way distinctive aspects of services, such as, acceptance of a request, provision of a response, correlation among service requests and responses, etc. Our approach allows service properties to be expressed in such a way that they can be independent of service domains and specifications. We show an instantiation of our general methodology that uses the formal language COWS to conveniently specify services and the expressly developed software tool CMC to assist the user in the task of verifying SocL formulas over service specifications. We demonstrate the feasibility and effectiveness of our methodology by means of the specification and analysis of a case study in the automotive domain.

We first advocate that the AUML (Agent Unified Modeling Language) notation, even in its new version, is not precise enough to adequately describe protocols. This problem was long identified by Harel and we propose to follow his solution: extend sequence diagrams with a ...

Over the past decade, researchers have demonstrated that the technique of model checking can be extremely effective when applied to security or e-commerce protocols. Model checking is the process of determining whether a formal model of the analyzed system satisfies a correctness property specified as a temporal logic formula. Model checking result is either a claim that the property is true or else a counterexample showing that the property is false. E-Commerce protocols are techniques used to secure E-Commerce transactions. E-Commerce protocols have to own one or more from the security properties like safety, aliveness, authentication, and integrity. Unfortunately, the conventional model checking does not have the definition of these security properties, which are essential for the E-Commerce protocols. In addition, scalability is a desirable property of a protocol, which indicates its ability to handle growing amounts of work in a graceful manner , or to be readily enlarged. In this paper, we extend the conventional NuSMV model checker by adding new predicate layers to enhance its ability for verifying properties of E-Commerce protocols. The new predicates are scalable that are used to check gradient properties of different E-Commerce protocols. The new model combines features for model checking with predicate facilities. The new model can analysis and verify E-Commerce protocols easily and effectively. Therefore, we use to analyze some E-Commerce protocols to verify its security properties.

Social Virtual Reality Learning Environment (VRLE) is a novel edge computing platform for collaboration amongst distributed users. Given that VRLEs are used for critical applications (e.g., special education, public safety training), it is important to ensure security and privacy issues. In this paper, we present a novel framework to obtain quantitative assessments of threats and vulnerabilities for VRLEs. Based on the use cases from an actual social VRLE viz., vSocial, we first model the security and privacy using the attack trees. Subsequently, these attack trees are converted into stochastic timed automata representations that allow for rigorous statistical model checking. Such an analysis helps us adopt pertinent design principles such as hardening, diversity and principle of least privilege to enhance the resilience of social VRLEs.  Through experiments in a vSocial case study, we demonstrate the effectiveness of our attack tree modeling with a reduction of 26% in probability of loss of integrity (security) and 80% in privacy leakage (privacy) in before and after scenarios pertaining to the adoption of the design principles.

This paper presents the investigation and comparison of TLC model checking method (TLA Checker) properties. There are two different approaches to method usage which are considered. The first one consists of a transition system states attendance by breadth-first search (BFS), and the second one by depth-first search (DFS). The Kripke structure has been chosen as a transition system model. A case study has been conducted, where composite web service usage scenario has been considered. Obtained experimental results are aimed at increasing the effectiveness of TLA+ specifications automated verification.

Formal methods are being applied to the development of software of various applications at Philips Healthcare. In particular, the Analytical Software Design (ASD) method is being used as a formal technology for developing defect-free control software of highly sophisticated X-ray machines. In this paper we analyze the effects of applying ASD in the development of various control software units. We compare the quality of these units with other units developed in traditional development methods. The results indicate that applying ASD as a formal technology for developing control software results in better quality code.

We report on a fruitful combination of applying academic experience with formal modelling and verification techniques to an industrial case study. The goal of the case study was to investigate a priori, i.e. before implementation, the effects of adding a lightweight and easy-to-use publish/subscribe (event) notification service to thinkteam r ○ —an asynchronous and dispersed groupware system which was developed by think3. Researchers from the Formal Methods and Tools (FM&T) group of ISTI–CNR—with a longstanding experience in research on the development and application of formal methods, notations, and software tools for the specification, design, and verification of complex computer systems— therefore teamed up with think3—a global provider of integrated product development solutions that provides mechanical design and Product Data Management (PDM) software catering the product management needs of design processes in the manufacturing industry. The technical details of this joint re...

A detailed generic model of the control design process is introduced and discussed. It is used for surveying different formal approaches in the context of PLC programming. The survey focuses on formal methods for verification and validation (V&V). The varying works in this area are categorized using three criteria: the general approach (A) to the task (model based, constraint based or without a model), the formalism (F) (Petri net, automata, etc.,) used to state the formal description, and the method (M) (model-checking, reachability analysis, etc.,) used to analyze the properties. Based on these three criteria (A-F-M) a three letter code for V&V approaches is introduced. Some works from the multitude of V&V research are presented and categorized using this new system

What is the background of this tutorial? During the last decade, the integrative research area of systems biology has constantly been gaining more importance. Experimental and computational approaches are combined to investigate biological systems systematically. To understand biology on its system level, the structural and dynamic properties of regulatory networks in biological systems have to be represented by a model describing the involved species and their interactions. Petri net theory offers the possibility to construct and analyse such models and to represent their structural and dynamic properties by various techniques.

Who should read this tutorial? This tutorial addresses scientists who are looking for an easy and intuitive way to translate a biological system into a Petri net model at an arbitrarily chosen level of abstraction with the option of representing time and space-dependent processes. The tutorial is equally suitable for experimental and theory oriented bio-scientists. The examples given in the tutorial can be used by the interested reader to model her/his biological system.

What can I learn? The tutorial offers an introduction to the Petri net formalism, how to construct a model of a biological system, analyse its structure and dynamic behaviour regarding time-dependent behaviour, which is shown by several intuitive examples. At the end of the tutorial, you will be able to model a biological system on your own using Petri nets. You will also know how to analyse the structure of your model, how to interpret the results and how to perform simulation studies to investigate the time-dependent dynamic behaviour. Also, we also provide a chapter about model checking, which might be helpful to evaluate your model by verifying specified properties that you are interested in. We also show how to use the two Petri net tools Snoopy [19] and Charlie [8]. Based on these instruments you will be able to enhance your knowledge about the modelled biological system and to draw new conclusions from that.

Why should I use Petri nets? The graphical notation and construction of Petri nets allow you to easily and intuitively construct models of biological systems and to characterise the structure, behavioural properties related to the structure and time-dependent dynamic behaviour of a model by several related techniques. Petri nets can describe concurrent and parallel processes, as well as communication and synchronisation in bipartite systems regardless of the abstraction level in a comprehensive and mathematically correct model [12]. Time, as well as space aspects, can be modelled by a Petri net. Several specialised Petri net classes are available to describe dierent scenarios and to consider dierent simulative approaches. Therefore, the kinetics of the qualitative Petri net model can be considered as stochastic, continuous or as a mixture of both (hybrid) [12]. In silico experiments with Petri net models, permit to analyse a biological system systematically by applying structural as well as dynamic analysing techniques to investigate perturbations. From the obtained results new insights can be achieved by the biological system. Thereby, you can increase your understanding, reveal gaps in knowledge, and detect missing and essential components. Based on a valid model it is possible to predict the system behaviour. This might be helpful to investigate pathological states and their molecular basis aimed at identifying potential targets to develop therapeutical intervention strategies. The Petri net formalism offers quite a few advantages over other and more broadly used modelling frameworks. The different Petri net classes are interconvertible with each other without changing the qualitative structure. Due to the graphical visualisation of molecular networks by Petri nets, a bioscientist can intuitively understand the modelled mechanisms. The user does not have to deal with many dierent representations of a molecular network which do not obviously correspond to each other like a biological cartoon, the structure of the biological network, the mathematical equations (stochastic, continuous, etc.) and the implementation of the equations. Besides, the transformation of a molecular network represented by a Petri net into e.g. ODE equations is unique, but not vice versa [24]. Several reliable analysis tools have been developing to investigate qualitative and quantitative properties of Petri nets by structural analysis, simulation of the time-dependent dynamic behaviour and model checking.

What is the scheme of this tutorial? First of all, you will learn all the basics about the Petri net formalism motivated by small biological examples that are easy to understand. Next, you will see how to analyse the structure of a model and how to interpret the obtained results and their biological meaning. Afterwards, you will learn how to perform simulations with your model. We also offer a chapter about model checking, where you can learn how to verify specific properties of your model. Then, we introduce the two Petri net tools Snoopy [19] and Charlie [8]. All sections, where theoretical concepts are explained, are divided into an informal and a formal part. We start with an informal introduction, where we explain the basics and the biological relations. Subsequently and to be complete, we give the formal definitions and a small help on \how to read" the definitions at the end of the section.

What tools do I need? Several tools are available to model biological systems, simulate their time-dependent dynamic behaviour and analyse their structure. Here, we use the Petri net editor Snoopy [19] to model biological systems and simulate/animate their time-dependent dynamic behaviour. Charlie [8] is used to analyse the Petri net structure. Both software tools were developed at the chair of Data Structures and Software Dependability at the Brandenburg University of Technology Cottbus and are freely available for non-commercial use. You can download them at http://www-dssz.informatik. tu-cottbus.de/DSSZ/Software/Software [1].