Automated formal verification of visual modeling languages by model checking

This paper discusses a Unified Modelling Language (UML) based formal verification methodology for early error detection in the model-based software development cycle. Our approach proposes a UML-based formal verification process utilising functional and behavioural modelling artifacts of UML. It reinforces these artifacts with formal model transition and property verification. The main contribution is a UML to Labelled Transition System (LTS) Translator application that automatically converts UML Statecharts to formal models. Property specifications are derived from system requirements and corresponding Computational Tree Logic (CTL)/Linear Temporal Logic (LTL) model checking procedure verifies property entailment in LTS. With its ability to verify CTL and LTL specifications, the methodology becomes generic for verifying all types of embedded system behaviours. The steep learning curve associated with formal methods is avoided through the automatic formal model generation and thus reduces the reluctance of using formal methods in software development projects. A case study of an embedded controller used in military applications validates the methodology. It establishes how the methodology finds its use in verifying the correctness and consistency of UML models before implementation.

To solve the problem that UML (Unified Modeling Language) design model cannot be model-checked for its rough semantics, an extension of UML, called xUML4MC, is defined by extending the activity diagram with accurate syntax and semantics to model the activities of an object. Besides, the technique for automatical transformation of xUML4MC model into MSVL (Modeling, Simulation and Verification Language) model is also presented, which in turn can be verified with model checking tool MSV. The formalism arms the classical visual specification language UML with the power of model checking, and helps to promote the quality of software system.

Unified Modeling Language (UML) has emerged as the software industry’s dominant modeling language. It is the de facto modeling language standard for specifying, visualizing, constructing, and documenting the components of software systems. Despite its prominence and status as the standard modeling language, UML has its critics. Opponents argue that it is complex and difficult to learn. Some question the rationale of having nine diagramming techniques in UML and the raison d’être of those nine techniques in UML. Others point out that UML lacks a comprehensive methodology to guide its users, which makes the language even more convoluted. A few studies on UML can be found in the literature. However, no study exists to provide a quantitative measure of UML complexity or to compare UML with other object-oriented techniques. In this research, we evaluate the complexity of UML using complexity metrics. The objective is to provide a reliable and accurate quantitative measure of UML complexity. A comparison of the complexity metrical values of UML with other object-oriented techniques was also carried out. Our findings suggest that each diagram in UML is not distinctly more complex than techniques in other modeling methods. But as a whole, UML is very complex–2-11 times more complex than other modeling methods.

Unified Modeling Language (UML) has emerged as the software industry’s dominant modeling language. It is the de facto modeling language standard for specifying, visualizing, constructing, and documenting the components of software systems. Despite its prominence and status as the standard modeling language, UML has its critics. Opponents argue that it is complex and difficult to learn. Some question the rationale of having nine diagramming techniques in UML and the raison d’être of those nine techniques in UML. Others point out that UML lacks a comprehensive methodology to guide its users, which makes the language even more convoluted. A few studies on UML can be found in the literature. However, no study exists to provide a quantitative measure of UML complexity or to compare UML with other object-oriented techniques. In this research, we evaluate the complexity of UML using complexity metrics. The objective is to provide a reliable and accurate quantitative measure of UML complexity. A comparison of the complexity metrical values of UML with other object-oriented techniques was also carried out. Our findings suggest that each diagram in UML is not distinctly more complex than techniques in other modeling methods. But as a whole, UML is very complex–2-11 times more complex than other modeling methods.

Summary form only given. Since its adoption in 1997, the unified modeling language (UML) has proved very popular with software engineers and has become the de facto standard as a visual modeling language for software engineers. However, this software focus of UML has discouraged many systems engineers from adopting it in earnest. Those who did adopt UML developed strategies to cope with its shortcomings. A common approach was to model additional systems engineering concepts in other modeling tools. This made it difficult to integrate the different viewpoints and achieve traceability. Fortunately, with the release of UML 2.0 and the ensuing extensions to it in SysML - the soon-to-be adopted systems modeling language - the systems engineering community has a real alternative to systems modeling that provides a more integrated approach to systems and software engineering. Since its inception in 1997, ARTiSAN has endeavored to bridge the gap between systems and software engineering modeling by adding systems engineering extensions to the UML and, as a key member of the SysML initiative, is well poised to support these emerging standards for systems and software modeling. This presentation will provide a brief overview of the major extensions proposed by SysML, and will summarize how ARTiSAN's latest release of its flagship product Studio (version 6.0) takes the lead in supporting these concepts.

In formal design verification, successful model checking is typically preceded by a laborious manual process of constructing design abstractions. We present a methodology for partially—and in some cases, fully—bypassing the abstraction process. For this purpose, we provide to the designer abstraction operators which, if used judiciously in the description of a design, structure the corresponding state space hierarchically. This structure can then be exploited by verification tools, and makes possible the automatic and exhaustive exploration of state spaces that would otherwise be out of scope for existing model checkers.Specifically, we present the following contributions: - A temporal abstraction operator that aggregates transitions and hides intermediate steps. Mathematically, our abstraction operator is a function that maps a flat transition system into a two-level hierarchy where each atomic upper-level transition expands into an entire lower-level transition system. For example, an arithmetic operation may expand into a sequence of bit operations. - A BDD-based algorithm for the symbolic exploration of multi-level hierarchies of transition systems. The algorithm traverses a level-n transition by expanding the corresponding level-(n − 1) transition system on-the-fly. The level-n successors of a state are determined by computing a level-(n − 1) reach set, which is then immediately released from memory. In this fashion, we can exhaustively explore hierarchically structured state spaces whose flat counterparts cause memory overflows. - We experimentally demonstrate the efficiency of our method with three examples—a multiplier, a cache coherence protocol, and a multiprocessor system. In the first two examples, we obtain significant improvements in run times and peak BDD sizes over traditional state-space search. The third example cannot be model checked at all using conventional methods (without manual abstractions), but can be analyzed fully automatically using transition hierarchies. KeywordsModel CheckTransition RelationParallel CompositionReactive ModuleReachability AnalysisThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Model checking is a technique for finding bugs in systems by systematically exploring their state spaces. We wish to extract sound models from concurrent programs automatically and check the behaviors of these models systematically. The zing project is an effort to build a flexible infrastructure to represent and model check abstractions of large concurrent software.To support automatic extraction of models from programs written in common programming languages, zing’s modeling language supports three facilities present in modern programming languages: (1) procedure calls with a call-stack, (2) objects with dynamic allocation, and (3) processes with dynamic creation, using both shared memory and message passing for communication. We believe that these three facilities capture the essence of model checking modern concurrent software.Building a scalable model-checker for such an expressive modeling language is a huge challenge. zing’s modular architecture provides a clear separation between the expressive semantics of the modeling language, and a simple view of zing programs as labeled transition systems. This separation has allowed us to decouple the design of efficient model checking algorithms from the complexity of supporting rich constructs in the modeling language. zing’s model checking algorithms have been designed to exploit existing structural abstractions in concurrent programs such as processes and procedure calls. We present two such novel techniques in the paper: (1) compositional checking of zing models for message-passing programs using a conformance theory inspired by work in the process algebra community, and (2) a new summarization algorithm, which enables zing to reuse work at procedure boundaries by extending interprocedural data-flow analysis algorithms from the compiler community to analyze concurrent programs.KeywordsModel CheckModeling LanguageProcedure CallLabel Transition SystemConcurrent ProgramThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Unified Modeling Language is being used for modeling of business processes, real-time systems, embedded systems and hybrid systems. In software engineering, there are different techniques for verification of such systems. Model checking is one of the techniques for the automatic verification of software models. Earlier, these model were verified by sequential model checking tools. For very large complex systems, parallel verification can save verification time. DiVinE is a model checking tool for both CPUs and GPUs clusters to perform parallel linear time logic (LTL) verification of systems. In this paper, we propose a parallel verification methodology for UML models using DiVinE tool. We explain this methodology by the case study example of fuel filling machine.

Security protocols ensure secure communication between and within systems such as internet services, factories, and smartphones. As evidenced by numerous successful attacks against popular protocols such as TLS, designing protocols securely is a tedious and error-prone task. Model checkers greatly aid protocol verification, yet any single model checker is oftentimes insufficient to check a protocol's security in full. Instead, engineers are forced to maintain multiple overlapping and hopefully non-contradicting and non-diverging specifications, one per model-checking tool---an error-prone task.To address this problem, this paper presents VICE, a scenario-based approach to security-protocol verification. It provides a visual modeling language based for specifying security protocols independent of the model checker. It then automatically transforms the relevant fragments of these models into equivalent inputs to multiple model checkers. In result, VICE completely relieves the security engineer from choosing and specifying queries via a fully automatic generation of all necessary queries.Through a case study involving real-world specifications of eight security protocols, we show that VICE is applicable in practice.

The main purpose of this paper is to present knowledge-based Enterprise model (EM) sufficiency as data repository for Unified Modelling Language (UML) models generation. UML models are one of the most usable modelling languages in system lifecycle design stage, despite the problem domain of the system. UML models can be generated from Enterprise Model by using particular transformation algorithms presented in previous researches. Generation process from Enterprise model is represented by certain Hospital Information Management process example. Generated UML dynamic Use Case, Activity, Sequence and State models of different perspectives of Hospital Information Management process prove sufficiency of stored information in Enterprise model.

In formal verification, reliable results are of utmost importance. In model checking of digital systems, mainly incorrect implementations of the model checking algorithms due to logical errors are the source of wrong results. In probabilistic model checking, however, numerical instabilities are an additional source for inconsistent results. We motivate our investigations with an example, for which several state-of-the-art probabilistic model checking tools give completely wrong results due to inexact computations. We then analyze, at which points inaccuracies are introduced during the model checking process. We discuss first ideas how, in spite of these inaccuracies, reliable results can be obtained or at least the user be warned about potential correctness problems: (1) usage of exact (rational) arithmetic, (2) usage of interval arithmetic to obtain safe approximations of the actual probabilities, (3) provision of certificates which testify that the result is correct, and (4) integration of a "degree of belief" for each sub-formula into existing model checking tools.

The intimate relationship between model checking and abstract interpretation has been shown in a large number of relevant papers in literature. Maybe the use of abstract interpretation to reduce the well-known state space explosion problem in model checking was the first and most successful combination of these two techniques. However, this is not the only possible way both methods can collaborate to improve the software reliability. Along these last 20 years, our contributions in this area have been focussed on the practical application of abstract interpretation in the context of model checking tools. From our point of view, model checking tools such as spin can be hardly improved in terms of efficiency. Thus, we have concentrated on applying abstraction to completely reuse the underlying model checkers. We have applied our ideas to different modelling and programming languages, tools and real applications. In this paper, we summarize some of these contributions.

Software product line (SPL) is a software engineering paradigm for software development. A software product within a product line often has specific functionalities that are not common to all other products within the product line. Those specific functionalities are termed “variant features” in a product line. SPL paradigm involves the modeling of variant features. However, little work in SPL investigates and addresses the modeling of variant features specific to user interface (UI). Unified Modeling Language (UML) is the de facto modeling language for object-oriented software systems. It is known that UML needs better support in modeling UIs. Thus, much research developed UML extensions to improve UML support in modeling UIs. Yet little of this work is related to developing such extensions for modeling UIs for SPLs in which variant features specific to UI modeling must be addressed. This research develops a UML extension -Web User Interface Modeling Language (WUIML) to address these problems. WUIML defines elements for modeling variant features specific to user interfaces for Web-based SPLs. The model elements in WUIML extend from the metaclass and BasicActivity of the UML2.0 metamodel. WUIML integrates the modeling of variant features specific to user interfaces to UML. For example, in a Web-based patient registration software product line, member products targeting British users may use British date format in the user interface, while member products targeting United States users may use United States date format in the user interface. Thus, this is a variant feature for this product line. WUIML defines a model element, XOR, to represent such exclusive or conditions in a product line user interface model. WUIML would reduce SPL engineers’ efforts needed in UI development. To validate the WUIML research outcome, a case study was conducted. The results of this empirical study indicate that modeling UIs for Web-based SPLs using WUIML is more effective and efficient than using standard UML.

The emergence of the Unified Modeling Language (UML) has provided software developers with an effective and efficient shared language. However, UML is often too restrictive in initial, informal, and creative modelling, and it is in some cases not restrictive enough, e.g., for code generation. Based on user studies, we propose that tool and meta-level support for several levels of restriction in diagrams and models is needed. We furthermore present a tool, Knight, which supports several levels of restriction as well as ways of transferring models from one level of restriction to another. This approach potentially increases the usability of the UML, and thus ultimately leads to greater quality and adoption of UML models.KeywordsUnify Modeling LanguageUnify Modeling Language ModelUnify Modeling Language DiagramUnify Modeling Language MetamodelUnify Modeling Language ToolThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

In this chapter, we provide the essential theory and practical details of employing the principles of Object Orientation (OO) in system architecture modeling. We do not attempt to provide an exhaustive OO tutorial, since there exists a very large literature on this subject (see the references to this chapter). Our goal, instead, is to give the reader the level of understanding needed to master the MBSAP methodology and apply it to practical system architecting challenges. First, we present the rationale for OO and define the essential concepts and terminology, stressing the benefits it delivers in dealing with complex entities. Although we use the Systems Modeling Language (SysML) as the basis for this book, we begin by discussing and illustrating the primary diagrams of the Unified Modeling Language (UML), which is the root language standard for OO. This is then followed by a description of the changes to UML introduced by the SysML, which is defined as a Profile of UML. The reality is that a large part of the SysML is taken directly from the UML language specification. We believe understanding of this material is enhanced by first considering the parent UML and then explicitly showing how UML modifies and extends the language. We include generic UML and SysML diagrams that illustrate important principles and syntax and that can serve as format samples in developing real architecture models. Appendices A and B are concise references to UML and SysML, respectively, intended to give readers a quick and easy way to look up the details. Chapter objective: the reader will be able to create and read UML and SysML diagrams and to describe the role of each.