Formal method Research Papers - Academia.edu (original) (raw)

The future of Open Distributed Processing systems (ODP) will see an increasing of components number, these components are sharing resources. In general, these resources are offering some kind of services. Due to the huge number of... more

The future of Open Distributed Processing systems (ODP) will see an increasing of components number, these components are sharing resources. In general, these resources are offering some kind of services. Due to the huge number of components, it is very difficult to offer the optimum Quality of service (QoS). This encourages us to develop a model for QoS negotiation process to optimize the QoS in an ODP system. In such system, there is a High risk of software or hardware failure. To ensure good performance of a system based on our model, we develop it using a formal method. In our case, we will use Event-B to get in the end of our development a system correct by construction.

In this work, we present a method for approximating constrained maximum entropy (ME) reconstructions of SPECT data with modifications to a block-iterative maximum a posteriori (MAP) algorithm. Maximum likelihood (ML)-based reconstruction... more

In this work, we present a method for approximating constrained maximum entropy (ME) reconstructions of SPECT data with modifications to a block-iterative maximum a posteriori (MAP) algorithm. Maximum likelihood (ML)-based reconstruction algorithms require some form of noise smoothing. Constrained ME provides a more formal method of noise smoothing without requiring the user to select parameters. In the context of SPECT, constrained ME seeks the minimum-information image estimate among those whose projections are a given distance from the noisy measured data, with that distance determined by the magnitude of the Poisson noise. Images that meet the distance criterion are referred to as feasible images. We find that modeling of all principal degrading factors (attenuation, detector response, and scatter) in the reconstruction is critical because feasibility is not meaningful unless the projection model is as accurate as possible. Because the constrained ME solution is the same as a MAP solution for a particular value of the MAP weighting parameter, beta, the constrained ME solution can be found with a MAP algorithm if the correct value of beta is found. We show that the RBI-MAP algorithm, if used with a dynamic scheme for estimating beta, can approximate constrained ME solutions in 20 or fewer iterations. We compare results for various methods of achieving feasible images on a simulation of Tl-201 cardiac SPECT data. Results show that the RBI-MAP ME approximation provides images and quantitative estimates close to those from a slower algorithm that gives the true ME solution. Also, we find that the ME results have higher spatial resolution and greater high-frequency noise content than a feasibility-based stopping rule, feasibility-based low-pass filtering, and a quadratic Gibbs prior with beta selected according to the feasibility criterion. We conclude that fast ME approximation is possible using either RBI-MAP with the dynamic procedure or a feasibility-based stopping rule, and that such reconstructions may be particularly useful in applications where resolution is critical.

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... more

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.

The complex requirements of software systems justify the use of the best existing techniques to guar- antee the quality of speciflcations and to preserve this quality during the programming,phase of a software life-cycle. On the one hand,... more

The complex requirements of software systems justify the use of the best existing techniques to guar- antee the quality of speciflcations and to preserve this quality during the programming,phase of a software life-cycle. On the one hand, visual speciflcation lan- guages (such as UML) have been widely used for spec- ifying, visualizing, understanding and documenting software systems, but they

In this paper we introduce a model as a foundation for het-erogeneous services, therefore unifying web services tech-nologies in SOA (Service Oriented Architecture), specif-ically, SOAP/WS * and RESTful models. This model ab-stracts away... more

In this paper we introduce a model as a foundation for het-erogeneous services, therefore unifying web services tech-nologies in SOA (Service Oriented Architecture), specif-ically, SOAP/WS * and RESTful models. This model ab-stracts away from service implementations, in order to verify and to enforce some important security properties.

Abstract. In the last three years or so we at Enterprise Platforms Group at Intel Corporation have been applying formal methods to various problems that arose during the process of defining platform architectures for Intel’s processor... more

Abstract. In the last three years or so we at Enterprise Platforms Group at Intel Corporation have been applying formal methods to various problems that arose during the process of defining platform architectures for Intel’s processor families. In this paper we give an overview of some of the problems we have worked on, the results we have obtained, and the lessons we have learned. The last topic is addressed mainly from the perspective of platform architects. 1. Problems and Results Modern computer systems are highly complex distributed systems with many interacting components. Architecturally they are often organized like a computer network into multiple layers: physical layer, link layer, protocol layer, etc. Most of the problems to which we applied formal methods are the formal verification (FV) of intricate protocols in the protocol and link layers. In addition, we also found several novel uses of binary decision diagrams (BDDs) [3] that are worth mentioning. 1.1. Directory-bas...

Formal methods and testing are two important approaches that assist in the development of high-quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they... more

Formal methods and testing are two important approaches that assist in the development of high-quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing.

Incomplete, inaccurate, ambiguous, and volatile requirements have plagued the software industry since its inception. The convergence of model-based develop- ment and formal methods ofiers developers of safety- critical systems a powerful... more

Incomplete, inaccurate, ambiguous, and volatile requirements have plagued the software industry since its inception. The convergence of model-based develop- ment and formal methods ofiers developers of safety- critical systems a powerful new approach for the early validation of requirements. This paper describes a case study conducted to determine if formal methods could be used to validate system requirements early in the lifecycle at reasonable cost. Several hundred functional and safety requirements for the mode logic of a typical Flight Guidance System were captured as natural lan- guage \shall" statements. A formal model of the mode logic was written in the RSML¡e language and trans- lated into the NuSMV model checker and the PVS the- orem prover using translators developed as part of the project. Each \shall" statement was manually translated into a NuSMV or PVS property and proven using these tools. Numerous errors were found in both the origi- nal requirements and ...

This report describes a formal approach to verification and validation of safety requirements for embedded software, by application to a simple control-logic case study. The logic is formally specified in Z. System safety properties are... more

This report describes a formal approach to verification and validation of safety requirements for embedded software, by application to a simple control-logic case study. The logic is formally specified in Z. System safety properties are formalised by defining an abstract model of the system’s physical behaviour in Z, including its hazardous states and dominant sensor failures. The Possum specification-animation tool is then used to check that the logic meets its safety requirements. Finally, the logic is implemented in SPARK Ada and SPARK Examiner is used to formally verify the implementation meets its specification. Design safety validation and source code verification are completely automated, removing the need for

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... more

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.

The answer to software reliability concerns may lie in formal methods.

Formal methods have yet to achieve wide industrial acceptance for several reasons. They are not well integrated into established industrial software processes, their application requires significant abstraction and mathematical skills,... more

Formal methods have yet to achieve wide industrial acceptance for several reasons. They are not well integrated into established industrial software processes, their application requires significant abstraction and mathematical skills, and existing tools do not satisfactorily support the entire formal software development process. We have proposed a language called SOFL (Structured-Object-based-formal Language) and a SOFL methodology for system development that attempts to address these problems using an ...

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... more

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...

We summarize some current trends in embedded systems design and point out some of their characteristics, such as the chasm between analytical and computational models, and the gap between safety-critical and best-effort engineering... more

We summarize some current trends in embedded systems design and point out some of their characteristics, such as the chasm between analytical and computational models, and the gap between safety-critical and best-effort engineering practices. We call for a coherent scientific foundation for embedded systems design, and we discuss a few key demands on such a foundation: the need for encompassing several manifestations of heterogeneity, and the need for constructivity in design. We believe that the development of a satisfactory Embedded Systems Design Science provides a timely challenge and opportunity for reinvigorating computer science.

Object orientation and formal methods are widely regarded as two fields with significant potential for new software engineering techniques. This paper discusses the relations between these two approaches. We present various specification... more

Object orientation and formal methods are widely regarded as two fields with significant potential for new software engineering techniques. This paper discusses the relations between these two approaches. We present various specification techniques which incorporate object-oriented paradigms, discuss their place in software development process, and analyse possible benefits from their applications.

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... more

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