The VerCors tool for verification of concurrent programs

The VerCors tool implements thread-modular static verification of concurrent programs, annotated with functional properties and heap access permissions. The tool supports both generic multithreaded and vector-based programming models. In particular, it can verify multithreaded programs written in Java, specified with JML extended with separation logic. It can also verify parallelizable programs written in a toy language that supports the characteristic features of OpenCL. The tool verifies programs by first encoding the specified program into a much simpler programming language and then applying the Chalice verifier to the simplified program. In this paper we discuss both the implementation of the tool and the features of its specification language

Contracting the Facebook API

In recent years, there has been an explosive growth in the popularity of online social networks such as Facebook. In a new twist, third party developers are now able to create their own web applications which plug into Facebook and work with Facebook's "social" data, enabling the entire Facebook user base of more than 400 million active users to use such applications. These client applications can contain subtle errors that can be hard to debug if they misuse the Facebook API. In this paper we present an experience report on applying Microsoft's new code contract system for the .NET framework to the Facebook API.We wrote contracts for several classes in the Facebook API wrapper which allows Microsoft .NET developers to implement Facebook applications. We evaluated the usefulness of these contracts during implementation of a new Facebook application. Our experience indicates that having code contracts provides a better and quicker software development experience.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

Special section on advances in reachability analysis and decision procedures: contributions to abstraction-based system verification

Reachability analysis asks whether a system can evolve from legitimate initial states to unsafe states. It is thus a fundamental tool in the validation of computational systems - be they software, hardware, or a combination thereof. We recall a standard approach for reachability analysis, which captures the system in a transition system, forms another transition system as an over-approximation, and performs an incremental fixed-point computation on that over-approximation to determine whether unsafe states can be reached. We show this method to be sound for proving the absence of errors, and discuss its limitations for proving the presence of errors, as well as some means of addressing this limitation. We then sketch how program annotations for data integrity constraints and interface specifications - as in Bertrand Meyers paradigm of Design by Contract - can facilitate the validation of modular programs, e.g., by obtaining more precise verification conditions for software verification supported by automated theorem proving. Then we recap how the decision problem of satisfiability for formulae of logics with theories - e.g., bit-vector arithmetic - can be used to construct an over-approximating transition system for a program. Programs with data types comprised of bit-vectors of finite width require bespoke decision procedures for satisfiability. Finite-width data types challenge the reduction of that decision problem to one that off-the-shelf tools can solve effectively, e.g., SAT solvers for propositional logic. In that context, we recall the Tseitin encoding which converts formulae from that logic into conjunctive normal form - the standard format for most SAT solvers - with only linear blow-up in the size of the formula, but linear increase in the number of variables. Finally, we discuss the contributions that the three papers in this special section make in the areas that we sketched above. © Springer-Verlag 2009

The known unknowns of hydraulic engineering

Hydraulic engineers and researchers deal with scientific challenges involving turbulent flow motion and its interactions with the surroundings. Turbulent flows are characterised by unpredictable behaviour, and little systematic research has yet been conducted in natural systems. This paper discusses the implications of recent developments in affordable instrumentation previously characterised by intrinsic weaknesses that adversely affect the quality of the signal outputs. A challenging application is the unsteady turbulence field in tidal bores. The interactions between open channel flows and movable boundaries and atmosphere illustrate another aspect of our limited knowledge. Rapid siltation of reservoirs and air entrainment in turbulent free-surface flows are discussed. In both applications, hydraulic engineers require some broad-based expertise. In turn the education of future hydraulic engineers is of vital importance

HUDSON HEALTH CORRIDOR: REDEFINING THE WORKFORCE HOUSING COMMUNITY

Neighborhoods slated for redevelopment and revitalization within urban centers are often overtaken by luxury development due to the incentives and benefits related to return on investment in these relatively ignored areas. Developers tend to create housing that will attract higher incomes in order to gain higher returns, resulting in the creation of an exclusive area marketed to particular groups within a certain income bracket. These areas then grow in popularity, continuing to attract upper class residents, and increasing the income level of the area. The result of this type of development displaces those who previously occupied these areas because they are no longer able to afford the various options and become priced out of their homes. Those with an income below the target market in these neighborhoods are never able to occupy them at all. This thesis aims to counter the problem. Instead of beginning revitalization with living options exclusive to higher incomes, these communities can instead be anchored by affordable housing options. This involves developing affordable housing marketed to the working class at the initial phase of redevelopment. By combining workforce housing with a health platform, flexible and adaptive spaces can be produced to fit a variety of family types, balance community, and maintain economic sustainability for the future. Through this approach, it is possible for different residents to find housing situations that fit their family with adaptable units for a variety of income levels. A community focus in design becomes an economic driver to produce revenue as well as an attractor of neighborhood residents to help break down barriers and perceptions commonly associated with workforce housing. Architecture has the potential to change the way in which society views and treats workforce housing and its residents. By challenging the current development process, a new approach can be created where residents feel valued and community engagement becomes the forefront of workforce housing design

SCJ-Circus : a refinement-oriented formal notation for Safety-Critical Java

Safety-Critical Java (SCJ) is a version of Java whose goal is to support the development of real-time, embedded, safety-critical software. In particular, SCJ supports certification of such software by introducing abstractions that enforce a simpler architecture, and simpler concurrency and memory models. In this paper, we present SCJ-Circus, a refinement-oriented formal notation that supports the specification and verification of low-level programming models that include the new abstractions introduced by SCJ. SCJ-Circus is part of the family of state-rich process algebra Circus, as such, SCJ-Circus includes the Circus constructs for modelling sequential and concurrent behaviour, real-time and object orientation. We present here the syntax and semantics of SCJ-Circus, which is defined by mapping SCJ-Circus constructs to those of standard Circus. This is based on an existing approach for modelling SCJ programs. We also extend an existing Circus-based refinement strategy that targets SCJ programs to account for the generation of SCJ-Circus models close to implementations in SCJ

La ville désenchantée ? Sécularisation et laïcisation des espaces urbains français (XIXe_XXe siècles)

L'espace urbain français a connu une sécularisation et une laïcisation progressive, mais non linéaire, depuis la Révolution. En effet, malgré une déchristianisation certaine, l'Eglise catholique a développé des formes multiples d'intervention sociale qui expliquent peut_être ses fortes réticences à accepter un islam dorénavant solidement établi comme seconde religion en France et très présent dans la société française

Auslautendes -e und -i in der Mundart von Villagrande Strisaili (Sardinien)

In occasione di ricerche dialettologiche svolte sul posto, si è potuto constatare che la presunta conservazione della -e finale latina nel dialetto di Villagrande non corrisponde ai fatti.A differenza delle parlate campidanesi, il mutamento di -e in -i finale nel dialetto villagrandese costituisce uno sviluppo fonetico limitato alle voci proparossitone. Probabilmente questo sviluppo è dovuto alla loro caratteristica accentazione sdrucciola. Inoltre, si osserva una presenza diffusa di -i finale al posto di -e in alcune voci parossitone la cui causa potrebbe essere spiegata in parte per l’azione dell’analogia, in parte per una meridionalizzazione occasionale di singole parole del dialetto locale

Introduction

Reconnaissance de l'altérité, de la diversité et de la liberté d'expression égale pour tous, la laïcité est, par définition, une valeur universaliste et humaniste, positive et inclusive (affirmation des libertés individuelles et publiques) avant d'être négative (séparation des Eglises et de l'Etat) ou exclusive (libre-pensée). Elle a toujours été contestée : sur le principe, dès l'origine; dans la pratique, dès qu'on est passé au stade de son institutionnalisation. Elle l'est à nouveau depuis une décennie, et de manière parfois virulente, par des discours religieux, idéologiques et politiques qui lui imputent la responsabilité partielle ou totale de la crise des valeurs, du matérialisme, et des échecs sociaux et politiques des sociétés contemporaines nées de la modernité occidentale