An Improved Algorithm for Generating Database Transactions from Relational Algebra Specifications

Alloy is a lightweight modeling formalism based on relational algebra. In prior work with Fisler, Giannakopoulos, Krishnamurthi, and Yoo, we have presented a tool, Alchemy, that compiles Alloy specifications into implementations that execute against persistent databases. The foundation of Alchemy is an algorithm for rewriting relational algebra formulas into code for database transactions. In this paper we report on recent progress in improving the robustness and efficiency of this transformation

Towards a method for rigorous development of generic requirements patterns

We present work in progress on a method for the engineering, validation and verification of generic requirements using domain engineering and formal methods. The need to develop a generic requirement set for subsequent system instantiation is complicated by the addition of the high levels of verification demanded by safety-critical domains such as avionics. Our chosen application domain is the failure detection and management function for engine control systems: here generic requirements drive a software product line of target systems. A pilot formal specification and design exercise is undertaken on a small (twosensor) system element. This exercise has a number of aims: to support the domain analysis, to gain a view of appropriate design abstractions, for a B novice to gain experience in the B method and tools, and to evaluate the usability and utility of that method.We also present a prototype method for the production and verification of a generic requirement set in our UML-based formal notation, UML-B, and tooling developed in support. The formal verification both of the structural generic requirement set, and of a particular application, is achieved via translation to the formal specification language, B, using our U2B and ProB tools

Independent Component Separation from incomplete spherical data using wavelets. Application to CMB data analysis

Spectral matching ICA (SMICA) is a source separation method based on covariance matching in Fourier space that was designed to address in a flexible way some of the general problems raised by Cosmic Microwave Background data analysis. However, a common issue in astronomical data analysis is that the observations are unevenly sampled or incomplete maps with missing patches or intentionally masked parts. In addition, many astrophysical emissions are not well modeled as stationary processes over the sky. These effects impair data processing techniques in the spherical harmonics representation. This paper describes a new wavelet transform for spherical maps and proposes an extension of SMICA in this space-scale representation

Demonstrating that Medical Devices Satisfy User Related Safety Requirements

One way of contributing to a demonstration that a medical device is acceptably safe is to show that the device satisfies a set of requirements known to mitigate hazards. This paper describes experience using formal techniques to model an IV infusion device and to prove that the modelled device captures a set of requirements. The requirements chosen for the study are based on a draft proposal developed by the US Food and Drug Administration (FDA). A major contributor to device related errors are (user) interaction errors. For this reason the chosen models and requirements focus on user interface related issues.FEDER - Federación Española de Enfermedades Raras(000062)This work has been funded by the EPSRC research grant EP/G059063/1: CHI+MED (Computer–Human Interaction for Medical Devices). J. C. Campos was funded by project NORTE-07-0124-FEDER-00006

Modular Verification for a Class of PLTL Properties

The verification of dynamic properties of a reactive systems by model-checking leads to a potential combinatorial explosion of the state space that has to be checked. In order to deal with this problem, we define a strategy based on local verifications rather than on a global verification. The idea is to split the system into subsystems called modules, and to verify the properties on each module in separation. We prove for a class of PLTL properties that if a property is satisfied on each module, then it is globally satisfied. We call such properties modular properties. We propose a modular decomposition based on the B refinement process. We present in this paper an usual class of dynamic properties in the shape of G (p -> Q), where `p' is a proposition and `Q' is a simple temporal formula, such as `X q', `F q', or `q U r' (with `q' and `r' being propositions). We prove that these dynamic properties are modular. For these specific patterns, we have exhibited some syntactic conditions of modularity on their corresponding Buchi automata. These conditions define a larger class which contains other patterns such as `G (p -> X (q U r))'. Finally, we show through the example of an industrial Robot that this method is valid in a practical way

Formalising the Continuous/Discrete Modeling Step

Formally capturing the transition from a continuous model to a discrete model is investigated using model based refinement techniques. A very simple model for stopping (eg. of a train) is developed in both the continuous and discrete domains. The difference between the two is quantified using generic results from ODE theory, and these estimates can be compared with the exact solutions. Such results do not fit well into a conventional model based refinement framework; however they can be accommodated into a model based retrenchment. The retrenchment is described, and the way it can interface to refinement development on both the continuous and discrete sides is outlined. The approach is compared to what can be achieved using hybrid systems techniques.Comment: In Proceedings Refine 2011, arXiv:1106.348

Wavelets, ridgelets and curvelets on the sphere

We present in this paper new multiscale transforms on the sphere, namely the isotropic undecimated wavelet transform, the pyramidal wavelet transform, the ridgelet transform and the curvelet transform. All of these transforms can be inverted i.e. we can exactly reconstruct the original data from its coefficients in either representation. Several applications are described. We show how these transforms can be used in denoising and especially in a Combined Filtering Method, which uses both the wavelet and the curvelet transforms, thus benefiting from the advantages of both transforms. An application to component separation from multichannel data mapped to the sphere is also described in which we take advantage of moving to a wavelet representation.Comment: Accepted for publication in A&A. Manuscript with all figures can be downloaded at http://jstarck.free.fr/aa_sphere05.pd

Association of Under-Approximation Techniques for Generating Tests from Models

International audienceIn this paper we present a Model-Based Testing approach with which we generate tests from an abstraction of a source behavioural model. We show a new algorithm that computes the abstraction as an under-approximation of the source model. Our first contribution is to combine two previous approaches proposed by Ball and Pasareanu et al. to compute May, Must+ and Must- abstract transition relations. Prooftechniques are used to compute these transition relations. The tests obtained by covering the abstract transitions have to be instantiated from the source model. So, following Pasareanu et al., our algorithm additionally computes a concrete transition relation: the tests obtained as sequences of concrete transitions need not be instantiated from the source model. Another contribution is to propose a choice of relevant paramaters and heuristics to pilot the tests computation. We experiment our approach and compare it with a previous approach of ours to compute tests from an abstraction that over-approximates the source model

Towards a single-chip, implantable RFID system: is a single-cell radio possible?

We present an overview of progress towards single-chip RFID solutions. To date heterogeneous integration has been appropriate for non-biological systems. However, for in-vivo sensors and even drug delivery systems, a small form factor is required. We discuss fundamental limits on the size of the form factor, the effect of the antenna, and propose a unified single-chip RFID solution appropriate for a broad range of biomedical in-vivo device applications, both current and future. Fundamental issues regarding the possibility of single cell RF radios to interface with biological function are discussed