2,421 research outputs found
Expressing and enforcing user-defined constraints of AADL models
The Architecture Analysis and Design Language AADL allows one to model complete systems, but also to define specific extensions through property sets and library of models. Yet, it does not define an explicit mechanism to enforce some semantics or consistency checks to ensure property sets are correctly used. In this paper, we present REAL (Requirements and Enforcements Analysis Language) as an integrated solution to this issue. REAL is defined as an AADL annex language. It adds the possibility to express constraints as theorems based on set theory to enforce implicit semantics of property sets or AADL models. We illustrate the use of the language on case studies we developed with industrial partners
Characterizing Self-Developing Biological Neural Networks: A First Step Towards their Application To Computing Systems
Carbon nanotubes are often seen as the only alternative technology to silicon
transistors. While they are the most likely short-term one, other longer-term
alternatives should be studied as well. While contemplating biological neurons
as an alternative component may seem preposterous at first sight, significant
recent progress in CMOS-neuron interface suggests this direction may not be
unrealistic; moreover, biological neurons are known to self-assemble into very
large networks capable of complex information processing tasks, something that
has yet to be achieved with other emerging technologies. The first step to
designing computing systems on top of biological neurons is to build an
abstract model of self-assembled biological neural networks, much like computer
architects manipulate abstract models of transistors and circuits. In this
article, we propose a first model of the structure of biological neural
networks. We provide empirical evidence that this model matches the biological
neural networks found in living organisms, and exhibits the small-world graph
structure properties commonly found in many large and self-organized systems,
including biological neural networks. More importantly, we extract the simple
local rules and characteristics governing the growth of such networks, enabling
the development of potentially large but realistic biological neural networks,
as would be needed for complex information processing/computing tasks. Based on
this model, future work will be targeted to understanding the evolution and
learning properties of such networks, and how they can be used to build
computing systems
A MDE-based optimisation process for Real-Time systems
The design and implementation of Real-Time Embedded Systems is now heavily relying on Model-Driven Engineering (MDE) as a central place to define and then analyze or implement a system. MDE toolchains are taking a key role as to gather most of functional and not functional properties in a central framework, and then exploit this information. Such toolchain is based on both 1) a modeling notation, and 2) companion tools to transform or analyse models. In this paper, we present a MDE-based process for system optimisation based on an architectural description. We first define a generic evaluation pipeline, define a library of elementary transformations and then shows how to use it through Domain-Specific Language to evaluate and then transform models. We illustrate this process on an AADL case study modeling a Generic Avionics Platform
Collective Motion of Vibrated Polar Disks
We experimentally study a monolayer of vibrated disks with a built-in polar
asymmetry which enables them to move quasi-balistically on a large persistence
length. Alignment occurs during collisions as a result of self-propulsion and
hard core repulsion. Varying the amplitude of the vibration, we observe the
onset of large-scale collective motion and the existence of giant number
fluctuations with a scaling exponent in agreement with the predicted
theoretical value.Comment: 4 pages, 4 figure
Deep and optically resolved imaging through scattering media by space-reversed propagation
We propose a novel technique of microscopy to overcome the effects of both
scattering and limitation of the accessible depth due to the objective working
distance. By combining Laser Optical Feedback Imaging (LOFI) with Acoustic
Photon Taging (APT) and Synthetic Aperture (SA) refocusing we demonstrate an
ultimate shot noise sensitivity at low power (required to preserve the tissues)
and a high resolution beyond the microscope working distance. More precisely,
with a laser power of 10mW, we obtain images with a micrometric resolution over
~8 transport mean free paths, corresponding to 1.3 times the microscope working
distance. Various applications such as biomedical diagnosis, research and
development of new drugs and therapies can benefit from our imaging setup
Coherent microscopy by laser optical feedback imaging (LOFI) technique
The application of the non conventional imaging technique LOFI (Laser Optical
Feedback Imaging) to coherent microscopy is presented. This simple and
efficient technique using frequency-shifted optical feedback needs the sample
to be scanned in order to obtain an image. The effects on magnitude and phase
signals such as vignetting and field curvature occasioned by the scanning with
galvanometric mirrors are discussed. A simple monitoring method based on phase
images is proposed to find the optimal position of the scanner. Finally, some
experimental results illustrating this technique are presented
Proposition d'une Taxonomie Fonctionnelle des Environnements de Réalité Augmentée
8 pagesL'objectif de cet article est double. Nous proposons premiè- rement une définition des environnements de réalité aug- mentée (RA). Ensuite nous proposons, basée sur notre dé- finition, une nouvelle taxonomie permettant de classer ces environnements. Après une brève revue des classifications existantes, nous définissons la RA par sa finalité qui est de permettre à une personne de réaliser des activités sensori- motrices et cognitives dans un nouvel espace en associant l'environnement réel et un environnement virtuel. Nous pré- sentons ensuite notre taxonomie fonctionnelle des environ- nements de RA. Nous divisons ces environnements en deux groupes distincts. Le premier concerne les différentes fonc- tionnalités permettant de s'informer et de comprendre notre environnement, une perception augmentée de la réalité. Le deuxième correspond aux applications ayant pour finalité de créer un environnement imaginaire. Enfin, plus qu'une dif- férence fonctionnelle, nous démontrons qu'il est possible de considérer que les deux types de RA ont une finalité prag- matique. La différence semble donc tenir à la capacité de ces deux types de RA à s'affranchir ou pas de la localisation spatio-temporelle
- …