Multi-layered Spiking Neural Network with Target Timestamp Threshold Adaptation and STDP

Spiking neural networks (SNNs) are good candidates to produce ultra-energy-efficient hardware. However, the performance of these models is currently behind traditional methods. Introducing multi-layered SNNs is a promising way to reduce this gap. We propose in this paper a new threshold adaptation system which uses a timestamp objective at which neurons should fire. We show that our method leads to state-of-the-art classification rates on the MNIST dataset (98.60%) and the Faces/Motorbikes dataset (99.46%) with an unsupervised SNN followed by a linear SVM. We also investigate the sparsity level of the network by testing different inhibition policies and STDP rules

Array-OL Revisited, Multidimensional Intensive Signal Processing Specification

This paper presents the Array-OL specification language. It is a high-level visual language dedicated to multidimensional intensive signal processing applications. It allows to specify both the task parallelism and the data parallelism of these applications on focusing on their complex multidimensional data access patterns. This presentation includes several extensions and tools developed around Array-OL during the last few years and discusses the mapping of an Array-OL specification onto a distributed heterogeneous hardware architecture

Unsupervised Visual Feature Learning with Spike-timing-dependent Plasticity: How Far are we from Traditional Feature Learning Approaches?

Spiking neural networks (SNNs) equipped with latency coding and spike-timing dependent plasticity rules offer an alternative to solve the data and energy bottlenecks of standard computer vision approaches: they can learn visual features without supervision and can be implemented by ultra-low power hardware architectures. However, their performance in image classification has never been evaluated on recent image datasets. In this paper, we compare SNNs to auto-encoders on three visual recognition datasets, and extend the use of SNNs to color images. The analysis of the results helps us identify some bottlenecks of SNNs: the limits of on-center/off-center coding, especially for color images, and the ineffectiveness of current inhibition mechanisms. These issues should be addressed to build effective SNNs for image recognition

Another Multidimensional Synchronous Dataflow: Simulating Array-OL in Ptolemy II

Computation intensive multidimensional applications appear in many application domains such as video processing or detection systems. We present here the Array-OL specification model to handle such multidimensional applications. This model is compared to the Multidimensional Synchronous Dataflow proposition by Lee et al. We also detail in this a new domain in the Ptolemy simulation environment dedicated to Array-OL specification simulation

PMS+: Un outil pour les processus de production de logiciels

Toutes approche IDM nécessite l'enchaînement de plusieurs transformations. Cet enchaînement peut être vu comme un processus de production de logiciels. Dans le plus simple des cas, cet enchaînement est linéaire : les transformations s'exécutent les unes après les autres. Cependant, il arrive souvent que l'on ait besoin de contrôler l'enchaînement lors de l'exécution : par exemple, on peut vouloir choisir la transformation suivante en fonction du résultat des transformations précédentes. Dans cet article, nous décrivons l'outil PMS+ permettant de spécifier l'enchaînement de transformations en tant que processus de production de logiciels

Network Analysis of the French Environmental Code

We perform a detailed analysis of the network constituted by the citations in a legal code, we search for hidden structures and properties. The graph associated to the Environmental code has a small-world structure and it is partitioned in several hidden communities of articles that only partially coincide with the organization of the code as given by its table of content. Several articles are also connected with a low number of articles but are intermediate between large communities. The structure of the Environmental Code is contrasting with the reference network of all the French Legal Codes that presents a rich-club of ten codes very central to the whole French legal system, but no small-world property. This comparison shows that the structural properties of the reference network associated to a legal system strongly depends on the scale and granularity of the analysis, as is the case for many complex systemsComment: AI Approaches to the Complexity of Legal Systems (AICOL 2009), Rotterdam : Netherlands (2009

Graphs for Ontology, Law and Policy

Le livre est en accès libre. The book is in open acces

The Network of French Legal Codes

We propose an analysis of the codified Law of France as a structured system. Fifty two legal codes are selected on the basis of explicit legal criteria and considered as vertices with their mutual quotations forming the edges in a network which properties are analyzed relying on graph theory. We find that a group of 10 codes are simultaneously the most citing and the most cited by other codes, and are also strongly connected together so forming a "rich club" sub-graph. Three other code communities are also found that somewhat partition the legal field is distinct thematic sub-domains. The legal interpretation of this partition is opening new untraditional lines of research. We also conjecture that many legal systems are forming such new kind of networks that share some properties in common with small worlds but are far denser. We propose to call "concentrated world"

Repetitive Model Refactoring for Design Space Exploration of Intensive Signal Processing Applications

The efficient design of computation intensive multidimensional signal processing application requires to deal with three kinds of constraints: those implied by the data dependencies, the non functional requirements (real-time, power consumption) and the availability of resources of the execution platform. We propose here a strategy to use a refactoring tool dedicated to this kind of applications to help explore the design space. This strategy is illustrated on an industrial radar application modeled using the Modeling and Analysis of Real-time and Embedded systems (MARTE) UML profile. It allows to find good trade-offs in the usage of storage and computation resources and in the parallelism (both task and data parallelism) exploitation