554 research outputs found
Live demonstration: Neuro-inspired system for realtime vision tilt correction
Correcting digital images tilt needs huge quantities
of memory, high computational resources, and use to take a
considerable amount of time. This demonstration shows how a
spikes-based silicon retina dynamic vision sensor (DVS) tilt can
corrected in real time using a commercial accelerometer. DVS
output is a stream of spikes codified using the address-event
representation (AER). Event-based processing is focused on
change in real time DVS output addresses. Taking into account
this DVS feature, we present an AER based layer able to correct
in real time the DVS tilt, using a high speed algorithmic
mapping layer and introducing a minimum latency in the
system. A co-design platform (the AER-Robot platform), based
into a Xilinx Spartan 3 FPGA and an 8051 USB microcontroller,
has been used to implement the system
Neuro-inspired system for real-time vision sensor tilt correction
Neuromorphic engineering tries to mimic biological
information processing. Address-Event-Representation (AER)
is an asynchronous protocol for transferring the information of
spiking neuro-inspired systems. Currently AER systems are able
sense visual and auditory stimulus, to process information, to
learn, to control robots, etc. In this paper we present an AER
based layer able to correct in real time the tilt of an AER vision
sensor, using a high speed algorithmic mapping layer. A codesign
platform (the AER-Robot platform), with a Xilinx
Spartan 3 FPGA and an 8051 USB microcontroller, has been
used to implement the system. Testing it with the help of the
USBAERmini2 board and the jAER software.Junta de Andalucía P06-TIC-01417Ministerio de Educación y Ciencia TEC2006-11730-C03-02Ministerio de Ciencia e Innovación TEC2009-10639-C04-0
AER Neuro-Inspired interface to Anthropomorphic Robotic Hand
Address-Event-Representation (AER) is a
communication protocol for transferring asynchronous events
between VLSI chips, originally developed for neuro-inspired
processing systems (for example, image processing). Such
systems may consist of a complicated hierarchical structure
with many chips that transmit data among them in real time,
while performing some processing (for example, convolutions).
The information transmitted is a sequence of spikes coded using
high speed digital buses. These multi-layer and multi-chip AER
systems perform actually not only image processing, but also
audio processing, filtering, learning, locomotion, etc. This paper
present an AER interface for controlling an anthropomorphic
robotic hand with a neuro-inspired system.Unión Europea IST-2001-34124 (CAVIAR)Ministerio de Ciencia y Tecnología TIC-2003-08164-C03-02Ministerio de Ciencia y Tecnología TIC2000-0406-P4- 0
A note on cluster methods for strongly correlated electron systems
We develop, clarify and test various aspects of cluster methods dynamical
mean field methods using a soluble toy model as a benchmark. We find that the
Cellular Dynamical Mean Field Theory (C-DMFT) converges very rapidly and
compare its convergence properties with those of the Dynamical Cluster
Approximation (DCA). We propose and test improved estimators for the lattice
self energy within C-DMFT.Comment: 5 pages, 3 figures; major change
Steady-state expression of self-regulated genes
Motivation: Regulatory gene networks contain generic modules such as feedback loops that are essential for the regulation of many biological functions. The study of the stochastic mechanisms of gene regulation is instrumental for the understanding of how cells maintain their expression at levels commensurate with their biological role, as well as to engineer gene expression switches of appropriate behavior. The lack of precise knowledge on the steady-state distribution of gene expression requires the use of Gillespie algorithms and Monte-Carlo approximations. Methodology: In this study, we provide new exact formulas and efficient numerical algorithms for computing/modeling the steady-state of a class of self-regulated genes, and we use it to model/compute the stochastic expression of a gene of interest in an engineered network introduced in mammalian cells. The behavior of the genetic network is then analyzed experimentally in living cells. Results: Stochastic models often reveal counter-intuitive experimental behaviors, and we find that this genetic architecture displays a unimodal behavior in mammalian cells, which was unexpected given its known bimodal response in unicellular organisms. We provide a molecular rationale for this behavior, and we implement it in the mathematical picture to explain the experimental results obtained from this network. Contact: [email protected], [email protected] Supplementary information: Supplementary data are available at Bioinformatics onlin
Induction of Nod2 in Myelomonocytic and Intestinal Epithelial Cells via Nuclear Factor-kB Activation
Nod2, a member of the Apaf1/Nod protein family, confers responsiveness to bacterial products and activates NF-kB, a ranscription factor that plays a central role in innate immunity. Recently, genetic variation in Nod2
has been associated with susceptibility to Crohn’s disease.
Here, we report that expression of Nod2 is induced upon differentiation of CD34+ hematopoietic progenitor cells into granulocyte or monocyte/macrophages. In peripheral
blood cells, the highest levels of Nod2 were
observed in CD14+ (monocytes), CD15+ (granulocytes), and CD40+/CD86+ (dendritic cells) cell populations. Notably, stimulation of myeloblastic and epithelial cells with bacterial lipopolysaccharide or TNF resulted in
up-regulation of Nod2. A search for consensus sites within the Nod2 promoter revealed a NF-kB binding element that was required for transcriptional activity in
response to TNF . Moreover, ectopic expression of p65 induced transactivation, whereas that of dominant-negative I B blocked the transcriptional activity of the
Nod2 promoter. Upon stimulation with TNF or lipopolysaccharide, both p50 and p65 subunits of NF-kB were bound to the Nod2 promoter. Thus, Nod2 expression is enhanced by proinflammatory cytokines and bacterial
components via NF-kB, a mechanism that may contribute to the amplification of the innate immune response and susceptibility to inflammatory disease
iCanCloud: a flexible and scalable cloud infrastructure simulator
Simulation techniques have become a powerful tool for deciding the best starting conditions on pay-as-you-go scenarios. This is the case of public cloud infrastructures, where a given number and type of virtual machines (in short VMs) are instantiated during a specified time, being this reflected in the final budget. With this in mind, this paper introduces and validates iCanCloud, a novel simulator of cloud infrastructures with remarkable features such as flexibility, scalability, performance and usability. Furthermore, the iCanCloud simulator has been built on the following design principles: (1) it's targeted to conduct large experiments, as opposed to others simulators from literature; (2) it provides a flexible and fully customizable global hypervisor for integrating any cloud brokering policy; (3) it reproduces the instance types provided by a given cloud infrastructure; and finally, (4) it contains a user-friendly GUI for configuring and launching simulations, that goes from a single VM to large cloud computing systems composed of thousands of machines.This research was partially supported
by the following projects: Spanish MEC project
TESIS (TIN2009-14312-C02-01), and Spanish Ministry of
Science and Innovation under the grant TIN2010-16497.Publicad
An AER to CAN Bridge for Spike-Based Robot Control
Address-Event-Representation (AER) is a bio-inspired communication
protocol between chips. A set of AER sensors (retina and cochleas), processors
(convolvers, WTA, mappers, …) and actuators can be found in the literature that
have been specifically designed for mimicking the communication principle in the
brain: spikes. The problem when developing complex robots based on AER (or
spikes) is to command actuators (motors) directly with spikes. Commercial robots
are usually based on commercial standards (CAN) that do not allow powering
actuators directly with spikes. This paper presents a co-design FPGA and
embedded computer system that implements a bridge between these two protocols:
CAN and AER. The bridge has been analyzed under the Spanish project
VULCANO1 with an arm robot and a Shadow anthropomorphic hand.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0
Morocco as a possible domestication center for barley: biochemical and agromorphological evidence.
The distribution of genetic variants of a group of low molecular weight, chloroform-methanol soluble proteins (CM proteins), among Moroccan and non-Moroccan accessions of Hordeum spontaneum and among selections from several Moroccan landraces of H. vulgare and cultivars of the same species with widespread European origin, suggests that domestication of barley might have taken place in Morocco. An agromorphological characterization of the H. spontaneum accessions further supports this hypothesis. The possible Moroccan origin of the French cultivar Hatif de Grignon and of several Spanish 6-rowed barleys is also presented
The role of cover crops in irrigated systems: Soil salinity and salt leaching
Soil salinity and salt leaching are a risk for sustainable agricultural production in many irrigated areas. This study was conducted over 3.5 years to determine how replacing the usual winter fallow with a cover crop (CC) affects soil salt accumulation and salt leaching in irrigated systems. Treatments studied during the period between summer crops were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3 m and used with the numerical model WAVE to calculate drainage. Electrical conductivity (EC) was measured in soil solutions periodically, and in the soil saturated paste extracts before sowing CC and maize. Salt leaching was calculated multiplying drainage by total dissolved salts in the soil solution, and use to obtain a salt balance. Total salt leaching over the four winter fallow periods was 26 Mg ha−1, whereas less than 18 Mg ha−1 in the presence of a CC. Periods of salt gain occurred more often in the CC than in the fallow. By the end of the experiment, net salt losses occurred in all treatments, owing to occasional periods of heavy rainfall. The CC were more prone than the fallow to reduce soil salt accumulation during the early growth stages of the subsequent cash crop
- …