Search results for "coding"
showing 10 items of 920 documents
Les récepteurs olfactifs et le codage des odeurs
2008
The first step of the olfactory detection involves the activation by odorants of olfactory receptors, which are membrane proteins embedded in the membrane of olfactory neurons. Odour coding results from the combinatory activation of a set of receptors and rests on their clonal expression. Neuronal olfactory connexion leads to the formation, in the cortex, of a specific sensory map, which gives rise to the odor perception. This combinatorial system allows, with approximately 340 different receptors, to discriminate myriads of odorants that are natural or not (new cooking flavours, synthetic chemicals…). The extreme olfactory genome diversity in human beings may explain different food behavio…
MUSIC-LS Modal Channel Estimation for an OFDM-OQAM System
2008
Orthogonal frequency division multiplexing based on offset quadrature amplitude modulation (OFDM-OQAM) signaling over frequency selective multipath channels shows inter-symbol interference (ISI) and Inter-Channel Interference (ICI) that degrade its performance. Channel equalization and channel estimation are needed to combat these intrinsic interferences. In this paper a novel modal channel estimator based on the MUltiple signal classification (MUSIC) and least squares (LS) algorithms for a wideband passband OFDM-OQAM signaling over static multipath channels is presented. The effects of the frequency selective channel on the received signal are described considering a wideband OFDM-OQAM sys…
Re-Clustering tool using an Open-Reference method that improves OTU definition
2019
International audience; 1.Environmental microbial communities are now widely studied using metabarcoding approaches, thanks to the democratization of high‐throughput DNA sequencing technologies. The massive number of reads produced with these technologies requires bioinformatic solutions to be treated. A key step in the analysis is to cluster reads into Operational Taxonomic Units (or OTUs) and thus reduce the amount of data for downstream analyses. Due to the important impact of the clustering method on the quantity and quality of OTUs, finding an equilibrium between the reliability and time‐consuming nature of the chosen strategy is a real challenge. The present article proposes a new pos…
Serum coding and non-coding RNAs as biomarkers of NAFLD and fibrosis severity
2019
Background: In patients with NAFLD liver biopsy is the gold standard to detect NASH and stage liver fibrosis. We aimed to identify differentially expressed mRNAs and non-coding RNAs in serum samples of biopsy-diagnosed mild and severe NAFLD patients with respect to controls and to each other. Methods: We first performed a whole transcriptome analysis through microarray (n=12: 4 CTRL; 4 mild NAFLD: NAS≤4 F0; 4 severe NAFLD NAS≥5 F3), followed by validation of selected transcripts through qPCRs in 88 subjects: 63 NAFLD, 25 CTRL. A similar analysis was also performed on HepG2 exposed to Oleate:Palmitate or only Palmitate (cellular model of NAFL/NASH) at intracellular/extracellular levels. Tran…
Temperature Cues Bias the Memory of Trustworthiness of Faces
2016
Humans rely on temperature cues to navigate and make sense of their social world. In two experiments we find that part of this process can be detected in the perception and memory of faces. We conducted two studies to find this effect through a method called “reverse correlation”, where we average a face over a large amount of trials. For participants who experienced physical warmth (vs. cold) at the initial confrontation with a face we found that the average of the trials displayed a psychologically warmer face (judged by independent raters). Excluding the possibility of a “carry-over” effect, in Study 2 we replicated the Study 1 effect, but only if physical warmth (vs. cold) preceded the …
Optical CDMA enhanced by nonlinear optics
2010
Intended for the next generation of optical access networks, OCDMA is of great interest to meet the demand of increasing the number of users per access fiber, especially as spectral phase coding increases its performance in the optical domain. This, however, requires handling broad spectra and short pulses, which are best dealt with using opto-electronic or all-optical devices instead of slower electronics. Among others, we demonstrate spectral-phase-coded OCDMA using a fiber-based saturable absorber as thresholding in the receiver.
Spatial information transmission using axial temporal coherence coding
2007
We present an approach that can be used for transmission of information through space-limited systems or for superresolution. The spatial information is coded with different axial temporal coherence by interfering every spatial region in the input with the same region, but with a certain known delay in the longitudinal axis. Every spatial region has different delay. After mixing all of the spatial information, it is transmitted through the space-limited system. At the detection the information is passed through a similar interference setup containing certain axial delay. By temporally scanning along the longitudinal axis, each time a different spatial region that was coded with the correspo…
Distributed Resource Allocation for Energy Efficiency in OFDMA Multicell Networks with Wireless Power Transfer
2019
In this paper, an energy-efficient resource allocation problem is investigated for the wireless power transfer (WPT)-enabled OFDMA multicell networks. In the considered system, multiple base stations (BSs) with a large number of antennas are responsible to provide WPT in the downlink, and the users can recycle and utilize the received energy for uplink data transmission. The role of BS is to execute WPT; thus, there are no data transmissions in the downlink. A time-division protocol is considered to divide the time of downlink WPT and uplink wireless information transfer into separate time slots. With the objective to improve the energy efficiency, we propose the time, subcarrier, and power…
Designing Precoding and Receive Matrices for Interference Alignment in MIMO Interference Channels
2017
Interference is a key bottleneck in wireless communication systems. Interference alignment is a management technique that align interference from other transmitters in the least possibly dimension subspace at each receiver and provides the remaining dimensions for free interference signal. An uncoordinated interference is an example of interference which cannot be aligned coordinately with interference from coordinated part; consequently, the performance of interference alignment approaches are degraded. In this paper, we propose a rank minimization method to enhance the performance of interference alignment in the presence of uncoordinated interference sources. Firstly, to obtain higher mu…
Efficient Simulation of Orthogonal Multicarrier Transmission over Multipath Fading Channels
2011
Filterbank orthogonal multicarrier transmission schemes, such as OFDM/OQAM, are currently under intense study for their spectral efficiency and suitability for the physical layer of Cognitive Radio. Nonetheless, the mathematical description of the signal is cumbersome, and closed form expressions for performance figures are not available, so performance analysis on fading channels has to be performed by means of simulations. We propose an algorithm for simulating the received signal over multipath frequency selective fading channels, based on Taylor series expansion of the channel transfer function. The proposed method is compared to the state-of-the-art FFT-based method in terms of computa…