Search results for " tuning"
showing 10 items of 39 documents
Recent improvements on micro-thermocouple based SThM
2017
The scanning thermal microscope (SThM) has become a versatile tool for local surface temperature mapping or measuring thermal properties of solid materials. In this article, we present recent improvements in a SThM system, based on a micro-wire thermocouple probe associated with a quartz tuning fork for contact strength detection. Some results obtained on an electrothermal micro-hotplate device, operated in active and passive modes, allow demonstrating its performance as a coupled force detection and thermal measurement system.
Topographic Independent Component Analysis reveals random scrambling of orientation in visual space
2017
Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space. There is an active debate on the origin of these locally continuous maps. While most of the existing descriptions take purely geometric/mechanistic approaches whi…
Extraordinary tuning of a nanocavity by a near-field probe
2011
Abstract We report here an experimental observation of an extraordinary near-field interaction between a local probe and a small-volume solid-state nanocavity. We directly compare the normally observed near-field interaction regime driven by the perturbation theory and then report the extraordinary interaction regime. Subsequently, we show that the cavity can take up to 2 min to recover from this interaction after removing the probe and that leads to an extraordinary blue-shift of the cavity resonance wavelength (∼15 nm) which depends on the probe motion above the cavity and not the position. The reasons for this effect are not fully understood yet but we try to give some explanations.
Both attention and prediction are necessary for adaptive neuronal tuning in sensory processing
2014
International audience; The brain as a proactive system processes sensory information under the top-down influence of attention and prediction. However, the relation between attention and prediction remains undetermined given the conflation of these two mechanisms in the literature. To evaluate whether attention and prediction are dependent of each other, and if so, how these two top-down mechanisms may interact in sensory processing, we orthogonally manipulated attention and prediction in a target detection task. Participants were instructed to pay attention to one of two interleaved stimulus streams of predictable/unpredictable tone frequency. We found that attention and prediction intera…
HEp-2 intensity classification based on deep fine-tuning
2020
The classification of HEp-2 images, conducted through Indirect ImmunoFluorescence (IIF) gold standard method, in the positive / negative classes, is the first step in the diagnosis of autoimmune diseases. Since the test is often difficult to interpret, the research world has been looking for technological features for this problem. In recent years the methods of deep learning have overcome the other machine learning techniques in their effectiveness and robustness, and now they prevail in artificial intelligence studies. In this context, CNNs have played a significant role especially in the biomedical field. In this work we analysed the capabilities of CNN for fluorescence classification of…
Examination of robust D-stability of TCP-DCR protocol
2012
This paper presents non-linear mathematical model of a computer network with a part of wireless network. The article contains an analysis of the stability of the network based on TCP-DCR, which is a modification of the traditional TCP. Block diagram of the network model was converted to a form in order to investigate the D-stability using the method of the space of uncertain parameters. Robust D-stability is calculated for constant delays values.
Adaptive Low Priority Packet Marking for Better TCP Performance
2003
This paper proposes a packet marking scheme for TCP traffic. Unlike previous literature work, in our scheme the majority of TCP packets are transmitted as high priority. The role of a low priority packet appears that of a probe, whose goal is to early discover network congestion conditions. Low priority packets are marked according to an adaptive marking algorithm. Numerical results show that our scheme provides improved throughput/delay performance.
TCP Performance in Mobile Ad hoc Networks
2013
International audience; In this paper, we present a survey of TCP (Transmission Control Protocol) protocol for better performance in the MANET (Mobile Ad Hoc Network). After a short presentation of the main features of TCP, we give the most important problems from which TCP suffer in MANET. We present after that some approaches proposed in the literature in order to improve its performance. Our paper contains also a performance evaluation of TCP NewReno and TCP Vegas transport protocols under AODV and DSR routing protocols. The simulations are conducted under varying conditions of number of TCP connections, number of nodes and mobility.
Adaptive tuning system and parameter estimation of a digitally controlled boost converter with STM32
2019
. This paper proposes a diagnostic system of a power electronic converter, based on a cheap STM32 Nucleo board, aiming to extract some relevant measurements which gives back important values of the converter's parameters behavior. Moreover the designed system is also exploited for implementing the converter's auto tuning in order to optimize its dynamic performance.
Early Brain Sensitivity to Word Frequency and Lexicality During Reading Aloud and Implicit Reading
2019
The present study investigated the influence of lexical word properties on the early stages of visual word processing (<250 ms) and how the dynamics of lexical access interact with task-driven top-down processes. We compared the brain's electrical response (event-related potentials, ERPs) of 39 proficient adult readers for the effects of word frequency and word lexicality during an explicit reading task versus a visual immediate-repetition detection task where no linguistic intention is required. In general, we observed that left-lateralized processes linked to perceptual expertise for reading are task independent. Moreover, there was no hint of a word frequency effect in early ERPs, while …