Search results for "Signal"
showing 10 items of 6924 documents
UAV-Aided Multi-Antenna Covert Communication Against Multiple Wardens
2021
In this paper, we propose a UAV-aided covert communication scheme assisted by a multi-antenna jammer to maximize the transmission rate between a ground transmitter and a UAV receiver against several randomly distributed wardens. The transmitter adopts the maximum ratio transmission, while the jammer zero-forces its transmitted signal at the UAV to disturb the monitoring at wardens without interfering the legitimate transmission. First, we analyze the detection performance and derive the optimal threshold for each warden to minimize its detection outage probability (DOP). Then, with the worst situation in which all wardens set their respective optimal thresholds to achieve the minimum global…
Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models
2015
In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with …
Augmented Reality in minimally invasive otologic surgery and transmodiolar cochlear implantation
2021
Optimal exposure is necessary for minimally invasive otologic surgery. Augmented reality allows to enrich the real environment by adding data without replacing it by a virtual environment and to view this information on a single screen by combining the vision of the operating field and the imaging. This technique is very little described in otology in the literature. This project aims to develop augmented reality solutions for otological surgeries and transmodiolar implantation. To prepare this augmented reality project, we studied the visualization of the middle ear by a virtual endoscope based on preoperative high resolution CT-scans. Then, we worked on the application of augmented realit…
Design of a transverse flux machine for power generation from seawaves
2014
In this paper, we present a transverse flux linear generator. We investigate the possibility to use this generator to extract energy from seawaves. We propose an optimization procedure that allows us to obtain an optimized design of the generator. The optimized design of the converter shows a power generation capability index much higher than other renewable systems.
Improved heuristics for the regenerator location problem
2014
Telecommunication systems use optical signals to transmit information. The strength of a signal in an optical network deteriorates and loses power as it goes farther from the source, mainly due to attenuation. Therefore, to enable the signal to arrive its intended destination with good quality, it is necessary to regenerate the signal periodically using regenerators. These components are relatively expensive and therefore it is desirable to deploy as few of them as possible in the network. In the regenerator location problem (RLP), we are given an undirected graph, positive edge lengths, and a parameter specifying the maximum length that a signal can travel before its quality deteriorates a…
Right-arm rotation distance between binary trees
2003
We consider a transformation on binary trees, named right-arm rotation, which is a special instance of the well-known rotation transformation. Only rotations at nodes of the right arm of the trees are allowed. Using ordinal tools, we give an efficient algorithm for computing the right-arm rotation distance between two binary trees, i.e., the minimum number of rightarm rotations necessary to transform one tree into the other.
Modeling of neuron-astrocyte interaction : application to signal and image processing
2022
The introduction of the tripartite synapse and the discovery of calcium wave propagation motivated our research to explore the potential of astrocytes as active components in brain circuits. For decades, astrocytes have been considered passive cells whose primary function is metabolic and structural support to neurons; however, recent physiological measurements suggest that astrocytes modulate neural communication, strengthen synaptic efficacy, enhance synchronization, and promote homeostasis. Inspired by these biological functions, this research aimed to implement astrocytes in artificial spiking networks for deep learning applications. First, we modeled the biological interaction between …
Astrocytes in culture express the full-length Trk-B receptor and respond to brain derived neurotrophic factor by changing intracellular calcium level…
2000
Abstract Although cultured astroglial cells were reported to express exclusively the truncated non-catalytic Trk B receptor for brain-derived neurotrophic factor (BDNF), we detect here, using a sensitive ribonuclease protection assay, mRNAs for both truncated (TrkB–T) and the full length catalytic (TrkB–fl) form of BDNF receptor in developing cortical astrocytes and neurons in culture. Cortical neurons and immature astroglia, such as radial glia and proliferating astrocytes, express both the protein and mRNAs for TrkB-fl and TrkB-T, whereas the differentiation of astrocytes leads to a decrease in the trkB-fl mRNA, being the truncated TrkB the predominant receptor in differentiating and conf…
Damping excessive inflammation and tissue damage in Mycobacterium tuberculosis infection by Toll IL-1 receptor 8/single Ig IL-1-related receptor, a n…
2007
Abstract Toll IL-1R 8/single Ig IL-1-related receptor (TIR8/SIGIRR) is a member of the IL-1R family, expressed by epithelial tissues and immature dendritic cells, and is regarded as a negative regulator of TLR/IL-1R signaling. Tir8-deficient mice were rapidly killed by intranasal administration of low doses of Mycobacterium tuberculosis, despite controlling efficiently the number of viable bacilli in different organs. Tir8−/−-infected mice showed an increased number of neutrophils and macrophages in the lungs; however, mycobacteria-specific CD4 and CD8 T cells were similar in Tir8−/− and Tir8+/+ mice. Exaggerated mortality of Tir8−/− mice was due to massive liver necrosis and was accompanie…
Mycobacterium tuberculosis secretory proteins downregulate T cell activation by interfering with proximal and downstream T cell signalling events
2015
Background Mycobacterium tuberculosis (M. tuberculosis) modulates host immune response, mainly T cell responses for its own survival leading to disease or latent infection. The molecules and mechanisms utilized to accomplish immune subversion by M. tuberculosis are not fully understood. Understanding the molecular mechanism of T cell response to M. tuberculosis is important for development of efficacious vaccine against TB. Methods Here, we investigated effect of M. tuberculosis antigens Ag85A and ESAT-6 on T cell signalling events in CD3/CD28 induced Peripheral blood mononuclear cells (PBMCs) of PPD+ve healthy individuals and pulmonary TB patients. We studied CD3 induced intracellular calc…