546 research outputs found
Electron Adiabaticity as a Characteristic of Plasma Instabilities in Varying Magnetic Geometries:Observing a Correlation between ITG/TEM Suppression and Enhanced Electron Adiabaticity for Varying Shafranov Shift, Magnetic Shear and Elongation
Augmented Thevenin Model for the Harmonic Analysis of Switching Circuits
This article addresses the use of the Thevenin equivalent model in the case of switching circuits. An augmented Thevenin model is proposed, based on a well-established augmented equivalent approach for the analysis of periodically switched linear networks. It can profitably be used to provide a time-invariant equivalent description of a switching network and to investigate on the harmonics behavior at any of its ports even upon the varying of one of its internal parameters. This makes the article interesting for harmonic analysis purposes as, for instance, in the analysis and troubleshooting of electromagnetic interference or in the monitoring of a system behavior through the assessment and analysis of some of its spectral components. The model has also the advantage to be simple in its implementation. The feasibility and potentiality of the method are verified via simulations and comparisons with the results obtained by applying the augmented equivalent approach to the case of a dc\u2013dc Buck converter
VoIP over WLAN: What about the Presence of Radio Interference?
In this chapter, the performance of VoIP over WLAN is analyzed under the effect of physical
layer interference, in the presence and absence of cross-traffic. The goal is twofold: first to
underline the importance of radio interference in the behavior of a WLAN when supporting
VoIP applications; second to outline solutions to avoid interference and thus optimizing a VoIP
call over aWLAN. To this aim, an experimental approach based on cross-layermeasurements
is adopted, describing and commenting meaningful results
obtained from a number of experiments conducted by the authors on a testbed operating
in a semi-anechoic chamber and emulating two typical real life scenarios
Cross-Layer measurement on an IEEE 802.11g wireless network supporting MPEG-2 video streaming applications in the presence of interference
The performance of wireless local area networks supporting video streaming applications, based on MPEG-2 video codec, in the presence of interference is here dealt with. IEEE 802.11g standard wireless networks, that do not support QoS in according with IEEE 802.11e standard, are, in particular, accounted for and Bluetooth signals, additive white Gaussian noise, and competitive data traffic are considered as sources of interference. The goal is twofold: from one side, experimentally assessing and correlating the values that some performance metrics assume at the same time at different layers of an IEEE 802.11g WLAN delivering video streaming in the presence of in-channel interference; from the other side, deducing helpful and practical hints for designers and technicians, in order to efficiently assess and enhance the performance of an IEEE 802.11g WLAN supporting video streaming in some suitable setup conditions and in the presence of interference. To this purpose, an experimental analysis is planned following a cross-layer measurement approach, and a proper testbed within a semianechoic chamber is used. Valuable results are obtained in terms of signal-to-interference ratio, packet loss ratio, jitter, video quality, and interference data rate; helpful hints for designers and technicians are finally gained
MultiLink Analysis: Brain Network Comparison via Sparse Connectivity Analysis
Abstract The analysis of the brain from a connectivity perspective is revealing novel insights into brain structure and function. Discovery is, however, hindered by the lack of prior knowledge used to make hypotheses. Additionally, exploratory data analysis is made complex by the high dimensionality of data. Indeed, to assess the effect of pathological states on brain networks, neuroscientists are often required to evaluate experimental effects in case-control studies, with hundreds of thousands of connections. In this paper, we propose an approach to identify the multivariate relationships in brain connections that characterize two distinct groups, hence permitting the investigators to immediately discover the subnetworks that contain information about the differences between experimental groups. In particular, we are interested in data discovery related to connectomics, where the connections that characterize differences between two groups of subjects are found. Nevertheless, those connections do not necessarily maximize the accuracy in classification since this does not guarantee reliable interpretation of specific differences between groups. In practice, our method exploits recent machine learning techniques employing sparsity to deal with weighted networks describing the whole-brain macro connectivity. We evaluated our technique on functional and structural connectomes from human and murine brain data. In our experiments, we automatically identified disease-relevant connections in datasets with supervised and unsupervised anatomy-driven parcellation approaches and by using high-dimensional datasets
Implications of routinely measuring ankle-brachial index (ABI) among patients attending at a Lipid Clinic
Efficacy of oxycodone/acetaminophen and codeine/acetaminphen vs conventional therapy in ederly women with persistent moderate to severe osteoarthritis pain
Multi-Sensor UAV Application for Thermal Analysis on a Dry-Stone Terraced Vineyard in Rural Tuscany Landscape
Italian dry-stone wall terracing represents one of the most iconic features of agricultural landscapes across Europe, with sites listed among UNESCO World Heritage Sites and FAO Globally Important Agricultural Heritage Systems (GIAHS). The analysis of microclimate modifications induced by alterations of hillslope and by dry-stone walls is of particular interest for the valuation of benefits and drawbacks of terraces cultivation, a global land management technique. The aim of this paper is to perform a thermal characterization of a dry-stone wall terraced vineyard in the Chianti area (Tuscany, Italy), to detect possible microclimate dynamics induced by dry-stone terracing. The aerial surveys were carried out by using two sensors, in the Visible (VIS) and Thermal InfraRed (TIR) spectral range, mounted on Unmanned Aerial Vehicles (UAVs), with two different flights. Our results reveal that, in the morning, vineyard rows close to dry-stone walls have statistically lower temperatures with respect to the external ones. In the afternoon, due to solar insulation, temperatures raised to the same value for each row. The results of this early study, jointly with the latest developments in UAV and sensor technologies, justify and encourage further analyses on local climatic modifications in terraced landscapes
Unsupervised spike sorting for large-scale, high-density multielectrode arrays
electrophysiology; high-density multielectrode array; neural cultures; retina; spike sortin
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