Search results for "Signal processing"
showing 10 items of 2451 documents
Non-Parametric Rank Statistics for Spectral Power and Coherence
2019
AbstractDespite advances in multivariate spectral analysis of neural signals, the statistical inference of measures such as spectral power and coherence in practical and real-life scenarios remains a challenge. The non-normal distribution of the neural signals and presence of artefactual components make it difficult to use the parametric methods for robust estimation of measures or to infer the presence of specific spectral components above the chance level. Furthermore, the bias of the coherence measures and their complex statistical distributions are impediments in robust statistical comparisons between 2 different levels of coherence. Non-parametric methods based on the median of auto-/c…
Algorithms for the ROD DSP of the ATLAS Hadronic Tile Calorimeter
2007
In this paper we present the performance of two algorithms currently running in the Tile Calorimeter Read-Out Driver boards for the commissioning of ATLAS. The first algorithm presented is the so called Optimal Filtering. It reconstructs the deposited energy in the Tile Calorimeter and the arrival time of the data. The second algorithm is the MTag which tags low transverse momentum muons that may escape the ATLAS muon spectrometer first level trigger. Comparisons between online (inside the Read-Out Drivers) and offline implementations are done with an agreement around 99% for the reconstruction of the amplitude using the Optimal Filtering algorithm and a coincidende of 93% between the offli…
Flat-top ultra-wideband photonic filters based on mutual coherence function synthesis
2008
A novel all-incoherent optical circuit that allows for band-pass microwave-photonic filter design is presented and verified through numerical simulation. In contrast to conventional spectrum-sliced optical architectures that operate on the basis of a finite number of discrete taps, our proposal is based on arbitrary shaping of the spectrum of the broadband optical source in a conventional frequency encoder. This fact dramatically increases the free spectral range of the filter with respect to the conventional discrete-time optical processing. The filter transfer function is given by the mutual coherence function of the filtered source which allows, through an inverse problem, sculpting the …
Surrogate Data Analysis for Assessing the Significance of the Coherence Function
2004
In cardiovascular variability analysis, the significance of the coupling between two time series is commonly assessed by setting a threshold level in the coherence function. While traditionally used statistical tests consider only the parameters of the adopted estimator, the required zero-coherence level may be affected by some features of the observed series. In this study, three procedures, based on the generation of surrogate series sharing given properties with the original but being structurally uncoupled, were considered: independent identically distributed (IID), Fourier transform (FT), and autoregressive (AR). IID surrogates maintained the distribution of the original series, while …
Extraction and fusion of spectral parameters for face recognition
2011
This is the copy of journal's version originally published in Proc. SPIE 7877: http://spie.org/x10.xml?WT.svl=tn7. Reprinted with permission of SPIE. Many methods have been developed in image processing for face recognition, especially in recent years with the increase of biometric technologies. However, most of these techniques are used on grayscale images acquired in the visible range of the electromagnetic spectrum. The aims of our study are to improve existing tools and to develop new methods for face recognition. The techniques used take advantage of the different spectral ranges, the visible, optical infrared and thermal infrared, by either combining them or analyzing them separately …
Comparison of HapMap and 1000 genomes reference panels in a large-scale genome-wide association study
2017
An increasing number of genome-wide association (GWA) studies are now using the higher resolution 1000 Genomes Project reference panel (1000G) for imputation, with the expectation that 1000G imputation will lead to the discovery of additional associated loci when compared to HapMap imputation. In order to assess the improvement of 1000G over HapMap imputation in identifying associated loci, we compared the results of GWA studies of circulating fibrinogen based on the two reference panels. Using both HapMap and 1000G imputation we performed a meta-analysis of 22 studies comprising the same 91,953 individuals. We identified six additional signals using 1000G imputation, while 29 loci were ass…
Graph Filtering with Quantization over Random Time-varying Graphs
2019
Distributed graph filters can be implemented over wireless sensor networks by means of cooperation and exchanges among nodes. However, in practice, the performance of such graph filters is deeply affected by the quantization errors that are accumulated when the messages are transmitted. The latter is paramount to overcome the limitations in terms of bandwidth and computation capabilities in sensor nodes. In addition to quantization errors, distributed graph filters are also affected by random packet losses due to interferences and background noise, leading to the degradation of the performance in terms of the filtering accuracy. In this work, we consider the problem of designing graph filte…
Internet of Autonomous Vehicles: Architecture, Features, and Socio-Technological Challenges
2019
Mobility is the backbone of urban life and a vital economic factor in the development of the world. Rapid urbanization and the growth of mega-cities is bringing dramatic changes in the capabilities of vehicles. Innovative solutions like autonomy, electrification, and connectivity are on the horizon. How, then, we can provide ubiquitous connectivity to the legacy and autonomous vehicles? This paper seeks to answer this question by combining recent leaps of innovation in network virtualization with remarkable feats of wireless communications. To do so, this paper proposes a novel paradigm called the Internet of autonomous vehicles (IoAV). We begin painting the picture of IoAV by discussing th…
Bandwidth Resource Management for Neural Signal Telemetry
2009
Recent advances in modern neurocomputing have shown the utmost necessity of wireless communication systems that allow real-time (RT) monitoring of neural signals meeting several requirements such as source compression and high fidelity of the received signal. Neural recordings require multielectrode probes with up to hundreds of electrodes and transmission of signals wirelessly over a limited bandwidth (BW). In this paper, a RT resource management algorithm is proposed so that adequate source compression is applied to each channel in order to fit them into the available BW. Performance of the algorithm is analyzed using dynamically changing BW and neural recordings with different neural act…
Cycle-triggered averaging of respiration-related neuronal activity
1985
Abstract A computer system is presented which provides off-line computation of cycle-triggered histograms (CTH) of respiration-related neuronal activity. Binwidths of the histograms are freely selectable by software from 10 ms to 100 ms. For special evaluation purposes. CTHs can be standardized in different ways concerning cycle duration as well as amplitude. Time incidence of maximum frequency, center of gravity and expiration-to-inspiration phase transition within the respiratory cycle are computed. The system employs special hardware interfaces to an 8-bit microcomputer which are briefly described. Data acquisition, data manipulation and output handling of the results are performed by ch…