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1

SIGNAL PROCESSING FOR ADVANCED CORRELATION ULTRASONIC VELOCITY PROFILER  

Microsoft Academic Search

The objective of the present study is to develop a high-time resolution ultrasonic velocity profiler system by improving a signal processing algorithm and to apply it to turbulent flow measurement. The time resolution of an existing ultrasonic velocity profiler systems is limited to the order of 10 ms at the best due to its signal processing technique, the fact of

Yousuke Sato; Michitsugu Mori; Yasushi Takeda; Koichi Hishida; Masanobu Maeda

2

Spectral correlation in ultrasonic pulse echo signal processing.  

PubMed

The effects of using spectral correlation in a maximum-likelihood estimator (MLE) for backscattered energy corresponding to coherent reflectors embedded in media of microstructure scatterers is considered. The spectral autocorrelation (SAC) function is analyzed for various scatterer configurations based on the regularity of the interspacing distance between scatterers. It is shown that increased regularity gives rise to significant spectral correlation, whereas uniform distribution of scatters throughout a resolution cell results in no significant correlation between spectral components. This implies that when a true uniform distribution for the effective scatterers exists, the power spectral density (PSD) is sufficient to characterize their echoes. However, as the microstructure scatterer distribution becomes more regular, SAC terms become more significant. MLE results for 15 A-scans from stainless steel specimens with three different grain sizes indicate an average 6-dB signal-to-noise ratio (SNR) improvement in the coherent scatterer (flat-bottom hole) echo intensities for estimators using the SAC characterization as opposed to the PSD characterization. PMID:18263188

Donohue, K D; Bressler, J M; Varghese, T; Bilgutay, N M

1993-01-01

3

Correlation techniques for the improvement of signal-to-noise ratio in measurements with stochastic processes  

NASA Astrophysics Data System (ADS)

An AC modulation technique is described to convert stochastic signal variations into an amplitude variation and its retrieval through Fourier analysis. It is shown that this AC detection of signals of stochastic processes when processed through auto- and cross-correlation techniques improve the signal-to-noise ratio; the correlation techniques serve a similar purpose of frequency and phase filtering as that of phase-sensitive detection. A few model calculations applied to nuclear spectroscopy measurements such as Angular Correlations, Mossbauer spectroscopy and Pulse Height Analysis reveal considerable improvement in the sensitivity of signal detection. Experimental implementation of the technique is presented in terms of amplitude variations of harmonics representing the derivatives of normal spectra. Improved detection sensitivity to spectral variations is shown to be significant. These correlation techniques are general and can be made applicable to all the fields of particle counting where measurements are amenable to "dual modulation". The proposed AC modulation technique may be applied in diverse fields like pulse height analysis in nuclear spectroscopy, XRD, XRF, RBS, ESCA, positronium resonance, photon counting etc., for enhancing the S/ N ratio.

Reddy, V. Raghavendra; Gupta, Ajay; Reddy, T. Goverdhan; Reddy, P. Yadagiri; Reddy, K. Rama

2003-04-01

4

Cross-Correlation: An fMRI Signal-Processing Strategy  

PubMed Central

The discovery of functional MRI (fMRI), with the first papers appearing in 1992, gave rise to new categories of data that drove the development of new signal-processing strategies. Workers in the field were confronted with image time courses, which could be reshuffled to form pixel time courses. The waveform in an active pixel time-course was determined not only by the task sequence but also by the hemodynamic response function. Reference waveforms could be cross-correlated with pixel time courses to form an array of cross-correlation coefficients. From this array of numbers, colorized images could be created and overlaid on anatomical images. An early paper from the authors’ laboratory is extensively reviewed here (Bandettini et al. 1993. Magn. Reson. Med. 30:161–173). That work was carried out using the vocabulary of vector algebra. Cross-correlation methodology was central to the discovery of functional connectivity MRI (fcMRI) by Biswal et al. (1995. Magn. Reson. Med. 34:537–541). In this method, a whole volume time course of images is collected while the brain is nominally at rest and connectivity is studied by cross-correlation of pixel time courses. PMID:22051223

Hyde, James S.; Jesmanowicz, Andrzej

2011-01-01

5

Signal Processing: Introduction Digital Signal Processing  

E-print Network

Signal Processing: Introduction Digital Signal Processing Introduction Areas of Applications signals and processing #12;Signal Processing: Introduction DSP in various disciplines Communication, Finance ( Economic models, Stock market) and many more #12;Signal Processing: Introduction DSP

Rimon, Elon

6

Signal processing  

SciTech Connect

Space-variant coordinate transformations may be profitably applied to many signal-processing problems; for example, image convolutions are often computed by multiplying the Fourier transforms of the images rather than by direct methods (i.e., shift, multiply, and add). Some signal-processing algorithms are presently under study that operate on projection-based representations of the function. The best-known projection representation is the Radon transform (Radon, 1917) (Easton, 1986), which is the mathematical basis for several medical imaging techniques, e.g., medical computed tomography (CT or CAT) and nuclear magnetic resonance imaging (MRI). The Radon transform reduces the two-dimensional (2-D) data set to a series of 1-D line-integral projections at each azimuth. 8 refs.

Easton, R.L. Jr.

1990-01-01

7

Signal processing  

NASA Astrophysics Data System (ADS)

Space-variant coordinate transformations may be profitably applied to many signal processing problems; for example, image convolutions are often computed by multiplying the Fourier transforms of the images rather than by direct methods (i.e., shift, multiply, and add). Some signal processing algorithms are presently under study that operate on projection-based representations of the function. The best known projection representation is the Radon transform (Radon, 1917) (Easton, 1986), which is the mathematical basis for several medical imaging techniques, e.g., medical computed tomography (CT or CAT) and nuclear magnetic resonance imaging (MRI). The Radon transform reduces the 2-D data set to a series of 1-D line integral projections at each azimuth.

Easton, Roger L., Jr.

1990-01-01

8

Signal processing  

NASA Astrophysics Data System (ADS)

The application of signal processing technology to conventional weapons systems can lower operator workloads and enhance kill probabilities, while automating wide-area surveillance, target search and classification, target tracking, and aimpoint selection. Immediate opportunities exist for automatic target cueing in underwater and over-the-horizon targeting, as well as for airborne multiple-target fire control. By embedding the transit/receive electronics into conformal aircraft sensor arrays, a 'smart' skin can be created. Electronically scanned phased arrays can be used to yield accurate azimuthal and elevation positions while nullifying EW threats. Attention is given to major development thrusts in algorithm design.

Norman, David M.

9

Signal from noise: Insights into volcanic system processes from ambient noise correlations  

NASA Astrophysics Data System (ADS)

This first section of dissertation concerns the imaging of the crust and upper most mantle structure of the mid-Miocene volcanic provinces of the Northwestern United States using ambient noise tomography. Chapter 1 introduces the complex tectonic history of the northwestern United States and describes the development of volcanism from the ignimbrite sweep that occurred with the extension of the Basin and Range province, initiation and evolution of the mid-Miocene volcanism of the Steens/Columbia River flood basalts, and mirror-image volcanic tracks of the High Lava Plains, Oregon and Yellowstone-Snake River Plains. Chapter 2 describes in detail the concepts and methods for determining the 3D shear velocity structure in the crust and uppermost mantle from ambient noise correlations. Chapter 3 contains the text and supplementary materials of Hanson-Hedgecock et al. [2012] published in the Geophysical Research Letters that describes the application of the ambient noise methods to the imaging of the Western United States. The second section of this work discusses the results of measuring velocity changes associated with three episodes of increased eruptive activity at Tungurahua in 2010 using ambient noise correlations. The third section of this work discusses the results of using the H/V ratio to measure the level of equipartition of the ambient noise wavefield at Tungurahua in 2010.

Hanson-Hedgecock, Sara

10

Signal Processing Information Base  

NSDL National Science Digital Library

The Signal Processing Information Base(SPIB) is a project sponsored by the Signal Processing Society and the National Science Foundation. SPIB is a repository of data, papers, software, newsgroups, bibliographies, and addresses of interest to the signal processing community, as well as links to other relevant repositories.

11

Digital Signal Processing  

NSDL National Science Digital Library

Digital signal processing is a technique that uses digital methods to process signals. Processing a signal means manipulating it to improve it, change it, or alter it as required for some application. Some examples of processes are filtering, modulation and demodulation, mixing, spectrum analysis, compression and decompression, and many others. In the past, most of these processes have been accomplished with analog techniques and circuits. Today, that has changed. While analog processing has not disappeared, it is slowly being replaced by digital processing in most applications. DSP is now used in almost all electronic equipment and knowledge of its operation is critical to an overall knowledge and understanding of electronics. In digital processing, the analog signal to be processed is first converted to digital then processing is done by a computer. The computer output is then converted back to analog. This module describes this process and outlines the most common applications.

12

Digital signal processing  

NASA Astrophysics Data System (ADS)

Signal and image processing research projects are described. Topics include: (1) modeling underwater acoustic propagation; (2) image restoration; (3) signal reconstruction; (4) speech enhancement; (5) pitch detection; (6) spectral analysis; (7) speech synthesis; (8) speech enhancement; (9) autoregressive spectral estimation; (10) knowledge based array processing; (11) speech analysis; (12) estimating the degree of coronary stenosis with image processing; (13) automatic target detection; and (14) video conferencing.

Oppenheim, A. V.; Baggeroer, A. B.; Lim, J. S.; Musicus, B. R.; Mook, D. R.; Duckworth, G. L.; Bordley, T. E.; Curtis, S. R.; Deadrick, D. S.; Dove, W. P.

1984-01-01

13

Radiation signal processing system  

SciTech Connect

An improved signal processing system for radiation imaging apparatus comprises: a radiation transducer producing transducer signals proportional to apparent spatial coordinates of detected radiation events; means for storing true spatial coordinates corresponding to a plurality of predetermined apparent spatial coordinates relative to selected detected radiation events said means for storing responsive to said transducer signal and producing an output signal representative of said true spatial coordinates; and means for interpolating the true spatial coordinates of the detected radiation events located intermediate the stored true spatial coordinates, said means for interpolating communicating with said means for storing.

Bennett, M.; Knoll, G.; Strange, D.

1980-07-08

14

Array signal processing  

SciTech Connect

This is the first book to be devoted completely to array signal processing, a subject that has become increasingly important in recent years. The book consists of six chapters. Chapter 1, which is introductory, reviews some basic concepts in wave propagation. The remaining five chapters deal with the theory and applications of array signal processing in (a) exploration seismology, (b) passive sonar, (c) radar, (d) radio astronomy, and (e) tomographic imaging. The various chapters of the book are self-contained. The book is written by a team of five active researchers, who are specialists in the individual fields covered by the pertinent chapters.

Haykin, S.; Justice, J.H.; Owsley, N.L.; Yen, J.L.; Kak, A.C.

1985-01-01

15

Parallel signal processing  

NASA Astrophysics Data System (ADS)

The potential application of parallel computing techniques to digital signal processing for radar is discussed and two types of regular array processor are discussed. The first type of processor is the systolic or wavefront processor. The application of this type of processor to adaptive beamforming is discussed and the joint STL-RSRE adaptive antenna processor test-bed is reviewed. The second type of regular array processor is the SIMD parallel computer. One such processor, the Mil-DAP, is described, and its application to a varied range of radar signal processing tasks is discussed.

McWhirter, John G.

1989-12-01

16

OPTIMAL CORRELATION ESTIMATORS FOR QUANTIZED SIGNALS  

SciTech Connect

Using a maximum-likelihood criterion, we derive optimal correlation strategies for signals with and without digitization. We assume that the signals are drawn from zero-mean Gaussian distributions, as is expected in radio-astronomical applications, and we present correlation estimators both with and without a priori knowledge of the signal variances. We demonstrate that traditional estimators of correlation, which rely on averaging products, exhibit large and paradoxical noise when the correlation is strong. However, we also show that these estimators are fully optimal in the limit of vanishing correlation. We calculate the bias and noise in each of these estimators and discuss their suitability for implementation in modern digital correlators.

Johnson, M. D.; Chou, H. H.; Gwinn, C. R., E-mail: michaeltdh@physics.ucsb.edu, E-mail: cgwinn@physics.ucsb.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

2013-03-10

17

Soft digital signal processing  

Microsoft Academic Search

In this paper, we propose a framework for low-energy digital signal processing (DSP), where the supply voltage is scaled beyond the critical voltage imposed by the requirement to match the critical path delay to the throughput. This deliberate introduction of input-dependent errors leads to degradation in the algorithmic performance, which is compensated for via algorithmic noise-tolerance (ANT) schemes. The resulting

Rajamohana Hegde; Naresh R. Shanbhag

2001-01-01

18

Optimum combining of residual carrier array signals in correlated noises  

NASA Technical Reports Server (NTRS)

An array feed combining system for the recovery of signal-to-noise ratio (SNR) loss due to antenna reflector deformation has been implemented and is currently being evaluated on the Jet Propulsion Laboratory 34-m DSS-13 antenna. The current signal-combining system operates under the assumption that the white Gaussian noise processes in the received signals from different array elements are mutually uncorrelated. However, experimental data at DSS 13 indicate that these noise processes are indeed mutually correlated. The objective of this work is to develop a signal-combining system optimized to account for the mutual correlations between these noise processes. The set of optimum combining weight coefficients that maximizes the combined signal SNR in the correlated noises environment is determined. These optimum weights depend on unknown signal and noise covariance parameters. A maximum-likelihood approach is developed to estimate these unknown parameters to obtain estimates of the optimum weight coefficients based on residual carrier signal samples. The actual combined signal SNR using the estimated weight coefficients is derived and shown to converge to the maximum achievable SNR as the number of signal samples increases. These results are also verified by simulation. A numerical example shows a significant improvement in SNR performance can be obtained, especially when the amount of correlation increases.

Liang, R.; Suen, P. H.; Tan, H. H.

1996-01-01

19

Radiation signal processing system  

SciTech Connect

A gamma ray scintillation camera generating (X,y) spatial coordinate and Z energy signals relative to detected radiation events. The system provides for calibration of the camera Z signal response as a function of camera face location. In addition, the camera signals are converted to their digital equivalents subsequent to which the apparent coordinate locations of detected events as determined by the camera are corrected to their true spatial coordinates based upon correction information stored in the system.

Bennett, M.C.; Knoll, G.F.; Strange, D.R.

1981-07-28

20

ECE 468 Digital Signal Processing 1. History  

E-print Network

ECE 468 Digital Signal Processing 1. History: · Digital signal processing has its roots in 17th and Gauss and as new as digital computers and integrated circuits 2. Definition: · Digital signal processing and the processing of these signals. · Digital signal processing and analog signal processing are subfields of signal

Chen, Ying "Ada"

21

Digital signal processing the Tevatron BPM signals  

SciTech Connect

The Beam Position Monitor (TeV BPM) readout system at Fermilab's Tevatron has been updated and is currently being commissioned. The new BPMs use new analog and digital hardware to achieve better beam position measurement resolution. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton measurements. The signals provided by the two ends of the BPM pickups are processed by analog band-pass filters and sampled by 14-bit ADCs at 74.3MHz. A crucial part of this work has been the design of digital filters that process the signal. This paper describes the digital processing and estimation techniques used to optimize the beam position measurement. The BPM electronics must operate in narrow-band and wide-band modes to enable measurements of closed-orbit and turn-by-turn positions. The filtering and timing conditions of the signals are tuned accordingly for the operational modes. The analysis and the optimized result for each mode are presented.

Cancelo, G.; James, E.; Wolbers, S.; /Fermilab

2005-05-01

22

Mechanical Systems Signal Processing  

E-print Network

­171 Multivariate statistics process control for dimensionality reduction in structural assessment L.E. Mujicaa,�, J) for reducing dimensionality in damage identification problem, in particular, detecting and locating impacts in a part of a commercial aircraft wing flap. It is shown that applying MPCA and MPLS is convenient

Verleysen, Michel

23

Discrete Signal Processing on Graphs  

NASA Astrophysics Data System (ADS)

In social settings, individuals interact through webs of relationships. Each individual is a node in a complex network (or graph) of interdependencies and generates data, lots of data. We label the data by its source, or formally stated, we index the data by the nodes of the graph. The resulting signals (data indexed by the nodes) are far removed from time or image signals indexed by well ordered time samples or pixels. DSP, discrete signal processing, provides a comprehensive, elegant, and efficient methodology to describe, represent, transform, analyze, process, or synthesize these well ordered time or image signals. This paper extends to signals on graphs DSP and its basic tenets, including filters, convolution, z-transform, impulse response, spectral representation, Fourier transform, frequency response, and illustrates DSP on graphs by classifying blogs, linear predicting and compressing data from irregularly located weather stations, or predicting behavior of customers of a mobile service provider.

Sandryhaila, Aliaksei; Moura, José M. F.

2013-04-01

24

Signal Processing: Modal Analysis Analytical and Experimental  

E-print Network

Signal Processing: Modal Analysis Analytical and Experimental Modal Analysis #12;Signal Processing: Modal Analysis #12;Signal Processing: Modal Analysis #12;Signal Processing: Modal Analysis 21222312222 f( && && && & & & )N(f)N(x)NN(c)NN(m 11 Ã?Ã?Ã?Ã? General: #12;Signal Processing: Modal Analysis Undamped system: [c] = 0

Rimon, Elon

25

Java Digital Signal Processing Editor  

NSDL National Science Digital Library

Professor Andreas Spanias of Arizona State University has supervised the development of this online digital signal processing (DSP) system simulation utility. This utility has many functions that allow the user to generate various signals, create filters, and analyze the responses. Other functions include Fourier Transforms, convolution, autocorrelation, and several speech processing tools. The interface is well designed and easy to use, and there are plenty of examples and documentation. However, some features are missing from it, such as the ability to print and save. The software is still being improved, though, so these problems might be fixed in the future.

26

Multirate signal processing in Ptolemy  

Microsoft Academic Search

The use of two models of computation, synchronous dataflow (SDF) and dynamic dataflow (DDF), to design and implement signal processing applications with multiple sample rates is discussed. The SDF model is used for synchronous applications. SDF is amenable to compile-time scheduling, and hence is much more efficient at runtime. The design environment, Ptolemy, can simultaneously support multiple models of computation,

J. Buck; S. Ha; E. A. Lee; D. G. Messerschmitt

1991-01-01

27

SAW and optical signal processing  

Microsoft Academic Search

Even in this digital age, SAW and Optical devices remain indispensable analogue signal processing technologies whose operation and success derive from common wave propagation phenomena. In this review I hope to explain why this is so, and will remain so for the foreseeable future. Historically, the development and exploitation of these technologies arose during the Cold War primarily from the

Meirion Lewis

2005-01-01

28

Signal processor for processing ultrasonic receiver signals  

DOEpatents

A signal processor is provided which uses an analog integrating circuit in conjunction with a set of digital counters controlled by a precision clock for sampling timing to provide an improved presentation of an ultrasonic transmitter/receiver signal. The signal is sampled relative to the transmitter trigger signal timing at precise times, the selected number of samples are integrated and the integrated samples are transferred and held for recording on a strip chart recorder or converted to digital form for storage. By integrating multiple samples taken at precisely the same time with respect to the trigger for the ultrasonic transmitter, random noise, which is contained in the ultrasonic receiver signal, is reduced relative to the desired useful signal.

Fasching, George E. (Morgantown, WV)

1980-01-01

29

Signal processing for distributed sensor concept: DISCO  

NASA Astrophysics Data System (ADS)

Distributed Sensor concept - DISCO proposed for multiplication of individual sensor capabilities through cooperative target engagement. DISCO relies on ability of signal processing software to format, to process and to transmit and receive sensor data and to exploit those data in signal synthesis process. Each sensor data is synchronized formatted, Signal-to-Noise Ration (SNR) enhanced and distributed inside of the sensor network. Signal processing technique for DISCO is Recursive Adaptive Frame Integration of Limited data - RAFIL technique that was initially proposed [1] as a way to improve the SNR, reduce data rate and mitigate FPA correlated noise of an individual sensor digital video-signal processing. In Distributed Sensor Concept RAFIL technique is used in segmented way, when constituencies of the technique are spatially and/or temporally separated between transmitters and receivers. Those constituencies include though not limited to two thresholds - one is tuned for optimum probability of detection, the other - to manage required false alarm rate, and limited frame integration placed somewhere between the thresholds as well as formatters, conventional integrators and more. RAFIL allows a non-linear integration that, along with SNR gain, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability [2]. DISCO architecture allows flexible optimization of SNR gain, data rates and noise suppression on sensor's side and limited integration, re-formatting and final threshold on node's side. DISCO with Recursive Adaptive Frame Integration of Limited data may have flexible architecture that allows segmenting the hardware and software to be best suitable for specific DISCO applications and sensing needs - whatever it is air-or-space platforms, ground terminals or integration of sensors network.

Rafailov, Michael K.

2007-04-01

30

Signal processing in eukaryotic chemotaxis  

NASA Astrophysics Data System (ADS)

Unlike inanimate condensed matter, living cells depend upon the detection of chemical signals for their existence. First, we experimentally determined the chemotaxis response of eukaryotic Dictyostelium cells to static folic acid gradients and show that they can respond to gradients as shallow as 0.2% across the cell body. Second, using Shannon's information theory, we showed that the information cells receive about the gradient exceeds the theoretically predicted information at the receptor-ligand binding step, resulting in the violation of the data processing inequality. Finally, we analyzed how eukaryotic cells can affect the gradient signals by secreting enzymes that degrade the signal. We analyzed this effect with a focus on a well described Dictyostelium cAMP chemotaxis system where cAMP signals are affected by an extracellular cAMP phosphodiesterase (PDE) and its inhibitor (PDI). Using a reaction-diffusion model of this set of interactions in the extracellular space, we show that cells can effectively sense much steeper chemical gradients than naively expected (up to a factor of 12). We also found that the rough estimates of experimental PDE and PDI secretion rates are close to the optimal values for gradient sensing as predicted by our model.

Segota, Igor; Rachakonda, Archana; Franck, Carl

2013-03-01

31

Nuclear sensor signal processing circuit  

DOEpatents

An apparatus and method are disclosed for a compact and temperature-insensitive nuclear sensor that can be calibrated with a non-hazardous radioactive sample. The nuclear sensor includes a gamma ray sensor that generates tail pulses from radioactive samples. An analog conditioning circuit conditions the tail-pulse signals from the gamma ray sensor, and a tail-pulse simulator circuit generates a plurality of simulated tail-pulse signals. A computer system processes the tail pulses from the gamma ray sensor and the simulated tail pulses from the tail-pulse simulator circuit. The nuclear sensor is calibrated under the control of the computer. The offset is adjusted using the simulated tail pulses. Since the offset is set to zero or near zero, the sensor gain can be adjusted with a non-hazardous radioactive source such as, for example, naturally occurring radiation and potassium chloride.

Kallenbach, Gene A. (Bosque Farms, NM); Noda, Frank T. (Albuquerque, NM); Mitchell, Dean J. (Tijeras, NM); Etzkin, Joshua L. (Albuquerque, NM)

2007-02-20

32

Experimental studies of optoelectronic signal processors in image and signal processing modes  

NASA Astrophysics Data System (ADS)

Experiments were carried out to demonstrate that the base structure of an optoelectronic signal processor and address blocks can be implemented using existing elements and that high computational efficiency can be achieved with such hardware. Three image and signal processing problems are examined as an example: calculation of a two-dimensional correlation function, processing of signals transmitted by waves, and matrix multiplication. The results obtained are of qualitative nature since the problem of the accuracy of computations is not dealt with.

Gibina, L. A.; Gofman, M. A.; Nezhevenko, E. S.; Fel'Dbush, V. I.

1989-06-01

33

A digital signal processing approach to interpolation  

Microsoft Academic Search

In many digital signal precessing systems, e.g., vacoders, modulation systems, and digital waveform coding systems, it is necessary to alter the sampling rate of a digital signal Thus it is of considerable interest to examine the problem of interpolation of bandlimited signals from the viewpoint of digital signal processing. A frequency dmnain interpretation of the interpolation process, through which it

RONALD W. SCHAFER; LAWRENCE R. RABINER

1973-01-01

34

No-signaling, perfect bipartite dichotomic correlations and local randomness  

SciTech Connect

The no-signaling constraint on bi-partite correlations is reviewed. It is shown that in order to obtain non-trivial Bell-type inequalities that discern no-signaling correlations from more general ones, one must go beyond considering expectation values of products of observables only. A new set of nontrivial no-signaling inequalities is derived which have a remarkably close resemblance to the CHSH inequality, yet are fundamentally different. A set of inequalities by Roy and Singh and Avis et al., which is claimed to be useful for discerning no-signaling correlations, is shown to be trivially satisfied by any correlation whatsoever. Finally, using the set of newly derived no-signaling inequalities a result with potential cryptographic consequences is proven: if different parties use identical devices, then, once they have perfect correlations at spacelike separation between dichotomic observables, they know that because of no-signaling the local marginals cannot but be completely random.

Seevinck, M. P. [Institute for Mathematics, Astrophysics and Particle Physics, Faculty of Science and Centre for the History of Philosophy and Science, Faculty of Philosophy, Radboud University Nijmegen (Netherlands)

2011-03-28

35

Signal Processing: Modal Analysis Experimental Modal Analysis  

E-print Network

Signal Processing: Modal Analysis Experimental Modal Analysis Conduct test excitation A j H = +- = +- = = 22222 1 2 #12;Signal Processing: Modal Analysis kririkr rrr ikv rrrr krir N r ik A j A j H = +- = +- = = 22222 1 2 #12;Signal Processing: Modal Analysis SDOF - Peak method Hik = ]/2

Rimon, Elon

36

Array signal processing for a wireless MEM sensor network  

Microsoft Academic Search

We first review the high-level signal processing architecture of a wireless MEM sensor system for source detection, signal enhancement, localization, and identification. A blind beamformer using only the measured data of randomly distributed sensors to form a sample correlation matrix is proposed. The maximum power collection criterion is used to obtain array weights from the dominant eigenvector of the sample

K. Yao; R. E. Hudson; C. W. Reed; D. Chen; T. L. Tung; F. Lorenzelli

1998-01-01

37

Signal Processing for Phased Array Feeds in Radio Astronomical Telescopes  

Microsoft Academic Search

Relative to traditional waveguide feeds, phased array feeds (PAFs) for radio telescopes can increase the instrument field of view and sky survey speed. Unique challenges associated with PAF observations, including extremely low signal levels, long-term system gain stability requirements, spatially correlated noise due to mutual coupling, and tight beamshape tolerances, require the development of new array signal processing techniques for

Brian D. Jeffs; Karl F. Warnick; Jonathan Landon; Jacob Waldron; David Jones; J. Richard Fisher; Roger D. Norrod

2008-01-01

38

Performance of diversely polarized antenna arrays for correlated signals  

Microsoft Academic Search

The performance of direction finding systems in a correlated signal environment utilizing diversely polarized antenna arrays is investigated. The Cramer-Rao bound (CRB) is used to evaluate the accuracy of the estimated directions of arrival (DOAs). Compact closed form formulas are presented for the CRB corresponding to the joint estimation of the DOAs, signal covariance matrix, signal polarization parameters, and noise

Benjamin Friedlander; ANTHONY J. WEISS

1992-01-01

39

Processing Aftershock Sequences Using Waveform Correlation  

NASA Astrophysics Data System (ADS)

For most event monitoring systems, the objective is to keep up with the flow of incoming data, producing a bulletin with some modest, relatively constant, time delay after present time, often a period of a few hours or less. Because the association problem scales exponentially and not linearly with the number of detections, a dramatic increase in seismicity due to an aftershock sequence can easily cause the bulletin delay time to increase dramatically. In some cases, the production of a bulletin may cease altogether, until the automatic system can catch up. For a nuclear monitoring system, the implications of such a delay could be dire. Given the expected similarity between a mainshock and aftershocks, it has been proposed that waveform correlation may provide a powerful means to simultaneously increase the efficiency of processing aftershock sequences, while also lowering the detection threshold and improving the quality of the event solutions. However, many questions remain unanswered. What are the key parameters for achieving the best correlations between waveforms (window length, filtering, etc.), and are they sequence-dependent? What is the overall percentage of similar events in an aftershock sequence, i.e. what is the maximum level of efficiency that a waveform correlation could be expected to achieve? Finally, how does this percentage of events vary among sequences? Using data from the aftershock sequence for the December 26, 2004 Mw 9.1 Sumatra event, we investigate these issues by building and testing a prototype waveform correlation event detection system that automatically expands its library of known events as new signatures are indentified in the aftershock sequence (by traditional signal detection and event processing). Our system tests all incoming data against this dynamic library, thereby identify any similar events before traditional processing takes place. In the region surrounding the Sumatra event, the NEIC EDR contains 4997 events in the 9 months following the mainshock, and only 265 events during the same period for the previous year, so this sequence represents a formidable challenge for any automatic processing system. Preliminary results suggest that a waveform correlation-based system can detect on the order of 10% or more of the aftershocks for this event. Results published in the recent literature suggest that significantly larger proportions may be achievable for other aftershock sequences with smaller fault ruptures; we investigate and report encouraging results from one such sequence. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04- 94AL85000.

Resor, M. E.; Procopio, M. J.; Young, C. J.; Carr, D. B.

2008-12-01

40

998 IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING, VOL. 2, NO. 6, DECEMBER 2008 Canonical Correlation Analysis for Feature-Based  

E-print Network

brain networks and changes due to disease. We propose a data fusion scheme at the feature level using Correlation Analysis for Feature-Based Fusion of Biomedical Imaging Modalities and Its Application with an independent component analysis based fusion method, joint-ICA that has proven useful for such a study and note

Adali, Tulay

41

Digital Signal Processing Based Biotelemetry Receivers  

NASA Technical Reports Server (NTRS)

This is an attempt to develop a biotelemetry receiver using digital signal processing technology and techniques. The receiver developed in this work is based on recovering signals that have been encoded using either Pulse Position Modulation (PPM) or Pulse Code Modulation (PCM) technique. A prototype has been developed using state-of-the-art digital signal processing technology. A Printed Circuit Board (PCB) is being developed based on the technique and technology described here. This board is intended to be used in the UCSF Fetal Monitoring system developed at NASA. The board is capable of handling a variety of PPM and PCM signals encoding signals such as ECG, temperature, and pressure. A signal processing program has also been developed to analyze the received ECG signal to determine heart rate. This system provides a base for using digital signal processing in biotelemetry receivers and other similar applications.

Singh, Avtar; Hines, John; Somps, Chris

1997-01-01

42

Analog Signal Correlating Using an Analog-Based Signal Conditioning Front End  

NASA Technical Reports Server (NTRS)

This innovation is capable of correlating two analog signals by using an analog-based signal conditioning front end to hard-limit the analog signals through adaptive thresholding into a binary bit stream, then performing the correlation using a Hamming "similarity" calculator function embedded in a one-bit digital correlator (OBDC). By converting the analog signal into a bit stream, the calculation of the correlation function is simplified, and less hardware resources are needed. This binary representation allows the hardware to move from a DSP where instructions are performed serially, into digital logic where calculations can be performed in parallel, greatly speeding up calculations.

Prokop, Norman; Krasowski, Michael

2013-01-01

43

Optimal Correlation Filters for Images with Signal-Dependent Noise  

NASA Technical Reports Server (NTRS)

We address the design of optimal correlation filters for pattern detection and recognition in the presence of signal-dependent image noise sources. The particular examples considered are film-grain noise and speckle. Two basic approaches are investigated: (1) deriving the optimal matched filters for the signal-dependent noise models and comparing their performances with those derived for traditional signal-independent noise models and (2) first nonlinearly transforming the signal-dependent noise to signal-independent noise followed by the use of a classical filter matched to the transformed signal. We present both theoretical and computer simulation results that demonstrate the generally superior performance of the second approach in terms of the correlation peak signal-to-noise ratio.

Downie, John D.; Walkup, John F.

1994-01-01

44

COMPILING DATAFLOW PROGRAMS FOR DIGITAL SIGNAL PROCESSING  

E-print Network

1 Abstract COMPILING DATAFLOW PROGRAMS FOR DIGITAL SIGNAL PROCESSING by Shuvra Shikhar processing algorithms. The main property of this model is that the number of data values produced SDF-based graphical programs for embedded signal processing appli- cations into efficient uniprocessor

Bhattacharyya, Shuvra S.

45

Signal processing and analyzing works of art  

NASA Astrophysics Data System (ADS)

In examining paintings, art historians use a wide variety of physico-chemical methods to determine, for example, the paints, the ground (canvas primer) and any underdrawing the artist used. However, the art world has been little touched by signal processing algorithms. Our work develops algorithms to examine x-ray images of paintings, not to analyze the artist's brushstrokes but to characterize the weave of the canvas that supports the painting. The physics of radiography indicates that linear processing of the x-rays is most appropriate. Our spectral analysis algorithms have an accuracy superior to human spot-measurements and have the advantage that, through "short-space" Fourier analysis, they can be readily applied to entire x-rays. We have found that variations in the manufacturing process create a unique pattern of horizontal and vertical thread density variations in the bolts of canvas produced. In addition, we measure the thread angles, providing a way to determine the presence of cusping and to infer the location of the tacks used to stretch the canvas on a frame during the priming process. We have developed weave matching software that employs a new correlation measure to find paintings that share canvas weave characteristics. Using a corpus of over 290 paintings attributed to Vincent van Gogh, we have found several weave match cliques that we believe will refine the art historical record and provide more insight into the artist's creative processes.

Johnson, Don H.; Johnson, C. Richard, Jr.; Hendriks, Ella

2010-08-01

46

A signal oriented stream processing system for pipeline monitoring  

E-print Network

In this thesis, we develop SignalDB, a framework for composing signal processing applications from primitive stream and signal processing operators. SignalDB allows the user to focus on the signal processing task and avoid ...

Tokmouline, Timur

2006-01-01

47

Research Report Neural activity during social signal perception correlates with  

E-print Network

Research Report Neural activity during social signal perception correlates with self components. Cognitive empathy includes mentalizing skills such as perspective-taking. Affective empathy in daily life. Participants viewed social scenes in which the shift of direction of attention

48

Optical signal processing with magnetostatic waves  

NASA Astrophysics Data System (ADS)

Magnetooptical devices employing the Bragg diffraction of light by magnetostatic waves (MSWs) may furnish large time-bandwidth processing of optical signals at 1-20 GHz. Attention is presently given to a thin film integrated device in which the interacting MSW and guided optical wave both propagate in a common ferrite layer. It is noted that shape factor demagnetization effects must be avoided. The underlying MSW-optical interaction theory is presented, together with expressions for optical diffraction efficiency as a function of MSW parameters. TE - TM mode conversion, induced by MSWs in YIG thin films, suggest that high performance integrated devices are feasible, with such potential applications as spectrum analyzers, convolvers/correlators, deflectors, nonreciprocal optical isolators, and tunable narrowband optical filters with higher operating frequencies and diffraction efficiencies than conventional acoustooptical devices.

Fisher, A. D.

49

High-speed and reconfigurable all-optical signal processing for phase and amplitude modulated signals  

NASA Astrophysics Data System (ADS)

Technology has empowered people in all walks of life to generate, store, and communicate enormous amounts of data. Recent technological advances in high-speed backbone data networks, together with the growing trend toward bandwidth-demanding applications such as data and video sharing, cloud computing, and data collection systems, have created a need for higher capacities in signal transmission and signal processing. Optical communication systems have long benefited from the large bandwidth of optical signals (beyond tera-hertz) to transmit information. Through the use of optical signal processing techniques, this Ph.D. dissertation explores the potential of very-high-speed optics to assist electronics in processing huge amounts of data at high speeds. Optical signal processing brings together various fields of optics and signal processing---nonlinear devices and processes, analog and digital signals, and advanced data modulation formats---to achieve high-speed signal processing functions that can potentially operate at the line rate of fiber optic communications. Information can be encoded in amplitude, phase, wavelength, polarization, and spatial features of an optical wave to achieve high-capacity transmission. Many advances in the key enabling technologies have led to recent research in optical signal processing for digital signals that are encoded in one or more of these dimensions. Optical Kerr nonlinearities have femto-second response times that have been exploited for fast processing of optical signals. Various optical nonlinearities and chromatic dispersions have enabled key sub-system applications such as wavelength conversion, multicasting, multiplexing, demultiplexing, and tunable optical delays. In this Ph.D. dissertation, we employ these recent advances in the enabling technologies for high-speed optical signal processing to demonstrate various techniques that can process phase- and amplitude-encoded optical signals at the line rate of optics. We use nonlinear media, such as highly nonlinear fiber, periodically poled lithium niobate, and semiconductor optical amplifiers, for nonlinear mixing of optical signals. We propose and experimentally demonstrate a novel, fully tunable optical tapped-delay-line that is a key building block for signal processing functions. Applications such as finite impulse response filtering, equalization, correlation (pattern recognition), discrete Fourier transform, digital-to-analog conversion, and flexible optical signal conversion and generation are shown. The phase- and amplitude-preserving nature of the demonstrated techniques, together with their wide-tuning range, allows for processing of optical signals that carry different modulation formats with different data rates. The reconfigurability may apply to future optical networks that carry heterogeneous traffic with different modulation formats and baud rates.

Khaleghi, Salman

50

Using many-core hardware to correlate radio astronomy signals  

Microsoft Academic Search

A recent development in radio astronomy is to replace traditional dishes withmany small antennas. The signals are combined toform one large, virtual telescope. The enormous data streams are cross- correlated to filter out noise. This is especially challenging, since the computational demands grow quadratically with the number of data streams. Moreover, the correlator is not only computationally intensive, but also

Rob V. Van Nieuwpoort; John W. Romein

2009-01-01

51

Bistatic SAR: Signal Processing and Image Formation.  

SciTech Connect

This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (SAR) hardware built for the NCNS Bistatic SAR project to a final bistatic SAR image. In general, the process steps herein are applicable to bistatic SAR signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013 on Kirtland Air Force Base, New Mexico.

Wahl, Daniel E.; Yocky, David A.

2014-10-01

52

CONTROL, COMMUNICATION & SIGNAL PROCESSING (CCSP)  

E-print Network

student, this course is for you! In EGN 1935 you'll learn about robots and experiment with sensorsS cells, sonar and cameras) electronic circuits (including switch circuits, LED circuits, voltage divider. Piezo speakers, sound generation, digital signals, sampled data, sampling frequency, sonar. 8. Cameras

Liebling, Michael

53

Correlation Spectroscopy of Minor Species: Signal Purification and Distribution Analysis  

SciTech Connect

We are performing experiments that use fluorescence resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) to monitor the movement of an individual donor-labeled sliding clamp protein molecule along acceptor-labeled DNA. In addition to the FRET signal sought from the sliding clamp-DNA complexes, the detection channel for FRET contains undesirable signal from free sliding clamp and free DNA. When multiple fluorescent species contribute to a correlation signal, it is difficult or impossible to distinguish between contributions from individual species. As a remedy, we introduce ''purified FCS'' (PFCS), which uses single molecule burst analysis to select a species of interest and extract the correlation signal for further analysis. We show that by expanding the correlation region around a burst, the correlated signal is retained and the functional forms of FCS fitting equations remain valid. We demonstrate the use of PFCS in experiments with DNA sliding clamps. We also introduce ''single molecule FCS'', which obtains diffusion time estimates for each burst using expanded correlation regions. By monitoring the detachment of weakly-bound 30-mer DNA oligomers from a single-stranded DNA plasmid, we show that single molecule FCS can distinguish between bursts from species that differ by a factor of 5 in diffusion constant.

Laurence, T A; Kwon, Y; Yin, E; Hollars, C; Camarero, J A; Barsky, D

2006-06-21

54

Digital signal processing techniques for high accuracy ultrasonic range measurements  

Microsoft Academic Search

Several digital signal processing (DSP) methods are analyzed and compared with respect to the expected errors for an ultrasonic range measurement arrangement. These include L1, L2 norms and correlation with different approaches for envelope extraction. The influence of different factors such as signal-to-noise ratio (SNR), sampling frequency, and digitizing resolution on measurement errors is analyzed using a synthetic approach through

M. Parrilla; J. J. Anaya; C. Fritsch

1991-01-01

55

Optical signal processing for surveillance  

NASA Astrophysics Data System (ADS)

Recent progress toward multichannel implementation of a time-integrating, acousto-optic Fourier transforming device is described. Various multichannel schemes are assessed, and advantages and disadvantages for scheme given. A laboratory multichannel demonstration has been carried out successfully. It is shown that Fourier transformation of a simulated Gemini signal can be readily obtained. A special A-O demultiplexer is proposed to handle the data format proposed by Aerojet for the focal-plane detector array. Recommendations for future tasks are given.

Lee, J. N.; Lin, S. S. C.

1984-04-01

56

Optical Signal Processing Techniques for Signal Regeneration and Digital Logic  

Microsoft Academic Search

This chapter presents recent developments in optical signal processing techniques and digital logic. The first section focuses\\u000a on techniques to obtain key functionalities as signal regeneration and wavelength conversion exploiting nonlinear effects\\u000a in high nonlinear fibres and semiconductor optical amplifiers. The second section covers techniques for clock recovery and\\u000a retiming at high-speed transmission up to 320 Gb\\/s. In addition a

Karin Ennser; Slavisa Aleksic; Franco Curti; Davide Massimiliano Forin; Michael Galili; M. Karasek; L. K. Oxenløwe; Francesca Parmigiani; Periklis Petropoulos; R. Slav'ik

2009-01-01

57

Investigating correlation of oscillatory behaviour between two signals using wavelets  

NASA Astrophysics Data System (ADS)

Wavelet analysis is becoming more commonplace given the augmentation of computational power over recent decades. Consequently, the use of such techniques is increasing within the geosciences, particularly when investigating the presence of any oscillatory behaviour contained within signals. As such, the ability to investigate correlation of oscillations present between two separate signals has become increasingly necessary. We have developed a technique combining the continuous wavelet transform (CWT) with Spearman's rank correlation coefficient analysis on two signals of equal length and frequency. This is performed by calculating the CWT on the two signals, extracting coefficients from the generated data at each separate scale, followed by computation of correlation between each extracted scale. The result is a clear graphical depiction of links, if any, and strength between oscillations present, with the ability to determine whether signals are in or out of phase with one another. In comparison with alternate approaches, e.g., wavelet coherence, we establish that this technique is simpler to implement and interpret, providing far clearer visual identification of inter-series relationships. We demonstrate this fact using our developed simple and easy-to-use Matlab® code which rapidly executes this procedure, producing two and three dimensional images, with the major emphasis on simplicity of the technique. Subsequently we exhibit the approach on artificially generated signals with known periodicities which are also infused with random noise. Following this the utility of our technique on a number of volcanic, geochemical and climatic signals which contain periodic behaviour is illustrated.

Pering, Tom D.; Tamburello, Giancarlo; McGonigle, Andrew J. S.; Hanna, Edward; Aiuppa, Alessandro

2014-05-01

58

Digital Signal Processing in Acoustics--Part 2.  

ERIC Educational Resources Information Center

Reviews the potential of a data acquisition system for illustrating the nature and significance of ideas in digital signal processing. Focuses on the fast Fourier transform and the utility of its two-channel format, emphasizing cross-correlation and its two-microphone technique of acoustic intensity measurement. Includes programing format. (ML)

Davies, H.; McNeill, D. J.

1986-01-01

59

Digital signal processing in microwave radiometers  

NASA Technical Reports Server (NTRS)

A microprocessor based digital signal processing unit has been proposed to replace analog sections of a microwave radiometer. A brief introduction to the radiometer system involved and a description of problems encountered in the use of digital techniques in radiometer design are discussed. An analysis of the digital signal processor as part of the radiometer is then presented.

Lawrence, R. W.; Stanley, W. D.; Harrington, R. F.

1980-01-01

60

Blind deconvolution through digital signal processing  

Microsoft Academic Search

This paper addresses the problem of deconvolving two signals when both are unknown. The authors call this problem blind deconvolution. The discussion develops two related solutions which can be applied through digital signal processing in certain practical cases. The case of reverberated and resonated sound forms the center of the development. The specific problem of restoring old acoustic recordings provides

T. M. Cannon; R. B. Ingebretsen

1975-01-01

61

Photoacoustic correlation signal-to-noise ratio enhancement by coherent averaging and optical waveform optimization.  

PubMed

Photoacoustic (PA) imaging of biological tissues using laser diodes instead of conventional Q-switched pulsed systems provides an attractive alternative for biomedical applications. However, the relatively low energy of laser diodes operating in the pulsed regime, results in generation of very weak acoustic waves, and low signal-to-noise ratio (SNR) of the detected signals. This problem can be addressed if optical excitation is modulated using custom waveforms and correlation processing is employed to increase SNR through signal compression. This work investigates the effect of the parameters of the modulation waveform on the resulting correlation signal and offers a practical means for optimizing PA signal detection. The advantage of coherent signal averaging is demonstrated using theoretical analysis and a numerical model of PA generation. It was shown that an additional 5-10 dB of SNR can be gained through waveform engineering by adjusting the parameters and profile of optical modulation waveforms. PMID:24182151

Telenkov, Sergey A; Alwi, Rudolf; Mandelis, Andreas

2013-10-01

62

Fatigue independent amplitude-frequency correlations in EMG signals  

E-print Network

In order to assess fatigue independent amplitude-frequency correlations in EMG signals we asked nineteen male subjects to perform a series of isometric muscular contractions by extensors of the knee joint. Different amplitudes of the signal were due to randomly varying both the joint moment and the overall amplification factor of the EMG apparatus. Mean and median frequency, RMS and mean absolute value were calculated for every combination of joint moment and amplification at the original sampling rate of 5 kHz and at several simulated lower sampling rates. Negative Spearman and Kendall amplitude-frequency correlation coefficients were found, and they were more pronounced at high sampling rates.

Siemienski, A; Klajner, P; Siemienski, Adam; Kebel, Alicja; Klajner, Piotr

2006-01-01

63

Stochastic Search for Signal Processing Algorithm Optimization  

E-print Network

large number of different but mathematically equivalent formulas. When these formulas are implemented be represented by mathematical formulas and a single signal processing algorithm can be represented by many different, but mathematically equivalent, formulas (Auslander et al., 1996). Interestingly, when

64

Correlating Radio Astronomy Signals with Many-Core Hardware  

Microsoft Academic Search

A recent development in radio astronomy is to replace traditional dishes with many small antennas. The signals are combined\\u000a to form one large, virtual telescope. The enormous data streams are cross-correlated to filter out noise. This is especially\\u000a challenging, since the computational demands grow quadratically with the number of data streams. Moreover, the correlator\\u000a is not only computationally intensive, but

Rob V. van Nieuwpoort; John W. Romein

2011-01-01

65

RSFQ Baseband Digital Signal Processing  

NASA Astrophysics Data System (ADS)

Ultra fast switching speed of superconducting digital circuits enable realization of Digital Signal Processors with performance unattainable by any other technology. Based on rapid-single-flux technology (RSFQ) logic, these integrated circuits are capable of delivering high computation capacity up to 30 GOPS on a single processor and very short latency of 0.1ns. There are two main applications of such hardware for practical telecommunication systems: filters for superconducting ADCs operating with digital RF data and recursive filters at baseband. The later of these allows functions such as multiuser detection for 3G WCDMA, equalization and channel precoding for 4G OFDM MIMO, and general blind detection. The performance gain is an increase in the cell capacity, quality of service, and transmitted data rate. The current status of the development of the RSFQ baseband DSP is discussed. Major components with operating speed of 30GHz have been developed. Designs, test results, and future development of the complete systems including cryopackaging and CMOS interface are reviewed.

Herr, Anna Yurievna

66

Novel sonar signal processing tool using Shannon entropy  

SciTech Connect

Traditionally, conventional signal processing extracts information from sonar signals using amplitude, signal energy or frequency domain quantities obtained using spectral analysis techniques. The object is to investigate an alternate approach which is entirely different than that of traditional signal processing. This alternate approach is to utilize the Shannon entropy as a tool for the processing of sonar signals with emphasis on detection, classification, and localization leading to superior sonar system performance. Traditionally, sonar signals are processed coherently, semi-coherently, and incoherently, depending upon the a priori knowledge of the signals and noise. Here, the detection, classification, and localization technique will be based on the concept of the entropy of the random process. Under a constant energy constraint, the entropy of a received process bearing finite number of sample points is maximum when hypothesis H{sub 0} (that the received process consists of noise alone) is true and decreases when correlated signal is present (H{sub 1}). Therefore, the strategy used for detection is: (I) Calculate the entropy of the received data; then, (II) compare the entropy with the maximum value; and, finally, (III) make decision: H{sub 1} is assumed if the difference is large compared to pre-assigned threshold and H{sub 0} is otherwise assumed. The test statistics will be different between entropies under H{sub 0} and H{sub 1}. Here, we shall show the simulated results for detecting stationary and non-stationary signals in noise, and results on detection of defects in a Plexiglas bar using an ultrasonic experiment conducted by Hughes. {copyright} {ital 1996 American Institute of Physics.}

Quazi, A.H. [Code 3122, Naval Undersea Warfare Center, Detachment, New London, Connecticut 06320 (United States)

1996-06-01

67

Process Correlation Analysis Model for Process Improvement Identification  

PubMed Central

Software process improvement aims at improving the development process of software systems. It is initiated by process assessment identifying strengths and weaknesses and based on the findings, improvement plans are developed. In general, a process reference model (e.g., CMMI) is used throughout the process of software process improvement as the base. CMMI defines a set of process areas involved in software development and what to be carried out in process areas in terms of goals and practices. Process areas and their elements (goals and practices) are often correlated due to the iterative nature of software development process. However, in the current practice, correlations of process elements are often overlooked in the development of an improvement plan, which diminishes the efficiency of the plan. This is mainly attributed to significant efforts and the lack of required expertise. In this paper, we present a process correlation analysis model that helps identify correlations of process elements from the results of process assessment. This model is defined based on CMMI and empirical data of improvement practices. We evaluate the model using industrial data. PMID:24977170

Park, Sooyong

2014-01-01

68

Process correlation analysis model for process improvement identification.  

PubMed

Software process improvement aims at improving the development process of software systems. It is initiated by process assessment identifying strengths and weaknesses and based on the findings, improvement plans are developed. In general, a process reference model (e.g., CMMI) is used throughout the process of software process improvement as the base. CMMI defines a set of process areas involved in software development and what to be carried out in process areas in terms of goals and practices. Process areas and their elements (goals and practices) are often correlated due to the iterative nature of software development process. However, in the current practice, correlations of process elements are often overlooked in the development of an improvement plan, which diminishes the efficiency of the plan. This is mainly attributed to significant efforts and the lack of required expertise. In this paper, we present a process correlation analysis model that helps identify correlations of process elements from the results of process assessment. This model is defined based on CMMI and empirical data of improvement practices. We evaluate the model using industrial data. PMID:24977170

Choi, Su-jin; Kim, Dae-Kyoo; Park, Sooyong

2014-01-01

69

Haotic, Fractal, and Nonlinear Signal Processing. Proceedings  

SciTech Connect

These proceedings include papers presented at the Third Technical Conference on Nonlinear Dynamics and Full{minus}Spectrum Processing held in Mystic, Connecticut. The Conference focus was on the latest advances in chaotic, fractal and nonlinear signal processing methods. Topics of discussion covered in the Conference include: mathematical frontiers; predictability and control of chaos, detection and classification with applications in acoustics; advanced applied signal processing methods(linear and nonlinear); stochastic resonance; machinery diagnostics; turbulence; geophysics; medicine; and recent novel approaches to modeling nonlinear systems. There were 58 papers in the conference and all have been abstracted for the Energy Science and Technology database. (AIP)

Katz, R.A. [Naval Undersea Warfare Center, Newport, RI (United States)

1996-10-01

70

Correlated activity supports efficient cortical processing  

PubMed Central

Visual recognition is a computational challenge that is thought to occur via efficient coding. An important concept is sparseness, a measure of coding efficiency. The prevailing view is that sparseness supports efficiency by minimizing redundancy and correlations in spiking populations. Yet, we recently reported that “choristers”, neurons that behave more similarly (have correlated stimulus preferences and spontaneous coincident spiking), carry more generalizable object information than uncorrelated neurons (“soloists”) in macaque inferior temporal (IT) cortex. The rarity of choristers (as low as 6% of IT neurons) indicates that they were likely missed in previous studies. Here, we report that correlation strength is distinct from sparseness (choristers are not simply broadly tuned neurons), that choristers are located in non-granular output layers, and that correlated activity predicts human visual search efficiency. These counterintuitive results suggest that a redundant correlational structure supports efficient processing and behavior. PMID:25610392

Hung, Chou P.; Cui, Ding; Chen, Yueh-peng; Lin, Chia-pei; Levine, Matthew R.

2015-01-01

71

Modeling signalized intersection safety with corridor-level spatial correlations.  

PubMed

Intersections in close spatial proximity along a corridor should be considered as correlated due to interacted traffic flows as well as similar road design and environmental characteristics. It is critical to incorporate this spatial correlation for assessing the true safety impacts of risk factors. In this paper, several Bayesian models were developed to model the crash data from 170 signalized intersections in the state of Florida. The safety impacts of risk factors such as geometric design features, traffic control, and traffic flow characteristics were evaluated. The Poisson and Negative Binomial Bayesian models with non-informative priors were fitted but the focus is to incorporate spatial correlations among intersections. Two alternative models were proposed to capture this correlation: (1) a mixed effect model in which the corridor-level correlation is incorporated through a corridor-specific random effect and (2) a conditional autoregressive model in which the magnitude of correlations is determined by spatial distances among intersections. The models were compared using the Deviance Information Criterion. The results indicate that the Poisson spatial model provides the best model fitting. Analysis of the posterior distributions of model parameters indicated that the size of intersection, the traffic conditions by turning movement, and the coordination of signal phase have significant impacts on intersection safety. PMID:19887148

Guo, Feng; Wang, Xuesong; Abdel-Aty, Mohamed A

2010-01-01

72

Improved Algorithms for Nanopore Signal Processing  

E-print Network

Nanopore resistive pulse techniques are based on analysis of current or voltage spikes in the recorded signal. These spikes result from translocation of nanometer sized analytes through a nanopore. The most important information that needs to be extracted is the duration, amplitude and number of the translocation spikes. The recorded signal is usually considerably noisy, with a huge baseline drift and hundreds of translocation spikes. Thus, incorporation of suitable signal processing algorithms is necessary for correct and fast detection of all the translocation spikes and to accurately measure their amplitude and duration. Generally, low-pass filtering is used for denoising, averaging is used for baseline detection, and thresholding is used for spike detection and measurement. Here we present novel algorithms and specifically developed software for nanopore signal processing that are significantly improving the accuracy of the nanopore measurements. It includes an improved method for baseline removing, an op...

Arjmandi, Nima; Lagae, Liesbet; Borghs, Gustaaf

2012-01-01

73

Optical signal processing for wireless transmission  

NASA Astrophysics Data System (ADS)

Millimeter-wave bands are attracting attention because of the availability of wideband for high-speed transmission. However, due to the limitation of the performance of electric signal processing, it is rather difficult to modulate and demodulate millimeter-wave signals with high-speed baseband modulation. In this paper, we describe optical signal processing for high-speed modulation of millimeter-wave, based on high-speed and precise lightwave control. In optical fiber communication systems, various types of modulation formats, such as quadrature-amplitude-modulation, are reported to achieve high-speed transmission. Optical two-tone signals can be converted into millimeter-wave signals by using high-speed photodetectors. This technique can be used for distribution of stable reference signals in large-scale antenna arrays for radio astronomy. By using the millimeter-wave signal generation technique and the optical advanced modulation formats, we can achieve high-speed modulation of millimeter-waves, where the carrier frequency and bit rate can be over 90GHz and 40Gb/s, respectively.

Kawanishi, Tetsuya

2012-01-01

74

Correlation Resonance Generated by Coupled Enzymatic Processing  

PubMed Central

A major challenge for systems biology is to deduce the molecular interactions that underlie correlations observed between concentrations of different intracellular molecules. Although direct explanations such as coupled transcription or direct protein-protein interactions are often considered, potential indirect sources of coupling have received much less attention. Here we show how correlations can arise generically from a posttranslational coupling mechanism involving the processing of multiple protein species by a common enzyme. By observing a connection between a stochastic model and a multiclass queue, we obtain a closed form expression for the steady-state distribution of the numbers of molecules of each protein species. Upon deriving explicit analytic expressions for moments and correlations associated with this distribution, we discover a striking phenomenon that we call correlation resonance: for small dilution rate, correlations peak near the balance-point where the total rate of influx of proteins into the system is equal to the maximum processing capacity of the enzyme. Given the limited number of many important catalytic molecules, our results may lead to new insights into the origin of correlated behavior on a global scale. PMID:21081064

Mather, William H.; Cookson, Natalie A.; Hasty, Jeff; Tsimring, Lev S.; Williams, Ruth J.

2010-01-01

75

Bring Signal Processing to the Public IEEE SIGNAL PROCESSING MAGAZINE [6] MARCH 2008  

E-print Network

processing is a stealth technolo- gy." The words signal processing are not part of the popular lexicon even though it is a major technology underlying many of the modern-day innovations-- cell phones, digital

Moura, José

76

Signal Processing Methods Monitor Cranial Pressure  

NASA Technical Reports Server (NTRS)

Dr. Norden Huang, of Goddard Space Flight Center, invented a set of algorithms (called the Hilbert-Huang Transform, or HHT) for analyzing nonlinear and nonstationary signals that developed into a user-friendly signal processing technology for analyzing time-varying processes. At an auction managed by Ocean Tomo Federal Services LLC, licenses of 10 U.S. patents and 1 domestic patent application related to HHT were sold to DynaDx Corporation, of Mountain View, California. DynaDx is now using the licensed NASA technology for medical diagnosis and prediction of brain blood flow-related problems, such as stroke, dementia, and traumatic brain injury.

2010-01-01

77

Signal Processing 24 ( 1991) 177-192 On hidden fractal model signal processing*  

E-print Network

Signal Processing 24 ( 1991) 177-192 Else\\ier 177 On hidden fractal model signal processing* Vikram Krishnamurthy, John B. Moore Department qf .$,.srem.s Engineering, Re.rearch School qf Physical .sc[ence.s and Engineering, Auvtrulian Narionai Uniuer.$it]', GPO Bo.r 4, Canberra AC T2601, Australia Shin-Ho Chung Research

Moore, John Barratt

78

Surveillance of industrial processes with correlated parameters  

DOEpatents

A system and method for surveillance of an industrial process. The system and method includes a plurality of sensors monitoring industrial process parameters, devices to convert the sensed data to computer compatible information and a computer which executes computer software directed to analyzing the sensor data to discern statistically reliable alarm conditions. The computer software is executed to remove serial correlation information and then calculate Mahalanobis distribution data to carry out a probability ratio test to determine alarm conditions.

White, Andrew M. (Skokie, IL); Gross, Kenny C. (Bolingbrook, IL); Kubic, William L. (Sante Fe, NM); Wigeland, Roald A. (Olympia Fields, IL)

1996-01-01

79

Surveillance of industrial processes with correlated parameters  

DOEpatents

A system and method for surveillance of an industrial process are disclosed. The system and method includes a plurality of sensors monitoring industrial process parameters, devices to convert the sensed data to computer compatible information and a computer which executes computer software directed to analyzing the sensor data to discern statistically reliable alarm conditions. The computer software is executed to remove serial correlation information and then calculate Mahalanobis distribution data to carry out a probability ratio test to determine alarm conditions. 10 figs.

White, A.M.; Gross, K.C.; Kubic, W.L.; Wigeland, R.A.

1996-12-17

80

Signal Processing Schemes for Doppler Global Velocimetry  

NASA Technical Reports Server (NTRS)

Two schemes for processing signals obtained from the Doppler global velocimeter are described. The analog approach is a simple, real time method for obtaining an RS-170 video signal containing the normalized intensity image. Pseudo colors are added using a monochromatic frame grabber producing a standard NTSC video signal that can be monitored and/or recorded. The digital approach is more complicated, but maintains the full resolution of the acquisition cameras with the capabilities to correct the signal image for pixel sensitivity variations and to remove of background light. Prototype circuits for each scheme are described and example results from the investigation of the vortical flow field above a 75-degree delta wing presented.

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.

1991-01-01

81

Signal processing schemes for Doppler global velocimetry  

NASA Technical Reports Server (NTRS)

Two schemes for processing signals obtained from the Doppler global velocimeter are described. The analog approach is a simple, real-time method for obtaining an RS-170 video signal containing the normalized intensity image. Pseudocolors are added using a monochromatic frame grabber producing a standard NTSC video signal that can be monitored and/or recorded. The digital approach is more complicated, but maintains the full resolution of the acquisition cameras with the ability to correct the signal image for pixel sensitivity variations and to remove background light. Prototype circuits for each scheme are described, and example results from the investigation of the vortical flow field above a 75-deg delta wing are presented.

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.

1991-01-01

82

Processing of the laser Doppler velocimeter signals  

NASA Technical Reports Server (NTRS)

The laser Doppler velocimeter (LDV) is a probeless technique that provides a remote measurement of mean and fluctuating velocities. The measurement is actually obtained from small particles embedded in the flow which scatter light from an illuminating laser beam interference pattern. A portion of this scattered light is collected by a photomultiplier which yields an electronic signal whose frequency is directly proportional to the velocity of the small particles. The purpose of this paper is to describe and critically compare three techniques most used to process this electronic signal. These techniques are: (1) spectrum analyzer - a frequency scanning filter (frequency domain instrument), (2) wide-band frequency tracker - a frequency lock loop (frequency domain instrument), and (3) high-speed frequency counter - an interval timer (time domain instrument). The study determines the ability of each technique to process the LDV signal and yield velocity data to be used in determining the flow characteristics.

Meyers, J. F.; Feller, W. V.

1973-01-01

83

Visual signal processing, speechreading, and related issues  

NASA Astrophysics Data System (ADS)

People with hearing loss make use of visual speech cues to supplement the impoverished speech signal. This process, known as speechreading (or lipreading) can be very effective because of the complementary nature of auditory and visual speech cues. Despite the importance of visual speech cues (for both normal-hearing and hearing-impaired people) research on the visual characteristics of speech has lagged behind research on the acoustic characteristics of speech. The field of acoustic phonetics benefited substantially from the availability of powerful techniques for acoustic signal analysis. The substantial, recent advances in optical signal processing have opened up new vistas for visual speech analysis analogous to the way technological innovation revolutionized the field of acoustic phonetics. This paper describes several experiments in the emerging field of optic phonetics.

Levitt, Harry

2003-06-01

84

Digital signal processing method and implementation for pulse laser rangefinder  

Microsoft Academic Search

The laser echo pulses of a pulse laser rangefinder are narrow, weak and low SNR (signal-to-noise ratio) signals. Digital signal processing method was presented for such signals to improve SNR. A digital signal processing circuit of a pulse laser rangefinder was designed, based on DSP (digital signal processor) and CPLD chips. The algorithms of digital filtering, pulse accumulation, target detection

Jianke Li; Baojun Zhao; Linbo Tang; Xiaoxia Zhao

2009-01-01

85

Improvement of Signal-to-noise ratios of surface wave signal obtained through ambient noise correlations  

NASA Astrophysics Data System (ADS)

Spectral whitening has become a widely used preprocessing method in the field of ambient seismic noise. Using two years of noise recordings from an array of European stations, we show that an improvement in the signal-to-noise ratio (SNR) of station-station cross-correlations can be obtained using a different form of spectral whitening. This alternative combines spectral whitening with the processing associated with the spatial autocorrelation (SPAC) method (Aki, 1957). The difference between the two techniques is the order of ensemble averaging and normalization. Spectral whitening involves normalization of the cross-spectrum by the individual power for each time-window and subsequent ensemble averaging. SPAC-processing in turn involves ensemble averaging prior to normalization: the ensemble-averaged cross-spectrum is normalized with respect the ensemble averaged power. The SPAC-method relies on the stationarity of the wavefield. In general, the wavefield is only stationary over relatively short time intervals (Okada, 2003). We therefore explain the increased SNR's with this characteristic of the wavefield. [Aki, 1957] Aki, K., 1957, Space and time spectra of stationary stochastic waves, with special reference to microtremors.: Bulletin of the Earthquake Research Institute, University of Tokyo, 35, 415-457. [Okada, 2003] Okada, H., 2003, The microtremor survey method: Society of Exploration Geophysicists. Geophysical Monograph, No. 12.

Weemstra, Cornelis; Boschi, Lapo; Verbeke, Julie

2013-04-01

86

C Language Algorithms for Digital Signal Processing  

Microsoft Academic Search

The use of the C programming language to construct digital signal-processing (DSP) algorithms for operation on high-performance personal computers is described in a textbook for engineering students. Chapters are devoted to the fundamental principles of DSP, basic C programming techniques, user-interface and disk-storage routines, filtering routines, discrete Fourier transforms, matrix and vector routines, and image-processing routines. Also included is a

Paul M. Embree; Bruce Kimble; James F. Bartram

1991-01-01

87

Very-high-speed optical signal processing  

Microsoft Academic Search

Challenges of next-generation transmission technologies are summarized in the context of creating future terabit-per-second networks. The technologies will be realized through both the separate and combined evolution of inherent lightwave capabilities along with time-, wavelength-, and space-domain optical processing techniques. Optical signal processing techniques in the tens of gigabit per second range for future high-speed transmission systems and broadband networks

SADAKUNI SHIMADA; KIYOSHI NAKAGAWA; MAS ATOSHI SARUWATARI; T. Matsumoto

1993-01-01

88

Displays, memories, and signal processing: A compilation  

NASA Technical Reports Server (NTRS)

Articles on electronics systems and techniques were presented. The first section is on displays and other electro-optical systems; the second section is devoted to signal processing. The third section presented several new memory devices for digital equipment, including articles on holographic memories. The latest patent information available is also given.

1975-01-01

89

Review of biomedical signal and image processing  

PubMed Central

This article is a review of the book “Biomedical Signal and Image Processing” by Kayvan Najarian and Robert Splinter, which is published by CRC Press, Taylor & Francis Group. It will evaluate the contents of the book and discuss its suitability as a textbook, while mentioning highlights of the book, and providing comparison with other textbooks.

2013-01-01

90

MOTOROLA DIGITAL SIGNAL PROCESSING DEVELOPMENT SOFTWARE  

E-print Network

-up, revocable, non-exclusive license to use the software program(s) (SOFTWARE) and documentation (DOCUMENTATION or in part, in any form, of the SOFTWARE and DOCUMENTATION have been destroyed or returned to MOTOROLA. 6MOTOROLA DIGITAL SIGNAL PROCESSING DEVELOPMENT SOFTWARE DSP563CCC MOTOROLA DSP56300 FAMILY

Kutil, Rade

91

Computer Aided Teaching of Digital Signal Processing.  

ERIC Educational Resources Information Center

Describes a microcomputer-based software package developed at the University of Surrey for teaching digital signal processing to undergraduate science and engineering students. Menu-driven software capabilities are explained, including demonstration of qualitative concepts and experimentation with quantitative data, and examples are given of…

Castro, Ian P.

1990-01-01

92

Signal processing and analyzing works of art  

Microsoft Academic Search

In examining paintings, art historians use a wide variety of physico-chemical methods to determine, for example, the paints, the ground (canvas primer) and any underdrawing the artist used. However, the art world has been little touched by signal processing algorithms. Our work develops algorithms to examine x-ray images of paintings, not to analyze the artist's brushstrokes but to characterize the

Don H. Johnson; C. Richard Johnson Jr.; Ella Hendriks

2010-01-01

93

Image resolution improvement: A signal processing approach  

Microsoft Academic Search

High-resolution (HR) images are in demand because they not only give the viewer a pleasing view of the scene but also offer additional details that are important for analysis. Signal processing approach can be used to improve the resolution from several sub pixel shifted low resolution images. The image to be super-resolved is estimated from a set of low resolution

P. S. Shilpashree; K. V. Suresh

2010-01-01

94

Acoustic Signal Processing for Pipe Condition Assessment  

EPA Science Inventory

Unique to prestressed concrete cylinder pipe (PCCP), individual wire breaks create an excitation in the pipe wall that may vary in response to the remaining compression of the pipe core. This project was designed to improve acoustic signal processing for pipe condition assessment...

95

Adaptive signal processing in medical ultrasound beamforming  

Microsoft Academic Search

For over thirty years adaptive beamforming (AB) algorithms have been applied in RADAR and SONAR signal processing. Higher resolution and contrast is attainable using those algorithms at the price of an increased computational load. In this paper we consider four beamformers (BFs): Frost BF, Duvall BF, SSB, and SPOC. These algorithms are well know in the RADAR\\/SONAR literature. We have

Francesco Viola; William F. Walker

2005-01-01

96

Noninvasive BCIs: Multiway Signal-Processing  

E-print Network

optimal functionality and usability.2-6 Why Brain-Computer interfaCes? There are several reasons why BCI, the brain-computer interface neuroscience paradigm allows researchers to develop a new classNoninvasive BCIs: Multiway Signal-Processing Array Decompositions B rain computer interfaces (BCIs

Zhang, Liqing

97

Intelligent processing of ultrasonic signals for process control applications  

SciTech Connect

The authors review here some of the approaches that have been used to apply intelligent, neural-like signal processing procedures to solve a number of acoustic emission (AE) and active ultrasonic (UT) process control measurement problems which can be expected to have important process control applications. Characteristics of these approaches is the use of a set of learning signals from an array of sensors to develop a memory containing prototypical pattern vectors composed of acoustic data and process characteristics. This memory can subsequently be utilized to process signals to optimally recover parameters of the manufacturing process. Approaches applicable for linear and non-linear problems have been developed. For the latter, algorithms implementing a multi-layered, feed-forward neural network or alternatively, a non-parametric, multi-dimensional regression approach called an automatic modeler have been developed. Here they illustrate this modeler by its application to characterize a drilling process and to recognize the finish of surfaces from the signals generated using a tactile sensor.

Grabec, I.; Grabec, D. (Univ. of Ljubljana, (Slovenia). Dept. of Physics); Sachse, W. (Cornell Univ., Ithaca, NY (United States). Dept. of Theoretical and Applied Sciences)

1993-10-01

98

ECEN 444-501: Digital Signal Processing, Fall `12 Review #2 Review (midterm exam #2)  

E-print Network

ECEN 444-501: Digital Signal Processing, Fall `12 Review #2 Review (midterm exam #2) z · Properties of z-transform. · Relationship between the z-transform and the Fourier transform of a signal x and correlation of signals in the time-domain. (Q: How to work this out in the z- domain?) · Given x[n] (or X

Yoon, Byung-Jun

99

Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures  

Microsoft Academic Search

Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some

Guang-Ming Zhang; David M. Harvey

2011-01-01

100

Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures  

Microsoft Academic Search

Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some

Guang-Ming Zhang; David M. Harvey

2012-01-01

101

Stepped-frequency radar signal processing  

NASA Astrophysics Data System (ADS)

Stepped-frequency radar is a prominent example of the class of continuous-wave radar systems. Since raw data are recorded in frequency-domain direct investigations referring to the frequency content can be done on the raw data. However, a transformation of these data is required in order to obtain a time-domain representation of the targets illuminated by the radar. In this paper we present different ways of arranging the raw data which then are processed by means of the inverse fast Fourier transform. On the basis of the time-domain result we discuss strengths and weaknesses of each of these data structures. Furthermore, we investigate the influence of phase noise on the time-domain signal by means of an appropriate model implemented in our simulation tool. We also demonstrate the effects of commonly known techniques of digital signal processing, such as windowing and zero-padding of frequency-domain data. Finally we present less commonly known methods, such as the processing gain of the (inverse) fast Fourier transform by means of which the signal to noise ratio of the time-domain signal can be increased.

Seyfried, Daniel; Schoebel, Joerg

2015-01-01

102

Ultrasonic correlator versus signal averager as a signal to noise enhancement instrument  

NASA Technical Reports Server (NTRS)

Ultrasonic inspection of thick and attenuating materials is hampered by the reduce amplitudes of the propagated waves to a degree that the noise is too high to enable meaningful interpretation of the data. In order to overcome the low signal to noise ratio (S/N), a correlation technique has been developed. In this method, a continuous pseudo-random pattern generated digitally is transmitted and detected by piezoelectric transducers. A correlation is performed in the instrument between the received signal and a variable delayed image of the transmitted one. The result is shown to be proportional to the impulse response of the investigated material, analogous to a signal received from a pulsed system, with an improved S/N ratio. The degree of S/N enhancement depends on the sweep rate. The correlator is described, and it is compared to the method of enhancing S/N ratio by averaging the signals. The similarities and differences between the two are highlighted and the potential advantage of the correlator system is explained.

Kishoni, Doron; Pietsch, Benjamin E.

1990-01-01

103

Time-dependent statistical and correlation properties of neural signals during handwriting.  

PubMed

To elucidate the cortical control of handwriting, we examined time-dependent statistical and correlational properties of simultaneously recorded 64-channel electroencephalograms (EEGs) and electromyograms (EMGs) of intrinsic hand muscles. We introduced a statistical method, which offered advantages compared to conventional coherence methods. In contrast to coherence methods, which operate in the frequency domain, our method enabled us to study the functional association between different neural regions in the time domain. In our experiments, subjects performed about 400 stereotypical trials during which they wrote a single character. These trials provided time-dependent EMG and EEG data capturing different handwriting epochs. The set of trials was treated as a statistical ensemble, and time-dependent correlation functions between neural signals were computed by averaging over that ensemble. We found that trial-to-trial variability of both the EMGs and EEGs was well described by a log-normal distribution with time-dependent parameters, which was clearly distinguished from the normal (Gaussian) distribution. We found strong and long-lasting EMG/EMG correlations, whereas EEG/EEG correlations, which were also quite strong, were short-lived with a characteristic correlation durations on the order of 100 ms or less. Our computations of correlation functions were restricted to the [Formula: see text] spectral range (13-30 Hz) of EEG signals where we found the strongest effects related to handwriting. Although, all subjects involved in our experiments were right-hand writers, we observed a clear symmetry between left and right motor areas: inter-channel correlations were strong if both channels were located over the left or right hemispheres, and 2-3 times weaker if the EEG channels were located over different hemispheres. Although we observed synchronized changes in the mean energies of EEG and EMG signals, we found that EEG/EMG correlations were much weaker than EEG/EEG and EMG/EMG correlations. The absence of strong correlations between EMG and EEG signals indicates that (i) a large fraction of the EEG signal includes electrical activity unrelated to low-level motor variability; (ii) neural processing of cortically-derived signals by spinal circuitry may reduce the correlation between EEG and EMG signals. PMID:22984455

Rupasov, Valery I; Lebedev, Mikhail A; Erlichman, Joseph S; Lee, Stephen L; Leiter, James C; Linderman, Michael

2012-01-01

104

Time-Dependent Statistical and Correlation Properties of Neural Signals during Handwriting  

PubMed Central

To elucidate the cortical control of handwriting, we examined time-dependent statistical and correlational properties of simultaneously recorded 64-channel electroencephalograms (EEGs) and electromyograms (EMGs) of intrinsic hand muscles. We introduced a statistical method, which offered advantages compared to conventional coherence methods. In contrast to coherence methods, which operate in the frequency domain, our method enabled us to study the functional association between different neural regions in the time domain. In our experiments, subjects performed about 400 stereotypical trials during which they wrote a single character. These trials provided time-dependent EMG and EEG data capturing different handwriting epochs. The set of trials was treated as a statistical ensemble, and time-dependent correlation functions between neural signals were computed by averaging over that ensemble. We found that trial-to-trial variability of both the EMGs and EEGs was well described by a log-normal distribution with time-dependent parameters, which was clearly distinguished from the normal (Gaussian) distribution. We found strong and long-lasting EMG/EMG correlations, whereas EEG/EEG correlations, which were also quite strong, were short-lived with a characteristic correlation durations on the order of 100 ms or less. Our computations of correlation functions were restricted to the spectral range (13–30 Hz) of EEG signals where we found the strongest effects related to handwriting. Although, all subjects involved in our experiments were right-hand writers, we observed a clear symmetry between left and right motor areas: inter-channel correlations were strong if both channels were located over the left or right hemispheres, and 2–3 times weaker if the EEG channels were located over different hemispheres. Although we observed synchronized changes in the mean energies of EEG and EMG signals, we found that EEG/EMG correlations were much weaker than EEG/EEG and EMG/EMG correlations. The absence of strong correlations between EMG and EEG signals indicates that (i) a large fraction of the EEG signal includes electrical activity unrelated to low-level motor variability; (ii) neural processing of cortically-derived signals by spinal circuitry may reduce the correlation between EEG and EMG signals. PMID:22984455

Rupasov, Valery I.; Lebedev, Mikhail A.; Erlichman, Joseph S.; Lee, Stephen L.; Leiter, James C.; Linderman, Michael

2012-01-01

105

Signal/noise enhancement strategies for stochastically estimated correlation functions  

E-print Network

We develop strategies for enhancing the signal/noise ratio for stochastically sampled correlation functions. The techniques are general and offer a wide range of applicability. We demonstrate the potential of the approach with a generic two-state system, and then explore the practical applicability of the method for single hadron correlators in lattice quantum chromodynamics. In the latter case, we determine the ground state energies of the pion, proton, and delta baryon, as well as the ground and first excited state energy of the rho meson using matrices of correlators computed on an exemplary ensemble of anisotropic gauge configurations. In the majority of cases, we find a modest reduction in the statistical uncertainties on extracted energies compared to conventional variational techniques. However, in the case of the delta baryon, we achieve a factor of three reduction in statistical uncertainties. The variety of outcomes achieved for single hadron correlators illustrates an inherent dependence of the method on the properties of the system under consideration and the operator basis from which the correlators are constructed.

William Detmold; Michael G. Endres

2014-04-27

106

Signal/noise enhancement strategies for stochastically estimated correlation functions  

NASA Astrophysics Data System (ADS)

We develop strategies for enhancing the signal/noise ratio for stochastically sampled correlation functions. The techniques are general and offer a wide range of applicability. We demonstrate the potential of the approach with a generic two-state system and then explore the practical applicability of the method for single hadron correlators in lattice quantum chromodynamics. In the latter case, we determine the ground state energies of the pion, proton, and delta baryon, as well as the ground and first excited state energy of the rho meson using matrices of correlators computed on an exemplary ensemble of anisotropic gauge configurations. In the majority of cases, we find a modest reduction in the statistical uncertainties on extracted energies compared to conventional variational techniques. However, in the case of the delta baryon, we achieve a factor of 3 reduction in statistical uncertainties. The variety of outcomes achieved for single hadron correlators illustrates an inherent dependence of the method on the properties of the system under consideration and the operator basis from which the correlators are constructed.

Detmold, William; Endres, Michael G.

2014-08-01

107

DIGITAL SIGNAL PROCESSING--FALL 2012 JAMES S. WALKER  

E-print Network

DIGITAL SIGNAL PROCESSING--FALL 2012 JAMES S. WALKER This course provides a comprehensive introduction to the use of Fourier methods in digital signal processing. Digital signal processing is a vast in sound signals. There is a follow-up course, Digital Image Processing (Math/Phys 440), which treats

Walker, James S.

108

Interpretation of AMS-02 results: correlations among dark matter signals  

SciTech Connect

The AMS-02 collaboration has recently released data on the positron fraction e{sup +}/(e{sup ?}+e{sup +}) up to energies of about 350 GeV. If one insists on interpreting the observed excess as a dark matter signal, then we find it is best described by a TeV-scale dark matter annihilating into ?{sup +}?{sup ?}, although this situation is already severely constrained by gamma-ray measurements.The annihilation into ?{sup +}?{sup ?} is allowed by gamma-rays more than ?{sup +}?{sup ?}, but it gives a poorer fit to AMS-02 data. Moreover, since electroweak corrections induce correlations among the fluxes of stable particles from dark matter annihilations, the recent AMS-02 data imply a well-defined prediction for the correlated flux of antiprotons. Under the assumption that their future measurements will not show any antiproton excess above the background, the dark matter interpretation of the positron rise will possibly be ruled out by only making use of data from a single experiment. This work is the first of a program where we emphasize the role of correlations among dark matter signals.

Simone, Andrea De [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Riotto, Antonio [Département de Physique Théorique and Centre for Astroparticle Physics (CAP), 24 quai E. Ansermet, CH-1211 Geneva (Switzerland); Xue, Wei, E-mail: andrea.desimone@sissa.it, E-mail: antonio.riotto@unige.ch, E-mail: wei.xue@sissa.it [SISSA, via Bonomea 265, I-34136 Trieste (Italy)

2013-05-01

109

Quantum Correlations as Correlations of Classical Gaussian Signals: "Entanglement" at the Subquantum Level  

NASA Astrophysics Data System (ADS)

We show that correlations between observables on composite quantum systems can be mathematically represented as correlations of quadratic forms of classical Gaussian signals. The formalism covers correlations for entangled quantum systems; for example, measurements of spin projections for two electrons in the singlet state. In this paper we show that at the subquantum level all quantum systems are correlated including systems in factorizable states. However, in the latter case quadratic forms of the prequantum fields (at the subquantum level these forms represent quantum observables) are uncorrelated. Thus "subquantum entanglement" for prequantum fields representing quantum systems in factorizable states cannot be found by using quantum observables. We have to go beyond quantum mechanics. Coupling with generalized quantum models of Mielnik and Zyczkowski are discussed.

Khrennikov, Andrei

2012-04-01

110

Ear Modeling and Sound Signal Processing Ear modeling can significantly improve sound signal processing and  

E-print Network

of digital sounds [5, 31]. It is routinely used for downloading and playing digital music. Scientifically into new tools of signal processing. Even though human auditory systems (or those of mammals such as cat

Xin, Jack

111

Overview of Digital Signal Processing (DSP) Chapter Intended Learning Outcomes  

E-print Network

Overview of Digital Signal Processing (DSP) Chapter Intended Learning Outcomes: (i) Understand digital signal processor sample at analog signal sampled signal t amplitude t amplitude 0 0 1 t amplitude and according to the two's complement representation. In digital signal processing (DSP), we deal

So, Hing-Cheung

112

FPGA-Based Filterbank Implementation for Parallel Digital Signal Processing  

NASA Technical Reports Server (NTRS)

One approach to parallel digital signal processing decomposes a high bandwidth signal into multiple lower bandwidth (rate) signals by an analysis bank. After processing, the subband signals are recombined into a fullband output signal by a synthesis bank. This paper describes an implementation of the analysis and synthesis banks using (Field Programmable Gate Arrays) FPGAs.

Berner, Stephan; DeLeon, Phillip

1999-01-01

113

Neural Networks for Signal Processing and Control  

NASA Astrophysics Data System (ADS)

Neural networks are developed for controlling a robot-arm and camera system and for processing images. The networks are based upon computational schemes that may be found in the brain. In the first network, a neural map algorithm is employed to control a five-joint pneumatic robot arm and gripper through feedback from two video cameras. The pneumatically driven robot arm employed shares essential mechanical characteristics with skeletal muscle systems. To control the position of the arm, 200 neurons formed a network representing the three-dimensional workspace embedded in a four-dimensional system of coordinates from the two cameras, and learned a set of pressures corresponding to the end effector positions, as well as a set of Jacobian matrices for interpolating between these positions. Because of the properties of the rubber-tube actuators of the arm, the position as a function of supplied pressure is nonlinear, nonseparable, and exhibits hysteresis. Nevertheless, through the neural network learning algorithm the position could be controlled to an accuracy of about one pixel (~3 mm) after two hundred learning steps. Applications of repeated corrections in each step via the Jacobian matrices leads to a very robust control algorithm since the Jacobians learned by the network have to satisfy the weak requirement that they yield a reduction of the distance between gripper and target. The second network is proposed as a model for the mammalian vision system in which backward connections from the primary visual cortex (V1) to the lateral geniculate nucleus play a key role. The application of hebbian learning to the forward and backward connections causes the formation of receptive fields which are sensitive to edges, bars, and spatial frequencies of preferred orientations. The receptive fields are learned in such a way as to maximize the rate of transfer of information from the LGN to V1. Orientational preferences are organized into a feature map in the primary visual cortex by the application of lateral interactions during the learning phase. The organization of the mature network is compared to that found in the macaque monkey by several analytical tests. The capacity of the network to process images is investigated. By a method of reconstructing the input images in terms of V1 activities, the simulations show that images can be faithfully represented in V1 by the proposed network. The signal-to-noise ratio of the image is improved by the representation, and compression ratios of well over two-hundred are possible. Lateral interactions between V1 neurons sharpen their orientational tuning. We further study the dynamics of the processing, showing that the rate of decrease of the error of the reconstruction is maximized for the receptive fields used. Lastly, we employ a Fokker-Planck equation for a more detailed prediction of the error value vs. time. The Fokker-Planck equation for an underdamped system with a driving force is derived, yielding an energy-dependent diffusion coefficient which is the integral of the spectral densities of the force and the velocity of the system. The theory is applied to correlated noise activation and resonant activation. Simulation results for the error of the network vs time are compared to the solution of the Fokker-Planck equation.

Hesselroth, Ted Daniel

114

Signal processing for ION mobility spectrometers  

NASA Technical Reports Server (NTRS)

Signal processing techniques for systems based upon Ion Mobility Spectrometry will be discussed in the light of 10 years of experience in the design of real-time IMS. Among the topics to be covered are compensation techniques for variations in the number density of the gas - the use of an internal standard (a reference peak) or pressure and temperature sensors. Sources of noise and methods for noise reduction will be discussed together with resolution limitations and the ability of deconvolution techniques to improve resolving power. The use of neural networks (either by themselves or as a component part of a processing system) will be reviewed.

Taylor, S.; Hinton, M.; Turner, R.

1995-01-01

115

Digital signal processor and processing method for GPS receivers  

NASA Technical Reports Server (NTRS)

A digital signal processor and processing method therefor for use in receivers of the NAVSTAR/GLOBAL POSITIONING SYSTEM (GPS) employs a digital carrier down-converter, digital code correlator and digital tracking processor. The digital carrier down-converter and code correlator consists of an all-digital, minimum bit implementation that utilizes digital chip and phase advancers, providing exceptional control and accuracy in feedback phase and in feedback delay. Roundoff and commensurability errors can be reduced to extremely small values (e.g., less than 100 nanochips and 100 nanocycles roundoff errors and 0.1 millichip and 1 millicycle commensurability errors). The digital tracking processor bases the fast feedback for phase and for group delay in the C/A, P.sub.1, and P.sub.2 channels on the L.sub.1 C/A carrier phase thereby maintaining lock at lower signal-to-noise ratios, reducing errors in feedback delays, reducing the frequency of cycle slips and in some cases obviating the need for quadrature processing in the P channels. Simple and reliable methods are employed for data bit synchronization, data bit removal and cycle counting. Improved precision in averaged output delay values is provided by carrier-aided data-compression techniques. The signal processor employs purely digital operations in the sense that exactly the same carrier phase and group delay measurements are obtained, to the last decimal place, every time the same sampled data (i.e., exactly the same bits) are processed.

Thomas, Jr., Jess B. (Inventor)

1989-01-01

116

Neural Processes of Preparatory Control for Stop Signal Inhibition  

PubMed Central

This study investigated the preparatory control of motor inhibition and motor execution using a stop signal task (SST) and functional magnetic resonance imaging (fMRI). In the SST, a frequent “go” signal triggered a prepotent response and a less frequent “stop” signal prompted the inhibition of this response. Preparatory control of motor inhibition and execution in the stop signal trials were examined by contrasting brain activation between stop success and stop error trials during the fore-period, in which participants prepared to respond to go or to stop. Results from 91 healthy adults showed greater activation in the right prefrontal cortex and inferior parietal lobule during preparatory motor inhibition. Preparatory motor execution activated bilateral putamen, primary motor cortices, posterior cingulate cortex, ventromedial prefrontal cortex, and superior temporal/intraparietal sulci. Furthermore, the extents of these inhibition and execution activities were inversely correlated across subjects. On the basis of a median split of the stop signal reaction time (SSRT), subjects with short SSRT showed greater activity in the right orbital frontal cortex during preparatory inhibition. These new findings suggest that the go and stop processes interact prior to target presentation in the SST, in accord with recent computational models of stop signal inhibition. PMID:21976392

Hu, Sien; Li, Chiang-Shan R.

2011-01-01

117

Radar transponder apparatus and signal processing technique  

DOEpatents

An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder's echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR.

Axline, Jr., Robert M. (Albuquerque, NM); Sloan, George R. (Albuquerque, NM); Spalding, Richard E. (Albuquerque, NM)

1996-01-01

118

Radar transponder apparatus and signal processing technique  

DOEpatents

An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder`s echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR. 4 figs.

Axline, R.M. Jr.; Sloan, G.R.; Spalding, R.E.

1996-01-23

119

Unique portable signal acquisition/processing station  

SciTech Connect

At Lawrence Livermore National Laboratory, there are experimental applications requiring digital signal acquisition as well as data reduction and analysis. A prototype Signal Acquisition/Processing Station (SAPS) has been constructed and is currently undergoing tests. The system employs an LSI-11/23 computer with Data Translation analog-to-digital hardware. SAPS is housed in a roll-around cart which has been designed to withstand most subtle EMI/RFI environments. A user-friendly menu allows a user to access powerful data acquisition packages with a minimum of training. The software architecture of SAPS involves two operating systems, each being transparent to the user. Since this is a general purpose workstation with several units being utilized, an emphasis on low cost, reliability, and maintenance was stressed during conception and design. The system is targeted for mid-range frequency data acquisition; between a data logger and a transient digitizer.

Garron, R.D.; Azevedo, S.G.

1983-05-16

120

Signal processing and tracking of arrivals in ocean acoustic tomography.  

PubMed

The signal processing for ocean acoustic tomography experiments has been improved to account for the scattering of the individual arrivals. The scattering reduces signal coherence over time, bandwidth, and space. In the typical experiment, scattering is caused by the random internal-wave field and results in pulse spreading (over arrival-time and arrival-angle) and wander. The estimator-correlator is an effective procedure that improves the signal-to-noise ratio of travel-time estimates and also provides an estimate of signal coherence. The estimator-correlator smoothes the arrival pulse at the expense of resolution. After an arrival pulse has been measured, it must be associated with a model arrival, typically a ray arrival. For experiments with thousands of transmissions, this is a tedious task that is error-prone when done manually. An error metric that accounts for peak amplitude as well as travel-time and arrival-angle can be defined. The Viterbi algorithm can then be adapted to the task of automated peak tracking. Repeatable, consistent results are produced that are superior to a manual tracking procedure. The tracking can be adjusted by tuning the error metric in logical, quantifiable manner. PMID:25373953

Dzieciuch, Matthew A

2014-11-01

121

Hybrid integrated optic modules for real-time signal processing  

NASA Technical Reports Server (NTRS)

The most recent progress on four relatively new hybrid integrated optic device modules in LiNbO3 waveguides and one in YIG/GGG waveguide that are currently being studied are discussed. The five hybrid modules include a time-integrating acoustooptic correlator, a channel waveguide acoustooptic frequency shifter/modulator, an electrooptic channel waveguide total internal reflection moculator/switch, an electrooptic analog-to-digital converter using a Fabry-Perot modulator array, and a noncollinear magnetooptic modulator using magnetostatic surface waves. All of these devices possess the desirable characteristics of very large bandwidth (GHz or higher), very small substrate size along the optical path (typically 1.5 cm or less), single-mode optical propagation, and low drive power requirement. The devices utilize either acoustooptic, electrooptic or magnetooptic effects in planar or channel waveguides and, therefore, act as efficient interface devices between a light wave and temporal signals. Major areas of application lie in wideband multichannel optical real-time signal processing and communications. Some of the specific applications include spectral analysis and correlation of radio frequency (RF) signals, fiber-optic sensing, optical computing and multiport switching/routing, and analog-to-digital conversion of wide RF signals.

Tsai, C. S.

1984-01-01

122

Molecular signaling network complexity is correlated with cancer patient survivability  

PubMed Central

The 5-y survival for cancer patients after diagnosis and treatment is strongly dependent on tumor type. Prostate cancer patients have a >99% chance of survival past 5 y after diagnosis, and pancreatic patients have <6% chance of survival past 5 y. Because each cancer type has its own molecular signaling network, we asked if there are “signatures” embedded in these networks that inform us as to the 5-y survival. In other words, are there statistical metrics of the network that correlate with survival? Furthermore, if there are, can such signatures provide clues to selecting new therapeutic targets? From the Kyoto Encyclopedia of Genes and Genomes Cancer Pathway database we computed several conventional and some less conventional network statistics. In particular we found a correlation (R2 = 0.7) between degree-entropy and 5-y survival based on the Surveillance Epidemiology and End Results database. This correlation suggests that cancers that have a more complex molecular pathway are more refractory than those with less complex molecular pathway. We also found potential new molecular targets for drugs by computing the betweenness—a statistical metric of the centrality of a node—for the molecular networks. PMID:22615392

Breitkreutz, Dylan; Hlatky, Lynn; Rietman, Edward; Tuszynski, Jack A.

2012-01-01

123

Molecular signaling network complexity is correlated with cancer patient survivability.  

PubMed

The 5-y survival for cancer patients after diagnosis and treatment is strongly dependent on tumor type. Prostate cancer patients have a >99% chance of survival past 5 y after diagnosis, and pancreatic patients have <6% chance of survival past 5 y. Because each cancer type has its own molecular signaling network, we asked if there are "signatures" embedded in these networks that inform us as to the 5-y survival. In other words, are there statistical metrics of the network that correlate with survival? Furthermore, if there are, can such signatures provide clues to selecting new therapeutic targets? From the Kyoto Encyclopedia of Genes and Genomes Cancer Pathway database we computed several conventional and some less conventional network statistics. In particular we found a correlation (R(2) = 0.7) between degree-entropy and 5-y survival based on the Surveillance Epidemiology and End Results database. This correlation suggests that cancers that have a more complex molecular pathway are more refractory than those with less complex molecular pathway. We also found potential new molecular targets for drugs by computing the betweenness--a statistical metric of the centrality of a node--for the molecular networks. PMID:22615392

Breitkreutz, Dylan; Hlatky, Lynn; Rietman, Edward; Tuszynski, Jack A

2012-06-01

124

Neural correlates of processing passive sentences.  

PubMed

Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., object-relative clauses) elicits activation in the left inferior frontal gyrus (IFG) and left posterior temporal cortex. However, relatively little is known about the neural correlates of processing passive sentences, which differ from other complex sentences in terms of representation (i.e., noun phrase (NP)-movement) and processing (i.e., the time course of syntactic reanalysis). In the present study, 27 adults (14 younger and 13 older) listened to passive and active sentences and performed a sentence-picture verification task using functional Magnetic Resonance Imaging (fMRI). Passive sentences, relative to active sentences, elicited greater activation in bilateral IFG and left temporo-occipital regions. Participant age did not significantly affect patterns of activation. Consistent with previous research, activation in left temporo-occipital cortex likely reflects thematic reanalysis processes, whereas, activation in the left IFG supports processing of complex syntax (i.e., NP-movement). Right IFG activation may reflect syntactic reanalysis processing demands associated with the sentence-picture verification task. PMID:24961525

Mack, Jennifer E; Meltzer-Asscher, Aya; Barbieri, Elena; Thompson, Cynthia K

2013-01-01

125

Neural Correlates of Processing Passive Sentences  

PubMed Central

Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., object-relative clauses) elicits activation in the left inferior frontal gyrus (IFG) and left posterior temporal cortex. However, relatively little is known about the neural correlates of processing passive sentences, which differ from other complex sentences in terms of representation (i.e., noun phrase (NP)-movement) and processing (i.e., the time course of syntactic reanalysis). In the present study, 27 adults (14 younger and 13 older) listened to passive and active sentences and performed a sentence-picture verification task using functional Magnetic Resonance Imaging (fMRI). Passive sentences, relative to active sentences, elicited greater activation in bilateral IFG and left temporo-occipital regions. Participant age did not significantly affect patterns of activation. Consistent with previous research, activation in left temporo-occipital cortex likely reflects thematic reanalysis processes, whereas, activation in the left IFG supports processing of complex syntax (i.e., NP-movement). Right IFG activation may reflect syntactic reanalysis processing demands associated with the sentence-picture verification task. PMID:24961525

Mack, Jennifer E.; Meltzer-Asscher, Aya; Barbieri, Elena; Thompson, Cynthia K.

2013-01-01

126

Efficient audio signal processing for embedded systems  

NASA Astrophysics Data System (ADS)

As mobile platforms continue to pack on more computational power, electronics manufacturers start to differentiate their products by enhancing the audio features. However, consumers also demand smaller devices that could operate for longer time, hence imposing design constraints. In this research, we investigate two design strategies that would allow us to efficiently process audio signals on embedded systems such as mobile phones and portable electronics. In the first strategy, we exploit properties of the human auditory system to process audio signals. We designed a sound enhancement algorithm to make piezoelectric loudspeakers sound ”richer" and "fuller." Piezoelectric speakers have a small form factor but exhibit poor response in the low-frequency region. In the algorithm, we combine psychoacoustic bass extension and dynamic range compression to improve the perceived bass coming out from the tiny speakers. We also developed an audio energy reduction algorithm for loudspeaker power management. The perceptually transparent algorithm extends the battery life of mobile devices and prevents thermal damage in speakers. This method is similar to audio compression algorithms, which encode audio signals in such a ways that the compression artifacts are not easily perceivable. Instead of reducing the storage space, however, we suppress the audio contents that are below the hearing threshold, therefore reducing the signal energy. In the second strategy, we use low-power analog circuits to process the signal before digitizing it. We designed an analog front-end for sound detection and implemented it on a field programmable analog array (FPAA). The system is an example of an analog-to-information converter. The sound classifier front-end can be used in a wide range of applications because programmable floating-gate transistors are employed to store classifier weights. Moreover, we incorporated a feature selection algorithm to simplify the analog front-end. A machine learning algorithm AdaBoost is used to select the most relevant features for a particular sound detection application. In this classifier architecture, we combine simple "base" analog classifiers to form a strong one. We also designed the circuits to implement the AdaBoost-based analog classifier.

Chiu, Leung Kin

127

A Signal Processing Model of Quantum Mechanics  

E-print Network

This paper develops a deterministic model of quantum mechanics as an accumulation-and-threshold process. The model arises from an analogy with signal processing in wireless communications. Complex wavefunctions are interpreted as expressing the amplitude and phase information of a modulated carrier wave. Particle transmission events are modeled as the outcome of a process of signal accumulation that occurs in an extra (non-spacetime) dimension. Besides giving a natural interpretation of the wavefunction and the Born rule, the model accommodates the collapse of the wave packet and other quantum paradoxes such as EPR and the Ahanorov-Bohm effect. The model also gives a new perspective on the 'relational' nature of quantum mechanics: that is, whether the wave function of a physical system is "real" or simply reflects the observer's partial knowledge of the system. We simulate the model for a 2-slit experiment, and indicate possible deviations of the model's predictions from conventional quantum mechanics. We also indicate how the theory may be extended to a field theory.

Chris Thron; Johnny Watts

2012-05-08

128

Cellular defense processes regulated by pathogen-elicited receptor signaling  

NASA Astrophysics Data System (ADS)

Vertebrates are constantly threatened by the invasion of microorganisms and have evolved systems of immunity to eliminate infectious pathogens in the body. Initial sensing of microbial agents is mediated by the recognition of pathogens by means of molecular structures expressed uniquely by microbes of a given type. So-called 'Toll-like receptors' are expressed on host epithelial barrier cells play an essential role in the host defense against microbial pathogens by inducing cell responses (e.g., proliferation, death, cytokine secretion) via activation of intracellular signaling networks. As these networks, comprising multiple interconnecting dynamic pathways, represent highly complex multi-variate "information processing" systems, the signaling activities particularly critical for governing the host cell responses are poorly understood and not easily ascertained by a priori theoretical notions. We have developed over the past half-decade a "data-driven" computational modeling approach, on a 'cue-signal-response' combined experiment/computation paradigm, to elucidate key multi-variate signaling relationships governing the cell responses. In an example presented here, we study how a canonical set of six kinase pathways combine to effect microbial agent-induced apoptotic death of a macrophage cell line. One modeling technique, partial least-squares regression, yielded the following key insights: {a} signal combinations most strongly correlated to apoptotic death are orthogonal to those most strongly correlated with release of inflammatory cytokines; {b} the ratio of two key pathway activities is the most powerful predictor of microbe-induced macrophage apoptotic death; {c} the most influential time-window of this signaling activity ratio is surprisingly fast: less than one hour after microbe stimulation.

Wu, Rongcong; Goldsipe, Arthur; Schauer, David B.; Lauffenburger, Douglas A.

2011-06-01

129

Digital signal processing methods for biosequence comparison.  

PubMed Central

A method is discussed for DNA or protein sequence comparison using a finite field fast Fourier transform, a digital signal processing technique; and statistical methods are discussed for analyzing the output of this algorithm. This method compares two sequences of length N in computing time proportional to N log N compared to N2 for methods currently used. This method makes it feasible to compare very long sequences. An example is given to show that the method correctly identifies sites of known homology. PMID:2349096

Benson, D C

1990-01-01

130

Digital signal processing for radioactive decay studies  

SciTech Connect

The use of digital acquisition system has been instrumental in the investigation of proton and alpha emitting nuclei. Recent developments extend the sensitivity and breadth of the application. The digital signal processing capabilities, used predominately by UT/ORNL for decay studies, include digitizers with decreased dead time, increased sampling rates, and new innovative firmware. Digital techniques and these improvements are furthermore applicable to a range of detector systems. Improvements in experimental sensitivity for alpha and beta-delayed neutron emitters measurements as well as the next generation of superheavy experiments are discussed.

Miller, D.; Madurga, M.; Paulauskas, S. V. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Ackermann, D.; Heinz, S.; Hessberger, F. P.; Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64220, Darmstadt (Germany); Grzywacz, R. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Miernik, K.; Rykaczewski, K. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Tan, H. [XIA LLC, Hayward, CA 94544 (United States)

2011-11-30

131

An Introduction to Signal Processing in Chemical Analysis  

NSDL National Science Digital Library

This 26-page illustrated introduction to digital signal processing in chemical analysis covers signal arithmetic, signals and noise, smoothing, differentiation, resolution enhancement, harmonic analysis, convolution, deconvolution, Fourier filter, integration and peak area measurement, and curve fitting. It is accompanied by signal processing software for Macintosh with reference manual and tutorial (available for free download), video demonstrations, and Matlab signal processing modules for Mac, PC, and Unix.

O'Haver, Professor T.

132

GLAST Burst Monitor Signal Processing System  

SciTech Connect

The onboard Data Processing Unit (DPU), designed and built by Southwest Research Institute, performs the high-speed data acquisition for GBM. The analog signals from each of the 14 detectors are digitized by high-speed multichannel analog data acquisition architecture. The streaming digital values resulting from a periodic (period of 104.2 ns) sampling of the analog signal by the individual ADCs are fed to a Field-Programmable Gate Array (FPGA). Real-time Digital Signal Processing (DSP) algorithms within the FPGA implement functions like filtering, thresholding, time delay and pulse height measurement. The spectral data with a 12-bit resolution are formatted according to the commandable look-up-table (LUT) and then sent to the High-Speed Science-Date Bus (HSSDB, speed=1.5 MB/s) to be telemetered to ground. The DSP offers a novel feature of a commandable and constant event deadtime. The ADC non-linearities have been calibrated so that the spectral data can be corrected during analysis. The best temporal resolution is 2 {mu}s for the pre-burst and post-trigger time-tagged events (TTE) data. The time resolution of the binned data types is commandable from 64 msec to 1.024 s for the CTIME data (8 channel spectral resolution) and 1.024 to 32.768 s for the CSPEC data (128 channel spectral resolution). The pulse pile-up effects have been studied by Monte Carlo simulations. For a typical GRB, the possible shift in the Epeak value at high-count rates ({approx}100 kHz) is {approx}1% while the change in the single power-law index could be up to 5%.

Bhat, P. Narayana; Briggs, Michael; Connaughton, Valerie; Paciesas, William; Preece, Robert [University of Alabama, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Diehl, Roland; Greiner, Jochen; Kienlin, Andreas von; Lichti, Giselher; Steinle, Helmut [Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 85748, Garching (Germany); Fishman, Gerald; Kouveliotou, Chryssa; Meegan, Charles; Wilson-Hodge, Colleen [Marshall Space Flight Center, VP62, Huntsville, AL 35812 (United States); Kippen, R. Marc [Los Alamos National Laboratory, ISR-1, MS B244, Los Alamos, NM 87545 (United States); Persyn, Steven [Southwest Research Institute, Dept. of Space Systems, 6220 Culebra Road, San Antonio, TX 78238 (United States)

2007-07-12

133

Correlation of GPS signal fades due to ionospheric scintillation for aviation applications  

NASA Astrophysics Data System (ADS)

Deep and frequent Global Positioning System (GPS) signal fading due to strong ionospheric scintillation is a major concern for GPS-guided aviation in equatorial areas during high solar activity. A GPS aviation receiver may lose carrier tracking lock under deep fading, and a lost channel cannot be used for position calculation until lock is reestablished. Hence, frequent loss of lock due to frequent fading can significantly reduce the availability of GPS aviation. However, the geometric diversity of the satellites can mitigate scintillation impact on GPS aviation depending on the correlation level of deep fades between satellites. This paper proposes a metric to measure the correlation level of two fading channels from the perspective of GPS aviation. Using this metric, the satellite-to-satellite correlation is studied based on real scintillation data. The low satellite-to-satellite correlation shown in this paper envisions notable availability benefit from the geometric diversity of satellites under strong scintillation. In addition, this paper proposes a way to generate correlated fading processes with arbitrary correlation coefficients. Using this correlated fading process model, the availability of Localizer Performance with Vertical guidance (LPV)-200 under severe scintillation scenarios is analyzed. The result emphasizes the importance of a fast reacquisition capability of an aviation receiver after a brief outage, which is not currently mandated by the aviation receiver performance standards.

Seo, Jiwon; Walter, Todd; Enge, Per

2011-05-01

134

Signal processing techniques for damage detection with piezoelectric wafer active sensors and embedded ultrasonic structural radar  

NASA Astrophysics Data System (ADS)

Embedded ultrasonic structural radar (EUSR) algorithm is developed for using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. Signal processing techniques are used to extract the time of flight of the wave packages, and thereby to determine the location of the defects with the EUSR algorithm. In our research, the transient tone-burst wave propagation signals are generated and collected by the embedded PWAS. Then, with signal processing, the frequency contents of the signals and the time of flight of individual frequencies are determined. This paper starts with an introduction of embedded ultrasonic structural radar algorithm. Then we will describe the signal processing methods used to extract the time of flight of the wave packages. The signal processing methods being used include the wavelet denoising, the cross correlation, and Hilbert transform. Though hardware device can provide averaging function to eliminate the noise coming from the signal collection process, wavelet denoising is included to ensure better signal quality for the application in real severe environment. For better recognition of time of flight, cross correlation method is used. Hilbert transform is applied to the signals after cross correlation in order to extract the envelope of the signals. Signal processing and EUSR are both implemented by developing a graphical user-friendly interface program in LabView. We conclude with a description of our vision for applying EUSR signal analysis to structural health monitoring and embedded nondestructive evaluation. To this end, we envisage an automatic damage detection application utilizing embedded PWAS, EUSR, and advanced signal processing.

Yu, Lingyu; Bao, Jingjing; Giurgiutiu, Victor

2004-07-01

135

Advances in white-light optical signal processing  

NASA Technical Reports Server (NTRS)

A technique that permits signal processing operations which can be carried out by white light source is described. The method performs signal processing that obeys the concept of coherent light rather than incoherent optics. Since the white light source contains all the color wavelengths of the visible light, the technique is very suitable for color signal processing.

Yu, F. T. S.

1984-01-01

136

DIGITAL SIGNAL PROCESSING AS A DIAGNOSTIC TOOL FOR GAS  

E-print Network

DIGITAL SIGNAL PROCESSING AS A DIAGNOSTIC TOOL FOR GAS TUNGSTEN ARC WELDING Carl D. Sorensen is the welding arc itself. The sensory information is obtained through digital signal processing of the arc vol- tage and current. Experiments performed to test the suitability of digital signal processing as an arc

Eagar, Thomas W.

137

Signal processing issues in reflection tomography  

NASA Astrophysics Data System (ADS)

This dissertation focuses on signal modeling and processing issues of the following problems in reflection tomography: synthetic aperture radar (SAR) imaging of a runway and surroundings from an aircraft approaching for landing, acoustic imaging of objects buried in soil, and lidar imaging of underwater objects. The highly squinted geometry of runway imaging necessitates the incorporation of wavefront curvature into the signal model. We investigate the feasibility of using the wavenumber-domain (? - k) SAR inversion algorithm, which models the actual curvature of the wavefront, for runway imaging. We demonstrate the aberrations that the algorithm can produce when the squint angle is close to 90° and show that high-quality reconstruction is still possible provided that the interpolation is performed accurately enough, which can be achieved by increasing the temporal sampling rate. We compare the performance with that of a more general inversion method (GIM) that solves the measurement equation directly. The performances of both methods are comparable in the noise- free case. Being inherently robust to noise, GIM produces superior results in the noisy case. We also present a solution to the left-right ambiguity of runway imaging using interferometric processing. In imaging of objects buried in soil, we pursue an acoustic approach primarily for detection and imaging of cultural artifacts. We have developed a mathematical model and associated computer software in order to simulate the signals acquired by the actual experimental system, and a bistatic SAR-type algorithm for reconstruction. In the reconstructions from simulated data, objects were detectable, but near-field objects suffered from shifts and smears. To account for wavefront curvature, we formulated processing of the simulated data using the 3-D version of the monostatic ? - k algorithm. In lidar imaging of underwater objects, we formulate the problem as a 3-D tomographic reconstruction problem. We have developed software to simulate lidar returns at airborne receivers using the bistatic lidar return equations. Our simulator can model multiple scattering and absorption for various water types and system parameters. Our simulated data fits the characteristics of real data very well. We present our reconstruction results from the simulated and real data, and comparatively discuss the reconstructions.

Cadalli, Nail

2001-12-01

138

A Novel Approach for Adaptive Signal Processing  

NASA Technical Reports Server (NTRS)

Adaptive linear predictors have been used extensively in practice in a wide variety of forms. In the main, their theoretical development is based upon the assumption of stationarity of the signals involved, particularly with respect to the second order statistics. On this basis, the well-known normal equations can be formulated. If high- order statistical stationarity is assumed, then the equivalent normal equations involve high-order signal moments. In either case, the cross moments (second or higher) are needed. This renders the adaptive prediction procedure non-blind. A novel procedure for blind adaptive prediction has been proposed and considerable implementation has been made in our contributions in the past year. The approach is based upon a suitable interpretation of blind equalization methods that satisfy the constant modulus property and offers significant deviations from the standard prediction methods. These blind adaptive algorithms are derived by formulating Lagrange equivalents from mechanisms of constrained optimization. In this report, other new update algorithms are derived from the fundamental concepts of advanced system identification to carry out the proposed blind adaptive prediction. The results of the work can be extended to a number of control-related problems, such as disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. The applications implemented are speech processing, such as coding and synthesis. Simulations are included to verify the novel modelling method.

Chen, Ya-Chin; Juang, Jer-Nan

1998-01-01

139

Monte Carlo methods for signal processing: a review in the statistical signal processing context  

Microsoft Academic Search

In this article, MCMC (Markov chain Monte Carlo methods) and SMC (sequential Monte Carlo methods) are introduced to sample and\\/or maximize high-dimensional probability distributions. These methods enable to perform likelihood or Bayesian inference for complex non-Gaussian signal processing problems.

A. Doucet; Xiaodong Wang

2005-01-01

140

Signal processing of aircraft flyover noise  

NASA Technical Reports Server (NTRS)

A detailed analysis of signal processing concerns for measuring aircraft flyover noise is presented. Development of a de-Dopplerization scheme for both corrected time history and spectral data is discussed along with an analysis of motion effects on measured spectra. A computer code was written to implement the de-Dopplerization scheme. Input to the code is the aircraft position data and the pressure time histories. To facilitate ensemble averaging, a uniform level flyover is considered but the code can accept more general flight profiles. The effects of spectral smearing and its removal is discussed. Using data acquired from XV-15 tilt rotor flyover test comparisons are made showing the measured and corrected spectra. Frequency shifts are accurately accounted for by the method. It is shown that correcting for spherical spreading, Doppler amplitude, and frequency can give some idea about source directivity. The analysis indicated that smearing increases with frequency and is more severe on approach than recession.

Kelly, Jeffrey J.

1991-01-01

141

FPGA Signal Processing for Real-Time Dust Detection  

NASA Astrophysics Data System (ADS)

The NASA Lunar Science Institute's Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) has completed the construction of a 3MV lunar dust accelerator facility to investigate the effects of micrometeoroid impacts on the surface of the Moon. Such impacts are believed to contribute to the lunar exosphere, and might be primarily responsible for the mixing and redistribution of the lunar soil. Beyond physical understanding of lunar and other airless bodies, the accelerator will also offer experimental services for the calibration of future instruments. This system consists of calibrated image-charge detectors sensitive from 1.0E4 - 4.0E6 electrons per particle. A cross-correlation algorithm, implemented on a field programmable gate array (FPGA), is used to detect signals lost within noise. The parallelism and easy implementation of FPGA algorithms offer a good solution for real-time, fast filtration schemes. The implementation of this system, as well as the usefulness of FPGAs to the broader context of digital filtration, is presented. The technique is of general interest for any signal processing problems in a low signal-to-noise environment where the signals are of a known shape and can be easily realizable using National Instruments' LabVIEW development tools.

Thomas, E.; Auer, S.; Collette, A.; Drake, K.; Horanyi, M.; Munsat, T.; Shu, A. J.; Sternovsky, Z.

2011-12-01

142

Correlation analysis of electromyogram signals for multiuser myoelectric interfaces.  

PubMed

An inability to adapt myoelectric interfaces to a novel user's unique style of hand motion, or even to adapt to the motion style of an opposite limb upon which the interface is trained, are important factors inhibiting the practical application of myoelectric interfaces. This is mainly attributed to the individual differences in the exhibited electromyogram (EMG) signals generated by the muscles of different limbs. We propose in this paper a multiuser myoelectric interface which easily adapts to novel users and maintains good movement recognition performance. The main contribution is a framework for implementing style-independent feature transformation by using canonical correlation analysis (CCA) in which different users' data is projected onto a unified-style space. The proposed idea is summarized into three steps: 1) train a myoelectric pattern classifier on the set of style-independent features extracted from multiple users using the proposed CCA-based mapping; 2) create a new set of features describing the movements of a novel user during a quick calibration session; and 3) project the novel user's features onto a lower dimensional unified-style space with features maximally correlated with training data and classify accordingly. The proposed method has been validated on a set of eight intact-limbed subjects, left-and-right handed, performing ten classes of bilateral synchronous fingers movements with four electrodes on each forearm. The method was able to overcome individual differences through the style-independent framework with accuracies of > 83% across multiple users. Testing was also performed on a set of ten intact-limbed and six below-elbow amputee subjects as they performed finger and thumb movements. The proposed framework allowed us to train the classifier on a normal subject's data while subsequently testing it on an amputee's data after calibration with a performance of > 82% on average across all amputees. PMID:24760933

Khushaba, Rami N

2014-07-01

143

International Scholarly Research Network ISRN Signal Processing  

E-print Network

the original work is properly cited. We propose a new method called spectral intrinsic decomposition (SID The signal decomposition into atoms is an popular approach in signal analysis. The Fourier representation of signals have like pursuit methods [3], the Poper Orthogonal Decomposition (POD) [4], or Singular Value

Boyer, Edmond

144

Space-time signal processing for wireless communications: a survey  

Microsoft Academic Search

This survey paper reviews space-time signal processing (STP) in mobile wireless communications. Space-time processing refers to manipulating signals that are received at or transmitted from an antenna array so as to improve performance. We focus on antenna arrays deployed at the base stations since such applications are of current practical interest. We first introduce channel and signal models for base

Constantinos B. Papadias; Arogyaswami J. Paulraj

1997-01-01

145

Optimization of signal processing software for control system implementation  

Microsoft Academic Search

Signal processing plays a fundamental role in the design of control systems — the portion of a digitally-implemented control system between the sensor outputs and the actuator inputs is precisely a digital signal processor (DSP). Consequently, effective techniques for design and optimization of signal processing software are important in achieving efficient controller implementations. Motivated by these relationships, this paper reviews

Shuvra S. Bhattacharyya; William S. Levine

2006-01-01

146

Pedagogical reforms of digital signal processing education  

NASA Astrophysics Data System (ADS)

The future of the engineering discipline is arguably predicated heavily upon appealing to the future generation, in all its sensibilities. The greatest burden in doing so, one might rightly believe, lies on the shoulders of the educators. In examining the causal means by which the profession arrived at such a state, one finds that the technical revolution, precipitated by global war, had, as its catalyst, institutions as expansive as the government itself to satisfy the demand for engineers, who, as a result of such an existential crisis, were taught predominantly theoretical underpinnings to address a finite purpose. By contrast, the modern engineer, having expanded upon this vision and adapted to an evolving society, is increasingly placed in the proverbial role of the worker who must don many hats: not solely a scientist, yet often an artist; not a businessperson alone, but neither financially naive; not always a representative, though frequently a collaborator. Inasmuch as change then serves as the only constancy in a global climate, therefore, the educational system - if it is to mimic the demands of the industry - is left with an inherent need for perpetual revitalization to remain relevant. This work aims to serve that end. Motivated by existing research in engineering education, an epistemological challenge is molded into the framework of the electrical engineer with emphasis on digital signal processing. In particular, it is investigated whether students are better served by a learning paradigm that tolerates and, when feasible, encourages error via a medium free of traditional adjudication. Through the creation of learning modules using the Adobe Captivate environment, a wide range of fundamental knowledge in signal processing is challenged within the confines of existing undergraduate courses. It is found that such an approach not only conforms to the research agenda outlined for the engineering educator, but also reflects an often neglected reality: that the student who is free to be creative, free to err, and free to self-correct is emblematic of the profession -- past, present, and future -- to which he or she unwittingly aspires.

Christensen, Michael

147

Advanced Turbulence Measurements and Signal Processing for Hydropower Flow Characterization  

E-print Network

accelerated recovery of the near wake flow due to increased turbulent mixing. · Error QuantificationAdvanced Turbulence Measurements and Signal Processing for Hydropower Flow Characterization The turbulence measurements group has extensive experience and expertise in turbulent flow measurements, signal

148

Optimal signal processing for continuous qubit readout  

E-print Network

The measurement of a quantum two-level system, or a qubit in modern terminology, often involves an electromagnetic field that interacts with the qubit, before the field is measured continuously and the qubit state is inferred from the noisy field measurement. During the measurement, the qubit may undergo spontaneous transitions, further obscuring the initial qubit state from the observer. Taking advantage of some well known techniques in stochastic detection theory, here we propose a novel signal processing protocol that can infer the initial qubit state optimally from the measurement in the presence of noise and qubit dynamics. Assuming continuous quantum-nondemolition measurements with Gaussian or Poissonian noise and a classical Markov model for the qubit, we derive analytic solutions to the protocol in some special cases of interest using It\\={o} calculus. Our method is applicable to multi-hypothesis testing for robust qubit readout and relevant to experiments on qubits in superconducting microwave circuits, trapped ions, nitrogen-vacancy centers in diamond, semiconductor quantum dots, or phosphorus donors in silicon.

Shilin Ng; Mankei Tsang

2014-08-06

149

Integrated optical signal processing with magnetostatic waves  

NASA Technical Reports Server (NTRS)

Magneto-optical devices based on Bragg diffraction of light by magnetostatic waves (MSW's) offer the potential of large time-bandwidth optical signal processing at microwave frequencies of 1 to 20 GHz and higher. A thin-film integrated-optical configuration, with the interacting MSW and guided-optical wave both propagating in a common ferrite layer, is necessary to avoid shape-factor demagnetization effects. The underlying theory of the MSW-optical interaction is outlined, including the development of expressions for optical diffraction efficiency as a function of MSW power and other relevant parameters. Bradd diffraction of guided-optical waves by transversely-propagating magnetostatic waves and collinear TE/TM mode conversion included by MSW's have been demonstrated in yttrium iron garnet (YIG) thin films. Diffraction levels as large as 4% (7 mm interaction length) and a modulation dynamic range of approx 30 dB have been observed. Advantages of these MSW-based devices over the analogous acousto-optical devices include: much greater operating frequencies, tunability of the MSW dispersion relation by varying either the RF frequency or the applied bias magnetic field, simple broad-band MSW transducer structures (e.g., a single stripline), and the potential for very high diffraction efficiencies.

Fisher, A. D.; Lee, J. N.

1984-01-01

150

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING Int. J. Adapt. Control Signal Process. 2012; 26:690691  

E-print Network

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING Int. J. Adapt. Control Signal control' Dedicated to Edoardo Mosca for his 70th birthday This issue of the International Journal of Adaptive Control and Signal Processing contains invited papers dedicated to Edoardo Mosca on the occasion

Hespanha, João Pedro

151

A block-parallel signal processing system for CMOS image sensor with three-dimensional structure  

Microsoft Academic Search

In this paper, we describe the fundamental study of the block-parallel analog signal processing elements which includes CMOS image sensor, correlated double sampling (CDS) array, and analog-to-digital converter (ADC) array. To realize high-speed image capturing sensor, we have proposed a blockparallel signal processing with three-dimensional (3-D) structure. In proposed system, one block consists of 3 stacked layers which are 100

K. Kiyoyama; K-W Lee; T. Fukushima; H. Naganuma; H. Kobayashi; T. Tanaka; M. Koyanagi

2010-01-01

152

Processing Motion Signals in Complex Environments  

NASA Technical Reports Server (NTRS)

Motion information is critical for human locomotion and scene segmentation. Currently we have excellent neurophysiological models that are able to predict human detection and discrimination of local signals. Local motion signals are insufficient by themselves to guide human locomotion and to provide information about depth, object boundaries and surface structure. My research is aimed at understanding the mechanisms underlying the combination of motion signals across space and time. A target moving on an extended trajectory amidst noise dots in Brownian motion is much more detectable than the sum of signals generated by independent motion energy units responding to the trajectory segments. This result suggests that facilitation occurs between motion units tuned to similar directions, lying along the trajectory path. We investigated whether the interaction between local motion units along the motion direction is mediated by contrast. One possibility is that contrast-driven signals from motion units early in the trajectory sequence are added to signals in subsequent units. If this were the case, then units later in the sequence would have a larger signal than those earlier in the sequence. To test this possibility, we compared contrast discrimination thresholds for the first and third patches of a triplet of sequentially presented Gabor patches, aligned along the motion direction. According to this simple additive model, contrast increment thresholds for the third patch should be higher than thresholds for the first patch.The lack of a measurable effect on contrast thresholds for these various manipulations suggests that the pooling of signals along a trajectory is not mediated by contrast-driven signals. Instead, these results are consistent with models that propose that the facilitation of trajectory signals is achieved by a second-level network that chooses the strongest local motion signals and combines them if they occur in a spatio-temporal sequence consistent with a trajectory. These results parallel the lack of increased apparent contrast along a static contour made up of similarly oriented elements.

Verghese, Preeti

2000-01-01

153

Accelerating biomedical signal processing algorithms with parallel programming on graphic processor units  

Microsoft Academic Search

This paper investigates the benefits derived by adopting the use of Graphics Processing Unit (GPU) parallel programming in the field of biomedical signal processing. The differences in execution time when computing the Correlation Dimension (CD) of multivariate neurophysiological recordings and the Skin Conductance Level (SCL) are reported by comparing several common programming environments. Moreover, as indicated in this study, the

Evdokimos I. Konstantinidis; Christos A. Frantzidis; Lazaros Tzimkas; Costas Pappas; P. D. Bamidis

2009-01-01

154

Statistical signal processing in sensor networks  

NASA Astrophysics Data System (ADS)

In this dissertation we focus on decentralized signal processing in Sensor Networks (SN). Four topics are studied: (i) Direction of Arrival (DOA) estimation using a Wireless Sensor network (WSN), (ii) multiple target tracking in large SN, (iii) decentralized target detection in SN and (iv) decentralized sequential detection in SN with communication constraints. The first topic of this thesis addresses the problem of estimating the DOA of an acoustic wavefront using a a WSN made of isotropic (hence individually useless) sensors. The WSN was designed according to the SENMA (SEnsor Network with Mobile Agents) architecture with a mobile agent (MA) that successively queries the sensors lying inside its field of view. We propose both fast/simple and optimal DOA-estimation schemes, and an optimization of the MAs observation management is also carried out, with the surprising finding that the MA ought to orient itself at an oblique angle to the expected DOA, rather than directly toward it. We also consider the extension to multiple sources; intriguingly, per-source DOA accuracy is higher when there is more than one source. In all cases, performance is investigated by simulation and compared, when appropriate, with asymptotic bounds; these latter are usually met after a moderate number of MA dwells. In the second topic, we study the problem of tracking multiple targets in large SN. While these networks hold significant potential for surveillance, it is of interest to address fundamental limitations in large-scale implementations. We first introduce a simple analytical tracker performance model. Analysis of this model suggests that scan-based tracking performance improves with increasing numbers of sensors, but only to a certain point beyond which degradation is observed. Correspondingly, we address model-based optimization of the local sensor detection threshold and the number of sensors. Next, we propose a two-stage tracking approach (fuse-before-track) as a possible approach to overcoming the difficulties in large-sensor surveillance, and we illustrate promising performance results with simulated surveillance data. The third topic of this dissertation deals with distributed target detection in SN using Scan Statistics. We introduce a sequential procedure to detect a target with distributed sensors in a two dimensional region. The detection is carried out in a mobile fusion center which successively counts the number of binary decisions reported by local sensors lying inside its moving field of view. This is a two-dimensional scan statistic an emerging tool from the statistics field that has been applied to a variety of anomaly detection problems such as of epidemics or computer intrusion, but that seems to be unfamiliar to the signal processing community. We show that an optimal size of the field of view exists. We compare the sequential two-dimensional scan statistic test and two other tests. We also present results for system level detection. In the last topic we study a Repeated Significance Test (RST) with applications to sequential detection in SN. We introduce a randomly truncated sequential hypothesis test. Using the framework of a RST, we study a sequential test with truncation time based on a random stopping time. Using the Functional Central Limit Theorem (FCLT) for a sequence of statistics, we derive a general result that can be employed in developing a repeated significance test with random sample size. We present effective methods for evaluating accurate approximations for the probability of type I error and the power function. Numerical results are presented to evaluate the accuracy of these approximations. We apply the proposed test to a decentralized sequential detection in sensor networks (SN) with communication constraints. Finally a sequential detection problem with measurements at random times is investigated.

Guerriero, Marco

155

Neural mechanisms of spatiotemporal signal processing  

NASA Astrophysics Data System (ADS)

We have studied the synaptic, dendritic, and network mechanisms of spatiotemporal signal processing underlying the computation of visual motion in the avian tectum. Such mechanisms are critical for information processing in all vertebrates, but have been difficult to elucidate in mammals because of anatomical limitations. We have therefore developed a chick tectal slice preparation, which has features that help us circumvent these limitations. Using single-electrode multi-pulse synaptic stimulation experiments we found that the SGC-I cell responds to synaptic stimulation in a binary manner and its response is phasic in a time dependent probabilistic manner over large time scales. Synaptic inputs at two locations typically interact in a mutually exclusive manner when delivered within the "interaction time" of approximately 30 ms. Then we constructed a model of SGC-I cell and the retinal inputs to examine the role of the observed non-linear cellular properties in shaping the response of SGC-I neurons to assumed retinal representations of dynamic spatiotemporal visual stimuli. We found that by these properties, SGC-I cells can classify different stimuli. Especially without the phasic synaptic signal transfer the model SGC-I cell fails to distinguish between the static stationary stimuli and dynamic spatiotemporal stimuli. Based on one-site synaptic response probability and the assumption of independent neighboring dendritic endings we predicted the response probability of SGC-I cells to multiple synaptic inputs. We tested this independence-based model prediction and found that the independency assumption is not valid. The measured SGC-I response probability to multiple synaptic inputs does not increase with the number of synaptic inputs. The presence of GABAergic horizontal cells in layer 5 suggest an inhibitory effect of these cells on the SGC-I retino-tectal synaptic responses. In our experiment we found that the measured SGC-I response probability to multiple synaptic inputs is reduced when inhibitory tectal circuits are blocked. By predicting the SGC-I response to multiple synaptic inputs based on blocked inhibitory circuitry we found that the response probability is closer to independent situation but not exactly. So there is more than just inhibitory mechanism involved. To characterize the dependency between two neighboring synapses we used 2-site stimulation experiments and measured the effect of one stimulation on a spatially separate synapse. To determine whether this inhibitory mechanism is pre-synaptic or post-synaptic we used chloride channel blocker intracellularly. We saw an increase in response probability when post-synaptic chloride channels are blocked. Finally we found a good agreement between our prediction and experimental results for Poisson spike trains which may be considered more natural stimuli. Only the early stage of SGC-I response is carrying most of the information. Analyzing the SGC-I spike timing and the accuracy of latency is the last part of the thesis.

Khanbabaie Shoub, Shaban (Reza)

156

PASSIVE SENSOR IMAGING USING CROSS CORRELATIONS OF NOISY SIGNALS IN A SCATTERING MEDIUM  

E-print Network

PASSIVE SENSOR IMAGING USING CROSS CORRELATIONS OF NOISY SIGNALS IN A SCATTERING MEDIUM JOSSELIN's function between two passive sensors can be estimated from the cross correlation of recorded signal that the travel time can be effectively estimated when the ray joining the two sensors continues into the noise

Garnier, Josselin

157

Neural Correlates of Cognitive Processes LIDA Module  

E-print Network

et al 2006 Sensory Memory Temporal- prefrontal (echoic) Alain et al, 1998 Slipnet Perceptual Associative Memory (PAM) Perirhinal Cortex Davachi et al 2003 Freeman, 2003 Slipnet object nodes PAM olfaction and emotion nodes PAM-Olfactory reward & punishment signals Mushroom body neurons & dorsal paired

Memphis, University of

158

Adaptive Noise Suppression Using Digital Signal Processing  

NASA Technical Reports Server (NTRS)

A signal to noise ratio dependent adaptive spectral subtraction algorithm is developed to eliminate noise from noise corrupted speech signals. The algorithm determines the signal to noise ratio and adjusts the spectral subtraction proportion appropriately. After spectra subtraction low amplitude signals are squelched. A single microphone is used to obtain both eh noise corrupted speech and the average noise estimate. This is done by determining if the frame of data being sampled is a voiced or unvoiced frame. During unvoice frames an estimate of the noise is obtained. A running average of the noise is used to approximate the expected value of the noise. Applications include the emergency egress vehicle and the crawler transporter.

Kozel, David; Nelson, Richard

1996-01-01

159

Development of an Ontology-Directed Signal Processing Toolbox  

SciTech Connect

This project was focused on the development of tools for the automatic configuration of signal processing systems. The goal is to develop tools that will be useful in a variety of Government and commercial areas and useable by people who are not signal processing experts. In order to get the most benefit from signal processing techniques, deep technical expertise is often required in order to select appropriate algorithms, combine them into a processing chain, and tune algorithm parameters for best performance on a specific problem. Therefore a significant benefit would result from the assembly of a toolbox of processing algorithms that has been selected for their effectiveness in a group of related problem areas, along with the means to allow people who are not signal processing experts to reliably select, combine, and tune these algorithms to solve specific problems. Defining a vocabulary for problem domain experts that is sufficiently expressive to drive the configuration of signal processing functions will allow the expertise of signal processing experts to be captured in rules for automated configuration. In order to test the feasibility of this approach, we addressed a lightning classification problem, which was proposed by DOE as a surrogate for problems encountered in nuclear nonproliferation data processing. We coded a toolbox of low-level signal processing algorithms for extracting features of RF waveforms, and demonstrated a prototype tool for screening data. We showed examples of using the tool for expediting the generation of ground-truth metadata, for training a signal recognizer, and for searching for signals with particular characteristics. The public benefits of this approach, if successful, will accrue to Government and commercial activities that face the same general problem - the development of sensor systems for complex environments. It will enable problem domain experts (e.g. analysts) to construct signal and image processing chains without the aid of signal processing experts. Thus enabled, problem domain experts will be able to work more quickly and produce better quality work.

Stephen W. Lang

2011-05-27

160

Beam-steering of receiving array antenna using local signal beamformer by optical signal processing  

Microsoft Academic Search

Beam-steering of receiving array antenna using local signal beamformer by optical signal processing is demonstrated in the X-band. The arriving direction of RF beam is recognized from the location of the light in the optical signal processor

Tomohiro Akiyama; Keizo Inagaki; Y. Mizuguchi

2000-01-01

161

Frequency domain laser velocimeter signal processor: A new signal processing scheme  

NASA Technical Reports Server (NTRS)

A new scheme for processing signals from laser velocimeter systems is described. The technique utilizes the capabilities of advanced digital electronics to yield a smart instrument that is able to configure itself, based on the characteristics of the input signals, for optimum measurement accuracy. The signal processor is composed of a high-speed 2-bit transient recorder for signal capture and a combination of adaptive digital filters with energy and/or zero crossing detection signal processing. The system is designed to accept signals with frequencies up to 100 MHz with standard deviations up to 20 percent of the average signal frequency. Results from comparative simulation studies indicate measurement accuracies 2.5 times better than with a high-speed burst counter, from signals with as few as 150 photons per burst.

Meyers, James F.; Clemmons, James I., Jr.

1987-01-01

162

Signal processing at the Poker Flat MST radar  

NASA Technical Reports Server (NTRS)

Signal processing for Mesosphere-Stratosphere-Troposphere (MST) radar is carried out by a combination of hardware in high-speed, special-purpose devices and software in a general-purpose, minicomputer/array processor. A block diagram of the signal processing system is presented, and the steps in the processing pathway are described. The current processing capabilities are given, and a system offering greater coherent integration speed is advanced which hinges upon a high speed preprocessor.

Carter, D. A.

1983-01-01

163

Volterra Series Based Signal Processing on Integrated Communication Systems  

E-print Network

of the circuit does not depend upon its previous history. In power series, all the coefficients a1, a2Volterra Series Based Signal Processing on Integrated Communication Systems Chunchen Liu1-modulation distortions and harmonic distortions in high frequency signal processing environments based on Volterra series

Fan, Jeffrey

164

Statistical Signal processing for an implantable ethanol biosensor  

Microsoft Academic Search

The understanding of drinking patterns leading to alcoholism has been hindered by an inability to unobtrusively measure ethanol consumption over periods of weeks to months in the community environment. Signal processing for an implantable ethanol MEMS bio sensor under simultaneous development is described where the sensor-signal processing system will provide a novel approach to this need. For safety and user

Jae-Joon Han; Peter C. Doerschuk; Saul B. Gelfand; S. J. O'Connor

2006-01-01

165

High level software synthesis for signal processing systems  

Microsoft Academic Search

For the design of complex digital signal processing systems, block diagram oriented simulation has become a widely accepted standard. Current research is concerned with the coupling of heterogenous simulation engines and the transition from simulation to the implementation of digital signal processing systems. Due to the difficulty in mastering complex design spaces high level hardware and software synthesis is becoming

Sebastian Ritz; M. Pankert; Heinrich Meyr

1992-01-01

166

Low power signal processing architectures for network microsensors  

Microsoft Academic Search

Low power signal processing systems are required for distributed network microsensor techn- ology. Network microsensors now provide a new monitoring and control capability for civil and military applications in transportation, manufacturing, biomed- ical technology, environmental management, and safety and security systems. Signal processing methods for event detection have been developed with low power, parallel architectures that optimize performance for unique

Michael J. Dong; K. Geoffrey Yung; William J. Kaiser

1997-01-01

167

A review of signal processing in brain computer interface system  

Microsoft Academic Search

Brain computer interface system incorporating signal processing techniques augments human capabilities by providing a new interaction link with the outside world and is particularly relevant as an aid for paralyzed humans, and even for able-bodied people. This paper describes the essential components of BCI system, types and signal processing techniques used in the system. Several methods of electrode placement, filtering,

N. A. M. Norani; W. Mansor; L. Y. Khuan

2010-01-01

168

Wireless transceivers for mobile terminals: architectures, analysis and signal processing  

E-print Network

Wireless transceivers for mobile terminals: architectures, analysis and signal processing Lead: G components). Theoretical analysis of components impairments of the performances of these architectures. - Use-radio transmitter Frequency synthesis and PLL (Phase Locked loop) using digital signal processing for multistandard

Baudoin, Geneviève

169

Signal acquisition and processing in medical diagnostic ultrasound  

Microsoft Academic Search

As uses for ultrasound increase, so does the need for effective signal processing techniques. In this article we provide an overview of signal acquisition and processing in modern medical ultrasound imaging equipment and present some of the more important concepts in practice today. Images and data types typical of current ultrasound equipment are reviewed; fundamental acoustics and design parameters that

J. U. Quistgaard

1997-01-01

170

Informatics and Mathematical Modelling / Intelligent Signal Processing 1Jan Larsen  

E-print Network

Informatics and Mathematical Modelling / Intelligent Signal Processing 1Jan Larsen Statistical framework for decision making in mine action Jan Larsen Intelligent Signal Processing Group Informatics and Mathematical Modelling Technical University of Denmark jl@imm.dtu.dk, www.imm.dtu.dk/~jl #12;Jan Larsen 2

171

Analogue neural network design for the processing of measurement signals  

Microsoft Academic Search

This paper deals with a new design method for the analogue processing and generation of signals in measurement instruments. The method is based on the observation that in each processing procedure the operations to be performed on the input signal are represented by simple mathematical and control function blocks in a flow diagram. The paper shows how each block can

Pasquale Daponte; Domenico Grimaldi; Linus Michaeli

1999-01-01

172

Electrophysiological Correlates of Second Language Processing  

ERIC Educational Resources Information Center

The aim of this article is to provide a selective review of event-related potential (ERP) research on second language processing. As ERPs have been used in the investigation of a variety of linguistic domains, the reported studies cover different paradigms assessing processing mechanisms in the second language at various levels, ranging from…

Mueller, Jutta L.

2005-01-01

173

Signal subspace analysis for decoherent processes during interferometric fiber-optic gyroscopes using synchronous adaptive filters.  

PubMed

Conventional signal processing methods for improving the random walk coefficient and the bias stability of interferometric fiber-optic gyroscopes are usually implemented in one-dimension sequence. In this paper, as a comparison, we allocated synchronous adaptive filters with the calculations of correlations of multidimensional signals in the perspective of the signal subspace. First, two synchronous independent channels are obtained through quadrature demodulation. Next, synchronous adaptive filters were carried out in order to project the original channels to the high related error channels and the approximation channels. The error channel signals were then processed by principal component analysis for suppressing coherent noises. Finally, an optimal state estimation of these error channels and approximation channels based on the Kalman gain coefficient was operated. Experimental results show that this signal processing method improved the raw measurements' variance from 0.0630?[(°/h)2] to 0.0103?[(°/h)2]. PMID:25322393

Li, Yongxiao; Wang, Zinan; Peng, Chao; Li, Zhengbin

2014-10-10

174

Surface EMG signal processing during isometric contractions  

Microsoft Academic Search

This paper provides an overview of techniques suitable for the estimation, interpretation and understanding of time variations that affect the surface electromyographic (EMG) signal during sustained voluntary or electrically elicited contractions. These variations concern amplitude variables, spectral variables and muscle fiber conduction velocity, are interdependent and are referred to as the `fatigue plot'. The fatigue plot provides information suitable for

Roberto Merletti; Loredana R. Lo Conte

1997-01-01

175

Anawake: Signal-Based Power Management For Digital Signal Processing Systems  

E-print Network

@sst.ll.mit.edu Abstract Single-chip, low-power, programmable digital signal processing sys- tems are capable of hosting. 1. Introduction Single-chip programmable digital signal processing (DSP) systems (Figure 1 applications such as small-vocabulary, speaker- independent speech recognition. An example is a single-chip DSP

Lazzaro, John

176

Real time all optical correlator for serialized time encoded signals  

NASA Astrophysics Data System (ADS)

A novel technique for correlation of spectrally encoded data is presented. Data encoded in the spectrum of ultrafast optical pulses is mapped into the time domain using dispersion and then mixed with a spectrally engineered broadband pump using four wave mixing to create a narrow bandwidth idler, which is isolated and electronically integrated. Unlike previous methods, this solution provides all-optical functionality at every stage of correlation. The demonstrated frame rate of 20 MHz is limited only by the laser repetition rate.

Shoeiby, Mehrdad; Mitchell, Arnan; Bui, Lam

2015-03-01

177

Classification of no-signaling correlation and the "guess your neighbor's input" game  

NASA Astrophysics Data System (ADS)

We formulate a series of nontrivial equalities which are satisfied by all no-signaling correlations, meaning that no faster-than-light communication is allowed with the resource of these correlations. All quantum and classical correlations satisfy these equalities since they are no-signaling. By applying these equalities, we provide a general framework for solving the multipartite "guess your neighbor's input" (GYNI) game, which is naturally no-signaling but shows conversely that general no-signaling correlations are actually more nonlocal than those allowed by quantum mechanics. We confirm the validity of our method for the number of players from 3 up to 19, thus providing convincing evidence that it works for the general case. In addition, we solve analytically the tripartite GYNI and obtain a computable measure of supraquantum correlations. This result simplifies the defined optimization procedure to an analytic formula, thus characterizing explicitly the boundary between quantum and supraquantum correlations. In addition, we show that the gap between quantum and no-signaling boundaries containing supraquantum correlations can be closed by local orthogonality conditions in the tripartite case. Our results provide a computable classification of no-signaling correlations.

Wang, He-Ming; Zhou, Heng-Yun; Mu, Liang-Zhu; Fan, Heng

2014-09-01

178

Pulsed laser ranging techniques based on digital signal processing methods for automobile anti-collision application  

Microsoft Academic Search

A 1.55 µm digital laser radar system is designed and implemented for automobile anti-collision application. In order to reduce the influence of foggy, rainy and snowy weather on laser detection, digital signal processing methods are adopted. Multi-pulse coherent average algorithm is used to improve the signal-to-noise ratio of echo by N times. The correlation detection algorithm is adopted to estimate

Zhihui Sun; Jiahao Deng

2008-01-01

179

Moving source localization using seismic signal processing  

NASA Astrophysics Data System (ADS)

Accurate localization of a seismic source in a near-field scenario where the distances between sensors and the source are less than a few wavelengths of the generated signal has shown to be a challenging task. Conventional localization algorithms often prove to be ineffective, as near-field seismic signals exhibit characteristics different from the well-studied far-field signals. The current work is aimed at the employment of a seismic sensor array for the localization and tracking of a near-field wideband moving source. In this paper, the mathematical derivation of a novel DOA estimation algorithm-dubbed the Modified Kirlin Method-has been presented in details. The estimated DOAs are then combined using a least-squares optimization method for source localization. The performance of the proposed method has been evaluated in a field experiment to track a moving truck. We also compare the DOA estimation and source localization results of the proposed method with those of two other existing methods originally developed for localization of a stationary wideband source; Covariance Matrix Analysis and the Surface Wave Analysis. Our results indicate that both the Surface Wave Analysis and the Modified Kirlin Methods are effective in locating and tracking a moving truck.

Asgari, Shadnaz; Stafsudd, Jing Z.; Hudson, Ralph E.; Yao, Kung; Taciroglu, Ertugrul

2015-01-01

180

Processing electrophysiological signals for the monitoring of alertness  

NASA Technical Reports Server (NTRS)

Mathematical techniques are described for processing EEG signals associated with varying states of alertness. Fast algorithms for implementing real-time computations of alertness estimates were developed. A realization of the phase-distortionless digital filter is presented which approaches real-time filtering and a transform for EEG signals. This transform provides information for the alertness estimates and can be performed in real time. A statistical test for stationarity in EEG signals is being developed that will provide a method for determining the duration of the EEG signals necessary for estimating the short-time power or energy spectra for nonstationary analysis of EEG signals.

Lai, D. C.

1974-01-01

181

Neuromorphic opto-electronic integrated circuits for optical signal processing  

NASA Astrophysics Data System (ADS)

The ability to produce narrow optical pulses has been extensively investigated in laser systems with promising applications in photonics such as clock recovery, pulse reshaping, and recently in photonics artificial neural networks using spiking signal processing. Here, we investigate a neuromorphic opto-electronic integrated circuit (NOEIC) comprising a semiconductor laser driven by a resonant tunneling diode (RTD) photo-detector operating at telecommunication (1550 nm) wavelengths capable of excitable spiking signal generation in response to optical and electrical control signals. The RTD-NOEIC mimics biologically inspired neuronal phenomena and possesses high-speed response and potential for monolithic integration for optical signal processing applications.

Romeira, B.; Javaloyes, J.; Balle, S.; Piro, O.; Avó, R.; Figueiredo, J. M. L.

2014-08-01

182

Electrophysiological Correlates of Stimulus Equivalence Processes  

ERIC Educational Resources Information Center

Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

2009-01-01

183

Correlates of linguistic rhythm in the speech signal  

Microsoft Academic Search

Spoken languages have been classified by linguists according to their rhythmic properties, and psycholinguists have relied on this classification to account for infants’ capacity to discriminate languages. Although researchers have measured many speech signal properties, they have failed to identify reliable acoustic characteristics for language classes. This paper presents instrumental measurements based on a consonant\\/vowel segmentation for eight languages. The

Franck Ramus; Marina Nespor; Jacques Mehler

1999-01-01

184

An approach for physiological signal processing by laboratory minicomputer.  

PubMed

Physiological signal-processing instrumentation including the digital oscilloscope is becoming more dependent upon the microprocessor. Minicomputer software has been developed which demonstrates data-processing approaches that should be considered for incorporation into the firmware of digital oscilloscopes. This core-resident software called DATAC operates in an interpretive mode and provides such features as digital signal editing, filtering, and basic processing including differentiation and integration. PMID:639498

Tompkins, W J

1978-03-01

185

On the Development of Analogue Sampled-Data Signal Processing  

Microsoft Academic Search

This paper provides a historical perspective on thedevelopment of analogue sampled-data signal processing circuitsand systems. The evolution, role and current trends in the developmentof analogue sampled-data signal processing systems is surveyed.Firstly, the evolution of integrated circuit based techniques,culminating in the ubiquitous switched-capacitor technique istraced. Then the role that analogue sampled-data systems playwithin the context of a general information processing environmentis

Gerson A. S. Machado; Nicholas C. Battersby; Chris Toumazou

1997-01-01

186

Mixed-correlated ARFIMA processes for power-law cross-correlations  

NASA Astrophysics Data System (ADS)

We introduce a general framework of the Mixed-correlated ARFIMA (MC-ARFIMA) processes which allows for various specifications of univariate and bivariate long-term memory. Apart from a standard case when H={1}/{2}(Hx+Hy), MC-ARFIMA also allows for processes with H<{1}/{2}(Hx+Hy) but also for long-range correlated processes which are either short-range cross-correlated or simply correlated. The major contribution of MC-ARFIMA lies in the fact that the processes have well-defined asymptotic properties for Hx, Hy and H, which are derived in the paper, so that the processes can be used in simulation studies comparing various estimators of the bivariate Hurst exponent H. Moreover, the framework allows for modeling of processes which are found to have H<{1}/{2}(Hx+Hy).

Kristoufek, Ladislav

2013-12-01

187

Quantifying time-varying coordination of multimodal speech signals using correlation map analysis.  

PubMed

This paper demonstrates an algorithm for computing the instantaneous correlation coefficient between two signals. The algorithm is the computational engine for analyzing the time-varying coordination between signals, which is called correlation map analysis (CMA). Correlation is computed around any pair of points in the two input signals. Thus, coordination can be assessed across a continuous range of temporal offsets and be detected even when changing over time due to temporal fluctuations. The correlation algorithm has two major features: (i) it is structurally similar to a tunable filter, requiring only one parameter to set its cutoff frequency (and sensitivity), (ii) it can be applied either uni-directionally (computing correlation based only on previous samples) or bi-directionally (computing correlation based on both previous and future samples). Computing instantaneous correlation for a range of time offsets between two signals produces a 2D correlation map, in which correlation is characterized as a function of time and temporal offset. Graphic visualization of the correlation map provides rapid assessment of how correspondence patterns progress through time. The utility of the algorithm and of CMA are exemplified using the spatial and temporal coordination of various audible and visible components associated with linguistic performance. PMID:22423712

Barbosa, Adriano Vilela; Déchaine, Rose-Marie; Vatikiotis-Bateson, Eric; Yehia, Hani Camille

2012-03-01

188

Smoke-detector signal micrologic processing circuit  

Microsoft Academic Search

We have proposed a new simple single processing circuit on the basis of micrologic included logic NAND and OR-AND cells for an absorption type smoke-detector. The principle of the operation of the circuit is described. The merits and deficiences of such processing circuits are discussed.

V. M Aroutiounian; Z. N Adamian; M. S Panossian; A. A Barseghyan

1996-01-01

189

Waveform Diversity in Radar Signal Processing  

Microsoft Academic Search

This article shows that suitably transmitted and processed, radar waveforms based on Golay sequences provide new primitives for adaptive transmission that enable better detection and finer resolution, while managing computational complexity at the receiver. The ability to exploit space-time adaptive processing is limited by the computational power available at the receiver, and increased flexibility on transmission only exacerbates this problem

R. Calderbank; S. Howard; B. Moran

2009-01-01

190

Grating geophone signal processing based on wavelet transform  

NASA Astrophysics Data System (ADS)

Grating digital geophone is designed based on grating measurement technique benefiting averaging-error effect and wide dynamic range to improve weak signal detected precision. This paper introduced the principle of grating digital geophone and its post signal processing system. The signal acquisition circuit use Atmega 32 chip as core part and display the waveform on the Labwindows through the RS232 data link. Wavelet transform is adopted this paper to filter the grating digital geophone' output signal since the signal is unstable. This data processing method is compared with the FIR filter that widespread use in current domestic. The result indicates that the wavelet algorithm has more advantages and the SNR of seismic signal improve obviously.

Li, Shuqing; Zhang, Huan; Tao, Zhifei

2008-12-01

191

Preliminary development of digital signal processing in microwave radiometers  

NASA Technical Reports Server (NTRS)

Topics covered involve a number of closely related tasks including: the development of several control loop and dynamic noise model computer programs for simulating microwave radiometer measurements; computer modeling of an existing stepped frequency radiometer in an effort to determine its optimum operational characteristics; investigation of the classical second order analog control loop to determine its ability to reduce the estimation error in a microwave radiometer; investigation of several digital signal processing unit designs; initiation of efforts to develop required hardware and software for implementation of the digital signal processing unit; and investigation of the general characteristics and peculiarities of digital processing noiselike microwave radiometer signals.

Stanley, W. D.

1980-01-01

192

Methods and analysis of processing signals of incremental optoelectronic transducer.  

PubMed

This article is a presentation of designed methods which interpolate signals from the optoelectronic transducer. This enables a way to distinguish the motion direction of the optoelectronic transducer and also to increase its accuracy. In this article methods based on logic functions, logic functions and RC circuits, phase processing were analyzed. In methods which are based on processing logic functions of transducer's signals there is a possibility of two times and four times increase in the transducer glass scale. The presented method of generating and processing sine signals with 18 degrees of the shift enables the reception of square signals with five times higher frequency compared to the basic signals. This method is universal and it can be used to the different scale of frequency multiplication of the optoelectronic transducer. The simulations of the methods were performed by using the MATLAB-SIMULINK software. PMID:19791953

Szcze?niak, Adam; Szcze?niak, Zbigniew

2009-09-01

193

Modeling laser velocimeter signals as triply stochastic Poisson processes  

NASA Technical Reports Server (NTRS)

Previous models of laser Doppler velocimeter (LDV) systems have not adequately described dual-scatter signals in a manner useful for analysis and simulation of low-level photon-limited signals. At low photon rates, an LDV signal at the output of a photomultiplier tube is a compound nonhomogeneous filtered Poisson process, whose intensity function is another (slower) Poisson process with the nonstationary rate and frequency parameters controlled by a random flow (slowest) process. In the present paper, generalized Poisson shot noise models are developed for low-level LDV signals. Theoretical results useful in detection error analysis and simulation are presented, along with measurements of burst amplitude statistics. Computer generated simulations illustrate the difference between Gaussian and Poisson models of low-level signals.

Mayo, W. T., Jr.

1976-01-01

194

Time reversal signal processing for communication.  

SciTech Connect

Time-reversal is a wave focusing technique that makes use of the reciprocity of wireless propagation channels. It works particularly well in a cluttered environment with associated multipath reflection. This technique uses the multipath in the environment to increase focusing ability. Time-reversal can also be used to null signals, either to reduce unintentional interference or to prevent eavesdropping. It does not require controlled geometric placement of the transmit antennas. Unlike existing techniques it can work without line-of-sight. We have explored the performance of time-reversal focusing in a variety of simulated environments. We have also developed new algorithms to simultaneously focus at a location while nulling at an eavesdropper location. We have experimentally verified these techniques in a realistic cluttered environment.

Young, Derek P.; Jacklin, Neil; Punnoose, Ratish J.; Counsil, David T.

2011-09-01

195

Digital methods of the optimum processing of radar signals  

Microsoft Academic Search

In book questions of use\\/application of digital computers for optimum processing of radar signals are examined. Primary attention is given to the detection of signals from the targets, hidden by interferences, and to the determination of the target coordinates. Is described the work of the simplest diagrams of working\\/treatment, their operating principle, and also work of some nodes of digital

S. V. Samsonenko

1985-01-01

196

Gaussian Processes for Signal Strength-Based Location Estimation  

Microsoft Academic Search

Estimating the location of a mobile device or a robot from wireless signal strength has become an area of highly active research. The key problem in this context stems from the complexity of how signals propagate through space, especially in the presence of obstacles such as buildings, walls or people. In this paper we show how Gaussian processes can be

Brian Ferris; Dirk Hähnel; Dieter Fox

2006-01-01

197

Social Signal Processing: Survey of an Emerging Domain  

E-print Network

social intelligence and none will need all of the related skills humans have. The currentSocial Signal Processing: Survey of an Emerging Domain Alessandro Vinciarelli a,b Maja Pantic c The ability to understand and manage social signals of a person we are communi- cating with is the core

198

Robust Microphone Array Signal Processing against Diffuse Noise  

E-print Network

Robust Microphone Array Signal Processing against Diffuse Noise ( ) Nobutaka Ito tel-00691931 Suppression for Target Signal from Known Direc- tion 47 4.1 Unified framework for diffuse noise suppression of Directions of Arrival of Target Sig- nals 60 5.1 Unified framework based on low-rank matrix completion

Paris-Sud XI, Université de

199

dsp history IEEE SIGNAL PROCESSING MAGAZINE118 MARCH 2004  

E-print Network

of 1968 when I ran into Charlie Rader from MIT Lincoln Laboratory. Charlie had become a good friend in the IEEE Signal Processing Group, a subgroup of IEEE's group on audio and elec- troacoustics. Charlie asked by appro- priate signal weighting to reduce the formant bandwidth. Charlie asked me to define what I would

Liebling, Michael

200

Analog Integrated Circuits Design for Processing Physiological Signals  

Microsoft Academic Search

Analog integrated circuits (ICs) designed for processing physiological signals are important building blocks of wearable and implantable medical devices used for health monitoring or restoring lost body functions. Due to the nature of physiological signals and the corresponding application scenarios, the ICs designed for these applications should have low power consumption, low cutoff frequency, and low input-referred noise. In this

Yan Li; Carmen C. Y. Poon; Yuan-Ting Zhang

2010-01-01

201

Relationships between digital signal processing and control and estimation theory  

NASA Technical Reports Server (NTRS)

Research areas associated with digital signal processing and control and estimation theory are identified. Particular attention is given to image processing, system identification problems (parameter identification, linear prediction, least squares, Kalman filtering), stability analyses (the use of the Liapunov theory, frequency domain criteria, passivity), and multiparameter systems, distributed processes, and random fields.

Willsky, A. S.

1978-01-01

202

On correlation signal detection with particular reference to an application in sonar  

Microsoft Academic Search

Correlation detectors operate by exploiting the similarity between two waveforms, one of which is the signal to be detected and the other of which is a reference waveform. In practice the similarity occurs because both waveforms will have been derived from the same source. As a measure of the similarity between two signals, a similarity function is introduced which is

M. J. Buckingham

1977-01-01

203

STATISTICAL SIGNAL PROCESSING APPROACHES TO FAULT DETECTION  

E-print Network

processing. It is motivated by three applications that a simple CUSUM detector in feedback loop, principal component analysis, subspace identification 1. INTRODUCTION The parity space approach to fault as Princi- pal Component Analysis (PCA). · The use and fusion of residuals from several independent models

Gustafsson, Fredrik

204

Signal processing in biological cells : proteins, networks, and models  

E-print Network

This thesis introduces systematic engineering principles to model, at different levels of abstraction the information processing in biological cells in order to understand the algorithms implemented by the signaling pathways ...

Said, Maya Rida, 1976-

2005-01-01

205

An Energy-Efficient Biomedical Signal Processing Platform  

E-print Network

This paper presents an energy-efficient processing platform for wearable sensor nodes, designed to support diverse biological signals and algorithms. The platform features a 0.5V-1.0V 16b microcontroller, SRAM, and ...

Kwong, Joyce

206

Sensitivity of polynomial composition and decomposition for signal processing applications  

E-print Network

Polynomial composition is well studied in mathematics but has only been exploited indirectly and informally in signal processing. Potential future application of polynomial composition for filter implementation and data ...

Demirtas, Sefa

207

HYPERSPECTRAL IMAGING: SIGNAL PROCESSING ALGORITHM DESIGN AND ANALYSIS  

E-print Network

HYPERSPECTRAL IMAGING: SIGNAL PROCESSING ALGORITHM DESIGN AND ANALYSIS Chein-I Chang Remote Sensing: Independent Component Analysis-Based Abundance Quantification PART V: HYPERSPECTRAL IMAGE COMPRESSION Chapter Chapter 19: Spectral/Spatial Hyperspectral Image Compression Chapter 20: Hyperspectral Information

Chang, Chein-I

208

A survey of signal processing algorithms in brain–computer interfaces based on electrical brain signals  

Microsoft Academic Search

Brain–computer interfaces (BCIs) aim at providing a non-muscular channel for sending commands to the external world using the electroencephalographic activity or other electrophysiological measures of the brain function. An essential factor in the successful operation of BCI systems is the methods used to process the brain signals. In the BCI literature, however, there is no comprehensive review of the signal

Ali Bashashati; Mehrdad Fatourechi; Rabab K Ward; Gary E Birch

2007-01-01

209

Fluctuations and correlations as a signal of deconfinement  

SciTech Connect

Event-by-event fluctuations of the K/{pi}, K/p, and p/{pi} ratio in central AA collisions have been studied for SPS and RHIC energies. The Hadron-String-Dynamical transport approach (HSD) can qualitatively reproduce the measured excitation function for the K/{pi} ratio fluctuations. The di-jet azimuthal correlations also have been investigated within the HSD model. We found that the suppression of the away-side jet in the hadronic mediumis not enough to explain the experimental data from RHIC. The additional suppression should be attributed to a quark-gluon plasma produced in heavy-ion collisions.

Konchakovski, V. P., E-mail: konchakovski@theo.physik.uni-giessen.de [Giessen University, Institute for Theoretical Physics (Germany); Bratkovskaya, E. L. [Frankfurt University, Institute for Theoretical Physics (Germany); Cassing, W. [Giessen University, Institute for Theoretical Physics (Germany); Gorenstein, M. I. [Bogolyobov Institute for Theoretical Physics (Ukraine)

2012-06-15

210

Native signal processing on the Ultrasparc in the Ptolemy environment  

Microsoft Academic Search

We have implemented a number of real-time signal processing kernels and applications within the Ptolemy simulation and code generation environment. Our goal is to make it easy to generate real-time programs with configurable interactive user interfaces. As part of this project, we have developed and benchmarked some key signal processing kernels for the new UltraSparc Visual Instruction Set. We present

William Chen; H. John Reekie; Sunil Bhave; Edward A. Lee

1996-01-01

211

All-optical signal processing using dynamic Brillouin gratings  

PubMed Central

The manipulation of dynamic Brillouin gratings in optical fibers is demonstrated to be an extremely flexible technique to achieve, with a single experimental setup, several all-optical signal processing functions. In particular, all-optical time differentiation, time integration and true time reversal are theoretically predicted, and then numerically and experimentally demonstrated. The technique can be exploited to process both photonic and ultra-wide band microwave signals, so enabling many applications in photonics and in radio science. PMID:23549159

Santagiustina, Marco; Chin, Sanghoon; Primerov, Nicolay; Ursini, Leonora; Thévenaz, Luc

2013-01-01

212

Hybrid digital signal processing and neural networks applications in PWRs  

SciTech Connect

Signal validation and plant subsystem tracking in power and process industries require the prediction of one or more state variables. Both heteroassociative and auotassociative neural networks were applied for characterizing relationships among sets of signals. A multi-layer neural network paradigm was applied for sensor and process monitoring in a Pressurized Water Reactor (PWR). This nonlinear interpolation technique was found to be very effective for these applications.

Eryurek, E.; Upadhyaya, B.R.; Kavaklioglu, K.

1991-01-01

213

Hybrid digital signal processing and neural networks applications in PWRs  

SciTech Connect

Signal validation and plant subsystem tracking in power and process industries require the prediction of one or more state variables. Both heteroassociative and auotassociative neural networks were applied for characterizing relationships among sets of signals. A multi-layer neural network paradigm was applied for sensor and process monitoring in a Pressurized Water Reactor (PWR). This nonlinear interpolation technique was found to be very effective for these applications.

Eryurek, E.; Upadhyaya, B.R.; Kavaklioglu, K.

1991-12-31

214

A coherent nonlinear optical signal induced by electron correlations Shaul Mukamela  

E-print Network

a background-free probe for electronic correlations in many-electron systems. The proposed signal pulse to two pulse delays, provides a direct visualization and specific signatures of the many-electron wave correlations. The tech- nique uses a sequence of three optical pulses with wave vec- tors k1, k2, and k3

Mukamel, Shaul

215

Two-dimensional signal processing with application to image restoration  

NASA Technical Reports Server (NTRS)

A recursive technique for modeling and estimating a two-dimensional signal contaminated by noise is presented. A two-dimensional signal is assumed to be an undistorted picture, where the noise introduces the distortion. Both the signal and the noise are assumed to be wide-sense stationary processes with known statistics. Thus, to estimate the two-dimensional signal is to enhance the picture. The picture representing the two-dimensional signal is converted to one dimension by scanning the image horizontally one line at a time. The scanner output becomes a nonstationary random process due to the periodic nature of the scanner operation. Procedures to obtain a dynamical model corresponding to the autocorrelation function of the scanner output are derived. Utilizing the model, a discrete Kalman estimator is designed to enhance the image.

Assefi, T.

1974-01-01

216

Signal-processing theory for the TurboRogue receiver  

NASA Technical Reports Server (NTRS)

Signal-processing theory for the TurboRogue receiver is presented. The signal form is traced from its formation at the GPS satellite, to the receiver antenna, and then through the various stages of the receiver, including extraction of phase and delay. The analysis treats the effects of ionosphere, troposphere, signal quantization, receiver components, and system noise, covering processing in both the 'code mode' when the P code is not encrypted and in the 'P-codeless mode' when the P code is encrypted. As a possible future improvement to the current analog front end, an example of a highly digital front end is analyzed.

Thomas, J. B.

1995-01-01

217

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING Int. J. Adapt. Control Signal Process. 2011; 25:95113  

E-print Network

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING Int. J. Adapt. Control Signal.com). DOI: 10.1002/acs.1183 Fault-tolerant control allocation for Mars entry vehicle using adaptive control Monika Marwaha¶ and John Valasek,,,§ Vehicle Systems and Control Laboratory, Aerospace Engineering

Valasek, John

218

A Study on Signal Group Processing of AUTOSAR COM Module  

NASA Astrophysics Data System (ADS)

In vehicle, there are many ECU(Electronic Control Unit)s, and ECUs are connected to networks such as CAN, LIN, FlexRay, and so on. AUTOSAR COM(Communication) which is a software platform of AUTOSAR(AUTomotive Open System ARchitecture) in the international industry standards of automotive electronic software processes signals and signal groups for data communications between ECUs. Real-time and reliability are very important for data communications in the vehicle. Therefore, in this paper, we analyze functions of signals and signal groups used in COM, and represent that functions of signal group are more efficient than signals in real-time data synchronization and network resource usage between the sender and receiver.

Lee, Jeong-Hwan; Hwang, Hyun Yong; Han, Tae Man; Ahn, Yong Hak

2013-06-01

219

UCMS - A new signal parameter measurement system using digital signal processing techniques. [User Constraint Measurement System  

NASA Technical Reports Server (NTRS)

The User Constraint Measurement System (UCMS) is a hardware/software package developed by NASA Goddard to measure the signal parameter constraints of the user transponder in the TDRSS environment by means of an all-digital signal sampling technique. An account is presently given of the features of UCMS design and of its performance capabilities and applications; attention is given to such important aspects of the system as RF interface parameter definitions, hardware minimization, the emphasis on offline software signal processing, and end-to-end link performance. Applications to the measurement of other signal parameters are also discussed.

Choi, H. J.; Su, Y. T.

1986-01-01

220

Electrophotonic Devices for Signal Processing and Computing  

Microsoft Academic Search

\\u000a There has recently been much interest in surface-normal optical semiconductor devices for use in short-distance optical interconnection,\\u000a optical switching and information processing. These devices have advantages of small size, low power consumption, and capability\\u000a of twodimensional (2-D) integration due to perpendicular optical input\\/output. There are two kinds of surface-normal semiconductor\\u000a devices. One type includes passive devices such as surface-normal optical

Kenichi Kasahara

221

Optical Correlation of Images With Signal-Dependent Noise Using Constrained-Modulation Filter Devices  

NASA Technical Reports Server (NTRS)

Images with signal-dependent noise present challenges beyond those of images with additive white or colored signal-independent noise in terms of designing the optimal 4-f correlation filter that maximizes correlation-peak signal-to-noise ratio, or combinations of correlation-peak metrics. Determining the proper design becomes more difficult when the filter is to be implemented on a constrained-modulation spatial light modulator device. The design issues involved for updatable optical filters for images with signal-dependent film-grain noise and speckle noise are examined. It is shown that although design of the optimal linear filter in the Fourier domain is impossible for images with signal-dependent noise, proper nonlinear preprocessing of the images allows the application of previously developed design rules for optimal filters to be implemented on constrained-modulation devices. Thus the nonlinear preprocessing becomes necessary for correlation in optical systems with current spatial light modulator technology. These results are illustrated with computer simulations of images with signal-dependent noise correlated with binary-phase-only filters and ternary-phase-amplitude filters.

Downie, John D.

1995-01-01

222

Correlation Processing Of Local Seismic Data: Applications for Autonomous Sensor Deployments  

SciTech Connect

Excavation and operation of an underground facility is likely to produce an extensive suite of seismic signals observable at the surface for perhaps several km. Probably a large fraction of such signals will be correlated, so the design of a monitoring framework should include consideration of a correlation processing capability. Correlation detectors have been shown to be significantly more sensitive than beam-forming power detectors. Although correlation detectors have a limited detection footprint, they can be generalized into multi-rank subspace detectors which are sensitive over a much larger range of source mechanisms and positions. Production of subspace detectors can be automated, so their use in an autonomous framework may be contemplated. Waveform correlation also can be used to produce very high precision phase picks which may be jointly inverted to simultaneously relocate groups of events. The relative precision of the resulting hypocenters is sufficient to visualize structural detail at a scale of less than a few tens of meters. Three possible correlation processor systems are presented. All use a subspace signal detection framework. The simplest system uses a single-component sensor and is capable of detection and classification of signals. The most complicated system uses many sensors deployed around the facility, and is capable of detection, classification, and high-precision source location. Data from a deep underground mine are presented to demonstrate the applicability of correlation processing to monitoring an underground facility. Although the source region covers an area of about 600m by 580m, all but two of the events form clusters at a threshold of 0.7. All the events could have been detected and classified by the subspace detection framework, and high-precision picks can be computed for all cluster members.

Dodge, D A

2010-11-16

223

Signal processing in optical coherence tomography for aerospace material characterization  

NASA Astrophysics Data System (ADS)

Based on a customized time-domain optical coherence tomography (OCT) system, a series of signal processing approaches have been designed and reviewed. To improve demodulation accuracy and image quality, demodulation approaches such as median filter, Hilbert transform, and envelope detector were investigated with simulated as well as experimental data. Without noise, the Hilbert transform has the best performance, but after considering the narrow-band noise in the modulated signal, the envelope detector was selected as the ideal demodulation technique. To reduce noise and enhance image contrast, digital signal processing techniques such as a bandpass filtering and two-dimensional median filtering were applied before and after the demodulation, respectively. Finally with integration of the customized OCT setup and designed signal processing algorithms, aerospace materials, such as polymer coatings and glass-fiber composites, were successfully characterized. The cross-sectional images obtained clearly show the microstructures of the materials.

Liu, Ping; Groves, Roger M.; Benedictus, Rinze

2013-03-01

224

Signal processing method and system for noise removal and signal extraction  

DOEpatents

A signal processing method and system combining smooth level wavelet pre-processing together with artificial neural networks all in the wavelet domain for signal denoising and extraction. Upon receiving a signal corrupted with noise, an n-level decomposition of the signal is performed using a discrete wavelet transform to produce a smooth component and a rough component for each decomposition level. The n.sup.th level smooth component is then inputted into a corresponding neural network pre-trained to filter out noise in that component by pattern recognition in the wavelet domain. Additional rough components, beginning at the highest level, may also be retained and inputted into corresponding neural networks pre-trained to filter out noise in those components also by pattern recognition in the wavelet domain. In any case, an inverse discrete wavelet transform is performed on the combined output from all the neural networks to recover a clean signal back in the time domain.

Fu, Chi Yung (San Francisco, CA); Petrich, Loren (Lebanon, OR)

2009-04-14

225

Correlation dimension analysis of Doppler signals in children with aortic valve disorders.  

PubMed

In this study, the correlation dimension analysis has been applied to the aortic valve Doppler signals to investigate the complexity of the Doppler signals which belong to aortic stenosis (AS) and aortic insufficiency (AI) diseases and healthy case. The Doppler signals of 20 healthy subjects, ten AS and ten AI patients were acquired via the Doppler echocardiography system that is a noninvasive and reliable technique for assessment of AS and AI diseases. The correlation dimension estimations have been performed for different time delay values to investigate the influence of time delay on the correlation dimension calculation. The correlation dimension of healthy group has been found lower those found in AI and AS disorder groups and the correlation dimension of AS group has also been found higher than those found in AI group, significantly. The results of this study have indicated that the aortic valve Doppler signals exhibit high level chaotic behaviour in AI and AS diseases than healthy case. Additionally, the correlation dimension analysis is sensitive to the time delay and has successfully characterized the blood flow dynamics for proper time delay value. As a result, the correlation dimension can be used as an efficient method to determine the healthy or pathological cases of aortic valve. PMID:20703615

Y?lmaz, Derya; Güler, N Fatma

2010-10-01

226

Real-time applications of optical signal processing to command and control communications  

NASA Astrophysics Data System (ADS)

The program reported on in this final report was directed towards development of real-time optical signal processing for C3 and radar applications. Specifically, these applications were A/D conversion, spread spectrum code acquisition and decoding, and clutter rejection in look-down radar. In the context of these applications and through discussions with RADC/ET, technical goals were framed, such as a goal of A/D conversion at 1 Ghz. New optical signal processing techniques were conceived to meet the technical goals. These new approaches include a noncoherent kaleidoscope system for A/D conversion, and a noncoherent optical correlation technique which accommodates the bipolar and complex-valued signals encountered in spread spectrum communications and in radar. During the course of our program, determinations were made of the specific hardware best suited for the testing and demonstration of these novel approaches. These determinations were made by theoretical calculations and by consulting with the literature. Experimental tests of many subsystems, such as the noncoherent correlator optics and acousto-optic Bragg cells for introducing signals into the correlator in real-time, were tested at RADC/ET. Investigations were also made of computer generated holograms for use as pupil masks in the noncoherent correlator.

Stoner, W.; Garber, E.; Horrigan, F.; Collins, G.; Phelps, J.

1980-04-01

227

Analog signal processing for low-power sensor systems  

NASA Astrophysics Data System (ADS)

We present the potential of using Programmable Analog Signal processing techniques for impacting low-power portable applications like imaging, audio processing, and speech recognition. The range of analog signal processing functions available results in many potential opportunities to incorporate these analog signal processing systems with digital signal processing systems for improved overall system performance. We describes our programmable analog technology based around floating-gate transistors that allow for non-volitile storage as well as computation through the same device. We describe the basic concepts for floating-gate devices, capacitor-based circuits, and the basic charge modification mechanisms that makes this analog technology programmable. We describes the techniques to extend these techniques to program an array of floating-gate devices. We show experimental evidence for the factor of 1000 to 10,000 power efficiency improvement for programmable analog signal processing compared to custom digital implementations in Vector Matrix Multipliers (VMM), CMOS imagers with computation on the pixel plane with high fill factors, and Large-Scale Field Programmable Analog Arrays (FPAA), among others.

Hasler, Paul

2006-05-01

228

Low power, compact charge coupled device signal processing system  

NASA Technical Reports Server (NTRS)

A variety of charged coupled devices (CCDs) for performing programmable correlation for preprocessing environmental sensor data preparatory to its transmission to the ground were developed. A total of two separate ICs were developed and a third was evaluated. The first IC was a CCD chirp z transform IC capable of performing a 32 point DFT at frequencies to 1 MHz. All on chip circuitry operated as designed with the exception of the limited dynamic range caused by a fixed pattern noise due to interactions between the digital and analog circuits. The second IC developed was a 64 stage CCD analog/analog correlator for performing time domain correlation. Multiplier errors were found to be less than 1 percent at designed signal levels and less than 0.3 percent at the measured smaller levels. A prototype IC for performing time domain correlation was also evaluated.

Bosshart, P. W.; Buss, D. D.; Eversole, W. L.; Hewes, C. R.; Mayer, D. J.

1980-01-01

229

IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. XX, NO. XX, JANUARY XXXX 1 Relaxed Conditions for Sparse Signal Recovery  

E-print Network

the fundamental doctrine of signal processing has been Shannon's theorem, which states that any continuous signal signals are sparse only in some transform domain (e.g. wavelet), without loss of generality only

230

Signal processing applied to photothermal techniques for materials characterization  

NASA Technical Reports Server (NTRS)

There is a need to make noncontact measurements of material characteristics in the microgravity environment. Photothermal and photoacoustics techniques offer one approach for attaining this capability since lasers can be used to generate the required thermal or acoustic signals. The perturbations in the materials that can be used for characterization can be detected by optical reflectance, infrared detection or laser detection of photoacoustics. However, some of these laser techniques have disadvantages of either high energy pulsed excitation or low signal-to-noise ratio. Alternative signal processing techniques that have been developed can be applied to photothermal or photoacoustic instrumentation. One fully coherent spread spectrum signal processing technique is called time delay spectrometry (TDS). With TDS the system is excited using a combined frequency-time domain by employing a linear frequency sweep excitation function. The processed received signal can provide either frequency, phase or improved time resolution. This signal processing technique was shown to outperform other time selective techniques with respect to noise rejection and was recently applied to photothermal instrumentation. The technique yields the mathematical equivalent of pulses yet the input irradiances are orders of magnitude less than pulses with the concomitant reduction in perturbation of the sample and can increase the capability of photothermal methods for materials characterization.

Rooney, James A.

1989-01-01

231

Collaborative Signal and Information Processing: An Information-Directed Approach  

Microsoft Academic Search

This article describes information-based ap- proaches to processing and organizing spatially distributed, multi-modal sensor data in a sensor network. Energy con- strained networked sensing systems must rely on collabora- tive signal and information processing (CSIP) to dynami- cally allocate resources, maintain multiple sensing foci, and attend to new stimuli of interest, all based on task require- ments and resource constraints.

Zhao Feng; Jie Liu; Juan Julia Liu; Leonidas J. Guibas; James Reich

2003-01-01

232

Relationships between digital signal processing and control and estimation theory  

NASA Technical Reports Server (NTRS)

Research directions in the fields of digital signal processing and modern control and estimation theory are discussed. Stability theory, linear prediction and parameter identification, system synthesis and implementation, two-dimensional filtering, decentralized control and estimation, and image processing are considered in order to uncover some of the basic similarities and differences in the goals, techniques, and philosophy of the disciplines.

Willsky, A. S.

1978-01-01

233

Medical signal processing applications with Motorola's DSP56001  

Microsoft Academic Search

Premature infants in the Neonatal Intensive Care Unit respond to medications and treatments by altering the frequency patterns of their physiological processes. This alteration can be seen in impedance respiratory waveforms, ventilator sensed airway pressure waveforms, electroencephalograms and blood pressure waveforms. The DSP56001 Neonatal Intensive Care Unit (NICU) system is used to record, process and evaluate these signals over long

M. El-Sharkawy; Douglas Sprague

1993-01-01

234

Big Data Analysis with Signal Processing on Graphs  

E-print Network

1 Big Data Analysis with Signal Processing on Graphs Aliaksei Sandryhaila, Member, IEEE and Jos´e M. F. Moura, Fellow, IEEE Analysis and processing of very large datasets, or Big Data, poses sciences to social networks, biomolecular research, commerce and security. Extracting valuable information

Sandryhaila, Aliaksei

235

Genomic Signal Processing: Predicting Basic Molecular Biological Principles  

NASA Astrophysics Data System (ADS)

Advances in high-throughput technologies enable acquisition of different types of molecular biological data, monitoring the flow of biological information as DNA is transcribed to RNA, and RNA is translated to proteins, on a genomic scale. Future discovery in biology and medicine will come from the mathematical modeling of these data, which hold the key to fundamental understanding of life on the molecular level, as well as answers to questions regarding diagnosis, treatment and drug development. Recently we described data-driven models for genome-scale molecular biological data, which use singular value decomposition (SVD) and the comparative generalized SVD (GSVD). Now we describe an integrative data-driven model, which uses pseudoinverse projection (1). We also demonstrate the predictive power of these matrix algebra models (2). The integrative pseudoinverse projection model formulates any number of genome-scale molecular biological data sets in terms of one chosen set of data samples, or of profiles extracted mathematically from data samples, designated the ``basis'' set. The mathematical variables of this integrative model, the pseudoinverse correlation patterns that are uncovered in the data, represent independent processes and corresponding cellular states (such as observed genome-wide effects of known regulators or transcription factors, the biological components of the cellular machinery that generate the genomic signals, and measured samples in which these regulators or transcription factors are over- or underactive). Reconstruction of the data in the basis simulates experimental observation of only the cellular states manifest in the data that correspond to those of the basis. Classification of the data samples according to their reconstruction in the basis, rather than their overall measured profiles, maps the cellular states of the data onto those of the basis, and gives a global picture of the correlations and possibly also causal coordination of these two sets of states. Mapping genome-scale protein binding data using pseudoinverse projection onto patterns of RNA expression data that had been extracted by SVD and GSVD, a novel correlation between DNA replication initiation and RNA transcription during the cell cycle in yeast, that might be due to a previously unknown mechanism of regulation, is predicted. (1) Alter & Golub, Proc. Natl. Acad. Sci. USA 101, 16577 (2004). (2) Alter, Golub, Brown & Botstein, Miami Nat. Biotechnol. Winter Symp. 2004 (www.med.miami.edu/mnbws/alter-.pdf)

Alter, Orly

2005-03-01

236

Optimal and adaptive methods of processing hydroacoustic signals (review)  

NASA Astrophysics Data System (ADS)

Different methods of optimal and adaptive processing of hydroacoustic signals for multipath propagation and scattering are considered. Advantages and drawbacks of the classical adaptive (Capon, MUSIC, and Johnson) algorithms and "fast" projection algorithms are analyzed for the case of multipath propagation and scattering of strong signals. The classical optimal approaches to detecting multipath signals are presented. A mechanism of controlled normalization of strong signals is proposed to automatically detect weak signals. The results of simulating the operation of different detection algorithms for a linear equidistant array under multipath propagation and scattering are presented. An automatic detector is analyzed, which is based on classical or fast projection algorithms, which estimates the background proceeding from median filtering or the method of bilateral spatial contrast.

Malyshkin, G. S.; Sidel'nikov, G. B.

2014-09-01

237

Visualizing confusion matrices for multidimensional signal detection correlational methods  

NASA Astrophysics Data System (ADS)

Advances in modeling and simulation for General Recognition Theory have produced more data than can be easily visualized using traditional techniques. In this area of psychological modeling, domain experts are struggling to find effective ways to compare large-scale simulation results. This paper describes methods that adapt the web-based D3 visualization framework combined with pre-processing tools to enable domain specialists to more easily interpret their data. The D3 framework utilizes Javascript and scalable vector graphics (SVG) to generate visualizations that can run readily within the web browser for domain specialists. Parallel coordinate plots and heat maps were developed for identification-confusion matrix data, and the results were shown to a GRT expert for an informal evaluation of their utility. There is a clear benefit to model interpretation from these visualizations when researchers need to interpret larger amounts of simulated data.

Zhou, Yue; Wischgoll, Thomas; Blaha, Leslie M.; Smith, Ross; Vickery, Rhonda J.

2013-12-01

238

SIG: A general-purpose signal processing program  

NASA Astrophysics Data System (ADS)

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. It also accommodates other representations for data such as transfer function polynomials. Signal processing operations include digital filtering, auto/cross spectral density, transfer function/impulse response, convolution, Fourier transform, and inverse Fourier transform. Graphical operations provide display of signals and spectra, including plotting, cursor zoom, families of curves, and multiple viewport plots. SIG provides two user interfaces with a menu mode for occasional users and a command mode for more experienced users. Capability exits for multiple commands per line, command files with arguments, commenting lines, defining commands, automatic execution for each item in a repeat sequence, etc. SIG is presently available for VAX(VMS), VAX (BERKELEY 4.2 UNIX), SUN (BERKELEY 4.2 UNIX), DEC-20 (TOPS-20), LSI-11/23 (TSX), and DEC PRO 350 (TSX).

Lager, D.; Azevedo, S.

1986-02-01

239

The Influence of Correlated Crustal Signals in Modelling the Main Geomagnetic Field  

NASA Technical Reports Server (NTRS)

Algorithms used in geomagnetic main-field modelling have for the most part treated the noise in the field measurements as if it were white. A major component of the noise consists of the field due to magnetization in the crust and it has been realized for some time that such signals are highly correlated at satellite altitude. Hence approximation by white noise, while of undoubted utility, is of unknown validity. In this paper we study two plausible statistical models for the crustal magnetization, in which the magnetization is a realization of a stationary, isotropic, random process. At a typical satellite altitude the associated fields exhibit significant correlation over ranges as great as 15 deg. or more, which introduces off-diagonal elements into the covariance matrix, elements that have usually been neglected in modelling procedures. Dealing with a full covariance matrix for a large data set would present a formidable computational challenge, but fortunately most of the entries in the covariance matrix are so small that they can be replaced by zeros. The resultant matrix comprises only about 3 per cent non-zero entries and thus we can take advantage of efficient sparse matrix techniques to solve the numerical system. We construct several main-field models based on vertical-component data from a selected 5 deg. by 5 deg. data set derived from the Magsat mission. Models with and without off-diagonal terms are compared.

Rygaard-Hjalsted, C.; Constable, C. G.; Parker, R. L.

1997-01-01

240

On the investigation of the neurophysiological correlates of knowledge worker mental fatigue using the EEG signal.  

PubMed

Technological trends and advances in automation have underscored the importance of task performance of certain jobs requiring mental functions such as information processing and decision analyses. Most experts agree that such work environments produce increased mental activities, with profound implications for mental fatigue and stress. Consequently, productivity measurement and improvement for white collar or 'knowledge worker' occupations remains a major challenge and concern. This investigation defines an experimental approach that examines the neurophysiological correlates of white collar worker mental fatigue using the EEG signal. A 6 h laboratory experiment was conducted to simulate work output. The methods of assessing fatigue employed were mental tests and physiological measurements. The experiment involved reading of standardized texts, finding solutions to arithmetic-logical problems and a combination of both task types. Two primary performance measures were obtained, work output and brain waves. Fast Fourier transform and correlation analyses are used to quantify the relationship between certain brain waves and mental fatigue. This research is a major step towards the development of a model that explores the relationship between mental fatigue and factors associated with output performance, optimal recuperation periods and related variables. Such a model would be useful in human reliability prediction based on task parameters and worker profiles. PMID:15676987

Okogbaa, O G; Shell, R L; Filipusic, D

1994-12-01

241

Probing many-particle correlations in semiconductor quantum wells using double-quantum-coherence signals  

PubMed Central

Multidimensional analysis of coherent signals is commonly used in nuclear magnetic resonance to study correlations among spins. These techniques were recently extended to the femtosecond regime and applied to chemical, biological and semiconductor systems. In this work, we apply a two-dimensional correlation spectroscopy technique which employs double-quantum-coherence to investigate many-body effects in a semiconductor quantum well. The signal is detected along the direction k1+ k2? k3, where k1, k2 and k3 are the pulse wave vectors in chronological order. We show that this signal is particularly sensitive to many-body correlations which are missed by time-dependent Hartree-Fock approximation. The correlation energy of two-exciton can be probed with a very high resolution arising from a two-dimensional correlation spectrum, where two-exciton couplings spread the cross peaks along both axes of the 2D spectrum to create a characteristic highly resolved pattern. This level of detail is not available from conventional one-dimensional four-wave mixing or other two-dimensional correlation spectroscopy signals such as the photo echo (?k1+ k2+ k3). PMID:21785670

Yang, Lijun; Mukamel, Shaul

2011-01-01

242

Reconfigurable Computing for Digital Signal Processing: A Survey  

Microsoft Academic Search

Abstract. Steady advances in VLSI technology and design tools have extensively expanded,the application do- main of digital signal processing over the past decade. While application-specific integrated circuits (ASICs) and programmable,digital signal processors (PDSPs) remain the implementation,mechanisms,of choice for many,DSP applications, increasingly new system implementations based on reconfigurable computingare being considered. These flexible platforms, which offer the functional efficiency of hardware

Russell Tessier; Wayne Burleson

2001-01-01

243

Application of homomorphic signal processing to stress wave factor analysis  

NASA Technical Reports Server (NTRS)

The stress wave factor (SWF) signal, which is the output of an ultrasonic testing system where the transmitting and receiving transducers are coupled to the same face of the test structure, is analyzed in the frequency domain. The SWF signal generated in an isotropic elastic plate is modelled as the superposition of successive reflections. The reflection which is generated by the stress waves which travel P times as a longitudinal (P) wave and s times as a shear (S) wave through the plate while reflecting back and forth between the bottom and top faces of the plate is designated as the reflection with P, s. Short-time portions of the SWF signal are considered for obtaining spectral information on individual reflections. If the significant reflections are not overlapped, the short-time Fourier analysis is used. A summary of the elevant points of homomorphic signal processing, which is also called cepstrum analysis, is given. Homomorphic signal processing is applied to short-time SWF signals to obtain estimates of the log spectra of individual reflections for cases in which the reflections are overlapped. Two typical SWF signals generated in aluminum plates (overlapping and non-overlapping reflections) are analyzed.

Williams, J. H., Jr.; Lee, S. S.; Karaguelle, H.

1985-01-01

244

Application of homomorphic signal processing to stress wave factor analysis  

NASA Technical Reports Server (NTRS)

The stress wave factor (SWF) signal, which is the output of an ultrasonic testing system where the transmitting and receiving transducers are coupled to the same face of the test structure, is analyzed in the frequency domain. The SWF signal generated in an isotropic elastic plate is modelled as the superposition of successive reflections. The reflection which is generated by the stress waves which travel p times as a longitudinal (P) wave and s times as a shear (S) wave through the plate while reflecting back and forth between the bottom and top faces of the plate is designated as the reflection with p, s. Short-time portions of the SWF signal are considered for obtaining spectral information on individual reflections. If the significant reflections are not overlapped, the short-time Fourier analysis is used. A summary of the elevant points of homomorphic signal processing, which is also called cepstrum analysis, is given. Homomorphic signal processing is applied to short-time SWF signals to obtain estimates of the log spectra of individual reflections for cases in which the reflections are overlapped. Two typical SWF signals generated in aluminum plates (overlapping and non-overlapping reflections) are analyzed.

Karagulle, H.; Williams, J. H., Jr.; Lee, S. S.

1985-01-01

245

P-code enhanced method for processing encrypted GPS signals without knowledge of the encryption code  

NASA Technical Reports Server (NTRS)

In the preferred embodiment, an encrypted GPS signal is down-converted from RF to baseband to generate two quadrature components for each RF signal (L1 and L2). Separately and independently for each RF signal and each quadrature component, the four down-converted signals are counter-rotated with a respective model phase, correlated with a respective model P code, and then successively summed and dumped over presum intervals substantially coincident with chips of the respective encryption code. Without knowledge of the encryption-code signs, the effect of encryption-code sign flips is then substantially reduced by selected combinations of the resulting presums between associated quadrature components for each RF signal, separately and independently for the L1 and L2 signals. The resulting combined presums are then summed and dumped over longer intervals and further processed to extract amplitude, phase and delay for each RF signal. Precision of the resulting phase and delay values is approximately four times better than that obtained from straight cross-correlation of L1 and L2. This improved method provides the following options: separate and independent tracking of the L1-Y and L2-Y channels; separate and independent measurement of amplitude, phase and delay L1-Y channel; and removal of the half-cycle ambiguity in L1-Y and L2-Y carrier phase.

Meehan, Thomas K. (Inventor); Thomas, Jr., Jess Brooks (Inventor); Young, Lawrence E. (Inventor)

2000-01-01

246

The mathematical theory of signal processing and compression-designs  

NASA Astrophysics Data System (ADS)

The mathematical theory of signal processing, named processor coding, will be shown to inherently arise as the computational time dual of Shannon's mathematical theory of communication which is also known as source coding. Source coding is concerned with signal source memory space compression while processor coding deals with signal processor computational time compression. Their combination is named compression-designs and referred as Conde in short. A compelling and pedagogically appealing diagram will be discussed highlighting Conde's remarkable successful application to real-world knowledge-aided (KA) airborne moving target indicator (AMTI) radar.

Feria, Erlan H.

2006-05-01

247

Informatics and Mathematical Modelling / Intelligent Signal Processing Cognitive Component AnalysisCognitive Component Analysis  

E-print Network

Informatics and Mathematical Modelling / Intelligent Signal Processing Cognitive Component AnalysisCognitive / Intelligent Signal Processing OutlineOutline Introduction ofIntroduction of COgnitiveCOgnitive Component Informatics and Mathematical Modelling / Intelligent Signal Processing Cognitive Component AnalysisCognitive

248

Optical Signal Processing for High-speed Data Transmission  

NASA Astrophysics Data System (ADS)

The chapter describes high-speed optical data transmission based on optical time-division multiplexing (OTDM) with the focus on optical signal processing in the key building blocks of OTDM transmission systems. The OTDM transmitter is described including pulse generation, pulse shaping, and modulation of an optical pulse train. The OTDM receiver is discussed for direct detection and coherent detection systems. This includes signal processing using various optical gates, timing extraction devices, and optoelectronic base rate receivers, as well as the operation of phase-diversity homodyne receivers and coherent receivers as OTDM demultiplexers. A final section focuses on combating impairments in fiber links, i.e., using optical signal processing for the compensation of linear and higher order chromatic dispersion and polarization-mode dispersion as well.

Weber, Hans-Georg; Ludwig, Reinhold

249

Parallel Signal Processing and System Simulation using aCe  

NASA Technical Reports Server (NTRS)

Recently, networked and cluster computation have become very popular for both signal processing and system simulation. A new language is ideally suited for parallel signal processing applications and system simulation since it allows the programmer to explicitly express the computations that can be performed concurrently. In addition, the new C based parallel language (ace C) for architecture-adaptive programming allows programmers to implement algorithms and system simulation applications on parallel architectures by providing them with the assurance that future parallel architectures will be able to run their applications with a minimum of modification. In this paper, we will focus on some fundamental features of ace C and present a signal processing application (FFT).

Dorband, John E.; Aburdene, Maurice F.

2003-01-01

250

Detectors and signal processing for high-energy physics  

SciTech Connect

Basic principles of the particle detection and signal processing for high-energy physics experiments are presented. It is shown that the optimum performance of a properly designed detector system is not limited by incidental imperfections, but solely by more fundamental limitations imposed by the quantum nature and statistical behavior of matter. The noise sources connected with the detection and signal processing are studied. The concepts of optimal filtering and optimal detector/amplifying device matching are introduced. Signal processing for a liquid argon calorimeter is analyzed in some detail. The position detection in gas counters is studied. Resolution in drift chambers for the drift coordinate measurement as well as the second coordinate measurement is discussed.

Rehak, P.

1981-01-01

251

On-chip signal processing configurations for focal plane arrays  

NASA Astrophysics Data System (ADS)

Third generation FPAs are being designed to incorporate numerous sophisticated 'smart' functions, useful in the preprocessing and filtering of real-time image data. Designers at Nova Research, Inc. have developed ROIC designs which have increased the capabilities of these devices in the are of signal and image processing. These new FPAs are more versatile than their predecessors through the implementation of a variety of programmable modes of operation. This paper will discuss a variety of such processing functions and modes. Design configurations for such FPAs sill be discussed with regard to the incorporation of general and specific signal processing functions. Such functions will include but not be limited to: edge enhancement and edge extraction, accommodating high and low signal flux environments, high speed windowing and foveated pixel arrangements.

Baxter, Christopher R.; Massie, Mark A.

1999-07-01

252

Correlation-based pointwise processing of dynamic speckle patterns.  

PubMed

Correlation-based pointwise processing of dynamic speckle patterns is proposed for spatial characterization of activity in a sample. The result is a set of 2D activity maps of the estimates of temporal correlation, or structure functions, at increasing time lags. Pointwise computation provides spatial resolution, limited by the pixel period of the optical sensor used for acquisition of the speckle patterns. Pointwise normalization of the estimates solves the problem with the nonuniform illumination and varying reflectivity across the sample. The high contrast detailed activity maps obtained from processing of synthetic and experimental speckle patterns confirms efficiency of the proposed approach. PMID:24365836

Stoykova, Elena; Ivanov, Branimir; Nikova, Tania

2014-01-01

253

SEMICONDUCTOR TECHNOLOGY A signal processing method for the friction-based endpoint detection system of a CMP process  

NASA Astrophysics Data System (ADS)

A signal processing method for the friction-based endpoint detection system of a chemical mechanical polishing (CMP) process is presented. The signal process method uses the wavelet threshold denoising method to reduce the noise contained in the measured original signal, extracts the Kalman filter innovation from the denoised signal as the feature signal, and judges the CMP endpoint based on the feature of the Kalman filter innovation sequence during the CMP process. Applying the signal processing method, the endpoint detection experiments of the Cu CMP process were carried out. The results show that the signal processing method can judge the endpoint of the Cu CMP process.

Chi, Xu; Dongming, Guo; Zhuji, Jin; Renke, Kang

2010-12-01

254

Signal Processing For Chemical Sensing: Statistics or Biological Inspiration  

NASA Astrophysics Data System (ADS)

Current analytical instrumentation and continuous sensing can provide huge amounts of data. Automatic signal processing and information evaluation is needed to overcome drowning in data. Today, statistical techniques are typically used to analyse and extract information from continuous signals. However, it is very interesting to note that biology (insects and vertebrates) has found alternative solutions for chemical sensing and information processing. This is a brief introduction to the developments in the European Project: Bio-ICT NEUROCHEM: Biologically Inspired Computation for Chemical Sensing (grant no. 216916) Fp7 project devoted to biomimetic olfactory systems.

Marco, Santiago

2011-09-01

255

Non-linear canonical correlation for joint analysis of MEG signals from two subjects  

PubMed Central

Traditional stimulus-based analysis methods of magnetoencephalography (MEG) data are often dissatisfactory when applied to naturalistic experiments where two or more subjects are measured either simultaneously or sequentially. To uncover the commonalities in the brain activity of the two subjects, we propose a method that searches for linear transformations that output maximally correlated signals between the two brains. Our method is based on canonical correlation analysis (CCA), which provides linear transformations, one for each subject, such that the temporal correlation between the transformed MEG signals is maximized. Here, we present a non-linear version of CCA which measures the correlation of energies and allows for a variable delay between the time series to accommodate, e.g., leader–follower changes. We test the method with simulations and with MEG data from subjects who received the same naturalistic stimulus sequence. The method may help analyse future experiments where the two subjects are measured simultaneously while engaged in social interaction. PMID:23785311

Campi, Cristina; Parkkonen, Lauri; Hari, Riitta; Hyvärinen, Aapo

2013-01-01

256

Advanced study of video signal processing in low signal to noise environments  

NASA Technical Reports Server (NTRS)

The frame to frame correlation properties of the video process are utilized to reduce the mean squared error of the demodulated video where zero mean noise is a factor. An interpolative estimator is used for continuous estimation with the output process delayed in time by one frame. Theoretical development shows that for the model herein developed reduction of the mean squared error by 1.0 to 4.0 db possible for parameter ranges of interest. Interpolative estimation using inter-frame correlation properties of a video process is then applied to the Apollo 17 parameters to yield a model for application on that mission.

Carden, F.; Gilbert, A.

1972-01-01

257

Calcium Signals: The Lead Currency of Plant Information Processing  

PubMed Central

Ca2+ signals are core transducers and regulators in many adaptation and developmental processes of plants. Ca2+ signals are represented by stimulus-specific signatures that result from the concerted action of channels, pumps, and carriers that shape temporally and spatially defined Ca2+ elevations. Cellular Ca2+ signals are decoded and transmitted by a toolkit of Ca2+ binding proteins that relay this information into downstream responses. Major transduction routes of Ca2+ signaling involve Ca2+-regulated kinases mediating phosphorylation events that orchestrate downstream responses or comprise regulation of gene expression via Ca2+-regulated transcription factors and Ca2+-responsive promoter elements. Here, we review some of the remarkable progress that has been made in recent years, especially in identifying critical components functioning in Ca2+ signal transduction, both at the single-cell and multicellular level. Despite impressive progress in our understanding of the processing of Ca2+ signals during the past years, the elucidation of the exact mechanistic principles that underlie the specific recognition and conversion of the cellular Ca2+ currency into defined changes in protein–protein interaction, protein phosphorylation, and gene expression and thereby establish the specificity in stimulus response coupling remain to be explored. PMID:20354197

Kudla, Jörg; Batisti?, Oliver; Hashimoto, Kenji

2010-01-01

258

Signal Detection, Modularity, and the Correlation between Extrinsic and Intrinsic Noise in Biochemical Networks  

NASA Astrophysics Data System (ADS)

We present an expression for the power spectrum of the output signal of a biochemical network, which reveals that the reactions that allow a network to detect biochemical signals, induce correlations between the extrinsic noise of the input signals and the intrinsic noise of the reactions that form the network. We show that anticorrelations between the extrinsic and intrinsic noise enhance the robustness of zero-order ultrasensitive networks to biochemical noise. We discuss the consequences for a modular description of noise transmission using the mitogen-activated protein kinase cascade.

T?nase-Nicola, Sorin; Warren, Patrick B.; Ten Wolde, Pieter Rein

2006-08-01

259

Improved overlay metrology device correlation on 90-nm logic processes  

NASA Astrophysics Data System (ADS)

Isolated and dense patterns were formed at process layers from gate through to back-end on wafers using a 90 nm logic device process utilizing ArF lithography under various lithography conditions. Pattern placement errors (PPE) between AIM grating and BiB marks were characterized for line widths varying from 1000nm to 140nm. As pattern size was reduced, overlay discrepancies became larger, a tendency which was confirmed by optical simulation with simple coma aberration. Furthermore, incorporating such small patterns into conventional marks resulted in significant degradation in metrology performance while performance on small pattern segmented grating marks was excellent. Finally, the data also show good correlation between the grating mark and specialized design rule feature SEM marks, with poorer correlation between conventional mark and SEM mark confirming that new grating mark significantly improves overlay metrology correlation with device patterns.

Ueno, Atsushi; Tsujita, Kouichirou; Kurita, Hiroyuki; Iwata, Yasuhisa; Ghinovker, Mark; Poplawski, Jorge M.; Kassel, Elyakim; Adel, Mike E.

2004-05-01

260

Parallel-Processing Software for Correlating Stereo Images  

NASA Technical Reports Server (NTRS)

A computer program implements parallel- processing algorithms for cor relating images of terrain acquired by stereoscopic pairs of digital stereo cameras on an exploratory robotic vehicle (e.g., a Mars rove r). Such correlations are used to create three-dimensional computatio nal models of the terrain for navigation. In this program, the scene viewed by the cameras is segmented into subimages. Each subimage is assigned to one of a number of central processing units (CPUs) opera ting simultaneously.

Klimeck, Gerhard; Deen, Robert; Mcauley, Michael; DeJong, Eric

2007-01-01

261

Neural Correlates of Sublexical Processing in Phonological Working Memory  

ERIC Educational Resources Information Center

This study investigated links between working memory and speech processing systems. We used delayed pseudoword repetition in fMRI to investigate the neural correlates of sublexical structure in phonological working memory (pWM). We orthogonally varied the number of syllables and consonant clusters in auditory pseudowords and measured the neural…

McGettigan, Carolyn; Warren, Jane E.; Eisner, Frank; Marshall, Chloe R.; Shanmugalingam, Pradheep; Scott, Sophie K.

2011-01-01

262

The Analysis of Surface EMG Signals with the Wavelet-Based Correlation Dimension Method  

PubMed Central

Many attempts have been made to effectively improve a prosthetic system controlled by the classification of surface electromyographic (SEMG) signals. Recently, the development of methodologies to extract the effective features still remains a primary challenge. Previous studies have demonstrated that the SEMG signals have nonlinear characteristics. In this study, by combining the nonlinear time series analysis and the time-frequency domain methods, we proposed the wavelet-based correlation dimension method to extract the effective features of SEMG signals. The SEMG signals were firstly analyzed by the wavelet transform and the correlation dimension was calculated to obtain the features of the SEMG signals. Then, these features were used as the input vectors of a Gustafson-Kessel clustering classifier to discriminate four types of forearm movements. Our results showed that there are four separate clusters corresponding to different forearm movements at the third resolution level and the resulting classification accuracy was 100%, when two channels of SEMG signals were used. This indicates that the proposed approach can provide important insight into the nonlinear characteristics and the time-frequency domain features of SEMG signals and is suitable for classifying different types of forearm movements. By comparing with other existing methods, the proposed method exhibited more robustness and higher classification accuracy. PMID:24868240

Zhang, Yanyan; Wang, Jue

2014-01-01

263

Analysis of cross-correlations in electroencephalogram signals as an approach to proactive diagnosis of schizophrenia  

E-print Network

We apply flicker-noise spectroscopy (FNS), a time series analysis method operating on structure functions and power spectrum estimates, to study the clinical electroencephalogram (EEG) signals recorded in children/adolescents (11 to 14 years of age) with diagnosed schizophrenia-spectrum symptoms at the National Center for Psychiatric Health (NCPH) of the Russian Academy of Medical Sciences. The EEG signals for these subjects were compared with the signals for a control sample of chronically depressed children/adolescents. The purpose of the study is to look for diagnostic signs of subjects' susceptibility to schizophrenia in the FNS parameters for specific electrodes and cross-correlations between the signals simultaneously measured at different points on the scalp. Our analysis of EEG signals from scalp-mounted electrodes at locations F3 and F4, which are symmetrically positioned in the left and right frontal areas of cerebral cortex, respectively, demonstrates an essential role of frequency-phase synchroniz...

Timashev, Serge F; Polyakov, Yuriy S; Demin, Sergey A; Kaplan, Alexander Ya

2011-01-01

264

The detection and analysis of point processes in biological signals  

NASA Technical Reports Server (NTRS)

A pragmatic approach to the detection and analysis of discrete events in biomedical signals is taken. Examples from both clinical and basic research are provided. Introductory sections discuss not only discrete events which are easily extracted from recordings by conventional threshold detectors but also events embedded in other information carrying signals. The primary considerations are factors governing event-time resolution and the effects limits to this resolution have on the subsequent analysis of the underlying process. The analysis portion describes tests for qualifying the records as stationary point processes and procedures for providing meaningful information about the biological signals under investigation. All of these procedures are designed to be implemented on laboratory computers of modest computational capacity.

Anderson, D. J.; Correia, M. J.

1977-01-01

265

Monitoring Signaling Processes in Living Cells Using Biosensors  

NSDL National Science Digital Library

This collection of nine animations shows how different types of biosensors report changes in cellular processes through the production of a visually detectable signal. Biosensors can be created by attaching one or more fluorescent proteins (such as green fluorescent protein) to a target protein or peptide or by attaching a fluorescent dye that is sensitive to its environment to a protein or peptide. Conformational changes in proteins in response to ligand binding, changes in the concentration of cellular metabolites or signaling messengers, changes in protein localization, and changes in protein activity or covalent modification can all be detected with biosensors. These animations can be used separately or together to illustrate how molecular biology, chemistry, and microscopy have converged to allow cellular processes to be visualized in living cells. Several of the animations describe the production of a fluorescent resonance energy transfer (FRET) signal.

Klaus Hahn (Scripps Research Institute; Department of Cell Biology; REV)

2003-10-21

266

Abstract--Genomic Signal Processing is a new area of research that combines advanced digital signal processing methodologies for enhanced genetic data analysis.  

E-print Network

1 Abstract-- Genomic Signal Processing is a new area of research that combines advanced digital accuracy compared to other digital signal processing and well known statistical methods. Index Terms advanced digital signal processing methodologies for genetic data processing and visualization [3

Nebel, Jean-Christophe

267

Parallel Processing of Broad-Band PPM Signals  

NASA Technical Reports Server (NTRS)

A parallel-processing algorithm and a hardware architecture to implement the algorithm have been devised for timeslot synchronization in the reception of pulse-position-modulated (PPM) optical or radio signals. As in the cases of some prior algorithms and architectures for parallel, discrete-time, digital processing of signals other than PPM, an incoming broadband signal is divided into multiple parallel narrower-band signals by means of sub-sampling and filtering. The number of parallel streams is chosen so that the frequency content of the narrower-band signals is low enough to enable processing by relatively-low speed complementary metal oxide semiconductor (CMOS) electronic circuitry. The algorithm and architecture are intended to satisfy requirements for time-varying time-slot synchronization and post-detection filtering, with correction of timing errors independent of estimation of timing errors. They are also intended to afford flexibility for dynamic reconfiguration and upgrading. The architecture is implemented in a reconfigurable CMOS processor in the form of a field-programmable gate array. The algorithm and its hardware implementation incorporate three separate time-varying filter banks for three distinct functions: correction of sub-sample timing errors, post-detection filtering, and post-detection estimation of timing errors. The design of the filter bank for correction of timing errors, the method of estimating timing errors, and the design of a feedback-loop filter are governed by a host of parameters, the most critical one, with regard to processing very broadband signals with CMOS hardware, being the number of parallel streams (equivalently, the rate-reduction parameter).

Gray, Andrew; Kang, Edward; Lay, Norman; Vilnrotter, Victor; Srinivasan, Meera; Lee, Clement

2010-01-01

268

Signal processing techniques for surveillance radar - An overview  

Microsoft Academic Search

The present paper is concerned with a survey of the signal processing techniques presently employed in modern air defense and surveillance radars and those techniques likely to be applied in the future. Attention is given to the requirements for enhancing performance in surveillance radar, current processing techniques, advanced techniques, low probability of intercept (LPI) and anti-ARM (anti-radiation missile), anti-stealth, digital

A. Farina; G. Galati

1985-01-01

269

Finn Arup Nielsen Section for Digital Signal Processing  

E-print Network

VRML Finn Å¡ Arup Nielsen Section for Digital Signal Processing Department of Mathematical Modelling: eivind.imm.dtu.dk WWW: http://eivind.imm.dtu.dk #12; Finn Å¡ Arup Nielsen, DSP, IMM, DTU January 7, 1997 animation \\Psi Internet enabled ffl 2 #12; Finn Å¡ Arup Nielsen, DSP, IMM, DTU January 7, 1997 ... VRML

Nielsen, Finn Ã?rup

270

Introduction to Digital Signal Processing ENG EC416 (Spring 2013)  

E-print Network

and music (1-D), and images (2-D). #12;2) Understand the time- and frequency-domain concepts related to A of this course is to introduce basic concepts and methods of digital signal processing (DSP), i.e., digital), consumer electronics (CD, MP3 players, digital cameras), entertainment (DV, DVD, BluRay, HDTV, digital

271

Time delay estimation for passive sonar signal processing  

Microsoft Academic Search

An overview of applied research in passive sonar signal processing estimation techniques for naval systems is presented. The naval problem that motivates time delay estimation is the source state estimation problem. A discussion of this problem in terms of estimating the position and velocity of a moving acoustic source is presented. Optimum bearing and range estimators are presented for the

G. Carter

1981-01-01

272

Signal processing for the TOPAZ Time Projection Chamber  

SciTech Connect

The signals from the TOPAZ Time Projection Chamber, after being processed by a low noise preamplifier and a shaper amplifier, are recorded by a CCD based digitizer system. The system achieved an integral operation in the environment of FASTBUS with Sector Sequencers and FPI.

Ikeda, H.; Iwasaki, H.; Iwata, S.; Kobayashi, M.; Matsuda, T.; Nakamura, K.; Yamauchi, M.; Aihara, H.; Enomoto, R.; Fujii, H.

1987-02-01

273

An Interactive Graphics Program for Investigating Digital Signal Processing.  

ERIC Educational Resources Information Center

Describes development of an interactive computer graphics program for use in teaching digital signal processing. The program allows students to interactively configure digital systems on a monitor display and observe their system's performance by means of digital plots on the system's outputs. A sample program run is included. (JN)

Miller, Billy K.; And Others

1983-01-01

274

CORDIC-based VLSI architectures for digital signal processing  

Microsoft Academic Search

The evolution of CORDIC, an iterative arithmetic computing algorithm capable of evaluating various elementary functions using a unified shift-and-add approach, and of CORDIC processors is reviewed. A method to utilize a CORDIC processor array to implement digital signal processing algorithms is presented. The approach is to reformulate existing DSP algorithms so that they are suitable for implementation with an array

Y. H. Hu

1992-01-01

275

Automatic image stabilizing system by full-digital signal processing  

Microsoft Academic Search

An automatic image-stabilizing system for camcorders and VCRs utilizing only digital signal processing has been developed. New technologies for this system are (1) the BERP (band extract representative point) matching technique with a small-scale circuit, (2) an adaptive system control algorithm to discriminate moving objects, and (3) suppression of motion vectors due to noise. Calculations show that the motion vector

K. Uomori; A. Morimura; H. Ishii; T. Sakaguchi; Y. Kitamura

1990-01-01

276

A new signal processing platform for radio astronomy  

Microsoft Academic Search

Context: We describe the concept, construction, and testing of TasPGA, a new, versatile digital signal processing device designed for radio astronomy applications. Aims: A minimalist design philosophy was used to develop a general-purpose radio astronomy instrument based on field programmable gate array (FPGA) technology. The design emphasises reliability and flexibility, facilitating the rapid development of new FPGA firmware for a

A. W. Hotan

2008-01-01

277

Informatics and Mathematical Modelling / Intelligent Signal Processing 1Jan Larsen  

E-print Network

Informatics and Mathematical Modelling / Intelligent Signal Processing 1Jan Larsen LSA ­ Algorithms Ph.D.-student Lasse Lohilahti Mølgaard #12;Informatics and Mathematical Modelling / Intelligent interpretation ­ Results in retrieval Demos ­ Castsearch ­ Wikipedia #12;Informatics and Mathematical Modelling

278

SPLINES : A PERFECT FIT FOR SIGNAL\\/IMAGE PROCESSING  

Microsoft Academic Search

This paper attempts to fullfill three goals. The first one is to provide a tutorial on splinesthat is geared to a signal processing audience. The second one is to gather all their importantproperties, and to provide an overview of the mathematical and computational tools available;i.e., a road map for the practitioner with references to the appropriate literature. The third goalis

Michael Unser

1999-01-01

279

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing  

E-print Network

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Laboratory, Department of Mechatronics, Gwangju Institute of Science and Technology (GIST), 1 Oryong devel- oped. Most linear methods are based on the regularization (see [1, 2]) while nonlinear methods

Masci, Frank

280

Forensically Determining the Order of Signal Processing Operations  

E-print Network

manipulated a signal. In this paper, we propose a new forensic detection framework that can be used determine applied to an image. I. INTRODUCTION In today's society, the majority of multimedia content is captured to identify the use of specific image processing operations and manipulations. These forensic techniques work

Liu, K. J. Ray

281

Signal processing in medical imaging and image-guided intervention  

Microsoft Academic Search

Thisis an introductionto a specialsession ofICASSP devoted to signalprocessing techniquesin medicalimagingand image analysis that consists of this introduction and 5 research presentations, each addressingone aspect of the medicalimaging field in which signal processing plays an irreplaceable role. The topics cover a broad spectrum of medical imaging problems from image acquisition to image analysis to populationbased anatomical modeling. The focus is

Milan Sonka

2011-01-01

282

Diffraction tomographic signal processing algorithms for tunnel detection  

Microsoft Academic Search

Signal processing algorithms have been developed for wave based imaging using diffraction tomography. The basis for this image reconstruction procedure is the generalized projection slice theorem (GPST) which, for homogeneous waves, is an analytic relationship between the spatial Fourier transform of the acquired data and the spatial Fourier transform of the spatial profile (object function) of the object being imaged.

1993-01-01

283

Metamaterials for threat reduction applications: imaging, signal processing, and cloaking  

E-print Network

Metamaterials for threat reduction applications: imaging, signal processing, and cloaking R. D structured materials, termed metamaterials (MM), has dramati- cally expanded our view of electromagnetic with metamaterials provides a promising approach--from a device perspective--towards fill- ing this gap

284

VOLUME 7, ISSUE 3 JULY 2011 Signal Processing in Acoustics  

E-print Network

VOLUME 7, ISSUE 3 JULY 2011 Signal Processing in Acoustics Acoustics Today A publication of the Acoustical Society of America Model-Based Ocean Acoustics Physical and Engineering Acoustics Speech have been applied to data with biological origins: ­ "Three-dimensional passive acoustic localization

Jaffe, Jules

285

[president's message] IEEE SIGNAL PROCESSING MAGAZINE [4] MARCh 2013  

E-print Network

the prestige of an award. The IEEE Signal Processing Society (SPS) bylaws and policies clearly lay out the BOG votes and selects the winners. It is also stated that a member of the Awards Board is not eligible influence is not removable for someone in a position to influence! So the best that we can do is to avoid

Liu, K. J. Ray

286

Cancer systems biology: signal processing for cancer research  

PubMed Central

In this editorial we introduce the research paradigms of signal processing in the era of systems biology. Signal processing is a field of science traditionally focused on modeling electronic and communications systems, but recently it has turned to biological applications with astounding results. The essence of signal processing is to describe the natural world by mathematical models and then, based on these models, develop efficient computational tools for solving engineering problems. Here, we underline, with examples, the endless possibilities which arise when the battle-hardened tools of engineering are applied to solve the problems that have tormented cancer researchers. Based on this approach, a new field has emerged, called cancer systems biology. Despite its short history, cancer systems biology has already produced several success stories tackling previously impracticable problems. Perhaps most importantly, it has been accepted as an integral part of the major endeavors of cancer research, such as analyzing the genomic and epigenomic data produced by The Cancer Genome Atlas (TCGA) project. Finally, we show that signal processing and cancer research, two fields that are seemingly distant from each other, have merged into a field that is indeed more than the sum of its parts. PMID:21439242

Yli-Harja, Olli; Ylipää, Antti; Nykter, Matti; Zhang, Wei

2011-01-01

287

Signal processing underlying extrinsic control of stem cell fate  

E-print Network

Signal processing underlying extrinsic control of stem cell fate Ryan E. Davey and Peter W. Zandstra Purpose of review Strategies to manipulate stem cells for therapeutic applications are limited by our inability to control or predict stem cell fate decisions in response to exogenous stimuli

Zandstra, Peter W.

288

Signal processing tools for geoacoustic inversion in shallow water  

E-print Network

In shallow water, for low frequency source, the most suitable propagation model is the normal mode theory [1Signal processing tools for geoacoustic inversion in shallow water Julien Bonnel GIPSA-Lab / DIS Abstract-- Low frequency propagation in shallow water is described by modal theory. One challenge has been

Boyer, Edmond

289

Signal Processing for Phased Array Feeds in Radio Astronomical Telescopes  

E-print Network

@ee.byu.edu), except : National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903-2475, rfisher the earliest days of radio astronomy (RA), detecting faint deep space sources has pushed available technologySignal Processing for Phased Array Feeds in Radio Astronomical Telescopes Brian D. Jeffs, Senior

Wirthlin, Michael J.

290

Signal processing techniques for clutter filtering and wind shear detection  

NASA Technical Reports Server (NTRS)

An extended Prony algorithm applicable to signal processing techniques for clutter filtering and windshear detection is discussed. The algorithm is based upon modelling the radar return as a time series, and appears to offer potential for improving hazard factor estimates in the presence of strong clutter returns.

Baxa, Ernest G., Jr.; Deshpande, Manohar D

1991-01-01

291

Nonlinear fibers for signal processing using optical Kerr effects  

Microsoft Academic Search

This paper reviews nonlinear optical-fiber designs for signal processing using optical Kerr effects. The requirements for designing nonlinear fibers are described first. Then, the design concept is discussed and design examples are shown to illustrate the tradeoffs among the different fiber properties such as effective area, dispersion, and attenuation. Furthermore, fiber designs with distributed Brillouin frequency shift to mitigate the

Ming-Jun Li; Shenping Li; Daniel A. Nolan

2005-01-01

292

CCITT Activity on signal processing for integrated services digital networks  

Microsoft Academic Search

This paper gives a snapshot of the international activity on standards to be set for speech, sound and picture signals processing for application in the emerging Integrated Services Digital Networks (ISDN). The ISDN is a focal point for the ongoing activity of the CCITT (International Telegraph and Telephone Consultative Committee). ISDNs are conceived as networks which have evolved from the

M. Decina

1982-01-01

293

Parallel architectures for processing high speed network signaling protocols  

Microsoft Academic Search

A6sfract-We study the effectiveness of different parallel arcbitecturea for achieving the high throughput and low Iatenciea needed in processing signaling protocols for I@ speed networks. A key performance issue is the trade off between the load batancing gains and the call record management overhead. Arranging processors in targe groups potentially yields higher load balancing gains but also incurs higher overhead

Dipak Ghosal; T. V. Lakshman; Yennun Huang

1995-01-01

294

Singular value decomposition with normalized period for magnetocaridiography signal processing  

NASA Astrophysics Data System (ADS)

In this paper, we have developed an algorithm based on singular value decomposition (SVD) for matrix. And the novel SVD algorithm with normalized period of cardiac cycles is presented. The results from real magnetocardiography (MCG) data processing show that the new algorithm is better than the standard one not only in suppressing noises, but also in providing high-fidelity MCG signals.

Li, Zhuo; Liu, Dang-Ting; Tian, Ye; Chen, Geng-Hua; Zhang, Li-Hua; Yang, Qian-Sheng; Feng, Ji

2007-10-01

295

Applets for Chromatography, Signal Processing and General Analytical Chemistry  

NSDL National Science Digital Library

This site offers Java-based applets as organized in 4 categories: analytical and general chemistry, instrumental chemical analysis, instrumentation/signal processing, data analysis/chemometrics. Each applet includes a short introduction followed by a user controlled input of experimental conditions, such as seen for diffusion in electrochemistry.

296

Adventures in Radio Astronomy Instrumentation and Signal Processing  

E-print Network

using radio telescopes. Modern radio telescopes have significant digital signal processing demands of spectrometers for enabling improved pulsar2 sci- ence on the Allen Telescope Array, the Hartebeesthoek Radio Observatory telescope, the Nan¸cay Radio Telescope, and the Parkes Radio Telescope. We also present work

Masci, Frank

297

Adventures in Radio Astronomy Instrumentation and Signal Processing  

E-print Network

- tizing and processing analogue astronomical signals collected using radio telescopes. Modern radio pulsar2 sci- ence on the Allen Telescope Array, the Hartebeesthoek Radio Observatory telescope, the Nan¸cay Radio Telescope, and the Parkes Radio Telescope. We also present work that we conducted

California at Berkeley, University of

298

H. C. So Page 1 Semester B, 2011-2012 Overview of Digital Signal Processing (DSP)  

E-print Network

H. C. So Page 1 Semester B, 2011-2012 Overview of Digital Signal Processing (DSP) Signal: Anything-2012 quantized signal digital signal processor sample at analog signal sampled signal t amplitude t amplitude 0 0 = digital signal, or the quantizer has infinite resolution #12;H. C. So Page 9 Semester B, 2011-2012 System

So, Hing-Cheung

299

Activation of Parallel Fiber Feedback by Spatially Diffuse Stimuli Reduces Signal and Noise Correlations via Independent Mechanisms in a Cerebellum-Like Structure  

PubMed Central

Correlations between the activities of neighboring neurons are observed ubiquitously across systems and species and are dynamically regulated by several factors such as the stimulus' spatiotemporal extent as well as by the brain's internal state. Using the electrosensory system of gymnotiform weakly electric fish, we recorded the activities of pyramidal cell pairs within the electrosensory lateral line lobe (ELL) under spatially localized and diffuse stimulation. We found that both signal and noise correlations were markedly reduced (>40%) under the latter stimulation. Through a network model incorporating key anatomical features of the ELL, we reveal how activation of diffuse parallel fiber feedback from granule cells by spatially diffuse stimulation can explain both the reduction in signal as well as the reduction in noise correlations seen experimentally through independent mechanisms. First, we show that burst-timing dependent plasticity, which leads to a negative image of the stimulus and thereby reduces single neuron responses, decreases signal but not noise correlations. Second, we show trial-to-trial variability in the responses of single granule cells to sensory input reduces noise but not signal correlations. Thus, our model predicts that the same feedback pathway can simultaneously reduce both signal and noise correlations through independent mechanisms. To test this prediction experimentally, we pharmacologically inactivated parallel fiber feedback onto ELL pyramidal cells. In agreement with modeling predictions, we found that inactivation increased both signal and noise correlations but that there was no significant relationship between magnitude of the increase in signal correlations and the magnitude of the increase in noise correlations. The mechanisms reported in this study are expected to be generally applicable to the cerebellum as well as other cerebellum-like structures. We further discuss the implications of such decorrelation on the neural coding strategies used by the electrosensory and by other systems to process natural stimuli. PMID:25569283

Simmonds, Benjamin; Chacron, Maurice J.

2015-01-01

300

Biomechanical Correlates of Surface Electromyography Signals Obtained during Swallowing by Healthy Adults  

ERIC Educational Resources Information Center

Purpose: The purpose of this study was to describe biomechanical correlates of the surface electromyographic signal obtained during swallowing by healthy adult volunteers. Method: Seventeen healthy adults were evaluated with simultaneous videofluoroscopy and surface electromyography (sEMG) while swallowing 5 mL of liquid barium sulfate. Three…

Crary, Michael A.; Carnaby (Mann), Giselle D.; Groher, Michael E.

2006-01-01

301

Periodic-orbit determination of dynamical correlations in stochastic processes  

E-print Network

It is shown that large deviation statistical quantities of the discrete time, finite state Markov process $P_{n+1}^{(j)}=\\sum_{k=1}^NH_{jk}P_n^{(k)}$, where P_n^{(j)} is the probability for the j-state at the time step n and H_{jk} is the transition probability, completely coincides with those from the Kalman map corresponding to the above Markov process. Furthermore, it is demonstrated that by using simple examples, time correlation functions in finite state Markov processes can be well described in terms of unstable periodic orbits embedded in the equivalent Kalman maps.

Miki U. Kobayashi; Hirokazu Fujisaka; Syuji Miyazaki

2007-08-10

302

Signal Assignment Model for the Memory Management of Multidimensional Signal Processing Applications  

Microsoft Academic Search

Many signal processing systems, particularly in the multimedia and telecom domains, are synthe- sized to execute data-dominated applications. Their behavior is described in a high-level programming lan- guage, where the code is typically organized in se- quences of loop nests and the main data structures are multidimensional arrays. Since data transfer and storage have a significant impact on both the

Florin Balasa; Ilie I. Luican; Hongwei Zhu; Doru V. Nasui

2011-01-01

303

Limitations of signal averaging due to temporal correlation in laser remote-sensing measurements  

NASA Technical Reports Server (NTRS)

Laser remote sensing involves the measurement of laser-beam transmission through the atmosphere and is subject to uncertainties caused by strong fluctuations due primarily to speckle, glint, and atmospheric-turbulence effects. These uncertainties are generally reduced by taking average values of increasing numbers of measurements. An experiment was carried out to directly measure the effect of signal averaging on back-scattered laser return signals from a diffusely reflecting target using a direct-detection differential-absorption lidar (DIAL) system. The improvement in accuracy obtained by averaging over increasing numbers of data points was found to be smaller than that predicted for independent measurements. The experimental results are shown to be in excellent agreement with a theoretical analysis which considers the effect of temporal correlation. The analysis indicates that small but long-term temporal correlation severely limits the improvement available through signal averaging.

Menyuk, N.; Killinger, D. K.; Menyuk, C. R.

1982-01-01

304

Method and apparatus for a single channel digital communications system. [synchronization of received PCM signal by digital correlation with reference signal  

NASA Technical Reports Server (NTRS)

A method and apparatus are described for synchronizing a received PCM communications signal without requiring a separate synchronizing channel. The technique provides digital correlation of the received signal with a reference signal, first with its unmodulated subcarrier and then with a bit sync code modulated subcarrier, where the code sequence length is equal in duration to each data bit.

Couvillon, L. A., Jr.; Carl, C.; Goldstein, R. M.; Posner, E. C.; Green, R. R. (inventors)

1973-01-01

305

Information retrieval and cross-correlation function analysis of random noise radar signal through dispersive media  

NASA Astrophysics Data System (ADS)

In this contribution we examine the propagation of an ultrawideband (UWB) random noise signal through dispersive media such as soil, vegetation, and water, using Fourier-based analysis. For such media, the propagated signal undergoes medium-specific impairments which degrade the received signal in a different way than the non-dispersive propagation media. Theoretically, larger penetration depths into a dispersive medium can be achieved by identifying and detecting the precursors, thereby offering significantly better signal-to-noise ratio and enhanced imaging. For a random noise signal, well defined precursors in term of peak-amplitude don't occur. The phenomenon must therefore be studied in terms of energy evolution. Additionally, the distortion undergone by the UWB random noise signal through a dispersive medium can introduce frequency-dependent uncertainty or noise in the received signal. This leads to larger degradation of the cross-correlation function (CCF), mainly in terms of sidelobe levels and main peak deformation, and consequently making the information retrieval difficult. We would further analyze one method to restore the shape and carrier frequency of the input UWB random noise signal, thereby, improving the CCF estimation.

Alejos, Ana Vazques; Dawood, Muhammad

2012-06-01

306

Mass Spectral Peak Distortion Due to Fourier Transform Signal Processing  

NASA Astrophysics Data System (ADS)

Distortions of peaks can occur when one uses the standard method of signal processing of data from the Orbitrap and other FT-based methods of mass spectrometry. These distortions arise because the standard method of signal processing is not a linear process. If one adds two or more functions, such as time-dependent signals from a Fourier transform mass spectrometer and performs a linear operation on the sum, the result is the same as if the operation was performed on separate functions and the results added. If this relationship is not valid, the operation is non-linear and can produce unexpected and/or distorted results. Although the Fourier transform itself is a linear operator, the standard algorithm for processing spectra in Fourier transform-based methods include non-linear mathematical operators such that spectra processed by the standard algorithm may become distorted. The most serious consequence is that apparent abundances of the peaks in the spectrum may be incorrect. In light of these considerations, we performed theoretical modeling studies to illustrate several distortion effects that can be observed, including abundance distortions. In addition, we discuss experimental systems where these effects may manifest, including suggested systems for study that should demonstrate these peak distortions. Finally, we point to several examples in the literature where peak distortions may be rationalized by the phenomena presented here.

Rockwood, Alan L.; Erve, John C. L.

2014-12-01

307

A digital signal processing system for coherent laser radar  

NASA Technical Reports Server (NTRS)

A data processing system for use with continuous-wave lidar is described in terms of its configuration and performance during the second survey mission of NASA'a Global Backscatter Experiment. The system is designed to estimate a complete lidar spectrum in real time, record the data from two lidars, and monitor variables related to the lidar operating environment. The PC-based system includes a transient capture board, a digital-signal processing (DSP) board, and a low-speed data-acquisition board. Both unprocessed and processed lidar spectrum data are monitored in real time, and the results are compared to those of a previous non-DSP-based system. Because the DSP-based system is digital it is slower than the surface-acoustic-wave signal processor and collects 2500 spectra/s. However, the DSP-based system provides complete data sets at two wavelengths from the continuous-wave lidars.

Hampton, Diana M.; Jones, William D.; Rothermel, Jeffry

1991-01-01

308

Snore related signals processing in a private cloud computing system.  

PubMed

Snore related signals (SRS) have been demonstrated to carry important information about the obstruction site and degree in the upper airway of Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) patients in recent years. To make this acoustic signal analysis method more accurate and robust, big SRS data processing is inevitable. As an emerging concept and technology, cloud computing has motivated numerous researchers and engineers to exploit applications both in academic and industry field, which could have an ability to implement a huge blue print in biomedical engineering. Considering the security and transferring requirement of biomedical data, we designed a system based on private cloud computing to process SRS. Then we set the comparable experiments of processing a 5-hour audio recording of an OSAHS patient by a personal computer, a server and a private cloud computing system to demonstrate the efficiency of the infrastructure we proposed. PMID:25205499

Qian, Kun; Guo, Jian; Xu, Huijie; Zhu, Zhaomeng; Zhang, Gongxuan

2014-09-01

309

A novel optoelectronic oscillator based on all optical signal processing  

NASA Astrophysics Data System (ADS)

A novel dual-loop optoelectronic oscillator (OEO), which is constructed based on all optical signal processing, is proposed and analyzed. By inserting an erbium-doped fiber amplifier (EDFA) and a fiber Bragg grating (FBG) on the optical domain, the amplification and filter are implemented in the OEO loop. The performance of the OEO is improved without any electronic filter or electronic amplifier. A theoretical analysis is performed, and the generated microwave signal exhibits good performance with phase noise lower than -120 dBc/Hz at 10 kHz and a high side-mode suppression ratio (SMSR).

Li, Cheng-xin; Chen, Fu-shen; Zhang, Jia-hong; Mao, Jiu-bing

2013-09-01

310

The Scientist and Engineer's Guide to Digital Signal Processing  

NSDL National Science Digital Library

Dr. Steve Smith offers his book about digital signal processing (DSP) free, in its entirety, on this site. The DSP guide introduces the reader to the fundamentals, and then delves into digital filters, applications, and complex techniques. All 33 chapters can be downloaded individually or as a whole. The book is quite well written, with plenty of figures, graphs, and illustrations that accompany the text. Smith derives equations for topics such as Fourier and Laplace transforms, and he clearly defines the terms and how to use them. This book is excellent for college students in a DSP or signals communications course.

Smith, Steven W.

2002-01-01

311

Exploiting the Analogy Between Traces and Signal Processing  

Microsoft Academic Search

The main challenge of dynamic analysis is the huge\\u000a volume of data, making it difficult to extract high\\u000a level views. Most techniques developed so far adopt\\u000a a fine-grained approach to address this issue. In\\u000a this paper we introduce a novel approach\\u000a representing entire traces as signals in time.\\u000a Drawing this analogy between dynamic analysis and\\u000a signal processing, we are able

Adrian Kuhn; Orla Greevy

2006-01-01

312

The high speed low noise multi-data processing signal process circuit research of remote sensing  

NASA Astrophysics Data System (ADS)

The high speed, low noise and integration characteristic are the main technology and the main development directions on the signal process circuit of the image sensor, especially in high resolution remote sensing. With these developments, the high noise limiting circuits, high speed data transfer system and the integrated design of the signal process circuit become more and more important. Therefore the requirement of the circuit system simulation is more and more important during the system design and PCB board design process. A CCD signal process circuit system which has the high speed, low noise and several selectable operate modes function was designed and certificated in this paper, during the CCD signal process circuit system design, simulation was made which include the signal integrity and the power integrity. The important devices such as FPGA and the DDR2 device were simulated, using the power integrity simulation the sensitive power planes of the FPGA on the PCB was modified to make the circuit operate more stabilize on a higher frequency. The main clock path and the high speed data path of the PCB board were simulated with the signal integrity. All the simulation works make the signal process circuit system's image's SNR value get higher and make the circuit system could operate well on higher frequency. In the board testing process, the PCB time diagrams were listed on the testing chapter and the wave's parameter meets the request. The real time diagram and the simulated result of the PCB board was listed respectively. The CCD signal process circuit system's images' SNR (Signal Noise Ratio) value, the 14bit AFE slew rate and the data transfer frequency is listed in the paper respective.

Su, Lei; Jiang, Haibin; Dong, Wang

2013-08-01

313

Two-point correlation properties of stochastic splitting processes  

NASA Astrophysics Data System (ADS)

We study how the two-point density correlation properties of a point particle distribution are modified when each particle is divided, by a stochastic process, into an equal number of identical “daughter” particles. We consider generically that there may be nontrivial correlations in the displacement fields describing the positions of the different daughters of the same “mother” particle and then treat separately the cases in which there are, or are not, correlations also between the displacements of daughters belonging to different mothers. For both cases exact formulas are derived relating the structure factor (power spectrum) of the daughter distribution to that of the mothers. An application of these results is that they give explicit algorithms for generating, starting from regular lattice arrays, stochastic particle distributions with an arbitrarily high degree of large-scale uniformity. Such distributions are of interest, in particular, in the context of studies of self-gravitating systems in cosmology.

Gabrielli, Andrea; Joyce, Michael

2008-03-01

314

Tracking the dehydration process of raw honey by synchronous two-dimensional near infrared correlation spectroscopy  

NASA Astrophysics Data System (ADS)

Though much attention is paid to honey quality assessment, few reports on characteristic of manually dehydrated honey have been found. The aim of this investigation is to track the dehydration process of raw honey using synchronous two-dimensional (2D) near infrared correlation spectroscopy. To minimize the impact of dehydration to honey quality, seventy-two honey samples from six different dehydration stages were obtained using drum wind drying method with temperature controlled at 40 °C. Their dynamic short-wave NIR spectra from 600 to 1100 nm were collected in the transmission mode from 10 to 50 °C with an increment of 5 °C and were analyzed using synchronous two-dimensional correlation method. Short-wave NIR spectral data has been exploited less than other NIR region for its weaker signal especially for water absorption's interference with useful information. The investigation enlarged the signal at this band using synchronous 2D correlation analysis, revealing the fingerprinting feature of rape honey and chaste honey during the artificial dehydration process. The results have shown that, with the help of 2D correlation analysis, this band can detect the variation of the second overtone of O-H and N-H groups vibration upon their H-bonds forming or collapsing resulted from the interactions between water and solute. The results have also shown that 2D-NIRS method is able to convert the tiny changes in honey constituents into the detectable fingerprinting difference, which provides a new method for assessing honey quality.

Chen, Guiyun; Sun, Xin; Huang, Yuping; Chen, Kunjie

2014-11-01

315

EE 362.3 (3L-3P alt. weeks) Digital Signal Processing  

E-print Network

EE 362.3 (3L-3P alt. weeks) Digital Signal Processing Department of Electrical and Computer-Time and Continuous-Time Signals, Sampling Rate Change, Multirate Signal Processing, Digital Processing of Analog Engineering Fall 2014 Description: This course covers the basic theory of discrete-time signal processing

Saskatchewan, University of

316

Synthetic aperture radar signal processing on the MPP  

NASA Technical Reports Server (NTRS)

Satellite-borne Synthetic Aperture Radars (SAR) sense areas of several thousand square kilometers in seconds and transmit phase history signal data several tens of megabits per second. The Shuttle Imaging Radar-B (SIR-B) has a variable swath of 20 to 50 km and acquired data over 100 kms along track in about 13 seconds. With the simplification of separability of the reference function, the processing still requires considerable resources; high speed I/O, large memory and fast computation. Processing systems with regular hardware take hours to process one Seasat image and about one hour for a SIR-B image. Bringing this processing time closer to acquisition times requires an end-to-end system solution. For the purpose of demonstration, software was implemented on the present Massively Parallel Processor (MPP) configuration for processing Seasat and SIR-B data. The software takes advantage of the high processing speed offered by the MPP, the large Staging Buffer, and the high speed I/O between the MPP array unit and the Staging Buffer. It was found that with unoptimized Parallel Pascal code, the processing time on the MPP for a 4096 x 4096 sample subset of signal data ranges between 18 and 30.2 seconds depending on options.

Ramapriyan, H. K.; Seiler, E. J.

1987-01-01

317

DIGITAL SIGNAL PROCESSING--FALL 2013 This course provides a comprehensive introduction to the use of Fourier methods in digital signal processing.  

E-print Network

DIGITAL SIGNAL PROCESSING--FALL 2013 This course provides a comprehensive introduction to the use of Fourier methods in digital signal processing. COURSE INFORMATION Instructor: Jim Walker Office: 527 signals. There is a follow-up course, Digital Image Processing (Math/Phys 440), which treats frequencies

Walker, James S.

318

Currently, there is a substantial research and development effort directed toward optical signal processing and electronic signal processing for fiber-optic communications. Much of the work  

E-print Network

signal processing and electronic signal processing for fiber-optic communications. Much of the work fiber-optic transmitters and receivers, and has lead to a renewed interest in coherent optical detection and Electronic Signal Processing for Fiber-Optic Communications IEEE Photonics Societ y Distinguished Lecture B y

Wu, Shin-Tson

319

Fast computation of local correlation coefficients on graphics processing units  

NASA Astrophysics Data System (ADS)

This paper presents an acceleration method, using both algorithmic and architectural means, for fast calculation of local correlation coefficients, which is a basic image-based information processing step for template or pattern matching, image registration, motion or change detection and estimation, compensation of changes, or compression of representations, among other information processing objectives. For real-time applications, the complexity in arithmetic operations as well as in programming and memory access latency had been a divisive issue between the so-called correction-based methods and the Fourier domain methods. In the presented method, the complexity in calculating local correlation coefficients is reduced via equivalent reformulation that leads to efficient array operations or enables the use of multi-dimensional fast Fourier transforms, without losing or sacrificing local and non-linear changes or characteristics.

Papamakarios, Georgios; Rizos, Georgios; Pitsianis, Nikos P.; Sun, Xiaobai

2009-08-01

320

Digital signal processing algorithms for automatic voice recognition  

NASA Technical Reports Server (NTRS)

The current digital signal analysis algorithms are investigated that are implemented in automatic voice recognition algorithms. Automatic voice recognition means, the capability of a computer to recognize and interact with verbal commands. The digital signal is focused on, rather than the linguistic, analysis of speech signal. Several digital signal processing algorithms are available for voice recognition. Some of these algorithms are: Linear Predictive Coding (LPC), Short-time Fourier Analysis, and Cepstrum Analysis. Among these algorithms, the LPC is the most widely used. This algorithm has short execution time and do not require large memory storage. However, it has several limitations due to the assumptions used to develop it. The other 2 algorithms are frequency domain algorithms with not many assumptions, but they are not widely implemented or investigated. However, with the recent advances in the digital technology, namely signal processors, these 2 frequency domain algorithms may be investigated in order to implement them in voice recognition. This research is concerned with real time, microprocessor based recognition algorithms.

Botros, Nazeih M.

1987-01-01

321

Signal processing for robotically assisted laser photocoagulation of the retina  

NASA Astrophysics Data System (ADS)

A new system for robotically assisted retinal surgery requires real-time signal processing of the reflectance signal from small targets on the retina. Laser photocoagulation is used extensively by ophthalmologists to treat retinal disorders such as diabetic retinopathy and retinal breaks. Currently, the procedure is performed manually and suffers from several drawbacks which a computer-assisted system could alleviate. Such a system is under development that will rapidly and safely place multiple therapeutic lesions at desired locations on the retina in a mater of seconds. This system provides real- time, motion-stabilized lesion placement for typical clinical irradiation times. A reflectance signal from a small target on the retina is used to derive high-speed tracking corrections to compensate for patient eye movement by adjusting the laser pointing angles. Another reflectance signal from a different small target on the retina is used to derive information to control the laser irradiation time which allows consistent lesion formation over any part of the retina. This paper describes the electro-optical system which dynamically measures the two reflectance signals, determines the appropriate reflectance parameters in real time, and controls laser pointing and irradiation time to meet the stated requirements.

Wright, Cameron H. G.; de Graaf, Peter W.; Barrett, Steven F.; Ferguson, R. D.

1999-10-01

322

A study of correlation technique on pyramid processed images  

Microsoft Academic Search

The pyramid algorithm is potentially a powerful tool for advanced television image processing and for pattern recognition.\\u000a An attempt is made to design and develop both hardware and software for a system which performs decomposition and reconstruction\\u000a of digitized images by implementing the Burt pyramid algorithm.\\u000a \\u000a In this work, an attempt is also made to study correlation performance on reconstructed

M. Sankar Kishore; K. Veerabhadra Rao

2000-01-01

323

Biological Signal Processing with a Genetic Toggle Switch  

PubMed Central

Complex gene regulation requires responses that depend not only on the current levels of input signals but also on signals received in the past. In digital electronics, logic circuits with this property are referred to as sequential logic, in contrast to the simpler combinatorial logic without such internal memory. In molecular biology, memory is implemented in various forms such as biochemical modification of proteins or multistable gene circuits, but the design of the regulatory interface, which processes the input signals and the memory content, is often not well understood. Here, we explore design constraints for such regulatory interfaces using coarse-grained nonlinear models and stochastic simulations of detailed biochemical reaction networks. We test different designs for biological analogs of the most versatile memory element in digital electronics, the JK-latch. Our analysis shows that simple protein-protein interactions and protein-DNA binding are sufficient, in principle, to implement genetic circuits with the capabilities of a JK-latch. However, it also exposes fundamental limitations to its reliability, due to the fact that biological signal processing is asynchronous, in contrast to most digital electronics systems that feature a central clock to orchestrate the timing of all operations. We describe a seemingly natural way to improve the reliability by invoking the master-slave concept from digital electronics design. This concept could be useful to interpret the design of natural regulatory circuits, and for the design of synthetic biological systems. PMID:23874595

Hillenbrand, Patrick; Fritz, Georg; Gerland, Ulrich

2013-01-01

324

The effects of notch filters on the correlation properties of a PN signal  

NASA Technical Reports Server (NTRS)

With wideband pseudo-noise (PN) communications systems, it is sometimes desirable to supplement the inherent interference rejection capabilities by adding notch filters to attenuate relatively narrowband interference. This correspondence presents an investigation of the effects of notch filters on the performance of PN correlation receivers. A theoretical analysis of the correlation drop due to filter distortion has been conducted and confirmed by experimentation. Additional measurements and analysis have established the trade-off between correlation drop and interference suppression as a function of interference bandwidth. A typical result is that by incurring a penalty of a 1-dB drop in correlation peak, interfering signals having bandwidths of 2 to 3% of the PN chip rate can be attenuated by 25 dB.

Sussman, S. M.; Ferrari, E. J.

1974-01-01

325

Noise-benefit forbidden-interval theorems for threshold signal detectors based on cross correlations  

NASA Astrophysics Data System (ADS)

We show that the main forbidden interval theorems of stochastic resonance hold for a correlation performance measure. Earlier theorems held only for performance measures based on mutual information or the probability of error detection. Forbidden interval theorems ensure that a threshold signal detector benefits from deliberately added noise if the average noise does not lie in an interval that depends on the threshold value. We first show that this result holds for correlation for all finite-variance noise and for all forms of infinite-variance stable noise. A second forbidden-interval theorem gives necessary and sufficient conditions for a local noise benefit in a bipolar signal system when the noise comes from a location-scale family. A third theorem gives a general condition for a local noise benefit for arbitrary signals with finite second moments and for location-scale noise. This result also extends forbidden intervals to forbidden bands of parameters. A fourth theorem gives necessary and sufficient conditions for a local noise benefit when both the independent signal and noise are normal. A final theorem derives necessary and sufficient conditions for forbidden bands when using arrays of threshold detectors for arbitrary signals and location-scale noise.

Mitaim, Sanya; Kosko, Bart

2014-11-01

326

Noise-benefit forbidden-interval theorems for threshold signal detectors based on cross correlations.  

PubMed

We show that the main forbidden interval theorems of stochastic resonance hold for a correlation performance measure. Earlier theorems held only for performance measures based on mutual information or the probability of error detection. Forbidden interval theorems ensure that a threshold signal detector benefits from deliberately added noise if the average noise does not lie in an interval that depends on the threshold value. We first show that this result holds for correlation for all finite-variance noise and for all forms of infinite-variance stable noise. A second forbidden-interval theorem gives necessary and sufficient conditions for a local noise benefit in a bipolar signal system when the noise comes from a location-scale family. A third theorem gives a general condition for a local noise benefit for arbitrary signals with finite second moments and for location-scale noise. This result also extends forbidden intervals to forbidden bands of parameters. A fourth theorem gives necessary and sufficient conditions for a local noise benefit when both the independent signal and noise are normal. A final theorem derives necessary and sufficient conditions for forbidden bands when using arrays of threshold detectors for arbitrary signals and location-scale noise. PMID:25493756

Mitaim, Sanya; Kosko, Bart

2014-11-01

327

Analysis of cross-correlations in electroencephalogram signals as an approach to proactive diagnosis of schizophrenia  

NASA Astrophysics Data System (ADS)

We apply flicker-noise spectroscopy (FNS), a time series analysis method operating on structure functions and power spectrum estimates, to study the clinical electroencephalogram (EEG) signals recorded in children/adolescents (11 to 14 years of age) with diagnosed schizophrenia-spectrum symptoms at the National Center for Psychiatric Health (NCPH) of the Russian Academy of Medical Sciences. The EEG signals for these subjects were compared with the signals for a control sample of chronically depressed children/adolescents. The purpose of the study is to look for diagnostic signs of subjects' susceptibility to schizophrenia in the FNS parameters for specific electrodes and cross-correlations between the signals simultaneously measured at different points on the scalp. Our analysis of EEG signals from scalp-mounted electrodes at locations F3 and F4, which are symmetrically positioned in the left and right frontal areas of cerebral cortex, respectively, demonstrates an essential role of frequency-phase synchronization, a phenomenon representing specific correlations between the characteristic frequencies and phases of excitations in the brain. We introduce quantitative measures of frequency-phase synchronization and systematize the values of FNS parameters for the EEG data. The comparison of our results with the medical diagnoses for 84 subjects performed at NCPH makes it possible to group the EEG signals into 4 categories corresponding to different risk levels of subjects' susceptibility to schizophrenia. We suggest that the introduced quantitative characteristics and classification of cross-correlations may be used for the diagnosis of schizophrenia at the early stages of its development.

Timashev, Serge F.; Panischev, Oleg Yu.; Polyakov, Yuriy S.; Demin, Sergey A.; Kaplan, Alexander Ya.

2012-02-01

328

Signal processing methodologies for an acoustic fetal heart rate monitor  

NASA Technical Reports Server (NTRS)

Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

Pretlow, Robert A., III; Stoughton, John W.

1992-01-01

329

Communications, Signal Processing, and Telemetering Research Program Review  

NASA Technical Reports Server (NTRS)

A Communications, Signal Processing, and Telemetering Research Program Review was held on February 23, 1999. Research conducted under the grant was presented and reviewed, for progress, and for possible technology transfers. The research reviewed was in the following areas: (1) Bandwidth-efficient Modulation and nonlinear equalization; (2) Investigation of an architecture for parallel signal processing applicable to communications problems; (3)Coded partial response over satellites; (4) synchronization at Low SNR; (5) Serial concatenated convolutional codes and some implementation issues on high rate turbo codes; (6) Flight experiments; (7) Real time doppler tracking; (8) Space protocol testing; (9) Lightweight optical communications without carrying a laser in space. The presentations are given by the graduate students who performed the research.

1999-01-01

330

Developments in signal processing and interpretation in laser tapping  

NASA Astrophysics Data System (ADS)

A novel technique, called laser-tapping, based on the thermoelastic excitation by laser like laser-ultrasonics has been previously introduced for inspecting honeycomb and foam core structures. If the top skin is delaminated or detached from the substrate, the detached layer is driven into vibration. The interpretation of the vibrations in terms of Lamb wave resonances is first discussed for a flat bottom hole configuration and then used to determine appropriate signal processing for samples such as honeycomb structures.

Perton, M.; Neron, C.; Blouin, A.; Monchalin, J.-P.

2013-01-01

331

Programmable rate modem utilizing digital signal processing techniques  

NASA Technical Reports Server (NTRS)

The need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either Binary Phase Shift Keying (BPSK) or Quadrature Phase Shift Keying (QPSK) modulation is discussed. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. The design trade-offs in each portion of the modulator and demodulator subsystem are outlined.

Naveh, Arad

1992-01-01

332

Cathedral-II: A Silicon Compiler for Digital Signal Processing  

Microsoft Academic Search

The article describes the status of work at IMEC on the Cathedral-II silicon compiler. The compiler was developed to synthesize synchronous multiprocessor system chips for digital signal processing. It is a continuation of work on the Cathedral-I operational silicon compiler for bit-serial digital filters. Cathedral-II is based on a ¿meet in the middle¿ design method that encourages a total separation

H. De Man; J. Rabaey; L. Claesen

1986-01-01

333

Flash Signal Processing and NAND/ReRAM SSD  

NASA Astrophysics Data System (ADS)

The widespread use of NAND Flash memories in SSDs has unleashed new avenues of innovation for the enterprise and client computing. System-wide architectural changes are required to make full use of the advantages of SSDs in terms of performance, reliability and power. Signal processing technologies are becoming more and more popular to countermeasure all the parasitic effects of a Flash NAND array: the first part of this chapter deals with such techniques.

Takeuchi, K.

334

IC signal-processing circuit for TV receivers  

Microsoft Academic Search

An IC signal-processing circuit that can be applied in both black-and-white and color receivers is described. The integrated circuit combines the following functions: video preamplifier; keyed AGC detector, operating on top sync level; AGC amplifier for IF and tuner control; noise canceling circuits for AGC and sync circuits; sync separator; automatic horizontal sync; and vertical sync pulse separator. Due to

A. Cense; J. Rongen

1969-01-01

335

Signal Processing Techniques for Data Confidentiality in OCDMA Access Networks  

Microsoft Academic Search

This chapter focuses on several imminent security applications in optical CDMA networks where the strong potentials of optical\\u000a signal processing could be leveraged. As one of the dominant technologies in wireless communications, the unique features\\u000a of CDMA have attracted wide attention in many optical network-ing areas. We explored the security properties of optical CDMA\\u000a networks enhanced by the aid of

Yue-Kai Huang; Paul Toliver; Paul R. Prucnal

336

Particle image velocimetry correlation signal-to-noise ratio metrics and measurement uncertainty quantification  

NASA Astrophysics Data System (ADS)

In particle image velocimetry (PIV) the measurement signal is contained in the recorded intensity of the particle image pattern superimposed on a variety of noise sources. The signal-to-noise-ratio (SNR) strength governs the resulting PIV cross correlation and ultimately the accuracy and uncertainty of the resulting PIV measurement. Hence we posit that correlation SNR metrics calculated from the correlation plane can be used to quantify the quality of the correlation and the resulting uncertainty of an individual measurement. In this paper we extend the original work by Charonko and Vlachos and present a framework for evaluating the correlation SNR using a set of different metrics, which in turn are used to develop models for uncertainty estimation. Several corrections have been applied in this work. The SNR metrics and corresponding models presented herein are expanded to be applicable to both standard and filtered correlations by applying a subtraction of the minimum correlation value to remove the effect of the background image noise. In addition, the notion of a ‘valid’ measurement is redefined with respect to the correlation peak width in order to be consistent with uncertainty quantification principles and distinct from an ‘outlier’ measurement. Finally the type and significance of the error distribution function is investigated. These advancements lead to more robust and reliable uncertainty estimation models compared with the original work by Charonko and Vlachos. The models are tested against both synthetic benchmark data as well as experimental measurements. In this work, {{U}68.5} uncertainties are estimated at the 68.5% confidence level while {{U}95} uncertainties are estimated at 95% confidence level. For all cases the resulting calculated coverage factors approximate the expected theoretical confidence intervals, thus demonstrating the applicability of these new models for estimation of uncertainty for individual PIV measurements.

Xue, Zhenyu; Charonko, John J.; Vlachos, Pavlos P.

2014-11-01

337

Nonlinear fiber applications for ultrafast all-optical signal processing  

NASA Astrophysics Data System (ADS)

In the present dissertation different aspects of all-optical signal processing, enabled by the use of nonlinear fibers, are studied. In particular, we focus on applications of a novel heavily GeO2-doped (HD) nonlinear fiber, that appears to be superior to many other types of nonlinear fibers because of its high nonlinearity and suitability for the use in nonlinear optical loop mirrors (NOLMs). Different functions, such as all-optical switching, thresholding, and wavelength conversion, are demonstrated with the HD fibers in the NOLM configuration. These basic functions are later used for realization of ultrafast time-domain demultiplexers, clock recovery, detectors of short pulses in stealth communications, and primitive elements for analog computations. Another important technology that benefits from the use of nonlinear fiber-based signal processing is optical code-division multiple access (CDMA). It is shown in both theory and experiment that all-optical thresholding is a unique way of improving existing detection methods for optical CDMA. Also, it is the way of implementation of true asynchronous optical spread-spectrum networks, which allows full realization of optical CDMA potential. Some aspects of quantum signal processing and manipulation of quantum states are also studied in this work. It is shown that propagation and collisions of Thirring solitons lead to a substantial squeezing of quantum states, which may find applications for generation of squeezed light.

Kravtsov, Konstantin

338

Multichannel detection for correlated non-Gaussian random processes based on innovations  

NASA Astrophysics Data System (ADS)

This paper addresses the problem of multichannel signal detection in additive correlated non- Gaussian noise using the innovations approach. While this problem has been addressed extensively for the case of additive Gaussian noise, the corresponding problem for the non- Gaussian case has received limited attention. This is due to the fact that there is no unique specification for the joint probability density function (PDF) of N correlated non-Gaussian random variables. We overcome this problem by using the theory of spherically invariant random processes (SIRP) and derive the innovations based detectors. It is found that the optimal estimators for obtaining the innovations processes are linear and that the resulting detector is canonical for the class of PDFs arising from SIRPs.

Rangaswamy, Muralidhar; Weiner, Donald D.; Michels, James H.

1993-09-01

339

High-Speed Digital Signal Processing Method for Detection of Repeating Earthquakes Using GPGPU-Acceleration  

NASA Astrophysics Data System (ADS)

Repeating earthquakes are occurring on the similar asperity at the plate boundary. These earthquakes have an important property; the seismic waveforms observed at the identical observation site are very similar regardless of their occurrence time. The slip histories of repeating earthquakes could reveal the existence of asperities: The Analysis of repeating earthquakes can detect the characteristics of the asperities and realize the temporal and spatial monitoring of the slip in the plate boundary. Moreover, we are expecting the medium-term predictions of earthquake at the plate boundary by means of analysis of repeating earthquakes. Although the previous works mostly clarified the existence of asperity and repeating earthquake, and relationship between asperity and quasi-static slip area, the stable and robust method for automatic detection of repeating earthquakes has not been established yet. Furthermore, in order to process the enormous data (so-called big data) the speedup of the signal processing is an important issue. Recently, GPU (Graphic Processing Unit) is used as an acceleration tool for the signal processing in various study fields. This movement is called GPGPU (General Purpose computing on GPUs). In the last few years the performance of GPU keeps on improving rapidly. That is, a PC (personal computer) with GPUs might be a personal supercomputer. GPU computing gives us the high-performance computing environment at a lower cost than before. Therefore, the use of GPUs contributes to a significant reduction of the execution time in signal processing of the huge seismic data. In this study, first, we applied the band-limited Fourier phase correlation as a fast method of detecting repeating earthquake. This method utilizes only band-limited phase information and yields the correlation values between two seismic signals. Secondly, we employ coherence function using three orthogonal components (East-West, North-South, and Up-Down) of seismic data as a detailed analysis of repeating earthquakes. This method gives us the correlation between two seismic data at each frequency. Then, we evaluate the effectiveness of these methods. Moreover, we also examined the GPGPU acceleration technique for these methods. We compare the execution time between GPU (NVIDIA GeForce GTX 580) and CPU (Intel Core i7 960) processing. The parameters of both analyses are on equal terms. In case of band limited phase only correlation, the obtained results indicate that single GPU is ca. 8.0 times faster than 4-core CPU (auto-optimization with OpenMP). On the other hand, GPU is times as fast as CPU. And in case of coherence function using three components, GPU is 12.7 times as fast as CPU. This study examines the high-speed signal processing of huge seismic data using the GPU architecture. It was found that both band-limited Fourier phase correlation and coherence function using three orthogonal components are effective, and that the GPGPU-based acceleration for the temporal signal processing is very useful. We will employ the multi-GPU computing, and expand the GPGPU-based high-speed signal processing framework for the detection of repeating earthquakes in the future.

Kawakami, Taiki; Okubo, Kan; Uchida, Naoki; Takeuchi, Nobunao; Matsuzawa, Toru

2013-04-01

340

Influence of probe pressure on the diffuse correlation spectroscopy blood flow signal: extra-cerebral contributions  

PubMed Central

A pilot study explores relative contributions of extra-cerebral (scalp/skull) versus brain (cerebral) tissues to the blood flow index determined by diffuse correlation spectroscopy (DCS). Microvascular DCS flow measurements were made on the head during baseline and breath-holding/hyperventilation tasks, both with and without pressure. Baseline (resting) data enabled estimation of extra-cerebral flow signals and their pressure dependencies. A simple two-component model was used to derive baseline and activated cerebral blood flow (CBF) signals, and the DCS flow indices were also cross-correlated with concurrent Transcranial Doppler Ultrasound (TCD) blood velocity measurements. The study suggests new pressure-dependent experimental paradigms for elucidation of blood flow contributions from extra-cerebral and cerebral tissues. PMID:23847725

Mesquita, Rickson C.; Schenkel, Steven S.; Minkoff, David L.; Lu, Xiangping; Favilla, Christopher G.; Vora, Patrick M.; Busch, David R.; Chandra, Malavika; Greenberg, Joel H.; Detre, John A.; Yodh, A. G.

2013-01-01

341

Information processing correlates of a size-contrast illusion  

PubMed Central

Perception is often influenced by context. A well-known class of perceptual context effects is perceptual contrast illusions, in which proximate stimulus regions interact to alter the perception of various stimulus attributes, such as perceived brightness, color and size. Although the phenomenal reality of contrast effects is well documented, in many cases the connection between these illusions and how information is processed by perceptual systems is not well understood. Here, we use noise as a tool to explore the information processing correlates of one such contrast effect: the Ebbinghaus–Titchener size-contrast illusion. In this illusion, the perceived size of a central dot is significantly altered by the sizes of a set of surrounding dots, such that the presence of larger surrounding dots tends to reduce the perceived size of the central dot (and vise versa). In our experiments, we first replicated previous results that have demonstrated the subjective reality of the Ebbinghaus–Titchener illusion. We then used visual noise in a detection task to probe the manner in which observers processed information when experiencing the illusion. By correlating the noise with observers' classification decisions, we found that the sizes of the surrounding contextual elements had a direct influence on the relative weight observers assigned to regions within and surrounding the central element. Specifically, observers assigned relatively more weight to the surrounding region and less weight to the central region in the presence of smaller surrounding contextual elements. These results offer new insights into the connection between the subjective experience of size-contrast illusions and their associated information processing correlates. PMID:24600430

Gold, Jason M.

2014-01-01

342

Signal processing techniques for stepped frequency ultra-wideband radar  

NASA Astrophysics Data System (ADS)

The U.S. Army Research Laboratory (ARL) has developed the impulse-based, ground vehicle-based, forward-looking ultra-wideband (UWB), synthetic aperture radar (SAR) to detect concealed targets. Although the impulse-based architecture offers its own advantages, one of the important challenges is that when using this architecture it is very difficult to transmit a radar signal with an arbitrary bandwidth and shape. This feature is crucial for the radar to be compliant with the local frequency authority. In addition, being able to transmit signals with an arbitrary spectral shape is an important step in creating the next generation of smart (cognitive) radars. Therefore, we have designed a next-generation prototype radar to take advantage of the stepped frequency architecture. The design and building of the radar hardware is underway. In this paper, we study the radar transmit and acquisition scheme; the trade-offs between SAR image performance and various key radar parameters; and data reconstruction techniques for radar signals with an arbitrary spectrum. This study demonstrates performance, provides some guidelines for the radar design, and serves as a foundation for the signal and image processing stage.

Nguyen, Lam

2014-05-01

343

Overview of frequency bandwidth determination techniques of useful signal in case of leaks detection by correlation method  

NASA Astrophysics Data System (ADS)

In this paper an overview of useful signal detection methods on the background of intense noise and limits determination methods of useful signal is presented. The following features are considered: peculiarities of usage of correlation analysis, cross-amplitude spectrum, coherence function, cross-phase spectrum, time-frequency correlation function in case of frequency limits determination as well as leaks detection in pipelines. The possibility of using time-frequency correlation function for solving above named issues is described. Time- frequency correlation function provides information about the signals correlation for each of the investigated frequency bands. Data about location of peaks on the surface plot of a time- frequency correlation function allows making an assumption about the spectral composition of useful signal and its frequency boundaries.

Faerman, V. A.; Avramchuk, V. S.; Luneva, E. E.

2014-10-01

344

Two-dimensional compression of surface electromyographic signals using column-correlation sorting and image encoders.  

PubMed

We present a new preprocessing technique for two-dimensional compression of surface electromyographic (S-EMG) signals, based on correlation sorting. We show that the JPEG2000 coding system (originally designed for compression of still images) and the H.264/AVC encoder (video compression algorithm operating in intraframe mode) can be used for compression of S-EMG signals. We compare the performance of these two off-the-shelf image compression algorithms for S-EMG compression, with and without the proposed preprocessing step. Compression of both isotonic and isometric contraction S-EMG signals is evaluated. The proposed methods were compared with other S-EMG compression algorithms from the literature. PMID:19963967

Costa, Marcus V C; Carvalho, Joao L A; Berger, Pedro A; Zaghetto, Alexandre; da Rocha, Adson F; Nascimento, Francisco A O

2009-01-01

345

Correlated Variations in The Parameters That Regulate Dendritic Calcium Signaling in Mouse Retinal Ganglion Cells  

PubMed Central

The amplitude and time course of stimulus evoked second messenger signals carried by intracellular changes in free calcium ([Ca]free) depend on the total influx of Ca2+, the fraction bound to endogenous buffer and the rate of extrusion. Estimates of the values of these three parameters in proximal dendrites of 15 mouse alpha retinal ganglion cells were made using the “added buffer” method and found to vary greatly from one experiment to the next. The variations in the measured parameters were strongly correlated across the sample of cells. This reduced the variability in the amplitude and time course of the dendritic Ca2+ signal and suggests that the expression of Ca2+ channels, binding proteins and extrusion mechanisms is homeostatically coordinated to maintain the amplitude and kinetics of the Ca2+ signal within a physiologically appropriate range. PMID:22171038

Gartland, Andrew J.; Detwiler, Peter B.

2012-01-01

346

Biophoton signal transmission and processing in the brain.  

PubMed

The transmission and processing of neural information in the nervous system plays a key role in neural functions. It is well accepted that neural communication is mediated by bioelectricity and chemical molecules via the processes called bioelectrical and chemical transmission, respectively. Indeed, the traditional theories seem to give valuable explanations for the basic functions of the nervous system, but difficult to construct general accepted concepts or principles to provide reasonable explanations of higher brain functions and mental activities, such as perception, learning and memory, emotion and consciousness. Therefore, many unanswered questions and debates over the neural encoding and mechanisms of neuronal networks remain. Cell to cell communication by biophotons, also called ultra-weak photon emissions, has been demonstrated in several plants, bacteria and certain animal cells. Recently, both experimental evidence and theoretical speculation have suggested that biophotons may play a potential role in neural signal transmission and processing, contributing to the understanding of the high functions of nervous system. In this paper, we review the relevant experimental findings and discuss the possible underlying mechanisms of biophoton signal transmission and processing in the nervous system. PMID:24461927

Tang, Rendong; Dai, Jiapei

2014-10-01

347

Highly scalable hardware accelerator for digital signal processing  

NASA Astrophysics Data System (ADS)

In this paper, a highly scalable hardware accelerator design for digital signal processing is presented. The key features of this accelerator are minimum I/O operations, highly scalable massive parallelism, easy programming, and modularity and regularity. With a very large register file (> 1000) per processing element, the reuse factor per datum in this accelerator can be increased significantly (as compared to traditional DSP architectures). System performance is improved because the amount of data transfer between the on-chip cache and the off-chip cache/memory is reduced by the same factor. Since the basic building block of this accelerator is simply a VLSI chip with several processing elements, scalable massive parallelism can be achieved by connecting multiple chips together in a SIMD `vector- like' fashion. Finally, programming of this accelerometer is not difficult because it is operated under the SIMD `vector-like' mode. With the expected VLSI technology in the next few years, the throughput of one single accelerator chip can approach GFLOPs performance. Hence, the high computing power needed by digital signal processing applications can be provided by just connecting a small number of this chip together.

Chi, Chi-Hung; Lau, Siu-Chung

1994-10-01

348

Oxytocin effects on neural correlates of self-referential processing.  

PubMed

Oxytocin (OT) influences how humans process information about others. Whether OT affects the processing of information about oneself remains unknown. Using a double-blind, placebo-controlled within-subject design, we recorded event-related potentials (ERPs) from adults during trait judgments about oneself and a celebrity and during judgments on word valence, after intranasal OT or placebo administration. We found that OT vs. placebo treatment reduced the differential amplitudes of a fronto-central positivity at 220-280 ms (P2) during self- vs. valence-judgments. OT vs. placebo treatment tended to reduce the differential amplitude of a late positive potential at 520-1000 ms (LPP) during self-judgments but to increase the differential LPP amplitude during other-judgments. OT effects on the differential P2 and LPP amplitudes to self- vs. celebrity-judgments were positively correlated with a measure of interdependence of self-construals. Thus OT modulates the neural correlates of self-referential processing and this effect varies as a function of interdependence. PMID:23965321

Liu, Yi; Sheng, Feng; Woodcock, Kate A; Han, Shihui

2013-10-01

349

Gallium arsenide enhances digital signal processing in electronic warfare  

NASA Astrophysics Data System (ADS)

The higher electron mobility and velocity of GaAs digital signal processing IC devices for electronic warfare (EW) allow operation times that are several times faster than those of ICs based on silicon. Particular benefits are foreseen for the response time and broadband capability of ECM systems. Many data manipulation methods can be implemented in emitter-coupled logic (ECL) GaAs devices, and digital GaAs RF memories are noted to show great promise for improved ECM system performance while encompassing microwave frequency and chirp signal synthesis, repeater jamming, and multiple false target generation. EW digital frequency synthesizers are especially in need of GaAS IC technology, since bandwidth and resolution have been limited by ECL technology to about 250 MHz.

Hoffman, B.; Apte, D.

1985-07-01

350

Information processing and signal integration in bacterial quorum sensing  

NASA Astrophysics Data System (ADS)

Bacteria communicate with each other using secreted chemical signaling molecules called autoinducers (AIs) in a process known as quorum sensing. Quorum sensing enables bacteria to collectively regulate their behavior depending on the number and/or species of bacteria present. The quorum-sensing network of the marine-bacteria Vibrio harveyi consists of three AIs encoding distinct ecological information, each detected by its own histidine-kinase sensor protein. The sensor proteins all phosphorylate a common response regulator and transmit sensory information through a shared phosphorelay that regulates expression of downstream quorum-sensing genes. Despite detailed knowledge of the Vibrio quorum-sensing circuit, it is still unclear how and why bacteria integrate information from multiple input signals to coordinate collective behaviors. Here we develop a mathematical framework for analyzing signal integration based on Information Theory and use it to show that bacteria must tune the kinase activities of sensor proteins in order to transmit information from multiple inputs. This is demonstrated within a quantitative model that allows us to quantify how much Vibrio's learn about individual inputs and explains experimentally measured input-output relations. Furthermore, we predicted and experimentally verified that bacteria manipulate the production rates of AIs in order to increase information transmission and argue that the quorum-sensing circuit is designed to coordinate a multi-cellular developmental program. Our results show that bacteria can successfully learn about multiple signals even when they are transmitted through a shared pathway and suggest that Information Theory may be a powerful tool for analyzing biological signaling networks.

Mehta, Pankaj

2009-03-01

351

Approaches to Chemical and Biochemical Information and Signal Processing  

NASA Astrophysics Data System (ADS)

We outline models and approaches for error control required to prevent buildup of noise when ``gates'' and other ``network elements'' based on (bio)chemical reaction processes are utilized to realize stable, scalable networks for information and signal processing. We also survey challenges and possible future research. [4pt] [1] Control of Noise in Chemical and Biochemical Information Processing, V. Privman, Israel J. Chem. 51, 118-131 (2010).[0pt] [2] Biochemical Filter with Sigmoidal Response: Increasing the Complexity of Biomolecular Logic, V. Privman, J. Halamek, M. A. Arugula, D. Melnikov, V. Bocharova and E. Katz, J. Phys. Chem. B 114, 14103-14109 (2010).[0pt] [3] Towards Biosensing Strategies Based on Biochemical Logic Systems, E. Katz, V. Privman and J. Wang, in: Proc. Conf. ICQNM 2010 (IEEE Comp. Soc. Conf. Publ. Serv., Los Alamitos, California, 2010), pages 1-9.

Privman, Vladimir

2012-02-01

352

Signal processing with fractional lower order moments: stable processes and their applications  

Microsoft Academic Search

Non-Gaussian statistical signal processing is important when signals and\\/or noise deviate from the ideal Gaussian model. Stable distributions are among the most important non-Gaussian models. They share defining characteristics with the Gaussian distribution, such as the stability property and central limit theorems, and in fact include the Gaussian distribution as a limiting case. To help engineers better understand the stable

M. Shao; C. L. Nikias

1993-01-01

353

Digital Signal Processing Methods for Pixelated 3-D Position Sensitive Room-Temperature  

E-print Network

Digital Signal Processing Methods for Pixelated 3-D Position Sensitive Room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 II. Electronic Noise and Digital Filters . . . . . . . . . . . . . . . . 11 2.1 Introduction for Charge Collecting Signals . . . . 22 2.2.2 Optimal Filter for Transient signals . . . . . . . . . 26 2

He, Zhong

354

Stochastic simulation of spatially correlated geo-processes  

USGS Publications Warehouse

In this study, developments in the theory of stochastic simulation are discussed. The unifying element is the notion of Radon projection in Euclidean spaces. This notion provides a natural way of reconstructing the real process from a corresponding process observable on a reduced dimensionality space, where analysis is theoretically easier and computationally tractable. Within this framework, the concept of space transformation is defined and several of its properties, which are of significant importance within the context of spatially correlated processes, are explored. The turning bands operator is shown to follow from this. This strengthens considerably the theoretical background of the geostatistical method of simulation, and some new results are obtained in both the space and frequency domains. The inverse problem is solved generally and the applicability of the method is extended to anisotropic as well as integrated processes. Some ill-posed problems of the inverse operator are discussed. Effects of the measurement error and impulses at origin are examined. Important features of the simulated process as described by geomechanical laws, the morphology of the deposit, etc., may be incorporated in the analysis. The simulation may become a model-dependent procedure and this, in turn, may provide numerical solutions to spatial-temporal geologic models. Because the spatial simu??lation may be technically reduced to unidimensional simulations, various techniques of generating one-dimensional realizations are reviewed. To link theory and practice, an example is computed in detail. ?? 1987 International Association for Mathematical Geology.

Christakos, G.

1987-01-01

355

Correlation technique for the compensation of diffraction widening of optical reference signals.  

PubMed

Two-grating measurement systems are routinely employed for high-resolution measurements of angular and linear displacement. Usually, these systems incorporate zero reference codes (ZRCs) to obtain a zero reference signal (ZRS), which is used as a stage-homing signal. This signal provides absolute information of the position to the otherwise relative information provided by the two-grating incremental subsystems. A zero reference signal is commonly obtained illuminating the superposition of two identical pseudorandom codes and registering the transmitted light by means of a photodiode. To increase the resolution of the system, a reduction of the grating period and the ZRC widths is required. Due to this reduction, the diffractive effects produce a widening of the ZRS and, in turn, a loss of the measuring accuracy. In this work, we propose a method to narrow the distorted signal obtained with a Lau-based encoder, reinstating the accuracy of the ZRS. The method consists of the inclusion of a correlation mask on the detector. A theoretical model to design the mask has been developed, and experimental results have been obtained that validate the proposed technique. PMID:19721672

Sáez-Landete, José; Alonso, José; Sanchez-Brea, Luis Miguel; Morlanes, Tomás; Bernabeu, Eusebio

2009-09-01

356

FPGA-based signal processing method of automatic interference comparator  

NASA Astrophysics Data System (ADS)

Automatic interference comparator (AIC) is a high precision one-dimensional length measurement machine for investigation and calibrations of line scales, linear encoders and length gauges. This paper emphasizes a novel electronic subdivision method for the AIC to realize precision measurement, which is composed of integer fringe counting, fraction fringe counting and electronic strobe. The realization of the whole system is based on FPGA. A standard line scale has been calibrated by this method on the AIC of the National Institute of Metrology(NIM) in China. The experimental results show the measurement repeatability is less than 7.5 nm, which demonstrates the feasibility of the new signal processing method.

Wang, Zhongyu; Chang, Haitao; Gao, Hongtang; Ye, Xiaoyou

2013-10-01

357

Iowegian's dspGuru: Digital Signal Processing Central  

NSDL National Science Digital Library

dspGuru is a site dedicated to digital signal processing (DSP) designers. It has a good collection of resources for both beginners and seasoned users. Many open-source software titles can be freely downloaded, ranging from implementations of DSP algorithms to compilers and other software development tools. Five frequently asked questions lists cover some important DSP subjects, like finite and infinite impulse response filters and Fourier transforms. There is also a section called Tribal Knowledge that is filled with common techniques and tricks that experienced DSP designers know, "but isn't in the textbooks."

358

DSPSR: Digital Signal Processing Software for Pulsar Astronomy  

NASA Astrophysics Data System (ADS)

DSPSR, written primarily in C++, is an open-source, object-oriented, digital signal processing software library and application suite for use in radio pulsar astronomy. The library implements an extensive range of modular algorithms for use in coherent dedispersion, filterbank formation, pulse folding, and other tasks. The software is installed and compiled using the standard GNU configure and make system, and is able to read astronomical data in 18 different file formats, including FITS, S2, CPSR, CPSR2, PuMa, PuMa2, WAPP, ASP, and Mark5.

van Straten, W.; Bailes, M.

2010-10-01

359

Signal Processing System for the CASA Integrated Project I Radars  

SciTech Connect

This paper describes the waveform design space and signal processing system for dual-polarization Doppler weather radar operating at X band. The performance of the waveforms is presented with ground clutter suppression capability and mitigation of range velocity ambiguity. The operational waveform is designed based on operational requirements and system/hardware requirements. A dual Pulse Repetition Frequency (PRF) waveform was developed and implemented for the first generation X-band radars deployed by the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA). This paper presents an evaluation of the performance of the waveforms based on simulations and data collected by the first-generation CASA radars during operations.

Bharadwaj, Nitin; Chandrasekar, V.; Junyent, Francesc

2010-09-01

360

Optical signal processing using mode-locked semiconductor laser diode  

NASA Astrophysics Data System (ADS)

We investigated ultrafast optical signal processing schemes utilizing mode-locked semiconductor laser diodes (MLLDs) for optical time-division multiplexing (OTDM) transmission at over 100 Gbit/s and developed a polarization-insensitive all-optical clock recovery scheme for an optical-electrical hybrid phase-locked loop (PLL) operating at 160 Gbit/s. In this scheme, the MLLD functions as a voltage-controlled oscillator to which the error signal is fed back by forming a closed loop with a semiconductor optical amplifier (SOA) used as a phase comparator and with a low-frequency component used as a filter. Cross-gain modulation in the SOA enables high-frequency PLL operation at 160 Gbit/s. A bulk active layer in the SOA with small polarization dependency is the origin of the polarization insensitive clock extraction. Testing of all-optical clock extraction on an OTDM transmission test bed of 254-km field-installed fibers (Dojima-Keihanna, 63.5 km, and four spans) at 160 Gbit/s showed that the measured root-mean-square timing jitter of the recovered clock signal was as low as 240 fs. This clock extraction scheme is thus practical for use in OTDM systems operating at over 100 Gbit/s.

Hashimoto, Y.; Kuribayashi, R.; Nakamura, S.; Ogura, I.

2006-10-01

361

Social signal processing for studying parent–infant interaction  

PubMed Central

Studying early interactions is a core issue of infant development and psychopathology. Automatic social signal processing theoretically offers the possibility to extract and analyze communication by taking an integrative perspective, considering the multimodal nature and dynamics of behaviors (including synchrony). This paper proposes an explorative method to acquire and extract relevant social signals from a naturalistic early parent–infant interaction. An experimental setup is proposed based on both clinical and technical requirements. We extracted various cues from body postures and speech productions of partners using the IMI2S (Interaction, Multimodal Integration, and Social Signal) Framework. Preliminary clinical and computational results are reported for two dyads (one pathological in a situation of severe emotional neglect and one normal control) as an illustration of our cross-disciplinary protocol. The results from both clinical and computational analyzes highlight similar differences: the pathological dyad shows dyssynchronic interaction led by the infant whereas the control dyad shows synchronic interaction and a smooth interactive dialog. The results suggest that the current method might be promising for future studies. PMID:25540633

Avril, Marie; Leclère, Chloë; Viaux, Sylvie; Michelet, Stéphane; Achard, Catherine; Missonnier, Sylvain; Keren, Miri; Cohen, David; Chetouani, Mohamed

2014-01-01

362

Signal transduction and information processing in mammalian taste buds  

PubMed Central

The molecular machinery for chemosensory transduction in taste buds has received considerable attention within the last decade. Consequently, we now know a great deal about sweet, bitter, and umami taste mechanisms and are gaining ground rapidly on salty and sour transduction. Sweet, bitter, and umami tastes are transduced by G-protein-coupled receptors. Salty taste may be transduced by epithelial Na channels similar to those found in renal tissues. Sour transduction appears to be initiated by intracellular acidification acting on acid-sensitive membrane proteins. Once a taste signal is generated in a taste cell, the subsequent steps involve secretion of neurotransmitters, including ATP and serotonin. It is now recognized that the cells responding to sweet, bitter, and umami taste stimuli do not possess synapses and instead secrete the neurotransmitter ATP via a novel mechanism not involving conventional vesicular exocytosis. ATP is believed to excite primary sensory afferent fibers that convey gustatory signals to the brain. In contrast, taste cells that do have synapses release serotonin in response to gustatory stimulation. The postsynaptic targets of serotonin have not yet been identified. Finally, ATP secreted from receptor cells also acts on neighboring taste cells to stimulate their release of serotonin. This suggests that there is important information processing and signal coding taking place in the mammalian taste bud after gustatory stimulation. PMID:17468883

2013-01-01

363

Multivariate analysis of correlation between electrophysiological and hemodynamic responses during cognitive processing.  

PubMed

Animal and human studies have frequently shown that in primary sensory and motor regions the BOLD signal correlates positively with high-frequency and negatively with low-frequency neuronal activity. However, recent evidence suggests that this relationship may also vary across cortical areas. Detailed knowledge of the possible spectral diversity between electrophysiological and hemodynamic responses across the human cortex would be essential for neural-level interpretation of fMRI data and for informative multimodal combination of electromagnetic and hemodynamic imaging data, especially in cognitive tasks. We applied multivariate partial least squares correlation analysis to MEG-fMRI data recorded in a reading paradigm to determine the correlation patterns between the data types, at once, across the cortex. Our results revealed heterogeneous patterns of high-frequency correlation between MEG and fMRI responses, with marked dissociation between lower and higher order cortical regions. The low-frequency range showed substantial variance, with negative and positive correlations manifesting at different frequencies across cortical regions. These findings demonstrate the complexity of the neurophysiological counterparts of hemodynamic fluctuations in cognitive processing. PMID:24518260

Kujala, Jan; Sudre, Gustavo; Vartiainen, Johanna; Liljeström, Mia; Mitchell, Tom; Salmelin, Riitta

2014-05-15

364

Palmo: pulse-based signal processing for programmable analog VLSI  

Microsoft Academic Search

This paper presents novel signaling and circuit techniques for the implementation of programmable analog and mixed signal very large scale integration (VLSI). The signaling technique uses pulsewidth modulated digital signals to convey analog signal information between programmable analog cells. A circuit for a generic programmable analog cell is introduced and is analyzed for harmonic distortion performance. The equivalence of the

Konstantinos Papathanasiou; Thomas Brandtner; Alister Hamilton

2002-01-01

365

On measuring surface wave phase velocity from station-station cross-correlation of ambient signal  

NASA Astrophysics Data System (ADS)

We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one method involves the time-domain cross-correlation of signal recorded at different stations; the other is based on frequency-domain cross-correlation, and requires finding the zero-crossings of the real part of the cross-correlation spectrum. Furthermore, the time-domain method, as implemented here and in the literature, practically involves the important approximation that interstation distance be large compared to seismic wavelength. In both cases, cross-correlations are ensemble-averaged over a relatively long period of time (1 yr). We verify that the two algorithms give consistent results, and infer that phase velocity can be successfully measured through ensemble-averaging of seismic ambient noise, further validating earlier studies that had followed either approach. The description of our experiment and its results is accompanied by a detailed though simplifed derivation of ambient-noise theory, writing out explicitly the relationships between the surface wave Green's function, ambient-noise cross-correlation and phase and group velocities.

Boschi, Lapo; Weemstra, Cornelis; Verbeke, Julie; Ekström, Göran; Zunino, Andrea; Giardini, Domenico

2013-01-01

366

Gravity Influences Top-Down Signals in Visual Processing  

PubMed Central

Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene. PMID:24400069

Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

2014-01-01

367

Gravity influences top-down signals in visual processing.  

PubMed

Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene. PMID:24400069

Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

2014-01-01

368

Compendium of digital signal processing Lapo Boschi (lapo.boschi@upmc.fr)  

E-print Network

Compendium of digital signal processing Lapo Boschi (lapo.boschi@upmc.fr) August 31, 2014 at http://www.dspguide.com. 1 Linear systems A signal is a description of how one parameter varies time. A system is any process that produces an output signal in response to an input signal

Boschi, Lapo

369

Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process  

E-print Network

Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process algebra) on the Extracellular signal Regulated Kinase (ERK) signalling pathway [1] through modelling in a Markovian process choices. The system which we consider is the Ras/Raf-1/MEK/ERK signalling path- way, as presented in [1

Gilmore, Stephen

370

Design and implementation of signal processing scheme in CDMA wireless location systems  

NASA Astrophysics Data System (ADS)

Subscriber radio location techniques for code division multiple access (CDMA) cellular networks has been studied extensively in recent years. The network-based angle of arrival (AOA), time difference of arrival (TDOA), and time of arrival (TOA) techniques offer solutions to the position estimation problem. In this paper, The signal processing scheme of wireless location system based IS-95 is presented, in which TOA of reverse access channel transmissions is measured using sub-correlation detection algorithms and TOA estimation accuracy is improved using second search. Furthermore, reverse access channel decoding is implemented used to identify access channel message type, mobile identification, and dialed number.

Yang, Tiejun; Fu, Hongliang

2012-01-01

371

Wavelet-Based Signal and Image Processing for Target Recognition  

NASA Astrophysics Data System (ADS)

The PI visited NSWC Dahlgren, VA, for six weeks in May-June 2002 and collaborated with scientists in the G33 TEAMS facility, and with Marilyn Rudzinsky of T44 Technology and Photonic Systems Branch. During this visit the PI also presented six educational seminars to NSWC scientists on various aspects of signal processing. Several items from the grant proposal were completed, including (1) wavelet-based algorithms for interpolation of 1-d signals and 2-d images; (2) Discrete Wavelet Transform domain based algorithms for filtering of image data; (3) wavelet-based smoothing of image sequence data originally obtained for the CRITTIR (Clutter Rejection Involving Temporal Techniques in the Infra-Red) project. The PI visited the University of Stellenbosch, South Africa to collaborate with colleagues Prof. B.M. Herbst and Prof. J. du Preez on the use of wavelet image processing in conjunction with pattern recognition techniques. The University of Stellenbosch has offered the PI partial funding to support a sabbatical visit in Fall 2003, the primary purpose of which is to enable the PI to develop and enhance his expertise in Pattern Recognition. During the first year, the grant supported publication of 3 referred papers, presentation of 9 seminars and an intensive two-day course on wavelet theory. The grant supported the work of two students who functioned as research assistants.

Sherlock, Barry G.

2002-11-01

372

Increasing signal processing sophistication in the calculation of the respiratory modulation of the photoplethysmogram (DPOP).  

PubMed

DPOP (?POP or Delta-POP) is a non-invasive parameter which measures the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive surrogate parameter for pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. Many groups have reported on the DPOP parameter and its correlation with PPV using various semi-automated algorithmic implementations. The study reported here demonstrates the performance gains made by adding increasingly sophisticated signal processing components to a fully automated DPOP algorithm. A DPOP algorithm was coded and its performance systematically enhanced through a series of code module alterations and additions. Each algorithm iteration was tested on data from 20 mechanically ventilated OR patients. Correlation coefficients and ROC curve statistics were computed at each stage. For the purposes of the analysis we split the data into a manually selected 'stable' region subset of the data containing relatively noise free segments and a 'global' set incorporating the whole data record. Performance gains were measured in terms of correlation against PPV measurements in OR patients undergoing controlled mechanical ventilation. Through increasingly advanced pre-processing and post-processing enhancements to the algorithm, the correlation coefficient between DPOP and PPV improved from a baseline value of R = 0.347 to R = 0.852 for the stable data set, and, correspondingly, R = 0.225 to R = 0.728 for the more challenging global data set. Marked gains in algorithm performance are achievable for manually selected stable regions of the signals using relatively simple algorithm enhancements. Significant additional algorithm enhancements, including a correction for low perfusion values, were required before similar gains were realised for the more challenging global data set. PMID:25209132

Addison, Paul S; Wang, Rui; Uribe, Alberto A; Bergese, Sergio D

2014-09-11

373

Peta-Flop Real Time Radio Astronomy Signal Processing Instrumentation and the CASPER Collaboration  

NASA Astrophysics Data System (ADS)

I will briefly describe next generation radio telescopes, such as HERA and the Square Kilometer Array (SKA), which will require 1E15 to 1E17 operations per second of real time processing. I'll present some of the new architectures we've used to develop a variety of heterogeneous FPGA-GPU-CPU based signal processing systems for such telescopes, including spectrometers, correlators, and beam formers. I will also describe the CASPER collaboration, which has developed architectures, open source programming tools, libraries and reference designs that make it relatively easy to develop a variety of scalable, upgradeable, fault tolerant, low power, real time digital signal processing instrumentation. CASPER utilizes commercial 10Gbit and 40 Gbit ethernet switches to interconnect open source general purpose field programmable gate array (FPGA) boards with GPUs and software modules. CASPER collaborators at hundreds of universities, government labs and observatories have used these techniques to rapidly develop and deploy a variety of correlators, beamformers, spectrometers, pulsar/transient machines, and VLBI instrumentation. CASPER instrumentation is also utilized in physics, medicine, genomics and engineering. Open source source hardware, software, libraries, tools, tutorials, reference designs, information about workshops, and how to join the collaboration are available at http://casper.berkeley.edu

Werthimer, Dan

2014-04-01

374

From Bursts to Back-Projection: Signal Processing Techniques for Earth and Planetary Observing Radars  

NASA Technical Reports Server (NTRS)

Discusses: (1) JPL Radar Overview and Historical Perspective (2) Signal Processing Needs in Earth and Planetary Radars (3) Examples of Current Systems and techniques (4) Future Perspectives in signal processing for radar missions

Rosen, Paul A.

2012-01-01

375

The molecular signalling processes underlying olfactory learning and memory formation in honeybees  

E-print Network

The molecular signalling processes underlying olfactory learning and memory formation in honeybees processes underlying olfactory learning and memory formation in intact animals. Applying innovative of dynamic signalling events that contribute to different facets of olfactory learning and memory formation

376

Informatics and Mathematical Modelling / Intelligent Signal Processing Mikkel Schmidt, Jan Larsen  

E-print Network

Informatics and Mathematical Modelling / Intelligent Signal Processing Mikkel Schmidt, Jan Larsen Wind Noise Reduction Using Non-negative Sparse Coding Mikkel N. Schmidt, Jan Larsen, Technical, Jan Larsen Informatics and Mathematical Modelling / Intelligent Signal Processing Wind Noise Reduction

377

Correlation Between Chemical Composition of Silver Alloys and Photothermal Radiometry Signals  

NASA Astrophysics Data System (ADS)

The development of nondestructive and noncontact techniques for evaluation of metallic materials is invaluable to metal characterization. The photothermal radiometry (PTR) amplitude and phase images of silver alloys were used to study the silver distribution in alloys rich in silver and copper for Ag concentrations between 37 mass% and 92 mass%. The silver concentration was determined using inductively coupled plasma. It was found that for Ag concentrations lower than 50 mass%, the PRT signals are governed by the thermal and optical properties of copper and vice versa. It was possible to establish a good correlation between the PTR amplitude and phase signal with the Ag concentration. This means that after calibration it is possible to determine the Ag concentration using nondestructive evaluation.

Rojas-Rodríguez, I.; Velázquez-Hernández, R.; Jaramillo-Vigueras, D.; Mendoza-López, M. L.; Millan-Malo, M.; Rodíguez-García, M. E.

2012-12-01

378

Color interpolation algorithm of CCD based on green components and signal correlation  

NASA Astrophysics Data System (ADS)

Signal CCD/CMOS sensors capture image information by covering the sensor surface with a color filter array(CFA). For each pixel, only one of three primary colors(red, green and blue) can pass through the color filter array(CFA). The other two missing color components are estimated by the values of the surrounding pixels. In Bayer array, the green components are half of the total pixels, but both red pixel and blue pixel components are quarter, so green components contain more information, which can be reference to color interpolation of red components and blue components. Based on this principle, in this paper, a simple and effective color interpolation algorithm based on green components and signal correlation for Bayer pattern images was proposed. The first step is to interpolate R, G and B components using the method-bilinear interpolation. The second step is to revise the results of bilinear interpolation by adding some green components on the results of bilinear interpolation. The calculation of the values to be added should consider the influence of correlation between the three channels. There are two major contributions in the paper. The first one is to demosaick G component more precisely. The second one is the spectral-spatial correlations between the three color channels is taken into consideration. At last, through MATLAB simulation experiments, experimental pictures and quantitative data for performance evaluation-Peak Signal to Noise Ratio(PSNR) were gotten. The results of simulation experiments show, compared with other color interpolation algorithms, the proposed algorithm performs well in both visual perception and PSNR measurement. And the proposed algorithm does not increase the complexity of calculation but ensures the real-time of system. Theory and experiments show the method is reasonable and has important engineering significance.

Liang, Xiaofen; Qiao, Weidong; Yang, Jianfeng; Xue, Bin; Qin, Jia

2013-09-01

379

Electrophysiological correlates of morphological processing in Chinese compound word recognition.  

PubMed

The present study investigated the electrophysiological correlates of morphological processing in Chinese compound word reading using a delayed repetition priming paradigm. Participants were asked to passively view lists of two-character compound words containing prime-target pairs separated by a few items. In a Whole Word repetition condition, the prime and target were the same real words (e.g., , manager-manager). In a Constituent repetition condition, the prime and target were swapped in terms of their constituent position (e.g., , the former is a pseudo-word and the later means nurse). Two ERP components including N200 and N400 showed repetition effects. The N200 showed a negative shift upon repetition in the Whole Word condition but this effect was delayed for the Constituent condition. The N400 showed comparable amplitude reduction across the two priming conditions. The results reveal different aspects of morphological processing with an early stage associated with N200 and a late stage with N400. There was also a possibility that the N200 effect reflect general cognitive processing, i.e., the detection of low-probability stimuli. PMID:24068994

Du, Yingchun; Hu, Weiping; Fang, Zhuo; Zhang, John X

2013-01-01

380

Electrophysiological correlates of morphological processing in Chinese compound word recognition  

PubMed Central

The present study investigated the electrophysiological correlates of morphological processing in Chinese compound word reading using a delayed repetition priming paradigm. Participants were asked to passively view lists of two-character compound words containing prime-target pairs separated by a few items. In a Whole Word repetition condition, the prime and target were the same real words (e.g., , manager-manager). In a Constituent repetition condition, the prime and target were swapped in terms of their constituent position (e.g., , the former is a pseudo-word and the later means nurse). Two ERP components including N200 and N400 showed repetition effects. The N200 showed a negative shift upon repetition in the Whole Word condition but this effect was delayed for the Constituent condition. The N400 showed comparable amplitude reduction across the two priming conditions. The results reveal different aspects of morphological processing with an early stage associated with N200 and a late stage with N400. There was also a possibility that the N200 effect reflect general cognitive processing, i.e., the detection of low-probability stimuli. PMID:24068994

Du, Yingchun; Hu, Weiping; Fang, Zhuo; Zhang, John X.

2013-01-01

381

Error reduction in laser remote sensing - Combined effects of cross correlation and signal averaging  

NASA Technical Reports Server (NTRS)

A systematic analysis is presented of the extent to which the accuracy of a differential-absorption lidar (DIAL) measurement may be improved by using the combined effects of signal averaging and temporal cross correlation. Previous studies which considered these effects separately are extended by incorporating both effects into a single analytical framework. In addition, experimental results involving lidar returns from a diffusely reflecting target using a dual-CO2 laser DIAL system with both heterodyne and direct detection are presented. These results are shown to be in good agreement with the theoretical analysis and help establish the limits of accuracy achievable under various experimental conditions.

Menyuk, N.; Killinger, D. K.; Menyuk, C. R.

1985-01-01

382

Strong Monogamies of No-Signaling Violations for Bipartite Correlation Bell Inequalities  

NASA Astrophysics Data System (ADS)

The phenomenon of monogamy of Bell inequality violations is interesting both from the fundamental perspective as well as in cryptographic applications such as the extraction of randomness and secret bits. In this article, we derive new and stronger monogamy relations for violations of Bell inequalities in general no-signaling theories. These relations are applicable to the class of binary output correlation inequalities known as xor games, and to free unique games. In many instances of interest, we show that the derived relation provides a significant strengthening over previously known results. Our result connects, for the first time, the property of monogamy with that crucial part of the Bell expression that is necessary for revealing a contradiction with local realistic predictions, thus shifting the paradigm in the field of monogamy of correlations.

Ramanathan, Ravishankar; Horodecki, Pawe?

2014-11-01

383

Strong monogamies of no-signaling violations for bipartite correlation bell inequalities.  

PubMed

The phenomenon of monogamy of Bell inequality violations is interesting both from the fundamental perspective as well as in cryptographic applications such as the extraction of randomness and secret bits. In this article, we derive new and stronger monogamy relations for violations of Bell inequalities in general no-signaling theories. These relations are applicable to the class of binary output correlation inequalities known as XOR games, and to free unique games. In many instances of interest, we show that the derived relation provides a significant strengthening over previously known results. Our result connects, for the first time, the property of monogamy with that crucial part of the Bell expression that is necessary for revealing a contradiction with local realistic predictions, thus shifting the paradigm in the field of monogamy of correlations. PMID:25479479

Ramanathan, Ravishankar; Horodecki, Pawe?

2014-11-21

384

Long-Range Correlations in the Sequence of Human Heartbeats and Other Biological Signals  

NASA Astrophysics Data System (ADS)

The sequence of heartbeat occurrence times provides information about the state of health of the heart. We used a variety of measures, including multiresolution wavelet analysis, to identify the form of the point process that describes the human heartbeat. These measures, which are based on both interbeat (R-R) intervals and counts (heart rate), have been applied to records for both normal and heart-failure patients drawn from a standard database, and various surrogate versions thereof. Several of these measures reveal scaling behavior (1/f-type fluctuations; long-range power-law correlations).(R. G. Turcott and M. C. Teich, Proc. SPIE) 2036 (Chaos in Biology and Medicine), 22--39 (1993). Essentially all of the R-R and count-based measures we investigated, including those that exhibit scaling, differ in statistically significant ways for the normal and heart-failure patients. The wavelet measures, however, reveal a heretofore unknown scale window, between 16 and 32 heartbeats, over which the magnitudes of the wavelet-coefficient variances fall into disjoint sets for the normal and heart-failure patients.(R. G. Turcott and M. C. Teich, Ann. Biomed. Eng.) 24, 269--293 (1996).^,(S. Thurner, M. C. Feurstein, and M. C. Teich, Phys. Rev. Lett.) (in press). This enables us to correctly classify every patient in the standard data set as either belonging to the heart-failure or normal group with 100% accuracy, thereby providing a clinically significant measure of the presence of heart-failure. Previous approaches have provided only statistically significant measures. The tradeoff between sensitivity and specificity for various salient measures, as a function of data length, is determined by the use of ROC analysis. A phase-space reconstruction based on generalized heart rate is used to obtain a putative attractor's capacity dimension. Though the dependence of this dimension on the embedding dimension is consistent with that of a low-dimensional dynamical system, surrogate-data analysis shows that identical behavior emerges from long-range temporal correlations in a stochastic process.^2 An integrate-and-fire model, comprising a fractal-Gaussian-noise kernel and Gaussian event-jittering,(S. Thurner, S. B. Lowen, M. C. Feurstein, C. Heneghan, H. G. Feichtinger, and M. C. Teich, Fractals) 5, No. 4 (1997). provides a realistic simulation of heartbeat sequences for both normal and heart-failure patients, over all time scales. These results could be of use in generating an artificial heartbeat that mimics the healthy heartbeat sequence for applications such as pacemakers. The presentation will be concluded with a brief discussion of the application of these methods to other unitary biological signals.

Teich, Malvin C.

1998-03-01

385

Improved Statistical Signal Processing of Nonstationary Random Processes Using Time-Warping  

NASA Astrophysics Data System (ADS)

A common assumption used in statistical signal processing of nonstationary random signals is that the signals are locally stationary. Using this assumption, data is segmented into short analysis frames, and processing is performed using these short frames. Short frames limit the amount of data available, which in turn limits the performance of statistical estimators. In this thesis, we propose a novel method that promises improved performance for a variety of statistical signal processing algorithms. This method proposes to estimate certain time-varying parameters of nonstationary signals and then use this estimated information to perform a time-warping of the data that compensates for the time-varying parameters. Since the time-warped data is more stationary, longer analysis frames may be used, which improves the performance of statistical estimators. We first examine the spectral statistics of two particular types of nonstationary random processes that are useful for modeling ship propeller noise and voiced speech. We examine the effect of time-varying frequency content on these spectral statistics, and in addition show that the cross-frequency spectral statistics of these signals contain significant additional information that is not usually exploited using a stationary assumption. This information, combined with our proposed method, promises improvements for a wide variety of applications in the future. We then describe and test an implementation of our time-warping method, the fan-chirp transform. We apply our method to two applications, detection of ship noise in a passive sonar application and joint denoising and dereverberation of speech. Our method yields improved results for both applications compared to conventional methods.

Wisdom, Scott Thomas

386

DESIGN OF A REAL-TIME DIGITAL SIGNAL PROCESSING AUDIO PROCESSING TECHNIQUE  

E-print Network

This thesis outlines the design of a real-time digital signal processing technique for pitch detection and analysis via spectral analysis. A sound’s musical pitch can be determined from its fundamental frequency, and a note that is said to be “out...

Jagielski, Christopher

2012-04-24

387

Electrophysiological correlates of the BOLD signal for EEG-informed fMRI.  

PubMed

Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are important tools in cognitive and clinical neuroscience. Combined EEG-fMRI has been shown to help to characterise brain networks involved in epileptic activity, as well as in different sensory, motor and cognitive functions. A good understanding of the electrophysiological correlates of the blood oxygen level-dependent (BOLD) signal is necessary to interpret fMRI maps, particularly when obtained in combination with EEG. We review the current understanding of electrophysiological-haemodynamic correlates, during different types of brain activity. We start by describing the basic mechanisms underlying EEG and BOLD signals and proceed by reviewing EEG-informed fMRI studies using fMRI to map specific EEG phenomena over the entire brain (EEG-fMRI mapping), or exploring a range of EEG-derived quantities to determine which best explain colocalised BOLD fluctuations (local EEG-fMRI coupling). While reviewing studies of different forms of brain activity (epileptic and nonepileptic spontaneous activity; cognitive, sensory and motor functions), a significant attention is given to epilepsy because the investigation of its haemodynamic correlates is the most common application of EEG-informed fMRI. Our review is focused on EEG-informed fMRI, an asymmetric approach of data integration. We give special attention to the invasiveness of electrophysiological measurements and the simultaneity of multimodal acquisitions because these methodological aspects determine the nature of the conclusions that can be drawn from EEG-informed fMRI studies. We emphasise the advantages of, and need for, simultaneous intracranial EEG-fMRI studies in humans, which recently became available and hold great potential to improve our understanding of the electrophysiological correlates of BOLD fluctuations. Hum Brain Mapp, 36:391-414, 2015. © 2014 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:25277370

Murta, Teresa; Leite, Marco; Carmichael, David W; Figueiredo, Patrícia; Lemieux, Louis

2015-01-01

388

Electrophysiological correlates of the BOLD signal for EEG-informed fMRI  

PubMed Central

Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are important tools in cognitive and clinical neuroscience. Combined EEG–fMRI has been shown to help to characterise brain networks involved in epileptic activity, as well as in different sensory, motor and cognitive functions. A good understanding of the electrophysiological correlates of the blood oxygen level-dependent (BOLD) signal is necessary to interpret fMRI maps, particularly when obtained in combination with EEG. We review the current understanding of electrophysiological–haemodynamic correlates, during different types of brain activity. We start by describing the basic mechanisms underlying EEG and BOLD signals and proceed by reviewing EEG-informed fMRI studies using fMRI to map specific EEG phenomena over the entire brain (EEG–fMRI mapping), or exploring a range of EEG-derived quantities to determine which best explain colocalised BOLD fluctuations (local EEG–fMRI coupling). While reviewing studies of different forms of brain activity (epileptic and nonepileptic spontaneous activity; cognitive, sensory and motor functions), a significant attention is given to epilepsy because the investigation of its haemodynamic correlates is the most common application of EEG-informed fMRI. Our review is focused on EEG-informed fMRI, an asymmetric approach of data integration. We give special attention to the invasiveness of electrophysiological measurements and the simultaneity of multimodal acquisitions because these methodological aspects determine the nature of the conclusions that can be drawn from EEG-informed fMRI studies. We emphasise the advantages of, and need for, simultaneous intracranial EEG–fMRI studies in humans, which recently became available and hold great potential to improve our understanding of the electrophysiological correlates of BOLD fluctuations. PMID:25277370

Murta, Teresa; Leite, Marco; Carmichael, David W; Figueiredo, Patrícia; Lemieux, Louis

2015-01-01

389

Digital Signal Processing Engine Design for Polar Transmitter in Wireless Communication Systems  

E-print Network

Digital Signal Processing Engine Design for Polar Transmitter in Wireless Communication Systems efficiency Power Amplifier (PA). This paper describes a new design of Digital Signal Processing (DSP) engine process can be precisely controlled by the digital phase modulator. The baseband phase signal is modulated

Hung, Shih-Hao

390

New Solutions for Substation Sensing, Signal Processing and Decision Making M. Kezunovic, Fellow IEEE  

E-print Network

. Introduction The existing substation designs for sensing, signal processing and decision-making have beenNew Solutions for Substation Sensing, Signal Processing and Decision Making M. Kezunovic, Fellow describes a new solution for integrating substation sensing, signal processing and decision making for more

391

Signal Processing Methods for Liquid Rocket Engine Combustion Stability Assessments  

NASA Technical Reports Server (NTRS)

The J2X Gas Generator engine design specifications include dynamic, spontaneous, and broadband combustion stability requirements. These requirements are verified empirically based high frequency chamber pressure measurements and analyses. Dynamic stability is determined with the dynamic pressure response due to an artificial perturbation of the combustion chamber pressure (bomb testing), and spontaneous and broadband stability are determined from the dynamic pressure responses during steady operation starting at specified power levels. J2X Workhorse Gas Generator testing included bomb tests with multiple hardware configurations and operating conditions, including a configuration used explicitly for engine verification test series. This work covers signal processing techniques developed at Marshall Space Flight Center (MSFC) to help assess engine design stability requirements. Dynamic stability assessments were performed following both the CPIA 655 guidelines and a MSFC in-house developed statistical-based approach. The statistical approach was developed to better verify when the dynamic pressure amplitudes corresponding to a particular frequency returned back to pre-bomb characteristics. This was accomplished by first determining the statistical characteristics of the pre-bomb dynamic levels. The pre-bomb statistical characterization provided 95% coverage bounds; these bounds were used as a quantitative measure to determine when the post-bomb signal returned to pre-bomb conditions. The time for post-bomb levels to acceptably return to pre-bomb levels was compared to the dominant frequency-dependent time recommended by CPIA 655. Results for multiple test configurations, including stable and unstable configurations, were reviewed. Spontaneous stability was assessed using two processes: 1) characterization of the ratio of the peak response amplitudes to the excited chamber acoustic mode amplitudes and 2) characterization of the variability of the peak response's frequency over the test duration. This characterization process assists in evaluating the discreteness of a signal as well as the stability of the chamber response. Broadband stability was assessed using a running root-mean-square evaluation. These techniques were also employed, in a comparative analysis, on available Fastrac data, and these results are presented here.

Kenny, R. Jeremy; Lee, Erik; Hulka, James R.; Casiano, Matthew

2011-01-01

392

Single sensor processing to obtain high resolution color component signals  

NASA Technical Reports Server (NTRS)

A method for generating color video signals representative of color images of a scene includes the following steps: focusing light from the scene on an electronic image sensor via a filter having a tri-color filter pattern; producing, from outputs of the sensor, first and second relatively low resolution luminance signals; producing, from outputs of the sensor, a relatively high resolution luminance signal; producing, from a ratio of the relatively high resolution luminance signal to the first relatively low resolution luminance signal, a high band luminance component signal; producing, from outputs of the sensor, relatively low resolution color component signals; and combining each of the relatively low resolution color component signals with the high band luminance component signal to obtain relatively high resolution color component signals.

Glenn, William E. (Inventor)

2010-01-01

393

Regulation of Amyloid Precursor Protein Processing by Serotonin Signaling  

PubMed Central

Proteolytic processing of the amyloid precursor protein (APP) by the ?- and ?-secretases releases the amyloid-? peptide (A?), which deposits in senile plaques and contributes to the etiology of Alzheimer's disease (AD). The ?-secretase cleaves APP in the A? peptide sequence to generate soluble APP? (sAPP?). Upregulation of ?-secretase activity through the 5-hydroxytryptamine 4 (5-HT4) receptor has been shown to reduce A? production, amyloid plaque load and to improve cognitive impairment in transgenic mouse models of AD. Consequently, activation of 5-HT4 receptors following agonist stimulation is considered to be a therapeutic strategy for AD treatment; however, the signaling cascade involved in 5-HT4 receptor-stimulated proteolysis of APP remains to be determined. Here we used chemical and siRNA inhibition to identify the proteins which mediate 5-HT4d receptor-stimulated ?-secretase activity in the SH-SY5Y human neuronal cell line. We show that G protein and Src dependent activation of phospholipase C are required for ?-secretase activity, while, unexpectedly, adenylyl cyclase and cAMP are not involved. Further elucidation of the signaling pathway indicates that inositol triphosphate phosphorylation and casein kinase 2 activation is also a prerequisite for ?-secretase activity. Our findings provide a novel route to explore the treatment of AD through 5-HT4 receptor-induced ?-secretase activation. PMID:24466315

Pimenova, Anna A.; Thathiah, Amantha; De Strooper, Bart; Tesseur, Ina

2014-01-01

394

Temporally selective processing of communication signals by auditory midbrain neurons  

PubMed Central

Perception of the temporal structure of acoustic signals contributes critically to vocal signaling. In the aquatic clawed frog Xenopus laevis, calls differ primarily in the temporal parameter of click rate, which conveys sexual identity and reproductive state. We show here that an ensemble of auditory neurons in the laminar nucleus of the torus semicircularis (TS) of X. laevis specializes in encoding vocalization click rates. We recorded single TS units while pure tones, natural calls, and synthetic clicks were presented directly to the tympanum via a vibration-stimulation probe. Synthesized click rates ranged from 4 to 50 Hz, the rate at which the clicks begin to overlap. Frequency selectivity and temporal processing were characterized using response-intensity curves, temporal-discharge patterns, and autocorrelations of reduplicated responses to click trains. Characteristic frequencies ranged from 140 to 3,250 Hz, with minimum thresholds of ?90 dB re 1 mm/s at 500 Hz and ?76 dB at 1,100 Hz near the dominant frequency of female clicks. Unlike units in the auditory nerve and dorsal medullary nucleus, most toral units respond selectively to the behaviorally relevant temporal feature of the rate of clicks in calls. The majority of neurons (85%) were selective for click rates, and this selectivity remained unchanged over sound levels 10 to 20 dB above threshold. Selective neurons give phasic, tonic, or adapting responses to tone bursts and click trains. Some algorithms that could compute temporally selective receptive fields are described. PMID:21289132

Christensen-Dalsgaard, Jakob; Kelley, Darcy B.

2011-01-01

395

Correlated Gravitational Wave and Neutrino Signals from General-Relativistic Rapidly Rotating Iron Core Collapse  

E-print Network

We present results from a new set of 3D general-relativistic hydrodynamic simulations of rotating iron core collapse. We assume octant symmetry and focus on axisymmetric collapse, bounce, the early postbounce evolution, and the associated gravitational wave (GW) and neutrino signals. We employ a finite-temperature nuclear equation of state, parameterized electron capture in the collapse phase, and a multi-species neutrino leakage scheme after bounce. The latter captures the important effects of deleptonization, neutrino cooling and heating and enables approximate predictions for the neutrino luminosities in the early evolution after core bounce. We consider 12-solar-mass and 40-solar-mass presupernova models and systematically study the effects of (i) rotation, (ii) progenitor structure, and (iii) postbounce neutrino leakage on dynamics, GW, and, neutrino signals. We demonstrate, that the GW signal of rapidly rotating core collapse is practically independent of progenitor mass and precollapse structure. Moreover, we show that the effects of neutrino leakage on the GW signal are strong only in nonrotating or slowly rotating models in which GW emission is not dominated by inner core dynamics. In rapidly rotating cores, core bounce of the centrifugally-deformed inner core excites the fundamental quadrupole pulsation mode of the nascent protoneutron star. The ensuing global oscillations (f~700-800 Hz) lead to pronounced oscillations in the GW signal and correlated strong variations in the rising luminosities of antineutrino and heavy-lepton neutrinos. We find these features in cores that collapse to protoneutron stars with spin periods <~ 2.5 ms and rotational energies sufficient to drive hyper-energetic core-collapse supernova explosions. Hence, joint GW + neutrino observations of a core collapse event could deliver strong evidence for or against rapid core rotation. [abridged

C. D. Ott; E. Abdikamalov; E. O'Connor; C. Reisswig; R. Haas; P. Kalmus; S. Drasco; A. Burrows; E. Schnetter

2013-03-25

396

A joint signal processing and cryptographic approach to multimedia encryption.  

PubMed

In recent years, there has been an increasing trend for multimedia applications to use delegate service providers for content distribution, archiving, search, and retrieval. These delegate services have brought new challenges to the protection of multimedia content confidentiality. This paper discusses the importance and feasibility of applying a joint signal processing and cryptographic approach to multimedia encryption, in order to address the access control issues unique to multimedia applications. We propose two atomic encryption operations that can preserve standard compliance and are friendly to delegate processing. Quantitative analysis for these operations is presented to demonstrate that a good tradeoff can be made between security and bitrate overhead. In assisting the design and evaluation of media security systems, we also propose a set of multimedia-oriented security scores to quantify the security against approximation attacks and to complement the existing notion of generic data security. Using video as an example, we present a systematic study on how to strategically integrate different atomic operations to build a video encryption system. The resulting system can provide superior performance over both generic encryption and its simple adaptation to video in terms of a joint consideration of security, bitrate overhead, and friendliness to delegate processing. PMID:16830924

Mao, Yinian; Wu, Min

2006-07-01

397

Denoising of Ultrasonic Signals Backscattered from Coarse-Grained Materials: Wavelet Processing and Maximum-Entropy Reconstruction  

NASA Astrophysics Data System (ADS)

Ultrasonic inspection of coarse-grained metal structures (e.g., certain types of nuclear reactor piping and railroad sections) is seriously compromised by the large size of the anisotropic grains relative to the wavelength of the acoustic pulse. Genuine flaw signals are masked by false signals and signal clutter due to reflection and scattering of the sound beam at grain boundaries. This difficult denoising problem was initially addressed by applying some recent theoretical ideas [1] concerning level-dependent wavelet thresholding in the presence of correlated noise. Modest but measurable improvements were achieved using these wavelet-processing algorithms. However, much more dramatic success was realized with the approach of maximum-entropy reconstruction [2] using an adjustable noise-removal parameter and point-spread function. REFERENCES: [1] Johnstone and Silverman, J. Roy. Statistical Soc. B59, 319 (1997); Jansen et al., Signal Processing 56, 33 (1997). [2] Skilling and Bryan, Monthly Notices Roy. Astron. Soc. 211, 111 (1984).

Johnston, Shayne; Diaz, Aaron; Doctor, Steven

2000-11-01

398

Neurological Tremor: Sensors, Signal Processing and Emerging Applications  

PubMed Central

Neurological tremor is the most common movement disorder, affecting more than 4% of elderly people. Tremor is a non linear and non stationary phenomenon, which is increasingly recognized. The issue of selection of sensors is central in the characterization of tremor. This paper reviews the state-of-the-art instrumentation and methods of signal processing for tremor occurring in humans. We describe the advantages and disadvantages of the most commonly used sensors, as well as the emerging wearable sensors being developed to assess tremor instantaneously. We discuss the current limitations and the future applications such as the integration of tremor sensors in BCIs (brain-computer interfaces) and the need for sensor fusion approaches for wearable solutions. PMID:22205874

Grimaldi, Giuliana; Manto, Mario

2010-01-01

399

A new signal processing platform for radio astronomy  

NASA Astrophysics Data System (ADS)

Context: We describe the concept, construction, and testing of TasPGA, a new, versatile digital signal processing device designed for radio astronomy applications. Aims: A minimalist design philosophy was used to develop a general-purpose radio astronomy instrument based on field programmable gate array (FPGA) technology. The design emphasises reliability and flexibility, facilitating the rapid development of new FPGA firmware for a wide range of experiments. Methods: Hardware and firmware for TasPGA were designed using software provided by Altium Ltd. and Xilinx Inc. We tested the instrument by implementing a Fourier transform spectrometer capable of dividing 100 MHz of bandwidth into 16 384 channels. Results: We present data taken with a TasPGA spectrometer at the Mt. Pleasant radio observatory, including the spectra of two astronomical methanol masers.

Hotan, A. W.

2008-07-01

400

Information processing by tree fellers: signal detection analysis.  

PubMed

Eighteen experienced tree fellers and eighteen forestry students watched video recordings of mature eucalypts being felled by a man using a chain saw, and then rated whether each tree had fallen normally or abnormally. Signal-detection analysis showed that the tree fellers were more accurate than the forestry students in predicting eventual outcome. Further, the tree fellers achieved peak accuracy in discrimination by the time the logger had completed cutting the scarf (typically several minutes before the tree hit the ground), whereas the forestry students predicted outcome most accurately only when a tree was falling (and about 1 s from hitting the ground). Study of the bases for information processing and decision making by tree fellers has implications for personnel selection and training, as well as for formulation of effective work practices. PMID:8041591

Henderson, M; Over, R

1993-01-01

401

Correlations of Melt Pool Geometry and Process Parameters During Laser Metal Deposition by Coaxial Process Monitoring  

NASA Astrophysics Data System (ADS)

One major demand of today's laser metal deposition (LMD) processes is to achieve a fail-save build-up regarding changing conditions like heat accumulations. Especially for the repair of thin parts like turbine blades is the knowledge about the correlations between melt pool behavior and process parameters like laser power, feed rate and powder mass stream indispensable. The paper will show the process layout with the camera based coaxial monitoring system and the quantitative influence of the process parameters on the melt pool geometry. Therefore the diameter, length and area of the melt pool are measured by a video analytic system at various parameters and compared with the track wide in cross-sections and the laser spot diameter. The influence of changing process conditions on the melt pool is also investigated. On the base of these results an enhanced process of the build-up of a multilayer one track fillet geometry will be presented.

Ocylok, Sörn; Alexeev, Eugen; Mann, Stefan; Weisheit, Andreas; Wissenbach, Konrad; Kelbassa, Ingomar

402

Digital Signal Processing System for Active Noise Reduction  

NASA Astrophysics Data System (ADS)

Over the years there has been a need to improve the comfort of passengers in flight. One avenue for increasing comfort is to reduce cabin noise that is attributed to the engine and the vibration of fuselage panels that radiate sound. High frequency noise can be abated using sound absorbing material. Though, for low frequency noise the sound absorption material would have to very thick, thereby reducing the cabin size. To reduce these low frequency disturbances, active noise control systems (ANC) is being developed that utilizes feedback for cancellation of the disturbance. The active noise control system must be small in size, be a low power device, and operate in real-time. It must also be numerically stable i.e. insensitive to temperature and pressure variations. The ANC system will be a module that consists of digital signal processor (DSP), analog-digital and digital-analog converters, power converters, an actuator and sensors. The DSP will implement the feedback control algorithm that controls the actuators. This module will be attached to panels on the inside of the fuselage for actively eliminating resonant modes of the structure caused by turbulent flow across the fuselage Skin. A hardware prototype of the ANC system must be able to eliminate broadband noise consisting of a bandwidth between 100 Hz and 1500 Hz, which requires a sample rate of 5000 Hz. The analog/digital converters output accuracy is 16 bits with a 2's-compliment format and a very short acquisition time. This will also yield the appropriate dynamic range. Similar specifications are required of the digital/analog converter. The processor section of the system integrates a digital signal processor (TI TMS320C33) with analog/digital (Burr-Brown ADS8320) and digital/analog signal (DAC853 1) converters. The converters with associated power conditioning circuitry and test points reside on a daughter board that sits on top of a Spectrum Digital evaluation module. This will have the ability to test different adaptive noise cancellation algorithms and provide an operational prototype to understand the behavior of the system under test. DSP software was required to interface the processor with the data converters using interrupt routines. The goal is to build a complete ANC system that can be placed on a flexible circuit with added memory circuitry that also contains the power supply, sensors and actuators. This work on the digital signal processing system for active noise reduction was completed in collaboration with another ASEE Fellow, Dr. Jerry Tucker from Virginia Commonwealth University, Richmond, VA.

Edmonson, William W.; Tucker, Jerry

2002-12-01

403

Quantum correlation dynamics in photosynthetic processes assisted by molecular vibrations  

E-print Network

During the long course of evolution, nature has learnt how to exploit quantum effects. In fact, recent experiments reveal the existence of quantum processes whose coherence extends over unexpectedly long time and space ranges. In particular, photosynthetic processes in light-harvesting complexes display a typical oscillatory dynamics ascribed to quantum coherence. Here, we consider the simple model where a dimer made of two chromophores is strongly coupled with a quasi-resonant vibrational mode. We observe the occurrence of wide oscillations of genuine quantum correlations, between electronic excitations and the environment, represented by vibrational bosonic modes. Such a quantum dynamics has been unveiled through the calculation of the negativity of entanglement and the discord, indicators widely used in quantum information for quantifying the resources needed to realize quantum technologies. We also discuss the possibility of approximating additional weakly-coupled off-resonant vibrational modes, simulating the disturbances induced by the rest of the environment, by a single vibrational mode. Within this approximation, one can show that the off-resonant bath behaves like a classical source of noise.

G. L. Giorgi; M. Roncaglia; F. A. Raffa; M. Genovese

2015-01-30

404

Signal processing approaches to radio frequency interference (RFI) suppression  

NASA Astrophysics Data System (ADS)

Ultra-wideband radar (UWB) has been shown to be among the most powerful techniques available for underground and obscured object detection. The value of such systems is that they combine the penetration enhancement associated with VHF/UHF (and lower) frequencies with the resolution of wide absolute bandwidth. Such systems necessarily make use of much of the frequency spectrum already in heavy use by other services, such as television and mobile communications. Although this spectral overlap provides occasion for adverse consequences in both directions, to date the principal consequence has been often-severe impact on UWB radar measurements. Even in remote locations, the average interference power often exceeds receiver noise by many dB, becoming the limiting factor on system sensitivity. Nor are UWB radar designers free to overcome this interference by increasing radar power, since regulatory sanction for UWB operation will depend on maintaining sufficiently low spectral power densities to assure that other, prior, services are not appreciably degraded. Given the importance of radio frequency interference (RFI) on practical ultrawide band ground penetrating radar systems, it is important to consider how and to what extent the effects of RFI noise may be reduced. The overall problem of RFI and its impacts will be described and several signal processing approaches to removal of RFI will be discussed. These include spectral estimation and coherent subtraction algorithms and various filter approaches, which have been developed and applied by the signal processing community in other contexts. These methods will be applied to several different real-world experimental data sets, and quantitative measures of the effectiveness of each of these algorithms in removing RFI noise will be presented. Although computationally-intensive, most of the techniques to be described achieve substantial increases in S/RFI without requiring concomitant increases in radar average power.

Braunstein, Matthew; Ralston, James M.; Sparrow, David A.

1994-06-01

405

Numerical evaluation of correlation between crack size and eddy current testing signal by a very fast simulator  

Microsoft Academic Search

This paper describes work on the development of a very fast eddy current testing (ECT) signal simulator, and its application to the evaluation of the correlation between cracks and signals. This simulator is developed here based on a reduced magnetic vector potential, edge based finite elements, and the pre-computed unflawed database approach. Using this simulator, three kinds of probes are

Toshiyuki Takagi; Haoyu Huang; Hiroyuki Fukutomi; Junji Tani

1998-01-01

406

A nonlinear optoelectronic filter for electronic signal processing  

PubMed Central

The conversion of electrical signals into modulated optical waves and back into electrical signals provides the capacity for low-loss radio-frequency (RF) signal transfer over optical fiber. Here, we show that the unique properties of this microwave-photonic link also enable the manipulation of RF signals beyond what is possible in conventional systems. We achieve these capabilities by realizing a novel nonlinear filter, which acts to suppress a stronger RF signal in the presence of a weaker signal independent of their separation in frequency. Using this filter, we demonstrate a relative suppression of 56?dB for a stronger signal having a 1-GHz center frequency, uncovering the presence of otherwise undetectable weaker signals located as close as 3.5?Hz away. The capabilities of the optoelectronic filter break the conventional limits of signal detection, opening up new possibilities for radar and communication systems, and for the field of precision frequency metrology. PMID:24402418

Loh, William; Yegnanarayanan, Siva; Ram, Rajeev J.; Juodawlkis, Paul W.

2014-01-01

407

Laser-induced breakdown spectroscopy in water: Improvement of the detection threshold by signal processing  

NASA Astrophysics Data System (ADS)

Laser-induced breakdown spectroscopy (LIBS) has been performed on immersed solid samples with different grades of surface roughness and material homogeneity and on bulk water solutions. The underwater plasma was produced by applying double-pulse excitation at 1064 nm, with different sets of laser pulse energies. LIBS spectra were recorded separately for each couple of laser pulses in order to monitor shot-to-shot plasma behavior and to apply signal post processing. The latter was aimed at improving the detection limits for elemental analyses. Except in the case of flat homogeneous solid samples at high laser pulse energies, the measurements were affected by strong shot-to-shot signal oscillations. Automatic elimination of low intensity spectra reduced the detection limit up to a factor of seven. The optimum level for spectral filtering depends strongly on sample properties. For bulk water, a poor correlation was observed between the peak line intensities and the plasma continuum emission, making the peak-to-background ratio unsuitable for internal standardization purposes. The analytical performance of LIBS for bulk liquid was also affected by the spatial fluctuations of the breakdown location, a phenomenon known as "moving breakdown" in the literature, which was responsible for the signal depletion in the detection region. In preliminary measurements on water solutions, the detection limit of 0.2 mg/l for magnesium has been obtained after applying data post processing.

Lazic, V.; Colao, F.; Fantoni, R.; Spizzicchino, V.

2005-08-01

408

Signal-to-noise ratio requirements for detection of multiple pulses subject to partially correlated fading with chi-squared statistics of various degrees of freedom  

NASA Astrophysics Data System (ADS)

The transmitted signal in a fading medium is composed of several pulses separated in time so as to achieve diversity and thereby combat deep fades and loss of signal. Receiver processing consists of matched filtering of each of the pulses, followed by summation of the squared envelopes of all the filter outputs. In addition to additive Gaussian background noise, the signal is subject to slow medium fading which has a chi-squared first-order distribution and which may be correlated from pulse to pulse to an arbitrary degree. The false alarm and detection probabilities of this system are derived in various series expansions which are amenable to efficient computer evaluation. Programs are presented and exercised for various combinations of signal-to-noise ratio, number of pulses, degree of correlated fading, and (noninteger) number of degrees of freedom of the chi-squared fading. Required input signal-to-noise ratios for several false alarm and detection probabilities are computed and plotted for cases of the fading normalized correlation coefficient ranging from 0 to 1; results for a nonfading medium are superposed for easy comparison. Special cases are dependent and independent Rayleigh amplitude fading.

Nuttall, Albert H.; Eby, Edward S.

1986-06-01

409

ECEN 444-501: Digital Signal Processing, Fall `12 Review #1 Review (midterm exam #1)  

E-print Network

ECEN 444-501: Digital Signal Processing, Fall `12 Review #1 Review (midterm exam #1) Signals & Systems · periodic vs. aperiodic signals · linearity · time-invariance · static vs. dynamic systems - 2], u[n] - u[n - 4]. · Sifting property: x[n][n], x[n][n - no], etc. · Representation of a signal

Yoon, Byung-Jun

410

Differential auditory signal processing in an animal model  

NASA Astrophysics Data System (ADS)

Auditory evoked responses were collected in male zebra finches (Poephila guttata) to objectively determine differential frequency selectivity. First, the mating call of the animal was recorded and analyzed for its frequency components through the customized program. Then, auditory brainstem responses and cortical responses of each anesthetized animal were routinely recorded in response to tone bursts of 1-8 kHz derived from the corresponding mating call spectrum. From the results, most mating calls showed relatively consistent spectral structures. The upper limit of the spectrum was well under 10 kHz. The peak energy bands were concentrated in the region less than 5 kHz. The assessment of auditory brainstem responses and cortical evoked potentials showed differential selectivity with a series of characteristic scales. This system appears to be an excellent model to investigate complex sound processing and related language behaviors. These data could also be used in designing effective signal processing strategies in auditory rehabilitation devices such as hearing aids and cochlear implants. [Work supported by Brain Science & Engineering Program from Korean Ministry of Science and Technology.

Lim, Dukhwan; Kim, Chongsun; Chang, Sun O.

2002-05-01

411

Optimal Signal Processing of Frequency-Stepped CW Radar Data  

NASA Technical Reports Server (NTRS)

An optimal signal processing algorithm is derived for estimating the time delay and amplitude of each scatterer reflection using a frequency-stepped CW system. The channel is assumed to be composed of abrupt changes in the reflection coefficient profile. The optimization technique is intended to maximize the target range resolution achievable from any set of frequency-stepped CW radar measurements made in such an environment. The algorithm is composed of an iterative two-step procedure. First, the amplitudes of the echoes are optimized by solving an overdetermined least squares set of equations. Then, a nonlinear objective function is scanned in an organized fashion to find its global minimum. The result is a set of echo strengths and time delay estimates. Although this paper addresses the specific problem of resolving the time delay between the two echoes, the derivation is general in the number of echoes. Performance of the optimization approach is illustrated using measured data obtained from an HP-851O network analyzer. It is demonstrated that the optimization approach offers a significant resolution enhancement over the standard processing approach that employs an IFFT. Degradation in the performance of the algorithm due to suboptimal model order selection and the effects of additive white Gaussion noise are addressed.

Ybarra, Gary A.; Wu, Shawkang M.; Bilbro, Griff L.; Ardalan, Sasan H.; Hearn, Chase P.; Neece, Robert T.

1995-01-01

412

Correlative intravital imaging of cGMP signals and vasodilation in mice  

PubMed Central

Cyclic guanosine monophosphate (cGMP) is an important signaling molecule and drug target in the cardiovascular system. It is well known that stimulation of the vascular nitric oxide (NO)-cGMP pathway results in vasodilation. However, the spatiotemporal dynamics of cGMP signals themselves and the cGMP concentrations within specific cardiovascular cell types in health, disease, and during pharmacotherapy with cGMP-elevating drugs are largely unknown. To facilitate the analysis of cGMP signaling in vivo, we have generated transgenic mice that express fluorescence resonance energy transfer (FRET)-based cGMP sensor proteins. Here, we describe two models of intravital FRET/cGMP imaging in the vasculature of cGMP sensor mice: (1) epifluorescence-based ratio imaging in resistance-type vessels of the cremaster muscle and (2) ratio imaging by multiphoton microscopy within the walls of subcutaneous blood vessels accessed through a dorsal skinfold chamber. Both methods allow simultaneous monitoring of NO-induced cGMP transients and vasodilation in living mice. Detailed protocols of all steps necessary to perform and evaluate intravital imaging experiments of the vasculature of anesthetized mice including surgery, imaging, and data evaluation are provided. An image segmentation approach is described to estimate FRET/cGMP changes within moving structures such as the vessel wall during vasodilation. The methods presented herein should be useful to visualize cGMP or other biochemical signals that are detectable with FRET-based biosensors, such as cyclic adenosine monophosphate or Ca2+, and to correlate them with respective vascular responses. With further refinement and combination of transgenic mouse models and intravital imaging technologies, we envision an exciting future, in which we are able to “watch” biochemistry, (patho-)physiology, and pharmacotherapy in the context of a living mammalian organism. PMID:25352809

Thunemann, Martin; Schmidt, Kjestine; de Wit, Cor; Han, Xiaoxing; Jain, Rakesh K.; Fukumura, Dai; Feil, Robert

2014-01-01

413

Clay content evaluation in soils through GPR signal processing  

NASA Astrophysics Data System (ADS)

The mechanical behavior of soils is partly affected by their clay content, which arises some important issues in many fields of employment, such as civil and environmental engineering, geology, and agriculture. This work focuses on pavement engineering, although the method applies to other fields of interest. Clay content in bearing courses of road pavement frequently causes damages and defects (e.g., cracks, deformations, and ruts). Therefore, the road safety and operability decreases, directly affecting the increase of expected accidents. In this study, different ground-penetrating radar (GPR) methods and techniques were used to non-destructively investigate the clay content in sub-asphalt compacted soils. Experimental layout provided the use of typical road materials, employed for road bearing courses construction. Three types of soils classified by the American Association of State Highway and Transportation Officials (AASHTO) as A1, A2, and A3 were used and adequately compacted in electrically and hydraulically isolated test boxes. Percentages of bentonite clay were gradually added, ranging from 2% to 25% by weight. Analyses were carried out for each clay content using two different GPR instruments. A pulse radar with ground-coupled antennae at 500 MHz centre frequency and a vector network analyzer spanning the 1-3 GHz frequency range were used. Signals were processed in both time and frequency domains, and the consistency of results was validated by the Rayleigh scattering method, the full-waveform inversion, and the signal picking techniques. Promising results were obtained for the detection of clay content affecting the bearing capacity of sub-asphalt layers.

Tosti, Fabio; Patriarca, Claudio; Slob, Evert; Benedetto, Andrea; Lambot, Sébastien

2013-10-01

414

IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 55, NO. 8, AUGUST 2007 4151 On Probing Signal Design For MIMO Radar  

E-print Network

For MIMO Radar Petre Stoica, Fellow, IEEE, Jian Li, Fellow, IEEE, and Yao Xie, Student Member, IEEE Abstract--A multiple-input multiple-output (MIMO) radar system, unlike a standard phased-array radar, can the cross-correlation of the signals reflected back to the radar by the targets of interest. In this paper

Xie, Yao

415

PROCESSING OF SONAR SIGNALS USING NEURAL NETWORKS FOR ROBUST TARGET DIFFERENTIATION  

E-print Network

PROCESSING OF SONAR SIGNALS USING NEURAL NETWORKS FOR ROBUST TARGET DIFFERENTIATION Birsel Ayrulu ABSTRACT This study investigates the processing of sonar signals using neural networks for robust di is of interest for intel- ligent systems. Amplitude and time-of- ight TOF patterns of sonar signals acquired from

Barshan, Billur

416

Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process  

E-print Network

Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process algebra Regulated Kinase (ERK) signalling pathway [5] through modelling in a Markovian process algebra, PEPA [11 durations and probabilistic choices. The system which we consider is the Ras/Raf-1/MEK/ERK signalling

Calder, Muffy

417

A Kind of Signal Processing Method for the Polarization Phased Array Radar  

Microsoft Academic Search

This paper discusses a kind of polarization phased array radar system and its signal processing method. The polarization signal processing technology is introduced to improve the detection performance and anti-jamming ability of the radars. In order to achieve the performance of low probability of intercept (LPI) for the transmitted signal, the linear frequency modulation (LFM) is adopted inside each pulse

Song Li-zhong; Qiao Xiao-lin; Fu Shi-feng; Wu Qun

2009-01-01

418

Correlations between the Signal Complexity of Cerebral and Cardiac Electrical Activity: A Multiscale Entropy Analysis  

PubMed Central

The heart begins to beat before the brain is formed. Whether conventional hierarchical central commands sent by the brain to the heart alone explain all the interplay between these two organs should be reconsidered. Here, we demonstrate correlations between the signal complexity of brain and cardiac activity. Eighty-seven geriatric outpatients with healthy hearts and varied cognitive abilities each provided a 24-hour electrocardiography (ECG) and a 19-channel eye-closed routine electroencephalography (EEG). Multiscale entropy (MSE) analysis was applied to three epochs (resting-awake state, photic stimulation of fast frequencies (fast-PS), and photic stimulation of slow frequencies (slow-PS)) of EEG in the 1–58 Hz frequency range, and three RR interval (RRI) time series (awake-state, sleep and that concomitant with the EEG) for each subject. The low-to-high frequency power (LF/HF) ratio of RRI was calculated to represent sympatho-vagal balance. With statistics after Bonferroni corrections, we found that: (a) the summed MSE value on coarse scales of the awake RRI (scales 11–20, RRI-MSE-coarse) were inversely correlated with the summed MSE value on coarse scales of the resting-awake EEG (scales 6–20, EEG-MSE-coarse) at Fp2, C4, T6 and T4; (b) the awake RRI-MSE-coarse was inversely correlated with the fast-PS EEG-MSE-coarse at O1, O2 and C4; (c) the sleep RRI-MSE-coarse was inversely correlated with the slow-PS EEG-MSE-coarse at Fp2; (d) the RRI-MSE-coarse and LF/HF ratio of the awake RRI were correlated positively to each other; (e) the EEG-MSE-coarse at F8 was proportional to the cognitive test score; (f) the results conform to the cholinergic hypothesis which states that cognitive impairment causes reduction in vagal cardiac modulation; (g) fast-PS significantly lowered the EEG-MSE-coarse globally. Whether these heart-brain correlations could be fully explained by the central autonomic network is unknown and needs further exploration. PMID:24498375

Lin, Pei-Feng; Lo, Men-Tzung; Tsao, Jenho; Chang, Yi-Chung; Lin, Chen; Ho, Yi-Lwun

2014-01-01

419

Monitoring and predicting cognitive state and performance via physiological correlates of neuronal signals.  

PubMed

Judgment, decision making, and situational awareness are higher-order mental abilities critically important to operational cognitive performance. Higher-order mental abilities rely on intact functioning of multiple brain regions, including the prefrontal, thalamus, and parietal areas. Real-time monitoring of individuals for cognitive performance capacity via an approach based on sampling multiple neurophysiologic signals and integrating those signals with performance prediction models potentially provides a method of supporting warfighters' and commanders' decision making and other operationally relevant mental processes and is consistent with the goals of augmented cognition. Cognitive neurophysiological assessments that directly measure brain function and subsequent cognition include positron emission tomography, functional magnetic resonance imaging, mass spectroscopy, near-infrared spectroscopy, magnetoencephalography, and electroencephalography (EEG); however, most direct measures are not practical to use in operational environments. More practical, albeit indirect measures that are generated by, but removed from the actual neural sources, are movement activity, oculometrics, heart rate, and voice stress signals. The goal of the papers in this section is to describe advances in selected direct and indirect cognitive neurophysiologic monitoring techniques as applied for the ultimate purpose of preventing operational performance failures. These papers present data acquired in a wide variety of environments, including laboratory, simulator, and clinical arenas. The papers discuss cognitive neurophysiologic measures such as digital signal processing wrist-mounted actigraphy; oculometrics including blinks, saccadic eye movements, pupillary movements, the pupil light reflex; and high-frequency EEG. These neurophysiological indices are related to cognitive performance as measured through standard test batteries and simulators with conditions including sleep loss, time on task, and aviation flight-induced fatigue. PMID:16018331

Russo, Michael B; Stetz, Melba C; Thomas, Maria L

2005-07-01

420

[Analysis of sleep electroencephalograph signal based on detrended cross-correlation].  

PubMed

The quality of sleep has a great relationship with health and working efficiency. The result of sleep stage classification is an important indicator to measure the quality of sleep, and it is also an important way to diagnose and treat sleep disorders. In this paper, the method of detrended cross-correlation analysis (DCCA) was used to analyze sleep stage classification, sleep electroencephalograph signals, which were extracted from the MIT-BIH Polysomno graphic Database randomly. The results showed that the average DCCA exponent of the awake period is smaller than that of the first stage of non-rapid eye movement (NREM) sleeps. It is well concluded that the method of studying the sleep electroencephalograph with this method is of great significance to improve the quality of sleep, to diagnose and to treat sleep disorders. PMID:24804482

Wang, Yulan; Wang, Jun

2014-02-01

421

Programmable rate modem utilizing digital signal processing techniques  

NASA Technical Reports Server (NTRS)

The engineering development study to follow was written to address the need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) modulation. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. Here design tradeoffs in each portion of the modulator and demodulator subsystem are outlined, and viable circuit approaches which are easily repeatable, have low implementation losses and have low production costs are identified. The research involved for this study was divided into nine technical papers, each addressing a significant region of concern in a variable rate modem design. Trivial portions and basic support logic designs surrounding the nine major modem blocks were omitted. In brief, the nine topic areas were: (1) Transmit Data Filtering; (2) Transmit Clock Generation; (3) Carrier Synthesizer; (4) Receive AGC; (5) Receive Data Filtering; (6) RF Oscillator Phase Noise; (7) Receive Carrier Selectivity; (8) Carrier Recovery; and (9) Timing Recovery.

Bunya, George K.; Wallace, Robert L.

1989-01-01

422

Research on the signal processing technology of laser fuze  

NASA Astrophysics Data System (ADS)

Laser fuze has been widely used in a variety of large-caliber ammunitions, such as missile, aerial bomb and rocket bomb, due to its typical advantages of proactivity in target detection, sharp directivity of probe field and strong antielectromagnetic interference ability. Recently a new kind of small laser fuze adapted to small-caliber ammunitions is being actively developed. Designed the mathematic model of the laser echo waveform based on Gauss beam and deduced time domain of echo impulse power with varied sharps of target (such as plane target, circle target and mutant target). Echo impulse waveform of laser fuse with the noise interference, such as sunlight and raindrop, also has been studied based on the modeling. The test experiments show that the system can detect weak laser echoed wave, distinguish target and interferences signal by amplifying, modulating and processing the echoed waveform, and detect vertical test board (gray iron) at 5m far away with no more than 90mA current. The test results in High overload conditions indicates that the prototyping can work normally and steadily in the whole trajectory.

Gao, Jing; Deng, Jiahao; Cai, Kerong

2011-06-01

423

Circular-Birefringence Fiber for Nonlinear Optical Signal Processing  

NASA Astrophysics Data System (ADS)

The circular-birefringence fiber (CBF) or the so-called twisted fiber provides novel attractive potential for all-optical signal-processing applications. Unlike a standard nonpolarization-maintaining (non-PM) fiber, where the polarization dependence of ?3 nonlinearity is averaged out by the residual birefringence, the CBF behaves as a perfectly isotropic fiber in terms of nonlinear wave propagation. The CBF, therefore, allows the utilization of the intrinsic absolute polarization dependence of ?3 nonlinearity in realizing novel functions that can never be obtained with a non-PM fiber. Several types of CBF are successfully fabricated by twisting commercial non-PM fibers at 15 turns/m, and their unique potential is experimentally demonstrated. First, a novel type of all-optical intensity discriminator is realized using the effect of ellipse rotation in CBF, which is absent in a non-PM fiber. The demonstrated device is directly applicable to all-optical data reshaping, pulse compression, pedestral suppression, and enhanced mode-locking of fiber lasers. Next, a 160-Gb/s polarization-insensitive wavelength conversion is demonstrated by using cross-phase modulation in CBF with a circularly polarized probe wave. In addition to its simplicity and robustness, the scheme is readily upgradable to polarization-insensitive all-optical data regeneration.

Tanemura, Takuo; Kikuchi, Kazuro

2006-11-01

424

Cryogenic loss monitors with FPGA TDC signal processing  

SciTech Connect

Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highlight the processing techniques used.

Warner, A.; Wu, J.; /Fermilab

2011-09-01

425

Stream Correlation Monitoring for Uncertainty-Aware Data Processing Systems  

E-print Network

an uncertainty-aware data management system capable of monitoring pairwise correlations of large sensor data correlation monitoring, uncertainty quantification, wireless sensor networks I. INTRODUCTION During the last streams from distinct sensors. For instance, temperature and pressure sensors, which monitor an industrial

Tsakalides, Panagiotis

426

Detection and Processing Techniques of FECG Signal for Fetal Monitoring  

PubMed Central

Fetal electrocardiogram (FECG) signal contains potentially precise information that could assist clinicians in making more appropriate and timely decisions during labor. The ultimate reason for the interest in FECG signal analysis is in clinical diagnosis and biomedical applications. The extraction and detection of the FECG signal from composite abdominal signals with powerful and advance methodologies are becoming very important requirements in fetal monitoring. The purpose of this review paper is to illustrate the various methodologies and developed algorithms on FECG signal detection and analysis to provide efficient and effective ways of understanding the FECG signal and its nature for fetal monitoring. A comparative study has been carried out to show the performance and accuracy of various methods of FECG signal analysis for fetal monitoring. Finally, this paper further focused some of the hardware implementations using electrical signals for monitoring the fetal heart rate. This paper opens up a passage for researchers, physicians, and end users to advocate an excellent understanding of FECG signal and its analysis procedures for fetal heart rate monitoring system. PMID:19495912

2009-01-01

427

Signal Processing by Generalized Receiver in DS-CDMA Wireless Communication Systems with Frequency-Selective Channels  

Microsoft Academic Search

The generalized receiver (GR) based on a generalized approach to signal processing (GASP) in noise is investigated in a direct-sequence\\u000a code-division multiple access (DS-CDMA) wireless communication system with frequency-selective channels. We consider four\\u000a avenues: linear equalization with finite impulse response (FIR) beamforming filters; channel estimation and spatially correlation;\\u000a optimal combining; and partial cancellation. We investigate the GR with simple linear

Vyacheslav Tuzlukov

428

Signal processing and statistical descriptive reanalysis of steady state chute-flow experiments  

NASA Astrophysics Data System (ADS)

An accurate knowledge of snow rheology is needed for the mitigation against avalanche hazard. Indeed snow avalanches have a significant impact on the livelihoods and economies of alpine communities. To do so, 60 small-scale in-situ flow experiments were performed with various slopes, temperatures and flow depths. The investigation of these data previously seemed to show the dense flow of dry snow may be composed of two layers; a sheared basal layer made of single snow grains and a less sheared upper layer made of large aggregates. These outcomes were mainly based on the mean velocity profile of the flow and on interpretation in terms of rheological behavior of granular materials and snow microstructure [Pierre G. Rognon et al., 2007]. Here, the main objective remains the same, but the rheological and physical viewpoints are put aside to extract as much information contained in the data as possible various using signal processing methods and descriptive statistics methods as the maximum overlap discrete wavelet transform (MODWT), transfer entropy (TE) and maximum cross-correlation (MCC). Specifically, we aim at the improving the velocity estimations as function of the depth particularly the velocity fluctuations around the mean profile to better document the behavior of dense dry snow flows during a steady and uniform chute regime. The data are composed of pairs of voltage signals (right and left), which makes that the velocity is known indirectly only. The MCC method is classically used to determine the time lag between both signals. Previously, the MCC method that showed the mean velocity profile may be fitted by a simple bilinear function [Pierre G. Rognon et al., 2007], but no interesting temporal dynamics could be highlighted. Hence, a new process method was developed to provide velocity series with much better temporal resolution. The process is mainly made of a MODWT-based denoising method and the choice of window size for correlation. The results prove to be good enough in term of reasonable variability and measurement numbers. A statistical descriptive analysis of the velocity results shows a disagreement with the previous outcomes. Indeed, the clustering method and the empirical probability distribution functions show that the vertical velocity profile may reflect three different behaviors, possibly corresponding to three layers and/or to transient flow layers. These flow layers are located at different heights depending on initial conditions of flow experiments (temperature, slope and depth). Keywords: Maximum cross correlation, MODWT, probability distribution function

truong, hoan; eckert, nicolas; keylock, chris; naaim, mohamed; bellot, hervé

2014-05-01

429

Signal Processor Development by Personnel of the JSC Signal Processing Section  

NASA Technical Reports Server (NTRS)

The purpose of this paper is to describe systems and components of systems developed by personnel in the Signal Processing Section of the Tracking and Communications Division. The scope of this includes past developments which are in current use in NASA flight operations and future developments which are targeted for upcoming NASA applications. These projects specifically are: (1) NASA High Definition Television (HDTV) Project, (2) Video Codecs, (3) NASA Electronic Still Camera (ESC) Project, (4) Hercules Payload, (5) Ku-band Communications Adapter (KCA), (6) Windows Drivers for Satellite Interfacing to Commercial Equipment, and (7) Advanced Statistical Multiplexers. The methods used to determine what projects should be done in-house as opposed to which should not is based in NASA applications versus commercially available systems to meet those applications. If a commercial-off-the-shelf (COTS) component or system is available which meets the need, the first choice is to use COTS equipment. If it is not, and there is a NASA requirement, it is developed in-house. This results in technology which is being developed which otherwise was not available. Personnel involved in these projects have been contacted by many commercial companies interested in licensing or obtaining the NASA design.

Holland, S. Douglas

1994-01-01

430

Digital Signal Processing Techniques for the GIFTS SM EDU  

NASA Technical Reports Server (NTRS)

The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument employs three Focal Plane Arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes several digital signal processing (DSP) techniques involved in the development of the calibration model. In the first stage, the measured raw interferograms must undergo a series of processing steps that include filtering, decimation, and detector nonlinearity correction. The digital filtering is achieved by employing a linear-phase even-length FIR complex filter that is designed based on the optimum equiripple criteria. Next, the detector nonlinearity effect is compensated for using a set of pre-determined detector response characteristics. In the next stage, a phase correction algorithm is applied to the decimated interferograms. This is accomplished by first estimating the phase function from the spectral phase response of the windowed interferogram, and then correcting the entire interferogram based on the estimated phase function. In the calibration stage, we first compute the spectral responsivity based on the previous results and the ideal Planck blackbody spectra at the given temperatures, from which, the calibrated ambient blackbody (ABB), hot blackbody (HBB), and scene spectra can be obtained. In the post-calibration stage, we estimate the Noise Equivalent Spectral Radiance (NESR) from the calibrated ABB and HBB spectra. The NESR is generally considered as a measure of the instrument noise performance, and can be estimated as the standard deviation of calibrated radiance spectra from multiple scans. To obtain an estimate of the FPA performance, we developed an efficient method of generating pixel performance assessments. In addition, a random pixel selection scheme is developed based on the pixel performance evaluation. This would allow us to perform the calibration procedures on a random pixel population that is a good statistical representation of the entire FPA. The design and implementation of each individual component will be discussed in details.

Tian, Jialin; Reisse, Robert A.; Gazarik, Michael J.

2007-01-01

431

Statistical tests for power-law cross-correlated processes  

NASA Astrophysics Data System (ADS)

For stationary time series, the cross-covariance and the cross-correlation as functions of time lag n serve to quantify the similarity of two time series. The latter measure is also used to assess whether the cross-correlations are statistically significant. For nonstationary time series, the analogous measures are detrended cross-correlations analysis (DCCA) and the recently proposed detrended cross-correlation coefficient, ?DCCA(T,n), where T is the total length of the time series and n the window size. For ?DCCA(T,n), we numerically calculated the Cauchy inequality -1??DCCA(T,n)?1. Here we derive -1??DCCA(T,n)?1 for a standard variance-covariance approach and for a detrending approach. For overlapping windows, we find the range of ?DCCA within which the cross-correlations become statistically significant. For overlapping windows we numerically determine—and for nonoverlapping windows we derive—that the standard deviation of ?DCCA(T,n) tends with increasing T to 1/T. Using ?DCCA(T,n) we show that the Chinese financial market's tendency to follow the U.S. market is extremely weak. We also propose an additional statistical test that can be used to quantify the existence of cross-correlations between two power-law correlated time series.

Podobnik, Boris; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Stanley, H. Eugene

2011-12-01

432

A ground system for early forest fire detection based on infrared signal processing  

Microsoft Academic Search

This article presents a ground remote automatic system for forest surveillance based on infrared signal processing applied to early fire detection. Advanced techniques, which are based on infrared signal processing, are used in order to process the captured images. With the aim of determining the presence or absence of fire, the system performs the fusion of different detectors that exploit

I. Bosch; S. Gómez; L. Vergara

2011-01-01

433

Intelligent Signal Processing Group, IMM, DTU / Jan Larsen 1 Search for sounds a machine learning approach  

E-print Network

Intelligent Signal Processing Group, IMM, DTU / Jan Larsen 1 Search for sounds ­ a machine learning Processing Group, IMM, DTU / Jan Larsen 2 Search for sounds ­ a machine learning approach The digital music will play a key role in future systems #12;Intelligent Signal Processing Group, IMM, DTU / Jan Larsen 3

434

Neural network post-processing of grayscale optical correlator  

NASA Technical Reports Server (NTRS)

In this paper we present the use of a radial basis function neural network (RBFNN) as a post-processor to assist the optical correlator to identify the objects and to reject false alarms. Image plane features near the correlation peaks are extracted and fed to the neural network for analysis. The approach is capable of handling large number of object variations and filter sets. Preliminary experimental results are presented and the performance is analyzed.

Lu, Thomas T; Hughlett, Casey L.; Zhoua, Hanying; Chao, Tien-Hsin; Hanan, Jay C.

2005-01-01

435

Does Neural Input or Processing Play a Greater Role in the Magnitude of Neuroimaging Signals?  

PubMed Central

An important constraint on how hemodynamic neuroimaging signals such as fMRI can be interpreted in terms of the underlying evoked activity is an understanding of neurovascular coupling mechanisms that actually generate hemodynamic responses. The predominant view at present is that the hemodynamic response is most correlated with synaptic input and subsequent neural processing rather than spiking output. It is still not clear whether input or processing is more important in the generation of hemodynamics responses. In order to investigate this we measured the hemodynamic and neural responses to electrical whisker pad stimuli in rat whisker barrel somatosensory cortex both before and after the local cortical injections of the GABAA agonist muscimol. Muscimol would not be expected to affect the thalamocortical input into the cortex but would inhibit subsequent intra-cortical processing. Pre-muscimol infusion whisker stimuli elicited the expected neural and accompanying hemodynamic responses to that reported previously. Following infusion of muscimol, although the temporal profile of neural responses to each pulse of the stimulus train was similar, the average response was reduced in magnitude by ?79% compared to that elicited pre-infusion. The whisker-evoked hemodynamic responses were reduced by a commensurate magnitude suggesting that, although the neurovascular coupling relationships were similar for synaptic input as well as for cortical processing, the magnitude of the overall response is dominated by processing rather than from that produced from the thalamocortical input alone. PMID:20740075

Harris, Sam; Jones, Myles; Zheng, Ying; Berwick, Jason

2010-01-01

436

Terahertz radiation from bacteriorhodopsin reveals correlated primary electron and proton transfer processes  

PubMed Central

The kinetics of electrogenic events associated with the different steps of the light-induced proton pump of bacteriorhodopsin is well studied in a wide range of time scales by direct electric methods. However, the investigation of the fundamental primary charge translocation phenomena taking place in the functional energy conversion process of this protein, and in other biomolecular assemblies using light energy, has remained experimentally unfeasible because of the lack of proper detection technique operating in the 0.1- to 20-THz region. Here, we show that extending the concept of the familiar Hertzian dipole emission into the extreme spatial and temporal range of intramolecular polarization processes provides an alternative way to study ultrafast electrogenic events on naturally ordered biological systems. Applying a relatively simple experimental arrangement based on this idea, we were able to observe light-induced coherent terahertz radiation from bacteriorhodopsin with femtosecond time resolution. The detected terahertz signal was analyzed by numerical simulation in the framework of different models for the elementary polarization processes. It was found that the principal component of the terahertz emission can be well described by excited-state intramolecular electron transfer within the retinal chromophore. An additional slower process is attributed to the earliest phase of the proton pump, probably occurring by the redistribution of a H bond near the retinal. The correlated electron and proton translocation supports the concept, assigning a functional role to the light-induced sudden polarization in retinal proteins. PMID:18456840

Groma, G. I.; Hebling, J.; Kozma, I. Z.; Váró, G.; Hauer, J.; Kuhl, J.; Riedle, E.

2008-01-01

437

600 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 45, NO. 3, MARCH 1997 Sparse Signal Reconstruction from  

E-print Network

, or the ill-posed nature of the problem and, often, from a combination of these factors. To treat this problem. A detailed discussion of this definition is given later in the paper. Thus, reconstruction of a sparse signal of a norm. This is different, for example, from basis selection in signal Manuscript received February 21

438

Processing of the Liquid Xenon calorimeter's signals for timing measurements  

NASA Astrophysics Data System (ADS)

One of the goals of the Cryogenic Magnetic Detector at Budker Institute of Nuclear Physics SB RAS (Novosibirsk, Russia) is a study of nucleons production in electron-positron collisions near threshold. The neutron-antineutron pair production events can be detected only by the calorimeters. In the barrel calorimeter the antineutron annihilation typically occurs by 5 ns or later after beams crossing. For identification of such events it is necessary to measure the time of flight of particles to the LXe-calorimeter with accuracy of about 3 ns. The LXe-calorimeter consists of 14 layers of ionization chambers with anode and cathode readout. The duration of charge collection to the anodes is about 4.5 mks, while the required accuracy of measuring of the signal arrival time is less than 1/1000 of that. Besides, the signals' shapes differ substantially from event to event, so the signal arrival time is measured in two stages. At the first stage, the signal arrival time is determined with an accuracy of 1–2 discretization periods, and initial values of parameters for subsequent fitting procedure are calculated. At the second stage, the signal arrival time is determined with the required accuracy by means of fitting of the signal waveform with a template waveform. To implement that, a special electronics has been developed which performs waveform digitization and On-Line measurement of signals' arrival times and amplitudes.

Epshteyn, L. B.; Yudin, Yu V.

2014-09-01

439

Deriving respiration from pulse wave: a new signal-processing technique.  

PubMed

Investigations of autonomic nervous system activity using spectral analysis of heart rate (HR) and blood pressure (BP) variability is very popular in many scientific disciplines, and yet only half of all studies involving spectral analysis control for respiration. Because respiration modulates HR and BP variability, knowledge of the respiratory rate is necessary for the proper interpretation of HR and BP power spectra. We devised and validated a new signal-processing technique to derive respiration from the blood pressure wave. This technique is based on the relationship between oscillations in the area under the dicrotic notch of the pulse wave and respiration. The results of our view signal-processing technique yielded significant correlations between protocols of the actual number of respiratory cycles and our blood pressure-derived respiratory cycles and their respective spectra for a number of standard autonomic tests (P < 0.05). Our method will allow retrospective extraction of the respiratory wave and as such afford a more precise interpretation of HR and BP spectra. PMID:8928873

De Meersman, R E; Zion, A S; Teitelbaum, S; Weir, J P; Lieberman, J; Downey, J

1996-05-01

440

Statistical Signal Processing Methods in Scattering and Imaging  

NASA Astrophysics Data System (ADS)

This Ph.D. dissertation project addresses two related topics in wave-based signal processing: 1) Cramer-Rao bound (CRB) analysis of scattering systems formed by pointlike scatterers in one-dimensional (1D) and three-dimensional (3D) spaces. 2) Compressive optical coherent imaging, based on the incorporation of sparsity priors in the reconstructions. The first topic addresses for wave scattering systems in 1D and 3D spaces the information content about scattering parameters, in particular, the targets' positions and strengths, and derived quantities, that is contained in scattering data corresponding to reflective, transmissive, and more general sensing modalities. This part of the dissertation derives the Cramer-Rao bound (CRB) for the estimation of parameters of scalar wave scattering systems formed by point scatterers. The results shed light on the fundamental difference between the approximate Born approximation model for weak scatterers and the more general multiple scattering model, and facilitate the identification of regions in parameter space where multiple scattering facilitates or obstructs the estimation of parameters from scattering data, as well as of sensing configurations giving maximal or minimal information about the parameters. The derived results are illustrated with numerical examples, with particular emphasis on the imaging resolution which we quantify via a relative resolution index borrowed from a previous paper. Additionally, this work investigates fundamental limits of estimation performance for the localization of the targets and the inverse scattering problem. The second topic of the effort describes a novel compressive-sensing-based technique for optical imaging with a coherent single-detector system. This hybrid opto-micro-electromechanical, coherent single-detector imaging system applies the latest developments in the nascent field of compressive sensing to the problem of computational imaging of wavefield intensity from a small number of projective measurements of the field. The projective measurements are implemented using spatial light modulators of the digital micromirror device (DMD) family, followed by a geometrical-optics-based image casting system to capture the data using a single photodetector. The reconstruction process is based on the new field of compressive sensing which allows, thanks to the exploitation of statistical priors such as sparsity, the imaging of the main features of the objects under illumination with much less data than a typical CCD camera. The present system expands the scope of single-detector imaging systems based on compressive sensing from the incoherent light regime, which has been the past focus, to the coherent light regime which is key in many biomedical and Homeland security applications (THz imaging).

Zambrano Nunez, Maytee

441

Postdoctoral Scholar position Area: Electronics and Signal Processing for Nanocomposite based Sensors  

E-print Network

Postdoctoral Scholar position Area: Electronics and Signal Processing for Nanocomposite based with nanocomposites based sensor applications. Job Description: A position is available in the Micro Engineering

de Leon, Alex R.

442

Carlos Busso and Tauhidur Rahman Multimodal Signal Processing (MSP) Laboratory  

E-print Network

anger[Busso et al., 2009] §Major limitation in many behavioral areas: §Depression §Post-traumatic stress disorder (PTSD) §Analysis per acoustic feature group in the valence dimension §Energy, F0, voice quality [Correlation] Without CFS [Correlation] Valence 0.2161 0.3245 Activation 0.5497 0.8035 Dominance 0

Busso, Carlos

443

Suppressing correlated noise in signals transmitted over the Gaussian memory channels using a 2 N -port splitter and phase flips  

NASA Astrophysics Data System (ADS)

A scheme for suppressing the correlated noise in signals transmitted over the bosonic Gaussian memory channels is proposed. This is a compromise solution rather than removing the noise completely. The scheme is based on linear optical elements, two N -port splitters and N number of phase flips. The proposed scheme has the advantages that the correlated noise of the memory channels is greatly suppressed, and the input signal states can be protected excellently when transmitting over the noise channels. We examine the suppressing efficiency of the scheme for the correlated noise, both from quantum information of the states directly transmitted through the noise channel and also from the entanglement teleportation. The operation of phase flips in our scheme is important for the suppression of the correlated noise, which can diminish the effect of noise in quantum communication. Increasing the number of beam splitters also can improve the suppressing efficiency of the scheme in quantum communication.

Jiang, Ke-Xia; Zhang, Shi-Quan; Ke, San-Min; Fan, Heng

2014-11-01

444

High-resolution correlation  

NASA Astrophysics Data System (ADS)

In the basic correlation process a sequence of time-lag-indexed correlation coefficients are computed as the inner or dot product of segments of two signals. The time-lag(s) for which the magnitude of the correlation coefficient sequence is maximized is the estimated relative time delay of the two signals. For discrete sampled signals, the delay estimated in this manner is quantized with the same relative accuracy as the clock used in sampling the signals. In addition, the correlation coefficients are real if the input signals are real. There have been many methods proposed to estimate signal delay to more accuracy than the sample interval of the digitizer clock, with some success. These methods include interpolation of the correlation coefficients, estimation of the signal delay from the group delay function, and beam forming techniques, such as the MUSIC algorithm. For spectral estimation, techniques based on phase differentiation have been popular, but these techniques have apparently not been applied to the correlation problem . We propose a phase based delay estimation method (PBDEM) based on the phase of the correlation function that provides a significant improvement of the accuracy of time delay estimation. In the process, the standard correlation function is first calculated. A time lag error function is then calculated from the correlation phase and is used to interpolate the correlation function. The signal delay is shown to be accurately estimated as the zero crossing of the correlation phase near the index of the peak correlation magnitude. This process is nearly as fast as the conventional correlation function on which it is based. For real valued signals, a simple modification is provided, which results in the same correlation accuracy as is obtained for complex valued signals.

Nelson, D. J.

2007-09-01

445

Processing multispectral signals from a discrete-sensor array  

NASA Technical Reports Server (NTRS)

Technique encoding and decoding color-image signals from array of discrete sensors can simplify fabrication of remote-sensing imaging system. Imaging system projects output on charge-coupled-device array. Computerized matrix decoding scheme decodes image.

Wellman, J. B.

1979-01-01

446

Signal Processing for Passive Radar Using OFDM Waveforms  

Microsoft Academic Search

Passive radar is a concept where illuminators of opportunity are used in a multistatic radar setup. New digital signals, like digital audio\\/video broadcast (DAB\\/DVB), are excellent candidates for this scheme, as they are widely available, can be easily decoded to acquire the noise-free signal, and employ orthogonal frequency division multiplex (OFDM). Multicarrier transmission schemes like OFDM use block channel equalization

Christian R. Berger; Bruno Demissie; Jörg Heckenbach; Peter Willett; Shengli Zhou

2010-01-01

447

Measuring Postural Stability: Strategies For Signal Acquisition And Processing  

NASA Astrophysics Data System (ADS)

A balance platform was used to collect postural stability data from 60 children, approximately half of whom have been diagnosed with cerebral palsy. The data was examined with respect to its frequency content, resulting in an improved strategy for frequency estimation. With a reliable assessment of the frequency domain characteristics, the signal stationarity could then be examined. Significant differences in signal stationarity were observed when the epoch length was changed, as well as between the normal and cerebral palsy populations.

Riedel, Susan A.; Harris, Gerald F.

1987-01-01

448

Activated polarization pulling and de-correlation of signal and pump states of polarization in a fiber Raman amplifier.  

PubMed

We report on a theoretical study of activated polarization pulling and de-correlation of signal and pump states of polarization based on an advanced vector model of a fiber Raman amplifier accounting for random birefringence and two-scale fiber spinning. As a result, we have found that it is possible to provide de-correlation and simultaneously suppress PDG and PMD to 1.2 dB and 0.035 ps/km(1/2) respectively. PMID:22109453

Sergeyev, Sergey V

2011-11-21

449

Analog CMOS Design for Optical Coherence Tomography Signal Detection and Processing  

Microsoft Academic Search

A CMOS circuit was designed and fabricated for optical coherence tomography (OCT) signal detection and processing. The circuit includes a photoreceiver, differential gain stage and lock-in amplifier based demodulator. The photoreceiver consists of a CMOS photodetector and low noise differential transimpedance amplifier which converts the optical interference signal into a voltage. The differential gain stage further amplifies the signal. The

Wei Xu; David L. Mathine; Jennifer K. Barton

2008-01-01

450

Lab 1: Kirchoff's Law & OpAmp Circuits CEE370 Sensors, Electrical Circuits, and Signal Processing  

E-print Network

Lab 1: Kirchoff's Law & OpAmp Circuits CEE370 ­ Sensors, Electrical Circuits, and Signal;Lab 1: Kirchoff's Law & OpAmp Circuits CEE370 ­ Sensors, Electrical Circuits, and Signal ­ Sensors, Electrical Circuits, and Signal Processing Kirchhoff's Voltage Law (KVL): The algebraic sum

Lynch, Jerome P.

451

Signal processing for order 10 pm accuracy displacement metrology in real-world scientific applications  

NASA Technical Reports Server (NTRS)

This paper describes heterodyne displacement metrology gauge signal processing methods that achieve satisfactory robustness against low signal strength and spurious signals, and good long-term stability. We have a proven displacement-measuring approach that is useful not only to space-optical projects at JPL, but also to the wider field of distance measurements.

Halverson, Peter G.; Loya, Frank M.

2004-01-01

452

A Reversible Process Calculus and the Modelling of the ERK Signalling Pathway  

E-print Network

A Reversible Process Calculus and the Modelling of the ERK Signalling Pathway Iain Phillips Irek and key identi- fiers to control execution. As an application of our calculus, we model the ERK signalling in the ERK signalling pathway described in Section 3 is a good example. Simplifying, let us assume

Ulidowski, Irek

453

Correlation  

Microsoft Academic Search

Reviews 7 studies in the area of interpretation of correlation from the psychological point of view. The limitations and meanings of correlation methods have also been given. The statistical methods of calculating correlation, as given by 8 psychologists have been reported. Presents 22 reports, given by various psychologists, who have evaluated the tests using various correlation methods. Six studies were

James Burt Miner

1919-01-01