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1

Multichannel heterodyning for wideband interferometry, correlation and signal processing  

DOEpatents

A method of signal processing a high bandwidth signal by coherently subdividing it into many narrow bandwidth channels which are individually processed at lower frequencies in a parallel manner. Autocorrelation and correlations can be performed using reference frequencies which may drift slowly with time, reducing cost of device. Coordinated adjustment of channel phases alters temporal and spectral behavior of net signal process more precisely than a channel used individually. This is a method of implementing precision long coherent delays, interferometers, and filters for high bandwidth optical or microwave signals using low bandwidth electronics. High bandwidth signals can be recorded, mathematically manipulated, and synthesized.

Erskine, David J. (Oakland, CA)

1999-01-01

2

Task effects on BOLD signal correlates of implicit syntactic processing  

PubMed Central

BOLD signal was measured in sixteen participants who made timed font change detection judgments in visually presented sentences that varied in syntactic structure and the order of animate and inanimate nouns. Behavioral data indicated that sentences were processed to the level of syntactic structure. BOLD signal increased in visual association areas bilaterally and left supramarginal gyrus in the contrast of sentences with object- and subject-extracted relative clauses without font changes in which the animacy order of the nouns biased against the syntactically determined meaning of the sentence. This result differs from the findings in a non-word detection task (Caplan et al, 2008a), in which the same contrast led to increased BOLD signal in the left inferior frontal gyrus. The difference in areas of activation indicates that the sentences were processed differently in the two tasks. These differences were further explored in an eye tracking study using the materials in the two tasks. Issues pertaining to how parsing and interpretive operations are affected by a task that is being performed, and how this might affect BOLD signal correlates of syntactic contrasts, are discussed. PMID:20671983

Caplan, David

2010-01-01

3

Model-Based Signal Processing: Correlation Detection With Synthetic Seismograms  

NASA Astrophysics Data System (ADS)

Recent applications of correlation methods to seismological problems illustrate the power of coherent signal processing applied to seismic waveforms. Examples of these applications include detection of low amplitude signals buried in ambient noise and cross-correlation of sets of waveforms to form event clusters and accurately measure delay times for event relocation and/or earth structure. These methods rely on the exploitation of the similarity of individual waveforms and have been successfully applied to large sets of empirical observations. However, in cases with little or no empirical event data, such as aseismic regions or exotic event types, correlation methods with observed seismograms will not be possible due to the lack of previously observed similar waveforms. This study uses model-based signals computed for three-dimensional (3D) Earth models to form the basis for correlation detection. Synthetic seismograms are computed for fully 3D models estimated from the Markov Chain Monte-Carlo (MCMC) method. MCMC uses stochastic sampling to fit multiple seismological data sets. Rather than estimate a single "optimal" model, MCMC results in a suite of models that sample the model space and incorporates uncertainty through variability of the models. The variability reflects our ignorance of Earth structure, due to limited resolution, data and modeling errors, and produces variability in the seismic waveform response. Model-based signals are combined using a subspace method where the synthetic signals are decomposed into an orthogonal basis by singular-value decomposition (SVD) and the observed waveforms are represented with a linear combination of a sub-set of eigenvectors (signals) associated with the most significant eigenvalues. We have demonstrated the method by modeling long-period (80-10 seconds) regional seismograms for a moderate (M~5) earthquake near the China-North Korea border. Synthetic seismograms are computed with the Spectral Element Method for a suite of long-wavelength (2 degree) seismic velocity models based on the MCMC method. We are working on higher resolution (1 degree) models for the same region and methods to increase the frequency content of the synthetic seismograms using both 1D reflectivity synthetics and 3D synthetics with a recently developed elastic finite difference code.

Rodgers, A.; Harris, D.; Pasyanos, M.; Blair, S.; Matt, R.

2006-12-01

4

Queueing up for enzymatic processing: correlated signaling through coupled degradation  

PubMed Central

High-throughput technologies have led to the generation of complex wiring diagrams as a post-sequencing paradigm for depicting the interactions between vast and diverse cellular species. While these diagrams are useful for analyzing biological systems on a large scale, a detailed understanding of the molecular mechanisms that underlie the observed network connections is critical for the further development of systems and synthetic biology. Here, we use queueing theory to investigate how ‘waiting lines' can lead to correlations between protein ‘customers' that are coupled solely through a downstream set of enzymatic ‘servers'. Using the E. coli ClpXP degradation machine as a model processing system, we observe significant cross-talk between two networks that are indirectly coupled through a common set of processors. We further illustrate the implications of enzymatic queueing using a synthetic biology application, in which two independent synthetic networks demonstrate synchronized behavior when common ClpXP machinery is overburdened. Our results demonstrate that such post-translational processes can lead to dynamic connections in cellular networks and may provide a mechanistic understanding of existing but currently inexplicable links. PMID:22186735

Cookson, Natalie A; Mather, William H; Danino, Tal; Mondragon-Palomino, Octavio; Williams, Ruth J; Tsimring, Lev S; Hasty, Jeff

2011-01-01

5

Study of photon correlation techniques for processing of laser velocimeter signals  

NASA Technical Reports Server (NTRS)

The objective was to provide the theory and a system design for a new type of photon counting processor for low level dual scatter laser velocimeter (LV) signals which would be capable of both the first order measurements of mean flow and turbulence intensity and also the second order time statistics: cross correlation auto correlation, and related spectra. A general Poisson process model for low level LV signals and noise which is valid from the photon-resolved regime all the way to the limiting case of nonstationary Gaussian noise was used. Computer simulation algorithms and higher order statistical moment analysis of Poisson processes were derived and applied to the analysis of photon correlation techniques. A system design using a unique dual correlate and subtract frequency discriminator technique is postulated and analyzed. Expectation analysis indicates that the objective measurements are feasible.

Mayo, W. T., Jr.

1977-01-01

6

A Correlation-Based Watermarking Technique of 3-D Meshes via Cyclic Signal Processing  

NASA Astrophysics Data System (ADS)

This paper describes a blind watermarking scheme through cyclic signal processing. Due to various rapid networks, there is a growing demand of copyright protection for multimedia data. As efficient watermarking of images, there exist two major approaches: a quantization-based method and a correlation-based method. In this paper, we proposes a correlation-based watermarking technique of three-dimensional (3-D) polygonal models using the fast Fourier transforms (FFTs). For generating a watermark with desirable properties, similar to a pseudonoise signal, an impulse signal on a two-dimensional (2-D) space is spread through the FFT, the multiplication of a complex sinusoid signal, and the inverse FFT. This watermark, i.e., spread impulse signal, in a transform domain is converted to a spatial domain by an inverse wavelet transform, and embedded into 3-D data aligned by the principle component analysis (PCA). In the detection procedure, after realigning the watermarked mesh model through the PCA, we map the 3-D data on the 2-D space via block segmentation and averaging operation. The 2-D data are processed by the inverse system, i.e., the FFT, the division of the complex sinusoid signal, and the inverse FFT. From the resulting 2-D signal, we detect the position of the maximum value as a signature. For 3-D bunny models, detection rates and information capacity are shown to evaluate the performance of the proposed method.

Uto, Toshiyuki; Takemura, Yuka; Kamitani, Hidekazu; Ohue, Kenji

7

Digital Signal Processing using Stream High Performance Computing: A 512-input Broadband Correlator for Radio Astronomy  

E-print Network

A "large-N" correlator that makes use of Field Programmable Gate Arrays and Graphics Processing Units has been deployed as the digital signal processing system for the Long Wavelength Array station at Owens Valley Radio Observatory (LWA-OV), to enable the Large Aperture Experiment to Detect the Dark Ages (LEDA). The system samples a ~100MHz baseband and processes signals from 512 antennas (256 dual polarization) over a ~58MHz instantaneous sub-band, achieving 16.8Tops/s and 0.236 Tbit/s throughput in a 9kW envelope and single rack footprint. The output data rate is 260MB/s for 9 second time averaging of cross-power and 1 second averaging of total-power data. At deployment, the LWA-OV correlator was the largest in production in terms of N and is the third largest in terms of complex multiply accumulations, after the Very Large Array and Atacama Large Millimeter Array. The correlator's comparatively fast development time and low cost establish a practical foundation for the scalability of a modular, heterogeneo...

Kocz, J; Barsdell, B R; Price, D; Bernardi, G; Bourke, S; Clark, M A; Craig, J; Dexter, M; Dowell, J; Eftekhari, T; Ellingson, S; Hallinan, G; Hartman, J; Jameson, A; MacMahon, D; Taylor, G; Schinzel, F; Werthimer, D

2014-01-01

8

Digital Signal Processing Tools  

NSDL National Science Digital Library

A collection of seven Java applets and associated tutorials are available on this site from the Signals and Systems Group at the University of Edinburgh. The tools illustrate various concepts of digital signal processing, like convolution, correlation, the Fourier transform, and discrete-time applications of each. Seven other applets that demonstrate more advanced concepts are also available, but no documentation or explanation accompanies them. A few conference publications and reports related to these educational materials are presented.

2000-01-01

9

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.

2012-12-26

10

Dual waveband signal processing system  

NASA Astrophysics Data System (ADS)

A Dual Waveband Signal Processing System (DWSPS) is disclosed for differentiating between an primary target signal and background clutter to detect targets and objects with a particularly unique spectral characteristic. The DWSPS is responsive to a plurality of sensors operating on different wavelengths. The output wavebands of the sensors are filtered by either spatial or temporal high-pass filters, and is processed through a network comprising a series of multipliers, dividers, comparators, and subtractors to obtain the weighted correlation functions or Alpha Coefficients, which, when compared to the input wavebands, produces a filtered or processed output signal of the detected features.

Pauli, Myron; Inderhess, John; Katz, Garry; Faraedrich, Doug; Nordmeyer, Dan

1992-06-01

11

Geophysical signal processing  

SciTech Connect

Draws together a number of areas of knowledge to give unified coverage of the subject: the geophysical applications of digital signal processing. The presentation has a strong applications orientation. The coverage connects and unifies several fields, namely wave propagation, digital signal processing, spectral analysis, and computer methods. The book covers many topics in depth.

Robinson, E.A.; Durrani, T.S.

1986-01-01

12

Microwave photonic signal processing.  

PubMed

Photonic signal processing offers the advantages of large time-bandwidth capabilities to overcome inherent electronic limitations. In-fibre signal processors are inherently compatible with fibre optic microwave systems that can integrate with wireless antennas, and can provide connectivity with in-built signal conditioning and electromagnetic interference immunity. Recent methods in wideband and adaptive signal processing, which address the challenge of realising programmable microwave photonic phase shifters and true-time delay elements for phased array beamforming; ultra-wideband Hilbert transformers; single passband, widely tunable, and switchable microwave photonic filters; and ultra-wideband microwave photonic mixers, are described. In addition, a new microwave photonic mixer structure is presented, which is based on using the inherent frequency selectivity of the stimulated Brillouin scattering loss spectrum to suppress the carrier of a dual-phase modulated optical signal. Results for the new microwave photonic mixer demonstrate an extremely wide bandwidth operation of 0.2 to 20 GHz and a large conversion efficiency improvement compared to the conventional microwave photonic mixer. PMID:24104178

Minasian, R A; Chan, E H W; Yi, X

2013-09-23

13

Signal processing with higher-order spectra  

Microsoft Academic Search

The strengths and limitations of correlation-based signal processing methods are discussed. The definitions, properties, and computation of higher-order statistics and spectra, with emphasis on the bispectrum and trispectrum are presented. Parametric and nonparametric expressions for polyspectra of linear and nonlinear processes are described. The applications of higher-order spectra in signal processing are discussed

C. L. Nikias; J. M. Mendel

1993-01-01

14

Radar signal processing  

NASA Astrophysics Data System (ADS)

The role of clutter in radar signal processing is considered with particular reference to an air-traffic environment. The characteristics of clutter are described, and the use of conventional moving-target indication filters to reduce the effects of clutter is considered. Adaptive clutter suppression schemes are addressed, and the adaptive detection of a moving target in the presence of clutter of unknown statistics is discussed. The use of a parametric spectrum estimation procedure as the basis of clutter classification is described.

Haykin, S.

1985-04-01

15

Digital signal processing  

NASA Astrophysics Data System (ADS)

Computationally efficient digital signal-processing algorithms over finite fields are developed analytically, and the relationship of these algorithms to algebraic error-correcting codes is explored. A multidisciplinary approach is employed, in an effort to make the results accessible to engineers, mathematicians, and computer scientists. Chapters are devoted to systems of bilinear forms, efficient finite-field algorithms, multidimensional methods, a new class of linear codes, and a new error-control scheme.

Morgera, Salvatore D.; Krishna, Hari

16

Introduction to Communication, Control, and Signal Processing  

NSDL National Science Digital Library

This course explores ideas involving signals, systems and probabilistic models in the context of communication, control and signal processing applications. The material expands out from the basics in 6.003 and 6.041. The treatment involves aspects of analysis, synthesis, and optimization. Topics covered include:-random processes-correlations-spectral densities-state-space modeling-multirate processing-signal estimation-detection

Oppenheim, Alan; Verghese, George

2008-11-05

17

signal processing and oral communication  

E-print Network

communication Introduction 4 Dysarthria #12;SPOClab signal processing and oral communication Automatic speech processing and oral communication Dysarthria Neuro-motor articulatory difficulties resulting Dysarthria and ASR word accuracy Non-dysarthric Dysarthric Background 7 #12;SPOClab signal processing

Penn, Gerald

18

Correlation properties of the vector signal representation for speckle pattern.  

PubMed

In one-dimensional (1D) signal analysis, the complex analytic signal built from a real-valued signal and its Hilbert transform is an important tool providing a mathematical foundation for 1D statistical analysis. For a natural extension beyond 1D signal, Riesz transform has been applied to high-dimensional signal processing as a generalized Hilbert transform to construct a vector signal representation and therefore, to enlarge the traditional analytic signal concept. In this paper, we introduce the vector correlations as new mathematical tools for vector calculus for statistical speckle analysis. Based on vector correlations of a real-valued speckle pattern, we present the associated correlation properties, which can be regarded as mathematical foundation for the vector analysis in speckle metrology. PMID:24787197

Wang, Wei; Zhang, Shun; Ma, Ning

2014-04-01

19

Data-adaptive principal component signal processing  

Microsoft Academic Search

Principal component (eigenvalue-eigenvector) analysis is applied to processing of narrow band signals in noise. The amount of data available is assumed to be limited. Principal eigenvalues and eigenvectors of a sample correlation matrix are used to improve the signal to noise ratio (SNR) in the data and to increase the resolution capability of nonlinear least squares at low SNR and

Ramdas Kumaresan; D. W. Tufts

1980-01-01

20

Correlation Statistics of Quantized Noiselike Signals  

E-print Network

I calculate the statistics of correlation of two digitized noiselike signals, which are drawn from complex Gaussian distributions, sampled, quantized, correlated, and averaged. Averaged over many such samples, the correlation r approaches a Gaussian distribution. The mean and variance of r fully characterize the distribution of r. The mean corresponds to the reproducible part of the measurement, and the variance corresponds to the random part, or noise. I investigate the case of nonnegligible covariance rho between the signals. Noise in the correlation can increase or decrease, depending on quantizer parameters, when rho increases. This contrasts with the correlation of continuously valued or unquantized signals, for which the noise in phase with rho increases with increasing rho, and noise out of phase decreases. Indeed, for some quantizer parameters, I find that the correlation of quantized signals provides a more accurate estimate of rho than would correlation without quantization. I present analytic results in exact form and as polynomial expansions, and compare these mathematical results with results of computer simulations.

Carl Gwinn

2006-03-04

21

A signal processing cell architecture  

Microsoft Academic Search

A data flow general purpose digital signal processor has been previously developed [1] for real time applications of digital signal processing. The Data Flow Signal Processor (DFSP) is attached to a host computer, and is based on a binary tree structure. It employs two types of cells: processing and arithmetic cells, and utilizes residue number system [2] for arithmetic operations.

M. M. JAMALI; M. M. HUSSAIN; G. A. JULLIEN

1987-01-01

22

Nanotubes for noisy signal processing  

NASA Astrophysics Data System (ADS)

Nanotubes can process noisy signals. We present two central results in support of this general thesis and make an informed extrapolation that uses nanotubes to improve body armor. The first result is that noise can help nanotubes detect weak signals. The finding confirmed a stochastic-resonance theoretical prediction that noise can enhance detection at the nano-level. Laboratory experiments with nanotubes showed that three types of noise improved three measures of detection. Small amounts of Gaussian, uniform, and Cauchy additive white noise increased mutual-information, cross-correlation, and bit-error-rate measures before degrading them with further increases in noise. Nanotubes can apply this noise-enhancement and nanotube electrical and mechanical properties to improve signal processing. Similar noise enhancement may benefit a proposed nanotube-array cochlear-model spectral processing. The second result is that nanotube antennas can directly detect narrowband electromagnetic (EM) signals. The finding showed that nanotube and thin-wire dipoles are similar: They are resonant and narrowband and can implement linear-array designs if the EM waves in the nanotubes propagate at or near the free-space velocity of light. The nanotube-antenna prediction is based on a Fresnel-zone or near-zone analysis of antenna impedance using a quantum-conductor model. The analysis also predicts a failure to resonate if the nanotube EM-wave propagation is much slower than free-space light propagation. We extrapolate based on applied and theoretical analysis of body armor. Field experiments used a baseball comparison and statistical and other techniques to model body-armor bruising effects. A baseball comparison showed that a large caliber handgun bullet can hit an armored chest as hard as a fast baseball can hit a bare chest. Adaptive fuzzy systems learned to predict a bruise profile directly from the experimental data and also from statistical analysis of the data. Nanotube signal processing should help disguise armor by adapting camouflage to match changing backgrounds while nanotube additives should strengthen armor materials.

Lee, Ian Yenyin

23

Forensic applications of signal processing  

Microsoft Academic Search

This article highlights some problems encountered by forensic signal processing experts in the area of speech and video processing. We have demonstrated that there is a need for speech, video, and other signal processing experts within the IEEE community to work together to provide standardized guidelines to court systems around the world to assist them in dealing with this complex

J. Tibbitts; Yibin Lu

2009-01-01

24

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

25

Digital Signal Processing applied to Physical Signals  

E-print Network

It is well known that many of the scientific and technological discoveries of the XXI century will depend on the capability of processing and understanding a huge quantity of data. With the advent of the digital era, a fully digital and automated treatment can be designed and performed. From data mining to data compression, from signal elaboration to noise reduction, a processing is essential to manage and enhance features of interest after every data acquisition (DAQ) session. In the near future, science will go towards interdisciplinary research. In this work there will be given an example of the application of signal processing to different fields of Physics from nuclear particle detectors to biomedical examinations. In Chapter 1 a brief description of the collaborations that allowed this thesis is given, together with a list of the publications co-produced by the author in these three years. The most important notations, definitions and acronyms used in the work are also provided. In Chapter 2, the last r...

Alberto, Diego; Musa, L

2011-01-01

26

Wave-based signal processing  

Microsoft Academic Search

The efficacy of imbedding knowledge of wave-scattering phenomenology into the processing of remote-sensing data is examined. In particular, the processing of radar and sonar phase history and synthetic-aperture imagery is considered. Algorithms are developed for effecting signal denoising, feature extraction (for use in target identification\\/classification) and detection. Three classes of algorithms are presented: (1) superresolution, (2) adaptive-signal decomposition, and (3)

Mark Richard McClure

1998-01-01

27

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.

28

Signal Processing in Cognitive Radio  

Microsoft Academic Search

Cognitive radio allows for usage of licensed frequency bands by unlicensed users. However, these unlicensed (cognitive) users need to monitor the spectrum continuously to avoid possible interference with the licensed (primary) users. Apart from this, cognitive radio is expected to learn from its surroundings and perform functions that best serve its users. Such an adaptive technology naturally presents unique signal-processing

Jun Ma; Geoffrey Ye Li; Biing Hwang Juang

2009-01-01

29

Flash ADC data processing with correlation coefficients  

E-print Network

The large growth of flash ADC techniques for processing signals, especially in applications of streaming data, raises issues such as data flow through an acquisition system, long-term storage, and greater complexity in data analysis. In addition, experiments that push the limits of sensitivity need to distinguish legitimate signals from noise. The use of correlation coefficients is examined to address these issues. They are found to be quite successful well into the noise region. The methods can also be extended to Field Programmable Gate Array modules for compressing the data flow and greatly enhancing the event rate capabilities.

D. Blyth; M. Gibson; D. Mcfarland; J. R. Comfort

2013-12-05

30

Wave-based signal processing  

NASA Astrophysics Data System (ADS)

The efficacy of imbedding knowledge of wave-scattering phenomenology into the processing of remote-sensing data is examined. In particular, the processing of radar and sonar phase history and synthetic-aperture imagery is considered. Algorithms are developed for effecting signal denoising, feature extraction (for use in target identification/classification) and detection. Three classes of algorithms are presented: (1) superresolution, (2) adaptive-signal decomposition, and (3) template matching. A superresolution signal-processing algorithm is used for the identification of wavefronts from the fields scattered from several canonical targets. Particular wave objects that are examined are single and multiple edge diffraction, scattering from flat and curved surfaces, cone diffraction, and creeping waves. General properties of superresolution processing of such data--independent of the particular algorithm used--are assessed through examination of the Cramer-Rao bounds. The method of matching pursuits is used to effect data-adaptive signal decomposition. This algorithm utilizes a nonlinear iterative procedure to project a given waveform onto a particular dictionary. For scattering problems, the most appropriate dictionary is composed of waveobjects consistent with the underlying wave phenomenology. A signal scattered from most targets of interest can be decomposed in terms of wavefronts, resonances, and chirps--and each of these subclasses can be further subdivided based on characteristic wave physics. Here the efficacy of applying the method of matching pursuits with a wave-based dictionary is examined, for the processing of scattering data. Detection test statistics are derived based on matching-pursuits results from each dictionary separately as well as with the cumulative results from multiple dictionaries. Examples are presented using measured data, for wideband, time-domain acoustic scattering from a submerged elastic shell. Finally, a full-wave electromagnetic-scattering model is utilized to effect a landmine detector via a multiresolution template-matching-like algorithm. Detection is performed on fully polarimetric ultra-wideband (50-1200 MHz) synthetic aperture radar (SAR) imagery. Multiresolution template matching is effected via discrete-wavelet transform (DWT) of the SAR imagery and the parametric target-signatures (templates). Detector results are presented and compared with those obtained using alternative techniques.

McClure, Mark Richard

31

Adaptive techniques for signal processing in communications  

NASA Astrophysics Data System (ADS)

The basic characteristics of adaptive signal processing techniques are described. Consideration is given to adaptive equalization; adaptive echo cancellation; adaptive noise cancellation; and linear predictive coding. The principle classes of signal processing systems are discussed, including: adaptive systems identification systems; signal estimation systems; and signal correction systems. The main components of adaptive processing routines are also described, with attention given to a priori knowledge; quality criteria; adaptive signal processing algorithms; and gradients methods. Block diagrams of the different adaptive processing systems are provided.

Claasen, T. A. C. M.; Mecklenbraeuker, W. F. G.

1985-11-01

32

Subsurface conductive isolation of refraction correlative magnetic signals (SCIRCMS)  

E-print Network

Isolation of terrestrially-observed magnetic signals by restoring their diffusive loss due to subsurface electrical conductivity sufficiently correlates these signals with those derived from the Alfven ionospheric electron movement of refraction...

Erck, Eric Stephenson

2004-11-15

33

Advanced detectors and signal processing  

NASA Technical Reports Server (NTRS)

Continued progress is reported toward development of a silicon on garnet technology which would allow fabrication of advanced detection and signal processing circuits on bubble memories. The first integrated detectors and propagation patterns have been designed and incorporated on a new mask set. In addition, annealing studies on spacer layers are performed. Based on those studies, a new double layer spacer is proposed which should reduce contamination of the silicon originating in the substrate. Finally, the magnetic sensitivity of uncontaminated detectors from the last lot of wafers is measured. The measured sensitivity is lower than anticipated but still higher than present magnetoresistive detectors.

Greve, D. W.; Rasky, P. H. L.; Kryder, M. H.

1986-01-01

34

ADAPTIVE OPTICAL SIGNAL PROCESSING FOR MICROWAVE-CARRIER BROADBAND SIGNALS  

E-print Network

ADAPTIVE OPTICAL SIGNAL PROCESSING FOR MICROWAVE-CARRIER BROADBAND SIGNALS Paul Smith, Zoya Popovic optical circuitry. The optical circuitry adaptively extracts the principal component of the received optical circuitry. The optical circuitry adaptively extracts the principal component of the received

Popovic, Zoya

35

A Note on Sampling of Signal and Partially Correlated Noise  

Microsoft Academic Search

Signal-to-noise improvement in sampled data systems is a function of the number of samples and the degree of correlation of signal and noise samples. This correspondence demonstrates the power of the autocorrelation function in establishing the effectiveness of digital filtering, and provides a method for determining signal-to-noise improvement factors.

Elihu Levine

1968-01-01

36

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

37

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

38

CTC assisted PR box type correlation can lead to signaling  

E-print Network

It is known that there exist non-local correlations that respect no-signaling criterion, but violate Bell-type inequalities more than quantum-mechanical correlations. Such super quantum correlations were introduced as the Popescu-Rohrlich (PR) box. We consider such non-local boxes with two/three inputs and two/three outputs. We show that these super quantum correlations can lead to signaling when at least one of the input bit has access to a word line along a closed time-like curve.

Indranil Chakrabarty; Tanumoy Pramanik; Arun K Pati; Pankaj Agrawal

2011-07-14

39

Optimization of Correlated Responses of EDM Process  

Microsoft Academic Search

Electrical discharge machining (EDM) process has several important performance measures (responses), some of which are correlated. For example, material removal rate (MRR) and electrode wear rate (EWR) are highly correlated. No reported research work on EDM process has taken into consideration the possible correlation between the response variables while determining the optimal process conditions. Thus, the results achieved by the

Rina Chakravorty; Susanta Kumar Gauri; Shankar Chakraborty

2011-01-01

40

Optimization of Correlated Responses of EDM Process  

Microsoft Academic Search

Electrical discharge machining (EDM) process has several important performance measures (responses), some of which are correlated. For example, material removal rate (MRR) and electrode wear rate (EWR) are highly correlated. No reported research work on EDM process has taken into consideration the possible correlation between the response variables while determining the optimal process conditions. Thus, the results achieved by the

Rina Chakravorty; Susanta Kumar Gauri; Shankar Chakraborty

2012-01-01

41

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 ...

Detmold, William

42

Correlating Notch Signaling with Thymocyte Maturation  

Microsoft Academic Search

The Notch receptor and its ligands are involved in many developmental processes. They are highly expressed in the thymus and have been implicated in the CD4 versus CD8 lineage decision. We identified the constitutively active intracellular fragment of murine Notch-1 as capable of rendering thymomas resistant to glucocorticoid-induced apoptosis. This effect was confirmed in other T cell lines and in

Michael L Deftos; Ethan W Ojala; Michael J Bevan

1998-01-01

43

Signal processing in 2 dimensional Doppler echocardiography  

Microsoft Academic Search

Summary Blood flow recordings made by 2 dimensional Doppler echocardiography can sometimes be understood more easily than conventional Doppler recordings, because of the anatomical 2 dimensional presentation. In contrast, signal processing has become more complicated and requires more explanation. In 2 dimensional Doppler echocardiography the analog ultrasonic signal received by the transducer is converted into an audible signal, which next

Hans Bot; Ben J. Delemarre; Cees A. Visser; Arend J. Dunning

1987-01-01

44

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

45

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

46

Improved television signal processing system  

NASA Technical Reports Server (NTRS)

Digital system processes spacecraft television pictures by converting images sensed on a photostorage vidicon to pulses which can be transmitted by telemetry. This system can be applied in the processing of medical X ray photographs and in electron microscopy.

Wong, R. Y.

1967-01-01

47

Cross-frequency Temporal Envelope Correlation in Complex Auditory Signals: Preliminary Investigations.  

E-print Network

modulated signals between spectral channels. When 2 to 5 sine-wave modu- lated narrow-band signals that the auditory system is able to process mon- aural envelope correlation, at least with a small number of sine-wave by several American-English speakers in a quiet environment. The TI-Digits sound files are digitized at 20 k

Paris-Sud XI, Université de

48

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 on a computer before implementing it in analog hardware. 1 #12;Broadcasting: television and radio programs the depth. On the other hand, radars make use of radio waves in order to communicate the locations

Chen, Ying "Ada"

49

Automatic generation of signal processing integrated circuits  

Microsoft Academic Search

A system for the automated design of signal processing integrated circuits is described in this thesis. The system is based on a library of circuit cells, and a software package that can configure the cells into complete integrated circuits. The architecture of the cell library is optimized for low and medium bandwidth digital signal processing applications. Circuits designed with the

Pope

1985-01-01

50

Optical signal processing in Radar systems  

Microsoft Academic Search

Opto-electronic components and their performances are well suited to be integrated in radar systems. In this paper, two optical architectures illustrate functions that are specific to optical processing of microwave signals, i.e., time-delay-based processing and arbitrary waveform generation of large frequency bandwidth signals.

Sylvie Tonda-Goldstein; Daniel Dolfi; Aymeric Monsterleet; Stéphane Formont; Jean Chazelas; Jean-Pierre Huignard

2006-01-01

51

INTERACTIVE EC-BASED SIGNAL PROCESSING  

Microsoft Academic Search

We introduce new types of signal processing for which the characteristics of the signal processing filters are designed automatically by interactive evolutionary computation (IEC) based on human perception, such as hearing or vision. We first describe our existing works that use this approach, such as recovering distorted speech and hearing-aid fitting, as well as other related works in this field.

Hideyuki Takagi; Norimasa Hayashida

52

Signal processing system in cavity enhanced spectroscopy  

NASA Astrophysics Data System (ADS)

The paper presents a signal processing system used for nitrogen dioxide detection employing cavity enhanced absorption spectroscopy. In this system, the absorbing gas concentration is determined by the measurement of a decay time of a light pulse trapped in a cavity. The setup includes a resonance optical cavity, which was equipped with spherical and high reflectance mirrors, the pulsed diode laser (414 nm) and electronic signal processing system. In order to ensure registration of low-level signals and accurate decay time measurements, special preamplifier and digital signal processing circuit were developed. Theoretical analyses of main parameters of optical cavity and signal processing system were presented and especially signal-to-noise ratio was taken into consideration. Furthermore, investigation of S/N signal processing system and influence of preamplifier feedback resistance on the useful signal distortion were described. The aim of the experiment was to study potential application of cavity enhanced absorption spectroscopy for construction of fully optoelectronic NO2 sensor which could replace, e.g., commonly used chemical detectors. Thanks to the developed signal processing system, detection limit of NO2 sensor reaches the value of 0.2 ppb (absorption coefficient equivalent = 2.8 × 10-9 cm-1).

Wojtas, J.; Bielecki, Z.

2008-12-01

53

Multifractal Fourier detrended cross-correlation analysis of traffic signals  

NASA Astrophysics Data System (ADS)

Multifractal detrended cross-correlation analysis (MF-DXA) has been developed to detect the long-range power-law cross-correlation of considered signals in the presence of non-stationarity. However, crossovers arising from extrinsic periodic trends make the scaling behavior difficult to analyze. We introduce a Fourier filtering method to eliminate the trend effects and systematically investigate the multifractal cross-correlation of simulated and real traffic signals. The crossover locations are found approximately corresponding to the periods of underlying trend. Traffic velocity on one road and flows on adjacent roads show strong cross-correlation. They also present weak multifractality after periodic trends are removed. The traffic velocity and flow are cross-correlated in opposite directions which is accordant to their actual evolution.

Zhao, Xiaojun; Shang, Pengjian; Lin, Aijing; Chen, Gang

2011-10-01

54

A coherent nonlinear optical signal induced by electron correlations  

PubMed Central

The correlated behavior of electrons determines the structure and optical properties of molecules, semiconductors, and other systems. Valuable information on these correlations is provided by measuring the response to femtosecond laser pulses, which probe the very short time period during which the excited particles remain correlated. The interpretation of four-wave-mixing techniques, commonly used to study the energy levels and dynamics of many-electron systems, is complicated by many competing effects and overlapping resonances. Here we propose a coherent optical technique, specifically designed to provide a background-free probe for electronic correlations in many-electron systems. The proposed signal pulse is generated only when the electrons are correlated, which gives rise to an extraordinary sensitivity. The peak pattern in two-dimensional plots, obtained by displaying the signal versus two frequencies conjugated to two pulse delays, provides a direct visualization and specific signatures of the many-electron wave functions. PMID:18081382

Mukamel, Shaul; Oszwaldowski, Rafal; Yang, Lijun

2010-01-01

55

Timing control and signal processing design of the MOPITT instrument  

NASA Astrophysics Data System (ADS)

The MOPITT instrument operates on the principle of correlation spectroscopy where the incoming signal is modulated by gas filter and chopper mechanisms and synchronously demodulated within the signal processing system. The performance and flexibility required by the MOPITT instrument resulted in the development of a novel timing control and signal processing design. This design synchronizes modulation and demodulation from a central programmable timing control unit. The data collection system performs a highly linear sigma-delta analog-to-digital conversion prior to signal demodulation. The demodulation operation includes data averaging which reduces the sampled signal bandwidth and extends the signal to noise ratio of the data to in excess of the analog-to-digital converter's rated 16-bit dynamic range.

Henry, Dennis; Hackett, John P.; Drummond, James R.; Colley, Roger

2002-02-01

56

CONTROL, COMMUNICATION & SIGNAL PROCESSING (CCSP)  

E-print Network

RESEARCH AREAS · Communication networks · Image and video processing · Computer vision · Identification; computer vision of robotic systems; medical imaging & remote sensing; radar & sonar imaging; digital image & Computer Engineering B.S. Manjunath: image processing; computer vision; neural networks; multimedia

Akhmedov, Azer

57

Signal processing methods for MFE plasma diagnostics  

SciTech Connect

The application of various signal processing methods to extract energy storage information from plasma diamagnetism sensors occurring during physics experiments on the Tandom Mirror Experiment-Upgrade (TMX-U) is discussed. We show how these processing techniques can be used to decrease the uncertainty in the corresponding sensor measurements. The algorithms suggested are implemented using SIG, an interactive signal processing package developed at LLNL.

Candy, J.V.; Casper, T.; Kane, R.

1985-02-01

58

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

59

Introduction to Video Signal Processing  

E-print Network

, speech, image, graphics, and video. 4 #12;Multimedia A multimedia system integrates more than one media-based. All kinds of media such as voice, texts, video, pictures, graphics can be transmitted and processed-way (synchronous) applications: smart phones (MMS), video conferencing, distance learning, interactive games

Yang, Shih-Hsuan

60

Signal processing for sound capture  

Microsoft Academic Search

High-quality electret microphones and single-chip processo rs are economical enough to be used in large numbers. This latitude opens opportunities for dynamic source location and sound capture with spatial selectivity in three dimensions. This report discusses algorithms for matched-filter processing of microphone arrays and for coordinate tracking of moving talkers. A pr ototype conferencing system is demonstrated in which the

Daniel V. Rabinkin; Richard J. Renomeron; Atul Sharma; James L. Flanagan

1998-01-01

61

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

62

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

63

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

64

Using Many-Core Hardware to Correlate Radio Astronomy Signals  

E-print Network

Using Many-Core Hardware to Correlate Radio Astronomy Signals Rob V. van Nieuwpoort nieuwpoort@astron.nl John W. Romein romein@astron.nl ASTRON, Netherlands Institute for Radio Astronomy, Dwingeloo, The Netherlands ABSTRACT A recent development in radio astronomy is to replace traditional dishes with many small

van Nieuwpoort, Rob V.

65

Uncertainty, fuzzy logic, and signal processing  

Microsoft Academic Search

In this paper we focus on model-based statistical signal processing and how some problems that are associated with it can be solved using fuzzy logic. We explain how uncertainty (which is prevalent in statistical signal processing applications) can be handled within the framework of fuzzy logic. Type-1 singleton and non-singleton fuzzy logic systems (FLSs) are reviewed. Type-2 FLSs, which are

Jerry M. Mendel

2000-01-01

66

The Behavioral Neuroscience of Anuran Social Signal Processing  

PubMed Central

Acoustic communication is the major component of social behavior in anuran amphibians (frogs and toads) and has served as a neuroethological model for the nervous system’s processing of social signals related to mate choice decisions. The male’s advertisement or mating call is its most conspicuous social signal, and the nervous system’s analysis of the call is a progressive process. As processing proceeds through neural systems, response properties become more specific to the signal and, in addition, neural activity gradually shifts from representing sensory (auditory periphery and brainstem) to sensorimotor (diencephalon) to motor (forebrain) components of a behavioral response. A comparative analysis of many anuran species shows that the first stage in biasing responses toward conspecific signals over heterospecific signals, and toward particular features of conspecific signals, lies in the tuning of the peripheral auditory system. Biases in processing signals are apparent through the brainstem auditory system, where additional feature detection neurons are added by the time processing reaches the level of the midbrain. Recent work using immediate early gene expression as a marker of neural activity suggests that by the level of the midbrain and forebrain, the differential neural representation of conspecific and heterospecific signals involves both changes in mean activity levels across multiple subnuclei, and in the functional correlations among acoustically active areas. Our data show that in frogs the auditory midbrain appears to play an important role in controlling behavioral responses to acoustic social signals by acting as a regulatory gateway between the stimulus analysis of the brainstem and the behavioral and physiological control centers of the forebrain. We predict that this will hold true for other vertebrate groups such as birds and fish that produce acoustic social signals, and perhaps also in fish where electroreception or vibratory sensing through the lateral line systems plays a role in social signaling, as in all these cases ascending sensory information converges onto midbrain nuclei which relay information to higher brain centers. PMID:20863685

Wilczynski, Walter; Ryan, Michael J.

2010-01-01

67

The behavioral neuroscience of anuran social signal processing.  

PubMed

Acoustic communication is the major component of social behavior in anuran amphibians (frogs and toads) and has served as a neuroethological model for the nervous system's processing of social signals related to mate choice decisions. The male's advertisement or mating call is its most conspicuous social signal, and the nervous system's analysis of the call is a progressive process. As processing proceeds through neural systems, response properties become more specific to the signal and, in addition, neural activity gradually shifts from representing sensory (auditory periphery and brainstem) to sensorimotor (diencephalon) to motor (forebrain) components of a behavioral response. A comparative analysis of many anuran species shows that the first stage in biasing responses toward conspecific signals over heterospecific signals, and toward particular features of conspecific signals, lies in the tuning of the peripheral auditory system. Biases in processing signals are apparent through the brainstem auditory system, where additional feature detection neurons are added by the time processing reaches the level of the midbrain. Recent work using immediate early gene expression as a marker of neural activity suggests that by the level of the midbrain and forebrain, the differential neural representation of conspecific and heterospecific signals involves both changes in mean activity levels across multiple subnuclei, and in the functional correlations among acoustically active areas. Our data show that in frogs the auditory midbrain appears to play an important role in controlling behavioral responses to acoustic social signals by acting as a regulatory gateway between the stimulus analysis of the brainstem and the behavioral and physiological control centers of the forebrain. We predict that this will hold true for other vertebrate groups such as birds and fish that produce acoustic social signals, and perhaps also in fish where electroreception or vibratory sensing through the lateral line systems plays a role in social signaling, as in all these cases ascending sensory information converges onto midbrain nuclei which relay information to higher brain centers. PMID:20863685

Wilczynski, Walter; Ryan, Michael J

2010-12-01

68

Correlation between Correlations Process and Time in Quantum Networks  

E-print Network

We study a special inhomogeneous quantum network consisting of a ring of M pseudospins (here M = 4) sequentially coupled to one and the same central spin under the influence of given pulse sequences (quantum gate operations). This architecture could be visualized as a quantum Turing machine with a cyclic ``tape''. Rather than input-output-relations we investigate the resulting process, i.e. the correlation between one- and two-point expectation values (``correlations'') over various time-steps. The resulting spatio-temporal pattern exhibits many non-classical features including Zeno-effects, violation of temporal Bell-inequalities, and quantum parallelism. Due to the strange web of correlations being built-up, specific measurement outcomes for the tape may refer to one or several preparation histories of the head. Specific families of correlation functions are more stable with respect to dissipation than the total wavefunction.

Mahler, G; Kim, Ilki

1998-01-01

69

Sonar signal processing using probabilistic signal and ocean environmental models.  

PubMed

Acoustic signals propagating through the ocean are refracted, scattered, and attenuated by the ocean volume and boundaries. Many aspects of how the ocean affects acoustic propagation are understood, such that the characteristics of a received signal can often be predicted with some degree of certainty. However, acoustic ocean parameters vary with time and location in a manner that is not, and cannot be, precisely known; some uncertainty will always remain. For this reason, the characteristics of the received signal can never be precisely predicted and must be described in probabilistic terms. A signal processing structure recently developed relies on knowledge of the ocean environment to predict the statistical characteristics of the received signal, and incorporates this description into the processor in order to detect and classify targets. Acoustic measurements at 250 Hz from the 1996 Strait of Gibraltar Acoustic Monitoring Experiment are used to illustrate how the processor utilizes environmental data to classify source depth and to underscore the importance of environmental model fidelity and completeness. PMID:19206791

Culver, R Lee; Camin, H John

2008-12-01

70

Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals  

PubMed Central

The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN) signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network. PMID:22454576

Perez, Isaac Ramos; Bosch-Lluis, Xavi; Camps, Adriano; Alvarez, Nereida Rodriguez; Hernandez, Juan Fernando Marchan; Domenech, Enric Valencia; Vernich, Carlos; de la Rosa, Sonia; Pantoja, Sebastian

2009-01-01

71

Calibration of correlation radiometers using pseudo-random noise signals.  

PubMed

The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers' outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called "baseline errors" associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN) signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver's output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network. PMID:22454576

Pérez, Isaac Ramos; Bosch-Lluis, Xavi; Camps, Adriano; Alvarez, Nereida Rodriguez; Hernandez, Juan Fernando Marchán; Domènech, Enric Valencia; Vernich, Carlos; de la Rosa, Sonia; Pantoja, Sebastián

2009-01-01

72

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

73

Methodological Framework for Estimating the Correlation Dimension in HRV Signals  

PubMed Central

This paper presents a methodological framework for robust estimation of the correlation dimension in HRV signals. It includes (i) a fast algorithm for on-line computation of correlation sums; (ii) log-log curves fitting to a sigmoidal function for robust maximum slope estimation discarding the estimation according to fitting requirements; (iii) three different approaches for linear region slope estimation based on latter point; and (iv) exponential fitting for robust estimation of saturation level of slope series with increasing embedded dimension to finally obtain the correlation dimension estimate. Each approach for slope estimation leads to a correlation dimension estimate, called D^2, D^2?, and D^2max. D^2 and D^2max estimate the theoretical value of correlation dimension for the Lorenz attractor with relative error of 4%, and D^2? with 1%. The three approaches are applied to HRV signals of pregnant women before spinal anesthesia for cesarean delivery in order to identify patients at risk for hypotension. D^2 keeps the 81% of accuracy previously described in the literature while D^2? and D^2max approaches reach 91% of accuracy in the same database. PMID:24592284

Bolea, Juan; Laguna, Pablo; Remartinez, Jose Maria; Rovira, Eva; Navarro, Augusto; Bailon, Raquel

2014-01-01

74

The inclusion process: duality and correlation inequalities  

E-print Network

We prove a comparison inequality between a system of independent random walkers and a system of random walkers which either interact by attracting each other -- a process which we call here the symmetric inclusion process (SIP) -- or repel each other -- a generalized version of the well-known symmetric exclusion process. As an application, new correlation inequalities are obtained for the SIP, as well as for some interacting diffusions which are used as models of heat conduction, -- the so-called Brownian momentum process, and the Brownian energy process. These inequalities are counterparts of the inequalities (in the opposite direction) for the symmetric exclusion process, showing that the SIP is a natural bosonic analogue of the symmetric exclusion process, which is fermionic. Finally, we consider a boundary driven version of the SIP for which we prove duality and then obtain correlation inequalities.

C. Giardina; F. Redig; K. Vafayi

2009-06-25

75

Wavelength-domain RF photonic signal processing  

NASA Astrophysics Data System (ADS)

This thesis presents a novel approach to RF-photonic signal processing applications based on wavelength-domain optical signal processing techniques using broadband light sources as the information carriers, such as femtosecond lasers and white light sources. The wavelength dimension of the broadband light sources adds an additional degree of freedom to conventional optical signal processing systems. Two novel wavelength-domain optical signal processing systems are presented and demonstrated in this thesis. The first wavelength-domain RF photonic signal processing system is a wavelength-compensated squint-free photonic multiple beam-forming system for wideband RF phased-array antennas. Such a photonic beam-forming system employs a new modulation scheme developed in this thesis, which uses traveling-wave tunable filters to modulate wideband RF signals onto broadband optical light sources in a frequency-mapped manner. The wavelength dimension of the broadband light sources provides an additional dimension in the wavelength-compensated Fourier beam-forming system for mapping the received RF frequencies to the linearly proportional optical frequencies, enabling true-time-delay beam forming, as well as other novel RF-photonic signal processing functions such as tunable filtering and frequency down conversion. A new slow-light mechanism, the SLUGGISH light, has also been discovered with an effective slow-light velocity of 86 m/s and a record time-bandwidth product of 20. Experimental demonstration of true-time-delay beam forming based on the SLUGGISH light effect has also been presented in this thesis. In the second wavelength-domain RF photonic signal processing system, the wavelength dimension increases the information carrying capacity by spectrally multiplexing multiple wavelength channels in a wavelength-division-multiplexing fiber-optic communication system. A novel ultrafast all-optical 3R (Re-amplification, Retiming, Re-shaping) wavelength converter based on interactions between (3+1)-D optical solitons has been developed and demonstrated numerically in this thesis, which can exchange information between different wavelength channels and enhance the network maneuverability. Dispersion management for the generation of (3+1)-D optical solitons using a pair of negative dispersive mirrors is proposed and demonstrated. An ultrafast all-optical wavelength converter based on the dragging interaction between light bullets with different colors is presented, which features a compact size of 100mumx 100mumx 1mm, an ultra-high conversion speed of over 1 TB/s, and a wavelength conversion range of more than 50 nm.

Gao, Lu

76

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

E-print Network

Ear Modeling and Sound Signal Processing Jack Xin Abstract Ear modeling can significantly improve sound signal processing and the design of hearing devices. Ear models based on mechanics and neu- ral. The PDEs also facilitates an alternative sound amplification method for hearing aid design. Department

Xin, Jack

77

Signalling and phosphorus: correlations between mate signalling effort and body elemental composition in crickets  

E-print Network

composition in crickets SUSAN M. BERTRAM, JOHN D. SCHADE & JAMES J. ELSER School of Life Sciences, Arizona produced by male Texas field crickets, Gryllus texensis. Signalling was strongly and positively correlated crickets reared on high-protein diets (45% protein) showed significantly greater nymphal survival, faster

Elser, Jim

78

Performance evaluation system of signal processing algorithms  

Microsoft Academic Search

Signal processing algorithms (SPA) play a key role in an imaging IR tracker which is widely used in infrared search and track (IRST) system. When being used to target detection, recognition and tracking, SPA has a significant influence on the performance of the IRST system. Due to the variety and complexity of field scenes and countermeasures, SPA should be robust

Shike Huang; Lijuan Li; Baoguo Chen; Zhenyu Wang

2001-01-01

79

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

80

System identification techniques for adaptive signal processing  

Microsoft Academic Search

Many problems in adaptive filtering can be approached from the point of view of system identification. The close interconnection between these two disciplines is explored in some detail. This approach makes it possible to apply recursive parameter estimation algorithms to adaptive signal processing. Several examples are discussed including: adaptive line enhancement, generalized adaptive noise cancelling, adaptive deconvolution and adaptive TDOA

Benjamin Friedlander

1982-01-01

81

Scaling radio astronomy signal correlation on heterogeneous supercomputers using variousdata distribution methodologies  

NASA Astrophysics Data System (ADS)

Next generation radio telescopes will require orders of magnitude more computing power to provide a view of the universe with greater sensitivity. In the initial stages of the signal processing flow of a radio telescope, signal correlation is one of the largest challenges in terms of handling huge data throughput and intensive computations. We implemented a GPU cluster based software correlator with various data distribution models and give a systematic comparison based on testing results obtained using the Fornax supercomputer. By analyzing the scalability and throughput of each model, optimal approaches are identified across a wide range of problem sizes, covering the scale of next generation telescopes.

Wang, Ruonan; Harris, Christopher

2013-12-01

82

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

83

Research on Signal Processing Algorithms in GPS Receivers  

NASA Astrophysics Data System (ADS)

The modern standard satellite navigation receivers are commonly based on ASICs for signal processing and fast microprocessors for application calculations. The software satellite navigation receiver is also developed in recent years. The research on software receivers becomes one trend of satellite navigation receiver. For algorithms on signal processing play an important role in satellite navigation receivers, the paper illuminates the signal processing algorithms in detail. The GPS receiver is widely used at present. So the paper places emphasis on signal processing algorithms about GPS receiver. Signal processing algorithms include three aspects: the algorithm on signal acquisition, the algorithm on carrier tracking and the algorithm on PRN (pseudo random noise) code tracking. In the part of signal acquisition, the method of using FFT to get the result of circular correlation is introduced. The paper carefully researches the method and discusses the derivation process of the method. In the part of carrier tracking, the paper describes the principle of frequency locked loop (FLL) and phase locked loop (PLL) and analyzes the principle of loop filter. The method of transition from s-domain to z-domain is introduced. The computation of noise bandwidth of the loop filter are expatiated and the structures of one-step digital loop filter, two-step digital loop filter and three step are given. Other parameters of loop filters are also given. In the part of code tracking, delay-early locked loop (DLL) is introduced. Theoretical analysis and experiment results demonstrate the algorithms in the paper. Through the simulation testing, the performance of combination of PLL and FLL can be acknowledged.

Cai, Fan; Yin, Yan; Zhang, Xiu-Zhong

2007-03-01

84

Processing Electromyographic Signals to Recognize Words  

NASA Technical Reports Server (NTRS)

A recently invented speech-recognition method applies to words that are articulated by means of the tongue and throat muscles but are otherwise not voiced or, at most, are spoken sotto voce. This method could satisfy a need for speech recognition under circumstances in which normal audible speech is difficult, poses a hazard, is disturbing to listeners, or compromises privacy. The method could also be used to augment traditional speech recognition by providing an additional source of information about articulator activity. The method can be characterized as intermediate between (1) conventional speech recognition through processing of voice sounds and (2) a method, not yet developed, of processing electroencephalographic signals to extract unspoken words directly from thoughts. This method involves computational processing of digitized electromyographic (EMG) signals from muscle innervation acquired by surface electrodes under a subject's chin near the tongue and on the side of the subject s throat near the larynx. After preprocessing, digitization, and feature extraction, EMG signals are processed by a neural-network pattern classifier, implemented in software, that performs the bulk of the recognition task as described.

Jorgensen, C. C.; Lee, D. D.

2009-01-01

85

A correlation polarimeter for noise-like signals. [optimum estimation of linearly polarized electromagnetic wave  

NASA Technical Reports Server (NTRS)

Optimum estimation (tracking) of the polarization plane of a linearly polarized electromagnetic wave is determined when the signal is a narrow-band Gaussian random process with a polarization plane angle which is also a Gaussian random process. This model is compared to previous work and is applicable to space communication. The estimator performs a correlation operation similar to an amplitude-comparison monopulse angle tracker, giving the name correlation polarimeter. Under large signal-to-noise ratio (SNR), the estimator is causal. Performance of the causal correlation polarimeter is evaluated for arbitrary SNR. Optimum precorrelation filtering is determined. With low SNR, the performance of this system is far better than that of previously developed systems. Practical implementation is discussed. A scheme is given to reduce the effect of linearly polarized noise.

Ohlson, J. E.

1976-01-01

86

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

87

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

88

Source and processing effects on noise correlations  

NASA Astrophysics Data System (ADS)

We quantify the effects of spatially heterogeneous noise sources and seismic processing on noise correlation measurements and their sensitivity to Earth structure. Using numerical wavefield simulations and adjoint techniques, we calculate interstation correlations and sensitivity kernels for arbitrarily distributed noise sources where-as in the real Earth-different frequencies are generated in different locations. While both heterogeneous noise sources and processing can have profound effects on noise correlation waveforms, narrow-band traveltime measurements are less affected, in accord with previous analytical studies. Sensitivities to Earth structure depend strongly on the source distribution and the processing scheme, and they reveal exotic frequency dependencies that go beyond the well-known frequency scaling of the Fresnel zone width. Our results indicate that modern full waveform inversion applied to noise correlations is not possible unless one of the following measures is taken: (1) properly account for noise source distribution and processing, or (2) limit measurements to phase or time shifts in narrow frequency bands. Failure to do so can lead to erroneous misfits, tomographic artefacts, and reduced resolution.

Fichtner, Andreas

2014-06-01

89

Performance evaluation system of signal processing algorithms  

NASA Astrophysics Data System (ADS)

Signal processing algorithms (SPA) play a key role in an imaging IR tracker which is widely used in infrared search and track (IRST) system. When being used to target detection, recognition and tracking, SPA has a significant influence on the performance of the IRST system. Due to the variety and complexity of field scenes and countermeasures, SPA should be robust enough for military use. The question arises as to how to measure and assess the performance of SPA efficiently and properly. On the other hand, the study on SPA performance evaluation will not only give an assessment to a specific algorithm, but also help the development of signal processing technology. In this paper we propose a way to set up an evaluating system in the SPA research laboratory and study the criteria for the evaluation.

Huang, Shike; Li, Lijuan; Chen, Baoguo; Wang, Zhenyu

2001-09-01

90

Macrocell design for concurrent signal processing  

SciTech Connect

Macrocells serve as subsystems at the top level of the hardware design hierarchy. The authors present the macrocell design technique as applied to the implementation of real-time, sampled-data signal processing functions. The design of such circuits is particularly challenging due to the computationally intensive nature of signal-processing algorithms and the constraints of real-time operation. The most efficient designs make use of a high degree of concurrency-a property facilitated by the microcell approach. Two circuit projects whose development resulted largely from the macrocell methodology described are used as examples throughout the report: a linear-predictive vocoder circuit, and a front-end filter-bank chip for a speech recognition system. Both are monolithic multiprocessor implementations: the lpc vocoder circuit contains three processors, the filter-bank chip two processors. 10 references.

Pope, S.P.; Brodersen, R.W.

1983-01-01

91

Signal Processing for Underwater Acoustic Communications  

Microsoft Academic Search

The performance and complexity of signal processing systems for underwater acoustic communications has dramatically increased over the last two decades. With its origins in non-coherent modulation and detection for communication at rates under 100 bits per second, phase-coherent digital communication systems employing multi- channel adaptive equalization with explicit symbol-timing and phase tracking are being deployed in commercial and military systems

Suleyman S. Kozat; Jill K. Nelson; Andrew C. Singer

92

Digital signal processing for beam position feedback  

SciTech Connect

Stabilization of the particle beam position with respect to the focusing optics in the third generation synchrotron light sources is crucial to achieving low emittance and high brightness. For this purpose, global and local beam orbit correction feedbacks will be implemented in the APS storage ring. In this article, the authors discuss application of digital signal processing to particle/photon beam position feedback using the PID (proportional, integral, and derivative) control algorithm.

Chung, Y.; Emery, L.; Kirchman, J.

1992-04-01

93

Optical fiber delay-line signal processing  

Microsoft Academic Search

Single-mode optical fiber is an attractive delay medium for processing microwave frequency signals due to its extremely low loss (less than 0.1 dB\\/microsec) and large available time-bandwidth product (in excess of 100,000). Progress in the efficient tapping of light from single-mode fibers has made it possible to construct recirculating and nonrecirculating (tapped) delay-line structures that can perform a variety of

K. P. Jackson; B. Moslehi; C. C. Cutler; J. W. Goodman; H. J. Shaw; S. A. Newton; M. Tur

1985-01-01

94

Signal processing system in cavity enhanced spectroscopy  

Microsoft Academic Search

The paper presents a signal processing system used for nitrogen dioxide detection employing cavity enhanced absorption spectroscopy.\\u000a In this system, the absorbing gas concentration is determined by the measurement of a decay time of a light pulse trapped\\u000a in a cavity.\\u000a \\u000a The setup includes a resonance optical cavity, which was equipped with spherical and high reflectance mirrors, the pulsed\\u000a diode

J. Wojtas; Z. Bielecki

2008-01-01

95

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

96

NOVEL SIGNAL PROCESSING WITH NONLINEAR TRANSMISSION LINES  

SciTech Connect

Nonlinear dielectrics offer uniquely strong and tunable nonlinearities that make them attractive for current devices (for example, frequency-agile microwave filters) and for future signal-processing technologies. The goal of this project is to understand pulse propagation on nonlinear coplanar waveguide prototype devices. We have performed time-domain and frequency-domain experimental studies of simple waveguide structures and pursued a theoretical understanding of the propagation of signals on these nonlinear waveguides. To realistically assess the potential applications, we used a time-domain measurement and analysis technique developed during this project to perform a broadband electrodynamics characterization in terms of nonlinear, dispersive, and dissipative effects. We completed a comprehensive study of coplanar waveguides made from high-temperature superconducting thin-film YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} electrodes on nonlinear dielectric single-crystal SrTiO{sub 3} substrates. By using parameters determined from small-signal (linear) transmission characteristics of the waveguides, we develop a model equation that successfully predicts and describes large-signal (nonlinear) behavior.

D. REAGOR; ET AL

2000-08-01

97

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

98

STARCON: a reconfigurable fieldable signal-processing system  

NASA Astrophysics Data System (ADS)

Conventional fieldable signal processing systems utilize custom hardware manufactured and configured specifically for a single signal processing application. Developing new systems or reconfiguring existing systems involves great expense and time expenditure. We at Alliant Techsystems have developed a signal processing system based on commercially available hardware which is completely software programmable and yet small and fast enough to be used in fieldable multisensor signal processing applications. This paper will discuss Alliant's reconfigurable signal processing system.

Brandt, Scott A.; Budenske, John

1991-04-01

99

Automatic generation of signal processing integrated circuits  

SciTech Connect

A system for the automated design of signal processing integrated circuits is described in this thesis. The system is based on a library of circuit cells, and a software package that can configure the cells into complete integrated circuits. The architecture of the cell library is optimized for low and medium bandwidth digital signal processing applications. Circuits designed with the system use a multiprocessor architecture. Input to the system is a design file written in a specialized programming language. Software emulation from the design file is used to verify performance. A two-pass silicon compiler is used to translate the design file into a mask-level description of an integrated circuit. A major goal of the project is to make the system useable by those with little or no formal training in integrated circuits. A second goal is to reduce the time and cost associated with performing an integrated circuit design, while still producing designs which are reasonably efficient in their use of the technology. Development of the system was guided by basic research on appropriate architectures and circuit constructs for signal processors. As part of this research an integrated circuit was designed which performs speech analysis and synthesis. This vocoder circuit is intended for use in low-bit-rate digital speech transmission systems.

Pope, S.P.

1985-01-01

100

An intelligent, onboard signal processing payload concept  

SciTech Connect

Our approach to onboard processing will enable a quicker return and improved quality of processed data from small, remote-sensing satellites. We describe an intelligent payload concept which processes RF lightning signal data onboard the spacecraft in a power-aware manner. Presently, onboard processing is severely curtailed due to the conventional management of limited resources and power-unaware payload designs. Delays of days to weeks are commonly experienced before raw data is received, processed into a human-usable format, and finally transmitted to the end-user. We enable this resource-critical technology of onboard processing through the concept of Algorithm Power Modulation (APM). APM is a decision process used to execute a specific software algorithm, from a suite of possible algorithms, to make the best use of the available power. The suite of software algorithms chosen for our application is intended to reduce the probability of false alarms through postprocessing. Each algorithm however also has a cost in energy usage. A heuristic decision tree procedure is used which selects an algorithm based on the available power, time allocated, algorithm priority, and algorithm performance. We demonstrate our approach to power-aware onboard processing through a preliminary software simulation.

Shriver, P. M. (Patrick M.); Harikumar, J. (Jayashree); Briles, S. C. (Scott C.); Gokhale, M. (Maya)

2003-01-01

101

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

102

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

103

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

104

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

105

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

106

Digital signal processing using virtual instruments  

NASA Astrophysics Data System (ADS)

The area of test and measurement is changing rapidly because of the recent developments in software and hardware. The test and measurement systems are increasingly becoming PC based. Most of these PC based systems use graphical programming language to design test and measurement modules called virtual instruments (Vis). These Vis provide visual representation of dat or models, and make understanding of abstract concepts and algorithms easier. This allows users to express their ideas in a concise manner. One such virtual instruments package is LabVIEW from National Instruments Corporation at Austin, Texas. This software package is one of the first graphical programming products and is currently used in number of academic institutions, industries, Department of Defense graphical programming products and is currently sued in number of academic institutions, industries, Department of Defense, Department of Energy, and National Aeronautics and Space Administration for various test, measurement, and control applications. LabVIEW has an extensive built-in VI library that can be used to design and develop solutions for different applications. Besides using the built-in VI library that can be used to design and develop solutions for different applications. Besides using the built-in VI modules in LabVIEW, the user can design new VI modules easily. This paper discusses the use of LabVIEW to design and develop digital signal processing VI modules such as Fourier Analysis and Windowing. Instructors can use these modules to teach some of the signal processing concepts effectively.

Anderson, James A.; Korrapati, Raghu; Swain, Nikunja K.

2000-08-01

107

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

108

Active voltammetric microsensors with neural signal processing  

NASA Astrophysics Data System (ADS)

Many industrial and environmental processes, including bioremediation, would benefit from the feedback and control information provided by a local multi-analyte chemical sensor. For most processes, such a sensor would need to be rugged enough to be placed in situ for long-term remote monitoring, and inexpensive enough to be fielded in useful numbers. The multi-analyte capability is difficult to obtain from common passive sensors, but can be provided by an active device that produces a spectrum-type response. Such new active gas microsensor technology has been developed at Argonne National Laboratory. The technology couples an electrocatalytic ceramic-metallic (cermet) microsensor with a voltammetric measurement technique and advanced neural signal processing. It has been demonstrated to be flexible, rugged, and very economical to produce and deploy. Both narrow interest detectors and wide spectrum instruments have been developed around this technology. Much of this technology's strength lies in the active measurement technique employed. The technique involves applying voltammetry to a miniature electrocatalytic cell to produce unique chemical 'signatures' from the analytes. These signatures are processed with neural pattern recognition algorithms to identify and quantify the components in the analyte. The neural signal processing allows for innovative sampling and analysis strategies to be employed with the microsensor. In most situations, the whole response signature from the voltammogram can be used to identify, classify, and quantify an analyte, without dissecting it into component parts. This allows an instrument to be calibrated once for a specific gas or mixture of gases by simple exposure to a multi-component standard rather than by a series of individual gases. The sampled unknown analytes can vary in composition or in concentration; the calibration, sensing, and processing methods of these active voltammetric microsensors can detect, recognize, and quantify different signatures and support subsequent analyses. The instrument can be trained to recognize and report expected analyte components (within some tolerance), but also can alarm when unexpected components are detected. Unknowns can be repeat-sampled to build a reference library for later post processing and verification.

Vogt, Michael C.; Skubal, Laura R.

1999-02-01

109

Active voltammetric microsensors with neural signal processing.  

SciTech Connect

Many industrial and environmental processes, including bioremediation, would benefit from the feedback and control information provided by a local multi-analyte chemical sensor. For most processes, such a sensor would need to be rugged enough to be placed in situ for long-term remote monitoring, and inexpensive enough to be fielded in useful numbers. The multi-analyte capability is difficult to obtain from common passive sensors, but can be provided by an active device that produces a spectrum-type response. Such new active gas microsensor technology has been developed at Argonne National Laboratory. The technology couples an electrocatalytic ceramic-metallic (cermet) microsensor with a voltammetric measurement technique and advanced neural signal processing. It has been demonstrated to be flexible, rugged, and very economical to produce and deploy. Both narrow interest detectors and wide spectrum instruments have been developed around this technology. Much of this technology's strength lies in the active measurement technique employed. The technique involves applying voltammetry to a miniature electrocatalytic cell to produce unique chemical ''signatures'' from the analytes. These signatures are processed with neural pattern recognition algorithms to identify and quantify the components in the analyte. The neural signal processing allows for innovative sampling and analysis strategies to be employed with the microsensor. In most situations, the whole response signature from the voltammogram can be used to identify, classify, and quantify an analyte, without dissecting it into component parts. This allows an instrument to be calibrated once for a specific gas or mixture of gases by simple exposure to a multi-component standard rather than by a series of individual gases. The sampled unknown analytes can vary in composition or in concentration, the calibration, sensing, and processing methods of these active voltammetric microsensors can detect, recognize, and quantify different signatures and support subsequent analyses. The instrument can be trained to recognize and report expected analyte components (within some tolerance), but also can alarm when unexpected components are detected. Unknowns can be repeat-sampled to build a reference library for later post processing and verification.

Vogt, M. C.

1998-12-11

110

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.

111

FREQUENCY-BASED SIGNAL PROCESSING FOR ULTRASOUND COLOR FLOW IMAGING  

Microsoft Academic Search

In ultrasound color flow imaging, the computation of flow estimates is well-recognized as a challenging problem from a signal processing perspective. The flow visualization performance of this imaging tool is often affected by error sources such as the lack of abundant signal samples available for processing, the presence of wideband clutter in the acquired signals, and the flow signal distortions

Alfred C. H. Yu; K. Wayne Johnston; Richard S. C. Cobbold

2007-01-01

112

Polarization vector signal processing for radar clutter suppression  

NASA Astrophysics Data System (ADS)

The statistical model of a radar scatterer illuminated and observed on one channel is extended to suit the two-channel polarization case, accounting for statistical range and Doppler-spread characteristics. The mathematical formulation for the polarization-sensitive scatterer was written in the framework of a random process scattering matrix whose covariance properties took on a sixteen-element tensor of the fourth rank. Each element is expressed in terms of its correlation with respect to range and Doppler; this tensor contained all the backscatter data needed for determining the range/time/polarization-dependent behavior of the received signal for any arbitrary transit polarized waveform.

Vannicola, V. C.; Lis, S.

113

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

114

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

115

Adaptive Signal Processing Testbed: Software design specification  

NASA Astrophysics Data System (ADS)

The Adaptive Signal Processing Testbed is a system for the analysis and characterization of adaptive filtering algorithms used for the excision of interfering tones from direct sequence spread spectrum communications systems. The design specification for the software to be developed for this testbed is described. The testbed system is divided into a number of subsystems and the required software for each subsystem is presented. The control and data flow between the subsystem as well as a modular breakdown of the software is provided. The online component of the host software provides all the control, monitoring, and storage functions for the embedded software system that resides on the bus in the host computer, a Sun workstation. The online component consists of five separate modules: user interface, graphical display, central processing, data storage, and development. The offline, or post-processing, component of the host software provides sophisticated statistical and spectral analysis of the data stored on disk. An interactive environment is provided for the user to develop customized analysis methods.

Parliament, Hugh A.

1990-06-01

116

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

117

Correlation analysis for abnormal ECG signal features extraction  

Microsoft Academic Search

This work investigates the use of signal analysis technique to extract the important features from the 12 lead system (electrocardiogram) ECG signal. The real ECG signals used in this study were obtained from the Selangor Medical Center and also downloaded from the Internet resources. Lead II is chosen for the whole analysis due to it representative characteristics for identifying the

Alias Bin Ramli; Putri Aidawati Ahmad

2003-01-01

118

TWO-DIMENSIONAL COMPRESSION OF SURFACE ELECTROMYOGRAPHIC SIGNALS USING COLUMN-CORRELATION SORTING AND IMAGE ENCODERS  

E-print Network

of Computer Science. chaffim@gmail.com INTRODUCTION Surface Electromyographic (S-EMG) signals are importantTWO-DIMENSIONAL COMPRESSION OF SURFACE ELECTROMYOGRAPHIC SIGNALS USING COLUMN-CORRELATION SORTING for compression of S-EMG signals, by segmenting the S-EMG signal and arranging the segments as columns of a 2D

Carvalho, João Luiz

119

Signal processing and feature extraction toolbox for prognosis\\/diagnosis  

Microsoft Academic Search

In this paper we describe a novel general toolbox that we have developed as part of the integrated prognosis and diagnosis framework. This tool can be used to select the appropriate signal processing techniques for enhancing a signal, to select a portion of a signal, to represent a signal in 2 dimensional domains such as the time-frequency, to extract appropriate

Shubha Kadambe

2005-01-01

120

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

121

Multi-microphone correlation-based processing for robust speech recognition  

Microsoft Academic Search

A novel method of signal processing for robust speech recognition using multiple microphones is presented. The method, loosely based on the human binaural hearing system, consists of passing the speech signals detected by multiple microphones through bandpass filtering and nonlinear rectification operations, and then cross-correlating the outputs from each channel within each frequency band. These operations provide an estimate of

Thomas M. Sullivan; Richard M. Stern

1993-01-01

122

Design of hardware correlator for BOC(1,1) baseband signal  

NASA Astrophysics Data System (ADS)

BOC signal structure was introduced in this paper. BOC signal modulation and BOC(1,1) auto-correlation function were analyzed in detail. Based on the signal acquisition, tracking loop for BOC(1,1), a hardware design with FPGA chip was presented for the correlator, implemented using EP2S60 from Altera Co. The hardware correlator architecture and functions were described with two key modules, i.e. Pseudo-Random Noise (PRN) code generator and Numerical Control Oscillator(NCO). The practical test results show that the designed hardware correlator can work steadily and correctly, which is valid for the BOC(1,1) signal acquisition and tracking.

Yang, Dong-Kai; Li, Wei-Qiang; Liu, Xian-Yang; Feng, Yuan

2009-12-01

123

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

2014-05-28

124

Optimal signal processing for continuous qubit readout  

NASA Astrophysics Data System (ADS)

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 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? calculus. Our method is applicable to multihypothesis 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.

Ng, Shilin; Tsang, Mankei

2014-08-01

125

Closed orbit feedback with digital signal processing  

SciTech Connect

The closed orbit feedback experiment conducted on the SPEAR using the singular value decomposition (SVD) technique and digital signal processing (DSP) is presented. The beam response matrix, defined as beam motion at beam position monitor (BPM) locations per unit kick by corrector magnets, was measured and then analyzed using SVD. Ten BPMs, sixteen correctors, and the eight largest SVD eigenvalues were used for closed orbit correction. The maximum sampling frequency for the closed loop feedback was measured at 37 Hz. Using the proportional and integral (PI) control algorithm with the gains Kp = 3 and K{sub I} = 0.05 and the open-loop bandwidth corresponding to 1% of the sampling frequency, a correction bandwidth ({minus}3 dB) of approximately 0.8 Hz was achieved. Time domain measurements showed that the response time of the closed loop feedback system for 1/e decay was approximately 0.25 second. This result implies {approximately} 100 Hz correction bandwidth for the planned beam position feedback system for the Advanced Photon Source storage ring with the projected 4-kHz sampling frequency.

Chung, Y.; Kirchman, J.; Lenkszus, F. [and others

1994-08-01

126

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

127

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

128

Springer.com Handbook of Signal Processing Systems  

E-print Network

by William S. Levine (2) Digital Signal Processing in Home Entertainment by Konstantinos Konstantinides by Keshab K. Parhi and Yanni Chen (2) Systolic Arrays by Yu Hen Hu and S.Y. Kung (3) Decidable Signal

Bhattacharyya, Shuvra S.

129

Overview of seismic signal processing equipment and procedures  

SciTech Connect

The report provides a brief overview of the automatic data processing equipment (ADPE) and procedures used for processing seismic signals. The discussion includes basic information on the seismic recording systems and stations; a brief description of hardware, hardware configurations, and software; data formats; processing techniques used to convert seismic signals to computer-compatible format; and basic procedures for analysis of the processed signals. 8 refs., 8 figs., 2 tabs.

Igusa, T.; Lum, P.K.W.

1986-01-01

130

Wavelet-based statistical signal processing using hidden Markov models  

Microsoft Academic Search

Wavelet-based statistical signal processing techniques such as denoising and detection typically model the wavelet coefficients as independent or jointly Gaussian. These models are unrealistic for many real-world signals. We develop a new framework for statistical signal processing based on wavelet-domain hidden Markov models (HMMs) that concisely models the statistical dependencies and non-Gaussian statistics encountered in real-world signals. Wavelet-domain HMMs are

Matthew S. Crouse; Robert D. Nowak; Richard G. Baraniuk

1998-01-01

131

Microwave signal processing with photorefractive dynamic holography  

NASA Astrophysics Data System (ADS)

Have you ever found yourself listening to the music playing from the closest stereo rather than to the bromidic (uninspiring) person speaking to you? Your ears receive information from two sources but your brain listens to only one. What if your cell phone could distinguish among signals sharing the same bandwidth too? There would be no "full" channels to stop you from placing or receiving a call. This thesis presents a nonlinear optical circuit capable of distinguishing uncorrelated signals that have overlapping temporal bandwidths. This so called autotuning filter is the size of a U.S. quarter dollar and requires less than 3 mW of optical power to operate. It is basically an oscillator in which the losses are compensated with dynamic holographic gain. The combination of two photorefractive crystals in the resonator governs the filter's winner-take-all dynamics through signal-competition for gain. This physical circuit extracts what is mathematically referred to as the largest principal component of its spatio-temporal input space. The circuit's practicality is demonstrated by its incorporation in an RF-photonic system. An unknown mixture of unknown microwave signals, received by an antenna array, constitutes the input to the system. The output electronically returns one of the original microwave signals. The front-end of the system down converts the 10 GHz microwave signals and amplifies them before the signals phase modulate optical beams. The optical carrier is suppressed from these beams so that it may not be considered as a signal itself to the autotuning filter. The suppression is achieved with two-beam coupling in a single photorefractive crystal. The filter extracts the more intense of the signals present on the carrier-suppressed input beams. The detection of the extracted signal restores the microwave signal to an electronic form. The system, without the receiving antenna array, is packaged in a 13 x 18 x 6? briefcase. Its power consumption equals that of a regular 50 W household light bulb. The system was shipped to different parts of the country for real-time demonstrations of signal separation thus also validating its claim to robustness.

Fotheringham, Edeline B.

132

Signal processing for passive detection and classification of underwater acoustic signals  

NASA Astrophysics Data System (ADS)

This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship spectra and were measured at distances up to 7 km. The combination of cross-correlation and DEMON methods allows separation of the acoustic signatures of ships in busy urban environments. Finally, we consider the extension of this algorithm for vessel tracking using phase measurement of the DEMON signal recorded by two or more hydrophones. Tests conducted in the Hudson River and NY Bay confirmed opportunity of Direction of Arrival (DOA) funding using the phase DEMON method.

Chung, Kil Woo

133

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

134

Optimizing signal and image processing applications using Intel libraries  

NASA Astrophysics Data System (ADS)

This paper presents optimized signal and image processing libraries from Intel Corporation. Intel Performance Primitives (IPP) is a low-level signal and image processing library developed by Intel Corporation to optimize code on Intel processors. Open Computer Vision library (OpenCV) is a high-level library dedicated to computer vision tasks. This article describes the use of both libraries to build flexible and efficient signal and image processing applications.

Landré, Jérôme; Truchetet, Frédéric

2007-01-01

135

Multifractal detrended cross-correlation analysis for two nonstationary signals  

NASA Astrophysics Data System (ADS)

We propose a method called multifractal detrended cross-correlation analysis to investigate the multifractal behaviors in the power-law cross-correlations between two time series or higher-dimensional quantities recorded simultaneously, which can be applied to diverse complex systems such as turbulence, finance, ecology, physiology, geophysics, and so on. The method is validated with cross-correlated one- and two-dimensional binomial measures and multifractal random walks. As an example, we illustrate the method by analyzing two financial time series.

Zhou, Wei-Xing

2008-06-01

136

Signal processing experiments with the LEGO MINDSTORMS NXT kit for use in signals and systems courses  

Microsoft Academic Search

This paper presents a set of inexpensive signal processing experiments that can be used as projects or hands-on demos to supplement signals and systems courses. Signals and systems concepts tend to be very mathematical and abstract, and students who prefer more practical material are at a disadvantage in these courses. The experiments are performed on the LEGO MINDSTORMS NXT platform,

Bonnie Heck Ferri; Safayet Ahmed; Jennifer E. Michaels; Eric Dean; Chris Garyet; Sam Shearman

2009-01-01

137

Field cross correlator for analysis of ultrafast signals.  

PubMed

The cross-correlation function between two light fields is recorded with the help of a new device. The proposed correlator exhibits ultrashort time resolution. The optical path difference between the two interfering beams does not have to be known with interferometric precision. The experimental dynamic range proved to be as large as 10(5). The device features imaging capabilities that could be applied to the analysis of two-dimensional images with ultrashort time resolution. PMID:20963013

Dou, K; Débarre, A; Gouët, J L; Lorgeré; Tchénio, P

1994-12-01

138

Mixed analog-digital correlator using sigma-delta and multirate processing techniques  

Microsoft Academic Search

Describes a mixed analog-digital solution for designing correlators with continuous-time input signals which employs a combination of sigma-delta and multirate processing techniques. Such an architecture can overcome the major limitations of purely analog circuits and still achieve the attractive objectives of low power consumption and small chip size which cannot be afforded using purely digital signal processing techniques together with

Jorge Grilo; J. E. Franca

1991-01-01

139

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

140

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

141

Effects of coarse-graining on the scaling behavior of long-range correlated and anti-correlated signals  

PubMed Central

We investigate how various coarse-graining (signal quantization) methods affect the scaling properties of long-range power-law correlated and anti-correlated signals, quantified by the detrended fluctuation analysis. Specifically, for coarse-graining in the magnitude of a signal, we consider (i) the Floor, (ii) the Symmetry and (iii) the Centro-Symmetry coarse-graining methods. We find that for anti-correlated signals coarse-graining in the magnitude leads to a crossover to random behavior at large scales, and that with increasing the width of the coarse-graining partition interval ?, this crossover moves to intermediate and small scales. In contrast, the scaling of positively correlated signals is less affected by the coarse-graining, with no observable changes when ? < 1, while for ? > 1 a crossover appears at small scales and moves to intermediate and large scales with increasing ?. For very rough coarse-graining (? > 3) based on the Floor and Symmetry methods, the position of the crossover stabilizes, in contrast to the Centro-Symmetry method where the crossover continuously moves across scales and leads to a random behavior at all scales; thus indicating a much stronger effect of the Centro-Symmetry compared to the Floor and the Symmetry method. For coarse-graining in time, where data points are averaged in non-overlapping time windows, we find that the scaling for both anti-correlated and positively correlated signals is practically preserved. The results of our simulations are useful for the correct interpretation of the correlation and scaling properties of symbolic sequences.

Xu, Yinlin; Ma, Qianli D.Y.; Schmitt, Daniel T.; Bernaola-Galvan, Pedro; Ivanov, Plamen Ch.

2014-01-01

142

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

143

Digital signal processing in the radio science stability analyzer  

NASA Technical Reports Server (NTRS)

The Telecommunications Division has built a stability analyzer for testing Deep Space Network installations during flight radio science experiments. The low-frequency part of the analyzer operates by digitizing wave signals with bandwidths between 80 Hz and 45 kHz. Processed outputs include spectra of signal, phase, amplitude, and differential phase; time series of the same quantities; and Allan deviation of phase and differential phase. This article documents the digital signal-processing methods programmed into the analyzer.

Greenhall, C. A.

1995-01-01

144

Control and signal processing by transcriptional interference  

PubMed Central

A transcriptional activator can suppress gene expression by interfering with transcription initiated by another activator. Transcriptional interference has been increasingly recognized as a regulatory mechanism of gene expression. The signals received by the two antagonistically acting activators are combined by the polymerase trafficking along the DNA. We have designed a dual-control genetic system in yeast to explore this antagonism systematically. Antagonism by an upstream activator bears the hallmarks of competitive inhibition, whereas a downstream activator inhibits gene expression non-competitively. When gene expression is induced weakly, the antagonistic activator can have a positive effect and can even trigger paradoxical activation. Equilibrium and non-equilibrium models of transcription shed light on the mechanism by which interference converts signals, and reveals that self-antagonism of activators imitates the behavior of feed-forward loops. Indeed, a synthetic circuit generates a bell-shaped response, so that the induction of expression is limited to a narrow range of the input signal. The identification of conserved regulatory principles of interference will help to predict the transcriptional response of genes in their genomic context. PMID:19690569

Buetti-Dinh, Antoine; Ungricht, Rosemarie; Kelemen, Janos Z; Shetty, Chetak; Ratna, Prasuna; Becskei, Attila

2009-01-01

145

An exactly solvable correlated stochastic process in finite time  

NASA Astrophysics Data System (ADS)

We propose a correlated stochastic process of which the novel non-Gaussian probability mass function is constructed by exactly solving moment generating function. The calculation of cumulants and auto-correlation shows that the process is convergent and scale invariant in the large but finite time limit. We demonstrate that the model infers the correlation strength in a discrete correlated time-series data, and predicts the data distribution with high precision in the finite time regime.

Kim, Jongwook; Jo, Junghyo

2014-07-01

146

Digital signal processing utilizing a generic instruction set  

Microsoft Academic Search

In order to maintain a degree of technological equivalence between software and hardware in advanced VLSI development efforts, a set of generic instructions has been defined in the form of Ada-callable procedures which invoke a complex sequence of events for the execution of vector instructions in signal processing modules. Attention is presently given to real time signal processing functions in

V. V. W. Mosley; J. Bronder; A. Wenk

1984-01-01

147

Statistical signal processing using wavelet-domain hidden Markov models  

NASA Astrophysics Data System (ADS)

Most wavelet-based statistical signal and image processing techniques treat the wavelet coefficients as though they were statistically independent. This assumption is unrealistic; considering the statistical dependencies between wavelet coefficients can yield substantial performance improvements. In this paper, we develop a new framework for wavelet-based signal processing that employs hidden Markov models to characterize the dependencies between wavelet coefficients.

Crouse, Matthew S.; Nowak, Robert D.; Baraniuk, Richard G.

1997-10-01

148

Statistical signal processing using wavelet-domain hidden Markov models  

Microsoft Academic Search

Most wavelet-based statistical signal and image processing techniques treat the wavelet coefficients as though they were statistically independent. This assumption is unrealistic; considering the statistical dependencies between wavelet coefficients can yield substantial performance improvements. In this paper, we develop a new framework for wavelet-based signal processing that employs hidden Markov models to characterize the dependencies between wavelet coefficients.

Matthew S. Crouse; Robert D. Nowak; Richard G. Baraniuk

1997-01-01

149

Signal processing for AUV based interferometric synthetic aperture sonar  

Microsoft Academic Search

This paper presents signal processing techniques particularly suited for interferometric Synthetic Aperture Sonar (SAS) systems onboard Autonomous Underwater Vehicles (AUV) (or other platforms carrying high grade navigation systems). The signal processing is applied to data collected in a controlled rail experiment at Elba Island, Italy, using a wideband interferometric SAS and an Inertial Navigation System (INS). We evaluate different strategies

Roy Edgar Hansen; T. O. Saebo; Kenneth Gade; Sean Chapman

2003-01-01

150

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing  

E-print Network

) for scalable and energy-efficient data aggregation (this aggrega- tion process is called collaborative signal. Instead of each source node sending sensory data to its sink for aggregation (the so-called client) for collaborative signal and information processing, which considerably reduces the sensory data traffic and query

151

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

152

Some signal-processing issues in radar-target identification  

NASA Astrophysics Data System (ADS)

Three issues in radar target identification are discussed: (1) the performance characteristics of Prony-like signal processing for estimating EM features, from the viewpoint of an input-output information transformation; (2) pole (and singularity) sets of EM features obtained from computed EM data for several situations; (3) some initial results of using frequency domain poles for target identification. It is demonstrated for data similar to that which occurs in sampling EM fields, that Prony's Method seems to preserve information, that give poles values whose accuracy on the average equals the accuracy of the input data. However, the imaginary (oscillation) components are almost always found with greater accuracy than the real (decay) components, whose accuracy seems more closely correlated to that of the predictor coefficients. The richness of the pole-based representation for EM problems is shown by giving sample results from transient data, linear-array patterns, and plane wave scattering from a half space. Finally, various target identification schemes using frequency domain poles is compared as a function of signal to noise level, with the tentative finding that improved performance seems to occur at the expense of increased computational effort.

Miller, E. K.

1982-09-01

153

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

154

Signal processing techniques in genomic engineering  

Microsoft Academic Search

Now that the human genome has been sequenced, the measurement, processing, and analysis of specific genomic information in real time are gaining considerable interest because of their importance to better the understanding of the inherent genomic function, the early diagnosis of disease, and the discovery of new drugs. Traditional methods to process and analyze deoxyribonucleic acid (DNA) or ribonucleic acid

Xin-Yun Zhang; Fei Chen; Yuan-Ting Zhang; SHANNON C. AGNER; METIN AKAY; Zu-Hong Lu; M. M. Y. Waye; S. K.-W. Tsui

2002-01-01

155

[Detrended cross-correlation analysis: a new method for gait signal analysis].  

PubMed

The cross-correlation of gait signal can mirror the health situations of different people. It is important to analyze the long-range cross correlations of the two signals of nonstationarity for medical research. In this paper, we propose a detrended cross-correlation analysis (DCCA) method for analyzing the different gait signal in physiological and pathological conditions. Our work dealt with three kinds of gait signals, including those of normal young people (23 to 29 years of age), those of healthy old people (71 to 77 years of age) and those of the old people (60 to 77 years of age) with Parkinson's disease from the MIT-BIH database. We carried out the DCCA for the three gait signals of nonstationarity. The results showed that the self-similarity of gait signal got more unstable with the age increasing and health status worsening. From the cross-correlation analysis, we found that the cross-correlation degree of gait signal of young people increased gradually, the healthy old people changed slowly and the Parkinson's disease patients showed unstable changes. We can make medical diagnosis and treatment according to the differences among different gait signals. PMID:23469555

Wang, Pingping; Wang, Jun

2012-12-01

156

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

157

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

158

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

E-print Network

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 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. The SNR metrics and corresponding models presented herein are expanded to be applicable to both standard and filtered correlations. 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 ...

Xue, Zhenyu; Vlachos, Pavlos P

2014-01-01

159

Integrate-and-fire neurons with threshold noise: A tractable model of how interspike interval correlations affect neuronal signal transmission  

NASA Astrophysics Data System (ADS)

Many neurons exhibit interval correlations in the absence of input signals. We study the influence of these intrinsic interval correlations of model neurons on their signal transmission properties. For this purpose, we employ two simple firing models, one of which generates a renewal process, while the other leads to a nonrenewal process with negative interval correlations. Different methods to solve for spectral statistics in the presence of a weak stimulus (spike train power spectra, cross spectra, and coherence functions) are presented, and their range of validity is discussed. Using these analytical results, we explore a lower bound on the mutual information rate between output spike train and input stimulus as a function of the system’s parameters. We demonstrate that negative correlations in the baseline activity can lead to enhanced information transfer of a weak signal by means of noise shaping of the background noise spectrum. We also show that an enhancement is not compulsory—for a stimulus with power exclusively at high frequencies, the renewal model can transfer more information than the nonrenewal model does. We discuss the application of our analytical results to other problems in neuroscience. Our results are also relevant to the general problem of how a signal affects the power spectrum of a nonlinear stochastic system.

Lindner, Benjamin; Chacron, Maurice J.; Longtin, André

2005-08-01

160

Assess Sleep Stage by Modern Signal Processing Techniques  

E-print Network

In this paper, two modern adaptive signal processing techniques, Empirical Intrinsic Geometry and Synchrosqueezing transform, are applied to quantify different dynamical features of the respiratory and electroencephalographic signals. We show that the proposed features are theoretically rigorously supported, as well as capture the sleep information hidden inside the signals. The features are used as input to multiclass support vector machines with the radial basis function to automatically classify sleep stages. The effectiveness of the classification based on the proposed features is shown to be comparable to human expert classification -- the proposed classification of awake, REM, N1, N2 and N3 sleeping stages based on the respiratory signal (resp. respiratory and EEG signals) has the overall accuracy $81.7\\%$ (resp. $89.3\\%$) in the relatively normal subject group. In addition, by examining the combination of the respiratory signal with the electroencephalographic signal, we conclude that the respiratory s...

Wu, Hau-tieng; Lo, Yu-Lun

2014-01-01

161

Digital signal processing based on inverse scattering transform.  

PubMed

Through numerical modeling, we illustrate the possibility of a new approach to digital signal processing in coherent optical communications based on the application of the so-called inverse scattering transform. Considering without loss of generality a fiber link with normal dispersion and quadrature phase shift keying signal modulation, we demonstrate how an initial information pattern can be recovered (without direct backward propagation) through the calculation of nonlinear spectral data of the received optical signal. PMID:24321955

Turitsyna, Elena G; Turitsyn, Sergei K

2013-10-15

162

An introduction to engineering with signal processing  

Microsoft Academic Search

Engineers of the 21st century will work in an environment that will require a variety of skills that include not only traditional engineering topics but that also includes more emphasis on topics such as communications, teamwork, the design\\/process\\/manufacture steps for taking a concept to a product, and combining the techno-scientific base with a societal context. This paper discusses a pilot

Delores M. Etter

1994-01-01

163

Adaptive parametric algorithms for processing coherent Doppler-lidar signal  

Microsoft Academic Search

The authors study the autoregressive and moving average (ARMA) filter for lidar signal processing. After a short presentation of the atmospheric laser Doppler instrument project (ALADIN), they introduce the objective of this paper, which is to extract the Doppler frequency and to retrieve the spectral width of a noised lidar signal. A general presentation of ARMA filters and parametric adaptive

Jean-Luc Zarader; Alain Dabas; Pierre H. Flamant; Bruno Gas; Olivier Adam

1999-01-01

164

Signal Processing and Communication An Overview for Prospective Students  

E-print Network

, wind, solar, heat · Energy distribution · Energy storage ­ smart batteries Computer Systems & NetworksSignal Processing and Communication An Overview for Prospective Students http · Analog, digital, and microwave circuits · Mixed-signal ICs #12;Power Systems · Energy conversion ­ hydro

Schniter, Philip

165

Biomedical signal acquisition, processing and transmission using smartphone  

Microsoft Academic Search

This article describes technical aspects involved in the programming of a system of acquisition, processing and transmission of biomedical signals by using mobile devices. This task is aligned with the permanent development of new technologies for the diagnosis and sickness treatment, based on the feasibility of measuring continuously different variables as electrocardiographic signals, blood pressure, oxygen concentration, pulse or simply

Pablo Roncagliolo; Luis Arredondo; Agustín González

2007-01-01

166

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 to control stem cell fate. Keywords stem cells, systems biology, signaling networks, extrinsic control Curr. Zandstra Purpose of review Strategies to manipulate stem cells for therapeutic applications are limited

Zandstra, Peter W.

167

ABET Course Syllabus Spring 2011 Introduction to Digital Signal Processing  

E-print Network

students with: o Understanding of the theory of A/D and D/A signal conversion, digital filtering will be able to: 1) Understand how the combination of A/D conversion, digital filtering, and D/A conversion may the roles of downsampling and upsampling in digital processing of analog signals. 6) Understand

168

Introduction to Digital Signal Processing ENG EC416 (Spring 2013)  

E-print Network

/D conversion, digital filtering, and D/A conversion may be used to filter analog signals such as speech conversion, digital filtering and spectral analysis. o Experience in the design and implementation of digital in digital processing of analog signals. 6) Understand the respective roles of the magnitude and phase

169

Evolving Signal Processing for BrainComputer Interfaces  

E-print Network

INVITED P A P E R Evolving Signal Processing for Brain­Computer Interfaces This paper discusses electrical signals from the human brain, automat- ed systems for assessing changes in user cognitive state, intent, and response to events are of increasing interest. Brain­ computer interface (BCI) systems can

Makeig, Scott

170

On correlation analysis of bivariate alarm signals Zijiang Yang and Jiandong Wang.  

E-print Network

@ece.ualberta.ca Abstract-- This paper studies the correlation analysis for bivariate alarm signals in order to indicate and distribution of the correlation delay. An industrial case study is provided to illustrate the proposed sequential alarms and unneces- sary operations. Yang et al. [12] generated pseudo continuous time series from

Wang, Jiandong

171

Time-resolved laser Doppler and phase Doppler signal processing  

NASA Astrophysics Data System (ADS)

Signal processing in Laser Doppler Anemometry (LDA) and Phase Anemometry (PDA) is carried out in both, the time domain, for instance by counter processors, and the frequency domain by processors based on the Fast Fourier Transform (FFT). FFT based signal processing allows a frequency and phase determination even for rather low signal to noise ratios. Nevertheless, the time-varying amplitude, frequency, and phase difference of Doppler bursts contain relevant information which is generally not utilized by conventional signal analysis. By determining the bust envelopes of PDA bursts it is possible to improve the resolution of particle sizing which is restricted to a corresponding phase difference from 0 to 360 degrees when conventional FFT processing is used. Time-resolved phase difference and frequency determination allow an improved signal validation since effects like trajectory effects, particle coincidences within the measuring volume, droplet oscillations or non-spherical particle characteristics can be detected. In this contribution signal processing methods for determining such effects are introduced. Thee methods will offer improved signal processing facilities with respect to the above mentioned topics. Practical applications are demonstrated by simulation and experimental results.

Lehmann, Peter; Wriedt, Thomas; Schoene, Armin

1995-09-01

172

Optical Signal Processing: Poisson Image Restoration and Shearing Interferometry  

NASA Technical Reports Server (NTRS)

Optical signal processing can be performed in either digital or analog systems. Digital computers and coherent optical systems are discussed as they are used in optical signal processing. Topics include: image restoration; phase-object visualization; image contrast reversal; optical computation; image multiplexing; and fabrication of spatial filters. Digital optical data processing deals with restoration of images degraded by signal-dependent noise. When the input data of an image restoration system are the numbers of photoelectrons received from various areas of a photosensitive surface, the data are Poisson distributed with mean values proportional to the illuminance of the incoherently radiating object and background light. Optical signal processing using coherent optical systems is also discussed. Following a brief review of the pertinent details of Ronchi's diffraction grating interferometer, moire effect, carrier-frequency photography, and achromatic holography, two new shearing interferometers based on them are presented. Both interferometers can produce variable shear.

Hong, Yie-Ming

1973-01-01

173

from the editor IEEE SIGNAL PROCESSING MAGAZINE2 SEPTEMBER 2004  

E-print Network

, or tracks the target for a missile to hit; instead they see the phone, TV, and that the missile works have to help ourselves! On second thought, "Signal Processing In- side" might not be so bad. Our humble

Liu, K. J. Ray

174

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

175

All-optical digital-to-analog conversion using pulse pattern recognition based on optical correlation processing  

Microsoft Academic Search

We propose and demonstrate a novel all-optical digital-to-analog (D\\/A) conversion using pulse pattern recognition based on optical correlation processing. It is composed of pulse pattern recognition based on correlation processing and intensity adjustment using an optical attenuator. We obtain a single pulse as a result of pulse pattern recognition by using correlation processing between a target digital signal and a

T. Nishitani; T. Konishi; H. Furukawa; K. Itoh

2005-01-01

176

Forensically Determining the Order of Signal Processing Operations  

E-print Network

Forensically Determining the Order of Signal Processing Operations Matthew C. Stamm #1 , Xiaoyu Chu to identify the use of specific image processing operations and manipulations. These forensic techniques work's processing history. In this paper, we present a framework for forensically deter mining t

Liu, K. J. Ray

177

Optical signal processing for optical packet switching networks  

Microsoft Academic Search

Optical packet switching promises to bring the flexibility and efficiency of the Internet to transparent optical networking with bit rates extending beyond that currently available with electronic router technologies. New optical signal processing techniques have been demonstrated that enable routing at bit rates from 10 Gb\\/s to beyond 40 Gb\\/s. We review these signal processing techniques and how all-optical-wavelength converter

D. J. Blumenthal; J. E. Bowers; L. Rau; Hsu-Feng Chou; S. Rangarajan; Wei Wang; K. N. Poulsen

2003-01-01

178

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; Thevenaz, Luc

2013-01-01

179

HYMOSS signal processing for pushbroom spectral imaging  

NASA Technical Reports Server (NTRS)

The objective of the Pushbroom Spectral Imaging Program was to develop on-focal plane electronics which compensate for detector array non-uniformities. The approach taken was to implement a simple two point calibration algorithm on focal plane which allows for offset and linear gain correction. The key on focal plane features which made this technique feasible was the use of a high quality transimpedance amplifier (TIA) and an analog-to-digital converter for each detector channel. Gain compensation is accomplished by varying the feedback capacitance of the integrate and dump TIA. Offset correction is performed by storing offsets in a special on focal plane offset register and digitally subtracting the offsets from the readout data during the multiplexing operation. A custom integrated circuit was designed, fabricated, and tested on this program which proved that nonuniformity compensated, analog-to-digital converting circuits may be used to read out infrared detectors. Irvine Sensors Corporation (ISC) successfully demonstrated the following innovative on-focal-plane functions that allow for correction of detector non-uniformities. Most of the circuit functions demonstrated on this program are finding their way onto future IC's because of their impact on reduced downstream processing, increased focal plane performance, simplified focal plane control, reduced number of dewar connections, as well as the noise immunity of a digital interface dewar. The potential commercial applications for this integrated circuit are primarily in imaging systems. These imaging systems may be used for: security monitoring systems, manufacturing process monitoring, robotics, and for spectral imaging when used in analytical instrumentation.

Ludwig, David E.

1991-01-01

180

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

181

OPTOELECTRONICS. SIGNAL PROCESSING: Holographic matched filtering of signals in interference sensors made of multimode fiber waveguides  

NASA Astrophysics Data System (ADS)

Theoretical and experimental investigations were made of the processing of signals in interference single-fiber sensors by the method of holographic matched filtering. It was established that the sensitivity of the measurement method is governed by the mode composition of the fiber waveguides. It was found experimentally that introduction of aperture stops into an optical signal processing system can correct characteristics of the measuring devices. A good agreement was obtained between the experimental and calculated data.

Bykovski?, Yu A.; Vitrik, O. B.; Kulchin, Yurii N.; Larkin, A. I.

1990-01-01

182

Correlates of Capture of Attention and Inhibition of Return across Stages of Visual Processing  

Microsoft Academic Search

How do visual signals evolve from early to late stages in sensory processing? We explored this question by examining two neural correlates of spatial attention. The capture of attention and inhibition of return refer to the initial advantage and subsequent disadvantage to respond to a visual target that follows an irrelevant visual cue at the same location. In the intermediate

Jillian H. Fecteau; Douglas P. Munoz

2005-01-01

183

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

184

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

185

Biomedical signal acquisition, processing and transmission using smartphone  

NASA Astrophysics Data System (ADS)

This article describes technical aspects involved in the programming of a system of acquisition, processing and transmission of biomedical signals by using mobile devices. This task is aligned with the permanent development of new technologies for the diagnosis and sickness treatment, based on the feasibility of measuring continuously different variables as electrocardiographic signals, blood pressure, oxygen concentration, pulse or simply temperature. The contribution of this technology is settled on its portability and low cost, which allows its massive use. Specifically this work analyzes the feasibility of acquisition and the processing of signals from a standard smartphone. Work results allow to state that nowadays these equipments have enough processing capacity to execute signals acquisition systems. These systems along with external servers make it possible to imagine a near future where the possibility of making continuous measures of biomedical variables will not be restricted only to hospitals but will also begin to be more frequently used in the daily life and at home.

Roncagliolo, Pablo; Arredondo, Luis; González, Agustín

2007-11-01

186

Simplified signal processing for impedance spectroscopy with spectrally sparse sequences  

NASA Astrophysics Data System (ADS)

Classical method for measurement of the electrical bio-impedance involves excitation with sinusoidal waveform. Sinusoidal excitation at fixed frequency points enables wide variety of signal processing options, most general of them being Fourier transform. Multiplication with two quadrature waveforms at desired frequency could be easily accomplished both in analogue and in digital domains, even simplest quadrature square waves can be considered, which reduces signal processing task in analogue domain to synchronous switching followed by low pass filter, and in digital domain requires only additions. So called spectrally sparse excitation sequences (SSS), which have been recently introduced into bio-impedance measurement domain, are very reasonable choice when simultaneous multifrequency excitation is required. They have many good properties, such as ease of generation and good crest factor compared to similar multisinusoids. Typically, the usage of discrete or fast Fourier transform in signal processing step is considered so far. Usage of simplified methods nevertheless would reduce computational burden, and enable simpler, less costly and less energy hungry signal processing platforms. Accuracy of the measurement with SSS excitation when using different waveforms for quadrature demodulation will be compared in order to evaluate the feasibility of the simplified signal processing. Sigma delta modulated sinusoid (binary signal) is considered to be a good alternative for a synchronous demodulation.

Annus, P.; Land, R.; Reidla, M.; Ojarand, J.; Mughal, Y.; Min, M.

2013-04-01

187

Electrophysiological correlates of stimulus equivalence processes.  

PubMed

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., wrist, corn). For pairs of both types, event-related cortical potentials were recorded during and immediately after the presentation of the second word. The obtained waveforms differentiated these two types of pairs. For the unrelated pairs, the waveforms were significantly more negative about 400 ms after the second word was presented, thus replicating the "N400" phenomenon of the cognitive neuroscience literature. In addition, there was a strong positive-tending wave form difference post-stimulus presentation (peaked at about 500 ms) that also differentiated the unrelated from related stimulus pairs. In Experiment 2, the procedures were extended to study arbitrary stimulus-stimulus relations established via matching-to-sample training. Participants were experimentally naïve adults. Sample stimuli (Set A) were trigrams, and comparison stimuli (Sets B, C, D, E, and F) were nonrepresentative forms. Behavioral tests evaluated potentially emergent equivalence relations (i.e., BD, DF, CE, etc.). All participants exhibited classes consistent with the arbitrary matching training. They were also exposed also to an event-related potential procedure like that used in Experiment 1. Some received the ERP procedure before equivalence tests and some after. Only those participants who received ERP procedures after equivalence tests exhibited robust N400 differentiation initially. The positivity observed in Experiment 1 was absent for all participants. These results support speculations that equivalence tests may provide contextual support for the formation of equivalence classes including those that emerge gradually during testing. PMID:20354602

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

2009-09-01

188

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

NASA Astrophysics Data System (ADS)

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 the time-of-flight. Multi-time delayed correlating method is used to improve the time-of-flight estimation resolution. Experimental results indicate that the digital signal processing methods in this paper can reduce the influence of bad weather conditions, and obtain high range accuracy.

Sun, Zhihui; Deng, Jiahao

2008-12-01

189

Neural Correlates of Processing Negative and Sexually Arousing Pictures  

PubMed Central

Recent work has questioned whether the negativity bias is a distinct component of affective picture processing. The current study was designed to determine whether there are different neural correlates of processing positive and negative pictures using event-related brain potentials. The early posterior negativity and late positive potential were greatest in amplitude for erotic pictures. Partial Least Squares analysis revealed one latent variable that distinguished erotic pictures from neutral and positive pictures and another that differentiated negative pictures from neutral and positive pictures. The effects of orienting task on the neural correlates of processing negative and erotic pictures indicate that affective picture processing is sensitive to both stimulus-driven, and attentional or decision processes. The current data, together with other recent findings from our laboratory, lead to the suggestion that there are distinct neural correlates of processing negative and positive stimuli during affective picture processing. PMID:23029071

Bailey, Kira; West, Robert; Mullaney, Kellie M.

2012-01-01

190

Neural correlates of processing negative and sexually arousing pictures.  

PubMed

Recent work has questioned whether the negativity bias is a distinct component of affective picture processing. The current study was designed to determine whether there are different neural correlates of processing positive and negative pictures using event-related brain potentials. The early posterior negativity and late positive potential were greatest in amplitude for erotic pictures. Partial Least Squares analysis revealed one latent variable that distinguished erotic pictures from neutral and positive pictures and another that differentiated negative pictures from neutral and positive pictures. The effects of orienting task on the neural correlates of processing negative and erotic pictures indicate that affective picture processing is sensitive to both stimulus-driven, and attentional or decision processes. The current data, together with other recent findings from our laboratory, lead to the suggestion that there are distinct neural correlates of processing negative and positive stimuli during affective picture processing. PMID:23029071

Bailey, Kira; West, Robert; Mullaney, Kellie M

2012-01-01

191

An epidemic process mediated by a decaying diffusing signal  

NASA Astrophysics Data System (ADS)

We study a stochastic epidemic model consisting of elements (organisms in a community or cells in tissue) with fixed positions, in which damage or disease is transmitted by diffusing agents ('signals') emitted by infected individuals. The signals decay as well as diffuse; since they are assumed to be produced in large numbers, the signal concentration is treated deterministically. The model, which includes four cellular states (susceptible, transformed, depleted, and removed), admits various interpretations: spread of an infection or infectious disease, or of damage in a tissue in which injured cells may themselves provoke further damage, and as a description of the so-called radiation-induced bystander effect, in which the signals are molecules capable of inducing cell damage and/or death in unirradiated cells. The model exhibits a continuous phase transition between spreading and nonspreading phases. We formulate two mean-field theory (MFT) descriptions of the model, one of which ignores correlations between the cellular state and the signal concentration, and another that treats such correlations in an approximate manner. Monte Carlo simulations of the spread of infection on the square lattice yield values for the critical exponents and the fractal dimension consistent with the dynamic percolation universality class.

Faria, Fernando P.; Dickman, Ronald

2012-06-01

192

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

193

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

194

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

E-print Network

, for taking me in as a research student and guiding me in this process with so much enthusiasm and support. vi NOMENCLATURE A/D Analog-to-Digital D/A Digital-to-Analog DSK Digital Signal Processing Starter Kit DSP Digital Signal Processing EVM... .................................................................. 4 Real-time DSP design considerations ............................................. 4 Motivation ....................................................................................... 6 Organization of the thesis...

Jagielski, Christopher

2012-04-24

195

Statistical Signal Processing for Radionuclide Alfred O. Hero  

E-print Network

with MRI/CT side information 5. Bounds and feasibility studies 1 #12;9 Single Photon Emission Computed: Lesions in left cortex #12;scintillator gamma rays pre-processing and control electronics 1st position nthStatistical Signal Processing for Radionuclide Tomography Alfred O. Hero Depts. EECS and Bio

Hero, Alfred O.

196

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing  

E-print Network

, Article ID 850265, 13 pages doi:10.1155/2010/850265 Research Article Vector-Sensor Array Processing signals received on a vector-sensor array. The proposed technique is based on wavefields separation range of applications where vector sensor antennas technology is involved such as seismic processing

Boyer, Edmond

197

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

198

Integrated Optics for Planar imaging and Optical Signal Processing  

NASA Astrophysics Data System (ADS)

Silicon photonics is a subject of growing interest with the potential of delivering planar electro-optical devices with chip scale integration. Silicon-on-insulator (SOI) technology has provided a marvelous platform for photonics industry because of its advantages in integration capability in CMOS circuit and countless nonlinearity applications in optical signal processing. This thesis is focused on the investigation of planar imaging techniques on SOI platform and potential applications in ultra-fast optical signal processing. In the first part, a general review and background introduction about integrated photonics circuit and planar imaging technique are provided. In chapter 2, planar imaging platform is realized by a silicon photodiode on SOI chip. Silicon photodiode on waveguide provides a high numerical aperture for an imaging transceiver pixel. An erbium doped Y2O3 particle is excited by 1550nm Laser and the fluorescent image is obtained with assistance of the scanning system. Fluorescence image is reconstructed by using image de-convolution technique. Under photovoltaic mode, we use an on-chip photodiode and an external PIN photodiode to realize similar resolution as 5?m. In chapter 3, a time stretching technique is developed to a spatial domain to realize a 2D imaging system as an ultrafast imaging tool. The system is evaluated based on theoretical calculation. The experimental results are shown for a verification of system capability to imaging a micron size particle or a finger print. Meanwhile, dynamic information for a moving object is also achieved by correlation algorithm. In chapter 4, the optical leaky wave antenna based on SOI waveguide has been utilized for imaging applications and extensive numerical studied has been conducted. and the theoretical explanation is supported by leaky wave theory. The highly directive radiation has been obtained from the broadside with 15.7 dB directivity and a 3dB beam width of ?Ø 3dB ? 1.65° in free space environment when ? -1 = 2.409 × 105/m, ?=4.576 ×103/m. At the end, electronics beam-steering principle has been studied and the comprehensive model has been built to explain carrier transformation behavior in a PIN junction as individual silicon perturbation. Results show that 1019/cm3 is possible obtained with electron injection mechanism. Although the radiation modulation based on carrier injection of 1019/cm3 gives 0.5dB variation, resonant structure, such as Fabry Perrot Cavity, can be integrated with LOWAs to enhance modulation effect.

Song, Qi

199

Queueing up for enzymatic processing: correlated signaling through coupled degradation  

E-print Network

the observed network connections is critical for the further development of systems and synthetic biology. Here queueing using a synthetic biology application, in which two independent synthetic networks demonstrate 2011; doi:10.1038/msb.2011.94 Subject Categories: metabolic & regulatory networks; synthetic biology

200

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

201

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

202

The development of a cognitive process-oriented correlation model  

E-print Network

THE DEVELOPMENT OF A COGNITIVE PROCESS-ORIENTED CORRELATION MODEL A Thesis by RICHARD JAMES KNEUVEN Submitted to the Office of Graduate Studies of Texas AIIM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1988 Major Subject: Curriculum and Instruction THE DEVELOPMENT OF A COGNITIVE PROCESS-ORIENTED CORRELATION MODEL A Thesis by RICHARD JAMES KNEUVEN Approved as to style and content by: P r c'a exander ( r of Committee ) David...

Kneuven, Richard James

2012-06-07

203

Analog CMOS Implementation of Neural Network for Adaptive Signal Processing  

Microsoft Academic Search

A modular analog CMOS artificial neural network is designed and fabricated for adaptive signal processing. A modified Gilbert multiplier is used as a linear combination of several input signals. Modified back-propagation continuous-time learning rules are used as an adaptive algorithm. The adaptive algorithm adjusts the weights in real time by on-chip learning circuits. Hardware learning circuits are simulated using PSPICE,

Oh Hwa-joon; Fathi M. A. Salam

1994-01-01

204

GNSS-based bistatic SAR: a signal processing view  

NASA Astrophysics Data System (ADS)

This article presents signal processing algorithms used as a new remote sensing tool, that is passive bistatic SAR with navigation satellites (e.g. GPS, GLONASS or Galileo) as transmitters of opportunity. Signal synchronisation and image formation algorithms are described for two system variants: one where the receiver is moving and one where it is fixed on the ground. The applicability and functionality of the algorithms described is demonstrated through experimental imagery that ultimately confirms the feasibility of the overall technology.

Antoniou, Michail; Cherniakov, Mikhail

2013-12-01

205

Digital processing of RF signals from optical frequency combs  

NASA Astrophysics Data System (ADS)

The presented work is focused on digital processing of beat note signals from a femtosecond optical frequency comb. The levels of mixing products of single spectral components of the comb with CW laser sources are usually very low compared to products of mixing all the comb components together. RF counters are more likely to measure the frequency of the strongest spectral component rather than a weak beat note. Proposed experimental digital signal processing system solves this problem by analyzing the whole spectrum of the output RF signal and using software defined radio (SDR) algorithms. Our efforts concentrate in two main areas: Firstly, using digital servo-loop techniques for locking free running continuous laser sources on single components of the fs comb spectrum. Secondly, we are experimenting with digital signal processing of the RF beat note spectrum produced by f-2f 1 technique used for assessing the offset and repetition frequencies of the comb, resulting in digital servo-loop stabilization of the fs comb. Software capable of computing and analyzing the beat-note RF spectrums using FFT and peak detection was developed. A SDR algorithm performing phase demodulation on the f- 2f signal is used as a regulation error signal source for a digital phase-locked loop stabilizing the offset frequency of the fs comb.

Cizek, Martin; Smid, Radek; Buchta, Zden?k.; Mikel, B?etislav; Lazar, Josef; Cip, Ond?ej

2013-01-01

206

Quantum Discrete Fourier Transform with Classical Output for Signal Processing  

E-print Network

Discrete Fourier transform (DFT) is the base of modern signal or information processing. 1-Dimensional fast Fourier transform (1D FFT) and 2D FFT have time complexity O(NlogN) and O(N^2logN) respectively. Quantum 1D and 2D DFT algorithms with classical output (1D QDFT and 2D QDFT) are presented in this paper. And quantum algorithm for convolution estimation is also presented in this paper. Compared with FFT, QDFT has two advantages at least. One of advantages is that 1D and 2D QDFT has time complexity O(sqrt(N)) and O(N) respectively. The other advantage is that QDFT can process very long signal sequence at a time. QDFT and quantum convolution demonstrate that quantum signal processing with classical output is possible.

Chao-Yang Pang; Ben-Qiong Hu

2007-06-17

207

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

PubMed

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

208

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; Hyvarinen, Aapo

2013-01-01

209

Phosphorelays provide tunable signal processing capabilities for the cell.  

PubMed

Achieving a complete understanding of cellular signal transduction requires deciphering the relation between structural and biochemical features of a signaling system and the shape of the signal-response relationship it embeds. Using explicit analytical expressions and numerical simulations, we present here this relation for four-layered phosphorelays, which are signaling systems that are ubiquitous in prokaryotes and also found in lower eukaryotes and plants. We derive an analytical expression that relates the shape of the signal-response relationship in a relay to the kinetic rates of forward, reverse phosphorylation and hydrolysis reactions. This reveals a set of mathematical conditions which, when satisfied, dictate the shape of the signal-response relationship. We find that a specific topology also observed in nature can satisfy these conditions in such a way to allow plasticity among hyperbolic and sigmoidal signal-response relationships. Particularly, the shape of the signal-response relationship of this relay topology can be tuned by altering kinetic rates and total protein levels at different parts of the relay. These findings provide an important step towards predicting response dynamics of phosphorelays, and the nature of subsequent physiological responses that they mediate, solely from topological features and few composite measurements; measuring the ratio of reverse and forward phosphorylation rate constants could be sufficient to determine the shape of the signal-response relationship the relay exhibits. Furthermore, they highlight the potential ways in which selective pressures on signal processing could have played a role in the evolution of the observed structural and biochemical characteristic in phosphorelays. PMID:24244132

Kothamachu, Varun B; Feliu, Elisenda; Wiuf, Carsten; Cardelli, Luca; Soyer, Orkun S

2013-01-01

210

Atmospheric Radar Signal Processing using Bivariate Empirical Mode Decomposition  

NASA Astrophysics Data System (ADS)

This paper is based upon the analysis of real-time data collected from the MST radar, NARL, CityplaceGadanki, country-regionIndia. We apply a new method, Bivariate Empirical Mode Decomposition (BEMD), to the complex time series data for estimating the Doppler frequencies and thus find the parameters like zonal (u), meridonal (v) and Vertical Wind speed (w) etc. BEMD is an algorithm for the analysis of multicomponent signals that breaks them down into a number of amplitude and frequency modulated signals, termed as Intrinsic Mode Functions (IMFs), which are basis functions for representing the signal. In a noisy signal, decomposed IMFs are a combination of IMFs of both signal and noise. By comparing with the characteristics of noise-only IMFs, we will remove the noise-dominant IMFs from the noisy signal. We reconstruct the signal with remaining IMFs and thus denoising the signal. Due to the adaptive nature of the basis functions, EMD is ideally suited than any other method like the Spectrogram, Wavelet etc for analyzing nonlinear and non-stationary processes. Initially, we apply BEMD for simulated signals such as Doppler, Bumps etc. under various noise conditions and then apply the same for the radar data. Results have been validated using Global Positioning System Sonde data. Finally, we classify the noise as Gaussian or not associated with the radar signal received form vertical as well as non vertical directions in the higher bins of the atmosphere using different parameters like Skewness, Kurtosis, Negentropy (Syntropy) and incorporating some tests such as Autocorrelation test, Power Spectral Density test, Partial Autocorrelation test.

Sreenivasulu Reddy, Thatiparthi

2012-07-01

211

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

212

Digital signal processing utilizing a generic instruction set  

NASA Astrophysics Data System (ADS)

In order to maintain a degree of technological equivalence between software and hardware in advanced VLSI development efforts, a set of generic instructions has been defined in the form of Ada-callable procedures which invoke a complex sequence of events for the execution of vector instructions in signal processing modules. Attention is presently given to real time signal processing functions in the cases of fighter aircraft fire control radar, passive sonar surveillance, communications systems' FSK demodulation and bit regeneration, and electronic warfare support measures and countermeasures. Generalized examples of each application are given as data flow graphs.

Mosley, V. V. W.; Bronder, J.; Wenk, A.

213

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

214

Modified signal processing method for spot welding monitor system  

NASA Astrophysics Data System (ADS)

The method for resistance spot welding quality detection is becoming a serious problem recently. Aluminum alloy has high-conductivity and good thermal conductivity, which affects the stability of welding quality. In this paper, a spot welding monitor system based on magnetic sensor array technique is designed for welding quality detection. And a new signal processing method called the "W-ICA" algorithm is proposed to separate the object signals. The results show that the spot welding monitor system works well. And the modified W-ICA algorithm can extract the mixing signal validly and provide us the original signal information. The extract results of the magnetic sensor array help us to analysis whether the spot quality is good or bad.

Wang, Rui; Luo, Zhen; Li, Yang; Xuan, Wenbo; Fan, Naifeng

2010-12-01

215

Modified signal processing method for spot welding monitor system  

NASA Astrophysics Data System (ADS)

The method for resistance spot welding quality detection is becoming a serious problem recently. Aluminum alloy has high-conductivity and good thermal conductivity, which affects the stability of welding quality. In this paper, a spot welding monitor system based on magnetic sensor array technique is designed for welding quality detection. And a new signal processing method called the "W-ICA" algorithm is proposed to separate the object signals. The results show that the spot welding monitor system works well. And the modified W-ICA algorithm can extract the mixing signal validly and provide us the original signal information. The extract results of the magnetic sensor array help us to analysis whether the spot quality is good or bad.

Wang, Rui; Luo, Zhen; Li, Yang; Xuan, Wenbo; Fan, Naifeng

2011-05-01

216

Single image dehazing using local adaptive signal processing  

NASA Astrophysics Data System (ADS)

A local adaptive algorithm for single image dehazing is presented. The algorithm is able to estimate a dehazed image from an observed hazed scene by solving an objective function whose parameters are adapted to local statistics of the hazed image inside a moving window. The proposed objective function is based on a trade-off among several local rank order statistics of the dehazed signal and the mean-squared-error between the hazed and dehazed signals. In order to achieve a high-rate signal processing, the proposed algorithm is implemented in a graphics processing unit (GPU) exploiting massive parallelism. Experimental results obtained with a laboratory prototype are presented, discussed, and compared with those results obtained with existing single image dehazing methods in terms of objective metrics and computational complexity.

Valderrama, Jesus A.; Diaz-Ramirez, Victor H.; Kober, Vitaly

2014-09-01

217

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

218

Depth and structural index estimation of 2D magnetic source using correlation coefficient of analytic signal  

NASA Astrophysics Data System (ADS)

We presented using the correlation coefficient of the analytic signal of real data and the analytic signal of synthetic data generated by the assumed source to estimate the structural index and the depth of the source. First, we assumed that the causative sources are located at different locations in the underground and the structural index of the assumed source is changed from 0 to 3, and then we separately compute the correlation coefficients of the analytic signal of the measured data and the analytic signal of the anomaly generated by each assumed source, the correlation coefficient can get the maximum value when the location and structural index of the assumed source are consistent with the real source. We tested the correlation coefficient method on synthetic noise-free and noise-corrupted magnetic anomalies, and the inversion results indicate that the new method can successfully finish the inversion of magnetic data. We also applied it to measured magnetic data, and we obtain the structural index and the location of the source.

Ma, Guoqing; Li, Lili

2013-04-01

219

Separation of a mixture of independent signals using time delayed correlations  

Microsoft Academic Search

The problem of separating n linearly superimposed uncorrelated signals and determining their mixing coefficients is reduced to an eigenvalue problem which involves the simultaneous diagonalization of two symmetric matrices whose elements are measureable time delayed correlation functions. The diagonalization matrix can be determined from a cost function whose number of minima is equal to the number of degenerate solutions. Our

L. Molgedey; H. G. Schuster

1994-01-01

220

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

221

Training Signal Design for Estimation of Correlated MIMO Channels with Colored  

E-print Network

such as the ergodic capacity and outage capacity of a MIMO channel [1] [2] [3]. The mean square error (MSE) is anotherTraining Signal Design for Estimation of Correlated MIMO Channels with Colored Interference Yong-input multiple-output (MIMO) channels in the presence of colored interference. The linear minimum mean square

Hager, William

222

Distributed Detection of A Deterministic Signal in Correlated Gaussian Noise Over MAC  

E-print Network

1 Distributed Detection of A Deterministic Signal in Correlated Gaussian Noise Over MAC Wenjun Li access channel (MAC), which significantly reduces the bandwidth requirement or detection delay. We assume that with a specially-chosen mapping rule, MAC fusion achieves the same asymptotic performance as centralized detection

Dai, Huaiyu

223

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

224

IEEE SIGNAL PROCESSING MAGAZINE [160] SEPTEMBER 2009 [in the SPOTLIGHT  

E-print Network

IEEE SIGNAL PROCESSING MAGAZINE [160] SEPTEMBER 2009 [in the SPOTLIGHT] Digital Object Identifier Depression of 1929, the news media has not only covered daily developments, but it has also discussed its. Indeed, today's finan- cial analysis and risk managers depend on mathematical tools that, at their core

Drakakis, Konstantinos

225

Multimedia Signal Processing for Behavioral Quantification in Neuroscience  

E-print Network

and Computer Vision]: General J.4 [Social and Behavioral Science]: Neuroscience General Terms: ExperimentationMultimedia Signal Processing for Behavioral Quantification in Neuroscience Peter Andrews1 , Sigal of characteristics, ranging from static morphological features, to dynamic behavior. The latter poses challenges

226

SUBMITTED TO IEEE TRANS. ON SIGNAL PROCESSING 1 Fault Identification  

E-print Network

signature matrix, which is the linear transformation matrix applied to the fault vector, is sparse. TSUBMITTED TO IEEE TRANS. ON SIGNAL PROCESSING 1 Fault Identification via Non-parametric Belief a pattern of faults from a set of noisy linear measurements. Unfortunately, maximum a posteriori probability

Anderson, Richard

227

IEEE SIGNAL PROCESSING MAGAZINE [133] SEPTEMBER 2009 [social SCIENCES  

E-print Network

IEEE SIGNAL PROCESSING MAGAZINE [133] SEPTEMBER 2009 [social SCIENCES] Capturing Order in Social Interactions F ollowing Aristotle, "Man is by nature a social animal; an indi- vidual who is unsocial naturally are the perfect machines for social interaction: the muscles of our faces allow the expression of our subtlest

Vinciarelli, Alessandro

228

Keywords: Noncontact, Fast-Fourier Transform, Video Processing, Color Signal  

E-print Network

heartbeats, which can be a sign of anemia, thyroid disease, caffeine and drug use, or other conditions described in this paper uses basic signal processing techniques and a recently devel- oped approach known. Currently, heart rate is often measured with an electrocardiogram (ECG), which uses at least three

Acton, Scott

229

Karhunen - Loeve Transformation in Radar Signal Features Processing  

Microsoft Academic Search

One of the most difficult tasks in the radar signal processing is an optimal features extraction and classification. The multifunction radar systems can not be classified and precisely recognized by most of new and modern Electronic Support Measure and Electronic Intelligence devices in the real time. It is directly combined with a possibility of measurement radar features. The number of

A. Kawalec; R. Owczarek; J. Dudczyk

2006-01-01

230

The bootstrap and its application in signal processing  

Microsoft Academic Search

The bootstrap is an attractive tool for assessing the accuracy of estimators and testing hypothesis for parameters where conventional techniques are not valid, such as in small data-sample situations. We highlight the motivations for using the bootstrap in typical signal processing applications and give several practical examples. Bootstrap methods for testing statistical hypotheses are described and we provide an analysis

A. M. Zoubir; B. Boashash

1998-01-01

231

Deep Learning and Its Applications to Signal and Information Processing  

Microsoft Academic Search

INTRODUCTION TO DEEP LEARNING Many traditional machine learning and signal processing techniques exploit shallow architectures, which contain a single layer of nonlinear feature transformation. Examples of shallow architectures are conventional hidden Markov models (HMMs), linear or nonlinear dynamical systems, conditional random fields (CRFs), maximum entropy (MaxEnt) models, support vector machines (SVMs), kernel regression, and multilayer perceptron (MLP) with a single

Dong Yu; Li Deng

2011-01-01

232

Signal processing tools for geoacoustic inversion in shallow water  

E-print Network

Signal 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 at low frequency (0- 150Hz) in shallow water (0-400m) with a single receiver. Although it is a classical

Boyer, Edmond

233

NONLINEAR SIGNAL PROCESSING BASED ON REPRODUCING KERNEL HILBERT SPACE  

E-print Network

of this work. Without his guidance, imagination, and enthusiasm, passion, which I admire, this dissertation and constructive advice. I am also grateful to Dr. Andrzej Cichocki from the Laboratory for Advanced Brain Signal Processing in RIKEN Brain Science Institute in Japan for his guidance and words of wisdom during my summer

Slatton, Clint

234

Guidelines for affective signal processing (ASP): From lab to life  

Microsoft Academic Search

This article presents the rationale behind ACII2009's special session: Guidelines for Affective Signal Processing (ASP): From lab to life. Although affect is embraced by both science and engineering, its recognition has not reached a satisfying level. Through a concise overview of ASP and the automatic classification of affect, we provide understanding for the problems encountered. Next, we identify guidelines for

Egon L. van den Broek; Joris H. Janssen; Joyce H. D. M. Westerink; J. Cohn; A. Nijholt; M. Pantic

2009-01-01

235

Multiscale Statistical Models for Signal and Image Processing.  

National Technical Information Service (NTIS)

We are developing a general theory for multi scale signal and image modeling, processing, and analysis that matched to singularity-rich data, such as transients and images with edges. Using a linguistic analogy, our model can be interpreted as grammars th...

R. G. Baraniuk

2004-01-01

236

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

237

Automatic Derivation and Implementation of Signal Processing Algorithms  

Microsoft Academic Search

We present a computer algebra framework to automatically derive and implement algorithms for digital signal processing. The two main parts of the framework are AREP, a library for symbolic manipulation of group representations and structured matrices, and SPL, a compiler turning matrix expressions into efficient imperative-style numerical programs.

Sebastian Egner; Jeremy Johnson; David Padua; Jianxin Xiong

2001-01-01

238

Applications of convex optimization in signal processing and digital communication  

Microsoft Academic Search

In the last two decades, the mathematical programming community has witnessed some spectacular advances in interior point methods and robust optimization. These advances have recently started to signifi- cantly impact various fields of applied sciences and engineering where computational efficiency is essential. This paper focuses on two such fields: digital signal processing and communication. In the past, the widely used

Zhi-Quan Luo

2003-01-01

239

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

240

[book REVIEW] IEEE SIGNAL PROCESSING MAGAZINE [128] JULY 2008  

E-print Network

of human visual perception. Nor is the book truly "about" digital imaging applications. Although from[book REVIEW] IEEE SIGNAL PROCESSING MAGAZINE [128] JULY 2008 Mathematics of Digital Images is a body of mathematics, equally as vast and diverse, from which techniques and algorithms are drawn

Fowler, James E.

241

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

242

A Signal Processing System for Underwater Acoustic ROV Communication  

Microsoft Academic Search

A high performance system for communication with untethered underwater vehicles is presented. The system is centered around multiple digital processors which perform a variety of signal processing tasks. The processors are combined into an array using a flexible architecture designed for communication prcessing. A basic system has been tested at 5 kbit\\/sec over the Rayleigh-fading multipath channel in Woods Hole

Lee E. Freitag; J. A. Catipovic

1989-01-01

243

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

244

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 serve as an analysis tool for studying factors affecting the gait under various conditions. Copyright, and fingerprint have been researched extensively for this purpose. Gait, the style of walking of an individual

Plataniotis, Konstantinos N.

245

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing  

E-print Network

Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010, Article ID 729378, 12 pages doi:10.1155/2010/729378 Research Article K-Means Based Fingerprint in an automatic fingerprint recognition system is the segmentation of fingerprint images. Existing methods

Zhang, Richard "Hao"

246

Video camera signal processing IC with CCD delay lines  

Microsoft Academic Search

A video camera signal-processing IC that includes CCD (charge coupled device) delay lines (DLs) and lowpass filters has been developed using a Bi-CMOS\\/CCD process. The IC greatly contributes to reduced size and improved reliability in video movie circuits. The IC incorporates four 1H CCD-DLs and five lowpass filters, thereby making the circuit board space more compact. Automatic adjustment of CCD-DL

T. Kiyofuji; M. Yoshida; M. Aso; N. Murakami; S. Miyazaki

1990-01-01

247

IEEE SIGNAL PROCESSING LETTERS, VOL. 17, NO. 11, NOVEMBER 2010 913 Sparse Representation of Musical Signals  

E-print Network

Abstract--The sparse representation of music sounds that con- sist of a single note at a time was examinedIEEE SIGNAL PROCESSING LETTERS, VOL. 17, NO. 11, NOVEMBER 2010 913 Sparse Representation of Musical in [1]. Here, we extend the results to a more generic setting where music sounds may con- tain multiple

Kuo, C.-C. "Jay"

248

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

249

A robust sinusoidal signal processing method for interferometers  

NASA Astrophysics Data System (ADS)

Laser interferometers are widely used as a reference for length measurement. Reliable bidirectional optical fringe counting is normally obtained by using two orthogonally sinusoidal signals derived from the two outputs of an interferometer with path difference. These signals are subject to be disturbed by the geometrical errors of the moving target that causes the separation and shift of two interfering light spots on the detector. It results in typical Heydemann errors, including DC drift, amplitude variation and out-of-orthogonality of two sinusoidal signals that will seriously reduce the accuracy of fringe counting. This paper presents a robust sinusoidal signal processing method to correct the distorted waveforms by hardware. A corresponding circuit board has been designed. A linear stage equipped with a laser displacement interferometer and a height gauge equipped with a linear grating interferometer are used as the test beds. Experimental results show that, even with a seriously disturbed input waveform, the output Lissajous circle can always be stabilized after signal correction. This robust method increases the stability and reliability of the sinusoidal signals for data acquisition device to deal with pulse count and phase subdivision.

Wu, Xiang-long; Zhang, Hui; Tseng, Yang-Yu; Fan, Kuang-Chao

2013-10-01

250

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

251

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

252

Processing speed in recurrent visual networks correlates with general intelligence.  

PubMed

Studies on the neural basis of general fluid intelligence strongly suggest that a smarter brain processes information faster. Different brain areas, however, are interconnected by both feedforward and feedback projections. Whether both types of connections or only one of the two types are faster in smarter brains remains unclear. Here we show, by measuring visual evoked potentials during a texture discrimination task, that general fluid intelligence shows a strong correlation with processing speed in recurrent visual networks, while there is no correlation with speed of feedforward connections. The hypothesis that a smarter brain runs faster may need to be refined: a smarter brain's feedback connections run faster. PMID:17259858

Jolij, Jacob; Huisman, Danielle; Scholte, Steven; Hamel, Ronald; Kemner, Chantal; Lamme, Victor A F

2007-01-01

253

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

254

Modern Techniques in Acoustical Signal and Image Processing  

SciTech Connect

Acoustical signal processing problems can lead to some complex and intricate techniques to extract the desired information from noisy, sometimes inadequate, measurements. The challenge is to formulate a meaningful strategy that is aimed at performing the processing required even in the face of uncertainties. This strategy can be as simple as a transformation of the measured data to another domain for analysis or as complex as embedding a full-scale propagation model into the processor. The aims of both approaches are the same--to extract the desired information and reject the extraneous, that is, develop a signal processing scheme to achieve this goal. In this paper, we briefly discuss this underlying philosophy from a ''bottom-up'' approach enabling the problem to dictate the solution rather than visa-versa.

Candy, J V

2002-04-04

255

Mass spectral peak distortion due to fourier transform signal processing.  

PubMed

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. PMID:25261219

Rockwood, Alan L; Erve, John C L

2014-12-01

256

Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation.  

PubMed

Pulse oximeters are monitors that noninvasively measure heart rate and blood oxygen saturation (SpO2). Unfortunately, pulse oximetry is prone to artifacts which negatively impact the accuracy of the measurement and can cause a significant number of false alarms. We have developed an algorithm to segment pulse oximetry signals into pulses and estimate the signal quality in real time. The algorithm iteratively calculates a signal quality index (SQI) ranging from 0 to 100. In the presence of artifacts and irregular signal morphology, the algorithm outputs a low SQI number. The pulse segmentation algorithm uses the derivative of the signal to find pulse slopes and an adaptive set of repeated Gaussian filters to select the correct slopes. Cross-correlation of consecutive pulse segments is used to estimate signal quality. Experimental results using two different benchmark data sets showed a good pulse detection rate with a sensitivity of 96.21% and a positive predictive value of 99.22%, which was equivalent to the available reference algorithm. The novel SQI algorithm was effective and produced significantly lower SQI values in the presence of artifacts compared to SQI values during clean signals. The SQI algorithm may help to guide untrained pulse oximeter users and also help in the design of advanced algorithms for generating smart alarms. PMID:22986287

Karlen, W; Kobayashi, K; Ansermino, J M; Dumont, G A

2012-10-01

257

Signal processing environment for analysis and reduction (SPEAR)  

NASA Astrophysics Data System (ADS)

The need for a high-fidelity sensor design simulation model to accurately predict the system performance envelope and to offset the escalating cost of the system development and testing is widely accepted by the defense community. This paper presents one such example of the modeling capability developed for the ballistic missile defense (BMD) application, called the signal processing environment for analysis and reduction (SPEAR) simulation. SPEAR has become a key IR sensor design and signal processing performance verification tool for the BMD Advanced Sensor Technology Program (ASTP), the Discriminating Interceptor Technology Program (DITP), and the ground based interceptor (GBI) and, where it is used for sensitivity analyses, algorithm evaluations, and performance assessments. For these programs, SPEAR provides an algorithm testing simulation to evaluate candidate signal processing options, and implement and test performance of algorithms proposed through advanced technology programs. In addition, SPEAR is used to process real world data to provide assessments of sensor performance and provide preflight predictions. The simulation has been interfaced to the synthetic scene generation model (SSGM), a community standard background and target scene generation simulation. Through this interface sensor performance can be evaluated against realistically modeled backgrounds to evaluate filtering, detection, and false alarm performance. SPEAR is a hi-fidelity passive infrared (IR) sensor and signal processing simulation for staring scanning, and hybrid sensors. It allows the user to specify the IR sensor physics including the sensor, optics, focal plane array or scan chip assembly, analog signal processor, time dependent and object dependent processing parameters and specific noise sources such as optics, jitter, fixed pattern noise, dark current, and gamma spike noise. SPEAR is an Ada/PVWAVE combination. The sensor and signal processing is written in Ada and the execution, parameter input, and function analysis are controlled with the graphical user interface (GUI) written in PVWAVE. The signal processing techniques available as options include time dependent processing techniques such as adaptive threshold detection, background estimation and removal, morphological filtering, match filtering, target signature extraction, and object dependent processing techniques such as centroiding and pulse matching. SPEAR has simulation control options to allow the user to execute and examine data per frame (mission mode) or in a statistical mode to investigate parametric sensitivities of the sensor performance. Documentation of SPEAR includes manuals on the GUI, the SPEAR application components, and guidelines for adding new algorithms and features. This paper provides a summary of key algorithm and options in SPEAR. Examples of performance analysis results are provided. The paper includes stochastic analyses of both the above- the-horizon and below-the-horizon engagements of target and background generated scenes using SSGM. Also discussed are the evaluation of radiometric measurement precision, angular measurement precision, and detection of targets of varying intensities with respect to varying sensor signal processing techniques.

Smith, Brian C.; Kinashi, Yasuhiro

1997-10-01

258

On-Board Spaceborne Real-time Digital Signal Processing  

NASA Astrophysics Data System (ADS)

begin center Abstract end center This paper reports a preliminary study result of an on-board digital signal processing system It consists of the on-board processing requirement analysis functional specifications and implementation with the radiation tolerant field-programmable gate array FPGA technology The FPGA program is designed in the VHDL hardware description language and implemented onto a high density F PGA chip The design takes full advantage of the massively parallel architecture of the VirtexII FPGA logic slices to achieve real-time processing at a big data rate Further more an FFT algorithm s implementation with the system is provided as an illustration

Gao, G.; Long, F.; Liu, L.

259

Analysis of Wide-Band Signals Using Wavelet Array Processing  

NASA Astrophysics Data System (ADS)

Wavelets transforms allow for precise time-frequency localization in the analysis of non-stationary signals. In wavelet analysis the trade-off between frequency bandwidth and time duration, also known as Heisenberg inequality, is by-passed using a fully scalable modulated window which solves the signal-cutting problem of Windowed Fourier Transform. We propose a new seismic array data processing procedure capable of displaying the localized spatial coherence of the signal in both the time- and frequency-domain, in turn deriving the propagation parameters of the most coherent signals crossing the array. The procedure consists in: a) Wavelet coherence analysis for each station pair of the instruments array, aimed at retrieving the frequency- and time-localisation of coherent signals. To this purpose, we use the normalised wavelet cross- power spectrum, smoothed along the time and scale domains. We calculate different coherence spectra adopting smoothing windows of increasing lengths; a final, robust estimate of the time-frequency localisation of spatially-coherent signals is eventually retrieved from the stack of the individual coherence distribution. This step allows for a quick and reliable signal discrimination: wave groups propagating across the network will manifest as high-coherence patches spanning the corresponding time-scale region. b) Once the signals have been localised in the time and frequency domain,their propagation parameters are estimated using a modified MUSIC (MUltiple SIgnal Characterization) algorithm. We select the MUSIC approach as it demonstrated superior performances in the case of low SNR signals, more plane waves contemporaneously impinging at the array and closely separated sources. The narrow-band Coherent Signal Subspace technique is applied to the complex Continuous Wavelet Transform of multichannel data for improving the singularity of the estimated cross-covariance matrix and the accuracy of the estimated signal eigenvectors. Using synthetic multichannel data generated for different signal types, the resolution in time-frequency-slowness domains is estimated by a direct comparision with the Windowed Fourier Transform MUSIC algorithm. The main advantages of our Wavelet Transform MUSIC algorithm (WTM) consists in: a) The simplicity of the procedure, as different frequency bands are processed at once without sacrifying time resolution; b) Its ability to selectively process only those data windows which depict significant coherence throughout the network, thus ensuring the physical meaning of the solution. We applied this metodology to the study of the wavefield characteristic of seismo-volcanic activity recorded by a dense array of short-period seismometers deployed at Stromboli volcano during its 2002-2003 eruption. WTM gives precise descriptions of the distribution in time and frequency of the different wavefield components, in turn providing precise estimates of the corresponding wavevectors. These achievements represent a crucial step toward a better understanding of the seismic wavefields associated with volcanic activity.

Nisii, V.; Saccorotti, G.

2005-12-01

260

SOI based ultracompact polarization insensitive filter for PDM signal processing.  

PubMed

We propose and fabricate a scheme that combines a two-dimensional (2D) grating coupler and a delay interferometer (DI) in a loop configuration. According to the polarization states, the 2D grating coupler first splits the input signals into two paths, which copropagate in the loop and share a common DI, and then combines the two paths together to the same input port. The proposed device is polarization insensitive and can be used for polarization division multiplexed (PDM) signal processing. For demonstration, the PDM non return-to-zero differential-phase-shift-keying signals can be demodulated successfully. The bit error ratio measurements show an error free operation, reflecting the good performance and the practicability of the proposed device. PMID:23939054

Xiang, Lei; Yu, Yu; Qin, Yaguang; Zou, Jinghui; Zou, Bingrong; Zhang, Xinliang

2013-07-15

261

Neural predictive error signal correlates with depressive illness severity in a game paradigm.  

PubMed

Considerable experimental evidence supports the existence of predictive error signals in various brain regions during associative learning in animals and humans. These regions include the prefrontal cortex, temporal lobe, cerebellum and monoamine systems. Various quantitative theories have been developed to describe behaviour during learning, including Rescorla-Wagner, Temporal Difference and Kalman filter models. These theories may also account for neural error signals. Reviews of imaging studies of depressive illness have consistently implicated the prefrontal and temporal lobes as having abnormal function, and sometimes structure, whilst the monoamine systems are directly influenced by antidepressant medication. It was hypothesised that such abnormalities may be associated with a dysfunction of associative learning that would be reflected by different predictive error signals in depressed patients when compared with healthy controls. This was tested with 30 subjects, 15 with a major depressive illness, using a gambling paradigm and fMRI. Consistent with the hypothesis, depressed patients differed from controls in having an increased error signal. Additionally, for some brain regions, the magnitude of the error signal correlated with Hamilton depression rating of illness severity. Structural equation modelling was used to investigate hypothesised change in effective connectivity between prespecified regions of interest in the limbic and paralimbic system. Again, differences were found that in some cases correlated with illness severity. These results are discussed in the context of quantitative theories of brain function, clinical features of depressive illness and treatments. PMID:15325374

Steele, J D; Meyer, M; Ebmeier, K P

2004-09-01

262

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

263

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

264

Correlation  

Microsoft Academic Search

Discusses: (1) the need for a general factor to explain the correlation between tested psychophysical processes and (2) the importance of multiple correlation in solving the complex problems. Reports the contributions of Thurstone, Ruml and Kelley to the methods of calculation of coefficients. Doll offers new ways of using corrections. Applications of this method in new fields other than applied

James Burt Miner

1917-01-01

265

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

266

The genetic correlation between intelligence and speed of information processing  

Microsoft Academic Search

This study examined the contributions of genetic and environmental factors to the observed correlation between intelligence test scores and speed of information processing, based on data for same-sex adult twin pairs (age, 15–57). Verbal and performance IQ scores from the Multidimensional Abilities Battery, as well as 11 reaction-time measures derived from a battery of information-processing tasks, were available for 50

Laura A. Baker; Phillip A. Vernon; Hsiu-Zu Ho

1991-01-01

267

Neural Correlates of Semantic Competition during Processing of Ambiguous Words  

Microsoft Academic Search

The current study investigated the neural correlates that underlie the processing of ambiguous words and the potential effects of semantic competition on that processing. Participants performed speeded lexical decisions on semantically related and unrelated prime–target pairs presented in the auditory modality. The primes were either ambiguous words (e.g., ball) or unambiguous words (e.g., athlete), and targets were either semantically related

Natalia Y. Bilenko; Christopher M. Grindrod; Emily B. Myers; Sheila E. Blumstein

2008-01-01

268

Biological signal processing with a genetic toggle switch.  

PubMed

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

269

Missile signal processing common computer architecture for rapid technology upgrade  

NASA Astrophysics Data System (ADS)

Interceptor missiles process IR images to locate an intended target and guide the interceptor towards it. Signal processing requirements have increased as the sensor bandwidth increases and interceptors operate against more sophisticated targets. A typical interceptor signal processing chain is comprised of two parts. Front-end video processing operates on all pixels of the image and performs such operations as non-uniformity correction (NUC), image stabilization, frame integration and detection. Back-end target processing, which tracks and classifies targets detected in the image, performs such algorithms as Kalman tracking, spectral feature extraction and target discrimination. In the past, video processing was implemented using ASIC components or FPGAs because computation requirements exceeded the throughput of general-purpose processors. Target processing was performed using hybrid architectures that included ASICs, DSPs and general-purpose processors. The resulting systems tended to be function-specific, and required custom software development. They were developed using non-integrated toolsets and test equipment was developed along with the processor platform. The lifespan of a system utilizing the signal processing platform often spans decades, while the specialized nature of processor hardware and software makes it difficult and costly to upgrade. As a result, the signal processing systems often run on outdated technology, algorithms are difficult to update, and system effectiveness is impaired by the inability to rapidly respond to new threats. A new design approach is made possible three developments; Moore's Law - driven improvement in computational throughput; a newly introduced vector computing capability in general purpose processors; and a modern set of open interface software standards. Today's multiprocessor commercial-off-the-shelf (COTS) platforms have sufficient throughput to support interceptor signal processing requirements. This application may be programmed under existing real-time operating systems using parallel processing software libraries, resulting in highly portable code that can be rapidly migrated to new platforms as processor technology evolves. Use of standardized development tools and 3rd party software upgrades are enabled as well as rapid upgrade of processing components as improved algorithms are developed. The resulting weapon system will have a superior processing capability over a custom approach at the time of deployment as a result of a shorter development cycles and use of newer technology. The signal processing computer may be upgraded over the lifecycle of the weapon system, and can migrate between weapon system variants enabled by modification simplicity. This paper presents a reference design using the new approach that utilizes an Altivec PowerPC parallel COTS platform. It uses a VxWorks-based real-time operating system (RTOS), and application code developed using an efficient parallel vector library (PVL). A quantification of computing requirements and demonstration of interceptor algorithm operating on this real-time platform are provided.

Rabinkin, Daniel V.; Rutledge, Edward; Monticciolo, Paul

2004-10-01

270

Neural Correlates of Sublexical Processing in Phonological Working Memory  

Microsoft Academic Search

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 responses to these manipulations under conditions of covert rehearsal (Experiment 1). A

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

2010-01-01

271

Neural Correlates of Bridging Inferences and Coherence Processing  

ERIC Educational Resources Information Center

We explored the neural correlates of bridging inferences and coherence processing during story comprehension using Positron Emission Tomography (PET). Ten healthy right-handed volunteers were visually presented three types of stories (Strong Coherence, Weak Coherence, and Control) consisted of three sentences. The causal connectedness among…

Kim, Sung-il; Yoon, Misun; Kim, Wonsik; Lee, Sunyoung; Kang, Eunjoo

2012-01-01

272

Neural Correlates of Sublexical Processing in Phonological Working Memory  

Microsoft Academic Search

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 responses to these manipulations under conditions of covert rehearsal (Experiment 1). A

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

2011-01-01

273

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

274

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

275

coherent demodulation of optical 8-phase shift-keying signals using homodyne detection and digital signal processing  

Microsoft Academic Search

We demonstrate coherent demodulation of optical 8-phase shift-keying signals for the first time. Since the carrier phase is estimated accurately through digital signal processing, the system performance is highly tolerant toward the carrier phase noise.

S. Tsukamotor; K. Katoh; K. Kikuchi

2006-01-01

276

Jitter measurement method for the PRML signal processing  

NASA Astrophysics Data System (ADS)

The Blu-ray Disc (BD), which achieves approximately five times the recording density as that of a DVD, employs 1-7PP encoding, a more efficient encoding method than EFM+ modulation (8-16) of DVD. The shortest mark length recorded by this method is 2T (approximately one-third of the length) as compared to 3T of a DVD (where T is the channel clock period). Because it is difficult to reproduce such high-density signal using binarized decoding, Partial Response Maximum Likelihood (PRML) is often used in its place. Jitter, which has been used as a reference in the evaluation of the reproducing signal of DVDs, does not necessarily match the bit error that results from PRML decoding. Consequently, BD which heavily uses PRML decoding requires a new evaluation method that replaces the conventional method using jitter evaluation. Because the correlation between the jitter and bit error is worse when the jitter of the 2T mark is predominant among all mark jitters, we focused our attention to jitters that exclude the jitter of the 2T mark as a reference for evaluating the S/N ratio of the system directly through the use of the inter-symbol interference analysis function of the time interval analyzer. This paper describes the analysis of the correlation between jitters that exclude the jitter of the 2T mark and the bit error rate.

Katano, Kazuya; Shoji, Mamoru; Kuono, Keiji; Watanabe, Katsuya

2005-09-01

277

Correlation between laser-induced breakdown spectroscopy signal and moisture content  

NASA Astrophysics Data System (ADS)

The possibility of using Laser-Induced Breakdown Spectroscopy (LIBS) for measuring the moisture content of fresh food samples is studied. The normalized line emission of oxygen is highly correlated with the moisture content of the sample, cheese in our case, and can be used as a moisture marker in situations where oxygen interference from the matrix is not a critical issue. The linear correlation between the oxygen signal and the moisture content in the sample shows great potential for using LIBS as an alternative spectroscopic method for moisture monitoring.

Liu, Yuan; Gigant, Lionel; Baudelet, Matthieu; Richardson, Martin

2012-07-01

278

Signal shredding by autogenic processes in sedimentary systems  

NASA Astrophysics Data System (ADS)

Erosional and depositional landscapes evolve in response to changes in external drivers such as climate, tectonic motion, and eustatic sea level. These changes are typically imposed via time-varying boundary conditions with a wide range of time scales, and are transmitted to the landscape via changes in sediment flux. The response of landscapes is then mediated by the mechanics of sediment transport. Understanding how signals of environmental forcing are transmitted and preserved in sedimentary systems is crucial for predicting landscape response to environmental change, and for the inverse problem of interpreting Earth history from landforms and the depositional record. It is generally understood that climatic or tectonic signals can be modified - for example, damped and/or phase-shifted - as they propagate through sedimentary systems. Here we examine a much stronger effect: sediment transport can act as a noisy, nonlinear filter that destroys (“shreds”) signals of environmental forcing so that they are not merely masked but entirely lost. Signal shredding is analogous to modulated turbulence in fluid flows. We demonstrate that autogenic variations in sediment transport associated with sediment storage and release act as a kind of “morphodynamic turbulence”, with a temporal spectrum and finite-size cutoff similar to fluid turbulence. External signals are destroyed when their time and magnitude scales fall within the range of autogenic fluctuations. Sufficiently high-amplitide and/or long-period signals survive, albeit with superimposed noise. We show using several landscape models that autogenic sediment storage and release, and hence signal shredding, result from the ubiquitous presence of thresholds in sediment transport systems - for example, avalanching, landsliding, bed load transport, and river avulsion. We confirm the signal-shredding effect experimentally by imposing cyclical variations in sediment supply on a table-top rice pile. We suggest that Earth's sedimentary archives could be dominated by transport “noise” on time scales up to tens of thousands of years. This time scale range overlaps in particular with known climatic time scales, meaning that in many systems the physical signature of these signals may be lost. On the other hand, depositional patterns associated with autogenic dynamics may be relatively uninfluenced by high-frequency external processes, and hence statistically predictable.

Jerolmack, D. J.; Paola, C.; Martin, R.

2009-12-01

279

Lab Exercises: Digital Signal Processing with Field Programmable Gate Arrays  

NSDL National Science Digital Library

This website features a collection of eight laboratory experiments in the use of Field Programmable Gate Arrays (FPGAs), user-configurable semiconductor devices, for digital signal processing (DSP). The labs cover both leading FPGA vendors (Xilinx and Altera), provide a MatLab/Simulink-based design flow and are intended for use in university-level classes in electrical and computer engineering. Site materials include downloadable files in two versions compatible with each vendor's devices, and student worksheets.

Meyer-Baese, Uwe

280

UniBoard: generic hardware for radio astronomy signal processing  

NASA Astrophysics Data System (ADS)

UniBoard is a generic high-performance computing platform for radio astronomy, developed as a Joint Research Activity in the RadioNet FP7 Programme. The hardware comprises eight Altera Stratix IV Field Programmable Gate Arrays (FPGAs) interconnected by a high speed transceiver mesh. Each FPGA is connected to two DDR3 memory modules and three external 10Gbps ports. In addition, a total of 128 low voltage differential input lines permit connection to external ADC cards. The DSP capability of the board exceeds 644E9 complex multiply-accumulate operations per second. The first production run of eight boards was distributed to partners in The Netherlands, France, Italy, UK, China and Korea in May 2011, with a further production runs completed in December 2011 and early 2012. The function of the board is determined by the firmware loaded into its FPGAs. Current applications include beamformers, correlators, digital receivers, RFI mitigation for pulsar astronomy, and pulsar gating and search machines The new UniBoard based correlator for the European VLBI network (EVN) uses an FX architecture with half the resources of the board devoted to station based processing: delay and phase correction and channelization, and half to the correlation function. A single UniBoard can process a 64MHz band from 32 stations, 2 polarizations, sampled at 8 bit. Adding more UniBoards can expand the total bandwidth of the correlator. The design is able to process both prerecorded and real time (eVLBI) data.

Hargreaves, J. E.

2012-09-01

281

Digital signal processing for high spectral efficiency optical networks  

NASA Astrophysics Data System (ADS)

Digital signal processing (DSP) for high spectrum efficiency transmission system are investigated in both long-haul and short haul optical networks. For long-haul transmission, two different super-Nyquist WDM systems based on advanced post (receiver side) and pre (transmitter side) DSP are demonstrated and studied. A novel DSP scheme for this optical super-Nyquist filtering 9-QAM like signals based on multi-modulus equalization (MMEQ) without post filter are proposed and experimentally demonstrated, which directly recovers the Nyquist filtered QPSK to a 9-QAM like signal. This improved filtering tolerance and transmission performance are demonstrated in an 8-channel 112-Gb/s wavelengthdivision- multiplexing (WDM) experiment with a 25GHz-grid over 2640-km single-mode fiber (SMF). Alternatively, a novel digital super-Nyquist signal generation scheme is proposed to further suppress the Nyquist signal bandwidth and reduce the channel crosstalk without using optical pre-filtering and using. Only optical couplers are needed for super- Nyquist WDM multiplexing. Using this scheme, we successfully generate and transmit 10 channel 32-GBaud (128-Gb/s) PDM-9-QAM signals within 25-GHz grid over 2975-km at a net SE of 4 bit/s/Hz (after excluding the 20% soft-decision FEC overhead). We extend the DSP for short haul optical transmission networks by using high order QAMs. We propose and experimentally demonstrate a high speed CAP-64QAM system using direct modulation laser (DML) based on direct detection and digital equalizations. Decision-directed least mean squares (DD-LMS) are used to equalize the CAP- 64QAM. Using this scheme, we successfully generate and transmit up to a record 60-Gb/s CAP-64QAM over 20-km stand single-mode fiber (SSMF) based on the DML and direct detection.

Zhang, Junwen; Yu, Jianjun; Chi, Nan

2013-12-01

282

Correlation time analysis of delay-Doppler waveforms generated from ocean-scattered GPS signals  

Microsoft Academic Search

The ocean-scattered Global Positioning System (GPS) signal can be used, in a bistatic radar configuration, for estimating the ocean surface roughness. This requires fitting a scattering model to the distribution of reflected power in delay and Doppler. The delay-Doppler map, or waveform, is generated through the cross-correlation of a local copy of the pseudorandom noise (PRN) code assigned to each

H. You; J. L. Garrison; G. Heckler; D. Smajlovic

2004-01-01

283

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

Microsoft Academic Search

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 biomechanical swallowing events were analyzed: hyoid elevation, pharyngeal constriction, and opening-closing of the pharyngoesophageal segment.

Michael A. Crary; Giselle D. Carnaby; Michael E. Groher

284

Neural cross-correlation and signal decorrelation: insights into coding of auditory space  

Microsoft Academic Search

The auditory systems of humans and many other species use the difference in the time of arrival of acoustic signals at the two ears to compute the lateral position of sound sources. This computation is assumed to initially occur in an assembly of neurons organized along a frequency-by-delay surface. Mathematically, the computations are equivalent to a two-dimensional cross-correlation of the

Kourosh Saberi; Agavni Petrosyan

2005-01-01

285

Correlation dynamics and enhanced signals for the identification of serial biomolecules and DNA bases  

NASA Astrophysics Data System (ADS)

Nanopore-based sequencing has demonstrated a significant potential for the development of fast, accurate, and cost-efficient fingerprinting techniques for next generation molecular detection and sequencing. We propose a specific multilayered graphene-based nanopore device architecture for the recognition of single biomolecules. Molecular detection and analysis can be accomplished through the detection of transverse currents as the molecule or DNA base translocates through the nanopore. To increase the overall signal-to-noise ratio and the accuracy, we implement a new ‘multi-point cross-correlation’ technique for identification of DNA bases or other molecules on the single molecular level. We demonstrate that the cross-correlations between each nanopore will greatly enhance the transverse current signal for each molecule. We implement first-principles transport calculations for DNA bases surveyed across a multilayered graphene nanopore system to illustrate the advantages of the proposed geometry. A time-series analysis of the cross-correlation functions illustrates the potential of this method for enhancing the signal-to-noise ratio. This work constitutes a significant step forward in facilitating fingerprinting of single biomolecules using solid state technology.

Ahmed, Towfiq; Haraldsen, Jason T.; Rehr, John J.; Di Ventra, Massimiliano; Schuller, Ivan; Balatsky, Alexander V.

2014-03-01

286

Knowledge-based signal processing for radar ESM systems  

NASA Astrophysics Data System (ADS)

Radar electronic support measures (ESM) systems perform the functions of threat detection and area surveillance to determine the identity and bearing of surrounding radar emitters. Automatic ESM systems incorporate a passive receiver to measure the parameters of detected radar pulses and an automatic processor to rapidly sort pulses and identify the emitters. Current processors use algorithmic processing methods which are inflexible and do not fully utilize available sources of a priori information. The paper discusses the role of knowledge-based processing methods and how they may be applied to the key ESM signal-processing functions of deinterleaving, merge and emitter identification. ESM processors are required to sort input pulse data streams exceeding one million pulses per second and minimize the reporting latency of new emitters. The paper further discusses the requirements to achieve real-time operation of knowledge-based ESM processing techniques.

Roe, J.; Cussons, S.; Feltham, A.

1990-10-01

287

Dynamic tracking down-conversion signal processing method based on reference signal for grating heterodyne interferometer  

NASA Astrophysics Data System (ADS)

Traditional displacement measurement systems by grating, which purely make use of fringe intensity to implement fringe count and subdivision, have rigid demands for signal quality and measurement condition, so they are not easy to realize measurement with nanometer precision. Displacement measurement with the dual-wavelength and single-grating design takes advantage of the single grating diffraction theory and the heterodyne interference theory, solving quite well the contradiction between large range and high precision in grating displacement measurement. To obtain nanometer resolution and nanometer precision, high-power subdivision of interference fringes must be realized accurately. A dynamic tracking down-conversion signal processing method based on the reference signal is proposed. Accordingly, a digital phase measurement module to realize high-power subdivision on field programmable gate array (FPGA) was designed, as well as a dynamic tracking down-conversion module using phase-locked loop (PLL). Experiments validated that a carrier signal after down-conversion can constantly maintain close to 100 kHz, and the phase-measurement resolution and phase precision are more than 0.05 and 0.2 deg, respectively. The displacement resolution and the displacement precision, corresponding to the phase results, are 0.139 and 0.556 nm, respectively.

Wang, Guochao; Yan, Shuhua; Zhou, Weihong; Gu, Chenhui

2012-08-01

288

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

289

Removal of correlated noise by modeling the signal of interest in the wavelet domain.  

PubMed

Images, captured with digital imaging devices, often contain noise. In literature, many algorithms exist for the removal of white uncorrelated noise, but they usually fail when applied to images with correlated noise. In this paper, we design a new denoising method for the removal of correlated noise, by modeling the significance of the noise-free wavelet coefficients in a local window using a new significance measure that defines the "signal of interest" and that is applicable to correlated noise. We combine the intrascale model with a hidden Markov tree model to capture the interscale dependencies between the wavelet coefficients. We propose a denoising method based on the combined model and a less redundant wavelet transform. We present results that show that the new method performs as well as the state-of-the-art wavelet-based methods, while having a lower computational complexity. PMID:19398408

Goossens, Bart; Pizurica, Aleksandra; Philips, Wilfried

2009-06-01

290

Experimental study of the relationship between in-process signals and cut quality in gas-assisted laser cutting  

NASA Astrophysics Data System (ADS)

The patented "Acoustic Mirro?' has previously been used to investigate weld quality in laser welding. A good correlation was observed between the acoustic signal and weld quality. This success led the authors to investigate the use of the acoustic mirror in gas assisted laser cutting. A piezoelectric transducer mounted on the rear of the final mirror of the beam path was used to observe high frequency vibration due to reflected energy from the cutting process. Off-line inspection of the cut samples enabled the determination of cut quality. A correlation was obtained between the RMS value of the acoustic signal and full penetration of the laser beam, a decrease in signal corresponding to penetrating. Dross adhesion was also indicated by an increase in the level. Changes in the low frequency modulation showed some correlation to cut quality. Guidelines for the use of the acoustic signal as an indicator of fault cutting are discussed.

Zheng, H. Y.; Brookfield, D. J.; Steen, William M.

1990-10-01

291

Linear correlation between fractal dimension of EEG signal and handgrip force.  

PubMed

Fractal dimension (FD) has been proved useful in quantifying the complexity of dynamical signals in biology and medicine. In this study, we measured FDs of human electroencephalographic (EEG) signals at different levels of handgrip forces. EEG signals were recorded from five major motor-related cortical areas in eight normal healthy subjects. FDs were calculated using three different methods. The three physiological periods of handgrip (command preparation, movement and holding periods) were analyzed and compared. The results showed that FDs of the EEG signals during the movement and holding periods increased linearly with handgrip force, whereas FD during the preparation period had no correlation with force. The results also demonstrated that one method (Katz's) gave greater changes in FD, and thus, had more power in capturing the dynamic changes in the signal. The linear increase of FD, together with results from other EEG and neuroimaging studies, suggest that under normal conditions the brain recruits motor neurons at a linear progress when increasing the force. PMID:16028075

Liu, J Z; Yang, Q; Yao, B; Brown, R W; Yue, G H

2005-08-01

292

Sewer system flow components identification using signal processing.  

PubMed

The development of a continuous model to simulate the behaviour of sewer systems requires detailed information on each component of the flows contributing to the global discharge. In this paper authors investigate a novel method based on signal processing and long time series data implemented with a 2 min time step (flow rate, conductivity, pH and turbidity) in order to identify the dry weather components in a separated stormwater sewer system draining an industrial catchment. The wavelet analysis is applied to the recorded data to identify main components in dry weather flow after the removing of the signal noise. This paper highlights also a method to detect inflow into sewer system and shows how hydrological modelling can be used to characterise the relevant components. These techniques could be used as a basis for several applications. PMID:20595760

Dorval, F A; Chocat, B; Emmanuel, E; Lipeme Kouyi, G

2010-01-01

293

Developments in Acoustic Direction Sensing, Signal Processing and PVDF Film.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. This thesis details work in the continuing development of an acoustic direction sensor. The basic theoretical principles behind the acoustic excitation of flexural vibration modes in circularly symmetric bodies are explained, and the effects of these principles on the design of a practical sensor are studied. It is explained how signal processing improvements have allowed accurate directional information to be extracted from such a sensor. Software modifications are explained which use direct calibration of a sensor to give improved directional accuracy, combined with reductions in processing time. An improvement to the analogue bandpass filtering of the incoming signals is explained. The use of the new facilities provided in observing the second flexural mode of the sensor, and hence in reducing the inherent rotational ambiguity in the directionality of the device, is explained. The applicability of digital signal processing techniques to the improvement of the sensitivity of the device is examined and the processing method developed is explained. A use of the phase information obtained by this technique in further reducing ambiguity is proposed, and shown to be practical. The use of piezo-electric polyvinylidene difluoride film in the determination of the orientation of the fundamental flexural mode, is proposed. Feasibility studies are carried out to show the validity of the technique, and to examine the properties of the proposed device. Further suggestions are made about the design of a practical device. Finally, the current practical developments of the acoustic direction sensor are discussed, and future developments proposed.

Bull, Martyn D.

294

Position Estimation Method on Salient-Pole Permanent-Magnet Synchronous Motor Using High-Frequency Current Correlated Signals  

NASA Astrophysics Data System (ADS)

This paper proposes a new method for position estimation of salient-pole permanent-magnet synchronous motor using the second high-frequency current correlated signal in new coordinates in addition to the conventional high-frequency current correlated signal. In the proposed method, even when a spatially-rotating ellipse-shape high-frequency voltage is injected, the relation between the position error and the estimated position shows a linear correlation in the region of ±?/2.

Tomigashi, Yoshio; Takao, Hiroshi; Ueyama, Kenji

295

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

296

Neural Correlates of Semantic Competition during Processing of Ambiguous Words  

Microsoft Academic Search

Abstract & The current,study investigated the neural,correlates that underlie,the processing,of ambiguous,words,and,the poten- tial effects of semantic,competition,on that processing. Parti- cipants performed,speeded,lexical decisions,on semantically related and,unrelated,prime–target,pairs presented,in the auditory modality. The primes,were,either ambiguous,words (e.g., ball) or unambiguous words (e.g., athlete), and targets were either semantically related to the dominant (i.e., most frequent) meaning of the ambiguous prime word (e.g., soccer) or

Natalia Y. Bilenko; Christopher M. Grindrod; Emily B. Myers; Sheila E. Blumstein

2009-01-01

297

Correlation-autofocusing-spectral 2-D ISAR image reconstruction from linear frequency modulated signals  

Microsoft Academic Search

In this paper, by applying an analytic geometric approach, a model of an ISAR (inverse synthetic aperture radar) signal with linear frequency modulation is developed. An ISAR scenario of the rectilinear movement of a 2D target in the 3D coordinate system is described. An image reconstruction procedure, independent of the trajectory parameters of the target is suggested. The image processing

A. D. Lazarov; C. N. Minchev

2002-01-01

298

Cross-correlation Performance Comparison of L1 & L2C GPS Codes for Weak Signal Acquisition  

Microsoft Academic Search

The GPS constellation now contains six fully-operational Block IIR-M satellites. Each of these modernized satellites transmits the second GPS civil signal L2C. One of the key objectives of the L2C signal is to offer high cross-correlation protection, allowing weak signal acquisition in the presence of strong GPS signals in environments such as inside buildings and in urban canyons. The L2C

Sana Ullah Qaisar; Andrew G. Dempster

299

Structural characterization of a ribonuclease III processing signal.  

PubMed Central

The structure of a ribonuclease III processing signal from bacteriophage T7 was examined by NMR spectroscopy, optical melting, and chemical and enzymatic modification. A 41 nucleotide variant of the T7 R1.1 processing signal has two Watson-Crick base-paired helices separated by an internal loop, consistent with its predicted secondary structure. The internal loop is neither rigidly structured nor completely exposed to solvent, and seems to be helical. The secondary structure of R1.1 RNA is largely insensitive to the monovalent cation concentration, which suggests that the monovalent cation sensitivity of secondary site cleavage by RNase III is not due to a low salt-induced RNA conformational change. However, spectroscopic data show that Mg2+ affects the conformation of the internal loop, suggesting a divalent cation binding site(s) within this region. The Mg(2+)-dependence of RNase III processing of some substrates may reflect not only a requirement for a divalent cation as a catalytic cofactor, but also a requirement for a local RNA conformation which is divalent cation-stabilized. Images PMID:8127710

Schweisguth, D C; Chelladurai, B S; Nicholson, A W; Moore, P B

1994-01-01

300

Living ordered neural networks as model systems for signal processing  

NASA Astrophysics Data System (ADS)

Neural circuit architecture is a fundamental characteristic of the brain, and how architecture is bound to biological functions is still an open question. Some neuronal geometries seen in the retina or the cochlea are intriguing: information is processed in parallel by several entities like in "pooling" networks which have recently drawn the attention of signal processing scientists. These systems indeed exhibit the noise-enhanced processing effect, which is also actively discussed in the neuroscience community at the neuron scale. The aim of our project is to use in-vitro ordered neuron networks as living paradigms to test ideas coming from the computational science. The different technological bolts that have to be solved are enumerated and the first results are presented. A neuron is a polarised cell, with an excitatory axon and a receiving dendritic tree. We present how soma confinement and axon differentiation can be induced by surface functionalization techniques. The recording of large neuron networks, ordered or not, is also detailed and biological signals shown. The main difficulty to access neural noise in the case of weakly connected networks grown on micro electrode arrays is explained. This open the door to a new detection technology suitable for sub-cellular analysis and stimulation, whose development will constitute the next step of this project.

Villard, C.; Amblard, P. O.; Becq, G.; Gory-Fauré, S.; Brocard, J.; Roth, S.

2007-06-01

301

A Random Walk into Optical Signal Processing and Integrated Optofluidics  

NASA Astrophysics Data System (ADS)

As a young child, I knew that I wanted to be a paleontologist. My parents, both artists, did their best to encourage me in my quest to dig for dinosaurs. However, decisions during my late high school and early college years serendipitously shifted my path so that I ended up pursuing a career in applied physics. In particular, my career path has been centered in optics with an emphasis on holography and signal processing. This talk will discuss my research in the areas of opto-electronic blind source separation and holographic photopolymers as well as the non-linear path that has gotten me to this point.

Baylor, Martha-Elizabeth

2013-04-01

302

Application of Bayesian recursive estimation for seismic signal processing  

NASA Astrophysics Data System (ADS)

Bayesian recursive estimation (BRE) requires that the posterior density function be estimated so that conditional mean estimates of desired parameters or states can be obtained. BRE has been referred to as a complete solution to the estimation problem since the posterior density function embodies all available statistical information (i.e., prior, likelihood and evidence). Until recent advances in BRE, most applications required that the system and measurement equations be linear, and that the process and measurement noise be Gaussian and white. A Kalman filter, KF, (closed form solution to the BRE) could be applied to systems that met these conditions. Previous applications of the KF to solve seismic signal processing problems (e.g., deconvolution) have had very limited success and acceptability in the geophysics signal processing community due to the restrictive nature of the KF. The recently new BRE development of sequential Monte Carlo (SMC) techniques for numerically solving non-stationary and non-linear problems has generated considerable interest and active research within the last decade. This thesis focuses upon the implementation of SMC techniques (e.g., particle filtering) for solving seismic signal processing problems. All the associated filters of BRE (hidden Markov model filter, KF, particle filter, Rao-Blackwellised particle filter, and jump Markov systems) and a new and highly robust and unique model of the seismic source wavelet are implemented in two innovative algorithms for solving the important problems of passive seismic event detection and blind seismic deconvolution. A ground-breaking concept in blind seismic deconvolution referred to as principle phase decomposition (PPD) is outlined and evaluated in this thesis. The PPD technique estimates and separates overlapping source wavelets instead of estimating high bandwidth reflection coefficients. It is shown that one can then easily generate reflection coefficients from the separated source wavelets. In this thesis many advantages of the PPD are outlined. Simulated seismogram data with low signal-to-noise ratios is blindly deconvolved where non-stationary, mixed-phase, and zero-phase source wavelets are present. I believe that there are currently no existing blind seismic deconvolution techniques which could obtain comparable performance results of the PPD technique. The work in this thesis has resulted in three IEEE publications and one peer reviewed conference publication.

Baziw, Erick

303

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."

1999-01-01

304

Real-time fractal signal processing in the time domain  

NASA Astrophysics Data System (ADS)

Fractal analysis has proven useful for the quantitative characterization of complex time series by scale-free statistical measures in various applications. The analysis has commonly been done offline with the signal being resident in memory in full length, and the processing carried out in several distinct passes. However, in many relevant applications, such as monitoring or forecasting, algorithms are needed to capture changes in the fractal measure real-time. Here we introduce real-time variants of the Detrended Fluctuation Analysis (DFA) and the closely related Signal Summation Conversion (SSC) methods, which are suitable to estimate the fractal exponent in one pass. Compared to offline algorithms, the precision is the same, the memory requirement is significantly lower, and the execution time depends on the same factors but with different rates. Our tests show that dynamic changes in the fractal parameter can be efficiently detected. We demonstrate the applicability of our real-time methods on signals of cerebral hemodynamics acquired during open-heart surgery.

Hartmann, András; Mukli, Péter; Nagy, Zoltán; Kocsis, László; Hermán, Péter; Eke, András

2013-01-01

305

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

306

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

307

Signals for Low Scale Gravity in the Process $??\\to ZZ$  

E-print Network

We investigate the sensitivity of future photon-photon colliders to low scale gravity scenarios via the process $\\gamma\\gamma \\to ZZ$ where the Kaluza-Klein boson exchange contributes only when the initial state photons have opposite helicity. We contrast this with the situation for the process $\\gamma \\gamma \\to \\gamma \\gamma$ where the $t$ and $u$ channel also contribute. We include the one-loop Standard Model background whose interference with the graviton exchange determines the experimental reach in measuring any deviation from the Standard Model expectations and explore how polarization can be exploited to enhance the signal over background. We find that a 1 TeV linear collider has an experimental reach to mass scale of about 4 TeV in this channel.

Micheal S. Berger; Brandon Zerbe

2005-07-25

308

Error reduction in laser remote sensing: combined effects of cross correlation and signal averaging.  

PubMed

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. PMID:18216912

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

1985-01-01

309

Identification and utilization of arbitrary correlations in models of recombination signal sequences  

PubMed Central

Background A significant challenge in bioinformatics is to develop methods for detecting and modeling patterns in variable DNA sequence sites, such as protein-binding sites in regulatory DNA. Current approaches sometimes perform poorly when positions in the site do not independently affect protein binding. We developed a statistical technique for modeling the correlation structure in variable DNA sequence sites. The method places no restrictions on the number of correlated positions or on their spatial relationship within the site. No prior empirical evidence for the correlation structure is necessary. Results We applied our method to the recombination signal sequences (RSS) that direct assembly of B-cell and T-cell antigen-receptor genes via V(D)J recombination. The technique is based on model selection by cross-validation and produces models that allow computation of an information score for any signal-length sequence. We also modeled RSS using order zero and order one Markov chains. The scores from all models are highly correlated with measured recombination efficiencies, but the models arising from our technique are better than the Markov models at discriminating RSS from non-RSS. Conclusions Our model-development procedure produces models that estimate well the recombinogenic potential of RSS and are better at RSS recognition than the order zero and order one Markov models. Our models are, therefore, valuable for studying the regulation of both physiologic and aberrant V(D)J recombination. The approach could be equally powerful for the study of promoter and enhancer elements, splice sites, and other DNA regulatory sites that are highly variable at the level of individual nucleotide positions. PMID:12537561

Cowell, Lindsay G; Davila, Marco; Kepler, Thomas B; Kelsoe, Garnett

2002-01-01

310

Neural pulse frequency modulation of an exponentially correlated Gaussian process  

NASA Technical Reports Server (NTRS)

The effect of NPFM (Neural Pulse Frequency Modulation) on a stationary Gaussian input, namely an exponentially correlated Gaussian input, is investigated with special emphasis on the determination of the average number of pulses in unit time, known also as the average frequency of pulse occurrence. For some classes of stationary input processes where the formulation of the appropriate multidimensional Markov diffusion model of the input-plus-NPFM system is possible, the average impulse frequency may be obtained by a generalization of the approach adopted. The results are approximate and numerical, but are in close agreement with Monte Carlo computer simulation results.

Hutchinson, C. E.; Chon, Y.-T.

1976-01-01

311

Detection and Processing Techniques of FECG Signal for Fetal Monitoring  

Microsoft Academic Search

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

M. A. Hasan; M. B. I. Reaz; M. I. Ibrahimy; M. S. Hussain; J. Uddin

2009-01-01

312

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

313

Digital speckle correlation method based on wavelet-packet noise-reduction processing.  

PubMed

Despite the advantages of being highly sensitive and nondestructive, the digital speckle correlation method (DSCM) may have difficulties in detecting tiny defects such as delaminations in multilayer ceramic capacitors. This is because the presence of background noise always complicates the data processing. We present a new algorithm, which employs the wavelet-packet noise-reduction process together with the improved DSCM, to improve data processing. Both the computational error and the noise are shown to be reduced successfully by this new algorithm. The accuracy (or precision) of the improved DSCM is increased after operation of the wavelet-packet noise-reduction process. The most important feature of this new algorithm is that it can extract a small hillock signal from a large noisy background in a DSCM deformation result. This helps to save time in the detection of tiny defects, such as delamination, in a miniaturized electronic component. PMID:18319947

Dai, X; Chan, Y C; So, A C

1999-06-01

314

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

315

Developmental Changes of BOLD Signal Correlations with Global Human EEG Power and Synchronization during Working Memory  

Microsoft Academic Search

In humans, theta band (5–7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the level of theta and

Lars Michels; Rafael Lüchinger; Thomas Koenig; Ernst Martin; Daniel Brandeis

2012-01-01

316

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

317

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

318

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optical signal-processing systems based on anisotropic media  

NASA Astrophysics Data System (ADS)

Partially coherent optical systems for signal processing are considered. The transfer functions are formed in these systems by interference of polarised light transmitted by an anisotropic medium. It is shown that such systems can perform various integral transformations of both optical and electric signals, in particular, two-dimensional Fourier and Fresnel transformations, as well as spectral analysis of weak light sources. It is demonstrated that such systems have the highest luminosity and vibration immunity among the systems with interference formation of transfer functions. An experimental investigation is reported of the application of these systems in the processing of signals from a linear hydroacoustic antenna array, and in measurements of the optical spectrum and of the intrinsic noise.

Kiyashko, B. V.

1995-10-01

319

Correlation between light scattering signal and tissue reversibility in rat brain exposed to hypoxia  

NASA Astrophysics Data System (ADS)

Light scattering signal is a potential indicator of tissue viability in brain because cellular and subcellular structural integrity should be associated with cell viability in brain tissue. We previously performed multiwavelength diffuse reflectance measurement for a rat global ischemic brain model and observed a unique triphasic change in light scattering at a certain time after oxygen and glucose deprivation. This triphasic scattering change (TSC) was shown to precede cerebral ATP exhaustion, suggesting that loss of brain tissue viability can be predicted by detecting scattering signal. In the present study, we examined correlation between light scattering signal and tissue reversibility in rat brain in vivo. We performed transcranial diffuse reflectance measurement for rat brain; under spontaneous respiration, hypoxia was induced for the rat by nitrogen gas inhalation and reoxygenation was started at various time points. We observed a TSC, which started at 140 +/- 15 s after starting nitrogen gas inhalation (mean +/- SD, n=8). When reoxygenation was started before the TSC, all rats survived (n=7), while no rats survived when reoxygenation was started after the TSC (n=8). When reoxygenation was started during the TSC, rats survived probabilistically (n=31). Disability of motor function was not observed for the survived rats. These results indicate that TSC can be used as an indicator of loss of tissue reversibility in brains, providing useful information on the critical time zone for treatment to rescue the brain.

Kawauchi, Satoko; Sato, Shunichi; Uozumi, Yoichi; Nawashiro, Hiroshi; Ishihara, Miya; Kikuchi, Makoto

2010-02-01

320

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

321

Order tracking signal processing for open rotor acoustics  

NASA Astrophysics Data System (ADS)

Counter-rotating open rotor acoustic measurements were processed using a two-shaft Vold-Kalman order tracking filter, providing new insight into the complicated noise generation mechanisms of this type of system. The multi-shaft formulation of the Vold-Kalman filter can determine a time-accurate output of shaft order tones associated with each rotor, even as the rotation rate of the two rotors varies. This is a major improvement over the usual short time Fourier transform method for many applications. It was found that the contribution from each rotor to the individual tones varies strongly as a function of shaft order and operating condition. The order tracking filter is also demonstrated as a robust tool for separating the tonal and broadband components of a signal for which the usual shaft phase averaging methods fail.

Stephens, David B.; Vold, Håvard

2014-08-01

322

On adaptive robustness approach to Anti-Jam signal processing  

NASA Astrophysics Data System (ADS)

An effective approach to exploiting statistical differences between desired and jamming signals named adaptive robustness is proposed and analyzed in this paper. It combines conventional Bayesian, adaptive, and robust approaches that are complementary to each other. This combining strengthens the advantages and mitigates the drawbacks of the conventional approaches. Adaptive robustness is equally applicable to both jammers and their victim systems. The capabilities required for realization of adaptive robustness in jammers and victim systems are determined. The employment of a specific nonlinear robust algorithm for anti-jam (AJ) processing is described and analyzed. Its effectiveness in practical situations has been proven analytically and confirmed by simulation. Since adaptive robustness can be used by both sides in electronic warfare, it is more advantageous for the fastest and most intelligent side. Many results obtained and discussed in this paper are also applicable to commercial applications such as communications in unregulated or poorly regulated frequency ranges and systems with cognitive capabilities.

Poberezhskiy, Y. S.; Poberezhskiy, G. Y.

323

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

324

Sparse multiple kernel learning for signal processing applications.  

PubMed

In many signal processing applications, grouping of features during model development and the selection of a small number of relevant groups can be useful to improve the interpretability of the learned parameters. While a lot of work based on linear models has been reported to solve this problem, in the last few years, multiple kernel learning has come up as a candidate to solve this problem in nonlinear models. Since all of the multiple kernel learning algorithms to date use convex primal problem formulations, the kernel weights selected by these algorithms are not strictly the sparsest possible solution. The main reason for using a convex primal formulation is that efficient implementations of kernel-based methods invariably rely on solving the dual problem. This work proposes the use of an additional log-based concave penalty term in the primal problem to induce sparsity in terms of groups of parameters. A generalized iterative learning algorithm, which can be used with a linear combination of this concave penalty term with other penalty terms, is given for model parameter estimation in the primal space. It is then shown that a natural extension of the method to nonlinear models using the "kernel trick" results in a new algorithm, called Sparse Multiple Kernel Learning (SMKL), which generalizes group-feature selection to kernel selection. SMKL is capable of exploiting existing efficient single kernel algorithms while providing a sparser solution in terms of the number of kernels used as compared to the existing multiple kernel learning framework. A number of signal processing examples based on the use of mass spectra for cancer detection, hyperspectral imagery for land cover classification, and NIR spectra from wheat, fescue grass, and diesel are given to highlight the ability of SMKL to achieve a very high accuracy with a very few kernels. PMID:20299705

Subrahmanya, Niranjan; Shin, Yung C

2010-05-01

325

Optical correlation of ultra-wideband signals using time-space-conversion C. Seifarth, H. Knuppertz, J. Jahns  

E-print Network

Optical correlation of ultra-wideband signals using time-space-conversion C. Seifarth, H. Knuppertz acoustic waves and deflect it at different angles depending on the temporal spectral components of the input signal. Ultra-wideband (UWB) devices as defined by the European Commission spread their RF energy

Jahns, Jürgen

326

Spatiotemporal Correlations between Cytosolic and Mitochondrial Ca2+ Signals Using a Novel Red-Shifted Mitochondrial Targeted Cameleon  

PubMed Central

The transfer of Ca2+ from the cytosol into the lumen of mitochondria is a crucial process that impacts cell signaling in multiple ways. Cytosolic Ca2+ ([Ca2+]cyto) can be excellently quantified with the ratiometric Ca2+ probe fura-2, while genetically encoded Förster resonance energy transfer (FRET)-based fluorescent Ca2+ sensors, the cameleons, are efficiently used to specifically measure Ca2+ within organelles. However, because of a significant overlap of the fura-2 emission with the spectra of the cyan and yellow fluorescent protein of most of the existing cameleons, the measurement of fura-2 and cameleons within one given cell is a complex task. In this study, we introduce a novel approach to simultaneously assess [Ca2+]cyto and mitochondrial Ca2+ ([Ca2+]mito) signals at the single cell level. In order to eliminate the spectral overlap we developed a novel red-shifted cameleon, D1GO-Cam, in which the green and orange fluorescent proteins were used as the FRET pair. This ratiometric Ca2+ probe could be successfully targeted to mitochondria and was suitable to be used simultaneously with fura-2 to correlate [Ca2+]cyto and [Ca2+]mito within same individual cells. Our data indicate that depending on the kinetics of [Ca2+]cyto rises there is a significant lag between onset of [Ca2+]cyto and [Ca2+]mito signals, pointing to a certain threshold of [Ca2+]cyto necessary to activate mitochondrial Ca2+ uptake. The temporal correlation between [Ca2+]mito and [Ca2+]cyto as well as the efficiency of the transfer of Ca2+ from the cytosol into mitochondria varies between different cell types. Moreover, slow mitochondrial Ca2+ extrusion and a desensitization of mitochondrial Ca2+ uptake cause a clear difference in patterns of mitochondrial and cytosolic Ca2+ oscillations of pancreatic beta-cells in response to D-glucose. PMID:23029314

Waldeck-Weiermair, Markus; Alam, Muhammad Rizwan; Khan, Muhammad Jadoon; Deak, Andras T.; Vishnu, Neelanjan; Karsten, Felix; Imamura, Hiromi; Graier, Wolfgang F.; Malli, Roland

2012-01-01

327

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

328

Correlative intravital imaging of cGMP signals and vasodilation in mice.  

PubMed

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 Ca(2+), 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

329

An Enhanced Signal Processing Strategy For Fetal Heart Rate Detection Charles Brewton  

E-print Network

ABSTRACT An Enhanced Signal Processing Strategy For Fetal Heart Rate Detection Charles Brewton Old the signal processing strategy for an acoustic fetal heart rate monitor. The theory, implementation, and testing of several possible signal processing strategies for fetal heart rate detection are presented

Zahorian, Stephen A.

330

Effect of extreme data loss on long-range correlated and anticorrelated signals quantified by detrended fluctuation analysis  

PubMed Central

Detrended fluctuation analysis (DFA) is an improved method of classical fluctuation analysis for nonstationary signals where embedded polynomial trends mask the intrinsic correlation properties of the fluctuations. To better identify the intrinsic correlation properties of real-world signals where a large amount of data is missing or removed due to artifacts, we investigate how extreme data loss affects the scaling behavior of long-range power-law correlated and anticorrelated signals. We introduce a segmentation approach to generate surrogate signals by randomly removing data segments from stationary signals with different types of long-range correlations. The surrogate signals we generate are characterized by four parameters: (i) the DFA scaling exponent ? of the original correlated signal u(i), (ii) the percentage p of the data removed from u(i), (iii) the average length ? of the removed (or remaining) data segments, and (iv) the functional form P(l) of the distribution of the length l of the removed (or remaining) data segments. We find that the global scaling exponent of positively correlated signals remains practically unchanged even for extreme data loss of up to 90%. In contrast, the global scaling of anticorrelated signals changes to uncorrelated behavior even when a very small fraction of the data is lost. These observations are confirmed on two examples of real-world signals: human gait and commodity price fluctuations. We further systematically study the local scaling behavior of surrogate signals with missing data to reveal subtle deviations across scales. We find that for anticorrelated signals even 10% of data loss leads to significant monotonic deviations in the local scaling at large scales from the original anticorrelated to uncorrelated behavior. In contrast, positively correlated signals show no observable changes in the local scaling for up to 65% of data loss, while for larger percentage of data loss, the local scaling shows overestimated regions (with higher local exponent) at small scales, followed by underestimated regions (with lower local exponent) at large scales. Finally, we investigate how the scaling is affected by the average length, probability distribution, and percentage of the remaining data segments in comparison to the removed segments. We find that the average length ?r of the remaining segments is the key parameter which determines the scales at which the local scaling exponent has a maximum deviation from its original value. Interestingly, the scales where the maximum deviation occurs follow a power-law relationship with ?r. Whereas the percentage of data loss determines the extent of the deviation. The results presented in this paper are useful to correctly interpret the scaling properties obtained from signals with extreme data loss. PMID:20365691

Ma, Qianli D. Y.; Bartsch, Ronny P.; Bernaola-Galvan, Pedro; Yoneyama, Mitsuru; Ivanov, Plamen Ch.

2012-01-01

331

Brain correlates of mathematical competence in processing mathematical representations.  

PubMed

The ability to extract numerical information from different representation formats (e.g., equations, tables, or diagrams) is a key component of mathematical competence but little is known about its neural correlate. Previous studies comparing mathematically less and more competent adults have focused on mental arithmetic and reported differences in left angular gyrus (AG) activity which were interpreted to reflect differential reliance on arithmetic fact retrieval during problem solving. The aim of the present functional magnetic resonance imaging study was to investigate the brain correlates of mathematical competence in a task requiring the processing of typical mathematical representations. Twenty-eight adults of lower and higher mathematical competence worked on a representation matching task in which they had to evaluate whether the numerical information of a symbolic equation matches that of a bar chart. Two task conditions without and one condition with arithmetic demands were administered. Both competence groups performed equally well in the non-arithmetic conditions and only differed in accuracy in the condition requiring calculation. Activation contrasts between the groups revealed consistently stronger left AG activation in the more competent individuals across all three task conditions. The finding of competence-related activation differences independently of arithmetic demands suggests that more and less competent individuals differ in a cognitive process other than arithmetic fact retrieval. Specifically, it is argued that the stronger left AG activity in the more competent adults may reflect their higher proficiency in processing mathematical symbols. Moreover, the study demonstrates competence-related parietal activation differences that were not accompanied by differential experimental performance. PMID:22069387

Grabner, Roland H; Reishofer, Gernot; Koschutnig, Karl; Ebner, Franz

2011-01-01

332

Brain Correlates of Mathematical Competence in Processing Mathematical Representations  

PubMed Central

The ability to extract numerical information from different representation formats (e.g., equations, tables, or diagrams) is a key component of mathematical competence but little is known about its neural correlate. Previous studies comparing mathematically less and more competent adults have focused on mental arithmetic and reported differences in left angular gyrus (AG) activity which were interpreted to reflect differential reliance on arithmetic fact retrieval during problem solving. The aim of the present functional magnetic resonance imaging study was to investigate the brain correlates of mathematical competence in a task requiring the processing of typical mathematical representations. Twenty-eight adults of lower and higher mathematical competence worked on a representation matching task in which they had to evaluate whether the numerical information of a symbolic equation matches that of a bar chart. Two task conditions without and one condition with arithmetic demands were administered. Both competence groups performed equally well in the non-arithmetic conditions and only differed in accuracy in the condition requiring calculation. Activation contrasts between the groups revealed consistently stronger left AG activation in the more competent individuals across all three task conditions. The finding of competence-related activation differences independently of arithmetic demands suggests that more and less competent individuals differ in a cognitive process other than arithmetic fact retrieval. Specifically, it is argued that the stronger left AG activity in the more competent adults may reflect their higher proficiency in processing mathematical symbols. Moreover, the study demonstrates competence-related parietal activation differences that were not accompanied by differential experimental performance. PMID:22069387

Grabner, Roland H.; Reishofer, Gernot; Koschutnig, Karl; Ebner, Franz

2011-01-01

333

Research on Method of Non-stationary Vibration Signals Processing of Heavy Vehicle Gear Case Bearing  

Microsoft Academic Search

The vibration signals in gear case shifting process is nonstationary signals. The ways which dispose stationary signals can't be used for nonstationary signals effectively. And because of the complexity of gear case, bearing fault signals is hard to pick up because of violent background noise. This article adopts the method of equal-angle sampling, transforming frequency changing signals in time-domain into

Wang Wei; Wang Ping; Yang Tongqiang

2007-01-01

334

SVD and higher-order statistical processing of human nerve signals  

Microsoft Academic Search

Human afferent whole nerve signals recorded using an implanted nerve-cuff electrode were analyzed using two algorithms based on the statistical properties of the signals. The processing method typically described in the literature (Rectification and Bin-Integration-RBI) has serious shortcomings in processing these signals, which have very poor signal-to-noise ratios. Algorithms based on a Singular Value Decomposition (SVD) of the signal's 2nd

Barry Upshaw; T. Sinkjaer

1996-01-01

335

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

336

Signal Processing Track Assoc. Prof. idem Erolu Erdem  

E-print Network

, such as a painting, it's a continuous signal. If the picture is a digital image, it's a discrete signal. Video: The motion of a particle through some space can be considered to be a signal, or can be represented by Wiener Filtering Compression Reduce the storage size on disk Faster transmission over internet, wireless

Ã?nay, Devrim

337

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 first 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-X510 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

338

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

339

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

340

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

341

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

342

[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

343

Playback of beyond high definition video signal in holographic data storage system with wavefront compensation and parallel signal processing  

NASA Astrophysics Data System (ADS)

We have developed a holographic data storage system that can demonstrate real-time playback of beyond high definition video signals. In the proposed system, to increase the data-transfer rate of the reproduced data, we focused on improving the SNR of the reproduced data and on improving the signal processing speed, which the SNR of the reproduced data has a significant effect on. One of the factors that deteriorate the SNR is shrinkage in the medium. This shrinkage distorts recorded holograms and degrades the quality of the reproduced data. We investigated wavefront compensation as a means to improve the SNR of reproduced data degraded by hologram distortion and found that controlling the defocus component of the reference beam is effective. We have also been developing parallel signal processing to increase the data-transfer rate. We placed three GPUs in the signal processing unit: one for the reproduced data detection from the reconstructed image and two for the LDPC decoding for error correction of the reproduced data. The LDPC decoding required a lot more time than the data detection, so we designed a signal processing in which detected data in the GPU for the data detection were sent to the two GPUs for the LDPC decoding alternatively. We implemented wavefront compensation for the defocus component and developed parallel signal processing with three GPUs for our holographic data storage system. Using this system, we demonstrated real-time playback of beyond high definition video signals with 50 Mbps.

Muroi, Tetsuhiko; Kinoshita, Nobuhiro; Ishii, Norihiko; Kamijo, Koji; Kikuchi, Hiroshi

2014-09-01

344

Neural Correlates of Affect Processing and Aggression in Methamphetamine Dependence  

PubMed Central

Context Methamphetamine abuse is associated with high rates of aggression, but few studies have addressed the contributing neurobiological factors. Objective To quantify aggression, investigate function of the amygdala and prefrontal cortex, and assess relationships between brain function and behavior in methamphetamine-dependent individuals. Design In a case-control study, aggression and brain activation were compared between methamphetamine-dependent and control participants. Setting Participants were recruited from the general community to an academic research center. Participants Thirty-nine methamphetamine-dependent volunteers (16 women) who were abstinent for 7 to 10 days and 37 drug-free control volunteers (18 women) participated in the study; subsets completed self-report and behavioral measures. Functional magnetic resonance imaging (fMRI) was performed on 25 methamphetamine-dependent and 23 control participants. Main outcome measures We measured self-reported and perpetrated aggression, and self-reported alexithymia. Brain activation was assessed using fMRI during visual processing of facial affect (affect matching), and symbolic processing (affect labeling), the latter representing an incidental form of emotion regulation. Results Methamphetamine-dependent participants self-reported more aggression and alexithymia than control participants and escalated perpetrated aggression more following provocation. Alexithymia scores correlated with measures of aggression. During affect matching, fMRI showed no differences between groups in amygdala activation, but found lower activation in methamphetamine-dependent than control participants in bilateral ventral inferior frontal gyrus. During affect labeling, participants recruited dorsal inferior frontal gyrus and exhibited decreased amygdala activity, consistent with successful emotion regulation; there was no group difference in this effect. The magnitude of decrease in amygdala activity during affect labeling correlated inversely with self-reported aggression in control participants, and perpetrated aggression in all participants. Ventral inferior frontal gyrus activation correlated inversely with alexithymia in control participants. Conclusions Contrary to the hypotheses, methamphetamine-dependent individuals may successfully regulate emotions through incidental means (affect labeling). Instead, low ventral inferior frontal gyrus activity may contribute to heightened aggression by limiting emotional insight. PMID:21041607

Payer, Doris E.; Lieberman, Matthew D.; London, Edythe D.

2012-01-01

345

Memory Processes in the Response of Plants to Environmental Signals  

PubMed Central

Plants are sensitive to stimuli from the environment (e.g., wind, rain, contact, pricking, wounding). They usually respond to such stimuli by metabolic or morphogenetic changes. Sometimes the information corresponding to a stimulus may be “stored” in the plant where it remains inactive until a second stimulus “recalls” this information and finally allows it to take effect. Two experimental systems have proved especially useful in unravelling the main features of these memory-like processes. In the system based on Bidens seedlings, an asymmetrical treatment (e.g., pricking, or gently rubbing one of the seedling cotyledons) causes the cotyledonary buds to grow asymmetrically after release of apical dominance by decapitation of the seedlings. This information may be stored within the seedlings, without taking effect, for at least two weeks; then the information may be recalled by subjecting the seedlings to a second, appropriate, treatment that permits transduction of the signal into the final response (differential growth of the buds). Whilst storage is an irreversible, all-or-nothing process, recall is sensitive to a number of factors, including the intensity of these factors, and can readily be enabled or disabled. In consequence, it is possible to recall the stored message several times successively. In the system based on flax seedlings, stimulation such as manipulation stimulus, drought, wind, cold shock and radiation from a GSM telephone or from a 105 GHz Gunn oscillator, has no apparent effect. If, however, the seedlings are subjected at the same time to transient calcium depletion, numerous epidermal meristems form in their hypocotyls. When the calcium depletion treatment is applied a few days after the mechanical treatment, the time taken for the meristems to appear is increased by a number of days exactly equal to that between the application of the mechanical treatment and the beginning of the calcium depletion treatment. This means that a meristem-production information corresponding to the stimulation treatment has been stored in the plants, without any apparent effect, until the calcium depletion treatment recalls this information to allow it to take effect. Gel electrophoresis has shown that a few protein spots are changed (pI shift, appearance or disappearance of a spot) as a consequence of the application of the treatments that store or recall a meristem-production signal in flax seedlings. A SIMS investigation has revealed that the pI shift of one of these spots is probably due to protein phosphorylation. Modifications of the proteome have also been observed in Arabidopsis seedlings subjected to stimuli such as cold shock or radiation from a GSM telephone. PMID:19521470

Tafforeau, M; Verdus, M C; Norris, V; Ripoll, C

2006-01-01

346

Demonstration and evaluation of all-optical digital-to-analog conversion using pulse pattern recognition based on optical correlation processing  

Microsoft Academic Search

We demonstrate and evaluate the all-optical digital-to-analog conversion using pulse pattern recognition based on optical correlation processing. Experimental results show that four-bit digital signals with 1.65 ps interval can be successfully converted to analog signals

T. Nishitani; T. Konishi; K. Itoh; H. Furukawa

2006-01-01

347

Neural Correlates of Semantic Competition during Processing of Ambiguous Words  

PubMed Central

The current study investigated the neural correlates that underlie the processing of ambiguous words and the potential effects of semantic competition on that processing. Participants performed speeded lexical decisions on semantically related and unrelated prime-target pairs presented in the auditory modality. The primes were either ambiguous words (e.g., ball) or unambiguous words (e.g., athlete), and targets were either semantically related to the dominant (i.e., most frequent) meaning of the ambiguous prime word (e.g., soccer) or to the subordinate (i.e., less frequent) meaning (e.g., dance). Results showed increased activation in the bilateral inferior frontal gyrus (IFG) for ambiguous related compared to unambiguous related stimulus pairs, demonstrating that prefrontal areas are activated even in an implicit task where participants are not required to explicitly analyze the semantic content of the stimuli and to make an overt selection of a particular meaning based on this analysis. Additionally, increased activation was found in the left IFG and the left cingulate gyrus for subordinate meaning compared to dominant meaning conditions, suggesting that additional resources are recruited in order to resolve increased competition demands in accessing the subordinate meaning of an ambiguous word. PMID:18702579

Bilenko, Natalia Y.; Grindrod, Christopher M.; Myers, Emily B.; Blumstein, Sheila E.

2010-01-01

348

KATP channels process nucleotide signals in muscle thermogenic response  

PubMed Central

Uniquely gated by intracellular adenine nucleotides, sarcolemmal ATP-sensitive K+ (KATP) channels have been typically assigned to protective cellular responses under severe energy insults. More recently, KATP channels have been instituted in the continuous control of muscle energy expenditure under non-stressed, physiological states. These advances raised the question of how KATP channels can process trends in cellular energetics within a milieu where each metabolic system is set to buffer nucleotide pools. Unveiling the mechanistic basis of the KATP channel-driven thermogenic response in muscles thus invites the concepts of intracellular compartmentalization of energy and proteins, along with nucleotide signaling over diffusion barriers. Furthermore, it requires gaining insight into the properties of reversibility of intrinsic ATPase activity associated with KATP channel complexes. Notwithstanding the operational paradigm, the homeostatic role of sarcolemmal KATP channels can be now broadened to a wider range of environmental cues affecting metabolic well-being. In this way, under conditions of energy deficit such as ischemic insult or adrenergic stress, the operation of KATP channel complexes would result in protective energy saving, safeguarding muscle performance and integrity. Under energy surplus, downregulation of KATP channel function may find potential implications in conditions of energy imbalance linked to obesity, cold intolerance and associated metabolic disorders. PMID:20925594

Reyes, Santiago; Park, Sungjo; Terzic, Andre; Alekseev, Alexey E.

2014-01-01

349

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

350

A New Digital Signal Processing Method for Spectrum Interference Monitoring  

NASA Astrophysics Data System (ADS)

Frequency spectrum is a limited shared resource, nowadays interested by an ever growing number of different applications. Generally, the companies providing such services pay to the governments the right of using a limited portion of the spectrum, consequently they would be assured that the licensed radio spectrum resource is not interested by significant external interferences. At the same time, they have to guarantee that their devices make an efficient use of the spectrum and meet the electromagnetic compatibility regulations. Therefore the competent authorities are called to control the access to the spectrum adopting suitable management and monitoring policies, as well as the manufacturers have to periodically verify the correct working of their apparatuses. Several measurement solutions are present on the market. They generally refer to real-time spectrum analyzers and measurement receivers. Both of them are characterized by good metrological accuracies but show costs, dimensions and weights that make no possible a use "on the field". The paper presents a first step in realizing a digital signal processing based measurement instrument able to suitably accomplish for the above mentioned needs. In particular the attention has been given to the DSP based measurement section of the instrument. To these aims an innovative measurement method for spectrum monitoring and management is proposed in this paper. It performs an efficient sequential analysis based on a sample by sample digital processing. Three main issues are in particular pursued: (i) measurement performance comparable to that exhibited by other methods proposed in literature; (ii) fast measurement time, (iii) easy implementation on cost-effective measurement hardware.

Angrisani, L.; Capriglione, D.; Ferrigno, L.; Miele, G.

2011-01-01

351

FPGA-based signal processing in an optical feedback self-mixing interferometry system  

Microsoft Academic Search

Optical feedback Self-mixing Interferometry (OFSMI) can achieve a high-resolution displacement sensing and measurement by using advanced digital signal processing. However, most existing signal processing algorithms used for OFSMI signals are implemented on a PC by Matlab or other programming languages. In this case, the whole structure of OFSMI sensing system is incompact and the measurement is in low speed. The

Zongzhen Li; Yanguang Yu; Jiangtao Xi; Huiying Ye

2010-01-01

352

RESEARCH STATEMENT My research lies in mathematical signal processing, random matrix theory, frame theory, geometric  

E-print Network

. Sigma-Delta quantization ­ Past work 2.1. Motivation. In signal processing, analog to digital conversion processing concerning analog-to-digital conversion of bandlimited signals. 1. Introduction and summary Master's degree in UBC, I worked on Sigma-Delta quantization which is an active research area in signal

Rauhut, Holger

353

Fourier analysis and signal processing by use of the Mobius inversion formula  

Microsoft Academic Search

A novel Fourier technique for digital signal processing is developed. This approach to Fourier analysis is based on the number-theoretic method of the Mobius inversion of series. The Fourier transform method developed is shown also to yield the convolution of two signals. A computer simulation shows that this method for finding Fourier coefficients is quite suitable for digital signal processing.

I. S. Reed; D. W. Tufts; X. Yu; T. K. Truong; M.-T. Shih; X. Yin

1990-01-01

354

Material and process optimization of correlated electron random access memories  

NASA Astrophysics Data System (ADS)

A method of making transition metal oxide materials that result in resistive switching properties stable over time and temperature is described. We have developed an ultra low temperature (?450°C) process for carbonyl ligand modified NiO thin films based on the chemical solution deposition (CSD) for correlated electron random access memory (CeRAM) applications. CeRAMs form the general class of devices that use the electron-electron interaction as the primary mode of operation. These devices are fabricated in the conductive state (born-ON), thus, they do not require electroforming to enter the variable resistance state. Several process parameters such as film stoichiometry, thickness, annealing temperature and ambient have been investigated to optimize CeRAMs properties. We present the coordination number `fine tuning' in NiO ultra thin films via carbonyl ligand doping that regulate the number of oxygen vacancies and the surface excess of metal ions. CeRAMs contrary to just standard NiO based resistive memories use the pure Mott-like charge transfer insulator in which an abrupt metal to insulator transition is the dominant mechanism without the aid of charge trapping vacancies. In our films the effect of the oxygen vacancies are canceled due to the stabilizing effect of the carbonyl based extrinsic ligand. In this paper, detailed process sequence and the extrinsic ligand doping scheme is described in some length. It is shown that complexes formed by the introduction of the extrinsic ligand promote Ni2+ ions to enter the disproportionation reaction Ni2+ + Ni2+?Ni1+ + Ni3+ which is considered to be responsible for the memory mechanism.

Celinska, Jolanta; McWilliams, Christopher; Paz de Araujo, Carlos; Xue, Kan-Hao

2011-05-01

355

Saliency Processing and Obesity: A Preliminary Imaging Study of the Stop Signal Task  

PubMed Central

Obesity has been associated with altered cerebral functions including cognitive control. The stop signal task (SST) has been widely used to study cognitive control by producing high conflict stop trials among many low conflict go trials. Contrasting these stop trials with go trials provides a measure of saliency processing and response inhibition. By comparing functional magnetic resonance images of obese (BMI >30) and lean (BMI <22) females performing the SST, we observed differences in regional brain activations despite similar behavioral performance between groups. Specifically, lean females had greater activations in the insula, inferior parietal cortex, cuneus, and supplementary motor area than obese females during stop as compared to go trials. This difference was caused by diminished brain activations in obese females in stop as compared to go trials. Furthermore, the brain activations in these regions inversely correlated to BMI across subjects. These preliminary findings suggest altered neural processes of cognitive control in obesity. PMID:21720427

Hendrick, Olivia M.; Luo, Xi; Zhang, Sheng; Li, Chiang-shan R.

2013-01-01

356

A SIGNAL PROCESSING ARCHITECTURE BASED ON RAM TECHNOLOGY Jim Torresen  

E-print Network

to program the look-up table. Ex- periments have been undertaken for prosthetic hand control. The results appropriate application for this approach is prosthetic hand control ­ operated by electromyography (EMG) signals (Scott and Parker, 1988). The signals from the remaining part of the arm are of limited resolution

Torresen, Jim

357

EGR valve control signal processing for internal combustion engine  

SciTech Connect

An EGR valve control signal developed by the EGR modulator circuit for controlling the EGR valve is combined in a feedback loop with a signal representative of an engine combustion condition, e.g. engine knock, to modify ignition timing through advance or retard.

Gardner, C.O.

1982-02-16

358

EGR valve control signal processing for internal combustion engine  

Microsoft Academic Search

An EGR valve control signal developed by the EGR modulator circuit for controlling the EGR valve is combined in a feedback loop with a signal representative of an engine combustion condition, e.g. engine knock, to modify ignition timing through advance or retard.

1982-01-01

359

Receptor clustering and signal processing in E. coli chemotaxis  

Microsoft Academic Search

Chemotaxis in Escherichia coli is one of the most thoroughly studied model systems for signal transduc- tion. Receptor-kinase complexes, organized in clusters at the cell poles, sense chemoeffector stimuli and transmit signals to flagellar motors by phosphorylation of a diffusible response regulator protein. Despite the appar- entsimplicityofthesignaltransductionpathway,thehigh sensitivity, wide dynamic range and integration of multiple stimuli of this pathway remain

Victor Sourjik

2004-01-01

360

Digital Signal Processing Techniques for the GIFTS SM EDU  

NASA Astrophysics Data System (ADS)

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, J.; Reisse, R.; Gazarik, M.

361

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

362

Signal Interpretation of Multifunction Radars: Modeling and Statistical Signal Processing With Stochastic Context Free Grammar  

Microsoft Academic Search

Multifunction radars (MFRs) are sophisticated sensors with complex dynamical modes that are widely used in surveillance and tracking. Because of their agility, a new solution to the interpretation of radar signal is critical to aircraft survivability and successful mission completion. The MFRs' three main characteristics that make their signal interpretation challenging are: i) MFRs' behavior is mission dependent, that is,

Alex Wang; Vikram Krishnamurthy

2008-01-01

363

Design of a dataway processor for a parallel image signal processing system  

Microsoft Academic Search

Recently, demands for high-speed signal processing have been increasing especially in the field of image data compression, computer graphics, and medical imaging. To achieve sufficient power for real-time image processing, we have been developing parallel signal-processing systems. This paper describes a communication processor called 'dataway processor' designed for a new scalable parallel signal-processing system. The processor has six high-speed communication

Mitsuru Nomura; Tetsurou Fujii; Sadayasu Ono

1995-01-01

364

The expression of Wnt-1 inducible signaling pathway protein-2 in astrocytoma: Correlation between pathological grade and clinical outcome  

PubMed Central

Wnt-1 inducible signaling pathway protein-2 (WISP-2) is a member of the CCN family, which is critical for the control of cell morphology, motion, adhesion and other processes involved in tumorigenesis. The expression pattern and clinical significance of WISP-2 in astrocytomas remains unclear. In this study, reverse transcription-polymerase chain reaction was performed to systematically investigate the expression of WISP-2 in 47 astrocytoma tissues of different pathological grades and 10 normal brain tissues. The mRNA expression levels of WISP-2 in the astrocytoma tissues were observed to be significantly higher than those in the normal brain tissues. Furthermore, the upregulation of WISP-2 was found to be associated with astrocytomas of higher pathological grades. Subsequently, 154 astrocytoma and 15 normal brain tissues were analyzed using immunohistochemistry and similar results were obtained. Univariate and multivariate survival analyses were used to determine the correlations between WISP-2 expression and overall survival (OS) and progression-free survival (PFS). The results indicated that the expression of WISP-2 was found to negatively correlate with patient PFS and OS. These results demonstrated that the WISP-2 protein is involved in the pathogenesis and progression of human astrocytomas and may serve as a malignant biomarker of this disease.

XIAO, GELEI; TANG, ZHI; YUAN, XIANRUI; YUAN, JIAN; ZHAO, JIE; ZHANG, ZHIPING; HE, ZHENGWEN; LIU, JINGPING

2015-01-01

365

Processing of acoustic signals in grasshoppers - A neuroethological approach towards female choice.  

PubMed

Acoustic communication is a major factor for mate attraction in many grasshopper species and thus plays a vital role in a grasshopper's life. First of all, the recognition of the species-specific sound patterns is crucial for preventing hybridization with other species, which would result in a drastic fitness loss. In addition, there is evidence that females are choosy with respect to conspecific males and prefer or reject the songs of some individuals, thereby exerting a sexual selection on males. Remarkably, the preferences of females are preserved even under masking noise. To discriminate between the basically similar signals of conspecifics is obviously a challenge for small nervous systems. We therefore ask how the acoustic signals are processed and represented in the grasshopper's nervous system, to allow for a fine discrimination and assessment of individual songs. The discrimination of similar signals may be impeded not only by signal masking due to external noise sources, but also by intrinsic noise due to the inherent variability of spike trains. Using a spike train metric we could estimate how well, in principle, the songs of different individuals can be discriminated on the basis of neuronal responses, and found a remarkable potential for discrimination performance at the first stage, but not on higher stages of the auditory pathway. Next, we ask which benefits a grasshopper female may earn from being choosy. New results, which revealed correlations between specific song features and the size and immunocompetence of the males, suggest that females may derive from acoustic signals clues about condition and health of the sending male. However, we observed substantial differences between the preference functions of individual females and it may be particularly rewarding to relate the variations in female preferences to individual differences in the responses of identified neurons. PMID:22728472

Ronacher, Bernhard; Stange, Nicole

2013-01-01

366

Electrophysiological correlates of melodic processing in congenital amusia.  

PubMed

Music listening involves using previously internalized regularities to process incoming musical structures. A condition known as congenital amusia is characterized by musical difficulties, notably in the detection of gross musical violations. However, there has been increasing evidence that individuals with the disorder show preserved musical ability when probed using implicit methods. To further characterize the degree to which amusic individuals show evidence of latent sensitivity to musical structure, particularly in the context of stimuli that are ecologically valid, electrophysiological recordings were taken from a sample of amusic and control participants as they listened to real melodies. To encourage them to pay attention to the music, participants were asked to detect occasional notes in a different timbre. Using a computational model of auditory expectation to identify points of varying levels of expectedness in these melodies (in units of information content (IC), a measure which has an inverse relationship with probability), ERP analysis investigated the extent to which the amusic brain differs from that of controls when processing notes of high IC (low probability) as compared to low IC ones (high probability). The data revealed a novel effect that was highly comparable in both groups: Notes with high IC reliably elicited a delayed P2 component relative to notes with low IC, suggesting that amusic individuals, like controls, found these notes more difficult to evaluate. However, notes with high IC were also characterized by an early frontal negativity in controls that was attenuated in amusic individuals. A correlation of this early negative effect with the ability to make accurate note expectedness judgments (previous data collected from a subset of the current sample) was shown to be present in typical individuals but compromised in individuals with amusia: a finding in line with evidence of a close relationship between the amplitude of such a response and explicit knowledge of musical deviance. PMID:23707539

Omigie, Diana; Pearce, Marcus T; Williamson, Victoria J; Stewart, Lauren

2013-08-01

367

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

368

Signal, noise, and resolution in correlated fluctuations from snapshot small-angle x-ray scattering  

SciTech Connect

It has been suggested that the three-dimensional structure of one particle may be reconstructed using the scattering from many identical, randomly oriented copies ab initio, without modeling or a priori information. This may be possible if these particles are frozen in either space or time, so that the conventional two-dimensional small-angle x-ray scattering (SAXS) distribution contains fluctuations and is no longer isotropic. We consider the magnitude of the correlated fluctuation SAXS (CFSAXS) signal for typical x-ray free-electron laser (XFEL) beam conditions and compare this against the errors derived with the inclusion of Poisson photon counting statistics. The resulting signal-to-noise ratio (SNR) is found to rapidly approach a limit independent of the number of particles contributing to each diffraction pattern, so that the addition of more particles to a ''single-particle-per-shot'' experiment may be of little value, apart from reducing solvent background. When the scattering power is significantly less than one photon per particle per Shannon pixel, the SNR grows in proportion to incident flux. We provide simulations for protein molecules in support of these analytical results, and discuss the effects of solvent background scatter. We consider the SNR dependence on resolution and particle size, and discuss the application of the method to glasses and liquids, and the implications of more powerful XFELs, smaller focused beams, and higher pulse repetition rates for this approach. We find that an accurate CFSAXS measurement may be acquired to subnanometer resolution for protein molecules if a 9-keV beam containing 10{sup 13} photons is focused to a {approx}100-nm spot diameter, provided that the effects of solvent background can be reduced sufficiently.

Kirian, Richard A.; Schmidt, Kevin E.; Wang Xiaoyu; Doak, R. Bruce; Spence, John C. H. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

2011-07-15

369

Signal, noise, and resolution in correlated fluctuations from snapshot small-angle x-ray scattering  

NASA Astrophysics Data System (ADS)

It has been suggested that the three-dimensional structure of one particle may be reconstructed using the scattering from many identical, randomly oriented copies ab initio, without modeling or a priori information. This may be possible if these particles are frozen in either space or time, so that the conventional two-dimensional small-angle x-ray scattering (SAXS) distribution contains fluctuations and is no longer isotropic. We consider the magnitude of the correlated fluctuation SAXS (CFSAXS) signal for typical x-ray free-electron laser (XFEL) beam conditions and compare this against the errors derived with the inclusion of Poisson photon counting statistics. The resulting signal-to-noise ratio (SNR) is found to rapidly approach a limit independent of the number of particles contributing to each diffraction pattern, so that the addition of more particles to a “single-particle-per-shot” experiment may be of little value, apart from reducing solvent background. When the scattering power is significantly less than one photon per particle per Shannon pixel, the SNR grows in proportion to incident flux. We provide simulations for protein molecules in support of these analytical results, and discuss the effects of solvent background scatter. We consider the SNR dependence on resolution and particle size, and discuss the application of the method to glasses and liquids, and the implications of more powerful XFELs, smaller focused beams, and higher pulse repetition rates for this approach. We find that an accurate CFSAXS measurement may be acquired to subnanometer resolution for protein molecules if a 9-keV beam containing 1013 photons is focused to a ˜100-nm spot diameter, provided that the effects of solvent background can be reduced sufficiently.

Kirian, Richard A.; Schmidt, Kevin E.; Wang, Xiaoyu; Doak, R. Bruce; Spence, John C. H.

2011-07-01

370

The electronic architecture and dynamic signal processing capabilities of an artificial dendritic tree which can be used to process and classify dynamic signals is described. The electrical circuit  

E-print Network

dendritic tree which can be used to process and classify dynamic signals is described. The electrical circuit architecture is modeled after neurons that have spatially extensive dendritic trees. The artificial dendritic tree is a hybrid VLSI circuit and is sensitive to both temporal and spatial signal

Delaware, University of

371

Low cost analog signal processing for massive radio telescope arrays  

E-print Network

Measurement and analysis of redshifted 21cm hydrogen emissions is a developing technique for studying the early universe. The primary time of interest corresponds to a signal in the the 100-200MHz frequency band. The ...

Kunz, Eben A

2012-01-01

372

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

373

Signal processing and decision making in single cells  

E-print Network

Cells are not simple passive observers oblivious to their environment, but sense and adapt to environmental changes in order to thrive. In addition to sensing the presence of signals in the environment, cells can extract ...

Mettetal, Jerome Thomas, II

2008-01-01

374

Roles of phosphotase 2A in nociceptive signal processing.  

PubMed

Multiple protein kinases affect the responses of dorsal horn neurons through phosphorylation of synaptic receptors and proteins involved in intracellular signal transduction pathways, and the consequences of this modulation may be spinal central sensitization. In contrast, the phosphatases catalyze an opposing reaction of de-phosphorylation, which may also modulate the functions of crucial proteins in signaling nociception. This is an important mechanism in the regulation of intracellular signal transduction pathways in nociceptive neurons. Accumulated evidence has shown that phosphatase 2A (PP2A), a serine/threonine specific phosphatase, is implicated in synaptic plasticity of the central nervous system and central sensitization of nociception. Therefore, targeting protein phosphotase 2A may provide an effective and novel strategy for the treatment of clinical pain. This review will characterize the structure and functional regulation of neuronal PP2A and bring together recent advances on the modulation of PP2A in targeted downstream substrates and relevant multiple nociceptive signaling molecules. PMID:24010880

Wang, Yun; Lei, Yongzhong; Fang, Li; Mu, Yonggao; Wu, Jing; Zhang, Xuan

2013-01-01

375

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

376

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

377

RF phase modulation of optical signals and optical/electrical signal processing  

E-print Network

Analog RF phase modulation of optical signals has been a topic of interest for many years, mainly focusing on Intensity Modulation Direct Detection (IMDD). The virtues of coherent detection combined with the advantages of ...

Andrikogiannopoulos, Nikolas I

2006-01-01

378

Measuring and Utilizing the Correlation Between Signal Connectivity and Signal Positioning for FPGAs Containing MultiBit Building Blocks  

Microsoft Academic Search

As the logic capacity of field-programmable gate arrays (FPGAs) increases, there has been a corresponding increase in the variety of FPGA building blocks. From a mere collection of conventional logic blocks, FPGAs can now include digital signal processors, multipliers, multi- bit addressable memory cells and even processor cores. One of the common characteristics of these new building blocks is their

Andy Gean Ye; Jonathan Rose

2005-01-01

379

Coherent demodulation of optical multilevel phase-shift-keying signals using homodyne detection and digital signal processing  

Microsoft Academic Search

We demonstrate coherent demodulation of optical multilevel (M-ary) phase-shift-keying (PSK) signals. Since the carrier phase is estimated accurately through digital signal processing after phase-diversity homodyne detection, the system performance is highly tolerant to the carrier phase noise. By off-line bit-error-rate measurements using distributed feedback semiconductor lasers with linewidths of 150 kHz as a transmitter and a local oscillator, it is

Satoshi Tsukamoto; Kazuhiro Katoh; Kazuro Kikuchi

2006-01-01

380

Characterization of the correlation between collagen fibril thickness and forward and backward second harmonic signal  

NASA Astrophysics Data System (ADS)

Optical-based microscopy plays an important role in various scientific fields such as physics, chemistry and biology. Second harmonic generation (SHG) microscopy has become one of the indispensable tools for biomedical imaging for the last decade because the signal generated from SHG is sensitive to the objective structure and this amazing non-invasive method can also directly observe the objective without using extra fluorescent labels, especially for collagen molecules. As the most abundant protein in animals, collagen is responsible for a number of important structural and functional roles in vertebrates. For certain diseases, it has been shown that collagen fiber diameter has a significant variation and thus as a vital symptom for diagnosis. Moreover, collagen diameter is also a key parameter for fibrogenesis studying. Therefore, the determination of collagen fiber diameter is important for studying biophysical processes and identifying bioengineering applications. In this study, we investigated various collagen fibril thicknesses and the corresponding forward (FSHG) and backward (BSHG) second harmonic signal intensity variation. Our result exhibits that SHG intensity can quantify describe the relative collagen fibril thickness alteration, which also indicates the coherent effect difference between FSHG and BSHG. This approach demonstrates the capability of SHG imaging in providing collagen mechanical information and that may be applied in the evaluation of advancing collagen issues in vivo.

Hsueh, Chiu-Mei; Hovhannisyan, Vladimir A.; Dong, Chen-Yuan

2011-07-01

381

Correlation  

Microsoft Academic Search

Reviews 16 publications (1913-1914) based on the problem of correlations. Correlation is viewed as a means of solving the problem of development and the traits that are affected. The uses of correlations are also discussed. A high correlation does not signify good quality of the two factors. A more intensive study of the factors influencing correlation is recommended. Cites a

James Burt Miner

1914-01-01

382

Correlation  

Microsoft Academic Search

Reviews 38 studies on statistical correlation (1913-1916). Several studies have tried to explain and investigate Spearman's theory of general and specific mental factors in terms of correlation. The interpretation of correlation through heredity has also been discussed by investigators. A number of methods such as partial and multiple correlations, variant difference correlation method, and several others have been devised. The

James Burt Miner

1916-01-01

383

IEEE SIGNAL PROCESSING MAGAZINE [84] MARCH 2009 he field of audio forensics involves many topics  

E-print Network

IEEE SIGNAL PROCESSING MAGAZINE [84] MARCH 2009 T he field of audio forensics involves many topics- falls encountered by signal processing experts when dealing with typical forensic material due processing research field. HISTORY Over the preceding 40 years, forensic audio examination has gradually

Maher, Robert C.

384

IEEE SIGNAL PROCESSING MAGAZINE [61] JULY 2011 obile phones have evolved into powerful  

E-print Network

IEEE SIGNAL PROCESSING MAGAZINE [61] JULY 2011 M obile phones have evolved into powerful image (CDs), real estate, print media, or artworks. First deployments of such systems include Google Goggles PUBLISHING & PHOTODISC #12;IEEE SIGNAL PROCESSING MAGAZINE [62] JULY 2011 The mobile client processes

Girod, Bernd

385

Functional correlates of optic flow motion processing in Parkinson's disease  

PubMed Central

The visual input created by the relative motion between an individual and the environment, also called optic flow, influences the sense of self-motion, postural orientation, veering of gait, and visuospatial cognition. An optic flow network comprising visual motion areas V6, V3A, and MT+, as well as visuo-vestibular areas including posterior insula vestibular cortex (PIVC) and cingulate sulcus visual area (CSv), has been described as uniquely selective for parsing egomotion depth cues in humans. Individuals with Parkinson’s disease (PD) have known behavioral deficits in optic flow perception and visuospatial cognition compared to age- and education-matched control adults (MC). The present study used functional magnetic resonance imaging (fMRI) to investigate neural correlates related to impaired optic flow perception in PD. We conducted fMRI on 40 non-demented participants (23 PD and 17 MC) during passive viewing of simulated optic flow motion and random motion. We hypothesized that compared to the MC group, PD participants would show abnormal neural activity in regions comprising this optic flow network. MC participants showed robust activation across all regions in the optic flow network, consistent with studies in young adults, suggesting intact optic flow perception at the neural level in healthy aging. PD participants showed diminished activity compared to MC particularly within visual motion area MT+ and the visuo-vestibular region CSv. Further, activation in visuo-vestibular region CSv was associated with disease severity. These findings suggest that behavioral reports of impaired optic flow perception and visuospatial performance may be a result of impaired neural processing within visual motion and visuo-vestibular regions in PD. PMID:25071484

Putcha, Deepti; Ross, Robert S.; Rosen, Maya L.; Norton, Daniel J.; Cronin-Golomb, Alice; Somers, David C.; Stern, Chantal E.

2014-01-01

386

Functional correlates of optic flow motion processing in Parkinson's disease.  

PubMed

The visual input created by the relative motion between an individual and the environment, also called optic flow, influences the sense of self-motion, postural orientation, veering of gait, and visuospatial cognition. An optic flow network comprising visual motion areas V6, V3A, and MT+, as well as visuo-vestibular areas including posterior insula vestibular cortex (PIVC) and cingulate sulcus visual area (CSv), has been described as uniquely selective for parsing egomotion depth cues in humans. Individuals with Parkinson's disease (PD) have known behavioral deficits in optic flow perception and visuospatial cognition compared to age- and education-matched control adults (MC). The present study used functional magnetic resonance imaging (fMRI) to investigate neural correlates related to impaired optic flow perception in PD. We conducted fMRI on 40 non-demented participants (23 PD and 17 MC) during passive viewing of simulated optic flow motion and random motion. We hypothesized that compared to the MC group, PD participants would show abnormal neural activity in regions comprising this optic flow network. MC participants showed robust activation across all regions in the optic flow network, consistent with studies in young adults, suggesting intact optic flow perception at the neural level in healthy aging. PD participants showed diminished activity compared to MC particularly within visual motion area MT+ and the visuo-vestibular region CSv. Further, activation in visuo-vestibular region CSv was associated with disease severity. These findings suggest that behavioral reports of impaired optic flow perception and visuospatial performance may be a result of impaired neural processing within visual motion and visuo-vestibular regions in PD. PMID:25071484

Putcha, Deepti; Ross, Robert S; Rosen, Maya L; Norton, Daniel J; Cronin-Golomb, Alice; Somers, David C; Stern, Chantal E

2014-01-01

387

A Research on the Relation Between the Integrated Three-Pulse Photon Echo Signal and the Correlation Function  

NASA Astrophysics Data System (ADS)

The photon echo phenomenon has been described and proven with classical theory. In this paper, in order to calculate the three-pulse photon echo signal, we treat the vibration of material molecules as the model of the multimode Brownian oscillator (MBO). Using the correlation function, we can calculate the linear function, the time response function, and the third-order nonlinear polarization; then we can obtain the three-pulse photon echo signal. After that, we numerically simulate the three-pulse photon echo signal by changing the contribution ratios of these four kinds of vibration in the MBO model and setting the coherence time (t12) or the population time (t23) equal to zero. Finally, we analyze the result and find that these three laser pulses are not in time coincidence completely when the signal reaches a maximum. In addition, the location of the peak signal intensity will vary if the oscillating regime of the material molecules changes.

Zhang, Zhonghua; Chen, Jia; Zhao, Yang; Xia, Yuangin

2014-03-01

388

Optogenetic drive of neocortical pyramidal neurons generates fMRI signals that are correlated with spiking activity  

PubMed Central

Local fluctuations in the blood oxygenation level-dependent (BOLD) signal serve as the basis of functional magnetic resonance imaging (fMRI). Understanding the correlation between distinct aspects of neural activity and the BOLD response is fundamental to the interpretation of this widely used mapping signal. Analysis of this question requires the ability to precisely manipulate the activity of defined neurons. To achieve such control, we combined optogenetic drive of neocortical neurons with high-resolution (9.4 T) rodent fMRI and detailed analysis of neurophysiological data. Light-driven activation of pyramidal neurons resulted in a positive BOLD response at the stimulated site. To help differentiate the neurophysiological correlate(s) of the BOLD response, we employed light trains of the same average frequency, but with periodic and Poisson distributed pulse times. These different types of pulse trains generated dissociable patterns of single-unit, multi-unit and local field potential (LFP) activity, and of BOLD signals. The BOLD activity exhibited the strongest correlation to spiking activity with increasing rates of stimulation, and, to a first approximation, was linear with pulse delivery rate, while LFP activity showed a weaker correlation. These data provide an example of a strong correlation between spike rate and the BOLD response. PMID:23523914

Kahn, I.; Knoblich, U.; Desai, M.; Bernstein, J.; Graybiel, A.M.; Boyden, E.S.; Buckner, R.L.; Moore, C.I.

2013-01-01

389

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

390

Statistical tests for power-law cross-correlated processes.  

PubMed

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. PMID:22304166

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

2011-12-01

391

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

392

Multiresolution Markov Models for Signal and Image Processing  

E-print Network

on graphical models. Keywords--Autoregressive processes, Bayesian networks, data assimilation, data fusion- hancement, image processing, image segmentation, inverse prob- lems, Kalman filtering, machine vision processing, sparse matrices, state space methods, stochastic realization, trees, wavelet transforms

Willsky, Alan S.

393

Analog processing of signals from a CZT strip detector with orthogonal coplanar anodes  

Microsoft Academic Search

We present the requirements, design, and performance of an analog circuit for processing the non-collecting anode strip signals from a cadmium zinc telluride (CZT) strip detector with orthogonal coplanar anodes. Detector signal simulations and measurements with a prototype are used to define the range of signal characteristics as a function of location of the gamma interaction in the detector. The

Kipp Larson; Valentin T. Jordanov; Mark L. McConnell; John R. Macri; James M. Ryan; Allen Drake; Louis-Andre Hamel; Olivier Tousignant

2000-01-01

394

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

395

Rapid Prototyping of High Performance Signal Processing Applications  

NASA Astrophysics Data System (ADS)

Advances in embedded systems for digital signal processing (DSP) are enabling many scientific projects and commercial applications. At the same time, these applications are key to driving advances in many important kinds of computing platforms. In this region of high performance DSP, rapid prototyping is critical for faster time-to-market (e.g., in the wireless communications industry) or time-to-science (e.g., in radio astronomy). DSP system architectures have evolved from being based on application specific integrated circuits (ASICs) to incorporate reconfigurable off-the-shelf field programmable gate arrays (FPGAs), the latest multiprocessors such as graphics processing units (GPUs), or heterogeneous combinations of such devices. We, thus, have a vast design space to explore based on performance trade-offs, and expanded by the multitude of possibilities for target platforms. In order to allow systematic design space exploration, and develop scalable and portable prototypes, model based design tools are increasingly used in design and implementation of embedded systems. These tools allow scalable high-level representations, model based semantics for analysis and optimization, and portable implementations that can be verified at higher levels of abstractions and targeted toward multiple platforms for implementation. The designer can experiment using such tools at an early stage in the design cycle, and employ the latest hardware at later stages. In this thesis, we have focused on dataflow-based approaches for rapid DSP system prototyping. This thesis contributes to various aspects of dataflow-based design flows and tools as follows: 1. We have introduced the concept of topological patterns, which exploits commonly found repetitive patterns in DSP algorithms to allow scalable, concise, and parameterizable representations of large scale dataflow graphs in high-level languages. We have shown how an underlying design tool can systematically exploit a high-level application specification consisting of topological patterns in various aspects of the design flow. 2. We have formulated the core functional dataflow (CFDF) model of computation, which can be used to model a wide variety of deterministic dynamic dataflow behaviors. We have also presented key features of the CFDF model and tools based on these features. These tools provide support for heterogeneous dataflow behaviors, an intuitive and common framework for functional specification, support for functional simulation, portability from several existing dataflow models to CFDF, integrated emphasis on minimally-restricted specification of actor functionality, and support for efficient static, quasi-static, and dynamic scheduling techniques. 3. We have developed a generalized scheduling technique for CFDF graphs based on decomposition of a CFDF graph into static graphs that interact at run-time. Furthermore, we have refined this generalized scheduling technique using a new notion of "mode grouping," which better exposes the underlying static behavior. We have also developed a scheduling technique for a class of dynamic applications that generates parameterized looped schedules (PLSs), which can handle dynamic dataflow behavior without major limitations on compile-time predictability. 4. We have demonstrated the use of dataflow-based approaches for design and implementation of radio astronomy DSP systems using an application example of a tunable digital downconverter (TDD) for spectrometers. Design and implementation of this module has been an integral part of this thesis work. This thesis demonstrates a design flow that consists of a high-level software prototype, analysis, and simulation using the dataflow interchange format (DIF) tool, and integration of this design with the existing tool flow for the target implementation on an FPGA platform, called interconnect break-out board (IBOB). We have also explored the trade-off between low hardware cost for fixed configurations of digital downconverters and flexibility offered by TDD designs. 5. This thesis has contri

Sane, Nimish

396

Silicon technology compatible photonic molecules for compact optical signal processing  

SciTech Connect

Photonic molecules (PMs) based on multiple inner coupled microring resonators allow to surpass the fundamental constraint between the total quality factor (Q{sub T}), free spectral range (FSR), and resonator size. In this work, we use a PM that presents doublets and triplets resonance splitting, all with high Q{sub T}. We demonstrate the use of the doublet splitting for 34.2?GHz signal extraction by filtering the sidebands of a modulated optical signal. We also demonstrate that very compact optical modulators operating 2.75 times beyond its resonator linewidth limit may be obtained using the PM triplet splitting, with separation of ?55?GHz.

Barea, Luis A. M., E-mail: barea@ifi.unicamp.br; Vallini, Felipe; Jarschel, Paulo F.; Frateschi, Newton C. [Device Research Laboratory, Applied Physics Department, “GlebWataghin” Physics Institute, University of Campinas–UNICAMP, 13083-859 Campinas, SP (Brazil)] [Device Research Laboratory, Applied Physics Department, “GlebWataghin” Physics Institute, University of Campinas–UNICAMP, 13083-859 Campinas, SP (Brazil)

2013-11-11

397

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

398

A broad band signal processing technique for miniature low-finesse Fabry-Pérot interferometric sensors  

NASA Astrophysics Data System (ADS)

A simple signal processing technique for interrogating miniature low finesse Fabry-Pérot interferometric sensors is reported. The technique enables broadband signals to be recovered at their fundamental frequency for signal amplitudes up to ?. The technique is demonstrated using a dual wavelength source, derived from a multimode laser diode, to obtain quadrature outputs from an ? 20 ?m cavity, which are processed using analogue electronics. The signal to noise ratio is ? 65 dB / Hz at 250 Hz for a 0.6 rad displacement of the mirror, which results in a minimum detectable signal of ? 300 ?rad Hz. Broadband signal recovery is demonstrated by recovering simultaneously applied signals of 150 Hz and 250 Hz which results in a signal to noise ratio of ? 45 dB / Hz, and recovery of a triangular waveform applied to the mirror.

Potter, J.; Ezbiri, A.; Tatam, R. P.

1997-02-01

399

Beating nyquist through correlations: A constrained random demodulator for sampling of sparse bandlimited signals  

Microsoft Academic Search

Technological constraints severely limit the rate at which analog-todigital converters can reliably sample signals. Recently, Tropp et al. proposed an architecture, termed the random demodulator (RD), that attempts to overcome this obstacle for sparse bandlimited signals. One integral component of the RD architecture is a white noiselike, bipolar modulating waveform that changes polarity at a rate equal to the signal

Andrew Harms; Waheed U. Bajwa; Robert Calderbank

2011-01-01

400

Downregulation of Notch1 and its potential correlation with epidermal growth factor receptor signalling in tongue squamous cell carcinoma  

Microsoft Academic Search

We investigated the expression of Notch1 in human oral squamous cell carcinoma (SCC) and explored its potential correlation with epidermal growth factor receptor (EGFR) signalling in oral SCC. Paraffin sections of primary SCC of the tongue and normal mucosa were screened immunohistochemically for Notch1 and EGFR proteins. Human SCC of the tongue Tca8113 cells were treated with AG1478 to block

Hong-jie Huang; Fei-yun Ping; Ji-an Hu; Shi-fang Zhao

2010-01-01

401

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

402

Multiresolution Signal Processing on Meshes for Automatic Pathological Shape Characterization  

E-print Network

present a method based on multiresolution signal pro- cessing on meshes to create a thickness atlas. We applied this method to construct an atlas of bladder wall thickness. Bladder cancer is associated with increased bladder wall thickness. A thickness atlas helps to detect abnormal thickening in the bladder wall

Sylvain Jaume

403

Wide-band array signal processing via spectral smoothing  

NASA Technical Reports Server (NTRS)

A novel algorithm for the estimation of direction-of-arrivals (DOA) of multiple wide-band sources via spectral smoothing is presented. The proposed algorithm does not require an initial DOA estimate or a specific signal model. The advantages of replacing the MUSIC search with an ESPRIT search are discussed.

Xu, Guanghan; Kailath, Thomas

1989-01-01

404

Robust Stimulus Encoding in Olfactory Processing: Hyperacuity and Ecient Signal  

E-print Network

of this #12; turnover of receptors on signal transmission. The key issue here is how the ol- factory system of perception. Receptor adaptation or fatigue is a key factor here and is known to occur in ORNs as their response adapts strongly during exposure to high levels of speci#12;c chemicals or repeated exposure[3

Pearce, Tim C.

405

Adaptive beamforming for array signal processing in aeroacoustic measurements  

E-print Network

) Phased microphone arrays have become an important tool in the localization of noise sources. INTRODUCTION Beamforming techniques with microphone arrays1�3 are increasingly being used in the aerospace techniques.9 Beamforming is a technique that uses a sensor array to visualize the location of a signal

Huang, Xun

406

Social Signal Processing in Companion Systems -Challenges Ahead  

E-print Network

suggests that nonverbal interaction plays a key role in steering, controlling and maintaining social interaction between humans. We seek to transfer fragments of this competence to the domain of human computer interaction. Some core computational mechanisms of extracting and analyzing nonverbal signals are presented

407

Topics in radar signal processing. I - Overview and coherent processing techniques  

NASA Astrophysics Data System (ADS)

A survey is presented of some of the principal processing features of a modern pulsed search radar. Emphasis is placed on system considerations and performance characteristics, the A/D conversion process being the only hardware aspect addressed. It is noted that this operation is the key to transforming analog IF radar signals into an accurate equivalent complex digital representation. Attention is given to matched filters and pulse compression and to clutter rejection, with descriptions given of moving target indicators and pulse Doppler processors. It is pointed out that many techniques which in the past have been considered too cumbersome or impractical to implement can now be included at reasonable levels of complexity and cost.

Hansen, V. G.

1984-03-01

408

EEL 6502 Adaptive Signal Processing 1. Catalog Description (3 credits) Theory of adaptation with stationary signals;  

E-print Network

with stationary signals; performance measures. LMS, RLS algorithms. Implementation issues and applications. 2. Pre, performance measures and the implementation of adaptive algorithms. Both the LMS and the RLS will be covered-090126-1 e. Software: MATLAB 13. Recommended Reading - a. Title: b. Author: c. Publication date and edition

Fang, Yuguang "Michael"

409

The cross correlation between the 21-cm radiation and the CMB lensing field: a new cosmological signal  

SciTech Connect

The measurement of Baryon Acoustic Oscillations through the 21-cm intensity mapping technique at redshift z {<=} 4 has the potential to tightly constrain the evolution of dark energy. Crucial to this experimental effort is the determination of the biasing relation connecting fluctuations in the density of neutral hydrogen (HI) with the ones of the underlying dark matter field. In this work I show how the HI bias relevant to these 21-cm intensity mapping experiments can successfully be measured by cross-correlating their signal with the lensing signal obtained from CMB observations. In particular I show that combining CMB lensing maps from Planck with 21-cm field measurements carried out with an instrument similar to the Cylindrical Radio Telescope, this cross-correlation signal can be detected with a signal-to-noise (S/N) ratio of more than 5. Breaking down the signal arising from different redshift bins of thickness {Delta}z = 0.1, this signal leads to constraining the large scale neutral hydrogen bias and its evolution to 4{sigma} level.

Vallinotto, Alberto [Los Alamos National Laboratory

2011-01-01

410

Increased BOLD signal in the fusiform gyrus during implicit emotion processing in anorexia nervosa?  

PubMed Central

Background The behavioural literature in anorexia nervosa (AN) has suggested impairments in psychosocial functioning and studies using facial expression processing tasks (FEPT) have reported poorer recognition and slower identification of emotions. Methods Functional magnetic resonance imaging (fMRI) was used alongside a FEPT, depicting neutral, mildly happy and happy faces, to examine the neural correlates of implicit emotion processing in AN. Participants were instructed to specify the gender of the faces. Levels of depression, anxiety, obsessive–compulsive symptoms and eating disorder behaviour were obtained and principal component analysis (PCA) was performed to acquire uncorrelated variables. Results fMRI analysis revealed a greater blood-oxygenation level dependent (BOLD) response in AN in the right fusiform gyrus to all facial expressions. This response showed a linear increase with the happiness of the facial expression and was found to be stronger in those not taking medication. PCA analysis revealed a single component indicating a greater level of general clinical symptoms. Conclusion Neuroimaging findings would suggest that alterations in implicit emotion processing in AN occur during early perceptual processing of social signals and illustrate greater engagement on the FEPT. The lack of separate components using PCA suggests that the questionnaires used might not be suited as predictive measures. PMID:24501698

Fonville, Leon; Giampietro, Vincent; Surguladze, Simon; Williams, Steven; Tchanturia, Kate

2013-01-01

411

Broadband mode in proton-precession magnetometers with signal processing regression methods  

NASA Astrophysics Data System (ADS)

The choice of the signal processing method may improve characteristics of the measuring device. We consider the measurement error of signal processing regression methods for a quasi-harmonic signal generated in a frequency selective device. The results are applied to analyze the difference between the simple period meter processing and regression algorithms using measurement cycle signal data in proton-precession magnetometers. Dependences of the measurement error on the sensor quality factor and frequency of nuclear precession are obtained. It is shown that regression methods considerably widen the registration bandwidth and relax the requirements on the magnetometer hardware, and thus affect the optimization criteria of the registration system.

Denisov, Alexey Y.; Sapunov, Vladimir A.; Rubinstein, Boris

2014-05-01

412

Regulation of PrPC signaling and processing by dimerization  

PubMed Central

The cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored protein present at the cell surface. PrPC N-terminal moiety is intrinsically disordered and is able to interact with a variety of ligands. Physiological ligands have neurotrophic activity, whilst others, including protein toxic oligomers, have neurotoxic functions. These two opposite activities involve different interacting partners and result from different PrPC-activated signaling pathways. Remarkably, PrPC may be inactivated either by physiological endoproteolysis and release of the N-terminal domain, or by ectodomain shedding. Ligand-induced PrPC dimerization or enforced dimerization of PrPC indicate that PrPC dimerization represents an important molecular switch for both intracellular signaling and inactivation by the release of PrPC N-terminal domain or shedding. In this review, we summarize evidence that cell surface receptor activity of PrPC is finely regulated by dimerization. PMID:25364762

Roucou, Xavier

2014-01-01

413

Processing of Signals from Fiber Bragg Gratings Using Unbalanced Interferometers  

NASA Technical Reports Server (NTRS)

Fiber Bragg gratings (FBG) have become preferred sensory structures in fiber optic sensing system. High sensitivity, embedability, and multiplexing capabilities make FBGs superior to other sensor configurations. The main feature of FBGs is that they respond in the wavelength domain with the wavelength of the returned signal as the indicator of the measured parameter. The wavelength is then converted to optical intensity by a photodetector to detect corresponding changes in intensity. This wavelength-to-intensity conversion is a crucial part in any FBG-based sensing system. Among the various types of wavelength-to-intensity converters, unbalanced interferometers are especially attractive because of their small weight and volume, lack of moving parts, easy integration, and good stability. In this paper we investigate the applicability of unbalanced interferometers to analyze signals reflected from Bragg gratings. Analytical and experimental data are presented.

Adamovsky, Grigory; Juergens, Jeff; Floyd, Bertram

2005-01-01

414

Signal Processing and Computational Model for Neural Networks Chen, Houjin Yuan, Baozong  

E-print Network

Signal Processing and Computational Model for Neural Networks Chen, Houjin Yuan, Baozong Institute processing, Computational model, Computer Simulation; 1. Introduction Neural networks have the ability properties and one computer simulation system for neural networks was designed and implemented. In order

Byrne, John H.

415

A Preferential Design Approach for Energy-Efficient and Robust Implantable Neural Signal Processing Hardware  

E-print Network

in real time. Such a computational task for online neural data processing requires an innovative circuit- croprocessor or Digital Signal Processing (DSP) chips would dissipate too much power and are too large in size

Bhunia, Swarup

416

Method And Aparatus For Improving Resolution In Spectrometers Processing Output Steps From Non-Ideal Signal Sources  

DOEpatents

A method and apparatus for processing step-like output signals generated by non-ideal, nominally single-pole ("N-1P") devices responding to possibly time-varying, pulse-like input signals of finite duration, wherein the goal is to recover the integrated areas of the input signals. Particular applications include processing step-like signals generated by detector systems in response to absorbed radiation or particles and, more particularly, to digitally processing such step-like signals in high resolution, high rate gamma ray (.gamma.-ray) spectrometers with resistive feedback preamplifiers connected to large volume germanium detectors. Superconducting bolometers can be similarly treated. The method comprises attaching a set of one or more filters to the device's (e.g., preamplifier's) output, capturing a correlated multiple output sample from the filter set in response to a detected event, and forming a weighted sum of the sample values to accurately recover the total area (e.g., charge) of the detected event.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025); Momayezi, Michael (San Francisco, CA)

2003-07-01

417

Fixed-point C language for digital signal processing  

Microsoft Academic Search

Fixed-point C language is proposed for convenient and efficient programming of fixed-point digital signal processors. This language has a `fix' data type that can have an individual integer wordlength according to the range of a variable. It can add or subtract two data having different integer wordlengths by automatically inserting shift operations. The accuracy of the fixed-point multiply operation is

Wonyong Sung; Jiyang Kang

1995-01-01

418

Audio Signal Processing Based on Sinusoidal Analysis\\/Synthesis  

Microsoft Academic Search

Based on a sinusoidal model, an analysis\\/synthesis technique is developed that characterizes audio signals, such as speech\\u000a and music, in terms of the amplitudes, frequencies, and phases of the component sine waves. These parameters are estimated\\u000a by applying a peak-picking algorithm to the short-time Fourier transform of the input waveform. Rapid changes in the highly\\u000a resolved spectral components are tracked

T. F. Quatieri; R. J. Mcaulay

419

High-precision laser vibrometers based on digital Doppler signal processing  

Microsoft Academic Search

Recent developments in the field of digital signal processing (DSP) hardware and affordable powerful PC platforms enable the realization of a new generation of laser-Doppler vibrometers, providing outstanding measurement accuracy and resolution. The paper presents both PC based and DSP based solutions for digital Doppler signal processing, utilized within the latest vibrometer models introduced by Polytec GmbH, Waldbronn. It is

Martin Bauer; F. Ritter; Georg Siegmund

2002-01-01

420

A STATISTICAL SIGNAL PROCESSING APPROACH TO IMAGE FUSION FOR CONCELED WEAPON DETECTION1  

E-print Network

A STATISTICAL SIGNAL PROCESSING APPROACH TO IMAGE FUSION FOR CONCELED WEAPON DETECTION1 J. Yang A statistical signal processing approach to multisensor image fusion is presented for concealed weapon detection of this approach by applying this method to fusion of visual and non-visual images with emphasis on CWD

Blum, Rick

421

Signal Processing 59 (1997) 43-59 ECG data compression by spline approximation  

E-print Network

SIGN& PROCESSING Signal Processing 59 (1997) 43-59 ECG data compression by spline approximation transform method for ECG data compression based on B-spline basis functions is proposed. The algorithm allows these basis functions to adapt their shape to the nonstationary behavior of ECG signals

Gabbouj, Moncef

422

Simulated phase-locking stimulation: An improved signal processing strategy for cochlear implant  

Microsoft Academic Search

Electrical stimulation of the auditory pathway produces different patterns of neural activity than those acoustically elicited. Traditional signal-processing strategies for cochlear implant usually do not utilize phase information contained in sound waves. Here, to evaluate potential advantages of introducing phase information to cochlear implant devices, a new signal processing method, so called simulated phase-locking stimulation (SPLS), was developed. To convey

Xihong Wu; Hongwei Qu; Jing Chen; Tianshu Qu; Liang Li

2005-01-01

423

Signal Processing for Cochlear Prosthesis: A Tutorial Review Philipos C. Loizou  

E-print Network

, and signal processing. Signal processing, in par- ticular, played an important role in the development of di electrodes that is inserted into the cochlea by a surgeon Figure 1. In single-channel implants only one are stimulated, they re and propagate neural impulses to the brain. The brain interprets these impulses as sounds

Allen, Jont

424

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

E-print Network

New 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 approach and sets the requirements for the new approach. Once an architecture of the new solution

425

Digital Signal Processing 20 (2010) 8596 Contents lists available at ScienceDirect  

E-print Network

Digital Signal Processing 20 (2010) 85­96 Contents lists available at ScienceDirect Digital Signal Processing www.elsevier.com/locate/dsp Spectral efficiency of maximum ratio combining (MRC) over slow fading with estimation errors Fawaz S. Al-Qahtani a,, Salam A. Zummo b , Arun K. Gurung a , Zahir M. Hussain a a School

Zummo, Salam Adel

426

MONITORING NETWORK STRUCTURE AND CONTENT QUALITY OF SIGNAL PROCESSING ARTICLES ON WIKIPEDIA  

E-print Network

MONITORING NETWORK STRUCTURE AND CONTENT QUALITY OF SIGNAL PROCESSING ARTICLES ON WIKIPEDIA Tao C the network struc- ture and content quality of Signal Processing (SP) articles on Wikipedia. Using metrics to quantify the importance and quality of articles, we generate a list of SP articles on Wikipedia arranged

Vetterli, Martin

427

BINAURAL AND MULTIPLE-MICROPHONE SIGNAL PROCESSING MOTIVATED BY AUDITORY PERCEPTION  

E-print Network

BINAURAL AND MULTIPLE-MICROPHONE SIGNAL PROCESSING MOTIVATED BY AUDITORY PERCEPTION Richard M USA rms@cs.cmu.edu ABSTRACT It is well known that binaural processing is very useful for sep- arating version of the desired signal is developed using binaural principles, in the extent to which spe- cific

Stern, Richard

428

INVESTIGATING SIGNAL PROCESSING THEORY WITH MATHEMATICA Brian L. Evans and James H. McClellan  

E-print Network

INVESTIGATING SIGNAL PROCESSING THEORY WITH MATHEMATICA Brian L. Evans and James H. Mc We present extensions to the computer algebra and multimediaenvironmentMathematica toenable stu. The lower level is a set of Mathematica programs called the Signal Processing Packages SPP that implement

Evans, Brian L.

429

Helicopter-borne SAR Imaging Processing of Chirp-stepped Signal  

Microsoft Academic Search

In this paper, the processing algorithm of high resolution range profile of chirp-stepped signal is studied in the view of system, and the process of chirp-stepped signal SAR imaging on helicopter platform is analyzed. Furthermore, technology difficulties of helicopter-borne SAR imaging are showed, and imaging results are presented by experimental data

Hong Xiangru Zhang Tao; Du Zicheng

2006-01-01

430

Nanotechnology for genomic signal processing in cancer research - A focus on the genomic signal processing hardware design of the nanotools for cancer ressearch  

Microsoft Academic Search

Nanotechnology has recently been applied to study dynamic cellular processes, such as cell cycles and cell migration, providing rich spatial and temporal phenotype information. Tremendous opportunities and challenges exist in combining nanotechnology with signal processing techniques to develop faster, smaller, yet more accurate and sensitive biomedical devices for cancer genomics and proteomics to obtain a better understanding of the cellular

Jie Chen; Stephen T. C. Wong

2007-01-01

431

204 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 51, NO. 1, JANUARY 2003 Partial Likelihood for Signal Processing  

E-print Network

-theoretic connection, to show the equivalence of likelihood maximization and relative entropy minimization without than the traditional marginal or conditional likelihood (CL) type formu- lations used for most signal is the information-theoretic connection of likelihood to the fundamental information metric, relative entropy (or

Adali, Tulay

432

Processes of Sibling Influence in Adolescence: Individual and Family Correlates  

ERIC Educational Resources Information Center

This study examined the nature and correlates of adolescents' perceptions of sibling influence. Participants included 2 siblings (firstborn age M = 17.34; second-born age M = 14.76 years) from 191 maritally intact families. Adolescents' perceptions of sibling influence were measured via coded responses to open-ended questions about whether their…

Whiteman, Shawn D.; Christiansen, Abigail

2008-01-01

433

Correlation  

NSDL National Science Digital Library

The applets, created by Virginia Tech's Department of Statistics, allow you to see how different bivariate data look under different correlation structures. The "Movie" applet either creates data for a particular correlation or animates a multitude data sets ranging correlations from -1 to 1. The "Creation" applet allows the user to create a data set by adding or deleting points from the screen.

Anderson-Cook, C.; Dorai-Raj, S.; Robinson, T.

2009-09-14

434

Earthquake early warning system using real-time signal processing  

SciTech Connect

An earthquake warning system has been developed to provide a time series profile from which vital parameters such as the time until strong shaking begins, the intensity of the shaking, and the duration of the shaking, can be derived. Interaction of different types of ground motion and changes in the elastic properties of geological media throughout the propagation path result in a highly nonlinear function. We use neural networks to model these nonlinearities and develop learning techniques for the analysis of temporal precursors occurring in the emerging earthquake seismic signal. The warning system is designed to analyze the first-arrival from the three components of an earthquake signal and instantaneously provide a profile of impending ground motion, in as little as 0.3 sec after first ground motion is felt at the sensors. For each new data sample, at a rate of 25 samples per second, the complete profile of the earthquake is updated. The profile consists of a magnitude-related estimate as well as an estimate of the envelope of the complete earthquake signal. The envelope provides estimates of damage parameters, such as time until peak ground acceleration (PGA) and duration. The neural network based system is trained using seismogram data from more than 400 earthquakes recorded in southern California. The system has been implemented in hardware using silicon accelerometers and a standard microprocessor. The proposed warning units can be used for site-specific applications, distributed networks, or to enhance existing distributed networks. By producing accurate, and informative warnings, the system has the potential to significantly minimize the hazards of catastrophic ground motion. Detailed system design and performance issues, including error measurement in a simple warning scenario are discussed in detail.

Leach, R.R. Jr.; Dowla, F.U.

1996-02-01