Journal articles: 'Cross Correlation Peak'

1

Chen, Chulung, and Jian-Shuen Fang. "Cross-correlation peak optimization on joint transform correlators." Optics Communications 178, no. 4-6 (May 2000): 315–22. http://dx.doi.org/10.1016/s0030-4018(00)00683-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Mueller, Leonard J., Douglas W. Elliott, Garett M. Leskowitz, Jochem Struppe, Ryan A. Olsen, Kee-Chan Kim, and Christopher A. Reed. "Uniform-sign cross-peak double-quantum-filtered correlation spectroscopy." Journal of Magnetic Resonance 168, no. 2 (June 2004): 327–35. http://dx.doi.org/10.1016/j.jmr.2004.03.017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Jiang, Nan, and Jian Wang. "The Theoretical Limits of Watermark Spread Spectrum Sequence." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/432740.

Full text

Abstract:

At present, the spread spectrum (SS) sequences used in watermark include i.i.d. random sequences and the sequences used in SS communications. They appear earlier than digital watermark. Almost no researchers pay attention to whether they are really fit for watermark. In this paper, we compare the SS watermark channel and the traditional SS communication channel. We find out that their correlation property is different. Considering cropping and translation attacks, we define watermark auto- and cross-correlation and propose Loose Autocorrelation and Tight Cross-Correlation (LAC&TCC) properties for SS watermark. The LAC&TCC properties are that, whether or not synchronized, the autocorrelation is equal or close to 1 and the cross-correlation is equal or close to 0. Accordingly, the peak correlation is divided into the peak autocorrelationRa(l)and the peak cross-correlationRc(l). We establish the lower bound ofRc(l)and the higher bound ofRa(l), respectively. The two bounds indicate that, no matter how small the cover is reserved, the extractor can always find a threshold to distinguish auto- and cross-correlation in theory.

APA, Harvard, Vancouver, ISO, and other styles

4

Shim, J., S. Codis, C. Pichon, D. Pogosyan, and C. Cadiou. "The clustering of critical points in the evolving cosmic web." Monthly Notices of the Royal Astronomical Society 502, no. 3 (February 9, 2021): 3885–910. http://dx.doi.org/10.1093/mnras/stab263.

Full text

Abstract:

ABSTRACT Focusing on both small separations and baryonic acoustic oscillation scales, the cosmic evolution of the clustering properties of peak, void, wall, and filament-type critical points is measured using two-point correlation functions in ΛCDM dark matter simulations as a function of their relative rarity. A qualitative comparison to the corresponding theory for Gaussian random fields allows us to understand the following observed features: (i) the appearance of an exclusion zone at small separation, whose size depends both on rarity and signature (i.e. the number of negative eigenvalues) of the critical points involved; (ii) the amplification of the baryonic acoustic oscillation bump with rarity and its reversal for cross-correlations involving negatively biased critical points; (iii) the orientation-dependent small-separation divergence of the cross-correlations of peaks and filaments (respectively voids and walls) that reflects the relative loci of such points in the filament’s (respectively wall’s) eigenframe. The (cross-) correlations involving the most non-linear critical points (peaks, voids) display significant variation with redshift, while those involving less non-linear critical points seem mostly insensitive to redshift evolution, which should prove advantageous to model. The ratios of distances to the maxima of the peak-to-wall and peak-to-void over that of the peak-to-filament cross-correlation are ${\sim} \sqrt{2}$ and ${\sim} \sqrt{3}$, respectively, which could be interpreted as the cosmic crystal being on average close to a cubic lattice. The insensitivity to redshift evolution suggests that the absolute and relative clustering of critical points could become a topologically robust alternative to standard clustering techniques when analysing upcoming surveys such as Euclid or Large Synoptic Survey Telescope (LSST).

APA, Harvard, Vancouver, ISO, and other styles

5

Buckett, M. I., L. D. Marks, and D. E. Luzzi. "Correlation analysis of structure images." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 752–53. http://dx.doi.org/10.1017/s0424820100128079.

Full text

Abstract:

A typical high resolution structure image contains a large amount of intensity information which is masked by both statistical and amorphous noise. One useful method of quantifying such images is to employ correlation techniques. When one seeks to quantify the atom column positions, correlation techniques can be used to decompose the image into separate motifs (of specific peak amplitudes and positions - each motif corresponding to a single column of atoms), thereby reducing the data to a more manageable form.This problem can be considered as the least squares minimization of the function: where I(r) is the image, and m(r) is the motif, and the unknowns are the positions, rj, of the motifs and their peak heights, αj. The standard approach is to look for peaks in the cross-correlation (equation 2) between the motif and image, to determine rj and αj

APA, Harvard, Vancouver, ISO, and other styles

6

Adachi, M., T. Ohshima, S. Yamada, and T. Satoh. "Cross-correlation analysis of taste neuron pairs in rat solitary tract nucleus." Journal of Neurophysiology 62, no. 2 (August 1, 1989): 501–9. http://dx.doi.org/10.1152/jn.1989.62.2.501.

Full text

Abstract:

1. Experiments were conducted to examine the possibility that the taste-sensitive neurons with similar taste-selectivity are preferentially innervated by common driving neurons whose taste-selectivity is also similar. 2. Multiple microelectrodes, in most cases a pair of glued electrodes, were inserted into the unilateral solitary tract nucleus (NTS) of the rat, and simultaneous recordings were made in neuron pairs responding to the four basic taste stimuli. The spike response density (RD) of each neuron during tastant stimulation was determined. Correlation coefficients of spike occurrence were calculated for each neuron pair during application of tastants and distilled water and also during spontaneous background activity. The frequency of correlated discharge (FC) of a neuron pair was measured as the area of the peak appearing on the cross-correlogram (CC). The FC value was divided by the RD value to calculate the weight of the correlated discharges in the output of each neuron (WC value). 3. Eleven pairs showed peaks in the CC constructed during tastant stimulation, whereas in other 11 pairs no peaks were found. The cross-correlation-positive group with peaks was composed of 18 NaCl-best (responding most vigorously to NaCl) and 4 HCl-best neurons, whereas the negative group without peaks included 9 NaCl-best, 9 HCl-best, and 4 sucrose-best neurons. 4. In the cross-correlation-positive pairs the taste quality most effective for one of the component neurons was often (13 NaCl-best and 2 HCl-best, 15/22 = 0.681) identical to the taste quality giving the highest probability of correlated discharge, i.e., highest FC value, in the neuron pair. 5. There were five cross-correlation-positive pairs (5/11 = 0.455) in which both of the component neurons were NaCl-best and the FC value was highest during NaCl stimulation. 6. The CCs constructed during water application exhibited peaks for all the pairs which gave positive cross-correlation in response to stimulation with tastants, whereas all pairs with negative cross-correlation during tastant stimulation never gave a detectable peak during water application. 7. In three pairs of the cross-correlation-positive group, the CCs constructed during spontaneous background activity without application of any liquid showed a small peak. 8. During NaCl stimulation some neurons exhibited relatively high FC values, but the WC values were always low. In contrast, during sucrose stimulation, the FC value was always low, but the WC value was quite high in some neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

7

Marigheto, N., L. Venturi, D. Hibberd, K. M. Wright, G. Ferrante, and B. P. Hills. "Methods for peak assignment in low-resolution multidimensional NMR cross-correlation relaxometry." Journal of Magnetic Resonance 187, no. 2 (August 2007): 327–42. http://dx.doi.org/10.1016/j.jmr.2007.04.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Tomás, María-Baralida, Belén Ferrer, and David Mas. "Influence of Neighborhood Size and Cross-Correlation Peak-Fitting Method on Location Accuracy." Sensors 20, no. 22 (November 18, 2020): 6596. http://dx.doi.org/10.3390/s20226596.

Full text

Abstract:

A known technique to obtain subpixel resolution by using object tracking through cross-correlation consists of interpolating the obtained correlation function and then refining peak location. Although the technique provides accurate results, peak location is usually biased toward the closest integer coordinate. This effect is known as the peak-locking error and it strongly limits this calculation technique’s experimental accuracy. This error may differ depending on the scene and algorithm used to fit and interpolate the correlation peak, but in general, it may be attributed to a sampling problem and the presence of aliasing. Many studies in the literature analyze this effect in the Fourier domain. Here, we propose an alternative analysis on the spatial domain. According to our interpretation, the peak-locking error may be produced by a non-symmetrical sample distribution, thus provoking a bias in the result. According to this, the peak interpolant function, the size of the local domain and low-pass filters play a relevant role in diminishing the error. Our study explores these effects on different samples taken from the DIC Challenge database, and the results show that, in general, peak fitting with a Gaussian function on a relatively large domain provides the most accurate results.

APA, Harvard, Vancouver, ISO, and other styles

9

MA, CHUN-WANG, HUI-LING WEI, and YU-QI LI. "THE SYSTEMATIC BEHAVIOR IN THE FRAGMENTS OF THE CALCIUM ISOTOPES PROJECTILE FRAGMENTATION." International Journal of Modern Physics E 19, no. 08n09 (September 2010): 1545–52. http://dx.doi.org/10.1142/s0218301310015941.

Full text

Abstract:

We have calculated the cross sections of the fragments produced in the projectile fragmentation of the even 36–52 Ca isotopes using the statistical abrasion-ablation model. The isospin effect in the projectile fragmentation are studied by investigating the peak positions and the widths of the fragment isotopic cross section distributions. The peak positions of the fragments isotopic cross section distributions have good linear correlation to the Z of the fragments and the correlations are fitted using the linear function. The correlations between slopes b and the binding energies of the neutron ( S n) of the projectile nuclei, the differences between the binding energies of the neutron and proton( S n- S p) of the projectile nuclei and the neutron-skin thickness (δnp) are studied. It is found that b and δnp has a good linear correlation for the neutron-rich projectile nuclei.

APA, Harvard, Vancouver, ISO, and other styles

10

Chaves, C., C. Ibiapina, C. R. Andrade, R. Godinho, C. G. Alvim, and A. A. Cruz. "Correlation between peak nasal inspiratory flow and peak expiratory flow in children and adolescents." Rhinology journal 50, no. 4 (December 1, 2012): 381–85. http://dx.doi.org/10.4193/rhino12.073.

Full text

Abstract:

Background: PEAK nasal inspiratory flow (PNIF) has been proposed as a simple method to evaluate nasal patency. Asthma and allergic rhinitis are commonly associated, and lower airway assessment can provide information concerning an objective interpretation of nasal function. Aims: TO determine whether the PNIF is correlated with peak expiratory flow (PEF) in children and adolescents. Methods and results: Cross-sectional study carried out in healthy students randomly chosen in 14 public schools of the city of Belo Horizonte. PNIF and PEF were assessed for each subject as the following characteristics: gender, height, weight and age. We created a linear regression model to explain the PNIF, in which we included all the variables with a p value ≤ 0.25 in a univariate analysis, and to calculate the relationship between the maximum PNIF and maximum PEF by the Spearman correlation coefficient. In total, 297 healthy subjects, aged between six and eighteen years were evaluated. A positive and significant correlation between PNIF and PEF was found. Conclusions: PEF is predictive of PNIF. However, these measures evaluate two distinct segments of the airways and should be both obtained for a more precise assessment of airflow limitation.

APA, Harvard, Vancouver, ISO, and other styles

11

McKiernan, Brian J., Joanne K. Marcario, Jennifer Hill Karrer, and Paul D. Cheney. "Correlations Between Corticomotoneuronal (CM) Cell Postspike Effects and Cell-Target Muscle Covariation." Journal of Neurophysiology 83, no. 1 (January 1, 2000): 99–115. http://dx.doi.org/10.1152/jn.2000.83.1.99.

Full text

Abstract:

The presence of postspike facilitation (PSpF) in spike-triggered averages of electromyographic (EMG) activity provides a useful means of identifying cortical neurons with excitatory synaptic linkages to motoneurons. Similarly the presence of postspike suppression (PSpS) suggests the presence of underlying inhibitory synaptic linkages. The question we have addressed in this study concerns the extent to which the presence and strength of PSpF and PSpS from corticomotoneuronal (CM) cells correlates with the magnitude of covariation in activity of the CM cell and its target muscles. For this purpose, we have isolated cells during a reach and prehension task during which the activity of 24 individual proximal and distal forelimb muscles was recorded. These muscles show broad coactivation but with a highly fractionated and muscle specific fine structure of peaks and valleys. Covariation was assessed by computing long-term (2 s) cross-correlations between CM cells and forelimb muscles. The magnitude of cross-correlations was greater for muscles with facilitation effects than muscles lacking effects in spike-triggered averages. The results also demonstrate a significant relationship between the sign of the postspike effect (facilitation or suppression) and the presence of a peak or trough in the cross-correlation. Of all the target muscles with facilitation effects in spike-triggered averages (PSpF, PSpF with synchrony, or synchrony facilitation alone), 89.5% were associated with significant cross-correlation peaks, indicating positively covarying muscle and CM cell activity. Seven percent of facilitation effects were not associated with a significant effect in the cross-correlation, whereas only 3.4% of effects were associated with correlation troughs. In contrast, of all the muscles with suppression effects in spike-triggered averages, 38.9% were associated with significant troughs in the cross-correlation, indicating an inverse relation between CM cell and muscle activity consistent with the presence of suppression. Fifty-five percent of suppression effects was associated with correlation peaks, whereas 5.6% was not associated with a significant effect in the cross-correlation. Limiting the analysis to moderate and strong facilitation effects, the magnitude of PSpF was correlated weakly with the magnitude of the cell-muscle cross-correlation peak. Nevertheless, the results show that although many CM cell-target muscle pairs covary during the reach and prehension task in a way consistent with the sign and strength of the CM cell's synaptic effects on target motoneurons, many exceptions exist. The results are compatible with a model in which control of particular motoneuron pools reflects not only the summation of signals from many CM cells but also signals from additional descending, sensory afferent, and intrinsic spinal cord neurons. Any one neuron will make only a small contribution to the overall activity of the motoneuron pool. In view of this, it is not surprising that relationships between postspike effects and CM cell-target muscle covariation are relatively weak with many apparent incongruities.

APA, Harvard, Vancouver, ISO, and other styles

12

Yongqiang Yang, 杨永强, 杨玲珍 lingzhen Yang, 吕艺辉 Yihui Lü, 王娟芬 Juanfen Wang, and 张朝霞 Zhaoxia Zhang. "Foreign Object Detection in Intralipid Solution Using Cross-Correlation Peak of Chaotic Laser." Acta Optica Sinica 39, no. 6 (2019): 0614001. http://dx.doi.org/10.3788/aos201939.0614001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Li, Mi, Wenli Shen, Wenchen Li, Hao Li, Yanqiu Tang, Yuejiang Song, and Xuping Zhang. "Cross correlation peak-seeking technique of BOTDR based on the incomplete Brillouin spectrum." Optics Communications 438 (May 2019): 1–5. http://dx.doi.org/10.1016/j.optcom.2018.12.066.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Olsen, Michael G., and Ronald J. Adrian. "Measurement volume defined by peak-finding algorithms in cross-correlation particle image velocimetry." Measurement Science and Technology 12, no. 2 (January 18, 2001): N14—N16. http://dx.doi.org/10.1088/0957-0233/12/2/402.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Vosberg, V. R., W. Fischer, and W. Joe Quadakkers. "The Cross Correlation Method: A Useful Tool for Peak Shift Determination in XSE." Materials Science Forum 228-231 (July 1996): 73–76. http://dx.doi.org/10.4028/www.scientific.net/msf.228-231.73.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Liu, Fang, and Yongxin Feng. "A Main Peak Extraction Method for High-Order BOC Signals." Journal of Navigation 70, no. 5 (May 30, 2017): 1153–69. http://dx.doi.org/10.1017/s0373463317000261.

Full text

Abstract:

Binary Offset Carrier (BOC) modulation signals have been applied in Global Navigation Satellite Systems (GNSS) because they offer a higher positioning accuracy and higher multipath rejection. However, there is a drawback in that the autocorrelation functions have multiple side peaks, meaning that this technique also leads to the large main peak estimation error problem and a low correlation decision efficiency problem. In this paper, we propose a new Main Peak Extraction (MPE) method for high-order BOC signals to solve these problems. In the new method, the synthesis cross-correlation function is established, and the geometry graph is formatted to calculate the estimation main peak. We eliminate all side peaks and improve the main peak phase estimation precision under the condition that the sub-carrier phase is offset. The results of the simulation demonstrate that the new method can achieve better main peak decision efficiency, side peak cancellation ability and phase estimation performance than traditional methods.

APA, Harvard, Vancouver, ISO, and other styles

17

Subramanian, Visalakshi H., Aruna Chennakeshawaran, and Vijay Krishna Kumar. "Correlation between peak expiratory flow rate and pectoralis muscle length." International Journal of Research in Medical Sciences 8, no. 10 (September 24, 2020): 3643. http://dx.doi.org/10.18203/2320-6012.ijrms20204244.

Full text

Abstract:

Background: Peak expiratory flow rate (PEFR) is a measure of the maximum speed of exhalation after a deep inspiration. The peak expiratory flow is measured by a device named peak flow meter. This study concentrates on the correlation of the PEFR with the pectoral muscle length.Methods: It is a cross sectional study of 30 convenient samples based on gender distribution where the PEFR and pectoralis muscle length were measured in the subjects.Results: Statistical analysis shows that there is a significant correlation between right pectoralis major general muscle length and PEFR (p=0.030), left pectoralis major general muscle length and PEFR (p=0.014), right pectoralis major clavicular end muscle length with PEFR (p=0.010).Conclusions: There is a significant correlation between peak expiratory flow and pectoralis muscle length.

APA, Harvard, Vancouver, ISO, and other styles

18

Ariningsih, Desak Made Wahyu, I. Made Niko Winaya, and I. Wayan Gede Sutadarma. "THE CORRELATION BETWEEN OBESITY AND PEAK EXPIRATORY FLOW RATE CHILDREN AGE 8-12 YEARS OLD IN SARASWATI TABANAN PRIMARY SCHOOL." Majalah Ilmiah Fisioterapi Indonesia 6, no. 3 (September 15, 2018): 5. http://dx.doi.org/10.24843/mifi.2018.v06.i03.p02.

Full text

Abstract:

ABSTRACT The purpose of this study was to know correlation between obesity and peak expiratory flow rate in children. This study was done in April 2017. The design of the study was correlational with the cross-sectional method. The samples in this study were obesity children in Saraswati Tabanan primary school of 8-12 years old as many as 55 samples based on consecutive sampling technique. Based on Pearson Correlation test to determine the relationship between obesity with peak expiratory flow rates the results showed a moderate negative association between obesity with peak expiratory flow rates of children with p = 0,000 and r = -0.524. This shows that the higher value of BMI obesity category in children, the lower peak expiratory flow rate value is. The results of this study shows that there was a significant relationship with moderate correlation between obesity with peak expiratory flow rate of the 8-12 year old children at Saraswati Tabanan Primary School Keywords: obesity, peak expiratory flow rate, peak flow meter

APA, Harvard, Vancouver, ISO, and other styles

19

Devine, T. J., and J. B. Cohen. "Profile Fitting in Residual Stress Determination." Advances in X-ray Analysis 29 (1985): 89–101. http://dx.doi.org/10.1154/s0376030800010168.

Full text

Abstract:

Of major importance in the determination of residual stress via diffraction is the accuracy of the measurement of the scattering angle (2 θp) of a Bragg peak. This determines the accuracy of the interplanar (d) spacing and hence the strain and stress. In the U.S., the most commonly accepted method of determining peak position is a parabolic fit near the top of a peak. (While a diffraction peak is not parabolic, this is a satisfactory function near the maximum.) The error in this procedure has been derived and tested, and it has been shown that a multipoint fit with a least 7 points is rapid and as precise or more precise than the centroid, the bisector of the half width, or cross correlation, except for sharp peaks in which case the centroid or cross correlation are slightly better. Thus a parabolic fit is generally useful and, since a least-squares fit to this function is readily carried out on modem micro-processors, automatical of a stress measurement is possible, including evaluation of errors.

APA, Harvard, Vancouver, ISO, and other styles

20

Zhang, Yong Hong, Ming J. Zuo, and Xiao Dong Wang. "Crack Size Estimation Using a Combination of Cross Correlation and Phase Shift Correction in Ultrasonic Time-of-Flight Diffraction Method." Key Engineering Materials 413-414 (June 2009): 305–12. http://dx.doi.org/10.4028/www.scientific.net/kem.413-414.305.

Full text

Abstract:

The ultrasonic time-of-flight-diffraction (TOFD) detection method has been widely used in crack size assessment. The key issue in TOFD is to determine the arrival time of crack tip diffracted signal. In the traditional cross correlation method, the resulting maximum peak of cross correlation function between two signals indicates the time of flight between them. In practical ultrasonic measurement, the transmission wave may be distorted and phase shift may be introduced. This paper presents a method using cross correlation and phase shift correction to improve the accuracy of crack sizing in the TOFD framework. The resulting maximum peak of the cross correlation function between two signals combining with time delay introduced by phase shift determine the arrival time of diffracted signal. Experimental results are used to demonstrate the advantage of the proposed method.

APA, Harvard, Vancouver, ISO, and other styles

21

Eggermont, Jos J. "Sound-Induced Synchronization of Neural Activity Between and Within Three Auditory Cortical Areas." Journal of Neurophysiology 83, no. 5 (May 1, 2000): 2708–22. http://dx.doi.org/10.1152/jn.2000.83.5.2708.

Full text

Abstract:

Neural synchrony within and between auditory cortical fields is evaluated with respect to its potential role in feature binding and in the coding of tone and noise sound pressure level. Simultaneous recordings were made in 24 cats with either two electrodes in primary auditory cortex (AI) and one in anterior auditory field (AAF) or one electrode each in AI, AAF, and secondary auditory cortex. Cross-correlograms (CCHs) for 1-ms binwidth were calculated for tone pips, noise bursts, and silence (i.e., poststimulus) as a function of intensity level. Across stimuli and intensity levels the total percentage of significant stimulus onset CCHs was 62% and that of significant poststimulus CCHs was 58% of 1,868 pairs calculated for each condition. The cross-correlation coefficient to stimulus onsets was higher for single-electrode pairs than for dual-electrode pairs and higher for noise bursts compared with tone pips. The onset correlation for single-electrode pairs was only marginally larger than the poststimulus correlation. For pairs from electrodes across area boundaries, the onset correlations were a factor 3–4 higher than the poststimulus correlations. The within-AI dual-electrode peak correlation was higher than that across areas, especially for spontaneous conditions. Correlation strengths for between area pairs were independent of the difference in characteristic frequency (CF), thereby providing a mechanism of feature binding for broadband sounds. For noise-burst stimulation, the onset correlation for between area pairs was independent of stimulus intensity regardless the difference in CF. In contrast, for tone-pip stimulation a significant dependence on intensity level of the peak correlation strength was found for pairs involving AI and/or AAF with CF difference less than one octave. Across all areas, driven rate, between-area peak correlation strength, or a combination of the two did not predict stimulus intensity. However, between-area peak correlation strength performs better than firing rate to decide if a stimulus is present or absent.

APA, Harvard, Vancouver, ISO, and other styles

22

Nowak, L. G., M. H. J. Munk, A. C. James, P. Girard, and J. Bullier. "Cross-Correlation Study of the Temporal Interactions Between Areas V1 and V2 of the Macaque Monkey." Journal of Neurophysiology 81, no. 3 (March 1, 1999): 1057–74. http://dx.doi.org/10.1152/jn.1999.81.3.1057.

Full text

Abstract:

Cross-correlation study of the temporal interactions between areas V1 and V2 of the macaque monkey. Cross-correlation studies performed in cat visual cortex have shown that neurons in different cortical areas of the same hemisphere or in corresponding areas of opposite hemispheres tend to synchronize their activities. The presence of synchronization may be related to the parallel organization of the cat visual system, in which different cortical areas can be activated in parallel from the lateral geniculate nucleus. We wanted to determine whether interareal synchronization of firing can also be observed in the monkey, in which cortical areas are thought to be organized in a hierarchy spanning different levels. Cross-correlation histograms (CCHs) were calculated from pairs of single or pairs of multiunit activities simultaneously recorded in areas V1 and V2 of paralyzed and anesthetized macaque monkeys. Moving bars and flashed bars were used as stimuli. The shift predictor was calculated and subtracted from the raw CCH to reveal interactions of neuronal origin in isolation. Significant CCH peaks, indicating interactions of neuronal origin, were obtained in 11% of the dual single-unit recordings and 46% of the dual multiunit recordings with moving bars. The incidence of nonflat CCHs with flashed bars was 29 and 78%, respectively. For the pairs of recording sites where both flashed and moving stimuli were used, the incidences of significant CCHs were very similar. Three types of peaks were distinguished on the basis of their width at half-height: T (<16 ms), C (between 16 and 180 ms), and H peaks (>180 ms). T peaks were very rarely observed (<1% in single-unit recordings). H peaks were observed in 7–16% of the single-unit CCHs, and C peaks in 6–16%, depending on the stimulus used. C and H peaks were observed more often when the receptive fields were overlapping or distant by <2°. To test for the presence of synchronization between neurons in areas V1 and V2, we measured the position of the CCH peak with respect to the origin of the time axis of the CCH. Only in the case of a few T peaks did we find displaced peaks, indicating a possible drive of the V2 neuron by the simultaneously recorded V1 cell. All the other peaks were either centered on the origin or overlapped the origin of time with their upper halves. Thus similarly to what has been reported for the cat, neurons belonging to different cortical areas in the monkey tend to synchronize the time of emission of their action potentials with three different levels of temporal precision. For peaks calculated from flashed stimuli, we compared the peak position with the difference between latencies of V1 and V2 neurons. There was a clear correlation for single-unit pairs in the case of C peaks. Thus the position of a C peak on the time axis appears to reflect the order of visual activation of the correlated neurons. The coupling strength for H peaks was smaller during visual drive compared with spontaneous activity. On the contrary, C peaks were seen more often and were stronger during visual stimulation than during spontaneous activity. This suggests that C-type synchronization is associated with the processing of visual information. The origin of synchronized activity in a serially organized system is discussed.

APA, Harvard, Vancouver, ISO, and other styles

23

Kazemian, Mohsen. "Peak-to-Average Power Ratio Reduction Based on Cross- Correlation in Orthogonal Frequency Division Multiplexing Systems." Frontiers of Mechatronical Engineering 1, no. 1 (November 5, 2018): 87. http://dx.doi.org/10.18282/fme.v1i1.603.

Full text

Abstract:

<p>Three of the most important techniques of Peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems are Partial Transmit Sequence PAPR (PTS-PAPR), Selected Mapping PAPR (SLM-PAPR) and Cross-Correlation-PTS. This paper performs a complete analysis on these three techniques providing simulation and discussion of their performance on PAPR reduction and bit error rate (BER). Moreover, the comparison of these methods by using Saleh model amplifier in an OFDM system is provided. The results show that PTS-PAPR outperforms the Cross-Correlation-PTS in terms of PAPR performance while Cross-Correlation-PTS method is more efficient in BER reduction compared to PTS-PAPR and SLM-PAPR.</p>

APA, Harvard, Vancouver, ISO, and other styles

24

Gaskell, C. Martin, Anuradha P. Koratkar, and Linda S. Sparke. "Investigations of Broad Line Region Structure and Kinematics Using Variability." Symposium - International Astronomical Union 134 (1989): 93–95. http://dx.doi.org/10.1017/s0074180900140458.

Full text

Abstract:

Gaskell and Sparke (1986) showed that one can determine the sizes of BLRs more accurately that the mean sampling interval by cross-correlating the continuum flux time series with a line flux time series. The position of the peak in the cross-correlation function (CCF) and its shape give an indication of the BLR size. The technique is explained in detail in Gaskell and Peterson (1987). The widely propagated misunderstanding is that the method involves simply interpolating both time series and cross-correlating them (in which case the CCF is dominated by the cross-correlations of “made-up” data). Actually the method involves cross correlating the observed points in one time series (continuum, say) with the linear interpolations of the other series (line flux). The line flux time series must always be smoother than the continuum time series it is derived from. We have usually employed the method with the interpolation done both ways round and averaged them (to reduce errors due to the interpolation) and we can intercompare the two results (to investigate errors).

APA, Harvard, Vancouver, ISO, and other styles

25

Charonko, John J., and Pavlos P. Vlachos. "Estimation of uncertainty bounds for individual particle image velocimetry measurements from cross-correlation peak ratio." Measurement Science and Technology 24, no. 6 (April 26, 2013): 065301. http://dx.doi.org/10.1088/0957-0233/24/6/065301.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Krishnamurthy, V. V., and John E. Casida. "Long-range CH correlation 2D NMR spectroscopy 3—long-rangeJ modulation of cross-peak intensities." Magnetic Resonance in Chemistry 26, no. 5 (May 1988): 367–72. http://dx.doi.org/10.1002/mrc.1260260505.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Furfaro, M. E., N. Marigheto, G. K. Moates, K. Cross, M. L. Parker, K. W. Waldron, and B. P. Hills. "Multidimensional NMR cross-correlation relaxation study of carrot phloem and xylem. Part I: Peak assignment." Applied Magnetic Resonance 35, no. 4 (May 2009): 521–35. http://dx.doi.org/10.1007/s00723-009-0183-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Vojciechowski, A. S., E. V. Rodrigues, J. Melo Filho, L. H. Gallo, C. T. Silva, and A. R. Gomes. "CORRELATION BETWEEN PEAK TORQUE WITH THE CROSS-SECTIONAL AREA OF QUADRICEPS IN COMMUNITY OLDER WOMEN." Innovation in Aging 1, suppl_1 (June 30, 2017): 776. http://dx.doi.org/10.1093/geroni/igx004.2813.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Sun, Xiyan, Shaojie Song, Yuanfa Ji, Xingli Gan, Suqing Yan, and Xizi Jia. "An Unambiguous Synchronization Scheme for GNSS BOC Signals Based on Reconstructed Correlation Function." Sensors 21, no. 6 (March 11, 2021): 1982. http://dx.doi.org/10.3390/s21061982.

Full text

Abstract:

Binary offset carrier (BOC) modulation is a new modulation method that has been gradually applied to the Global Satellite Navigation System (GNSS) in recent years. However, due to the multi-peaks in its auto-correlation function (ACF), it will incur a false lock and generate synchronization ambiguous potentially. In this paper, an unambiguous synchronization method based on a reconstructed correlation function is proposed to solve the ambiguity problem. First, through the shape code vector constructed in this paper, the general cross-correlation function (CCF) expression of the BOC modulated signal will be obtained. Based on the features of the signal correlation function, it is decomposed into a matrix form of trigonometric functions. Then, it generates two local signal waves using a specific method, then the proposed method is implemented to obtain a no-side-peak correlation function by reconstructing the cross-correlation between the received signal and the two local signals. Simulations showed that it fully eliminates the side-peak threat and significantly removes the ambiguity during the synchronization of the BOC signals. This paper also gives the improved structure of acquisition and tracking. The detailed theoretical deduction of detection probability and code tracking error is demonstrated, and the corresponding phase discrimination function is given. In terms of de-blurring ability and detection probability performance, the proposed method outperformed other conventional approaches. The tracking performance was superior to the comparison methods and the phase discrimination curve only had a zero-crossing, which successfully removed the false lock points. In addition, in multipath mitigation, it outperformed the ACF of the BOC signal, and performs as well as the autocorrelation side-peak cancellation technique (ASPeCT) for BOC(kn,n) signals.

APA, Harvard, Vancouver, ISO, and other styles

30

Zhang, Chuan Yi, Chang Wei Mi, and Pei Yang Yao. "Research on Sound Source Localization System Based on Time Delay Estimation." Applied Mechanics and Materials 397-400 (September 2013): 2209–14. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.2209.

Full text

Abstract:

In the estimation of time delay, there always would not appear obvious peak with the basic cross-correlation (CC). In order to solve the problem of the basic cross-correlation method, this essay represents an improved time delay estimation method based on the generalized cross-correlation (GCC) and combines with the microphone array structure to achieve sound source localization. Finally, the simulation results show that this method could measure the sound source’s location accurately with noise and reverberation, and the distance positioning error is less than 10cm, the direction angle error is below 3°.

APA, Harvard, Vancouver, ISO, and other styles

31

Song, J., L. Ma, E. Whitenton, and T. Vorburger. "2D and 3D Surface Texture Comparisons Using Autocorrelation Functions." Key Engineering Materials 295-296 (October 2005): 437–40. http://dx.doi.org/10.4028/www.scientific.net/kem.295-296.437.

Full text

Abstract:

Autocorrelation and cross-correlation functions are proposed for 2D and 3D surface texture comparisons. At the maximum correlation point of the two correlated surface textures, there is a peak shown at the cross-correlation curve. It is proposed to generate a difference function at the maximum correlation point for evaluation of the difference between the two compared surface textures. Based on this method, the National Institute of Standards and Technology (NIST) bullet signature measurement system is developed for the bullet signature measurements of NIST standard bullets.

APA, Harvard, Vancouver, ISO, and other styles

32

Yang, Gang, Wei Dong Li, Yu Tao Wang, and Ming Yu Li. "A Combined Interpolation Method for Cross Correlation Based Particle Velocity Measurement." Advanced Materials Research 508 (April 2012): 67–70. http://dx.doi.org/10.4028/www.scientific.net/amr.508.67.

Full text

Abstract:

Cross correlation techniques have been proved to be a valuable tool for online continuous velocity measurement of particulate solids in pneumatic pipelines. In order to reduce computational complexity the sampling frequency is usually kept as low as possible, and the peak in the correlation function is found by interpolating the correlation function. Parabola functions are commonly used as parametric models of the cross correlation function in time delay estimation. However, the parabolic-fit interpolation method introduces a bias at low sampling rate to the center frequency ratio of input signal. In this paper, a combined interpolation method is proposed to improve the estimation accuracy. Experiments are carried out to evaluate the performance of the proposed interpolation method for low sampling rate. The experimental results have been promising and have shown the potential of the proposed method for particle flow velocity measurements.

APA, Harvard, Vancouver, ISO, and other styles

33

CHOI, SooHwan, and DooSeop EOM. "Minimizing False Peak Errors in Generalized Cross-Correlation Time Delay Estimation Using Subsample Time Delay Estimation." IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96.A, no. 1 (2013): 304–11. http://dx.doi.org/10.1587/transfun.e96.a.304.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Johari, A., B. Vali, and H. Golkarfard. "System reliability analysis of ground response based on peak ground acceleration considering soil layers cross-correlation." Soil Dynamics and Earthquake Engineering 141 (February 2021): 106475. http://dx.doi.org/10.1016/j.soildyn.2020.106475.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Chen, Chulung, and Chih-Sung Wu. "Polychromatic pattern recognition using the non-zero-order joint transform correlator with cross-correlation peak optimization." Journal of Modern Optics 50, no. 9 (June 2003): 1353–64. http://dx.doi.org/10.1080/09500340308235209.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Schoenherr, Désirée, Jane Paulick, Bernhard M. Strauss, Anne-Katharina Deisenhofer, Brian Schwartz, Julian A. Rubel, Wolfgang Lutz, Ulrich Stangier, and Uwe Altmann. "Identification of movement synchrony: Validation of windowed cross-lagged correlation and -regression with peak-picking algorithm." PLOS ONE 14, no. 2 (February 11, 2019): e0211494. http://dx.doi.org/10.1371/journal.pone.0211494.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Huang, Cheng, Ping Yi, Futai Zou, Yao Yao, Wei Wang, and Ting Zhu. "CCID: Cross-Correlation Identity Distinction Method for Detecting Shrew DDoS." Wireless Communications and Mobile Computing 2019 (February 20, 2019): 1–9. http://dx.doi.org/10.1155/2019/6705347.

Full text

Abstract:

This study presents a new method for detecting Shrew DDoS (Distributed Denial of Service) attacks and analyzes the characteristics of the Shrew DDoS attack. Shrew DDoS is periodic to be suitable for the server’s TCP (Transmission Control Protocol) timer. It has lower maximum to bypass peak detection. This periodicity makes it distinguishable from normal data packets. By proposing the CCID (Cross-Correlation Identity Distinction) method to distinguish the flow properties, it quantifies the difference between a normal flow and an attack flow. Simultaneously, we calculated the cross-correlation between the attack flow and the normal flow in three different situations. The server can use its own TCP flow timer to construct a periodic attack flow. The cross-correlation between Gaussian white noise and simulated attack flow is less than 0.3. The cross-correlation between single-door function and simulated attack flow is 0.28. The cross-correlation between actual attack flow and simulated attack flow is more than 0.8. This shows that we can quantitatively distinguish the attack effects of different signals. By testing 4 million data, we can prove that it has a certain effect in practice.

APA, Harvard, Vancouver, ISO, and other styles

38

Qian, Yi Xian, Li Bao Yang, Xiao Wei Cheng, and Xue Ting Hong. "Improved Method of Target Detection on Optoelectronic Hybrid Joint Transform Correlator in Cluttered Scences." Applied Mechanics and Materials 130-134 (October 2011): 4041–44. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.4041.

Full text

Abstract:

A classical joint transform correlator (JTC) usually yields large correlation sidelobes as well as a large correlation peak width, strong zero-order peak, and low diffraction efficiency, which make the detection ability of JTC lower. To overcome these difficulties, firstly, a joint power spectrum (JPS) subtraction technique in Fourier plane was proposed, where reference image power spectrum and object image power spectrum are subtracted from the JPS before inverse Fourier-transform operation, it is obvious that the modified JPS removes the zero-order term. Secondly, a fringe-adjusted filter (FAF) was presented to suppress sidelobes and noises. The modified JPS is multiplied by a FAF before the inverse Fourier-transform operation to obtain the cross-correlation peak. Computer simulations demonstrated the improved method can obviously remove zero-order diffraction and effectively suppress the sidelobes and noises compared with classic JTC, and then improve the detection ability for JTC. Experimental results presented the sharp correlation peak and also confirmed the method effectiveness.

APA, Harvard, Vancouver, ISO, and other styles

39

Buchanan, James T., and Stefan Kasicki. "Segmental Distribution of Common Synaptic Inputs to Spinal Motoneurons During Fictive Swimming in the Lamprey." Journal of Neurophysiology 82, no. 3 (September 1, 1999): 1156–63. http://dx.doi.org/10.1152/jn.1999.82.3.1156.

Full text

Abstract:

These experiments were designed to measure the degree of shared synaptic inputs coming to pairs of myotomal motoneurons during swimming activity in the isolated spinal cord of the lamprey. In addition, the experiments measured the decrease in the degree of shared synaptic inputs with the distance between the motoneurons to assess the segmental distribution of these shared inputs. Intracellular microelectrode recordings of membrane potential were made simultaneously on pairs of myotomal motoneurons during swimming activity induced with an excitatory amino acid. The swim cycle oscillations of motoneuron membrane potentials were removed with a digital notch filter, thus leaving the fast synaptic activities that underlie these slower oscillations. Cross-correlations of the fast synaptic activities in two simultaneously recorded motoneurons were made to measure the degree of shared inputs. The cross-correlation was done on time windows restricted to one swim cycle or to part of a swim cycle, and 50 consecutive swim cycle cross-correlograms then were averaged. The peak coefficients of the cross-correlations exhibited a wide range, even for pairs of motoneurons located near one another (range = 0.06–0.74, for pairs located within 2 segments). This observation suggests that there may be different functional classes of myotomal motoneurons with inputs originating from different sets of premotor interneurons. In spite of this variability, the mean peak correlation coefficients of motoneuron pairs clearly decreased with the distance between them. With separations of more than five segments, there was little or no clear correlation between the motoneurons (range = 0.04–0.10). These results suggest that common synaptic inputs to motoneurons during fictive swimming originate from local premotor interneurons and that beyond five spinal segments, common premotor inputs are rare or weak to motoneurons. Thus the premotor signals originating from the locomotor network have relatively short distribution lengths, on the order of 5 segments of 120 total spinal segments.

APA, Harvard, Vancouver, ISO, and other styles

40

Pauluis, Quentin. "Statistical Signs of Common Inhibitory Feedback with Delay." Neural Computation 12, no. 11 (November 1, 2000): 2513–18. http://dx.doi.org/10.1162/089976600300014818.

Full text

Abstract:

Cross-correlation histograms (CCHs) sometimes exhibit an isolated central peak flanked by two troughs. What can cause this pattern? The absence of CCH satellite peak makes an oscillatory common input doubtful. It is here shown using a simple counting model that a common inhibitory feedback with delay can account for this pattern.

APA, Harvard, Vancouver, ISO, and other styles

41

Colder, B. W., C. L. Wilson, R. C. Frysinger, L. C. Chao, R. M. Harper, and J. Engel. "Neuronal synchrony in relation to burst discharge in epileptic human temporal lobes." Journal of Neurophysiology 75, no. 6 (June 1, 1996): 2496–508. http://dx.doi.org/10.1152/jn.1996.75.6.2496.

Full text

Abstract:

1. Synchronous interactions between neurons in mesial temporal structures of patients with complex partial seizures were studied using cross-correlation analyses. We recorded spontaneous activity from 293 neurons in 24 patients during the interictal state. Patients had depth microelectrodes chronically implanted in amygdala, hippocampal formation, and parahippocampal gyrus to record epileptic activity. One hundred twenty-five cells were recorded from the temporal lobe commonly initiating seizures (ipsilateral temporal lobe), and 168 cells from the contralateral temporal lobe. Eight hundred forty-three cross-correlograms were constructed between all pairs of simultaneously recorded neurons. Cross-correlogram peaks or troughs that exceeded confidence limits within 200 ms of the origin were considered evidence of synchronous neuronal interaction. 2. Synchronous neuronal interactions were observed in 223 of 843 cross-correlograms. Eighty-six percent of these 223 cross-correlograms showed significant central peaks (peak interactions), suggesting excitatory interactions, whereas the remainder displayed significant central troughs (trough interactions), suggesting inhibitory interactions. 3. Cross-correlograms constructed using cells from the ipsilateral temporal lobe (ipsilateral cross-correlograms) were more likely to display significant central troughs (14/262) than cross-correlograms constructed using cells from the contralateral temporal lobe (6/376; contralateral cross-correlograms). Similarly, cross-correlograms constructed using one cell from each hemisphere (11/205; bilateral cross-correlograms) were also more likely to display significant central troughs (trough interactions) than contralateral cross-correlograms. Both ipsilateral (77/262) and contralateral cross-correlograms (102/376) were more likely to display significant central peaks (peak interactions) than bilateral cross-correlograms (13/205). 4. Cells from different structures in the ipsilateral temporal lobe were more likely to display significant trough interactions (10/ 114) than neurons in different contralateral structures. We also compared the proportion of significant peak interactions between cells within the ipsilateral and contralateral sides of each structure. Neurons in the contralateral entorhinal cortex were more likely to show peak interactions (21/55) than cells from the ipsilateral entorhinal cortex (3/31). Also, cells in the ipsilateral presubiculum showed a higher proportion of peak interactions (9/16) than their contralateral homologues (5/30). 5. Neuronal burst discharges were defined as three or more action potentials (or spikes) separated by interspike intervals of < or = 30 ms, or two spikes separated by an interval of < or = 15 ms. The contribution of burst discharge to synchronous peak interaction was compared between temporal lobes. Cells used to construct ipsilateral cross-correlograms displaying significant central peaks (n = 154) were found to have significantly reduced burst discharge contributions to the observed synchronous peaks in comparison with their contralateral homologues (n = 204). When cross-correlograms were separated by regions, burst discharge contributions to synchronous peak interactions between cells in the ipsilateral hippocampus (n = 72) were significantly smaller than the contributions from cells in the contralateral hippocampus (n = 44). 6. The results suggest that in the interictal state, synchronous neuronal burst discharge is not a distinguishing feature of epileptogenic regions of patients with complex partial seizures, but inhibitory neuronal interactions are increased in regions of seizure initiation. Increases in the strength and spread of local inhibition in seizure initiating regions in these patients may result in a greater proportion of inhibitory interactions and could also cause increased synchrony between isolated action potentials.(ABSTRACT TRUNCATED)

APA, Harvard, Vancouver, ISO, and other styles

42

Xie, Junfeng, Fan Mo, Chao Yang, Pin Li, and Shiqiang Tian. "A NOVEL SUB-PIXEL MATCHING ALGORITHM BASED ON PHASE CORRELATION USING PEAK CALCULATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 3, 2016): 253–57. http://dx.doi.org/10.5194/isprsarchives-xli-b1-253-2016.

Full text

Abstract:

The matching accuracy of homonymy points of stereo images is a key point in the development of photogrammetry, which influences the geometrical accuracy of the image products. This paper presents a novel sub-pixel matching method phase correlation using peak calculation to improve the matching accuracy. The peak theoretic centre that means to sub-pixel deviation can be acquired by Peak Calculation (PC) according to inherent geometrical relationship, which is generated by inverse normalized cross-power spectrum, and the mismatching points are rejected by two strategies: window constraint, which is designed by matching window and geometric constraint, and correlation coefficient, which is effective for satellite images used for mismatching points removing. After above, a lot of high-precise homonymy points can be left. Lastly, three experiments are taken to verify the accuracy and efficiency of the presented method. Excellent results show that the presented method is better than traditional phase correlation matching methods based on surface fitting in these aspects of accuracy and efficiency, and the accuracy of the proposed phase correlation matching algorithm can reach 0.1 pixel with a higher calculation efficiency.

APA, Harvard, Vancouver, ISO, and other styles

43

Xie, Junfeng, Fan Mo, Chao Yang, Pin Li, and Shiqiang Tian. "A NOVEL SUB-PIXEL MATCHING ALGORITHM BASED ON PHASE CORRELATION USING PEAK CALCULATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 3, 2016): 253–57. http://dx.doi.org/10.5194/isprs-archives-xli-b1-253-2016.

Full text

Abstract:

The matching accuracy of homonymy points of stereo images is a key point in the development of photogrammetry, which influences the geometrical accuracy of the image products. This paper presents a novel sub-pixel matching method phase correlation using peak calculation to improve the matching accuracy. The peak theoretic centre that means to sub-pixel deviation can be acquired by Peak Calculation (PC) according to inherent geometrical relationship, which is generated by inverse normalized cross-power spectrum, and the mismatching points are rejected by two strategies: window constraint, which is designed by matching window and geometric constraint, and correlation coefficient, which is effective for satellite images used for mismatching points removing. After above, a lot of high-precise homonymy points can be left. Lastly, three experiments are taken to verify the accuracy and efficiency of the presented method. Excellent results show that the presented method is better than traditional phase correlation matching methods based on surface fitting in these aspects of accuracy and efficiency, and the accuracy of the proposed phase correlation matching algorithm can reach 0.1 pixel with a higher calculation efficiency.

APA, Harvard, Vancouver, ISO, and other styles

44

Garg, Vinayak, Akariti Sharma, and R. K. Moudgil. "Finite-T correlations and free exchange-correlation energy of quasi-one-dimensional electron gas." Modern Physics Letters B 32, no. 05 (February 20, 2018): 1850060. http://dx.doi.org/10.1142/s0217984918500604.

Full text

Abstract:

We have studied the effect of temperature on static density–density correlations and plasmon excitation spectrum of quasi-one-dimensional electron gas (Q1DEG) using the random phase approximation (RPA). Numerical results for static structure factor, pair-correlation function, static density susceptibility, free exchange-correlation energy and plasmon dispersion are presented over a wide range of temperature and electron density. As an interesting result, we find that the short-range correlations exhibit a non-monotonic dependence on temperature T, initially growing stronger (i.e. the pair-correlation function at small inter-electron spacing assuming relatively smaller values) with increasing T and then weakening above a critical T. The cross-over temperature is found to increase with increasing coupling among electrons. Also, the [Formula: see text] peak in the static density susceptibility [Formula: see text] at T = 0 K smears out with rising T. The free exchange-correlation energy and plasmon dispersion show a significant variation with T, and the trend is qualitatively the same as in higher dimensions.

APA, Harvard, Vancouver, ISO, and other styles

45

Moritz, Chet T., Evangelos A. Christou, François G. Meyer, and Roger M. Enoka. "Coherence at 16-32 Hz Can Be Caused by Short-Term Synchrony of Motor Units." Journal of Neurophysiology 94, no. 1 (July 2005): 105–18. http://dx.doi.org/10.1152/jn.01179.2004.

Full text

Abstract:

Time- and frequency-domain measures of discharge times for pairs of motor units are used to infer the proportion of common synaptic input received by motor neurons. The physiological mechanisms that can produce the experimentally observed peaks in the cross-correlation histogram and the coherence spectrum are uncertain. The present study used a computational model to impose synchronization on the discharge times of motor units. Randomly selected discharge times of a unit that was being synchronized to a reference unit were aligned with some of the discharge times of the reference unit, provided the original discharge time was within 30 ms of the discharge by the reference unit. All time-domain measures (indexes CIS, E, and k′) were sensitive to changes in the level of imposed motor-unit synchronization ( P < 0.01). In addition, synchronization caused a peak between 16 and 32 Hz in the coherence spectrum. The shape of the cross-correlogram determined the frequency at which the peak occurred in the coherence spectrum. Further, the magnitude of the coherence peak was highly correlated with the time-domain measures of motor-unit synchronization ( r2 > 0.80), with the highest correlation occurring for index E ( r2 = 0.98). Thus the peak in the 16- to 32-Hz band of the coherence spectrum can be caused by the time that individual discharges are advanced or delayed to produce synchrony. Although the in vivo processes that adjust the timing of motor-unit discharges are not fully understood, these results suggest that they may not depend entirely on an oscillatory drive by the CNS.

APA, Harvard, Vancouver, ISO, and other styles

46

Spiesberger, John L. "Finding the right cross‐correlation peak for locating sounds in multipath environments with a fourth‐moment function." Journal of the Acoustical Society of America 109, no. 5 (May 2001): 2298. http://dx.doi.org/10.1121/1.4744060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Spiesberger, John L. "Finding the right cross-correlation peak for locating sounds in multipath environments with a fourth-moment function." Journal of the Acoustical Society of America 108, no. 3 (2000): 1349. http://dx.doi.org/10.1121/1.1287709.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

JIA, ZHENG-LIN, and DONG-CHENG MEI. "THE CRITICAL EFFECTS OF TIME DELAY AND NOISE CORRELATION ON STOCHASTIC RESONANCE IN AN ASYMMETRIC BISTABLE SYSTEM." Modern Physics Letters B 25, no. 16 (June 30, 2011): 1377–91. http://dx.doi.org/10.1142/s0217984911026310.

Full text

Abstract:

We investigate the effects of time delay and noise correlation on the stochastic resonance induced by a multiplicative signal in an asymmetric bistable system. By the two-state theory and small delay approximation, the expression of the output signal-to-noise ratio (SNR) is obtained in the adiabatic limit. The results show that SNR as a function of the multiplicative noise intensity D shows a transition from two peaks to one peak with the decreasing of cross-correlation strength λ and the increasing of delay time τ. Moreover, there are the doubly critical phenomena for SNR versus λ and τ, and SNR versus D and α (additive noise intensity).

APA, Harvard, Vancouver, ISO, and other styles

49

Colavincenzo, Manuel, Xiuhui Tan, Simone Ammazzalorso, Stefano Camera, Marco Regis, Jun-Qing Xia, and Nicolao Fornengo. "Searching for gamma-ray emission from galaxy clusters at low redshift." Monthly Notices of the Royal Astronomical Society 491, no. 3 (November 22, 2019): 3225–44. http://dx.doi.org/10.1093/mnras/stz3263.

Full text

Abstract:

ABSTRACT We report the identification of a positive cross-correlation signal between the unresolved gamma-ray emission, measured by the Fermi Large Area Telescope, and four different galaxy cluster catalogues. The selected catalogues peak at low-redshift and span different frequency bands, including infrared, optical, and X-rays. The signal-to-noise ratio of the detected cross-correlation amounts to 3.5 in the most significant case. We investigate and comment about its possible origin, in terms of compact gamma-ray emission from AGNs inside clusters or diffuse emission from the intracluster medium. The analysis has been performed by introducing an accurate estimation of the cross-correlation power-spectrum covariance matrix, built with mock realizations of the gamma and galaxy cluster maps. Different methods to produce the mock realizations starting from the data maps have been investigated and compared, identifying suitable techniques which can be generalized to other cross-correlation studies.

APA, Harvard, Vancouver, ISO, and other styles

50

Salisbury, Dereck L., and Fang Yu. "RELATIONSHIP OF CARDIOPULMONARY EXERCISE TESTING AND FIELD WALKING TESTS IN MILD-MODERATE ALZHEIMER’S DEMENTIA." Innovation in Aging 3, Supplement_1 (November 2019): S611. http://dx.doi.org/10.1093/geroni/igz038.2275.

Full text

Abstract:

Abstract The purpose of this study was to investigate relationships among peak exercise parameters on 6-minute walk (6MWT) and shuttle walk tests (SWT), and laboratory-based cardiopulmonary exercise testing (CPET). These relationships have been established in cardiopulmonary patient populations, but not in community-dwelling older adults with mild-moderate Alzheimer’s dementia (AD). This study is a cross-sectional analysis of the baseline data of 6MWT, SWT, and CPET from the FIT-AD Trial (n=88: 49 males [76.6 {7.0} years and MMSE 21.5{3.5}] and 39 females [77.3 {6.5} years and MMSE 22.1 {3.4}]). Peak values for each test included heart rate (HR), systolic blood pressure (SBP), and rating of perceived exertion (RPE). Peak oxygen assumption (VO2) was measured in the CPET. Peak walking distance (PWD) was measured for the 6MWT and SWT. CPET produced significantly higher peak HR (118.7 [17.5] vs. 106 [22.8] vs. 106 [18.8] bpm), RPE (16 [2.1] vs. 12 [2.3] vs. 11 [2.1]) and SBP (182 [23.7] vs. 156 [18.9] vs. 150 [16.9] mmHg) compared to the SWT and 6MWT respectively. PWD on SWT (240.4 [128.1] m) and 6MWT (364.3 [108.5] m) significantly correlated with peak VO2 (17.0 [4.3]ml/kg/min) on CPET (r=.44 and r=.43) respectively. Correlations of peak VO2 and PWD on SWT in persons with AD are considerably lower than what is seen for persons with cardiopulmonary diseases. This lower correlation seen in our sample may be due to shorter PWD on walking tests. Future research should focus how mobility affects correlation of peak values on these tests.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Cross Correlation Peak'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles