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1
Jung, Jungkyo, and Sang-Ho Yun. "Evaluation of Coherent and Incoherent Landslide Detection Methods Based on Synthetic Aperture Radar for Rapid Response: A Case Study for the 2018 Hokkaido Landslides." Remote Sensing 12, no. 2 (January 13, 2020): 265. http://dx.doi.org/10.3390/rs12020265.
Повний текст джерелаАнотація:
Damage mapping using Synthetic Aperture Radar (SAR) imagery has been studied in recent decades to support rapid response to natural disasters. Many researches have been developing coherent and incoherent change detection. However, their performances can vary depending on the types of the damages, the characteristics of the scatterers and the corresponding capability of algorithms. In particular, the coherence-based methods have been used as promising detectors over urban areas where high coherences are observed, but their detection accuracies still remain controversial over the area where low coherences are mainly observed such as the 2018 Hokkaido landslides. In order to understand the characteristics of landslide (damage) detectors for low-coherence areas and find an alternative and complementary method, we designed the coherence difference, coherence normalized difference, log-ratio, intensity correlation difference, and normalized differences of the intensity correlation assuming limited availability of dataset, and also developed multi-temporal algorithms using the coherence, intensity, and intensity correlation. They were tested and evaluated using multiple polygons extracted from aerial photos. We were able to observe that the multi-temporal intensity correlation method has the potential to detect the landslides over the low coherence region and all types of land uses.
2
Arce-McShane, Fritzie I., Callum F. Ross, Kazutaka Takahashi, Barry J. Sessle, and Nicholas G. Hatsopoulos. "Primary motor and sensory cortical areas communicate via spatiotemporally coordinated networks at multiple frequencies." Proceedings of the National Academy of Sciences 113, no. 18 (April 18, 2016): 5083–88. http://dx.doi.org/10.1073/pnas.1600788113.
Повний текст джерелаАнотація:
Skilled movements rely on sensory information to shape optimal motor responses, for which the sensory and motor cortical areas are critical. How these areas interact to mediate sensorimotor integration is largely unknown. Here, we measure intercortical coherence between the orofacial motor (MIo) and somatosensory (SIo) areas of cortex as monkeys learn to generate tongue-protrusive force. We report that coherence between MIo and SIo is reciprocal and that neuroplastic changes in coherence gradually emerge over a few days. These functional networks of coherent spiking and local field potentials exhibit frequency-specific spatiotemporal properties. During force generation, theta coherence (2–6 Hz) is prominent and exhibited by numerous paired signals; before or after force generation, coherence is evident in alpha (6–13 Hz), beta (15–30 Hz), and gamma (30–50 Hz) bands, but the functional networks are smaller and weaker. Unlike coherence in the higher frequency bands, the distribution of the phase at peak theta coherence is bimodal with peaks near 0° and ±180°, suggesting that communication between somatosensory and motor areas is coordinated temporally by the phase of theta coherence. Time-sensitive sensorimotor integration and plasticity may rely on coherence of local and large-scale functional networks for cortical processes to operate at multiple temporal and spatial scales.
3
CAREY, WILLIAM M., JAMES F. LYNCH, WILLIAM L. SIEGMANN, ILYA ROZENFELD, and BRIAN J. SPERRY. "SOUND TRANSMISSION AND SPATIAL COHERENCE IN SELECTED SHALLOW-WATER AREAS: MEASUREMENTS AND THEORY." Journal of Computational Acoustics 14, no. 02 (June 2006): 265–98. http://dx.doi.org/10.1142/s0218396x06003037.
Повний текст джерелаАнотація:
Experiments from several shallow-water areas are summarized. Coherent sound transmission results, particularly wavenumber spectra, are compared to range-dependent calculations that use oceanographic and geophysical characteristics from measurements and archives as bounded inputs to the propagation codes. In general excellent agreement was obtained between the measured and calculated results for both narrowband and broadband transmissions between 50 Hz and 1 kHz to ranges of 40 km. A relative signal gain (RSG) method for the estimation of horizontal coherence length was applied to measured RSG results and yielded coherence lengths on the order of 30λ at 400 Hz at distances of 40 km. Perturbation theory was applied to the shallow-water waveguide under the condition of adiabatic normal modes and expressions were derived for the phase structure function that was simplified by the use of Gaussian correlation functions. These analytical results, along with estimates of the variances of the environmental variables permitted the estimation of the coherence function and the RSG. The calculated coherence function and RSG were found to be consistent with measured RSG and replica correlation results. The fluctuations in the oceanic water volume were found to be the dominant factor in the loss of coherence.
4
Cheung, Mei-chun, Agnes S. Chan, Yvonne M. Han, and Sophia L. Sze. "Brain Activity During Resting State in Relation to Academic Performance." Journal of Psychophysiology 28, no. 2 (April 1, 2014): 47–53. http://dx.doi.org/10.1027/0269-8803/a000107.
Повний текст джерелаАнотація:
EEG coherence has been widely used to investigate brain activity and learning. However, relatively little is known about the relationship between resting-state EEG coherence and academic performance. The present study investigated this relationship with 140 healthy, normal participants. EEG was recorded during resting periods, with eyes open for 3 min, and the recordings were analyzed for 64 electrode positions in the theta (4–8 Hz), alpha (8–12 Hz), and beta (12–25 Hz) frequency bands. Coherence, defined as the spectral cross-correlation between two signals normalized by their power spectra, was calculated. Short- and long-range intrahemispheric coherence within each hemisphere and interhemispheric coherence across the left and right hemispheres were then computed and compared for each of the theta, alpha, and beta bands. The results showed that academic performance, as measured by grade point average (GPA), was negatively correlated with short-range intrahemispheric alpha and beta coherences in both hemispheres and with interhemispheric alpha and beta coherences in the temporal cortical regions. Therefore, better academic performers demonstrated more decoupling of brain areas when resting with eyes open. This is consistent with a model that relates decreased coherence to neural efficiency.
5
MORIN, JEAN-FRÉDÉRIC, and AMANDINE ORSINI. "Policy coherency and regime complexes: the case of genetic resources." Review of International Studies 40, no. 2 (June 17, 2013): 303–24. http://dx.doi.org/10.1017/s0260210513000168.
Повний текст джерелаАнотація:
AbstractThis study argues that ‘regime complexes’ and ‘policy coherence’ are two faces of the same integrative process. The development of regime complexes co-evolves with the pressures on decision makers to coordinate their policies in various issue-areas. Conceptually, we introduce a typology of policy coherency (erratic, strategic, functionalistic, and systemic) according to its procedural and substantive components. Empirically, by triangulating quantitative and qualitative data, we use this typology for the case of the genetic resources' regime complex to illustrate the links between regime complexes and policy coherency. Our results suggest that a coherent policymaking process favours integrated regime complexes, while greater exposure to a regime complex increases the pressure to have a coherent policymaking. This study fills a gap in the literature on regime complexes by providing a micro-macro model linking structure to agency.
6
Zhang, Yue, Kun Fu, Xian Sun, Guangluan Xu, and Hongqi Wang. "MODEL ACCURACY COMPARISON FOR HIGH RESOLUTION INSAR COHERENCE STATISTICS OVER URBAN AREAS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 21, 2016): 753–56. http://dx.doi.org/10.5194/isprsarchives-xli-b7-753-2016.
Повний текст джерелаАнотація:
The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR) images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR) coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.
7
Zhang, Yue, Kun Fu, Xian Sun, Guangluan Xu, and Hongqi Wang. "MODEL ACCURACY COMPARISON FOR HIGH RESOLUTION INSAR COHERENCE STATISTICS OVER URBAN AREAS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (June 21, 2016): 753–56. http://dx.doi.org/10.5194/isprs-archives-xli-b7-753-2016.
Повний текст джерелаАнотація:
The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR) images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR) coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.
8
Kocur-Bera, Katarzyna, and Hubert Frąszczak. "Coherence of Cadastral Data in Land Management—A Case Study of Rural Areas in Poland." Land 10, no. 4 (April 10, 2021): 399. http://dx.doi.org/10.3390/land10040399.
Повний текст джерелаАнотація:
The cadaster functions laid down in the law should guarantee the safety of one’s rights. The reliability of the data gathered in the cadaster affects decisions concerning specific real estate or taken within the sphere of economic management. The legislation often requires the use of cadastral data, which makes it necessary to keep it up-to-date and coherent with the situation in the field. The effects of a lack of coherence may impact public finances and land management. Maintaining high-quality cadastral data is time-consuming and expensive. This study analysed the data coherence between the state in the field and cadastral documents. The analysis was based mainly on the information about the area of a plot and land use. The coherence index showed that the differences between registers and the state in the field range from 30% to 80%. This can be changed by comprehensive data modernisation, which can be facilitated using modern technology. Given the diverse use of cadastral data and the global trends in cadaster development and implementation of the third dimension, the currency and reliability of cadastral data become particularly important.
9
Wang, Ziwei, Chao Wang, Hong Zhang, and Fan Wu. "‘Scatter coherence’ suppression for TomoSAR in urban areas." Remote Sensing Letters 6, no. 11 (September 14, 2015): 894–903. http://dx.doi.org/10.1080/2150704x.2015.1088670.
Повний текст джерела
10
Olen, Stephanie, and Bodo Bookhagen. "Mapping Damage-Affected Areas after Natural Hazard Events Using Sentinel-1 Coherence Time Series." Remote Sensing 10, no. 8 (August 13, 2018): 1272. http://dx.doi.org/10.3390/rs10081272.
Повний текст джерелаАнотація:
The emergence of the Sentinel-1A and 1B satellites now offers freely available and widely accessible Synthetic Aperture Radar (SAR) data. Near-global coverage and rapid repeat time (6–12 days) gives Sentinel-1 data the potential to be widely used for monitoring the Earth’s surface. Subtle land-cover and land surface changes can affect the phase and amplitude of the C-band SAR signal, and thus the coherence between two images collected before and after such changes. Analysis of SAR coherence therefore serves as a rapidly deployable and powerful tool to track both seasonal changes and rapid surface disturbances following natural disasters. An advantage of using Sentinel-1 C-band radar data is the ability to easily construct time series of coherence for a region of interest at low cost. In this paper, we propose a new method for Potentially Affected Area (PAA) detection following a natural hazard event. Based on the coherence time series, the proposed method (1) determines the natural variability of coherence within each pixel in the region of interest, accounting for factors such as seasonality and the inherent noise of variable surfaces; and (2) compares pixel-by-pixel syn-event coherence to temporal coherence distributions to determine where statistically significant coherence loss has occurred. The user can determine to what degree the syn-event coherence value (e.g., 1st, 5th percentile of pre-event distribution) constitutes a PAA, and integrate pertinent regional data, such as population density, to rank and prioritise PAAs. We apply the method to two case studies, Sarpol-e, Iran following the 2017 Iran-Iraq earthquake, and a landslide-prone region of NW Argentina, to demonstrate how rapid identification and interpretation of potentially affected areas can be performed shortly following a natural hazard event.
11
Washaya, P., and T. Balz. "SAR COHERENCE CHANGE DETECTION OF URBAN AREAS AFFECTED BY DISASTERS USING SENTINEL-1 IMAGERY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (April 30, 2018): 1857–61. http://dx.doi.org/10.5194/isprs-archives-xlii-3-1857-2018.
Повний текст джерелаАнотація:
The study focuses on two study areas: San Juan in Puerto Rico, which was affected by Hurricane Maria in September 2017, and Sarpol Zahab in Iran, which was one of the towns affected by an earthquake in November 2017. In our study, we generate coherence images, and classify them into areas of ‘change’ and ‘no-change’. A statistical analysis is made by converting the coherence results into point data, creating street blocks for the study areas and integrating the point data into the street blocks to calculate the standard deviation over the whole stack of images. Additionally, Landsat imagery is used to create land-use classes, convert them to polygons and integrate the polygon classes to the coherence maps to determine the average coherence loss per class for each disaster. Results show 65 % loss in coherence after the earthquake in Sarpol-e-Zahab and 75 % loss in Puerto Rico after the Hurricane. Land-use classes show coherence losses to below 0.5 for each disaster.
12
Washaya, Prosper, Timo Balz, and Bahaa Mohamadi. "Coherence Change-Detection with Sentinel-1 for Natural and Anthropogenic Disaster Monitoring in Urban Areas." Remote Sensing 10, no. 7 (June 28, 2018): 1026. http://dx.doi.org/10.3390/rs10071026.
Повний текст джерелаАнотація:
Rapid, reliable, and continuous information is an essential component in disaster monitoring and management. Remote sensing data could be a solution, but often cannot provide continuous data due to an absence of global coverage and weather and daylight dependency. To overcome these challenges, this study makes use of weather and day/light independent Sentinel-1 data with a global coverage to monitor localized effects of different types of disasters using the Coherence Change-Detection (CCD) technique. Coherence maps were generated from Synthetic Aperture Radar (SAR) images and used to classify areas of change and no change in six study areas. These sites are located in Syria, Puerto Rico, California, and Iran. The study areas were divided into street blocks, and the standard deviation was calculated for the coherence images for each street block over entire image stacks. The study areas were classified by land-use type to reveal the spatial variation in coherence loss after a disaster. While temporal decorrelation exhibits a general loss in coherence over time, disaster occurrence, however, indicates a significant loss in coherence after an event. The variations of each street block from the average coherence for the entire image stack, as measured by a high standard deviation after a particular disaster, is an indication of disaster induced building damage.
13
O'Connor, Sean M., Rune W. Berg, and David Kleinfeld. "Coherent Electrical Activity Between Vibrissa Sensory Areas of Cerebellum and Neocortex Is Enhanced During Free Whisking." Journal of Neurophysiology 87, no. 4 (April 1, 2002): 2137–48. http://dx.doi.org/10.1152/jn.00229.2001.
Повний текст джерелаАнотація:
We tested if coherent signaling between the sensory vibrissa areas of cerebellum and neocortex in rats was enhanced as they whisked in air. Whisking was accompanied by 5- to 15-Hz oscillations in the mystatial electromyogram, a measure of vibrissa position, and by 5- to 20-Hz oscillations in the differentially recorded local field potential (∇LFP) within the vibrissa area of cerebellum and within the ∇LFP of primary sensory cortex. We observed that only 10% of the activity in either cerebellum or sensory neocortex was significantly phase-locked to rhythmic motion of the vibrissae; the extent of this modulation is in agreement with the results from previous single-unit measurements in sensory neocortex. In addition, we found that 40% of the activity in the vibrissa areas of cerebellum and neocortex was significantly coherent during periods of whisking. The relatively high level of coherence between these two brain areas, in comparison with their relatively low coherence with whisking per se, implies that the vibrissa areas of cerebellum and neocortex communicate in a manner that is incommensurate with whisking. To the extent that the vibrissa areas of cerebellum and neocortex communicate over the same frequency band as that used by whisking, these areas must multiplex electrical activity that is internal to the brain with activity that is that phase-locked to vibrissa sensory input.
14
Meier, Kimberly, Marita Partanen, and Deborah Giaschi. "Neural Correlates of Speed-Tuned Motion Perception in Healthy Adults." Perception 47, no. 6 (April 23, 2018): 660–83. http://dx.doi.org/10.1177/0301006618771463.
Повний текст джерелаАнотація:
It has been suggested that slow and medium-to-fast speeds of motion may be processed by at least partially separate mechanisms. The purpose of this study was to establish the cortical areas activated during motion-defined form and global motion tasks as a function of speed, using functional magnetic resonance imaging. Participants performed discrimination tasks with random dot stimuli at high coherence, at coherence near their own thresholds, and for random motion. Stimuli were moving at 0.1 or 5 deg/s. In the motion-defined form task, lateral occipital complex, V5/MT+ and intraparietal sulcus showed greater activation by high or near-threshold coherence than by random motion stimuli; V5/MT+ and intraparietal sulcus demonstrated greater activation for 5 than 0.1 deg/s dot motion. In the global motion task, only high coherence stimuli elicited significant activation over random motion; this activation was primarily in nonclassical motion areas. V5/MT+ was active for all motion conditions and showed similar activation for coherent and random motion. No regions demonstrated speed-tuning effects for global motion. These results suggest that similar cortical systems are activated by slow- and medium-speed stimuli during these tasks in healthy adults.
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Yaqoob, Zahid, Jigang Wu, Emily J. McDowell, Xin Heng, and Changhuei Yang. "Methods and application areas of endoscopic optical coherence tomography." Journal of Biomedical Optics 11, no. 6 (2006): 063001. http://dx.doi.org/10.1117/1.2400214.
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Kim, Yujin, Jihwan Woo, and Minjung Woo. "Effects of Stress and Task Difficulty on Working Memory and Cortical Networking." Perceptual and Motor Skills 124, no. 6 (September 24, 2017): 1194–210. http://dx.doi.org/10.1177/0031512517732851.
Повний текст джерелаАнотація:
This study investigated interactive effects of stress and task difficulty on working memory and cortico-cortical communication during memory encoding. Thirty-eight adolescent participants (mean age of 15.7 ± 1.5 years) completed easy and hard working memory tasks under low- and high-stress conditions. We analyzed the accuracy and reaction time (RT) of working memory performance and inter- and intrahemispheric electroencephalogram coherences during memory encoding. Working memory accuracy was higher, and RT shorter, in the easy versus the hard task. RT was shorter under the high-stress (TENS) versus low-stress (no-TENS) condition, while there was no difference in memory accuracy between the two stress conditions. For electroencephalogram coherence, we found higher interhemispheric coherence in all bands but only at frontal electrode sites in the easy versus the hard task. On the other hand, intrahemispheric coherence was higher in the left hemisphere in the easy (versus hard task) and higher in the right hemisphere (with one exception) in the hard (versus easy task). Inter- and intracoherences were higher in the low- versus high-stress condition. Significant interactions between task difficulty and stress condition were observed in coherences of the beta frequency band. The difference in coherence between low- and high-stress conditions was greater in the hard compared with the easy task, with lower coherence under the high-stress condition relative to the low-stress condition. Stress seemed to cause a decrease in cortical network communications between memory-relevant cortical areas as task difficulty increased.
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Gonnuru, P., S. Kumar, and A. S. Kumar. "PSINSAR COHERENCE BASED DISPLACEMENT ANALYSIS OF KRISHNA DELTA USING SENTINEL-1 INTERFEROMETRIC WIDE SWATH DATA." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-5 (November 15, 2018): 273–78. http://dx.doi.org/10.5194/isprs-annals-iv-5-273-2018.
Повний текст джерелаАнотація:
<p><strong>Abstract.</strong> The problem of decorrelation leading to loss of coherence has been a major source of concern to identify the various problems of erosion and deposition in delta. In this study, Permanent Scatter Interferometric SAR (PsInSAR) technique was used to identify the Permanent Scatter Candidates (PSCs) to explore its potential in identifying displacement based on coherence of various features in delta during the dry and wet periods. PSCs are coherent over interferograms acquired during different time periods. The study was conducted using Sentinel-1 C-band Interferometric Wide (IW) swath datasets acquired from 25<sup>th</sup> October 2016 to 10<sup>th</sup> June 2017 over Krishna Delta. The datasets were deramped and stitched prior to co-registering the master and slave images. Interferograms were generated, phase unwrapped and filtered after which the PSCs were identified based on Amplitude Stability index. The problem of tropospheric phase delay causing decorrelation was removed based on the difference in the phase residual of the connected PSCs. Ps coherence map was generated showing coherence as low as 0.28 to 0.38 in mangroves due to volume decorrelation and 0.5 to 0.85 in village areas. A prominent feature, vernal pool exhibited high variation in coherence (0.28 to 0.45) depending on monsoon or summer season. An integrated cumulative displacement map was generated indicating the areas where erosion and deposition has taken place and these depositional values of certain deltaic features were in conjunction with coherence.</p>
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Yang, Bo, Huaping Xu, Liming Jiang, Ronggang Huang, Zhiwei Zhou, Hansheng Wang, and Wei Liu. "A Multicomponent Temporal Coherence Model for 3-D Phase Unwrapping in Time-Series InSAR of Seasonal Deformation Areas." Remote Sensing 14, no. 5 (February 22, 2022): 1080. http://dx.doi.org/10.3390/rs14051080.
Повний текст джерелаАнотація:
3-D phase unwrapping (PU) methods based on the 2-D linear temporal coherencemodel have been widely used in time-series interferometric synthetic aperture radar (TS-InSAR) for measuring topography and monitoring subtle deformation. However, the linear temporal coherencemodel can not characterize the coherence of highly coherent pixels accurately in seasonal deformation areas, where nonlinear deformation is deterministic and nonnegligible. Especially, for urban areas with groundwater or thermal dilation seasonal changes or permafrost regions, the nonlinear deformation is usually associated with periodic temperature changes. In this work, a general multi-component temporal coherence model, which considers multiple components including the seasonal deformation, is proposed for 3-D PU of seasonal deformation areas. Moreover, the uncertainty evaluation criterion, based on Cramér–Rao bound (CRB), is derived for TS-InSAR. The experimental results, obtained by applying the multi-component temporal coherence model to a data set acquired from January 2012 to February 2016 over the Beijing Capital International Airport area, confirm the effectiveness of the proposed method. High phase consistency, accurate corrected digital elevation model (DEM) and deformation information monitoring with high-density and high-coverage PS pixels are achieved. Under the same iterations and TS-InSAR procedure, the enhanced performance by the proposed model is illustrated by comparing with that of linear model in terms of phase consistency of 3-D phase unwrapping, PSCs selection at each step, and final results evaluation. In summary, the number of phase-consistency edges after 3-D PU is increased by about 15%, the number of final PS pixels selected with the same coherence threshold constraint is increased by about 10%, and more PS pixels provide a low uncertainty in residual topography, mean deformation velocity and seasonal amplitude estimation.
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Tzouvaras, Marios, Chris Danezis, and Diofantos G. Hadjimitsis. "Small Scale Landslide Detection Using Sentinel-1 Interferometric SAR Coherence." Remote Sensing 12, no. 10 (May 14, 2020): 1560. http://dx.doi.org/10.3390/rs12101560.
Повний текст джерелаАнотація:
Infrastructure is operational under normal circumstances and is designed to cope with common natural disruptions such as rainfall and snow. Natural hazards can lead to severe problems at the areas where such phenomena occur, but also at neighboring regions as they can make parts of a road network virtually impassable. Landslides are one of the most devastating natural hazards worldwide, triggered by various factors that can be monitored via ground-based and/or satellite-based techniques. Cyprus is in an area of high susceptibility to such phenomena. Currently, extensive field campaigns including geotechnical drilling investigations and geophysical excavations are conducted to monitor land movements, and, at the same time, determine the geological suitability of areas. Active satellite remote sensors, namely Synthetic Aperture Radar (SAR), have been widely used for detecting and monitoring landslides and other ground deformation phenomena using Earth Observation based techniques. This paper aims to demonstrate how the use of Copernicus open-access and freely distributed datasets along with the exploitation of the open-source processing software SNAP (Sentinel’s Application Platform), provided by the European Space Agency, can be used for landslide detection, as in the case study near Pissouri, where a landslide was triggered by heavy rainfall on 15 February 2019, which caused a major disturbance to everyday commuters since the motorway connecting the cities of Limassol and Paphos remained closed for more than a month. The Coherent Change Detection (CCD) methodology was applied successfully by detecting the phenomenon under study accurately, using two indicators (the coherence difference and the normalized coherence difference). Receiver Operating Characteristic (ROC) analysis was carried out to measure their performance with the coherence difference having an overall accuracy of 93% and the normalized coherence difference having an overall accuracy of 94.8% for detecting the landslide and non-landslide areas. The probability of landslide detection was 63.2% in the case of the coherence difference and increased to 73.7% for the normalized coherence difference, whereas the probability of false alarm for both indicators was approximately 1%.
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Classen, Joseph, Christian Gerloff, Manabu Honda, and Mark Hallett. "Integrative Visuomotor Behavior Is Associated With Interregionally Coherent Oscillations in the Human Brain." Journal of Neurophysiology 79, no. 3 (March 1, 1998): 1567–73. http://dx.doi.org/10.1152/jn.1998.79.3.1567.
Повний текст джерелаАнотація:
Classen, Joseph, Christian Gerloff, Manabu Honda, and Mark Hallett. Integrative visuomotor behavior is associated with interregionally coherent oscillations in the human brain. J. Neurophysiol. 79: 1567–1573, 1998. Coherent electrical brain activity has been demonstrated to be associated with perceptual events in mammals. It is unclear whether or not it is also a mechanism instrumental in the performance of sensorimotor tasks requiring the continuous processing of information between primarily executive and receptive brain areas. In particular it is unknown whether or not interregional coherent activity detectable in electroencephalographic (EEG) recordings on the scalp reflects interareal functional cooperativity in humans. We studied patterns of changes in EEG-coherence associated with a visuomotor force-tracking task in seven subjects. Interregional coherence of EEG signals recorded from scalp regions overlying the visual and the motor cortex increased in comparison to a resting condition when subjects tracked a visual target by producing an isometric force with their right index finger. Coherence between visual and motor cortex decreased when the subjects produced a similar motor output in the presence of a visual distractor and was unchanged in a purely visual and purely motor task. Increases and decreases of coherence were best differentiated in the low beta frequency range (13–21 Hz). This observation suggests a special functional significance of low frequency oscillations in information processing in large-scale networks. These findings substantiate the view that coherent brain activity underlies integrative sensorimotor behavior.
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Chini, Marco, Ramona Pelich, Renaud Hostache, Patrick Matgen, and Carlos Lopez-Martinez. "Towards a 20 m Global Building Map from Sentinel-1 SAR Data." Remote Sensing 10, no. 11 (November 19, 2018): 1833. http://dx.doi.org/10.3390/rs10111833.
Повний текст джерелаАнотація:
This study introduces a technique for automatically mapping built-up areas using synthetic aperture radar (SAR) backscattering intensity and interferometric multi-temporal coherence generated from Sentinel-1 data in the framework of the Copernicus program. The underlying hypothesis is that, in SAR images, built-up areas exhibit very high backscattering values that are coherent in time. Several particular characteristics of the Sentinel-1 satellite mission are put to good use, such as its high revisit time, the availability of dual-polarized data, and its small orbital tube. The newly developed algorithm is based on an adaptive parametric thresholding that first identifies pixels with high backscattering values in both VV and VH polarimetric channels. The interferometric SAR coherence is then used to reduce false alarms. These are caused by land cover classes (other than buildings) that are characterized by high backscattering values that are not coherent in time (e.g., certain types of vegetated areas). The algorithm was tested on Sentinel-1 Interferometric Wide Swath data from five different test sites located in semiarid and arid regions in the Mediterranean region and Northern Africa. The resulting building maps were compared with the Global Urban Footprint (GUF) derived from the TerraSAR-X mission data and, on average, a 92% agreement was obtained.
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Zhang, Hai‐ying, Zhen‐fang Li, Zhi‐bin Wang, and Chao Fang. "Analysis of X‐band PolInSAR coherence characteristics in forested areas." IET Radar, Sonar & Navigation 11, no. 6 (May 2, 2017): 953–63. http://dx.doi.org/10.1049/iet-rsn.2016.0364.
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Loonen, Willem, Peter S. C. Heuberger, Aldrik H. Bakema, and Paul Schot. "Improving the Spatial Coherence of Nature Areas Using Genetic Algorithms." Environment and Planning B: Planning and Design 34, no. 2 (April 2007): 369–78. http://dx.doi.org/10.1068/b31184.
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Li, Yandong, Wenkai Lu, Huanqin Xiao, Shanwen Zhang, and Yanda Li. "Dip-scanning coherence algorithm using eigenstructure analysis and supertrace technique." GEOPHYSICS 71, no. 3 (May 2006): V61—V66. http://dx.doi.org/10.1190/1.2194899.
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The eigenstructure-based coherence algorithms are robust to noise and able to produce enhanced coherence images. However, the original eigenstructure coherence algorithm does not implement dip scanning; therefore, it produces less satisfactory results in areas with strong structural dips. The supertrace technique also improves the coherence algorithms’ robustness by concatenating multiple seismic traces to form a supertrace. In addition, the supertrace data cube preserves the structural-dip information that is contained in the original seismic data cube; thus, dip scanning can be performed effectively using a number of adjacent supertraces. We combine the eigenstructure analysis and the dip-scanning supertrace technique to obtain a new coherence-estimation algorithm. Application to the real data set shows that the new algorithm provides good coherence estimates in areas with strong structural dips. Furthermore, the algorithm is computationally efficient because of the small covariance matrix [Formula: see text] used for the eigenstructure analysis.
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SCHACK, BÄRBEL, PETER RAPPELSBERGER, CHRISTOPH ANDERS, SABINE WEISS, and EVA MÖLLER. "QUANTIFICATION OF SYNCHRONIZATION PROCESSES BY COHERENCE AND PHASE AND ITS APPLICATION IN ANALYSIS OF ELECTROPHYSIOLOGICAL SIGNALS." International Journal of Bifurcation and Chaos 10, no. 11 (November 2000): 2565–86. http://dx.doi.org/10.1142/s0218127400001651.
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Neuronal activity during information processing and muscle activity are generally characterized by oscillations. Mostly, widespread areas are involved and electrophysiological signals are measured on different sites of the cortex or of the muscle. In order to investigate functional relationships between different components of multidimensional electrophysiological signals, coherence and phase analyses turned out to be useful tools. These parameters allow the investigation of synchronization phenomena with regard to oscillations of defined frequencies or frequency bands. Coherence and phase are closely connected spectral parameters. Coherence may be understood as a measure of phase stability. Whereas coherence describes the amount of common information with regard to oscillations within certain frequency bands, the corresponding phase, from which time delays of these oscillations can be computed, hints at the direction of information transfer through oscillation. Coherence and phase analysis of surface EMG during continuous activity of deep and superficial muscles show distinct differences due to volume conduction properties of myoelectrical signals. Superficial activity therefore is characterized by significant coherence and stable phase relationships, which, additionally, can be used to determine motor unit action potential (MUAP) propagation velocity along the fibre direction without application of invasive methods. Deep muscle activity lacks significant coherence. Mental processes can be very brief and cooperation between different areas may be highly dynamic. For this reason in addition to usual Fourier estimation of coherence and phase, a two-dimensional approach of adaptive filtering was developed to estimate coherence and phase continuously in time. Statistical and dynamic properties of instantaneous phase are discussed. In order to demonstrate the value of this method for studying higher cognitive processes the method was applied to EEG recorded during word processing. During visual presentation of abstract nouns an information transfer through the propagation of oscillations from visual areas to frontal association areas in the α1-frequency band could be verified within the first 400 ms. In contrast, in case of auditory presentation positive phases from the temporal electrode locations T3 and T4 towards the occipital areas appear within the time interval of 300 ms–600 ms. The α1-band predominately seems to reflect sensory processing and attention processes.
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Shi, Yueling, Guoxiang Liu, Xiaowen Wang, Qiao Liu, Rui Zhang, and Hongguo Jia. "Assessing the Glacier Boundaries in the Qinghai-Tibetan Plateau of China by Multi-Temporal Coherence Estimation with Sentinel-1A InSAR." Remote Sensing 11, no. 4 (February 15, 2019): 392. http://dx.doi.org/10.3390/rs11040392.
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The sensitivity of synthetic aperture radar (SAR) coherence has been applied in delineating the boundaries of alpine glaciers because it is nearly unaffected by cloud coverage and can collect data day and night. However, very limited work with application of SAR data has been performed for the alpine glaciers in the Qinghai-Tibetan Plateau (QTP) of China. In this study, we attempted to investigate the change of coherence level in alpine glacier zone and access the glacier boundaries in the QTP using time series of Sentinel-1A SAR images. The DaDongkemadi Glacier (DDG) in the central QTP was selected as the study area with land cover mainly classified into wet snow, ice, river outwash and soil land. We utilized 45 Sentinel-1A C-band SAR images collected during October of 2014 through January of 2018 over the DDG to generate time series of interferometric coherence maps, and to further extract the DDG boundaries. Based on the spatiotemporal analysis of coherence values in the selected sampling areas, we first determined the threshold as 0.7 for distinguishing among different ground targets and then extracted the DDG boundaries through threshold-based segmentation and edge detection. The validation was performed by comparing the DDG boundaries extracted from the coherence maps with those extracted from the Sentinel-2B optical image. The testing results show that the wet snow and ice present a relatively low level of coherence (about 0.5), while the river outwash and the soil land present a higher level of coherence (0.8–1.0). It was found that the coherence maps spanning between June and September (i.e., the glacier ablation period) are the most suitable for identifying the snow- and ice-covered areas. When compared with the boundary detected using optical image, the mean value of Jaccard similarity coefficient for the total areas within the DDG boundaries derived from the coherence maps selected around July, August and September reached up to 0.9010. In contrast, the mean value from the coherence maps selected around December was relatively lower (0.8862). However, the coherence maps around December were the most suitable for distinguishing the ice from the river outwash around the DDG terminus, as the river outwash areas could hardly be differentiated from the ice-covered areas from June through September. The correlation analysis performed by using the meteorological data (i.e., air temperature and precipitation records) suggests that the air temperature and precipitation have a more significant influence on the coherence level of the ice and river outwash than the wet snow and soil land. The proposed method, applied efficiently in this study, shows the potential of multi-temporal coherence estimation from the Sentinel-1A mission to access the boundaries of alpine glaciers on a larger scale in the QTP.
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Ma, Li, Wentai Liu, and Andrew E. Hudson. "Propofol Anesthesia Increases Long-range Frontoparietal Corticocortical Interaction in the Oculomotor Circuit in Macaque Monkeys." Anesthesiology 130, no. 4 (April 1, 2019): 560–71. http://dx.doi.org/10.1097/aln.0000000000002637.
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Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Frontoparietal functional connectivity decreases with multiple anesthetics using electrophysiology and functional imaging. This decrease has been proposed as a final common functional pathway to produce anesthesia. Two alternative measures of long-range cortical interaction are coherence and phase-amplitude coupling. Although phase-amplitude coupling within frontal cortex changes with propofol administration, the effects of propofol on phase-amplitude coupling between different cortical areas have not previously been reported. Based on phase-amplitude coupling observed within frontal lobe during the anesthetized period, it was hypothesized that between-lead phase-amplitude coupling analysis should decrease between frontal and parietal leads during propofol anesthesia. Methods A published monkey electrocorticography data set (N = 2 animals) was used to test for interactions in the cortical oculomotor circuit, which is robustly interconnected in primates, and in the visual system during propofol anesthesia using coherence and interarea phase-amplitude coupling. Results Propofol induces coherent slow oscillations in visual and oculomotor networks made up of cortical areas with strong anatomic projections. Frontal eye field within-area phase-amplitude coupling increases with a time course consistent with a bolus response to intravenous propofol (modulation index increase of 12.6-fold). Contrary to the hypothesis, interareal phase-amplitude coupling also increases with propofol, with the largest increase in phase-amplitude coupling in frontal eye field low-frequency phase modulating lateral intraparietal area β-power (27-fold increase) and visual area 2 low-frequency phase altering visual area 1 β-power (19-fold increase). Conclusions Propofol anesthesia induces coherent oscillations and increases certain frontoparietal interactions in oculomotor cortices. Frontal eye field and lateral intraparietal area show increased coherence and phase-amplitude coupling. Visual areas 2 and 1, which have similar anatomic projection patterns, show similar increases in phase-amplitude coupling, suggesting higher order feedback increases in influence during propofol anesthesia relative to wakefulness. This suggests that functional connectivity between frontal and parietal areas is not uniformly decreased by anesthetics.
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LIPPL, STEFAN, SAURABH VIJAY, and MATTHIAS BRAUN. "Automatic delineation of debris-covered glaciers using InSAR coherence derived from X-, C- and L-band radar data: a case study of Yazgyl Glacier." Journal of Glaciology 64, no. 247 (September 25, 2018): 811–21. http://dx.doi.org/10.1017/jog.2018.70.
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ABSTRACTDespite their importance for mass-balance estimates and the progress in techniques based on optical and thermal satellite imagery, the mapping of debris-covered glacier boundaries remains a challenging task. Manual corrections hamper regular updates. In this study, we present an automatic approach to delineate glacier outlines using interferometrically derived synthetic aperture radar (InSAR) coherence, slope and morphological operations. InSAR coherence detects the temporally decorrelated surface (e.g. glacial extent) irrespective of its surface type and separates it from the highly coherent surrounding areas. We tested the impact of different processing settings, for example resolution, coherence window size and topographic phase removal, on the quality of the generated outlines. We found minor influence of the topographic phase, but a combination of strong multi-looking during interferogram generation and additional averaging during coherence estimation strongly deteriorated the coherence at the glacier edges. We analysed the performance of X-, C- and L- band radar data. The C-band Sentinel-1 data outlined the glacier boundary with the least misclassifications and a type II error of 0.47% compared with Global Land Ice Measurements from Space inventory data. Our study shows the potential of the Sentinel-1 mission together with our automatic processing chain to provide regular updates for land-terminating glaciers on a large scale.
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Molinari, M. E., A. Monti-Guarnieri, and M. Manzoni. "A NOVEL INDEX FOR TEMPORAL STABILITY ANALYSIS IN SPACE AND TIME OF SAR-DERIVED SCENES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2020 (August 22, 2020): 1577–83. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2020-1577-2020.
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Abstract. Detecting temporal changes is one of the most important applications of satellite sensors. In recent years, the increasing availability of regular time-series of SAR imagery, provided by the Sentinel-1 mission of the European Space Agency (ESA), has drawn increasing attention to these techniques, especially in earth environment monitoring and risk management. Within this paper, a coherent change detection analysis for evaluating the risk due to movements of dunes and sand sheets in desertic areas is proposed. To this purpose, we introduce a novel, coherence-based index, named Temporal Stability Index (TSI), that is suited for characterizing the percentage of stability of a target with time. TSI maps can be generated over areas as wide as hundreds of kilometers, in a short time, and mostly by exploiting available software tools (plus some simple coding). The information provided is complementary to the average of the short-term coherence, here shown. Results of analysis performed on two desertic regions (the United Arab Emirates and Egypt) document the usefulness of TSI for the identification of dune movements and areas subject to sand accumulation, supporting risk mitigation measures.
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Petsche, Hellmuth, Peter Richter, Astrid Von Stein, Susan C. Etlinger, and Oliver Filz. "EEG Coherence and Musical Thinking." Music Perception 11, no. 2 (1993): 117–51. http://dx.doi.org/10.2307/40285613.
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This study was performed to test the usefulness of the EEG as a research instrument for music psychology in individuals. Measuring the degree of functional interrelatedness of brain areas by coherence estimates has turned out to be more efficient than amplitude mapping. Therefore, the method, based on the analysis of EEG periods of at least 1 min, has been expanded to estimate all possible coherence values between the 19 electrodes (i.e., 171 values) and to observe any significant changes in those values caused by different musical tasks. This report concerns observations in a total of 49 healthy subjects (29 male and 20 female). The main goal of this study was to determine the degree of engagement of either hemisphere in the processing of music. Two items were shown to indicate hemispheric involvement: (1) the topographic distribution of "focal points of coherence" (brain areas participating in coherence changes with respect to a great number of other brain areas) and (2) the number of intrahemispheric coherence increases. In most cases, both items seem to focus on the same hemisphere. Taking these as parameters for hemispheric engagement, the following principal observations were made: the beta bands (and particularly their uppermost ranges) seem to play a major role in the processing of music; the hemispheric engagement, however, need not be the same for each frequency band. No hemisphere seems to be preferred. When listening to music is shifted between different styles, laterality may change. When the same tasks are repeated at several weeks' intervals, a fairly large degree of consistency is found. Imagining music and composing clearly differs from listening by activating many more coherence increases in the beta band and by an increasing percentage of hemispheric interaction. This kind of analysis may also provide some clues as to how a piece of music is processed by an individual. The coherence changes observed may represent events taking place in a system of differential attention that selects and orders the sensory inputs before the musical material is further processed at higher order hierarchical levels.
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Selmi, S., W. Ben Abdallah, and R. Abdelfatteh. "Flood Mapping Using InSAR Coherence Map." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-7 (September 19, 2014): 161–64. http://dx.doi.org/10.5194/isprsarchives-xl-7-161-2014.
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Classic approaches for the detection of flooded areas are based on a static analysis of optical images and/or SAR data during and after the event. In this paper, we aim to extract the flooded zones by using the SAR image coupled with the InSAR coherence. A new formulation of the ratio approach for flood detection is given considering InSAR coherence. Our contribution is to take advantage from the coherence map provided using the InSAR pairs (one before and one after the event) to enhance the detection of flooded areas. We explore the fact that the coherence values during and after the flood are mainly differents on the flooded zones and we give a more suitable flood decision rule using this assumption. The proposed approach is tested and validated in the case of the flood taken place in 2005 in the region of Kef in Tunisia.
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Belskaya, Ksenia A., Yuliya V. Surovitskaya, and Sergey A. Lytaev. "Spatio-Temporal EEG Markers for Recognition Auditory Images in Norm and Psychopathology." Pediatrician (St. Petersburg) 7, no. 3 (September 15, 2016): 49–55. http://dx.doi.org/10.17816/ped7349-55.
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The psychophysiological mechanisms of cognitive processes dysfunctions remain poorly understood. The purpose of this study was to modeling spatial-temporal parameters of coherent EEG assessment during auditory recognition in normal conditions and psychopathology. 40 healthy subjects and 72 patients with homogeneous psychopathological states depressive nature (average age of 34 ± 3.4 years) using the standard and original research methods were investigated. Individual-psychological characteristics and the severity of cognitive defect was evaluated according to the clinical interview, research verbal memory, the traditional methods of evaluating situational and personal anxiety, the differential diagnosis of depression. The study was conducted in St Petersburg “Psycho-Neurological Clinic No 1”. We have used the original method of studying the perception of auditory images, audiometry, computer electroencephalography with multidimensional mathematical treatment and psychological analysis of higher mental functions in patients with paranoid schizophrenia and control normal subjects. Analysis of coherence alpha- and beta-EEG rhythms in solving cognitive tasks for recognition of auditory images revealed that the functional interaction of the cortical areas normally significantly increased compared to background EEG. The features of the topography of functional relationships of alpha- and beta-EEG rhythms in the perception of auditory information are confirmed. Focuses interactions are recorded in the frontal areas. It marked the integration of these frontal zones with front associative cortex and temporal areas of the left hemisphere, as well as parietal and occipital areas of both hemispheres. At psychopathology reducing the number of coherent communications, violation of the formation of foci of coherence was registered.
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Shimaoka, Daisuke, Keiichi Kitajo, Kunihiko Kaneko, and Yoko Yamaguchi. "Role of spontaneous phase coherence across cortical areas on visual perception." Neuroscience Research 71 (September 2011): e178. http://dx.doi.org/10.1016/j.neures.2011.07.771.
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Fortin, A., A. Ptito, J. Faubert, A. Gjedde, R. Kupers, and M. Ptito. "Cortical areas associated with stereodepth as a function of coherence levels." NeuroImage 13, no. 6 (June 2001): 878. http://dx.doi.org/10.1016/s1053-8119(01)92220-7.
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Fan, Qinghui, Deliang Xiang, and Chongyuan Fan. "New polarimetric coherence parameter for built‐up areas in PolSAR imagery." Electronics Letters 54, no. 3 (February 2018): 159–61. http://dx.doi.org/10.1049/el.2017.3299.
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Bonnet, Clemence, Giuseppe Querques, Jennyfer Zerbib, Hassiba Oubraham, Rocio B. Garavito, Nathalie Puche, and Eric H. Souied. "HYPERREFLECTIVE PYRAMIDAL STRUCTURES ON OPTICAL COHERENCE TOMOGRAPHY IN GEOGRAPHIC ATROPHY AREAS." Retina 34, no. 8 (August 2014): 1524–30. http://dx.doi.org/10.1097/iae.0000000000000165.
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Qian, Qian, Bingnan Wang, Xiaoning Hu, and Maosheng Xiang. "Coherent Markov Random Field-Based Unreliable DSM Areas Segmentation and Hierarchical Adaptive Surface Fitting for InSAR DEM Reconstruction." Sensors 20, no. 5 (March 4, 2020): 1414. http://dx.doi.org/10.3390/s20051414.
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A digital elevation model (DEM) can be obtained by removing ground objects, such as buildings, in a digital surface model (DSM) generated by the interferometric synthetic aperture radar (InSAR) system. However, the imaging mechanism will cause unreliable DSM areas such as layover and shadow in the building areas, which seriously affect the elevation accuracy of the DEM generated from the DSM. Driven by above problem, this paper proposed a novel DEM reconstruction method. Coherent Markov random field (CMRF) was first used to segment unreliable DSM areas. With the help of coherence coefficients and residue information provided by the InSAR system, CMRF has shown better segmentation results than traditional traditional Markov random field (MRF) which only use fixed parameters to determine the neighborhood energy. Based on segmentation results, the hierarchical adaptive surface fitting (with gradually changing the grid size and adaptive threshold) was set up to locate the non-ground points. The adaptive surface fitting was superior to the surface fitting-based method with fixed grid size and threshold of height differences. Finally, interpolation based on an inverse distance weighted (IDW) algorithm combining coherence coefficient was performed to reconstruct a DEM. The airborne InSAR data from the Institute of Electronics, Chinese Academy of Sciences has been researched, and the experimental results show that our method can filter out buildings and identify natural terrain effectively while retaining most of the terrain features.
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Živkov, Dejan, Jovan Njegić, and Marko Pećanac. "Multiscale interdependence between the major agricultural commodities." Agricultural Economics (Zemědělská ekonomika) 65, No. 2 (February 27, 2019): 82–92. http://dx.doi.org/10.17221/147/2018-agricecon.
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This paper investigates multiscale dynamic interconnection between the five agricultural commodities – corn, wheat, soybean, rice and oats, covering more than 18 years period. For research purposes, two complementary methodologies were used – wavelet coherence and phase difference. Low coherence is present at shorter time-horizons, while at longer time-horizons high coherence areas are found, but they are not widespread in all wavelet coherence plots. These results speak in favour of diversification opportunities. Strong coherence in longer time-horizons indicates that common factors are likely to be the main determinants of the agricultural prices in the long-run. On the other hand, rare high coherence areas at lower scales suggest that monetary and financial activities are most likely the causes that have affected the comovements of the grain prices in the short-term horizons. Phase difference discloses a relatively stable pattern between corn-soybean, corn-wheat, rice-oats and oats-soybean in the longer time-horizons. Taking into account investors’ diversification benefits and the leading (lagging) connections in long-run, corn and oats are the most appropriate cereals to be combined in an n-asset portfolio, since these two cereals constantly and very steadily lag soybean, whereas strong coherence between corn and oats does not frequently occur in all wavelet scales.
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Fajkowska, Małgorzata. "Personality coherence: Advances in theory, assessment, and research." European Journal of Personality 36, no. 3 (March 20, 2022): 267–73. http://dx.doi.org/10.1177/08902070221084520.
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This special issue of the European Journal of Personality, entitled Towards conceptualizing and assessing personality coherence and incoherence, was designed to call for new approaches to the understanding and assessment of personality coherence. Seven papers have been brought together as a result: three theoretical and four empirical Although these papers are devoted to portraying novel or expanded existing conceptual and methodological approaches to personality coherence, they also share a historic commitment to studying this phenomenon. Based on those contributions, I refer to the four topics: (1) novel, extended, validated models of personality coherence, (2) personality coherence and related constructs, (3) functional/adaptive meaning of personality coherence, and (4) assessment-related issues that help display advances in the theory, measurement, and research on personality coherence. In addition, I present four areas that have been identified as avenues for future research: (1) potentials for further developing the personality coherence field, (2) personality coherence, self, and character, (4) personality coherence and development, and (4) personality coherence across different cultures.
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Takei, Tomohiko, and Kazuhiko Seki. "Spinomuscular Coherence in Monkeys Performing a Precision Grip Task." Journal of Neurophysiology 99, no. 4 (April 2008): 2012–20. http://dx.doi.org/10.1152/jn.01181.2007.
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We recorded local field potentials (LFPs) from cervical spinal cord (C5–C8) in monkeys performing a precision grip task and examined their coherence with electromyographic (EMG) activities (spinomuscular coherence) recorded from hand and arm muscles. Among 164 LFP-EMG pairs, significant coherence was found in 34 pairs (21%). We classified the coherence into two groups based on its frequency range, narrowband coherence, and broadband coherence. The narrowband coherence was restricted to discrete frequencies in the range of 14–55 Hz and was widespread throughout the superficial and deep gray matter. In contrast, the broadband coherence distributed between 10 and 95 Hz and was found only in the ventral half of the spinal cord. The narrowband coherence suggests that oscillations, which have been described in many motor control areas of the brain, could also pass though spinal interneurons to affect motor output and sensorimotor integration. On the other hand, the broadband coherence could be a unique feature of spinal motoneuron-muscle physiology.
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Canisius, Francis, Brian Brisco, Kevin Murnaghan, Marco Van Der Kooij, and Edwin Keizer. "SAR Backscatter and InSAR Coherence for Monitoring Wetland Extent, Flood Pulse and Vegetation: A Study of the Amazon Lowland." Remote Sensing 11, no. 6 (March 26, 2019): 720. http://dx.doi.org/10.3390/rs11060720.
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Synthetic aperture radar (SAR) data have been identified as a potential source of information for monitoring surface water, including open water and flooded vegetation, in frequent time intervals, which is very significant for flood mapping applications. The SAR specular reflectance separates open water and land surface, and its canopy penetration capability allows enhanced backscatter from flooded vegetation. Further, under certain conditions, the SAR signal from flooded vegetation may remain coherent between two acquisitions, which can be exploited using the InSAR technique. With these SAR capabilities in mind, this study examines the use of multi-temporal RADARSAT-2 C band SAR intensity and coherence components to monitor wetland extent, inundation and vegetation of a tropical wetland, such as Amazon lowland. For this study, 22 multi-temporal RADARSAT-2 images (21 pairs) were used for InSAR processing and the pairs in the low water stage (November, December) showed high coherence over the wetland areas. The three-year intensity stack was used for assessing wetland boundary, inundation extent, flood pulse, hydroperiod, and wetland vegetation. In addition to the intensity, derived coherence was used for classifying wetland vegetation. Wetland vegetation types were successfully classified with 86% accuracy using the statistical parameters derived from the multi-temporal intensity and coherence data stacks. We have found that in addition to SAR intensity, coherence provided information about wetland vegetation. In the next year, the Canadian RADARSAT Constellation Mission (RCM), will provide more data with frequent revisits, enhancing the application of SAR intensity and coherence for monitoring these types of wetlands at large scales.
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Libak, Audun, Behzad Alaei, and Anita Torabi. "Fault visualization and identification in fault seismic attribute volumes: Implications for fault geometric characterization." Interpretation 5, no. 2 (May 31, 2017): B1—B16. http://dx.doi.org/10.1190/int-2016-0152.1.
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Fault seismic attribute volumes (such as volumetric coherence and curvature) represent an efficient and objective way to visualize and identify faults in seismic cubes. Fault geometric attributes such as length, height, and fault segmentation can be extracted from such fault seismic attribute volumes. We evaluate the strengths and pitfalls of using coherence volumes for characterization of fault geometry. The results are obtained using a database from the Barents Sea, which contains 35 3D seismic cubes, together with conceptual synthetic seismic models. A high signal-to-noise ratio is a requirement for the extraction of accurate fault geometric data. Noise attenuation methods improve fault visualization, but our results indicate that the effect of noise attenuation on the extracted fault geometric attributes is only clear in areas of low signal-to-noise ratios. The choice of coherence algorithm is important when extracting fault length data. Semblance-based coherence performs better than gradient structure tensor-based coherence in low-displacement areas near the fault tips, and it produces more accurate fault length data. Faults can appear segmented in coherence volumes if relatively similar reflectors are juxtaposed across a fault. In such areas, it is important that the interpreter does not overlook the fault. The size of the analysis window used in coherence calculations controls the resolution and continuity of the imaged faults. Our results support an optimal temporal window size of one to two times the dominant period of the seismic data (typically 7–17 samples in conventional 4 ms sampled 3D seismic data). Larger temporal window sizes can result in an overestimation of fault height, especially for small faults. A large spatial window can smear out segmentation along the fault and make the fault traces wider. Even though a large spatial window can have some positive effects, we recommend using a relatively small spatial window (five traces) when extracting subtle fault geometric attributes.
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Kiper, D. C., M. G. Knyazeva, L. Tettoni, and G. M. Innocenti. "Visual Stimulus–Dependent Changes in Interhemispheric EEG Coherence in Ferrets." Journal of Neurophysiology 82, no. 6 (December 1, 1999): 3082–94. http://dx.doi.org/10.1152/jn.1999.82.6.3082.
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In recent years, the analysis of the coherence between signals recorded from the scalp [electroencephalographic (EEG) coherence] has been used to assess the functional properties of cortico-cortical connections, both in animal models and in humans. However, the experimental validation of this technique is still scarce. Therefore we applied it to the study of the callosal connections between the visual areas of the two hemispheres, because this particular set of cortico-cortical connections can be activated in a selective way by visual stimuli. Indeed, in primary and in low-order secondary visual areas, callosal axons interconnect selectively regions, which represent a narrow portion of the visual field straddling the vertical meridian and, within these regions, neurons that prefer the same stimulus orientation. Thus only isooriented stimuli located near the vertical meridian are expected to change interhemispheric coherence by activating callosal connections. Finally, if such changes are found and are indeed mediated by callosal connections, they should disappear after transection of the corpus callosum. We perfomed experiments on seven paralyzed and anesthetized ferrets, recording their cortical activity with epidural electrodes on areas 17/18, 19, and lateral suprasylvian, during different forms of visual stimulation. As expected, we found that bilateral iso-oriented stimuli near the vertical meridian, or extending across it, caused a significant increase in interhemispheric coherence in the EEG beta-gamma band. Stimuli with different orientations, stimuli located far from the vertical meridian, as well as unilateral stimuli failed to affect interhemispheric EEG coherence. The stimulus-induced increase in coherence disappeared after surgical transection of the corpus callosum. The results suggest that the activation of cortico-cortical connections can indeed be revealed as a change in EEG coherence. The latter can therefore be validly used to investigate the functionality of cortico-cortical connections.
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Li, Yu, Sandro Martinis, Marc Wieland, Stefan Schlaffer, and Ryo Natsuaki. "Urban Flood Mapping Using SAR Intensity and Interferometric Coherence via Bayesian Network Fusion." Remote Sensing 11, no. 19 (September 25, 2019): 2231. http://dx.doi.org/10.3390/rs11192231.
Повний текст джерелаАнотація:
Synthetic Aperture Radar (SAR) observations are widely used in emergency response for flood mapping and monitoring. However, the current operational services are mainly focused on flood in rural areas and flooded urban areas are less considered. In practice, urban flood mapping is challenging due to the complicated backscattering mechanisms in urban environments and in addition to SAR intensity other information is required. This paper introduces an unsupervised method for flood detection in urban areas by synergistically using SAR intensity and interferometric coherence under the Bayesian network fusion framework. It leverages multi-temporal intensity and coherence conjunctively to extract flood information of varying flooded landscapes. The proposed method is tested on the Houston (US) 2017 flood event with Sentinel-1 data and Joso (Japan) 2015 flood event with ALOS-2/PALSAR-2 data. The flood maps produced by the fusion of intensity and coherence and intensity alone are validated by comparison against high-resolution aerial photographs. The results show an overall accuracy of 94.5% (93.7%) and a kappa coefficient of 0.68 (0.60) for the Houston case, and an overall accuracy of 89.6% (86.0%) and a kappa coefficient of 0.72 (0.61) for the Joso case with the fusion of intensity and coherence (only intensity). The experiments demonstrate that coherence provides valuable information in addition to intensity in urban flood mapping and the proposed method could be a useful tool for urban flood mapping tasks.
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Teixeira, S., B. Velasques, S. Machado, F. Paes, M. Cunha, H. Budde, R. Anghinah, et al. "Gamma band oscillations in parietooccipital areas during performance of a sensorimotor integration task: a qEEG coherence study." Arquivos de Neuro-Psiquiatria 69, no. 2b (2011): 304–9. http://dx.doi.org/10.1590/s0004-282x2011000300007.
Повний текст джерелаАнотація:
This study aimed to elucidate cortical mechanisms involved in anticipatory actions when 23 healthy right-handed subjects had to catch a free falling object through quantitative electroencephalogram (qEEG). For this reason, we used coherence that represents a measurement of linear covariation between two signals in the frequency domain. In addition, we investigated gamma-band (30-100 Hz) activity that is related to cognitive and somatosensory processes. We hypothesized that gamma coherence will be increase in both parietal and occipital areas during moment after ball drop, due to their involvement in manipulation of objects, visuospatial processing, visual perception, stimuli identification and attention processes. We confirmed our hypothesis, an increase in gamma coherence on P3-P4 (t= -2.15; p=0.033) and PZ-OZ (t= -2.16; p=0.034) electrode pairs was verified for a paired t-test. We conclude that to execute tasks involving anticipatory movements (feedforward mechanisms), like our own task, probably, there is no need of a strong participation of visual areas in the process of information organization to manipulate objects and to process visuospatial information regarding the contact hand-object.
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Garcia-Arumi Fuste, Claudia, Federico Peralta Iturburu, and Jose Garcia-Arumi. "Is optical coherence tomography angiography helpful in the differential diagnosis of choroidal nevus versus melanoma?" European Journal of Ophthalmology 30, no. 4 (June 18, 2019): 723–29. http://dx.doi.org/10.1177/1120672119851768.
Повний текст джерелаАнотація:
Purpose: To describe the imaging features of choroidal nevus and melanoma using optical coherence tomography angiography, and evaluate the ability of this technique to establish the differential diagnosis based on the display of the tumor’s intrinsic vasculature. Methods: Comparative analysis of optical coherence tomography angiography findings in consecutive patients diagnosed with choroidal nevus or choroidal melanoma following a complete ophthalmic evaluation, including best-corrected visual acuity and several imaging studies: color fundus photography, B-scan ultrasound, spectral-domain optical coherence tomography, and optical coherence tomography angiography. Optical coherence tomography angiography was used to investigate qualitative differences in the tumor vasculature. Results: Thirty-six eyes (18 cases of choroidal nevus and 18 cases of choroidal melanoma) from 36 consecutive patients were included in the study. Only cases located posterior to equator were included to enable performance of all tests. On optical coherence tomography angiography, choroidal nevus showed well-delimited margins (78%), hyperreflective choroid capillary vasculature (83%), fewer avascular areas (17%), and neovascular membrane in one case (6%). Choroidal melanoma showed imprecise margins (72%), hyporeflective choroidal capillary vasculature (72%), multiple avascular areas (78%), and choroidal vascular changes (e.g. thick vascular networks or vascular loops; 45%). Conclusion: Optical coherence tomography angiography can provide useful information for assessing and differentiating between choroidal nevi and small melanomas. Significant differences between these conditions were found for the pattern of reflectivity, and presence/absence of avascular zones and vascular anomalies, which could be helpful for supporting the diagnosis.
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Invernizzi, Alessandro, Aniruddha Agarwal, Mariano Cozzi, Francesco Viola, Quan Dong Nguyen, and Giovanni Staurenghi. "ENHANCED DEPTH IMAGING OPTICAL COHERENCE TOMOGRAPHY FEATURES IN AREAS OF CHORIOCAPILLARIS HYPOPERFUSION." Retina 36, no. 10 (October 2016): 2013–21. http://dx.doi.org/10.1097/iae.0000000000001031.
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Finke, M., S. Kantelhardt, A. Schlaefer, R. Bruder, E. Lankenau, A. Giese, and A. Schweikard. "Automatic scanning of large tissue areas in neurosurgery using optical coherence tomography." International Journal of Medical Robotics and Computer Assisted Surgery 8, no. 3 (March 26, 2012): 327–36. http://dx.doi.org/10.1002/rcs.1425.
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Morishita, Yu, and Ramon F. Hanssen. "Deformation Parameter Estimation in Low Coherence Areas Using a Multisatellite InSAR Approach." IEEE Transactions on Geoscience and Remote Sensing 53, no. 8 (August 2015): 4275–83. http://dx.doi.org/10.1109/tgrs.2015.2394394.
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Sherman, D. L., S. S. Nathan, N. E. Crone, R. P. Lesser, B. Gordon, and N. V. Thakor. "Electrocorticographic coherence mapping reveals tongue activation areas of the human sensorimotor cortex." Electroencephalography and Clinical Neurophysiology 95, no. 2 (August 1995): P21—P22. http://dx.doi.org/10.1016/0013-4694(95)97936-u.
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