Relevant bibliographies by topics / Spatial response function

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Spatial response function'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Spatial response function"

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Frans, E. P., and R. A. Schowengerdt. "Improving Spatial-Spectral Unmixing with the Sensor Spatial Response Function." Canadian Journal of Remote Sensing 25, no. 2 (June 1999): 131–51. http://dx.doi.org/10.1080/07038992.1999.10874712.

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Lindsley, Richard D., Craig Anderson, Julia Figa-Saldana, and David G. Long. "A Parameterized ASCAT Measurement Spatial Response Function." IEEE Transactions on Geoscience and Remote Sensing 54, no. 8 (August 2016): 4570–79. http://dx.doi.org/10.1109/tgrs.2016.2544835.

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Lei, Xuefeng, Shuangshuang Zhu, Zhenyang Li, Jin Hong, Zhenhai Liu, Fei Tao, Peng Zou, Maoxin Song, and Congfei Li. "Integration model of POSP measurement spatial response function." Optics Express 28, no. 17 (August 14, 2020): 25480. http://dx.doi.org/10.1364/oe.393897.

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Williford, Tori, and John H. R. Maunsell. "Effects of Spatial Attention on Contrast Response Functions in Macaque Area V4." Journal of Neurophysiology 96, no. 1 (July 2006): 40–54. http://dx.doi.org/10.1152/jn.01207.2005.

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Previous single-unit studies of visual cortex have reported that spatial attention modulates responses to different orientations and directions proportionally, such that it does not change the width of tuning functions for these properties. Other studies have suggested that spatial attention causes a leftward shift in contrast response functions, such that its effects on responses to stimuli of different contrasts are not proportional. We have further explored the effects of attention on stimulus-response functions by measuring the responses of 131 individual V4 neurons in two monkeys while they did a task that controlled their spatial attention. Each neuron was tested with a set of stimuli that spanned complete ranges of orientation and contrast during different states of attention. Consistent with earlier reports, attention scaled responses to preferred and nonpreferred orientations proportionally. However, we did not find compelling evidence that the effects were best described by a leftward shift of the contrast response function. The modulation of neuronal responses by attention was well described by either a leftward shift or proportional scaling of the contrast response function. Consideration of differences in experimental design and analysis that may have contributed to this discrepancy suggests that it was premature to exclude a proportional scaling of responses to different contrasts by attention in favor of a leftward shift of contrast response functions. The current results reopen the possibility that the effects of attention on stimulus-response functions are well described by a single proportional increase in a neuron's response to all stimuli.
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Kabara, Joseph F., and A. B. Bonds. "Modification of Response Functions of Cat Visual Cortical Cells by Spatially Congruent Perturbing Stimuli." Journal of Neurophysiology 86, no. 6 (December 1, 2001): 2703–14. http://dx.doi.org/10.1152/jn.2001.86.6.2703.

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Responses of cat striate cortical cells to a drifting sinusoidal grating were modified by the superimposition of a second, perturbing grating (PG) that did not excite the cell when presented alone. One consequence of the presence of a PG was a shift in the tuning curves. The orientation tuning of all 41 cells exposed to a PG and the spatial frequency tuning of 83% of the 23 cells exposed to a PG showed statistically significant dislocations of both the response function peak and center of mass from their single grating values. As found in earlier reports, the presence of PGs suppressed responsiveness. However, reductions measured at the single grating optimum orientation or spatial frequency were on average 1.3 times greater than the suppression found at the peak of the response function modified by the presence of the PG. Much of the loss in response seen at the single grating optimum is thus a result of a shift in the tuning function rather than outright suppression. On average orientation shifts were repulsive and proportional (∼0.10 deg/deg) to the angle between the perturbing stimulus and the optimum single grating orientation. Shifts in the spatial frequency response function were both attractive and repulsive, resulting in an overall average of zero. For both simple and complex cells, PGs generally broadened orientation response function bandwidths. Similarly, complex cell spatial frequency response function bandwidths broadened. Simple cell spatial frequency response functions usually did not change, and those that did broadened only 4% on average. These data support the hypothesis that additional sinusoidal components in compound stimuli retune cells' response functions for orientation and spatial frequency.
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Frey, E. C., and B. M. W. Tsui. "Spatial properties of the scatter response function in SPECT." IEEE Transactions on Nuclear Science 38, no. 2 (April 1991): 789–94. http://dx.doi.org/10.1109/23.289392.

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Sun, Kang, Lei Zhu, Karen Cady-Pereira, Christopher Chan Miller, Kelly Chance, Lieven Clarisse, Pierre-François Coheur, et al. "A physics-based approach to oversample multi-satellite, multispecies observations to a common grid." Atmospheric Measurement Techniques 11, no. 12 (December 18, 2018): 6679–701. http://dx.doi.org/10.5194/amt-11-6679-2018.

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Abstract. Satellite remote sensing of the Earth's atmospheric composition usually samples irregularly in space and time, and many applications require spatially and temporally averaging the satellite observations (level 2) to a regular grid (level 3). When averaging level 2 data over a long period to a target level 3 grid that is significantly finer than the sizes of level 2 pixels, this process is referred to as “oversampling”. An agile, physics-based oversampling approach is developed to represent each satellite observation as a sensitivity distribution on the ground, instead of a point or a polygon as assumed in previous methods. This sensitivity distribution can be determined by the spatial response function of each satellite sensor. A generalized 2-D super Gaussian function is proposed to characterize the spatial response functions of both imaging grating spectrometers (e.g., OMI, OMPS, and TROPOMI) and scanning Fourier transform spectrometers (e.g., GOSAT, IASI, and CrIS). Synthetic OMI and IASI observations were generated to compare the errors due to simplifying satellite fields of view (FOVs) as polygons (tessellation error) and the errors due to discretizing the smooth spatial response function on a finite grid (discretization error). The balance between these two error sources depends on the target grid size, the ground size of the FOV, and the smoothness of spatial response functions. Explicit consideration of the spatial response function is favorable for fine-grid oversampling and smoother spatial response. For OMI, it is beneficial to oversample using the spatial response functions for grids finer than ∼16 km. The generalized 2-D super Gaussian function also enables smoothing of the level 3 results by decreasing the shape-determining exponents, which is useful for a high noise level or sparse satellite datasets. This physical oversampling approach is especially advantageous during smaller temporal windows and shows substantially improved visualization of trace gas distribution and local gradients when applied to OMI NO2 products and IASI NH3 products. There is no appreciable difference in the computational time when using the physical oversampling versus other oversampling methods.
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Manahilov, V. "Multiphasic Spatial Response to Flickering Stimuli." Perception 26, no. 1_suppl (August 1997): 255. http://dx.doi.org/10.1068/v970259.

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If it is assumed that the weighting function of early vision can be described by a spatiotemporal Gabor-like function (Manahilov, 1995 Vision Research35 227 – 237), the spatial impulse response to flickering stimuli would consist of more alternating phases than that to a brief stimulus. To test this prediction, the Westheimer paradigm and the brightness matching technique were used. The effect of a flickering inducing disk (temporal frequency 7.7 Hz, duration 195 ms, zero starting phase) of variable radius on the apparent brightness of an incremental test stimulus (1.2 min arc radius, duration 14.25 ms) was measured in foveal photopic vision. The test stimulus was superimposed on the centre of the inducing disk and presented 142 ms after the onset of the inducing stimulus. When the radius of the inducing stimulus was increased, the test brightness was enhanced, reaching a maximum at a radius of 3 min arc, then diminished below the control level at radii of 9 – 11 min arc and was enhanced again at radii of 14 – 17 min arc. This finding differed from the unimodal effect of a brief inducing disk on test brightness and suggested a multiphasic profile of the spatial impulse response to a flickering stimulus. This suggestion was supported by the dependence of the apparent brightness of a test line on the distance between the test and two flanking inducing lines. The temporal conditions were similar to those of the previous experiment. The brightness of the test line was increased above the control level at distances of 0 – 2 min arc, decreased at distances of 3 – 6 min arc and again increased to a smaller extent at distances of 10 – 13 min arc. Brief inducing lines evoked only the initial enhancement of the test-line brightness and its decrease at lateral positions. The data obtained are in line with the predictions of the model of the visual weighting function.
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Tong, Lillian, William Guido, Nina Tumosa, Peter D. Spear, and Susan Heidenreich. "Binocular interactions in the cat's dorsal lateral geniculate nucleus, II: Effects on dominant-eye spatial-frequency and contrast processing." Visual Neuroscience 8, no. 6 (June 1992): 557–66. http://dx.doi.org/10.1017/s0952523800005654.

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AbstractThe present study tested the hypothesis that nondominant-eye influences on lateral geniculate nucleus (LGN) neurons affect the processing of spatial and contrast information from the dominant eye. To do this, we determined the effects of stimulating the nondominant eye at its optimal spatial frequency on the responses of LGN cells to sine-wave gratings of different spatial frequency and contrast presented to the dominant eye. Detailed testing was carried out on 49 cells that had statistically significant responses to stimulation of the nondominant eye alone.Spatial-frequency response functions to nondominant-eye stimulation indicated that the responses were spatially tuned, as reported previously (Guido et al., 1989). Optimal spatial frequencies through the nondominant eye were significantly correlated with the optimal spatial frequencies through the dominant eye (r = 0.54; P < 0.0001), and the optimal spatial frequencies were fairly similar for the two eyes.Nondominant-eye stimulation changed the maximal amplitude of the fundamental (Fl) response to dominant-eye stimulation for only about 45% (22 of 49) of the cells that responded to nondominant-eye stimulation alone. The response vs. contrast function through the dominant eye was altered for 73% of the cells (51% independent of spatial frequency). Three types of effects were observed: a change in the initial slope of the response vs. contrast function (contrast gain), a change in the response amplitude at which saturation occurred, or an overall change in response at all contrasts. The incidence of these changes was similar for X and Y cells in LGN layers A, Al, and C (only four W cells were tested).Nondominant-eye stimulation had little or no effect on the sizes or sensitivities of the receptive-field centers or surrounds for the dominant eye. In addition, nondominant-eye stimulation had little or no effect on optimal spatial frequency, spatial resolution, or the bandwidth of spatial-frequency contrast sensitivity curves for the dominant eye.Possible functions of binocular interactions in the LGN are considered. The present results suggest a role in interocular contrast-gain control. Interocular contrast differences can occur before the acquisition of binocular fusion, when the two eyes are viewing different aspects of a visual stimulus. Psychophysical and physiological studies suggest that an interocular mechanism exists to maintain relatively constant binocular interactions despite differences in interocular contrast. The present results suggest that at least part of this mechanism occurs in the LGN.
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Pouget, Alexandre, and Terrence J. Sejnowski. "Spatial Transformations in the Parietal Cortex Using Basis Functions." Journal of Cognitive Neuroscience 9, no. 2 (March 1997): 222–37. http://dx.doi.org/10.1162/jocn.1997.9.2.222.

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Sensorimotor transformations are nonlinear mappings of sensory inputs to motor responses. We explore here the possibility that the responses of single neurons in the parietal cortex serve as basis functions for these transformations. Basis function decomposition is a general method for approximating nonlinear functions that is computationally efficient and well suited for adaptive modification. In particular, the responses of single parietal neurons can be approximated by the product of a Gaussian function of retinal location and a sigmoid function of eye position, called a gain field. A large set of such functions forms a basis set that can be used to perform an arbitrary motor response through a direct projection. We compare this hypothesis with other approaches that are commonly used to model population codes, such as computational maps and vectorial representations. Neither of these alternatives can fully account for the responses of parietal neurons, and they are computationally less efficient for nonlinear transformations. Basis functions also have the advantage of not depending on any coordinate system or reference frame. As a consequence, the position of an object can be represented in multiple reference frames simultaneously, a property consistent with the behavior of hemineglect patients with lesions in the parietal cortex.
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Dissertations / Theses on the topic "Spatial response function"

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Niedfeldt, John Clyde. "RapidSCAT Slice Spatial Response Function Contour Parameterization." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6260.

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The spatial response function (SRF) of the backscatter measurements for a radar scatterometer is often used in reconstruction. It has been found that in many cases the SRF can be approximated as a binary function that is 1 inside the - 6 dB contour of the SRF and 0 outside. This improves the computation speed of reconstruction. Computing the SRF contour can still be a lengthy computation, which can be simplified by precomputing and tabulating key SRF contours. The tabular parameterization for many spinning scatterometers, i.e., QuikSCAT, is straight-forward. For RapidSCAT, this estimation is more involved than other radars due to the irregular orbit of its host platform, the International Space Station (ISS). This thesis presents a process for parameterizing the slice contours for RapidSCAT that are acceptable for reconstruction purposes. This thesis develops a new process for parameterizing slice contours. First, RapidSCAT SRFs are calculated using XfactorRS3, and -6 dB slice contours are found using matplotlib. Then, a suitable filter is found for reducing noise present in slice contours due to quantization error and interpolation inaccuracies. Afterwards, the polygon comparison algorithm is used to determine a set of approximation points. With the approximation points selected, the 3-rd order linear approximation is calculated using parameters available in the L1B data files for RapidSCAT. Finally, analysis of the parameterization is performed. Overall, I developed a process that parameterizes RapidSCAT slice contours with an average root mean square (RMS) error of roughly 1.5 km. This is acceptable for the application of the slice parameterization algorithm and significantly reduces computation compared to fully computing the SRF.
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Bury, Samuel Gary. "The Estimation of the RapidScat Spatial Response Function." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6797.

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RapidScat is a pencil-beam wind scatterometer which operated from September 2014 to August 2016. Mounted aboard the International Space Station (ISS), RapidScat experiences significant altitude and attitude variations over its dataset. These variations need to be properly accounted for to ensure accurate calibration and to produce high resolution scatterometer images. Both the antenna pose and the one-way antenna pattern need to be validated. The spatial response function (SRF) is the two-way antenna pattern for a scatterometer combined with the processing and filtering done in the radar system electronics, and is dominated by the two-way pattern. To verify the pointing of the RapidScat antenna, the RapidScat SRF is estimated using on-orbit data. A rank reduced least squares estimate is used, which was developed previously for the Oceansat-2 (OSCAT) scatterometer [1]. This algorithm uses a small, isolated island as a delta function to sample the SRF. The island used is Rarotonga Island of the Cook Islands. The previously developed algorithm is updated to estimate the SRF in terms of beam azimuth and elevation angle rather than in kilometers on the ground. The angle-based coordinate system promotes greater understanding of how the SRF responds to biases and errors in antenna geometry. The estimation process is simulated to verify its accuracy by calculating the SRF for several thousand measurements in the region of Rarotonga. The calculated SRFs are multiplied by a corresponding synthetically created surface and integrated to yield simulated backscatter measurements, with added white noise. The SRF estimation algorithm is then performed. The results of the simulation show that the SRF estimation process yields a close estimate of the original SRF. The antenna pointing is validated by introducing a fixed offset in azimuth angle into the simulation and observing that the SRF is correspondingly shifted in the azimuth-elevation grid. The SRF computed from real data shows that there is an azimuth rotation angle bias of about 0.263 degrees for the inner beam and about 0.244 degrees for the outer beam. Since the SRF is dominated by the two-way antenna pattern, it can be modeled as the product of two identical one-way antenna patterns which are slightly offset from each other due to antenna rotation during the transmit/receive cycle. A method is developed based on this model to derive the one-way antenna pattern from the estimated SRF. Using a Taylor series expansion the one-way antenna pattern is computed from the SRF. The derived pattern recovers the SRF with small error, but there is significant error in the inferred one-way pattern when compared to the pre-launch estimated RapidScat one-way antenna pattern.
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Kim, Youngtae. "Spatial resolution limits for the reconstruction of acoustic source distribution by inverse techniques." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274706.

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Lindsley, Richard D. "Enhanced-Resolution Processing and Applications of the ASCAT Scatterometer." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5739.

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The ASCAT scatterometer measures the Earth surface microwave radar backscatter in order to estimate the near-surface winds over the oceans. While the spatial resolution of the conventional applications is sufficient for many purposes, other geoscience applications benefit from an improved spatial resolution. Specialized algorithms may be applied to the scatterometer data in order to reconstruct the radar backscatter on a high-resolution grid. Image reconstruction requires the spatial response function (SRF) of each measurement, which is not reported with the measurement data. To address this need, I precisely model the SRF incorporating (1) the antenna beam response, (2) the processing performed onboard ASCAT before telemetering to the ground, and (3) the Doppler shift induced by a satellite orbiting the rotating Earth. I also develop a simple parameterized model of the SRF to reduce computational complexity. The accuracy of both models is validated.Image reconstruction of the ASCAT data is performed using the modeled SRF. I discuss the spatial resolution of the reconstructed ASCAT images and consider the first- and second-order statistics of the reconstructed data. Optimum values for the parameters of the reconstruction algorithms are also considered. The reconstructed radar backscatter data may be used for enhanced-resolution wind retrieval and for geoscience applications. In this dissertation, the reconstructed backscatter data is used to map the surface extent of the 2010 Deepwater Horizon oil spill and in a study to quantify the azimuth angle anisotropy of backscatter in East Antarctica. Near-coastal ocean wind retrieval is also explored in this dissertation. Because near-coastal ocean measurements of backscatter may be “contaminated” from nearby land and introduce errors to wind retrieval, they must be discarded. The modeled SRF is used to quantify the land contamination, enabling enhanced-resolution wind retrieval much closer to the coasts. The near-coastal winds are validated against buoy measurements.
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Bradley, Joshua P. "Extending the QuikSCAT Data Record with the Oceansat-2 Scatterometer." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3435.

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Originally designed for wind velocity estimation over the ocean, scatterometers have since been applied to climate studies of the Earth's cryosphere and bioshere. As an integral part of climatological studies of the planet, the NASA Scatterometer Climate Record Pathfinder (SCP) supplies scatterometer-based products designed to aid researchers in climatological studies of the planet. In this thesis, necessary steps are taken to facilitate data from the Oceansat-2 Ku-band scatterometer (OSCAT) to be used in extending the Ku-band SCP dataset of conically scanning pencil-beam scatterometers begun by the Seawinds scatterometer flown on the QuikSCAT mission 1999-2009. As a standard SCP product, a temporal resolution enhancement technique for the scatterometer image reconstruction (SIR) algorithm is applied to OSCAT data. A relative cross-calibration method is developed to ensure consistency amongst datasets of conically scanning pencil-beam scatterometers in the SCP data time series. By application of the method, both raw data and SIR image data of OSCAT is cross-calibrated with QuikSCAT. To enable creation of SCP products requiring knowledge of the spatial response function (SRF) with OSCAT data, a method of estimating the SRF of pencil-beam scatterometers is developed. The estimation method employs rank-reduced least-squares to invert the radar equation using measurements over islands. A simulation is performed to validate the efficacy of the method and provide optimum choice of island size and number of singular values used in rank-reduced least-squares. The utility of the SRF estimates is demonstrated by applying an estimate of the OSCAT SRF to SIR image construction with OSCAT data.
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Foster, Collin David. "Spatial parameter estimation using measured frequency response functions." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314556.

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Kornak, John. "Bayesian spatial inference from haemodynamic response parameters in functional magnetic resonance imaging." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325718.

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Rincon, Rueda Diego Fernando. "Delphastus catalinae and the silverleaf whitefly, Bemisia tabaci biotype B, on tomato: modeling predation across spatial scales." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429788087.

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Rau, Christian, and rau@maths anu edu au. "Curve Estimation and Signal Discrimination in Spatial Problems." The Australian National University. School of Mathematical Sciences, 2003. http://thesis.anu.edu.au./public/adt-ANU20031215.163519.

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In many instances arising prominently, but not exclusively, in imaging problems, it is important to condense the salient information so as to obtain a low-dimensional approximant of the data. This thesis is concerned with two basic situations which call for such a dimension reduction. The first of these is the statistical recovery of smooth edges in regression and density surfaces. The edges are understood to be contiguous curves, although they are allowed to meander almost arbitrarily through the plane, and may even split at a finite number of points to yield an edge graph. A novel locally-parametric nonparametric method is proposed which enjoys the benefit of being relatively easy to implement via a `tracking' approach. These topics are discussed in Chapters 2 and 3, with pertaining background material being given in the Appendix. In Chapter 4 we construct concomitant confidence bands for this estimator, which have asymptotically correct coverage probability. The construction can be likened to only a few existing approaches, and may thus be considered as our main contribution. ¶ Chapter 5 discusses numerical issues pertaining to the edge and confidence band estimators of Chapters 2-4. Connections are drawn to popular topics which originated in the fields of computer vision and signal processing, and which surround edge detection. These connections are exploited so as to obtain greater robustness of the likelihood estimator, such as with the presence of sharp corners. ¶ Chapter 6 addresses a dimension reduction problem for spatial data where the ultimate objective of the analysis is the discrimination of these data into one of a few pre-specified groups. In the dimension reduction step, an instrumental role is played by the recently developed methodology of functional data analysis. Relatively standar non-linear image processing techniques, as well as wavelet shrinkage, are used prior to this step. A case study for remotely-sensed navigation radar data exemplifies the methodology of Chapter 6.
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Garris, Heath William. "Restructuring of Wetland Communities in Response to a Changing Climate at Multiple Spatial and Taxonomic Scales." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1383312022.

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Books on the topic "Spatial response function"

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Schelbert, Heinrich R. Image-Based Measurements of Myocardial Blood Flow. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199392094.003.0024.

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Image-based measurements of myocardial blood flow afford the assessment of coronary circulatory function. They reflect functional consequences of coronary stenoses, diffuse epicardial vessel disease and microvascular dysfunction and structural changes and thus provide a measure of the total ischemic burden. Measured flows contain therefore clinically important predictive information. Fundamental to flow measurements are the tissue tracer kinetics, their description through tracer kinetic models, high spatial and temporal resolution imaging devices and accurate extraction of radiotracer tissue concentrations from dynamically acquired images for estimating true flows from the tissue time activity curves. A large body of literature on measurements of myocardial blood flow exists for defining in humans normal values for flow at baseline and during hyperemic stress as well as for the myocardial flow reserve. The role of PET for flow measurements has been well established; initial results with modern SPECT devices are encouraging. Responses of myocardial blood flow to specific challenges like pharmacologic vasodilation and to sympathetic stimulation can uncover functional consequences of focal epicardial coronary stenoses, of conduit vessel disturbances and disease and impairments of microvascular function. Apart from risk stratification, flow measurements may allow detection of early preclinical disease, influence treatment strategies and identify therapy responses.
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and, Bruno. Attention and Learning. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198725022.003.0009.

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Attention can be defined as a multifaceted gateway to consciousness. We use attention to focus on specific sensory signals (selective attention), to allocate resources to concurrent relevant sources (divided attention), to switch between tasks (alternate attention), to maintain focus on a task for a prolonged period (sustained attention), to ready ourselves for a quick response to sudden novel information (alertness); and all these processes, to some extent, control what sensory signals are processed up to the level of conscious awareness. The multifarious functions of attention often involve multisensory interactions, and in this chapter, will we discuss three broad issues in studying multisensory attention. We will start by considering multisensory spatial attention to signals within different sensory channels in a goal directed manner, in comparison to conditions whereby attention is automatically engaged by external multisensory signals. Next, we will discuss multisensory non-spatial attention. In conclusion, we will discuss the implications for multisensory learning and memory.
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Narayana, Shalini, Felipe Salinas, Frederick A. Boop, James W. Wheless, and Andrew C. Papanicolaou. Transcranial Magnetic Stimulation. Edited by Andrew C. Papanicolaou. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199764228.013.11.

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Transcranial magnetic stimulation (TMS) is used to study cortical function by applying localized magnetic fields in a noninvasive manner. This chapter reviews the basic principles of TMS, including the stimulator unit, coils, and the interaction of TMS-induced electric field with the cortex. The advantages of TMS over invasive brain mapping techniques are highlighted. Improvements in the spatial accuracy of TMS are described in the context of image-guided TMS. Types of responses induced by motor cortex stimulation and their utility in mapping normal and diseased motor cortex are discussed. Language mapping with TMS takes advantage of the TMS-induced transient disruption of function, also termed “virtual lesion.” The authors provide examples of successful application of TMS in presurgical mapping of the motor and language areas in the brain. Emerging applications of TMS in the diagnosis of neuropsychiatric disorders and safety of TMS are also discussed.
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May, Robert, and Angela R. McLean, eds. Theoretical Ecology. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199209989.001.0001.

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Robert May's seminal book has played a central role in the development of ecological science. Originally published in 1976, this influential text has overseen the transition of ecology from an observational and descriptive subject to one with a solid conceptual core. Indeed, it is a testament to its influence that a great deal of the novel material presented in the earlier editions has now been incorporated into standard undergraduate textbooks. It is now a quarter of a century since the publication of the second edition, and a thorough revision is timely. Theoretical Ecology provides a succinct, up-to-date overview of the field set in the context of applications, thereby bridging the traditional division of theory and practice. It describes the recent advances in our understanding of how interacting populations of plants and animals change over time and space, in response to natural or human-created disturbance. In an integrated way, initial chapters give an account of the basic principles governing the structure, function, and temporal and spatial dynamics of populations and communities of plants and animals. Later chapters outline applications of these ideas to practical issues including fisheries, infectious diseases, tomorrow's food supplies, climate change, and conservation biology. Throughout the book, emphasis is placed on questions which as yet remain unanswered. The editors have invited the top scientists in the field to collaborate with the next generation of theoretical ecologists. The result is an accessible, advanced textbook suitable for senior undergraduate and graduate level students as well as researchers in the fields of ecology, mathematical biology, environmental and resources management. It will also be of interest to the general reader seeking a better understanding of a range of global environmental problems.
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Book chapters on the topic "Spatial response function"

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Neagu, Monica, and Carolina Constantin. "Signal Transduction in Immune Cells and Protein Kinases." In Advances in Experimental Medicine and Biology, 133–49. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-49844-3_5.

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AbstractImmune response relies upon several intracellular signaling events. Among the protein kinases involved in these pathways, members of the protein kinase C (PKC) family are prominent molecules because they have the capacity to acutely and reversibly modulate effector protein functions, controlling both spatial distribution and dynamic properties of the signals. Different PKC isoforms are involved in distinct signaling pathways, with selective functions in a cell-specific manner.In innate system, Toll-like receptor signaling is the main molecular event triggering effector functions. Various isoforms of PKC can be common to different TLRs, while some of them are specific for a certain type of TLR. Protein kinases involvement in innate immune cells are presented within the chapter emphasizing their coordination in many aspects of immune cell function and, as important players in immune regulation.In adaptive immunity T-cell receptor and B-cell receptor signaling are the main intracellular pathways involved in seminal immune specific cellular events. Activation through TCR and BCR can have common intracellular pathways while others can be specific for the type of receptor involved or for the specific function triggered. Various PKC isoforms involvement in TCR and BCR Intracellular signaling will be presented as positive and negative regulators of the immune response events triggered in adaptive immunity.
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Pedersen, Michael, Pietro Irrera, Walter Dastrù, Frank G. Zöllner, Kevin M. Bennett, Scott C. Beeman, G. Larry Bretthorst, Joel R. Garbow, and Dario Livio Longo. "Dynamic Contrast Enhancement (DCE) MRI–Derived Renal Perfusion and Filtration: Basic Concepts." In Methods in Molecular Biology, 205–27. New York, NY: Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-0978-1_12.

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AbstractDynamic contrast-enhanced (DCE) MRI monitors the transit of contrast agents, typically gadolinium chelates, through the intrarenal regions, the renal cortex, the medulla, and the collecting system. In this way, DCE-MRI reveals the renal uptake and excretion of the contrast agent. An optimal DCE-MRI acquisition protocol involves finding a good compromise between whole-kidney coverage (i.e., 3D imaging), spatial and temporal resolution, and contrast resolution. By analyzing the enhancement of the renal tissues as a function of time, one can determine indirect measures of clinically important single-kidney parameters as the renal blood flow, glomerular filtration rate, and intrarenal blood volumes. Gadolinium-containing contrast agents may be nephrotoxic in patients suffering from severe renal dysfunction, but otherwise DCE-MRI is clearly useful for diagnosis of renal functions and for assessing treatment response and posttransplant rejection.Here we introduce the concept of renal DCE-MRI, describe the existing methods, and provide an overview of preclinical DCE-MRI applications to illustrate the utility of this technique to measure renal perfusion and glomerular filtration rate in animal models.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction is complemented by two separate publications describing the experimental procedure and data analysis.
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Xie, Minge, Douglas G. Simpson, and Raymond J. Carroll. "Scaled Link Functions for Heterogeneous Ordinal Response Data*." In Modelling Longitudinal and Spatially Correlated Data, 23–36. New York, NY: Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-0699-6_3.

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Lin, Fa-Hsuan, Thomas Witzel, Matti S. Hämäläinen, and Aapo Nummenmaa. "Combining Noninvasive Electromagnetic and Hemodynamic Measures of Human Brain Activity." In Brain and Human Body Modeling 2020, 179–93. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_10.

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AbstractMagnetoencephalography (MEG) is directly sensitive to postsynaptic neuronal activity with the millisecond temporal resolution. MEG is ideally to complement functional MRI (fMRI), which measures hemodynamic responses secondary to neuronal activity with the millimeter spatial resolution, for noninvasive imaging of human brain function. Here, using the Minimum-Norm Estimate as an example, we review how fMRI can be integrated with MEG (and electroencephalography, EEG) source modeling and summarize potential advantages and pitfalls of this data fusion technique. Neurovascular coupling as the physiological basis for MEG/EEG/fMRI integration is also discussed. Ultimately, we expect to develop multimodal MEG/EEG/fMRI neuroimaging methodology for characterizing spatiotemporal functional connectivity in large-scale neural networks of the human brain with high sensitivity and accuracy.
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Tur, Carmen, Francesco Grussu, Ferran Prados, Sara Collorone, Claudia A. M. Gandini Wheeler-Kingshott, and Olga Ciccarelli. "Spatial Characterisation of Fibre Response Functions for Spherical Deconvolution in Multiple Sclerosis." In Computational Diffusion MRI, 265–79. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05831-9_21.

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Ewert, J. P. "Neuroethology: Toward a Functional Analysis of Stimulus-Response Mediating and Modulating Neural Circuitries." In Cognitive Processes and Spatial Orientation in Animal and Man, 177–200. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3531-0_16.

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Wang, Jiaping, Hongtu Zhu, Jianqing Fan, Kelly Giovanello, and Weili Lin. "Adaptively and Spatially Estimating the Hemodynamic Response Functions in fMRI." In Lecture Notes in Computer Science, 269–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23629-7_33.

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Baier, Daniel, and Wolfgang Polasek. "Marketing and Regional Sales: Evaluation of Expenditure Strategies by Spatial Sales Response Functions." In Studies in Classification, Data Analysis, and Knowledge Organization, 673–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-10745-0_74.

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Zyśk, Janusz, Artur Wyrwa, and Beata Sliz-Szkliniarz. "Spatially Disaggregated Impact Pathway Analysis of Direct Particulate Matter Emissions." In The Future European Energy System, 275–89. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-60914-6_15.

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AbstractThis chapter focuses on the evaluation of air quality and health impacts associated with direct emissions of air pollutants for different REFLEX scenarios based on the Driver-Pressure-State-Impact-Response framework. Ambient concentration of air pollutants is calculated with the use of the Polyphemus Air Quality System. Health impacts are calculated using the concentration-response functions. Results show that particulate matter emissions in Europe will decrease by 10 times till 2050. Also ambient pollutants concentrations decrease in 2050 in all REFLEX scenarios. This leads to the reduction of external costs of almost 20 billion EUR per year.
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Bowman, William D., and Melany C. Fisk. "Primary Production." In Structure and Function of an Alpine Ecosystem. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195117288.003.0016.

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The production of biomass by plants is of central importance to energy, carbon, and nutrient fluxes in ecosystems. Knowledge of the spatial and temporal variation of production and the underlying biotic and physical controls on this variation are central themes in ecosystem science. The goals of this chapter are to present the estimates of spatial patterns in above- and belowground production associated with the major community types found on Niwot Ridge and other alpine areas of the southern Rocky Mountains and to examine the likely environmental causes and underlying mechanisms responsible for spatial and temporal variation in production as elucidated by experimental and observational studies. Rates of primary production and standing crops of plant biomass are low in alpine tundra relative to other ecosystem types (Lieth and Whittaker 1975; Zak et al. 1994). However, within communities (i.e., at the plot level), there is large variation in rates of production, the degree of biotic control over response to environmental change, and the principal environmental constraints of primary production. As a result, the alpine is one of the most dynamic ecosystems for research. For example, there is a tenfold difference in annual aboveground production between the most and least productive sites with continuous plant cover on Niwot Ridge. In addition, the high plant diversity is a source of potential variation in physiological and developmental control of plant response to the environment. Dominant species include sedges, grasses, shrubs, and forbs, among which are N2-fixing Trifolium species. Nearly all of the dominant species may be mycorrhizal. Soil moisture, a driving force for many biotic processes, may vary by an order of magnitude between wet and dry sites following prolonged periods of drought. Thus the alpine tundra of Niwot Ridge, which might appear superficially homogeneous, in fact has complex physical and biotic gradients. This spatial variation prevents simple generalizations about single limiting resources or climatic driving forces determining spatial and temporal variation in productivity. Billings (1973) defined the mesotopographic gradient as a working unit for describing the alpine landscape, as it encompasses the full range of snow accumulation and associated microclimates and thus biological diversity.
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Conference papers on the topic "Spatial response function"

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Ashcraft, Ivan S., and David G. Long. "The spatial response function of SeaWinds backscatter measurements." In Optical Science and Technology, SPIE's 48th Annual Meeting, edited by William L. Barnes. SPIE, 2003. http://dx.doi.org/10.1117/12.506255.

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Mitchell, Toby J., and Max D. Morris. "The spatial correlation function approach to response surface estimation." In the 24th conference. New York, New York, USA: ACM Press, 1992. http://dx.doi.org/10.1145/167293.167638.

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Kasahara, Naoto, and Hideki Takasho. "Stress Response Functions to Multi-Dimensional Spatial Fluctuations of Fluid Temperature." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1327.

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Temperature fluctuation from incomplete fluid mixing induces fatigue damages on structures of nuclear components, which should be prevented. For rational analyses of this phenomenon, the authors have developed a frequency response function of thermal stress and extended to multi-dimensional spatial fluctuations of fluid temperature. This function is formulated by a product of the effective heat transfer and the effective thermal stress functions, and enables us to quickly calculate the thermal stresses induced by both local and global temperature distributions in structures. Furthermore, it can evaluate sensitivities of thermal stress to frequencies of temperature fluctuation, Biot number and constraint conditions of structures. Applicability of this function was verified for multi-dimensional problems such as thermal stratification problems and hot/cold spot ones.
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Heredia Conde, Miguel, Klaus Hartmann, and Otmar Loffeld. "Crosstalk characterization of PMD pixels using the spatial response function at subpixel level." In IS&T/SPIE Electronic Imaging, edited by Robert Sitnik and William Puech. SPIE, 2015. http://dx.doi.org/10.1117/12.2083353.

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Wynn, Logan T., Andrew Truitt, Isaac Heim, and S. Nima Mahmoodi. "Modeling and Response Analysis of Piezoelectric Flag in Wind Flow." In ASME 2013 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/dscc2013-3912.

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Within the past decade, research in the piezoelectric energy harvesting field has grown significantly concerning material selection, device configurations, and actuation methods. Oscillating cantilevered piezoelectric energy harvesters are one of the more common designs. The flag is modeled as a cantilevered Euler-Bernoulli beam with a low modulus of elasticity, and the representative equation for this is broadly accepted. The wind pressure is modeled by a method that is apparently well accepted in the aerospace field. Among other modeling assumptions, the partial differential equation is considered separable. Once separated, the spatial equation is adjusted using an auxiliary function in order to determine the mode shapes. With the mode shapes characterized, the time function is rendered, which can yield representations for either a damped or undamped system. Individually, these time functions are combined with the adjusted spatial function using the Galerkin method. Plotted results represent the periodic, two-dimensional system response over time.
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Park, Duk-Hyun, and Bingen Yang. "Static and Dynamic Response of Plates With Curved Boundaries." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4078.

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Abstract A semi-analytical method for analysis of flexible plates with curved boundaries is presented. Through an isoparametric transformation, the original spatial domain of the plate is mapped onto a rectangular region, where the strip distributed transfer functions of the plates are introduced. This transfer function formulation yields closed-form predictions of the displacement, stresses and eigensolutions of the plate. The accuracy and efficiency of the method is verified in numerical examples.
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Hoa, Luong Nguyen Hoang, Le Danh Cuong, and Luong Chinh Ke. "Enhanced spatial resolution for VNREDSat-1 multispectral images using IHS fusion technique based on sensor spectral response function." In 2016 Eighth International Conference on Knowledge and Systems Engineering (KSE). IEEE, 2016. http://dx.doi.org/10.1109/kse.2016.7758071.

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Campa, Giovanni, Sergio Mario Camporeale, Ezio Cosatto, and Giulio Mori. "Thermoacoustic Analysis of Combustion Instability Through a Distributed Flame Response Function." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68243.

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Modern gas turbines equipped with lean premixed dry low emission combustion systems suffer the problem of thermoacoustic combustion instability. The acoustic characteristics of the combustion chamber and of the burners, as well as the response of the flame to the fluctuations of pressure and equivalence ratio, exert a fundamental influence on the conditions in which the instability may occur. A three dimensional finite element code has been developed in order to solve the Helmholtz equation with a source term that models the heat release fluctuations. The code is able to identify the frequencies at which thermoacoustic instabilities are expected and the growth rate of the pressure oscillations at the onset of instability. The code is able to treat complex geometries such as annular combustion chambers equipped with several burners. The adopted acoustic model is based upon the definition of the Flame Response Function (FRF) to acoustic pressure and velocity fluctuations in the burners. In this paper, data from CFD simulations are used to obtain a distribution of FRF of the κ-τ type as a function of the position within the chamber. The intensity coefficient, κ, is assumed to be proportional to the reaction rate of methane in a two-step mechanism. The time delay τ is estimated on the basis of the trajectories of the fuel particles from the injection point in the burner to the flame front. The paper shows the results obtained from the application of FRF with spatial distributions of both κ and τ. The present paper also shows the comparison between the application of the proposed model for the FRF and the traditional application of the FRF over a concentrated flame in a narrow area at the entrance to the combustion chamber. The distribution of the intensity coefficient and the time delay proves to have an influence, both on the eigenfrequency values and on the growth rates, in several of the examined modes. The proposed method is therefore able to establish a theoretical relation of the characteristics of the flame (depending on the burner geometry and operating conditions) to the onset of the thermoacoustic instability.
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Kim, J. W., and K. Kim. "Response-Based Evaluation of Design Sloshing Loads for Membrane-Type LNG Carriers." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29746.

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Sloshing model test and dynamic structural analysis of a membrane-type LNG tank is performed to determine design sloshing loads for LNG containment system. Spatial, temporal and statistical characteristics of the measured sloshing loads are investigated. Dynamic structural analysis of a LNG containment system is performed to obtain structural responses at predefined critical locations under short duration triangular pulse, which is referred to as triangular impulse response function (TIRF). The TIRFs are synthesized with time history of measured sloshing loads to obtain dynamic response of the LNG containment system. Statistical analysis of peak stress values are used as basis of determining design sloshing loads for the structural assessment of LNG containment system.
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Bobusch, Bernhard C., Bernhard Ćosić, Jonas P. Moeck, and Christian Oliver Paschereit. "Optical Measurement of Local and Global Transfer Functions for Equivalence Ratio Fluctuations in a Turbulent Swirl Flame." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95649.

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Equivalence ratio fluctuations are known to be one of the key factors controlling thermoacoustic stability in lean premixed gas turbine combustors. The mixing and thus the spatio-temporal evolution of these perturbations in the combustor flow is, however, difficult to account for in present low-order modeling approaches. To investigate this mechanism, experiments in an atmospheric combustion test rig are conducted. To assess the importance of equivalence ratio fluctuations in the present case, flame transfer functions for different injection positions are measured. By adding known perturbations in the fuel flow using a solenoid valve, the influence of equivalence ratio oscillations on the heat release rate is investigated. The spatially and temporally resolved equivalence ratio fluctuations in the reaction zone are measured using two optical chemiluminescence signals, captured with an intensified camera. A steady calibration measurement allows for the quantitative assessment of the equivalence ratio fluctuations in the flame. This information is used to obtain a mixing transfer function, which relates fluctuations in the fuel flow to corresponding fluctuations in the equivalence ratio of the flame. The current study focuses on the measurement of the global, spatially integrated, transfer function for equivalence ratio fluctuations and the corresponding modeling. In addition, the spatially resolved mixing transfer function is shown and discussed. The global mixing transfer function reveals that despite the good spatial mixing quality of the investigated generic burner, the ability to damp temporal fluctuations at low frequencies is rather poor. It is shown that the equivalence ratio fluctuations are the governing heat release rate oscillation response mechanism for this burner in the low-frequency regime. The global transfer function for equivalence ratio fluctuations derived from the measurements is characterized by a pronounced low-pass characteristic, which is in good agreement with the presented convection–diffusion mixing model.
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