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Articoli di riviste sul tema "SPECTRAL - SPATIAL STRATEGIES"
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Wefers, Stefanie, Ashish Karmacharya e Frank Boochs. "Development of a platform recommending 3D and spectral digitisation strategies". Virtual Archaeology Review 7, n. 15 (15 novembre 2016): 18. http://dx.doi.org/10.4995/var.2016.5861.
Testo completoAbstract (sommario):
<p class="VARAbstract" align="left">Spatial and spectral recording of cultural heritage objects is a complex task including data acquisition, processing and analysis involving different technical disciplines. Additionally, the development of a suitable digitisation strategy satisfying the expectations of the humanities experts needs an interdisciplinary dialogue often suffering from misunderstanding and knowledge gaps on both the technical and humanities sides.</p><p class="VARAbstract" align="left">Through a concerted discussion experts from the cultural heritage and technical domains currently develop a so-called COSCH<sup>KR</sup> platform (Colour and Space in Cultural Heritage Knowledge Representation) which will give recommendations for spatial and spectral recording strategies adapted to the needs of the cultural heritage application. The platform will make use of an ontology through which the relevant parameters of the different domains involved in the recording, processing, analysis and dissemination of cultural heritage objects are hierarchically structured and are related through rule-based dependencies. Background and basis for this ontology is the fact that a deterministic relation exists between (1) the requirements of a cultural heritage application on spatial, spectral, as well as visual digital information of a cultural heritage object which itself has concrete physical characteristics and (2) the technical possibilities of the spectral and spatial recording devices. Through a case study which deals with the deformation analysis of wooden samples of cultural heritage artefacts this deterministic relationship is illustrated explaining the overall structure and development of the ontology.</p><p class="VARAbstract" align="left">The aim of the COSCH<sup>KR</sup> platform is to support cultural heritage experts finding the best suitable recording strategy for their often unique physical cultural heritage object and research question. The platform will support them and will make them aware of the relevant parameters and limitations of the recording strategy with respect to the characteristics of the cultural heritage object, external influences, application, recording devices, and data.</p>
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Gircys, Michael, e Brian J. Ross. "Image Evolution Using 2D Power Spectra". Complexity 2019 (2 gennaio 2019): 1–21. http://dx.doi.org/10.1155/2019/7293193.
Testo completoAbstract (sommario):
Procedurally generated images and textures have been widely explored in evolutionary art. One active research direction in the field is the discovery of suitable heuristics for measuring perceived characteristics of evolved images. This is important in order to help influence the nature of evolved images and thereby evolve more meaningful and pleasing art. In this regard, particular challenges exist for quantifying aspects of style and shape. In an attempt to bridge the divide between computer vision and cognitive perception, we propose the use of measures related to image spatial frequencies. Based on existing research that uses power spectral density of spatial frequencies as an effective metric for image classification and retrieval, we posit that Fourier decomposition can be effective for guiding image evolution. We refine fitness measures based on Fourier analysis and spatial frequency and apply them within a genetic programming environment for image synthesis. We implement fitness strategies using 2D Fourier power spectra and phase, with the goal of evolving images that share spectral properties of supplied target images. Adaptations and extensions of the fitness strategies are considered for their utility in art systems. Experiments were conducted using a variety of greyscale and colour target images, spatial fitness criteria, and procedural texture languages. Results were promising, in that some target images were trivially evolved, while others were more challenging to characterize. We also observed that some evolved images which we found discordant and “uncomfortable” show a previously identified spectral phenomenon. Future research should further investigate this result, as it could extend the use of 2D power spectra in fitness evaluations to promote new aesthetic properties.
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Maurer, Hansruedi, Stewart Greenhalgh e Sabine Latzel. "Frequency and spatial sampling strategies for crosshole seismic waveform spectral inversion experiments". GEOPHYSICS 74, n. 6 (novembre 2009): WCC79—WCC89. http://dx.doi.org/10.1190/1.3157252.
Testo completoAbstract (sommario):
Analyses of synthetic frequency-domain acoustic waveform data provide new insights into the design and imaging capability of crosshole surveys. The full complex Fourier spectral data offer significantly more information than other data representations such as the amplitude, phase, or Hartley spectrum. Extensive eigenvalue analyses are used for further inspection of the information content offered by the seismic data. The goodness of different experimental configurations is investigated by varying the choice of (1) the frequencies, (2) the source and receiver spacings along the boreholes, and (3) the borehole separation. With only a few carefully chosen frequencies, a similar amount of information can be extracted from the seismic data as can be extracted with a much larger suite of equally spaced frequencies. Optimized data sets should include at least one very low frequencycomponent. The remaining frequencies should be chosen fromthe upper end of the spectrum available. This strategy proved to be applicable to a simple homogeneous and a very complex velocity model. Further tests are required, but it appears on the available evidence to be model independent. Source and receiver spacings also have an effect on the goodness of an experimental setup, but there are only minor benefits to denser sampling when the increment is much smaller than the shortest wavelength included in a data set. If the borehole separation becomes unfavorably large, the information content of the data is degraded, even when many frequencies and small source and receiver spacings are considered. The findings are based on eigenvalue analyses using the true velocity models. Because under realistic conditions the true model is not known, it is shown that the optimized data sets are sufficiently robust to allow the iterative inversion schemes to converge to the global minimum. This is demonstrated by means of tomographic inversions of several optimized data sets.
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Huang, Leping, Zhongwen Hu, Xin Luo, Qian Zhang, Jingzhe Wang e Guofeng Wu. "Stepwise Fusion of Hyperspectral, Multispectral and Panchromatic Images with Spectral Grouping Strategy: A Comparative Study Using GF5 and GF1 Images". Remote Sensing 14, n. 4 (20 febbraio 2022): 1021. http://dx.doi.org/10.3390/rs14041021.
Testo completoAbstract (sommario):
Since hyperspectral satellite images (HSIs) usually hold low spatial resolution, improving the spatial resolution of hyperspectral imaging (HSI) is an effective solution to explore its potential for remote sensing applications, such as land cover mapping over urban and coastal areas. The fusion of HSIs with high spatial resolution multispectral images (MSIs) and panchromatic (PAN) images could be a solution. To address the challenging work of fusing HSIs, MSIs and PAN images, a novel easy-to-implement stepwise fusion approach was proposed in this study. The fusion of HSIs and MSIs was decomposed into a set of simple image fusion tasks through spectral grouping strategy. HSI, MSI and PAN images were fused step by step using existing image fusion algorithms. According to different fusion order, two strategies ((HSI+MSI)+PAN and HSI+(MSI+PAN)) were proposed. Using simulated and real Gaofen-5 (GF-5) HSI, MSI and PAN images from the Gaofen-1 (GF-1) PMS sensor as experimental data, we compared the proposed stepwise fusion strategies with the traditional fusion strategy (HSI+PAN), and compared the performances of six fusion algorithms under three fusion strategies. We comprehensively evaluated the fused results through three aspects: spectral fidelity, spatial fidelity and computation efficiency evaluation. The results showed that (1) the spectral fidelity of the fused images obtained by stepwise fusion strategies was better than that of the traditional strategy; (2) the proposed stepwise strategies performed better or comparable spatial fidelity than traditional strategy; (3) the stepwise strategy did not significantly increase the time complexity compared to the traditional strategy; and (4) we also provide suggestions for selecting image fusion algorithms using the proposed strategy. The study provided us with a reference for the selection of fusion strategies and algorithms in different application scenarios, and also provided an easy-to-implement solution and useful references for fusing HSI, MSI and PAN images.
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Zheng, Cao, Lv e Benediktsson. "Spatial–Spectral Feature Fusion Coupled with Multi-Scale Segmentation Voting Decision for Detecting Land Cover Change with VHR Remote Sensing Images". Remote Sensing 11, n. 16 (14 agosto 2019): 1903. http://dx.doi.org/10.3390/rs11161903.
Testo completoAbstract (sommario):
In this article, a novel approach for land cover change detection (LCCD) using very high resolution (VHR) remote sensing images based on spatial–spectral feature fusion and multi-scale segmentation voting decision is proposed. Unlike other traditional methods that have used a single feature without post-processing on a raw detection map, the proposed approach uses spatial–spectral features and post-processing strategies to improve detecting accuracies and performance. Our proposed approach involved two stages. First, we explored the spatial features of the VHR remote sensing image to complement the insufficiency of the spectral feature, and then fused the spatial–spectral features with different strategies. Next, the Manhattan distance between the corresponding spatial–spectral feature vectors of the bi-temporal images was employed to measure the change magnitude between the bi-temporal images and generate a change magnitude image (CMI). Second, the use of the Otsu binary threshold algorithm was proposed to divide the CMI into a binary change detection map (BCDM) and a multi-scale segmentation voting decision algorithm to fuse the initial BCDMs as the final change detection map was proposed. Experiments were carried out on three pairs of bi-temporal remote sensing images with VHR remote sensing images. The results were compared with those of the state-of-the-art methods including four popular contextual-based LCCD methods and three post-processing LCCD methods. Experimental comparisons demonstrated that the proposed approach had an advantage over other state-of-the-art techniques in terms of detection accuracies and performance.
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Liang, Fan, Cheng Qian, Wei Yu, David Griffith e Nada Golmie. "Survey of Graph Neural Networks and Applications". Wireless Communications and Mobile Computing 2022 (28 luglio 2022): 1–18. http://dx.doi.org/10.1155/2022/9261537.
Testo completoAbstract (sommario):
The advance of deep learning has shown great potential in applications (speech, image, and video classification). In these applications, deep learning models are trained by datasets in Euclidean space with fixed dimensions and sequences. Nonetheless, the rapidly increasing demands on analyzing datasets in non-Euclidean space require additional research. Generally speaking, finding the relationships of elements in datasets and representing such relationships as weighted graphs consisting of vertices and edges is a viable way of analyzing datasets in non-Euclidean space. However, analyzing the weighted graph-based dataset is a challenging problem in existing deep learning models. To address this issue, graph neural networks (GNNs) leverage spectral and spatial strategies to extend and implement convolution operations in non-Euclidean space. Based on graph theory, a number of enhanced GNNs are proposed to deal with non-Euclidean datasets. In this study, we first review the artificial neural networks and GNNs. We then present ways to extend deep learning models to deal with datasets in non-Euclidean space and introduce the GNN-based approaches based on spectral and spatial strategies. Furthermore, we discuss some typical Internet of Things (IoT) applications that employ spectral and spatial convolution strategies, followed by the limitations of GNNs in the current stage.
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Chandler, Chris J., Silvia Valery Ávila-Mosqueda, Evelyn Raquel Salas-Acosta, Eden Magaña-Gallegos, Edgar Escalante Mancera, Miguel Angel Gómez Reali, Betsabé de la Barreda-Bautista et al. "Spectral Characteristics of Beached Sargassum in Response to Drying and Decay over Time". Remote Sensing 15, n. 17 (2 settembre 2023): 4336. http://dx.doi.org/10.3390/rs15174336.
Testo completoAbstract (sommario):
The bloom of pelagic Sargassum in the Atlantic Ocean has become increasingly problematic, especially when the algae have beached. A build-up of decaying beached material has damaging effects on coastal ecosystems and tourism industries. While remote sensing offers an effective tool to assess the spatial and temporal patterns of Sargassum over large spatial extents, its use so far has been limited to a broad discrimination of Sargassum species from other macroalgae and floating vegetation. Knowledge on the spatial distribution of decayed material will help to support management strategies and inform targeted removal. In this study, we aim to characterise the spectral response of fresh and decayed Sargassum and identify regions of the spectra that offer the greatest separability for the detection and classification of decayed material. We assessed the spectral response of fresh and decayed Sargassum (1) in situ on the beach and (2) in mesocosm experiments where Sargassum samples were allowed to decay over time. We found a decrease in the magnitude of reflectance, noticeably in the visible region (400–700 nm), for decayed, in contrast to fresh, Sargassum. Separability analyses also showed that most spectral bands with a wavelength > ~540 nm will be capable of discriminating between fresh and decayed material, although the near-infrared region offers the greatest degree of separability. We demonstrate, for the first time, that there are clear differences in the spectral reflectance of fresh and decayed Sargassum with potential application for remote sensing approaches.
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Gojani, Ardian B., Dávid J. Palásti, Andrea Paul, Gábor Galbács e Igor B. Gornushkin. "Analysis and Classification of Liquid Samples Using Spatial Heterodyne Raman Spectroscopy". Applied Spectroscopy 73, n. 12 (1 agosto 2019): 1409–19. http://dx.doi.org/10.1177/0003702819863847.
Testo completoAbstract (sommario):
Spatial heterodyne spectroscopy (SHS) is used for quantitative analysis and classification of liquid samples. SHS is a version of a Michelson interferometer with no moving parts and with diffraction gratings in place of mirrors. The instrument converts frequency-resolved information into a spatially resolved one and records it in the form of interferograms. The back-extraction of spectral information is done by the fast Fourier transform. A SHS instrument is constructed with the resolving power 5000 and spectral range 522–593 nm. Two original technical solutions are used as compared to previous SHS instruments: the use of a high-frequency diode-pumped solid-state laser for excitation of Raman spectra and a microscope-based collection system. Raman spectra are excited at 532 nm at the repetition rate 80 kHz. Raman shifts between 330 cm−1 and 1600 cm−1 are measured. A new application of SHS is demonstrated: for the first time, it is used for quantitative Raman analysis to determine concentrations of cyclohexane in isopropanol and glycerol in water. Two calibration strategies are employed: univariate based on the construction of a calibration plot and multivariate based on partial least squares regression. The detection limits for both cyclohexane in isopropanol and glycerol in water are at a 0.5 mass% level. In addition to the Raman–SHS chemical analysis, classification of industrial oils (biodiesel, poly(1-decene), gasoline, heavy oil IFO380, polybutenes, and lubricant) is performed using the Raman–fluorescence spectra of the oils and principal component analysis. The oils are easily discriminated showing distinct non-overlapping patterns in the principal component space.
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Sun, Jun, Junbo Zhang, Xuesong Gao, Mantao Wang, Dinghua Ou, Xiaobo Wu e Dejun Zhang. "Fusing Spatial Attention with Spectral-Channel Attention Mechanism for Hyperspectral Image Classification via Encoder–Decoder Networks". Remote Sensing 14, n. 9 (19 aprile 2022): 1968. http://dx.doi.org/10.3390/rs14091968.
Testo completoAbstract (sommario):
In recent years, convolutional neural networks (CNNs) have been widely used in hyperspectral image (HSI) classification. However, feature extraction on hyperspectral data still faces numerous challenges. Existing methods cannot extract spatial and spectral-channel contextual information in a targeted manner. In this paper, we propose an encoder–decoder network that fuses spatial attention and spectral-channel attention for HSI classification from three public HSI datasets to tackle these issues. In terms of feature information fusion, a multi-source attention mechanism including spatial and spectral-channel attention is proposed to encode the spatial and spectral multi-channels contextual information. Moreover, three fusion strategies are proposed to effectively utilize spatial and spectral-channel attention. They are direct aggregation, aggregation on feature space, and Hadamard product. In terms of network development, an encoder–decoder framework is employed for hyperspectral image classification. The encoder is a hierarchical transformer pipeline that can extract long-range context information. Both shallow local features and rich global semantic information are encoded through hierarchical feature expressions. The decoder consists of suitable upsampling, skip connection, and convolution blocks, which fuse multi-scale features efficiently. Compared with other state-of-the-art methods, our approach has greater performance in hyperspectral image classification.
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Miao, Zelang, e Wenzhong Shi. "A New Methodology for Spectral-Spatial Classification of Hyperspectral Images". Journal of Sensors 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/1538973.
Testo completoAbstract (sommario):
Recent developments in hyperspectral images have heightened the need for advanced classification methods. To reach this goal, this paper proposed an improved spectral-spatial method for hyperspectral image classification. The proposed method mainly consists of three steps. First, four band selection strategies are proposed to utilize the statistical region merging (SRM) method to segment the hyperspectral image. The segmentation map is subsequently integrated with the pixel-wise classification method to classify the hyperspectral image. Finally, the final classification result is obtained using the decision fusion rule. Validation tests are performed to evaluate the performance of the proposed approach, and the results indicate that the new proposed approach outperforms the state-of-the-art methods.
Tesi sul tema "SPECTRAL - SPATIAL STRATEGIES"
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GAKHAR, SHALINI. "DEVELOPMENT OF SPECTRAL-SPATIAL STRATEGIES FOR DETECTION OF ENGINEERED OBJECTS USING HYPERSPECTRAL DATA". Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18905.
Testo completoAbstract (sommario):
Humans all across the globe migrate to cities/urban areas in search of better livelihood. In India alone, the migrant population moving to cities is likely to rise to 40% by 2030. Urbanization takes a heavy toll of the scarce resources. Besides, there are many adverse environmental effects of rapid urbanization. Urban planners, therefore, have to continuously control and monitor the urban expansion, plan amenities, make judicious allocation of lands for industries, residences and agriculture, ensure low environmental pollution and simultaneously also address several other challenges of urban planning.
Remote sensing in general has been a very important supporting tool in the hands of urban planners in assessment of existing urban growth particularly in extraction of different levels of urban engineered surfaces such as roads and roofs etc. and its interpolation to assess future urban growth. The development in the field of remote sensing has therefore always been of interest to urban planners. The development of Hyperspectral Remote Sensing has further enabled urban planners in better assessment of urban expanse. However, though hyperspectral data is significantly more useful to the urban planners, it comes with its own set of challenges such as spectral variability, mixed pixel problems, accuracy requirements, requirement of recovery shape for correct identification of urban engineered surfaces (roads and roofs), selection of an appropriate approach such as target detection/classification/machine learning approach for information extraction providing better accuracy etc.
The present Thesis explores one of the relevant problems useful for urban planners i.e development of spectral-spatial strategies for detection of engineered objects using hyperspectral data. This problem has been explored under three
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objectives. The first objective deals with an exhaustive comparative assessment of standard spectral target detection algorithms for engineered objects using hyperspectral data, under four categories. Various algorithms reported in literature have been considered for comparison. The second objective involves, development of different strategies for detection of engineered objects. It has been performed under two sub-objectives. In the first part, spectral - spatial urban target detection using Artificial Neural Network (ANN) has been explored. The second part explores, detection of the engineered surfaces (roads and roofs) using deep learning approach. The last objective expounds mixed pixel analysis and shape identification of engineered objects using hyperspectral data. This is also done in two parts, the first part deals with extraction of urban targets using fusion of spectral and shape features, and the second part deals with urban target detection using super-resolution mapping approach by recovery of shape.
The data for the research is Airborne Visible and Infrared Imaging Spectrometer – Next Generation (AVIRIS-NG) hyperspectral data collected during a joint ISRO-NASA campaign held during 2016-2017. For the present study, urban hyperspectral data for Udaipur, Rajasthan captured during February 2016 has been used.
For comparative assessment, different categories of target detection algorithms have been considered for extraction of roads and roofs. This has been implemented using reference spectra using both the in-scene (derived from image) and in-field (collected while ground data campaign) spectra. One of the findings of the results suggests that, Mahanalobis angle measure may be one of the robust angle measures for detection of roads and roofs. Besides in general, it is found that machine learning based methods such as ANN and ELM perform better amongst all the measures.
Associating spatial information such as morphological attribute profiles along with spectral signatures of labelled pixels of targets have yielded higher accuracy as
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compared to standard target detection methods. The approach seems to perform better when targets of interests are composed of similar materials. For instance, roads and roofs are often made up of concrete, asphalt etc. and therefore purely spectra-based delineation of these two surfaces is challenging. Further, CNN based measures appear to provide higher accuracy in automated feature extraction of complex urban targets with minimal human intervention.
Spectral similarity of urban targets and coarse resolution of the sensor poses multiple challenges in their detection. Extraction of shape of urban engineered surfaces is an important part in urban planning. Therefore, two shape based features, exploiting the spatial aspect of hyperspectral data are proposed. Additionally, the shape of urban engineered surfaces (roads and roofs) is enhanced using unmixing based super resolution approach by taking the neighbouring pixels into account.
The study, however, restricts itself in terms of extraction of different levels of roads and roofs. Besides, the study does not link up with extraction of road and roof surfaces with different urban applications such as determination of road and roof conditions and aging. These and several other relevant issues may be explored in future.
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Usman, Muhammad. "Investigation, Design and Implementation of MIMO Antennas for Mobile Phones. Simulation and Measurement of MIMO Antennas for Mobile Handsets and Investigations of Channel Capacity of the Radiating Elements Using Spatial and Polarisation Diversity Strategies". Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4279.
Testo completoAbstract (sommario):
The objectives of this work were to investigate, design and implement Multiple-Input Multiple-Output (MIMO) antenna arrays for mobile phones. Several MIMO antennas were developed and tested over various wireless-communication frequency bands. The radiation performance and channel capacity of these antennas were computed and measured: the results are discussed in the context of the frequency bands of interest.
A comprehensive study of MIMO antenna configurations such as 2 × 1, 3 × 1, 2 × 2 and 3 × 3, using polarisation diversity as proposed for future mobile handsets, is presented. The channel capacity is investigated and discussed, as applying to Rayleigh fading channels with different power spectrum distributions with respect to azimuth and zenith angles. The channel capacity of 2 × 2 and 3 × 3 MIMO systems using spatial polarisation diversity is presented for different antenna designs. The presented results show that the maximum channel capacity for an antenna contained within a small volume can be reached with careful selection of the orthogonal spatial fields. The results are also compared against planar array MIMO antenna systems, in which the antenna size considered was much larger.
A 50% antenna size reduction method is explored by applying magnetic wall concept on the symmetry reference of the antenna structure. Using this method, a triple dual-band inverted-F antenna system is presented and considered for MIMO application. Means of achieving minimum coupling between the three antennas are investigated over the 2.45 GHz and 5.2 GHz bands.
A new 2 2 MIMO dual-band balanced antenna handset, intended to minimise the coupling with the handset and human body was proposed, developed and tested. The antenna coupling with the handset and human hand is reported in terms the radiation performance and the available channel capacity.
In addition, a dual-polarisation dipole antenna is proposed, intended for use as one of three collocated orthogonal antennas in a polarisation-diversity MIMO communication system. The antenna actually consists of two overlaid electric and magnetic dipoles, such that their radiation patterns are nominally identical but they are cross-polarised and hence only interact minimally.
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ʿUs̲mān, Muḥammad. "Investigation, design and implementation of MIMO antennas for mobile phones : simulation and measurement of MIMO antennas for mobile handsets and investigations of channel capacity of the radiating elements using spatial and polarisation diversity strategies". Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4279.
Testo completoAbstract (sommario):
The objectives of this work were to investigate, design and implement Multiple-Input Multiple-Output (MIMO) antenna arrays for mobile phones. Several MIMO antennas were developed and tested over various wireless-communication frequency bands. The radiation performance and channel capacity of these antennas were computed and measured: the results are discussed in the context of the frequency bands of interest. A comprehensive study of MIMO antenna configurations such as 2 × 1, 3 × 1, 2 × 2 and 3 × 3, using polarisation diversity as proposed for future mobile handsets, is presented. The channel capacity is investigated and discussed, as applying to Rayleigh fading channels with different power spectrum distributions with respect to azimuth and zenith angles. The channel capacity of 2 × 2 and 3 × 3 MIMO systems using spatial polarisation diversity is presented for different antenna designs. The presented results show that the maximum channel capacity for an antenna contained within a small volume can be reached with careful selection of the orthogonal spatial fields. The results are also compared against planar array MIMO antenna systems, in which the antenna size considered was much larger. A 50% antenna size reduction method is explored by applying magnetic wall concept on the symmetry reference of the antenna structure. Using this method, a triple dual-band inverted-F antenna system is presented and considered for MIMO application. Means of achieving minimum coupling between the three antennas are investigated over the 2.45 GHz and 5.2 GHz bands. A new 2 2 MIMO dual-band balanced antenna handset, intended to minimise the coupling with the handset and human body was proposed, developed and tested. The antenna coupling with the handset and human hand is reported in terms the radiation performance and the available channel capacity. In addition, a dual-polarisation dipole antenna is proposed, intended for use as one of three collocated orthogonal antennas in a polarisation-diversity MIMO communication system. The antenna actually consists of two overlaid electric and magnetic dipoles, such that their radiation patterns are nominally identical but they are cross-polarised and hence only interact minimally.
Libri sul tema "SPECTRAL - SPATIAL STRATEGIES"
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Peters, Joris, Nadja Pöllath e Benjamin S. Arbuckle. The emergence of livestock husbandry in Early Neolithic Anatolia. A cura di Umberto Albarella, Mauro Rizzetto, Hannah Russ, Kim Vickers e Sarah Viner-Daniels. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199686476.013.18.
Testo completoAbstract (sommario):
Analysis of spatio-temporal variation in patterns of animal exploitation helps our understanding of the transition from hunting to husbandry of Ovis, Capra, Sus, and Bos in Pre-Pottery Neolithic Anatolia (c.9500–7000 bce). Despite interaction with humans since the final Pleistocene, domestication of Sus in southeastern Anatolia is only evidenced after 8500 bce. This timing coincides with efforts to exert cultural control over Ovis, Capra, and Bos. Applying a broad methodological spectrum, it is shown that in southeastern Anatolia, the Neolithic ‘package’ was in place at the end of the ninth millennium bce, whereas in contemporaneous central Anatolia, livestock husbandry only included sheep and goat. Initially, animal management practices may have focused on a single species, but after 8000 bce, herding strategies comprised at least two species, likely a risk-reducing strategy. Conceivably, large-scale social gatherings, e.g. at Göbekli Tepe, promoted the spread of practices associated with ungulate management and domestication.
Capitoli di libri sul tema "SPECTRAL - SPATIAL STRATEGIES"
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Schürmann, Felix, Jean-Denis Courcol e Srikanth Ramaswamy. "Computational Concepts for Reconstructing and Simulating Brain Tissue". In Advances in Experimental Medicine and Biology, 237–59. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-89439-9_10.
Testo completoAbstract (sommario):
AbstractIt has previously been shown that it is possible to derive a new class of biophysically detailed brain tissue models when one computationally analyzes and exploits the interdependencies or the multi-modal and multi-scale organization of the brain. These reconstructions, sometimes referred to as digital twins, enable a spectrum of scientific investigations. Building such models has become possible because of increase in quantitative data but also advances in computational capabilities, algorithmic and methodological innovations. This chapter presents the computational science concepts that provide the foundation to the data-driven approach to reconstructing and simulating brain tissue as developed by the EPFL Blue Brain Project, which was originally applied to neocortical microcircuitry and extended to other brain regions. Accordingly, the chapter covers aspects such as a knowledge graph-based data organization and the importance of the concept of a dataset release. We illustrate algorithmic advances in finding suitable parameters for electrical models of neurons or how spatial constraints can be exploited for predicting synaptic connections. Furthermore, we explain how in silico experimentation with such models necessitates specific addressing schemes or requires strategies for an efficient simulation. The entire data-driven approach relies on the systematic validation of the model. We conclude by discussing complementary strategies that not only enable judging the fidelity of the model but also form the basis for its systematic refinements.
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Schürmann, Felix, Jean-Denis Courcol e Srikanth Ramaswamy. "Computational Concepts for Reconstructing and Simulating Brain Tissue". In Advances in Experimental Medicine and Biology, 237–59. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-89439-9_10.
Testo completoAbstract (sommario):
AbstractIt has previously been shown that it is possible to derive a new class of biophysically detailed brain tissue models when one computationally analyzes and exploits the interdependencies or the multi-modal and multi-scale organization of the brain. These reconstructions, sometimes referred to as digital twins, enable a spectrum of scientific investigations. Building such models has become possible because of increase in quantitative data but also advances in computational capabilities, algorithmic and methodological innovations. This chapter presents the computational science concepts that provide the foundation to the data-driven approach to reconstructing and simulating brain tissue as developed by the EPFL Blue Brain Project, which was originally applied to neocortical microcircuitry and extended to other brain regions. Accordingly, the chapter covers aspects such as a knowledge graph-based data organization and the importance of the concept of a dataset release. We illustrate algorithmic advances in finding suitable parameters for electrical models of neurons or how spatial constraints can be exploited for predicting synaptic connections. Furthermore, we explain how in silico experimentation with such models necessitates specific addressing schemes or requires strategies for an efficient simulation. The entire data-driven approach relies on the systematic validation of the model. We conclude by discussing complementary strategies that not only enable judging the fidelity of the model but also form the basis for its systematic refinements.
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Cimini, Amy. "Adjacencies and Its Negations". In Wild Sound, 50–103. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780190060893.003.0002.
Testo completoAbstract (sommario):
“How can worlds of sound be joined?” While Amacher developed this question in realized and unrealized concert music during the mid-1960s, it also conjoined spectral and spatial ways of listening in her inaugural broadcast and environmental projects, City-Links WBFO, Buffalo, and In City, Buffalo 1967 on much different historical and material terrain. A close look at conceptual and notational strategies in Amacher’s electroacoustic percussion work Adjacencies illuminates her musical thought at an early stage and reveals how spectral listening could function as meeting place within which sound and ongoing life exchange intensities elsewhere. Critical comparisons with Karlheinz Stockhausen’s Mikrophonie I (1964) and Anthony Braxton’s Composition No. 9 for Amplified Shoveller Quartet (1969) elaborate how musical forms and experiences amid resonant metals, dramaturgy, and promissory grammar can work in concert or in conflict with historical spaces of biopolitics. Following Adjacencies’ archival traces across the radio broadcast City-Links and festival-like In City moves its connective ways of listening into concrete changes amid so-called redevelopment in urban history and policy debates, entwining social histories and media aesthetics that will inform Amacher’s long-distance projects in the decade to follow.
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"Chapter 9. Ontology-based Structuring of Spectral and Spatial Recording Strategies for Cultural Heritage Assets: Background, State of Affairs, and Future Perspectives". In Digital Techniques for Documenting and Preserving Cultural Heritage, 159–74. ARC, Amsterdam University Press, 2018. http://dx.doi.org/10.1515/9781942401353-013.
Testo completo
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Plaza, Antonio, Javier Plaza, David Valencia e Pablo Martiez. "Parallel Segmentation of Multi-Channel Images Using Multi-Dimentional Mathematical Morphology". In Advances in Image and Video Segmentation, 270–91. IGI Global, 2006. http://dx.doi.org/10.4018/978-1-59140-753-9.ch013.
Testo completoAbstract (sommario):
Multi-channel images are characteristic of certain applications, such as medical imaging or remotely sensed data analysis. Mathematical morphology-based segmentation of multi-channel imagery has not been fully accomplished yet, mainly due to the lack of vector-based strategies to extend classic morphological operations to multidimensional imagery. For instance, the most important morphological approach for image segmentation is the watershed transformation, a hybrid of seeded region growing and edge detection. In this chapter, we describe a vector-preserving framework to extend morphological operations to multi-channel images, and further propose a fully automatic multi-channel watershed segmentation algorithm that naturally combines spatial and spectral/temporal information. Due to the large data volumes often associated with multi-channel imaging, this chapter also develops a parallel implementation strategy to speed up performance. The proposed parallel algorithm is evaluated using magnetic resonance images and remotely sensed hyperspectral scenes collected by the NASA Jet Propulsion Laboratory Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS).
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Hari, Riitta, e Aina Puce. "Analyzing the Data". In MEG - EEG Primer, a cura di Riitta Hari e Aina Puce, 173—C10P325. 2a ed. Oxford University PressNew York, 2023. http://dx.doi.org/10.1093/med/9780197542187.003.0010.
Testo completoAbstract (sommario):
Abstract This chapter discusses the strengths, pitfalls, and practicalities of MEG and EEG data analysis methods and visualization strategies. Data-set segmentation, signal-to-noise considerations, signal levels, and power are examined as these may drive the chosen data analysis strategy. After basic analyses of averaged and unaveraged data, brain microstates, event-related desynchronization/synchronization, temporal spectral evolution, and time-frequency analyses, phase synchronization, and cross-frequency coupling are discussed. Measures of the introduced association and functional/effective connectivity, as studied in the time or frequency domains, include correlation, coherence, phase-locking factor, phase-locking value, phase-lag index and their variants, mutual information, transfer entropy, cross-correlation, Granger causality, dynamic causal modeling, and graph-theoretical analysis. The MEG/EEG source modeling section covers forward and inverse problems, head models, single- and multidipole models, distributed models, and beamformers. After discussion of spatial resolution, source extent, and effects of synchrony complete the topics, the chapter ends with statistical considerations regarding signal detectability in individual and group-level data.
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Rizzo Sierra, José Amílcar, Gastón Sanglier Contreras, Ely Karina Anaya Rivera, César Isaza e Jonny Paul Zavala de Paz. "A Novel Methodology to Study Particulate Material/Aerosol Pollution via Real-Time Hyperspectral Acousto-Optic Intelligent Spectrometry". In Advances in Civil and Industrial Engineering, 32–37. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-7279-5.ch002.
Testo completoAbstract (sommario):
Tactic and strategic management and policing of atmospheric pollution in México, specifically by particulate material (PM) from mobile sources (internal combustion powered vehicles), critically requires state-of-the-science technologies due to the problem's complexity including its public health dimension. The authors consider that proper decision making on the problem would benefit from permanent revision on currently employed PM monitoring and measurement systems and also the effort to improve them. These later currently offer information on O(10^0) ultraviolet-visible-infrared (UV-VIS-IR) spectral bands at O(10^0) spatial resolutions and O(10^1) in [min^-1] temporal resolutions. In contrast, they propose the novel use of acousto-optic tunable filter (AOTF) spectrometry to study PM in atmospheric suspension, capable of offering information on O(10^2) UV, VIS, or IR spectral bands at similar or better spatial and temporal resolutions. The potential of AOTF spectrometry towards PM assessment is clear and the objective is to explore its usefulness.
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Tarraf Ibrahem, Nasser. "A Climate-Crop-Spectral Approach for Wheat Adaptation with Climate Changes in the Arid and Semiarid Regions". In Wheat [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109477.
Testo completoAbstract (sommario):
Wheat is grown under a wide climatic range that extends in subhumid, semiarid and arid environments. The vulnerability of wheat productivity to climate change as a result of drought and heat stress in the arid and semiarid regions is accelerating. Remote sensing data monitors crop growth stages and production simultaneously with climatic elements to extract spatial and temporal causal relationships between yielding factors. Qualitative (stage-stress) and quantitative (production-degree) measurements of wheat productivity give a comprehensive view using spectral sensing techniques in a strategic approach. A TESPAL strategy is built on both TEmporal–SPatial-spectrAL growth profiles and zones of wheat growth stages for engineering the adaptation to climate changes. TESPAL strategy confirms stable wheat productivity based on the following: (1) dealing with the criterion of the thermal-climatic factor through indices of plant breeding science by engineering the adaptation in the agro-climate environments and (2) dealing with the criterion of aqua-climatic factor through indices of agronomic science by engineering the crop production management practices.
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Vlcek, Kamil. "Spatial Navigation Impairment in Healthy Aging and Alzheimer’s Disease". In The Clinical Spectrum of Alzheimer's Disease -The Charge Toward Comprehensive Diagnostic and Therapeutic Strategies. InTech, 2011. http://dx.doi.org/10.5772/20278.
Testo completo
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Gouilleux, B. "Ultrafast 2D NMR". In Fast 2D Solution-state NMR, 186–220. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781839168062-00186.
Testo completoAbstract (sommario):
While most fast 2D NMR strategies rely on short recycling delay or on the sparse sampling of the indirect dimension, ultrafast 2D NMR represents a change of paradigm by carrying out a spatial encoding of the resonance frequencies whereby spins located at different positions undergo distinct evolution periods within the same transient. Once the subsequent encoded signals are read out through gradient-based methods inspired from magnetic resonance imaging techniques, a whole 2D NMR spectrum is obtained in a single scan. This sub-second approach is in principle compatible with any homo- or heteronuclear experiment, making it a versatile tool whose analytical potential has been highlighted in various fields of application. This chapter endeavours to review the main concepts and features of ultrafast 2D NMR. This encompasses spatial encoding methods, detection techniques to read out encoded signals, data processing as well as combined methods. Characteristics and limitations are also discussed along with the improvements that have been developed to push forward the analytical performance of this ultrafast approach.
Atti di convegni sul tema "SPECTRAL - SPATIAL STRATEGIES"
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Yi, Chen, Yong-Qiang Zhao e Jonathan Cheung-Wai Chan. "Spectral Super-Resolution for Multispectral Image Based on Spectral and Spatial Strategies". In IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2019. http://dx.doi.org/10.1109/igarss.2019.8898630.
Testo completo
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Gutman, William M., William A. Peterson e Dennis M. Garvey. "Spatial frequency shifts in Fourier transform spectra". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.ftt2.
Testo completoAbstract (sommario):
High resolution atmospheric transmission spectra collected with a Fourier transform instrument sometimes exhibit small systematic shifts in the apparent positions of spectral features. Although small, these shifts result in line shape distortions such as "S-curving" when, in the data reduction, one spectrum must be divided by another. The origin of the shifting is in small residual angular deviations between the laser reference and measurement beams and the mechanical axis of the spectrometer. Thermal distortion of the instrument resulting from temperature gradients that change from spectrum to spectrum during a data acquisition operation are the source of the angular deviation. The authors typically measure spectra under field conditions by using trailer-mounted instruments. The level of temperature control necessary to eliminate shifting is not possible under these conditions. Strategies must be found to reduce or eliminate the effects during processing. The processing method that is explored here is to measure the relative shift between the individual spectra and then to interpolate one of them to the precise spatial frequency values present in the other prior to point-by-point division. Relatively simple interpolation schemes yield significant reduction of the distortion when applied to simulated data, and smaller but still good reduction when applied to measured spectra.
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Illmann, Raik, Maik Rosenberger e Gunther Notni. "Strategies for Merging Hyperspectral Data of Different Spectral and Spatial Resoultion". In 2018 Digital Image Computing: Techniques and Applications (DICTA). IEEE, 2018. http://dx.doi.org/10.1109/dicta.2018.8615875.
Testo completo
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Zhou, Jun, Jie Liang, Yuntao Qian, Yongsheng Gao e Lei Tong. "On the sampling strategies for evaluation of joint spectral-spatial information based classifiers". In 2015 7th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS). IEEE, 2015. http://dx.doi.org/10.1109/whispers.2015.8075474.
Testo completo
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ADAME SILES, JOSE ANTONIO, DOLORES CATALINA PÉREZ MARÍN, Ana Garrido-Varo, TOM FEARN, FRANCISCO MAROTO MOLINA e JOSÉ EMILIO GUERRERO GINEL. "Evaluation of sampling strategies in grains using spatial distribution surfaces from NIR spectral data". In 17th International Conference on Near Infrared Spectroscopy. Foz do Iguaçu - PR, Brazil: Galoa, 2015. http://dx.doi.org/10.17648/nir-2015-34225.
Testo completo
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Matteoli, Stefania, Francesca Carnesecchi, Marco Diani, Giovanni Corsini e Leandro Chiarantini. "Comparative analysis of hyperspectral anomaly detection strategies on a new high spatial and spectral resolution data set". In Remote Sensing, a cura di Lorenzo Bruzzone. SPIE, 2007. http://dx.doi.org/10.1117/12.738062.
Testo completo
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Ali, Syed A., Gautham Kollu, Sandip Mazumder e P. Sadayappan. "Prediction of Non-Equilibrium Heat Conduction Using Parallel Computation of the Phonon Boltzmann Transport Equation". In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36084.
Testo completoAbstract (sommario):
Non-equilibrium heat conduction, as occurring in modern-day sub-micron semiconductor devices, can be predicted effectively using the Boltzmann Transport Equation (BTE) for phonons. In this article, strategies and algorithms for large-scale parallel computation of the phonon BTE are presented. An unstructured finite volume method for spatial discretization is coupled with the control angle discrete ordinates method for angular discretization. The single-time relaxation approximation is used to treat phonon-phonon scattering. Both dispersion and polarization of the phonons are accounted for. Three different parallelization strategies are explored: (a) band-based, (b) direction-based, and (c) hybrid band/cell-based. Subsequent to validation studies in which silicon thin-film thermal conductivity was successfully predicted, transient simulations of non-equilibrium thermal transport were conducted in a three-dimensional device-like silicon structure, discretized using 604,054 tetrahedral cells. The angular space was discretized using 400 angles, and the spectral space was discretized into 40 spectral intervals (bands). This resulted in ∼9.7×109 unknowns, which are approximately 3 orders of magnitude larger than previously reported computations in this area. Studies showed that direction-based and hybrid band/cell-based parallelization strategies resulted in similar total computational time. However, the parallel efficiency of the hybrid band/cell-based strategy — about 88% — was found to be superior to that of the direction-based strategy, and is recommended as the preferred strategy for even larger scale computations.
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LÓPEZ-GÓMEZ, JULIÁN, e MARCELA MOLINA-MEYER. "COOPERATION AND COMPETITION, STRATEGIC ALLIANCES, AND THE CAMBRIAN EXPLOSION". In Spectral Theory and Nonlinear Analysis with Applications to Spatial Ecology. WORLD SCIENTIFIC, 2005. http://dx.doi.org/10.1142/9789812701589_0006.
Testo completo
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Garai, Anirban, Scott M. Murman e Nateri K. Madavan. "Scale-Resolving Simulations of a Fundamental Trailing-Edge Cooling Slot Using a Discontinuous-Galerkin Spectral-Element Method". In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91146.
Testo completoAbstract (sommario):
Abstract The accurate prediction of turbulent mixing in high-pressure turbines that incorporate various airfoil surface-cooling strategies is becoming increasing critical to the design of modern gas turbine engines where the quest for improved efficiency is driving compressor overall pressure ratios and turbine inlet temperatures to much higher levels than ever before. In the present paper, a recently developed computational capability for accurate and efficient scale–resolving simulations of turbomachinery is extended to study the turbulent mixing mechanism of a simplified abstraction of an airfoil trailing-edge cooling slot — a plane wall jet with finite lip thickness discharging into an ambient flow. The computational capability is based on an entropy–stable, discontinuous–Galerkin approach that extends to arbitrarily high orders of spatial and temporal accuracy. The numerical results show that the present simulations capture the trends observed in the experiments. Discrepancies between the simulations and experiments are believed to be due to differences in the inflow profiles and tunnel side–wall effects. The thick lip configuration leads to a thicker wake and higher unsteadiness in the wall jet compared to the thin lip. A detailed comparison of the turbulent flowfields is presented to highlight differences arising due to lip thickness variations.
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Baz, A. "An Active Acoustic Metamaterial With Tunable Effective Density". In ASME 2009 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2009. http://dx.doi.org/10.1115/smasis2009-1409.
Testo completoAbstract (sommario):
Extensive efforts are being exerted to develop various types of acoustic metamaterials to effectively control the flow of acoustical energy through these materials. However, all these efforts are focused on passive metamaterials with fixed material properties. In this paper, the emphasis is placed on the development of a new class of one-dimensional acoustic metamaterials with tunable effective densities in an attempt to enable the adaptation to varying external environment. More importantly, the active metamaterials can be tailored to have increasing or decreasing variation of the material properties along and across the material volume. With such unique capabilities, physically realizable acoustic cloaks can be achieved and objects treated with these active metamaterials can become acoustically invisible. The theoretical analysis of this class of active acoustic metamaterials is presented and the theoretical predictions are determined for an array of air cavities separated by piezoelectric boundaries. These boundaries control the stiffness of the individual cavity and in turn its dynamical density. Various control strategies are considered to achieve different spectral and spatial control of the density of this class of acoustic metamaterials. A natural extension of this work is to include active control capabilities to tailor the bulk modulus distribution of the metamaterial in order to build practical configurations of acoustic cloaks.