Готові списки джерел за темами / Propagation spatial

Добірка наукової літератури з теми "Propagation spatial"

Автор: Grafiati

Опубліковано: 7 липня 2024

Оновлено: 7 липня 2024

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Статті в журналах з теми "Propagation spatial":

Haiyan Chen, Haiyan Chen, Meng Wang Meng Wang, Cong Chen Cong Chen, Lilin Chen Lilin Chen, Qi Li Qi Li, and Kaiqiang Huang Kaiqiang Huang. "Analogy of light propagation in spatial and temporal domains." Chinese Optics Letters 12, s1 (2014): S12601–312602. http://dx.doi.org/10.3788/col201412.s12601.

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Sogo, Takushi, Hiroshi Ishiguro, and Toru Ishida. "Spatial constraint propagation for identifying qualitative spatial structure." Systems and Computers in Japan 31, no. 2 (February 2000): 62–71. http://dx.doi.org/10.1002/(sici)1520-684x(200002)31:2<62::aid-scj7>3.0.co;2-o.

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Maleev, I. D., and G. A. Swartzlander, Jr. "Propagation of spatial correlation vortices." Journal of the Optical Society of America B 25, no. 6 (May 14, 2008): 915. http://dx.doi.org/10.1364/josab.25.000915.

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Chakraborty, Arindam, and Ravi S. Nanjundiah. "Space–Time Scales of Northward Propagation of Convection during Boreal Summer." Monthly Weather Review 140, no. 12 (December 1, 2012): 3857–66. http://dx.doi.org/10.1175/mwr-d-12-00088.1.

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Abstract This study uses precipitation estimates from the Tropical Rainfall Measuring Mission to quantify the spatial and temporal scales of northward propagation of convection over the Indian monsoon region during boreal summer. Propagating modes of convective systems in the intraseasonal time scales such as the Madden–Julian oscillation can interact with the intertropical convergence zone and bring active and break spells of the Indian summer monsoon. Wavelet analysis was used to quantify the spatial extent (scale) and center of these propagating convective bands, as well as the time period associated with different spatial scales. Results presented here suggest that during a good monsoon year the spatial scale of this oscillation is about 30° centered around 10°N. During weak monsoon years, the scale of propagation decreases and the center shifts farther south closer to the equator. A strong linear relationship is obtained between the center/scale of convective wave bands and intensity of monsoon precipitation over Indian land on the interannual time scale. Moreover, the spatial scale and its center during the break monsoon were found to be similar to an overall weak monsoon year. Based on this analysis, a new index is proposed to quantify the spatial scales associated with propagating convective bands. This automated wavelet-based technique developed here can be used to study meridional propagation of convection in a large volume of datasets from observations and model simulations. The information so obtained can be related to the interannual and intraseasonal variation of Indian monsoon precipitation.

Sabín, Carlos. "Light Propagation through Nanophotonics Wormholes." Universe 4, no. 12 (November 29, 2018): 137. http://dx.doi.org/10.3390/universe4120137.

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We consider the propagation of light along a 3D nanophotonic structure with the spatial shape of a spacetime containing a traversable wormhole. We show that waves experience significant changes of phase and group velocities when propagating along this curved space. This experiment can be realized with state-of-the-art nanophotonics technology.

Dzieciuch, Matthew, and T. G. Birdsall. "Spatial matched processing for multipath propagation." Journal of the Acoustical Society of America 82, S1 (November 1987): S73. http://dx.doi.org/10.1121/1.2024961.

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Wang, Kaifa, and Wendi Wang. "Propagation of HBV with spatial dependence." Mathematical Biosciences 210, no. 1 (November 2007): 78–95. http://dx.doi.org/10.1016/j.mbs.2007.05.004.

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Kazemzadeh, Ali, and Ilia Laali Niyat. "Spatial modelling of railway noise propagation." Journal of Geospatial Information Technology 7, no. 1 (May 1, 2019): 145–68. http://dx.doi.org/10.29252/jgit.7.1.145.

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Katragadda, Satya, Jian Chen, and Shaaban Abbady. "Spatial hotspot detection using polygon propagation." International Journal of Digital Earth 12, no. 7 (June 18, 2018): 825–42. http://dx.doi.org/10.1080/17538947.2018.1485754.

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Evers, Frederic M., Willi H. Hager, and Robert M. Boes. "Spatial Impulse Wave Generation and Propagation." Journal of Waterway, Port, Coastal, and Ocean Engineering 145, no. 3 (May 2019): 04019011. http://dx.doi.org/10.1061/(asce)ww.1943-5460.0000514.

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Дисертації з теми "Propagation spatial":

Mahmood, Attiya. "Impact of Antenna Mutual Coupling, Propagation, and Nonreciprocity on Propagation-Based Key Establishment." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6831.

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Propagation-based key establishment is a physical layer method for generating encryption keys based on two radios observing a reciprocal propagation channel. This work explores the impact of mutual coupling when communicating nodes are equipped with multiple antennas, multipath richness in the propagation environment, and practical limitations caused by the nonreciprocal nature of RF circuits on key establishment. First, network theory is used to formulate a model of a realistic communication system which incorporates transmit sources and receive loads, impedance matching networks, low-noise amplifiers (LNAs), mutually coupled antenna arrays, and a passive eavesdropper. Afterwards, a detailed analysis is performed to quantify the impact of coupling, type of impedance matching network, and proximity of a multi-antenna eavesdropper on key rate metrics. Next, the degradation on key establishment caused by the radiocircuitry non-reciprocal contributions to the propagation channel is analyzed. A calibration technique based on total least square algorithm is used to overcome the non-reciprocity. Results demonstrate that the method is highly effective in removing the impact of non-reciprocal circuit contributions over a range of operational parameters. Lastly, for key establishment, the propagation conditions can cause the available key rate to be significantly different from the secure key rate which takes into account the presence of a passive eavesdropper. To study this in detail, a realistic multiple-input multiple-output (MIMO) propagation environment is modeled for two communicating radios and an eavesdropper. Afterwards different propagation conditions are assumed and results demonstrate that secure key rate converges to available key rate when K-factor is small and the eavesdropper is not located very close (< 2.5 wavelength) to one of the nodes.

Dunn, Adam. "A model of wildfire propagation using the interacting spatial automata formalism." University of Western Australia. School of Computer Science and Software Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0071.

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[Truncated abstract] In this thesis, I address the modelling and computer simulation of spatial, eventdriven systems from a computer science perspective. Spatially explicit models of wildland fire (wildfire) behaviour are addressed as the specific application domain. Wildfire behaviour is expressed as a formal model and the associated simulations are compared to existing models and implementations. It is shown that the in- teracting spatial automata formalism provides a general framework for modelling spatial event-driven systems and is appropriate to wildfire systems. The challenge adressed is that of physically realistic modelling of wildfire behaviour in heterogeneous environments . . . Many current models do not incorporate the influence of a neighbourhood (the geometry of the fire front local to an unburnt volume of fuel, for example), but rather determine the propagation of fire using only point information. Whilst neighbourhood-based influence of behaviour is common to cellular automata theory, its use is very rare in existing models of wildfire models. In this thesis, I present the modelling technique and demonstrate its applicability to wildfire systems via a series of simulation experiments, where I reproduce known spatial wildfire dynamics. I conclude that the interacting spatial automata formalism is appropriate as a basis for constructing new computer simulations of wildfire spread behaviour. Simulation results are compared to existing implementations, highlighting the limitations of current models and demonstrating that the new models are capable of greater physical realism.

Hahn, Philip James. "Origination and Propagation of Reaction Diffusion Waves in Three Spatial Dimensions." Cleveland, Ohio : Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1091809306.

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Thesis(Ph.D.)--Case Western Reserve University, 2004
Title from PDF (viewed on 2009-11-23) Department of Mathematics Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center

Hahn, Philip James. "Origination and propagation of reaction diffusion waves in three spatial dimensions." online version, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1091809306.

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Agerskov, Niels. "Adaptable Semi-Automated 3D Segmentation Using Deep Learning with Spatial Slice Propagation." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-241542.

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Even with the recent advances of deep learning pushing the field of medical image analysis further than ever before, progress is still slow due to limited availability of annotated data. There are multiple reasons for this, but perhaps the most prominent one is the amount of time manual annotation of medical images takes. In this project a semi-automated algorithm is proposed, approaching the segmentation problem in a slice by slice manner utilising the prediction of a previous slice as a prior for the next. This both allows the algorithm to segment entirely new cases and gives the user the ability to correct faulty slices, propagating the correction throughout. Results on par with current state of the art is achieved within the domain of the training data. In addition to this, cases outside of the training domain can also be segmented with some accuracy, paving the way for further improvement. The strategy for training the network to utilise auxiliary input lies in the heavy online data augmentation, forcing the network to rely on the provided prior.
Trots att framstegen inom djupinlärning banar vägen för medicinsk bildanalys snabbare än någonsin så finns det ett stort problem, mängden annoterad bilddata. Det har bland annat att göra med att medicinsk bilddata tar väldigt lång tid att annotera manuellt. I detta projektet har en semi-automatisk algoritm utvecklats som tar sig an 3D-segmentering från ett 2D-perspektiv. En bildvolym segmenteras genom att en initialiseringbild annoteras manuellt och används som hjälp för att annotera närliggande bilder i volymen. Detta upprepas sedan för resterande bilder men istället för att manuellt annotera används föregående segmentering av närverket som hjälp. Detta tillåter att algoritmen både kan generalisera till helt nya fall som ej är representerade av träningsdatan, och gör även att felaktigt segmenterade bilder kan korrigeras i efterhand. Korrigeringar kommer då att propageras genom volymen genom att varje segmentering används som hjälp för nästkommande bild. Resultaten är i nivå med motsvarande helautomatiska algoritmer inom träningsdomänen. Den största fördelen gentemot dessa är möjligheten att segmentera helt nya fall. Metoden som används för att träna nätverket att förlita sig på hjälpbilder bygger på kraftig bilddistortion av bilden som ska segmenteras. Detta tvingar nätverket att ta vara på informationen i segmenteringen av föregående bild.

Moustafa, Mahmoud. "Fabrication of Micropatterns for the Spatial Control of Cell Propagation and DIfferentiation." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3555.

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Challenges in the development of successful cell therapies involve engineering and control of cues to regulate the balance between differentiation and self-renewal. However, the complexity of architecture and function make this an intriguing problem in the context of forming functional connections. Here we present the design and fabrication of microstructured scaffolds that present a biomimetic framework along which neural cell lines can organize into oriented constructs. Specifically, we show microfabricated non-linear architectures that promote cellular fate related to propagation of human neuroblastoma cells and directed differentiation towards neurons. By mimicking biological networks that allow for spreading of the cells instead of confining them in a groove or a well, a nonlinear configuration can promote a relaxed, self-supportive cell niche. The tailoring of non-homogeneous adhesion sites via the geometry and the compliance and roughness of the substrate allows a versatile microenvironment that promotes propagation and neuronal differentiation.

De, Rybel Tom. "Temporal-spatial discretization and fractional latency techniques for wave propagation in heterogeneous media." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/20573.

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This thesis presents the development of a novel, transient wave propagation simulator using time-decoupled transmission line models. The models are based on the electro-magnetic transient program (EMTP) power system transient analysis tools, extended to two dimensions. The new tool is targeted at acoustic wave propagation phenomena. The method, called TINA for transient insular nodal analysis, uses temporal interpolation and fractional latency to maintain synchronicity in heterogeneous media. The fractional latency method allows the model cells to operate at a local simulation time step which can be a non-integer ratio of the global simulation time step. This simplifies synchronicity and saves computation time and memory. Thévenin equivalents are used to interface the mesh cells and provide an abstraction of the cell content. Numerically, the method is of the transmission-line matrix (TLM) family. In the thesis, loss-less and distortion-less models are considered. The loss-less transmission line models are studied for their stability and numerical error, for which analytical expressions are derived based on the simulation parameters. A number of new relations were discovered and discussed. The TINA method is evaluated in 2D using acoustic experiments, and also a new method is proposed for obtaining impulse responses in time-domain simulation, based on a periodic, band-limited impulse signals.

DIAS, MAURICIO HENRIQUE COSTA. "ACTUAL MOBILE RADIO PROPAGATION CHANNEL RESPONSES ESTIMATES IN THE SPATIAL AND TEMPORAL DOMAINS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3502@1.

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INSTITUTO MILITAR DE ENGENHARIA
No cenário atual das telecomunicações móveis, os arranjos de antenas voltaram a receber grande atenção dos pesquisadores, especialmente quando esquemas adaptativos de modificação de seus diagramas de radiação são utilizados. Uma das aplicações que exploram o potencial dos arranjos de antenas é o seu uso como forma de aumentar consideravelmente a eficiência espectral dos sistemas móveis atuais e da próxima geração. A outra aplicação em evidência está voltada para sistemas de localização de posição, pois algumas das técnicas conhecidas envolvem a estimação de ângulos-de-chegada usando arranjos de antenas. Diante destas possibilidades, cresce em importância o estudo das variações do canal de propagação rádio móvel no domínio em que o uso dos arranjos de antenas atua: o espacial. O presente trabalho procura contribuir para o contexto em questão, com uma investigação experimental do canal real rádio-móvel nos domínios temporal (retardos) e espacial (ângulos-de-chegada). No que se refere ao contexto nacional, contribuições similares baseadas em simulações já são encontradas; baseadas em medidas não. Em particular, sondagens na faixa de 1,8 GHz em ambientes internos típicos foram realizadas. Duas técnicas distintas de sondagem temporalespacial foram implementadas, tomando por base uma sonda de canal faixa-larga montada e testada com sucesso, como contribuição principal de uma dissertação de mestrado recentemente apresentada por um integrante do mesmo grupo de pesquisa ao qual esta tese está vinculada. Uma das técnicas sintetiza o arranjo realizando as sondagens com uma única antena que é sucessivamente deslocada para ocupar as posições correspondentes às dos elementos do arranjo. A outra técnica emprega um arranjo real. Em ambas, a configuração mais simples para um arranjo foi utilizada: a linear uniforme. As sondagens não forneciam diretamente os espectros espaciais-temporais. As estimativas dos espectros foram processadas posteriormente, aplicando técnicas como o correlograma para o domínio do retardo, e quatro técnicas distintas para o domínio espacial, que foi o foco principal deste trabalho: duas convencionais; e duas paramétricas, com potencial de aumentar a resolução das estimativas, assumindo hipóteses razoáveis sobre as respostas esperadas. De posse das respostas espectrais estimadas, comparações com estimativas teóricas permitiram uma análise de desempenho das técnicas utilizadas. Adicionalmente à investigação experimental do canal espacial, procurou-se verificar o potencial da aplicação da teoria de wavelets ao estudo do canal rádiomóvel. Em especial, uma das principais aplicações daquela teoria foi testada como técnica de pós-processamento das respostas espectrais no domínio do retardo. A supressão de ruído por decomposição wavelet foi aplicada a um vasto conjunto de medidas de canal disponíveis, fruto de trabalhos anteriores do grupo de pesquisa ao qual esta tese está vinculada, com resultados expressivos.
In the present mobile communications scenario, researchers have turned once again special attention to antennae arrays, particularly when adaptive schemes are employed to modify its radiation patterns. One of its main applications results in considerable increases to the spectral efficiency of present and next generation mobile systems. The other major application is headed towards position location systems, since some of the known techniques comprise angle-of-arrival estimation using antennae arrays. Under such possibilities, mobile radio propagation channel variations studies grow in relevance, specially regarding the antennae arrays main domain of action: the spatial domain. The present work tries to contribute to the overstated context, experimentally investigating the actual mobile radio channel over the temporal (delays) and spatial (angles of arrival) domains. Regionally speaking, similar contributions based on simulations are already found, but none based on measurements. In special, 1.8 GHz indoor soundings have been carried out. Two different temporal spatial sounding techniques have been deployed, based on na available wideband channel sounder successfully assembled and tested as the major contribution of a MSc. dissertation recently presented by a member of the same research team to which this thesis belongs. One of such techniques sinthesyzes the array carrying the sounding out with a single antenna, which is successively moved to occupy the spots corresponding to the array elements. The other method employs an actual array. For both cases, the simplest array configuration has been used: the uniform linear one. Space-time spectra were not directly available in real time during the soundings. Its estimates have been processed later, applying techniques such as the correlogram over the delay domain, and four distinct methods over the spatial domain, the main focus of the present work. Two conventional methods have been used, as well as two parametric ones, potentially capable to increase the estimates resolution, assuming reasonable hypotheses regarding the expected responses. With the estimated spectral responses in hands, comparisons with theoretical estimates allowed a performance assessment of the employed methods. In addition to the spatial channel experimental investigation, the wavelets theory potential of application to the mobile-radio channel study has been checked out. Notably, one of the wavelets theory major applications has been tested as a post-processing technique to improve delay-domain spectral responses. Wavelet decomposition based de-noising has been applied to a huge measurements ensemble, available as the product of previous works of the research group to which this thesis is attached, leading to remarkable results.

Kim, Hyunki. "Spatial variability in soils stiffness and strength /." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07132005-194445/.

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Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006.
Mayne, Paul, Committee Member ; Frost, David, Committee Member ; Santamarina, Carlos, Committee Chair ; Rix, Glenn, Committee Member ; Ruppel, Carolyn, Committee Member.

Wiles, Andrew Donald. "Modelling Framework for Radio Frequency Spatial Measurement." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/771.

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The main crux of this thesis was to produce a model that was capable of simulating the theoretical performance of different configurations for a spatial measurement system using radio frequency technology. It has been important to study new modalities of spatial measurement since spatial measurement systems are an enabling technology that have allowed for the creation of better medical procedures and techniques, provided valuable data for motion capture in animation and biomechanics, and have improved the quality of manufacturing processes in many industries. However, there has been room for improvement in the functional design and accuracy of spatial measurement systems that will enhance current applications and further develop new applications in medicine, research and industry.

In this thesis, a modelling framework for the investigation of spatial measurement based on radio frequency signals was developed. The simulation framework was designed for the purpose of investigating different position determination algorithms and sensor geomatries. A finite element model using the FEMLAB partial differential equation modelling tool was created for a time-domain model of electromagnetic wave propagation in order to simulate the radio frequency signals travelling from a transmitting source antenna to a set of receiving antenna sensors. Electronic line signals were obtained using a simple receiving infinitesimal dipole model and input into a time difference of arrival localization algorithm. The finite element model results were validated against a set of analytical solutions for the free space case. The accuracy of the localization algorithm was measured against a set of possible applications for a potential radio frequency spatial measurement system design.

It was concluded that the simulation framework was successful should one significant deficiency be corrected in future research endeavours. A phase error was observed in the signals extracted at the receiving antenna locations. This phase error, which can be up to 40°, was attributed to the zeroth order finite elements implemented in the finite element model. This phase error can be corrected in the future if higher order vector elements are introduced into future versions of FEMLAB or via the development of custom finite element analysis software but were not implemented in this thesis due to time constraints. Other improvements were also suggested for future work.

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Книги з теми "Propagation spatial":

Heuvelink, Gerard B. M. Error propagation in quantitative spatial modelling: Applications in geographical information systems. [Amsterdam]: Koninklijk Nederlands Aardrijkskundig Genootschap, 1993.

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Groters, Douglas J. The temporal and spatial variability of the marine atmospheric boundary layer and its effect on electromagnetic propagation in and around the Greenland Sea marginal ice zone. Monterey, California: Naval Postgraduate School, 1988.

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Barué, Gérard. Télécommunications et infrastructure: Liaisons hertziennes, spatiales, optiques. Paris: Ellipses, 2003.

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Laboratory, Wave Propagation, ed. The longitudinal-transverse spatial coherence function for a spherical wave propagating through homogeneous atmospheric turbulence: Implications for RASS. Boulder, Colo: Wave Propagation Laboratory : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, 1991.

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Lataitis, R. J. The longitudinal-transverse spatial coherence function for a spherical wave propagating through homogeneous atmospheric turbulence: Implications for RASS. Boulder, Colo: Wave Propagation Laboratory : U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, 1991.

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Willis, Zdenka S. The spatial and temporal variability of the Arctic atmospheric boundary layer and its effect on electromagnetic (EM) propagation. 1987.

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Wang, Bin. Intraseasonal Modulation of the Indian Summer Monsoon. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.616.

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The strongest Indian summer monsoon (ISM) on the planet features prolonged clustered spells of wet and dry conditions often lasting for two to three weeks, known as active and break monsoons. The active and break monsoons are attributed to a quasi-periodic intraseasonal oscillation (ISO), which is an extremely important form of the ISM variability bridging weather and climate variation. The ISO over India is part of the ISO in global tropics. The latter is one of the most important meteorological phenomena discovered during the 20th century (Madden & Julian, 1971, 1972). The extreme dry and wet events are regulated by the boreal summer ISO (BSISO). The BSISO over Indian monsoon region consists of northward propagating 30–60 day and westward propagating 10–20 day modes. The “clustering” of synoptic activity was separately modulated by both the 30–60 day and 10–20 day BSISO modes in approximately equal amounts. The clustering is particularly strong when the enhancement effect from both modes acts in concert. The northward propagation of BSISO is primarily originated from the easterly vertical shear (increasing easterly winds with height) of the monsoon flows, which by interacting with the BSISO convective system can generate boundary layer convergence to the north of the convective system that promotes its northward movement. The BSISO-ocean interaction through wind-evaporation feedback and cloud-radiation feedback can also contribute to the northward propagation of BSISO from the equator. The 10–20 day oscillation is primarily produced by convectively coupled Rossby waves modified by the monsoon mean flows. Using coupled general circulation models (GCMs) for ISO prediction is an important advance in subseasonal forecasts. The major modes of ISO over Indian monsoon region are potentially predictable up to 40–45 days as estimated by multiple GCM ensemble hindcast experiments. The current dynamical models’ prediction skills for the large initial amplitude cases are approximately 20–25 days, but the prediction of developing BSISO disturbance is much more difficult than the prediction of the mature BSISO disturbances. This article provides a synthesis of our current knowledge on the observed spatial and temporal structure of the ISO over India and the important physical processes through which the BSISO regulates the ISM active-break cycles and severe weather events. Our present capability and shortcomings in simulating and predicting the monsoon ISO and outstanding issues are also discussed.

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Частини книг з теми "Propagation spatial":

Bivand, Roger. "Error Propagation in Spatial Prediction." In Encyclopedia of GIS, 1–5. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-23519-6_367-2.

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Bivand, Roger. "Error Propagation in Spatial Prediction." In Encyclopedia of GIS, 552–56. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-17885-1_367.

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Bivand, Roger. "Error Propagation in Spatial Prediction." In Encyclopedia of GIS, 287–90. Boston, MA: Springer US, 2008. http://dx.doi.org/10.1007/978-0-387-35973-1_367.

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Faragó, István, and Róbert Horváth. "On a Spatial Epidemic Propagation Model." In Mathematics in Industry, 517–25. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-23413-7_72.

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Petruskevicius, R. "Nonparaxial Propagation of Parametric Spatial Solitons." In Soliton-driven Photonics, 91–94. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0682-8_10.

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Altman, C., and K. Suchy. "Wave propagation in a cold magnetoplasma." In Reciprocity, Spatial Mapping and Time Reversal in Electromagnetics, 1–45. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1530-1_1.

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Altman, C., and K. Suchy. "Wave propagation in a cold magnetoplasma." In Reciprocity, Spatial Mapping and Time Reversal in Electromagnetics, 6–52. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-015-7915-5_2.

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Cencini, Massimo, Cristobal Lopez, and Davide Vergni. "Reaction-Diffusion Systems: Front Propagation and Spatial Structures." In Lecture Notes in Physics, 187–210. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-39668-0_9.

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Park, Jinsun, Kyungdon Joo, Zhe Hu, Chi-Kuei Liu, and In So Kweon. "Non-local Spatial Propagation Network for Depth Completion." In Computer Vision – ECCV 2020, 120–36. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58601-0_8.

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Rituerto, Alejandro, Roberto Manduchi, Ana C. Murillo, and J. J. Guerrero. "3D Spatial Layout Propagation in a Video Sequence." In Lecture Notes in Computer Science, 374–82. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11755-3_42.

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Тези доповідей конференцій з теми "Propagation spatial":

Rowden, Alexander, Süleyman Aslan, Eric Krokos, Kirsten Whitley, and Amitabh Varshney. "WaveRider: Immersive Visualization of Indoor Signal Propagation." In SUI '22: Symposium on Spatial User Interaction. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3565970.3567689.

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Maleev, Ivan D., and Grover A. Swartzlander. "Propagation of Spatial Correlation Vortices." In Frontiers in Optics. Washington, D.C.: OSA, 2005. http://dx.doi.org/10.1364/fio.2005.fthw5.

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Bhattacharjee, Abhinandan, Mritunjay K. Joshi, Suman Karan, Jonathan Leach, and Anand K. Jha. "Propagation-induced spatial entanglement revival." In Quantum Information and Measurement. Washington, D.C.: OSA, 2021. http://dx.doi.org/10.1364/qim.2021.m2a.6.

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Oliver, Dev, Petko Bakalov, Sangho Kim, and Erik Hoel. "Attribute Propagation for Utilities." In SSTD '21: 17th International Symposium on Spatial and Temporal Databases. New York, NY, USA: ACM, 2021. http://dx.doi.org/10.1145/3469830.3470907.

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Agarwal, G. S. "Generation and Propagation of Spatial Coherence." In Frontiers in Optics. Washington, D.C.: OSA, 2004. http://dx.doi.org/10.1364/fio.2004.jma2.

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Prahl, Scott A., Donald D. Duncan, and David G. Fischer. "Monte Carlo propagation of spatial coherence." In SPIE BiOS: Biomedical Optics, edited by Adam Wax and Vadim Backman. SPIE, 2009. http://dx.doi.org/10.1117/12.809603.

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Ho, Seng-Tiong. "Treatment of spatial propagation and localized states in quantum optics." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/oam.1993.thl.7.

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In this paper, we show that a localized photon annihilation operators b ^ can be constructed to treat spatial propagation and atom-field interaction problem in quantum optics, where b ^ can be expressed as an integral over the +z or −z propagating part of the vector potential operator.

Dugan, Jordan, Tom J. Smy, and Shulabh Gupta. "Emulating Spatial Dispersion Using Non-Spatially Dispersive Periodic Metasurfaces." In 2024 18th European Conference on Antennas and Propagation (EuCAP). IEEE, 2024. http://dx.doi.org/10.23919/eucap60739.2024.10501243.

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Porrat, Dana, Eli Kaminsky, and Moshe Uziel. "Spatial stability in indoor radio propagation channels." In 2008 IEEE 25th Convention of Electrical and Electronics Engineers in Israel (IEEEI). IEEE, 2008. http://dx.doi.org/10.1109/eeei.2008.4736715.

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Harris, Jeremie, Frederic Bouchard, Harjaspreet Mand, Nicolas Bent, Enrico Santamato, Robert Boyd, and Ebrahim Karimi. "Recovery of quantum coherence by spatial propagation." In 2015 Photonics North. IEEE, 2015. http://dx.doi.org/10.1109/pn.2015.7292492.

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Звіти організацій з теми "Propagation spatial":

Heaney, Kevin. Spatial Structure of Deep Water Acoustic Propagation. Fort Belvoir, VA: Defense Technical Information Center, September 2008. http://dx.doi.org/10.21236/ada533364.

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Hart, Carl R., and Gregory W. Lyons. A Measurement System for the Study of Nonlinear Propagation Through Arrays of Scatterers. Engineer Research and Development Center (U.S.), November 2020. http://dx.doi.org/10.21079/11681/38621.

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Various experimental challenges exist in measuring the spatial and temporal field of a nonlinear acoustic pulse propagating through an array of scatterers. Probe interference and undesirable high-frequency response plague typical approaches with acoustic microphones, which are also limited to resolving the pressure field at a single position. Measurements made with optical methods do not have such drawbacks, and schlieren measurements are particularly well suited to measuring both the spatial and temporal evolution of nonlinear pulse propagation in an array of scatterers. Herein, a measurement system is described based on a z-type schlieren setup, which is suitable for measuring axisymmetric phenomena and visualizing weak shock propagation. In order to reduce directivity and initiate nearly spherically-symmetric propagation, laser induced breakdown serves as the source for the nonlinear pulse. A key component of the schlieren system is a standard schliere, which allows quantitative schlieren measurements to be performed. Sizing of the standard schliere is aided by generating estimates of the expected light refraction from the nonlinear pulse, by way of the forward Abel transform. Finally, considerations for experimental sequencing, image capture, and a reconfigurable rod array designed to minimize spurious wave interactions are specified. 15.

Gertner, George. Uncertainty Propagation and Partitioning in Spatial Prediction of Topographical Factor for RUSLE. Fort Belvoir, VA: Defense Technical Information Center, July 2000. http://dx.doi.org/10.21236/ada379657.

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Minkoff, S. E. Spatial parallelism of a 3D finite difference, velocity-stress elastic wave propagation code. Office of Scientific and Technical Information (OSTI), December 1999. http://dx.doi.org/10.2172/750170.

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Ferguson, J. A., and C. H. Shellman. Spatial Smoothing of Ionospheric Parameters for Use in the High-Frequency Benchmark Propagation Analysis Program. Fort Belvoir, VA: Defense Technical Information Center, November 1991. http://dx.doi.org/10.21236/ada244532.

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Alter, Ross, Michelle Swearingen, and Mihan McKenna. The influence of mesoscale atmospheric convection on local infrasound propagation. Engineer Research and Development Center (U.S.), February 2024. http://dx.doi.org/10.21079/11681/48157.

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Infrasound—that is, acoustic waves with frequencies below the threshold of human hearing—has historically been used to detect and locate distant explosive events over global ranges (≥1,000 km). Simulations over these ranges have traditionally relied on large-scale, synoptic meteorological information. However, infrasound propagation over shorter, local ranges (0–100 km) may be affected by smaller, mesoscale meteorological features. To identify the effects of these mesoscale meteorological features on local infrasound propagation, simulations were conducted using the Weather Research and Forecasting (WRF) meteorological model to approximate the meteorological conditions associated with a series of historical, small-scale explosive test events that occurred at the Big Black Test Site in Bovina, Mississippi. These meteorological conditions were then incorporated into a full-wave acoustic model to generate meteorology-informed predictions of infrasound propagation. A series of WRF simulations was conducted with varying degrees of horizontal resolution—1, 3, and 15 km—to investigate the spatial sensitivity of these infrasound predictions. The results illustrate that convective precipitation events demonstrate potentially observable effects on local infrasound propagation due to strong, heterogeneous gradients in temperature and wind associated with the convective events themselves. Therefore, to accurately predict infrasound propagation on local scales, it may be necessary to use convection-permitting meteorological models with a horizontal resolution ≤4 km at locations and times that support mesoscale convective activity.

Tovar, Anthony. Off-axis multimode light beam propagation in tapered lenslike media including those with spatial gain or loss variation. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.5711.

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Pettit, Chris, and D. Wilson. A physics-informed neural network for sound propagation in the atmospheric boundary layer. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/41034.

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We describe what we believe is the first effort to develop a physics-informed neural network (PINN) to predict sound propagation through the atmospheric boundary layer. PINN is a recent innovation in the application of deep learning to simulate physics. The motivation is to combine the strengths of data-driven models and physics models, thereby producing a regularized surrogate model using less data than a purely data-driven model. In a PINN, the data-driven loss function is augmented with penalty terms for deviations from the underlying physics, e.g., a governing equation or a boundary condition. Training data are obtained from Crank-Nicholson solutions of the parabolic equation with homogeneous ground impedance and Monin-Obukhov similarity theory for the effective sound speed in the moving atmosphere. Training data are random samples from an ensemble of solutions for combinations of parameters governing the impedance and the effective sound speed. PINN output is processed to produce realizations of transmission loss that look much like the Crank-Nicholson solutions. We describe the framework for implementing PINN for outdoor sound, and we outline practical matters related to network architecture, the size of the training set, the physics-informed loss function, and challenge of managing the spatial complexity of the complex pressure.

Wilson, D., Vladimir Ostashev, and Max Krackow. Phase-modulated Rice model for statistical distributions of complex signals. Engineer Research and Development Center (U.S.), August 2023. http://dx.doi.org/10.21079/11681/47379.

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The basic Rice model is commonly used to describe complex signal statistics from randomly scattered waves. It correctly describes weak (Born) scattering, as well as fully saturated scattering, and smoothly interpolates between these extremes. However, the basic Rice model is unsuitable for situations involving scattering by random inhomogeneities spanning a broad range of spatial scales, as commonly occurs for sound scattering by turbulence in the atmospheric boundary layer and other scenarios. In such scenarios, the phase variations are often considerably stronger than those predicted by the basic Rice model. Therefore, the basic Rice model is extended to include a random modulation in the signal phase, which is attributable to the influence of the largest, most energetic inhomogeneities in the propagation medium. Various joint and marginal distributions for the complex signal statistics are derived to incorporate the phase-modulation effect. Approximations of the phase-modulated Rice model involving the Nakagami distribution for amplitude, and the wrapped normal and von Mises distributions for phase, are also developed and analyzed. The phase-modulated Rice model and various approximations are shown to greatly improve agreement with simulated data for sound propagation in the near-ground atmosphere.

Wilson, D., Matthew Kamrath, Caitlin Haedrich, Daniel Breton, and Carl Hart. Urban noise distributions and the influence of geometric spreading on skewness. Engineer Research and Development Center (U.S.), November 2021. http://dx.doi.org/10.21079/11681/42483.

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Statistical distributions of urban noise levels are influenced by many complex phenomena, including spatial and temporal variations in the source level, multisource mixtures, propagation losses, and random fading from multipath reflections. This article provides a broad perspective on the varying impacts of these phenomena. Distributions incorporating random fading and averaging (e.g., gamma and noncentral Erlang) tend to be negatively skewed on logarithmic (decibel) axes but can be positively skewed if the fading process is strongly modulated by source power variations (e.g., compound gamma). In contrast, distributions incorporating randomly positioned sources and explicit geometric spreading [e.g., exponentially modified Gaussian (EMG)] tend to be positively skewed with exponential tails on logarithmic axes. To evaluate the suitability of the various distributions, one-third octave band sound-level data were measured at 37 locations in the North End of Boston, MA. Based on the Kullback-Leibler divergence as calculated across all of the locations and frequencies, the EMG provides the most consistently good agreement with the data, which were generally positively skewed. The compound gamma also fits the data well and even outperforms the EMG for the small minority of cases exhibiting negative skew. The lognormal provides a suitable fit in cases in which particular non-traffic noise sources dominate.