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Multi-dimensional ambiguity function for subarray-based space-time coding radar

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Journal of Systems Engineering and Electronics 2019年第5期30卷 886-896页

作者： LAN Lan LIAO Guisheng XU Jingwei WANG Hanbing National Laboratory of Radar Signal Processing Xidian University

space-time coding radar has been recently proposed and *** is a radar framework which can perform transmit beamforming at the ***,the range resolution decreases when the number of the transmit element increases.A subarray-based space-time coding(sub-STC)radar is explored to alleviate the range resolution *** the proposed radar configuration,an identical waveform is transmitted and it introduces a small time offset in different *** multidimensional ambiguity function of sub-STC radar is defined by considering resolutions in multiple domains including the range,Doppler,angle and probing *** on properties of the multi-dimensional ambiguity function of the sub-STC radar with regard to the spatial coverage,resolution performance and low sidelobes are also *** reveal that the range resolution and low sidelobes performance are improved with the proposed approach.

关键词： space-time coding radar multi-dimensional ambiguity function range resolution wide spatial coverage subarray sidelobe

One Electron Atom in Special Relativity with de Sitter space-time Symmetry(Ⅱ): ——Higher Order Contributions

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Communications in Theoretical Physics 2014年第8期61卷 189-195页

作者：闫沐霖 Interdisciplinary Center for Theoretical Study Department of Modern Physics University of Science and Technology of China

This is a follow of previous work entitled "One Electron Atom in Special Relativity with de Sitter spacetime Symmetry" [Commun. Theor. Phys. 57(2012) 930]. In this paper, we consider the higher order calculations and contributions in the previous framework to solve one electron atoms in de Sitter invariant relativistic quantum mechanics. The next-to-leading-order calculations in 1/R2-expansions show that the fine-structure constant α is variant with cosmologic time going by in the de Sitter invariant special relativistic quantum mechanics with standard FRW cosmologic model.

关键词： hydrogen atom special relativity with de sitter space-time symmetry time variation of physical constants Friedmann–Robertson–Walker(FRW) universe

Theory and practice of runoff space-time distribution

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Science China(Technological Sciences) 2004年第Z1期47卷 90-105页

作者： Thomas M. Over Department of Geology/Geography Eastern Illinois University Charleston IL 61920 USA

Based on the domestic and foreign concerning researches, this paper submits the runoff space-time distribution theory which shows evident scientific significances and powerful practical functions. On the basis of digital basin unit cell deriving from the digital elevation model (DEM) and assumption of linear confluence, this theory has been applied successfully to the runoff correlation researches in humid regions. In order to prove the adaptability of the theory in arid and semi-drought regions, this paper is used to the runoff correlation analysis in Wuding River basin——a tributary of Yellow River Basin, and has gained preliminary effective verification.

关键词： runoff space-time distribution, theory, the Wuding River, correlation coefficient, practice.

A framework of rank-reduced space-time adaptive processing for airborne radar and its applications

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Science China(Technological Sciences) 1997年第5期40卷 505-512页

作者：廖桂生保铮许志勇 Key Laboratory for Radar Signal Processing Xidian University Xi'an 710071 China

A new equivalent formulation of the joint domain space-time optimum processor for airborne phased array radar application is derived. Then a new framework of space-time adaptive processing (STAP) for airborne radar systems which includes most of suboptimum algorithms in the literature is proposed. The performance of two typical rank-reduced time-space joint-domain processors based on Doppler pre-filtering is analyzed in detail based on the proposed framework.

关键词： airborne radar space-time adaptive processing (STAP) adaptive array clutter suppression.

First order QED processes in a spatially flat FLRW space-time with a Milne-type scale factor

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Chinese Physics C 2020年第5期44卷 140-149页

作者： Ion ICotaescu Diana Popescu West University of Timisoara V.Parvan Ave.4RO-300223 TimisoaraRomania

The quantum electrodynamics(QED)in a spatially flat(1+3)-dimensional Friedmann-Lema?tre-Robertson-Walker(FLRW)space-time with a Milne-type scale factor is outlined focusing on the amplitudes of the allowed processes in the first order *** definition of the transition rates is reconsidered such that an appropriate angular behavior of the probability for creation of an electron-positron pair from a photon is obtained,which has a similar rate as the creation of a photon and an electron-positron pair from *** is shown that these processes are allowed only in the first order perturbations,since the photon emission or absorption by an electron or positron are forbidden.

关键词： spatially flat FLRW space-time Milne-type scale factor first order amplitudes transition rates

Data,Disasters,and space-time Entanglements

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International Journal of Disaster Risk Science 2021年第2期12卷 157-168页

作者： Eija Meriläinen Mirka Koro Institute for Risk and Disaster Reduction and Institute for Global Health University College LondonLondonWC1E 6BTUK Department of Management and Organisation Centre for Corporate ResponsibilityHanken School of Economics00101HelsinkiFinland Mary Lou Fulton Teachers College Arizona State UniversityTempeAZ85281USA

Disasters connected to natural hazards can at the same time be unfolding events,as well as structural phenomena with unequal disaster risk constructed over an extended ***,in disaster studies,temporality and spatiality are central,yet often implicit,concepts employed to make sense of the disaster *** this article we explicitly focus on temporality and spatiality within qualitative disaster studies,particularly those containing ethnographic *** use Doreen Massey’s idea of space-time trajectories to analyze and illustrate how in qualitative disaster studies the trajectories of the disaster,research participants,and the researcher entangle in diverse *** focus is on how temporality and spatiality are present in the construction of *** article is mainly conceptual,with illustrations drawn from empirical fieldwork on Valparaíso fire of 2014 in *** interrogate how researchers’sensitivity to temporality and spatiality challenges the conventional notions and practices of“data”in qualitative disaster *** focus in this article is on disaster studies,but it also offers methodological insights to other social sciences that strive to conduct research in the era of“Anthropocene,”with all its shifts and changes,the root causes of which have built over a long time.

关键词： Chile Creata Data Disaster studies Qualitative disaster research space-time

AN INTEGRATION METHOD WITH FITTING CUBIC SPLINE FUNCTIONS TO A NUMERICAL MODEL OF 2ND-ORDER space-time DIFFERENTIAL REMAINDER——FOR AN IDEAL GLOBAL SIMULATION CASE WITH PRIMITIVE ATMOSPHERIC EQUATIONS

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Journal of Tropical Meteorology 2013年第4期19卷 388-396页

作者：辜旭赞张兵王明欢 Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research Institute of Heavy Rain China Meteorological Administration

In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series *** we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline *** the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical *** is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order ***"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original *** addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable ***,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic *** the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,***,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-

关键词： numerical forecast and numerical simulation 2nd-order space-time differential remainder numerical model cubic spline functions Navier-Stokes primitive equations quasi-Lagrangian time-split integration scheme global simulation case

An Iterative Power Allocation Algorithm for Group-wise space-time Block Coding Systems

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Journal of Shanghai Jiaotong university(Science) 2007年第4期12卷 481-485页

作者：张红伟张海滨宋文涛罗汉文刘兴钊 Dept.of Electronic Eng. Shanghai Jiaotong Univ.

An iterative transmit power allocation (PA) algorithm was proposed for group-wise space-time block coding (G-STBC) systems with group-wise successive interference cancellation (GSIC) receivers. Group-wise interference suppression (GIS) filters are employed to separate each group's transmit signals from other interferences and noise. While the total power on all transmit symbols is constrained, all transmit PA coefficients are updated jointly according to the channel information at each iteration. Through PA, each detection symbol has the same post-detection signal to interference-and-noise ratio (SINR). The simulation results verify that the proposed PA algorithm converges at the equilibrium quickly after few iterations, and it achieves much lower bit error rates than the previous single symbol SIC PA and the fixed ratio PA algorithms for G-STBC systems with GSIC receivers .

关键词： power allocation (PA) group-wise space-time block coding (G-STBC) group-wise interference suppression (GIS) group-wise successive interference cancellation (GSIC)

space-time analysis of the changing patterns of population pressure on the ecological environment in China

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Chinese Journal of Population,Resources and Environment 2015年第4期13卷 341-348页

作者： Dongqi Sun Jinliang Jiang Jianbin Xu Liang Zhou Yi Hu Institute of Geographic Sciences and Natural Resources Research CAS School of Geographic and Oceanographic Sciences Nanjing University College of Geography and Planning Ludong University Urban-Rural Planning Administration Center Ministry of Housing and Urban-Rural Development

This paper examines the temporal change and spatial variation of population pressure on the ecological environment in *** have collected sufficient data from the statistical yearbooks of 31 provincial administrative areas in 1990,1995,2000,2005,and *** a geographic information system(GIS) and relevant models,we analyzed the trend of the population pressure on ecological environment and the change of the gravity center of ecological environment *** conclude that:(1) generally,population pressure on the ecological environment in China was becoming higher during1990-2010,especially in some areas where the population and environment were in serious imbalance and the ecological environment experienced severe pollution;(2) during a certain period,population pressure on the ecological environment was becoming lower in some areas,but the ecological environment was getting worse;(3) the areas with super-high population pressure on the ecological environment were Beijing,Tianjin,and Shanghai;(4) the gravity center of population pressure on the ecological environment and the center of ecological environment quality move differently during the study time period,but the general trend was similar- both of them were moving from west to *** on the analysis,this paper also provides some policy suggestions on the control of ecological environment quality.

关键词： Chinese population eco-environment eco-environmental pressure changing trend space-time analysis