Polarimetric super-resolution algorithm for radar range imaging via spatial smoothing processing

A full-polarimetric super-resolution algorithm with spatial smoothing processing is presented for one-dimensional（1-D）radar imaging.The coherence between scattering centers is minimized by using spatial smoothing processing（SSP）.Then the range and polarimetric scattering matrix of the scattering centers are estimated.The impact of different lengths of the smoothing window on the imaging quality is mainly analyzed with different signal-to-noise ratios（SNR）.Simulation and experimental results show that an improved radar super-resolution range profile and more precise estimation can be obtained by adjusting the length of the smoothing window under different SNR conditions.

Research on temporal and spatial distribution,evolutionary character and mechanism of crustal deformation field before and after the Tangshan earthquake

According to the data of precise relevelling and deformation measurement across faults, the temporal and spatial evolution process of crustal deformation field in the source and peripheral regions of the Tangshan earthquake (1976, M S=7.8), from 22 years before the earthquake to 9 years after, is described with the method of crustal deforma tion pattern dynamics. The crustal unstable zones first occur in the exterior, and then surround the focal region by contracting from the exterior to the interior, when the focal region appears to be unstable but does not lose stability. After the transient stable state, the second unstable process from the exterior to interior appears, which results in the instability of focal region. 'Deformation gap', 'earthquake gap' and 'locked fault zone' occur before instability, and their spatial distributions overlap, but their occurrence times have little differences. The earthquake occurs after the impending pre slide of the faults in the focal region. The studied results of the evolution process of crustal deformation field are identical with each other and with that of numeric simulation of crustal stress field, which supports the evolution model of seismogenic system with a strong body as its core.

Feasibility of a novel beamforming algorithm via retrieving spatial harmonics

This paper introduces an algorithm for beamforming systems by the aid of multidimensional harmonic retrieval(MHR).This algorithm resolves problems,removes limitations of sampling and provides a more robust beamformer.A new sample space is created that can be used for estimating weights of a new beamforming called spatial-harmonics retrieval beamformer(SHRB).Simulation results show that SHRB has a better performance,accuracy,and applicability and more powerful eigenvalues than conventional beamformers.A simple mathematical proof is provided.By changing the number of harmonics,as a degree of freedom that is missing in conventional beamformers,SHRB can achieve more optimal outputs without increasing the number of spatial or temporal samples.We will demonstrate that SHRB offers an improvement of 4 dB in signal to noise ratio(SNR) in bit error rate(BER) of 10~(-4) over conventional beamformers.In the case of direction of arrival(DOA) estimation,SHRB can estimate the DOA of the desired signal with an SNR of-25 dB,when conventional methods cannot have acceptable response.

Estimation of spatially distributed processes using mobile sensor networks with missing measurements

This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to better reflect the reality in the sensor network.To improve the estimation performance for the spatially distributed process,a network of sensors which are allowed to move within the spatial domain is used.We aim to design an estimator which is used to approximate the distributed process and the mobile trajectories for sensors such that,for all possible missing measurements,the estimation error system is globally asymptotically stable in the mean square sense.By constructing Lyapunov functionals and using inequality analysis,the guidance scheme of every sensor and the convergence of the estimation error system are obtained.Finally,a numerical example is given to verify the effectiveness of the proposed estimator utilizing the proposed guidance scheme for sensors.

LATE MESOZOIC SUBDUCTION PROCESS BENEATH SOUTHEASTERN CHINA AS REVEALEDBY THE SPATIAL- TEMPORAL PATTERN OFMAGMATISM

Southeastern China covers an extensive area from the lowerreaches of the Yangtze Riverto the southeast coastof China mainland.One of its main geological features isthe extensiveJura- Cretaceous (Yanshanian) magmatism and related metallogenesis. Recently,some re-searchers advocate the mantle plume model as an explanation,but all of their evidences artoo ambiguous.Meanwhile,the seaward convex shape of the SE China coastline,which isdominantly composed of Jura- Cretaceous batholiths and volcanic strata,implies thatit was aconvergent margin between SE China continent and the palaeo- Pacific plate during the lateMesozoic era.Fora betterunderstanding on the relation among magmatism,tectonic regimeand dynamics,the spatial- temporal pattern of late Mesozoic (180 - 90 Ma) igneous rocks isconstructed by nearly2 0 0 isotope age valuesfrom literatures.Among these age values,mostwere obtained by Rb- Sr isochron method,and others from zircon U- Pb or40 Ar- 3

Causal Circular Narrative and Time-Space Construction of the Movie Little Big Woman

Chinese film Little Big Woman takes the father’s funeral as the main line to tell the story of family affection and real-life emotional entanglements.In the narrative with multiple clues,we go back to find the hidden reasons,and the gradually clear reflection of the past is related to the real situation of the characters.Causal cycle narrative is not only a narrative strategy,but also a narrative logic with deep Chinese traditional cultural and philosophical connotations.

Understanding cultivated land dynamics and its driving forces in northern China during 1983-2001

Based on the long-term serial NOAA/NDVI dataset during 1983-1999 and SPOT/VGT dataset in 2001, the land use/cover change information in the 13 provinces of northern China was extracted based on the analysis of the cultivated landscape characteristics at first, then the effects of human activities on cultivated land process were explored by GIS and the driving forces of cultivated land change were investigated. The conclusions can be drawn as follows： （1） The constant increase of weak ecological function land as desert and cultivated land and the decrease of the ecological function land of forest and shrub were the main characteristics of the land use/cover change in the 13 provinces from 1983 to 1999, which showed the effects on the ecological adjustment fimction. However, such situations were changed to some extent in the 2000s because of the eco-construction policy of the government. （2） From 1983 to 2001, the Barycenter of cultivated land tended to move from northeast to southwest with the topography and transportation situations being the main influences on the cultivated land distribution. It is found that the cultivated land use intensity decreased noticably with the increase of distance from the main communication arteries. （3） The improvement of the people＇s living standard is closely related with the cultivated land change. The structural adjustment in the agricultural land caused by economic development and the improvement of the people＇s living standard ig an important factor affecting the cultivated land change in northern China from 1983 to 2001

Modeling forest fires in Mazandaran Province, Iran

We used a spafio-temporal shot-noise Cox process to study the distribution of forest fires reported between 2006 and 2010 in the Mazandaran Province＇s forests. The fitted model shows that daily temperature, altitude, and slope-exposure impacted fire occurrence. Forest fire occurred in the region had an aggregated behavior, which increased in radius below 1-km away from fired areas; a periodic pattern of fire occurrence in the region was verified. The risk of forest fire is significantly higher for areas with southern exposure and slope between 30° and 50°, northern exposure and slope between 0° and 50°, and eastern exposure and slope between 0° and 30°. The risk of fire was also significantly higher at altitudes between 1350 and 3000 m asl. Human causes were the main ignition source for forest fires in the region. The fire occurrence rate stayed above average during the drought period from September 2008 to September 2009. Our findings could lead to the development of fire-response and fire-suppression strategies appropriate to specific regions.

Fast Web - Based Data Transmission

Since web based GIS processes large size spatial geographic information on internet, we should try to improve the efficiency of spatial data query processing and transmission. This paper presents two efficient methods for this purpose: division transmission and progressive transmission methods. In division transmission method, a map can be divided into several parts, called “tiles”, and only tiles can be transmitted at the request of a client. In progressive transmission method, a map can be split into several phase views based on the significance of vertices, and a server produces a target object and then transmits it progressively when this spatial object is requested from a client. In order to achieve these methods, the algorithms, “tile division”, “priority order estimation” and the strategies for data transmission are proposed in this paper, respectively. Compared with such traditional methods as “map total transmission” and “layer transmission”, the web based GIS data transmission, proposed in this paper, is advantageous in the increase of the data transmission efficiency by a great margin.

Characterizing changes in land cover and forest fragmentation from multitemporal Landsat observations(1993-2018)in the Dhorpatan Hunting Reserve,Nepal

Natural forces and anthropogenic activities greatly alter land cover,deteriorate or alleviate forest fragmentation and affect biodiversity.Thus land cover and forest fragmentation dynamics have become a focus of concern for natural resource management agencies and biodiversity conservation communities.However,there are few land cover datasets and forest fragmentation information available for the Dhorpatan Hunting Reserve(DHR)of Nepal to develop targeted biodiversity conservation plans.In this study,these gaps were filled by characterizing land cover and forest fragmentation trends in the DHR.Using five Landsat images between 1993 and 2018,a support vector machine algorithm was applied to classify six land cover classes:forest,grasslands,barren lands,agricultural and built-up areas,water bodies,and snow and glaciers.Subsequently,two landscape process models and four landscape metrics were used to depict the forest fragmentation situations.Results showed that forest cover increased from 39.4%in 1993 to 39.8%in 2018.Conversely,grasslands decreased from 38.2%in 1993 to 36.9%in 2018.The forest shrinkage was responsible for forest loss during the period,suggesting that the loss of forest cover reduced the connectivity between forest and nonforested areas.Expansion was the dominant component of the forest restoration process,implying that it avoided the occurrence of isolated forests.The maximum value of edge density and perimeter area fractal dimension metrics and the minimum value of aggregation index were observed in 2011,revealing that forests in this year were most fragmented.These specific observations from the current analysis can help local authorities and local communities,who are highly dependent on forest resources,to better develop local forest management and biodiversity conservation plans.

Fast time-division color electroholography using a multiple-graphics processing unit cluster system with a single spatial light modulator

We demonstrate fast time-division color etectroholography using a multiple-graphics-processing-unit （GPU） cluster system with a spatial light modulator and a controller to switch the color of the reconstructing light. The controller comprises a universal serial bus module to drive the liquid crystal optical shutters. By using the controller, the computer-generated hologram （CGH） display node of the multiple-GPU cluster system synchronizes the display of the CGH with the color switching of the reconstructing light. Fast time-division color electroholography at 20 fps is realized for a three-dimensional object comprising 21,000 points per color when 13 GPUs are used in a multiple-GPU cluster system.

Motor Imagery EEG Fuzzy Fusion of Multiple Classification

Due to the volume conduction,electroencephalogram（EEG） gives a rather blurred image of brain activities. It is a challenge for generating satisfactory performance with EEG. This paper studies the multiple areas fusion of EEG classifiers to improve the motor imagery EEG classification performance. Two feature extraction methods are employed to extract the feature from three different areas of EEG. One is power spectral density（PSD）, and the other is common spatial patterns（CSP）. Classifiers are designed based on the well-known linear discrimination analysis（LDA）. The fusion of the individual classifiers is realized by means of the Choquet fuzzy integral. It is demonstrated that the proposed method comes with better performance compared with the individual classifier.

Relative importance of spatial processes and environmental factors in shaping alpine meadow communities

Spatial processes and environmental control are the two distinct,yet not mutually exclusive forces of community structuring,but the relative importance of these factors is controversial due to the speciesspecific dispersal ability,sensitivity towards environmental variables,organism’s abundance and the effect of spatial scale.In the present paper,we explored spatial versus environmental control in shaping community composition(i.e.b-diversity)and species turnover(i.e.change of b-diversity)at an alpine meadow along a slope aspect gradient on the Qinghai–Tibetan Plateau at different spatial scales of sampling(quadrats and plots),by taking account of seed dispersal mode and abundance.Methods We examined the relative importance of spatial processes and environmental factors using all species and four additional subsets of selected species.Moreover,we attempted to explore the effect of scale(quadrat refers to scale of;0.3 m and plot of;8 m)on their counter balance.The data were analyzed both by variation partitioning and multiple regressions on distance matrices.The spatial structure was modelled using Moran’s eigenvector maps(MEM).Important Findings Both spatial processes and environmental factors were important determinants of the community composition and species turnover.The community composition in the alpine meadow was controlled by spatially structured environment(17.6%),space independent of environment(18.0%)and a negligible effect of environment independent of space(4.4%)at the scale of quadrats.These three components contributed 21.8,9.9 and 13.9%,respectively,at the scale of plots.The balance between the forces at different spatial scales drove community structures along the slope aspect gradient.The importance of environmental factors on b-diversity at alpine meadow increased with scale while that of spatial processes decreased or kept steady,depending on dispersal mode and abundance of species comprising the subset.But the‘pure’effect of spatial processes on species turnover increased with scale while that of environmental factors decreased.This discrepancy highlights that b-diversity and species turnover were determined jointly by spatial processes and environmental factors.We also found that the relative roles of these processes vary with spatial scale.These results underline the importance of considering species-specific dispersal ability and abundance of species comprising the communities and the appropriate spatial scale in understanding the mechanisms of community assembly.

Environmental filtering and spatial processes equally contributed to macroinvertebrate metacommunity dynamics in the highly urbanized river networks in Shenzhen, South China

Background:Disentangling the relative roles of environmental filtering and spatial processes in structuring ecological communities is a central topic in metacommunity ecology.Metacommunity ecology in the temperate river ecosystems has been well developed,while less attention has been paid to subtropical urban river networks.Here,we examined the ecological factors and seasonal difference in structuring macroinvertebrates metacommunity assembly in the subtropical urban river networks in Shenzhen,South China.Results:Our results revealed that there was no significant distinction of macroinvertebrate community composition among seasons,with only the relative abundance of Mollusca and Odonata significantly differed in both wet and dry seasons.One possible explanation was that most macroinvertebrates are generally pollution-tolerant taxa characterized with nonseasonal life cycle.In addition,distance-based redundancy analysis and variation partitioning approach revealed that metacommunity was determined equally by the environmental and dispersal-related factors.Further,our results showed that,although a slight temporal variation of relative contribution,the identity and explanation power of ecological factors were different among seasons.Specifically,stronger environmental filtering structuring community dynamics was observed in the dry than wet seasons,which might be owing to higher environmental heterogeneity under a low water-flow condition.Moreover,we detected that the influence of spatial processes was stronger in the wet than dry seasons,indicating an obvious dispersal processes due to high connectivity among sites.Conclusion:Overall,our results revealed that environmental and spatial factors equally explained variations of macroinvertebrate metacommunity,implying the necessity of considering dispersal-related processes structuring ecological communities in river bioassessment programs.Moreover,degraded habitat conditions and water quality were the predominant factors that affected macroinvertebrate communities,indicating the significance and feasibility of improving local abiotic conditions to sustain local biodiversity.Further,our findings revealed the importance of seasonal dynamics of these urban river networks in structuring macroinvertebrate metacommunity.Thereby,our study improves the understanding of ecological processes governing macroinvertebrate metacommunity and underlines the idea that community ecology studies should go beyond the single snapshot survey in river networks.

Bahadur Representation of Nonparametric M-Estimators for Spatial Processes

Under some mild conditions, we establish a strong Bahadur representation of a general class of nonparametric local linear M-estimators for mixing processes on a random field. If the socalled optimal bandwidth hn = O（｜n｜^-1/5）, n ∈ Z^d, is chosen, then the remainder rates in the Bahadur representation for the local M-estimators of the regression function and its derivative are of order O（｜n｜^-4/5 log ｜n｜）. Moreover, we derive some asymptotic properties for the nonparametric local linear M-estimators as applications of our result.