大型影像数据库中的色调调整方法

在详细分析造成大型影像库中色调差异成因的基础上，通过比较几种影像数字镶嵌时常采用的色调过渡匹配平衡方法，提出了一种充分考虑影像本身特征的相邻相关影像色调调整平滑过渡方法。同时为了减少大幅面影像调整时调整误差的空间传递性，给出了基于四叉树的多次调整法。     

Estimation of the time-dependent crustal movements of the zmit Earthquake

The 17 August 1999 zmit earthquake significantly deformed the earth's crust in the Marmara Region, especially in the Gölcük–Sapanca Zone, Turkey. It broke a 150-km long segment of the northern branch of North Anatolian Fault Zone. The geodetically determined moment magnitude was M_w=7.5. Global Positioning System (GPS) sites, which are a small subset of the Marmara Continuous GPS Network (MAGNET), and survey sites in the region were studied to estimate coseismic and postseismic deformations, using different methodologies with linear, quadratic and exponential kinematic models. Six GPS epochs for these sites, which were carried out before and after the 17 August 1999 zmit earthquake, were used to define the kinematic models. The quadratic deformation model was also applied to determine the time-dependent crustal movement parameters (velocity and acceleration) of the sites, using the Kalman filter technique. In order to show the differences between the models, the estimated deformation fields on the last epoch were compared. In all models, as expected, the faults near the sites show large coseismic displacements with fault parallel direction, whereas the far sites show small coseismic displacements due to the effects of the zmit earthquake. Each kinematic model, fitted to the epochs after the earthquake, shows different behaviour. While the linear model shows insufficient results, the nonlinear models (quadratic and exponential) give the best fitted to the postseismic deformations. As a result of Kalman filter analysis, the fault near-sites shows significant velocities with fault parallel direction, whereas the far sites have insignificant velocities. All stations have insignificant accelerations in the last epoch.     

Thermal history of inter-cluster relativistic electron gas heated by quasars

The thermal evolution of an inter-cluster gas of relativistic electrons heated by quasars with redshifts up toz=3 and 4 is studied in the framework of a Friedmann-Robertson-Walker universe. The gas cools by Compton scattering with the microwave backgroud radiation and by adiabatic cooling due to the universe expansion. Power and exponential laws of cosmological evolution of the comoving density of sources are considered. The obtained temperatures are sensitive to the form of these laws and to the heating epochs. Compared to the nonrelativistic models, the results obtained in the case of the power law present strong differences. These differences decrease when the exponential law is considered. Thermalization times are compared to the characteristic time of variation of the universe energy density and to the time-scales of energy loss by bremsstrahlung radiation and by Compton scattering. It is shown that, in some cases, nonequilibrium effects may be important. The time delay effects in the propagation of electromagnetic waves in cosmic plasma are shown to be very important for the analysis of theoretical models.     

Short‐term flood inundation prediction using hydrologic‐hydraulic models forced with downscaled rainfall from global NWP

A short‐term flood inundation prediction model has been formulated based on the combination of the super‐tank model, forced with downscaled rainfall from a global numerical weather prediction model, and a one‐dimensional (1D) hydraulic model. Different statistical methods for downscaled rainfall have been explored, taking into account the availability of historical data. It has been found that the full implementation of a statistical downscaling model considering physically‐based corrections to the numerical weather prediction model output for rainfall prediction performs better compared with an altitudinal correction method. The integration of the super‐tank model into the 1D hydraulic model demonstrates a minimal requirement for the calibration of rainfall–runoff and flood propagation models. Updating the model with antecedent rainfall and regular forecast renewal has enhanced the model's capabilities as a result of the data assimilation processes of the runoff and numerical weather prediction models. The results show that the predicted water levels demonstrate acceptable agreement with those measured by stream gauges and comparable to those reproduced using the actual rainfall. Moreover, the predicted flood inundation depth and extent exhibit reasonably similar tendencies to those observed in the field. However, large uncertainties are observed in the prediction results in lower, flat portions of the river basin where the hydraulic conditions are not properly analysed by the 1D flood propagation model. Copyright © 2013 John Wiley & Sons, Ltd.     

经纬仪交会测量系统的图形结构评价

以两台或多台电子经纬仪为主的交会测量系统是进行工业产品尺寸检测的重要系统设备之一,但其测量精度会受到环境条件、仪器精度、测站与被测对象的空间分布状况等的影响,尤其是测站与待测点形成的交会图形结构是影响其精度的重要因素。提出采用图形结构衰减因子(GDOP)来评价交会图形结构优劣,给出GDOP的计算方法及空间分布。通过仿真...     

利用MRF方法的高分辨率影像道路提取

高分辨率遥感影像提供了地物更丰富的信息,包括光谱信息、地物结构、形状、纹理以及地物之间的空间关系等多方面的信息。面向对象的影像分析方法以目标地物为研究对象,充分考虑目标地物的形状、结构及空间关系等信息进行目标的提取和分析,是当前高分辨率信息提取技术的主要方法。研究了采用面向对象目标的思想将MRF方法应用于高分辨率遥感影像的道路目标提取中,并进行了道路提取实验。     

Deciphering the weathering processes using environmental mineralogy and geochemistry: Towards an integrated model of laterite and podzol genesis in the Upper Amazon Basin

This article reports major results from collaborative research between France and Brazil on soil and water systems, carried out in the Upper Amazon Basin. It reveals the weathering processes acting in the partly inundated, low elevation plateaus of the Basin, mostly covered by evergreen forest. Our findings are based on geochemical data and mineral spectroscopy that probe the crystal chemistry of Fe and Al in mineral phases (mainly kaolinite, Al- and Fe-(hydr)oxides) of tropical soils (laterites). These techniques reveal crystal alterations in mineral populations of different ages and changes of metal speciation associated with mineral or organic phases. These results provide an integrated model of soil formation and changes (from laterites to podzols) in distinct hydrological compartments of the Amazon landscapes and under altered water regimes.     

Seagrass colonization: Knock-on effects on zoobenthic community,populations and individual health

This study provided evidence that Zostera noltii presence affects macrofauna community structure independently from median sediment grain-size and that the notion of ecosystem health is rather subjective: in the present case, we recorded “good health” in terms of seagrass development, “no impact” in terms of macrobenthic biotic indices and “negative effect” for a given key-population. The occurrence and development of a Z. noltii seagrass bed was surveyed at Banc d’Arguin, Arcachon Bay (France), to estimate the modification of the macrozoobenthic community and of the dynamics of a key-population for the local ecosystem, – the cockle Cerastoderma edule. Even though median grain-size of the sediment decreased only at the very end of the survey, i.e. when seagrass totally invaded the area, most of the macrofauna community characteristics (such as abundance and biomass) increased as soon as Z. noltii patches appeared. The structure of the macrofauna community also immediately diverged between sand and seagrass habitats, without however modifying the tested biotic indices (BENTIX, BOPA, AMBI). The health of the cockle population (growth, abundance, recruitment) was impacted by seagrass development. Related parasite communities slowly diverged between habitats, with more parasites in the cockles from seagrass areas. However, the number of parasites per cockle was always insufficient to alter cockle fitness.     

辽宁省岩石地球化学研究新进展

辽宁地球化学场研究,是根据辽宁全域41种元素丰度及各种地球化学参数,论述了辽宁不同地质时代和构造分区表壳岩石元素分配特点,指出了辽宁重要成矿元素的高值时代;建立了辽宁早前寒武纪变质岩、超变质岩,全域沉积岩,火成岩不同岩类的主元素地球化学模型和元素富集型式;并对Au、Pb、Zn、B等主要成矿元素的分布、分配以及与有关元素的相关特征进行了讨论;指出了成矿元素的主要载体岩石和高值地质单元。根据大地构造分区、元素组合,将辽宁全域划分为4个地球化学省,11个地球化学区,35个地球化学分区。     

PRIMARY STUDY OF SULFATE AND CARBONACEOUS AEROSOLS IN BEIJING

Results of our aerosol study, performed during 1983–1984 in Beijing, demonstrate that ambient carbonaceous aerosols are derived mainly from coal combustion. Different SO₂ oxidation processes have been observed in summer and winter. The winter sulfate appears to be produced locally and associated with products of incomplete combustion.