Design of an adaptive GPS vector tracking loop with the detection and isolation of contaminated channels

GPS Solutions - In vector tracking loop (VTL), the relativity among received signals is exploited to deeply integrate the entire information within signal processing channels. However, the tracking...     

HPABM: A Hierarchical Parallel Simulation Framework for Spatially-explicit Agent-based Models

A Hierarchical Parallel simulation framework for spatially-explicit Agent-Based Models (HPABM) is developed to enable computationally intensive agent-based models for the investigation of large-scale geospatial problems. HPABM allows for the utilization of high-performance and parallel computing resources to address computational challenges in agent-based models. Within HPABM, an agent-based model is decomposed into a set of sub-models that function as computational units for parallel computing. Each sub-model is comprised of a sub-set of agents and their spatially-explicit environments. Sub-models are aggregated into a group of super-models that represent computing tasks. HPABM based on the design of super- and sub-models leads to the loose coupling of agent-based models and underlying parallel computing architectures. The utility of HPABM in enabling the development of parallel agent-based models was examined in a case study. Results of computational experiments indicate that HPABM is scalable for developing large-scale agent-based models and, thus, demonstrates efficient support for enhancing the capability of agent-based modeling for large-scale geospatial simulation.     

Accuracy analysis for SST gravity field model in China

Taking China as the region for test the potential of the new satellite gravity technique, satelliteto-satellite tracking for improving the accuracy of regional gravity field model is studied. With WDM94 as reference, the gravity anomaly residuals of three models, the latest two GRACE global gravity field model (EIGEN_GRACE02S, GGM02S) and EGM96, are computed and compared. The causes for the differences among the residuals of the three models are discussed. The comparison between the residuals shows that in the selected region, EIGEN_GRACE02S or GGM02S is better than EGM96 in lower degree part (less than 110 degree). Additionally, through the analysis of the model gravity anomaly residuals, it is found that some systematic errors with periodical properties exist in the higher degree part of EIGEN and GGM models, the results can also be taken as references in the validation of the SST gravity data.     

二滩电站坝肩厂房三维有限元分析及围岩变形观测反分析

本文首先用应力函数法对二滩电站地下厂房区的着干地应力实测点进行拟合,给出了三维连续初始应力场。然后对三个大型洞室形成的厂房群进行三维有限元分析,得出了洞群围岩中破损区、应力弱化区及高应力区的分布,并就三维分析与二维分析的结果进行了对比。可以认为,二维分析不一定比三维分析更安全,因为三维分析得出的拉破裂范围更大些。文中还提出了一个用弹性有限元分析近似推求裂隙围岩破裂范围的方法。最后介绍在该现场的一个试验洞中进行围岩变形观测及反分析的结果,该反分析较好的验证了围岩力学参数及地应力测量的结果。     

Research Status and Progress of Balloon-borne Cloud and Precipitation Particles Probe

The accurate observation of the microphysical structure of cloud and precipitation plays an important role in understanding the formation of clouds and precipitation. In-situ measurement using measuring instruments carried by meteorological balloons is an effective way to obtain the microphysical properties of cloud and precipitation particles, which is a supplementary means for aircraft to observe cloud and precipitation particles. This observation method plays a more and more important role in in-situ measurement. According to the difference of the working principle of the existing balloon-borne cloud and precipitation particles probes, the detectors can be divided into particle impact-sampling sensors, particle imaging sensors, light-scattering sensors, light intensity attenuation sensors and charge measurement sensors. The working principles, key technologies and main advantages and disadvantages of typical instruments were summarized, and their applications to detailed cloud structure acquisition, cloud remote sensing method establishment, cloud and precipitation physical process research and parameterization, and scientific observation of thunderstorm clouds were briefly introduced. Finally, the development trend of balloon-borne cloud precipitation particle detectors was prospected, which will provide reference for related technical research and equipment development.     

CYLINDRICAL WAVE PROPAGATION IN LAYERED ROCK MASS

We applied the theory of interacting continua in dynamics of composite materials to study the problem of cylindrical wave propagation in layered rock mass .A set of differential equations has been derived to determine displacements and stresses in Each layer and to describe the geometrical dispersion of cylindrical wave propagation in layered rock mass .The corresponding frequency relation has been obtained .     

基于DEM的洪涝灾害信息提取与损失估算

数字高程模型(DEM)作为洪涝灾害遥感研究的辅助信息源可以提供两类信息,一是地面点的高程和所处地形部位以及与邻域的相互关系等方面的背景数据,二是研究区高程-面积关系、高程-容积关系及面积-容积关系等基本关系信息。利用这些背景数据和基本关系信息,结合洪水期遥感图像的解译,可以获取洪水淹没范围、淹没区积水量、水深、淹没历时以及作物受灾程度等灾情信息。本文阐述了这种研究的原理和方法。     

四川之春荒及其預防

四川地形,周圍高竣而中部低平,具有盆形,故有盆地之稱;東北省境為大巴山脈,高度自一千公尺至二千五百公尺,岷山山脈屹立西北邊陲,約三千至四千五百公尺之高度,西為大雪山,西南涼山,高度均不下二千至四千五百公尺,即正東川鄂界上之巫山山脈及東南方向之武陵山脈婁山山脈,皆有一千至一千五百公尺之高度,各大山脈,環立四周,愈向中心,高度愈減。盆地内部除成都平原為一眞正之平曠地形外,其(?)丘陵起伏,地面相互間之比較高度,约在一百公尺左石。     

水中目标信息智能识别方法研究

提出了基于判定准则的海洋环境下目标关系识别方法。通过HBACA算法查找或识别不同元素关系能力强的特性,提取目标信息数据的关系,之后在信息数据关系中计算每个信息节点的点度中心度、紧致中心度和节点活跃度,根据信息数据在目标事件中的重要或关键程度,将信息数据划分为关键目标信息、重要目标信息和一般目标信息。仿真结果显示:能够明确地获得关键的信息数据坐标,并与其所处事件的重要程度能够匹配,同时相关信息数据的关系非常明显,很容易提炼出所处目标事件中重要目标信息数据之间的关联。