土地类型结构格局与山地生态设计

以陕西秦岭北坡为例,进行了土地类型空间结构,数量结构和质量结构的系统分析,提出了土地类型格局的空间层次性,结构多级性和功能多元性的观点。并就区域宏观尺度进行了山地系统生态模式设计。     

基于三维图像模式识别的西藏东南部地震灾害损失风险评估

本文在对西藏东南部各县的建筑类型、数量、易损性调查的基础上,对不同类型的建筑建立了模式类向量,使用三维图像模式识别技术估计了各类型建筑在西藏东南部各县市的数量分布,建立了不同建筑物的结构易损性和人口易损性模型,并且估算了西藏东南部各县在遭遇一次设定地震时的损失分布和基于危险性的未来50年可能的损失分布情况.本文研究表明,若曲松—桑日发生7.5级地震,可能造成拉萨、山南两市较重的人员伤亡,其中曲松县和乃东区伤亡最重.西藏东南部未来50年建筑地震风险最高的地区是拉萨市区、林芝市区和错那县,其中拉萨市区的建筑财产损失风险最高.     

3D Seismic survey design using mixed-radix based algorithm inversion

The determination of three-dimensional geometry and acquisition parameters, the seismic acquisition survey design, is constantly subject of studies in obtaining data with the highest seismic quality, operational efficiency and cost minimization. In this paper, we propose a methodology for inverting geometry parameters of three-dimensional orthogonal land seismic surveys based on a direct search method using a mixed-radix based algorithm. In this algorithm, the search space is discretized on a mixed-radix base, which depends on the extreme values and the search resolution of each parameter. We will show how to reparametrize the orthogonal acquisition geometry elements in order to obtain the independents and integers parameters that are necessary to construct the mixed-radix base. For the optimization purpose, we define an objective function to contemplate target parameters associated with the elements of the acquisition geometry directly related to the geophysical and operational constraints. Taking in account that the mathematical functions and the objective function we define for the problem have no significant computational cost, all model space parameters are fast and efficiently tested. We applied the algorithm, using as input data, provided by a one-line roll orthogonal reference geometry, assuming a pair of geological objectives as shallow and deep targets. All selected models that meet both the proposed objectives and the constraints are organized by decreasing order of fitness so that with the mixed-radix inversion algorithm we found not only the best model, but also a set of suitable models. Likewise, with the best set of geometries, it is possible to establish a direct comparison between them, analysing their adherence to the technical and operational requirements according to the availability and degree of detail of each one. We show the top 10 best results as a table, allowing a direct comparison between all aspects of these geometries, and we summarize the results showing graphically the fitness of all selected geometries and the inverted geometry elements for the 1000 best geometries. These graphical displays provide a direct way to understand how each model behaves as the fitness decreases. The algorithm is very flexible and its application can be extended to any environment and type of acquisition geometry, and in any phase study of an area be it regional, exploratory or development.     

Spatial rules that generate urban patterns: Emergence of the power law in the distribution of axial line length

This paper studies emergence/generation of power law in rank-order distribution of axial line length, which is a global pattern observed in real cities, due to interaction of a set of seven simple spatial rules at a local scale. These rules and their interactions form a model expected to simulate the morphological structure of free spaces in unplanned organic pedestrian small cities. Effects of each of the seven rules are discussed through repeated simulations of eight possible combinations of the rules, using a bottom-up process. The results show that the rules generate environments with statistically stable rank-order distribution of axial line length that follows the power law. It means that the axial maps of the simulated environments have a scale-free hierarchical structure such that their distributions lean toward short axial lines. It also represents dominance of local spatial structure, as the model renders a faster rate of growth at a local scale while allowing a steady growth at a global scale.     

基于XML Web服务的地图增量更新模型研究

从地图表达数据可持续利用的角度,提出基于XML Web服务的地图增量更新模型。分析基于Web服务的地图增量更新的原理、关键技术以及实现过程,并结合GML、XSLT表达规则、SVG地图符号及JavaScript设计,实现基于XML的地图表达数据增量更新的原型系统。     

虚拟地理环境认知与表达研究初步

分析了地理学的地理环境与当前地理信息技术中的地理空间两者概念之间的差异,探讨了地图与地理信息系统空间认知的发展及特点,初步研究了虚拟地理环境认知与表达的对象、特征与主要内容。从基于虚拟地理环境的地理认知和基于地理认知的虚拟地理环境表达两个层面分析了虚拟地理环境的认知与表达;指出虚拟地理环境的认知与表达研究不仅需要进一步发展地理空间认知理论和方法,还需要拓展对地理过程及人类行为的认知与表达理论和方法研究;并着重探讨了地理过程的表达和人类行为的模拟,指出当前虚拟地理环境认知与表达研究的关键内容。     

Schwinger Bose实现下自旋相干态Wigner函数的特性分析

在Schwinger Bose实现下,引入纠缠态表象及Wigner算符在该表象下的表示,得到自旋相干态的Wigner函数,数值计算画出相空间中Wigner函数的分布图,并加以分析,发现在Schwinger Bose实现下自旋相干态确实体现出纠缠特性.