Modeling the scale dependences of topological relations between lines and regions induced by reduction of attributes

The scale dependences of topological relations are caused by the changes of spatial objects at different scales, which are induced by the reduction of attributes. Generally, the detailed partitions and multi-scale attributes are stored in spatial databases, while the coarse partitions are not. Consequently, the detailed topological relations can be computed and regarded as known information, while the coarse relations stay unknown. However, many applications (e.g., multi-scale spatial data query) need to deal with the topological relations at multiple scales. In this study new methods are proposed to model and derive the scale dependences of topological relations between lines and multi-scale region partitions. The scale dependences of topological relations are modeled and used to derive the relations between lines and coarse partitions from the relations about the detailed partitions. The derivation can be performed in two steps. At the first step, the topological dependences between a line and two meeting, covered and contained regions are computed and stored into composition tables, respectively. At the second step, a graph is used to represent the neighboring relations among the regions in a detailed partition. The scale dependences and detailed relations are then used to derive topological relations at the coarse level. Our methods can also be extended to handle the scale dependences of relations about disconnected regions, or the combinations of connected and disconnected regions. Because our methods use the scale dependences to derive relations at the coarse level, rather than generating coarse partition and computing the relations with geometric information, they are more efficient to support scale-dependent applications.     

Definitions of natural-language spatial relations: Combining topology and directions

Because SQL for querying data from spatial databases is ineffective, the query based on natural or visual language becomes an attractive research field gradually. However, how to define and represent natural languages related to spatial data are still gigantic problems. Because existing models of direction relations can't describe by use of some common concepts. First of all, detailed direction relations are proposed to describe the directions related to the interior of spatial objects, such as “east part of a region”, “east boundary of a region”, and so on. Secondly, by integrating the detailed directions with exterior direction relations and topological relations, several NLSRs are defined, such as “a road goes across the east part of a lake”, “a river goes along the east boundary of a province”, etc. Finally, based on the NLSRs abovementioned, a natural spatial query language (NSQL) is formed to retrieve data from spatial databases.     

两次昆明准静止锋的对比分析

利用EAR5再分析气象数据,分析了两次昆明准静止锋天气过程的高低空环流形势、锋面结构、锋面位置、以及相关要素场等基本特征及其异同。结果表明：中高纬度地区阻塞形势的存在是昆明准静止锋形成的背景环流。当冷暖气团均强且势均力敌时,更有利于锋面的维持;冷空气较强时,锋面会向西移动,越过云贵高原地形的阻挡;反之,锋面则会向东移动。当锋面维持在高原地形东侧时,冷空气被地形阻挡时,锋面的移动缓慢,此时锋区最为明显。当锋面维持在地形东侧时,风场的最大水平切变、温度的最大水平梯度和相当位温的密集区,描述的锋面位置几乎相同。两次过程寒潮爆发时冷空气均只能维持到700hPa附近,且水平风场也均为600hPa以下的低空切变,说明昆明准静止锋为浅薄系统。昆明准静止锋与一般冷锋锋后不同,两次个例昆明准静止锋锋后低空为湿区,而锋前水汽是否充足则要看南支槽所处的位置。     

空间权重矩阵对空间自相关的影响分析——以我国肾综合征出血热疾病为例

应用空间自相关统计方法,分析了2008年我国肾综合征出血热（HFRS）发病率的空间分布。采用多种权重度量计算了全局和局部两种相关性指数,分析了自相关数值对空间权重矩阵的依赖性。分析结果表明：①空间距离矩阵比空间邻接矩阵能更好地度量HFRS的空间分布;②使用空间距离矩阵时,当距离阈值500km〈δ〈800km时,全国发病率数据显示出显著的空间自相关性;③从局域上看,吉林省高值显著聚集,新疆、西藏、青海、广西和海南省自身低值被高值包围聚集显著。     

高温高压下岩石弹性波速特征及其在深部地质研究中的意义

本文收集、整理、研究了７０年代以来的高温高压下岩石的Ｖｐ，Ｖｓ，Ｖｐ／Ｖｓ，Ｖｐ各向异性等实验资料后得出：（１）低压下岩石Ｖｐ的急剧变化是由岩石中裂纹与孔隙等引起的；（２）温度升高可增大由岩石组构引起的Ｖｐ各向异性的变化率；（３）同种岩石在不同的大地构造环境中具有不同的波速值与变化规律；（４）Ｖｐ在高地温区随温度先降低而后升高，其原因是由矿物相变造成的，与地壳中低速带的性质相当。文章最后讨论了实测波速转换为岩石类型时实验研究岩石波速的意义。     

我国科学数据共享现状的调查

本文是科学数据共享政策法规体系研究系列文章的收笔之作.撰写本文的目的,就是为说明科学数据共享政策法规体系的研究是建立在大量的基础调研之上.调查研究是谋事之基、成事之道.从实践中寻求解决现实问题的方法,才能制定出切实可行的政策、法规,调查研究是制定政策、法规的客观依据.为使制订政策、 规章制度适应社会经济发展和变化的新情况,就深入开展调查研究,认真听取各方面的意见,深入研究相应的管理规律和运行机制.本文详述了调查过程、调查方法,以佐证政策法规研究不能脱离实际.     

Magnetic susceptibility variations of carbonates controlled by sea-level changes

This paper presents magnetic susceptibility results of 578 samples from three Devono-Carboniferous carbonate successions in the Yangtze Block. They indicate that the magnetic susceptibility variations in carbonates are controlled by ancient sea-level changes. It is particularly so if the supply of detrital materials was low, when the magnetic susceptibility was mainly controlled by the content of authigenic minerals. If the supply of detrital materials was high, the average susceptibility value would be higher, but there is still a correlation between susceptibility and sea-level curves. A sea level rise would lead to a decrease in the content of the detrital materials, and therefore to a decrease in the susceptibility values. On the top of HST, the uplift and exposure events may lead to elevated magnetic susceptibility values. Carbonate susceptibilities can therefore be considered as one of the environmental proxy data for the research of sequence stratigraphy.     

Magnetic susceptibility variations of carbonates controlled by sea-level changes--Examples in Devonian to Carboniferous strata in southern Guizhou Province, China

This paper presents magnetic susceptibility results of 578 samples from three Devono-Carboniferous carbonate successions in the Yangtze Block. They indicate that the magnetic susceptibility variations in carbonates are controlled by ancient sea-level changes. It is particularly so if the supply of detrital materials was low, when the magnetic susceptibility was mainly controlled by the content of authigenic minerals. If the supply of detrital materials was high, the average susceptibility value would be higher, but there is still a correlation between susceptibility and sea-level curves. A sea level rise would lead to a decrease in the content of the detrital materials, and therefore to a decrease in the susceptibility values. On the top of HST, the uplift and exposure events may lead to elevated magnetic susceptibility values. Carbonate susceptibilities can therefore be considered as one of the environmental proxy data for the research of sequence stratigraphy.     

Magnetic susceptibility variations of the Ediacaran cap carbonates in the Yangtze platform and their implications for paleoclimate

Magnetic susceptibility (MS) data were obtained from 11 sections of the Doushantuo (Ediacaran) cap carbonate that directly overlies the Nantuo glacial diamictite in the southeastern margin of the Yangtze platform. The MS data revealed two regionally correlatable peaks at the bottom and top of the cap carbonate, separated by an interval of low values. The lower MS peak coincides with high percentage of insoluble siliciclastic residues that are compositionally identical to the matrix of the underlying diamictite, suggesting its origin controlled mainly by detrital components during the first phase of cap carbonate deposition at the end of the glaciation. The upper MS peak is associated with high clay content and iron sulfides, and can be interpreted as either derived from enhanced greenhouse weathering that could have brought more terrigenous components into the ocean, or the result of ocean anoxia at the late stage of cap carbonate deposition that could led to formation of abundant iron sulfides. The regionally consistent MS curves from the cap carbonates provided the first geophysical record for the rapid climate change from icehouse to greenhouse conditions in the aftermath of the Neoproterozoic “snowball Earth” event.     

济阳坳陷新生代热演化特征研究

本文综合应用镜质组反射率法和磷灰石裂变径迹法恢复了济阳坳陷新生代地温演化历史,结果表明济阳坳陷古地温梯度在新生代是逐渐降低的,其中古近纪比新近纪下降的幅度大;同时济阳坳陷内各凹陷的古地温梯度演化也存在差异,特别是古近纪末期的东营构造运动后,各凹陷的地温梯度演化差异更加明显;根据各凹陷的古热场恢复,新近纪以来东营凹陷的古地温最高,其次是沾化凹陷,惠民凹陷和车镇凹陷的古地温较低;烃源岩的生烃演化历史与其经历的古热场密切相关,古地温梯度越高的地区,烃源岩进入生烃门限的深度就越浅、时间越早。