虚拟漫游系统的研究

基于软件平台MultiGen Creator和Vega开发的虚拟场景漫游仿真系统．提出了视景节点的软硬件配置要求；论述了基于Creator的实体建模方法、基于Creator建模和Vega软件环境的天空效果生成方法、声音的调用、视景仿真软件的开发过程以及整体系统的实现等关键技术．仿真结果表明，该视景仿真系统逼真地演示出在虚拟场景中漫游的的过程，并且满足系统仿真的实时性要求．     

基于MAK和Multigen Creator模型的建立

为了建立能在MAK系列软件中进行三维视景仿真的模型,以无人机模型的创建过程为例,阐述了如何利用MAK系列软件和Multigen Creator软件建模的主要方法和技巧。仿真结果表明,所创建的模型能够在MAK系列软件中得到应用,并达到了实时逼真的效果。为下一步的无人机协同作战任务规划的视景仿真提供了支撑。     

视景仿真技术在地铁列控系统中的应用

分析了地铁列车运行控制仿真系统中的三维视景子系统,探讨了基于Creator／Vega软件实现的三维视景仿真在地铁列车运行控制仿真系统中的应用,从三维视景应用的可行性、场景模型的建立、视景仿真软件设计等方面对系统进行了分析．该视景仿真系统以PC机为硬件平台,已应用于北京地铁环线基于CBTC的实验线路的研究与开发,取得很好的效果．     

基于Vega的飞行视景仿真系统设计

在飞行视景仿真的仪表建模中,专用仪表设计软件或Vega的仪表工具存在开发成本、显示效果及系统扩展性等不足。鉴于此,研究了基于Multigen Creator/Vega的复杂飞行仪表模型的建模方法,介绍了飞行视景仿真系统的模块化结构及开发该系统所用到的关键技术。在所给出的关键技术中,详细介绍了如何设计及驱动Creator软件建立的仪表实体模型以及开发基于Vega的视景驱动程序,并给出了相关的程序代码。阐述了在三维场景中,如何实现飞行模型的运动及仪表模型各模块的精确显示。该系统可以比较真实的模拟交互式的飞行过程,提供了一个通用的仿真平台。     

高速铁路视景防真系统的应用研究

介绍了视景仿真软件Muhigen Creator和Vega的特点,结合高速铁路的实际情况,阐述了利用视景仿真软件Muhigen Creator建立高速铁路三维模型及应用Vega对模型进行实时驱动的方法,分析了高速铁路仿真的应用前景,特别是在火车上的应用。     

基于HLA的航空兵场站飞行保障视景仿真系统设计

研究了应用HLA技术开发分布式交互仿真应用系统的方法,基于HLA开发工具Lab-Works、PRTI构建了航空兵场站飞行保障仿真系统的总体框架;利用建模工具MultiGen Creator、视景仿真工具Vega和VC 开发平台构建了航空兵场站飞行保障视景仿真系统,规划了视景仿真系统的各项功能单元,详细说明了视景仿真系统的工作流程与关键技术。     

基于Creator/Vega的战场视景仿真

为了建设作战仿真实验室,开发虚拟战场视景仿真系统,进行作战模拟训练,并针对以往对场景建模与管理等技术方面的不足。探讨了基于Creator／Vega软件实现战场场景建模与管理的优势及在数据格式兼容性、复杂三维模型的构建与渲染、LOD等方面存在的问题,给出了相应的解决方法实现战场视景仿真,并对关键技术作了探讨。结果表明实现的战场视景仿真系统能增加指挥人员的真实感和沉浸感,并能提高系统的渲染程度。     

Creator/Vega及其在船舶航行视景仿真系统中的应用

利用工具软件Creator、Vega来实现虚拟现实技术,介绍了Creator和Vega软件的特点,探讨了利用Cre ator和Vega软件创建实时仿真程序的过程,最后结合船舶航行仿真视景的实例介绍了基于Creator和Vega的虚拟现实技术在航海中的具体应用.仿真结果表明,基于Creator/Vega的船舶航行视景仿真系统取得了很好的效果.     

视景仿真的屏蔽门系统在地铁列控系统中的应用

研究了一种基于视景仿真的虚拟测试方法,并将其应用于地铁列车CBTC系统的仿真测试平台中,利用Multigen Creator及Vega软件构建车站、站台屏蔽门及列车的虚拟现实环境,在实验室模拟了地铁站台屏蔽门的工作,解决了CBTC系统开发工作对现场环境依赖过高的问题.     

基于Creator/Vega的空间目标视景仿真

模拟星空背景以及人造卫星动态飞行场景的真实感生成是计算机图形研究者面临的新课题,也是航天视景仿真中面临的重要任务.针对星空背景下人造卫星等空间目标的图像仿真问题,提出了一种基于Creator与Vega的动态场景生成方法.首先利用Creator绘制星体和人造卫星模型,然后根据亮星星表(BSC)利用Vega生成星空背景,并将人造卫星目标与星空背景合成,最终得到了可以任意时刻、任意角度及任意视场大小观察的空间目标动态场景.仿真结果表明,基于Creator/Vega的空间目标视景仿真取得了很好的效果,并为航天工程中小目标检测与跟踪的实时仿真提供了可行性的参考方法.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.