多站点远程实时视频传输与控制系统

为了实现远程监控图像的清晰,并保障系统的实时性和可靠性,需要高效率和高质量地进行视频压缩,无差错地进行快速网络传输,有效地进行命令控制.通过优化最新的H.264视频编码算法,设计有效的传输方案和引入自适应的传输机制来解决远程活动图像传输系统中存在的清晰、实时、高效、可靠性问题.实验结果表明: 改进后的算法较原有的T.264编码方案速度提高了30%以上,设计的传输策略在保障传输速度的同时,能有效地适应不同的网络环境.在系统中引入的几个关键技术对远程视频传输系统提供了有力的支持.     

视频流自适应传输框架的设计与实现

针对网络视频应用交互性、实时性、突发性、数据量大等特点,设计并实现一个基于RTP/RTCP的端到端的视频流传输框架. 通过反馈控制协议自适应地调整视频传输码率,提高视频应用的服务质量并达到对网络带宽的高利用率. 测试结果表明在网络状况波动的情况下,视频流自适应传输框架具有较高的网络利用率和较低的包丢失率.     

远程机器人监控系统的研制

提出了利用Internet实时传输现场图像和发送控制命令的远程机器人监控系统的设计思想和总体结构。由于对实时性要求高 ,传输的视频图像数据量大 ,该系统采用了最新的视频图像压缩编码技术MPEG - 4。此外 ,采用TCP协议和RTP协议的联合使用技术 ,从而提高视频数据在网络中的传输质量与传输速度。实验证明 ,该监控系统既保证了控制命令传输的可靠性 ,又保证了机器人现场图像传输的实时性。     

基于视网膜中央凹视觉的生产监控图像处理方法

在面向生产现场的远程视频监控系统中,视频图像的庞大数据量与系统的处理能力和网络带宽条件往往容易形成冲突,而繁杂冗余的现场视觉信息也难以符合生产监控的需求。该文提出了一种基于视网膜中央凹视觉的生产监控图像处理方法,从生产监控的特点和需求出发,模仿人眼的视觉感知特性对视频图像进行空间变分辨率转换,从而降低数据量并实现对监控效用信息(MEI)的筛选。实验结果表明,该方法能够帮助远程视频监控系统有效降低视频传输码率,在保证系统实时性的同时提高了生产监控的效率。     

网络会议中视频传输的实时性控制策略

在网络环境下的远程视频频会议过程中,视频数据传输的实时性非常重要,而日益拥挤的网络使其实时性越来越难以保障.本文构建了视频传输模型,提出了随网络状态的变化而适时变化视频数据的采集速率,从而保证视频数据传输实时性的控制策略.     

嵌入式Linux飞行器视频采集与处理模块设计

为提高微型飞行器无线视频的传输距离及传输质量,选用S3C2440微处理器为控制中心、OV9650摄像头为移动端视频采集设备,给出了视频采集与处理模块的总体设计方案和硬件结构.模块开发基于嵌入式Linux平台,设计并实现了遵循V4L2(Video For Linux 2)驱动标准的移动端视频采集模块、基于H.264的视频编解码模块以及适用于3G/4G的无线网络通信模块,其中无线通信采用RTP协议,以满足视频无线远程传输的实时性要求.结果表明,该系统传输的视频满足清晰、稳定与延时低的要求,具有一定的实用前景.     

基于TMS320DM642芯片的MPEG4SVP视频编码的实现

本文在TI公司的TMS320DM642芯片上实现了MPEG4SVP算法,并针对DSP硬件系统对算法进行了优化,实现了系统的实时性,可应用于实时视频监控以及远程视频图像传输等多方面.     

延迟受限细粒度可伸缩视频流媒体的平滑传输

对于异构网络上可伸缩视频的传输,为了解决由于网络的时变性特征所引起的编码码流与网络带宽不适配所引起的问题,提出了一种控制可伸缩码流的传输,使之适应带宽的时变特性,同时能够保证平滑的重建视频质量的传输调度算法。在延迟受限的条件下,通过控制每一帧增强层码流的传输,使得带宽变化所带来的视频质量波动显著下降,从而有效地提高了视频的总体质量。仿真试验表明,该方案在提高视频客观质量的同时提高了其主观质量,有效提高了视频传输的鲁棒性。同时,所提出的算法复杂度较低,能够应用在实际的流媒体传输系统中。     

基于IP组播视频会议系统的研究与实现

为了解决IP网络上多媒体通信领域的带宽资源缺乏问题,论述了视频会议系统的设计及系统实现过程中关键技术的解决方案。提出了采用IP组播方式传输视频流,以节省网络带宽;参照H.332协议设计该系统终端与终端之间的通信机制;使用DirectShow技术处理每个客户端之间的视频数据交互,并开发了网络视频流传输Filter。测试结果表明,使用组播传输有效地节省了网络带宽,系统具有很好的规模扩展性。     

嵌入式数字家庭安防视频采集系统设计

针对安防监控系统中视频采集的需求,设计了嵌入式视频采集系统.采用ARM/DSP双核协同工作方式,其中ARM采用三星的ARM微处理器S3C2440,主要实现网络传输和控制功能;DSP采用专用于视频处理的芯片TMS320DM6437,对视频流进行压缩处理,两者通过DSP的主机接口进行通信.网络传输基于RTP协议,根据网络状态调节编码传输速率自适应网络带宽,实现面向服务的QoS控制.实验表明,系统具有成本低、稳定性和实时性好、易于扩展等优点,可用于数字家庭等场所.     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.