基于H.264的无线局域视频通信终端的研发

为满足实时视频通信系统的连续性和传输速率,提出对视频数据进行H.264编码并通过流媒体方式进行无线传输的方案.系统采用S3C6410内部自带的硬件编解码模块MFC(Multi Format Codec)进行H.264标准的硬编码,并深入研究了H.264视频数据基于实时传输协议(RTP:Real-time Transport Protocol)的打包方式及网络传输方法,最终通过Wi-Fi网络发送到接收端,实现了C/S架构下的H.264视频传输.测试结果表明,该系统满足实时视频通信的要求,硬编码的帧率达到30帧/s,同时具有压缩比高、传输稳定等优点.     

基于H.264的无线局域视频通信终端的研发

为满足实时视频通信系统的连续性和传输速率, 提出对视频数据进行H.264编码并通过流媒体方式进行无线传输的方案。系统采用S3C6410内部自带的硬件编解码模块MFC(Multi Format Codec)进行H.264标准的硬编码, 并深入研究了H.264视频数据基于实时传输协议(RTP: Real-time Transport Protocol)的打包方式及网络传输方法, 最终通过Wi-Fi网络发送到接收端, 实现了C/S架构下的H.264视频传输。测试结果表明, 该系统满足实时视频通信的要求, 硬编码的帧率达到30帧/s, 同时具有压缩比高、 传输稳定等优点。     

基于RTP的多媒体可靠实时传输

提出一种具有QoS保证的基于RTP可靠实时媒体流的传输方案 .利用RTP/RTCP协议提供的反馈信息 ,采用调整视频发送码流的自适应算法 ,减少了码流受网络拥塞的影响 ,提高RTP流的平稳性 .并且提出FEC法和有选择重传法进行差错控制 ,有效降低丢包率 ,提高了视频的质量     

基于EWF的H.264视频流UEP传输方案

为提高H.264码流在无线传输中的鲁棒性,提出了一种基于数据分割和扩展窗喷泉（EWF）码的H.264视频的不等差错保护策略.通过H.264数据分割获取重要性不同的信息比特,采用EWF码对其进行分窗,分别采用鲁棒孤波度分布完成LT编码,实现不等差错保护.仿真结果表明,该算法具有较好的抗误码特性,可以提高重建图像的峰值信噪比值,从而保证了视频传输的可靠性.     

基于RTSP和H.264的嵌入式网络视频监控系统

本文主要介绍了基于ARM处理器S3C6410、嵌入式linux、嵌入式Live555的流媒体服务器的视频监控系统设计方案,实现了Live555对H.264压缩编码的支持、基于RTP/RTCP及RTSP协议的视频数据实时传输和基于VLC播放器的视频数据解码播放。     

实时H.264视频流的低密度生成矩阵不等差错保护

在有损网络中进行视频传输时,通常采用FEC来保护视频码流。文中提出了一种基于LDGM-UEP的实时H.264视频传输抗误码方法。发送端编码时,依据视频分组的重要性采用LDGM码对多个视频帧分组进行不等差保护,由于校验分组直接附加在数据分组之后,无编码时延。接收端对I帧直接译码,P帧只需根据子GOP中某一帧分组就可以解码显示该帧。若该帧出现误码,则不需等待子GOP中的所有分组都接收而直接对该帧进行误码掩盖,无解码时延。在接收端接收到子GOP中后续的分组后,LDGM译码器将尝试恢复出该子GOP的所有分组,防止误码扩散。实验结果表明,该方法明显优于现有的实时H.264视频通信,可提高实时视频传输的主观感受质量。     

音视频实时同步传输技术研究与实现

提出一种基于实时传输协议的音视频同步的编码方法,在同步播放的音频和视频数据之间建立起一种对应关系,在数据不同步时能迅速地找到下一个同步点继续播放.在TCP/IP网络上,基于H.264视频编解码、G.729A音频编码标准和实时传输协议RTP/RTCP,设计并实现一个音视频实时传输系统.实验结果表明,音视频同步的解决方案能...     

移动IP网络上压缩视频传输的错误弹性机制研究

随着因特网业务的增加和无线接入的快速增长,产生了大量基于无线因特网的多媒体传输的需求.第三代无线网络(3G),明确要求支持TCP/IP协议,支持在无线连接上的可视化通信.由于多径衰减和内部干扰和噪声,无线信道的误码率通常都很高.信道的误码率随着外部环境的变化而改变,这对多媒体信息传输产生破坏性影响.文章研究新一代视频压缩标准H.264/AVC的基础上,重点研究其标准的视频编码层(VCL)和网络适配层(NAL)独立的特点、错误弹性机制、率控制和率失真优化技术,提出了建立在端-端系统间联合信源编码、信道编码的自适应容错打包机制,保证视频传输的鲁棒性,仿真试验证明此方案可以改善压缩视频无线传输的鲁棒性.     

一种流媒体传输方法研究

针对H.264码流的NAL层特点提出自适应RTP组包策略,并且通过对AIMD算法的改进和优化,提高了数据流传输的平稳性.     

基于MPEG4网络实时视频传输系统的设计

在对多媒体处理技术DirectShow、媒体传输协议RTP简述的基础上，讨论了MPEG4视频流传输的RTP载荷格式。同时，设计了一种基于RTP的MPEG4视频流网络传输系统，并给出了该系统的详细结构。实践表明，该系统可以在带宽良好的局域网上较好地实现视频流的实时传输。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

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

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.