Internet上实时视频流传输框架的研究

论述在Internet上进行实时视频流传输的特点以及对传输带宽、延迟和丢包率的要求，研究视频传输中的应用层QoS控制方法(速率控制，错误控制)．改进了实时视频流传输的框架，在传输框架中引入代理高速缓存技术．结果表明，代理高速缓存技术能够减轻视频服务器的负载和网络拥塞，提高视频播放质量．     

面向IP网络的多视点立体视频的实时容错传输

提出了一种在IP网络上实时传输多视点立体视频的传输系统.视频流采用H.264/AVC格式编码.由于多视点立体视频庞大的数据量,系统通过2个IP信道分别进行传输.针对网络中的丢包现象,该系统采用一种新的数据包处理方法,利用各个视点之间的相关性进行丢失数据恢复.提出了一种多视点立体视频错误掩盖的算法,用来解决IP网络传输中的丢包问题.实验结果表明了该多视点立体视频传输系统的可行性.     

H.264视频流量的自适控制

多媒体在因特网络中实时传播,常因网络的带宽限制造成传输过程中数据包丢失.如何提高多媒体传输的质量是一个重要而有挑战性的任务.现提出了一种新颖的基于丢包率判决来自适应控制H.264视频流量的传输方法.实验表明该方法解决了有效带宽变化对视频传输的影响,很大程度上提高了多媒体传输的质量.     

面向无线传输的实时视频压缩编码系统设计

文章给出了一种基于帧内编码技术的实时视频压缩编码系统设计,通过对数字视频编码前分辨率、编码时帧频和压缩比的实时调整,实现具有良好抗传输丢包能力的实时低速率码流视频编码.实际系统性能验证表明,所给设计与其他现有编码技术系统相比在信道质量、带宽时变较大的无线传输应用中具有明显的优势.     

一种简单适用的带宽管理方法

本提出了一种保障实时通信瞬态信息丢失性能的带宽管理方法。本方法不依赖于无限传输连接时间、无限缓冲区等不真实的假设，且比较简单，适用于各种实时传输控制。     

流媒体应用面临的挑战及对策

流媒体数据将成为网上传输的主体，然而，目前的Internet采用的是“尽力而为”的工作方式，不承诺保证流媒体的低延时、高带宽要求．针对目前网络的低可用带宽、高丢包率、长延时、网络的动态抖动、网络和终端设备的异构性等方面，介绍了相应的解决方案，以保证流媒体应用的服务质量．     

多路现场信号调制解调技术的研究

研究了采用调制与解调方法实现多路现场信号实时传输的关键技术，设计了相应的调制与解调电路，解决了多路现场信号实时传输过程中存在的问题．通过模拟测试，电路能够满足传输精度和抗干扰性的要求．     

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。     

关于Wi-Fi网络中的冗余传输策略探究

近年来迅速发展的互联网,流行存在着多种异构的网络,跨网络多媒体的传输显得愈加重要。但是现存的互联网音频视频的传输技术都不能有效地解决各种不同网络间多媒体通信的问题,特别是IP网络的传输性能及质量。为了提高带宽网络的利用率以及视音频的传输质量,本文结合前向纠错(FEC)交织恢复丢包、冗余编码技术,依照接收端的反馈结果计算冗余包的个数,利用交织技术将原始数据与音频冗余包进行混合传输,解决了上述问题,并节省了带宽资源。     

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     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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.