低信噪比下的并行多延时相关帧同步算法

为提高正交频分复用(OFDM)在低信噪比环境下的同步性能和抗噪能力,提出了一种并行多延时相关帧同步算法。该算法充分利用帧的前导训练符号周期重复的特点,在接收端滑动窗中并行处理多种延时相关运算,通过阈值判决进行帧检测,同时完成载波频率同步,进而实现OFDM帧同步。该算法无须改动现有系统的物理帧结构,也不增加系统延时。理论分析和在加性G auss白噪声信道下的误帧率(FER)性能仿真证明:该算法的误帧率约为现有参考方案的1/10,信噪比(SNR)比参考方案提高约7 dB,能够工作在信噪比小于-1 dB的环境。     

GPS/INS延时估计与基于残差重构的延时补偿算法

传感器采样延时是多传感器信息融合过程中面临的一个重要问题,全球定位系统/惯性导航系统(GPS/INS)的组合导航系统是智能汽车常用定位方式,但常面对GPS采样延时的问题,因而会造成对INS误差状态的错误估计,影响定位定速的精度.本文针对该问题,在传统的GPS/INS松耦合组合导航模型的基础上提出一种延时估计和补偿的算法.首先建立延时估计模型,估计时间同步误差,然后构建残差传播方程,利用残差重构的方式进行延时补偿,实现基于软件的时间同步.根据试验中对速度、位置误差及均方根误差的分析,改进的滤波算法有效地降低了GPS采样延时引入的误差,提高了定位和定速的精度.     

音视频同步压缩编码算法

为了更好地解决音频与视频同步问题,提出了一种嵌入式音视频混合信号同步压缩编码算法。在发送端将音频信号作为隐藏信息,嵌入视频图像的DCT(Discrete Cosine Transform)系数中,然后对嵌入了音频信号的视频信号进行压缩编码,在接收端从视频信号中提取出音频信息,再对音频和视频信号进行重构,得到恢复后的音频与视频。该方法在不增加音频和视频压缩数据量,同时保证音频和视频主观质量没有明显降低的情况下,实现了音视频信号同步压缩。     

基于漏桶算法的自适应多媒体同步控制机制

针对分组交换网中多媒体通信的动态特性,借助实时传输协议(RTP),在接收端对网络延时进行了估计,并及时了解网络负载的变化,进而根据漏桶算法,自适应调节和维持多媒体同步,以保证多媒体服务质量.仿真实验表明,这种同步控制机制能够适应不同的网络环境,效果良好.     

基于 GPS 的全网同步时钟的建立和误差校正

分析基于ＧＰＳ（全球卫星定位系统）技术提供的高精度时间建立电力系统全网同步时钟时可能产生的误差和延时的各个环节、产生原因及数量级，并研究减小或避免各种误差或延时的技术手段。ＧＰＳ时间信息的引入及处理和数据的采集及传输过程均可能对同步时钟造成一定的误差和延时。延时的影响可以通过精确的测量和分析进行补偿，误差项是降低时钟精度的主要原因，只能通过设计和算法优化尽量减小。经补偿和优化后所得到的同步时钟的精度为２μｓ。     

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...     

基于嵌入式前端服务器的音视频监控系统设计

采用TMS320DM365多媒体处理器设计并实现了一种集音视频采集、编码、压缩、本地存储、RTP/RTCP,RTSP传输的嵌入式前端服务器.该监控系统在PC或者Android系统的PDA上实时接收并播放音视频流,实现了音视频实时监控;可用于小型企业安防,智能家居等监控领域.经VLC播放器统计信息中音视频丢帧数统计测试,音视频还原流畅,同步效果良好.     

一种适合IEEE802.16m的改进前导字结构和定时同步算法

结合IEE802.16m协议分析了定时同步误差对系统性能的影响.通过对同步训练序列及传统定时同步算法的分析,提出了一种适合IEEE802.16m系统的定时同步方案.该方案利用训练序列的相关性,通过改进前导字结构及同步算法实现接收端的定时同步.在高斯信道和SUI-3信道下进行了仿真.结果表明,改进的定时同步方案优于传统方...     

一种适合IEEE802.16m的改进前导字结构和定时同步算法

结合IEEE802.16m协议分析了定时同步误差对系统性能的影响。通过对同步训练序列及传统定时同步算法的分析,提出了一种适合IEEE802.16m系统的定时同步方案。该方案利用训练序列的相关性,通过改进前导字结构及同步算法实现接收端的定时同步。在高斯信道和SUI-3信道下进行了仿真。结果表明,改进的定时同步方案优于传统方案,具有良好的性能,且易于实现。     

电力系统中基于SDH的时间同步系统研究

针对电力系统中的时间同步问题,提出一种基于SDH的时间同步系统设计方案。通过对比目前常用的时间同步系统方案,选择电力系统中最成熟的SDH网络作为时间同步系统的媒介,提出一种时隙校准时间同步算法(TSA),并给出具体的设计方案。该算法中,主从设备在SDH的E1某个时隙bit位发送时间信息,并记录传输延时,从设备利用主设备提供的延时信息得到通道延时差,然后利用延时差校准从设备的时间,实现时间精确同步。通过理论分析,该算法可以达到ns级的时间同步精度。     

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.     

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.     

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.     

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.