一种基于整数操作的极化码最小和译码算法

通过信道极化,极化码理论上证明可渐进达到香农限。文中研究极化码在高斯信道下的串行抵消(successive cancellation,SC)译码算法,提出了一种基于整数操作的最小和译码算法。算法中信道输出值被均匀量化后再取整数,作为SC译码器的输入;节点更新使用最小和算法,更新过程不需要量化操作,直接使用信道输出值量化后的整数值。数值仿真结果表明,在信噪比小于4 d B时,译码性能与基于浮点运算的原始SC译码一致;当误比特率为10-5时,提出的算法与原始SC译码的信噪比相差0.2 d B。所提出的算法便于硬件实现,运算中变量的大小都用8比特整数表示。     

改进的低复杂度BP译码算法

基于对数似然比的BP译码算法与标准BP译码算法相比,降低了一定的运算量,但仍具有较高的计算复杂度,硬件实现时需要消耗较高的资源。针对此问题,提出了一种变量节点动态更新选择的对数似然比BP译码算法,根据每一次迭代后变量节点外信息的收敛情况及校验方程的满足情况,动态地选择置信度最低的部分节点参与更新,其他置信度较高的节点则不进行更新。仿真结果显示,该算法译码性能与对数似然比BP译码算法相比,在0.5码率,10-4误码率时,1 024码长有0.1dB的性能损失,2 048码长性能损失仅有0.07dB,但从第4次迭代开始归一化运算量至少降低了50%。     

低密度奇偶检验码译码的高效量化算法

为降低低密度奇偶检验码译码的硬件实现复杂度,提出了一种可变步长均匀量化"和积"译码算法。该算法分为两步进行:首先,检验节点和变量节点的外信息都以相同的量化步长进行均匀量化而进行迭代译码;然后,当迭代达到预定的次数时,检验节点和变量节点的量化步长分别乘以和除以预先选定的一个参数。仿真和现场可编程门阵列实现结果表明,与未量化的标准积译码算法相比,该算法的性能损失在0.1 dB以内;与同等性能的算法相比,该算法可以降低50%的硬件规模。     

基于RMP调度的简化差分域LDPC译码算法

针对对数域和积LDPC（Low Density Parity Check Codes）译码算法复杂度高和译码采用的SMP（Standard Message Passing）调度算法收敛速度慢的问题,提出基于RMP（Row Message Passing）调度的简化差分域LDPC译码算法.用RMP调度优化变量节点信息更新使收敛速度提高一倍.由于在Tanner图上传递的是概率的差分值,并且在校验节点信息更新时选择w个绝对值最小的差分值进行,降低了算法复杂度.实验表明本文算法在不降低译码性能条件下降低了算法复杂     

基于量化修正的低复杂度LDPC译码算法

为进一步降低基于可靠度的(Low Density Parity Check,LDPC)译码算法复杂度,提出一种基于量化修正的低复杂度LDPC译码算法,该算法在对信道信息预处理时引入量化信息修正处理策略,从而避免在译码迭代过程中进行译码信息修正处理操作,在保持译码性能的同时,较大幅度地降低译码复杂度。针对均匀和非均匀量化方案,本文实现了基于修正系数的均匀量化和基于列重修正的非均匀量化两种译码方案。仿真实验结果表明,所提出的两种译码方案在算法复杂度明显较低的情况下,仍然与MRBI-MLGD译码算法具有相同的译码性能与收敛速度。特别地,在基于列重修正的非均匀量化方案中,只需3-4 bits的低比特量化即可达到均匀量化中高比特量化(8 bits)相同的迭代次数和误比特率性能。     

一种低功耗架构下毫米波信道估计算法研究

针对低分辨率模数转换器量化误差大、信道估计准确性低等问题,提出一种两阶段信道估计算法。利用量化过程构造优化问题,采用梯度下降算法估计支撑集;根据估计的支撑集将信道估计问题降维;采用最大化期望算法降低量化误差并估计信道复增益。仿真结果表明,提出的算法比目前最先进的对比算法性能提高了6 dB,且时间复杂度由对数线性数量级降为线性数量级。     

非规则LDPC码译码改进算法及其DSP实现

为了降低非规则低密度奇偶校验(low-density parity-check,LDPC)码译码算法的复杂度,提出一种适合数字信号处理器(digital signal processor,DSP)实现的低运算复杂度、低误码平台译码的改进算法。该算法校验节点的运算采用修正最小和算法,外信息的更新采用串行方式,既保持了串行和积算法在有限迭代次数下译码门限低的优点,又降低了节点运算复杂度和误码平台。用定点DSP芯片实现的非规则LDPC码译码器的实测结果表明,该算法能以较低的实现复杂度获得低的误码平台和译码门限。     

非规则LDPC码译码改进算法及其DSP实现

为了降低非规则低密度奇偶校验(low-densityparity-check,LDPC)码译码算法的复杂度,提出了一种适合数字信号处理器(digitalsignalprocessor,DSP)实现的低运算复杂度、低误码平台译码的改进算法。该算法校验节点的运算采用修正最小和算法,外信息的更新采用串行方式,既保持了串行和积算法在有限迭代次数下译码门限低的优点,又降低了节点运算复杂度和误码平台。用定点DSP芯片实现的非规则LDPC码译码器的实测结果表明,该算法能以较低的实现复杂度获得低的误码平台和译码门限。     

基于新迭代策略的IRA码改进译码算法

IRA码的译码通常采用BP译码算法,然而BP译码算法复杂度高,硬件电路实现困难。最小和译码算法虽然降低了运算复杂度和硬件实现难度,但是其牺牲了部分译码性能。五线段近似算法对BP算了做了近似简化,然而其复杂度依然偏高。提出了一种基于五线段近似和最小和的改进译码算法,在降低系统译码复杂度的同时,保持较高的译码性能。仿真结果表明,改进的译码算法在降低了复杂度的情况下,仍能得到较高的译码性能。     

一种简化的低密度校验码译码算法的研究

针对低密度校验码(LDPC)译码的迭代过程的复杂度问题，提出一种新的简化的译码算法，通过对每次迭代中校验节点的更新变换之后计算的线性拟合，来降低计算的复杂度，从而加速译码。计算机仿真结果显示，简化的译码算法与传统的和积算法相比，译码性能基本接近，有时要稍差一些，但译码复杂度是有明显的下降的，这样即证明了方案的有效性。     

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.     

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.