Iterative Decoding of Parallel concatenated Block Codes and Coset Based MAP Decoding Algorithm for F24 Code

A multi-dimensional concatenation scheme for block codes is introduced.in which information symbols are interleaved and re-encoded for nmore than once.It provides a convenient platform to design high performance codes with flexible interleaver size,Coset based MAP soft-in/soft-out decoding algorithms are presented for the F24 code.Simulation results show that the propsed coding scheme can achieve high coding gain with flexible interleaver length and very low decoding complexity.     

BCH—LT级联码的分析与设计

通过把无码率LT码和BCH码进行级联,构造了一类性能优异的级联码,并且提出了软判决迭代译码算法,应用在内外码的译码过程中,解决了错误平层问题。通过仿真可知,在加性高斯白噪声二进制对称信道中,该级联码在很宽的信噪比下具有较好的性能,可以进行可靠的传输。     

一种基于超立方体图的Hadamard矩阵构造法

Hadamard矩阵是一种十分特殊的正交矩阵。它在区组设计、数据压缩、数字图象处理、数据挖掘、信息安全、通信理论、量子计算、编码理论等诸多领域有着广泛的应用。然而,Hadamard矩阵的构造问题至今仍是一个悬而未决的问题。本文针对该问题提出了一种新的Hadamard矩阵构造法,并通过具体实例展示了本文所提出的方法的可行性。     

新型的近仙农理论极限码:之型码和级联之型码

This paper introduces a family of error-correcting codes called zigzag codes.A zigzag code is described by a highly structured zigzag graph.Due to the structureal properties of the graph,very low-complexity soft-in,soft-out decoding rules can be implemented.we present a decoding rule,absed on the Max-Log-APP(MLA) formulation,which requires a total of only 20 addition-equivalent-operations per information bit per iteration.Simulation of a rate-1/2 concatenated zigzag code with four constitutent encoders with interlezer length 65536 yields a bit error rate(BER) and of 10^-5 at 0.9 dB and 1.4dB away from the Shannon limit by optimal (APP) and low-cost sub-optimal(MLA) decoders,respectively.     

关于稳定矩阵Kronecker积与Hadamard积的一些性质

讨论了稳定矩阵Keroncker积与Hadamard积的一些性质,得到了某些类型稳定矩阵的Ker-onecker积与Hadamard积是稳定矩阵的一些条件。     

关于Hadamard乘积行列式下界的注记

指出了LI Yao-tang and ZHONG Cong-lei("Some estimations for determinant of the Hadamard product of H-matrices","Journal of Computational Mathematics",2005,23(4))得到的关于两个H-矩阵的Hadamard乘积的行列式的一个下界和陈神灿("Some determinantal inequlities for Hadamard product of matrices","Linear Algebra Appl",2003,368)的结论是等价的。应用置换相似下的Hadamard乘积的行列式的不变性,给出了较大的一个相应的下界。     

阶数n〉4的Hadamard矩阵不是循环矩阵的完整证明

从Hadamard矩阵和循环矩阵元素的一些性质出发,根据阶数n〉4的Hadamard矩阵中元素＋1与-1个数的存在情况,证明了这个Hadamard矩阵不可能由循环矩阵生成．所以,阶数n〉4的Hadamard矩阵不可能是一个循环矩阵．     

一种新的序贯软输出维特比算法(英文)

本文针对含有级联译码或级联均衡译码的接收机提出了一个新的软输出维特比算法，该算法克服了传统算法中系统性能、时延和运算量之间的矛盾，在获得运算量和时延有较大下降的同时，保证了系统性能     

Word processing in dyslexics

Dyslexic children (n=21, mean age=10.2 years) were compared with normal readers of the same age, normal readers of the same reading-age, and poor readers of the same reading-age on measures of phonological decoding and automatic word processing. Three different tasks, varying in phonological demand, were used: a naming task, an auditory-visual matching task, and a lexical decision task. On each task, word-pseudoword profiles were obtained to test phonological decoding skills and unspeeded-speeded profiles were assessed to test automaticity in word processing. Main results indicated that dyslexics have a deficit in automatic phonological decoding skills. The results are discussed within the framework of the phonological deficit and the automatization deficit hypothesis.     

关于一类含有线性算子的亚纯多叶函数

引进和研究了一类含有线性算子的新的多叶亚纯函数,得到了这一函数类中的一些有趣性质,如包含关系、卷积性质等．这些结果改进和拓展了早期的一些工作,同时也得到了其他一些新的结果．     

三对角M矩阵的Hadamard积的最小特征值下界估计式的研究

研究了三对角M矩阵B和三对角M矩阵A的逆矩阵A-1的Hadamard积的最小特征值q(B°A-1)界的估计问题,利用A-1的元素新的上界估计式给出了q(B°A-1)新的估计式.若A=B,得到q(A°A-1)新的估计式.     

Paths to reading comprehension in at-risk second-grade readers

Two studies of second graders at risk for reading disability, which were guided by levels of language and functional reading system theory, focused on reading comprehension in this population. In Study 1 (n = 96), confirmatory factor analysis of five comprehension measures loaded on one factor in both fall and spring of second grade. Phonological decoding predicted accuracy of real-word reading; automatic letter naming predicted rate of real-word reading; accuracy and rate of both real-word reading (more so than decoding of pseudowords) and text reading predicted reading comprehension; and Verbal IQ also predicted reading comprehension. In Study 2 (n = 98), the treatment group (before/after school clubs receiving an integrated instructional approach that was supplementary to the general reading program) improved significantly more in phonological decoding and state standards for reading fluency than the control group (general reading program that had some code instruction but emphasized comprehension). The rate of phonological decoding explained 60.3% of real-word reading. Both treatment and control children improved significantly in reading comprehension, but controlling for pretreatment individual differences in oral vocabulary or in phonological decoding eliminated this effect. Taken together, the results of the two studies support two paths to reading comprehension: one from vocabulary and verbal reasoning, and one from written language that has multiple links between subskills: (a) alphabetic principle --> phonological decoding, (b) automatic phonological decoding --> accurate real-word reading, (c) automatic letter coding ---> automatic word reading, and (d) automatic word reading --> fluent text reading. Instructional implications of both paths and the links within the written language are discussed.     

弱Hadamard积的行列式下界估计的0ppeheim不等式

指出按通常的复数域或实数域上的方式来定义实四元数体上的矩阵的Hadamard积,在这样的乘积下正定自共轭四元数矩阵是不封闭的。给出了半正定自共轭四元数矩阵与半正定自共轭实矩阵的弱Hadamard积的行列式的下界估计。     

Hadamard不等式的应用与推广

应用Hadamard不等式及一些相关的凸函数不等式可以在调和平均值、几何平均值、算术平均值之间再插入其它的数,构成新的不等式,并给出Hadamard不等式在一元情形下的一个推广。     

Phonological awareness tasks as predictors of decoding ability: beyond segmentation

The performance of 38 male third- and fourth-grade reading disabled/poor decoders and above-average readers/good decoders was compared on a series of six measures of phonological awareness, including tasks that required the ability to segment, blend, and manipulate phonemes. Performance on these tasks was also correlated with phonetic decoding of pseudowords. Significant but varying intercorrelations were obtained among tasks in both groups. For the poor decoders, deletion was the most highly correlated with the other tasks. However, all good decoders performed at ceiling level on this task. For the poor decoders, deletion was significantly correlated with phonetic decoding (r = .74 and r = .78 for timed and untimed decoding measures, respectively). While all good decoders had good phonological awareness, not all those with good phonological awareness were good decoders. The results suggest that tasks that require blending and manipulation of phonemes, in addition to segmentation, may predict decoding ability best.     

多频带UWB通信系统中低复杂度迭代差分译码算法

相对于相干检测,由于在收发端不需要信道状态信息,非相干UWB通信在信噪比方面会有近3dB的性能损失.为了克服这一性能差距,提出了一种有效的基于多频带UWB系统的差分编译码方案.该方案在发射端使用2个并行级联的递归酉差分空频编码器对数据进行编码.接收端的2个分量译码器通过互相交换软度量值对数据进行译码.为了降低接收机的计算复杂度,给出一种只使用转移概率计算信息比特似然比的译码算法.仿真结果表明,在较少迭代次数下,算法性能远优于传统非相干检测,在高信噪比时,其性能甚至超过了相干检测.     

A meta-analysis on the effectiveness of phonics instruction for teaching decoding skills to students with intellectual disability

This meta-analysis examines the effects of phonics instruction on the decoding skills of students with intellectual disability using a random-effects model. Eight single-case experimental studies and six experimental or quasi-experimental group studies met the inclusion criteria, encompassing a total of 297 participants with intellectual disability. The overall effect of phonics instruction on the decoding skills of persons with intellectual disability was large: g = 1.42 (95% CI: 0.75, 2.10). Single-case studies yielded a larger average effect size (g = 1.94, 95% CI: 1.10, 2.78) than group studies (g = 0.41, 95% CI: 0.13, 0.69). Researcher-designed tests also yielded larger effect sizes than standardized tests. The type of interventionist was not a significant moderator. In the majority of the studies, phonics instruction was carried out using a systematic and direct instruction approach and a one-to-one format. Implications for practice and research are presented, and areas that require further investigation are identified.     

一维奇异积分的主值分析

给出了奇异积分的Cauchy主值与 Hadamard主值的定义,并得到其在主值意义下的表达式.     

逆M-矩阵与正定矩阵Hadamard乘积行列式的下界

首先改进了用于实对称正定矩阵的Hadamard乘积的行列式的下界估计的经典的Oppenheim不等式的加强形式,然后应用这个结论和逆M-矩阵的性质,得到了实对称正定矩阵和逆M-矩阵的Hadamard乘积的行列式的新下界估计。     

An Examination of a Small‐Group Decoding Intervention for Struggling Readers: Comparing Accuracy and Automaticity Criteria

In this study, we compared methods to improve the decoding and reading fluency of struggling readers. Second‐grade poor readers were randomly assigned to one of the two practice conditions within a repeated reading intervention. Both interventions were in small groups, were 20–28 min long, took place 2–4 days per week, and consisted of phonemic awareness training, letter sound practice, and practice in word families. Students in the accuracy condition (n= 27) practiced each page until they reached 98 percent accuracy while students in the accuracy + automaticity condition (n= 29) practiced until they reached rate (30–90 cwpm) and accuracy criteria. Hierarchical linear modeling revealed no differences between practice conditions in decoding accuracy, reading comprehension, and grade‐level text reading fluency. Significant differences favoring the accuracy + automaticity group were found in measures of decoding automaticity.