36军官极值问题多重解

本文定义了广义Euler方阵及其计数,研究了一类六阶广义Euler极值问题的多重解。它的背景是著名的36军官问题。所得的结果可用于六元编码的设计。     

(Mis)Understanding underachievement: a response to Connolly

In British Journal of Sociology of Education Volume 29 number 3, 2008, Connolly presented what he termed a ‘critical review’ of some of our previous work on the relative attainment of male and female students in UK schools. He proposed three general areas for criticism – our use of attainment gaps, our consideration of outcomes other than at specific thresholds, and our querying of the idea of student ‘underachievement’. These problems, he claimed, have ‘given rise to a number of misleading conclusions that have questionable implications for practice’. However, those of his ‘criticisms’ with any merit are actually the same as our own conclusions, transmuted by Connolly from our papers that he cites, while his remaining ‘criticisms’ are based on faulty elementary logic. In case readers have not read our work and were somehow misled by Connolly, we give here a brief reply to each criticism in turn. This matters, because a greater understanding of patterns of attainment and of the nature of underachievement is a precursor to the design of successful initiatives to overcome inequalities in educational opportunity and reward. This is both a practical and an ethical issue.     

基于Turbo码的比特级联合信道安全编译码

联合信道安全编码将信道编码作为加密系统实现了纠错与加密的合二为一.本文采用基于密钥控制随机删余的Turbo码来实现联合信道安全编码.针对目前普遍采用的Turbo码迭代译码方案计算量大、译码延时长和功耗大的问题,采用一种新的比特级迭代译码算法,结合编码时的加密删余信息,对未收敛比特在一个小窗口内进行部分迭代以减少已收敛比特的不必要迭代,从而减少总体迭代次数和计算量.实验表明本方案可在保障通信可靠性和安全性的基础上进一步降低译码开销,提高译码效率.     

均值不等式及其推广

着重讨论了均值不等式及其应用,同时给出均值不等式的一个推广.