5次交错群A_5的10阶子群的一个构造方法

A5的元最大阶数是5,使用有限群的Lagrange定理,A5的10阶子群元的阶只可能是2,5。但由于拉格朗日定理的逆不成立,因此是否存在A5的10阶子群仍是问题。该文通过对5-循环置换各次方幂的计算及其研究,找到A5的10阶子群元的构成规律,并使用构造性方法给出了5次交错群A5的6个10阶子群。     

The Read Feed: Reviews

Abstract

Michelle DeMars reviews Academic Libraries for Commuter Students: Research-Based Strategies. Hayley Moreno reviews Coding with XML for Efficiencies in Cataloging and Metadata: Practical Applications of XSD, XSLT, and XQuery.     

母语在藏族大学生识记中的作用

通过对藏族大学生在识记不同语言材料时表现出不同效果的分析,从信息加工的角度阐述了母语是识记的基础,是识记表象建立的关键,母语所反映的认知取向决定了识记的侧重点。     

蒙台梭利儿童饮食生活教育的扎根研究

当今国内对蒙台梭利的研究更多体现在宏观层面,而专门对饮食生活教育的研究较少受到关注,特别是缺乏“深描”性质的质化研究。鉴于此,研究者以6部蒙台梭利教育论著作为“访谈”对象,采用非交互性资料收集方式,深度挖掘文献资源,通过三级编码发展出蒙氏儿童饮食生活教育的扎根理论。研究发现,蒙氏儿童饮食生活教育思想体系包括饮食营养的价值追求、食物的来源及处理、儿童饮食行为的发展、饮食生活教育过程等4个理论构念,其中包含健康功能、健康权利、健康卫生、食品制作、食物选择、饮食文化、发展需求、发展阶段、营养因素、行为练习、饮食调控、教育误区等12个触发式概念。蒙氏饮食生活教育也是一个调节儿童与食物主客交互并具有积极价值追求的实践体系,对于当今儿童健康教育现实具有极强的指导意义。     

基于DirectX的气象雷达实时显示技术研究

提出了一种在Windows操作系统下的图像实时显示新型方法,该方法充分应用DirectX的更好的兼容性和更有效的图形加速特性,使用多缓存区进行图像数据存储、实时插值和边缘平滑处理、绘画和页面翻转的技术.以上技术使得气象回波的PPI和RHI显示更逼真地复现了天气的实时变化情况,并且显著地改进了系统的实时处理性能.实验结果证明了使用该技术的有效性和可行性.     

Book Reviews

Critical appraisal of research studies forms a central role within the application and uptake of evidence‐based approaches within health and social care. While there are established checklists for evaluating quantitative research, this is not the case for qualitative research. This article outlines the process of developing an evaluative tool for qualitative studies, reflecting the uniqueness of the associated paradigm, and illustrates its use by reference to three qualitative research papers appraised within a systematic review of community‐based rehabilitation services. At its centre are concerns with the context of the study and the way the data are collected and analysed. Use of such an evaluative template opens the way for the quality of qualitative research to be judged in a systematic manner and for qualitative research to take its rightful place within debates over what works, where, when and how within health and social care policy and practice.     

DCT域分形图像压缩编码方法

首先研究了一般分形图像压缩方法存在的缺陷，然后对它进行改进。最后在ＤＣＩ域做进一步的改进。实验结果表明，和原来方法相比较，ＤＣＴ域分形图像压缩编码方法具有明显的优越性。     

On Combinatorial Approximation of Covering 0-1 Integer Programs and Partial Set Cover

The problems dealt with in this paper are generalizations of the set cover problem, min{cx | Ax b, x {0,1}ⁿ}, where c Q₊ⁿ, A {0,1}^{m × n}, b 1. The covering 0-1 integer program is the one, in this formulation, with arbitrary nonnegative entries of A and b, while the partial set cover problem requires only m–K constrains (or more) in Ax b to be satisfied when integer K is additionall specified. While many approximation algorithms have been recently developed for these problems and their special cases, using computationally rather expensive (albeit polynomial) LP-rounding (or SDP-rounding), we present a more efficient purely combinatorial algorithm and investigate its approximation capability for them. It will be shown that, when compared with the best performance known today and obtained by rounding methods, although its performance comes short in some special cases, it is at least equally good in general, extends for partial vertex cover, and improves for weighted multicover, partial set cover, and further generalizations.     

试论发达地区加快实现社保全民化的策略

加快实现社会保险全民化是推动社会保险事业持续快速发展,构建社会主义和谐社会的重要手段。针对困扰先发地区社会保险全民化发展的政策、经济和社会因素,此文以推进社会化管理为突破口,以机制建立为有效保障,对实现社保全民化的策略进行了一些探索。     

基于Haar小波变换的无失真图像压缩

提出了一种利用Ｈａａｒ小波进行图像无失真压缩的算法。对线性预测后的图像进行Ｈａａｒ小波分解，将各子带小波系数根据大小分解成两部分，其位置信息分别通过自适应算术编码进行了有效的压缩。试验结果表明，该算法实现简单，达到了很好的压缩效果。