美国ETF市场的发展及对我国的启示

ETF是一种可同时在一级市场和二级市场交易的消极管理型指数基金,它的许多优点使其近年来在全球各大主要资本市场上获得了迅猛的发展。我国也已于2004年11月29日推出第一支ETF——上证50ETF,因此了解并借鉴美国这一世界上最为发达和成熟的ETF市场的发展经验将对我国发展自己的ETF市场大有裨益。     

平行分度凸轮机构的三维造型设计及其动态模拟

本文运用计算机辅助工业设计阐述了平行分度凸轮机的机构参数的选择、廓线的计算、三维造型设计及其动态模拟等ＣＡＤ的理论和方法。     

渐开线螺旋廓面包络蜗杆分度凸轮机构的理论分析

在包络蜗杆分度凸轮机构的基础上,提出了渐开线螺旋面包络蜗杆分度凸轮机构啮合原理分析,包括共轭廓面方程的建立、界限条件的确定、共轭诱导曲率的分析。为原型机的设计和制造奠定了基础。     

独具特色的解形识字教学法

文章介绍了全新的“一步检字法” ,这种检字法简单便捷是中文检索的一项创新。解形识字法的推广对改革中小学汉字教学 ,提高课堂教学效率 ,促进国际汉字教学都具有重大意义。     

采用动态主分量距离测度的视频索引技术

针对有界坐标技术(BCS)技术中静态计算主分量距离的固有缺陷,指出在高维空间中正轴顶点之间的距离不一定是主分量之间的最小距离,提出了一种基于动态主分量测度的视频索引方法,用于视频特征的相似性度量．该方法充分考虑了高维空间中主分量的方向特性,能够精确计算出主分量之间的最小距离,从而提高了视频特征相似性度量的准确性．在 30000个视频片段数据库上的实验表明,新方法能够显著提高BCS技术的查询准确率．     

基于Pro/toolkit的三片式平行分度凸轮CAD系统研究

采用面向对象的可视化开发工具Visual C＋＋6.0和Pro/toolkit开发了三片式平行分度凸轮的专用CAD系统。其主要思想是将全部的设计过程封装到系统内部,用户只需在界面上输入平行分度凸轮机构的必要几何参数和运动参数,即可得到所需尺寸的平行分度凸轮及其它零件的图形。该系统实现了三片式平行分度凸轮快速、准确的动态设计,可缩短产品设计开发周期,降低生产试制成本。     

模糊粗糙集在音频检索中的应用

音频具有数据量大、维数高等特点,直接进行音频检索会造成“特征维数灾难”,因此有必要从音频提取最能表现音频特征的音频帧。提出一种基于模糊粗糙集模型（Fuzzy Rough Set Model,FRSM）的音频数据约简算法,根据隶属度对音频数据进行模糊离散,基于知识表达能力约简属性,以等价划分计算具有等同分类能力的知识核。实验结果表明,该算法能够得到最小约简,并且最大程度地保持音频特征,提高检索效率。     

Optimizing the parallel adaptive indexing algorithm on multi-core CPUs

An improved parallel adaptive indexing algorithm on multi-core CPUs is proposed to solve the problems that the parallel adaptive indexing algorithms cannot take full advantage of the CMP's parallel execution resource, and properly process the sequential query pattern. Based on the optimization of the Refined Partition Merge algorithm, our improved parallel adaptive indexing algorithm combines the Parallel Database Cracking method with the Refined Partition Merge algorithm. In our algorithm, when fewer data chunks are in the index, we use the optimized Refined Partition Merge algorithm so as to reduce the probability of conflict between threads, decrease the waiting time, and increase the utilization of the threads, and when more data chunks are in the index, we use the Parallel Database Cracking method so as to take full advantage of the CMP's parallel execution resources. Besides, we propose an optimization for the robustness, which makes our algorithm suitable for two common query patterns. Experiments show that our method can reduce the query time by 25.7％～33.2％, and suit with common query patterns.     

Data-oriented multi-index Hashing

The multi-index hashing (MIH) is the state-of-the-art method for indexing binary codes. However, it is based on the dataset codes uniform distribution assumption, and will lower efficiency in dealing with non-uniformly distributed codes. In this paper, we propose a data-oriented multi-index hashing method. We first compute the correlations between bits and learn adaptive projection vector for each binary substring. Then, instead of using substrings as direct indices into hash tables, we project them with corresponding projection vectors to generate new indices. With adaptive projection, the indices in each hash table are nearly uniformly distributed. Besides, we put forward an entropy based measurement to evaluate the distribution of data items in each hash table. Experiments conducted on reference large scale datasets show that compared to the MIH the time performance of our method can be 36.9％～87.4％ better .     

配电系统节点优化编号方案比较

系统地分析和比较了现有的各种配电系统节点编号方案，建立了统一的分类标准，并对一些满足特定要求的编号方案进行了更具一般性的概括和描述，体现了节点编号方案的多样性和统一性。指出配电网辐射型结构的特点，使得节点编号方案在配电系统分析中具有重要意义，好的编号方案可以起到简化系统潮流方程和提高计算速度的作用。并指明了不同的潮流分析方法所适宜采用的节点编号方案。