基于粗糙集数据挖掘算法的决策分析

介绍了粗糙集理论的基本概念和特点,研究了基于概念泛化和粗糙集的数据挖掘算法(CRCG)的决策分析,并以拉深模具为例,将其应用于模具质量评价和诊断,使模具质量控制的决策更科学、合理。     

引伸计误差对Rp0.2测量结果的影响

就引伸计标距误差和引伸计系统误差对RP0.2测量结果的影响进行了分析。对几种材料的试验误差分析表明,应变误差造成的RP0.2的测量误差依赖于材料自身的特性。对于普通材料,其应变误差对拉伸性能RP0.2造成的误差可以假设小于1%;但是对于某些合金材料,引伸计误差对拉伸性能RP0.2造成的误差大于1%,在测量这些材料时需要采用比规定级别更高的引伸计。     

精确的时间同步技术

在多基地雷达系统中,同步问题包括时间同步和频率同步,如何使得异地之间的时钟同步是我们必须研究的问题。所谓时间同步,是使2个时钟对准,或者是确切知道2个时钟的钟差,在后续处理中补偿这个钟差。时间同步有很多方法,其中时间双向比对法,由于对站点的精确性依赖性小,受外界环境影响小,通过短时间比对和处理就可以获得较高的时间同步精度,因此它已被ITU组织作为全球时间传递和比对的标准。     

一种基于块编码的压缩视频通信差控算法

提出了一种压缩视频传输的差错控制机制,联合编码端,信道和解码端对差错进行预防、控制、检测和修复,对压缩视频传输进行控制.并给出了算法的可行性分析.     

粗糙集分类中耦合数据的处理方法研究

对基于粗糙集挖掘中的耦合数据概念进行了研究,给出了两类耦合数据的定义,研究了耦合数据的检测问题和处理方法,并将对耦合数据的处理方法加入Rosetta算法中,对该算法进行了改进.实例研究表明,这种对耦合数据的处理方法是有效的.     

基于增量式更新带权差别集合的属性约简算法

在面向差别矩阵的约简算法思想的基础上,定义一种新的带权差别集合(WDS)模型,并提出了高效更新带权差别集合的算法,分析了该更新算法的时间和空间复杂度.随后,基于快速更新带权差别集合算法,提出一种增量式属性约简方法.当有新的数据对象被加入决策表,可有效提高属性约简的效率.理论分析和实验结果表明该算法适用于大数据集的约简.     

一种基于粗糙集的纳税人属性约简方法．

基于粗糙集理论,对基于属性重要度的启发式属性约简算法进行了改进,并将改进后算法运用于纳税人属性约简的实际工作中.该算法解决了原有基于属性重要度的启发式属性约简算法结果中存在冗余属性问题,实现了属性选择较小化,并保持原有数据分类能力不发生大的变化.通过属性约简实验结果和实际工作情况对比,证明该算法具有很好的性能.     

Basis Translation Matrix between Two Isomorphic Extension Fields via Optimal Normal Basis

This paper proposes a method for generating a basis translation matrix between isomorphic extension fields. To generate a basis translation matrix, we need the equality correspondence of a basis between the isomorphic extension fields. Consider an extension field F_p^m where p is characteristic. As a brute force method, when p^m is small, we can check the equality correspondence by using the minimal polynomial of a basis element; however, when p^m is large, it becomes too difficult. The proposed methods are based on the fact that Type I and Type II optimal normal bases (ONBs) can be easily identified in each isomorphic extension field. The proposed methods efficiently use Type I and Type II ONBs and can generate a pair of basis translation matrices within 15 ms on Pentium 4 (3.6 GHz) when mlog₂ p = 160.     

三峡右岸巨型全空冷水轮发电机组关键技术——水轮机篇

本文介绍了三峡右岸国内首台840MVA级水轮发电机组关键技术之一的模型转轮的水力特性研究情况.针对左岸引进模型转轮在高负荷区域存在压力脉动幅值大于5%的不稳定性问题,哈尔滨电机厂有限责任公司自主研发的右岸模型转轮具有较宽的稳定性运行范围,消除了高负荷区域压力脉动.最高效率达到94.7(3%,空化、飞逸、强度等性能均优于左岸模型.这也标志着我国自主设计、制造安装巨型水轮发电机组的时代已经到来.     

Cold Plasma‐Mediated Treatments for Shelf Life Extension of Fresh Produce: A Review of Recent Research Developments

Fresh produce, like fruits and vegetables, are important sources of nutrients and health‐promoting compounds. However, incidences of foodborne outbreaks associated with fresh produce often occur; it is thus important to develop and expand decay‐control technologies that can not only maintain the quality but can also control the biological hazards in postharvest, processing, and storage to extend their shelf life. It is under such a situation that plasma‐mediated treatments have been developed as a novel nonthermal processing tool, offering many advantages and attracting much interest from researchers and the food industry. This review summarizes recent developments of cold plasma technology and associated activated water for shelf life extension of fresh produce. An overview of plasma generation and its physical–chemical properties as well as methods for improving plasma efficiency are first presented. Details of using the technology as a nonthermal agent in inhibiting spoilage and pathogenic microorganisms, inactivating enzymes, and modifying the barrier properties or imparting specific functionalities of packaging materials to extend shelf life of food produce are then reviewed, and the effects of cold plasma‐mediated treatment on microstructure and quality attributes of fresh produce are discussed. Future prospects and research gaps of cold plasma are finally elucidated. The review shows that atmospheric plasma‐mediated treatments in various gas mixtures can significantly inhibit microorganisms, inactive enzyme, and modify packaging materials, leading to shelf life extension of fresh produce. The quality attributes of treated produce are not compromised but improved. Therefore, plasma‐mediated treatment has great potential and values for its application in the food industry.