BEB冲突分解算法时延性能计算机仿真及分析

利用MATLAB设计计算机程序对阻塞式信道条件下的随机多址接入系统MAC协议中二进制指数后退算法(BEB)进行仿真实验研究，得到了在多种初始条件下系统的冲突分解效率和终端接入时延性能的数值结果，对实验结果进行了总结分析，获得一些有意义的结论．     

汽车零部件制造技术的发展及应用

归纳了汽车零部件制造中的各种加工方法及工艺，对目前在现代汽车制造中所应用的最新的加工方法及工艺作出介绍和分析，为中国汽车零部件生产企业提供技术参考。     

2种NdFeB粉末的混炼研究

采用快淬法和雾化法制得的2种不同形貌的NdFeB磁粉,以尼龙12作粘结剂,研究了注射成形粘结磁体的混炼过程。分析了2种磁粉的形貌与粉末粒度及其分布,对混合料的粉末临界充填率、均匀度、流变特性的影响,以及混炼温度对磁性能的影响。     

C/C复合材料烧蚀性能的研究进展

C／C复合材料是一种良好的抗烧蚀和耐高温结构材料,广泛地应用于航天航空各领域。在此,作者综述了C／C复合材料烧蚀性能的测试方法、烧蚀机理、烧蚀模型以及抗烧蚀的研究状况。     

谈现代小说中人力车夫形象

通过《一件小事》、《薄奠》和《骆驼祥子》三部作品中的比较分析,从“人力车夫”这一都市劳动人民的主人公形象,我们可以看到其工人阶级的友爱精神和高尚品质,同时,要清醒认识到在旧制度下劳动者的悲剧命运是无法避免的。     

三维捷联磁传感器模拟器的研究与实现

三维捷联磁传感器模拟器是根据实际需要而研制开发的。通过对三维捷联磁传感器工作机理的剖析,完成了三维捷联磁传感器模拟器的软件算法,并实现了该模拟器的硬件系统,在实际应用中取得了很好的效果。传感器模拟器的研制和使用,开拓了传感器的研究范围,对于更好地研究和开发传感器具有重要的指导意义。     

Fabrication of NiO Buffer Layer for YBCO Coated Conductors by Combining Sputtering and SOE Method

In research of YBCO coated conductors, the development of a oxide template for epitaxial growth of YBCO is very important. Matsumoto et al have demonstrated the potential of the surface oxidation epitaxial (SOE) route for formation a cube textured NiO layer on nickel tapes. The epitaxial NiO functions as a buffer layer of chemical reaction between YBCO and nickel, and as a template for the epitaxial growth of YBCO. However, the surface quality of NiO is difficult to control and defects such as crack, spall and deep grooves exist in SOE NiO layer. A new approach combining sputtering and SOE method to obtain crack-free and cube textured NiO layer were reported. Ni tapes prepared by the combination of rolling and recrystallization were used for this work. A coating of Ni was first deposited on the tapes via magnetron sputtering. Then on the coating tapes, continuous and textured NiO layer were achieved by SOE technology.     

信道自适应主动块低频分量丢弃数字图像传输技术

为减少图像传输的数据量,满足信道带宽的要求,在图像发送端以块为单位对图像进行划分,利用离散余弦变换(DCT),按照一定的规则主动丢弃部分块的低频分量,而在图像接收端通过图像重建技术对丢弃的图像数据进行恢复,从而再现原图像。实验结果表明这种数字图像传输技术改善了DCT图像质量。     

电子政务CA证书申请体系

文章在介绍常规的证书申请实现方法的基础上，分析了电子政务中单位CA证书申请的特殊性，并且针对这些特殊性，设计了符合实际需要的体系结构和实现方法。     

Mining Frequent Patterns without Candidate Generation: A Frequent-Pattern Tree Approach

Mining frequent patterns in transaction databases, time-series databases, and many other kinds of databases has been studied popularly in data mining research. Most of the previous studies adopt an Apriori-like candidate set generation-and-test approach. However, candidate set generation is still costly, especially when there exist a large number of patterns and/or long patterns.In this study, we propose a novel frequent-pattern tree (FP-tree) structure, which is an extended prefix-tree structure for storing compressed, crucial information about frequent patterns, and develop an efficient FP-tree-based mining method, FP-growth, for mining the complete set of frequent patterns by pattern fragment growth. Efficiency of mining is achieved with three techniques: (1) a large database is compressed into a condensed, smaller data structure, FP-tree which avoids costly, repeated database scans, (2) our FP-tree-based mining adopts a pattern-fragment growth method to avoid the costly generation of a large number of candidate sets, and (3) a partitioning-based, divide-and-conquer method is used to decompose the mining task into a set of smaller tasks for mining confined patterns in conditional databases, which dramatically reduces the search space. Our performance study shows that the FP-growth method is efficient and scalable for mining both long and short frequent patterns, and is about an order of magnitude faster than the Apriori algorithm and also faster than some recently reported new frequent-pattern mining methods.