Multi-dimensional scattering properties diagnosis system of scale aircraft model in an anechoic chamber

Aiming at the concept of ＂diagnosis＂, a simple and effective broadband radar cross section （RCS） measurement system is constructed, and some multi-dimensional scattering properties diagnosis techniques are presented based on the system. Firstly, a stepped-frequency signal is employed to achieve high range resolution, combining with a variety of signal processing tech- niques. Secondly, cross-range resolution is gained with a rotating table, and the high-resolution two-dimensional （2-D） imaging of the scale model is obtained by the microwave imaging theory. Finally, two receiving antennas with a small distance in altitude are used, and the three-dimensional （3-D） height distribution of scattering points on the scale model is extracted from the phase of images. Some typical bodies and a scale aircraft model are diagnosed in an anechoic chamber. The experimental results show that, after scaling with a metal sphere, the accurate one- dimensional （l-D） RCS pattern of the model is obtained, and it has a large dynamic range. When the bandwidth of the transmitting signal is 4 GHz, the resolution of the 2-D image can reach to 0.037 5 m. The 3-D height distribution of scattering points is given by interferometric measurement. This paper provides a feasible way to obtain high-precision scattering properties parameters of the scale aircraft model in a conventional rectangular anechoic chamber.     

从一题多解看中值定理的应用

该文研究了高等数学中中值定理在解题中的应用,分别通过计算题和证明题的实例阐明了四个中值定理的有机联系及应用要点,以帮助学生更深刻地理解和掌握中值定理这一教学的重点和难点。     

人影弹药安全存储报警装置研制

为解决基层人影作业点弹药安全存储问题,笔者开发研制了人影弹药安全存储报警装置,系统以三星ARM9 32位嵌入式RISC CPU S3C2410A处理器为硬件核心,根据报警装置需要实现的功能,添加适当的外围电路,主程序以嵌入式LINUX2.6.28作为操作系统而开发的具有远程报警、数据、监控画面上传等功能的报警系统。     

Upper bounds of differential characteristic probability for unbalanced Feistel network employing DSM

In this paper, for the unbalanced Feistel network which employs diffusion matrices in a switching way, we study the fixed number of its differential active S-boxes. Firstly we obtain some lower bounds of the differential active S-boxes for m, 2m and 3m rounds of Feistel structure, respectively. By concatenating these rounds, a fixed number of differential active S-boxes for arbitrary round number is derived. Our results imply that the unbalanced Feistel network using DSM is more secure than the traditional structure.     

粒度组成对KR搅拌头用浇注料性能的影响

以Andreassen颗粒紧密堆积理论为基础,研究KR搅拌头外衬莫来石浇注料临界粒度和粒度组成对其密度、强度和热震稳定性的影响.结果表明,随着临界粒度的增大,浇注料干燥和烧结后冷态密度与强度均明显提高;临界粒度一定时,粒度组成对浇注料冷态密度、强度以及热震稳定性的影响基本一致,但临界粒度不同的浇注料试样达到最佳性能所对应的粒度组成并不完全相同;与冷态性能相比,浇注料热震稳定性受临界粒度的影响较小.     

An Efficient Multidimensional Fusion Algorithm for IoT Data Based on Partitioning

The Internet of Things (IoT) implies a worldwide network of interconnected objects uniquely addressable, via standard communication protocols. The prevalence of IoT is bound to generate large amounts of multisource, heterogeneous, dynamic, and sparse data. However, IoT offers inconsequential practical benefits without the ability to integrate, fuse, and glean useful information from such massive amounts of data. Accordingly, preparing us for the imminent invasion of things, a tool called data fusion can be used to manipulate and manage such data in order to improve process efficiency and provide advanced intelligence. In order to determine an acceptable quality of intelligence, diverse and voluminous data have to be combined and fused. Therefore, it is imperative to improve the computational efficiency for fusing and mining multidimensional data. In this paper, we propose an efficient multidimensional fusion algorithm for IoT data based on partitioning. The basic concept involves the partitioning of dimensions (attributes), i.e., a big data set with higher dimensions can be transformed into certain number of relatively smaller data subsets that can be easily processed. Then, based on the partitioning of dimensions, the discernible matrixes of all data subsets in rough set theory are computed to obtain their core attribute sets. Furthermore, a global core attribute set can be determined. Finally, the attribute reduction and rule extraction methods are used to obtain the fusion results. By means of proving a few theorems and simulation, the correctness and effectiveness of this algorithm is illustrated.     

基于神经网络技术自动筛选Monastrol抑制剂的算法研究

带自动荧光显微镜的HCS（high content screening）系统是一种新兴的显微摄影、筛选和处理系统.HCS系统在摄影过程中会产生大量数据,人工筛选和识别费时费力.本文为了进行Monastrol抑制剂的筛选,基于前馈式神经网络技术研究了一种对HCS系统摄影的大量细胞同时进行特征提取和细胞显型识别的自动算法.在得到各个通道分离的图像后,对不同通道图像进行并行预处理,并采用神经网络和逻辑运算相结合的算法进行处理.我们将该方法运用于Monastrol抑制剂的筛选中,并将结果与人工识别结果进行分析比较.相比较前人提出的multi-phenotypic mitotic analysis（MMA）算法自动识别的正确率得以提高,可更好评估抗癌药剂效用.     

基于小波分析的WiMax网络业务流长相关性

为了精确有效地检测WiMax网络业务流的长相关性,利用自相似随机过程和小波变换都具有尺度不变性的特性,建立了表征长相关性的Hurst参数和小波系数的统计量.研究了业务流长相关性的小波估计法,反复选择小波消失矩和优化尺度参数的范围,减小这些因素对检测结果的影响.利用ON/OFF模型仿真WiMax网络中5种不同类型业务流,然后使用小波估计法对trace文件进行分析.检测分析结果表明:实时业务流的长相关性比较小,非实时业务流的长相关性相对较大;随着网络负载的增大,业务流的长相关性会略有变化,聚合业务流的长相关性的检测值与理论值基本吻合.     

A second generation human haplotype map of over 3.1 million SNPs

We describe the Phase II HapMap, which characterizes over 3.1 million human single nucleotide polymorphisms (SNPs) genotyped in 270 individuals from four geographically diverse populations and includes 25-35% of common SNP variation in the populations surveyed. The map is estimated to capture untyped common variation with an average maximum r2 of between 0.9 and 0.96 depending on population. We demonstrate that the current generation of commercial genome-wide genotyping products captures common Phase II SNPs with an average maximum r2 of up to 0.8 in African and up to 0.95 in non-African populations, and that potential gains in power in association studies can be obtained through imputation. These data also reveal novel aspects of the structure of linkage disequilibrium. We show that 10-30% of pairs of individuals within a population share at least one region of extended genetic identity arising from recent ancestry and that up to 1% of all common variants are untaggable, primarily because they lie within recombination hotspots. We show that recombination rates vary systematically around genes and between genes of different function. Finally, we demonstrate increased differentiation at non-synonymous, compared to synonymous, SNPs, resulting from systematic differences in the strength or efficacy of natural selection between populations.