DDS PLL短波频率合成器设计

本文讨论了DDS PLL结构频率合成器硬件电路设计中需要考虑的几方面问题并给出了设计原则,依此原则我们设计了一套短波波段频率合成器,实验结果证实了其可行性。     

基于医疗文本数据聚类的帕金森病早期诊断预测

针对多发于老龄人群的帕金森病（PD）的早期智能化诊断的问题，提出基于医疗检测文本信息数据的聚类技术来对PD进行分析预测。首先，对原始数据集进行预处理以获取有效特征信息，并通过主成分分析（PCA）方法将原始特征分别降维到8个不同维度的维度空间；然后，应用5个传统的经典聚类模型和3种不同的聚类集成方法分别对8个维度空间的数据进行聚类；最后，采用4个聚类性能指标来预测数据集中的多巴胺异常PD患者、健康体和无多巴胺缺失（SWEDD） PD患者。仿真结果显示，PCA特征维度值取30时，高斯混合模型（GMM）的聚类准确度达到89.12%；PCA特征维度值取70时，谱聚类（SC）的聚类准确度达到61.41%；PCA特征维度值取80时，元聚类算法（MCLA）的聚类准确度达到59.62%。对比实验结果表明，5种经典聚类方法中，PCA的特征维度值小于40时，高斯混合模型聚类效果最佳；3种聚类集成方法中，对于不同的特征维度，MCLA的聚类性能均表现优异，进而为PD的早期智能化辅助诊断提供了技术和理论支撑。     

A faster parameterized algorithm for set packing

We present an efficient parameterized algorithm for the (k,t)-set packing problem, in which we are looking for a collection of k disjoint sets whose union consists of t elements. The complexity of the algorithm is O(²O(t)nNlogN). For the special case of sets of bounded size, this improves the O(k(ck)n) algorithm of Jia et al. [J. Algorithms 50 (1) (2004) 106].     

The Little Towers of Antwerpen problem

The Little Towers of Antwerpen problem is a simple variant of the Towers of Hanoi problem requiring the interchanging of two stacks (black, white) of N rings using the third tower as a spare, subject to the usual rules governing ring movement. An optimal algorithm for the problem is presented and its performance is analyzed.     

An algorithm for computing the restriction scaffold assignment problem in computational biology

Let S and T be two finite sets of points on the real line with |S|+|T|=n and |S|>|T|. The restriction scaffold assignment problem in computational biology assigns each point of S to a point of T such that the sum of all the assignment costs is minimized, with the constraint that every element of T must be assigned at least one element of S. The cost of assigning an element si of S to an element tj of T is |si−tj|, i.e., the distance between si and tj. In 2003 Ben-Dor, Karp, Schwikowski and Shamir [J. Comput. Biol. 10 (2) (2003) 385] published an O(nlogn) time algorithm for this problem. Here we provide a counterexample to their algorithm and present a new algorithm that runs in O(n²) time, improving the best previous complexity of O(n³).     

Tags for Multi-Protocol Authentication

Formal methods have been proved successful in analyzing different kinds of security protocols. They typically formalize and study the security guarantees provided by cryptographic protocols, when executed by a (possibly unbounded) number of different participants. A key problem in applying formal methods to cryptographic protocols, is the study of multi-protocol systems, where different protocols are concurrently executed. This scenario is particularly interesting in a global computing setting, where several different security services coexist and are possibly combined together. In this paper, we discuss how the tagging mechanism presented in [M. Bugliesi, R. Focardi, and M. Maffei. Compositional analysis of authentication protocols. In Proceedings of European Symposium on Programming (ESOP 2004), volume 2986 of Lecture Notes in Computer Science, pages 140–154. Springer-Verlag, 2004, M. Bugliesi, R.Focardi, and M.Maffei. A theory of types and effects for authentication. In ACM Proceedings of Formal Methods for Security Engineering: from Theory to Practice (FMSE 2004), pages 1–12. ACM Press, October 2004] addresses this issue.     

激光粒度分析结果在形貌分析中的应用

激光粒度分析仪通常只用于颗粒大小与分布的测定。通过比较粉体颗粒的激光粒度分析与扫描电镜分析的结果，发现，激光粒度分析仪所测定的粒度分布函数同时包含了一些形貌分析信息。利用这些信息可为试样进一步作SEM测定创造了条件。     

自适应跳频卫星通信系统的设计与实现

鉴于自适应跳频系统的良好抗干扰性能,提出了一种自适应跳频卫星通信系统的设计方案。在简要介绍自适应跳频技术基本原理的基础上,叙述了自适应跳频通信系统的结构和通信过程,重点讨论了自适应跳频卫星通信系统的设计模型、同步方式、频率集更新算法和抗干扰性能,最后,给出了自适应跳频卫星通信抗干扰终端设备的基本实现过程。     

基于Bark小波变换参数的语音寂声/语声段检测

提出了一种基于Bark小波变换参数的语音寂声/语声段检测方法。利用Bark小波的频率分级和能量聚焦能力,提取语音信号在不同子带上的统计参数;引入基于模糊熵的参数有效性分析,获得所有子带参数中分辨能力和稳定性最大的参数作为识别参数。仿真试验证明,该方法在不同噪声条件下稳定有效;比照传统参数,该方法在准确率和鲁棒性上都有较大幅度的提升。     

变频调技术在铁路范围内的应用

介绍了变频调速在铁路范围内的应用，重点叙述了变频技术在铁路锅炉房鼓引风、行车、恒压供水、空压机和冲洗泵方面应用。