基于Windows NT局域网络全真模拟Internet操作测试功能的实现

文章介绍一种基于Ｗｉｎｄｏｗｓ ＮＴ局域网络,在Ｗｉｎｄｏｗｓ ９５／９８平台上使用的全真模拟Ｉｎｔｅｒｎｅｔ操作测试功能的实现方案,重点介绍了题库工作表结构,全真模拟Ｉｎｔｅｒｎｅｔ环境,操作考核主页设计及其相关技术要点。     

An encoding-based dual distance tree high-dimensional index

The paper proposes a novel symmetrical encoding-based index structure, which is called EDD-tree （for encoding-based dual distance tree）, to support fast k-nearest neighbor （k-NN） search in high-dimensional spaces. In the EDD-tree, all data points are first grouped into clusters by a k-means clustering algorithm. Then the uniform ID number of each data point is obtained by a dual-distance-driven encoding scheme, in which each cluster sphere is partitioned twice according to the dual distances of start- and centroid-distance. Finally, the uniform ID number and the centroid-distance of each data point are combined to get a uniform index key, the latter is then indexed through a partition-based B^＋-tree. Thus, given a query point, its k-NN search in high-dimensional spaces can be transformed into search in a single dimensional space with the aid of the EDD-tree index. Extensive performance studies are conducted to evaluate the effectiveness and efficiency of our proposed scheme, and the results demonstrate that this method outperforms the state-of-the-art high-dimensional search techniques such as the X-tree, VA-file, iDistance and NB-tree, especially when the query radius is not very large.     

Fabrication of Flexible Transducer Arrays With Through-Wafer Electrical Interconnects Based on Trench Refilling With PDMS

Flexible transducer arrays are desired to wrap around catheter tips for side-looking intravascular ultrasound imaging. We present a technique for constructing flexible capacitive micromachined ultrasonic transducer (CMUT) arrays by forming polymer-filled deep trenches in a silicon substrate. First, we etch deep trenches between the bottom electrodes of CMUT elements on a prime silicon wafer using deep reactive ion etching. Second, we fusion-bond a silicon-on-insulator (SOI) wafer to the prime silicon wafer. Once the silicon handle and buried oxide layers are removed from the back side of the SOI wafer, the remaining thin silicon device layer acts as a movable membrane and top electrode. Third, we fill the deep trenches with polydimethylsiloxane, and thin the wafer down from the back side. The 16 by 16 flexible 2-D arrays presented in this paper have a trench width that varies between 6 and 20 ; the trench depth is 150 ; the membrane thickness is 1.83 ; and the final substrate thickness is 150 . We demonstrate the flexibility of the substrate by wrapping it around a needle tip with a radius of 450 (less than catheter size of 3 French). Measurements in air validate the functionality of the arrays. The 250- by 250- transducer elements have a capacitance of 2.29 to 2.67 pF, and a resonant frequency of 5.0 to 4.3 MHz, for dc bias voltages ranging from 70 to 100 V.     

Harmonizing Hierarchical Manifolds for Multimedia Document Semantics Understanding and Cross-Media Retrieval

In this paper, we consider the problem of multimedia document (MMD) semantics understanding and content-based cross-media retrieval. An MMD is a set of media objects of different modalities but carrying the same semantics and the content-based cross-media retrieval is a new kind of retrieval method by which the query examples and search results can be of different modalities. Two levels of manifolds are learned to explore the relationships among all the data in the level of MMD and in the level of media object respectively. We first construct a Laplacian media object space for media object representation of each modality and an MMD semantic graph to learn the MMD semantic correlations. The characteristics of media objects propagate along the MMD semantic graph and an MMD semantic space is constructed to perform cross-media retrieval. Different methods are proposed to utilize relevance feedback and experiment shows that the proposed approaches are effective.     

一种用于机群系统的双环光互连网络性能分析

高性能计算机网络对带宽的需求,使得如何提供高带宽的互连网络以及充分利用互连网络的固有带宽度为一个研究焦点。基于Linux操作系统,以千兆光互连接口卡为网络接口,设计实现了一种可用于机群系统的双环光互连网络。介绍了光互连网接口卡的基本结构,接口卡驱动软件的设计方法,双环光互连网络的拓朴结构及其特性。分析测试了光互连网络的通信性能,指出了影响系统整体性能的关键因素。     

提取抽油井液位回音信号中液位值的方法

分析了抽油井液位回音曲线的特性,给出了检测曲线中特性脉冲的电路原理,介绍了根据统计规律计算声速和液位值的方法,该方法与计算机结合可以消除在测量中人为读数和干扰的影响,使得测量变得精确、方便、直接。此方法在实际中已得到了较好的应用。     

Windows NT的安全问题

本文从ＷｉｎｄｏｗｓＮＴ的交式登录过程、Ｗｉｎ３２ＷｉｎＬｏｇｏｎ进程进行用户信息登录、管理员利用域用户管理器用户建立帐号及设置安全属性、设置用户权限、目录访问权限类型、文件系统和打印机的安全性能、设置访问许可权、ＮＴＦＳ目录级别权限、对服务器系统进行物理性能方面的设置、审计、设置登录标语、注册表面的安全性,安全保障的几个方面、ＷｉｎｄｏｗｓＮＴ中的缺陷等诸多方面讨论了ＷｉｎｄｏｗｓＮＴ的安全问题     

模式识别方法及其在地球物理勘探中的应用

将模式识别方法应用于地球物理资料处理,近年来已引起了国内外学术界的注意。模式识别可以使我们充分利用在野外获得的资料,从中“榨取”出更多的地质信息。它不仅可能自动提取我们所需要的地球物理资料,而且还可能对所提取出来的资料自动进行“解释”。本文主要说明在用计算机进行地球物理资料的自动处理和解释时,可以把其中一些问题归结为模式识别问题,从而可以运用模式识别的许多原理和方法。文中简要介绍了统计模式识别和结构模式识别两大类方法的一般原理。较详细地介绍了用句法方法识别波形和标记的松驰算法,以及它们在地球物理资料自动处理中可能的应用。这是一个值得注意的、有价值的研究领域。     

多线程技术在嵌入式数据采集系统中的应用

讨论了多线程技术在嵌入式数据采集系统中的应用，给出了PC机与嵌入式计算机系统的多线程串行通信的实现。     

蚁群算法用于VLSI布线的特性分析

本文重点在于研究在VLSI布线中采用蚁群算法的实用性和优越性。通过用MATLAB编程对蚁群算法和迷宫算法等算法的实现,得出蚁群算法在VLSI布线中的适用性不受布线结构的限制,而且在得出最优解方面有一定的优势。