内存存储模型上的多表连接优化技术研究

分析了面向先进硬件平台上的数据库优化技术,提出了基于内存存储模型的多表连接查询处理优化技术,采用内存存储模型存储维表并对维表主键进行顺序化,从而使维表的主键与内存维表记录的内存偏移地址相一致,实现对维表记录的内存直接访问。通过列存储技术减少维表记录的访问宽度,进一步优化维表访问的cache性能。与基于SQL Server 2005的查询执行计划的连接算法、join index连接算法以及基于列存储模型的优化连接算法进行了实验比较和性能分析,结果表明:基于内存存储模型的多表连接算法在处理星型结构数据仓库多谓词、多连接的复杂查询时具有很好的性能,与join index相比不需要额外的空间开销,与列存储数据模型相比具有更好的兼容性和性能。     

利用路由器ACL功能保障局域网安全

路由器访问表是网络防御外来安全威胁的第一关,它是通过允许或拒绝信息流通过路由器的接口来实现的一种机制。该文介绍了访问表的基本概念、基本分类等,并以单位的华为路由器MSR30-16几个实际应用访问表的实例介绍了如何利用访问表来提高网络安全。     

网络安全：Cisco路由器的访问表

访问表是Cisco路由器的重要安全技术,用好这一技术,能在不增加投资的情况极大地提高网络的安全性。     

基于上下文的访问控制技术应用研究

利用Cisco路由器的访问表来实现分组过滤，作为防止网络攻击的第一道防线，它是通过允许或拒绝信息流流经路由器的接口来实现的一种安全管理机制。CBAC并非只是访问表的一种增强功能，而是一个相对复杂的安全工具集。本文分析了CBAC的工作方式和实现方法，并给出了一个CBAC应用的实例。     

SQL Server6.5的表扫描和索引访问性能比较

在SQL Server6.5中,表扫描和索引访问是两种主要的数据检索方法,是否使用簇索引或非簇索引是检索性能重要的因素,检索结果返回行数占表总行数的百分比（简称为返回百分比）对检索性也有很大的影响。索引访问的性能并非总是优于表扫描,事实上,选择检索方法的工作由查询优化器完成,但查询优化器并总能选择最快的方法。     

Visual Studio2010中访问VFP表方法研究

针对在Visual Studio 2010中的VB.NET下如何访问VFP表的方法进行了研究和讨论。常用的访问数据库表的方式有ADO、RDO和Ole Db等。主要讨论了ADO和RDO两种访问VFP表的方式。研究发现ADO方式访问VFP表存在一些BUG,会使程序出现异常。使用RDO方式访问VFP表,在软件发布时,需要将VFP的ODBC驱动程序vfpodbc.dll、组件文件Interop.RDO.dll和文件MSRDO20.dll进行打包,并对MSRDO20.dll进行注册。本文中给出了MSRDO20.dll的注册项和注册值,以及在应用Setup Factory 9建立的软件安装包中所要输入的注册代码。     

Jsp代码解析生成器的设计与实现

本文主要论述的是Jsp代码解析生成器的具体设计思路和实现过程，基于超大规模代码开发工作量的特征分析，根据需求访问系统表，获得相应所请求的参数，通过系统库表的规则动态构造SQL语言和动态构造界面，设计和实现代码生成器来充分利用有限的原有资源(人员调配、开发成本、时间分配)，加快开发进度、从而达到降低开发成本，缩短开发周期的目的。     

GPU无锁跳步哈希表

由于GPU具有卓越的并行加速能力,将通用的内存索引结构应用于GPU成了一个新的研究方向。目前,针对GPU进行优化的支持并发访问且可动态更新的内存索引结构还比较少。提出一种支持并发访问且可动态更新的GPU无锁跳步哈希表(GPU lock-free hopscotch Hash table,GLHT),采用全局内存配合原子操作以及特定的并发控制策略,在实现并发访问和无锁特性的同时,保证了读操作的无等待特性。GLHT结合高效的GPU内存合并访问和warp协同工作共享策略,获得了很高的并行加速能力。与现有CPU跳步哈希表相比,具有4～9倍的性能优势;比采取预先分配内存的GPU无锁链式哈希表更加灵活,并且在写操作较重的工作负载中获得了更好的性能。     

基于用户浏览时间的模式聚类算法

该文研究了基于用户访问时间的模式挖掘算法。对于具有公共访问子模式的用户,利用它们浏览页面的时间,设计和实现了一个简单而有效的聚类分析方法。     

XML数据模式下基于purpose的隐私访问控制策略研究与实现

提出构建基于purpose的对XML数据模式的隐私访问控制策略模型,解决由路径传递引起的查询隐私数据泄漏问题。基于purpose的隐私访问控制策略是一棵最小安全访问树模型。最小安全访问树是一组无冗余路径的以XPath{/,//,[]}片段表示的路径表达式,XPath{/,//,[]}是一组允许访问的隐私结点路径。实验表明最小安全树生成时间取决于隐私结点在一个XML文档中的标注时间和冗余路径的判别时间,而隐私结点的标注时间与隐私数据在XML文档中的分布位置有关。最小安全访问树模型能控制隐私数据的查询泄漏。     

基于RFID的磁盘加密系统

文章在跟踪和分析最新磁盘加密技术研究成果的基础上,设计了一种基于RFID的磁盘分区加密系统。该系统由磁盘分区加密软件Partition Crypt与RFID射频卡、USB射频读写端等硬件模块共同组成。软件部分对计算机硬件系统要求低、安装方便、使用简单、加密效果好;硬件部分由单片机与射频模块完成。其中,USB接口采用虚拟USB接口的方法,降低硬件复杂性与成本,具有很高的性价比。经过测试,整个系统功能稳定、性价比高、保密性好,可为广泛使用的基于Windows操作系统的涉密计算机提供加密技术保障,应用前景广阔。     

Vague集向Fuzzy集转化的一种新方法

提出Vague值向Fuzzy值转化的实用方法的定义。针对文献[6]中的一个Vague值向Fuzzy值转化的均值修正法,提出了加权均值修正法,并证明了这种方法同样是Vague值向Fuzzy转化的一种非常实用的方法。     

A formal approach to negotiating agents development

This paper presents a formal and executable approach to capture the behaviour of parties involved in a negotiation. A party is modeled as a negotiating agent composed of a communication module, a control module, a reasoning module, and a knowledge base. The control module is expressed as a statechart, and the reasoning module as a defeasible logic program. A strategy specification therefore consists of a statechart, a set of defeasible rules, and a set of initial facts. Such a specification can be dynamically plugged into an agent shell incorporating a statechart interpreter and a defeasible logic inference engine, in order to yield an agent capable of participating in a given type of negotiations. The choice of statecharts and defeasible logic with respect to other formalisms is justified against a set of desirable criteria, and their suitability is illustrated through concrete examples of bidding and multi-lateral bargaining scenarios.     

Developing a vision-based auto-recharging system for mobile robots

This article describes a vision-based auto-recharging system that guides a mobile robot moving toward a docking station. The system contains a docking station and a mobile robot. The docking station contains a docking structure, a control device, a charger, a safety detection device, and a wireless RF interface. The mobile robot contains a power detection module (voltage and current), an auto-switch, a wireless RF interface, a controller, and a camera. The controller of the power detection module is a Holtek chip. The docking structure is designed with one active degree of freedom and two passive degrees of freedom. For image processing, the mobile robot uses a webcam to capture a real-time image. The image signal is transmitted to the controller of the mobile robot via a USB interface. We use an Otsu algorithm to calculate the distance and orientation of the docking station from the mobile robot. In the experiment, the proposed algorithm guided the mobile robot to the docking station.     

Automatic Generation of Virtual Woodblocks and Multicolor Woodblock Printing

In this paper, we study a method to synthesize a multicolor virtual woodblock print by using several virtual woodblocks. It consists of two sections: carving and printing, to synthesize a virtual print. In the carving section, virtual woodblocks are generated by a user with supporting of an automatically carving method based on feature extraction of a gray value image. And woodblocks are also generated automatically by using a full-color image as a draft. In the printing section, a "paper sheet", a "printing brush" and "ink" are prepared in addition to the "woodblock" in the virtual space and the user synthesizes a woodblock print interactively. As the printing factors, a color of ink, a moisture value and a grain change the finish of the print. Using several virtual woodblocks and printing to a paper sheet in succession, a printing image of each woodblock is combined based on the printing factors and a multicolor virtual prints is synthesized.     

Detection of a brain aneurysm and a way to search for a brain aneurysm aimed at the development of a system to simulate an operation

In this article, a system is proposed for a simulated operation which would help a trainee surgeon to perform a medical operation to ensure that a cerebral aneurysm does not burst. The physician will have acquired empirical medical technologies from operations in traditional clinical teaching. However, there is a problem with safety and the burden to the patient. Therefore, recently a new training approach for a simulated medical operation using virtual reality has been explored. With the aim of developing a simulated system for a medical operation for a cerebral aneurysm, we considered the necessary functions such as detecting the brain aneurysm that is the target of the operation, and searching for a suitable blood vessel to make a plan for the operation.     

Bumpless transfer between observer-based gain scheduled controllers

This paper deals with bumpless transfer between a number of observer-based controllers in a gain scheduling architecture. Linear observer-based controllers are designed for a number of linear approximations of a non-linear system in a set of operating points, and gain scheduling control can subsequently be achieved by interpolating between each controller. The Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is used to achieve a smooth scheduling between the controllers. This approach produces a scheduled controller as a linear fractional transformation between a fixed controller and a scheduling parameter. The approach is tested on a simple, but highly non-linear model of a fossil fuel power plant.     

Panoramic appearance-based recognition of video contents using matching graphs

This paper proposes a general scheme for recognizing the contents of a video using a set of panoramas recorded in a database. In essence, a panorama inherently records the appearances of an omni-directional scene from its central point to arbitrary viewing directions and, thus, can serve as a compact representation of an environment. In particular, this paper emphasizes the use of a sequence of successive frames in a video taken with a video camera, instead of a single frame, for visual recognition. The associated recognition task is formulated as a shortest-path searching problem, and a dynamic-programming technique is used to solve it. Experimental results show that our method can effectively recognize a video.     

拟左群的一个代数结构

给出一个拟左群同构于拟群和左零带的直积的一个充分必要条件,同时给出了左群的收缩诣零扩张的一个刻画。     

An optimal part sending policy for a production system in a generalconfiguration with a new control strategy

We consider a production system in a general configuration with a new control strategy: the push mechanism for the part transport and the kanban technique for the work-in-process (WIP). The production system is composed of many stations such as an entrance station, a set of work stations, a central station, and an exit station, that are arranged in a general configuration. The push mechanism is followed for transporting a part from a station to a destination station. The kanban technique is adopted for controlling the WIP in a work station. The production system is modeled by a closed queuing network in a general configuration with a Markov part sending mechanism and a machine no blocking (MNB) technique. An optimal part sending policy that maximizes the expected system throughput is formulated into a long run average semi-Markov decision process. Three solution approaches are developed for obtaining optimal or suboptimal solutions. Numerical examples are given to evaluate the quality of the solutions obtained by the solution approaches