Hash算法在数据库安全中的应用

介绍了Hash算法在数据库加密系统中的应用,包括在用户身份验证中的应用,在数据库完整性认证中的应用,以及在密文检索中的应用。     

本期用户索引

该书的内容主要包括：建筑智能化信息化技术的基础知识;建筑智能化技术中的楼字自控系统;空调系统自动化控制;楼宇自控系统中的智能控制及仿真;智能建筑中的安防系统;现代建筑中的火灾自动报警和消防联动控制系统;现代建筑中的综合布线和建筑智能化信息化的关系;现代建筑信息化技术中的通信与计算机网络系统;     

5G通信技术在城市轨道交通中的应用研究

基于5G通信技术在城市轨道交通中的应用研究,阐述5G通信技术的基本内容,分析城市轨道交通中的通信,探索5G通信技术在城市轨道交通中的具体应用,包括高速通信中的应用、端到端通信中的应用、大规模天线列阵中的应用以及绿色通信中的应用。5G通信技术对城市轨道交通发展具有重要作用,需要深入挖掘和利用5G通信技术的优势。     

计算机技术在高校体育教学中的应用研究

伴随着世界经济的发展,计算机已经发展到了各个领域,已经成为每个人生活中不可或缺的设备。本文就计算机技术在高校体育教学中的应用这一课题,从计算机技术在高校体育教学中的可行性、计算机技术在高校中的作用和计算机技术在高校体育教学中的应用措施三方面进行探究,力图找出计算机技术在高校体育教学中的应用漏洞,更好地的发挥计算机技术在高校体育教学中的应用。     

无线通信网络中的协作分集问题探析

无线网络中的协作通信是本文研究的对象。其中无线传感器网络中的节点能量优化分配和无线网络中的节点合作问题是本文的研究重点,在考虑了在传感器网络中的多路传输情况的基础上,提出一个无线传感器网络模型。     

谁来管键盘上的病毒

遭遇病毒,对于每一位电脑使用者而言,都意味着是一场灾难。随着病毒造成的危害越来越大,人们信息安全意识逐渐开始觉醒,从清除硬盘中的病毒、软盘中的病毒,到清除邮件中的病毒,再到清除引导区中的病毒、内存中的病毒,电脑似乎已经不存在病毒的立锥之地了。     

用CODAS—Ⅱ软件仿真单入－单出系统

本文简介九十年代国外自控领域中的最新仿真技术ＣＯＤＡＳ中的一个子集ＣＯＤＡＳ—Ⅱ以及其在经典控制理论的教学与设计中的应用，并以单入—单出线性连续系统中的仿真情况作举例说明。     

万能数据库查询分析器中的事务管理在Oracle中的应用

在事务控制是数据库应用系统中的关键技术之一,一开始先对事务控制的概念以及万能数据库查询分析器中的事务控制做了简介,之后以一个具体的实例给出万能数据库查询分析器中的事务控制在Oracle中的使用方法。由于《万能数据库查询分析器》是一种跨数据库平台的产品,所以对于在其它关系数据库系统中的事务管理,类同于本文中的实例。     

新商务显示

这是一个流光溢彩的显示年代。从生活中的电视机、工作中的显示器、商务和会议中的投影机、到公共场所中的LED显示屏,我们被各种各样的显示设备包裹着,主动或被动地接受着方方面面的内容和信息。     

浅析软件开发中的数据库设计的理论和实践

本文对软件开发中的数据库设计理论与实践进行了简单分析。首先,简单介绍了软件开发中的数据库设计的重要性;其次,分析了软件开发中的数据库设计的理论;最后,结合实例,分析了软件开发中的数据库设计的实践。     

A method of defuzzification based on the approach of areas' ratio

The new method of defuzzification of output parameters from the base of fuzzy rules for a Mamdani fuzzy controller is given in the paper. The peculiarity of the method is the usage of the universal equation for the area computation of the geometric shapes. During the realization of fuzzy inference linguistic terms, the structure changes from the triangular into a trapezoidal shape. That is why the universal equation is used. The method is limited and can be used only for the triangular and trapezoidal membership functions. Gaussian functions can also be used while modifying the proposed method. Traditional defuzzification models such as Middle of Maxima − MoM, First of Maxima − FoM, Last of Maxima − LoM, First of Suppport − FoS, Last of Support − LoS, Middle of Support − MoS, Center of Sums − CoS, Model of Height − MoH have a number of systematic errors: curse of dimensionality, partition of unity condition and absence of additivity. The above-mentioned methods can be seen as Center of Gravity − CoG, which has the same errors. These errors lead to the fact that accuracy of fuzzy systems decreases, because during the training root mean square error increases. One of the reasons that provokes the errors is that some of the activated fuzzy rules are excluded from the fuzzy inference. It is also possible to increase the accuracy of the fuzzy system through properties of continuity. The proposed method guarantees fulfilling of the property of continuity, as the intersection point of the adjustment linguistic terms equals 0.5 when a parametrized membership function is used. The causes of errors and a way to delete them are reviewed in the paper. The proposed method excludes errors which are inherent to the traditional and non- traditional models of defuzzification. Comparative analysis of the proposed method of defuzzification with traditional and non-traditional models shows its effectiveness.     

Ethical and legal issues for writing researchers in an age of media convergence

With the convergence of digital media into ever-widening social and technological networks for creation and distribution, the contexts for writing and the study of writing and writers have certainly changed. Researchers must navigate a dense matrix of ethical and legal issues in all phases of research when studying the ever-changing processes and products of digital communications. In this article, I draw from numerous sources to articulate a few of the challenges facing digital writing researchers in this age of convergence, focusing on issues of representation (researcher, participant, third-party), issues of informed consent, and issues of copyright and fair use.     

New debates on learning support

Abstract In the present debate on knowledge management and multimedia support of human learning, the word 'mediation' (of conduct) is often used as a natural correlate and rough equivalent to the word 'mediatisation' (of information). It is suggested that the distinction between the two words points to a basic difference between two types of processes which are crucial to a much needed rethinking of the conception and design of humanmachine interaction (HCI).
A redefinition of the 'appropriateness' of media support as the quality of the help to people's self-help rather than of direct control of their behaviour is proposed. Such a redefinition implies a radical shift of paradigm allowing for approaches to human learning as a cognitive activity in its own right. Another view of technological mediation is advocated, in keeping with some recent developments in HCI.     

HUYGENS' PRINCIPLE,PHYSICS AND COMPUTERS

We discuss the emergence of topology from a consideration of set extensions in General Systems Theory. Boundaries arise in a natural way, separating independent elements or regions of the system. Our aim is a unification of Etter theory, Kron's method of Tearing and Jessel's formulation of Huygens' Principle. This should make explicit the equivalence between the objective, structural, holographic and the subjective, relative definitions of information, sought in Bowden (1994b), reprinted in this Special Issue. It connects the abstract generalisations of Schrodinger's equation and Bom's rule derived in probabilistic Etter theory with the real world of electrical and other physical phenomena in General Physical Systems Theory. This paper can be considered as a continuation of Bowden (1990; 1994a) and as a response to Bowden (1994b), reprinted in this issue.

We review the ideas behind Kron's Method of Tearing and Jessel's Principle of Secondary sources (both special cases of the above theory) and their equivalence. We follow Hiley's argument in Hiley (1996) to show how Schrodinger's equation can be thought of as specifying the evolution of (a series of) tearings in continuous space. These can be shown on a commutative diagram as a series of similarity transforms. We compare this with Etter's derivation (Etter, 1998). We describe briefly a recently published derivation of Maxwell's equations from a non-commutative algebra and show how they fit onto a related commutative diagram. Finally we make some comments on applications of the general theory to computer systems. This paper is a series of vignettes of work in progress. It is designed to point the direction of work to come in Constructive Physics.     

An approach to the synthesis of fuzzy stabilization systems with a priori unknown model of an object

A method of synthesis of fuzzy stabilization systems for a broad class of dynamic objects under the assumption that the mathematical model of the object is not known a priori is proposed. The control is formulated in the form of a proportional law of adjustment as a function of a macro-variable; the square of the Euclidean norm of the phase variables is adopted as the macro-variable. An analogous variable characterizes the distance of the object from the equilibrium position. Despite the simplicity of the control law, its sign remains constant due to the fact that the macro-variable is positive-definite over the entire phase space. The switching times of the signals are determined by fuzzy identification of the system’s dynamic modes on the basis of measurement of the derivatives of the macro-variable.     

Forage quality of savannas — Simultaneously mapping foliar protein and polyphenols for trees and grass using hyperspectral imagery

Savanna covers about two-thirds of Africa, with forage quantity and quality being important factors determining the distribution and density of wildlife and domestic stock. Testing hypotheses about the distribution of herbivores is hampered by the absence of reliable methods for measuring the variability of vegetation quality (e.g. biochemical composition) across the landscape. It is demonstrated that hyperspectral remote sensing fills this gap by revealing simultaneously the spatial variation of foliar nitrogen (crude protein) as well as the total amount of polyphenols, in grasses and trees. For the first time, the pattern of resources important for feeding preferences in herbivores (polyphenols and nitrogen) is mapped across an extensive landscape and the modeled foliar concentrations are shown to fit with ecological knowledge of the area. We explain how estimates of nitrogen (crude protein) and polyphenols may be scaled up from point-based observations to reveal their spatial pattern, and how the variation in forage quality can influence the management of savannas, including farms, communal grazing areas, and conservation areas. It provides a glimpse of the choices herbivores must face in selecting food resources of different qualities.     

Innovative uses of ICT in Chilean schools

Abstract This paper presents some of the results of the study of seven cases of innovative pedagogical practices using ICT. The study was performed in the framework of the application of SITES M2 in Chile. The results are divided in two sections. First is a summary of each case, highlighting its innovative characteristics that serve as models of 'good practice' for Chilean teachers. Second, the results of the analysis of what teachers did are outlined; the impact on students and the type of teaching and learning activities in use. Results show that these projects did not provide evidence of having impact on students' learning as defined in the national curriculum. However, they show that students participating in these projects could learn other things, had the opportunity to develop abilities defined as cross-curricular and practised ICT related skills. The analysis of the teaching and learning activities highlights some deficiencies in the way that teachers implement new teaching strategies.     

动态规划求解中国象棋状态总数

中国象棋空间复杂度是分析中国象棋博弈难度的重要指标，中国象棋空间复杂度分析是一个计数问题，即求解中国象棋状态总数。根据中国象棋棋子的着法特征，该问题可分解为若干子问题，利用动态规划分别解决这些子问题，能够求出中国象棋状态总数的精确解。实验得出中国象棋状态总数约为7.54×10^39.88，过去许多文献描述的中国象棋状态总数是不准确的，远远高估了中国象棋状态总数。基于动态规划的计数方法也可以用于计算其他棋类的空间复杂度，也能够用于寻找空间复杂度较低的残局棋型，为构建中国象棋残局库提供依据。     

群智能新研究:角色?匹配的狼群劳动分工

启发于生物狼群群体的劳动分工行为,本文提出一种新颖的角色?匹配狼群劳动分工方法。通过剖析自然狼群的生物学行为,概括提炼出狼群劳动分工行为的个体任务的专职化、个体角色可塑性和任务分配均衡性3个典型特征,并建立了生物狼群劳动分工行为与普适性任务分配问题之间的仿生映射关系;从狼群“个体?个体”+“个体?环境”的交互方式角度出发,分析了角色?匹配的狼群劳动分工的个体角色转换和任务调整机制,研究了狼群角色?匹配的柔性劳动分工机制,提出了一种新的群智能方法,即角色?匹配的狼群劳动分工方法;将狼群的角色?匹配劳动分工与蚁群的刺激?响应劳动分工和蜂群的激发?抑制劳动分工进行了比较分析,并展示出角色?匹配狼群劳动分工方法的应用前景。