B/S结构下的用户访问控制方法

针对Web系统的特点以及其对用户访问控制的特殊要求,提出了在B/S结构下基于"角色-模块-页面模型"实现用户访问控制的基本思想,并讨论了其具体的实现方法."角色-模块-页面模型"以传统的RBAC权限管理模型为基础,将模块看作是一系列页面的集合,并以二进制数值来描述角色对各模块的访问权限以及各页面的操作功能,从而将用户对模块页面的操作权限判断转化为一系列的逻辑运算.通过在高速公路机电设备养护系统中的实际应用,表明提出的用户访问控制方法能够很好地满足企业对Web系统用户访问控制的要求,通用性好,扩展性强,配置简单灵活.     

A data-centric design for n-tier architecture

The increasing heterogeneity, complexity, and distributed nature of deployment architectures only serve to compound the problems faced by software solutions. With the advent of the Internet and web technologies, system designers have had to reevaluate the applicability of n-tier architectures, and assess which technologies are appropriate at each tier. In this paper we evaluate the design issues of n-tier architecture. We debate whether it is good to move code or data to communicate messages between applications. Based on the latest technology of J2EE and .NET framework, we recommend a data centric design of n-tier architecture. Based on our experience we also suggest a modified interactive software process model.     

基于B/S软件体系结构的研究

在软件开发过程中,软件体系结构的设计起着非常重要的作用,用它来指导整个软件的开发,可以准确地满足用户的需要并降低软件的开发成本。将软件体系结构与分层思想相结合,给出了当前广泛应用的基于B／S的软件体系结构的框架和框架的具体实现,指出了设计及应用过程中应该注意的问题。     

一种新的ATM／IP地址解析体系结构—NRS／HRS

提出了一种新的ATM/IP地址解析体系结构-NRS/HRS,并描述了该体系结构的工作机制,通过理论分析和软件仿真,证明NRS/HRS的解析效率有较大幅度的提高。     

Visual architecture and cognitive architecture

Traditional architectures have fundamental epistemological problems. Perception is inherently resource limited so controlling perception involves all the same AI-complete problems of reasoning about time and resources as the full-scale planning problem. Allowing a planner to transparently assume that the information it needs will automatically be present and up-to-date in the model thus presupposes a solution to a problem at least as difficult as planning itself. Although one can imagine many possible solutions to this problem, such as allowing the planner to recurse on its own epistemological problems, there have been no convincing attempts at this. In this paper, I compare behaviour-based and traditional systems in terms of their representational power and the strengths of their implicit epistemological theories. I argue that both have serious limitations and that those limitations are not addressed simply by joining the two into a hybrid. I discuss my work with using vision to support real-time activity and give an example of an interesting intermediate point between reactive and classical architectures that preserves the simplicity and parallelism of behaviour-based systems while supporting ‘symbolic’ representations. Traditionally, AI theories have assumed, either implicitly or explicitly, an architecture in which modules of the mind (perception, reasoning, motor control, etc.) are linked by way of some centralized database like structure, often referred to as a world model. Recently, a number of alternative architectures have been proposed which, to greater or lesser degrees, claim to do away with world models or with representations entirely. Many of the criticisms of traditional architectures revolve around speed and timescale. Planning, so the story goes, is slow but flexible, while feedback loops are fast but stupid. A common approach, both in this special issue and in the literature in general, is to adopt a hybrid which fuses a slow planner running on a long time-scale and a set of fast feedback loops running on a short time-scale. The problem with this argument is that planning is not slow, it is combinatorially explosive. Running an O(2 ⁿ ) algorithm on a time-scale ten times slower is the same as running it on a computer ten times faster : it simply lets one increase n by three. If time-scale were the true problem, faster CPUs would make tiered architectures obsolete in a few years. I believe the true issues are not speed, in the sense of time-scale, but combinatorics and epistemology. The former has been extensively discussed, so I will focus on epistemology. Clearly, if an agent architecture is to be successful it must take into account the capacities and limitations of perception. In this paper I discuss the influence of perceptual architecture on agent architecture, argue that the recent wave of tiered architectures do not adequately address these problems, and discuss my work on using vision to support real-time activity.     

IBM RISC System/6000: architecture and performance

The IBM RISC System/6000, a superscalar microprocessor, is presented. The architecture of this processor has its instruction set specifically designed for a superscalar machine containing three independent units-branch, fixed-point, and floating-point. The design also emphasizes high-performance floating-point operations. The design principles are to offer maximum overlap of the three functional units, avoid dead cycles, and define instructions that can (for the most part) be completed at a rate of one per cycle. The branch cycle, fixed- and floating-point units, cache management, and performance are described. Benchmark results are given     

基于C/S架构的学生调查问卷系统的实现

为能更好地掌握学生的思想动态、心理状态、生活需要及行为习惯等,同时,学校都具有数量较多的机房使网上问卷调查具有可行性,因此开发了本小型学生调查问卷系统。该系统采用Visual Basic 6.0和SQL Server 2005实现,可以动态完成问卷的初始化,客户端试卷的生成和最终的问卷数据统计,为调查问卷的活动开展提供了便利。     

G/S模式面向服务架构研究

系统分析和总结了数字地球、空间信息服务模式、G/S模式的特点,设计了空间信息服务模式的理论模型,定义了G/S模式下面向服务的软件架构,设计了HGML文档共享子系统,并对G/S模式下面向服务的系统应用前景进行了展望。     

A secure architecture for TCP/UDP-based cloud communications

International Journal of Information Security - Cloud communication is an intrinsic aspect of cloud architecture. It is an internet-based communication that enables access to millions of cloud...     

An IMS-based integration architecture for WiMax/LTE handover

To enable seamless handovers for broadband networks, many researchers have addressed the integration of heterogeneous access technologies to provide users with always-on connectivity. Currently, there are several researches reported in the literature that discuss the integration of beyond 3G networks such as 3GPP Long Term Evolution LTE and mobile WiMax networks. They mainly focused on providing mobile users with seamless mobility when switching between heterogeneous access networks. In this context, many solutions for integration architecture have been proposed with mobility management considerations such as loose and tight coupling, IP Multimedia Subsystem IMS-based architecture and Evolved Packet Core EPC-based solutions for the purpose of providing mobile users with seamless handovers. In this paper, we present the different integration solutions and propose an integration architecture for WiMax and LTE access technologies with EPC as core network and IMS for service provisioning. A vertical handover VHO scheme is presented based on cross-layer approach that enables vertical handover with less handover latency and signaling cost.     

A power-aware code-compression design for RISC/VLIW architecture

We studied the architecture of embedded computing systems from the viewpoint of power consumption in memory systems and used a selective-code-compression (SCC) approach to realize our design.Based on the LZW (Lempel-Ziv-Welch) compression algorithm,we propose a novel cost effective compression and decompression method.The goal of our study was to develop a new SCC approach with an extended decision policy based on the prediction of power consumption.Our decompression method had to be easily implemented in hardware and to collaborate with the embedded processor.The hardware implementation of our decompression engine uses the TSMC 0.18μm-2p6m model and its cell-based libraries.To calculate power consumption more accurately,we used a static analysis method to estimate the power overhead of the decompression engine.We also used variable sized branch blocks and considered several features of very long instruction word (VLIW) processors for our compression,including the instruction level parallelism (ILP) technique and the scheduling of instructions.Our code-compression methods are not limited to VLIW machines,and can be applied to other kinds of reduced instruction set computer (RISC) architecture.     

一种基于AJAX技术的B/S与C/S混合构架模式

在分析当前客户机/服务器(C/S)与浏览器/服务器(B/S)混合架构模式与AJAX技术的基础上,提出了一种新的混合架构模式,这种架构模式基于Web服务技术和AJAX技术,统一了B/S与C/S的前台交互方式,融合了两种模式的优点,有效地实现了服务器端共享,增强了此类系统的可维护性与可扩展性。在此模式指导下,设计了动力学应用平台的架构,为类似此种架构的系统实现提供了一定参考。     

Algorithmic Graph Minor Theory: Improved Grid Minor Bounds and Wagner’s Contraction

We explore three important avenues of research in algorithmic graph-minor theory, which all stem from a key min-max relation between the treewidth of a graph and its largest grid minor. This min-max relation is a keystone of the Graph Minor Theory of Robertson and Seymour, which ultimately proves Wagner’s Conjecture about the structure of minor-closed graph properties. First, we obtain the only known polynomial min-max relation for graphs that do not exclude any fixed minor, namely, map graphs and power graphs. Second, we obtain explicit (and improved) bounds on the min-max relation for an important class of graphs excluding a minor, namely, K _3,k -minor-free graphs, using new techniques that do not rely on Graph Minor Theory. These two avenues lead to faster fixed-parameter algorithms for two families of graph problems, called minor-bidimensional and contraction-bidimensional parameters, which include feedback vertex set, vertex cover, minimum maximal matching, face cover, a series of vertex-removal parameters, dominating set, edge dominating set, R-dominating set, connected dominating set, connected edge dominating set, connected R-dominating set, and unweighted TSP tour. Third, we disprove a variation of Wagner’s Conjecture for the case of graph contractions in general graphs, and in a sense characterize which graphs satisfy the variation. This result demonstrates the limitations of a general theory of algorithms for the family of contraction-closed problems (which includes, for example, the celebrated dominating-set problem). If this conjecture had been true, we would have had an extremely powerful tool for proving the existence of efficient algorithms for any contraction-closed problem, like we do for minor-closed problems via Graph Minor Theory.     

MCA-CMA次分量分析恒模算法

提出了一种次分量分析恒模算法(Minor component analysis-constant modulus algorithm,MCA-CMA).该算法从恒模代价函数出发,推导出一个基于Rayleigh熵形式的代价函数,根据Rayleigh熵的性质,可得出最优权矢量就是协方差矩阵的最小特征值所对应的特征矢量,从而引入次分量分析(MCA)寻找最优权矢量,因此该恒模算法称为MCA-CMA算法.仿真结果充分验证该算法的有效性.     

Sequential Extraction of Minor Components

Principal component analysis (PCA) and Minor component analysis (MCA) are similar but have different dynamical performances. Unexpectedly, a sequential extraction algorithm for MCA proposed by Luo and Unbehauen [11] does not work for MCA, while it works for PCA. We propose a different sequential-addition algorithm which works for MCA. We also show a conversion mechanism by which any PCA algorithms are converted to dynamically equivalent MCA algorithms and vice versa.     

普适计算安全体系结构模型研究与设计

根据目前国际上普适计算研究的现状和发展趋势--国际上对普适计算的研究主要集中在人机接口和上下文感知计算等领域,国内对普适计算的研究主要集中在多模态的智能空间领域.提出了一个普适计算安全体系结构的参考模型,并简要讨论了该参考模型的3个关键研究内容--安全系统层、安全计算层和安全协同层.最后列举了一个模型实例.