跨多种平台的OpenGL解决方案

阐述了跨平台的OpenGL解决方案,介绍了vividGL的系统架构、基本特性和应用领域。通过和同行业其他解决方案的比较,显示出了vividGL解决方案的优越性。     

Multiple Solutions for Blocking Probabilities in Asymmetric Networks

Polynomial systems for blocking probabilities on networks with dynamic routing are formulated. Two parameters in the coefficient field representing link capacity are varied. A region of parameter values is identified on which the system has two solutions with a probabilistic interpretation. The region is bounded by contours of the constant term coefficients in the characteristic polynomials of certain traceform matrices. This generalizes earlier work on multiple blocking probabilities in symmetric networks.This work was supported by NSF DMS-0200888 and by SAMSI under grant DMS-0112069.     

A Framework to Consider

Reviewed in this issue: James S. Tiller, The Ethical Hack: A Framework for Business Value Penetration Testing     

Finding Multiple Solutions to Elliptic PDE with Nonlinear Boundary Conditions

In this paper, in order to solve an elliptic partial differential equation with a nonlinear boundary condition for multiple solutions, the authors combine a minimax approach with a boundary integral-boundary element method, and identify a subspace and its special expression so that all numerical computation and analysis can be carried out more efficiently based on information of functions only on the boundary. Some mathematical justification of the new approach is established. An efficient and reliable local minimax-boundary element method is developed to numerically search for solutions. Details on implementation of the algorithm are also addressed. The existence and multiplicity of solutions to the problem are established under certain regular assumptions. Some conditions related to convergence of the algorithm and instability of solutions found by the algorithm are verified. To illustrated the method, numerical multiple solutions to some examples on domains with different geometry are displayed with their profile and contour plots.     

Number of Solutions for Motion and Structure from Multiple Frame Correspondence

Much of the dynamic computer vision literature deals with the determination of motion and structure by observing two frames captured at two instants of time. Motion prediction and understanding can be improved significantly, particularly in the presence of noise, by analyzing an image sequence containing more than two frames. In this paper, we assume knowledge of correspondence of points on the surface of an object which is moving with constant motion, i.e., constant translation and constant rotation around an unknown center. We give a new formulation of the problem and prove that the following results hold in general for the number of solutions to motion and structure values (i.e., values of translation, rotation, and depth):(a) For three point correspondences over three views, there are at most two solutions, only one of which has all positive depth values;(b) For two point correspondences over four views, there is a unique solution;(c) For one point correspondence over five views, there can be up to ten solutions;(d) For one point correspondence over six views, there is a unique solution.The method of solution for each of the above formulations requires the solving of a system of multivariate polynomials, whose coefficients are functions of the observed data. In order to determine the number of solutions to these systems, we use theorems from algebraic geometry which imply that under a few mild conditions, the number of solutions at one set of data points provides an upper bound on the number of solutions for almost all sets of data points.Thus a bound on the number of solutions is obtained when a single system is solved by a method such as homotopy continuation, which we use here.     

对教学资源库建设的思考

该文就教学资源库建设过程中面对的主要问题进行了思考,并在此基础上提出教学资源库的设计思路以及在教学资源库建设中还应注意的问题,希望能对教学资源库的建设发挥的一定的参考作用。     

系统思考变频泵的应用

分析了定压供水系统变频泵功耗和泵流量的一次方成正比，用系统思考的方法指出“一变多定”配置泵群应用的局限，提出高性能离心泵群实用变频控制方案。     

P3P问题的多解现象的概率研究

一般情况下,P3P问题可能出现1,2,3或4个解.但是,若3个控制点和摄像机光心这4点共圆,则会出现无穷多组解.利用"蒙特卡洛"方法模拟出P3P问题分别出现1,2,3,4个解的概率为0.9993,0.0007,0.0000,0.0000.结果论证了如下的事实,即在大多数情况下,P3P问题有唯一解.     

桥接多联邦系统信息转发存在的问题及解决方案

进行大规模仿真,尤其是广域网上的仿真演练,多联邦互联是必经之路。桥接成员是实现多联邦互联的一种有效途径,其需要对高层体系结构(HLA)的6大类服务在多联邦系统间进行转发。HLA联邦成员的行为模式可以分为普适的、有选择的、有关存在的。结合联邦成员的几类行为模式,该文分析了桥接多联邦系统信息转发过程中可能存在的问题,并给出了解决方案。     

部署虚拟化前需要思考的几个问题

服务器虚拟化最近已经成为人们关注的一个焦点。了解虚拟化的应用特点,以及认识部署虚拟化前应该考虑到的问题,可以避免用户因认识错误引起的盲目投资,对实施虚拟化技术具有十分重要的意义。     

Should Macroeconomic Policy Makers Consider Parameter Covariances?

Many macroeconomic policy exercises consider the mean values of parameter estimates but do not use the variances and covariances. One can argue that the uncertainty of these parameter estimates is sufficiently small that it can safely be ignored. Or one can take the position that this kind of uncertainty cannot be avoided no matter what one does. Thus it is just as well to ignore it while making policy decisions. In this paper we address both of these positions in the presence of learning and find that they are unconvincing. To the contrary, we find evidence that the potential damage from ignoring the variances and covariances of the parameter estimates is substantial and that taking them into account can improve matters.     

部署虚拟化前需要思考的几个问题

服务器虚拟化最近已经成为人们关注的一个焦点。了解虚拟化的应用特点,以及认识部署虚拟化前应该考虑到的问题,可以避免用户因认识错误引起的盲目投资,时实施虚拟化技术具有十分重要的意义。     

Consider the lowly 2×2 matrix

If you're into computer graphics, you have to love matrices, but sometimes matrices are so complicated. They have determinants, eigenvalues, singular value decompositions... . What does all this stuff really mean? What does it mean, for example, to take the square root of a matrix? How about the logarithm of a matrix? I have built up my intuition about matrices by playing extensively with the simplest form, the lowly 2×2 matrix. These almost look too simple to be interesting, but they show off most of the properties of larger matrices. Better yet, you can write out explicit formulas for quantities that are harder to compute for larger matrices. Even so, some of the derivations provided in this article are probably at the limit of most people's appetite for algebra     

Existence and Exponential Stability of Multiple Periodic Solutions for a Multidirectional Associative Memory Neural Network

The paper proposes several mathematical models of the multidirectional associative memory (MAM) neural network by analyzing its structure. A model of MAM with distributed delays is studied. Under some new assumptions on activation functions, 2^n₀[m/2]{2^{n_0[m/2]}} invariant subsets of MAM are constructed. Then the existence and the exponential stability of 2^n₀[m/2]{2^{n_0[m/2]}} periodic solutions located on invariant subsets are obtained by constructing a suitable Liapunov function and a Poincaré mapping. An estimating method of the exponential convergence rate is given. The obtained results are new to MAM neural networks. An example is given to illustrate the effectiveness of the results.     

Building Consortia-Based it Solutions: A Decision Support Architecture for Agencies in Multiple State Governments

Consortia-based IT solutions can be found in many industries, but they pose special management challenges. This article describes an example from the public sector in which the outcomes include a decision support architecture that facilitates within-organization and cross-organization data analysis and reporting, as well as a Web-based knowledge management store for participants. the author argues that the governance model, processes, and key success factors from this project can be useful for those embarking on multi-organizational projects in which highly autonomous units have incentives to participate.     

The Method of Multiple Scales: Asymptotic Solutions and Normal Forms for Nonlinear Oscillatory Problems

The method of multiple scales is implemented in Maple V Release 2 to generate a uniform asymptotic solutionO(ϵ^r) for a weakly nonlinear oscillator.In recent work, it has been shown that the method of multiple scales also transforms the differential equations into normal form, so the given algorithm can be used to simplify the equations describing the dynamics of a system near a fixed point.These results are equivalent to those obtained with the traditional method of normal forms which uses a near-identity coordinate transformation to get the system into the “simplest” form.A few Duffing type oscillators are analysed to illustrate the power of the procedure. The algorithm can be modified to take care of systems of ODEs, PDEs and other nonlinear cases.     

考虑公平和护士偏好的护士排班研究

针对护士排班问题涉及护士满意度的特点，在护士排班过程中加入护士偏好和公平的约束，寻求最优的排班表以增加护士的满意度。根据多目标问题的特点，采用粒子群多目标优化算法。在硬约束条件上，加入N班之后不能上A班和P班的约束，使护士在上N班之后能够得到足够的休息。在算法设计上，加入变异算子，扩大了粒子群的搜索空间。由于各优化目标之间存在一定的矛盾，用多目标决策理论可以更加科学客观地优化护士排班表。在最后的案例分析中，发现护士不同的偏好会产生不同的非劣解，因此在实际排班中，要充分考虑护士的偏好，以求出更加科学合理的排班表。     

关于都市水墨人物画的当代文化背景的思考

本文试图在深入了解当代都市水墨人物画的发展历程后对其做较为深入的分析与探究,重点探析当下多元化文化语境下、在大众文化的环境下,都市水墨人物画又该具有怎样的当代性特征。这对于了解当下都市水墨人物画的现状、发展以及它在当代中国画坛中的位置都有积极的意义。     

考虑速度对期望间距影响的车辆跟驰模型研究

为了真实地反映驾驶员在道路行驶中的车辆跟驰机理,使用相关性分析方法找出影响期望间距的关键因素,从而提出改进的基于期望间距的车辆跟驰模型(improved desired distance model,IDDM).利用NGSIM数据对IDDM和经典的Gipps车辆跟驰模型的参数进行了标定,之后对标定的模型进行评价.研究结果表明,前后两车的速度以及相对速度主要影响跟驰过程中驾驶员采用的期望间距;IDDM与传统Gipps模型相比,其加速度、速度与位置的仿真精度分别提高了0.24 m/s2、0.72 m/s、0.53 m,可以为车辆跟驰行为分析提供参考.     

关于我国反病毒技术发展的若干思考

通过调查、分析和比较国内外病毒、反病毒技术的发展情况,指出民族软件产业在反病毒技术方面的不足,并从管理上、技术上、策略上提出了相应的应变措施,希望能为我国民族软件业能在世界反病毒领域占有一席之地有所帮助。