辐射度算法在动态虚拟环境中的应用研究

本文研究了在静态曲面环境辐射度算法基础上的动态环境辐射度算法，并提出了判断景物阴影相交的中心点法和锥体相交法，最后讨论了如何用面向对象的方法实现本算法。     

基于改进动态规划的无人机搜寻航迹规划研究

针对传统动态规划算法在无人机航迹规划中存在耗时长以及冗余节点的问题,提出了一种基于多阶段决策的改进动态规划算法。在单向动态规划算法中加入双向策略,结合顺序法和逆序法以减少搜寻空间的状态总数;利用区间单调性和四边形不等式进一步减少每次决策涉及的状态点,得到优化后的状态转移方程,降低了搜寻的时间复杂度。最后,对改进动态规划算法与遗传算法、传统动态规划算法进行了数值仿真,结果表明,改进动态规划算法规划节点更少、计算时间更短。研究结果为无人机航迹规划的优化方案提供了一种解决方法。     

个性化推荐系统中的用户建模及特征选择

提出了一种基于向量空间模型的用户模型表示及其动态学习算法，研究了用户建模中的特征选择，提出了一种根据词性标注信息将词频法和TFIDF方法相结合的特征选择方法。实验结果表明这种动态学习算法能实时捕捉并记录用户最新的兴趣需求，从而准确地推荐出符合用户兴趣的信息，同时这种基于词性标注的组合特征选择方法的效果好于单独使用词频法或TFIDF方法。     

基于遗传和禁忌搜索算法求解车间调度优化问题

针对柔性生产环境下的车间调度问题,在考虑遗传算法早熟收敛问题和禁忌搜索法自适应优点的基础上,将遗传算法和禁忌搜索法结合起来,提出了基于遗传和禁忌搜索的混合动态优化调度算法,并用实例对该算法进行了仿真研究。结果表明,此算法有很好收敛精度,是可行的，并且能够在扰动发生后提供新的调度计划，与传统的调度算法相比较，体现了明显的优越性。     

交互式动态体绘制及其加速算法

体绘制三维成象法是一门新兴的3D采样数据场可视化技术，在医学成象和科学可视化领域有着极为广泛的应用，但由于3D数据量大，其使用往往受到巨大计算开销的限制，因此很多研究人员致力于静态体绘制加速算法的研究，并解决医学图象三维可视化中三维体数据显示速度与成象质量问题，因而提出了一种交互式动态体绘制算法，即从任意的视点距离和视线方向进行动态编制，并在分析其算法复杂度的基础上，提出一种新的加速算法，同时使得动态体绘制过程几乎达到实时的效果，经验证，这种算法比标准算法快4～5倍。     

工作流管理系统的流程柔性动态变更研究

为解决工作流管理系统中流程柔性演进变化问题，结合业务模型生命周期和业务流程模型变更管理的特点，提出了一个支持业务流程动态更新模型和业务流程实例动态迁移算法。在该算法中引入区域划分法，在迁移之前进行相关数据一致性检查和影响区域比较，通过该算法实现流程实例动态调整，以适应新的变种。最后基于该算法和一工作流管理系统平台，通过一个案例来演示业务流程动态更新的过程。     

一种综合的基音提取方法

本文提出了一种综合的基音提取算法，综合运用了平均幅度差法、自相关函数法和简单逆滤波器跟踪法等多种算法对候选的基音频率点进行打分，最后再用动态搜索的算法找出一条全局最优路径。从而避免了单一方法的局限性，取得了很好的性能。     

用动态规划法求解0-1背包问题

0-1背包问题是算法分析中的著名问题,有重要的使用价值,是算法研究的热点。目前较成熟的常用算法有贪心算法、动态规划、回溯法、分枝-限界法等。本文主要通过动态规划原理来求解0-1背包问题。     

基于手势识别的机器人人机交互技术研究

研究了基于视觉的动态手势识别技术,采用基于肤色的高斯模型与改进的光流场跟踪算法结合的方 法,实现了复杂背景下实时的手势跟踪,具有快速和准确的特点,且具有较好的鲁棒性．对于动态手势识别器,采 用了隐马尔可夫模型（HMM）作为训练识别算法．考虑到动态手势特征本身的一些特点,对HMM 参数优化算法重 估式加以修正,调整了算法比例因子,从而推导了最佳状态链的确定算法、HMM 参数优化算法．最后将研究开发 的动态手势识别算法成功地应用到了基于网络的远程机器人控制系统中．     

一种基于带宽和时延的流量工程动态路由选择算法

在流量工程的路由选择模式中动态路由选择算法最重要。本文研究了多种动态路由选择算法后，提出了一种基于带宽和时延的流量工程动态路由选择算法，并通过实际仿真，验证了该算法的有效性和便利性。     

开放式计算环境中一个新的声誉建立方法

归纳了目前信任管理领域中声誉建立的方法,分析其不足之处并提出了一种新的声誉建立方法。该方法综合利用了拓扑信息和反馈信息,用于开放式计算环境中声誉的建立。将该方法与当前的方法进行了分析和对比。该方法可以有效地处理开放式计算环境中反馈信息少和动态性的问题,与当前方法相比,该方法更为有效。     

动态数学模型算法研究

该文研究了计算机仿真中具有代表性的微分环节和惯性环节动态数学模型的计算方法，通过理论分析和数学推导，找到影响计算精度的动态因子，给出动态因子的计算公式及计算方法，从而提高了此类模型的计算精度。     

Computerized analytical solutions in dynamic programming

This paper concerns the computerized computation of analytical solutions to certain dynamic programming problems. The method is an algebraic approach as opposed to the discrete grid approximation technique typically used in dynamic programming. The algebraic approach, where applicable, has considerable computational advantages over the grid method.

The problems considered are those with additive quadratic returns, linear transitions, a single state variable, and a decision variable per stage. Both convex and nonconvex returns are allowed, as well as certain nonserial stage structures. An analytical procedure for quadratic problems and its implementation in a computer program are discussed. Comparisons between the analytical approach and grid approximation methods are made with respect to computational time and accuracy. Because of the computational attractiveness of the analytical approach, it has potential for use in approximation schemes for more general dynamic programming problems.     

Dynamic gradient approaches to compute the closest unstable equilibrium point for stability region estimate and their computational limitations

The reflected gradient method and the Newton trajectory method are approaches to compute the closest unstable equilibrium point (UEP) for stability region estimation. We address the computational issues involved in these methods. We first suggest a dynamic gradient approach as a unified and extended version of these methods. Then, we show that computing the closest UEP using the dynamic gradient approach can be infeasible.     

基于聚类的背景建模与运动目标检测方法

为克服目前动态背景建模方法中计算量和存储量大的问题,提出了一种基于聚类的动态背景建模与运动目标分割方法。由于动态背景下每个像素的取值在时间轴上呈多峰分布形式,因此将每个峰看成一个子类,用聚类技术快速实现了动态背景的建模与更新,然后利用建立的背景模型快速、准确地实现运动目标的分割。实验结果表明:提出的背景建模方法能有效捕获并适应背景的动态变化,可显著降低目前动态背景建模方法的计算量和内存需求量,易于在基于DSP或FPGA等硬件系统上实时实现。     

Time history dynamic analysis of structures using filter banks and wavelet transforms

Dynamic analysis of structures is achieved by wavelet transforms and filter banks. The method reduces the computational burden of the large-scale dynamic analysis. A time history analysis is carried out for a seismic analysis. To reduce the computational work, fast wavelet transform is used. To compute fast wavelet transforms, the Mallat and the Shensa algorithms are used. These two methods are used for wavelet theory together with filter banks. The low and high pass filters are used for the decomposition of accelerogram ground acceleration into two parts. The first part contains the low frequency of the record, and the other contains the high frequency of the record. The low frequency content is the most important part; therefore this part of the record is used for dynamic analysis. A number of structures are analysed and the results are compared with dynamic analysis using the original earthquake record.     

基于计算实验的城市道路行程时间预测与建模

城市道路行程时间预测对于提高交通管控效果具有重要意义. 本文综合应用平行系统、集散波、误差反馈修正、多模型自适应控制及模型库动态优 化策略等方法与技术对间断流行程时间预测问题进行了研究. 首先,介绍了平行系统理论的基本原理及计算实验的基本方法; 然后,给出了基于平行系统理论的路段行程时间的预测模型, 设计了基于集散波的行程时间计算实验方法, 提出了多模型自适应行程时间预测并给出了模型动态优化策略. 最后,通过实验证明了本方法的有效性. 结果表明, 本文方法预测精度较高, 且能够对行程时间预测值进行持续优化, 可为后续的间断流行程时间预测研究提供借鉴.     

Reinforcement learning for resource allocation in LEO satellite networks.

In this paper, we develop and assess online decision-making algorithms for call admission and routing for low Earth orbit (LEO) satellite networks. It has been shown in a recent paper that, in a LEO satellite system, a semi-Markov decision process formulation of the call admission and routing problem can achieve better performance in terms of an average revenue function than existing routing methods. However, the conventional dynamic programming (DP) numerical solution becomes prohibited as the problem size increases. In this paper, two solution methods based on reinforcement learning (RL) are proposed in order to circumvent the computational burden of DP. The first method is based on an actor-critic method with temporal-difference (TD) learning. The second method is based on a critic-only method, called optimistic TD learning. The algorithms enhance performance in terms of requirements in storage, computational complexity and computational time, and in terms of an overall long-term average revenue function that penalizes blocked calls. Numerical studies are carried out, and the results obtained show that the RL framework can achieve up to 56% higher average revenue over existing routing methods used in LEO satellite networks with reasonable storage and computational requirements.     

Fast generation of 3-D deformable moving surfaces

Dynamic surface modeling is an important subject of geometric modeling due to their extensive applications in engineering design, entertainment and medical visualization. Many deformable objects in the real world are dynamic objects as their shapes change over time. Traditional geometric modeling methods are mainly concerned with static problems, therefore unsuitable for the representation of dynamic objects. Apart from the definition of a dynamic modeling problem, another key issue is how to solve the problem. Because of the complexity of the representations, currently the finite element method or finite difference method is usually used. Their major shortcoming is the excessive computational cost, hence not ideal for applications requiring real-time performance. We propose a representation of dynamic surface modeling with a set of fourth order dynamic partial differential equations (PDEs). To solve these dynamic PDEs accurately and efficiently, we also develop an effective resolution method. This method is further extended to achieve local deformation and produce n-sided patches. It is demonstrated that this new method is almost as fast and accurate as the analytical closed form resolution method and much more efficient and accurate than the numerical methods.     

组合结构等效阻尼比的确定及 在有限元计算中的应用

针对组合结构动力响应计算中,一般根据工程经验确定结构阻尼比,往往导致结构动力响应计算结果偏小,不利于结构安全评估的问题,首先根据复阻尼理论与结构动力学方法,推导出组合结构的等效阻尼比计算公式;然后,以某体育场组合结构为工程背景,在有限元法基础上使用ANSYS软件建立该结构的有限元模型.根据计算出的自振特性以及利用ANSYS二次开发功能所形成的阻尼刚度矩阵,实现等效阻尼比的有限元法求解.计算结果表明,等效阻尼比能够正确反映组合结构的动力特性,从而可以科学地计算其动态响应.