用于三维图像恢复的广义点扩展函数

采用传统的摄像系统点扩展函数恢复三维图像,往往不能得到满意的结果。文中提出一种新的概念－广义点扩展函数,取代传统的摄像系统点扩展函数,用于三维图像恢复。首先给出广义点扩展函数的定义,它等于物体和场景到摄像系统的点扩展函数与摄像系统的点扩展函数的券积。然后给出物体和场景到摄像系统的点扩展函数估计。最后还给出采用广义点扩展函数恢复三维图像的实验结果。实验结果表明,采用广义点扩展函数恢复三维图像,比采用     

基于虚拟模糊集的PID参数整定器的仿真研究

该文中给出的模糊整定器是在虚拟模糊集概念的基础上实现的。该方法首先根据Ｚ－Ｎ整规则,按照过程的开环阶跃响应设置初始参数,然后基于闭环控制系统的响应特性,利用模糊系统精确整定控制器参数。模糊控制规则知识库由整定知识和专家经验规则构成。其中整定知识可通过对一典型过程的参数整定来自动提取。最后给出的数字仿真结果证明该方法的有效性。     

杯芳烃-SAW传感器检测有机磷响应特性研究

研究了以25-(硫代烷基烷氧基)-对叔丁基杯[4]芳烃自组装分子作为声表面波(SAW)化学传感器敏感膜材料的SAW双通道延迟线传感器对DMMP检测的敏感特性.实验结果表明杯芳烃-SAW传感器对DMMP有高的灵敏度、好的响应特性和重复性.     

局域网防火墙的设计与实现

本文设计与实现了局域网防火墙。首先阐述了防火墙的原理,然后分析防火墙系统总体设计,最后论述防火墙的设计与实现,并详述其具体实现的各个模块。     

基于网络环境下新课程高中英语阅读教学的实践研究

本文简析了基于网络环境下新课程高中英语阅读教学实践研究的理论基础与必要性,运用任务型教学途径,从网络英语课堂教学与课外阅读教学两方面进行探索,并进行了效能与问题分析。     

基于ARM9和Linux的机器人控制系统设计

以ARM9和嵌入式Linux为平台,采用光电码盘,解决了在ARM中无高速I/O外部脉冲计数寄存器情况下轮式移动机器人的速度检测问题,并利用积分分离的PID算法实现了速度调制。在嵌入式Linux操作系统中完成整个控制过程驱动的编写,并在测速和动态调速等关键实现上给出详细的介绍,最终实现智能机器人的闭环控制。     

Discrete surface Ricci flow

This work introduces a unified framework for discrete surface Ricci flow algorithms, including spherical, Euclidean, and hyperbolic Ricci flows, which can design Riemannian metrics on surfaces with arbitrary topologies by user-defined Gaussian curvatures. Furthermore, the target metrics are conformal (angle-preserving) to the original metrics. A Ricci flow conformally deforms the Riemannian metric on a surface according to its induced curvature, such that the curvature evolves like a heat diffusion process. Eventually, the curvature becomes the user defined curvature. Discrete Ricci flow algorithms are based on a variational framework. Given a mesh, all possible metrics form a linear space, and all possible curvatures form a convex polytope. The Ricci energy is defined on the metric space, which reaches its minimum at the desired metric. The Ricci flow is the negative gradient flow of the Ricci energy. Furthermore, the Ricci energy can be optimized using Newton's method more efficiently. Discrete Ricci flow algorithms are rigorous and efficient. Our experimental results demonstrate the efficiency, accuracy and flexibility of the algorithms. They have the potential for a wide range of applications in graphics, geometric modeling, and medical imaging. We demonstrate their practical values by global surface parameterizations.     

A distributed expansible authentication model based on Kerberos

There is a potential server bottleneck problem when the Kerberos model is applied in large-scale networks because the model uses centralized management. To enlarge its application scope, researchers must consider how to build a trust relation among those Kerberos servers located on different isolated domains, but have not provided a way to prevent the potential bottleneck that can occur with Kerberos servers. With the development of across-domain authentication techniques, the local server bottleneck problem has not been alleviated; in fact, it has become more serious.Adopting the rigorous binary tree code algorithm, we present an authentication model based on Kerberos. Compared with similar models, our model has several advantages. First, it overcomes the potential server bottleneck problem and can balance the load automatically. Second, it can process across-domain authentication and enlarge the authentication boundary. Finally, its authentication path is short, with no more than two Kerberos servers being involved when authenticating a user.     

Design of distributed compliant micromechanisms with an implicit free boundary representation

In this paper, a parameterization approach is presented for structural shape and topology optimization of compliant mechanisms using a moving boundary representation. A level set model is developed to implicitly describe the structural boundary by embedding into a scalar function of higher dimension as zero level set. The compactly supported radial basis function of favorable smoothness and accuracy is used to interpolate the level set function. Thus, the temporal and spatial initial value problem is now converted into a time-separable parameterization problem. Accordingly, the more difficult shape and topology optimization of the Hamilton–Jacobi equation is then transferred into a relatively easy size optimization with the expansion coefficients as design variables. The design boundary is therefore advanced by applying the optimality criteria method to iteratively evaluate the size optimization so as to update the level set function in accordance with expansion coefficients of the interpolation. The optimization problem of the compliant mechanism is established by including both the mechanical efficiency as the objective function and the prescribed material usage as the constraint. The design sensitivity analysis is performed by utilizing the shape derivative. It is noted that the present method is not only capable of simultaneously addressing shape fidelity and topology changes with a smooth structural boundary but also able to avoid some of the unfavorable numerical issues such as the Courant–Friedrich–Levy condition, the velocity extension algorithm, and the reinitialization procedure in the conventional level set method. In particular, the present method can generate new holes inside the material domain, which makes the final design less insensitive to the initial guess. The compliant inverter is applied to demonstrate the availability of the present method in the framework of the implicit free boundary representation.     

基于神经网络的光电系统空中目标威胁估计

结合光电干扰武器系统的工作过程,对影响目标威胁评估的各种因素进行了分析,讨论了常用威胁评估方法的缺点和不足,提出了基于神经网络的空中目标的威胁估计算法,利用神经网络良好的自适应能力和自学习能力,通过样本数据训练,确定各个因素之间的非线性复杂关系,并通过示例介绍了目标威胁值的解算过程;与层次分析法进行了比较,结果表明,神经网络可以很好地逼近各个因素之间的权重关系,提高了空中目标威胁估计算法的准确性和适应性。