嵌入式操作系统进程监测器的设计与实现

为避免嵌入式操作系统的进程受到恶意软件的修改破坏,提出一种适合于嵌入式操作系统的进程监测器。监测器周期性地对系统进程控制块进行检测恢复,通过设置进程检查点为系统提供恢复操作进程,并在Linux上进行实现,给出主要的数据结构和实现过程。实验结果表明,监测器的运行对系统性能影响小,能对系统进程进行有效的检测恢复。     

基于标记点检测的视线跟踪注视点估计

传统的头戴式视线跟踪系统需要借助额外的头部位置跟踪器或其他辅助设备才能定位视线方向.针对该问题,提出一种基于标记点检测的注视点估计方法.该方法通过计算机视觉的方法检测标记点,建立场景图像与真实场景中计算机屏幕之间的空间关系,将场景图像中的注视点坐标映射到计算机屏幕中.实验结果表明,该方法简单易行,可以较好地估计出用户在...     

基于神经网络的鲁棒NLOS误差抑制算法

提出一种基于Kalman滤波器和神经网络(NN)的非视距(NLOS)误差抑制算法。根据到达时间(TOA)测量值的特点和NLOS误差的统计特性,推导出Kalman滤波器输出无偏估计所需满足的条件,利用NN估计该条件中的环境参数,实现NLOS误差抑制。仿真结果表明,该算法在估计精度和算法鲁棒性方面均具有较好的性能。     

网络心跳包序列的数据流分簇检测方法

在对网络会话进行时序分析的基础上,提出基于数据流分簇处理的心跳包序列检测方法。对数据流进行时序分簇处理,按周期性特征扩充簇集合,筛除不符合特征的簇对象,根据稳定的簇集合检测心跳包序列。实验结果表明,该方法检测率较高、误检率较低,能够实现实时检测和处理。     

入侵检测中的数据约简研究

为解决入侵检测中的数据约简问题,提出一种基于粗糙集的入侵检测数据约简算法,其中包括特征选择与属性值约简。特征选择部分采用互信息的方法消除冗余特征,属性值约简部分采用归纳值约简算法消除冗余属性值。实验结果表明,该方法不仅能缩短训练及检测时间,减小数据存储代价,还能提高分类精确度。     

一种用于帧频提升系统的运动估计算法

基于静止检测、运动矢量预测,结合局部全搜索和下采样方法,提出一种有效的运动估计算法。将该算法用于基于运动估计运动补偿的帧频提升系统中。实验结果表明,该算法在减少计算量的同时,保证了内插帧有较高的主客观质量,能减少搜索点数,同时保持较高的搜索准确度。     

一种基于最小均方误差原理的位同步捕捉算法

提出一种数字通信系统中基于最小均方误差原理的位同步捕捉算法,对算法的提出、原理以及性能进行了理论分析,同时在加性高斯白噪声信道下进行了大量的计算机仿真,给出了在某无线通信系统中的应用结果.此算法通用性强,实现位同步捕捉速度快,易于高速单片机及DSP实现,具有良好的抗噪性能.     

基于虚拟机的运行时入侵检测技术研究

入侵检测技术通常分为误用检测和异常检测两类,误用检测根据攻击模式库检测已知的攻击行为,但却难以防范未知的攻击行为;异常检测技术虽然可以预测偏离正常值阈区间的潜在攻击行为,但却存在较高的误报现象。在虚拟机监视器中对虚拟机操作系统的运行行为进行带外监控,避免了操作系统内监控模块被病毒感染的难题;通过监视虚拟机的运行时行为,对之作组合序列的合法性分析,扩展了误用检测防范长时间段攻击行为的能力,识别通过合法系统调用进行的恶意攻击。测试数据表明,该技术能够较好地检测出复杂组合攻击行为。     

A new strategy for defect inspection by the virtual inspection in semiconductor wafer fabrication

The defect of process equipments is a major factor that impairs the yields in the mass production of semiconductor wafer fabrication and it is a main supervision means to use high-resolution defect inspection tools to detect and monitor the defect damage. Due to the high investment costs of these inspection tools and the resulting decrease in the throughput, how to improve the sampling rate is an important issue for the associated inspection strategy. This paper proposes a new concept and implementation of virtual inspection (VI) to enhance the detection and monitoring of defect in semiconductor production process. The underlying theory of the VI concept is that the state variables identifications (SVIDs) of process equipments can reflect the process quality effectively and loyally. The approach of VI is to combine the application of the fault detection and classification (FDC), and the defect library and the re-engineering of inspection procedure to reach the full-scope of strategic objective. VI enables the defect monitoring to enter a new era by promoting the monitoring level of defect inspection from the previous lot-sampling basis to the wafer-sampling level, and hence upgrades the sampling strategy from random-sampling to full and right-sampling. In this study, various typical defect cases are utilized to illustrate how to create VI models and verify the reliability of the proposed approach. Furthermore, a feasible architecture of the VI implementation for mass production in semiconductor factory is presented in the paper.     

Numerical method using cubic B-spline for the heat and wave equation

In the present paper, the cubic B-splines method is considered for solving one-dimensional heat and wave equations. A typical finite difference approach had been used to discretize the time derivative while the cubic B-spline is applied as an interpolation function in the space dimension. The accuracy of the method for both equations is discussed. The efficiency of the method is illustrated by some test problems. The numerical results are found to be in good agreement with the exact solution.