两种数据融合算法对扩散硅压力传感器的温度补偿

针对扩散硅压力传感器在实际应用中对温度存在交叉灵敏度的问题,文章采用改进的多维回归分析法和BP神经网络法两种实用的智能化数据融合方法对压力传感器输出进行处理,以消除非目标参量(温度)对传感器的影响;研究结果表明这两种方法均能有效地抑制交叉灵敏度,减小灵敏度温漂和零点温漂;由于这两种融合算法具有各自的特点,因此可应用于不同要求的智能传感器系统中。     

Optical coherence tomography used for security and fingerprint-sensing applications

Optical coherence tomography (OCT) is an emerging technology for high-resolution cross-sectional imaging of three-dimensional structures. In the past, OCT systems have been used mainly for medical applications, especially ophthalmological diagnostics. As the OCT system is capable of exploring the internal features of an object, the authors apply OCT technology to document security and fingerprint-based biometrics by directly retrieving the two-dimensional information form of a multiple-layer information carrier and internal human body objects. Since a typical depth-resolution of an OCT system is of micrometre scale, an information carrier having a volume of 20 mm times 20 mm times 2 mm could contain 200 mega-pixel images. On other hand, the technologies used in conventional biometrics can be easily fooled and tampered with by using artificial dummies, because these ID features are extracted only from the surface of the skin. Hence the use of OCT to explore the internal biometrics becomes increasingly important.     

New type X-ray mask fabricated using inductively coupled plasma deepetching

 The fabrication of X-ray masks is a critical and challenging process in LIGA technique. As inductively coupled plasma (ICP) deepetching appears to be the most suitable source for deep silicon etching, we fabricated a new type X-ray mask using this technique. In comparison with other types of X-ray masks, the mask we fabricated has the advantages of its low cost and its simple fabrication process. Desired microstructures have also been fabricated using this new type X-ray mask in LIGA technique. Received: 17 July 2000/Accepted: 4 September 2000     

增强现实技术在虚拟演播室系统中的应用

虚拟演播室是虚拟现实技术和视频合成技术相结合的产物,其场景是计算机生成的三维场景,由于人们对虚拟场景和复杂度的无限要求,使得场景的实时显示十分困难,使用基于图像的绘制技术构造虚拟空间能够较好地解决这个问题。在虚拟演播室中,演员需要与三维运动虚拟物体进行交互,运用增强现实技术,可以将三维虚拟物体与基于图象绘制的虚拟场景融合在一起。     

稠密数据库有趣规则的快速挖掘

目前,关联规则的挖掘算法主要用于非稠密数据,很少有挖掘稠密数据的算法,而现实世界中有许多数据是稠密的。由于现行的算法不适合稠 密数据的挖掘,本文定义了兴趣度函数,给出了挖掘稠密数据有趣关联的有效算法。该算法与以往不同的是提前过滤掉不满足约束的属性组合,因而提高了速度,同时,使发现的规则更有趣,更易理解。     

虚拟空间会议系统中视频合成技术的研究与实现

虚拟空间会议系统能够把所有与会者合成同一个虚拟会场中,从而构造一个能提供无缝的会场环境,眼神接触、凝视感知等普通多媒体会议系统不具备的虚拟协同工作环境。VST系统是我们刚刚完成的一个虚拟空间会议系统。视频合成技术是其实现的关键技术之一。本文介绍了VST系统中视频合成技术的研究与实现。     

Optimal Control of Two-Stage Discrete Event Systems with Real-Time Constraints

We consider discrete event systems (DES) involving tasks with real-time constraints and seek to control processing times so as to minimize a cost function subject to each task meeting its own constraint. When tasks are processed over a single stage, it has been shown that there are structural properties of the optimal sample path that lead to very efficient solutions of such problems. When tasks are processed over multiple stages and are subject to end-to-end real-time constraints, these properties no longer hold and no obvious extensions are known. We consider a two-stage problem with homogeneous cost functions over all tasks at each stage and derive several new optimality properties. These properties lead to the idea of introducing “virtual” deadlines at the first stage, thus partially decoupling the stages so that the known efficient solutions for single-stage problems can be used. We prove that the solution obtained by an iterative virtual deadline algorithm (VDA) converges to the global optimal solution of the two-stage problem and illustrate the efficiency of the VDA through numerical examples.

基于改进免疫遗传算法的电网故障诊断研究

针对电网故障的特点,应用一种改进的免疫遗传算法对电网故障进行研究。该算法能够较好地解决传统遗传算法的不足。通过引入新的交叉和变异率,更多考虑了种群的全局特征,采用动态自适应方式提取疫苗,避免了传统遗传算法收敛速度较慢的缺点。改进的算法本着优胜劣汰的思想,删除适值较低的抗体群,取而代之的是随机生成的部分新抗体,保持种群的多样性。建立一个新的目标函数,通过对一个电网的分析,验证了方法的有效性。