一种启发式属性约简算法

本文在研究前人算法的基础上,采用分而治之的思想.考虑信息分布区域的不同对知识划分的影响.提出了两种改进的属性重要度定义;针对文献中加权平均属性重要度中,加权参数人为确定的局限性,对权数进行了改进.根据粗集的拓扑特征,构造了相应的启发式信息,最后,通过实例证明了算法的有效性.     

浅析基于B／S结构的信息系统的安全问题

安全问题是在设计B／S结构的信息系统时重点需要考虑的问题,本文分析了B／S结构的信息系统的安全隐患并提出了相应的对付策略。     

多媒体技术在“工程力学”教学改革中的应用

适应社会对应用型人才的需要,改变传统"工程力学"教学中存在的弊端,应用现代多媒体技术,加快应用型人才培养的步伐,从而缩短理论与实践的距离。     

信息系统工程监理简述

信息系统工程监理对大多数人来说还很陌生,目前国内甚至还没有一套完善的信息化建设项目的监理制度。但对信息化建设项目实施监理,毕竟是大势所趋,尤其是这一市场需求的大量存在,将极大地促进信息化建设项目监理市场的成熟。     

基于.NET2.0串行端口资源的PC机与FCS实验系统串口通信的设计

.NET2.0新增Serial Port类为串口通信提供了强大的工具。该文重点阐述将DCS改造为FCS实验装置后,上位机是如何利用这一工具实现与控制系统之间的数据通信,从而证明采用C#串行通信类可以使串行通信程序的设计具有更强的实用性和灵活性,使串口数据传输变得更方便和可靠。     

VLAN技术在校园网中的应用

校园网络中实施VLAN技术可以提高网络管理效率、性能、带宽及灵活性,同时还能控制广播风暴,提高校园网安全性能。该文对VLAN技术在网络构建中的应用作了介绍。     

SSI接口技术及其在音频处理中的应用

Synchronous Serial Interface（SSI）是一种可应用于数据发送和接收的全双工串行接口,广泛应用于各种串行设备的通信。本文分析了SSI的工作原理,并通过与音频编解码芯片TLV320DAC23的通信实例,阐述了它在音频处理中的应用。     

A MEMS Thermal Biosensor for Metabolic Monitoring Applications

This paper presents a microelectromechanical systems (MEMS) differential thermal biosensor integrated with microfluidics for metabolite measurements in either flow-injection or flow-through mode. The MEMS device consists of two identical freestanding polymer diaphragms, resistive heaters, and a thermopile between the diaphragms. Integrated with polymer-based microfluidic measurement chambers, the device allows sensitive measurement of small volumes of liquid samples. Enzymes specific to a metabolic analyte system are immobilized on microbeads packed in the chambers. When a sample solution containing the analyte is introduced to the device, the heat released from the enzymatic reactions of the analyte is detected by the thermopile. The device has been tested with glucose solutions at physiologically relevant concentrations. In flow-injection mode, the device demonstrates a sensitivity of approximately 2.1 muV/mM and a resolution of about 0.025 mM. In flow-through mode with a perfusion flow rate of 0.5 mL/h, the sensitivity and resolution of the device are determined to be approximately 0.24 muV/mM and 0.4 mM, respectively. These results illustrate that the device, when integrated with subcutaneous sampling methods, can potentially allow for continuous monitoring of glucose and other metabolites.     

Fabrication of Flexible Transducer Arrays With Through-Wafer Electrical Interconnects Based on Trench Refilling With PDMS

Flexible transducer arrays are desired to wrap around catheter tips for side-looking intravascular ultrasound imaging. We present a technique for constructing flexible capacitive micromachined ultrasonic transducer (CMUT) arrays by forming polymer-filled deep trenches in a silicon substrate. First, we etch deep trenches between the bottom electrodes of CMUT elements on a prime silicon wafer using deep reactive ion etching. Second, we fusion-bond a silicon-on-insulator (SOI) wafer to the prime silicon wafer. Once the silicon handle and buried oxide layers are removed from the back side of the SOI wafer, the remaining thin silicon device layer acts as a movable membrane and top electrode. Third, we fill the deep trenches with polydimethylsiloxane, and thin the wafer down from the back side. The 16 by 16 flexible 2-D arrays presented in this paper have a trench width that varies between 6 and 20 ; the trench depth is 150 ; the membrane thickness is 1.83 ; and the final substrate thickness is 150 . We demonstrate the flexibility of the substrate by wrapping it around a needle tip with a radius of 450 (less than catheter size of 3 French). Measurements in air validate the functionality of the arrays. The 250- by 250- transducer elements have a capacitance of 2.29 to 2.67 pF, and a resonant frequency of 5.0 to 4.3 MHz, for dc bias voltages ranging from 70 to 100 V.     

Robust Adaptive Backstepping Motion Control of Linear Ultrasonic Motors Using Fuzzy Neural Network

A robust adaptive fuzzy neural network (RAFNN) backstepping control system is proposed to control the position of an X-Y-Theta motion control stage using linear ultrasonic motors (LUSMs) to track various contours in this study. First, an X-Y-Theta motion control stage is introduced. Then, the single-axis dynamics of LUSM mechanism with the introduction of a lumped uncertainty, which includes cross-coupled interference and friction force, is derived. Moreover, a conventional backstepping approach is proposed to compensate the uncertainties occurred in the motion control system. Furthermore, to improve the control performance in the tracking of the reference contours, an RAFNN backstepping control system is proposed to remove the chattering phenomena caused by the sign function in the backstepping control law. In the proposed RAFNN backstepping control system, a Sugeno-type adaptive fuzzy neural network (SAFNN) is employed to estimate the lumped uncertainty directly and a compensator is utilized to confront the reconstructed error of the SAFNN. In addition, the motions at the X axis, Y axis, and Theta axis are controlled separately. The experimental results show that the contour tracking performance is significantly improved and the robustness to parameter variations, external disturbances, cross-coupled interference, and friction force can be obtained, as well using the proposed RAFNN backstepping control system.