传感器网络及其操作系统

介绍传感器网络的特点、网络配置和操作系统等几方面内容,指出存在主要问题,以便更好地开展相关研究工作.     

Wideband mobile antenna design based on artificial neural network models

A compact wideband planar monopole antenna is designed and optimized based on artificial neural network (ANN) models. The antenna is suitable for DCS, PCS, DECT, PHS, IMT‐2000, UMTS, and WLAN in mobile communication. The design time decreases dramatically due to using the ANN models. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 316–320, 2003.     

Odyssey: a high‐performance clustered video server

Video servers are essential in video‐on‐demand and other multimedia applications. In this paper, we present our high‐performance clustered CBR video server, Odyssey. Odyssey is a server connecting PCs with switched Ethernet. It provides efficient support for normal play and interactive browsing functions such as fast‐forward and fast‐backward. We designed a set of algorithms for scheduling, synchronization and admission control, which results in a high utilization of resources. Odyssey is able to deliver a large number of video streams. Copyright © 2003 John Wiley & Sons, Ltd.     

A fast and compact elimination method of empty elements from a double‐array structure

A double‐array is a well‐known data structure to implement the trie. However, the space efficiency of the double‐array degrades with the number of key deletions because the double‐array keeps empty elements produced by the key deletion. This paper presents a fast and compact elimination method of empty elements using properties of the trie nodes that have no siblings. The present elimination method is implemented by C language. From simulation results for large sets of keys, the present elimination method is about 30–330 times faster than the conventional elimination method and maintains high space efficiency. Copyright © 2003 John Wiley & Sons, Ltd.     

Reliable Robust Preview Tracking Control Against Actuator Faults

In this paper we provide a solution to the reliable robust preview tracking problem against actuator faults for discrete LTI systems with polytopic uncertainties. This solution is in terms of the solvability of linear matrix inequalities (LMIs). The method is based on multi‐objective optimization and LQ tracking performance indices. To avoid the conservativeness problem associated with using a common LMI solution for the normal case and the fault cases, different LMI solutions are used in the proposed method. Two iterative algorithms are proposed and compared. Numerical examples are used to show the effectiveness of the algorithms.     

Optimal design of optical performance of reflective ferroelectric‐ and anti‐ferroelectric liquid‐crystal displays

Abstract— In an in‐plane optical geometry, such that the average optic axis lies on the plane parallel to both substrates, the optical properties of a reflective ferroelectric liquid‐crystal (FLC) or antiferroelectric liquid‐crystal (AFLC) cell were studied within the framework of the 2 × 2 Jones matrix formalism. To obtain good achromaticity and high brightness, the cell parameters such as the molecular rotation angle and the effective phase retardation of the AFLC layer were optimized. The device performances of the AFLC cell were experimentally demonstrated in this geometry.     

A New Grade Carbon Black Produced by Thermal Plasma Process

This paper presents a new route about producing carbon black,by wich the natural gas cracking is carried out in the absence of oxygen thanks to an electric energy supply externally given by a plasma jet.The carbon black produced by this process has a narrow size distribution and a small average diameter of 38nm as well as a highly branched aggregate.The higher DBP value of 1.40ml/g shows it should be a high structure carbon black.The FTIR spectra shows that there are lots of aromatic c-c bonds and a large amount of nitrogen-coutaining functional groups on the carbon blacks surface,such as-NH,-CN as we3ll as -CH,-OH,-COOH groups.     

管控一体化网络和现场总线在水电站综合自动化中的应用

介绍了水电站综合自动化系统的网络结构 ,该网络用以太网实现了管理控制网络的一体化 ,用通信转接器、CAN总线和MODBUSRTU协议实现了现场设备的通信 ,形成了一个覆盖全站智能设备的网络     

A twin‐star hyperchaotic attractor and its circuit implementation

A very simple 4D system with a twin‐star hyperchaotic attractor is presented in this letter. Computer simulation is given to visualize the attractor, and a simple circuitry is designed for system implementation. Copyright © 2003 John Wiley & Sons, Ltd.     

平面形状和布置的一种统一的定性表示方法

基于广义Ｖｏｒｏｎｏｉ图式，提出了Ｖｏｒｏｎｏｉ骨架边的跨度和势的概念，给出了保持连通性的层次骨架的建构算法。