防控车辆追尾智能技术

针对驾驶员控制安全车距所存在的致命弱点,提出并建立一种车辆智能测算前后相邻车辆间距的智能装置与方法,实时控制车辆前后合理车距,因此能够有效避免车辆追尾或被追尾事故的发生。该项技术装置模块化,算法识别周期短,经实用证实系统具有较高运行可靠性。     

基于STC89C54RD+单片机的电子废弃物等离子体裂解炉石墨电极控制装置的设计*

实现以STC89C54RD+芯片为处理器,以ADC0804为模数转换芯片,以IRF7807构成的全桥电路为控制执行电路的石墨电极工作电压自动控制装置。介绍了装置的设计背景和组成模块的原理,以及实现各模块功能的程序设计思路,其中核心是自动控制石墨电极电压的程序设计。该装置可使电子废弃物等离子体裂解炉工作时电弧电压维持在用户设定的范围内。     

汽车RKE系统加密算法研究与应用

以AES加密算法作为基础,描述了一种适用于汽车RKE系统的单向消息认证码(MAC)协议,并且对AES的轮操作结构进行了优化设计,用查表算法代替乘法运算,使整个算法只需要用查表及加法两种操作就能实现。最后,以车身控制领域广泛使用的S12X单片机作为接收端载体,介绍了通过AES加密后的MAC码在双核构架上的高效实现方案。     

两大类形式化方略

阐述机器翻译的两大类形式化方略。其中,第一大类形式化方略涉及:编程语言和英语(自然语言);第二大类形式化方略涉及:二进制数与十进制数、十进制数与汉字中文、中文和英文(可换)三类双语协同变换,属于形式化及其拓展研究领域。其结果是:凸显了第二大类形式化方略。其意义是:揭示了其理论依据,并为含语言学在内的学科知识系统工程提供了广义双语信息处理技术,有利于母语为非英语的计算机用户改善人机对话的语言环境。     

H ∞ control for 2-D singular delayed systems

This article considers the problem of H _∞ control for two-dimensional (2-D) singular delayed systems in Roesser models. The problem to be addressed is the design of a state feedback controller such that the acceptability, internal stability and causality of the resulting closed-loop system is guaranteed and a prescribed H _∞ performance level is ensured. In terms of a linear matrix inequality (LMI), a sufficient condition for the solvability of the problem is obtained. A desired state feedback controller can be designed by solving a certain LMI. A numerical example is provided to demonstrate the application of the proposed method.     

Accelerating average consensus by using the information of second-order neighbours with communication delays

This article investigates the problem of accelerating average consensus in undirected and connected networks. The protocol using the information of second-order neighbours with communication delays is proposed and the delay effects on stability and the convergence speed are analysed, respectively, under an assumption about the network topologies. It is proved that, for appropriate communication delays, networks reach average consensus faster under the proposed protocol than the standard protocol using only the information of first-order neighbours. Finally, a simulation example is presented to illustrate the proposed results.     

Mixed output feedback of the finite frequency H∞ control for singularly perturbed system

This paper considers the H_∞ control problem for a class of linear singularly perturbed systems in the finite frequency range. A mixed output feedback controller comprising of a static output feedback controller and a dynamic output feedback controller is developed for the system stabilisation. Based on the generalised Kalman–Yakubovich–Popov (GKYP) lemma, the frequency-domain inequalities can be converted into linear matrix inequalities which are numerically tractable. Compared with the existing full frequency approaches, better results are obtained. Moreover, the selection methods of the cut-off frequencies in both low and high frequency ranges are extensively studied with a view to reduce the conservativeness in output feedback control design. Simulation results suggest the asymptotic validity of the main results in this paper.     

Networked predictive control of constrained linear systems with input quantisation

This article investigates the problem of stabilising predictive control for constrained systems, wherein communication from the controller to the plant input is through a digital channel subject to quantisation and delay. A novel model with structured norm-bounded uncertainties is proposed to describe control system with input quantisation. Under a multirate scheme, a delay compensation strategy is presented. The networked predictive control synthesis approach is developed by solving a finite receding horizon optimisation problem with free control moves. It is shown that the proposed predictive controller not only efficiently reduces the negative effects of the quantisation and communication delays but also guarantees the closed-loop stability and satisfies constraints. Finally, a simulation example illustrates the effectiveness of the derived method.     

Filtering method for SAR interferograms with strong noise

We develop a filtering method for SAR interferograms with strong noise based on the concept of the Vondrák filter and the commonly used Goldstein filter. The one‐dimensional Vondrák filter is first extended to two dimensions, and then utilized to smooth the Fourier spectra of overlapped interferogram patches. The smoothed spectra are then back‐transformed into the interferogram space. Experimental results with simulated and real datasets show that the proposed filter can eliminate up to 70% of noise in a SAR interferogram. The results also show a 15% to 35% improvement over some of the existing filters when the noise in an interferogram is strong, and the stronger the noise in an interferogram, the greater is the improvement.     

Multisatellite observations and numerical simulation of an along‐coast cumulus cloud line induced by sea‐breeze circulation

A coastal cumulus cloud‐line formation along the east coast of the USA was observed on a National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellite (POES) Advanced Very High Resolution Radiometer (AVHRR) satellite image from 17 August 2001. The cloud line starts to form at about 16:00 UTC (local 12:00 noon) and follows the coastline from Florida to North Carolina. The length and width of the cloud line are about 850 km and 8.5 km, respectively. A 15‐min interval sequence of NOAA Geostationary Operational Environmental Satellite (GOES) images shows that the cloud line maintains the shape of the coastline and penetrates inland for more than 20 km over the next 6‐h timespan. Model simulation with actual atmospheric conditions as inputs shows that the cloud line is formed near the land–sea surface temperature (SST) gradient. The synoptic flow at all model levels is in the offshore direction prior to 16:00 UTC whereas low‐level winds (below 980 hPa) reverse direction to blow inland after 16:00 UTC. This reversal is due to the fact that local diurnal heating over the land takes place on shorter time‐scales than over the ocean. The vertical wind at these levels becomes stronger as the land–SST increases during the summer afternoon, and the leading edge of the head of the inland wind ascends from 920 hPa to about 850 hPa in the 3 h after 16:00 UTC. Model simulation and satellite observations show that the cloud line becomes very weak after 21:00 UTC when the diurnal heating decreases.