基于单神经元PID控制器的压电陶瓷控制方法

卫星地面综合测试是卫星研制过程中的重要环节,对系统功能验证及性能评估具有重要作用。传统的卫星地面综合测试系统存在研制周期长、投入较大、自动化流程不够完整、可重用性较差等不足。而北斗导航卫星地面综合测试系统采用分布式、高实时性、可配置、多主机的集成体系结构,是集计算机通讯、实时控制、实时数据处理、事后分析等功能于一体的测试系统,适用于从卫星总装集成到发射各个阶段的电气测试。通过卫星系统级的各项接口、功能、性能指标测试,表明该系统满足支持系统论证、状态确认、问题排查等测试需求,有力支撑了北斗导航卫星的成功发射和在轨运行。     

基于GA的主汽温系统内模控制研究

主汽温控制系统是典型的大迟延、大惯性、时变控制系统,一直以来都是火电厂自动控制的难点。为此将内模控制引入主汽温控制系统,并提出采用遗传算法对滤波器参数优化整定,该方法简单易行,相较于传统PID参数整定方法具有一定的优越性。并对内模控制为主控制器的IMC-PI控制系统进行SIMULINK仿真,与PID-PI控制系统进行对比,仿真结果表明IMC-PID控制系统相比于传统PID-P串级控制系统过渡时间短、超调量小、鲁棒性好等特点。其控制效果好于常规串级 PID 控制系统,适用于大迟延、大惯性过程的控制,并且易于在工业上实现。     

稀有气体卤化物准分子激光器工作气体实时补给技术

为延长稀有气体卤化物准分子激光器工作气体使用寿命,在原有供气设备基础上增加了工作气体实时补给技术.该技术采用FPGA控制系统将逐步提高放电电压、补充卤素气体和更换部分混合气体等操作有效组合起来.随着激光脉冲能量的下降,逐步提高放电电压;当放电电压达到最大值时,开始补充卤素气体,并恢复放电电压;当补充卤素气体效果不明显时,更换部分混合工作气体.将该技术应用于医用型ArF准分子激光器中进行实验研究,结果表明:在没有使用工作气体实时补给技术的情况下,激光器累计工作14.38 h后,输出单脉冲激光能量下降了17.2％;采用工作气体实时补给技术后,激光器输出能量下降速率明显降低,累计工作14.38 h,其单脉冲能量下降率能控制在3％范围内.因此,采用该技术可延长激光器工作气体的使用寿命、提高输出激光能量稳定性、减少停机次数并降低运行成本.     

Dynamics and optimal control in a spatially structured economic growth model with pollution diffusion and environmental taxation

In the first part of this paper we present a spatially structured dynamic economic growth model which takes into account the level of pollution and a possible taxation based on the amount of produced pollution. In the second part we analyze an optimal harvesting control problem with an objective function composed of three terms, namely the intertemporal utility of the decision maker, the space–time average of the level of pollution in the habitat, and the disutility due to the imposition of taxation.     

Characterization of sequence variation at 30 autosomal STRs in Chinese Han and Tibetan populations

Massively parallel sequencing (MPS) technologies have the ability to reveal sequence variations within STR alleles as well as their nominal allele lengths, which have traditionally been detected by CE instruments. Recently, Thermo Fisher Scientific has updated the MPS-STR panel, named the Precision ID GlobalFiler next-generation sequencing (NGS) STR Panel version 2, with primers redesigned to add two pentanucleotide tandem repeat loci and profile interpretation supported by the Converge software. Using the Ion Chef System, the Ion S5XL System, and the Converge software, genetic variations were characterized within STR repeat and flanking regions of 30 autosomal STR markers in 115 unrelated individuals from two Chinese population groups (58 Tibetans and 57 Hans). Nineteen STRs demonstrated a relative increase in diversity with the variant sequence alleles compared with those of traditional nominal length alleles. In total, 390 alleles were identified by their sequences compared with 258 alleles that were identified by length. Of these 92 sequence variants found within the STR repeat regions, 40 variants were located in STR flanking regions. Additionally, the agreement of the results with CE data was evaluated, as was the ability of this new MPS panel to analyze case-type (11 samples) and artificially degraded samples (seven samples in triplicate). The results generated from this study illustrate that extensive sequence variation exists in commonly used STR markers in the selected population samples and indicate that this NGS STR panel has the potential to be used as an effective tool for human forensics.     

SoC、DFM与EDA

介绍了系统级芯片(SoC)、可制造性设计(DFM)和电子设计自动化(EDA)的最新发展动态。SoC正在从单核向双核、四核和多核过渡。SoC设计必须采用DFM和EDA。采用DFM和EDA的优点:(1)提高芯片的生产效率和良率;(2)降低芯片生产成本;(3)缩短芯片生产周期,加速上市。     

产品开发活动中文件和记录的控制

本文论述了在产品开发过程中,文件的分类,文件的有效性控制、技术性控制、管理性控制的内容和控制方法,以及记录的控制要求和方法.     

AN ENHANCEMENT SCHEME OF TCP PROTOCOL IN MOBILE AD HOC NETWORKS： MME-TCP

Transmission Control Protocol （TCP） optimization in Mobile Ad hoc NETworks （MANETs） is a challenging issue because of some unique characteristics of MANETs. In this paper, a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP （MME-TCP） designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore, these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs.     

A MAC protocol to support hybrid antennas in a wireless LAN

Hybrid Distributed Coordination Function （HDCF）, a modified medium access control protocol of IEEE 802.11 standard, is proposed in this paper to support both smart adaptive array antennas and normal omni-directional antennas simultaneously in one wireless LAN. Omni-directional antennas follow the standard Distributed Coordination Function （DCF） and smart antennas follow the Directional DCF （DDCF）. The proposed DDCF is based on Hybrid Virtual Carrier Sense （HVCS） mechanism, which includes Omni-directional Request-To-Send/Clear-To-Send （ORTS/OCTS） handshake mechanism and directional data transmission. HDCF is compatible with DCF. When a node transmits in a directional beam, the other nodes can multiplex the physical channel. Hence, HDCF supports Space Division Multiple Access （SDMA）. Simulation results show that HDCF can support hybrid antennas effectively and provide much higher network throughput and lower delay and jitter than DCF does.     

基于多端口存储器互连结构的多处理器系统芯片设计

多处理器系统芯片设计的关键问题之一是微处理器之间的互连结构.在总线互连结构和开关互连结构之后,提出了基于多端口存储器的第3种互连结构.利用VHDL进行了多时钟多端口存储器设计,并利用EDA工具进行了片上系统芯片的多微处理器数据通讯的功能仿真.分析了基于总线、基于开关、基于多端口存储器的3种互连结构的特点.研究表明基于多端口存储器的互连结构具有异步数据传输,数据缓冲功能;具有数据传输延时小,多微处理器系统芯片的拓扑阵列规模可扩展的优点.