基于模糊切换的配浆过程智能控制研究

基于配浆浓度控制过程是一个突发干扰、时变以及超调量大的过程,设计了一种基于模糊切换的配浆浓度智能控制方法。该方法将模糊控制和免疫PID控制相结合,采用模糊切换方法实现了两种控制器的协调输出,兼顾了快速性、准确性和稳定性,抑制配浆过程中出现的突发干扰和超调量。实际运行结果表明,该算法提高了配浆过程中浓度控制的快速性,避免了系统超调量的影响,保证了系统的稳定性和鲁棒性,完全能满足配浆过程浓度的工艺要求。     

软件实现主备倒换的设计

提出了一种软件实现通信系统主备倒换的改进机制,并且适用于多模软基站通信系统。一方面,数据同步和链路切换不再同时进行,数据同步放在了预倒换阶段,从而大大缩短了主备倒换时间;另一方面,备倒主(备状态切换为主状态)先于主倒备进行,即不允许出现软件双备的情况,保证系统在任何情况下都有可用的主控板。并且该机制适用于未来基站的发展趋势——多模软基站通信系统,针对于正常倒换和异常倒换两类情况,通过倒换条件判断,预倒换、备倒主、主倒备的顺序完成主备倒换来实现主备之间的快速可靠切换。并且该机制对倒换失败的情况做了恰当的处理。     

无人直升机悬停至前飞切换控制

模态切换控制是无人直升机实现全天候自主飞行的关键,实现飞行模态闯快速平稳的切换是无人直升机控制器设计的主要目的。针对无人直升机悬停至前飞过切换程时高度不能保持现象和对象无人直升机高度一航向通道之间存在耦合,提出了前飞速度和航向角速率补偿设计高度通道控制律,升降速度和总距风扇联动关系补偿设计航向通道控制律。最后通过大量仿真试验验证了此方法的可行性和有效性。     

单神经自适应PSD 预测控制在过热汽温切换系统中的应用

提出一种基于单神经元自适应PSD(proportional sum differential)预测控制器的新型火电厂过热汽温切换控制系统.采用单神经元自适应PSD控制与Levinson预测器相结合的控制方式以改善大滞后、多干扰系统的控制特性,同时利用Foxboro公司I/A系列的DCS控制系统平台对其组态设计(包括无扰切换、前馈补偿以及抗积分饱和等),以实现手自动切换和各控制器之间的合理切换.实验室的多次仿真研究和某火电厂的现场运行均表明该控制系统具有良好的控制品质.     

Adaptive broadcast by fault-tolerant spanning tree switching

Adaptation is a desirable requirement in a distributed system as it helps the system to perform efficiently under different environments. For many problems, more than one protocol exists, such that one protocol performs better in one environment while the other performs better in another. In such cases, adaptive distributed systems can be designed by dynamically switching between the protocols as the environment changes. Distributed protocol switching is also important for performance enhancement, or fault-tolerance of a distributed system. In this work, we illustrate distributed protocol switching by providing a distributed algorithm for adaptive broadcast that dynamically switches from a BFS tree to a DFS tree. The proposed switching algorithm can also handle arbitrary crash failures. It ensures that switching eventually terminates in spite of failures and the desired tree (DFS tree) results as the output. We also investigate the properties that can be guaranteed on the delivery of broadcast messages under specific failure conditions. We show that under no failure, each broadcast message is eventually correctly delivered to all the nodes in spite of switching. Under arbitrary crash fault, we ensure that switching eventually terminates with the desired tree as the broadcast topology. We also investigate the specific delivery guarantees that can be provided when a single crash fault happens, both during switching and when no switching is in progress.     

Ultra‐fast‐switching flexoelectric liquid‐crystal display with high contrast

Abstract— The flexoelectro‐optic effect provides a fast‐switching mechanism (0.01–0.1 msec), suitable for use in field‐sequential‐color full‐motion‐video displays. An in‐plane electric field is applied to a short‐pitch chiral nematic liquid crystal aligned in the uniform standing helix (or Grandjean) texture. The switching mechanism is experimentally demonstrated in a single‐pixel test cell, and the display performance is investigated as a function of device parameters. A contrast ratio of 2000:1 is predicted.     

Highly efficient switched‐mode transmitter using a current mode class‐D RF amplifier

This article presents a switched‐mode transmitter architecture using a current mode class‐D (CMCD) amplifier. To achieve high average efficiency for a modulated signal the envelope of the complex baseband signal is transformed into pulses such that the CMCD amplifier is operated either at its peak efficiency or completely switched off. The CMCD amplifier has been designed based on single‐tone active harmonic load‐pull measurements to achieve a power‐added efficiency (PAE) of 61.5% with 25 W output power at 900 MHz using LDMOS FETs. Removing the losses of the demodulation filter and of the amplifier a 10% higher efficiency than in an ideal class‐B amplifier can be obtained for burst‐mode operation with a peak‐to‐average power ratio of 10 dB. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

可靠实现煤矿双机热备系统的方法

在分析商用双机热备系统在煤矿应用的局限性基础上,提出了一种适用于中小煤矿的双机热备系统纯软件实现方法。该方法采用单/双工混合运行模式保证双机实时性能和数据一致性,采用心跳线连接和对等网络消息传递机制实现运行故障监测与传递功能,采用数据自动同步技术减少人工干预和提高系统可维护性,并采用虚拟IP地址技术实现应用层透明访问和无缝切换功能。实验与应用案例证明该方法符合相关行业安全标准并具备现实可行性。     

Static timing analysis for modeling QoS in networks-on-chip

Networks-on-chip (NoCs) are used in a growing number of SoCs and multi-core processors. Because messages compete for the NoC’s shared resources, quality of service and resource allocation are major concerns for system designers. In particular, a model for the properties of packet delivery through the network is desirable. We present a methodology for packet-level static timing analysis in NoCs. Our methodology quickly and accurately gauges the performance parameters of a virtual-channel wormhole NoC without simulation. The network model can handle any topology, link capacities, and buffer sizes. It provides per-flow delay analysis that is orders-of-magnitude faster than simulation while being significantly more accurate than prior static modeling techniques. Using a carefully derived and reduced Markov chain, the model can statically represent the dynamic network state. Usage of the model in a placement optimization problem is shown as an example application.     

一体化承载网络体系架构研究

传统信息网络因面向业务支撑设计而造成体系架构的刚性,无法满足业务发展多样性和网络异构的需求,因此无法适应下一代网络融合、可扩展等特点.面向服务提供的技术体系可以解决这一问题.文中以网络承载服务为核心,以可重构路由交换平台为关键支撑技术,设计出一种面向服务提供的网络体系架构--一体化承载网络(UCN)模型,以及基于UCN模型设计出的逻辑承载网的资源均衡构建算法(RBCA)并进行了网络仿真及结果分析,为下一代网络的研究和设计提供了新的思路.