多网络融合的水厂自动化控制系统设计

针对水厂仪表可集成度低和网络兼容性差的缺点,设计了一种多网络融合的水厂自动化控制系统。系统节点选用Microchip公司基于M4K内核的处理器PIC32MX795F512L,使用该芯片内置的多种网络接口与仪表／设备互连,并给出了硬件方案、工业以太／CAN网络冗余算法和异构网络的数据帧协议。该系统网络平台融合了安防等其他...     

Rough approximations based on intersection of indiscernibility,similarity and outranking relations

Rough sets theory has proved to be a useful mathematical tool for dealing with the vagueness and granularity in information tables. Classical definitions of lower and upper approximations were originally introduced with reference to an indiscernibility relation. However, indiscernibility relation is still restrictive for many applications. Many real-world problems deal with assignment of some objects to some preference-ordered decision classes. And, the objects are described by a finite set of qualitative attributes and quantitative attributes. In this paper, we construct the indiscernibility relation for the subset of nominal attributes, the outranking relation for the subset of ordinal attributes, and the similarity relation for the subset of quantitative attributes. Then the global binary relation is generated by the intersection of indiscernibility relation, outranking relation and similarity relation. New definitions of lower and upper approximations of the upward and downward unions of decision classes are proposed based on the global relation. We also prove that the lower and upper approximation operations satisfy the properties of rough inclusion, complementarity, identity of boundaries, and monotonicity.     

Robust observer–controller compensator design using the loop shaping design procedure and the algebraic method

This paper investigates robust observer‐controller compensator design using Vidyasagar's structure (VS). VS has a unit matrix parameter H similar to the Q parameter for the Youla–Kucera parameterization. VS can be designed based on the left coprimeness of the central controller in the H_∞‐loop shaping design procedure (H_∞‐LSDP) and therefore can preserve the intrinsic properties of the H_∞‐LSDP. This paper introduces algebraic methods to simplify the design of H in the VS controller by solving specific algebraic equations. In particular, the algebraic design of H can achieve two things. First, a dynamic H adjusts the tracking performance and yields the integral action. Second, a dynamic H rejects the input and output sinusoidal disturbances with known frequencies. These attributes are indications of the flexibility of the proposed method since the output‐feedback controller design of the H_∞‐LSDP cannot easily deal with such conditions. This paper discusses the achieved loop and the closed‐loop behavior of the system with VS, and also gives two numerical examples. The first example shows that the proposed method results in a better design in many aspects than the resulting from H_∞‐LSDP. The second example shows the application of the proposed method to rejecting input and output step disturbances, and input and output multiple sinusoidal disturbances, for which the H_∞‐LSDP can hardly be used. Copyright © 2009 John Wiley & Sons, Ltd.     

SOM‐based projection module for mobile displays

Abstract— The development of a compact, efficient VGA projection module to be embedded in mobile devices is reported. The design incorporates laser/laser diode (LD) light sources, Schlieren optics, and a one‐dimensional diffractive spatial optical modulator (SOM). During development, the optical parameters were determined and the relationships between the parameters to optimize the optical specifications were derived. The resulting optimized specifications enable us to manufacture two types of optical modu les as compact as 13 cc and with as little as 10% speckle contrast ratio.     

无人飞行器伺服系统余度控制接口的设计与实现

介绍了一种在无人飞行器中设计应用的伺服系统余度控制接口,该接口实现了数字总线和模拟量两余度接口控制,可有效提高伺服系统的可靠性和抗干扰能力;分析了无人飞行器机载伺服系统的结构组成和工作模式,选择了CAN总线作为机载数字通讯总线,论述了机载伺服系统余度控制接口的工作原理,同时给出了伺服控制器的硬件接口电路及软件工作流程;实验结果表明余度控制接口工作稳定,控制通道转换平稳,该接口能满足无人飞行器控制系统的要求。     

一种兼容IEEE1149.1接口的模拟电压监测器的应用

针对模拟电压监测的技术现状,提出以支持IEEE1149.1接口标准的模拟电压监测器进行电压监测电路设计;简要介绍了模拟电压监测器的基本结构、操作原理和应用方式;通过实际电压电路可测性设计方案的制定分析、实验和测试,说明了该电压监测器的优势和特点;同时,文中提出应用FPGA作为内建自测试(BIST)控制器执行监测操作,是边界扫描技术与BIST技术结合应用的一次创新;最后的应用结果表明,该监测器的使用为电路设计人员的可测性设计提供了一种新思路和参考方法.     

免疫Agents在网络故障诊断方法中的研究

针对传统的网络故障诊断方法普遍具有自适应差、误报率高等的不足,提出了一种结合免疫算法和agent技术的网络故障诊断方法。在分布式环境中,按照网络的不同特征和环境差异,利用不同功能、不同类别的agent进行故障诊断,同时各agent之间能够互相协作,彼此进行信息交流,和采集数据,从而对所获得的故障类型进行诊断。实验证明,该方法能够对网络故障类型进行有效的判定,对以后大型网络故障诊断是一个很好的借鉴。     

Data-driven testing methodology for RFID systems

A radio-frequency identification (RFID) system including hardware and software may be updated from time to time after first time deployment. To ensure the reliability of the system, extensive tests are required. However, enumerating all test cases is infeasible, especially when the tests involve time-consuming hardware operations. To solve this problem, we propose a testing methodology for RFID systems which does not enumerate all test cases but rather those which are representative. A clustering method is adopted in selecting representative test cases. Although a small number of selected test cases are run, we can still obtain a relatively high bug detection rate compared with running the enumerated test cases. Our extensive experiments show the efficiency and effectiveness of our testing methodology.     

一种基于人工神经网络的快速超分辨率方法

图像的超分辨率是指利用一幅或者多幅的低分辨率图像,通过相应的算法来获得一幅对应的清晰的高分辨率图像.针对现有的基于学习的超分辨率方法低效率的问题,提出一种基于人工神经网络的快速超分辨率方法,该方法试图利用人工神经网络学习到高分辨率图像和低分辨率图像之间的函数关系,其理论基础来自于人工神经网络能够很好地求解流形学习中高维流形和低维流形之间的映射关系.     

Piecewise Pseudo-Maximum Likelihood Estimation for Risk Aversion Case in First-Price Sealed-Bid Auction

In the literature, more and more clues show that the bidders indeed tend to risk averse. But as a good structure estimation procedure in first-price sealed-bid auctions, the traditional PPMLE (Piecewise Pseudo-Maximum Likelihood Estimation) approach is only applicable to the risk neutrality case. This study generalizes this approach to the risk aversion case, and obtains a simple estimation procedure for the Pareto family of private costs. In the procedure, the estimation order of distribution parameters of private costs is not important, which is different from the traditional PPMLE method. Though there is no unique estimator for θ ₁ and γ, some guidance is given for real-world applications on the basis of our Monte Carlo simulation experiments. What’s more, this procedure can be reduced further, if one is only interested in estimating the private costs. Extensive simulation experimental results indicate that our approach outperforms or matches at least the traditional one in the case of risk neutrality, and is applicable to the risk aversion case.