媒体同步关系的描述

由于多媒体信息系统中，需要集成各种数据类型，而这些数据类型又有着密切的时间关系，所以对于多媒体来说，同步问题是很重要的，而同步的基础是为同步关系建立一个独立于实现环境的抽象的表示模型，本文着重讨论几种描述媒体同步关系的模型。     

汽轮机转子热应力在线计算灰色数学模型

热应力计算中边界条件、物性参数和初始条件等模型输入参数的灰色特性，使得以近似点值为输入得到的计算结果缺乏准确性依据和度量，该文提出的灰色数学模型，用区间数代替近似点值建立灰色数学模型，得出热应力在线计算值的灰色描述，可以更好地符合工程计算需要。文中针对模型应用的复杂程度，以汽轮机转子为对象，对单纯灰边界问题给出了简单的端点计算法及其依据；对复合灰边界灰物性问题建立了差分格式的数学模型，应用区间高斯迭代算法，结合模型结构特点推导了简易的基于内包含不等式的算法，并且给出两种算法的数值算例对比。     

自来水节能阀的设计

系统地论述了自来水节能阀的控制原理和特点 ,提出了设计框架并进行了理论分析和推导计算     

Advanced Coatings on Furnace Wall Tubes

Nickel-based self-fluxing alloy coating extends the service life of furnace wall tubes at waste incineration plants due to its excellent corrosion resistance and heat resistance. Fusing of such coatings by induction heating offers improved efficiency and reliability of products. Compared with conventional plasma, flame, and high-velocity oxy-fuel spraying thermal-sprayed coatings, induction-fused coatings provide a far stronger metallurgical bond at the interface, while minimizing the inclusion of pores. In addition, the tubes are less costly than those with welded coatings, and the process reduces the distortion of the products, facilitating easier final assembly. A successful experimental application of 11 units in a waste incinerator revealed virtually no corrosion on the exposed surfaces, and showed an improved water heating efficiency over that of the original tubes. Such units are now being employed in four incinerators in Taiwan, and continuing tests are showing great promise.     

大凌河流域典型水生植物微生物群落吸附特征试验分析

本文采用高通测序方法对大凌河流域五刺金鱼藻、格菱、狐尾藻、水蓼及芦苇5种水生植物不同季节的微生物群落进行试验分析,分析表明:藻类密度在沉水植物表层要高于浮叶植物表层,微生物群落在浮叶植物根部的结构与其表面存在明显差异。各水生植物的优势生物群落依次为变形菌、梭菌、柔膜菌、鞭脂杆菌、杆菌、疣微菌门,且各微生物群落在季节丰度上存在明显差异性。由此可见,水环境对生物群落的影响要高于植物类型。研究成果可为大凌河流域生态修复工程提供重要理论依据。     

Positive state‐bounding observer for positive interval continuous‐time systems with time delay

This paper is concerned with the problem of positive observer synthesis for positive systems with both interval parameter uncertainties and time delay. Conventional observers may no longer be applicable for such kind of systems due to the positivity constraint on the observers, and they only provide an estimate of the system state in an asymptotic way. A pair of positive observers with state‐bounding feature is proposed to estimate the state of positive systems at all times in this paper. A necessary and sufficient condition for the existence of desired observers is first established, and the observer matrices can be obtained easily through the solutions of a set of linear matrix inequalities (LMIs). Then, to reduce the error signal between the system state and its estimates, an iterative LMI algorithm is developed to compute the optimized state‐bounding observer matrices. Finally, a numerical example is presented to show the effectiveness and applicability of the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Analysis of nonlinear electrical circuits using bernstein polynomials

In electrical circuit analysis, it is often necessary to find the set of all direct current (d.c.) operating points (either voltages or currents) of nonlinear circuits. In general, these nonlinear equations are often represented as polynomial systems. In this paper, we address the problem of finding the solutions of nonlinear electrical circuits, which are modeled as systems of n polynomial equations contained in an n-dimensional box. Branch and Bound algorithms based on interval methods can give guaranteed enclosures for the solution. However, because of repeated evaluations of the function values, these methods tend to become slower. Branch and Bound algorithm based on Bernstein coefficients can be used to solve the systems of polynomial equations. This avoids the repeated evaluation of function values, but maintains more or less the same number of iterations as that of interval branch and bound methods. We propose an algorithm for obtaining the solution of polynomial systems, which includes a pruning step using Bernstein Krawczyk operator and a Bernstein Coefficient Contraction algorithm to obtain Bernstein coefficients of the new domain. We solved three circuit analysis problems using our proposed algorithm. We compared the performance of our proposed algorithm with INTLAB based solver and found that our proposed algorithm is more efficient and fast.     

光伏电站远程监控系统设计

本文主要论述分散式光伏电站远程监控系统的设计与实现。远程监控系统主要由基于B/S的三层体系结构主站、基于ARM的智能终端以及基于单片机的数据采集装置组成。数据采集装置主要采集光伏电站的电压电流等信息,通过RS232串口传给智能终端;智能终端分析处理采集的数据,通过GSM短信机制和主站通信,从而实现光伏电站的远程监控。     

高比例可再生能源渗透下多虚拟电厂多时间尺度协调优化调度

考虑可再生能源出力、电力负荷和电价等一系列不确定性因素,提出了高比例可再生能源渗透下的多虚拟电厂日内两阶段优化调度模型。该模型通过对多虚拟电厂中运行设备小时级时间尺度和分钟级时间尺度的协调优化,达到分级消除系统中随机和扰动因素的影响,实现高比例可再生能源的安全消纳。并且在多虚拟电厂优化调度模型中,借助Markowitz均值-方差理论,提出利润函数的风险刻画,准确描述不确定性的影响。最后,通过算例分析,说明所提出模型可有效降低决策风险和不确定性因素的影响。