基于PLC的袋式除尘器控制系统设计与实现

基于可编程控制器PLC的袋式除尘器控制系统设计包括硬件和软件2部分。硬件有PLC、信号处理单元、热电偶、差压变送器、压力传感器及开关电源;软件部分有PLC的控制和监控程序,以及基于VB和C++软件平台开发的PC机监控和数据采集程序。基于PLC的袋式除尘器控制系统能用于独立的除尘器设备,也能运用于大型燃煤电厂及大型生物质电厂和室内除尘器等烟气处理系统的现场总线控制,能够过滤污染气体,达到净化空气的目的,具有良好的应用前景和广泛的应用领域。     

经济危机和信贷扩张背景下的通货膨胀风险测度研究

基于货币长期中性的假设,建立通货膨胀风险测度模型,并将全球经济危机和中国信贷扩张作为冲击因素引入模型,研究发现在经济危机造成的破坏不再恶化的情况下,中国将可能从2010年下半年开始出现明显的通货膨胀压力;如果经济危机造成的破坏超出预期,则从2010年开始,CPI指数将重新回到大于零的区间,但考虑到货币供应量冲击对通货膨胀的影响具有相当的滞后性,因此中国2009年信贷扩张的效应可能在2～3年后才会完全显现出来。     

数字脉冲应答机的时延补偿方法

针对模拟体制脉冲应答机中声表面波延迟线的设计缺陷,运用基于FPGA的数字存 储转发技术,提出一种数字化高精度时延补偿方法,大大提高了脉冲应答机的时延转发精度 。 该脉冲应答机具有延迟时间易修改、转发精度高等特点,对实际工程应用具有借鉴价值。     

幅频算术对称无源带通滤波器的优化设计

为解决无源带通滤波器幅频算术对称问题,提出一种基于极点放置技术的优化设 计方法,即在网络综合法设计的滤波器电路基础上,将并臂电感换成串臂电感,在此电感上 并联电容增加衰减极点,并利用电路优化技术,使得幅频特性算术对称。实例结果表明,该 方法能够使滤波器幅频特性算术对称,而且带内波动小,电路结构简单,阶数少,插入损耗 低。     

The US Housing Market: Asset Pricing Forecasts Using Time Varying Coefficients

The US housing market has experienced significant cyclical volatility over the last twenty-five years due to major structural changes and economic fluctuations. In addition, the housing market is generally considered to be weak form inefficient. Houses are relatively illiquid, exceptionally heterogeneous, and are associated with large transactions costs. As such, past research has shown that it is possible to predict, at least partially, the time path of housing prices. The ability to predict housing prices is important such that investors can make better asset allocation decisions, including the pricing and underwriting of mortgages. Most of the prior studies examining the US housing market have employed constant coefficient approaches to forecast house price movements. However, this approach is not optimal as an examination of data reveals substantial sub-sample parameter instability. To account for the parameter instability, we employ alternative estimation methodologies where the estimated parameters are allowed to vary over time. The results provide strong empirical evidence in favor of utilizing the rolling Generalized Autoregressive Conditional Heteroskedastic (GARCH) Model and the Kalman Filter with an Autoregressive Presentation (KAR) for the parameters time variation. Lastly, we provide out-of-sample forecasts and demonstrate the precision of our approach.     

Dynamic Efficiency in the East European Emerging Markets

The paper re-investigates the efficiency of the East European emerging markets of the Czech Republic, Hungary, Poland and Russia analyzed by Rockinger and Urga (2000, 2001) based on the data from September, 1995 through December, 2004. We propose a first-order autoregressive (AR (1)) type time varying parameter model with a non-stochastic linear time trend including the random walk (RW) type model as a special case. The observed data rejects the RW type model for the AR (1) type one. The markets exhibit dynamic efficiency for all the four countries in the sense that the linear time trend approaches to zero over time. The empirical result for the Russian markets differs from that of Rockinger and Urga (2000). JEL Classifications: G14, G15     

Cusum Techniques for Technical Trading in Financial Markets

It is discovered that the CUSUM techniques often used in the manufacturing industry can be adapted to yield a trading strategy in the financial market. The familiar filter trading strategy in finance is found to be a particular case of CUSUM procedures. A more general form of the CUSUM techniques will yield new trading strategies which have intuitive appeals. Trading characteristics of such strategies will be investigated using CUSUM techniques.     

A Kalman filter formulation for noisy regional job data

A problem of great concern to regional economic forecasters is how to know the current local economic status given the delays and noise in provisional data. In this paper the structure of revisions to one of the most important regional data sets, local jobs by industry, is analyzed. A Kalman filter formulation is presented that can be used to improve the monthly estimates of jobs in local industries where large subsequent data revisions are most likely. Two data sets, one for the State of Virginia and one for the Louisville MSA, are used to illustrate the technique. The results, while not conclusive, suggest that the technique may be of practical importance in the monitoring and forecasting of employment activity in mining, construction and other industries for which provisional estimates are subject to the greatest later revision.     

基于CPLD的FIR滤波器的快速实现

介绍了用CPLD实现高精度高速度FIR数字滤波器的基本方法,可以方便地调整滤波器的阶数和系数,适合不同的应用。时序分析表明,该设计在系数量化数据宽度为20bit时可工作于40MHz以上的时钟频率。用设计软件对X-Ray取样信号进行功能仿真,并与Matlab仿真结果进行比较。结果表明该设计是可靠的,可以满足一些高精度实时系统如X-Ray数字谱仪的需求。     

加料方式对纳米氧化镍收率影响的研究

在常温下,以N iC l2.6H2O为原料,(NH4)2CO3为沉淀剂,采用液相沉淀法制备纳米N iO。在相同反应条件下采用顺加、逆加、并加三种加料方式,实验结果表明逆加方式得到产物的收率最高。