小型无人机导航系统的探索与研究

针对执行特定海域巡航的小型无人机,提出了GPS/INS组合导航系统的解决方案。首先介绍导航系统的算法和原理,根据任务需求,给出硬件构成及软件核心程序流程,通过仿真,证明在组合系统中采取PID控制以及卡尔曼滤波算法大大提高了导航的精度。     

MIMO系统中基于卡尔曼滤波的信道预测算法研究

多输入多输出(MIMO)技术是LTE系统中的关键技术之一,能够在不增加带宽的情况下成倍地提高了通信系统的容量和频谱利用率。本文提出了一种多用户MIMO下行链路中基于卡尔曼滤波的信道预测算法。在实际传输时,发射端根据接收端反馈回来的信道信息预测出下一时刻的下行信道信息,仿真结果验证了所提方法的有效性。     

一种基于LSB的改进信息隐藏算法及实现

传统的LSB算法是将私密信息以二进制的形式嵌入到载体像素值的最低有效位,这样对图像的质量负面影响可以降到最小。本文提出了一种将过滤技术与LSB算法相结合的信息隐藏算法。利用过滤技术增强图片质量,利用LSB算法进行私密信息的嵌入。改进型的LSB算法比原算法具有更高信息存储量以及更高信息安全性等优点。     

An explanation for the price puzzle: Asymmetric information and expectation dynamics

Using theoretical and empirical analyses, this paper shows that the expectation dynamics induced by information asymmetry between the Central Bank (CB) and the public can cause the price puzzle. The signalling and learning dynamics between the CB and a representative private-sector agent under asymmetric information is investigated. Inflation positively reacts to contractionary monetary policy because the change in the interest rate is perceived as a signal of the CB’s private information about higher future inflation and output by the public. The empirical section of the paper validates this theoretical argument using a VAR specification about the US economy. Besides providing an explanation for the price puzzle, the results of this paper has practical implications about transparency and monetary policy. The theoretical and empirical findings indicate that asymmetric information causes significant frictions in the transmission mechanism of monetary policy. These frictions induce short-run undesired effects like increase in expected inflation and actual inflation as a response to contractionary monetary policy which is identified as “the price puzzle”.     

浅层地下水监测井快速成井工艺试验

地下水监测井是进行地下水各项参数监测的重要途径。随着监测技术的发展,对于成井井管直径的要求越来越小,但是受常规成井工艺的制约。为保障填砾止水工序顺利实施,井管与井壁之间间隙需求较大,使得监测井井径依然较大,而且常规成井工艺工序烦琐、效率低,对地下水填砾止水分层的精细化、准确度较差。依据地下水监测井的目的和特点,通过试验与分析对常规成井工艺进行优化,采用预制滤水管体和止水管体替代填入砾料和止水材料的流程,简化成井工艺,同时满足小口径成井需求,可有效提高钻进效率,降低施工成本,精细准确地进行滤水段和止水段分层,并分析了优化后成井工艺的可靠性,为优质高效地建设浅层地下水监测井提供技术支撑。     

微波梳状线带通滤波器脉冲功能容量的研究

本文以迅速崛起的新兴市场为研究范围,以跨国公司在新兴市场的营销渠道策略的理论和实践的最新发展为研究对象,对跨国公司在新兴市场的营销渠道策略的创新进行分析,以丰富营销渠道的理论和实践.     

终端短路圆杆交指带通滤波器的设计

介绍了一种终端短路式圆杆交指带通滤波器的设计方法。根据交指滤波器的准确设计理论获得的圆杆自电容和互电容，结合图表得到了滤波器的最初尺寸，并结合微波电路仿真软件对其进行了优化、仿真。仿真结果和实际测试的结果比较一致。证明了设计方法的可行性。     

一种混沌密码序列的产生及其改进

尝试用数字滤波器产生混沌密码序列 ,针对已有算法和它的一些改进算法存在内部状态间具有较强相关性的问题 ,提出了一种新的改进方法 ,通过合理选择系数 ,产生了效果较好的混沌密码序列     

基于DSP技术的RFID读写器设计

论述了基于DSP技术的RFID读写器设计方法。在描述RFID系统组成的基础上，给出了读写器的软硬件设计流程。重点阐述了DSP对接收信号的软件处理以及反冲撞功能的实现方法。该读写器已应用于开放式门禁系统中，实际应用结果表明其性能良好。     

Are Hodrick-Prescott `forecasts' rational?

We evaluate the usefulness of the Hodrick-Prescott (HP) filter as a proxy for rational expectations, using long runs of annual US inflation data. Our conclusion is that while the HP series are not fully rational in the sense of Muth (1961), they do generally meet the criterion of `weak rationality' recently proposed by Grant and Thomas (1999). They are also rational proxy predictors of direction for, following Merton (1981), agents would not change their prior in the opposite direction to these `forecasts'. However, smoother HP `forecasts' are more prone to inefficiency and less useful predictors of direction. First Version Received: May 2000/Final Version Received: May 2001