山区输配水管网沿线流量与节点流量的简化计算研究

目前全国范围内不断有农村饮水工程投入建设。其中,供水工程的管网布置与输水管管径的确定是输配水工程设计计算的两大课题。在管网与输水管的布置完成后,其管径确定得合理与否就成为影响输配水系统的投资与运行费用的主要因素。本文介绍沿线流量与节点流量计算方法,并结合典型山区农村供水工程输配水设计实例进行验证分析。     

基于GPS终端的实时路况信息采集方法研究

浮动车的实时路况信息采集存在采集内容复杂、信息不准确等问题.为此,提出一种基于GPS终端的实时路况信息采集方法.采用面向简化路网模型的采集方法,只考虑路段行程时间与路段中途停车时间,将GPS终端替代服务器负责采集内容和地图匹配.实验结果表明,与传统的基于服务器端采集方法相比,该方法能使采集内容更简单,采集信息更准确,可减轻服务器端的高负荷,便于采集信息的传输.     

基于字体的中文信息隐藏算法

为了将秘密信息嵌入到特定的载体之中,实现安全、高效的信息传输,以达到安全通信或版权保护等目的,针对中文文本设计了基于字体的信息隐藏算法.分析了文本信息隐藏的研究现状和存在的不足,根据不同的安全和嵌入率的需求,给出了3种对电子文本、打印文本、手写文本等皆适用的秘密信息嵌入算法,并且通过数学推导,对3种嵌入方式的嵌入率和嵌入效率等进行了分析比较.对算法的安全性进行了分析,并给出了增强安全性的手段.     

Simplified MMSE Detectors for Turbo Receiver in BICM MIMO Systems

In this article, two methods adopting simplified minimum mean square error (MMSE) filter with soft parallel interference cancellation (SPIC) are discussed for turbo receivers in bit interleaved coded modulation (BICM) multiple-input multiple-output (MIMO) systems. The proposed methods are utilized in the non-first iterative process of turbo receiver to suppress residual interference and noise. By modeling the components of residual interference after SPIC plus the noise as uncorrelated Gaussian random variables, the matrix inverse for weighting vector of conventional MMSE becomes unnecessary. Thus the complexity can be greatly reduced with only slight performance deterioration. By introducing optimal ordering to SPIC, performance gap between simplified MMSE and conventional MMSE further narrows. Monte Carlo simulation results confirm that the proposed algorithms can achieve almost the same performance as the conventional MMSE SPIC in various MIMO configurations, but with much lower computational complexity.     

Design of a simplified adaptive fuzzy backstepping control for uncertain discrete-time nonlinear systems

This paper presents a simplified adaptive fuzzy backstepping control for uncertain discrete-time nonlinear systems. It is assumed that the systems are described by a discrete-time equation with nonlinear uncertainties to be viewed as the modelling errors and the unknown external disturbances, and the states are observed with measurement noises. To design the simplified adaptive fuzzy backstepping control, the modelling errors are approximated by using the fuzzy inference approach based on the extended single-input rule modules, and the estimates for the unmeasurable states and the adjustable parameters are derived by using the weighted and its simplified weighted least squares estimators. It is proved that the states are ultimately bounded, and the estimation errors remain in the vicinity of zero. The effectiveness of the proposed approach is indicated through the simulation experiment of a simple numerical system.     

Adaptive fuzzy dynamic surface control for a class of stochastic MIMO discrete-time nonlinear pure-feedback systems with full state constraints

This paper presents the design of an adaptive fuzzy dynamic surface control for a class of stochastic MIMO discrete-time nonlinear pure-feedback systems with full state constraints using a set of noisy measurements. The design approach is described as follows. The nonlinear uncertainty is approximated by using the fuzzy logic system at the first stage, secondly the proposed adaptive fuzzy dynamic surface control is designed based on a new saturation function for full state constraints, thirdly the number of the adjustable parameters is reduced by using the simplified extended single input rule modules, and finally the simplified weighted least squares estimator is in a simplified structure designed to take the estimates for the un-measurable states and the adjustable parameters. The simulation provides that the proposed approach is effective for the improvement of the system performance.     

在sql中实现获取汉字拼音简码

介绍了在sql server中文利用SQL SERVER的排序规则,获取汉字拼音简码的方法.利用汉字的拼音简码查找记录,减少了操作时的汉字录入量,加快了操作速度,增强了软件的易用性.该方法在管理信息系统中得到了应用,效果很好.     

京杭运河杭州段水质模型研究

以京杭运河杭州段为对象,研究主要水污染超标因子氨氮的浓度预测方法.选取2007年6月2～10日运河实测水质变化过程,根据干流各节点的初始浓度和各支流的浓度,结合水位流量自动监测数据,分别用简化水库模型和有限差分法预测运河干流各节点的氨氮浓度,并与实测值进行比较分析.简化水库模型和有限差分法应用于该次水体氨氮浓度计算中,两者的误差均在5%以内,对运河水质预测均有一定的代表性.     

黏土层中深基坑挡土墙最大变形量简易评估法

利用数值分析，研究影响黏土层中基坑挡土墙最大变形量的参数，根据参数研究的结果，利用复回归分析，给出挡土墙最大变形量的简易评估法。然后利用简易评估法，预测4个台北基坑案例的连续墙最大变形量，并与现场监测结果进行比较。结果显示：预测的最大变形量在0.85～1.15倍监测值范围内。因此，本文给出的简易评估法，可为初步预测、设计及最后检核设计成果提供参考。     

等截面柱形直肋-维修正传热(近似解)方程及肋传热量的新的简化计算

针对一维经典肋传热方程及近似解的局限性，推出了等截面柱形直肋的一维修正肋传热方程及修正近似解。进一步针对工程中肋端传热时热量的简化计算法提出了一种新的更为精确的修正简化计算公式。数值比较结果表明：提出的公式不仅具有原经典公式相同形式及简洁性，而且使得肋根部热流率及各截面平均温度的计算精度有了显著的提高，并将公式的应用范围扩大至较大Bi数，这为肋片的工程设计优化和应用提供了更为准确而直观的求解方法。