小信号反馈放大器的无环信号流图分析法

本文揭示了一种避免解联立方程组而直接分析小信号反馈放大器的方法,即用传输矩阵对双端口网络进行分析.这样一来,一个小信号反馈放大器就可用不含反馈环的级联信号流图表示,以得到一些具体结果.     

修正FTF算法用于高速数传快衰落信道自适应均衡的研究

短波高速数传是当前通信领域研究的一个重要方面,克服这类信道快衰落时变特性给数传带来的障碍是研究的中心课题.近些年提出和探讨的最小平方自适应均衡新技术,人们认为是解决这一问题的有效途径,普遍为人关注.本文对作者已提出的计算复杂度低、稳定性良好的修正 FTF 自适应均衡算法作了进一步研究.考查了其硬件实现方面的问题并模拟分析了均衡性能,初值选取,最佳级数和启动时训练与否的影响等,得出了许多有益的结论.这些分析与讨论对于硬件实现是十分必要的.     

CCD图像采集过程中的实时误差校正

根据引入误差的设备不同，分别介绍了两种误差实时校正方法——信号采集部分的实时误差校正和输出设备的实时误差预校正的原理和实现方法．两种误差实时校正方法具有简单、实现方便、速度快和精度高等特点，在采集原始图像的同时，既可以存储系统误差校正后的图像文件，又可以在监视屏实时显示逼真的原因像．     

采用监督信号的供应链内部知识转移激励机制

目前,一些与激励机制有关的研究开始在供应链内部知识转移中展开,但通常仅考虑对知识供给方的激励而忽略了对知识供给方的监督,致使激励效果受到限制。为解决此问题,采用数学建模与计算机仿真分析方法,通过引入监督信号,在供应链内部成员间知识转移基本激励模型的基础上,分别建立供应链上下级和同级成员间知识转移激励模型。研究发现,采用监督信号后,无论是上下级还是同级成员之间,供应链内部知识转移的收益水平和转移效率均得到了提升,但相比同级成员,供应链上下级成员间知识转移的收益水平和转移效率更高,收益更大。研究成果能为供应链企业有效开展知识转移活动和提升供应链竞争能力提供实践指导。     

产品质量信号与企业融资成本的相关性研究

以“中国企业-雇员匹配调查”（CEES）数据库中2014年的数据为样本,利用多元线性回归方法,研究我国制造业企业的产品质量信号,是否与其融资成本存在相关关系。研究以通过问卷调查所获得的企业融资成本数据作为因变量,以企业通过质量管理体系认证、是否获得国际市场准入和自有品牌数量作为自变量,来反映企业的产品质量信号传递状态。研究发现,在控制抵押物规模、杠杆率、固定资产周转率、董事会治理结构等因素的条件下,品牌信号与企业融资成本间存在显著的正相关关系,原因在于产品质量信号传递的低效,以及信号传递机制的失灵。     

Economic-statistical design of simple linear profiles with variable sampling interval

Control charts are statistical tools to monitor a process or a product. However, some processes cannot be controlled by monitoring a characteristic; instead, they need to be monitored using profiles. Economic-statistical design of profile monitoring means determining the parameters of a profile monitoring scheme such that total costs are minimized while statistical measures maintain proper values. While varying sampling interval usually increases the effectiveness of profile monitoring, economic-statistical design of variable sampling interval (VSI) profile monitoring is investigated in this paper. An extended Lorenzen–Vance function is used for modeling total costs in VSI model where the average time to signal is employed for depicting the statistical measure of the obtained profile monitoring scheme. Two sampling intervals; number of set points and the parameters of control charts that are used in profile monitoring are the variables that are obtained thorough the economic-statistical model. A genetic algorithm is employed to optimize the model and an experimental design approach is used for tuning its parameters. Sensitivity analysis and numerical results indicate satisfactory performance for the proposed model.     

Correlation analysis-based error compensation recursive least-square identification method for the Hammerstein model

In this paper, the correlation analysis based error compensation recursive least-square (RLS) identification method is proposed for the Hammerstein model. Firstly, the covariance matrix between input and output data points of the Hammerstein model is derived by using separable signal to realize that the unmeasurable internal variable is replaced by the covariance matrix of input. Thus, the correlation analysis method can be accordingly used to estimate parameters of the linear part, which results in the identification problem of the nonlinear part separated from the linear part. In addition, a correction term is added to least-square estimation to compensate error caused by output noise, further the error compensation-based RLS method is obtained for the observed data from the Hammerstein model. As a result, the least-square identification method, which generates error in the presence of noise distribution, can be compensated. Finally, simulation experiments are conducted to illustrate the performance of the proposed identification method.     

食品安全“监管困局”、信号扭曲与制度安排

在既有研究提出的食品安全“监管困局”现象基础上，通过仿真建模及分析进一步解剖该困局的动态形成过程，构建食品市场中生产者、消费者和监管者构成的两期博弈模型，剖析食品安全“监管困局”的内在形成机理． 研究发现: 1) 加大监管力度形成的违规揭露信息会影响到消费者的支付预期，当违规揭露水平超过消费者心理承受时会降低消费者的支付水平，进而影响食品行业平均收益，导致生产经营者的超额违规收益迅速增大，反过来又增强了生产经营者的违规动机，是为食品安全“监管困局”的动态形成过程; 2) 食品安全“监管困局”在于监管者与企业、监管者与消费者两种信息结构使监管力度的信号被扭曲所致，即政府监管力度对消费者形成信号扭曲，消费者无法通过市场价格实现质量信号分离，从而降低支付水平而影响行业平均收益． 本文由此提出针对性的制度安排．     

Economic and economic-statistical designs of the T2 control charts with SVSSI sampling scheme

Recent studies have shown that the adaptive T² chart with two different sampling interval and three sample sizes (SVSSI) shows a good performance in detecting small to large shifts in the process mean. This paper investigates the economic and economic statistical designs of the SVSSI T² charts. We use the Markov chain approach to developing the cost model proposed by Costa and Rahim (Journal of applied statistics 2001; 28: 875–885). A genetic algorithm approach is used to find the optimal solutions. Using numerical examples, we illustrate the performance of the proposed model and compare the statistical, economic, and economic statistical designs of the SVSSI T² chart with respect to the economic and statistical criteria. Furthermore, we compare the performance of the SVSSI T² chart with the other T² control schemes.     

石油钻杆内爬行器信号处理系统的设计

基于漏磁检测原理的钻杆内爬行器，可在石油钻杆内部运动．并对分布于钻杆内壁的缺陷进行检测。由于石油钻井用钻杆的外径通常都较小（通常在60．3～88．9mm），要求内爬行器的信号处理系统体积小、功耗低、具有数据记录功能、自带供电模块。设计了石油钻杆用漏磁信号处理系统，包括了一组信号放大电路、信号处理模块、电源模块、数据存储模块，并设计了相应的软件，实现了对漏磁信号的分析和记录，系统已在相关企业获得应用，取得良好效果，检测信噪比不低于10dB，对人工刻制的缺陷检出率达到100％。