基于卡尔曼滤波和增量PID的双向DC-DC变换器

利用单片机控制锂电池的充放电以及升压和降压拓扑电路构成高效双向DC-DC变换器电路以提高能源利用率。单片机通过控制加法器和运算放大电路反馈端数字电位器阻值以实现实现输出电流步进可调,通过PID算法控制降压电路的反馈电压微调输出电压值提高输出电压稳定性,采用电流传感器和电压衰减电路,并结合单片机和卡尔曼滤波算法提高实时测量系统状态电压、电流测量精度。     

小波降噪对地震加速度误差的实例分析

小波降噪是近年来兴起的一种非常有发展前景的降噪方法。在图像边缘提取、语音处理中有广泛的应用。文章介绍小波降噪模型的基本理论,通过对地震加速度传感器测量数据进行仿真分析和误差校正,对加速度检测数据提出了校正结果,得到符合运动事实的规律曲线,在对地震加速度的采集和整理上有很大应用,得出小波降噪模型的可靠性。     

曲柄滑块机构的运动特性分析

这里在曲柄滑块运动简图的基础上,建立数学模型进行运动分析,并应用Matlab所具有的强大数值计算和仿真功能,绘出其位移、速度、加速度和角速度曲线图,提高了设计效率的机构精度。     

关于测量数据校正技术的研究

从1961年起,测量数据校正技术就开始应用于化工过程,经过不断地发展和完善,该技术在越来越多的领域得到应用。测量数据校正技术的目标是改善工艺数据的一致性和准确性,为生活和生产提供安全保障。     

基于AD7705的高精度pH值数据采集系统的设计

在糖厂澄清工段pH值控制中,pH值的精确采集影响石灰乳、二氧化硫的加入量,为了提高pH值传感器输出信号的采集精度,本系统采用前置放大,再滤除杂波,然后放大到相应倍数,最后通过AD7705进行模数转换,得到精确稳定的数字信号。     

振动检测器的研究与设计

本文介绍了一种监测旋转设备振动强度的设备,详细介绍了有源积分电路、带通滤波器电路以及单片机控制电路的工作原理,阐述了磁电式传感器的工作机理,设计的带通滤波器电路有效地滤除了传感器输出信号的噪声。在实验环境下对系统进行了测试,实验表明,该振动监视系统具有较高的测量精度。     

激光甲烷传感器检测误差温压补偿修正模型分析

温度对CH₄气体吸收谱线具有显著影响,低温下吸收谱线变窄,高温下吸收谱线变宽。压力则导致了测量浓度的降低。为了提高测量精度,根据温度对吸收率和分子间距离的影响进行补偿。文章提出的基于BP神经网络的温压补偿修正模型经过实验验证,能够改善激光甲烷传感器的测量精度。通过修正温度和压力对传感器测量结果的影响,可以准确获得甲烷浓度的测量值。     

虚拟仪器技术在传感器与检测实训系统中的应用

构建了基于虚拟仪器技术的传感器与检测实训系统,利用测力传感器、测速传感器及加速度传感器测量不同的物理量,使用USB-5935数据采集卡完成信号采集,利用编程语言Lab Windows/CVI进行信号的数据采集与处理。此测试方法减少了复杂的硬件电路,简化了测试系统,提高了测试系统的测量精度和可靠性,并可根据实际教学需要拓展测试系统全面提高了测试系统功能,提高了工作效率。     

试论光纤陀螺技术的发展及应用

光纤陀螺是现阶段最新的角速度传感器,与上一代的激光陀螺相比,其优势明显,构件较少、体积小、重量轻、造价便宜,在承受较大的温度变化后仍能保持较高的精度,因此在航空航天、军事以及工程等各个领域得到了广泛的应用。文章分析了光纤陀螺的优点,论述了光纤陀螺技术的发展现状,介绍了光纤陀螺技术的应用。     

杂波对毫米波RCS海上测量定标的影响分析

雷达目标回波包含目标的材料性质、几何形状、运动规律等诸多特性。测量目标RCS时,对定标体的计算是十分重要的,直接影响雷达目标回波的最终分析。本文根据三毫米频段的特点,分析了定标过程中各种杂波对测量精度的影响。有助于在工程中尽可能减小杂波对测量的影响．更好的完成工程需要。     

用于车载立靶信号处理的数字滤波器设计

在对弹丸速度的测试中,传统的接触式测量方法已逐渐被非接触式测量方法所替代,在非接触式测量方法中主要是利用光幕靶和天幕靶对弹丸速度、飞行姿态、立靶密集度、跳角、飞行时间和气象参数等进行测量。天幕靶和光幕靶是以光电技术为基础,进行弹速和弹丸飞行偏、倾角的测量以及着靶位置的非接触测量。近几年国内研制的非接触立靶测试系统均在仪器不存在运动的状态下工作,若将立靶系统放在以一定的速度运动的活动车上,由于震动等原因,立靶输出较大的噪声信号而无法工作。本文就是针对震动噪声这一问题,利用MATLAB对车载立靶输出的弹形信号和噪声信号进行频谱分析,并在分析结果的基础上,设计数字滤波器,实现对震动噪声的有效抑制,解决车载立靶的震动噪声问题。     

Selecting Adaptive Survey Design Strata with Partial R‐indicators

Recent survey literature shows an increasing interest in survey designs that adapt data collection to characteristics of the survey target population. Given a specified quality objective function, the designs attempt to find an optimal balance between quality and costs. Finding the optimal balance may not be straightforward as corresponding optimisation problems are often highly non‐linear and non‐convex. In this paper, we discuss how to choose strata in such designs and how to allocate these strata in a sequential design with two phases. We use partial R‐indicators to build profiles of the data units where more or less attention is required in the data collection. In allocating cases, we look at two extremes: surveys that are run only once, or infrequent, and surveys that are run continuously. We demonstrate the impact of the sample size in a simulation study and provide an application to a real survey, the Dutch Crime Victimisation Survey.     

Multiple Objective Approach as an Alternative to Radial Projection in DEA

Radial projection is a standard technique applied in data envelopment analysis (DEA) to calculate efficiency scores for input and/or output variables. In this paper, we have studied the appropriateness of radial projection for target setting. We have created a situation where the decision making units (DMUs) are free to choose their own target values on the efficient frontier and then compared the results to those of radial projection. In practice, target values are primarily used for future goal attainment; hence, not only preferences but also, and on the whole, change in time frame, affect the choice of target values. Based on that, we conducted an empirical experiment with an aim to study how the DMUs choose their most preferred target values on the efficient frontier. The subjects, who all were students of the Helsinki School of Economics, were given the freedom to explore their personalized efficient frontiers by using a multiple objective linear programming (MOLP) approach. To study various and relevant scenarios, the personalized efficient frontiers for all students were constructed in such a way that the current position of each student in relation to the frontier made him/her inefficient, efficient, or super-efficient. The results show that the use of radial projection for target setting is too restrictive.     

Modelling oil price expectations: Evidence from survey data

Using Consensus Forecast survey data on WTI oil price expectations for 3- and 12-month horizons over the period November 1989 to December 2008, we find that the rational expectation hypothesis is rejected and that none of the traditional extrapolative, regressive and adaptive processes fits the data by itself. We suggest a mixed expectation model defined as a linear combination of these traditional processes, which we interpret as the aggregation of individual mixing behavior and of heterogenous groups of agents using these simple processes. This approach is consistent with the economically rational expectations theory. We show that the target oil price included in the regressive component of this model depends on the long-run marginal cost of crude oil production and on short term macroeconomic fundamentals whose effects are subject to structural changes. For the two horizons, estimation results provide evidence for our mixed expectation model incorporating this break-dependent target price.     

Targets and Resources: A Screening Perspective

To secure funding for a project, an agent (informed about the project's type) announces a target output. The principal provides more generous resources for high targets but makes compensation tied to performance relative to the projection. The incentive mechanism is geared towards screening project/agent types for resource disbursement at the ex‐ante stage and motivating appropriate efforts at the interim stage. These dual objectives are embedded in an optimal share contract solution: a pair of startup funds and output share between the principal and agent. The target mechanism's performance is then assessed with respect to implementation of the optimal share contract solution. The focus is on linear contracts for their applicability and practical relevance. Copyright © 2016 John Wiley & Sons, Ltd.     

The zero lower bound,the dual mandate,and unconventional dynamics

This paper examines monetary policy when it is constrained by the zero lower bound (ZLB) on the nominal interest rate. Our analysis uses a nonlinear New Keynesian model with technology and discount factor shocks. Specifically, we investigate why technology shocks may have unconventional effects at the ZLB, what factors affect the likelihood of hitting the ZLB, and the implications of alternative monetary policy rules. We initially focus on a New Keynesian model without capital (Model 1) and then study that model with capital (Model 2). The advantage of including capital is that it introduces another mechanism for intertemporal substitution that strengthens the expectational effects of the ZLB. Four main findings emerge: (1) In Model 1, the choice of output target in the Taylor rule may reverse the effects of technology shocks when the ZLB binds; (2) When the central bank targets steady-state output in Model 2, a positive technology shock at the ZLB leads to more pronounced unconventional dynamics than in Model 1; (3) The presence of capital changes the qualitative effects of demand shocks and alters the impact of a monetary policy rule that emphasizes output stability; and (4) In Model 1, the constrained linear solution is a decent approximation of the nonlinear solution, but meaningful differences exist between the solutions in Model 2.     

机电控制中霍尔传感器测量力的实现

为了克服传统应变片式力传感器结构复杂、应变片之间平衡困难等缺点,将霍尔元件与弹性元件组合使用。文章利用霍尔元件能进行微小位移测量的优点,用霍尔元件代替应变片测量力传感器弹性体的形变,从而测量出力的大小,这种霍尔力传感器具有结构简单、精度高、线性好的优点,可作为便携式测量仪器的传感器使用。     

衡量城市化与工业化比较水平的新指标研究

本文通过Granger因果关系检验和回归分析,分别确定了城市化和工业化的特征指标,即建筑业产值和机械工业产值。并以此构建衡量城市化与工业化比较水平的指标,即建筑业产值与机械工业产值的比值。进而使用该指标对中国及其他部分国家的现状做横向的比较,发现中国城市化相对于工业化的水平较其他国家滞后。同时对中国纵向的发展分析发现,城市化与工业化比较水平波动较大,受到诸多因素的影响。     

GPS控制网设计

根据需要,拟在宜昌以下河段新建首级GPS控制点40个,同时兼顾可利用的旧点及邻近国家高等级点联入新网。Ⅱ级控制在首级控制网下加密,兼顾常规测量方法需要,利用原有可利用控制点联测转换,计350点,高程控制在长江中下游建三等水准420点。建立独立的局部首级控制系统。一期工程建成后,将建立一套航道测量GPS控制网点,同时检核、提高原有可利用控制点的精度,为航道开发、建设提供高精度的、使用方便的控制资料,适应航道测量工作需要。