基于振筒式压力传感器的某型检测系统设计

针对飞行器全静压系统的检测需求,设计实现了以80C552单片机为控制核心、基于振筒式压力传感器的自动检测系统,论述了系统的总体构成,重点设计了提高振筒式传感器测量准确度配套电路和测量显示组件.系统的实现提高了飞行器全静压系统的检测自动化程度,具有检测速度快、准确度高、判读直观、可靠性高和操作简单的特点,在实际测试中运行良好,性能稳定.     

Bayesian estimation based on vague lifetime data

In Classical Bayesian approach, estimation of lifetime data usually is dealing with precise information. However, in real world, some informations about an underlying system might be imprecise and represented in the form of vague quantities. In these situations, we need to generalize classical methods to vague environment for studying and analyzing the systems of interest. In this paper, we propose the Bayesian estimation of failure rate and mean time to failure based on vague set theory in the case of complete and censored data sets. To employ the Bayesian approach, model parameters are assumed to be vague random variables with vague prior distributions. This approach will be used to induce the vague Bayes estimate of failure rate and mean time to failure by introducing and applying a theorem called “Resolution Identity” for vague sets. In order to evaluate the membership degrees of vague Bayesian estimate for these quantities, a computational procedure is investigated. In the proposed method, the original problem is transformed into a nonlinear programming problem which is then divided into eight subproblems to simplifying computations.     

基于预测模型的轨迹数据压缩方法

针对目前路网环境下海量轨迹数据压缩效率低下的问题,提出了一种基于预测模型的轨迹数据压缩方法（CTPM）。通过将轨迹数据的时间信息和空间信息分别进行压缩,使得压缩后的轨迹数据在空间维度上无损,并且在时间维度上误差有界,以此提高压缩效率。在空间方面,首先利用部分匹配预测（PPM）算法通过轨迹已经行驶的部分路段对其下一时刻可能的位置进行预测;然后通过删除预测成功的路段来减少轨迹数据的存储代价。在时间方面,首先利用轨迹通行状况具有周期性的特点,构建了不同时间区间的通行速度统计模型,来预测移动对象进入下一路段所需要的时间;然后删除预测时间误差小于给定阈值的路段数据来进行压缩处理。实验结果显示,与已有的基于路网的并行轨迹压缩（PRESS）算法相比,CTPM的空间压缩比和时间压缩比平均分别提高了43%和1.5%,同时时间压缩误差减小了9.5%。实验结果表明所提算法在提高压缩比的同时有效地降低了压缩时间和压缩误差。     

非对称数据率网络下的无阻塞连接算法

基于稳定网的数据流连接算法已有很多研究成果,但在实际应用中,还需要处理不同速率网络下的查询连接,这使得目前流行的基于稳定数据流且内存分配固定环境下的连接算法难以适用。介绍了一种在非对称数据率网络下的无阻塞排序归并连接算法SMA。SMA算法的连接运算分为两阶段:join during run creation和join during merge,第一阶段可用于网络无阻塞情况下通过内存刷新策略来生成头批连接结果,第二阶段用于数据源受阻时借助外存驻留数据继续生成查询连接结果,从而保证了连接结果产生的无阻塞性。试验证明,SMA对等值和空间连接效率很高。     

Mutual information of cylinder pressure and combustion phase estimation in spark ignition engines

For the study of internal combustion engines, combustion control is an important method to achieve high efficiency and low emissions. Currently, in-cylinder pressure sensor-based closed-loop control strategies have become the preferred solution. However, their productional application in automotive industries is limited due to the cost of intensive pressure acquisition for a whole cycle and the calculation load of combustion phase indicators. This paper proposes a method of combustion phase estimation for spark ignition (SI) engines. In this method, the combustion phase is estimated only based on pressure measurements at several crank angles. Information entropy and mutual information are introduced to analyze the feasibility and accuracy of the combustion phase estimation, which shows that the pressure measurements at selected points contain most of the information for the estimation. As a result, only pressure measurements at 3 points and ELM estimation models are required to obtain the combustion phase, instead of intensive data acquisition and calculation.     

面向城市道路交通状态估计的数据融合研究

实时道路交通状态估计是ATMS和ATIS的重要内容。布设于城市道路网络中的各类检测器提供了丰富实时的动态信息。针对目前我国各检测器间相互独立形成信息孤岛、数据参数多样、结构迥异、采样周期和精度不一等现状,采用贝叶斯估计、模糊逻辑等数据融合方法建立多源异构交通信息三层次融合体系,得到精度更高、可靠性更强的交通信息。实例证明,数据融合适用于城市道路交通状态估计。     

基于自相关的数据延拓式频率估计方法

为提高自相关法在非整周期采样情况下的频率估计精度,提出一种基于自相关的数据延拓式频率估计方法。通过分析自相关法频率估计存在误差的根本原因,得出抑制频率估计误差的方法:对采样信号频率进行预估计;对自相关信号长度是否整周期进行判断,并进行数据延拓使自相关信号长度恰好或者近似为整周期;对延拓后信号进行频率估计。通过仿真实验表明:提出的方法不受信号非整周期采样的影响,有效地提高了频率估计精度。     

Accident analysis of gas cylinder handling work based on occupational injuries data

This study is concerned with the characteristics of occupational injuries and sick leave for gas cylinder handling workers. Possible incidents and sick leave have been identified and analyzed for 223 occupational accidents in the gas cylinder handling work. Management level of accidents for prioritizing prevention measures is induced for the combination of accident agencies, types, and gas cylinder handling work processes. Accidents occurring during the specific gas cylinder handling work process showed different characteristics, depending on the type and agency of the accident. Most critical accidents that require corrective actions for prevention were slips and trips caused by floors, walkways, steps, or ground surfaces and overexertion and bodily reaction and posture caused by gas cylinder in the manual delivery of heavy cylinders process. Also, fall to lower level caused by floors, walkways, steps, or ground surfaces in the loading to and unloading from vehicles process and struck by or against caused by fixtures in the manual delivery of heavy cylinders process were also ranked high. The findings of this study can be used to develop more effective accident prevention policies to reduce occupational accidents in gas cylinder handling works.     

汽油机非线性卡尔曼滤波暂态进气量估计及空燃比控制

暂态工况下缸进气量的准确估计是提高发动机空燃比控制精度的有效措施之一,为此本文提出一种基于无迹卡尔曼滤波的暂态缸进气量估计算法,并利用估计的缸进气量设计了一种前馈-反馈空燃比控制器.MATLAB环境下的仿真实验给出了所提出的算法与现有进气量估计算法的比较,同时基于暂态气量估计的空燃比控制仿真实验验证了估计的有效性.论文与现有成果的区别在于:一是暂态进气量估计模型不仅包含了歧管压力动态还考虑了曲轴角速度动态,并采用了基于非线性辨识的均值模型;二是考虑了泵气波动的影响,采用了移动平均值法的数字滤波器对泵气波动进行滤波;三是采用无迹卡尔曼滤波算法对歧管压力和曲轴角速度进行估计.     

基于线性化技术的渗透压摩尔浓度测量系统

在冰点下降原理基础上,研究了渗透压摩尔浓度测量系统测量过程和参数设置问题。应用100μA恒流源供电方式法和二阶范数最小二乘法曲线拟合算法相结合,提出了NTC热敏电阻器线性化新方法,建立了NTC热敏电阻器的Matlab修正模型,实现了NTC热敏电阻器线性化处理。在此基础上,采用高分辨率A/D进行模拟信号转换,完成了渗透压摩尔浓度测量系统的设计。经实验验证,测量精度为±1 mmol/kg(≤500 mmol/kg)或RSD≤±0.2%(>500 mmol/kg)。     

基于多速率传感器数据融合技术的最小二乘估计

将多速率传感器数据融合技术与传统最小二乘估计方法相结合,可以得到一种基于多速率传感器数据融合技术的最小二乘估计新方法。它通过有效地融合各个传感器的观测数据,最终获得了基于全局测量信息的在极小化估计误差方差的迹的准则下最优的无偏参数估计结果。针对具体应用实例,计算机仿真不仅说明了这种方法的实用性,而且进一步验证了其有效性。     

基于过程数据的空分系统参数估计

根据空分系统模型特点确定模拟计算中待估计参数,包含热力学参数以及设备参数。文献中通常采用常规浓度的实验气液平衡数据回归热力学参数,由于实验浓度达不到高纯度范围,热力学参数用于高纯度体系模拟时误差较大,故采用过程数据估计。考虑到待估参数较多,提出了通过分析参数全局灵敏度来判断关键参数,以减小参数估计的规模,估计参数由原来的10个减少到2个关键参数。基于过程数据采用最小二乘法对关键参数进行参数估计。将优化后的关键参数值应用于模拟计算,计算结果与5个实际工况测量值进行对比,可以看出模拟结果与实际工况吻合较好;将优化热力学参数代入热力学方程进行相平衡计算,并与实验气液平衡数据以及未优化的参数计算的结果进行比较,优化后参数的计算结果更加逼近于实验相平衡数据。     

The polytropic volume method to detect engine events based on the measured cylinder pressure

Internal combustion engines deliver work using an intermittent thermodynamic process. For control and diagnosis purposes, it is useful to detect key events relative to the crank angle position. A new method to detect the intake valve closing (IVC), start of combustion (SOC), end of combustion (EOC) or exhaust valve opening (EVO), using the measured cylinder pressure as input, is described. The method is based on the observation that the compression and expansion processes are of polytropic nature. It is shown that the events can be detected by detecting the points where the real and the polytropic volume diverge.     

Simple adaptive air-fuel ratio control of a port injection SI engine with a cylinder pressure sensor

The problem of air-fuel ratio(AFR) control of the port injection spark ignition(SI) engine is still of considerable importance because of stringent demands on emission control. In this paper, the static AFR calculation model based on in-cylinder pressure data and on the adaptive AFR control strategy is presented. The model utilises the intake manifold pressure, engine speed, total heat release, and the rapid burn angle, as input variables for the AFR computation. The combustion parameters, total heat release,and rapid burn angle, are calculated from in-cylinder pressure data. This proposed AFR model can be applied to the virtual lambda sensor for the feedback control system. In practical applications, simple adaptive control(SAC) is applied in conjunction with the AFR model for port-injected fuel control. The experimental results show that the proposed model can estimate the AFR, and the accuracy of the estimated value is applicable to the feedback control system. Additionally, the adaptive controller with the AFR model can be applied to regulate the AFR of the port injection SI engine.     

基于主观估计法和FMEDA的失效数据分析及应用

针对安全仪表系统安全完整性等级验证（SIL）和机械装置的失效模式、影响及诊断分析（FMEDA）缺乏特定工厂环境、联锁回路中的产品（如阀门、变送器、逻辑控制器等）失效数据这一关键不足,提出了一种基于主观估计法和皮尔逊卡方检验法的失效数据分析方法,并以丙烯腈反应器出口温度高联锁回路中的气动薄膜调节阀为例,应用该方法估计产品寿命分布和实际失效率;应用机械FMEDA法和故障树（FTA）法对回路进行SIL验证,给出改进措施。结果表明,应用该方法获取的产品失效数据对相应联锁回路进行SIL验证比应用国外通用数据库更准确。     

二维小波提升-DCT变换对地电场压缩算法

为解决10KV架空线路对地电场值海量存储问题,提出一种基于二维小波提升-DCT变换对地电场值压缩算法。将一维对地电场采样值按128×128方阵构成数据块。采用haar小波提升,对该数据块做一层小波分解,得到4个64×64数据块;用二维DCT矩阵对每个64×64数据块变换处理,利用筛选矩阵对DCT系数和小波系数进行筛选;对筛选系数进行一维小波变换编码,完成数据压缩。合理构造筛选系数,可以达到1024∶1高压缩比数据压缩效果。扩大原始数据块大小,压缩比可以达到更高。将其仿真结果与其它算法进行比较,验证了该算法数据压缩的有效性。     

基于FPC和区间编码的工业浮点数据的压缩传输

为解决大量工业浮点数据在GPRS网络上传输时实时性降低的问题,提出了基于科学计算双浮点数压缩算法（FPC）与区间编码相结合的无损压缩方法IFPC实现工业浮点数据的压缩传输及解压缩。先对FPC算法与通用无损压缩算法应用在浮点数部分时的压缩效果作实验对比,实验结果表明FPC算法相比于通用的无损压缩算法在浮点数压缩上具有较好的压缩率以及较短的压缩与解压缩时间。将FPC算法与区间编码结合后的IFPC算法对整个数据域压缩与解压缩的实验结果表明,所提出的方法相比通用无损压缩算法,压缩率最低可提高7.6%,压缩时间最低可减少49.1%,综合传输时间减少了21.3%,提高了传输实时性。     

基于马氏距离的缺失值填充算法

提出了一种基于马氏距离的填充算法来估计基因表达数据集中的缺失数据。该算法通过基因之间的马氏距离来选择最近邻居基因,并将已得到的估计值应用到后续的估计过程中,然后采用信息论中熵值的概念计算最近邻居的加权系数,得到缺失数据的填充值。实验结果证明了该算法具有有效性,其性能优于其他基于最近邻居法的缺失值处理算法。     

A hybrid cost estimation framework based on feature-oriented data mining approach

This paper presents an informatics framework to apply feature-based engineering concept for cost estimation supported with data mining algorithms. The purpose of this research work is to provide a practical procedure for more accurate cost estimation by using the commonly available manufacturing process data associated with ERP systems. The proposed method combines linear regression and data-mining techniques, leverages the unique strengths of the both, and creates a mechanism to discover cost features. The final estimation function takes the user’s confidence level over each member technique into consideration such that the application of the method can phase in gradually in reality by building up the data mining capability. A case study demonstrates the proposed framework and compares the results from empirical cost prediction and data mining. The case study results indicate that the combined method is flexible and promising for determining the costs of the example welding features. With the result comparison between the empirical prediction and five different data mining algorithms, the ANN algorithm shows to be the most accurate for welding operations.