Trend Autoregressive Model Exact Run Length Evaluation on a Two-Sided Extended EWMA Chart

The Extended Exponentially Weighted Moving Average(extended EWMA)control chart is one of the control charts and can be used to quickly detect a small shift.The performance of control charts can be evaluated with the average run length(ARL).Due to the deriving explicit formulas for the ARL on a two-sided extended EWMA control chart for trend autoregressive or trend AR(p)model has not been reported previously.The aim of this study is to derive the explicit formulas for the ARL on a two-sided extended EWMA con-trol chart for the trend AR(p)model as well as the trend AR(1)and trend AR(2)models with exponential white noise.The analytical solution accuracy was obtained with the extended EWMA control chart and was compared to the numer-ical integral equation(NIE)method.The results show that the ARL obtained by the explicit formula and the NIE method is hardly different,but the explicit for-mula can help decrease the computational(CPU)time.Furthermore,this is also expanded to comparative performance with the Exponentially Weighted Moving Average(EWMA)control chart.The performance of the extended EWMA control chart is better than the EWMA control chart for all situations,both the trend AR(1)and trend AR(2)models.Finally,the analytical solution of ARL is applied to real-world data in the healthfield,such as COVID-19 data in the United Kingdom and Sweden,to demonstrate the efficacy of the proposed method.

Modified DS np Chart Using Generalized Multiple Dependent State Sampling under Time Truncated Life Test

This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data.

Run_Length压缩算法的改进及C++的实现

针对传统的RunLength压缩算法在应对极端数据时所遇到的问题,提出了改进极端数据影响的措施,采取调整计数长度和调整传统RunLength算法的策略,不用特定字符作为压缩标志,而使用特殊字节位来用作压缩标志,并调整了区分计数字节和数据字节的方法.改进后的算法,大大提高了重复数据长度大于63和大于127的数据的压缩率,为RunLength算法有针对性应用提供了改进方案,同时,给出了RunLength压缩算法的C++程序代码.

Exact Run Length Evaluation on a Two-Sided Modified ExponentiallyWeighted Moving Average Chart for Monitoring

A modified exponentially weighted moving average (EWMA) scheme is one of the quality control charts suchthat this control chart can quickly detect a small shift. The average run length (ARL) is frequently used for theperformance evaluation on control charts. This paper proposes the explicit formula for evaluating the average runlength on a two-sided modified exponentially weighted moving average chart under the observations of a first-orderautoregressive process, referred to as AR(1) process, with an exponential white noise. The performance comparisonof the explicit formula and the numerical integral technique is carried out using the absolute relative change forchecking the correct formula and the CPU time for testing speed of calculation. The results show that the ARL ofthe explicit formula and the numerical integral equation method are hardly different, but this explicit formula ismuch faster for calculating the ARL and offered accurate values. Furthermore, the cumulative sum, the classicalEWMA and the modified EWMA control charts are compared and the results show that the latter is better for smalland intermediate shift sizes. In addition, the explicit formula is successfully applied to real-world data in the healthfield as COVID-19 data in Thailand and Singapore.

New Algorithm for Binary Connected-Component Labeling Based on Run-Length Encoding and Union-Find Sets

Based on detailed analysis of advantages and disadvantages of the existing connected-component labeling （CCL） algorithm,a new algorithm for binary connected components labeling based on run-length encoding （RLE） and union-find sets has been put forward.The new algorithm uses RLE as the basic processing unit,converts the label merging of connected RLE into sets grouping in accordance with equivalence relation,and uses the union-find sets which is the realization method of sets grouping to solve the label merging of connected RLE.And the label merging procedure has been optimized：the union operation has been modified by adding the ＂weighted rule＂ to avoid getting a degenerated-tree,and the ＂path compression＂ has been adopted when implementing the find operation,then the time complexity of label merging is O（nα（n））.The experiments show that the new algorithm can label the connected components of any shapes very quickly and exactly,save more memory,and facilitate the subsequent image analysis.

Stride length-velocity relationship during running with body weight support

背景:减重(LBPP)跑步机可用于康复训练或通过减少健康跑步者的有效体重和跑步时产生的冲击力从而增加跑步距离。本研究旨在探讨在跑步过程中减重系统是否会影响跨步长度(SL)-速度以及腿部冲击加速度的关系。方法:受试者(n=10,21.4±2.0岁,72.4±10.3 kg,1.76±0.09 m)完成由特定的减重和速度组合而成的16种跑步条件。测试速度分别为100%,110%、120%以及130%预设速度(2.75±0.36 m/s)。减重情况为0、60%、70%以及80%体重支撑。通过安装在胫骨前侧远端表面的轻质加速计测量SL及腿部冲击加速度。用4×4(速度×减重)重复测量方差对各参数进行分析(α=0.05)。结果:SL和腿部冲击加速度均不受减重和速度的交互影响(p>0.05)。SL在无减重时达到最小(p<0.05);但在60%、70%以及80%减重时并无显著差异(p>0.05)。腿部在无减重时冲击加速度达到最大(p<0.05);同样在60%、70%及80%减重时无显著差异(p>0.05)。SL和腿部冲击加速度随跑速的增加而增大,但与减重与否无关(p<0.05)。结论:跨步长度与腿部冲击加速度之间的关系不受减重状态的影响。

A Dynamic Steganography Method for Web Images with Average Run- Length-Coding

Web page has many redundancies,especially the dynamic html multimedia object.This paper proposes a novel method to employ the commonly used image elements on web pages.Due to the various types of image format and complexity of image contents and their position information,secret message bits could be coded to embed in these complex redundancies.Together with a specific covering code called average run-length-coding,the embedding efficiency could be reduced to a low level and the resulting capacity outperforms traditional content-based image steganography,which modifies the image data itself and causes a real image quality degradation.Our experiment result demonstrates that the proposed method has limited processing latency and high embedding capacity.What’s more,this method has a low algorithm complexity and less image quality distortion compared with existing steganography methods.

Gender Classification Based on Multi-Scale and Run-Length Features

Human faces can convey substantial information about a person,such as his or her age,race,identity,gender,and emotions.Such facial information can be obtained through techniques like human facial tracking and detection,facial recognition,gender classification,emotion recognition,as well as age estimation.Of these,gender classification is particularly important due to its diverse applications in the fields such as video surveillance and commercial advertising.In this thesis,we propose a method of gender classification based on run-length histograms.The proposed method uses a run-length histogram to record the position information of pixels,thereby efficiently improves the recognition rate and makes the technique suitable for a big-data multimedia database.The experimental results show that the proposed method can achieve better accuracy than a multi-scale based method can.

非参数自适应EWMA SR控制图及其变采样间隔设计

本文基于Wilcoxon符号秩(Signed Rank, SR)检验统计量,提出了一种非参数自适应指数加权移动平均(Adaptive Exponentially Weighted Moving Average, AEWMA)控制图。所提出的AEWMA SR控制图结合了非参数统计量的稳健受控性能以及自适应控制图良好的整体偏移检测特性。同时,为了提高固定采样间隔下的非参数AEWMA SR静态控制图对异常偏移的检测效率,本文进一步研究了可变采样间隔(Variable Sampling Intervals, VSI)下的非参数AEWMA SR动态控制图设计问题。使用了Markov链方法计算控制图的精确平均运行链长(Average Run Length, ARL)和平均报警时间(Average Time to Signal, ATS)等性能指标。通过仿真分析比较了VSI AEWMA SR控制图、FSI AEWMA SR控制图和VSI EWMA SR控制图的统计性能。结果表明,所提出的VSI AEWMA SR控制图能兼顾对于不同大小偏移的敏感性,且变采样间隔的动态策略能显著提高控制图的检测效率。

基于正态变换的变样本容量Shewhart比例控制图设计

为了提高Shewhart型比例控制图的监控效率,将其与变样本容量策略结合,提出一种新的比例控制图(VSS Shewhart-RZ*控制图)来监控二元正态变量之比。基于正态变换方法设计了新的比例统计量Z*,以消除样本容量变化对比例控制图设计及使用的不利影响。采用马尔科夫链方法计算了该控制图的平均运行长度和平均样本容量,给出该控制图的参数优化算法。通过仿真分析研究了该控制图的统计性能,并与Shewhart比例控制图进行比较,结果表明VSS Shewhart-RZ*控制图的性能明显优于传统固定样本容量Shewhart比例控制图。

一种相邻游程增量编码的测试数据压缩方案

随着集成电路制造工艺的高速发展,其构造越来越复杂,测试成本也越来越高,而压缩测试数据是降低测试成本的有效方法之一。本文在双游程交替编码基础上,提出了一种相邻游程增量编码的测试数据压缩方案。先通过编码表获得当前游程编码长度N,然后得到当前游程减去前一游程的差值M,当M不为负数且比N-1小时,使用M+1个0表示当前游程。在压缩过程中,通过实时对比两种编码的长度,并选择长度小的编码以进一步压缩数据,实验证明本方案有着良好的压缩效果。

Footfall patterns of a runner with an Achilles tendon rupture

Purpose: This study aims to compare the load and the length of previously ruptured and healthy Achilles tendon(AT) of a recreational runner who used different footfall patterns on each limb during running.Methods: A 41-year-old recreational athlete with a ruptured AT participated in this report. Two force plates and a high-speed motion capture system were used to collect ground reaction force and kinematic data in shod and barefoot running conditions. AT length was measured using ultrasonography and an infrared camera system. AT force was estimated as the active plantar flexion moment divided by AT moment arm during stance phase.Results: The participant used a rearfoot pattern on the affected limb and a forefoot/midfoot pattern on the unaffected limb during shod running,and a forefoot/midfoot pattern during barefoot running. There was no difference between the length of the affected and the unaffected AT. During shod running, the maximal AT force and loading rate were lower in the affected AT versus the unaffected AT. During barefoot running, the affected maximal AT force and loading rate were greater than the unaffected AT.Conclusion: Footfall patterns can be an adaptation to reduce the loading on a previously injured AT. It appears that runners may consider using a rearfoot footfall pattern during running to reduce the stress on the AT.

基于深度卷积自编码器的岩性分类与识别

在地质勘探与地震信号处理中,岩性分类是一个最基本的问题。然而,由于实际的岩性分类涉及到各种复杂的因素与环节,使得传统的统计和机器学习方法难于得到满意的分类准确率,无法在实际应用中进行有效的岩性识别。为了有效地解决这一问题,本文依据测井曲线数据提出了一种基于深度卷积自编码器的神经网络模型及其相应的参数学习算法,来实现有效的岩性分类与识别,并采用游程平滑算法对分类结果中孤立点进行剔除,进一步改善岩性分类的效果。实验结果表明,即使在少量的测井曲线标注样本条件下,本文所提出的深度学习模型也能够显著地提高了岩性分类的准确率,能够达到实际应用的要求。

基于预测误差与位平面编码的密文域可逆信息隐藏算法

随着云计算技术的发展,越来越多的用户使用云备份的方式存储一些重要文件,与此同时,人们对于隐私保护的要求日益增长。密文域可逆信息隐藏是一种可以在密文图像中嵌入秘密信息,保证无错提取秘密信息以及无损恢复原始图像的技术,该技术既保护了载体图像的安全性,又有效地在网络中传递隐私信息,能够应用于云环境实现对用户的隐私保护,受到研究者的广泛关注。针对现有密文域可逆信息隐藏算法嵌入率较低的问题,提出了基于预测误差与位平面编码的密文域可逆信息隐藏算法,该算法重点研究如何在保证安全性和可逆性的同时,实现高嵌入容量。所提算法对图像进行预处理,根据位平面分布的不同分别使用不同的方式编码,在图像中预留出大量空间,通过重排列将预留的空间放在低位平面中;使用密钥生成随机矩阵,对图像进行加密,以保证图像的安全性;将秘密信息嵌入预留的空间中。在接收端,合法接收者能够根据密钥可分离来实现秘密信息的无错提取以及原始图像的无损恢复。与现有算法相比,所提算法具有更高的嵌入率,在BOWS-2、BOSSBase和UCID这3个数据集上平均嵌入率分别达到了3.769 bit/pixel、3.874bit/pixel和3.148bit/pixel,分别比同类算法中性能最好的算法提升了12.5%、6.9%和8.6%。实验结果表明,所提算法能够充分利用图像的冗余性,有效提升嵌入率。

监控不合格品率的MEWMA-p控制图设计

传统Shewhart-p控制图只对单一属性的不合格品率进行监控,在过程发生偏移时有一定的滞后性。为提高不合格品率控制图的精度,提出一种多元指数加权移动平均不合格品率(multivariate exponentially weighted moving average p, MEWMA-p)控制图。该控制图将多个属性的不合格品率应用于多元指数加权移动平均控制图,可同时对多个属性进行监控,并且对于小范围的偏移更加敏感。对比分析同等偏移程度下指数加权移动平均不合格品率(exponentially weighted moving average p, EWMA-p)控制图与MEWMA-p控制图的平均运行长度(average run length,ARL)结果,并通过模拟仿真说明该方法的有效性。

通用型指数加权移动平均控制图的设计

为提高质量控制图监测微小到中等过程偏移的灵敏度,文章提出一种新的用于过程均值监控的通用型指数加权移动平均(UEWMA)控制图,该控制图是EWMA控制图的一般性推广,根据数据特征,自定义选取平滑系数λ_(1),λ_(2),…,λ_(s),使控制效果达到最优;给出UEWMA控制图的均值与控制限的求取方法,并推导出平均运行长度(ARL)和运行长度标准偏差(SDRL);最后,研究平滑系数对该控制图性能的影响,并将其与现有控制图监测微小到中等过程偏移的灵敏度进行比较。研究结果表明,UEWMA控制图通过数据特征设计平滑系数,具有灵活性好、灵敏度高、扩展性强和控制效果好的特点。

基于患者风险的室内质量控制程序对急诊免疫检验项目室内质量控制成本的影响

目的使用具有批长度的Westgard西格玛规则为7个急诊免疫检验项目设计基于患者风险的统计质量控制(SQC)程序,评估其对各项目室内质量控制成本的影响。方法以遂宁市中心医院急诊检验科2022年7月至2022年12月血清降钙素原(PCT)、肌红蛋白(MYO)、肌酸激酶同工酶(CK-MB)、高敏肌钙蛋白I(hs-cTnI)、B型脑钠肽(BNP)、孕酮(PROG)、人绒毛膜促性腺激素(β-HCG)室内质控的累积在控变异系数(CV)作为各检测项目不精密度的估计值,实验室参加国家卫生健康委临床检验中心室间质量评价(EQA)活动中10个批号的百分差值绝对值的均值作为各检测项目偏倚(Bias)的估计值,并以EQA活动的评价标准作为各检测项目的允许总误差(TEa),计算各项目的西格玛度量值(σ),并采用具有批长度的Westgard西格玛规则为各项目设计合适的SQC程序,包括质控规则、质控结果个数(N)、批数(R)及批长度(M)。根据2022年各项目日平均工作量,分别计算各项目现用室内质控控制方案和应用SQC程序后质控品的使用量,以及用于质量控制的试剂使用量,评估SQC程序对室内质量控制成本的影响。结果MYO的σ=5.54,采用1_(3S)/22S/R_(4S)(N=2,R=1)规则,批长度为450个患者样本,结合每日平均工作量,可每21.6d进行1次质控;CK-MB、hs-cTnI、PCT、PROG和β-HCG的σ在4~5,采用1_(3S)/2_(2S)/R _(4S)/4_(1S)(N=4,R=1)规则,批长度为200个患者样本,结合每日平均工作量,各项目依次为每9.6、9.6、20.6、29.5d和23.2d进行1次质控;BNP的σ=3.83,采用1_(3S)/2_(2S)/R _(4S)/4_(1S)/6 X(N=6,R=1)规则,批长度为45个患者样本的SQC程序以及更高频次的室内质量控制活动,结合每日平均工作量,至少每7.3d应进行1次质控。与当前室内质量控制方案相比较,采用基于患者风险的SQC程序后,室内质控中质控品和试剂的年使用量可减少58.90%~95.34%。结论简单直观的“具有批长度的Westgard西格玛规则”可帮助实验室设计个性化的室内质量控制程序,在降低患者风险的同时,可降低实验室室内质量控制成本,建议各实验室积极应用该质量管理工具。

横通管道参数对真空管道列车运行阻力的影响

为了探究横通管道参数(横通管道长度、横通管道间隔、横截面积大小)对真空管道列车运行阻力的影响,本文在Fluent中对不同运行工况的列车进行数值模拟,通过数值模拟得到列车在带横通管道的真空管道交通系统运行时的运行阻力。结果显示,带有横通管道的真空管道列车的运行阻力与单真空管道列车的运行阻力相比大幅降低。随着横通管道长度的增加,列车运行阻力先降低后小幅度上升,管道长度达到8 m时再增加长度对列车运行阻力影响较小;随着横通管道间隔增加,列车运行阻力先增大后降低,间隔达到2.5倍车身长度时,列车受到的运行阻力小幅度波动;随着横通管道横截面直径由1.0 m增大到2.0 m,即横截面积由0.79 m^(2)增大到3.14 m^(2)时,列车运行阻力随着横截面积的增大近似线性下降。

基于霍夫曼行程编码的SLAM算法

针对基于粒子滤波的SLAM算法生成的栅格地图存储效率不高的问题,提出一种基于霍夫曼行程编码的SLAM算法,以解决原有栅格地图的编码冗余和空间冗余问题。该算法在基于粒子滤波的SLAM算法基础上采用霍夫曼行程编码的地图表示方式,根据不同的应用场景,设计出两种霍夫曼行程编码地图的存储方式,当栅格地图的规模较小时,使用定长编码;当栅格地图的规模比较大时,例如大型商场环境,考虑使用变长编码,进一步增广了该地图表示方式的应用范围。仿真和真实场景实验表明,在一定条件下基于霍夫曼行程编码的SLAM算法最多能够减少94.8%的内存消耗,证明了该算法的可行性与有效性。

基于稀疏分解和复合熵编码的电能质量扰动数据高效压缩算法

对于电能质量扰动信号压缩问题,压缩比和重构误差是一对互相矛盾的指标。传统的压缩算法难以同时满足高压缩比和低重构误差的要求。为了同时提高压缩比和减小重构误差,该文提出了一种基于稀疏分解、哈夫曼编码和行程编码的混合压缩算法。首先,使用基于联合字典的稀疏分解算法,将电能质量扰动信号中的暂态分量和稳态分量进行分离;其次,对暂态分量使用小波分析、哈夫曼编码、行程编码算法进行编码压缩,对稳态分量,即基波和谐波分量,则保留其大于设定阈值的部分,进而完成对信号的压缩;最后,仿真信号和实测信号的实验结果表明该算法较对比算法具有更高的压缩比和更低的重构误差,同时证明了其对采样频率和高斯白噪声具有较强的抗干扰能力。