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.

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.

ON EVALUATING THE RUN LENGTH PROPERTIES OF CHARTS WITH ESTIMATED CONTROL LIMITS

X charts with estimated control limits are commonly used in practice and treated as if the in-control process parameters were known. However, the former can behave quite differently from the latter. To understand the differences, it is necessary to study the run length distribution (RLD), its mean (ARL) and standard deviation (SDRL) of the X charts when the control limits are estimated. However, ARL and SDRL are integrals over an infinite region with a boundless integrand, the finiteness has not been proved in literature. In this paper, we show the finiteness and uniform integrability of ARL and SDRL. Furthermore, we numerically evaluate the ARL, SDRL and the RLD using number theory method. A numerical study is conducted to assess the performance of the proposed method and the results are compared with those given by Quesenberry and Chen.

Simultaneous determination of manufacturer’s process mean and production run length,and retailer’s order quantity

In Chen and Liu’s optimum profit model with a traditional production system,they did not consider the effect of product quality on the customer’s demand order quantity,and also ignored the used cost of customers for product.In fact,the customer’s demand quantity is always seriously related to product quality.Hence,in the present paper,we modify Chen and Liu’s model to address the determination of the optimal process parameters by employing the idea of quality loss and single sampling rectifying inspection plan.Assuming that the quality characteristic of the product is normally distributed,Taguchi’s symmetric quadratic quality loss function is applied in evaluating the product quality.Three decision variables,i.e.,the mean of the process characteristic,the production run length of the product and the retailer’s order quantity,are jointly determined in our modified model to maximize the expected total profit of society,which includes both the manufacturer and the retailer.A heuristic solution procedure is developed for this optimization problem,and a numerical example is provided for illustration.From the numerical results,it can be seen that both the sale price per unit and the intercept of the mean demand of the customer are two major(or significant)parameters in the model and should be more accurately estimated in practice.Finally,the quality investment policy is provided to compare its effect on the optimum profit model with quality improvement.

Simultaneous settings of order quantity,wholesale price,production run length,process mean,and warranty period

In this article,the authors propose a modified version of S.L.Chen and Liu’s model with a two-stage production system.Assume that the retailer’s order quantity is concerned with the manufacturer’s selling price and the warranty period of product.The used cost of the customer is measured under the Taguchi’s quadratic quality loss function and concluded in the retailer’s profit function.The quality of the lot for the manufacturer is determined by adopting a two-stage single sampling rectifying inspection plan.The modified economic manufacturing quantity(EMQ)model is addressed in formulating the manufacturer’s expected profit.The retailer’s order quantity,manufacturer’s wholesale price,production run length,process mean,and warranty period of product will be jointly determined by maximizing the total expected profit of the supply chain system including the manufacturer and the retailer.Finally,the quality investment policy is introduced to illustrate the profit improvement for the supply chain system.

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.

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.

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.

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.

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.

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.

面向引信天线罩形变图像的图像压缩算法

为了实现在弹载遥测电台低带宽的条件下引信天线罩形变图像的传输,提出了一种压缩图像质量高且算法复杂度低、易于硬件实现的图像压缩算法。该算法采用空间数据系统咨询委员会(CCSDS)推荐的9/7M小波基对图像进行四级分解,减少图像数据冗余。根据图像特点改进传统的权重分配策略,减少失真信息,确保重构图像的质量。采取并行像素扫描方式,显著缩减多级树集合分裂编码(SPIHT)中多级树结构划分的时间开销。此外,针对图像本身特征引入改进型游程编码(RLE)算法,优化图像数据分类方式,在不损失图像质量的前提下,提高了整体压缩倍率。试验结果表明:与SPIHT及CCSDS标准相比,本算法在结构相似性指数(SSIM)和峰值信噪比(PSNR)方面分别实现了6.92%,16.45%和11.12%,22.56%的增长,而压缩时间相比SPIHT仅增加0.06 s,算法复杂度增幅较小。与主流图像压缩算法相比,在相同的压缩倍率下,本算法在压缩引信天线罩形变图像时,压缩图像质量与JPEG2000算法相近,但压缩时间节省高达35.35%。综上所述,该算法具有复杂度低的特性,其压缩性能可满足弹载系统压缩需求,解压缩图像质量达到主流算法水平。

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。

基于高光谱与纹理特征融合的甘草药材基源鉴别研究

不同甘草的基源鉴别对保障其临床应用具有重要意义。该研究基于乌拉尔甘草、胀果甘草和光果甘草3种基源共89根甘草药材的光谱特征,进一步利用灰度行程矩阵从4个角度(0°、45°、90°和135°)分别提取11个纹理特征参数(短行程强调、长行程强调、灰度不均匀性、行程不均匀性、行程百分比、低灰度行程强调、高灰度行程强调、短行程低灰度强调、短行程高灰度强调、长行程低灰度强调、长行程高灰度强调)对甘草药材进行鉴别,开发了归一化后求平均值的差异度法(NAD),筛选出对基源鉴别贡献较大的5个纹理特征,并将其与光谱特征进行融合,以提高基源鉴别的准确性。与传统的特征筛选方法SKB法、RFE法和SFM法相比,归一化后求平均值的差异度法展现出更高的适用性,支持向量机(SVM)分类器在测试集上的基源鉴别准确率达到了95.28%,高于未筛选(92.22%)、SKB法筛选(95.00%)、RFE法筛选(95.00%)和SFM法筛选(93.89%)的准确率。该研究提出的数据挖掘方法充分利用高光谱的光谱数据和图像数据,将光谱特征和纹理特征进行有机融合,为甘草药材的基源鉴别提供了一种新型无损的检测方法。

延迟焦化装置加热炉不停风机机械清焦实践

中国石油独山子石化分公司1.20 Mt/a延迟焦化装置加热炉每年进行一次机械清焦。清焦期间需停用鼓风机和引风机,造成装置除臭系统和异味治理设施产生的VOCs(挥发性有机物)只能直排大气,会对环境造成污染,需增加临时移动除臭系统,费用约30万元。基于环境保护和提质增效两方面考虑,对不停鼓风机和引风机机械清焦工艺方案进行了可行性分析并工业应用。结果表明:采用不停用鼓风机和引风机机械清焦,加热炉炉管管壁温度可以满足不高于100℃的要求;加热炉烟气NO_(x)质量浓度最高78 mg/m^(3),满足不大于100 mg/m^(3)的环保要求;运行炉室入口可燃气体积分数为0.022%,满足安全生产要求;装置经济效益半年增加247.9万元。

斜齿轮的有效长度和收尾长度的计算

文章基于理论分析并应用Lagrange乘数法以及求解一个一元四次方程,推导得到了与圆柱型齿条配合的斜齿轮所需要的有效长度的解析表达式,并通过SolidWorks软件验证了其正确性。再通过求解一元四次方程,推导得到了斜齿轮的滚齿收尾部分最远端到垂直于工件轴线且包含退刀时滚刀轴线和工件轴线的最短距离线所在平面的距离,即滚齿收尾长度的解析表达式,并通过SolidWorks软件验证了其正确性。这两个表达式为与斜齿轮相关的机械产品的设计提供了重要依据。

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。

胎冠弧弦长与行驶面宽度之比对轮胎性能的影响

以11.00R20全钢子午线轮胎为对象,研究胎冠弧弦长与行驶面宽度之比对轮胎性能的影响。结果表明:胎冠弧弦长与行驶面宽度之比影响轮胎的接地印痕形状以及胎肩部位的剪应力最大值和应变能密度最大值,而对1#—3#带束层的剪应力最大值和应变能密度最大值影响不明显;胎冠弧弦长与行驶面宽度之比取55.5%~55.9%为宜。

基于行程长度纹理特征的焦炭显微图像分类算法

在分析焦炭显微图像各向异性光学组织中片状与纤维状显微图像特征的基础上,通过对纹理特征的差异性的研究,提出了一种基于行程长度纹理特征和支持向量机(Support Vector Ma-chine)的焦炭显微图像分类方法。该方法首先计算焦炭显微图像中4个方向上的行程长度矩阵,利用行程长度矩阵求得对图像纹理具有不同表征能力的纹理特征量,通过对各个特征量的数据分析,选取有效特征量组合作为分类器的训练向量,然后用支持向量机对实验样本进行分类。实验结果表明,该方法能够有效地识别出焦炭各向异性组织中纤维状、片状等不同光学组分。