Study on Quality and Safety Trust Early Warning of Dairy Products Based on Statistical Process Control

In order to solve such problems as lack of dynamic evaluation system in evaluation of quality and safety trust of dairy products,and weak awareness of prevention,it is necessary to introduce the statistical process control into the quality and safety trust evaluation system of dairy products,and establish quality and safety trust early warning model for dairy products,so as to determine the control limit of control chart and carry out early warning according to eight criteria. According to the empirical results,the statistical process control is helpful for finding the hidden process risks and providing the necessary basis for enterprises taking positive measures to raise the confidence of consumers.

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT.

Assessing the Awareness and Usage of Quality Control Tools with Emphasis to Statistical Process Control (SPC) in Ethiopian Manufacturing Industries

Introduction: The present work was devoted to assess the awareness and usage of quality control tools with the emphasis on statistical process control in Ethiopian manufacturing industries. Semi structured questionnaire has been employed to executive and technical managers of manufacturing industries of various size and specialism across the country. Stratified random sample method by region was used to select sample industries for the study. The samples used for this study are industries mainly from Oromiya, Addis Ababa, Tigray, Amara, SNNP and Diredawa regions proportional to their size of the available industries. Methods: Exploratory method and descriptive statistics was used for data analysis. Available documents and reports related to quality control policy of the selected companies were investigated. Results and Discussions: The number of manufacturing industries involved in this study was 44. Of the sampled manufacturing industries about 60% are from Oromiya and Addis Ababa regions. It has been reported that 100% of the respondents said that the importance of quality control tools is very important to their organizations’ productivity and quality improvement (Figure 3). Quality control professionals were also asked the extent to which quality control system is working in their industry and majority of the respondents (45%) have indicated that quality control system is working to some extent in their respective industries (Figure 18). Conclusions and Recommendations: Most of the quality department of the industries did not fully recognize the importance of statistical process control as quality control tools. This is mainly due to lack of awareness and motivation of the top managements, shortage of man power in the area, and others together would make it difficult to apply quality control tools in their organization. In general, the industries in Ethiopia are deficient in vigor and found to be stagnant hence less exposed to a highly competitive market and don’t adopt the latest quality control techniques in order to gain knowledge about systems to improve quality and operational performance. We conclude that quality management system has to be established as an independent entity with a real power and hence the quality control department which is responsible for quality can make an irreversible decision with respect to quality of any given product. Moreover, the concerned bodies (government and ministry of industries) should give attention and work together with universities to ensure how these statistical process control techniques could be incorporated in a curriculum of the universities at higher levels in degree and masters programs. Furthermore, different trainings which could improve quality and efficiency of their respective management system should be given as short and long term to the employees including top and middle managers found in various industries relevant to their process.

Multivariate Statistical Process Monitoring and Control: Recent Developments and Applications to Chemical Industry

Multivariate statistical process monitoring and control (MSPM&C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares (PLS) are surveyed in this paper. The four-step procedure of performing MSPM&C for chemical process, modeling of processes, detecting abnormal events or faults, identifying the variable(s) responsible for the faults and diagnosing the source cause for the abnormal behavior, is analyzed. Several main research directions of MSPM&C reported in the literature are discussed, such as multi-way principal component analysis (MPCA) for batch process, statistical monitoring and control for nonlinear process, dynamic PCA and dynamic PLS, and on-line quality control by inferential models. Industrial applications of MSPM&C to several typical chemical processes, such as chemical reactor, distillation column, polymerization process, petroleum refinery units, are summarized. Finally, some concluding remarks and future considerations are made.

VPLS Based Quality and Cost Control for Tennessee Eastman Process

Product quality and operation cost control obtain increasing emphases in modern chemical system engineering. To improve the fault detection power of the partial least square (PLS) method for quality control, a new QRPV statistic is proposed in terms of the VP (variable importance in projection) indices of monitored process variables, which is significantly advanced over and different from the conventional Q statistic. QRPV is calculated only by the residuals of the remarkable process variables (RPVs). Therefore, it is the dominant relation between quality and RPV not all process variables (as in the case of the conventional PLS) that is monitored by this new VP-PLS (VPLS) method. The combination of QRPV and T2 statistics is applied to the quality and cost control of the Tennessee Eastman (TE) process, and weak faults can be detected as quickly as possible. Consequently, the product quality of TE process is guaranteed and operation costs are reduced.

Off-Line Quality Control in Bioproducts Processing: A Case Study in Greece

In the present article we study the production of grape molasses. Data drawn from a specified biolaboratory, are properly analyzed in order to detect factors that affect significantly the Brix value and the volatile acidity of the final product. The ground that is used for planting and a variety of grapes have been taken into account. Off-line statistical quality control techniques have been employed and the outcomes are displayed and discussed in detail.

Memory-Type Control Charts Through the Lens of Cost Parameters

A memory-type control chart utilizes previous information for chart construction.An example of a memory-type chart is an exponentially-weighted moving average(EWMA)control chart.The EWMA control chart is well-known and widely employed by practitioners for monitoring small and moderate process mean shifts.Meanwhile,the EWMA median chart is robust against outliers.In light of this,the economic model of the EWMA and EWMA median control charts are commonly considered.This study aims to investigate the effect of cost parameters on the out-of-control average run lengthðARL_(1)Þin implementing EWMA and EWMA median control charts.The economic model was used to compute the ARL_(1) parameter.The 14 input parameters were identified and the analysis was carried out based on the one-parameter-at-a-time basis.When the input parameters change based on a predetermined percentage,the ARL_(1) is affected.According to the results of the EWMA chart,nine input parameters had an effect andfive input parameters had no effect on the ARL_(1) parameter.Further,only seven of the 14 input parameters had an effect on the ARL_(1) of the EWMA median chart.However,the effect of each input parameter on the ARL_(1) was different.Moreover,the ARL_(1) for the EWMA median chart was smaller than the EWMA chart.This analysis is crucial to observe and determine the input parameters that have a significant impact on the ARL_(1) of the EMWA and EWMA median control charts.Hence,practitioners can obtain an overview of the influence of the input parameters on the ARL_(1) when implementing the EWMA and EWMA median control charts.

A Study of Detection of Outliers for Working and Non-Working Days Air Quality in Kolkata, India: A Case Study

A variety of factors affect air quality, making it a difficult issue. The level of clean air in a certain area is referred to as air quality. It is challenging for conventional approaches to correctly discover aberrant values or outliers due to the significant fluctuation of this sort of data, which is influenced by Climate change and the environment. With accelerating industrial expansion and rising population density in Kolkata City, air pollution is continuously rising. This study involves two phases, in the first phase imputation of missing values and second detection of outliers using Statistical Process Control (SPC), and Functional Data Analysis (FDA), studies to achieve the efficacy of the outlier identification methodology proposed with working days and Nonworking days of the variables NO2, SO2, and O3, which were used for a year in a row in Kolkata, India. The results show how the functional data approach outshines traditional outlier detection methods. The outcomes show that functional data analysis vibrates more than the other two approaches after imputation, and the suggested outlier detector is absolutely appropriate for the precise detection of outliers in highly variable data.

电化学加工表面均匀性的多变量统计过程控制

零件表面粗糙度对其使用性能有重要影响。为了解决零件表面单一粗糙度参数不能全面反映零件加工表面缺陷的问题,提出一种将基于相关性分析和主元分析的多变量统计过程控制应用于电化学光整加工零件表面均匀性评价的方法。设计无表面缺陷和有表面缺陷两个样件进行对比实验,在电化学光整加工之后记录两个样件的多项表面粗糙度参数,先进行多个参数的单变量统计过程控制,再对多个粗糙度参数进行相关性分析和主元分析,得到综合评价值绘制统计控制图。对比分析结果表明:对于存在局部缺陷的表面,相比单一粗糙度参数,采用综合评价控制图检测零件表面缺陷更准确;基于相关性分析和主元分析的多变量统计过程控制是评价电化学光整加工零件表面均匀性的有效方法。

基于二项分布的统计过程控制方法在血液质量控制中的应用研究

目的通过引入统计过程控制(SPC)方法,分析去白细胞悬浮红细胞的质量控制项目,以期在血液质量控制数据的有效应用方面取得进展,并为血液质量的持续改进提供循证依据。方法自2020—2022年,收集了重庆地区6家血站的去白细胞悬浮红细胞质量控制项目检测数据。利用Minitab软件进行统计过程控制分析,绘制p控制图,计算各质控项目的不符合率及其95%置信区间,以及过程能力指数(Z值)。结果根据《全血及成分血质量要求》对去白细胞悬浮红细胞的质量控制项目进行评估,得出外观、储存期末溶血率、无菌试验符合率均为100%。然而,容量、血红蛋白含量、血细胞比容、白细胞残留量的符合率未能达到100%,但均≥75%。通过基于二项分布的p控制图,进一步识别了生产过程的受控状态。在总体符合率满足国标要求的情况下,发现容量、血红蛋白含量、血细胞比容、白细胞残留量在不同机构中存在失控点,并呈现出明显的趋势。各质控项目的不符合率虽均小于25%,但在95%置信水平下,B、C、E、F,4家血站的白细胞残留量显示不符合规定(>25%)。通过构建能力评价指标Z值进行计数资料的过程能力分析,结果显示E机构的容量,以及B、C、F机构的血细胞比容和全部6家血站的白细胞残留量Z值均<2,提示存在质量改进的空间。结论基于二项分布的统计过程控制方法,对血液成分质量控制具有较好的应用价值,能够进一步实现对血液采集、制备和储存过程的实时监控和过程改进。

连续性肾脏替代治疗管路寿命风险预测模型的研究进展

连续性肾脏替代治疗是重症患者重要的生命支持技术,但其管路寿命过早衰竭严重降低了患者治疗的充分性。该文综述了连续性肾脏替代治疗管路寿命风险预测模型的适用人群、预测因子、结局指标、预测性能以及对临床实践的意义。连续性肾脏替代治疗管路寿命的风险预测模型各有侧重,泛化能力有待验证,医护人员在应用时需甄别模型适用范围与预测性能。

多变量统计过程控制技术在药品生产过程中的应用

介绍了多变量统计过程控制(multivariate statistical process control,MSPC)的基本概念和有关背景。描述了MSPC实施的基本流程以及常用统计量与控制图。强调了MSPC在药品生产过程中的重要作用,特别是中药领域,为药品生产过程质量控制方法的选择提供参考。总结了MSPC的优势和不足,并展望了MSPC在药品生产和质量控制方面的发展趋势。

基于SPC的电机生产过程质量监督

为解决电机生产过程质量监督问题,提出一种基于统计过程控制(SPC)图的电机生产过程质量监督方法,分析了具体流程和步骤,实例结果表明,该方法是有效、可行的。

基于氨基酸及特征肽测定的不同产地鸡内金质量研究

目的:建立鸡内金氨基酸及特征肽的含量测定方法,对不同产地鸡内金进行质量评价。方法:采用高效液相色谱法对鸡内金的12个氨基酸类成分进行测定,同时采用超高效液相串联三重四级杆质谱法对鸡内金的2个特征肽进行测定,并采用偏最小二乘法分析(PLS-DA)对测定结果进行分析。结果:18批鸡内金的12种氨基酸成分总含量相对标准偏差(RSD)范围为2.84%~14.01%,鸡源多肽Ⅰ、鸡源多肽Ⅱ含量RSD分别为47.13%、14.62%,均呈现一定的波动,PLS-DA分析结果显示,3批产地山西和3批产地辽宁独自分为一类,9批产地山东与3批产地浙江的样品共同分为一类。结论:本研究建立的鸡内金氨基酸及特征肽的含量测定方法,能较好地评价不同产地的鸡内金质量,可为鸡内金及动物类药材的质量评价提供参考。

无人机自组网中基于优先级和发送概率的低时延MAC协议设计

媒体接入控制(MAC)协议是满足数据传输质量服务需求的一项关键技术,其性能的优劣直接决定了网络的整体运行效率。相较于其他经典MAC协议,基于统计优先级的多址接入(SPMA)协议采用了多优先级接入、信道检测和流量控制等机制,因此它能更好地满足无人机自组网的低时延、区分服务、大规模组网等重要需求。其中,不同优先级阈值是影响该协议性能的关键指标之一,而现有研究中的阈值设置策略会导致无人机自组网吞吐量波动较大的问题。除此之外,在大规模节点组网的情况下,由于特殊的发送机制,该协议面临数据包冲突加剧的问题。针对以上问题,本文提出了一种新的阈值设置方法和低优先级数据概率性接入信道的方法。在大规模节点网络高业务量的情况下,该改进策略根据新的阈值和周期性负载统计的比较结果决定是否延迟或者拒绝相关数据的接入。与此同时,将SPMA协议的多优先级接入机制和排队论基本原理相结合,通过计算设定发送概率对不同低优先级数据进行接入控制。仿真结果表明,所提方法能够使得无人机自组网的吞吐量保持稳定,并为不同类型业务的差异性服务质量(QoS)需求提供良好支持,提高不同优先级数据的首发传输成功率的同时不会带来较大的额外时延损耗,性能优于现有的SPMA协议。

高光谱辐射反演气溶胶光学厚度及质量控制技术研究

为揭示高光谱辐射反演气溶胶光学厚度并研究其质量控制技术,文章基于安徽合肥2021-06-05 T 08:00/2021-06-05 T 16:00晴天数据,采用实际缺测检查、理论范围检查、统计控制等质量控制方法开展了研究。结果表明:研究期间数据无缺测;在理论范围检查剔除的数量极少,并且剔除数据具有时间一致性;统计控制可以有效地将直接辐照度波动值剔除,使反演产品更为准确合理;质量控制后6个波段气溶胶光学厚度均呈现先上升到正午时刻达到最大值后再下降的相同趋势,并且气溶胶光学厚度随波长增大而减小。

汽车制造过程中的螺纹连接质量监控及预警

螺纹连接装配质量对汽车整车制造有着极其重要的作用。介绍了统计过程控制(statistical process control,SPC)在本公司总装车间螺纹连接残余扭矩质量检测过程中的应用,并结合实际案例,分享了过程能力指数(Cpk)对生产系统稳定性预警专项提升项目。

统计过程控制方法在放疗患者计划质控中的应用

目的运用统计过程控制(SPC)方法建立基于电子射野影像设备(Electronic Portal Imaging Device,EPID)在不同部位、不同放疗技术下使用3%/2mm和3%/3mm基准进行伽马分析的容差限值与干预限值。方法分别选取头颈部、胸部、腹部及其他部位的129例IMRT计划和89例VMAT计划使用EPID进行剂量验证,根据每个部位前20例患者计划的伽马通过率结果计算对应的容差限值与干预限值,绘制相应的单值控制图,实时监测各部位所有计划在不同测量基准下的伽马通过率。结果两种放疗技术在3%/3mm基准下,各部位的容差下限均大于97%,干预下限均接近于97%。3%/2mm基准下,各部位的容差下限均大于94%,干预下限均大于92%。结论SPC方法能够实时、有效的监测改进放疗患者计划质控流程,制定不同部位、不同放疗技术在不同测量基准下的个体化容差干预限值,降低失误风险,减少临床事故的发生。

越鞠保和丸中5-羟甲基糠醛的限量检查

目的:建立越鞠保和丸中5-羟甲基糠醛限量检查方法。方法:采用HPLC法,使用Zafex Acutfex PW-C_(18)(250 mm×4.6 mm,5μm)色谱柱;流动相为乙腈-0.1%甲酸水(2∶98);流速:1.0 mL•min^(-1);柱温:40℃;检测波长:284 nm。结果:5-羟甲基糠醛浓度在0.4919~122.98μg•mL^(-1)范围内,r=1.000,线性关系良好,方法平均回收率为97.99%,RSD为0.61%,精密度、重复性等试验结果均符合方法学测定要求。按照拟定限度要求,65批样品共17批不符合规定,不合格率26.15%。结论:建立的方法适用于越鞠保和丸中5-羟甲基糠醛的限度检查,抽样结果表明65批次样品中5-羟甲基糠醛含量差异较大。有必要对其限度进行控制。

应用统计质量控制(SQC)和诺曼图相结合方法对临床血液学常规检验项目风险管理

目的应用统计质量控制(Statistical quality control,SQC)和诺曼图相结合的方法对实验室高通量连续检测的临床血液学检验常规项目设计符合质量控制的方案。方法根据实验室血细胞分析仪各常规项目的σ度量值的大小与风险管理的应用图形工具Sigma-SQC诺曼图相结合,设计实验室临床血液学检验常规项目的起始及过程监控程序。结果对6σ度量值以上的项目白细胞(WBC)和血红蛋白(Hb)采用:起始质控计划采用MR2:13s/22s/R4s多规则,分析样本量为300,PED=0.94;过程监测计划采用:SR1W2.5s,分析批长度300,Pfr=0.01。对σ度量值为4.7的红细胞(RBC)和4.6的血小板(PLT)起始质控计划采用MR4:13s/22s/R4s/41s多规则,分析样本量=300,误差检出率(PED)=1.00;过程监测质控计划:SR2W3s,分析批长度=80,Pfr=0.00。结论本着以起始质控误差检出率最大,过程监测质控的假失控率最低的原则,对实验室临床血液学检验常规项目采用起始质控计划:MR2多规则,分析批长度为80,过程监测质控计划:SR2W3S就可以最大限度减少患者风险,实现实验室质量持续性改进。