Дисертації з теми "Statistical indicator of the process"
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1
Arendsee, Wayne C. "Development of a Coaxiality Indicator." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2283/.
Повний текст джерелаАнотація:
The geometric dimensioning and tolerancing concept of coaxiality is often required by design engineers for balance of rotating parts and precision mating parts. In current practice, it is difficult for manufacturers to measure coaxiality quickly and inexpensively. This study examines feasibility of a manually-operated, mechanical device combined with formulae to indicate coaxiality of a test specimen. The author designs, fabricates, and tests the system for measuring coaxiality of holes machined in a steel test piece.
Gage Repeatability and Reproducibility (gage R&R) and univariate analysis of variance is performed in accordance with Measurement System Analysis published by AIAG. Results indicate significant design flaws exist in the current configuration of the device; observed values vary greatly with operator technique. Suggestions for device improvements conclude the research.
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Engqvist, Markus, and Soto Karen Mori. "Defining a Process for Statistical Analysis of Vulnerability Management using KPI." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-14723.
Повний текст джерелаАнотація:
In todays connected society, with rapidly advancing technology, there is an interest in offering technical services in our day to day life. Since these services are used to handle sensitive information and money, there are demands for increased information security. Sometimes errors occur in these systems that risk the security for both parties. These systems should be secured to maintain secure operations even though vulnerabilities occur. Outpost24 is one company that specializes in vulnerability management. By using their scanning tool OUTSCAN™, Outpost24 can identify vulnerabilities in network components, such as firewalls, switches, printers, devices, servers, workstations and other computer systems. These results are then stored in a database. Within this study, the authors will work together with Outpost24 towards this data. The goal is to define a process for generation of vulnerability reports for the company. The process will perform a statistical analysis of the data and present the findings. To solve the task a report was created, during which the process was documented. The work began with a background study into Key Performance Indicators (KPIs), in which the most common security KPIs were identified from similar works. A tool was also developed to help with the analysis. This resulted in a statistical analysis using Outpost24’s dataset. By presenting the data formatted by the KPIs, trends could be identified. This showed an overall trend of increasing vulnerabilities and the necessity for organizations to spend resources towards security. The KPIs offer other possibilities, such as creating a baseline for security evaluation using data from one year. In the future, one could use the KPIs to compare how the security situation has changed.
3
Araujo, Tatiana. "Redução das perdas no processo produtivo de uma fábrica de fraldas descartáveis através da implantação do controle estatístico do processo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2004. http://hdl.handle.net/10183/142248.
Повний текст джерелаАнотація:
Esta dissertação aborda a redução das perdas de qualidade em um processo de fabricação de fraldas descartáveis, através da implantação da ferramenta de Controle Estatístico de Processo (CEP), que tem por objetivo analisar e monitorar as principais variáveis e características de qualidade que influenciam no processo produtivo. Depois de implantada a ferramenta do CEP, são propostos alguns indicadores de desempenho para a área de produção da empresa que servirão de base para medir e acompanhar o desempenho de alguns processos, importantes para se atingir e acompanhar as metas de melhoria de qualidade almejadas pela empresa. A dissertação apresenta uma revisão detalhada da literatura abordando a qualidade, as perdas existentes no processo produtivo, o Desdobramento da Função Qualidade (QFD - Quality Function Deployment), o Controle Estatístico do Processo (CEP) e os indicadores de desempenho. Os resultados obtidos através da implantação do CEP mostram que a empresa deve investir na tecnologia do seu processo produtivo, pois em muitos aspectos sua qualidade esbarra na falta da mesma, mas deve se deter também na substituição de alguns fornecedores de suas matérias-primas, além de investir no treinamento de seus operadores, pois os mesmos devem estar constantemente renovando seus conhecimentos para prevenir falhas do processo.This dissertation is about the reduction of the quality losses on a manufacturing process of diapers, through the implantation of the Statistical Process Control (SPC), which main purpose is to analyse and control the main variables and quality characteristics of the process that can inspire the improvement of the productive process. After introduce the tool, will be proposed some performance indicators for the production sector, just for accompanying and control some process in order that the company can reach it's purpose. The dissertation presents a specify revision o f the literature, approa~hing the quality, the losses in the productive process, the Quality Function Deployment (QFD), SPC and the performance indicators. The results gained with the implant of CEP show that the company should invest on the technology o f its manufacturing process, because in many ways the quality collides with a missing policy, but the company should also pay attention to the suppliers ofraw material and maybe replace them. Besides that, the company should invest on training its operator because they should be constantly renovating their knowledge to prevent failure on the process.
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Аксьонова, Людмила Іванівна. "Удосконалення методів оцінювання результативності процесів системи управління якістю (на прикладі підприємств машинобудівної галузі)". Doctoral thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/24476.
Повний текст джерелаАнотація:
Дисертація спрямована на вирішення питань забезпечення стабільного виконання вимог замовників продукції підприємств машинобудівної галузі шляхом удосконалення методів оцінювання результативності системи управління якістю (СУЯ) за рахунок введення кількісних статистичних показників її процесів. Для цього розроблено комплексний підхід до послідовного оцінювання процесів СУЯ, який відрізняється поступовим забезпеченням їх стабільності та зменшенням розсіювання значень їх показників. Запропоновано використовувати число скарг від замовників продукції для оцінки рівня виконання контрактних зобов’язань підприємства. Досліджено можливості методики внутрішнього аудиту (ВА) забезпечувати зменшення числа скарг від замовників та встановлено відмінність у оцінювані результативності процесів життєвого циклу продукції (ЖЦП) та допоміжних. Досліджено фізичну модель статистичного оцінювання результативності процесів ЖЦП, на основі якої розроблено методику їх кількісної оцінки. Удосконалено метод оцінки результативності коригувальних дій. Розроблено методику «Внутрішній аудит СУЯ», яка відрізняється спрощеною процедурою оцінювання при одночасному збереженні високої статистичної надійності висновків аудиту.
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Ibrahim, Kamarul Asri. "Active statistical process control." Thesis, University of Newcastle Upon Tyne, 1989. http://hdl.handle.net/10443/407.
Повний текст джерелаАнотація:
Most Statistical Process Control (SPC) research has focused on the development of charting techniques for process monitoring. Unfortunately, little attention has been paid to the importance of bringing the process in control automatically via these charting techniques. This thesis shows that by drawing upon concepts from Automatic Process Control (APC), it is possible to devise schemes whereby the process is monitored and automatically controlled via SPC procedures. It is shown that Partial Correlation Analysis (PCorrA) or Principal Component Analysis (PCA) can be used to determine the variables that have to be monitored and manipulated as well as the corresponding control laws. We call this proposed procedure Active SPC and the capabilities of various strategies that arise are demonstrated by application to a simulated reaction process. Reactor product concentration was controlled using different manipulated input configurations e.g. manipulating all input variables, manipulating only two input variables, and manipulating only a single input variable. The last two manipulating schemes consider the cases when all input variables can be measured on-line but not all can be manipulated on-line. Different types of control charts are also tested with the new Active SPC method e.g. Shewhart chart with action limits; Shewhart chart with action and warning limits for individual observations, and lastly the Exponentially Weighted Moving Average control chart. The effects of calculating control limits on-line to accommodate possible changes in process characteristics were also studied. The results indicate that the use of the Exponentially Weighted Moving Average control chart, with limits calculated using Partial Correlations, showed the best promise for further development. It is also shown that this particular combination could provide better performance than the common Proportional Integral (PI) controller when manipulations incur costs.
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Lam, Yue-ban, and 林遇品. "Pastoral care as a process indicator of quality schools." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31961010.
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Lam, Yue-ban. "Pastoral care as a process indicator of quality schools." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21304816.
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Van, Bibber Ashley M. "Monitoring Safety Process Performance with Leading Indicator Safety Audits." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1430422992.
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Mulder, Pieter. "Statistical process control of dynamic processes." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289209.
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10
Yu, Yongmin Viveros-Aguilera R. "Some contributions to statistical process control." *McMaster only, 2007.
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11
SIMOES, BRUNO FRANCISCO TEIXEIRA. "STATISTICAL CONTROL OF MULTIPLE STREAM PROCESS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2010. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=16184@1.
Повний текст джерелаАнотація:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOProcessos Multicanal (PMC) estão presentes nas linhas de produção de muitos segmentos industriais, tais como na indústria alimentícia, farmacêutica, de fabricação de aço e de papel. No entanto, há poucos trabalhos na literatura dedicados ao controle estatístico de processos dessa natureza. O trabalho de Boyd (1950) é o primeiro deles. Neste trabalho são descritos os gráficos de controle de grupos (GCG). Este é o procedimento tradicional, recomendado em textos didáticos de CEP como Pyzdek (1992) e Montgomery (até a 3a edição, de 1997). Posteriormente, Mortell e Runger (1995) elaboram um modelo matemático mais realista para PMC, decompondo a fonte de variação do processo em duas componentes distintas: uma, comum a todos os canais e outra, correspondendo à variação individual de cada canal do processo. Tal modelo foi tão bem aceito na literatura que, desde a sua publicação, tem sido utilizado para o desenvolvimento de esquemas de controle mais eficientes para PMC. Dos esquemas desenvolvidos na versão Shewhart, para o controle estatístico das médias das componentes individuais de variação, devem ser destacados os gráficos de controle de Mortell e Runger (1995), de Runger, Alt e Montgomery (1996) e o GCG de Barbosa (2008). Dentre os esquemas mencionados, somente os dois primeiros foram desenvolvidos tanto em uma versão de Shewhart como em uma versão EWMA (Exponentially Weighted Moving Average), visando obter maior sensibilidade a pequenas alterações na média. Esta tese traz novas propostas para PMC bem representados pelo modelo de Mortell e Runger (1995). Propõe-se a análise da eficiência dos gráficos de controle existentes na detecção de aumentos na dispersão de um canal, bem como o desenvolvimento, na versão Shewhart e EWMA, de novos GCG especificamente destinados à sinalização de tais aumentos. Quando não é viável obter mais de uma observação por canal do processo, propõem-se os gráficos: GCG de MR das diferenças em relação ao nível-base (DNB) e GCG EWMA MR DNB. Já para as situações em que é possível obter mais de uma observação por canal, propõem-se: GCG de S(2) e GCG EWMA de ln[S(2)]. É importante ressaltar que todos os trabalhos desenvolvidos na literatura (seguindo o modelo de Mortell e Runger, 1995) foram dedicados exclusivamente ao controle estatístico da média das componentes individuais de variação, portanto, esta tese tem caráter inédito. Além das contribuições mencionadas, visando obter maior sensibilidade a alterações de pequena magnitude na média das componentes individuais, propõe-se e analisa-se uma versão EWMA do GCG de Barbosa (2008), o mais eficiente na versão Shewhart. Adicionalmente, para obter esquemas EWMA mais eficientes, são obtidos os projetos ótimos de todos os esquemas EWMA apresentados nesta tese, incluindo os gráficos de controle de EWMA de R(t) de Mortell e Runger (1995) e de MEWMA de S(2) de Runger, Alt e Montgomery (1996). São analisadas as curvas de desempenho de todos os esquemas de controle para uma variedade de situações. Nas análises de desempenho, pode-se observar que os esquemas propostos nesta tese são os mais eficientes.
In a multiple stream process (MSP), a same quality variable is measured in several streams in parallel. The first tool proposed for monitoring MSPs was the Group Control Chart (GCC) by Boyd (1950). These schemes are recommended in textbooks and guides as Pyzdek (1992) and Montgomery (until 3rd edition, 1997). Its efficiency is impaired by the presence of cross correlation between streams. A useful model for MSPs (Mortell and Runger, 1995) represents the value of the quality variable in each stream at any time t as the sum of a random variable (or stochastic process) but that is common to all streams, which can be called base level, plus the individual variation of each stream relative to the base level. In the literature, three different Shewhart schemes were developed to control the individual variation of each stream: Mortell e Runger (1995), Runger, Alt and Montgomery (1996) and Barbosa (2008). Only the two first ones were developed both in a Shewhart-type and a EWMA (Exponentially Weighted Moving Average) version. All these schemes were devoted to monitoring the mean of the individual components of the streams; to the best of our knowledge, no previous work considered the case of increases in the variance of a stream. In this thesis four different GCCs for monitoring the inner variability of the individual streams are developed: a GCC of S(2), the sample variance of each stream (which is not the same as Runger, Alt and Montgomery’s statistics); a GCC of EWMA[lnS(2)]; a GCC of the Moving Ranges of the residuals of each stream to the estimated base level, and an EWMA version of it. The last two GCCs cater for the case where, at every sampling time, only individual observations per stream are feasible, which is frequent with a large number of streams. Beyond the mentioned contributions, aiming at more sensitivity to the small shifts in the mean of the individual components, this work proposes a EWMA version of the GCC by Barbosa (2008), the most efficient in the Shewhart version. The ARL performance of every one of these schemes is analyzed, in a variety of situations, including the case of increases in the variance of one stream when the schemes are designed for monitoring the means of individual streams. The results show that the proposed schemes are the fastest in detecting special causes that affect one individual stream.
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Arif, Osama Hasan. "Statistical process control by quantile approach." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19285/.
Повний текст джерелаАнотація:
Most quality control and quality improvement procedures involve making assumptions about the distributional form of data it uses; usually that the data is normally distributed. It is common place to find processes that generate data which is non-normally distributed, e.g. Weibull, logistic or mixture data is increasingly encountered. Any method that seeks to avoid the use of transformation for non-normal data requires techniques for identification of the appropriate distributions. In cases where the appropriate distributions are known it is often intractable to implement. This research is concerned with statistical process control (SPC), where SPC can be apply for variable and attribute data. The objective of SPC is to control a process in an ideal situation with respect to a particular product specification. One of the several measurement tools of SPC is control chart. This research is mainly concerned with control chart which monitors process and quality improvement. We believe, it is a useful process monitoring technique when a source of variability is present. Here, control charts provides a signal that the process must be investigated. In general, Shewhart control charts assume that the data follows normal distribution. Hence, most of SPC techniques have been derived and constructed using the concept of quality which depends on normal distribution. In reality, often the set of data such as, chemical process data and lifetimes data, etc. are not normal. So when a control chart is constructed for x or R, assuming that the data is normal, if in reality, the data is nonnormal, then it will provide an inaccurate results. Schilling and Nelson has (1976) investigated under the central limit theory, the effect of non-normality on charts and concluded that the non-normality is usually not a problem for subgroup sizes of four or more. However, for smaller subgroup sizes, and especially for individual measurements, non-normality can be serious problem. The literature review indicates that there are real problems in dealing with statistical process control for non-normal distributions and mixture distributions. This thesis provides a quantile approach to deal with non-normal distributions, in order to construct median rankit control chart. Here, the quantile approach will also be used to calculate process capability index, average run length (ARL), multivariate control chart and control chart for mixture distribution for non-normal situations. This methodology can be easily adopted by the practitioner of statistical process control.
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Wang, Bo Sen. "Statistical process control of process dispersion when parameters are unknown." Thesis, University of Macau, 2007. http://umaclib3.umac.mo/record=b1872930.
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Lanhede, Daniel. "Non-parametric Statistical Process Control : Evaluation and Implementation of Methods for Statistical Process Control at GE Healthcare, Umeå." Thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-104512.
Повний текст джерелаАнотація:
Statistical process control (SPC) is a toolbox to detect changes in the output of a process distribution. It can serve as a valuable resource to maintain high quality in a manufacturing process. This report is based on the work on evaluating and implementing methods for SPC in the process of chromatography instrument manufacturing at GE Healthcare, Umeå. To handle low volume and non-normally distributed process output data, non-parametric methods are considered. Eight control charts, three for for Phase I analysis, and five for Phase II analysis, are evaluated in this study. The usability of the charts are assessed based on ease of interpretation and the performance to detect distributional changes. The later is evaluated with simulations. The result of the project is the implementation of the RS/P-chart, suggested by Capizzi et al (2013), for Phase I analysis. Of the considered Phase I methods (and simulation scenarios), the RS/P-chart has the highest overall probability, of detecting a variety of distributional changes. Further, the RS/P-chart is easily interpreted, facilitating the analysis. For Phase II analysis, the use of two control charts, one based on the Mann-Whitney U statistic, suggested by Chakraborti et al (2008), and one on the Mood test statistic for dispersion, suggested by Ghute et al (2014), have been implemented. These are chosen mainly based on the ease of interpretation. To reduce the detection time for changes in the process distribution, the change-point chart based on the Cramer Von Mises statistic, suggested by Ross et al (2012), could be used instead. Using single observations, instead of larger samples, this chart is updated more frequently. However, this efficiently increases the false alarm rate and the chart is also considered much more difficult to interpret for the SPC practitioner.Statistisk processkontroll (SPC) är en samling verktyg för att upptäcka förändringar, i fördelningen, hos utfallen i en process. Det kan fungera som en värdefull resurs för att upprätthålla en hög kvalitet i en tillverkningsprocess. Denna rapport är baserad på arbetet med att utvärdera och implementera metoder för SPC i en monteringsprocess av kromatografiinstrument på GE Healthcare, Umeå. Åtta styrdiagram, tre för för fas I analys, och fem för fas II analys, studeras i denna rapport. Användbarheten hos styrdiagrammen bedöms efter hur enkla de är att tolka och förmågan att upptäcka fördelningsförändringar. Den senare utvärderas med simuleringar. Resultatet av projektet är införandet av RS/P-metod, utvecklad av Capizzi et al (2013), för analysen i fas I. Av de utvärderade metoderna, (och simuleringsscenarier), har RS/P-diagrammet den högsta övergripande sannolikheten, för att upptäcka en mängd olika fördelningsförändringar. Vidare är metodens grafiska diagram lätt att tolka, vilket underlättar analysen. För fas II analys, har två styrdiagram, ett baserat på Mann-Whitney's U teststatistika, som föreslagits av Chakraborti et al (2008), och ett på Mood's teststatistika för spridning, som föreslagits av Ghute et al (2014), implementerats. Styrkan i dessa styrdiagram ligger främst i dess enkla tolkning. För snabbare identifiering av processförändringar kan styrdiagrammet baserat på Cramer von Mises teststatistika, som föreslagits av Ross et al (2012), användas. Baserat på enskilda observationer, istället för stickprov, har styrdiagrammet en högre uppdateringsfrekvens. Detta leder dock till ett ökat antal falska larm och styrdiagrammet anses dessutom vara avsevärt mycket svårare att tolka för SPC-utövaren.
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Ko, Byeonggeon, and Yang Gao. "Monitoring Exchange Rates by Statistical Process Control." Thesis, Högskolan i Halmstad, Tillämpad matematik och fysik (MPE-lab), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16533.
Повний текст джерелаАнотація:
The exchange rate market has traditionally played a key role in the financial market. The variation of the exchange rate which is called volatility is also an important feature for studying the exchange rate market because the increased volatility may have a negative effect on a nation's economy by increasing the uncertainty in the exchange market. In this paper the volatility of the exchange rate is considered by means of a Heterogeneous Autoregression Conditional Heteroskedastictity (HARCH) Model. It explains the volatility of the exchange rate market well. In addition, it is assumed that at a random time point a change of a parameter in the distribution of the random process underobservation may occur. Some methods such as the Shewhart method, the Culumative Sum Method (CUSUM) and the ExponentiallyWeighted Moving Average Method (EWMA) are investigated within the frames of this change-point problem. In order to evaluate them, Average Run Length (ARL) and Conditional Expected Delay (CED) will be used asperformance measures.
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Yoon, Seongkyu. "Using external information for statistical process control /." *McMaster only, 2001.
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Vermaat, Mattheus Bertus. "Statistical process control in non-standard situations." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam {Host], 2006. http://dare.uva.nl/document/36871.
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Sundholm, Per. "Statistical Process Control for the Sawmill Industry." Thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-112046.
Повний текст джерелаАнотація:
In the sawmill industry, it can be very profitable to monitor the dimensions of sawn boards so that operators quickly can detect errors and take cor-rective action. In this master’s thesis project, Statistical Process Control (SPC) methods have been implemented to achieve this. SPC is a set of statistical methods whose purpose is to minimize the variations in an in-dustrial process. In particular, the SPC method used here is the control chart, which with an upper and lower control limit quantifies the bounds of natural variation. To find the most suitable control chart, five control charts monitoring the process mean, and two monitoring process variability were tested with help of both a simulation study and an empirical evaluation. The result of the evaluation was that the ”Average Moving Range” chart was regarded the most suitable for changes in process mean, and the Range chart was regarded as the best at detecting changes in process variability. Both charts are constructed for individual boards and not subgroups of boards (as is more common) due to compatibility reasons with the existing measurement practice. The two methods were deemed to be quite able to detect process changes, but some results indicate that the methods might work better for double arbour saw lines than single arbour ones.Det kan vara mycket lönsamt för sågverk att övervaka mått på plankor så att personal snabbt kan hitta och åtgärda fel som uppstår i processen. I det syftet har det här masterarbetet gått ut på att implementera statistisk processkontroll (SPC) för råmåttkontroll på sågverk. SPC är en mängd olika statistiska metoder vars syfte är att minimera spridningen i en tillverkningsprocess. Den metod som är i speciellt focus i det här arbetet är det så kallade styrdiagrammet som med en övre och undre gräns kvantifierar hur stor den naturligt förekommande spridningen är. För att finna det mest lämpade styrdiagrammet utvärderades fem styrdiagram som övervakar processens medelvärde och två styrdiagram som övervakar processens spridning. Denna utvärdering bestod både av en simuleringsstudie och tester gjorda för empiriskt data. Utvärderingen resulterade i att det så kallade ”Average Moving Range” diagrammet rekommenderades för övervakning av medelvärde och ett räckviddsstyrdiagram rekommenderades för spridningen. Båda styrdiagrammen konstruerades för enskilda plankor och inte för stickprov av flera plankor (vilket är vanligare) på grund av kompatibelitetsskäl med gängse mätmetodik. De båda metoderna ansågs vara ganska bra på att upptäcka processförändringar men vissa resultat tyder på att metoderna kanske fungerar bättre för sågverk med mötande klingor än enaxliga sågverk.
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Papazoglou, Michael. "Multivariate statistical process control of chemical processes." Thesis, University of Newcastle Upon Tyne, 1998. http://hdl.handle.net/10443/408.
Повний текст джерелаАнотація:
The thesis describes the application of Multivariate Statistical Process Control (MSPC) to chemical processes for the task of process performance monitoring and fault detection and diagnosis. The applications considered are based upon polymerisation systems. The first part of the work establishes the appropriateness of MSPC methodologies for application to modern industrial chemical processes. The statistical projection techniques of Principal Component Analysis and Projection to Latent Structures are considered to be suitable for analysing the multivariate data sets obtained from chemical processes and are coupled with methods and techniques for implementing MSPC. A comprehensive derivation of these techniques are presented. The second part introduces the procedures that require to be followed for the appropriate implementation of MSPC-based schemes for process monitoring, fault detection and diagnosis. Extensions of the available projection techniques that can handle specific types of chemical processes, such as those that exhibit non-linear characteristics or comprise many distinct units are also presented. Moreover, the novel technique of Inverse Projection to Latent Structures that extends the application of MSPC-based schemes to processes where minimal process data is available is introduced. Finally, the proposed techniques and methodologies are illustrated by applications to a batch and a continuous polymerisation process.
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Rothwell, Stuart G. "Multivariate statistical process control of batch processes." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285801.
Повний текст джерела
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Moyne, William P. (William Patrick). "Enhancing MEMS design using statistical process information." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/85725.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 145-148).
by William Patrick Moyne.
Ph.D.
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Su, Fei. "Statistical analysis of non-linear diffusion process." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/2776.
Повний текст джерелаАнотація:
In this paper, we study the problem of statistical inference of continuous-time diffusion processes and their higher-order analogues, and develop methods for modeling threshold diffusion processes in particular. The limiting properties of such estimators are also discussed. We also proposed the likelihood ratio test statistics for testing threshold diffusion process against its linear alternative. We begin in Chapter 1 with an introduction of continuous-time non-linear diffusion processes where I summarized the literature on model estimation. The most natural extension from affine to non-linear model would be piecewise linear diffusion process with piecewise constant variance functions. It can also be considered as a continuous-time threshold autoregressive model (CTAR), the continuous-time analogue of AR model for discrete-time time-series data. The order-one CTAR model is discussed in detail. The discussion is directed more toward the estimation techniques other than the mathematical details. Existing inferential methods (estimation and testing) generally assume known functional form of the (instantaneous) variance function. In practice, the functional form of the variance function is hardly known. So, it is important to develop new methods for estimating a diffusion model that does not rely on knowledge on the functional form of the variance function. In the second Chapter, we propose the quasi-likelihood method to estimate the parameters indexing the mean function of a threshold diffusion model without prior knowledge of its instantaneous variance structure. (and apply to other nonlinear diffusion models, which will be further investigated later.) We also explore the limiting properties of the quasi-likelihood estimators. We focus on estimating the mean function, after which the functional form of the instantaneous variance function can be explored and subsequently estimated from quadratic variation considerations. We show that, under mild regularity conditions, the quasi-likelihood estimators of the parameters in the linear mean function of each regime are consistent and are asymptotically normal, whereas the threshold parameter is super consistent and weakly converges to some non-Gaussian continuous distribution. A notable feature is that the limiting distribution of the threshold parameter admits a closed-form probability density function, which enables the construction of its confidence interval; in contrast, for the discrete-time TAR models, the construction of the confidence interval for the threshold parameter has, so far, not been practically solved. A simulation study is provided to illustrate the asymptotic results. We also use the threshold model to estimate the term structure of a long time series of US interest rates. It is also of theoretical and practical interest that whether the observed process indeed satisfy the threshold model. In Chapter 3, we propose a likelihood ratio test scheme to test the existence of thresholds. It can test for non-linearity. Most importantly, we shall study how to price and predict value processes with nonlinear diffusion processes.be shown, under the null hypothesis of no threshold, the test statistics converges to a central Gaussian process asymptotically. Also the test is asymptotically powerful and the asymptotic distribution of the test statistic under the alternative hypothesis converge to a non-central Gaussian distribution. Further, the limiting distribution is the same as that of its discrete analogues for testing TAR(1) model against autoregressive model. Thus the upper percentage points of the asymptotic statistics for the discrete case are immediately applicable for our tests. Simulation studies are also conducted to show the empirical size and power of the tests. The application of our current method leads to more future work briefly discussed in Chapter 4. For example, we would like to extend our estimation methods to higher order and higher dimensional cases, use more general underlying mean processes, and most importantly, we shall study how to price and predict value processes with nonlinear diffusion processes.
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Sower, Victor E. "The Consequences of Implementing Statistical Process Control." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc332365/.
Повний текст джерелаАнотація:
This study evaluated the changes which occur in manufacturing organizations in the plastic molding industry which implement statistical process control (SPC). The study evaluated changes in product quality, consistency, cost, changes in employee attitudes, and changes in the organization structure which occur after the implementation of SPC. The study was conducted in two phases. Phase 1 consisted of an exploratory field study of a single manufacturing company. Phase 2 consisted of a field survey of three manufacturing companies in the same industry. An unexpected opportunity to evaluate the differences in effects of successful and unsuccessful SPC implementations occurred during the field survey. One plant, whose management assessed their SPC program as being unsuccessful, reported no economic or quality benefits from SPC. Neither did this plant report any changes in the attitudes or behavior of their employees. Neither of these findings was surprising since this plant was the only one of the four study plants which implemented SPC as a quality control program with no participation from the production department. The three plants whose management assessed their SPC programs as being successful reported reduced product variation and a decrease in the proportion of defective product produced as a result of SPC. No consistent evidence was found concerning a reduction in the material required per product resulting from SPC. No consistent evidence was found linking changes in employee attitudes and behavior to the implementation of SPC. The field study found a significant change in the employees1 attitudes toward management but no change in their attitudes toward the company. The field survey found no evidence of change in either dimension. Evidence was found for a change to a more organic structure during SPC training and to a more mechanistic structure during SPC implementation. The final form of the organization was more organic than before SPC. No consistent evidence was found for an increase in hierarchical levels or a reduction in the spans of control within the production departments as a result of SPC. All three of the plants with successful SPC programs increased the size and authority of their technical support staffs as a result of implementing SPC.
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Fuller, Stephen Patrick. "Leveraging Statistical Process Control for continuous improvement of the manufacturing process." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99001.
Повний текст джерелаАнотація:
Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2015. In conjunction with the Leaders for Global Operations Program at MIT.Thesis: S.M., Massachusetts Institute of Technology, Engineering Systems Division, 2015. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 70-71).
Statistical Process Control (SPC) has been applied to manufacturing processes for several decades as a means of ensuring product quality and has become a primary tool for the application of continuous improvement efforts. Continued Process Verification (CPV) is a Food and Drug Administration requirement that requires biopharmaceutical companies, such as Amgen, Inc., to demonstrate control of commercial manufacturing processes. Furthermore, the Food and Drug Administration's guidance on CPV specifically calls for the use of SPC. This thesis suggests including the use of the Akaike information criteria (AIC), a recognized statistical model selection criterion, for objective model selection for the purpose of establishing the most representative control limits in the application of SPC. The most representative control limits are instrumental in eliminating unnecessary use of resources in the evaluation of manufacturing data. Thus, the use of AIC is one way to reduce waste in the entire process of monitoring the manufacturing process, evaluating data, and making improvements to the manufacturing process. In addition, this thesis forms several key concepts for effective use of SPC and continuous improvement efforts when working with contract manufacturing organizations (CMOs). Finally, this thesis will discuss the applicability of the work done related to SPC as the foundation for effectively monitoring, evaluating and improving the manufacturing process.
by Stephen Patrick Fuller.
M.B.A.
S.M.
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Kandananond, Karin. "Performance characterization of Integrated Statistical Process Control systems." Diss., Wichita State University, 2007. http://hdl.handle.net/10057/1491.
Повний текст джерелаАнотація:
Business competition requires organizations to increase their products’ quality and reduce cost at the same time. Statistical process control (SPC) techniques are important tools for monitoring process performance over time to detect special causes. Automatic process control (APC) systems, on the other hand, are utilized to regulate performance relative to a specified target. The literature indicates that combining APC and SPC systems result in integrated SPC (ISPC) systems offering an effective approach to process improvement. The objective of this research was twofold. The first objective was aimed at identifying the various process factors likely to affect the long-term performance of ISPC systems. The process considered was one of discrete parts manufacturing characterized by the integrated moving average model IMA (1, 1). A simulation model was developed to represent system performance in terms of the mean squared error (MSE) of the resulting output and the average run length (ARL) of the SPC chart utilized. Simulated results were analyzed to identify influential factors likely to affect the system performance. The second objective targeted the development of criteria for the economic performance of ISPC systems. Two mathematical cost models were developed utilizing Taguchi’s quadratic loss function and accounted for key characteristics of the process and system design factors. These two models were used to derive criteria for the economic selection of the SPC chart design parameters. It is hoped that the proposed criteria will help practitioners select appropriate charting alternatives to minimize the total cost of operation.Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering
"December 2007."
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Lakshminarayanan, S. "Process characterization and control using multivariate statistical techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq21588.pdf.
Повний текст джерела
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Yang, Hualong, and 阳华龙. "Statistical process control charts with known and estimatedparameters." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50900018.
Повний текст джерелаАнотація:
Monitoring and detection of abrupt changes for multivariate processes are becoming increasingly important in modern manufacturing environments. Typical equipment may have multiple key variables to be measured continuously. Hotelling's 〖T 〗^2and CUSUM charts were widely applied to solve the problem of monitoring the mean vector of multivariate quality measurements. Besides, a new multivariate cumulative sum chart (MCUSUM) is introduced where the target shift mean is assumed to be a weighted sum of principal directions of the population covariance matrix. In practical problems, estimated parameters are needed and the properties of control charts differ from the case where the parameters are known in advance. In particular, it has been observed that the average run length (ARL), a performance indicator of the control charts, is larger when the estimated parameters are used. As a first contribution we provide a general and formal proof of the phenomenon. Also, to design an efficient 〖T 〗^2 or CUSUM chart with estimated parameters, a method to calculate or approximate the ARL function is necessarily needed. A commonly used approach consists in tabulating reference values using extensive Monte-Carlo simulation. By a different approach in thesis, an analytical approximation for the ARL function in univariate case is provided, especially in-control ARL function, which can help to directly set up control limits for different sample sizes of Phase I procedure instead of conducting complex simulation.published_or_final_version
Statistics and Actuarial Science
Master
Master of Philosophy
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Mohd, Yunus Mohd Yusri. "Multivariate statistical process monitoring using classical multidimensional scaling." Thesis, University of Newcastle upon Tyne, 2012. http://hdl.handle.net/10443/1495.
Повний текст джерелаАнотація:
A new Multivariate Statistical Process Monitoring (MSPM) system, which comprises of three main frameworks, is proposed where the system utilizes Classical Multidimensional Scaling (CMDS) as the main multivariate data compression technique instead of using the linearbased Principal Component Analysis (PCA). The conventional method which usually applies variance-covariance or correlation measure in developing the multivariate scores is found to be inappropriately used especially in modelling nonlinear processes, where a high number of principal components will be typically required. Alternatively, the proposed method utilizes the inter-dissimilarity scales in describing the relationships among the monitored variables instead of variance-covariance measure for the multivariate scores development. However, the scores are plotted in terms of variable structure, thus providing different formulation of statistics for monitoring. Nonetheless, the proposed statistics still correspond to the conceptual objective of Hotelling’s T2 and Squared Prediction Errors (SPE). The first framework corresponds to the original CMDS framework, whereas the second utilizes Procrustes Analysis (PA) functions which is analogous to the concept of loading factors in PCA for score projection. Lastly, the final framework employs dynamic mechanism of PA functions as an alternative for enhancing the procedures of the second approach. A simulated system of Continuous Stirred Tank Reactor with Recycle (CSTRwR) has been chosen for the demonstration and the fault detection results were comparatively analyzed to the outcomes of PCA on the grounds of false alarm rates, total number of detected cases and also total number of fastest detection cases. The last two performance factors are obtained through fault detection time. The overall outcomes show that the three CMDS-based systems give almost comparable performances to the linear PCA based monitoring systemwhen dealing the abrupt fault events, whereas the new systems have demonstrated significant improvement over the conventional method in detecting incipient fault cases. More importantly, this monitoring accomplishment can be efficiently executed based on lower compressed dimensional space compared to the PCA technique, thus providing much simpler solution. All of these evidences verified that the proposed approaches are successfully developed conceptually as well as practically for monitoring while complying fundamentally with the principles and technical steps of the conventional MSPM system.
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Lai, Ivan Chung Hang. "Aspects of statistical process control and model monitoring." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340057.
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Kandananond, Karin Weheba Gamal. "Performance characterization of Integrated Statistical Process Control systems /." Diss., A link to full text of this thesis in SOAR, 2007. http://hdl.handle.net/10057/1491.
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Huschka, Kyle. "Using statistical process control to monitor inventory accuracy." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1407.
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Wehrle, William Paul. "Application of dimensional analysis to statistical process modeling." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/39955.
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Tanuwijaya, Willy Perdana. "Statistical control and design optimization in slitting process." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62512.
Повний текст джерелаАнотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75).
The incorrect slitting is the defect waste in slitting process which does not meet the single pack width and crease-to-edge width requirements. It is the highest contributor to the overall defect waste in slitting process at Company X Jurong (CXJ). To address this problem, the key input and output variables were identified. The inputs are the tension settings and knives' positioning, and the output is crease-to-edge width. The objectives are to optimize the tension settings and to achieve a centered process by a proper calibration of knives' positioning. The Design of Experiments (DoE) was conducted to study the significance of tension towards crease-to-edge width variance. For 200 mL pack size, it was found that the variance is constant within the allowable setting range. For 250 mL pack size, it was found that the overall average variance best represents the variance of the data within the allowable range. However, the process is currently off-centered. Therefore, a proper training for detecting any mean shift happening in the process to the operators utilizing the digital camera measurement system is recommended.
by Willy Perdana Tanuwijaya.
M.Eng.
34
Walsh, Michael P. Ph D. Massachusetts Institute of Technology. "Statistical metrology and process control of quantum devices." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/126998.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 169-187).
Quantum emitters, such as color centers (e.g., nitrogen-vacancy color centers in diamond), have a wide range of applications in quantum information processing, bioimaging, and quantum sensing. Such quantum emitters are typically addressed optically and store their quantum state as an electron spin that can subsequently be read out optically. For this process to work effectively, an efficient light-matter interaction must be achieved, which is difficult given the small interaction cross section of an atomic memory with the optical field. In this thesis, I address three problems that relate to the engineering of a quantum device. The first problem centers on the fact that most quantum emitters are randomly positioned throughout their host lattice making it difficult to lithographically pattern structures intended to increase the light-matter interaction. While there is a non-zero chance that a small number of randomly aligned structures will coincide with randomly positioned emitters, when efforts to scale such a system are made the yield drops exponentially. The second problem has to do with scaling. As systems scale up to larger sets of interacting qubits, it becomes increasingly necessary to produce quantum emitters with narrow optical transitions and long spin coherence times. The third problem is related to the development of tools to manage experiments and data in a more robust, team-centric, and structured manner. The automation of systems to measure qubits and devices that enables improvement of each step in the design process will be crucial if efforts to scale devices beyond a handful of qubits are to be successful. Here, I will review the progress that I made in each of these areas.
by Michael P. Walsh.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
35
Pihnastyi, O. M. "Statistical two-level model of the production process." Thesis, Apostrophe, 2011. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42134.
Повний текст джерелаАнотація:
The mathematical model of economical-manufacturing systems with mass production output was constructed. The state of any production system at any time moment is usually given as a point in two-dimensional phase space. The distribution function for the base product is input, and the equation, being analogous to the kinetic equation in Physics, is put down. Both the engineering-production and the generative functions were determined. The closed system of equations for the distribution function moment was put down in the zero approximation. For the closed system of equations of the manufacturing system’s macroscopic state was obtained. The conditions of manufacturing systems stable operating were written down. The connection between the surplus and the pace of base products motion lengthwise the technological chain was shown. The manufacturing process’ disturbed state system of equations for the particular case of the stability theory (the case of one zero roots of the system’s characteristic equation) was considered.
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Kuek, Soon-Chun. "An investigation of cavity pressure as a process and quality indicator in the micro-injection molding process." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1202418181/.
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Ronnestrand, Clinton. "Using control charts to determine if a process is in statistical process control." Online version, 2009. http://www.uwstout.edu/lib/thesis/2009/2009ronnestrandc.pdf.
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Park, Yongro. "A statistical process control approach for network intrusion detection." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6835.
Повний текст джерелаАнотація:
Intrusion detection systems (IDS) have a vital role in protecting computer networks and information systems. In this thesis we applied an SPC monitoring concept to a certain type of traffic data in order to detect a network intrusion.
We developed a general SPC intrusion detection approach and described it and the source and the preparation of data used in this thesis. We extracted sample data sets that represent various situations, calculated event intensities for each situation, and stored these sample data sets in the data repository for use in future research.
A regular batch mean chart was used to remove the sample datas inherent 60-second cycles. However, this proved too slow in detecting a signal because the regular batch mean chart only monitored the statistic at the end of the batch. To gain faster results, a modified batch mean (MBM) chart was developed that met this goal. Subsequently, we developed the Modified Batch Mean Shewhart chart, the Modified Batch Mean Cusum chart, and the Modified Batch Mean EWMA chart and analyzed the performances of each one on simulated data. The simulation studies showed that the MBM charts perform especially well with large signals ?the type of signal typically associated with a DOS intrusion.
The MBM Charts can be applied two ways: by using actual control limits or by using robust control limits. The actual control limits must be determined by simulation, but the robust control limits require nothing more than the use of the recommended limits. The robust MBM Shewhart chart was developed based on choosing appropriate values based on batch size. The robust MBM Cusum chart and robust MBM EWMA chart were developed on choosing appropriate values of charting parameters.
39
Veluswami, Senthilkumar. "Statistical static timing analysis considering process variations and crosstalk." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2545.
Повний текст джерелаАнотація:
Increasing relative semiconductor process variations are making the prediction of
realistic worst-case integrated circuit delay or sign-off yield more difficult. As process
geometries shrink, intra-die variations have become dominant and it is imperative to
model them to obtain accurate timing analysis results. In addition, intra-die process
variations are spatially correlated due to pattern dependencies in the manufacturing
process. Any statistical static timing analysis (SSTA) tool is incomplete without a model
for signal crosstalk, as critical path delays can increase or decrease depending on the
switching of capacitively coupled nets. The coupled signal timing in turn depends on the
process variations. This work describes an SSTA tool that models signal crosstalk and
spatial correlation in intra-die process variations, along with gradients and inter-die
variations.
40
Trip, Albert. "Statistical Process Control in practice let's make it better /." Amsterdam : Amsterdam : Faculteit der Natuurwetenschappen, Wiskunde en Informatica ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/57156.
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Beadles, Joseph W., and Lee W. Schonenberg. "Statistical process control techniques for the telecommunications systems manager." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/38538.
Повний текст джерелаАнотація:
Approved for public release; distribution is unlimited.The purpose of this thesis is to provide personnel, who are undergoing Total Quality Leadership (TQL) implementation at their telecommunications-related command, an understanding of Statistical Process Controls (SPCs) and their potential application to telecommunications issues. Basic SPC tools common to most Total Quality programs are discussed. Advanced SPC methods including Analysis of Means (ANOM), Analysis of Variance (ANOVA), Weibull analysis and Taguchi Methods are also presented. Selected SPC training plans for both naval telecommunication commands and commercial telecommunication industry are examined. Finally, a case study of a telecommunications-related issue is provided to demonstrate an integrated approach to the use of SPCs.
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Yang, Ruodan. "A systematic statistical approach to polypropylene fibre process technology." Thesis, Heriot-Watt University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440329.
Повний текст джерела
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Twigg, Peter Michael. "Statistical process control and fault detection for continuous processes." Thesis, Manchester Metropolitan University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337267.
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Antory, D. D. S. "Fault diagnosis applications using nonlinear multivariate statistical process control." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419456.
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Guh, Ruey-Shiang. "On-line statistical process control : a hybrid intelligent approach." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311818.
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Beadles, Joseph W. Schonenberg Lee W. "Statistical process control techniques for the telecommunications systems manager." Monterey, Calif. : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA249122.
Повний текст джерелаАнотація:
Thesis (M.S. in Telecommunications Systems Management)--Naval Postgraduate School, March 1992.Thesis Advisors: Boger, Dan C. ; Sessions, Sterling D. "March, 1992." Includes bibliographical references (p. 96-98). Also available in print.
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Bjenning, Lovisa. "Implementation of improved fat standardization using statistical process control." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-86215.
Повний текст джерелаАнотація:
The aim of this project was to apply statistical process control (SPC) and measure the variation of fat content in milk in order to improve the standardization, so that the fat content does not change more than 0.03 percentage units from target. Recommendations of how to adjust the standardization should also be developed. The standardization takes place together with pasteurization in one of the three pasteurizers. Thereafter, the milk goes to a common product tank with all the pasteurizers. Samples from the three pasteurizers and the product tank were collected and analyzed on MilkoScan FT2 and the fat content was plotted into Shewhart and cumulative sum (CUSUM) charts. Sampling on the pasteurizers from startup showed that samples should be taken after about 20 minutes, because then the variation is in general smaller. The data from the product tank showed a smaller variation than the pasteurizers. Because the milk from all the pasteurizers is transported into one product tank, it is impossible to know which pasteurizer that is out of control and need to be adjusted. Therefore, the conclusion is that samples should be taken after the pasteurizer and plotted into Shewhart and CUSUM charts. Action limits were achieved from the Shewhart and CUSUM charts, respectively. These are the limits that should be used to determine when adjustments of the pasteurizers are needed, and not the brand limits that are considerably wider. If the measurements fall outside the second limit in the Shewhart chart (three times the standard deviation) or outside the limits (H) in the CUSUM chart, the standardization before the pasteurizer in question should be considered. It is not known if using SPC will improve the fat content to be within 0.03 percent units from target, because the recommendation has not been applied in the process yet, but it going to be that soon.Syftet med detta arbete var att implementera statistisk processtyrning och mäta variationen i mjölkens fetthalt för att kunna förbättra standardiseringen. Detta skulle medföra att fetthalten inte förändras mer än 0,03 procentenheter från målet. Rekommendationer om hur standardiseringen bör justeras av fetthalten i mjölk ska också utvecklas. Standardiseringen sker tillsammans med pastöriseringen i en av de tre pastörerna. Därefter går mjölken till en gemensam produkttank för pastörerna. Prover från de tre pastörerna samt produkttank samlades in om analyserades på MilkoScan FT2 och fetthalten plottades in i Shewhart och Kumulativsumma (CUSUM) diagram. Provtagning från produktstart på pastörerna visade att prover skulle tas efter 20 minuter, eftersom variationerna då är mindre. Data från produkttank visade en lägre variation än hos de tre pastörerna. Eftersom mjölken från pastörerna transporteras till en produkttank är det omöjligt att veta vilken av de tre pastörerna som är utom kontroll och bör justeras. Därför är slutsatsen att proverna ska tas efter pastörerna och plottas in i Shewhart och CUSUM diagram. Åtgärdsgränser togs fram för både Shewhart och CUSUM diagram. Dessa är gränserna som ska användas för att bestämma när justeringar bör göras på pastörerna och inte varumärkesgränserna som är avsevärt bredare. Om ett mätvärde faller utanför den andra gränsen i Shewhart diagrammet eller utanför gränserna (H) i CUSUM diagrammet bör standardiseringen innan pastören i fråga justeras. Det är ännu oklart om standardiseringen kommer förbättras eftersom rekommendationerna inte har applicerats i processen än. Men kommer att göra det i den närmsta framtiden.
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Strong, Mark J. (Mark Joseph). "Statistical methods for process control in automobile body assembly." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10922.
Повний текст джерелаАнотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1996.Includes bibliographical references (p. 117-120).
by Mark J. Strong.
M.S.
49
Iyer, Harikumar, and Saurabh Prasad. "Statistical process control approach to reduce the bullwhip effect." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40105.
Повний текст джерелаАнотація:
Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2007.Includes bibliographical references (leaves 66-68).
The bullwhip effect is a pervasive problem in multi echelon supply chains that results in inefficient production operations and higher inventory levels. The causes of the bullwhip effect are well understood in industry and academia. Quantitative and qualitative solutions to attenuate this effect have been proposed in various research studies. In this research a quantitative solution in the form of a Statistical Process Control (SPC) based inventory management system is proposed that reduces the bullwhip effect while reducing inventory without compromising service level requirements for a variety of products. The strength of this methodology is in its effectiveness in reducing bullwhip for fast moving products in the mature phase of their lifecycles where improving production efficiency and lowering inventory investment are critical. However, fill rate issues are observed for slow moving products and therefore, the methodology is not recommended for such products. Finally, the application of this methodology to reduce the bullwhip effect is illustrated for a product family of a medical devices company. The results for the different classes of products in this family are discussed.
by Harikumar Iyer [and] Saurabh Prasad.
M.Eng.in Logistics
50
el, homani Abdellatif. "NOVEL APPROACHES FOR STATISTICAL PROCESS CONTROL CHARTS PATTERN RECOGNITION." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/dissertations/152.
Повний текст джерелаАнотація:
Fast and accurate recognition of the Statistical Control Chart Patterns (SPCCP) is significant for supervising manufacturing processes to accomplish better control and to make high value products. SPCCP can display eight kinds of patterns: normal, stratification, systematic, increasing trend, decreasing trend, up shift, down shift and cyclic. With the exception of the natural pattern, all other patterns indicate that the supervised manufacturing process is not performing properly and actions need to be taken to correct the problems. This research proposes new approaches, neural networks and neural-fuzzy systems, to the (SPCCP) recognition. This dissertation also investigates the use of features extracted from statistical analysis for simple patterns, and wavelet analysis for concurrent patterns as the components of the input vectors. Results based on simulated data show that the proposed approaches perform better than conventional approaches. Our work concluded that the extracted features improve the performance of the proposed recognizer systems.