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The accuracy of the measurement system is vital for reliable process monitoring using statistical process control charts. The applied chart’s effectiveness depends on the measurement system's performance. Measurement uncertainty can lead to incorrect decisions like unnecessary stops or failure to intervene. In this paper, we investigated the effect of measurement errors on the performance of four well-established combined charts for monitoring the mean of normally distributed processes: Shewhart-CUSUM, Shewhart-Crosier’s CUSUM, Shewhart-EWMA and Shewhart-GWMA charts. To deal with measurement errors we considered the additive measurement error model. Detailed run length profiles of these charts are studied in terms of average run length (ARL), extra quadratic loss, relative ARL, and performance comparison index through Monte Carlo simulations under different sizes of measurement errors. It was found that measurement errors significantly reduce the power of the combined charts. Thus, multiple measurements scheme is incorporated as a remedy to this effect. The Shewhart-Crosier’s CUSUM performed best of four charts, while the Shewhart-EWMA chart did worst. To demonstrate the effect of measurement uncertainty and highlight implications further, a simulated dataset with a shift in the process mean is considered., Validerad;2023;Nivå 2;2023-01-01 (joosat);Licens full text: CC BY License;Funder: Foundation of Nanjing University of Posts and Telecommunications (NY222176); The Excellent Innovation Teams of Philosophy and Social Science in Jiangsu Province (2017ZSTD022); Key Research Base of Philosophy and Social Sciences in Jiangsu

Kvalitetsutveckling – en översikt är avsedd för undervisning i ämnet på grundläggande och avancerad nivå, till exempel i kurser inriktade på organisatoriska frågor eller kvantitativa metoder för att stödja kvalitetsförbättringar. Boken kan också läsas av yrkesverksamma som vill lära sig mer om ämnet...

Railway track maintenance and renewal are vital for railway safety, train punctuality, and travel comfort. Therefore, having cost-effective maintenance is critical in managing railway infrastructure assets. There has been a considerable amount of research performed on mathematical and decision support models for improving the application of railway track maintenance planning and scheduling. This article reviews the literature in decision support models for railway track maintenance planning and scheduling and transforms the results into a problem taxonomy. Furthermore, the article discusses current approaches in optimising maintenance planning and scheduling, research trends, and possible gaps in the related decision-making models.

Quality management (QM) has shown an impressive ability to update and evolve. The purpose of this paper is to highlight themes that have been identified as vital and important for research projects within QM during the coming decade. The paper is also an attempt to initiate research for the emerging 2030 agenda for QM, here referred to as ‘Quality 2030’. This article is based on extensive data gathered during a workshop process conducted in two main steps: (1) a collaborative brainstorming workshop with 22 researchers and practitioners (spring 2019) and (2) an appreciative inquiry summit with 20 researchers and practitioners (autumn 2019). The process produced five collectively elaborated and designed future research themes for QM: (a) systems perspectives applied, (b) stability in change, (c) models for smart self-organising, (d) integrating sustainable development, and (e) higher purpose as QM booster. The process also identified a positive core of QM, defined as core values and aspects in the field and practice that need to be preserved and nurtured in the future., SMICE

The concurrent use of statistical process control and engineering process control involves monitoring manipulated and controlled variables. One multivariate control chart may handle the statistical monitoring of all variables, but observing the manipulated and controlled variables in separate control charts may improve understanding of how disturbances and the controller performance affect the process. In this article, we illustrate how step and ramp disturbances manifest themselves in a single-input–single-output system by studying their resulting signatures in the controlled and manipulated variables. The system is controlled by variations of the widely used proportional-integral-derivative(PID) control scheme. Implications for applying control charts for these scenarios are discussed.

Quality Management. An Introduction is a multi-purpose book designed for both university students and practitioners. In the book, the authors elaborate on the fundamental principles of quality management by connecting it to relevant practices and methods. Why is this book important? Change and improvements, productivity, and focus on customers and other stakeholders are at the top of management agendas. Quality management is about managing change and improvements as well as reaching goals, whatever they may be, as efficiently as possible, and making effective efforts to do so. Scientific methods are the bases for quality management. Furthermore, quality management is a discipline that goes beyond science into the realms of philosophy. It assumes that the changes you seek are improvements, encouraging the idea that the best route is one that leads to improvements not only for yourself but also for other stakeholders. The book focuses on three fundamental themes in quality management: Customer and stakeholder focus, Models and methods for continuous improvements, and Teamwork and organisational aspects of quality management. The book is designed to be supplemented and supported by other in-depth practitioner texts and research articles in various courses in quality management.

Det övergripande syftet med detta projekt har varit att optimera järnvägsunderhållsplanering genom att kombinera statistisk analys av underhållsbehov med modeller för optimerad underhållsplanering. Projektgruppen har arbetat mot syftet via två arbetspaket. Det första arbetspaketet har nyttjat ett datadrivet arbetssätt för att prediktera underhållsbehovet (eller anläggningstillståndet) baserat på tillgängliga spårgeometridata insamlade via mätvagnar. Det andra arbetspaketet har fokuserat på att optimera planering och schemaläggning av underhållsåtgärder för en given sektion och en given tidshorisont, under beaktande av kostnader och säkerhet. De två arbetspaketen har anslutits genom att planering och chemaläggningsmodellering av underhållsåtgärder har baserats på sannolikheten för att geometriavvikelser för ett segment överskrider ett tröskelvärde, exempelvis underhållsgränsen UH1. Detta dokument sammanfattar arbetet och resultaten av de två arbetspaketen och hur de har kombinerats och länkats för att uppnå projektsyftet. I detta projekt användes data från Stambanan genom övre Norrland (del av Malmbanan), bandel 119, dvs. sträckan Boden-Luleå som fallstudieobjekt. Det underhållsarbete som vi har nyttjat för att exemplifiera arbetssättet har varit spårriktning., Samordnad, effektiv planering av järnvägsinfrastrukturunderhåll

Projektet genomfördes som en av Trafikverket och Formas samfinansierat projekt och har pågått mellan 2016 och 2019. Projektet har dels syftat till att studera svensk upphandling av järnvägsunderhåll, dels till att skapa en modell för upphandlingsstrategier och kontraktsutformning. Studien har delats in i tre delstudier: en litteraturstudie; en kvantitativ studie av uppnådda resultat; samt en kvalitativ studie av nyckelpersoners erfarenheter av det upphandlade underhållet. Det huvudsakliga resultatet av litteraturstudien är att området offentlig upphandling av järnvägsunderhåll är outforskat. Två huvudområden framkommer som relevanta för järnvägsunderhåll: samverkan och anläggningskunskap. Den kvantitativa delstudien undersökte om olika kontraktsförutsättningar samvarierat med en kvalitetsparameter: entreprenörens inställelsetid/spårmeter. Här framkommer att fyra faktorer hade signifikant korrelation med kvalitetsparametern: antal driftplatser i kontraktsområdet, antal säkerhetsbesiktningar som genomförts per år, själva kontraktområdet, samt bantypsklass. Intervjustudieresultaten visar att samverkan i de studerade kontrakten präglas av informellt samarbete mellan inblandade personer. Formella samverkansaktiviteter för att stödja den informella samverkansstrukturen saknas. Arbete som utförs enligt inarbetade rutiner kan på kort sikt gynna effektiviteten, men kan också motverka innovation och nya arbetssätt., En modell för offentlig upphandling av underhållstjänster för järnväg

This paper presents graphical methods for monitoring, diagnostics, and prognostics of the condition of railway infrastructure as support to maintenance planning. The paper also uses graphics to aid univariate, bivariate and multivariate analyses of large datasets of secondary data for linear asset condition assessment in the temporal and spatial domains. We present graphical methods useful for evaluating how the asset degrades and how maintenance actions affect the track condition within different time horizons. Hence, the infrastructure manager and the contracted entrepreneur can share a common view of the asset’s current and future condition, as well as maintenance effectiveness., Samordnad, effektiv planering av järnvägsinfrastrukturunderhåll

Engineering process control and high-dimensional, time-dependent data present great methodological challenges when applying statistical process control (SPC) and design of experiments (DoE) in continuous industrial processes. Process simulators with an ability to mimic these challenges are instrumental in research and education. This article focuses on the revised Tennessee Eastman process simulator providing guidelines for its use as a testbed for SPC and DoE methods. We provide flowcharts that can support new users to get started in the Simulink/Matlab framework, and illustrate how to run stochastic simulations for SPC and DoE applications using the Tennessee Eastman process.

The maintenance of railway infrastructure has in several instances been changed from government-based to being based on public procurement, with varying degrees of flexibility for the contractor to design their maintenance work. The purpose of-giving contractors a larger freedom of choice of how to perform maintenance is to stimulate them to innovate and develop their maintenance processes. Since the contracts differ in between and there are changes in government policies over time that affects both existing and new contracts, a comparison between different contracts becomes challenging. A literature review has been conducted to understand the change in procurement strategy and how to encourage contractors to innovate. The research questions include: What procurement strategies are there? How is maintenance evaluated? How does procurement affect the innovation opportunities for entrepreneurs? The literature review focuses on railway maintenance and contract design between client and contractor. In total, 17 articles matched the search criteria and were selected for the review. To have successful maintenance service, five articles suggested partnering as a strategy with common goals in combination with good communication during the entirety of the contract. When selecting incentive plan, four articles mentions that a focus on performance-based incentives in combination with risk management is better rather than actual payment schemes. The reason being that payment is often the main cause of conflicts between client and contractor. The scientific literature suggests that improvement in incentives improves quality of maintenance, decreases delays and technical failures. The conclusion from the literature review is that partnering in railway maintenance is considered successful. With accurate knowledge about railway assets the incentive plan becomes accurate which reduces costs. The literature review is a part of a research project with an overall goal to develop a mode, QC 20180410

Data analytics remains essential for process improvement and optimization. Statistical process control and design of experiments are among the most powerful process and product improvement methods available. However, continuous process environments challenge the application of these methods. In this article we highlight SPC and DoE implementation challenges described in the literature for managers, researchers and practitioners interested in continuous production process improvement. The results may help managers support the implementation of these methods and make researchers and practitioners aware of methodological challenges in continuous process environments