Ändra sökning
Avgränsa sökresultatet
12 1 - 50 av 92
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    In-situ measurement in the iron ore pellet distribution chain using active RFID technology2019Ingår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The active radio frequency identification (RFID) technique is used for in-situ measurement of acceleration and temperature in the distribution chain of iron ore pellets. The results of this paper are based on two experiments, in which active RFID transponders were released into train wagons or product bins. RFID exciters and readers were installed downstream in a harbour storage silo to retrieve data from the active transponders. Acceleration peaks and temperatures were recorded. The results imply that in-situ data can aid the understanding of induced stresses along the distribution chain to, for example, reduce pellet breakage and dusting. In-situ data can also increase understanding of product mixing behaviour and product residence times in silos. Better knowledge of stresses, product mixing and residence times are beneficial to process and product quality improvement, to better understand the transportation process, and to reduce environmental impacts due to dusting.

  • 2.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi. Technical university of Denmark .
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    The Revised Tennessee Eastman Process Simulator as Testbed for SPC and DoE Methods2019Ingår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 31, nr 2, s. 212-229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 3.
    Fundin, Anders
    et al.
    School of Innovation, Design and Engineering, Mälardalen University.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Henrik
    Department of Technology Management and Economics, Chalmers University of Technology.
    Gremyr, Ida
    Department of Technology Management and Economics, Chalmers University of Technology.
    Challenges and propositions for research in quality management2018Ingår i: International Journal of Production Economics, ISSN 0925-5273, E-ISSN 1873-7579, Vol. 199, s. 125-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    From its inception, the field of quality management (QM) has been characterised by practice-driven development. Although QM has reached maturity as a field of research based on empirical enquiry, its practitioners still struggle to adapt QM implementations to reap their benefits. This study aims to identify their challenges to better understand how contemporary QM research addresses them. We propose approaches to bridge the potential relevance gaps between research and practice. A Delphi study of QM practitioners in Swedish private and public organisations, several of which operate globally, generated 49 challenges. An exploratory factor analysis was performed to cluster these challenges into themes, and the literature was reviewed to investigate how each theme has been addressed in QM research. The empirical investigation identified three themes related to future QM challenges—organisations' adaptability to rapid changes in the business environment, quality as a strategic concern for business owners, and managerial ownership of quality. By analysing these challenges, six propositions for future research were proposed to reduce potential relevance gaps. Future research should focus on how to make QM a strategic concern for owners, and explore how it can contribute to organisational ambidexterity and adaptability. Research should also determine how context influences the way QM is applied, and investigate how it can improve organisational learning and innovation. Finally, research should indicate how top managers can adopt the responsibilities of quality managers, and explore the ways the principal values of QM can be better integrated into organisations.

  • 4.
    Lundkvist, Peder
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Statistical Methods - Still Ignored?: The Testimony of Swedish Alumni2018Ingår i: Total Quality Management and Business Excellence, ISSN 1478-3363, E-ISSN 1478-3371Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Researchers have promoted statistical improvement methods as essential for product and process improvement for decades. However, studies show that their use has been moderate at best. This study aims to assess the use of statistical process control (SPC), process capability analysis, and design of experiments (DoE) over time. The study also highlights important barriers for the wider use of these methods in Sweden as a follow-up study of a similar Swedish study performed in 2005 and of two Basque-based studies performed in 2009 and 2010. While the survey includes open-ended questions, the results are mainly descriptive and confirm results of previous studies. This study shows that the use of the methods has become more frequent compared to the 2005 study. Larger organisations (>250 employees) use the methods more frequently than smaller organisations, and the methods are more widely utilised in the industry than in the service sector. SPC is the most commonly used of the three methods while DoE is least used. Finally, the greatest barriers to increasing the use of statistical methods were: insufficient resources regarding time and money, low commitment of middle and senior managers, inadequate statistical knowledge, and lack of methods to guide the user through experimentations.

  • 5.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Exploring the Use of Design of Experiments in Industrial Processes Operating Under Closed-Loop Control2017Ingår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 33, nr 7, s. 1601-1614Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrial manufacturing processes often operate under closed-loop control, where automation aims to keep important process variables at their set-points. In process industries such as pulp, paper, chemical and steel plants, it is often hard to find production processes operating in open loop. Instead, closed-loop control systems will actively attempt to minimize the impact of process disturbances. However, we argue that an implicit assumption in most experimental investigations is that the studied system is open loop, allowing the experimental factors to freely affect the important system responses. This scenario is typically not found in process industries. The purpose of this article is therefore to explore issues of experimental design and analysis in processes operating under closed-loop control and to illustrate how Design of Experiments can help in improving and optimizing such processes. The Tennessee Eastman challenge process simulator is used as a test-bed to highlight two experimental scenarios. The first scenario explores the impact of experimental factors that may be considered as disturbances in the closed-loop system. The second scenario exemplifies a screening design using the set-points of controllers as experimental factors. We provide examples of how to analyze the two scenarios

  • 6.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Improved Condition Assessment through Statistical Analyses: Case Study of Railway Track2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Traditional practice within railway maintenance is based on engineering knowledge and practical experience, which are documented in regulations. This practice is often time-based, but can also be condition-based by combining time-based inspections with condition-based actions depending on the inspection results. However, the logic behind the resulting regulation is seldom well documented, which makes it challenging to optimise maintenance based on factors such as operational conditions or new technologies, methodologies and best practices. One way to deal with this challenge is to use statistical analysis and build models that support fault diagnostics and failure prognostics. This analysis approach will increase in importance as automated inspections replace manual inspections. Specific measurement equipment and trains are not the only ones producing automated measurements; regular traffic is increasingly often producing measurements. Hence, there will not be any lack of condition data, but the challenge will be to use this data in a correct way and to extract reliable information as decision support. In this context, it is crucial to balance the risks of false alarms and unrecognised faults, but also to estimate the quality of both data and information. The purpose of this work is to use statistics in order to support improved asset management, by building statistical models as a complement to physical models and engineering knowledge. The resulting models combine theories from the field of time-series analysis, statistical process control (SPC) and measurement system analysis. Charts and plots present results and have prognostic capabilities that allow necessary track possession times to be included in the timetable. 

  • 7.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Managerial implications for improvingcontinuous production processes2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 8.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi. Technical University of Denmark.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    On the structure of dynamic principal component analysis used in statistical process monitoring2017Ingår i: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 167, s. 1-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When principal component analysis (PCA) is used for statistical process monitoring it relies on the assumption that data are time independent. However, industrial data will often exhibit serial correlation. Dynamic PCA (DPCA) has been suggested as a remedy for high-dimensional and time-dependent data. In DPCA the input matrix is augmented by adding time-lagged values of the variables. In building a DPCA model the analyst needs to decide on (1) the number of lags to add, and (2) given a specific lag structure, how many principal components to retain. In this article we propose a new analyst driven method to determine the maximum number of lags in DPCA with a foundation in multivariate time series analysis. The method is based on the behavior of the eigenvalues of the lagged autocorrelation and partial autocorrelation matrices. Given a specific lag structure we also propose a method for determining the number of principal components to retain. The number of retained principal components is determined by visual inspection of the serial correlation in the squared prediction error statistic, Q (SPE), together with the cumulative explained variance of the model. The methods are illustrated using simulated vector autoregressive and moving average data, and tested on Tennessee Eastman process data.

  • 9.
    Aldenlöv, Jens
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Per-Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Gustavsson Kärrbom, Tina
    KTH, Depteartment of Real Estate & Construction Management.
    Public procurement of railway infrastructure maintenance: a literature review2017Ingår i: Proceedings of the 9th Nordic Conference on Construction Economics and Organization / [ed] Buser, M; Lindahl, G; Raisanen, C, Lyngby: Polyteknisk Boghandel og Forlag, 2017, s. 10-21Konferensbidrag (Refereegranskat)
    Abstract [en]

    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 model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a more sustainable railway system.

  • 10.
    Aldenlöv, Jens
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Per-Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Karrbom Gustavsson, Tina
    KTH Royal Institute of Technology, Real Estate and Construction Management .
    Public procurement of railway infrastructuremaintenance: a literature review2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    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 riskmanagement is better rather than actual payment schemes. The reason being that payment is often themain 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 model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a moresustainable railway system.

  • 11.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Collosimo, Bianca Maria
    Department of Mechanical Engineering Politecnico di Milano .
    The ENBIS‐16 quality and reliability engineering international special issue2017Ingår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 33, nr 6, s. 1167-1168Artikel i tidskrift (Refereegranskat)
  • 12.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    A two-step procedure for fault detection in the Tennessee Eastman Process simulator2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    High-technological and complex production processes and high availability and sample frequencies of data in large scale industrial processes need the concurrent development of appropriate statistical control tools and monitoring techniques. Therefore, multivariate control charts based on latent variables are essential tools to detect and isolate process faults.Several Statistical Process Control (SPC) charts have been developed for multivariate and megavariate data, such as the Hotelling T2, MCUSUM and MEWMA control charts as well as charts based on principal component analysis (PCA) and dynamic PCA (DPCA). The ability of SPC procedures based on PCA (Kourti, MacGregor 1995) or DPCA (Ku et al. 1995) to detect and isolate process disturbances for a large number of highly correlated (and time-dependent in the case of DPCA) variables has been demonstrated in the literature. However, we argue that the fault isolation capability and the fault detection rate for processes can be improved further for processes operating under feedback control loops (in closed loop).The purpose of this presentation is to illustrate a two-step method where [1] the variables are pre-classified prior to the analysis and [2] the monitoring scheme based on latent variables is implemented. Step 1 involves a structured qualitative classification of the variables to guide the choice of which variables to monitor in Step 2. We argue that the proposed method will be useful for many practitioners of SPC based on latent variables techniques in processes operating in closed loop. It will allow clearer fault isolation and detection and an easier implementation of corrective actions. A case study based on the data available from the Tennessee Eastman Process simulator under feedback control loops (Matlab) will be presented. The results from the proposed method are compared with currently available methods through simulations in R statistics software.

  • 13.
    Eriksson, Henrik
    et al.
    Chalmers University of Technology, Chalmers tekniska högskola, Teknikens ekonomi och organisation.
    Gremyr, Ida
    Chalmers University of Technology.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Fundin, Anders
    Mälardalens högskola.
    Wiklund, Håkan
    Mid Sweden University.
    Wester, Michael
    SIQ.
    Sörqvist, Lars
    Kungliga tekniska högskolan, KTH.
    Exploring Quality Challenges and the Validity of Excellence Models2016Ingår i: International Journal of Operations & Production Management, ISSN 0144-3577, E-ISSN 1758-6593, Vol. 36, nr 10, s. 1201-1221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: The purpose is to identify and explore important quality-related challenges facing organizations, and how current excellence models incorporate these challenges.Methodology: The article is based on a Delphi study in Swedish organizations, 49 challenges were generated and ranked according to importance. The top 10 ranked challenges were compared to the principles of four excellence models.Findings: The excellence models seem to still be relevant since their content matches many of the challenges identified. The MBNQA and the SIQ models were found to have the most comprehensive coverage, while the ISO model had limited coverage. Research Limitations/Implications: Three areas for further research were identified: 1) how QM can evolve in different contexts with varying needs in terms of adaptive and explorative capabilities, 2) the interfaces of QM and sustainability, and ways to understand how customers and stakeholders can be active contributors to improvements and 3) the roles of the owners and board of directors in QM, and how to organize and distribute responsibilities of the QM work.Practical and Social Implications: Three important challenges could be addressed in upcoming revisions of excellence models: 1) making QM a strategic issue for company owners; 2) involving customers in the improvement activities; and 3) developing processes that are robust, while still easily adaptable.Originality/Value: The Delphi study has identified upcoming challenges in the QM area based on input from 188 quality professionals.

  • 14.
    Englund, Stefan
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Granular Flow and Segregation Behavior2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    1. Purpose of the presentation. Granular materials such as grain, gravel, powder or pellets can be thought as intermediate state of matter: They can sustain shear like a solid up to a point, but they can also flow (Behringer 1995). However, differences in particulate sizes, shapes or densities have been known to cause segregation when granular materials are flowing. Surface segregation has often been studied. The mechanisms of segregation on a surface are described in many articles (Makse 1999)(Gray, Gajjar et al. 2015)(Lumay, Boschini et al. 2013). Descriptions of segregation behaviour of granular flow below surfaces are less common. Literature related to bulk flow mostly describe a bulk containing a variety of granular sizes (Engblom, Saxén et al. 2012)(Jaehyuk Choi and Arshad Kudrolli and Martin,Z.Bazant 2005). Warehouses such as silos or binges constitute major segregation and mixing points in many granular material transport chains. Such warehouses also subject the granular media to flow or impact induced stresses. Traceability in these kind of continues or semi continues granular flow environments face many challenges. Adding in-situ sensors, so called PATs, is one way to trace material in a granular flow. It is, however, difficult to predict if the sensors experience the same physical stresses as the average granules do if the PATs segregate. To contain required electronics, these sensors with casings may need to be made larger than the bulk particles it is supposed to follow. It is therefore important to understand when larger particles segregate and how to design sensor casings to prevent segregation. However segregation of larger sized or different shaped particles added as single objects to homogeny sized particle flow has, to our knowledge not yet been studied and that is the purpose of this study.2. Results. We show the significant factors which affect segregation behaviour and how these modify segregation behaviour. Depending on shape on silo and type of flow during discharge we also show how shape, size and density on individual grains is depending on velocity rate in granular flow. 3. Research Limitations/Implications. The time consuming method of manually retrieving data of each individual particle and surrounding bulk material limit the volume of data that can be retrieved. Further research will implement Particle Image Velocimetry technology (PIV) and customised software to analyse metadata from experiments in a much more efficient way.4. Practical implications. Practical outcome as a result of this research is connected to the ability to trace batches in continues and semi continues supply chains in time and space. The possibility to design a decision model to a specific supply chain for more customized controlled quality and, as far as we know, completely new possibilities related root cause analyses of quality issues in the production or supply chain.5. Value of presentation. Even if the research is made in relation to local mining industry and the supply chain related to iron ore pellets, based on their value of this research, the greatest value is expected to pharmaceutical or any law and regulation controlled industry where it is such efficient traceability of any product on the market is essential.2. Method. Experiments have been performed using granules of different shapes and densities to study flow and segregation behaviour. The experiments have been performed in a transparent 2D model of a silo, designed to replicate warehouses along an iron ore pellets distribution chain. Bulk material consisting of granules representing iron ore have been discharged together with larger objects of different sizes representing sensors or RFID tags. Shape, size and density are modified on the larger objects while studying mixing, flow behaviour and segregation tendencies using video. Video analyses have been used to measure the flow speed and flow distribution of the bulk and of the larger objects. The video material and individual particles is then statistically analysed to clarify significant factors in segregation behaviours related to the size, form and density of the particles. The results are based on Design Expert, Minitab and customized Matlab software.

  • 15.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Capaci, Francesca
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Lag Structure in Dynamic Principal Component Analysis2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose of this PresentationAutomatic data collection schemes and abundant availability of multivariate data increase the need for latent variable methods in statistical process control (SPC) such as SPC based on principal component analysis (PCA). However, process dynamics combined with high-frequency sampling will often cause successive observations to be autocorrelated which can have a negative impact on PCA-based SPC, see Vanhatalo and Kulahci (2015).Dynamic PCA (DPCA) proposed by Ku et al. (1995) has been suggested as the remedy ‘converting’ dynamic correlation into static correlation by adding the time-lagged variables into the original data before performing PCA. Hence an important issue in DPCA is deciding on the number of time-lagged variables to add in augmenting the data matrix; addressed by Ku et al. (1995) and Rato and Reis (2013). However, we argue that the available methods are rather complicated and lack intuitive appeal.The purpose of this presentation is to illustrate a new and simple method to determine the maximum number of lags to add in DPCA based on the structure in the original data. FindingsWe illustrate how the maximum number of lags can be determined from time-trends in the eigenvalues of the estimated lagged autocorrelation matrices of the original data. We also show the impact of the system dynamics on the number of lags to be considered through vector autoregressive (VAR) and vector moving average (VMA) processes. The proposed method is compared with currently available methods using simulated data.Research Limitations / Implications (if applicable)The method assumes that the same numbers of lags are added for all variables. Future research will focus on adapting our proposed method to accommodate the identification of individual time-lags for each variable. Practical Implications (if applicable)The visualization possibility of the proposed method will be useful for DPCA practitioners.Originality/Value of PresentationThe proposed method provides a tool to determine the number of lags in DPCA that works in a manner similar to the autocorrelation function (ACF) in the identification of univariate time series models and does not require several rounds of PCA. Design/Methodology/ApproachThe results are based on Monte Carlo simulations in R statistics software and in the Tennessee Eastman Process simulator (Matlab).

  • 16.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Measurement System Analysis of Railway Track Geometry Data using Secondary Data2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we use secondary data to make a partial measurement system analysis of railway measurement cars and their obtained track geometry data. When a measurement car passes the same track section shortly after the previous passage, such as returning in the other direction after reaching a railway endpoint, the repeated measurements hold information of the measurement uncertainty of that car. Reasons for the measurement uncertainty can be sought in other variables that also are stored in the database, such as the individual car identity, the type of car, the speed of the car during measurement, and the travelled direction of the car. By also considering other known factors during the time of measurement as regressors, such as ground frost periods, enhanced modelling may be achieved and also indicate if such periods should be avoided to improve the measurement data quality.The results of this study suggest that the type of car had the largest influence on measurement variation out of the studied regressors. If the variation of a track geometry property on a track section is studied, the variation component belonging to the type of car can be deducted, improving data quality. We suggest that the method could also be used to find track sections that are prone to large seasonal variation, such as due to ground frost.

  • 17.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Measurement Systems Analysis of Railway Measurement Cars2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose: The presentation proposes ways to understand and quantify the variation component due to the measurement system of railway track properties using subsequent runs from measurement cars.Background: Railway infrastructure conditions are commonly inspected by using measurement cars. The measurements are performed with some regularity, and the inspection frequencies could for instance be set taking into account the common train axle loads, railway speed or load bearing classification, number of trains passing, the known railway condition, or the availability of the measurement cars. By combining different inspections of the same track section, it is also possible to monitor the degradation of the infrastructure over time. Often, the railway system is inspected by many measurement cars, and for single tracks, measurements can be obtained from the car travelling in different directions. The measurements are performed at different speeds, related to random variation, but also to the maximum speeds at which the measurement cars operate. The measurements are also afflicted by external variation sources, some of which are acting with a known direction, such as the wear of the track which increases property variation. Maintenance usually (but not always) result in reduced property variation, whereas other sources such as climate related properties such as spring thaw may induce variation over time, but also induce variation that show a periodic behavior with periods with increasing as well as decreasing property variation. This presentation aims to devise a model for how these variation sources may be separated, with the main aim to classify measurement error, but also to estimate the magnitude of other variation sources.Method: No statistically significant differences were found between repeated measurements of cars travelling back and forth on the single track found at the Swedish Iron ore line. These measurements contain measurement error as well as error due to short term degradation and variation due to measurement. As measurement variance is added, it was concluded that the measurement variation could not be larger than the variation shown by repeat measurements. By comparing repeated measurements over time and subtracting variation due to wear, measurement variation for different cars, measurement speeds and measurement directions was estimated using Generalized Linear Models regression analysis. Co-variation between measurement cars and measurement speeds were accounted for using Ridge regression and Elastic Net regression.Results: The regression analysis shows that whereas both measurement speed and the measurement car individuals correlate with the measurement variation obtained, regularized regression points to the measurement cars as the major variation factor and that different measurement cars have different measurement precisionDiscussion and conclusion: The study demonstrates how repeated measurements from regular process data and thus not obtained using the regular and systematic experimental procedures of measurement system analysis can be used for estimation of the variation components of the measurement system. As a side effect, the sizes of other variation sources, external to the measurement system, can be estimated.

  • 18.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Predictive Modelling for Estimation of Railway Track Degradation2016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadu; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 331-347Konferensbidrag (Refereegranskat)
    Abstract [en]

    The degradation processes affecting railway track condition depends both on the resistance of the track and on the stresses subjected to it. Regarding the stresses, both their magnitudes and cycles are of importance when considering the degradation. Furthermore, the stresses have some regularity and variability in the time domain, while the degradation resistance of a track has some spatial regularity as well as variability. In addition, the condition measurements of track may be both irregular and contain measurement errors. Hence, it is challenging to model the condition of track to enable predictions and condition-based maintenance. However, wear prediction models could help to change large parts of the maintenance practice from predominantly corrective to preventive if both the deterministic and the stochastic components of the wear process can be estimated with sufficient accuracy. In this study, one-step-ahead predictions have been used for establishing prognostic models based on repeated measurements of railway track geometry to estimate track wear properties, degradation rates and stochastic behaviour including measurement errors. The prognostic models have then been used for condition assessment and state predictions. Repeated sampling allows for estimations of measurement errors, but the irregular sampling need to be accounted for by interpolation in the time series modelling approach

  • 19.
    Söderholm, Peter
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Rail breaks: an exploratory case study2016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 519-541Konferensbidrag (Refereegranskat)
    Abstract [en]

    Rail breaks are safety critical failures within railway that may result in derailment, but also delays and cancelled trains. Maintenance is important to both manage the causes of rail breaks and to reduce their unwanted consequences. The purpose of this study is to explore the relationship between maintenance practice, rail breaks and their consequences, to achieve an increased understanding of the rail break phenomenon and promote continuous improvement. To fulfil the purpose, an explorative case study at Trafikverket (Swedish transport administration) was performed. The empirical data was collected from databases that contains information about preventive and corrective maintenance, as well as traffic and traffic disturbances related to rail breaks. The analysis was founded on theories from the three fields of time series analysis, reliability analysis of repairable systems, and multivariate data analysis. The findings of the study support an increased understanding of the process of rail break development and occurrence, but also related maintenance efforts.

  • 20.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Simulating Experiments in Closed-Loop Control Systems2016Ingår i: ENBIS-16 in Sheffield, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design of Experiments (DoE) literature extensively discusses how to properly plan, conduct and analyze experiments for process and product improvement. However, it is typically assumed that the experiments are run on processes operating in open-loop: the changes in experimental factors are directly visible in process responses and are not hidden by (automatic) feedback control. Under this assumption, DoE methods have been successfully applied in process industries such as chemical, pharmaceutical and biological industries.

    However, the increasing instrumentation, automation and interconnectedness are changing how the processes are run. Processes often involve engineering process control as in the case of closed-loop systems. The closed-loop environment adds complexity to experimentation and analysis since the experimenter must account for the control actions that may aim to keep a response variable at its set-point value.  The common approach to experimental design and analysis will likely need adjustments in the presence of closed-loop controls. Careful consideration is for instance needed when the experimental factors are chosen. Moreover, the impact of the experimental factors may not be directly visible as changes in the response variables (Hild, Sanders, & Cooper, 2001). Instead other variables may need to be used as proxies for the intended response variable(s).

    The purpose of this presentation is to illustrate how experiments in closed-loop system can be planned and analyzed. A case study based on the Tennessee Eastman Process simulator run with a decentralized feedback control strategy (Matlab) (Lawrence Ricker, 1996) is discussed and presented. 

  • 21.
    Siva, Vanajah
    et al.
    Chalmers University of Technology.
    Gremyr, Ida
    Chalmers University of Technology.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Zobel, Thomas
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Isaksson, Raine
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    The Support of Quality Management for Sustainable Development: A Literature Review2016Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 138, nr 2, s. 148-157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quality Management is considered to be suitable as support forthe integration of sustainability considerations in areas such as productdevelopment. The purpose of this paper is to review research in whichQuality Management methods, tools or practices have been used inconjunction with sustainable development initiatives. We have identifiedfour themes that synthesize the research on Quality Management and itssupport to approaches for sustainable development: (1) supportingsustainability through integration of management systems, (2) QualityManagement as support to the implementation of Environmental ManagementSystems and to the management of sustainability, (3) supportingintegration of sustainability considerations in daily work, and (4)supporting stakeholder management and customer focus. By far the mostresearch has been conducted within the first two themes. This paper alsocontributes with proposals for future research, such as the need to movebeyond existing standards and management systems to enable more radicalimprovements, and the need for empirical evidence of the effect ofintegrated management systems on environmental performance. We alsohighlight the point that Quality Management practices and tools must bedeveloped and adapted in order to support sustainability considerations.

  • 22.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Analysis of an unreplicated 2^2 factorial experiment performed in a continuous process2015Ingår i: Total quality management and business excellence (Online), ISSN 1478-3363, E-ISSN 1478-3371, Vol. 26, nr 9-10, s. 1083-1094Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a tentative analysis method for unreplicated factorial designs where regular statistical experimental analysis cannot be used. The methodology is demonstrated through the analysis of an unreplicated two-level, two-factor factorial experiment performed in a continuous production process where the process was not in statistical control and where changes in the experimental design made conventional experimental analysis impossible. The first step of the analyses included screening of the sampled data. Principal component analysis and factor analysis were then used to create an overview of how the various responses and experimental factors were related. Carbon monoxide efficiency was selected as the most important parameter to be analysed further. Elastic net regression was used as a screening tool to remove non-significant factors, interaction, and covariates. Finally, the carbon monoxide efficiency variation was modelled using an intervention analysis. Two experimental factors were found to actively influence the response. The experiment that from other perspectives can be considered to be unanalysable, did thus reveal causal effects. The results imply that for processes where the process dynamics may be monitored, observations of the process dynamics may reduce the needs for repeated experimental runs, thus reducing the experimental costs.

  • 23.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Control Charts supporting Condition-Based Maintenance of Linear Railway Infrastructure Assets2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 2, s. 7-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a control chart approach for monitoring, diagnostics and prognostics to support condition-based maintenance (CBM) using condition data of linear railway infrastructure assets. The condition data were obtained from regular inspections done by a railway track measurement wagon. The condition data were statistically analysed by using two different control charts to evaluate the possibility for earlier detection of derailment hazardous faults using both temporal and spatial information.The study indicates that that the proposed control chart approach can be used for condition assessment of track and thereby provides valuable decision support for CBM. The control chart for condition information in the temporal domain supports diagnostics, while the control chart for condition information in the spatiotemporal domain also supports prognostics. The two proposed control charts give earlier fault warnings compared to the traditional approach. This facilitates decisions regarding CBM actions with an extended planning horizon and gives the possibility to increase the operational availability of track.

  • 24.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Data Analysis for Condition-Based Railway Infrastructure Maintenance2015Ingår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 31, nr 5, s. 773-781Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Condition assessment is crucial to optimize condition-based maintenance actions of assets such as railway infrastructure, where a faulty state might have severe consequences. Hence, railways are regularly inspected to detect failure events and prevent the inspected item (e.g. rail) to reach a faulty state with potentially safety critical consequences (e.g. derailment). However, the preventive measures (e.g. condition-based maintenance) initiated by the inspection results may cause traffic disturbances, especially if the expected time to a faulty state is short. The alarm limits are traditionally safety related and often based on geometrical properties of the inspected item. Maintenance limits would reduce the level of emergency, producing earlier alarms and increasing possibilities of planned preventive rather than acute maintenance. However, selecting these earlier maintenance limits in a systematic way while balancing the risk of undetected safety-critical faults and false alarms is challenging. Here, we propose a statistically based approach using condition data of linear railway infrastructure assets. The data were obtained from regular inspections done by a railway track measurement wagon. The condition data were analysed by a control chart approach to evaluate the possibility for earlier detection of derailment hazardous faults using both temporal and spatial information. The study indicates that that the proposed approach could be used for condition assessment of tracks. Control charts led to earlier fault warnings compared to the traditional approach, facilitating planned condition-based maintenance actions and thereby a reduction of track downtime

  • 25.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Project: DISIRE2015Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 26.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Projekt: Förbättrad tillståndsbedömning genom statistisk analys2015Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 27.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Per-Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Karrbom Gustavsson, Tina
    Arkitektur och samhällsbyggnad, KTH, Sverige.
    Projekt: Offentlig upphandling av järnvägsunderhåll2015Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 28.
    Kulahci, Murat
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Capaci, Francesca
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Projekt: Statistiska metoder för förbättring av kontinuerliga tillverkningsprocesser2015Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 29.
    Capaci, Francesca
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Simulating and Analyzing Experiments in the Tennessee Eastman Process Simulator2015Ingår i: ENBIS-15, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In many of today’s continuous processes, the data collection is usually performed automatically yielding exorbitant amount of data on various quality characteristics and inputs to the system. Moreover, such data are usually collected at high frequency introducing significant serial dependence in time. This violates the independent data assumption of many industrial statistics methods used in process improvement studies. These studies often involve controlled experiments to unearth the causal relationships to be used for robustness and optimization purposes.

    However real production processes are not suitable for studying new experimental methodologies, partly because unknown disturbances/experimental settings may lead to erroneous conclusions. Moreover large scale experimentation in production processes is frowned upon due to consequent disturbances and production delays. Hence realistic simulation of such processes offers an excellent opportunity for experimentation and methodological development.

    One commonly used process simulator is the Tennessee Eastman (TE) challenge chemical process simulator (Downs & Vogel, 1993)[1]. The process produces two products from four reactants, containing 41 measured variables and 12 manipulated variables. In addition to the process description, the problem statement defines process constraints, 20 types of process disturbances, and six operating modes corresponding to different production rates and mass ratios in the product stream.

    The purpose of this paper is to illustrate the use of the TE process with an appropriate feedback control as a test-bed for the methodological developments of new experimental design and analysis techniques.

    The paper illustrates how two-level experimental designs can be used to identify how the input factors affect the outputs in a chemical process.

    Simulations using Matlab/Simulink software are used to study the impact of e.g. process disturbances, closed loop control and autocorrelated data on different experimental arrangements.

    The experiments are analysed using a time series analysis approach to identify input-output relationships in a process operating in closed-loop with multivariate responses. The dynamics of the process are explored and the necessary run lengths for stable effect estimates are discussed.

  • 30.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Some ideas why factorial designs are not used in full-scale experiments in continuous processes2015Ingår i: Total quality management and business excellence (Online), ISSN 1478-3363, E-ISSN 1478-3371, Vol. 26, nr 11-12, s. 1242-1254Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents ideas and observations about the infrequent use of factorial experimental designs; although the ideas presented are inspired by a case study, the paper is also conceptual in nature. The ideas build on the experimental practices at a large Swedish process industry manufacturer, where these practices were discussed with engineers using in-depth interviews. Factorial design is not used because, for example, statistical rigor is seldom required and because design of experiments methods are seen as too restrictive to accommodate and adjust to events occurring during long experimental campaigns. The interview results indicate that, while the scepticism of many respondents may be justified, lack of training, interest, and learning time are major obstacles to applying improved methodologies. Some ideas for overcoming these obstacles are suggested.

  • 31.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Trafikverket.
    Control Charts supporting Condition-Based Maintenance of Linear Railway Infrastructure Assets2014Ingår i: Proceedings of the 3rd international workshop and congress on eMaintenance: June 17-18 Luleå, Sweden : eMaintenance, Trends in technologies & methodologies, challenges, possibilites and applications / [ed] Uday Kumar; Ramin Karim; Aditya Parida; Philip Tretten, Luleå: Luleå tekniska universitet, 2014, s. 101-107Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a control chart approach for monitoring,diagnostics and prognostics to support condition-basedmaintenance (CBM) using condition data of linear railwayinfrastructure assets. The condition data were obtained fromregular inspections done by a railway track measurement wagon.The condition data were statistically analysed by using twodifferent control charts to evaluate the possibility for earlierdetection of derailment hazardous faults using both temporal andspatial information. The study indicates that that the proposedcontrol chart approach can be used for condition assessment oftrack and thereby provide valuable decision support for CBM. Thecontrol chart for condition information in the temporal domainsupports diagnostics, while the control chart for conditioninformation in the spatiotemporal domain also supportsprognostics. The two proposed control charts give earlier faultwarnings compared to the traditional approach. This facilitatesdecisions regarding CBM actions with an extended planninghorizon and gives the possibility to increase the operationalavailability of track.

  • 32.
    Lundkvist, Peder
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Experimental Study of Oscillation Mark Depth in Continuous Casting of Steel2014Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 41, nr 4, s. 304-309Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mould oscillation is needed to reduce friction and thus prevent sticking and breakout of the liquid metal during casting. However, this oscillation is known to cause surface defects in the solidified steel slabs, so called oscillation marks. In this paper, the depth and the depth variation of these oscillation marks were studied using a two-level full factorial experiment (24) with four additional centre point runs. Four factors were studied: stroke length of the mould, oscillation frequency, motion pattern (strip factor) and casting speed. The stroke length affected the depth of the marks the most, where larger strokes created deeper marks. The interaction between the oscillation frequency and the strip factor of the mould also affected the oscillation mark depth. The oscillation mark depth variation was also increased by increased stroke lengths and at higher oscillation frequencies. The largest effect on the oscillation depth variation was found for the interaction between the stroke length and the oscillation frequency.

  • 33.
    Holmbom, Martin
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Performance-based logistics: an illusive panacea or a concept for the future?2014Ingår i: Journal of Manufacturing Technology Management, ISSN 1741-038X, E-ISSN 1758-7786, Vol. 25, nr 7, s. 958-979Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose– The purpose of this paper is to summarize previously reported benefits, drawbacks and important aspects for implementation of performance-based logistics (PBL), and to identify knowledge gaps.Design/methodology/approach– This is a literature review based on 101 articles. The reviewed articles are relevant to PBL in particular, but also to performance contracting, product-service systems (PSS) and servitization in general. The research method involved database searches, filtering results and reviewing publications.Findings– PBL is a business concept that aims to reduce the customer's total costs for capital-intensive products and increase the supplier's profit. The design of the contract, performance measurements and payment models are important aspects for successful implementation. However, the authors find a reason for concern to be the lack of empirical evidence of the profitability of PBL for the customer and the supplier.Originality/value– This literature review of PBL also includes publications from the related research areas: performance contracting, PSS and servitization. Developing PBL can benefit from results in these research areas.

  • 34.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Westerberg, Mats
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Testing for motivation to engage in improvements: a conceptual framework and an initial empirical test2014Ingår i: Total quality management and business excellence (Online), ISSN 1478-3363, E-ISSN 1478-3371, Vol. 25, nr 11-12, s. 1224-1235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper aims to develop a conceptual framework for testing the motivation to engage in improvement work. The framework is based on Ajzen's theory of planned behavior (TPB), that we suggest can be used to facilitate the implementation of improvement programmes. By using the model and probing intentions, attitudes, norms and perceived ability related to improvement work, we believe hindrances for implementation of improvement programmes will be exposed. When operationalising the framework we developed a survey instrument based on TPB and then made an initial empirical test by distributing it to 124 employees (response rate 67%) of three manufacturing small- and medium-sized enterprises. Factor analysis and regression were used to analyse the survey and follow-up interviews with employees and managers were used to validate the results. This initial test of the instrument showed that it has sound measurement properties, indicated by clear factor structure and good internal consistency. Interview data also validated that the instrument was able to capture important aspects related to implementation of improvement work. Based on the result, we conclude that TPB may be useful for guiding management actions. However, since our study only draws on a limited empirical sample, future research is needed to test the contextual validity.

  • 35.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Evaluating Quality of Higher Education by Assessing its Output: The Swedish Example2013Ingår i: 16th QMOD-ICQSS Proceedings: Quality Management and Organizational Development Conference / [ed] Su Mi Dahlgaard Park, Moderna Organizacija , 2013, s. 216-222Konferensbidrag (Refereegranskat)
  • 36.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Power Analysis of Methods for Analysing Unreplicated Factorial Experiments2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Several methods for formal analysis of unreplicated factorial type experiments have been proposed in the literature. Based on a simulation study, five formal methods found in the literature based on the effect sparsity principle have been studied. The simulation included 23 and 24 type factorials with one, two, or four active effects. The simulated signal-to-noise ratios for the effects were all between two and four, and the Type I and Type II errors of the analysis methods were analysed. Preliminary results show that Bayesian models are more powerful in these contexts, especially if informative priors based on the effect heredity and effect hierarchy principles are used.

  • 37.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Towards improved analysis methods for two-level factorial experiments with time series responses2013Ingår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 29, nr 5, s. 725-741Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dynamic processes exhibit a time delay between the disturbances and the resulting process response. Therefore, one has to acknowledge process dynamics, such as transition times, when planning and analyzing experiments in dynamic processes. In this article, we explore, discuss, and compare different methods to estimate location effects for two-level factorial experiments where the responses are represented by time series. Particularly, we outline the use of intervention-noise modeling to estimate the effects and to compare this method by using the averages of the response observations in each run as the single response. The comparisons are made by simulated experiments using a dynamic continuous process model. The results show that the effect estimates for the different analysis methods are similar. Using the average of the response in each run, but removing the transition time, is found to be a competitive, robust, and straightforward method, whereas intervention-noise models are found to be more comprehensive, render slightly fewer spurious effects, find more of the active effects for unreplicated experiments and provide the possibility to model effect dynamics.

  • 38.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Henrik
    Chalmers University of Technology.
    Hallencreutz, Jacob
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle.
    Langstrand, Jostein
    Linköpings universitet.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Zobel, Thomas
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Alive and kicking – but will Quality Management be around tomorrow?: A Swedish academia perspective2012Ingår i: Quality Innovation Prosperity, ISSN 1335-1745, E-ISSN 1338-984X, Vol. 16, nr 2, s. 1-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of this article is to describe how Quality Management (QM) is perceived today by scholars at three Swedish universities, and into what QM is expected to develop into in twenty years. Data were collected through structured workshops using affinity diagrams with scholars teaching and performing research in the QM field. The results show that QM currently is perceived as consisting of a set of core of principles, methods and tools. The future outlook includes three possible development directions for QM are seen: [1] searching for a “discipline X” where QM can contribute while keeping its toolbox, [2] focus on a core based on the traditional quality technology toolbox with methods and tools, and [3] a risk that QM, as it is today, may seize to exist and be diffused into other disciplines.

  • 39.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Eriksson, Henrik
    Chalmers tekniska högskola, Teknikens ekonomi och organisation.
    Hallencreutz, Jacob
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle.
    Langstrand, Jostein
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Avdelningen för Kvalitetsteknik.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Zobel, Thomas
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Alive and kicking–but will Quality Management be around tomorrow?: A Swedish academia perspective2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose: There is a lack of a recognized conception of quality management (QM) comprises of, as well as a clear roadmap of where QM is heading. The purpose of this article is to investigate how QM is perceived today by scholars at three Swedish universities, but also how and into what QM is expected to develop into in twenty years.Methodology: Data have been collected through three structured workshops using affinity diagrams with scholars teaching and performing research in the QM field affiliated with three different Swedish universities.Findings: The results indicate that current QM is perceived similarly among the universities today, although the taxonomy differs slightly. QM is described as a fairly wide discipline consisting of a set of core of principles that in turn guide which methods and tools that currently by many are perceived as the core of the discipline. The outlook for the future differs more where three possible development directions for QM are seen: [1] searching for a “discipline X” where QM can contribute while keeping its toolbox, [2] focus on a core based on the traditional quality technology toolbox with methods and tools, and [3] a risk that QM, as it is today, may seize to exist and be diffused into other disciplines. Originality/value: This article contributes with a viewpoint on QM today and its future development from the academicians’ perspective.

  • 40.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Trafikverket.
    Control charts for assessment of linear asset condition using both temporal and spatial information2012Ingår i: Proceedings of the 2nd International Workshop & Congress on eMaintenance: Dec 12-14 Luleå, Sweden : eMaintenace: trends in technologies and methodologies, challenges, possibilities and applications / [ed] Ramin Karim; Aditya Parida; Uday Kumar, Luleå: Luleå tekniska universitet, 2012, s. 145-152Konferensbidrag (Refereegranskat)
  • 41.
    Kvarnström, Björn
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Improving traceability in continuous processes using flow simulations2012Ingår i: Production planning & control (Print), ISSN 0953-7287, E-ISSN 1366-5871, Vol. 23, nr 5, s. 396-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traceability is normally difficult to achieve in continuous processes, since there are no natural batch structures. In this article, we demonstrate flow-based simulation using process data to improve traceability in a continuous pelletising process. Using the simulation model, the engineers could test the impacts of process disturbances, identify cause and effect relations and aid control in case of process disturbances. In a field trial where the chemistry of an additive was varied during production of a special product, the simulation forecasts predicted the level of the chemical content after the plant within the errors that the engineers found acceptable.

  • 42.
    Chronéer, Diana
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Managerial complexity of R&D projects in process industry: a Swedish study2012Ingår i: Project Management Journal, ISSN 8756-9728, E-ISSN 1938-9507, Vol. 43, nr 2, s. 21-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Process industries often have features that differ from other businesses, such as round-the-clock production and costly and specialized production processes—features that have not been dealt with in the project management literature. We highlight and identify the complexity of R&D projects in the Swedish process industry and its interrelated process development and product development activities based on results from interviews and a case study. The different competence areas in which a project manager must integrate and manage R&D projects is illustrated. We conclude that a project manager needs both production and product-related competence, including customers' processes

  • 43.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Traceability in iron ore processing and transports2012Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 30, s. 44-51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ability to track and trace products in a production process and in the transportation chain from supplier to customers is important for quality control and process improvements. However, good traceability is often difficult achieve for continuous process products as well as for batch produced products where batches intermix. In this paper, guidelines for improving traceability and setting up a traceability system in the iron ore production process are presented based on two case studies. One case is using process data in a simulation approach for a pellets plant and the other is using RFID methodology to trace pellets in the distribution chain. Results show that simulations can aid short-term traceability, whereas long term traceability is possible through marking pellets with RFID transponders, where the applications are suitable.

  • 44.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vanhatalo, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle.
    Nordenvaad, Magnus Lundberg
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A Bayesian analysis of unreplicated two-level factorials using effects sparsity, hierarchy, and heredity2011Ingår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, nr 2, s. 152-166Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article proposes a Bayesian procedure to calculate posterior probabilities of active effects for unreplicated two-level factorials. The results from a literature survey are used to specify individual prior probabilities for the activity of effects and the posterior probabilities are then calculated in a three-step procedure where the principles of effects sparsity, hierarchy, and heredity are successively considered. We illustrate our approach by reanalyzing experiments found in the literature.

  • 45.
    Vanhatalo, Erik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Bergquist, Bjarne
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    A method to determine transition time for experiments in dynamic processes2011Ingår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, nr 1, s. 30-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Process dynamics is an important consideration during the planning phase of designed experiments in dynamic processes. After changes of experimental factors, dynamic processes undergo a transition time before reaching a new steady state. To minimize experimental time and reduce costs and for experimental design and analysis, knowledge about this transition time is important. In this article, we propose a method to analyze process dynamics and estimate the transition time by combining principal component analysis and transfer function-noise modeling or intervention analysis. We illustrate the method by estimating transition times for a planned experiment in an experimental blast furnace.

  • 46. Kvarnström, Björn
    et al.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Vännman, Kerstin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    RFID to improve traceability in continuous granular flows: an experimental case study2011Ingår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, nr 4, s. 343-357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traceability is important for identifying the root-causes of production related quality problems. Traceability can often be reached by adding identification markers on products, but this is not a solution when the value of the individual product is much lower than the incurred cost of a marking system. This is the case for continuous production of granular media. The use of Radio Frequency Identification (RFID) technique to achieve traceability in continuous granular flows has been proposed in the literature. We study through experiments different methods to improve the performance of such an RFID system. For example, larger transponders and multiple readers are shown to improve the RFID system performance.

  • 47.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Westerberg, Mats
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Testing for willingness to engage in improvement work2011Ingår i: Quality Innovation Knowledge: 10th International Research Conference on Quality, Innovation and Knowledge, Monash University , 2011Konferensbidrag (Refereegranskat)
  • 48.
    Bergquist, Bjarne
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Tracing granular products using RFID2011Konferensbidrag (Övrigt vetenskapligt)
  • 49.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Kvarnström, Björn
    Tracking and tracing products in continuous processes2011Ingår i: International Congress on Productivity, Quality, Reliability, Optimization and Modelling: ICPQROM 2011, Indian Statistical Institute , 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Traceability is important for quality control and process improvements, but it is often difficult to track or trace products in continuous process production, since products and product lots are difficult to separate. In the past, engineers have had to rely on coarse calculations for tracing products, but new possibilities emerge as new technology and models are being used. In this paper, we present experiences from applying chemical and RFID tracers to achieve traceability in continuous flows, with examples taken from the minerals processing sector.

  • 50.
    Abrahamsson, Lena
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Kaplan, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Johansson, Jan
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Rask, Kjell
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Fältholm, Ylva
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Arbetsvetenskap.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Bergquist, Bjarne
    Projekt: LUPO - globala länkar2010Övrigt (Övrig (populärvetenskap, debatt, mm))
12 1 - 50 av 92
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf