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  • 1.
    Abdul-Jalbar, Beatriz
    et al.
    Dpto. de Matemáticas, Estadística e Investigación Operativa, Universidad de La Laguna, Spain.
    Segerstedt, Anders
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    A note on “A new heuristic for one warehouse and N retailers problem” by Ercan Senyigit and Hakan Akkan in Procedia - Social and Behavioral Sciences, 62, p. 656 – 660, 20122019Manuskript (preprint) (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 2.
    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 länkar2010Annet (Annet (populærvitenskap, debatt, mm))
  • 3.
    Ahlkvist, Alvina
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Hur lyckas organisationer implementera ISO 9001?: Ett medarbetarperspektiv2021Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Genom att arbeta med kvalitetsledning kan en organisation ständigt förbättras och bibehålla konkurrenskraft. Ett sätt att arbeta med kvalitetsledning är genom implementering av kvalitetsledningsstandarden ISO 9001. Standarden nämner sju principer, varav en är medarbetarnas engagemang, vilket är essentiellt för organisationer för att lyckas med implementeringen av ISO 9001. Syftet med studien var att undersöka hur organisationer kan lyckas med att implementera ISO 9001 genom att undersöka vilka faktorer som bidrar till medarbetarnas engagemang och hur medarbetares engagemang kan stärkas.

    Litteraturstudier indikerar på flera faktorer som kan ha inverkan på medarbetares engagemang, vilka i sin tur beskrevs kunna påverkas med hjälp av förändringsledning. Med utgångspunkt i den teoretiska referensramen analyserades intervjuer, observationer och enkätundersökning med hjälp av tematisk och multivariat analys. På så sätt kartlades nuläget på fallföretaget. Tillsammans med resultatet från litteraturstudien framkom faktorer som kunde avgöra huruvida medarbetare engagerar sig i implementering av ISO 9001 eller inte.

     

    Av identifierade faktorer var det tre som kunde anses vara särskilt viktiga att hantera, då de antingen kan utgöra en barriär eller en framgångsfaktor för lyckad implementering. Faktorerna utgörs av Medvetenhet, Attityd, Användbarhet, Användarvänlighet och Ansvarskänsla, vilka har betydelse för att organisationer ska ta sig från sitt nuläge till sitt börläge. Nuläget utgör utgångspunkten för organisationen, och börläget representeras av en lyckad implementering: faktisk samt långsiktig användning av kvalitetsledningssystemet.

    Fulltekst (pdf)
    fulltext
  • 4. Ahmadi, Alireza
    et al.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Söderholm, Peter
    Risk of operational consequences of aircraft system failure2010Inngår i: International Journal of Performability Engineering, ISSN 0973-1318, Vol. 6, nr 2, s. 149-158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to describe a methodology for identifying different operational consequences and associated costs caused by aircraft system failure, in order to facilitate and enhance the capability of taking correct and efficient decisions when analyzing the cost-effectiveness of maintenance tasks. The paper focuses on the operational consequences of failures that lead to delay. To identify the operational consequences of aircraft system failures, Empirical studies of possible scenarios involving aircraft failures and their operational consequences for a commercial airline have been performed. Empirical data were extracted through document studies and interviews, guided by the application of an Event Tree Analysis (ETA). In order to effectively utilize the knowledge of field experts in the assessment process, a pairwise comparison technique was adopted for quantifying the contribution of different factors to the operational. The work was performed together with experienced practitioners from both an aircraft manufacturer and commercial airlines, which contributed to a continuous verification of the outcome of the study.The study shows that the proposed methodology based on ETA and pairwise comparison can be used to identify and quantify the cost of operational consequences of failures in aircraft operation, when there is no sufficient and reliable data.

  • 5.
    Ahmadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Soleimanmeigouni, Iman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Simulation of railway track geometry and intelligent maintenance planning: [Simulering av järnvägsspårgeometri och intelligent underhållsplanering]2021Rapport (Annet vitenskapelig)
    Abstract [en]

    Track is the fundamental part of railway infrastructure and represents a significant part of maintenance effort and cost. For example, in Sweden, the annual maintenance cost for only track geometry is between110 and 130 MSEK. The quality of the track, mostly, is represented by the track geometry properties. Track geometry degrades with age and usage; and loses its functionality over time. Poor quality of track geometry may result in safety problems, speed reduction, traffic disruption, greater maintenance cost, and higher degradation rate of the other railway components (e.g. rails, wheels, switches, and crossings). Railway track maintenance program development is challenging and requires appropriate modeling which reflects the real-life scenario and integrates influencing factors. In addition, there are several uncertainties in data collection, data analysis, modeling, and the prediction that are needed to be considered. Moreover, there is a lack of integrated platform that is able to access geometry data, extract associatedinformation, and retain this knowledge for supporting adaptive maintenance planning and scheduling. The above challenges necessitate the Infrastructure Manager (IM) to employ a maintenance management system that enables higher capacity for evaluation of track performance, learning from asset history, context-driven awareness, planning & scheduling, and transformation of this information to knowledge for decision making. The SIMTRACK project will facilitate simulation-based platform that enables development of a tools,methodologies and techniques for optimization of track geometry maintenance planning, scheduling andopportunistic maintenance. This will provide a basis to predict track geometry degradation, analyse therisk of failures and forecast the maintenance activities as well as renewal investment requirements. The results will enhance safety, maximize capacity utilization, and lead to an efficient and cost effective maintenance program. The project structure track is structured into 6 work packages. WP1 deals with the project management. WP2 presentsthe industrial scenarios, specifications and requirements that provide inputs to WP3 and WP4. WP3 andWP4 are defined as predictive modelling and analytics of track geometry condition and trackmaintenance optimization and decision support system respectively. WP5 is dedicated to evaluation ofabsolute track geometry condition. Finally, WP6 deals with dissemination and exploitation, is devotedfor formulating comprehensive plans for results assimilation by the partners and set the ground for theexploitation. Figure 1 shows the work packages and their relationships.

    Fulltekst (pdf)
    fulltext
  • 6.
    Ahmed, Kazi Pushpa
    et al.
    Institute of Business Administration, University of Dhaka, Bangladesh.
    Mourin, Adnin
    Information Systems, Linnaeus University, Sweden.
    Ahmed, Kazi Main Uddin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Application of Predictive Maintenance in Industry 4.0: A Use-Case Study for Datacenters2021Inngår i: 2021 3rd International Conference on Sustainable Technologies for Industry 4.0 (STI), IEEE, 2021Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the context of the upcoming 4th generation industrial revolution (industry 4.0), mechanical failures in the cyber-physical systems have huge financial impacts. The IT industry like Google, Facebook, Microsoft, etc. mostly depends on the Datacenters (DCs) to assure the quality of services. The equipment of the DC including the power supply system and the computational resources are sensitive to supplied power quality, thus predictive maintenance is needed to prevent failures and limit financial losses. The predictive maintenance assures operational security based on the monitored data that can characterize the failures of the physical machines, and also ensures the maximum return of the capital investment by prolonging the useful life of the equipment. The size of the monitored data typically occupies large memory space that can compare with “big-data” nowadays. Thus, the big-data-sized monitored data analysis is an additional computational challenge to characterize the failures of physical machines, hence, schedule the predictive maintenance. However, characterizing the failure and repair time of the major components based on the measured data is still a challenge that is the goal of this paper. Meanwhile, the revenue of the business also largely depends on the accuracy of predictive maintenance in general. In this paper, a predictive maintenance approach is presented based on the stochastic failure time of the major components of the DC. Additionally, the business challenges for predictive maintenance considering industry 4.0 are also analyzed in this paper.

  • 7.
    Ahmer, Muhammad
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement. AB SKF.
    Intelligent fault diagnosis and predictive maintenance for a bearing ring grinder2023Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Predicting the failure of any structure is a difficult task in a mechanical system. However complicated and difficult the prediction might be, the first step is to know the actual condition of the system. Given the complexity of any machine tool, where a number of subsystems of electro-mechanical structures interact to perform the machining operation, failure diagnostics become more challenging due to the high demand for performance and reliability. In a production environment, this results in maintenance costs that the management always strives to reduce. Condition-based machine maintenance (CBM) is considered to be the maintenance strategy that can lead to failure prediction and reducing the maintenance cost by knowing the actual condition of the asset and planning the maintenance activities in advance.

    Grinding machines and grinding processes have come a long way since the inception of the centuries old grinding technique. However, we still have a number of challenges to overcome before a completely monitored and controlled machine and process can be claimed. One such challenge is to achieve a machine level CBM and predictive maintenance (PdM) setup which is addressed in this thesis. A CBM implementation framework has been proposed which combines the information sampled from sensors installed for the purpose of the process as well as condition monitoring. Accessing the machine's controller information allows the data to be processed with respect to different machine states and process stages. The successful implementation is achieved through a real-time and synchronized data acquisition setup that allows data from multiple sources to be acquired, stored, and consolidated. The dataset thus generated is used in a significant part of this project and is also published in Swedish National Data Service (SND).

    The thesis also presents the failure diagnostic model based on two step classification approach using benchmarked random forest models. The binary classifier predicts if there is a fault present in the machine based on crucial sensors data from the Idle segment of the grinding cycle. Multi-class random forest classifier diagnosis the fault condition. PdM, knowing when to trigger maintenance action, is achieved through predicting the overall quality of the produced parts from the feature set extracted from sensor data of the Spark-out segment of the grinding cycle. Combining fault diagnosis with the predicted quality information resulted in reliable and actionable maintenance decisions for the bearing ring grinder. The demonstrated setup, based on a production bearing ring grinder, is adaptable to similar machines in production.

    Fulltekst (pdf)
    fulltext
  • 8.
    Ahmer, Muhammad
    et al.
    AB SKF, Gothenburg, Sweden.
    Marklund, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gustafsson, Martin
    AB SKF, Gothenburg, Sweden.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Integration of process monitoring and machine condition diagnostics to improve quality prediction in grinding2021Inngår i: 9th CIRP Conference on High Performance Cutting / [ed] Erdem Ozturk; David Curtis; Hassan Ghadbeigi, Elsevier, 2021, s. 170-173Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Bearing ring grinding incorporates sensors to control the grinding cycle in real time. Prediction of output quality is difficult due to the complex combination of process settings and machine characteristics. Causal relationship of machine performance with varying operating conditions was studied with reference to the produced quality by adding condition monitoring setup to the machine. Data driven diagnostics of machine condition through integration of condition and process monitoring sensor data at the completion of the grinding cycle improves quality cognisance. This can be used to tune control parameters to achieve more predictable quality in successive cycles.

  • 9.
    Ahmer, Muhammad
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement. AB SKF, Gothenburg, Sweden.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Marklund, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gustafsson, Martin
    AB SKF, Gothenburg, Sweden.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Dataset Concerning the Process Monitoring and Condition Monitoring Data of a Bearing Ring Grinder2022Dataset
    Abstract [en]

    In the manuscript, we have investigated the effective use of sensors in a bearing ring grinder for failure classification in the condition-based maintenance context. The proposed methodology combines domain knowledge of process monitoring and condition monitoring to successfully achieve failure mode prediction with high accuracy using only a few key sensors. This enables manufacturing equipment to take advantage of advanced data processing and machine learning techniques.

    The grinding machine is of type SGB55 from Lidköping Machine Tools and is used to produce functional raceway surface of inner rings of type SKF-6210 deep groove ball bearing. Additional sensors like vibration, acoustic emission, force, and temperature sensors are installed to monitor machine condition while producing bearing components under different operating conditions. Data is sampled from sensors as well as the machine's numerical controller during operation. Selected parts are measured for the produced quality.

  • 10.
    Ahmer, Muhammad
    et al.
    Manufacturing and Process Development, AB SKF, Gothenburg, Sweden.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Marklund, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gustafsson, Martin
    Manufacturing and Process Development, AB SKF, Gothenburg, Sweden.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Failure mode classification for condition-based maintenance in a bearing ring grinding machine2022Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 122, s. 1479-1495Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Technical failures in machines are major sources of unplanned downtime in any production and result in reduced efficiency and system reliability. Despite the well-established potential of Machine Learning techniques in condition-based maintenance (CBM), the lack of access to failure data in production machines has limited the development of a holistic approach to address machine-level CBM. This paper presents a practical approach for failure mode prediction using multiple sensors installed in a bearing ring grinder for process control as well as condition monitoring. Bearing rings are produced in a set of 7 experimental runs, including 5 frequently occurring production failures in the critical subsystems. An advanced data acquisition setup, implemented for CBM in the grinder, is used to capture information about each individual grinding cycle. The dataset is pre-processed and segmented into grinding cycle stages before time and frequency domain feature extraction. A sensor ranking algorithm is proposed to optimize feature selection for failure classification and the installation cost. Random forest models, benchmarked as best performing classifiers, are trained in a two-step classification framework. The presence of failure mode is predicted in the first step and the failure mode type is identified in the second step using the same feature set. Defining the feature set in the failure detection step improves the predictor generalization with the classifiers’ performance accuracy of 99%99% on the test dataset. The presented approach demonstrates an efficient failure mode classification by selecting crucial sensors resulting in a cost-effective CBM implementation in a bearing ring grinder.

  • 11.
    Ahmer, Muhammad
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement. Manufacturing and Process Development, AB SKF, 415 50 Gothenburg, Sweden.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Marklund, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Gustafsson, Martin
    Manufacturing and Process Development, AB SKF, 415 50 Gothenburg, Sweden.
    Berglund, Kim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Using Multivariate Quality Statistic for Maintenance Decision Support in a Bearing Ring Grinder2022Inngår i: Machines, E-ISSN 2075-1702, Vol. 10, nr 9, artikkel-id 794Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Grinding processes’ stochastic nature poses a challenge in predicting the quality of the resulting surfaces. Post-production measurements for form, surface roughness, and circumferential waviness are commonly performed due to infeasibility in measuring all quality parameters during the grinding operation. Therefore, it is challenging to diagnose the root cause of quality deviations in real-time resulting from variations in the machine’s operating condition. This paper introduces a novel approach to predict the overall quality of the individual parts. The grinder is equipped with sensors to implement condition-based maintenance and is induced with five frequently occurring failure conditions for the experimental test runs. The crucial quality parameters are measured for the produced parts. Fuzzy c-means (FCM) and Hotelling’s T-squared (T2) have been evaluated to generate quality labels from the multi-variate quality data. Benchmarked random forest regression models are trained using fault diagnosis feature set and quality labels. Quality labels from the T2 statistic of quality parameters are preferred over FCM approach for their repeatability. The model, trained from T2 labels achieves more than 94% accuracy when compared to the measured ring disposition. The predicted overall quality using the sensors’ feature set is compared against the threshold to reach a trustworthy maintenance decision.

  • 12. Akersten, Per-Anders
    et al.
    Klefsjö, Bengt
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Dependability management as a management system based on core values, methodologies and tools2001Inngår i: Safety and reliability: towards a safer world : proceedings of the European Conference and Reliability, ESRel 2001, Torino, Italy 16 - 20 September / [ed] Enrico Zio ; Micaela Demichela; Norberto Piccinini, Torino: Politecnica , 2001, s. 245-252Konferansepaper (Fagfellevurdert)
  • 13.
    Al Zagnonn, Mohammed
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Tillämpning av Partial Least Squares för analys och processövervakning av Hybrits reduktionsprocess2023Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Hybrit development AB är ett bolag som strävar mot att kunna producera fossilfritt stål genom att reducera järnmalmspellets med hjälp av vätgas. Därför har Hybrit utfört experimentella kampanjer där genomförbarheten av att reducera järnmalmspellets med hjälp av vätgas undersökts och studerats. Vid produktion av järn och stål måste produktkvalitén tas i beaktan. Reduktionsprocessen karaktäriseras av en mängd olika process- och kvalitetsparametrar, där kvalitetsparametrarna beskriver produktkvalitén. Det är av intresse att studera hur processparametrarna påverkar produktkvalitén. Processparametrarna kan mätas vid vilket tidpunkt som helst genom olika sensorer. Produktkvalitén kan bestämmas först efter att järnmalmspelletsen är färdigreducerad. Därför präglas processen av en tidsfördröjning mellan mätningen av processparametrarna och labanalysemätningarna av kvalitetsparametrarna. På grund av tidsfördröjningen är det av intresse att kunna prediktera produktkvalitén utifrån processparametrarna. Om det går att prediktera produktkvalitén, är det av vikt att kunna avgöra prediktionens giltighet. 

    Examensarbetets syfte är att identifiera hur reduktionsprocessparametrarna påverkar reducerade järnets kvalitetsparametrar. En processövervakningsmetod som passar för processövervakning ska testas och undersökas utifrån hur metoden kan användas för att avgöra prediktionens giltighet. Processövervakningen ska användas för att avgöra om processen befinner sig i ett processläge som bidrar till en någorlunda korrekt och lämplig prediktion av produktkvalitén. 

    För analys av data användes 65 processparametrar och 6 kvalitetsparametrar. Den multivariata analysmetoden Partial Least Squares (PLS) användes för att nå syftet med examensarbetet. Via PLS skapades en modell som kunde beskriva vilka processparametrar som påverkade kvalitetsparametrarna samt hur processparametrarna påverkade kvalitetsparametrarna. PLS-modellen kunde prediktera kvalitetsparametrarna någorlunda korrekt och lämpligt, givet att processen befinner sig inom ramen för modellen och att det är en hög förklaringsgrad för kvalitetsparametern som predikteras. Kvalitetsparametern Y6-1 predikterades sämre eftersom förklaringsgraden för Y6-1 var låg. Processövervakningsmetoden som testades och undersöktes var PLS-övervakning. För att undersöka hur PLS-övervakning kan användas för att avgöra prediktions giltighet, användes tre processövervakningsverktyg. Dessa var X-scores processövervakning, Hotelling T2 och SPE. Resultatet var att PLS-övervakning kunde angiva hur processen förhåller sig till modellen. Observationerna som avvek i PLS-övervakningen predikterades sämre. Därmed kunde information om prediktionens giltighet genom PLS-övervakning erhållas. Att tillämpa PLS-övervakning för att avgöra prediktionens giltighet är en större framgång. Detta på grund av att information om produktkvalitén innan reduktionsprocessen är genomförd kan användas för att säkerställa produktion med tillfredställande kvalitet. Att tillämpa multivariata processövervakningsmetoder för att övervaka de predikterade kvalitetsparametrarna kan vara av intresse för framtida studier. Detta då processövervakningen kan användas för att minimera den interna variationen hos kvalitetsparametrarna.

    Fulltekst (pdf)
    fulltext
  • 14.
    Aldenlöv, Jens
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle.
    Exploring Public Procurement of Swedish Railway Infrastructure Maintenance2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In 2002, Sweden started to outsource its railway infrastructure maintenance. Through gradual exposure (i.e. outsourcing one contract area at a time), the Swedish Transport Administration has developed its competence of being a client towards its contractors. The last contract was outsourced in 2014. In the last decade, the development of governance techniques and maintenance cost has not matched the increase in traffic. Due to an increased awareness in environmentally friendlier transportation, traffic is only expected to increase further in the coming years. Governance techniques and maintenance cost ultimately depends on the client-contractor relationship through public procurement. Hence, there is a need to understand public procurement of railway infrastructure maintenance. Therefore, the purpose of this thesis is to contribute to the knowledge of public procurement of railway infrastructure maintenance. Three separate studies were conducted. Study 1 was a literature review to explore and determine the state-of-the-art for the field of public procurement of railway maintenance. Study 2 was a linear regression analysis to examine the relationship between contract design and the output of maintenance in Sweden. Study 3 was an interview study in Sweden that explored what factors that supports or hinders collaboration in railway maintenance.

    The main results of these studies are that asset knowledge is important for both the client and the contractor. Through reliable asset knowledge, incentives and contracts can be designed to support governance and collaboration. Today, railway infrastructure maintenance is dominated by informal relationships that lack the support of formal partnering activities. When an informal relationship is supported by a formal structure it provides a basis for innovation. This formal structure should be centralized around gaining and sharing asset knowledge. By establishing such a system to increase the asset knowledge and supporting collaboration, public organizations of maintenance can provide a basis for the improvement of maintenance.

    Fulltekst (pdf)
    fulltext
  • 15.
    Aldenlöv, Jens
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, Industriell ekonomi.
    Public Procurement of Railway Infrastructure Maintenance:A Linear Regression Analysis2019Inngår i: Operations Adding Value to Society: 26th EurOMA Conference Proceedings / [ed] Kovács, Gyöngyi; Kuula, Markku, 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Swedish railway infrastructure maintenance has been outsourced through gradualexposure since 2002. The idea behind outsourcing was to reduce cost and improveefficiency. However, railway maintenance cost has increased faster than railwaymaintenance operations, resulting in neglected railway maintenance. Since railwayoperation is governed by the contract design the purpose of this paper was to explore therelationship between contract design and maintenance outcome within Swedish railwayinfrastructure maintenance. To explore this relationship linear regression analysis wasused. The result indicates that asset knowledge and accessibility to the track areimportant to consider for improving maintenance operations.

    Fulltekst (pdf)
    fulltext
  • 16.
    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 review2017Inngår 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. 10-21Konferansepaper (Fagfellevurdert)
    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.

  • 17.
    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 review2017Konferansepaper (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 18.
    Al-Douri, Yamur K.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Two-Level Multi-Objective Genetic Algorithm for Risk-Based Life Cycle Cost Analysis2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Artificial intelligence (AI) is one of the fields in science and engineering and encompasses a wide variety of subfields, ranging from general areas (learning and perception) to specific topics, such as mathematical theorems. AI and, specifically, multi-objective genetic algorithms (MOGAs) for risk-based life cycle cost (LCC) analysis should be performed to estimate the optimal replacement time of tunnel fan systems, with a view towards reducing the ownership cost and the risk cost and increasing company profitability from an economic point of view. MOGA can create systems that are capable of solving problems that AI and LCC analyses cannot accomplish alone.

    The purpose of this thesis is to develop a two-level MOGA method for optimizing the replacement time of reparable system. MOGA should be useful for machinery in general and specifically for reparable system. This objective will be achieved by developing a system that includes a smart combination of techniques by integrating MOGA to yield the optimized replacement time. Another measure to achieve this purpose is implementing MOGA in clustering and imputing missing data to obtain cost data, which could help to provide proper data to forecast cost data for optimization and to identify the optimal replacement time.

    In the first stage, a two-level MOGA is proposed to optimize clustering to reduce and impute missing cost data. Level one uses a MOGA based on fuzzy c-means to cluster cost data objects based on three main indices. The first is cluster centre outliers; the second is the compactness and separation ( ) of the data points and cluster centres; the third is the intensity of data points belonging to the derived clusters. Level two uses MOGA to impute the missing cost data by using a valid data period from that are reduced data in size. In the second stage, a two-level MOGA is proposed to optimize time series forecasting. Level one implements MOGA based on either an autoregressive integrated moving average (ARIMA) model or a dynamic regression (DR) model. Level two utilizes a MOGA based on different forecasting error rates to identify proper forecasting. These models are applied to simulated data for evaluation since there is no control of the influenced parameters in all of the real cost data. In the final stage, a two-level MOGA is employed to optimize risk-based LCC analysis to find the optimal replacement time for reparable system. Level one uses a MOGA based on a risk model to provide a variation of risk percentages, while level two uses a MOGA based on an LCC model to estimate the optimal reparable system replacement time.

    The results of the first stage show the best cluster centre optimization for data clustering with low  and high intensity. Three cluster centres were selected because these centres have a geometry that is suitable for the highest data reduction of 27%. The best optimized interval is used for imputing missing data. The results of the second stage show the drawbacks of time series forecasting using a MOGA based on the DR model. The MOGA based on the ARIMA model yields better forecasting results. The results of the final stage show the drawbacks of the MOGA based on a risk-based LCC model regarding its estimation. However, the risk-based LCC model offers the possibility of optimizing the replacement schedule.

    However, MOGA is highly promising for allowing optimization compared with other methods that were investigated in the present thesis.

    Fulltekst (pdf)
    fulltext
  • 19.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Al-Chalabi, Hussan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Time Series Forecasting using Genetic Algorithm: A Case Study of Maintenance Cost Data For Tunnel Fans2018Inngår i: ADVCOMP 2018: The Twelfth International Conference on Advanced Engineering Computing and Applications in Sciences / [ed] Claus-Peter Rückemann; Ahmad Rafi Qawasmeh, International Academy, Research and Industry Association (IARIA) , 2018, s. 4-9Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Time series forecasting is widely used as a basis for economic planning, production planning, production control and optimizing industrial processes. The aim of this study has been to develop a novel two-level Genetic Algorithm (GA) to optimize time series forecasting in order to forecast cost data for fans used in road tunnels by the Swedish Transport Administration (Trafikverket). The first level of the GA is responsible for the process of forecasting time series cost data, while the second level evaluates the forecasting. The first level implements GA based on the Autoregressive integrated moving average (ARIMA) model. The second level utilizes a GA based on forecasting error rate to identify a proper forecasting. The results show that GA based on the ARIMA model produces better forecasting results for the labor cost data objects. It was found that a multi-objective GA based on the ARIMA model showed an improved performance. The forecasted data can be used for Life cycle cost (LCC) analysis.

  • 20.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Hamodi, Hussan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Zhang, Liangwei
    Department of Industrial Engineering, School of Mechanical Engineering, Dongguan University of Technology, 523808 Dongguan, China.
    Data clustering and imputing using a two-level multi-objective genetic algorithms (GA): A case study of maintenance cost data for tunnel fans2018Inngår i: Cogent Engineering, E-ISSN 2331-1916, Vol. 5, nr 1, s. 1-16, artikkel-id 1513304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Data clustering captures natural structures in data consisting of a set of objects and groups similar data together. The derived clusters can be used for scale analysis and to posit missing data values in objects, as missing data have a negative effect on the computational validity of models. This study develops a new two-level multi-objective genetic algorithm (GA) to optimize clustering in order to redact and impute missing cost data for fans used in road tunnels by the Swedish Transport Administration (Trafikverket). The first level uses a multi-objective GA based on fuzzy c-means to cluster cost data objects based on three main indices. The first is cluster centre outliers; the second is the compactness and separation ( ) of the data points and cluster centres; the third is the intensity of data points belonging to the derived clusters. Our clustering model is validated using k-means clustering. The second level uses a multi-objective GA to impute the missing cost redacted data in size using a valid data period. The optimal population has a low , 0.1%, and a high intensity, 99%. It has three cluster centres, with the highest data reduction of 27%. These three cluster centres have a suitable geometry, so the cost data can be partitioned into relevant contents to be redacted for imputing. Our model show better clustering detection and evaluation compared with k-means. The amount of missing data for the two cost objects are: labour 57%, materials 81%. The second level shows highly correlated data (R-squared 0.99) after imputing the missing data objects. Therefore, multi-objective GA can cluster and impute data to derive complete data that can be used for better estimation of forecasting.

  • 21.
    Ali, Ahsan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Effect of temperature on early stage adhesion during TiAlN sliding against Inconel 718 and Stainless steel 316L: High temperature tribology2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    High-performance materials such as stainless steels and nickel based super alloys are widely used in demanding applications where high mechanical and thermal properties are required. The applications of super alloys are mainly found in jet engines, power plants and gas turbines demanding high fatigue strength, corrosion and oxidation resistance as well as wear resistant properties. In order to use them, they go through various machining processes such as milling, turning, cutting, polishing etc. until the final product is achieved. Modern manufacturing industries employs various machining tools and technologies to improve the machining process of heat resistant super alloys. However, there are still challenges which needs to be addressed. Among them, adhesive wear of the machining tools is one of the main wear mechanism during the tribological interaction of tool and workpiece, preventing them to achieve the desired quality and surface finish of the end product. Moreover, it damages the tool reducing its lifecycle and in return, increasing the production cost. Among the cutting tools tungsten carbide (WC/Co) tools coated with TiAlN coating due to their good high temperature performance are extensively used. Nonetheless, these coatings still face issue like adhesive wear, abrasion, oxidation at higher temperature damaging the tools and subsequent machining. Therefore, it is imperative to understand the initiation mechanism of adhesive wear during the tribological interaction of super alloys and coated cutting tool material.

    In this research work, the tribological response of two coatings deposited by physical vapour deposition (PVD), having the composition Ti60Al40N and Ti40Al60N have been studied against two super alloys material, i.e. Inconel 718 and stainless steel 316L. A high temperature SRV (Schwingung (Oscillating), Reibung (Friction), Verschleiß (Wear)) reciprocation friction and wear test set up was employed to investigate the friction behaviour, wear rate and dominant wear mechanisms. 

    For Ti60Al40N coating, the experimental results revealed that generally, friction increases in case of sliding against Inconel 718 up to 400 °C and drops at 760 °C. A high wear volume at room temperature and a decrease to a minimum at 760 °C has been observed for Inconel 718. On the other side, Stainless steel 316L (SS 316L) faces a continuous rise in friction coefficient with highest value at 760 °C during sliding against Ti60Al40N coating. Wear is highest at 400 °C for SS 316L pin. The worn surfaces shows that both workpiece materials experience increase in material transfer due to adhesive wear with rise in temperature. At 400 °C, adhesion is the primary wear mechanism for both workpiece materials. A further rise in temperature to 760 °C promotes the adhesive wear through oxides formation on both material surfaces. 

    Similarly, Ti40Al60N coating shows the same friction behaviour with change in average steady state friction values for both material of Inconel 718 and SS 316L. Both workpiece materials responds in a similar way to wear volume loss, i.e. lowest at room temperature and highest at 760 °C. For Inconel 718, transfer of coating constituents on to the Inconel 718 pin surface was detected and associated with coating rupture and peeling, exacerbating with rise in temperature. Adhesion, abrasion, and oxidation are primary wear mechanisms at 400 °C and 760 °C. For SS 316L, coating transfer only happen at 400 °C. No damage of coating at 40 °C, a complete damage at 400 °C, and formation of dense porous oxides layers at 760 °C have been noticed. At 400 °C, adhesion, abrasion, and chipping while at 760 °C, adhesion, three body abrasion, ploughing and oxidation are the main wear mechanisms.

    Fulltekst (pdf)
    fulltext
  • 22.
    Ali, Asma Mahdi
    et al.
    Civil Engineering Department, Engineering College, Mustansiriyah University, Baghdad, Iraq.
    Al-Taai, Salwa R.
    Civil Engineering Department, Engineering College, Mustansiriyah University, Baghdad, Iraq.
    Jaafar, Esraa Kamal
    Civil Engineering Department, Engineering College, Mustansiriyah University, Baghdad, Iraq.
    Al-Maliki, Hadi Naser Ghadhban
    Civil Engineering Department, Engineering College, Mustansiriyah University, Baghdad, Iraq.
    Madhloom, Huda M.
    Civil Engineering Department, Engineering College, Mustansiriyah University, Baghdad, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nonlinear Simulation Analysis of Mechanical Behaviour of Rubberized Concrete2022Inngår i: International Journal of GEOMATE, ISSN 2186-2982, Vol. 22, nr 90, s. 125-137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The main objective is to simulate the representation of rubber concrete with different percentages (0, 20, 40, 60, 80, 100%) of rubber using a finite element approach with ANSYS V.15 software to evaluate the behavior of concrete under the influence of mechanical force by using a standard cylinder to calculate its compressive strength, elasticity modulus and displacements for comparison with the previous experimental study, which showed a very close agreement of 5 to 12% when compared between them. The results showed that when the percentage of rubber increases, it leads to a decrease in the compressive strength, that is, its resistance, and an increase in the corresponding displacements and deformations that occur in them, as a result of the concentration of these stresses in the rubber limits. The results also showed that the meshing distribution of the analyzed elements by the ANSYS gave higher values of compressive strength and a decrease in the corresponding displacements when they were regular i.e. homogeneous compared to the irregular ones. Finally, through statistical analysis, it was found that the mean and arithmetic mean were acceptable and close when comparing the theoretical and practical results.

    Fulltekst (pdf)
    fulltext
  • 23.
    Al-Kahwati, Kammal
    et al.
    Predge AB, Västra Varvsgatan 11, 97236 Luleå, Sweden.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system. Predge AB, Västra Varvsgatan 11, 97236 Luleå, Sweden.
    Flygel Nilsfors, Evert
    LKAB Norge AS, Bolagsgata 40, 8514 Narvik, Norway.
    Nilsen, Rune
    LKAB Norge AS, Bolagsgata 40, 8514 Narvik, Norway.
    Experiences of a Digital Twin Based Predictive Maintenance Solution for Belt Conveyor Systems2022Inngår i: PHME 2022: Proceedings of the 7th European Conference of the Prognostics and Health Management Society 2022 / [ed] Phuc Do; Gabriel Michau; Cordelia Ezhilarasu, PHM Society , 2022, s. 1-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Availability of belt conveyor systems is essential in production and logistic lines to safeguard production and delivery targets to customers. In this paper, experiences from commissioning, validation, and operation of an interactive predictive maintenance solution are reported. The solution and its development is formerly presented in Al-Kahwati et.al. (Al-Kahwati, Saari, Birk, & Atta, 2021), where the principles to derive a digital twin of a typical belt conveyor system comprising component-level degradation models, estimation schemes for the remaining useful life and the degradation rate, and vision-based hazardous object detection.

    Furthermore, the validation approach of modifying the belt conveyor and thus exploiting the idler misalignment load (IML) for the degradation predictions for individual components (including long-lasting ones) together with the actionable insights for the decision support is presented and assessed. Moreover, the approach to testing and validation of the object detection and its performance is assessed and presented in the same manner. An overall system assessment is then given and concludes the paper together with lessons learned.

    As pilot site for the study a belt conveyor system at LKAB Narvik in northern Norway is used.

  • 24.
    Almimi, Ashraf A.
    et al.
    NASA Langley Research Center, Hampton.
    Kulahci, Murat
    Informatics and Mathematical Modeling, Technical University of Denmark, Lyngby.
    Montgomery, Douglas C.
    Division of Mathematical and Natural Sciences, Arizona State University, Department of Industrial, Systems and Operations Engineering Arizona State University.
    Checking the adequacy of fit of models from split-plot designs2009Inngår i: Journal of QualityTechnology, ISSN 0022-4065, Vol. 41, nr 3, s. 272-284Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the main features that distinguish split-plot experiments from other experiments is that they involve two types of experimental errors: the whole-plot (WP) error and the subplot (SP) error. Taking this into consideration is very important when computing measures of adequacy of fit for split-plot models. In this article, we propose the computation of two R2, R 2-adjusted, prediction error sums of squares (PRESS), and R 2 -prediction statistics to measure the adequacy of fit for the WP and the SP submodels in a split-plot design. This is complemented with the graphical analysis of the two types of errors to check for any violation of the underlying assumptions and the adequacy of fit of split-plot models. Using examples, we show how computing two measures of model adequacy of fit for each split-plot design model is appropriate and useful as they reveal whether the correct WP and SP effects have been included in the model and describe the predictive performance of each group of effects.

  • 25.
    Almimi, Ashraf A.
    et al.
    NASA Langley Research Center, Hampton.
    Kulahci, Murat
    Arizona State University, Tempe.
    Montgomery, Douglas C.
    Division of Mathematical and Natural Sciences, Arizona State University, Arizona State University, Tempe.
    Follow-up designs to resolve confounding in split-plot experiments2008Inngår i: Journal of QualityTechnology, ISSN 0022-4065, Vol. 40, nr 2, s. 154-166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Split-plot designs are effective in industry due to time and/or cost constraints, restriction on randomization of the treatment combinations of the hard-to-change factors, and different sizes of experimental units. Some of the results of fractional factorial split-plot experiments can be ambiguous and a need may arise to conduct follow-up experiments to separate effects of potential interest by breaking their alias links with others. For completely randomized fractional factorial experiments, methods have been developed to construct follow-up experiments. In this article, we extend the foldover technique to break the alias chains of split-plot experiments. Because it is impractical or not economically possible to foldover the whole-plot factors, as their levels are often hard or expensive to change, the focus of this article is on folding over only one or more subplot factors in order to de-alias certain effects. Six rules are provided to develop foldovers for minimum aberration resolution III and resolution IV fractional factorial split-plot designs.

  • 26.
    Anandika, Rayendra
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stenström, Christer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ultrasonic phased array measurement of near-surface cracks in the railhead.2019Inngår i: World Congress on Railway Research (WCRR) 2019, Tokyo, Japan, Railway Technical Research Institute (RTRI, Japan) , 2019, artikkel-id PB027753Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Ultrasonic measurement is one of the non-destructive techniques used to inspect defects in the rail body. Ultrasonic measurement is known inappropriate to inspect near-surface defects because of a challenge, called dead-zone. It is signal noise or ringing phenomenon located at near-field in front of the transducer when measuring a material. Due to this, there is difficulty in analysing any measurement signal at this zone, including signals from near-surface defects. In this study, the dead zone was eliminated by attaching wedge to shift the location of noise signals relative to the near-surface defect locations. First, a known-depth defect was measured by using phased array ultrasonic testing (PAUT) to calibrate the ultrasonic equipment and found the best signal gain to eliminate diffuse scattering from defects. Second, a cracked spot on railhead was inspected at the right and left direction of the spot. After the measurement, the inspected spot was sliced into 0.65 mm-thick pieces. From those pieces, the actual crack depth could be observed directly. Based on those sliced pieces, the ultrasonic measurement results were verified. From this study, PAUT delivered accurate measurement result of 3.51-mm crack tip depth with an absolute error of 0.8% - 18%. This accurate result indicates that PAUT can be an alternative to inspect the near-surface crack in railhead. 

    Fulltekst (pdf)
    Ultrasonic phased array measurement of near-surface cracks in the railhead
  • 27.
    Andersen, Emil B.
    et al.
    Technical University of Denmark, Department of Chemical and Biochemical Engineering, Process and Systems Engineering Center (PROSYS), Building 229, 2800 Kongens Lyngby, Denmark.
    Udugama, Isuru A.
    Technical University of Denmark, Department of Chemical and Biochemical Engineering, Process and Systems Engineering Center (PROSYS), Building 229, 2800 Kongens Lyngby, Denmark.
    Gernaey, Krist V.
    Technical University of Denmark, Department of Chemical and Biochemical Engineering, Process and Systems Engineering Center (PROSYS), Building 229, 2800 Kongens Lyngby, Denmark.
    Bayer, Cristoph
    TH Nurnberg, Department of Process Engineering, Wassertorstraβe 10, 90489 Nurnberg, Germany.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi. Technical University of Denmark, DTU Compute, Richard Petersens Plads 324, 2800 Kongens Lyngby, Denmark.
    Big Data Generation for Time Dependent Processes: The Tennessee Eastman Process for Generating Large Quantities of Process Data2020Inngår i: 30th European Symposium on Computer Aided Process Engineering: Part A / [ed] Sauro Pierucci; Flavio Manenti; Giulia Luisa Bozzano; Davide Manca, Elsevier, 2020, s. 1309-1314Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The concept of applying data-driven process monitoring and control techniques on industrial chemical processes is well established. With concepts such as Industry 4.0, Big Data and the Internet of Things receiving attention in industrial chemical production, there is a renewed focus on data-driven process monitoring and control in chemical production applications. However, there are significant barriers that must be overcome in obtaining sufficiently large and reliable plant and process data from industrial chemical processes for the development of data-driven process monitoring and control concepts, specifically in obtaining plant and process data that are required to develop and test data driven process monitoring and control tools without investing significant efforts in acquiring, treating and interpreting the data. In this manuscript a big data generation tool is presented that is based on the Tennessee Eastman Process (TEP) simulation benchmark, which has been specifically designed to generate massive amounts of process data without spending significant effort in setting up. The tool can be configured to carry out a large number of data generation runs both using a graphical user interface (GUI) and through a.CSV file. The output from the tool is a file containing process data for all runs as well as process faults (deviations) that have been activated. This tool enables users to generate massive amounts of data for testing applicability of big data concepts in the realm of process control for continuously operating time dependent processes. The tool is available for all researchers and other parties who are interested.

  • 28.
    Andersen, Emil B.
    et al.
    Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark.
    Udugama, Isuru A.
    Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark.
    Gernaey, Krist V.
    Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark.
    Khan, Abdul R.
    Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark.
    Bayer, Christoph
    Department of Process Engineering, TH Nuernberg, Nuernberg, Germany.
    Kulahci, Murat
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle, Industriell ekonomi. Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark.
    An easy to use GUI for simulating big data using Tennessee Eastman process2022Inngår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 38, nr 1, s. 264-282Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Data-driven process monitoring and control techniques and their application to industrial chemical processes are gaining popularity due to the current focus on Industry 4.0, digitalization and the Internet of Things. However, for the development of such techniques, there are significant barriers that must be overcome in obtaining sufficiently large and reliable datasets. As a result, the use of real plant and process data in developing and testing data-driven process monitoring and control tools can be difficult without investing significant efforts in acquiring, treating, and interpreting the data. Therefore, researchers need a tool that effortlessly generates large amounts of realistic and reliable process data without the requirement for additional data treatment or interpretation. In this work, we propose a data generation platform based on the Tennessee Eastman Process simulation benchmark. A graphical user interface (GUI) developed in MATLAB Simulink is presented that enables users to generate massive amounts of data for testing applicability of big data concepts in the realm of process control for continuous time-dependent processes. An R-Shiny app that interacts with the data generation tool is also presented for illustration purposes. The app can visualize the results generated by the Tennessee Eastman Process and can carry out a standard fault detection and diagnosis studies based on PCA. The data generator GUI is available free of charge for research purposes at https://github.com/dtuprodana/TEP. 

  • 29.
    Andreasson, Emil
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Åhman, Pontus
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Improving Availability of the Pelletization Process2022Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Grate-Kiln-Cooler process is a commonly used method of sintering during iron ore pelletization, where the pellets are formed, dried, and hardened. The pellets are oxidized in the rotating Kiln, turning magnetite (Fe3O4) to hematite (Fe2O3), making the pellets attain suitable metallurgical attributes for further processing. The process is constantly exposed to thermal and mechanical stress, causing equipment degradation and thus unwanted production stops due to internal process disturbances. A suitable maintenance policy is required to cope with the risk of equipment degradation causing these production stops. Predictive maintenance (PdM) is the most current maintenance policy, utilizing a substantial amount of production data to foresee breakdowns and thus indicating the need for maintenance efforts to prevent them from occurring.          

    The global supplier of iron ore products, Loussavaara-Kiirunavaara Aktiebolag (LKAB), operates three pelletization plants in Kiruna. One of these pelletization plants experiences availability below desired levels. This hampers the plant from fulfilling its yearly production goals, resulting in lost revenue. This master's thesis aimed to increase the understanding of which causes influence the Grate-Kiln-Cooler process' availability. When these causes were identified, the aim was to develop a method of monitoring these to predict the need for maintenance (i.e., incorporating a PdM policy) to mitigate the risk of production stops. The work has been conducted by utilizing the systematic problem-solving DMAIC methodology.   

    The refractory material was identified as the primary contributor to the low availability in the investigated plant. Using principal component analysis (PCA) and statistical process control (SPC), a Hotelling T2 chart based on principal components was established to monitor the refractory material's condition. In this context, the combined usage of PCA and SPC highlighted three possible tendencies in the Kiln that potentially damaged the refractory material, causing production stops. The observed tendencies with the possibility of damaging the refractory material were; abnormally high refractory material temperatures, periods where the pellets' temperature exceeded the refractory material's temperature, and sporadic heat fluctuations in the refractory material. 

    The utilized Hotelling T2 chart provided a current state evaluation of the refractory material's condition and thus indicated the need for maintenance efforts. However, it was impossible to predict breakdowns by identifying patterns in either the T2-statistics or the individual charts. The inability to predict stops was derived from obstacles related to lacking documentation, deficient data, and that the time for breakdown is difficult to determine accurately. These obstacles hinder the prediction of breakdowns and, therefore, need to be dealt with to facilitate the implementation of a successful PdM strategy.

    Fulltekst (pdf)
    fulltext
  • 30.
    Arias Chao, Manuel
    et al.
    Chair of Intelligent Maintenance Systems, ETH Zürich, 8093 Zürich, Switzerland.
    Kulkarni, Chetan
    KBR, Inc., NASA Ames Research Center, Mountain View, CA 94035, USA.
    Goebel, Kai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik. PARC, Intelligent Systems Lab, Palo Alto, CA 94043, USA.
    Fink, Olga
    Chair of Intelligent Maintenance Systems, ETH Zürich, 8093 Zürich, Switzerland.
    Aircraft Engine Run-to-Failure Dataset under Real Flight Conditions for Prognostics and Diagnostics2021Inngår i: Data, E-ISSN 2306-5729, Vol. 6, nr 1, s. 5-5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A key enabler of intelligent maintenance systems is the ability to predict the remaining useful lifetime (RUL) of its components, i.e., prognostics. The development of data-driven prognostics models requires datasets with run-to-failure trajectories. However, large representative run-to-failure datasets are often unavailable in real applications because failures are rare in many safety-critical systems. To foster the development of prognostics methods, we develop a new realistic dataset of run-to-failure trajectories for a fleet of aircraft engines under real flight conditions. The dataset was generated with the Commercial Modular Aero-Propulsion System Simulation (CMAPSS) model developed at NASA. The damage propagation modelling used in this dataset builds on the modelling strategy from previous work and incorporates two new levels of fidelity. First, it considers real flight conditions as recorded on board of a commercial jet. Second, it extends the degradation modelling by relating the degradation process to its operation history. This dataset also provides the health, respectively, fault class. Therefore, besides its applicability to prognostics problems, the dataset can be used for fault diagnostics. 

  • 31.
    Arias Chao, Manuel
    et al.
    Chair of Intelligent Maintenance Systems, ETH Zurich, Switzerland.
    Kulkarni, Chetan
    KBR, Inc., NASA Ames Research Center, USA.
    Goebel, Kai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Fink, Olga
    Chair of Intelligent Maintenance Systems, ETH Zurich, Switzerland.
    Fusing physics-based and deep learning models for prognostics2022Inngår i: Reliability Engineering & System Safety, ISSN 0951-8320, E-ISSN 1879-0836, Vol. 217, artikkel-id 107961Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Physics-based and data-driven models for remaining useful lifetime (RUL) prediction typically suffer from two major challenges that limit their applicability to complex real-world domains: (1) the incompleteness of physics-based models and (2) the limited representativeness of the training dataset for data-driven models. Combining the advantages of these two approaches while overcoming some of their limitations, we propose a novel hybrid framework for fusing the information from physics-based performance models with deep learning algorithms for prognostics of complex safety-critical systems. In the proposed framework, we use physics-based performance models to infer unobservable model parameters related to a system’s components health by solving a calibration problem. These parameters are subsequently combined with sensor readings and used as input to a deep neural network, thereby generating a data-driven prognostics model with physics-augmented features. The performance of the hybrid framework is evaluated on an extensive case study comprising run-to-failure degradation trajectories from a fleet of nine turbofan engines under real flight conditions. The experimental results show that the hybrid framework outperforms purely data-driven approaches by extending the prediction horizon by nearly 127%. Furthermore, it requires less training data and is less sensitive to the limited representativeness of the dataset as compared to purely data-driven approaches. Furthermore, we demonstrated the feasibility of the proposed framework on the original CMAPSS dataset, thereby confirming its superior performance.

  • 32.
    Arranz, Miguel Castano
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, RaminLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Proceedings of the 5th International Workshop and Congress on eMaintenance: eMaintenance: Trends in Technologies & methodologies, challenges, possibilites and applications2019Konferanseproceedings (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 33.
    Arvidson, Rasmus
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Genberg, Albin
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    Reducing non-value-added time in virtual meetings: A case study at Lynk & Co2022Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Covid-19 pandemic resulted in organizations rapidly shifting from physical- to virtual meetings to keep their business going. However, with this came challenges and efficiency problems that organizations were not aware of. This master thesis focuses on identifying and finding potential solutions to reduce non-value-added time in virtual meetings. This was accomplished by studying Lynk & Co, a rapidly growing startup. Data was collected via a company-wide survey. The data was quantitatively analyzed using both univariate, bivariate, and multivariate methods as well as qualitatively analyzed using a thematic analysis approach. The quantitative results showed that 35,2% of the total Hours in meetings per day are hours wasted, this translates to 16% wasted hours per 8 hour work day. Additionally, the quantitative results showed that five independent variables affect the Wasted hours in virtual meetings per day. These were Hours in meetings per day, Key persons not attending the meeting, The meeting could have been replaced with an email,  Focusing on the meeting (I.e., not multitasking), and Being active in the discussions during the meeting. The qualitative results showed that the majority of the respondents highlighted either the same or similar problems and solutions regarding the virtual meeting inefficiencies. These were lack of agendas and insufficient meeting follow-ups. This concludes that the major root cause of the wasted time in virtual meetings was found to be inadequate meeting information combined with inadequate information regarding the work responsibilities of the employees. This resulted in two main recommendations for reducing non-value-added time in virtual meetings in a rapidly growing startup. These are (1) developing an internal meeting policy and (2) incorporating more detailed employee information in the virtual meeting communication software.

    Fulltekst (pdf)
    fulltext
  • 34.
    Asif, Muhammad
    et al.
    School of Management and Governance, University of Twente, Enschede, the Netherlands; Institute of Quality and Technology Management, University of the Punjab, Lahore, Pakistan.
    Searcy, Cory
    Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada.
    Garvare, Rickard
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Ahmad, Niaz
    National Textile University, Faisalabad, Pakistan.
    Including sustainability in business excellence models2011Inngår i: Total Quality Management and Business Excellence, ISSN 1478-3363, E-ISSN 1478-3371, Vol. 22, nr 7, s. 773-786Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to explore the adequacy of business excellence models (BEMs) to address corporate sustainability, which is conceptualised in terms of economic, social, and environmental bottom lines. How organisations may manage corporate sustainability in the absence of a comprehensive sustainability management system standard is also explored. A survey of literature has been carried out. The European Foundation for Quality Management (EFQM) excellence model and the Baldrige Criteria for Performance Excellence (BCPE) are analysed with regard to their considerations of sustainability. The findings reveal that while triple bottom-line considerations are addressed to some extent in the studied BEMs, the models per se do not comprehensively address sustainability issues and economic prosperity remains a dominant consideration. Suggestions for the improvement of the EFQM excellence model and BCPE are discussed. To provide a comprehensive approach for addressing corporate sustainability, an integrated quality-sustainability framework is proposed. The essence of the framework is that sustainability indicators, such as those provided in the Global Reporting Initiative framework, could be integrated with core business processes using the structures and infrastructure provided by BEMs. The proposed improvements should be considered in future revisions of the EFQM excellence model and BCPE.

  • 35.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    A project perspective on doctoral studies: a student point of view2017Inngår i: International Journal of Educational Management, ISSN 0951-354X, E-ISSN 1758-6518, Vol. 31, nr 7, s. 908-921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose

    Many doctoral students never obtain a doctoral degree, and many do not finish their studies in time. To promote aspects of effectiveness and efficiency in doctoral studies this article aims to explore a project perspective, more specifically how doctoral students experience their studies in terms of key dimensions of projects.

    Design/methodology/approach

    Written reflections concerning a project perspective in doctoral studies, based on 18 students at a Swedish university, have been categorised and analysed by means of the qualitative research software NVivo.

    Findings

    Main findings are: Reflections on the project manager role including both the supervisor and the doctoral student, and different views on project control parameters and the concepts goal-seeking and goal-orientation. A more comprehensive picture of project planning is presented, compared with the Individual Study Plan (ISP), including different project methods and tools that can be suitable in a doctoral project.

    Research limitations/implications

    The study is based on a limited number of doctoral students, however the aim has been to give examples of project perspectives. The findings could be valuable for increased understanding of doctoral studies and of the project management field in general.

    Practical implications

    The study can induce awareness among doctoral students and supervisors of a project perspective in doctoral studies, promoting aspects of efficiency and effectiveness.

    Originality/value

    Compared to previous research, this study explicitly tries to understand how doctoral students make sense of their doctoral studies from a project perspective.

  • 36.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Conclusions of planning and preparation for RCM implementation: a case study at a Swedish hydro power plant2002Inngår i: Proceedings: ICOMS-2002, International Conference of Maintenance Societies : Queensland Hilton Hotel, 21 - 24 May 2002, Brisbane, Queensland, Central Queensland University, 23 - 24 May 2002, Gladstone, Queensland, Brisbane, 2002Konferansepaper (Fagfellevurdert)
  • 37.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Managing the introduction of RCM experiences from a Swedish hydropower company2005Inngår i: 2005 IEEE Power Engineering Society general meeting: San Francisco, CA, June 12 - 16, 2005, Piscataway, NJ: IEEE Communications Society, 2005, s. 2646-2648Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The introduction of reliability centred maintenance, RCM, has become more and more commonly within different industrial sectors. The many application areas, and the long-time use of RCM, points to the importance and usefulness of RCM when developing an effective and efficient maintenance programme. However, introducing RCM, implies introducing a new way of way of working with maintenance in an organisation, which can be very complex and cumbersome. Although RCM is an organised common sense approach to improvements of maintenance performance, a long-term approach may be difficult to manage. Several examples of failed introductions of RCM exist in various lines of business and types of organisations. Some of the main reasons why the RCM introduction becomes problematic or fails are technical in nature, but the majority of problems seem to be managerial and organisational. The introduction characteristics described above has been studied within a longitudinal single-case study, performed within a hydropower organisation. The case study, as well a multiple-case study, including three other hydropower organisations. Based on the findings in the case studies, a comprehensive and holistic RCM introduction strategy was proposed. The strategy framework could be seen as a structured approach to managing obstacles and driving forces identified in the case studies.

  • 38.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Managing the introduction of reliability-centred maintenance, RCM: RCM as a method of working within hydropower organisations2003Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Due to a competitive environment, many companies are required to reduce their overall costs while maintaining the value and reliability of their assets. The use of Reliability-Centred Maintenance, RCM, can support organisations to develop an effective and efficient maintenance programme, meeting these requirements in a cost-effective manner. RCM basically combines different techniques and tools, in a systematic approach to managing risks, as a basis for maintenance decisions. When introducing RCM with the aim of changing the overall way of working with maintenance in the organisation, i.e. on a full-scale basis, a long- term introduction approach should preferably be used. In addition to improve the performance of the assets, this approach uses RCM to improve knowledge, motivation and teamwork among the personnel. In that way, the approach could promote commitment of managers and employees, making an RCM based maintenance programme far more likely to endure. However, in several cases, organisations have experienced severe difficulties when introducing RCM on full-scale basis. Some of the reasons are technical in nature, but the majority are managerial obstacles. In the research project presented in this thesis, an aim has been to obtain a better understanding of why some organisations experience a cumbersome introduction of RCM. A focus has been to identify managerial factors that affect an RCM introduction in form of obstacles and driving forces. In the research project, a longitudinal single-case study has been performed during 1997 - 2003, studying the efforts towards an RCM introduction in a Swedish hydropower company. Many of the findings in the single-case study have been validated by a multiple-case study, including three other hydropower organisations introducing RCM. The findings are basically different kinds of managerial factors. These factors could be managed within four management perspectives, which points out the need of a holistic approach when managing RCM introduction. An RCM introduction process has also been identified during the research, where the managerial factors can be structured according to different phases. Based on these findings, an RCM introduction strategy framework has been developed, with the aim to facilitate for organisations going to introduce RCM. The strategy framework is structured according to the different phases in the RCM introduction process, with requirements and recommendations to be considered in each phase.

    Fulltekst (pdf)
    FULLTEXT01
  • 39.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Reliability-centred maintenance: identification of management and organisational aspects when introducing RCM1999Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Increased demands on productivity, quality and cost-efficiency affecting manufacturing trends towards increased complexity and higher degree of process automation. A major break down in such a manufacturing system may generate severe damage on productivity, environment and personnel. Using risk assessment to identify serve risks within a plant, in combination with different maintenance strategies, is one course of action to prioritising maintenance activities needed. A methodology for executing a so-called risk-based maintenance is reliability-centred maintenance, RCM. There are several benefits generated from RCM, for example, improved safety and maintenance cost-effectiveness. Though, several companies have problems to make it work. The problems that occur are many times within management and organisational (M&O) aspects, such as lack of communication and management support. Some M&O aspects of importance when introducing improvement methods as TQM and TPM are similar with the ones valid for RCM. Though, differences seem to depend on the use of RCM in a more technology environment, overshadow the affects M&O aspects really bring about when introducing it. That is probably the main reason why obstacles occur when introducing RCM. A structured step model has been developed, focusing on the preparation and planning activities when introducing RCM.

    Fulltekst (pdf)
    FULLTEXT01
  • 40.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Will a preparation stage facilitate the implementation of RCM?1999Inngår i: Safety and Reliability: proceedings of ESREL '99 - The tenth European Conference on Safety and Reliability, [held in] Munich-Garching, Germany, 13-17 September 1999 / [ed] Gerhart I. Schueller; P. Kafka, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1999, s. 173-178Konferansepaper (Fagfellevurdert)
  • 41.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Akersten, Per-Anders
    RCM introduction: process and requirements management aspects2003Inngår i: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 9, nr 3, s. 250-264Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organisations have introduced reliability-centred maintenance (RCM) with a view to changing their overall way of performing maintenance. Many times, however, these organisations have experienced cumbersome or even failed RCM introduction. This is usually because of managerial and organisational obstacles, which more or less unexpectedly turn up during introduction. This paper focuses on managing the introduction of RCM. By applying process and requirement management principles, obstacles that turn up during introduction can be identified early on. As an example of this, we cite the results of a case study of the introduction of RCM in a Swedish hydropower company.

  • 42.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Chroneer, Diana
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Sundqvist, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Project Management Maturity Models – A Critical Review: A Case Study within Swedish Engineering and Construction Organizations2014Inngår i: Procedia - Social and Behavioral Sciences, ISSN 1877-0428, E-ISSN 1877-0428, Vol. 119, s. 837-846Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Different kinds of project management maturity models (PM3s) exist today, most of them inspired by the capability maturity model (CMM) developed in the beginning of the 90ies, originally intended to measure capability in software development projects. Research indicates that organizations with higher project management (PM) maturity levels are expected to be successful in terms of project effectiveness and efficiency, and thus have a competitive advantage in the marketplace. Though, despite several PM3s developed during a time period of over 20 years, knowledge about how PM3s are a*pplied in organizations is sparse within the PM literature. This paper explores how major engineering and construction companies view PM maturity and PM3s in order to develop and improve their PM practices. These kinds of organizations are mainly project-intensive, objective oriented,and have the capabilities to perform overall business development initiatives, i.e. suitable for applying PM3s.The contribution of PM3s to organizational improvement and development is somewhat unclear. Therefore, a literature review highlights different aspects regarding PM3s, specifically their purpose, strengths, and weaknesses. To what extent PM3s are used, interviews have been conducted with seven respondents within different project intensive organizations, in their roles as project managers or in charge of PM development. How a PM3 can beintroduced and applied is explored via an in-depth case study at the major mining company in Sweden, LKAB. However, tentative results show that the application of PM3s in Swedish engineering and construction organizations are limited, indicating that further research is needed

  • 43.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Chronéer, Diana
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Sundqvist, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Maturity assessment: towards continuous improvements for project-based organisations?2015Inngår i: International Journal of Managing Projects in Business/Emerald, ISSN 1753-8378, E-ISSN 1753-8386, Vol. 8, nr 2, s. 256-278Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PurposeThe aim of this study is to contribute to the empirical research on project management maturity assessments, specifically based on a maturity model. Design/methodology/approachThe empirical data is based on a case study including in-depth interviews with a semi-structured approach, followed by a focus group interview. A survey was distributed within a project-based organisation and to client and stakeholder representatives, and then analysed. The organisation in the case study is a project department within a Swedish mining company. FindingsCareful considerations are needed when choosing a project management maturity model (PM3) as the model structure can influence the assessment’s focus. It is also important to include both internal and external project stakeholders in the assessment to achieve an efficiency and effectiveness perspective when analysing PM capabilities. Valid information from an assessment is crucial, therefore, clear communication from management is important in order to motivate the participants in the assessment. Research limitations/implicationsImproved understanding for implementing and applying a PM3 contributes to the increased knowledge of drivers, enablers and obstacles when assessing PM maturity, which also creates a basis for further research initiatives. Practical implicationsAn increased knowledge of drivers, enablers and obstacles should be valuable for practitioners introducing and applying a PM3.Originality/valueThis case study gives an in-depth insight into the implementation of a PM3 within a project-based organisation. Through conducting a literature review, it was found that this type of empirical research is rare

  • 44.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Hannu, J.
    Luleå tekniska universitet.
    Can we make maintenance decisions on risk analysis results?2002Inngår i: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 8, nr 1, s. 77-91Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For several branches of industry, an increasingly competitive environment has raised important questions concerning maintenance in plant systems. For example, the 1996 deregulation in Sweden's electricity sector has resulted in increased competition among the country's power producers. To survive the competition, suppliers have to reduce maintenance costs, i.e. handle maintenance more efficiently. Risk analysis is one tool decision makers can use to help them prioritise as they plan maintenance actions. There are a number of different approaches to risk analysis. As the results of an analysis must form a reliable basis for decision making, it is important to consider whether the quality of the results will vary significantly with the risk analysis approach chosen. This paper presents a comparative study based on three independent risk analyses performed on a specific hydro-power plant. The comparison and evaluation of the analyses reveal major differences in performance and results, along with various factors that affect the quality of the analyses. The study establishes the importance of a well-planned requirement specification and the need to analyse and interpret risk analysis results, before making maintenance decisions.

  • 45.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Holmberg, Rikard
    Vattenfall Vattenkraft.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A 10 years journey introducing RCM within hydropower: a case study at Vattenfall Vattenkraft2008Inngår i: EuroMaintenance Papers: Conference and Trade Show on Asset Management & Production Reliability ; Brussels Expo, 8 - 10 April 2008, Belgian Maintenance Association , 2008, s. 21:1-21:10Konferansepaper (Fagfellevurdert)
  • 46.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Jonforsen, F.
    Planning for RCM implementation in an outsourcing environment: a case study at a Swedish hydro power plant2002Inngår i: Proceedings of the 16th European Maintenance Congress: Euromaintenance 2002, 2002, s. 19-28Konferansepaper (Fagfellevurdert)
  • 47.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Larsson, Dan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rhen, Mats
    Luleå tekniska universitet.
    Risk analysis and condition monitoring for efficient maintenance planning at Swedish hydro power plants1998Inngår i: Safety and reliability: proceedings of the European Conference on Safety and Reliability, ESREL '98, Trondheim, Norway, 16 - 19 June 1998 / [ed] Stian Lydersen, Amsterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1998, s. 247-253Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Maintenance issues have in recent years grown in importance. Higher demands on availability and quality of products are some of the reasons. These demands have resulted in an increased use of condition monitoring systems, to support an effective maintenance concept. For a complex system, this technique generates an enormous amount of signals which is difficult to diagnose, and a great amount of information which is difficult to handle and interpret for the operator. Therefore, improved diagnosis and decision support tools are necessary, as a complement to the monitoring systems. This paper presents an ongoing project, trying to find a new approach to condition monitor and diagnose Kaplan hydro-power turbines, where the chain from transducer to decision making is under consideration. Risk analysis is adequate for decision making among alternative maintenance tasks and the ambition is a risk model that can be systematically updated with varying economic data and production requirements. Also, the availability is under consideration for the hydro power plant, as a total system, where the owners of the plant should be able to steer the availability according to demand. Another important aspect is the possibility of the condition monitoring system to test itself, which will prevent false alarms.

  • 48.
    Backlund, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Sundqvist, Erik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Continuous improvement: challenges for the project-based organization2018Inngår i: International Journal of Quality & Reliability Management, ISSN 0265-671X, E-ISSN 1758-6682, Vol. 5, nr 7, s. 1306-1320Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose

    There are limited studies of Continuous improvement from the perspective of a project-based organization (PBO). Hence, this article explores challenges that PBOs may encounter when applying Continuous improvement.

    Design/methodology/approach

    An exploratory and qualitative approach has been used, involving six management teams in six different project-based organizations, using focus groups interviews as data collecting method.

    Findings

    A high degree of autonomy among project managers seems to limit a collective approach to project management in PBOs. As a consequence the overall PBO performance becomes subordinate to the individual project performance – an approach opposite to that of Continuous improvement. Further, the management teams themselves seem to uphold a project focus, also complicating improvement initiatives from a PBO perspective.

    Research limitations/implications

    The management teams have been the unit of analysis, where the PBOs mainly conduct projects in an engineering and construction context, and are located in the same country and region. This approach enables the thorough study of a phenomenon, while preconditions for generalization are limited. However, the findings could be used by researchers as a basis for more in-depth studies of specific challenges, and for making surveys to obtain generalization of results.

    Practical implications

    The results can induce awareness and understanding of different challenges if applying Continuous improvement in a PBO, hence a starting point for finding ways to overcome these challenges.

    Originality/value

    The article contributes to an increased understanding of challenges that PBOs may encounter when applying Continuous improvement, confirming and presenting additional findings compared to previous studies.

  • 49.
    Basu, A.P
    et al.
    Department of Statistics, University of Missouri, Columbia, MO, USA.
    Ebrahimi, Nader
    Nothern Illinois University, USA.
    Klefsjö, Bengt
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Multivariate harmonic new better than used in expectation distributions1983Inngår i: Scandinavian Journal of Statistics, ISSN 0303-6898, E-ISSN 1467-9469, Vol. 10, nr 1, s. 19-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Various definitions of multivariate harmonic new better than used in expectation (MHNBUE) life distributions are introduced and their interrelationships are studied. The definitions are multivariate generalizations of the univariate aging property HNBUE which is weaker than the new better than used in expectation (NBUE) property. Various closure properties of the different MHNBUE classes are proved. Some examples are also given to illustrate the relationships between our MHNBUE properties and the MNBUE properties presented by Buchanan and Singpurwalla (1977). We also study the dual multivariate harmonic new worse than used in expectation (MHNWUE) classes

  • 50.
    Bekki, Jennifer M.
    et al.
    Arizona State University, Polytechnic Campus, Mesa, AZ.
    Fowler, John W.
    Arizona State University, Tempe.
    Mackulak, Gerald T.
    Arizona State University, Tempe.
    Kulahci, Murat
    Technical University of Denmark, Lyngby.
    Simulation-based cycle-time quantile estimation in manufacturing settings employing non-FIFO dispatching policies2009Inngår i: Journal of Simulation, ISSN 1747-7778, Vol. 3, nr 2, s. 69-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous work shows that a combination of the Cornish-Fisher Expansion (CFE) with discrete-event simulation produces accurate and precise estimates of cycle-time quantiles with very little data storage, provided all workstations in the model are operating under the first-in-first-out (FIFO) dispatching rule. The accuracy of the approach degrades, however, as non-FIFO dispatching policies are employed in at least one workstation. This paper proposes the use of a power transformation for use in combination with the CFE to combat these accuracy problems. The suggested approach is detailed, and three methods for selecting the λ parameter of the power transformation are given. The results of a thorough empirical evaluation of each of the three approaches are given, and the advantages and drawbacks of each approach are discussed. Results show that the combination of the CFE with a power transformation generates cycle-time quantile estimates with high accuracy even for non-FIFO systems.

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