Ändra sökning
Avgränsa sökresultatet
1234567 51 - 100 av 1463
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 51.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Model-based security system for data acquisition in e-maintenance using artificial immune system and cloud computing2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 4, s. 26-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    eMaintenance solutions are extensively used by the industry today. eMaintenance is an emerging technology aimed to support the industry to achieve effectiveness and efficiency in their maintenance process through enhanced use of Information and Communication Technology (ICT) . One of the essential components is an eMaintenance solution is data acquisition. Supervisory Control and Data Acquisition (SCADA) has been used to manage data acquisition is many industrial systems. Nowadays, modern SCADA systems are available through internet and other networks via IP protocol. An increased use of internet–based solution requires appropriate management approaches to improve the safety and security aspects of a system. Hence, this paper suggests a new security model based security for SCADA systems through Cloud computing and Artificial Immune System (AIS). Furthermore, the paper provides AIS, which is based on Decision Tree (C4.5 algorithm) using clustered feature set. The features set are selected from NSL-KDD cup. It is a new version of KDD dataset. As a result, two Antibodies are generated (that could recognize Normal and Antigen). After applying the resulted antibodies on the testing data set, the outputs are Normal, Antigen, and Unknown. Finally it is treated with Unknown as Antigen. As a result, high accuracy of the suggested model reaches 96.3%.

  • 52.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pangracious, Vinod
    Department of Electrical and Computer Engineering, American University in Dubai,.
    Al-Doori, Mulhim
    Department of Electrical and Computer Engineering, American University in Dubai.
    Artifical Immune System Using Genetic Algorithm And Decision Tree2016Ingår i: International Conference on Bio-engineering for Smart Technologies (BioSMART) 2016, Piscataway, NJ: IEEE, 2016, s. 1-4, artikel-id 7835603Konferensbidrag (Refereegranskat)
    Abstract [en]

    Artificial immune system (AIS) is considered as an adaptive computational intelligence method that could be used for detecting and preventing current computer network threats. AIS generates Antibodies (self) competent in recognizing Antigen (non-self), which is considered as an anomaly technique. This paper aims to develop artificial immune system (AIS) that consists of two levels. Level one is developed using Genetic Algorithm, while level two is developed using C4.5 decision tree algorithm. The proposed system trained with clustered features that are selected from NSL-KDD cup data-set. Each level produces two antibodies (that could recognize Normal and Antigen access-records). The recognition accuracy of the developed system reaches 96%. The behavior of each level is studied. The best feature-set that suits each level is specified.

  • 53.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A critical review of Information Assurance (IA) framework forcondition-based maintenance of railway tracks2017Ingår i: Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016 / [ed] Walls L.,Revie M.,Bedford T, London: CRC Press, 2017, s. 1072-1078Konferensbidrag (Refereegranskat)
    Abstract [en]

    Railway maintenance is faced with increasing demands, including the need to improve service.Data measuring the track state and suitable models or applications are needed to make good maintenancedecisions. This critical review paper investigates many research papers on the use of information assurance (IA)within condition-based maintenance (CBM) on a railway track. An IA framework sheds light on the data andinformation used to make maintenance decisions. The paper considers work on data processing and decisionmakingin CBM. The results show condition monitoring suffers from an inability to determine exact positioningon the track; some data are inaccurate or unavailable. Existing studies have not adequately dealt with data contentor the various technologies used. They focus on integrity, availability, authentication, authorisation and accuracy,but do not consider other IA principles important to understand data.CBMmodels and algorithms have difficultyunderstanding degradation models, and data problems mean it is difficult to make good decisions. There is alack of long term maintenance plans. Models also need to be integrated for more realistic but not necessarilyoptimum solutions and to ensure practical predictions of maintenance. Some models focus on degradation, othersconsider prediction, and still others calculate the maintenance cost; it is difficult to combine these. Overall, dataare inaccurate, there is no testing phase using realistic data, and existing models are insufficient. This has anegative impact on maintenance decisions.

  • 54.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Improvement of Railway Performance: A Study of Swedish Railway Infrastructure2016Ingår i: Journal of Modern Transportation, ISSN 2095-087X, E-ISSN 2196-0577, Vol. 24, nr 1, s. 22-37, artikel-id 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The volume of rail traffic was increased by 5% from 2006 to 2010, in Sweden, due to increased goods and passenger traffic. This increased traffic, in turn, has led to a more rapid degradation of the railway track, which has resulted in higher maintenance costs. In general, degradation affects comfort, safety, and track quality, as well as, reliability, availability, speed, and overall railway performance. This case study investigated the needs of railway stakeholders responsible for analysing the track state and what information is necessary to make good maintenance decisions. The goal is to improve the railway track performance by ensuring increased availability, reliability, and safety, along with a decreased maintenance cost. Interviews of eight experts were undertaken to learn of general areas in need of improvement, and a quantitative analysis of condition monitoring data was conducted to find more specific information. The results show that by implementing a long-term maintenance strategy and by conducting preventive maintenance actions maintenance costs would be reduced. In addition to that, problems with measured data, missing data, and incorrect location data resulted in increased and unnecessary maintenance tasks. The conclusions show that proactive solutions are needed to reach the desired goals of improved safety, improved availability and improved reliability. This also includes the development of a visualisation tool and a life cycle cost model for maintenance strategies.

  • 55.
    Aliyari, Mostafa
    et al.
    Politecnico di Milano.
    Barabadi, Abbas
    UiT The Arctic University of Norway.
    Barababadi, R.
    Amir Kabir College, Jajarm.
    Garmabaki, Amir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Failure and repair data analysis of power distribution systems: a case study2017Ingår i: Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016 / [ed] Walls L.,Revie M.,Bedford T, London: CRC Press, 2017, s. 2046-2053Konferensbidrag (Refereegranskat)
    Abstract [en]

    The basic function of electricity distribution system is to supply electrical energy as economically as possible to customer in different geographic with an accept-able level of reliability and quality [1]. The quality of electricity means the supplied current and voltage waveforms are essentially pure sinusoidal waveforms. By incorporating reliability and maintainability con-siderations in the system design and in the planning of system expansion, operation and maintenance the both quality and safety can be improved [2]. To obtain useful results from system reliability assessments, accurate values of component reliability parameters need to be estimated. If the outage database are collected properly, they can reflecting the conditions in which a component works. Hence, collecting, extraction and exploitation useful information from historical data getting more and more importance. A statistical significance of an outage database depends on the quality and reliability as well as number of records data in the database. Such database would describe the real conditions of network equipment more accurately. This study will exploit unplanned outages in electrical components of low voltage (LV) distribution systems in North Khorasan Electricity Distribution Company (NKEDC). The database containing 64035 outages and 150569 Kwh undistributed energy and total time of 2637430 minutes of outages in LV components from July 2010 to February 2016. Here, the main aim of the analysis is to identify the “Significant Few” failures as well as the current maintainability performance of each identified failure models in the power distribution. Such analysis will give a picture of current situation of the system. To start the analysis two meeting have been conducted with the expertise of company to identified the main failure model in the system. Thereafter, the collect data have been explored. The collected data are very detailed regarding the repair time. However, the recorded failure model and preliminary failure cause are not well collected in database. Moreover, we noticed that cause of the failure are not recorded using appropriate coding system that make extracting the data very difficult. Hence, at the first step appropriate coding system have been developed. In this stage, the required recommendation for improving the data collection have been provide and discussed with the company. Based on failure mechanism, of equipment and expert opinions 23 failure mode have been identified and then maintainability for these identified failure mode have been calculated. The trend test and the serial correlation test should all collected repair data are iid distributed and lognormal distribution is suitable tools to model the most identified failure modes

  • 56.
    Aljumaili, Mustafa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Data Quality Assessment: Applied in Maintenance2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 57.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Data quality assessment using multi-attribute: maintenance perspective2018Ingår i: International Journal of Information and Decision Sciences, ISSN 1756-7017, E-ISSN 1756-7025, Vol. 10, nr 2, s. 147-161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper proposes a model for data quality (DQ) assessment in maintenance. Data has become an increasingly important since most of the maintenance planning and implementations are based on data analysis. Poor DQ reduces customer satisfaction, leading to poor decision making, and has negative impacts on strategy execution. To improve DQ as well as to evaluate the current status, DQ needs to be measured. A measure for DQ could be an important support for decision makers. Multi-criteria decision-making (MCDM) methods can provide a framework for DQ assessment, however, they are not used in literature for DQ assessment. In order to assess DQ, the attributes or KPIs need to be defined, their hierarchy should be designed and the assessment model is proposed to evaluate these attributes. A case study is also presented in this paper. The study shows that MCDM methods could provide qualitative estimation for the quality of DQ attributes.

  • 58.
    Aljumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Metadata-Based Data Quality Assessment2016Ingår i: Vine: The Journal of Information and Knowledge Management Systems, ISSN 0305-5728, E-ISSN 1474-1032, Vol. 46, nr 2, s. 232-250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High quality data and data quality assessment can support the decision-makingprocess. In the literature, discussions of the assessment process are mainly focused on theoretical approaches to content analysis or on user evaluations. Metadata is important source for quality information in any database system, however, it is not considered for data quality assessment. Metadata contains information that describes the data in a database, including the constraints and the database schema. High quality data can be produced by designing a database system with accurate metadata descriptions. Having accurate and detailed metadata will reduce the errors in data values which can lead to data quality issues. In this study, data quality assessment model is proposed based on both content and metadata analysis. The model is validated by developing an application tool to assess the quality of the data in a database based on the proposed model. The results show that metadata can provide important information about the quality of the database and its adoption can help togive faster, more accurate and user independent assessment of data quality.

  • 59.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Multi-Criteria Data Quality Assessment Maintenance perspective2014Ingår i: Proceedings of the 3rd international workshop and congress on eMaintenance: June 17-18 Luleå, Sweden : eMaintenance, Trends in technologies & methodologies, challenges, possibilites and applications / [ed] Uday Kumar; Ramin Karim; Aditya Parida; Philip Tretten, Luleå: Luleå tekniska universitet, 2014, s. 153-158Konferensbidrag (Refereegranskat)
    Abstract [en]

    Data quality (DQ) in maintenance has become an increasinglyimportant aspect to many firms as most of the maintenanceplanning and implementations are based on data analysis. PoorDQ has adverse effects at the operational, tactical, and strategiclevels of any organization. Respectively, poor DQ reducescustomer satisfaction, leading to poor decision making, and hasnegative impacts on strategy execution. To improve DQ as well asto evaluate the current status, DQ need to be measured followingthe fact that only what can be measured can be improved. Ameasure for DQ could be an important support for decisionmakers. In order to assess DQ, related attributes should bedefined. These attributes could be related to the data itself, to themetadata, or to the data representation schemes. After definingthese attributes, an assessment model should be used to evaluatethese attributes. The purpose of this paper is to propose a modelfor DQ assessment. Therefore, a study of DQ attributes and thepossible metrics that could be used to measure these attributes wasundertaken. The proposed model will be applied on datasetprovided by the Swedish Transport Administration (Trafikverket)for validation and to find an estimation measure of the DQ.

  • 60.
    Aljumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Quality of Streaming Data in Condition Monitoring Using ISO 80002016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 703-715Konferensbidrag (Refereegranskat)
    Abstract [en]

    The purpose of this paper is to propose a Data Quality Measurement Model based on ISO 8000 standard. This paper deals about the concepts implied in the measurement process, not about the measures themselves. Poor quality information causes customer dissatisfaction, lost revenue and higher costs associated with additional time to reconcile information. An understanding of the characteristics of the data that determine its quality, and an ability to measure, manage and report on data quality is required. Measurement is a major activity in data quality management. In literature, there are many proposals contributing somehow to the measurement of data quality. However, these measurement methods lack the unification. ISO 8000 provides a framework for improving data quality that can be used independently or in conjunction with quality management systems. ISO 8000 defines characteristics that can be tested by any organization in the data supply chain to objectively determine conformance of the data to ISO 8000.

  • 61.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wandt, Karina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    eMaintenance Ontologies for Data Quality Support2015Ingår i: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 21, nr 3, s. 358-374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose – The purpose of this paper is to explore the main ontologies related to eMaintenance solutions and to study their application area. The advantages of using these ontologies to improve and control data quality will be investigated.Design/methodology/approach – A literature study has been done to explore the eMaintenance ontologies in the different areas. These ontologies are mainly related to content structure and communication interface. Then, ontologies will be linked to each step of the data production process in maintenance.Findings – The findings suggest that eMaintenance ontologies can help to produce a high quality data in maintenance. The suggested maintenance data production process may help to control data quality. Using these ontologies in every step of the process may help to provide management tools to provide high quality data.Research limitations/implications – Based on this study, it can be concluded that further research could broaden the investigation to identify more eMaintenance ontologies. Moreover, studying these ontologies in more technical details may help to increase the understandability and the use of these standards. Practical implications – It has been concluded in this study that applying eMaintenance ontologies by companies needs additional cost and time. Also the lack or the ineffective use of eMaintenance tools in many enterprises is one of the limitations for using these ontologies.Originality/value – Investigating eMaintenance ontologies and connecting them to maintenance data production is important to control and manage the data quality in maintenance.Paper type Research Paper

  • 62.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Mahmood, Yasser Ahmed
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Assessment of railway frequency converter performance and data quality using the IEEE 762 Standard2014Ingår i: International Journal of Systems Assurance Engineering and Management, ISSN 0975-6809, E-ISSN 0976-4348, Vol. 5, nr 1, s. 42694-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reliability, availability and maintainability analysis is one of the most important tools for measuring system performance. The performance of a traction power supply system (TPSS) can be measured using the data collected from frequency converters, as these converters constitute the main part of the TPSS. The quality of the collected data should be good enough to provide the correct and complete information necessary for assessment of frequency converter performance. Many methods can be used to assess the performance of converters such as neural networks, fuzzy logic and standards. The IEEE 762 Standard offers a methodology that can provide key performance indicators for power generation units. This standard has been chosen for its widespread acceptance and applicability. To be able to evaluate a converter’s performance, IEEE 762 indexes should be calculated using data such as the downtime, reserve shutdown hours and service hours. Therefore, the purpose of this study is to assess the performance of the Swedish TPSS frequency converters using IEEE 762, and to assess the quality of data by inspecting their compatibility with this standard. In this study, an application has been developed to generate the missing information and to calculate the indexes provided by the standard, in order to evaluate the power converters’ performance. A case with sample data is also discussed in this paper.

  • 63.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rauhala, Ville
    Kemi-Tornio University of Applied Science.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Jonsson, Katrin
    Department of Informatics, Umeå University.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Aspects of data quality in eMaintenance: a case study of process industry in northern Europe2014Ingår i: Engineering Asset Management 2011: Proceedings of the Sixth World Congress on Engineering Asset Management / [ed] Jay Lee; Jun Ni; Jagnathan Sarangapani; Joseph Mathew, London: Encyclopedia of Global Archaeology/Springer Verlag, 2014, s. 41-51Konferensbidrag (Refereegranskat)
    Abstract [en]

    Increased environmental awareness in the industry combined with the globalized market economy makes increasing demands for sustainable and efficient resource utilization. In this context, maintenance plays a critical role by linking business objectives to the strategic and operational activities aimed at retaining the system’s availability performance, cost-efficiency and sustainability. Performing maintenance effectively and efficiently requires corresponding infrastructure for decision-support provided through eMaintenance solutions. A proper eMaintenance solution needs to provide services for data acquisition, data processing, data aggregation, data analysis, data visualization, context-sensing etc. To en Quality of Service (QoS) in eMaintenance solutions, the performance of both system-of-interest, enabling systems and related processes have to be measured and managed. However, the QoS has to be considered on all aggregation levels and encompass the aspects of Content Quality (CQ), Data Quality (DQ) and Information Quality (IQ). Hence, the purpose of this paper is to study and describe some aspects of DQ in eMaintenance related to process industry in northern Europe

  • 64.
    Aljumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rauhala, Ville
    Kemi-Tornio University of Applied Science Technology.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Data quality in eMaintenance: a call for research2011Ingår i: MPMM 2011: Maintenance Performance Measurement & Management: Conference Proceedings / [ed] Diego Galar; Aditya Parida; Håkan Schunnesson; Uday Kumar, Luleå: Luleå tekniska universitet, 2011, s. 69-73Konferensbidrag (Refereegranskat)
    Abstract [en]

    Effective and efficient maintenance requires a proper information logistics, which can be delivered through eMaintenance solutions. Development of eMaintenance solutions faces extensive challenges. One of these challenges is how to ensure the quality of data used in different eMaintenance solutions. Data Quality (DQ) concerns all phases of the maintenance process. The purpose of this paper is to answer the research question: how should DQ be considered and managed when developing eMaintenance solutions. To deal with such challenges a case study was conducted at a mining company. Empirical data has been collected through interviews, observations, archival records and workshops. The data analysis has been based on an empirical framework that supports the identification of required information services. Conditions that support the DQ and the information logistics, along with that, support the maintenance process have been presented. These aspects have also been related to the phases of a generic maintenance process.

  • 65.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Study of aspects of data quality in e-maintenance2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 4, s. 3-14Artikel i tidskrift (Refereegranskat)
  • 66.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wandt, Karina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    eMaintenance ontologies and data production2012Ingår i: Proceedings of the 2nd International Workshop & Congress on eMaintenance: Dec 12-14 Luleå, Sweden : eMaintenace: trends in technologies and methodologies, challenges, possibilities and applications / [ed] Ramin Karim; Aditya Parida; Uday Kumar, Luleå: Luleå tekniska universitet, 2012, s. 191-196Konferensbidrag (Refereegranskat)
  • 67.
    Al-Jumaili, Mustafa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wandt, Karina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    eMaintenance Related Ontologies2012Rapport (Övrigt vetenskapligt)
  • 68.
    Allahkarami, Zeynab
    et al.
    Faculty of Engineering, Department of Mining Engineering, University of Tarbiat.
    Sayadi, Ahmad Reza
    Tarbiat Modares University, Faculty of Engineering, Department of Mining Engineering, University of Tarbiat.
    Lanke, Amol
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability Analysis of Motor System of Dump Truck for Maintenance Management2016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 681-688Konferensbidrag (Refereegranskat)
    Abstract [en]

    Dump truck is one of the main machinery in open pit mines. From an economic point of view, more than 50–60 % of production costs in open pit mines are allocated to hauling and loading costs, so it is important to keep equipment in good condition. Reliability is a useful tool for evaluating the performance of this machine. In this research, the reliability of motor subsystem of a dump truck in Miduk Copper Mine in Iran has been analyzed. The failure data were collected during 20 months of dump truck operation. Trend and serial correlation tests were used to validate the assumption of independent and identically distribution (IID). According to tests, the data are independent and identically distributed therefore the renewal process technique is used for modelling. For finding the best-fit distribution, different types of statistical distributions were tested using the Easyfit software. The analysis results indicated the time between failures (TBF) data obey the Weibull (3p) distribution. The developed model based on these data showed that the reliability of the motor subsystem decreases to a zero value after approximately 430 h of operation. Regarding to the obtained reliability plot, preventive reliability-based maintenance time interval for 90 % reliability levels for machine in the motor subsystem is 21 h.

  • 69.
    Almgren, Gunnar
    et al.
    Luleå tekniska universitet.
    Almgren, T.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Just-in-time and right-in-space1996Ingår i: Minerals Industry International, ISSN 0955-2847, Vol. 1032, s. 26-29Artikel i tidskrift (Refereegranskat)
  • 70.
    Almgren, Gunnar
    et al.
    Luleå tekniska universitet.
    Kumar, UdayLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.Vagenas, NickLuleå tekniska universitet.
    Mine mechanization and automation: proceedings of the second International Symposium on Mine Mechanization and Automation, Luleå, Sweden, 7-10 June 19931993Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 71.
    Alsyouf, Imad
    et al.
    Industrial Engineering and Engineering Management, University of Sharjah, Sharjah, United Arab Emirates.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Al-Ash, Lubna
    Industrial Engineering and Engineering Management, University of Sharjah, Sharjah, United Arab Emirates.
    Al-Hammadi, Muna
    Industrial Engineering and Engineering Management, University of Sharjah, Sharjah, United Arab Emirates.
    Improving baggage flow in the baggage handling system at a UAE-based airline using lean Six Sigma tools2019Ingår i: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 30, nr 3, s. 432-452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a real successful implementation of lean six sigma methodology to continuously improve the baggage flow in a baggage handling system (BHS), by identifying the causes of mishandled baggage, and deriving solutions to enhance BHS performance. The results show that the main critical problems were low system reliability and the high number of bags passing through manual-encoding-stations. This research illustrates how to avoid baggage congestion and provides applicable and cost-effective solutions. The success of this project made the organisation aware of the opportunities that the application of lean Six Sigma methodology created in the aviation and airport sector.

  • 72.
    An, Bolun
    et al.
    School of Civil Engineering, Beijing Jiaotong University, Beijing, China. Beijing Key Laboratory of Track Engineering, Beijing, China. Beijing Engineering Research Centre of Rail Traffic Line Safety and Disaster, Beijing, China.
    Gao, Liang
    School of Civil Engineering, Beijing Jiaotong University, Beijing, China. Beijing Key Laboratory of Track Engineering, Beijing , China. Beijing Engineering Research Centre of Rail Traffic Line Safety and Disaster, Beijing, China.
    Xin, Tao
    School of Civil Engineering, Beijing Jiaotong University, Beijing, China. Beijing Key Laboratory of Track Engineering, Beijing, China. Beijing Engineering Research Centre of Rail Traffic Line Safety and Disaster, Beijing, China.
    Lin, Jing
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    An approach to evaluate wheel-rail match properties considering the flexibility of ballastless track: Comparison of rigid and flexible track models in wheel-rail profile matching2019Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 22, nr 3, s. 5-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many different wheel/rail profiles are used in the China high-speed railway, and vehicle operation safety and comfort will decrease if the inappropriate wheel-rail profile pair is used. To solve the problem of estimating the wheel-rail match, many numerical models, including vehicle system dynamic models and wheel-rail rolling contact models, have been established to analyse the wheel-rail dynamic responses. Both methods have less consideration of the flexibility and vibration characteristics of ballastless track, leading to deviations in the calculation of middle and high frequency vibration. This paper proposes a vehicle-flexible track coupling model and compares it with the vehicle dynamic model (vehicle-rigid track model). In the rigid track model, only the track irregularities are considered in the track module; the vibrations and deformations of rails, track slab and the foundation are considered in the flexible track model. Taking Chinese CRH3 series wheel profile S1002CN and rail profile CHN60 as examples and considering different track excitations, the two models are compared. The wheel-rail interaction forces, wheel-rail wear depths, wear volumes and vehicle accelerations are chosen as analysis indices for the comparative study.

    The results show that the wheel-rail forces of the flexible track model are larger than the rigid track model in the frequency range from 70 to 120Hz, while they decrease obviously in the frequency range above 150Hz. The differences in wear depths and volumes between the two models exceed 10%. Therefore, the flexible track model should be considered when studying the match properties of different wheel-rail pairs.

  • 73.
    Anand, Adarsh
    et al.
    Department of Operational Research, University of Delhi.
    Agarwal, Mohini
    University of Delhi.
    Bansal, Gunjan
    Department of Operational Research, University of Delhi.
    Garmabaki, Amir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Studying product diffusion based on market coverage2016Ingår i: Journal of Marketing Analytics, ISSN 2050-3326, Vol. 4, nr 4, s. 135-146, artikel-id 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Market coverage is an important attribute for determining the success of a product. The larger the market covered by a product is, the higher the amount of sales for that product will be. Market coverage strategies thus contribute to the success of a product in tapping the market. In this study, we emphasize the impact of market coverage on the rate of adoption in determining product sales. New product diffusion models based on the market covered are proposed. A methodological approach of weighted criteria is implemented to evaluate and rank the proposed models. The analysis is conducted on real-life sales datasets

  • 74.
    Anandika, Rayendra
    et al.
    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.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Non-destructive measurement of artificial near-surface cracks for railhead inspection2019Ingår i: Insight (Northampton), ISSN 1354-2575, E-ISSN 1754-4904, Vol. 61, nr 7, s. 373-379Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper delivers a study involving the inspection of artificial surface cracks with depths ranging from 0.25-2.5 mm from the surface and with a crack angle of 30°, which is a typical angle for surface cracks in railheads. The inspections were conducted using three different techniques: phased array ultrasonics, single-element ultrasonics and alternating current potential drop (ACPD). For the ultrasonic techniques, the study focused on employing either longitudinal or shear wave signals. In the railway industry, shallow surface cracks in railheads are caused by rolling contact fatigue (RCF). In this study, artificial defects were made, allowing the authors to explore the extent to which the ultrasonic measurement techniques can detect such defects. The negative effect of a dead zone near to the surface in the ultrasonic tests was reduced by using a wedge attachment. A discussion on the extent to which the techniques can be used in field tests was also provided. The most important result is that shallow cracks ranging from 0.25-2.5 mm were successfully characterised with acceptable accuracy. The 2.5 mm-deep crack can be measured with an accuracy of 0.8% using a 20 MHz single-element probe and with an accuracy of 3.5% using a 5 MHz phased array (64 elements, 0.6 mm pitch). The characterisations were performed using a filtering method that was developed in this study.

    1675605

  • 75.
    Andersson, Andreas
    et al.
    Electric Propulsion Systems Department, Volvo Car Group, Gothenburg, Sweden.
    Lennström, David
    oise, Vibrations, and Harshness Department, Volvo Car Group, SE-405 31 Gothenburg.
    Nykänen, Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Influence of Inverter Modulation Strategy on Electric Drive Efficiency and Perceived Sound Quality2016Ingår i: IEEE Transactions on Transportation Electrification, ISSN 2332-7782, Vol. 2, nr 1, s. 24-35, artikel-id 7370814Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an evaluation of differentmodulation techniques and different levels of switching frequencyrandomization for a rear axle electrical drive unit used in auto-motive applications. Inverter and machine losses, and perceivedsound quality of high-frequency acoustic noise are investigated byfinite element calculations, experimental testing, and subjectivenoise assessment. Additionally, stator current harmonics, airgapflux density harmonics, and force density harmonics are comparedfor space vector modulation (SVM) and discontinuous pulsewidthmodulation through finite element modeling. The main conclusionis that, primarily in the field weakening region, significant energysavings can be achieved (up to 17% decrease in total inverter losseswith a switching frequency of 10 kHz). This is obtained withoutdeterioration of perceived sound quality by the use of discontinu-ous pulsewidth modulation with switching frequency randomiza-tion. Furthermore, randomization of the switching frequency doesnot improve the perceived sound quality of the acoustic noise whenusing SVM. However, for discontinuous pulsewidth modulation,improvements in perceived sound quality when randomizing theswitching frequency are observed, primarily below base speed.

  • 76. Appelgren, J
    et al.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nord, G
    Automation and smart drill rigs2006Ingår i: Mine planning and equipment selection 2006: Fifteenth International Symposium on Mine Planning & Equipment Selection / [ed] Marilena Cardu ; Enrica Michelotti, Fiordo , 2006Konferensbidrag (Refereegranskat)
  • 77.
    Arasteh Khouy, Iman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cost-effective maintenance of railway track geometry: a shift from safety limits to maintenance limits2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Railway infrastructure is a complex system which comprises different subsystems. Long life span is one of the important aspects of this prime mode of transport. However, the useful life of its assets is highly dependent on the maintenance and renewal strategy used during the assets’ life cycle. Today’s demands on the railway industry call for increased capacity, including more trains, travelling at higher speeds with higher axle loads. This increased usage results in higher degradation of railway assets and higher maintenance costs. Formerly, railway maintenance procedures were usually planned based on the knowledge and experience of the infrastructure owner. The main goal was to provide a high level of safety, and there was little concern for economic issues. Today, however, the deregulated competitive environment and budget limitations are forcing railway infrastructures to move from safety limits to cost-effective maintenance limits to optimise operation and maintenance procedures. The goal is to make operation and maintenance cost-effective while still meeting high safety standards.One of the main parameters to assure railway safety and comfortable railway service is to maintain high quality of track geometry. Poor quality of track geometry, directly or indirectly, 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 etc.). The aim of this study is to develop a methodology to optimise track geometry maintenance by specifying cost-effective maintenance limits. The methodology is based on reliability and cost analysis and supports the maintenance decision-making process. The thesis presents a state-of-the-art review of track geometry degradation and maintenance optimisation models. It also includes a case study carried out on the iron ore line in the north of Sweden to analyse the track geometry degradation and discuss possible reasons for the distribution of failures along the track over a year. It describes Trafikverket’s (Swedish Transport Administration) maintenance strategy regarding measuring, reporting on and improving track quality, and it evaluates the efficiency of this strategy. It introduces two new approaches to analyse the geometrical degradation of turnouts due to dynamic forces generated from train traffic. In the first approach, the recorded measurements are adjusted at crossing point and then the relative geometrical degradation of turnouts is evaluated by using two defined parameters, the absolute residual area (ARa) and the maximum settlement (Smax). In the second approach, various geometry parameters are defined to estimate the degradation in each measurement separately. It also discusses optimisation of the track geometry inspection interval with a view to minimising the total ballast maintenance costs per unit traffic load. The proposed model considers inspection time and the maintenance-planning horizon time after inspection and takes into account the costs associated with inspection, tamping and risk of accidents due to poor track quality. Finally, it proposes a cost model to identify the cost-effective maintenance limit for track geometry maintenance. The model considers the actual longitudinal level degradation rates of different track sections as a function of million gross tonnes (MGT) / time and the observed maintenance efficiency.

  • 78.
    Arasteh khouy, Iman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Optimization of track geometry maintenance: a study of track geometry degradation to specify optimal inspection intervals2011Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Railway infrastructure is a complex system which comprises different subsystems. Long useful life span is one of the important aspects of this prime mode of transport. The useful life length of its assets is highly dependent on the maintenance and renewal strategy used during its life cycle. Today’s demands on the railway industry call for increased capacity, including more trains, travelling at higher speeds with higher axle loads. This increased usage will result in higher degradation of railway asset and higher maintenance costs. However, due to the competitive environment and limited budgets, railway infrastructure managers are compelled to optimize operation and maintenance procedures to decrease operation and maintenance costs while meeting high safety standards. To assure track safety and maintain high quality, a cost effective track maintenance strategy is required, one based not only on technical and/or safety limits but also on cost-effective maintenance thresholds. RAMS (Reliability, Availability, Maintainability and Safety) and LCC (Life Cycle Cost) analyses, which are derived from reliable track condition data, provide an approach to specify cost effective maintenance strategy to lessen corrective maintenance actions and downtimes.One of the main parameters to assure railway safety and comfortable railway service is to maintain high quality of track geometry. Poor track geometry quality, directly or indirectly, 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, switch, crossings etc.). The aim of this study is to develop a methodology to optimize track geometry maintenance by using historical geometry data. The methodology is based on reliability and cost analysis and supports the maintenance decision-making process to identify cost-effective inspection interval. An important phase of track geometry maintenance optimization is to estimate the track degradation rate. Obtaining knowledge about degradation helps to properly schedule maintenance activities such as inspection and tamping.The thesis provides a methodology to identify a cost-effective inspection interval based on track degradation rate and cost drivers. It contains state-of-the-art track geometry maintenance optimization. It describes Trafikverket’s (Swedish Transport Administration) maintenance strategy regarding measurements, reporting on and improving track quality, and it evaluates the efficiency of this strategy. Finally, it includes a case study carried out on the iron ore line in north of Sweden that runs from Boden to Gällivare to evaluate track geometry degradation and analyze the probability distributions of failures. A cost model is developed in order to find optimal inspection interval.Keywords: Track geometry degradation, Track maintenance optimization, Maintenance planning, Tamping

  • 79.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Optimisation of track geometry inspection interval2014Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 5, s. 546-556Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The measurement and improvement of track quality are key issues in determining the time at which railway maintenance must be performed and its cost. Efficient track maintenance ensures optimum allocation of limited maintenance resources which has an enormous effect on maintenance efficiency. Applying an appropriate tamping strategy helps reduce maintenance costs, making operations more cost-effective and leading to increased safety and passenger comfort levels. This paper discusses optimisation of the track geometry inspection interval with a view to minimising the total ballast maintenance costs per unit traffic load. The proposed model considers inspection time, the maintenance-planning horizon time after inspection and takes into account the costs associated with inspection, tamping and risk of accidents due to poor track quality. It draws on track geometry data from the iron ore line (Malmbanan) in northern Sweden, used by both passenger and freight trains, to find the probability distribution of geometry faults.

  • 80.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cost-effective track geometry maintenance limits2016Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 230, nr 2, s. 611-622Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the past, railway maintenance actions were usually planned based on the knowledge and experience of the infrastructure owner. The main goal was to provide a high level of safety, and there was little concern about economic and operational optimisation issues. Today, however, a deregulated competitive environment and budget limitations are forcing railway infrastructures to move from safety limits to cost-effective maintenance limits to optimise operation and maintenance procedures. By so doing, one widens the discussion to include both operational safety and cost-effectiveness for the whole railway transport system. In this study, a cost model is proposed to specify the cost-effective maintenance limits for track geometry maintenance. The proposed model considers the degradation rates of different track sections and takes into account the costs associated with inspection, tamping, delay time penalties, and risk of accidents due to poor track quality. It draws on track geometry data from the Iron Ore Line (Malmbanan) in northern Sweden, used by both passenger and freight trains, to estimate the geometrical degradation rate of each section. The methodology is based on reliability and cost analysis and facilitates the maintenance decision-making process to identify cost-effective maintenance thresholds.

  • 81.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Geometrical degradation of switches and crossings on a Swedish heavy haul railroad: a case study2013Ingår i: Proceedings of 10th International Heavy Haul Association Conference, New Delhi, India, 2013, Vol. 1, s. 26-32Konferensbidrag (Refereegranskat)
    Abstract [en]

    Switches and crossings (S&Cs) are one of the most critical components of railway track systems in terms of safety, operation and maintenance. Each year, a considerable part of the maintenance budget is spent on inspection, maintenance and renewal of S&Cs. However, applying a cost-effective maintenance strategy helps to achieve the best performance at the lowest possible cost. In Sweden, the geometry of S&Cs is inspected at pre-defined time intervals by the STRIX track measurement car. In this paper, time series for the measured longitudinal level of S&Cs on the Iron Ore Line (Malmbanan) in northern Sweden have been used. Two parameters have been defined in this study, namely the absolute residual area (ARa) and the maximum settlement (Smax), to analyse the geometrical degradation of switches and crossings due to dynamic forces generated from train traffic. The paper also evaluates the growth rate of the longitudinal level degradation as a function of million gross tonnes (MGT). The results facilitate correct decision making in the maintenance process through understanding the degradation rate and defining the optimal maintenance thresholds for the planning process. In the long run this will lead to a cost-effective maintenance strategy with optimized inspection and maintenance intervals.

  • 82.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Geometrical degradation of railway turnouts: a case study from a Swedish heavy haul railroad2014Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 6, s. 611-619Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Turnouts are critical components of track systems in terms of safety, operation and maintenance. Each year, a considerable part of the maintenance budget is spent on their inspection, maintenance and renewal. Applying a cost-effective maintenance strategy helps to achieve the best performance at the lowest possible cost. In Sweden, the geometry of turnouts is inspected at predefined time intervals using the STRIX / IMV 100 track measurement car. This study uses time series for the measured longitudinal level of turnouts on the Iron Ore Line (Malmbanan) in northern Sweden. Two different approaches are applied to analyse the geometrical degradation of turnouts due to dynamic forces generated by train traffic. In the first approach, the recorded measurements are adjusted at the crossing point and then the relative geometrical degradation of turnouts is evaluated by using two defined parameters, the absolute residual area and the maximum settlement, In the second approach, various geometry parameters are defined to estimate the degradation in each measurement separately. The growth rate of the longitudinal level degradation as a function of million gross tonnes / time is evaluated. The proposed methods are based on characterisation of the individual track measurements. The results facilitate correct decision-making in the maintenance process through understanding the degradation rate and defining the optimal maintenance thresholds for the planning process. In the long run, this can lead to a cost-effective maintenance strategy with optimised inspection and maintenance intervals.

  • 83.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Evaluation of track geometry maintenance for heavy haul railroad in Sweden: a case study2014Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 5, s. 496-503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The measurement and improvement of track quality are key issues in determining both the restoration time and cost of railway maintenance. Applying the optimal tamping strategy helps reduce maintenance costs, making operations more cost effective and leading to increased safety and passenger comfort. In this paper, track geometry data from the iron ore line (Malmbanan) in northern Sweden, which handles both passenger and freight trains, are used to evaluate track geometry maintenance in cold climate. The paper describes Trafikverket’s (Swedish Transport Administration) tamping strategy and evaluates its effectiveness in measuring, reporting, and improving track quality. Finally, it evaluates the performance of the maintenance contractor and discusses the importance of the functional requirements stated in the outsourcing contracts.

  • 84.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Nissen, Arne
    Trafikverket.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Evaluation of track geometry degradation in Swedish heavy haul railroad: a case study2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 2, s. 11-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The measurement and improvement of track quality are key issues in determining both the time and cost of railway maintenance. Efficient track geometry maintenance ensures optimum allocation of limited maintenance resources and has an enormous effect on maintenance efficiency. Applying the appropriate tamping strategy also helps reduce maintenance costs, making operations more cost effective and leading to increased safety and passenger comfort. In this paper, track geometry data from the iron ore line in northern Sweden, which handles both passenger and freight trains, are used to calculate track quality degradation trend in a cold climate. The paper describes Trafikverket’s (Swedish Transport Administration) tamping strategy and illustrates the distribution of safety failures in different seasons. It also analyses the track geometry degradation and discuss about the possible reasons for distribution of failures over a year and along the track.

  • 85.
    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 applications2019Proceedings (redaktörskap) (Refereegranskat)
  • 86. Asl, Aliakbar Golshani
    et al.
    Ahmadzadeh, Farzaneh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Risk prioritization based on health, safety and environmental factors by using fuzzy FMEA2013Ingår i: Vol. 1, nr 4, s. 233-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Failure Mode and Effects Analysis is assessing technique which relies to the rule of preventing failure, which is used to identify potential hazards. This method is used with minimum risks to predict the problems and deficits in design stage or development of the processes and services in organizations. The methods main principal is based on multiplying three main parameters: severity, occurrence, detection. This method with all the advantages still has minor disadvantages that in this paper attempts has been made to eliminate these deficiencies by fuzzification. Results show that fuzzy FMEA will enables us to evaluate situations correctly and precisely.

  • 87.
    Asplund, Matthias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wayside Condition Monitoring System for Railway Wheel Profiles: Applications and Performance Assessment2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The railway is an important mode of transport, due to its environmental friendliness, high safety level, and low energy consumption combined with a high transport capacity, among other factors. The Swedish railway network is old, there has been almost no expansion of the network during the past few decades, and more traffic is expected. Therefore, there is currently a demand for more track capacity and, in the short term, the existing network is expected to deliver the increased capacity. The railway operators in the network have a large impact on train delays, and wheel failures are one large contributor of delays. Delays destroy capacity and, therefore, capacityconsuming failures, such as abnormal wheels, need to be minimised. This can be achieved by using appropriate condition monitoring for the wheels on the track to find potential capacity consumers before failures happen. Therefore, the condition of the wheel-rail interface is important, since the state of the wheel influences that of the rail and vice versa. The monitoring of rail profiles is already being performed, but the monitoring of wheel profiles is still in the development phase. This thesis treats the applications and performance assessment of a wheel profile measurement system (WPMS), and presents case studies focusing on its system and measurement performance. The proposed applications concern how the information from the WPMS can be integrated with information from other data sources and with physical models to obtain a true current picture of the wheel behaviour. The thesis investigates the measurement performance of the WPMS by using a paired T-test and a number of quality measures, e.g. the reproducibility and repeatability, the precision-to-tolerance ratio and the signal-to-noise ratio. In conclusion, this thesis shows that the WPMS works well with an expected level of reliability in a harsh climate with respect to its measurement and system performance. By combining other data with the data from the WPMS, potentially abnormal wheels can be found in an early stage if the proposed new maintenance limit for the wheel parameter of the flange height is implemented. Furthermore, through adding a physical model to the process, the real contact condition of the actual wheel-rail interface can be evaluated and measurement deviations can be found. However, the wheel parameters, as well as the entire profile, need a high measurement quality with little variation, which seems to be an issue with respect to the measurement performance when advanced calculations are to be done. Therefore, a new approach for evaluating measurement performance has been developed using established statistical tools and quality measures with predefined acceptance limits; with the help of this approach, one can differentiate between the variation in the measurements originating in the different measurement units and the variation originating in the wheels. This new approach can be applied to judge the measurement performance of wheel profile condition-monitoring systems, and can also be implemented for other condition-monitoring systems to evaluate their measurement performance. Finally, this approach promotes the development of a condition-based maintenance policy by providing more reliable information for maintenance decision makers.

  • 88.
    Asplund, Matthias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wayside Condition Monitoring Technologies for Railway Systems2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The railway is an important mode of transport, due to its environmental friendliness, high safety level, and low energy consumption, among other reasons. Railways provide a sustainable means of transporting a large amount of freight and passengers, in a cost-effective and comfortable way. The railway system has a large number of stakeholders and a small improvement in the system will give many advantages, including financial savings and an increase in the quality of service. The Swedish railway network is old and there has been almost no expansion of the network during the past few decades. There is currently a demand for more track capacity and there are no more tracks availably at the network; therefore, the existing network is expected to deliver more capacity.The railway operators are the largest cause of train delays and wheel failures are one major contributor of the delays caused by operators. The infrastructure manager is the second largest owner of train delays, and a large contributor of their train delays is switches and crossings (S&Cs). This thesis shows proposals for how condition monitoring technology can be used more efficiently for both the infrastructure and the rolling stock to increase the reliability of their critical items by decreasing train delay. Firstly, the condition of the wheel-rail interface is important, in that a bad wheel influences the rail and vice versa. The monitoring of rail profiles is already in use, but the monitoring of wheel profiles is still in the development phase. This thesis shows the performance of a wheel profile measurement system (WPMS) for an extreme climate, and a case study of performance measures such as the accuracy and reliability of the system is presented. An additional topic dealt with is how the information from the WPMS can be combined with that from the wheel defect detectors to find early indications of wheels with bad behaviour. Secondly, the S&C is an essential component of a railway system in that it increases the flexibility by diverting traffic, but S&Cs need adequate support to work properly. A camera-monitoring method for S&Cs is presented which increases the inspection frequency and decreases the human activities on the track and the train delay. In conclusion, this thesis shows that the WPMS investigated works well with a high level of performance concerning measurement accuracy and reliability in an extreme climate, and that there is still some potential for improving the system. The combination of the WPMS and wheel defect detectors shows that wheels with a high flange height have a higher probability of ending up as wheels suffering from failures. A new maintenance limit for the flange height can reduce the number of wheel defects on the track. Camera-monitoring of the S&C will increase the availability and reliability of this item and even reduce the time on the track required for the maintenance action “check” through fewer inspections and maintenance actions. These proposed monitoring techniques can improve the railway system reliability by reducing the consequential train delay times, by decreasing the number of failures of wheels and S&Cs.

  • 89.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring and e-maintenance solution of railway wheels2014Ingår i: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 20, nr 3, s. 216-232Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose – The purpose of this paper is to investigate the failure-driven capacity consumption of wheels on the track, to determine whether there are some relations to vehicle wheel configurations that show a larger amount of failures, and to ascertain the influence of the temperature and the travelling direction of the train on the number of events. This information can be used to develop prognostic health management (PHM) so that more track capacity can be gained without modifications, re-building or re-investments. Design/methodology/approach – This paper presents a study of 1,509 warning and alarm events concerning train wheels. The data come from the infrastructure manager’s wheel defect detectors and wheel profile measurement system. These data have been analysed and processed to find patterns and connections to different vehicles, travelling directions and temperatures. Findings – Lower temperatures increase the probability of wheels having high vertical forces. Trains with different wheel configurations show different results. With high vertical forces, the probability of wheel failures at axle 6 and 7 is high for locomotives with two bogies and three axles in each bogie (2x3). All these findings can be used to develop the maintenance, monitoring and inspection principles for wheels. Practical implications – The inspection of wheels to detect failures needs to be more frequent on days and in seasons with lower temperatures. The wheel inspection should be performed more frequently at axle 6 and 7 for locomotives with a 2x3 wheel configuration. The inspection and monitoring of wheels need to be carried out more carefully for trains travelling south, to avoid a large amount of wheels with high force levels rolling in the southern direction. Originality/value – The analysis carried out in this paper identifies important factors that correlate with the high occurrence of wheel defects. It also proposes a conceptual e-maintenance model for the combination of wheel condition monitoring data from different system. The value of this study is the provision of information to support prognostic and health management system to support proactive maintenance.

  • 90.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Data quality assessment of automatic wheel profile measurement systems2016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 717-738Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of this paper is to present a method for the quality assessment of data from a condition monitoring system for rolling stock wheels to ascertain if the data have the right quality to be used for further analyses. This quality assessment will also show if there are variations between different measurement units for the same system, and if there are relations between different wheel parameter measurements, speed and time. The assessment of data is accomplished using the quality dimension freedom of error. There are two different data sources, namely an automatic wheel profile measurement system and a manual wheel profile measurement device. The manual measurements of wheel profiles are used for verifying the accuracy of the automatic wheel profile measurements, which constitute the larger data set. The proposed method for evaluating the data quality is demonstrated using the data from a specific condition monitoring system. The results show some inconsistencies indicating that this system lacks quality in the dimension of freedom of error and that there is need for internal calibration or self-adjustment of the studied system for quality reasons.

  • 91.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Prognostic and health management of wheel condition: integration of wheel defect detection and wheel profile monitoring data2012Ingår i: Proceedings of the 2nd International Workshop & Congress on eMaintenance: Dec 12-14 Luleå, Sweden : eMaintenace: trends in technologies and methodologies, challenges, possibilities and application / [ed] Ramin Karim; Adyita Parida; Uday Kumar, Luleå: Luleå tekniska universitet, 2012, s. 15-22Konferensbidrag (Refereegranskat)
  • 92.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik. The Swedish Transport Administration, Trafikverket.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schoech, Wolfgang
    3Speno International, Meyrin, Switzerland.
    A Nordic heavy haul experience and best practices2017Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 231, nr 7, s. 794-804Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article summarizes the experiences gained at the Nordic heavy haul line “Malmbanan” located in Northern Sweden and Norway during the years 2007 to 2015 and the resulting best practice. Unique long-term information of field trials and monitoring from the on-going development for maintenance of rail and wheel has been described. The reported results come from the rail profile measurements using MiniProf and HC-recordings with Eddy-current devices and visual inspection on 43 test sections. The monitoring has been continuous since the project started, to reveal a deep insight into the complex wheel–rail interaction and provide understanding of the effect of applying optimized specifications. This was particularly important in view of the increasing traffic load that contributed to doubling of the yearly grinding campaigns. This article presents in particular the new MB5 profile, the wear rate behaviour between two different curves, impacts of gauge widening on rail rolling contact fatigue and the speed of gauge widening as well as the seasonal impact on the crack propagation. The presently applied maintenance strategy is discussed together with other experiences. The article finishes with some conclusions and an outlook into further work.

  • 93.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Gustafsson, Per
    SWECO Energuide AB.
    Nordmark, Thomas
    LKAB.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Palo, Mikael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wandt, Karina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability and measurement accuracy of a condition monitoring system in an extreme climate: a case study of automatic laser scanning of wheel profiles2014Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 6, s. 695-704Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Iron Ore Line (Malmbanan) is a 473 km long track section located in northern Sweden and has been in operation since 1903. This track section stretches through two countries, namely Sweden and Norway, and the main part of the track runs on the Swedish side, where the owner is the Swedish Government and the infrastructure manager is Trafikverket (the Swedish Transport Administration). The ore trains are owned and managed by the freight operator and mining company LKAB. Due to the high axle load exerted by transportation of the iron ore, 30 tonnes, and the high demand for a constant flow of ore and pellets, the track and wagons must be monitored and maintained on a regular basis. The condition of the wagon wheel is one of the most important aspects in this connection, and here the wheel profile plays an important role. For this reason an automatic laser-based wheel profile monitoring system (WPMS) has been installed on this line using a system lifecycle approach that is based on the reliability, availability, maintainability and safety (RAMS) approach for railways. The system was prepared and installed and is being operated in a collaborative project between the freight operator and infrastructure manager. The measurements are used to diagnose the condition of the wheels, and to further optimize their maintenance. This paper presents a study of the concepts and ideas of the WPMS, and the selection, installation and validation of the equipment using a system lifecycle approach that is based on RAMS for railways. Results from the profile measurements and validation are shown. The system’s reliability during performance in extreme climate conditions, with severe cold and large quantities of snow, is presented. Then the benefits, perceived challenges and acquired knowledge of the system are discussed, and an improved V-model for the lifecycle approach is presented.

  • 94.
    Asplund, Matthias
    et al.
    Swedish Transport Administration, Trafikverket Luleå.
    Khan, Saad Ahmed
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nordmark, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Improved wheel-rail system of Sweden’s iron ore line2017Ingår i: Proceedings of the 11th International Heavy Haul Association Conference (IHHA 2017), Cape Town, South Africa, 2–6 September 2017 / [ed] P.J. (Hannes) Gräbe, R.D. Fröhling, 2017, s. 759-766Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    ABSTRACT: The Swedish Iron Ore Line (IOL) is the only heavy haul line in Europe. The northern part of the line is located above the Arctic Circle, a very harsh climate. Because of the introduction of new vehicles with a 30-tonnes axle load, the track were gradually replaced between 2006 and 2009 with heavier rails, mostly with a steel grade of R350LHT. Just after the first replacement of track in 2006, the project presented herein was established with the primary goal of improving the life length of the rail, and monitoring activities started. This project now has a unique database of rail degradation data. So far, the information has been used to improve the performance of the wheel-rail system and thus extend the life length of the rail, as well as to improve our knowledge of heavy haul operations in a cold climate. The paper discusses the project progress in general and gives some examples of improvements that have been successfully implemented, such as new rail profiles and a higher grinding frequency. Finally, it discusses the challenges of future capacity improvements, such as an increase in the axle load, and how these can be addressed.

  • 95.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson, Dan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Inspection of railway turnouts using camera2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The railway turnout is an essential component in a railway system, used to divert traffic along different tracks. A turnout includes a number of different parts, including the switch blade, frog, point machine, switch roller, soleplate, check rail, wing rail, drive rods, control rods and other bars. These parts must be kept in good condition, meeting functional and safety requirements. Failing to comply will result in a reduction of the network’s capacity with economic consequences. Not honouring the safety limits could result in severe accidents, including derailment, causing human casualties. By performing the right type of inspection and/or maintenance at the right time, these unwanted events can be reduced. To determine if and when a maintenance action should be performed, the condition of the turnout must be established, usually by manual inspections or with measurement vehicles. The drawback is the discrete nature of these inspection events. Failure modes with development times shorter than the inspection interval could result in a malfunction of the unit. An on-line measurement system would be able to deal with these failure events and initiate correct maintenance actions at an earlier stage. With an on-line system, remotely located turnouts could be inspected without on-site personnel. Capacity consuming failures of turnouts with a strategic location or with bottleneck characteristics could also be corrected before they affect traffic. This paper describes a feasibility study of a camera based inspection system for turnouts and discusses the effect the method could have on system reliability and capacity.

  • 96.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lin, Janet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Evaluating the measurement capability of a wheel profile measurement system by using GR&R2016Ingår i: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 92, s. 19-27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. The results show that the measurements of the tread hollowing and flange slope are on an acceptable level, while those for the flange height and flange thickness have to be rejected as unacceptable. The action proposed to increase the quality of data on the flange height and flange thickness is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making.

  • 97.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lin, Janet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Assessment of the data quality of wayside wheel profile measurements2016Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 19, nr 3, s. 19-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To evaluate the behaviour and the condition of a railway wheel in relation to performance and safety criteria, the wheel profile can be measured. This can be achieved using manual methods or automatic systems mounted along the railway track. Such systems have the advantage that they can measure a vast number of profiles, enabling new possibilities of performing statistical analyses of the results and pinpointing bad wheels at an early stage. These wayside measurement systems are, however, subjected to different environmental conditions that can affect the data quality of the measurement. If one is to be able to use automatic wheel profile measurements, the data quality has to be controlled in order to facilitate maintenance decisions. This paper proposes a method for the data quality assessment of an automatic wayside condition monitoring system measuring railway rolling stock wheels. The purpose of the assessment method proposed in this paper is to validate individual wheel profile measurements to ensure the accuracy of the wheel profile measurement data and hence the following data analysis. The method consists of a check routine based on the paired t-test, which uses a hypothesis test to verify if the null hypotheses are true. The check routine compares measurements of passing wheels rolling to a certain destination with measurements of the same wheels returning from that destination. The routine of comparing measurements of the same wheel, which is performed by four sensors (one on each side of each rail), will ensure that the sensors generate the same data for the same sample. A case study is presented which shows how the method can detect a faulty setup of the measurement system and prevent incorrect interpretations of the data from different measurement units in the same system. The paper ends with a discussion and conclusions concerning the improvements that are presented.

  • 98.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lin, Janet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Enhancing the quality of data from a wheel profile measurement system: a proposed approach2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This investigation proposes a method for increasing the quality of data from an automatic condition monitoring system for railway rolling stock wheels, in order to assure the right data quality for further use of the data. The data quality improvement is used to ensure a higher reliability of the data analysis and to propose a new check routine to ensure that the sensors generate the same data for the same sample. A case study on field data shows how the data from different measurement setups differ for three of four measurements and why this check routine is needed. The paper ends with a discussion and conclusions concerning the improvements that are presented.

  • 99.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nordmark, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Gustafsson, Per
    Comparison of TOR lubrication systems on the iron ore line2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Iron Ore Line (IOL) is a 473 km long track section which is located in northern Sweden and northern Norway, and has been in operation since 1903. The northern part is located above the Arctic Circle. The IOL is mainly used to transport iron ore and pellets from the mines in Kiruna and Malmberget to Narvik Harbour (Norway) in the northwest and Luleå Harbour (Sweden) in the southeast. The track section on the Swedish side is owned by the Swedish Government and managed by Trafikverket (the Swedish Transport Administration), while the ore wagons are owned and managed by the freight operator (LKAB).The IOL has seen a considerable increase in the axle load and traffic volume recently. Due to the introduction of new vehicles with a 30-ton axle load, the rails were gradually replaced between 2006 and 2009 with heavier rails, generally with a steel grade of 350LHT. The rail and wheels suffer from rolling contact fatigue (RCF) due to high friction between the rail and wheel. To control the wheel-rail interface, wayside top-of-rail (TOR) lubrication can be used. The reliability of the TOR lubrication equipment and the lubricants in northern conditions has not been investigated, and the long-term maintenance support required for TOR lubrication is unknown to the infrastructure manager. Furthermore, can TOR lubrication reduce the rail and wheel maintenance costs? This project has been conducted through collaboration between the main operator (LKAB) and the infrastructure manager (Trafikverket); the costs have been shared and the results analysed in collaboration. This paper describes the test period of two years, using two different TOR lubrication systems in two different places on the IOL, one situated in the northern loop and one in the southern loop, each with different operational conditions. The paper shows the actual operational conditions for the pilot test locations, the friction value close to the systems, the rail forces during the test period and some results for the noise measurements. Furthermore, the paper includes the improvements of system resulting from the test operation, and ends with recommendations for the continued use of TOR lubrication on the IOL.

  • 100.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nordmark, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Gustafsson, Per
    Pallari, Robert
    Mining Technology R and D, LKAB Kiruna Mine.
    Larsson, Dan
    Damill AB, Luleå, Damill AB.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Slutrapport avseende hjulprofilmätare i Sunderbyn2014Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Bakgrunden till projektets genomförande har varit den ökande mängden rälsbyten och mängden trafik med 30 tons axellast på Malmbanan. Spårunderhållet och hjulunderhållet har idag de överlägset högsta underhållskostnaderna av järnvägens olika system. Hjulprofilmätaren sågs som en möjlighet att kunna plocka ut de hjul som närmade sig underhållsgränserna för slitage, och därigenom kunna styra underhållet mer kostnadseffektivt.LKAB och Trafikverket enades därför att sätta upp ett gemensamt projekt där en ny typ av mätutrustning utprovades. För att få stöd med datalagring, bearbetning av data mm anlitades LTU och eMaintenanceLAB. Syftet med projektet har varit att undersöka och verifiera att en utrustning för automatisk hjulprofilmätning kan klara av att registrera och larma vid hjulpassager som avviker från de säkerhetsgränser och underhållsgränser som definieras i projektet med hänsyn till vårt klimat och våra förhållanden på Malmbanan. Den bärande idén i detta projekt har varit att man genom en kontinuerlig mätning av hjulprofiler ska kunna ta ut fordon ur trafik innan den avvikande hjulprofilen ger upphov till ett accelererande hjul- och rälslitage och därigenom sänka underhållskostnaden och öka livslängden på både hjul och räl. Projektet har även lett till en högre säkerhet på spåret då man kan mäta hjul som passerat säkerhetsgränsen för hjulparametrar och plockar bort dem, detta var inte var möjligt tidigare. De slutsatser som kan dras från detta projekt är följande:• Utvecklingsprojekt kan med fördel genomföras gemensamt mellan industri, infrastrukturförvaltare och akademi. • För att säkerställa ett bra resultat är det viktigt att genomföra alla steg i ett projekt från koncept till överlämnande. Som stöd för detta har V-modellen används som representerar livscykeln för systemet enligt EN-50126.• Val av tekniklösning och leverantör har gjorts utifrån tekniknivå, referensanläggningar samt drift- och supportmöjlighet och inte enbart utifrån pris. Ett utvecklingsprojekt likt detta handlar inte primärt om att få en utrustning i drift utan överföring av ”know how” kring vilka möjligheter och begränsningar det finns med denna teknik.• Resursbehovet för test och utvärdering underskattades och gjorde att projektet försenades ett år jämfört med ursprunglig tidplan. • Informationen som genereras från denna utrustning är mycket användbar för alla parter som arbetar med utveckling av underhåll inom järnvägen. • Utmaningen för att tillgodogöra sig nyttan från mätstationen ligger i att kunna förädla och integrera de genererade tillståndsdata till respektive underhållsorganisation.

1234567 51 - 100 av 1463
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf