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  • 1.
    Ahmadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Garmabaki, Amir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ghodrati, Behzad
    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.
    Optimum inspection interval for hidden functions during extended life2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 3, s. 45-49Artikel i tidskrift (Refereegranskat)
  • 2.
    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%.

  • 3.
    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)
  • 4.
    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.

  • 5.
    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.

  • 6.
    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.

  • 7.
    Berglund, Filip
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nordström, Jakob
    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.
    Non-destructive testing (NDT) methods for detection and monitoring of fatigue cracks in mining mills2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 2, s. 18-26Artikel i tidskrift (Refereegranskat)
  • 8.
    Bergquist, Bjarne
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Control Charts supporting Condition-Based Maintenance of Linear Railway Infrastructure Assets2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 2, s. 7-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 9.
    Dandotiya, Rajiv
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wijaya, Andi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Evaluation of abrasive wear measurement devices of mill liners2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 2, s. 3-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurement of the liner wear in the mill of an ore dressing plant is one of the critical parameters in the context of mill downtime and production performance. The total downtime cost during measurement can be reduced by a significant fraction by using appropriate measurement devices. Due to the different quality attributes of a measuring device, e.g. the cost, accuracy, reliability and accessibility, it is necessary to select an appropriate device based on the specific needs of the industry. The main aim of this study is to determine a unified measure or quality index for the service quality of the measurement device across selected attributes. Each quality index will then correspond to the total predicted usability of the particular measurement method based on the industry needs. Furthermore, this study includes test of selected measurement methods and discusses the advantages and disadvantages for the same. It also proposes a new concept of an indirect measurement method to reduce the downtime during inspection.

  • 10.
    Enochsson, Ola
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Täljsten, Björn
    Paulsson, B.
    Sustainable railway bridges with higher axle loads: monitoring examples from northern Sweden2009Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, nr 2, s. 39-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Monitoring of several railway bridges has been carried out in northern Sweden in order to increase the allowable axle load. The work is part of a European Integrated Project "Sustainable Bridges - Assessment for Future Traffic Demands and Longer Lives", 2003 - 2008. This paper describes the project and gives some examples of applications.

  • 11.
    Famurewa, Stephen Mayowa
    et al.
    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.
    Application of Maintenance Performance Measurement for Continuous Improvement in Railway Infrastructure Management2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 1, s. 49-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Railway transport infrastructure is a linearly distributed asset that requires an effective performance management system to meet sectional and overall business objectives. In particular, an effective performance measurement system with relevant analysis technique in an ongoing manner is necessary to facilitate continuous improvement. Maintenance performance measurement (MPM) is essential to quantify the impact of past maintenance decisions and actions and also to support new decisions. This article presents the challenges of implementing and using MPM systems for maintenance decisions in the railway industry. Thereafter, a risk matrix with maintenance performance indicators is introduced as a complementary analysis tool to identify weak links on a railway line. A case study of a section on the heavy haul line of the Swedish Transport Administration railway network is presented to demonstrate the application of the risk matrix tool for continuous improvement. The results identified the bottlenecks on the line section, which are improvement opportunities for maintenance performance in terms of service quality and capacity target of the infrastructure manager

  • 12.
    Fuqing, Yuan
    et al.
    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.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Failure diagnosis of railway assets using support vector machine and ant colony optimization method2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 2, s. 3-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Support Vector Machine (SVM) is an excellent technique for pattern recognition. This paper uses a multi-class SVM as a classifier to solve a multi-class classification problem for fault diagnosis. As the pre-defined parameters in the SVM influence the performance of the classification, this paper uses the heuristic Ant Colony Optimization (ACO) algorithm to find the optimal parameters. This multi-class SVM and ACO are applied to the fault diagnosis of an electric motor used in a railway system. A case study illustrates how efficient the ACO is in finding the optimal parameters. By using the optimal parameters from the ACO, the accuracy of the performed diagnosis on the electric motor is found to be highest.

  • 13.
    Galar, Diego
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Fuqing, Yuan
    Department of Engineering and Safety, University of Tromsø, Tromsø, Norway.
    Harmonic and Inter-harmonic Analysis on Power Signal from Railway Traction Systems2017Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 20, nr 2, s. 3-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A thorough investigation of wave velocity effects to the accuracy of damage location in a two dimensional source location algorithm of acoustic emission technique was carried out with pencil lead breaks (PLB) tests on a steel plate (SS400). Several AE signal propagation modes were investigated along with the experimental averaging values of wave velocity. Results show that the appropriate consideration of velocity mode in damage location is an important factor in reducing the errors of damage source location in acoustic emission technique.

  • 14.
    Galar, Diego
    et al.
    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.
    Lee, Jay
    Center for Intelligent Maintenance Systems (IMS), Cincinnati, OH.
    Zhao, Wenyu
    Center for Intelligent Maintenance Systems (IMS), Cincinnati, OH.
    Remaining useful life estimation using time trajectory tracking and support vector machines2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 3, s. 2-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a novel RUL prediction method inspired by feature maps and SVM classifiers is proposed. The historical instances of a system with life-time condition data are used to create a classification by SVM hyper planes. To test the system's RUL, degradation speed is evaluated by computing the minimal distance based on the degradation trajectories, i.e. the approach of the system to the hyper plane that segregates good and bad condition data on a different time horizon. The final RUL of a specific component can be estimated and global RUL information can be obtained by aggregating the multiple RUL estimations using a density estimation method

  • 15.
    Ghodrati, Behzad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Markeset, Tore
    Centre for Industrial Asset Management, University of Stavanger.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Enhancement of mining machineries performance through supportability2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 2, s. 35-43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cost analysis of mining operations in general shows that 30 to 50 percent of direct mining costs are related to maintenance and losses related to lost production during equipment downtime. To reduce these losses one first needs to improve the equipment reliability and thereafter to reduce the downtime losses through improved maintainability and supportability. The mining operational environment is often harsh and may severely impact all three of these abilities. In this paper we focus on how to improve the estimation of spare parts by taking into account the operating environment in the estimation models. By having better models to predict spare parts needs, one can avoid logistics delays and thereby reduce downtime. In this study we develop an improved statistical-reliability (S-R) analysis approach that take into account the system/ machine operating environment. The analysis approach is multiple regressions based on Cox’s proportional hazards modeling (PHM). Subsequently, in a case study, the management of the spare parts inventory based on the economic order quantity and required performance of the product is addressed.

  • 16. Granström, Rikard
    et al.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring of railway wheels and no fault found problems2009Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, nr 2, s. 46-53Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Defective railway wheels can cause severe damages to both track and vehicle items, which in worst case can lead to derailments with extensive losses. Wheel impact detection systems are intended to support prevention of railway damages and its related losses, through recognition of wheel defects and generation of alarms. While commissioning of a wheel impact detection system in Sweden, it was revealed that the detection system was reliable as they were not generating any false alarms. However, during operation some of the system's alarms resulted in No Fault Found (NFF) events. Hence an investigation was launched to determine if the cause of the NFF events were false alarms generated by the detection system, or the inability of subsequent manual inspection to replicate the detection system's test result. This paper presents experiences from the verification study and links these to international experiences illustrating how wheel impact detection systems can support continuous assessment of wheel condition and related condition based maintenance efforts.

  • 17.
    Hannu, Jesper
    et al.
    Luleå tekniska universitet.
    Rhen, Mats
    Luleå tekniska universitet.
    Time dependent stress-strength model for a pitch link in a hydropower unit2003Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 6, nr 4, s. 3-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When Choosing between replacement and reinvestment alternatives, decisions are based upon economic, safety and ecological constraints. Reliability models to predict the risk of future failure is one way to improve the decision guidance document. In this paper the probability of failure for a pitch-ink in a kaplan hub has been investigated with respect to number of load cycles the link been exposed to. The failure reliability model is based on basic design variables, e.g. material properties, load tolerances etc. and the probability density functions of these variables. From this the probability of failure is computed following statistical methods. Physics-based reliability models are a possible way to determine the probability of failure for hydropower components. These models will give an estimation of how different operation in a design variables affect life expectancy.

  • 18.
    Holmgren, Mattias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A process approach to maintenance-related hazard identification2008Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 11, nr 1, s. 36-46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    History has shown that maintenance contributes to incidents and accidents with extensive losses. The purpose of this paper is to describe a process approach for maintenance-related hazard identification, in order to support continuous risk reduction in maintenance activities. The proposed maintenance process model has been applied within a study of maintenance execution of DC-motors in paper-mills. However, both the model and the findings from its application are believed to be transferable to the maintenance of other critical technical systems. A recurring hazard is insufficient feedback. Hence, proper feedback may help to reduce risk. Further findings indicate that incidents manifested during execution may be due to hazards in other process phases. The maintenance of complex and critical systems is also affected by the work environment and knowledge of technicians, whose requirements should be fulfilled through appropriate organisational and technical support.

  • 19. Karim, Ramin
    et al.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    eMaintenance readiness of Swedish process industry: a case study2010Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 13, nr 3, s. 18-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The business scenario is focusing more on e-business intelligence to perform transaction with customers needs for enhanced value and improvement in asset management. Such prognostic business requirement is compelling the organizations to minimize the production and service downtime by reducing the machine performance degradation. The purpose of this paper is to undertake a mapping of the present status of the maintenance of the Swedish process industry, study their linkage and correlation between the business and maintenance processes, and the supporting Information & Communication Technology (ICT), in order to identify the feasibilities and challenges for implementing eMaintenance system. The focus of the work was to identify how the current maintenance process is defined, organized and performed; and how it is linked and correlated to the business and support processes and besides what is executed within the maintenance process.

  • 20.
    Larsson, Dan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Classification of railway vehicles and their contribution to the track degradation2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 4, s. 35-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a method to use real time force data from enhanced wayside monitoring stations to classify railway vehicles contribution to the overall track degradation. The major advantage of doing so compared to classifications based on theoretic simulation only is that the vehicle maintenance conditions can be automatically taken into account. A potential use of the classification is to adjust track access charges according to the real state of each operator's fleet. Operators with well-maintained vehicles shown by measured low impact on track could then be favoured on, i.e., yearly updates of the fee. The paper gives three examples of three different train types and how they can be compared.

  • 21.
    Larsson, Dan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Enhanced condition monitoring of railway vehicles using rail-mounted sensors2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 2, s. 17-25Artikel i tidskrift (Refereegranskat)
  • 22.
    Lemma, Yonas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Asplund, Matthias
    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.
    Investigation of the Top-of-Rail Friction by Field Measurements on Swedish Iron Ore Line2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 2, s. 17-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Friction management in the railway industry is a well-established technology with the aim of optimizing the friction between the wheel and rail. Determining the friction coefficient (μ) at the wheel-rail interface is therefore important especially for heavy haul lines with higher axle loads. This paper presents an initial study of the top-of-rail friction condition of a line with 30 ton axle load, the Iron Ore Line in the northern part of Sweden. The friction coefficient between the rail and the metal wheel of a portable tribometer was measured at different geographical locations and in different environmental conditions. The effects of precipitation are studied and compared with the effects of top-of-rail friction modifiers.The measurements of non-lubricated line sections showed values of μ≈0.6, compared to μ≈0.3 for areas with, for example, top-of- rail lubrication. In snowy conditions a decrease in friction could also be detected.Keywords: Friction management, Friction measurement, Friction modifier, Heavy haul railway line, Swedish Iron Ore Line.

  • 23.
    Liyanage, Jayantha P.
    et al.
    Stavanger University College.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A global framework to manage operations and maintenance (O and M) performance to condition plant health: reflections from the Norwegian oil and gas industry2004Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 7, nr 1, s. 39-44Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Effective management of operations and maintenance performance has a significant impact on the management of oil and gas production assets. Apparently, its organization wide implications are much wider in reality than in classical cost centered views in the current oil and gas business environment. Oil and gas producers today are much keen on understanding the business impact of operations and maintenance process, but seemingly the underlying subject matter has not been fully explored and understood yet. In this paper we attempt to shed some light in this endeavor by exploring the significance of operations and maintenance performance in the current oil and gas business environment from a different viewpoint. Here we advocate that to meaningfully illustrate how operations and maintenance performance makes good business sense, the ideal point of departure is the overall value proposition of the business. Accordingly, we, elaborate how this value proposition should be brought into perspectives within production asset and operations and maintenance performance. The underlying aim is to develop a priori performance model that in turn lead to development of performance assessment systems. Elaborations in this paper are based on our observations, learning and experience within the Norwegian petroleum industry.

  • 24.
    Martin del Campo Barraza, Sergio
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Unsupervised feature learning for rotating machineryIngår i: International Journal of COMADEM, ISSN 1363-7681Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    A smart sensorized bearing can be described as a bearing with built-in sensors for condition monitoring. These bearings require new methods for the processing of the information coming from the sensors. Smart bearings are expected to become the central components in the condition monitoring sensor system of future rotating machines. Condition monitoring typically requires expert knowledge about the machine that is monitored, making it costly to adapt the methods to the different machines, environment and operational conditions. This approach deals with an unsupervised learning method that allows for automatic characterization of signals with repeating structure in the time domain. The method is sparse coding with dictionary learning. We present the information obtained from time domain and frequency domain techniques and describe the conditions required to make the fault diagnosis possible. In contrast, we describe how our approach can autonomously depict deviations from the normal state of operation of machine by monitoring a dictionary of atomic waveforms learned from a signal. We study the propagation over time of a learned dictionary when the vibration of a rotating machine is monitored in normal and faulty states of operation, and we find that the adaptation rates of some atomic waveforms change significantly when a fault occurs.

  • 25.
    Modiri, Bahman
    et al.
    Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran.
    Pourgol-Mohammad, Mohammad
    Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran.
    Yazdani, Mojtaba
    Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran.
    Salimi, Hossein
    Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran.
    Salehpour-Oskouei, Farzin
    Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stochastic lifetime estimation of pressurized gas pipeline: Case study of the urban gas pipeline2017Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 20, nr 2, s. 31-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrosion is a major contributor in gas pipeline degradation and failure. Due to significant sources of uncertainties in corrosion progression modelling, nondeterministicapproaches are more promising in recent researches. Several researches were conducted about probabilistic assessment of corrosion and itseffects in practical models. However, in these studies, either internal or external corrosion individually were separately evaluated, without taking intoaccount their correlated effects. In this study, a reliability analysis method is proposed for pressurized bare gas pipeline buried in soil by taking into accountboth corrosion effects from inside and the outside of the pipe. Environment effects are also studied on pipe’s corrosion by considering different soil types. Itwas observed that soil grain size has significant impact in corrosion occurrence. Consequently, sandy clay loam has the highest reliability index while clayand clay loam have the lowest values among these soil types.

  • 26.
    Morant, Amparo
    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.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Dependability improvement through configuration management: A study of railway signalling systems2013Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 16, nr 4, s. 31-40, artikel-id 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reliability, maintainability and related maintenance support of signalling systems affect the railway network´s availability. Constituting a system-of-systems spread over a wide geographical area, signalling systems consist of a large number of items with different lifecycles making it a challenge to define and describe the structure and relationship between the system’s inherent items at any specific time. System configuration describes a system’s structure to which other data sources can be related. Some current research discusses asset maintenance management in the railway infrastructure, but not many holistic approach deals with signalling systems. The purpose of this paper is to investigate how the process of configuration management, can improve the dependability of the railway system. The paper presents a model for the configuration management of railway signalling systems. The model is based on the results of company surveys and interviews, data analysis and literature review. This model provides better control and visibility of the information related to the system and any changes made to it. Faster and better failure diagnostics can be performed, thus improving maintenance performance. This, in turn, provides better availability of the system by reducing the downtime of the railway network; hence, an improvement in maintainability is also achieved.

  • 27. Niska, Stefan
    et al.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nyström, Birre
    Causes of EMC disturbance on the railway: a study of recurring faults in the signal box at Oxmyran station in Sweden2009Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, nr 2, s. 20-29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Failure reporting systems in the railway industry are reliant on correct reporting into the system, so that the right information may be send back to the user. This information is needed for correct decision-making in the maintenance process. For failure due to electromagnetic disturbance a correct classification can be very difficult to make in the field, with limited time available for the analysis of failure causes. The Swedish Railway Administration (Banverket) has a problem in a signal box at Oxmyran Station, where faults are reported frequently. The wide variation in the reported causes of the disturbance of the electromagnetic compatibility makes it very difficult to pinpoint the real causes of the events that lead to failure. In this paper, a large number of causes are investigated, discussed and dismissed as reasons for the large number of faults at Oxmyran. Measurements on site, however, show that the electromagnetic interference is much higher at Oxmyran than at the reference station at Ore Alv. The main purpose of this study was to investigate the probable source and the subsequent sequence of events that result in faults that break the RC circuit at Oxmyran.

  • 28.
    Nissen, Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    LCC analysis for switches and crossings: a case study from the Swedish Railway Network2009Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, nr 2, s. 10-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper makes an attempt to analyze the LCC values of switches and crossings (S&C) on Swedish Railway Track. The scope of the paper is to explore the possibility of using LCC as a decision tool for an infrastructure manager. The S & C cost from the Swedish Rail Administration (Banverket) were collected for the LCC analysis as a part of the case study. A cost model based on the acquisition phase and the operation and maintenance phase has been developed and tested. In this model the LCC values of three types of S & Cs are compared. The model can also be used to find cost drivers, as well as to perform sensitivity analysis to find parameters that have a large influence on the result. The model has been built with the assumption that a multiple type of maintenance action is undertaken for each subsystem. Within the model, there is a possibility of defining periodical maintenance intervals besides the annual maintenance cost. The LCC value may be presented as an annuity cost, which enables a comparison between assets that have different technical lifetimes.

  • 29. Nissen, Arne
    et al.
    Parida, Aditya
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring of railway switches and crossing by using data from track recording cars2010Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 13, nr 3, s. 36-40Artikel i tidskrift (Refereegranskat)
  • 30.
    Palo, Mikael
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindsund, Isabelle
    Luleå tekniska universitet.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A case study on railway wheel maintenance management with several layers of contractors2013Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 16, nr 4, s. 5-12Artikel i tidskrift (Refereegranskat)
  • 31.
    Palo, Mikael
    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.
    Condition monitoring of wheel wear on iron ore wagons2012Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 15, nr 2, s. 26-33Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Keeping wheel profiles in an acceptable condition is a major concern for both railway operators and infrastructure owners. The condition of the wheels influences both their wear and the required rail maintenance. Wheel wear affects the dynamic characteristics of vehicles and the dynamic force impact on the rail and, in a worst case scenario, can cause derailment. This paper studies the correlation of wear rate and wheel force to temperature and seasonal differences, monitoring eight identical wheel axles of different ages for a full life cycle. The study notes differences in wheel wear and wheel/rail forces while operating with a 30 ton axle load and in temperatures ranging from -30°C to +30°C. It measures speed, vertical and lateral forces for every train passage and calculates the lateral-to-vertical force ratio at a research station near Luleå, Sweden. The study concludes that wheel wear is significantly greater at lower temperatures. The magnitude and variation of lateral forces are strongly dependent on the bogie position, with the highest peak value recorded for the leading low rail. The L/V ratio is strongly seasonally dependent with large differences within a month due to changes in friction.

  • 32.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring and maintenance performance assessment issues for mining industry2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 2, s. 27-34Artikel i tidskrift (Refereegranskat)
  • 33.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Maintenance performance measurement system: application of ICT and e-maintenance concepts2006Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 9, nr 4, s. 30-34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With emergence of intelligent sensors to measure and monitor the health state of the components and implementation of information and communication technologies (ICT), conceptualization and implementation of e-Maintenance is becoming a reality. e-Maintenance facilitates decision making in real time by monitoring plant and systems health and its behaviour in real time, benchmarking the status against the specified standards and by evaluating the associated business risks with various alternatives at hand by using embedded intelligent sensors internet and technology. To benchmark the health state and the performance characteristics invariably different types of performance trend charts and indicators are envisioned to be generated and implemented for use by the experts while making decisions in maintenance. Though, e-Maintenance shows a lot of promise, seamless integration of ICT into the industrial environment and setting, remains a challenge. In this paper, the author argues that understanding the requirements and constraints from maintenance performance and ICT perspective is essential for effective implementation of such concepts. The related issues are needed to be addressed for successful use of ICT and e-Maintenance for measuring maintenance performance. The paper discusses the concepts of e-Maintenance and is based on experiences gained through an ongoing project in this area and examines its applicability for

  • 34.
    Parida, Aditya
    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.
    Condition Monitoring and Diagnosis of Modern Dynamic Complex Systems using Criticality aspect of Key Performance Indicators2017Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 20, nr 1, s. 35-39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Proactive condition monitoring, diagnosis and prognosis of modern complex engineering systems are becoming an increasingly challenging issue. This is mainly attributed to the dynamic global scenario and the ever increasing stakeholders conflicting interests. One of the most important missing links that is often given a low priority while assessing the health of a complex dynamic system is the key criticality of the system in question. This paper discusses some of the challenging issues facing the Asset Management personnel and highlights the importance of incorporating criticality aspect of the key performance indicator in the diagnosis and prognosis of all modern complex systems.

  • 35.
    Pourgol-Mohammad, Mohammad
    et al.
    Department of Mechanical Engineering, Sahand University of Technology, Tabriz, Iran.
    Makarachi, Peymaan
    School of Engineering- Emerging Technologies, Tabriz University, Tabriz, Iran.
    Soleimani, Morteza
    School of Engineering- Emerging Technologies, Tabriz University, Tabriz, Iran.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability Enhancement of Centrifugal Pumps by Multi-Objective Genetic Algorithm Optimization2017Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 20, nr 2, s. 23-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this research, a methodology is presented to optimize the life performance of mechanical systems using multiple objective evolutionary algorithm. Conflicting objectives are encountered (e.g. low costs and longer service life) here along with significant number of constraints (e.g. technological limitations, weight and volume). To solve the design optimization problems, the objective function is weighted with a combination of the targets. The evolutionary algorithm (i.e. GA) is applied for minimization of the system failure rates, reliability allocation optimization. The failure rates are optimally estimated for the system?s critical components. Reliability allocation technique is utilized to determine the optimum reliability of the constituent components with higher failure rates. The reliability targets are determined for the components through the minimized failure rates. The methodology is demonstrated through a case study, on a centrifugal pump. The pump design requires consideration of several targets and requirements with different weight factors for satisfaction (e.g., availability, capability, efficiency and weight) along the pump life. Analytical Hierarchy Process (AHP) is utilized to determine the weights of the objectives. As a result of this research, the equipment design is improved, costly over-designs options are prevented and development tests are optimized.

  • 36.
    Schunnesson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Kristoffersson, Thomas
    Rock mass characterisation using drill and crushability monitoring: A case study2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 2, s. 44-52Artikel i tidskrift (Refereegranskat)
  • 37.
    Schunnesson, Håkan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Mwagalanyi, Hannington
    Luleå University of Technology.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Shovel teeth monitoring and maintenance in open-pit mines2011Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 14, nr 1, s. 3-10Artikel i tidskrift (Refereegranskat)
  • 38.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Al-Jumaili, Mustafa
    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.
    Natural language processing of maintenance records data2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 2, s. 33-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Enterprise resource planning systems and maintenance management systems are commonly used by organisations for handling of maintenance records, through a graphical user interface. A maintenance record consists of a number of data fields, such as drop-down lists, list boxes, check boxes and text entry fields. In contrast to the other data fields, the operator has the freedom to type in any text in the text entry fields, to complement and make the maintenance record as complete as possible. Accordingly, the text entry fields of maintenance records can contain any words, in any number.Data quality is crucial in statistical analysis of maintenance records, and therefore manual analysis of maintenance records’ text entry fields is often necessary before any decision making. However, this may be a very tedious and resource consuming process.In this article, natural language processing is applied to text entry fields of maintenance records in a case study, to show how it can bring further value in the assessment of technical assets’ performance.Keywords: Maintenance records, Natural language processing, Structured and unstructured data, Data quality, Rail infrastructure.

  • 39.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A requirements management approach supporting integrated health management systems design2006Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 9, nr 2, s. 2-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    System health management is an approach that is intended to improve the dependability and safety of technical systems, and to decrease the combined cost of operation and support. In order to achieve the potential benefits of Health management, it is necessary to combine stakeholder requirements with a thorough engineering knowledge. The aim of this paper is to present a systemic, systematic, and stakeholder-centred Requirements Management approach that supports the design of Integrated Health Management System (IHMS). A holistic management model intended to increase stakeholder satisfaction with a reduced amount of resources in also presented. This approach is applied to a case-study related to a modern combat aircraft, which is a highly complex and critical technical system

  • 40.
    Tretten, Phillip
    et al.
    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.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Candell, Olov
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Guest editorial2015Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, nr 2, s. 5-6Artikel i tidskrift (Övrigt vetenskapligt)
  • 41.
    Zhang, Bo
    et al.
    Infrastructure Inspection Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing, China.
    Liu, Xiubo
    Infrastructure Inspection Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing, China.
    Lin, Jing
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Identification of span of Multi-span Simply Supported Girders by the Longitudinal Level Waveforms2019Ingår i: International Journal of COMADEM, ISSN 1363-7681, Vol. 22, nr 3, s. 19-22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In high-speed railways, the periodic component of longitudinal level on the top surface of the track can be observed for multi-span simply supported girders. To monitor this component, the paper proposes a method to determine the locating position of simply supported girders using longitudinal level waveforms. The method first applies time-frequency analysis to determine the locating position of simply supported girder bridges in the longitudinal level waveform. Then it adopts a local minimum detection strategy to identify the locating position of the girders. The method is evaluated using the longitudinal level data of a 100km high-speed railway in China; the results show good locating performance.

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