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  • 1.
    Al-Douri, Yamur K.
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Hamodi, Hussan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Time Series Forecasting using a Two-level Multi-objective Genetic Algorithm: A case study of cost data for tunnel fans2018Ingår i: Algorithms, E-ISSN 1999-4893, Vol. 11, nr 8, artikel-id 123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study is to develop a novel two-level multi-objective genetic algorithm (GA) to optimize time series forecasting data for fans used in road tunnels by the Swedish Transport Administration (Trafikverket). The first level is for the process of forecasting time series cost data, while the second level evaluates the forecasting. The first level implements either a multi-objective GA based on the ARIMA model or based on the dynamic regression model. The second level utilises a multi-objective GA based on different forecasting error rates to identify a proper forecasting. Our method is compared with the ARIMA model only. The results show the drawbacks of time series forecasting using the ARIMA model. In addition, the results of the two-level model show the drawbacks of forecasting using a multi-objective GA based on the dynamic regression model. A multi-objective GA based on the ARIMA model produces better forecasting results. In the second level, five forecasting accuracy functions help in selecting the best forecasting. Selecting a proper methodology for forecasting is based on the averages of the forecasted data, the historical data, the actual data and the polynomial trends. The forecasted data can be used for life cycle cost (LCC) analysis.

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  • 2.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, 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.

  • 3.
    Jönsson, Jens
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Arasteh Khouy, Iman
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Measurement of vertical geometry variations in railway turnouts exposed to different operating conditions2016Ingår 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. 486-501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Turnouts are critical units in a railway system; they perform the switching procedure that allows trains to change between routes. Monitoring the track geometry of a turnout is necessary for maintenance planning and design optimisation. Monitoring is usually done by track recording cars, however, to isolate the ageing and dynamic behaviour of the track it is also necessary to study the unstressed track geometry of the turnouts. Such measurements can be used to develop degradation models to optimise maintenance and design, thereby increasing availability and reducing life cycle cost. This paper introduces a new method to measure the vertical position of the track geometry over time during non-operational conditions (unstressed) to show track degradation. The new method includes a smart system that uses relative measurement reference points to create a better accuracy and lower costs compared with fixed reference points. It evaluates various types of measurement equipment and uses levelling equipment to measure the unstressed vertical geometry of 13 turnouts located on Swedish railway lines, with three follow-up measurements over a year and a half. The turnouts were categorised into four groups: based on their accumulated capacity in million gross tonnes (MGT) and whether they were on a straight or curved main track. Surprisingly, the first three measurements showed the geometry of turnouts on the straight main track to have a vertical elevation tendency towards the mid-section, whereas the turnouts on the curved main track had a general vertical downwards bend tendency towards the mid-section. The results also showed that a higher capacity in MGT has a greater influence on track geometry changes over time.

  • 4.
    Lemma, Yonas
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Asplund, Matthias
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Top-of-Rail Friction Measurements of the Swedish Iron Ore Line2014Ingår 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. 3-7Konferensbidrag (Refereegranskat)
    Abstract [en]

    Friction management in the railway industry is a well-establishedtechnology with the aim of optimizing the friction between wheeland rail. Determining the friction coefficient (Q) at the wheel-railinterface is therefore important especially for heavy haul lineswith higher axel loads. This paper presents an initial study of thetop-of-rail friction condition of a 30 ton axel load, Iron Ore line inthe northern part of Sweden. The friction coefficient between therail and a metal wheel of a portable Tribometer was measured atdifferent geographical locations and during differentenvironmental conditions. The effects of precipitation are studiedand compared with the effects of top of rail friction modifiers. Themeasurements of not lubricated line sections showed valuesaround Q 0.6 compared to Q 0.3 for areas with e.g. top-of- raillubrication. During snowy conditions a decrease in friction couldalso be detected.

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  • 5.
    Lundberg, Jan
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Wanhainen, Christina
    Luleå tekniska universitet, Geovetenskap och miljöteknik.
    Casselgren, Johan
    Luleå tekniska universitet, Strömningslära och experimentell mekanik.
    Measurements of friction coefficients between rails lubricated with a friction modifier and the wheels of an IORE locomotive during real working conditions2015Ingår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 324-325, s. 109-117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The real friction coefficients between the rails and the wheels on a 360. t and 10,800. kW IORE locomotive were measured using the locomotive[U+05F3]s in-built traction force measurement system. The locomotive consisted of two pair-connected locomotives had a CoCo+CoCo bogie configuration, and hauled a fully loaded set of 68 ore wagons (120. t/wagon). The measurements were performed both on rails in a dry condition and on rails lubricated with a water-based top-of-rail (ToR) friction modifier on the Iron Ore Line between the cities of Kiruna and Narvik in Northern Sweden and Norway, respectively. Since full-scale measurements like these are costly, the friction coefficients were also measured at the same time and place using a conventional hand-operated tribometer, with and without the ToR friction modifier. The most important results are that the real friction coefficient is definitely not constant and is surprisingly low (0.10-0.25) when the ToR friction modifier is used, and that it is also significantly dependent on the amount of ToR friction modifier. A large amount will reduce the friction coefficient. Furthermore, it is concluded that the real friction coefficients are in general lower than the friction coefficients measured with the hand-operated tribometer. A final remark is thus that the use of a water-based ToR friction modifier can give excessively low friction, which can result in unacceptably long braking distances.

  • 6.
    Petersson, Anna Malou
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    The Impact of Competitive Tendering on Railway Maintenance Performance in Sweden2014Ingår i: Proceedings of the Second International Conference on Railway Technology: research, development and maintenance ; 8 - 11 April 2014, Ajaccio, Corsica, France / [ed] J. Pombo, Kippen: Civil-Comp Press , 2014, artikel-id 290Konferensbidrag (Refereegranskat)
  • 7.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Parida, Aditya
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Drift, underhåll och akustik.
    Development of an integrity index for benchmarking and monitoring rail infrastructure: application of composite indicators2015Ingår i: International Journal of Rail transportation, ISSN 2324-8378, E-ISSN 2324-8386, Vol. 3, nr 2, s. 61-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Railways are large, geographically dispersed assets, consisting of numerous systems, subsystems and components, for which considerable amounts of data and numerous indicators are generated for monitoring their operation and maintenance. Proper assessment of operation and maintenance performance is essential for sustainable and competitive rail transportation. Composite indicators (CIs), or indices, can simplify the performance measurement by summarising the overall performance of a complex asset into a single figure, making it easier to interpret than multiple indicators and plots. In this article, a CI termed ‘rail infrastructure integrity index’ is developed and verified in a case study. The results show that CIs can be used for benchmarking and assessing the overall performance of railway sections in a single figure, indicating which sections need further study. Their implementation should allow data users to do sensitivity analysis and decomposition for traceability.Keywords: rail infrastructure; composite indicator; integrity index; dependability; RAMS; benchmarking

1 - 7 av 7
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