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  • 1. Andersson, Anders
    et al.
    Holmsten, Magnus
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Mätteknik för processindustrin2017 (ed. 5)Book (Other academic)
    Abstract [sv]

    Hur varmt är det i tanken? Vilket tryck ger pumpen? Det är två exempel på frågor som kan besvaras med processmätteknik.Att mäta är att veta, sägs det, men det gäller ocksåatt veta hur bra man mäter! Felaktiga mätresultat skaparproblem, osäkerhet och kan rent av vara farliga.I den här boken får du hjälp att undvika mätfel, du fårlära dig om olika mätprinciper och hur mätare av olika slagbäst används och monteras. Främst handlar det om temperatur,tryck, flöde och nivå men även annat som finns i enprocessindustri. Du får kunskap om kalibrering, spårbarhetoch mätosäkerhet, och samtidigt om saker runt omkringmätinstrumenten, till exempel CE-märkning, elstörningar,explosionsskydd, skrivregler, signalöverföring, standardermed mera

    Innehållsförteckning:  1: Mätteknik 2: Lästips – Gör så här 3: Mått i historien 4: CE-märkning 5: SI-systemet 6 :Signalöverföring 7: Säkerhet 8: Mätosäkerhet A 9: Fysik och matematik 10: Mättekniska begrepp 11: Temperaturmätning 12: Tryckmätning 13: Flödesmätning 14:Nivåmätning 15: Värmemätning 16: Vakter och larm 17:Serviceinstrument 18:Konduktivitetsmätning 19: pH-mätning 20: Densitetsmätning 21: Vägning 22: Fuktmätning 23: Mätosäkerhet B 24: Kalibrering 25: Pumpar och ventiler 26: Rörledningar 27: Mätosäkerhet C 28: Tabeller 29:Index

  • 2.
    Arrhenius, Karine
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Karlsson, Anders
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Hakonen, Aron
    Ohlson, Lars
    Fordonsgas Sverige AB, Sweden.
    Yaghooby, Haleh
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Büker, Oliver
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Variations of fuel composition during storage at Liquefied Natural Gas refuelling stations2018In: Journal of Natural Gas Science and Engineering, ISSN 1875-5100, E-ISSN 2212-3865, Vol. 49, p. 317-323Article in journal (Refereed)
    Abstract [en]

    Liquefied Natural Gas (LNG) and Liquefied Biogas (LBG) utilization within the heavy duty transport sector is today a sustainable alternative to the use of oil. However, in spite of the high degree of insulation in the storage tank walls, it is impossible to fully avoid any net heat input from the surroundings. Due to some degree of vaporization this results in variation in gas composition during storage at refuelling stations, potentially leading to engine failures. Within this study, a vaporizer/sampler has been built and tested at a station delivering liquefied biomethane (LBG) and occasionally; such in this case, LNG to heavy and medium duty trucks. The vaporizer/sampler has then been used to study the variation of the LNG composition in the storage tank during a two weeks period. The results clearly underline a correlation between the gas phase and the liquid phase as the concentration changes follow the same trend in both phases. Two opposite effects are assumed to influence the concentration of methane, ethane and propane in the liquid and in the gas phase. On one hand, because of the probable presence of not fully mixed layers in the storage tank and due to vehicles being refuelled, both liquid and gas phases are enriched in methane at the expense of ethane and propane. On the other hand, due to boil-off effect towards the end of the storage period, both liquid and gas phases are enriched in ethane and propane at the expense of methane.

  • 3.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Absolute calibration of a 100 KV DC divider1996Conference paper (Refereed)
    Abstract [en]

    An absolute determination of the ratio of a 100 kV DC divider has been made. A new Zener device that has recently become available has been used in a step-up mode to obtain the divider ratio. The uncertainty of the determination is 5.5 ppm.

  • 4.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Achievable Accuracy in Industrial Measurement of Dissipation Factor of Power Capacitors2018In: NCSLI Measure, ISSN 1931-5775, Vol. 12, no 1, p. 34-41Article in journal (Refereed)
    Abstract [en]

    Modern dielectrics used in power capacitors can exhibit a dissipation factor lower than 0.005 %, which approaches the limits of presently available measurement techniques. This article reviews techniques, apparatus, and available calibration services for dissipation factor with regard to lowest achievable uncertainties. It is shown that further metrological advances are necessary to lower uncertainty in the measurement to levels at least five times less than presently achievable, in order to ensure traceable and quality-assured measurement of modern dielectrics with such low dissipation factors

  • 5.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Influence of coaxial cable on response of high-voltage resisitive dividers2017Conference paper (Refereed)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lightning impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. During these investigations a deterioration of step response was identified when longer coaxial cables were inserted in the measuring circuit. The measured front time T1 was also affected, in one observed case by 2.5 % elongation of front time as another 25 m cable was inserted. Compared to the intention to calibrate front time measurement to better than 5 % uncertainty for front time, this contribution must be well known, or preferably be eliminated. This paper presents the experimental findings from these investigations. The investigated cables included selected coaxial, tri-axial, and cables with a corrugated screen. The effect of cable length was also studied. The influence was first discovered when applying a very fast step (rise-time < 4 ns) to the high voltage arm of a resistive divider and convolution of this step with the time derivative of an ideal lightning impulse with 0.84/60 µs impulse. The calculated output was analysed with IEC 61083 compliant software to evaluate the front time. Subsequently, these analyses have been augmented by additional comparative measurements where two reference dividers were connected to the same impulse generator, and varying the cable length of one of them. The summarized changes in front time calculated for different combinations of cable and impulse voltage dividers are shown and discussed. It is noted that a change in T1 error depends both on length of cable and its type. The results show that non-negligible front time errors may be introduced when the cable length is increased. To support these findings, further tests have been carried out with two reference impulse dividers connected in standard calibration configuration in accordance with IEC 60060-2. One divider was used as reference, while the cable for the other was varied. In this way, the change of error between configurations could be measured. A theoretical study has also been performed, calculating the distortion of a lightning impulse on a coaxial cable. The results agree qualitatively with experiments, but the detailed results show discrepancies that need further investigation.

  • 6.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Bergman, Sixten
    Consultant, Rönnvägen 1 A, 507 71 Gånghester, Sweden.
    Hoffmann, Christian
    Baur Gmbh, 6832 Sulz, Austria.
    Paulus, Eberhard
    Baur Gmbh, 6832 Sulz, Austria.
    Elg, Alf-Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Traceable measurement of dielectric dissipation factor at Very Low Frequency2013Conference paper (Refereed)
    Abstract [en]

    Very Low Frequency (VLF) tests are often used for after-laying tests of power cables since the reactive power demand is much lower at VLF than at 50 Hz. In order to augment the usefulness of the test, it is often complemented by a measurement of dielectric dissipation factor (tan ), where the acceptance of the tested object is based on this measurement. A traceability chain for dissipation factor at high voltage and very low frequency has as yet not been recognized by the International Bureau of Weights and Measures (BIPM), which results in difficulties to prove the quality of the measurement. The measurement is complicated by the limited range of the current in the test object that can be resolved by available high voltage test equipment, thus limiting the possible choices of reference systems. A novel reference measuring system that can fulfil these needs has been developed at SP Technical Research Institute of Sweden in the capacity as National Measurement Institute. The traceability of the system to National Standards of Measurement is ensured by careful scientific work and analyses. This measuring system has the ability to measure dissipation factor at 0.1 Hz in the voltage range from 0.5 kV up to 50 kV with an uncertainty better than 0.004 %.

  • 7.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Elg, Alf-Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Hällström, Jari
    VTT-MIKES, Finland.
    Evaluation of step response of transient recorders for lightning impulse2017Conference paper (Refereed)
    Abstract [en]

    High voltage equipment will be subjected to several types of electrical stress during operation. A battery of factory tests is defined to ensure that the equipment will perform satisfactorily in service. One of the crucial tests is to apply a simulated lighting impulse as standardised to a double-exponential impulse with at front time of 1.2 µs (± 30 %) and a time to half value of 50 µs (± 20 %). Although this wave-shape only approximates natural lightning, there is a solid body of experience within industry, proving that reliability of equipment in service is adequately proven by the standard waveform. It is however crucial for consistency of results that the both voltage level and wave-shape are correctly measured. This paper discusses the requirements and performance of the recording instruments used, leaving the properties of high voltage impulse dividers outside the discussion. The requirements for the recording instrument – transient recorder – are given in IEC 61083-1. The standard provides requirements for, and/or tests to verify, that the recorder has moderately fast response, fast settling time, high resolution, linearity under dynamic conditions, high accuracy and reasonably low internal noise. This is partly in contrast to major trends in transient recorder development, where fast sampling and fast step response are prioritized ahead of high accuracy and fast settling without creeping response. We have therefore evaluated several commercially available recorders in order to find one with respectively flat and reasonably fast step response. In this campaign, a proprietary step generator based on the use of a mercury reed relay has been used. Evaluation of this device is submitted to ISH 2017. It has been found that the measured flatness of the step response directly after the step is a good first indicator of the performance of the transient recorder. This is identified in IEC 61083-1 clauses 1.5.2 and 1.5.3, as a requirement on stability of the recorded step from 0.5 T1min to T2max. For lightning impulse this means from 0.42 µs to 60 µs. For approved transient recorders the requirement is to be within 1 %. For reference transient recorders, a limit of not more than 0.5 % should be applied. Further proof of the accuracy of the transient recorder can be achieved by convolution of an ideal waveform with the recorded step response and analysing the resulting curve with lightning impulse parameter software. A third possibility is to make direct calibration of the transient recorder, using a calculable impulse calibrator. Several state-of-art transient recorders have been evaluated and the results show that only a few are suited for measurement of lightning impulse. Also, the variation of the performance between the ranges and channels of one instruments are significantly large. Both direct assessment of step response as well as result of convolution with a theoretical 0.84/50 µs impulse will be reported. The agreement with results obtained with a calculable impulse calibrator will be illustrated.

  • 8.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Characterisationat low voltage of two reference lightning impulse dividers2017Conference paper (Refereed)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lighting impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. At SP - RISE Research Institutes of Sweden, a 500 kV resistive reference divider has been in use since 2000. Additionally an 800 kV resistive divider is investigated as a possible reference divider for UHV lightning impulse measuring systems. The best uncertainty for the 500 kV reference measuring system is 1 % for voltage amplitude and 3 % for time parameters. The present work aims at lowering these uncertainties by means of better characterisation and evaluation of the possibilities to apply corrections for known errors. The scale factor and dynamic behaviour of a resistive divider can be conveniently determined at low voltage and frequency. Further experiments such as linearity tests and augmented by scientific work is needed to ascertain the performance at high voltage. Step response plays a major role in the characterisation of dividers, and in this work much effort has gone into gathering step responses and evaluating them for various circuit layouts to characterise the variation of the step response due to circuit dimensions and diverse proximity effects. The step applied to the divider is generated by a mercury wetted relay based step generator with an output voltage of 200 V. The step rise-time is a few ns, and thus appreciably faster than the response of the divider. Apart from inspection of the step response itself, evaluation of measurement errors is performed by convolving an ideal curve with the step response of the divider, including its transmission cable. The convolved signal is evaluated with impulse evaluation software and the parameters compared to the ideal input. The difference is a measure of the errors introduced by the divider. This procedure follows IEC 60060-2: 2010.

  • 9.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Elg, Alf-Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Meisner, Johann
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Passon, Stephan
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Hällström, Jari
    VTT-MIKES, Finland.
    Lehtonen, Tapio
    VTT-MIKES, Finland.
    Characterization of a fast step generator2017Conference paper (Refereed)
    Abstract [en]

    Lighting impulse measurements are made as a matter of routine in high voltage testing of high-voltage electrical equipment. The test is often decisive for acceptance of the equipment under test, and consequently proper and precise calibration of the measuring system is needed. The present work centres on the need to quantify the errors of reference measuring systems for lightning impulse. Scale factor determination at low frequency (or DC) is the starting point for this determination. The extrapolation from this frequency domain to the domain where microsecond pulses must be faithfully captured requires application either of methods in the frequency domain or in the time domain. Radio frequency measurements are only well defined for coaxial structures and at impedances in the range of 50 O or thereabouts, making them difficult to apply to the large structures of high-voltage measuring systems. The converse method in the time domain is to apply a Dirac impulse to the system and calculate the response to an assumed input signal by convolution. A true Dirac pulse is not readily available and in practice the applied pulse is a step voltage, which is then derived with respect to time and convolved with the applied signal to obtain the response of the measuring system. The step generator used for this purpose should have very fast front without oscillations. The intent is to achieve a close approximation of an ideal step function, which when derived with respect to time, yields the impulse response of a tested system. A necessary prerequisite is that the step is much steeper than the lightning impulse, and is flat after the step on times much longer than the impulse. The ideal switch element in such a step generator should have infinite resistance and zero capacitance in the off-state, very fast switching to on-state and very low resistance in on-state. The mercury wetted reed switch has often been used for this purpose since it has good characteristics in all these respects. Few, if any, electronic components exhibit competitive advantages compared to the reed switch. The relative lack of parasitic effects means that it is close to being an ideal device. Based on earlier experiences by the authors, a new design has been developed with focus on electrical screening and coaxial design in order to realise a step generator that works into a high impedance instrument. Considerable work has been performed to characterise the new device with regard to steepness of step and most importantly, to voltage stability after the step. The most demanding part of this work has been to separate the performance of the switch from that of the oscilloscope. Findings indicate that the step rise-time is less than 0.5 ns, and settling to within 0.5 % within 10 ns.

  • 10.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Comparison between GaAs and graphene QHR standards for resistance realisation at SP2016Conference paper (Refereed)
    Abstract [en]

    We report the first precision QHR measurements at SP using a graphene chip. We compare the results of a resistance calibration using GaAs based chips with the results using a graphene chip. The results agree within a few parts in 109 for calibrations of 100 Ω and 10 kΩ resistors. Consistency checks indicate that the uncertainty is lower with the graphene chip, and the noise level is slightly lower. The measurements with the graphene chip were performed exclusively at 4.2 K, which simplifies the calibration procedure considerably compared with GaAs chips.

  • 11.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Eklund, Gunnar
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    He, Hans
    Chalmers tekniska högskola, Gothenburg, Sweden.
    Comparing GaAs and graphene QHR standards for resistance realisation at SP2016Conference paper (Other academic)
  • 12.
    Bergsten, Tobias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Rydler, Karl-Erik
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Realisation of Absolute Phase and Ac Resistance of Current Shunts by Ratio Measurements2018In: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Conference paper (Refereed)
    Abstract [en]

    This article presents a method for realising absolute phase and ac resistance for current shunts using only impedance ratio measurements. The method is based on three geometrically identical current shunts with different resistances, but with the same inductance, capacitance and ac resistance (change of resistance at ac compared to dc), We demonstrate how the inductance, capacitance and ac resistance can be calculated from the complex impedance ratio measurements, thereby realising absolute current shunt impedance. This method simplifies the procedure of current shunt calibration, since the same impedance ratio setup which is used to compare a shunt to a reference shunt, is used to realise the impedance of the starting reference shunt.

  • 13.
    Bergstrand, Sten
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Activities of the IERS Working Group on Site Survey and Co-location2016In: IVS 2016 General Meeting Proceedings: "New Horizons with VGOS" / [ed] Dirk Behrend, Karen D. Baver, and Kyla L. Armstrong, Greenbelt, MD: National Aeronautics and Space Administration , 2016, p. 113-117Conference paper (Other academic)
    Abstract [en]

    t The objective of the International Earth Rotation and Reference Systems Service (IERS) Working Group on Site Survey and Co-location is to improve local measurements at space geodesy sites. We appointed dedicated Points of Contact (POC) with the four different services of IERS as well as the NASA Space Geodesy Project in order to improve the efficiency of internal communication within the working group. Following the REFAG2014 conference, the POCs agreed on a common and general terminology on local ties that clarifies the communication regarding site surveying and co-location issues between and within the IERS services. We give brief introductions to the different observation techniques and mention some contemporary issues related to site surveying and co-location.

  • 14.
    Bergstrand, Sten
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Herbertsson, Magnus
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Spetz, Jörgen
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Svantesson, Claes-Göran
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Haas, Rüdiger
    Chalmers University of Technology, Sweden.
    A gravitational telescope deformation model for geodetic VLBI2018In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394Article in journal (Refereed)
    Abstract [en]

    We have measured the geometric deformations of the Onsala 20 m VLBI telescope utilizing a combination of laser scanner, laser tracker, and electronic distance meters. The data put geometric constraints on the electromagnetic raypath variations inside the telescope. The results show that the propagated distance of the electromagnetic signal inside the telescope differs from the telescope’s focal length variation, and that the deformations alias as a vertical or tropospheric component. We find that for geodetic purposes, structural deformations of the telescope are more important than optic properties, and that for geodetic modelling the variations in raypath centroid rather than focal length should be used. All variations that have been identified as significant in previous studies can be quantified. We derived coefficients to model the gravitational deformation effect on the path length and provide uncertainty intervals for this model. The path length variation due to gravitational deformation of the Onsala 20 m telescope is in the range of 7–11 mm, comparing elevation 0$$^{\circ }$$∘and 90$$^{\circ }$$∘, and can be modelled with an uncertainty of 0.3 mm.

  • 15.
    Boork, Magdalena
    et al.
    RISE - Research Institutes of Sweden, Built Environment.
    Wendin, Karin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Nordén, Johan
    RISE - Research Institutes of Sweden.
    Nilsson Tengelin, Maria
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Innemiljö i nytt ljus: Metoder för objektiv bedömning av belysning2017Report (Other academic)
    Abstract [sv]

    Nuvarande belysningsstandarder baseras enbart på tekniska krav, såsom ljusstyrka, jämnhet och luminans. Att även inkludera upplevelsebaserade krav skulle troligen främja bättre ljuskomfort, men även mer energieffektiva ljusmiljöer och produkter. Kunskapen om hur upplevda belysningsparametrar kan beskrivas är dock begränsad. Detta hämmar fastighetsägare och brukare att precisera önskvärda ljusmiljöer, liksom belysningstillverkare att utveckla produkter för nya marknader och tillämpningar. Syftet med detta forskningsprojekt var att utveckla och tillämpa sensoriska metoder på belysning. Till skillnad från tidigare metoder möjliggör sensoriska metoder objektiva bedömningar av upplevda belysningsparametrar.

    En analytisk panel bestående av åtta personer som uppfyller särskilda urvalskriterier rekryterades och tränades att bedöma belysningsprodukter i ett multisensoriskt laboratorium på SP Sveriges Tekniska Forskningsinstitut i Borås. Metodutvecklingen fokuserade särskilt på en effektiv träningsprocedur, hantering av ögats adaption, samt bedömning av färg och skuggningar. Förutom laboratorie-försök undersöktes möjligheten att genomföra analytiska bedömningar i en verklig kontext med samma försöksuppställning och panel.

    Resultaten visar att det är möjligt att använda sensorisk metodik för att genomföra objektiva belysningsbedömningar av armaturer; paneldeltagarna kunde skilja mellan attribut och prover. Signifikanta skillnader identifierades mellan de olika armaturerna, både i form av sensoriska och fysikaliska egenskaper såsom läsbarhet och bländning. Fysikaliska och sensoriska parametrar samvarierar dock inte alltid, vilket visar att fysikaliska och sensoriska mätningar ger kompletterande information om belysningskvalitet. Vidare visade bedömningsförsök i en verklig kontext att samma resultat uppnåddes som i laboratoriet, men med lägre signifikans, vilket verifierar metodens tillämpbarhet på belysning.

    Den genererade kunskapen väntas på sikt bidra till utveckling av verktyg som stödjer kommunikationen mellan olika professioner inom ljusdesign och planering och på så vis främja mer önskvärda och energieffektiva ljusmiljöer.

  • 16.
    Brolin, Magnus
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Aggregator trading and demand dispatch under price and load uncertainty2016In: IEEE PES Innovative Smart Grid Technologies Conference Europe, 2016Conference paper (Refereed)
    Abstract [en]

    The liberalization of electricity markets and the transformation of electric power systems to include large amounts of variable output generation, has led to a growing interest in flexible demand and demand response. Making demand response available on the wholesale market on a large scale is a challenge. Retailers and aggregators, providing services to individual consumers as well as bringing aggregated flexibility to the wholesale market, is foreseen to play important roles in this respect. This paper presents a aggregator decision support model for demand scheduling, including demand response and purchase bid optimization for day-ahead markets. Income from providing electricity to consumers, and costs related to imbalances, rescheduling and energy not served are also considered. The model includes risk management by applying the conditional value-at-risk risk measure. The feasibility of the developed model is validated through a case study using historical data from the Swedish power system and market.

  • 17.
    Cano, Stefan J
    et al.
    Modus Outcomes, UK.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Barbic, Skye P
    University of British Columbia, Canada.
    Fisher Jr, William P
    University of California, US.
    Patient-centred outcome metrology for healthcare decision-making2017Conference paper (Refereed)
    Abstract [en]

    Valid and precise quantification of clinical variables is essential for appropriate interpretation to inform healthcare decision making. The outcomes produced from different measurement procedures and instruments, purporting to quantify the same measurand, should be directly comparable. This ensures the appropriate application and widespread adoption of clinical research findings. Metrology provides a framework for the development of a common language of reference measurement systems, which have the potential to improve the accuracy and comparability of patients’ results. However, the practices, procedures and instruments used in social measurement are currently excluded from any formal metrological framework. In this paper, we build on previous arguments, and propose a new international body to bring together metrology, psychometrics, philosophy, and clinical management to support the global comparability and equivalence of measurement results in patient centred outcome measurement to improve healthcare.

  • 18.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Qualifying a Transient Recorder for Traceable Measurements of Very Fast Transients2018In: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Conference paper (Refereed)
    Abstract [en]

    This paper presents the qualification of a transient recorder used in a system for traceable measurements of Very Fast Transients. The system is designed for traceable measurements of VFT up to 100 kV, having a target settling time < 10 ns, a peak voltage error < 1\%, and a front time error < 5\%. The rise time of the digitizer is 1.6 ns at 50Ω and 1.2 ns at 1 MΩ. Step responses show settling times of 4.5 ns. A convolution method gives a peak voltage error of 0.12% and a front time error of 4.1% for 4.5ns front times. © 2018 IEEE.

  • 19.
    Flys, Olena
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology. Halmstad University, Sweden.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Petronis, Sarunas
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Stenlund, Patrik
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Rosen, B. -G
    Halmstad University, Sweden.
    Applicability of characterization techniques on fine scale surfaces2018In: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, no 3, article id 034015Article in journal (Refereed)
    Abstract [en]

    In this study, several surface topographies typical for dental implants were evaluated by different measurement techniques. The samples were prepared by machine turning, wet chemical etching and electrochemical polishing of titanium discs. The measurement techniques included an atomic force microscope (AFM), coherence scanning interferometer (CSI) and a 3D stereo scanning electron microscope (SEM). The aim was to demonstrate and discuss similarities and differences in the results provided by these techniques when analyzing submicron surface topographies. The estimated surface roughness parameters were not directly comparable since the techniques had different surface spatial wavelength band limits. However, the comparison was made possible by applying a 2D power spectral density (PSD) function. Furthermore, to simplify the comparison, all measurements were characterized using the ISO 25178 standard parameters. Additionally, a Fourier transform was applied to calculate the instrument transfer function in order to investigate the behavior of CSI at different wavelength ranges. The study showed that 3D stereo SEM results agreed well with AFM measurements for the studied surfaces. Analyzed surface parameter values were in general higher when measured by CSI in comparison to both AFM and 3D stereo SEM results. In addition, the PSD analysis showed a higher power spectrum density in the lower frequency range 10-2-10-1 μm-1 for the CSI compared with the other techniques.

  • 20.
    Havunen, Jussi
    et al.
    VTT-MIKES, Finland.
    Hällström, Jari
    VTT-MIKES, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Bergman, Allan E.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Using deconvolution for correction of non-ideal step response of lightning impulsedigitizers and measurement systems2017Conference paper (Refereed)
    Abstract [en]

    Lightning impulse measurements can be highly influenced by measurement arrangement, characteristics of high voltage divider, digitizer (transient recorder) performance, and algorithms used for parameter evaluation. The main sources of measurement errors are the non-ideal step responses of digitizer and voltage divider. This paper discusses the use of deconvolution to correct for the non-ideal step response of a digitizer, and of a large mixed divider. Correcting the step response of the complete measuring system by one part at a time is desirable because it allows to evaluate the effectiveness of the correction with trustworthy methods. Step response describes the output of a system as function of time when its input changes between two levels infinitely fast. Real life impulse digitizers and impulse voltage dividers have a finite rise time, and the response does not immediately settle to final value. Slow rise time is often the cause of error for front time parameter. Creeping response is often the cause of error for time to half-value parameter. Step response of an instrument can be determined by applying a stable, known direct voltage, which is then shorted to ground by a mercury-wetted relay. The mercury-wetted relay is assumed nearly an ideal switch, which creates almost an ideal voltage step for input of the instrument. Convolving the derivative of the measured step response with an ideal input gives a measure of distortion caused by the non-perfect step response, and conversely deconvolving the measured step response with the measured signal gives the original input signal. This paper presents an FFT-based method for step response correction using deconvolution. Deconvolution is a mathematical process, which is used to reverse the non-ideal effects of measuring instrument on recorded data. Effectiveness of the method is demonstrated by two examples. In the first example, the non-ideal step responses of the different ranges of an impulse digitizer are corrected. Functionality of the step response correction is evaluated by comparing the results against a calculable impulse voltage calibrator. Results showed that the step response correction reduced errors in lightning impulse parameters. Stability of the step response correction was analysed by studying several impulse calibration results that have been performed for the instrument within a year. The second example corrects the response of a 2400 kV impulse voltage divider. The effectiveness of the correction is evaluated by comparing its results to a 400 kV reference divider.

  • 21.
    Hedekvist, Per Olof
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Weddig, Ludwig
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Ebenhag, Sven C
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Analysis and compensation of polarization in an optical frequency transfer through a fiber communication network2018Conference paper (Refereed)
    Abstract [en]

    In the fiber optic link, connecting RISE research facilities in Borås with the Photonics Lab at Chalmers University of Technology in Gothenburg, the signal is substantially distorted by polarization variations. It has been verified that the variations are induced by the electrical power grid, however unknown at which segment of the link that it occurs. While this distortion is effectively handled by standard equipment for the data transmission, it deteriorates the detection of a transmitted ultra-stable frequency, using heterodyne mixing. Thus, the magnitude and severity of this distortion is quantified, and some compensation techniques are evaluated.

  • 22.
    Hiller, Carolina
    et al.
    RISE - Research Institutes of Sweden, Built Environment.
    Wendin, Karin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Nilsson Tengelin, Maria
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Utveckling och tillämpning av sensoriska metoder för objektiva belysnings-bedömningar, del I2017Report (Other academic)
    Abstract [sv]

    I dag finns tekniska belysningsstandarder som inkluderar parameterar så som ljusstyrka, jämnhet och luminans. Det som saknas är krav som grundar sig på människors upplevelser av belysning och ljusmiljöer. Att få med den upplevelsebaserade dimensionen skulle betyda ett helhetstänk som förmodligen skulle gynna både ljuskomforten och än mer energieffektiva ljusmiljöer och produkter. Att beskriva upplevda belysningsparametrar har hittills visat sig inte vara helt enkelt, och här saknas både kunskap och en gemensam begreppsvärld inom branschen; något som hämmar fastighetsägare att ställa lämpliga krav vid en upphandling liksom belysningstillverkare att utveckla produkter för nya marknader och tillämpningar. Det övergripande syftet med detta forskningsprojekt är att utveckla och tillämpa sensoriska metoder på belysning. Till skillnad från tidigare metoder möjliggör sensoriska metoder objektiva bedömningar av upplevda belysningsparametrar. Syftet med försöken som redovisas i denna delrapport är att vidareutveckla och testa metoden ytterligare. Detta görs genom att nya armaturer testas liksom att försök utförs i en ny verklig kontext (kontorsmiljö). Försöken bygger vidare på resultat från tidigare försök som har rapporterats om i (Boork et al, 2017).

    En analytisk panel bestående av åtta personer, som uppfyllde särskilda urvalskriterier, har tidigare rekryterats och dessa personer tränades nu för detta specifika delprojekt för att bedöma belysningsprodukter i ett multisensoriskt laboratorium på RISE Research Institutes of Sweden i Borås. Metodutvecklingen fokuserade särskilt på en effektiv träningsprocedur, hantering av ögats adaption, samt bedömning av färg och skuggningar. Förutom laboratorieförsök undersöktes möjligheten att genomföra analytiska bedömningar i en verklig kontext med samma försöksuppställning och panel.

    Resultaten visade att det är möjligt att använda sensorisk metodik för att genomföra objektiva belysningsbedömningar även för de testade belysningsprodukterna, dvs mindre LED-spotlights. Signifikanta skillnader identifierades mellan de olika armaturerna och som i tidigare försök spelade färgtemperaturen en stor roll för flera av de bedömda egenskaperna; inte minst förstås för ljuskällans gulhet och för läsbarhet (textkontrasten). Liksom i tidigare försök fanns det samband mellan de fysikaliska mätningarna och sensoriska bedömningarna, men inte för alla egenskaper, vilket visar att fysikaliska och sensoriska mätningar ger kompletterande information om belysning.  Vidare visade bedömningsförsök i en verklig kontext att likvärdiga resultat uppnåddes som i laboratoriet, om ändock något spretigare och inte heller lika entydiga i jämförelse med verklig kontext i tidigare försök.

    Den genererade kunskapen väntas på sikt bidra till utveckling av verktyg som stödjer kommunikationen mellan olika professioner inom ljusdesign och planering och på så vis främja mer önskvärda och energieffektiva ljusmiljöer.

  • 23.
    Hällström, J
    et al.
    Helsinki University of Technology (TKK), Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Ding,
    Beijing Hua Tian Mechanical-Electrical Institute (BHT), China.
    Garnacho, F
    Electrotechnical Official Central Laboratory (LCOE), Spain.
    Gobbo, R
    University of Padova, Italy.
    Kato, T
    Doshisha University, Japan.
    Li, Y
    National Measurement Institute (NMIA), Australia.
    Nilsson, Andreas
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Pesavento, G
    University of Padova, Italy.
    Sato, S
    Utsunomiya University, Japan.
    Yu, AX
    Beijing Hua Tian Mechanical-Electrical Institute, China.
    International comparison of software for calculation of lightning impulse parameters based on a new processing algorithm2007Conference paper (Refereed)
    Abstract [en]

    A new algorithm has been proposed to calculate the parameters of full lightning voltage impulses. The new algorithm enables the application of the test voltage factor (also referred to as k-factor in some literatures) for calculation of the equivalent test voltage of impulses with superimposed oscillations/overshoots. The new algorithm at the same time provides a robust procedure for obtaining time parameters of the impulses from not only smooth waveforms but also waveforms with varying degrees of distortions in the front part of the impulses. These distortions include oscillations on the impulse front and overshoots in the peak region. A critical part of the new algorithm is a 4-parameter fitting procedure to obtain the base curve, which is used for calculation of the test voltage curve. Another important part of the algorithm is applying a filtering procedure in the calculation of the test voltage curve.

     

    The new algorithm was tested in different laboratories using different programming languages and different techniques for realising the fitting and filtering routines. The paper reports the results obtained from the participating laboratories using the proposed algorithm. The results obtained by the participating laboratories using existing software based on the requirement of IEC 60060-1: 1989 were also compared. It is anticipated that the results can serve as a part of the basis for a new procedure for determination of lightning impulse parameters in the revised IEC 60060-1.

  • 24.
    Iacomussi, P
    et al.
    INRIM, Italy.
    Rossi, G
    INRIM, Italy.
    Blatter, P
    METAS, Switzerland.
    Reber, J
    METAS, Switzerland.
    Chain, C
    Cerema, France.
    Muzet, V
    Cerema, France.
    Dubard, J
    LNE, France.
    Van Tang, C
    LNE, France.
    Jouanin, A
    OPTIS, France.
    Kubarsepp, T
    Metrosert, Estonia.
    Lindgren, Mikael
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Manocheri, F
    AALTO, Finland.
    Zehntner, P
    Zehntner GmbH, Switzerland.
    Metrology of Road Surface for Smart Lighting2017In: PROCEEDINGSOF THE LUX EUROPA 2017 European Lighting Conference: Lighting for modern society / [ed] Matej B. Kobav, University of Ljubljana, Slovenia, Ljubljana, 2017, p. 103-107, article id OM17Conference paper (Refereed)
    Abstract [en]

    The knowledge of the luminance coefficient q or of the reduced luminance coefficient r of road surface is an unavoidable requirement for designing road lighting installations able to assure adequate road luminance for visual conditions, energy consumption and traffic safety according to standard requirements. Unfortunately q available data refers to measurements made during the seventies with no traceability or measurement uncertainty. In the last 40 years the road surfaces pavements evolved as well the road lighting sources and luminaires. EMPIR project SURFACE will provide validated, optimised and reliable geometrical conditions for the measurement of q as well as reference data representative of current road pavements and future needs, as support of the European Standardisation process, CIE and European Metrology infrastructure.

  • 25.
    Jaldehag, Kenneth
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Jarlemark, Per
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Evaluation of CGGTTS time transfer software using multiple GNSS constellations2018Conference paper (Refereed)
    Abstract [en]

    A new software tool for GNSS time transfer implementing the Common GNSS Generic Time Transfer Standard (CGGTTS) has been developed by the time and frequency group at RISE Research Institutes of Sweden. The software handles signals from the satellite navigation systems GPS, GLONASS, Galileo and BeiDou including the most important ranging codes for time transfer applications. The aim of the development is to provide an alternative to existing software and to support time transfer with new GNSS. The paper presents an evaluation of CGGTTS data calculated with the new software tool in comparison with those calculated using two other, independently developed software tools. It is shown that the results obtained from the different software agree to the sub-nanosecond level. Specifically, the agreement seen between individual GPS, Galileo and BeiDou CGGTTS data is at the 100- to 200-picosecond level. Similarly, GLONASS CGGTTS data agree to the sub-nanosecond level. Further, the paper presents a comparison between time transfer links for both long baselines and short, common-clock baselines obtained from a common view analysis of CGGTTS data from the four mentioned GNSS, as well as a combination of them. It finally discusses other features available from the RISE software, such as non-smoothed CGGTTS data, adoption of satellite orbit and clock products from the IGS as well as the results of an evaluation using linear combinations with non-standard CGGTTS codes and signals.

  • 26.
    Jiang, Zhiheng
    et al.
    BIPM Bureau International des Poids et Mesures, France.
    Zhang, Victor
    NIST National Institute of Standards and Technology, US .
    Huang, Yi-Jiun
    Telecommunication Laboratories, Chinese Taipei.
    Achkar, Joseph
    Sorbonne Université, France.
    Piester, Dirk
    PTB, Germany.
    Lin, Shinn-Yan
    Telecommunication Laboratories, Chinese Taipei.
    Wu, Wenjun
    National Time Service Center, China.
    Naumov, Andrey
    Main Metrological Center for State Service of Time and Frequency, Russia.
    Yang, Sung-hoon
    Korea Research Institute of Standards and Science, Korea.
    Nawrocki, Jerzy
    Space Research Center Astrogeodynamic Observatory, Poland.
    Sesia, Ilaria
    Istituto Nazionale di Ricerca Metrologica, Italy.
    Schlunegger, Christian
    Federal Institute of Metrology METAS, Switzerland.
    Yang, Zhiqiang
    National institute of Metrology, China.
    Fujieda, Miho
    NICT National Institute of Information and Communications Technology, Poland.
    Czubla, Albin
    PL/GUM Central Office of Measures, Poland.
    Esteban, Hector
    ROA Real Instituto y Observatorio de la Armada, Spain.
    Rieck, Carsten
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Whibberley, Peter
    NPL National Physical Laboratory, UK.
    Use of software-defined radio receiversin two-way satellite time and frequencytransfers for UTC computation2018In: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, p. 685-698Article in journal (Refereed)
    Abstract [en]

    Two-way satellite time and frequency transfer (TWSTFT) is a primary technique for thegeneration of coordinated universal time (UTC). About 20 timing laboratories around theworld continuously operate TWSTFT using satellite time and ranging equipment (SATRE19)modems for remote time and frequency comparisons in this context. The precision of theSATRE TWSTFT as observed today is limited by an apparent daily variation pattern (diurnal)in the TWSTFT results. The observed peak-to-peak variation have been found as high as 2 nsin some cases. Investigations into the origins of the diurnals have so far provided no completeunderstanding about the cause of the diurnals. One major contributor to the diurnals, however,could be related to properties of the receive part in the modem. In 2014 and 2015, it wasdemonstrated that bypassing the receive part and the use of software-defined radio (SDR) receivers in TWSTFT ground stations (SDR TWSTFT) instead could considerably reduce boththe diurnals and the measurement noise.In 2016, the International Bureau of Weights and Measures (BIPM) and the ConsultativeCommittee for Time and Frequency (CCTF) working group (WG) on TWSTFT launched a pilotstudy on the application of SDR receivers in the TWSTFT network for UTC computation.The first results of the pilot study were reported to the CCTF WG on TWSTFT annualmeeting in May 2017, demonstrating that SDR TWSTFT shows superior performancecompared to that of SATRE TWSTFT for practically all links between participating stations.In particular, for continental TWSTFT links, in which the strongest diurnals appear, the useof SDR TWSTFT results in a significant suppression of the diurnals by a factor of betweentwo and three. For the very long inter-continental links, e.g. the Europe-to-USA links wherethe diurnals are less pronounced, SDR TWSTFT achieved a smaller but still significant gainof 30%. These findings are supported by an evaluation of some of the links with an alternatetechnique based on GPS signals (GPS IPPP) as reported in this paper.Stimulated by these results, the WG on TWSTFT prepared a recommendation for the 21stCCTF meeting, which proposed the introduction of SDR TWSTFT in UTC generation. WithCCTF approval of the recommendation, a roadmap was developed for the implementationof SDR TWSTFT in UTC generation. In accordance with the roadmap, most of the stationsthat participated in the pilot study have updated the SDR TWSTFT settings to facilitatethe use of SDR TWSTFT data in UTC generation. In addition, the BIPM conducted a finalevaluation to validate the long-term stability of SDR TWSTFT links, made test runs using theBIPM standard software for the calculation of UTC, now including SDR TWSTFT data, andstarted to calculate SDR TWSTFT time links as backup from October 2017. The use of SDRTWSTFT in UTC generation will begin in 2018.

  • 27.
    Järn, Mikael
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Grund Bäck, Lina
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Andersson, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Karlsson, Stefan
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Mesoporous sol-gel based SiO2 thin films with ordered pore orientation as antireflective coatings on glass2017Conference paper (Refereed)
    Abstract [en]

    Antireflective coatings on glass have increasing applications, on e.g. cover glass of PV modules, display glass, spectacle lenses or window glazing’s. Sol-gel derived mesoporous coatings can be tuned both in terms of porosity and thickness, thus allowing tuning of the refractive index. Additionally, the sol-gel approach is bottom-up, which facilitates easy upscaling. In the current work we present dip-coated mesoporous silica coatings of different pore orientation and film thickness prepared on microscope glass slides and silicon wafers. The silica coatings were derived from TEOS (tetraorthosilicates) mixed with ethanol and diluted HCl. Hexagonal and cubic pore ordering of the thin films with a pore size in the range of 5-10 nm were obtained. The thin films were characterized in terms of non-contact profilometry, stylus profilometry,  nanohardness, scratch resistance, UV-Vis-NIR transmittance and UV-Vis-NIR reflectance. The thicknesses of the studied films varied from 100 nm up to several hundreds of nm without jeopardizing the film homogeneity. All the mesoporous films exhibited higher transmittance than the uncoated glass substrate. The film with hexagonal pore orientation has a somewhat higher nanohardness than the cubic one, however,  no difference was found in the scratch resistance for the films with different pore orientations.

  • 28.
    Kanerva Rice, Sophie
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Petersson, Niclas
    RISE - Research Institutes of Sweden.
    Nordlinder, Jesper
    SCA Hygiene Products AB, sWEDEN.
    Farbrot, Anne
    SCA Hygiene Products AB, Sweden.
    Rationale and Design of a Novel Method to Assess the Usability of Body-Worn Absorbent Incontinence Care Products by Caregivers.2018In: Journal of Wound, Ostomy and Continence Nursing (WOCN), ISSN 1071-5754, E-ISSN 1528-3976, Vol. 45, no 5, p. 456-464Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The purpose of this study was to develop and test a new method to measure the usability of absorbent incontinence care products from the caregivers' perspective and to investigate if the method can be used to differentiate between product types in a product change.

    DESIGN: Process evaluation and validation study.

    SUBJECTS AND SETTING: Product developers and end users participated in designing the new method. Thereafter, professional caregivers acted as testers of the new method, ranking usability when performing absorbent product changes on patients in a simulated nursing home care environment, assisted by third-party research institute moderators.

    METHODS: Design and evaluation of a new method designed to assess the usability of body-worn absorbent incontinence care products for lay caregivers were completed. The evaluation included formative and summative evaluations of effectiveness (product fit), efficiency (time and physical workload), and satisfaction. A person-centered approach aimed at including all subjects and settings to generate a single usability score for decision making and product benchmarking. Experienced caregivers changed 4 types of products: (1) disposable body-worn pads with mesh briefs (2-piece system); (2) disposable all-in-one briefs; (3) disposable, T-shaped, and belted brief; and (4) disposable pull-up pants on simulated patients in standing or lying position. Each product change was performed by 1 unassisted experienced caregiver. The probability of success as a score for each product type was calculated across the 4 metrics and reported with 95% confidence intervals (CIs). Descriptive and inferential statistics were developed assuming a binary statistical model, using the weighted scores from each of the factors. An overall usability score was calculated.

    RESULTS: The method we developed discriminated between usability of different product types. The overall score for the disposable pull-up product (90%; CI: 83%-97%) was better (P < .05) than for the disposable T-shaped brief (83%; CI: 77%-89%), the disposable brief (53%; CI: 45%-61%), and the disposable body-worn pad with mesh pant (61%; CI: 56%-66%) in standing patients. For lying patients, the overall score for the disposable T-shaped brief product (81%; CI: 73%-89% was better (P < .05) than the disposable brief (65%; CI: 45%-61%) and the disposable body-worn pads with mesh brief (62%; CI: 55%-69%). Reliability was evaluated quantitatively in terms of measurement uncertainties in the results.

    CONCLUSION: The method we described demonstrated differentiation of usability based on product type indicating concurrent validity. Further testing in diverse real-world care environments is needed to evaluate and confirm the validity and to assess reliability of this method in the research setting.

  • 29.
    Karlsson, Stefan
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Grund Bäck, Lina
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Andersson, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Sundberg, Peter
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Lundstedt, Karin
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Sehati, Parisa
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Stålhandske, Christina
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Lätta Innovativa Material för Effektiva Solcellsmoduler (LIMES)2017Report (Other academic)
    Abstract [en]

    Extraction of solar energy through solar cells is a promising technology for increasing the share of renewable energy sources, both now and in the future. Glass for solar cells is a significant part of the cost, and a necessity to develop to increase life expectancy and reduce the cost per watt recovered. In the LIMES project have adding optically active components been studied, these absorb harmful UV light and simultaneously converts those UV photons into visible light, which in turn can be converted into energy in solar cells. Thus, the profit is twofold, increasing both the lifetime and efficiency by up to 4%. Further, it has been studied how to optimize the mechanical and chemical properties of glass by optimizing the glass composition in order to increase the mechanical and chemical lifetime. It has shown that resistance to cracking of the new composition increases by a factor of 3 and that the chemical resistance is increased by a factor of 4. Novel thermo-chemical strengthening of glass has been demonstrated in the lab and giving rise to at least equal strengthening level and increases the crack resistance by a factor of 2. It enables the use of thinner glass and thus significantly lighter photovoltaic modules. In the thermo-chemical strengthening process, the glass surface composition is modified significantly by increasing the content of aluminum oxide and thus gives rise to improved properties. The thermo-chemical treatment increases the glass surface contact angle of water, which contributes to a self-cleaning glass. Multifunctional glass surfaces that are both anti-reflective and self-cleaning have been studied by two different approaches, nanostructured surface modification and porous antireflective coatings with photocatalytic degradation ability. Nanostructured glass surfaces gives rise to an increased light scattering and can thus effectively guide diffused light to the solar cells and simultaneously change the glass contact angle with water. The LIMES-concept has been demonstrated by quantitative measurements and manufacturing of small silicon photovoltaic modules. The project has significantly increased the potential for commercialization by increasing the TRL (Technology Readiness Level) level from 2-4 to 4-6. Investigations on how to scale up manufacturing flat glass in order to take the next step towards commercialization is on-going.

  • 30.
    Karlsson, Stefan
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Järn, Mikael
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Welinder, Jan
    RISE - Research Institutes of Sweden, Safety and Transport, Electronics.
    Andersson, Anne
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Liinanki, Matilda
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Försth, Michael
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Transparent intelligens för en bättre värld - en sammanfattning av fyra år med TIME2017In: GLAS, no 2, p. 58-59Article in journal (Other (popular science, discussion, etc.))
  • 31.
    Krishna, Amogh
    et al.
    Halmstad University, Sweden.
    Flys, Olena
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology. Halmstad University, Sweden.
    Reddy, Vijeth
    Halmstad University, Sweden.
    Leicht, Alexander
    Chalmers University of Technology, Sweden .
    Hammar, Lars
    Chalmers University of Technology, Sweden .
    Rosen, BG
    Halmstad University, Sweden.
    Potential approach towards effective topography characterization of 316L stainless steel components produced by selective laser melting process2018In: European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 18th International Conference and Exhibition, EUSPEN 2018, 2018, p. 259-260Conference paper (Refereed)
    Abstract [en]

    In this paper, an attempt is made to explain the surface texture of Selective Laser Melting (SLM) parts more satisfyingly than the existing methods. Investigations were carried out on the 316L stainless steel SLM samples. To account for most of the surface conditions, a truncheon artefact was employed for the analysis. A Stylus Profilometer was employed as a metrology tool for obtaining the 3D surface measurements. A methodology is proposed to extract and characterize the topographic features of Additive Manufactured (AM) surfaces. Here, the overall roughness of the surface is segregated into the roughness of the powder particles and the waviness due to thermal and the "staircase" effects. Analyzing these features individually results in an increased understanding of the AM process and an opportunity to optimize machine settings.

  • 32.
    Krishna, Amogh
    et al.
    Halmstad University, Sweden.
    Flys, Olena
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology. Halmstad University, Sweden.
    Reddy, Vjeth
    Halmstad University, Sweden.
    Rosén, BG
    Halmstad University, Sweden.
    Surface topography characterization using 3D stereoscopic reconstruction of SEM images2018In: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, no 2, article id 024006Article in journal (Refereed)
    Abstract [en]

    A major drawback of the optical microscope is its limitation to resolve finer details. Many microscopes have been developed to overcome the limitations set by the diffraction of visible light. The scanning electron microscope (SEM) is one such alternative: it uses electrons for imaging, which have much smaller wavelength than photons. As a result high magnification with superior image resolution can be achieved. However, SEM generates 2D images which provide limited data for surface measurements and analysis. Often many research areas require the knowledge of 3D structures as they contribute to a comprehensive understanding of microstructure by allowing effective measurements and qualitative visualization of the samples under study. For this reason, stereo photogrammetry technique is employed to convert SEM images into 3D measurable data. This paper aims to utilize a stereoscopic reconstruction technique as a reliable method for characterization of surface topography. Reconstructed results from SEM images are compared with coherence scanning interferometer (CSI) results obtained by measuring a roughness reference standard sample. This paper presents a method to select the most robust/consistent surface texture parameters that are insensitive to the uncertainties involved in the reconstruction technique itself. Results from the two-stereoscopic reconstruction algorithms are also documented in this paper.

  • 33.
    Larzelere, W
    et al.
    Evergreen HV, USA.
    Hällström, J
    VTT, Finland.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Kluss, J
    Mississippi State University, USA.
    Li, Y
    National Measurement Institute, Australia.
    Zhou, L
    Hua Gao, China.
    MEASUREMENT OF THE INTERNAL INDUCTANCE OF IMPULSEVOLTAGE GENERATORS AND THE LIMITS OF LI FRONT TIMES2017Conference paper (Refereed)
    Abstract [en]

    The recent push to higher testing voltages for research and production tests onUHV system components rated above 800kV class has led to difficulties in achieving thestandard waveshapes as required by IEC60060 Parts 1 and 2 and other existing IEC,IEEE/ANSI and other standards. One of the limiting components in achieving themaximum capacitive loading on an impulse generator for standard lightning impulse fronttimes is the inductance of the circuit. The total inductance of the circuit is comprised ofthe internal inductance of the impulse generator and the inductance of the loop toconnect to the load. The higher the voltage class of test objects, the larger the loop,yielding more inductance that in turn, reduces the test capacitance that can be connectedand still remain inside the overshoot requirements of the standards. The internalinductance of the impulse generator is comprised of the wiring of the stages and thestage capacitor inductance and/or the inductance of the waveshaping resistors. Thispaper shows the results of methods to measure and calculate the internal inductance ofseveral impulse generators and we review the formulas for calculating the maximum loadof an impulse generator with a given internal inductance. We believe these methods givemore realistic values than adding up nameplate inductance values from an impulsegenerator. The paper also reviews the pros and cons of higher stage capacitances inimpulse generators to test larger loads that are ultimately limited by the circuit inductancevalue. The intent of this paper is to assist in the revision of future IEC and IEEE standardsfor impulse testing apparatus in the UHV range

  • 34.
    Lindgren, Mikael
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Nord, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Characterization of visual and IR reflectivity for soft car targets2018Conference paper (Other academic)
    Abstract [en]

    Advanced Driver Assistance Systems (ADAS) and Automated Driving (AD) vehicles rely heavily on optical sensors. Extensive testing of optical sensors is required and typically performed at test tracks like AstaZero. Soft surrogate targets are used for safety reasons, but the optical characteristics of surrogate targets may differ considerably from that of real vehicles. During tests the quality of the soft surrogate targets deteriorates due to repeated impacts and reassembly of the targets, and there is a need for methods to secure the quality of the soft surrogate targets over time.

    RISE has conducted a project together with Volvo Cars and Veoneer to develop and validate accurate and repeatable measurement methods of the optical characteristics of 3D soft car targets. The goal is to support international standardisation (ISO) with standard methods enabling future verification and calibration of optical characteristics of active safety 3D soft car targets.

    The poster presents results from optical measurements on soft car targets and real cars, performed in the project. One target was subjected to 100 rear-end collisions during which the reflectivity was measured.

  • 35.
    Lu, Xiauhu
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Soenen, Hilde
    Nynas NV, Belgium.
    Structural and chemical analysis of bitumen using time-of-flight secondary ion mass spectrometry (TOF-SIMS)2017In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 199, p. 206-218Article in journal (Refereed)
    Abstract [en]

    The chemical composition and structures of bitumen surfaces are characterised using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The effect of wax is considered by comparing a wax-free bitumen with a bitumen that contains natural wax and a wax-free bitumen to which a small amount of wax has been added. The results demonstrate that TOF-SIMS is a powerful method for the chemical characterisation of surface structures and phase segregation phenomena in bitumen. It is evident that the structures formed on the bitumen surface are closely related to the wax content and that these structures, as well as the surface in general, are enriched in wax-related compounds (aliphatic hydrocarbons with a high degree of saturation). For the wax-free bitumen, the surface is characterised by a homogeneous distribution without chemical variations or phase structures and by a stronger signal intensity from aromatic compounds. When adding wax to the wax-free bitumen, extensive wax segregation occurs, but differently from the natural waxy bitumen, no bee structures are observed. Furthermore, fracture surfaces of all the wax-containing samples reveal circular structures, which are distinctly different from those observed on the original surfaces. The obtained chemical knowledge on bitumen surfaces and phase structures is of fundamental importance to understand performance differences of this type of materials.

  • 36.
    Mari, Luca
    et al.
    Università Cattaneo LIUC, Italy.
    Ehrlich, Charles
    NIST National Institute of Standards and Technology, US.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Measurement units as quantities of objects or values of quantities: a discussion2018In: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, no 5, p. 716-721Article in journal (Refereed)
    Abstract [en]

    Measurement units have historically been defined as quantities (i.e., specific properties) of objects, such as the mass of a particular piece of metal or the length of a particular rod. While the current International System of Units (SI) Brochure endorses this position, the draft 9th SI Brochure proposes to change it, and instead define measurement units as values of quantities. The reason for this proposed change is not provided, but it does not seem plausible that it is related to the redefinition of the SI units in terms of fundamental constants of nature: the very concept of what a unit is does not depend on the concrete way any given unit is defined. This paper is intended to open a discussion of whether measurement units should be defined as quantities or as quantity values, and provides our rationale for maintaining the definition of units as quantities.

  • 37.
    Nilsson Tengelin, Maria
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Källberg, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Effects of non-visual optical flicker in an office with two different light sources.2017In: PROCEEDINGS of the Conference on "Smarter Lighting for Better Life"at the CIE Midterm Meeting 2017., 2017, p. 451-Conference paper (Other academic)
    Abstract [en]

    LED lighting solutions sometimes give rise to optical flicker. In most cases, the temporal modulations are too fast to be perceived directly, but may still be noticed through stroboscopic effects. We report on an investigation on how people experience the lighting in an office where two LED lamps are modulated separately with different frequencies. The test subjects performed tasks for evaluation of perception, attention and reaction time. The subjects are found to be affected by the modulated light as the reaction times are shorter and the attention test scores are higher in modulated lighting compared to constant lighting. Furthermore, the study confirms that the stroboscopic effect depends on the nature of the tasks and that it is more easily perceived at lower frequencies but noticed up to at least 400 Hz.

  • 38.
    Nilsson Tengelin, Maria
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Källberg, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Hedekvist, Per Olof
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Measurement of the Effect of Dynamic Lighting on Alertness, Mood and Sleepiness2017In: PROCEEDINGS OF THE LUX EUROPA 2017, Lighting for modern society / [ed] Matej B. Kobav, University of Ljubljana, Slovenia, 2017Conference paper (Other academic)
    Abstract [en]

    The lighting in the workplace is known to have a significant effect on the workers’ well-being and alertness. It also affects sleep/wake-cycles and mood. The aim of this pilot study is to investigate a method to evaluate non-visual effects of variable lighting in workplaces using both self-assessed and physical data. The lighting in two offices was varied according to pre-programmed schedules, including daylight simulating scenario for two weeks and activity promoting scenario for two weeks. The method was successful and provided interesting results on the measured physical data. The resting pulse was lowered and the sleep quality improved for the test subjects during the weeks of dynamic office lighting.

  • 39.
    Nord, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    D6.17 Communication and Dissemination Plan M3-M12: Project: PRoPART2018Report (Other academic)
    Abstract [en]

    The

    objective of PRoPART is the development and demonstration of a high availability positioning solution for connected automated driving applications. It aims to develop and enhance an existing RTK (Real Time Kinematic) software solution developed by Waysure, by exploiting the distinguished features of Galileo signals as well as combining it with other positioning and sensor technologies. Besides the use of vehicle on board sensors, PRoPART will also use a low-cost Ultra Wideband (UWB) ranging solution for redundancy and robustness in areas where the coverage of GNSS is poor e.g. in tunnels or in urban canyons. In order to define the correct requirements for the PRoPART combined positioning solution, a cooperative automated vehicle application will be defined and developed. The vehicle application will rely on the high availability positioning solution and use it to couple its ADAS system with V2X and aggregate information received from other connected vehicles and Road Side Units (RSU).

    The main objective of WP6 Task T6.2 and Task T6.3

    is to spread PRoPART results among the main target groups identified during the development of the business plan studies. PRoPART dissemination activities aim to raise awareness about its real added value in technical terms.

    Specific objectives:

    • Definition of an agile communication strategy to be adapted to the different target groups and messages.
    • Preparation of the corporative image and a set of materials for the promotion and comprehensive dissemination.
    • Monitoring and execution of the communication plan with a continuous penetration in the main target groups with tailored messages.

    Referring to the above mentioned aims PRoPART’s Communication and Dissemination plan addresses the following key issues: identification of stakeholders and project’s key impact fields; specific dissemination tools (logo, website, publications, conferences, events, press media, leaflets and posters, videos, cooperation with other projects, social networking, etc.). Finally, it will focus on the most relevant procedures related to communication and dissemination activities

  • 40.
    Nord, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    D6.2 Project Website: Project: PRoPART2018Report (Other academic)
    Abstract [en]

    The PRoPART public website has been implemented in month 3 of the project, and will be maintained over the lifetime of the project. The internet portal works as communication platform to assist the coordination of the project and its activities.

    An individual domain has been acquired to host the website. The link to this PRoPART website is:

    http://www.propart-project.eu/

    Within the design phase of the website, perspectives from both specialized and non-specialized visitors have been considered in order to develop the interface.

    The website will be the main communication tool for the project, where all the publicly available dissemination materials will be published in a timely manner. The website is an interactive environment that will give access to all the publishable development of PRoPART. It will give a very direct link to the main results and to the hottest project news.

    Besides, this website gives a link to the objectives, partnership, activities and events related with the project, and it is planned to give access to all the aspects regarding the new technologies, best practices and recommendations for robust positioning for automated vehicles gathered from the project development. Contributions from the partners will be highly important to maintain the project’s website updated, in order to improve the website positioning in search engines and to reflect an active attitude to Internet users. In addition, partners are asked to link their website and platforms to the website of PRoPART project. In this sense, a SEO positioning analysis will be performed to ensure higher visibility in web search engines.

    The following points describe the different sections

    and functionalities of the website, supported by screenshots to better understand its use.

  • 41.
    Nord, Stefan
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    HiFi Visual Target - D5.2 Final Report2018Report (Other academic)
    Abstract [en]

    Advanced Driver Assistance Systems (ADAS) and Autonomous Driving (AD) vehicles rely heavily on sensors for achieving their goal of protecting the driver and passengers from potentially dangerous situations. Optical sensors are used to measure locations and velocities of objects at distances of up to 150 meters. Optical sensors could be cameras (for visible light or IR) used to detect either objects or road features (like e.g. road edges and markings). They are a common choice for high-end ADAS and are found in sensor sets of most AD vehicles.

    To ensure reliable performance of object detection, extensive testing of optical sensors is required. In vehicle testing performed at test tracks like AstaZero, 3D soft car targets are used for safety reasons. However, due to non-perfect shape and materials, the optical characteristics of 3D soft car targets may differ considerably from that of real vehicles in traffic, resulting in different detection performance, and hence different activation of the functions. Moreover, during tests the quality of the 3D soft car targets deteriorates due to repeated impacts and reassembly of the targets, which implies that there is a need of methods for securing the quality of the 3D soft car targets over time.

    By addressing these challenges, the goal of the project has been to contribute to improved testing methods of optical and geometrical characteristics of 3D soft car targets by:

    • developing measurement methods and specifying measurement setups for the optical and geometrical characteristics of 3D soft car targets;
    • developing simplified measurement methods for quality check on 3D soft car targets to secure the quality over time;
    • providing input to international standardization regarding methods for measurement of optical and geometrical characteristics of real and soft car targets.

    The results include test of different measurement methods, different 3D soft car targets as well as real vehicles and also an accelerated ageing test of a 3D soft car target from DRi.

  • 42.
    Nord, Stefan
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Lindgren, Mikael
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    HiFi Visual Target - Methods for Measuring Optical and Geometrical Characteristics of Soft Car Targets for ADAS and AD2017In: Lecture Notes in Mobility: Smart Systems Transforming the Automobile / [ed] Gereon Meyer, Berlin: Springer, 2017, p. 201-209Conference paper (Other academic)
    Abstract [en]

    Advanced Driver Assistance Systems (ADAS) and Automated Driving (AD)vehicles rely on a variety of sensors and among them optical sensors. Extensivetesting of functions using optical sensors is required and typically performedat proving grounds like AstaZero. Soft surrogate targets are used for safetyreasons but the optical and geometrical characteristics of soft car targets maydiffer considerably from that of real vehicles. During tests the quality of thesoft car targets deteriorates due to repeated impacts and reassembly of thetargets, and there is a need of methods for securing the quality of the softcar targets over time. One of the main goals of the HiFi Visual Target project isto develop and validate accurate and repeatable measurement methods of theoptical and geometric characteristics of soft car targets.

  • 43.
    Paridari, Kaveh
    et al.
    KTH Royal Institute of Technology, Sweden.
    Nordstrom, Lars
    KTH Royal Institute of Technology, Sweden.
    Sandels, Claes
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Aggregator strategy for planning demand response resources under uncertainty based on load flexibility modeling2017In: 2017 IEEE International Conference on Smart Grid Communications, SmartGridComm 2017, 2017, p. 338-343Conference paper (Refereed)
    Abstract [en]

    Nowadays, end-users can participate in demand response (DR) programs, and even slight load reductions from many houses can add up to major load shifts in the power system. Aggregators, which act as mediators between end-users and distribution system operator (DSO), play an important role here. The aggregator contracts the end-users for DR programs, plans ahead for times when customers should shift their load, and controls the load shifts in the running time. In this paper, our main focus is on planning the end-users for load shifting. Here, we first define and formulate the flexibilities (e.g., Stamina, repetition, and capacity) related to the dynamic loads such as space heating systems (SHSs) in detached houses. Assuming some end-users being contracted for DR program, based on estimation of their house characteristics and load flexibilities, an algorithm is then proposed to plan the SHSs for load shifting. In this algorithm the states in which a flexible load can be planned, kept in backup, or unavailable are considered by the aggregator. Another algorithm has been proposed here to deal with the different sources of uncertainties (which cause some of the planned SHSs to become unavailable). Numerical results are presented at the end, which discuss performance of the proposed strategy in terms of load flexibilities, load shifts in response to DR signals, and sensitivity analysis. Here, how to estimate the houses characteristics is a difficult issue, and we approximate them based on available models in the literature.

  • 44.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Assuring measurement quality in person-centred healthcare2018In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 29, p. 034003-Article in journal (Refereed)
    Abstract [en]

    Is it realistic to aspire to the same kind of quality-assurance of measurement in person-centred care, currently being implemented in healthcare globally, as is established in the physical sciences and engineering? Ensuring metrological comparability (‘traceability’) and reliably declaring measurement uncertainty when assessing patient ability or increased social capital are however challenging for subjective measurements often characterised by large dispersion. Drawing simple analogies between ‘instruments’ in the social sciences – questionnaires, ability tests, etc.–  and  engineering instruments such as thermometers does not go far enough. A possible way forward apparently equally applicable to both physical and social measurement, seems to be to model inferences in terms performance metrics of a measurement system. Person-centred care needs person-centred measurement and a full picture of the measurement process when Man acts as a measurement instrument is given in the present paper. This complements previous work by presenting the process, step by step, from the observed indication (e.g. probability of success, Psuccess, of achieving atask), through restitution with Rasch Measurement Theory, to the measurand (e.g. task difficulty). Rasch invariant measure theory can yield quantities –‘latent’ (or ‘explanatory’) variables such as task challenge or person ability – with characteristics akin to those of physical quantities. Metrological references for comparability via traceability and reliable estimates ofuncertainty and decision risks are then in reach even for perceptive measurements (and other qualitative properties). As a case study, the person-centred measurement of cognitive ability is examined, as part of the EUproject EMPIR 15HLT04 NeuroMet, for Alzheimer’s, where better analysis of correlations with brain atrophy is enabled thanks to the Rasch metrological approach.

  • 45.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Assuring quality in person-centred healthcare2017Conference paper (Other academic)
  • 46.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    How to calibrate a questionnaire: quality-assuring categorical data with psychometric measurement theory2018In: / [ed] Charité, 2018Conference paper (Other academic)
    Abstract [en]

    Measurements in the social sciences – with ‘instruments’ such as questionnaires, ability tests, – in education, healthcare and so on, need metrological quality assurance. A patient, for instance, expects the same quality of care wherever and whenever provided. This is a challenge since the usual tools of statistics do not always work on the categorical scales typical of such measurements. Modelling a measurement system where the instrument is a human being, and where the output is a performance metric, i.e., how well the set-up performs an assessment, appears to be a way forward. This BEMC Colloquium will present the necessary tools, such as psychometric Rasch measurement theory, and will be followed by a hands-on workshop where you yourselves can analyse cases such as (i) the Quality of the BEMC Colloquium Series and (ii) a Healthy Lifestyle.

  • 47.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Limits to the reliability of the Rasch psychometric model2017Conference paper (Other academic)
    Abstract [en]

    Metrological assurance of qualitative evaluations, such as made by a person acting as a Measurement Instrument (e.g. in person-centred care) seems to be possible using a generalised linear model specifically based on the Rasch psychometric approach. Traditional classical test theory and many of the usual tools of statistics cannot work reliably on ordinal or nominal scales typical of person responses, rating questionnaires or other qualitative evaluations. This talk recalls how to establish metrological references (item banks of task difficulty, for example) and uncertainty budgets for categorical data (using informational entropy). New insight will then be given into how the reliability of subjective measurement systems and the Rasch model can be evaluated with respect to measurement scale shift and scale stretching with novel tools analysing rating scores and logistic regression residuals. Examples will range from physical rehabilitation to cognitive assessment.

  • 48.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Metrological qualityassurance in person-centred healthcare and other qualitative observations2017In: Abteilung 8: Medizinphysik und metrologische Informationstechnik, Berlin, 2017Conference paper (Other academic)
    Abstract [en]

    Measurements with categorical data – produced with ‘instruments’ such as questionnaires, ability tests, – in education, healthcare and so on, need metrological quality assurance. A patient expects that the quality of care will be comparable wherever and whenever care is provided, but metrological quality assurance has yet to be developed in many cases. When seeking an increased stringency in measurement where human perception is a key factor, ensuring metrological comparability (‘traceability’) and reliably declaring measurement uncertainty when assessing patient ability, service satisfaction or material hardness are challenging. Subjective measurements are often characterised by large dispersion; the usual tools of statistics do not always work on the categorical and ordinal scales typical of such measurements; and an independent objective reality in what is being measured might be questioned. Drawing simple analogies between engineering instruments such as thermometers and social instruments such as questionnaires merely in terms of measurement error does not go far enough when attempting to introduce metrology to qualitative observations (examinations, assessments, opinions). Modelling inferences of a measurement system where the instrument is a human being, and where the output of the instrument in response to probing an object (‘entity’) is a performance metric, i.e., how well the set-up performs the assessment, does appear to be a way forward. Be it decision risks arising from measurement uncertainty or responses to a cognitive test in a clinic for Alzheimer patients, a psychometric, generalised linear model can yield quantities, ‘latent’ (or ‘explanatory’) variables, – task challenge or person ability – which seem to possess quantitative characteristics akin to those of physical quantities. Metrological references for comparability via traceability and reliable estimates of uncertainty and decision risks are then in reach even for perceptive measurements. Metrological quality assurance in person-centred healthcare is being developed for sufferers in cases such as Myotonic Dystrophy and Alzheimer’s disease, as studied in the EMPIR 15HLT04 NeuroMet project

  • 49.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Metrology and sustainability accounting standards2018In: The New Algorithm: Setting a new market standardfor financial systems, Stockholm, 2018Conference paper (Other (popular science, discussion, etc.))
  • 50.
    Pendrill, Leslie
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Metrology of categorical data in psychometrics2017Conference paper (Other academic)
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