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Publications (10 of 17) Show all publications
Lin, J., Hedekvist, P. O., Mylly, N., Bollen, M., Shen, J., Xiong, J. & Silfvenius, C. (2024). Human-Centric and Integrative Lighting Asset Management in Public Libraries: Qualitative Insights and Challenges From a Swedish Field Study. IEEE Access, 12, 40905-40921
Open this publication in new window or tab >>Human-Centric and Integrative Lighting Asset Management in Public Libraries: Qualitative Insights and Challenges From a Swedish Field Study
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2024 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 12, p. 40905-40921Article in journal (Refereed) Published
Abstract [en]

Traditional reliability evaluation of lighting sources often assesses only 50% of a lamp’s volume, which can lead to performance disparities and misapplications due to their limited reflection of real-world scenarios. To address the limitations, it is essential to adopt advanced asset management approaches that enhance awareness and provide a more comprehensive evaluation framework. This paper delves into the nuances of human-centric and integrative lighting asset management in Swedish public libraries, employing a qualitative field study to ascertain the alignment of current practices with these advanced lighting principles. Expanding library services to 20 high-latitude locations (>55° N) in Sweden, our research employed field observations, stakeholder interviews, and questionnaires, coupled with a thorough gap analysis, to understand the current landscape and stakeholder perceptions. Our findings reveal a dichotomy between the existing conditions of library lighting and the stakeholders’ experiences and expectations. Despite the intention to create conducive environments, there is a clear disconnect, with overt problems and covert challenges affecting user satisfaction and efficacy of lighting management. Managers, staff, and users reported varied concerns, including eye strain and discomfort, indicative of substantial room for improvement. The study advocates for a paradigm shift in not only lighting asset management but also reliability evaluation of lighting sources, moving toward continuous improvement, and enhanced awareness and training on human-centric and integrative lighting principles.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2024
Keywords
Asset management; Human computer interaction; Human resource management; Libraries; Lighting; Assets management; Continuous improvements; Human-centric; Human-centric lighting; Integrative lighting; Library buildings; Lighting asset management; Lighting controls; Non visuals; Reliability of lighting source; Visual and non-visual performance; Visual performance; Reliability
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-72919 (URN)10.1109/ACCESS.2024.3377135 (DOI)2-s2.0-85188464082 (Scopus ID)
Funder
Swedish Energy Agency, P2022-00277
Note

This work was supported by Swedish Energy Agency through the Project ‘‘Integrated Lighting Asset Management in Public Libraries through Digital Twins (Integrerad Tillgångsförvaltning för Belysning i Allmänna Bibliotek Genom Digital Tvilling)’’ under Project P2022-00277.

Available from: 2024-04-26 Created: 2024-04-26 Last updated: 2024-04-26Bibliographically approved
Dimarcq, N., Hedekvist, P. O., Rieck, C. & Ashby, N. (2024). Roadmap towards the redefinition of the second. Metrologia, 61(1), Article ID 012001.
Open this publication in new window or tab >>Roadmap towards the redefinition of the second
2024 (English)In: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 61, no 1, article id 012001Article in journal (Refereed) Published
Abstract [en]

This paper outlines the roadmap towards the redefinition of the second, which was recently updated by the CCTF Task Force created by the CCTF in 2020. The main achievements of optical frequency standards (OFS) call for reflection on the redefinition of the second, but open new challenges related to the performance of the OFS, their contribution to time scales and UTC, the possibility of their comparison, and the knowledge of the Earth’s gravitational potential to ensure a robust and accurate capacity to realize a new definition at the level of 10−18 uncertainty. The mandatory criteria to be achieved before redefinition have been defined and their current fulfilment level is estimated showing the fields that still needed improvement. The possibility to base the redefinition on a single or on a set of transitions has also been evaluated. The roadmap indicates the steps to be followed in the next years to be ready for a sound and successful redefinition.

Place, publisher, year, edition, pages
Institute of Physics, 2024
Keywords
atomic frequency standard, International System of Units, second, Atomic frequency standards, Gravitational potential, Optical frequency standard, Performance, Redefinition of the seconds, Roadmap, Task force, Time-scales, Uncertainty, Frequency standards
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:ri:diva-71948 (URN)10.1088/1681-7575/ad17d2 (DOI)2-s2.0-85184256113 (Scopus ID)
Available from: 2024-02-27 Created: 2024-02-27 Last updated: 2024-02-27Bibliographically approved
Pollinger, F., Baselga, S., Courde, C., Eschelbach, C., García-Asenjo, L., Garrigues, P., . . . Wiśniewski, M. (2023). The European GeoMetre project: developing enhanced large-scale dimensional metrology for geodesy. Applied Geomatics
Open this publication in new window or tab >>The European GeoMetre project: developing enhanced large-scale dimensional metrology for geodesy
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2023 (English)In: Applied Geomatics, ISSN 1866-9298Article in journal (Refereed) Epub ahead of print
Abstract [en]

We provide a survey on the joint European research project “GeoMetre”, which explores novel technologies and their inclusion to existing surveying strategies to improve the traceability of geodetic reference frames to the SI definition of the metre. This work includes the development of novel distance meters with a range of up to 5 km, the realisation of optical multilateration systems for large structure monitoring at an operation distance of 50 m and beyond, and a novel strategy for GNSS-based distance determination. Different methods for refractivity compensation, based on classical sensors, on dispersion, on spectroscopic thermometry, and on the speed of sound to reduce the meteorological uncertainties in precise distance measurements, are developed further and characterised. These systems are validated at and applied to the novel European standard baseline EURO5000 at the Pieniny Kippen Belt, Poland, which was completely refurbished and intensely studied in this project. We use our novel instruments for a reduced uncertainty of the scale in the surveillance networks solutions for local tie measurements at space-geodetic co-location stations. We also investigate novel approaches like close-range photogrammetry to reference point determination of space-geodetic telescopes. Finally, we also investigate the inclusion of the local gravity field to consider the deviations of the vertical in the data analysis and to reduce the uncertainty of coordinate transformations in this complex problem. 

Place, publisher, year, edition, pages
Springer Science and Business Media Deutschland GmbH, 2023
Keywords
Air refractivity compensation, GeoMetre, GNSS-EDM comparison, Local tie metrology, Multilateration systems, Novel distance sensor systems, SI traceability
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-64105 (URN)10.1007/s12518-022-00487-3 (DOI)2-s2.0-85148476120 (Scopus ID)
Note

Funding details: Horizon 2020 Framework Programme, H2020; Funding details: European Metrology Programme for Innovation and Research, EMPIR; Funding text 1: Open Access funding enabled and organized by Projekt DEAL. This project 18SIB01 GeoMetre has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.

Available from: 2023-02-28 Created: 2023-02-28 Last updated: 2023-12-20Bibliographically approved
Hedekvist, P. O., Ebenhag, S.-C., Rieck, C., Wallberg, D. & Bergroth, M. (2022). Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network. In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings: . Paper presented at 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Fiber Optic Time Transfer from UTC(k) to a VLBI Antenna in a Coherent Communication Network
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2022 (English)In: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2022Conference paper, Published paper (Refereed)
Abstract [en]

The local time scale at Onsala Space Observatory is connected to UTC(SP) through a White Rabbit time transfer system operating on the Swedish University Computer Network SUNET. The time transfer enables a robust synchronization of the VLBI and the IGS stations operating at the observatory and can potentially improve the reliability and availability of traceable time at sufficient accuracy. Several months of data are gathered to evaluate long term events and stability metrics. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2022
Keywords
fiber, synchronization, time dissemination, WDM, White rabbit, Observatories, Coherent communication, Communications networks, Fiber-optics, Local time, Onsala Space Observatory, Time transfer, Time-scales, Transfer systems, Computer operating systems
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-60159 (URN)10.1109/EFTF/IFCS54560.2022.9850949 (DOI)2-s2.0-85137355028 (Scopus ID)9781665497183 (ISBN)
Conference
2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022, 24 April 2022 through 28 April 2022
Note

Funding details: Horizon 2020 Framework Programme, H2020; Funding details: Horizon 2020; Funding text 1: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union’s Horizon 2020 Research and Innovation Program.; Funding text 2: This work was supported by the TiFOON 18SIB06 Project through the EMPIR Programme co-financed by the Participating States and through the European Union's Horizon 2020 Research and Innovation Program.

Available from: 2022-10-10 Created: 2022-10-10 Last updated: 2023-06-08Bibliographically approved
Rieck, C., Jaldehag, K., Ebenhag, S.-C., Jarlemark, P. & Hedekvist, P. O. (2020). Time and frequency laboratory activities at RISE. In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI: . Paper presented at 51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020 (pp. 169-180). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Time and frequency laboratory activities at RISE
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2020 (English)In: Proceedings of the Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI, Institute of Electrical and Electronics Engineers Inc. , 2020, p. 169-180Conference paper, Published paper (Refereed)
Abstract [en]

RISE Research Institutes of Sweden is since 2018 the result of a rebranding of SP Technical Research Institute of Sweden and several other national research facilities and test beds in Sweden. This also comprises most national metrology institute (NMI) activities, including time and frequency that is still located at its Borås facilities in the southwest of Sweden since 1995. UTC(SP) remains the official designation of the Swedish UTC(k) realization. It is realized in a classical master clock and phase stepper setup and is locally distributed to different users and time transfer applications. The most recent local clock ensemble consists of four hydrogen masers and three high performance 5071A Cs standards. UTC(SP) is linked to TAI using TWSTFT and GNSS. The primary link is a combination TWGPPP with current calibration uncertainties of 1.1 ns. The time scale is regularly kept within ±5 ns of UTC. RISE has also established several distributed UTC(SP) copies, with both local backups in Borås and facilities at remote sites linked together by GNSS time transfer. Network time distribution at those sites make UTC(SP) publicly available. Additionally, RISE offers several calibration services for the distribution of UTC-traceable time and frequency signals. Time and frequency related metrological research at RISE is mostly concentrated on further refinement of GNSS and TWSTFT methods, their calibration and the dissemination using those methods. We are also active in research on fiber based optical time and frequency transfer. Outside the metrological responsibilities, many research projects focus on establishing metrological aspects of time and frequency within for instance the automotive and maritime domain.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2020
Keywords
Clocks, Hydrogen masers, Time measurement, Calibration uncertainty, National metrology institutes, Research facilities, Research institutes, Technical research, Time and frequencies, Time and frequency transfers, Time distribution, Calibration
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-44903 (URN)10.33012/2020.17297 (DOI)2-s2.0-85081552388 (Scopus ID)0936406259 (ISBN)
Conference
51st Annual Precise Time and Time Interval Systems and Applications Meeting, PTTI 2020, 21 January 2020 through 24 January 2020
Note

Funding details: National Measurement Institute, NMI; Funding details: VINNOVA; Funding text 1: RISE has inherited the function of the Swedish NMI from SP Technical Research Institute of Sweden in 2018 when the RISE institutes Innventia, Swerea, SP and Swedish ICT merged to create a stronger research and innovation partner for businesses and society. The intention is to make industrial research institutes internationally more competitive and to facilitate continued sustainable growth in Sweden by strengthening competitiveness and renewal in the business community [1]. RISE is appointed as the Swedish NMI by the Ministry of Enterprise and Innovation. The NMI is funded from Vinnova [2], Sweden’s innovation agency and any strategic decisions are made by an advisory board composed of experts from Swedish industry. Vinnova decides the level of NMI funding and also the Swedish level of participation in European funded research of the EMPIR program and its possible successor.; Funding text 2: This report was supported by the Swedish National Metrology Program, program owner Swedish Agency for Innovation Systems (VINNOVA). We acknowledge the work of the BIPM, the CCTF and EURAMET, further the Swedish Post and Telecom Authority (PTS) who finances critical Swedish communication infrastructure and thereby strengthens resiliency in national timing.

Available from: 2020-05-20 Created: 2020-05-20 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Rieck, C., Bergroth, M., Krehlik, P. & Sliwczynski, L. (2019). Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network. In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Evaluation of Fiber Optic Time and Frequency Distribution System in a Coherent Communication Network
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2019 (English)In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

A fiber-based time transfer between UTC(SP) and the VLBI-station at Onsala Space Observatory has been evaluated. The transfer uses a single wavelength in an active coherent DWDM-network in unidirectional duplex fibers and is routed through Reconfigurable Optical Add-Drop Multiplexers.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
fiber optics, time dissemination, traceable, Coherent communication, DWDM networks, Onsala Space Observatory, Reconfigurable optical add-drop multiplexer, Single wavelength, Time and frequencies, Fibers
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40617 (URN)10.1109/FCS.2019.8856039 (DOI)2-s2.0-85073779075 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Note

Funding text 1: This work was supported by 15SIB05-OFTEN, which has received funding from the EMPIR programme co-financed by the Participating States within Euramet and from the European Union's Horizon 2020 research and innovation programme.

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Jarlemark, P. & Sundblad, R. (2019). Redundant Distributed Timescale Traceable to UTC(SP). In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings: . Paper presented at 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019. Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Redundant Distributed Timescale Traceable to UTC(SP)
2019 (English)In: IFCS/EFTF 2019 - Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper, Published paper (Refereed)
Abstract [en]

A variety of commerce needs or requires accurate time, such as air traffic control, bank transactions and computer log file comparisons. Whenever the used time needs to be compared with a timestamp generated by another system, both systems must be traceable to a common reference, such as a local UTC(k) realization. Within this paper a distributed timescale using five nodes across Sweden is presented. The foundation for time keeping at each node is two cesium clocks, which are connected to time analysis equipment and equipment for producing redundant timescales. Both timescales are used and distributed throughout the time node and then prioritized by the local NTP servers, PTP grand masters, and other time distribution services. The timescales are monitored by RISE Research Institute of Sweden to ensure traceability to UTC(SP).To compare the timescales of each location with the other locations, GNSS common view is primarily used with an alternative fiber-based solution as back-up. All available time signals are measured relative to the master timescale, and that data is distributed to the other locations to be used as input in the steering of the local timescales. The NTP servers of the time nodes are directly connected to Internet Exchange points, for central, highly available and fair connectivity to the Internet. 

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2019
Keywords
holdover, redundant, robust, time dissemination, traceable, Location, Air traffic control
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-40616 (URN)10.1109/FCS.2019.8856058 (DOI)2-s2.0-85073793374 (Scopus ID)9781538683057 (ISBN)
Conference
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum, IFCS/EFTF 2019, 14 April 2019 through 18 April 2019
Note

Funding text 1: The project was funded by the Swedish Post and Telecom Authority (PTS).

Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2023-06-08Bibliographically approved
Hedekvist, P. O., Weddig, L. & Ebenhag, S. C. (2018). Analysis and compensation of polarization in an optical frequency transfer through a fiber communication network. In: : . Paper presented at 2018 European Frequency and Time Forum (EFTF) (pp. 253-256).
Open this publication in new window or tab >>Analysis and compensation of polarization in an optical frequency transfer through a fiber communication network
2018 (English)Conference paper, Published 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.

Keywords
Optical fiber networks, Optical fiber polarization, Optical fiber amplifiers, Optical variables measurement, fiber, frequency transfer, heterodyne detection, coherent, polarization
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34324 (URN)10.1109/EFTF.2018.8409044 (DOI)2-s2.0-85050721935 (Scopus ID)
Conference
2018 European Frequency and Time Forum (EFTF)
Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2023-06-05Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O. & Weddig, L. (2018). Measurement and Analysis of Polarization Variations in an Optical Coherent Fiber Communication Network Utilized for Time and Frequency Distribution. In: : . Paper presented at 49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia, USA (pp. 233-236).
Open this publication in new window or tab >>Measurement and Analysis of Polarization Variations in an Optical Coherent Fiber Communication Network Utilized for Time and Frequency Distribution
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

When fiber optic communication networks are used for ultra-stable timing or frequency transfer, there will always be an influence of polarization variation to some extent. The variations can be induced by e.g. mechanical vibration or electromagnetic effects from adjacent power lines. The output polarization from a 120 km fiber transmission of an ultra-stable optical frequency is analyzed and the requirements of a compensation device are quantified.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-37576 (URN)10.33012/2018.15620 (DOI)2-s2.0-85050771424 (Scopus ID)
Conference
49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia, USA
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2023-06-08Bibliographically approved
Ebenhag, S.-C., Hedekvist, P. O., Liström, S. & Bergroth, M. (2017). Time and Frequency Dissemination in an All-optical Coherent Fiber Communication Network. In: : . Paper presented at 48th Annual Precise Time and Time Interval Systems and Applications Meeting January 30 - 2, 2017 Hyatt Regency Monterey Monterey, California, USA (pp. 306-311). Institute of Navigation
Open this publication in new window or tab >>Time and Frequency Dissemination in an All-optical Coherent Fiber Communication Network
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

A nationwide fiber optic communication network utilizing state-of-the-art technologies with data modulation both in the polarization and in multi-level amplitude and phase is being deployed in Sweden. The network is operated by the Swedish University computer Network, and connects all universities and several research facilities in the country through redundant connections. Since there is a limited amount of clients connected to the network, each client will be assigned a personal wavelength. With a network that is all-optical through an advanced utilization of dynamically reconfigurable optical add and drop multiplexers, each wavelength can theoretically be connected to any other client within the network, enabling broadcasting on allocated wavelengths. The coherent modulation formats also enables signal recovery through electronic digital signal processing after detection, and no optical dispersion compensation is thereby installed. This new network scheme enables a brand new implementation of frequency and time dissemination in the network. The omission of dispersion compensation fibers enhances the symmetry in duplex fiber pair transmission. These optical add-drop installations allow for future efficient frequency and time signal broadcasting from reference nodes operated by distributors such as SP Technical Research Institute of Sweden to users connected to the network.

Place, publisher, year, edition, pages
Institute of Navigation, 2017
Keywords
Broadcasting, Digital signal processing, Dispersion compensation, Drops, Fibers, Light transmission, Modulation, Signal reconstruction, Dispersion-compensation fibers, Fiber communication networks, Fiber optic communications, Optical dispersion compensation, Redundant connections, Research facilities, State-of-the-art technology, Time and frequency disseminations
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:ri:diva-37577 (URN)10.33012/2017.14975 (DOI)2-s2.0-85047021729 (Scopus ID)
Conference
48th Annual Precise Time and Time Interval Systems and Applications Meeting January 30 - 2, 2017 Hyatt Regency Monterey Monterey, California, USA
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2023-06-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0801-3124

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