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Author Stone, J.E.; Phillips, A.J.K.; Ftouni, S.; Magee, M.; Howard, M.; Lockley, S.W.; Sletten, T.L.; Anderson, C.; Rajaratnam, S.M.W.; Postnova, S.
Title (up) Generalizability of A Neural Network Model for Circadian Phase Prediction in Real-World Conditions Type Journal Article
Year 2019 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 9 Issue 1 Pages 11001
Keywords Human Health; Instrumentation
Abstract A neural network model was previously developed to predict melatonin rhythms accurately from blue light and skin temperature recordings in individuals on a fixed sleep schedule. This study aimed to test the generalizability of the model to other sleep schedules, including rotating shift work. Ambulatory wrist blue light irradiance and skin temperature data were collected in 16 healthy individuals on fixed and habitual sleep schedules, and 28 rotating shift workers. Artificial neural network models were trained to predict the circadian rhythm of (i) salivary melatonin on a fixed sleep schedule; (ii) urinary aMT6s on both fixed and habitual sleep schedules, including shift workers on a diurnal schedule; and (iii) urinary aMT6s in rotating shift workers on a night shift schedule. To determine predicted circadian phase, center of gravity of the fitted bimodal skewed baseline cosine curve was used for melatonin, and acrophase of the cosine curve for aMT6s. On a fixed sleep schedule, the model predicted melatonin phase to within +/- 1 hour in 67% and +/- 1.5 hours in 100% of participants, with mean absolute error of 41 +/- 32 minutes. On diurnal schedules, including shift workers, the model predicted aMT6s acrophase to within +/- 1 hour in 66% and +/- 2 hours in 87% of participants, with mean absolute error of 63 +/- 67 minutes. On night shift schedules, the model predicted aMT6s acrophase to within +/- 1 hour in 42% and +/- 2 hours in 53% of participants, with mean absolute error of 143 +/- 155 minutes. Prediction accuracy was similar when using either 1 (wrist) or 11 skin temperature sensor inputs. These findings demonstrate that the model can predict circadian timing to within +/- 2 hours for the vast majority of individuals on diurnal schedules, using blue light and a single temperature sensor. However, this approach did not generalize to night shift conditions.
Address School of Physics, University of Sydney, Sydney, New South Wales, Australia
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:31358781; PMCID:PMC6662750 Approved no
Call Number GFZ @ kyba @ Serial 2667
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Author Alamús, R.; Bará, S.; Corbera, J.; Escofet, J.; Palà , V.; Pipia, L.; Tardà, A.
Title (up) Ground-based hyperspectral analysis of the urban nightscape Type Journal Article
Year 2017 Publication ISPRS Journal of Photogrammetry and Remote Sensing Abbreviated Journal ISPRS Journal of Photogrammetry and Remote Sensing
Volume 124 Issue Pages 16-26
Keywords Instrumentation; Remote Sensing
Abstract Airborne hyperspectral cameras provide the basic information to estimate the energy wasted skywards by outdoor lighting systems, as well as to locate and identify their sources. However, a complete characterization of the urban light pollution levels also requires evaluating these effects from the city dwellers standpoint, e.g. the energy waste associated to the excessive illuminance on walls and pavements, light trespass, or the luminance distributions causing potential glare, to mention but a few. On the other hand, the spectral irradiance at the entrance of the human eye is the primary input to evaluate the possible health effects associated with the exposure to artificial light at night, according to the more recent models available in the literature. In this work we demonstrate the possibility of using a hyperspectral imager (routinely used in airborne campaigns) to measure the ground-level spectral radiance of the urban nightscape and to retrieve several magnitudes of interest for light pollution studies. We also present the preliminary results from a field campaign carried out in the downtown of Barcelona.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0924-2716 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1613
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Author Su, Z.; Zhong, X.; Zhang, G.; Li, Y.; He, X.; Wang, Q.; Wei, Z.; He, C.; Li, D.
Title (up) High Sensitive Night-time Light Imaging Camera Design and In-orbit Test of Luojia1-01 Satellite Type Journal Article
Year 2019 Publication Sensors Abbreviated Journal Sensors
Volume 19 Issue 4 Pages 797
Keywords Remote Sensing; Instrumentation
Abstract Luojia1-01 satellite is the first scientific experimental satellite applied for night-time light remote sensing data acquisition, and the payload is an optical camera with high sensitivity, high radiation measurement accuracy and stable elements of interior orientation. At the same time, a special shaped hood is designed, which significantly improved the ability of the camera to suppress stray light. Camera electronics adopts the integrated design of focal plane and imaging processing, which greatly reduces the volume and weight of the system. In this paper, the design of the optical camera is summarized, and the results of in-orbit imaging performance tests are analyzed. The results show that the dynamic modulation transfer function (MTF) of the camera is better than 0.17, and the SNR is better than 35 dB under the condition of 10 lx illuminance and 0.3 reflectivity and all indicators meet the design requirements. The data obtained have been widely applied in many fields such as the process of urbanization, light pollution analysis, marine fisheries detection and military.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1424-8220 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2215
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Author Wahl, F.; Kantermann, T.; Amft, O.
Title (up) How much Light do you get? Estimating Daily Light Exposure using Smartphones Type Conference Article
Year 2014 Publication Proceedings of the 2014 ACM International Symposium on Wearable Computers Abbreviated Journal Proc. of the 2014 ACM International Symposium on Wearable Computers
Volume n/a Issue n/a Pages 43-46
Keywords Instrumentation; light exposure; context inference, light intensity; light intake; circadian clock; circadian rhythm; mobile sensing
Abstract We present an approach to estimate a persons light exposure using smartphones. We used web-sourced weather reports combined with smartphone light sensor data, time of day, and indoor/outdoor information, to estimate illuminance around the user throughout a day. Since light dominates every human’s circadian rhythm and influences the sleep-wake cycle, we developed a smartphone-based system that does not re- quire additional sensors for illuminance estimation. To evaluate our approach, we conducted a free-living study with 12 users, each carrying a smartphone, a head-mounted light reference sensor, and a wrist-worn light sensing device for six consecutive days. Estimated light values were compared to the head-mounted reference, the wrist-worn device and a mean value estimate. Our results show that illuminance could be estimated at less than 20% error for all study participants, outperforming the wrist-worn device. In 9 out of 12 participants the estimation deviated less than 10% from the reference measurements.
Address ACTLab, Chair of Sensor Technology, University of Passau (florian.wahl@uni-passau.de)
Corporate Author Thesis
Publisher ACM Place of Publication Editor
Language English Summary Language English Original Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1206
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Author Kruse, F.A.; Elvidge, C.D.
Title (up) Identifying and mapping night lights using imaging spectrometry Type Journal Article
Year 2011 Publication Proceedings of Aerospace Conference, 2011 IEEE, March 5-11 2011. Abbreviated Journal
Volume Issue Pages 1 - 6
Keywords Instrumentation
Abstract Remote mapping of night lights using the Defense Meteorological Satellite Program (DMSP) has been used for decades to inventory the global distribution of human activity. ©± The coarse spatial and spectral resolution of DMSP, however, has precluded discrimination of lighting types or spectral characteristics. Recent demonstrations using photography from the International Space Station and airborne multispectral simulations demonstrate significant potential, but high-spectral-resolution field and laboratory measurements indicate that these methods do not take full advantage of the spectral information available. This research demonstrates the use of imaging spectrometer data to identify, characterize, and map urban lighting based on comparison to a lights spectral library. The library provides information about spectral emission lines unique to specific lighting types. ProSpecTIR-VS imaging spectrometer data of Las Vegas, Nevada were analyzed to extract spectral features and these were compared to the spectral library measurements on a pixel-by-pixel basis, resulting in a detailed spatial map showing different lighting types. The nature and distribution of lights can be used as a surrogate for characterization of urban settings, and measurement of urban development.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 470
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