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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. url  doi
openurl 
  Title 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  
  Publisher Place of Publication Editor  
  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  
Permanent link to this record
 

 
Author Zhang, K.; Zhong, X.; Zhang, G.; Li, D.; Su, Z.; Meng, Y.; Jiang, Y. url  doi
openurl 
  Title Thermal Stability Optimization of the Luojia 1-01 Nighttime Light Remote-Sensing Camera's Principal Distance Type Journal Article
  Year 2019 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)  
  Volume 19 Issue 5 Pages 990  
  Keywords Instrumentation; Luojia 1-01; nighttime light remote-sensing camera; principal distance; optical-passive athermal design; thermal stability  
  Abstract The instability of the principal distance of the nighttime light remote-sensing camera of the Luojia 1-01 satellite directly affects the geometric accuracy of images, consequently affecting the results of analysis of nighttime light remote-sensing data. Based on the theory of optical passive athermal design, a mathematical model of optical-passive athermal design for principal distance stabilization is established. Positive and negative lenses of different materials and the mechanical structures of different materials are matched to optimize the optical system. According to the index requirements of the Luojia 1-01 camera, an image-telecentric optical system was designed under the guidance of the established mathematical model. In the temperature range of -20 degrees C to +60 degrees C, the principal distance of the system changes from -0.01 mum to +0.28 mum. After on-orbit testing, the geometric accuracy of the designed nighttime light remote-sensing camera is better than 0.20 pixels and less than index requirement of 0.3 pixels, which indicating that the principal distance maintains good stability on-orbit and meets the application requirements of nighttime light remote sensing.  
  Address School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China. jiangyh@whu.edu.cn  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English 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 PMID:30813556 Approved no  
  Call Number GFZ @ kyba @ Serial 2238  
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Author Zhang, G.; Li, L.; Jiang, Y.; Shen, X.; Li, D. url  doi
openurl 
  Title On-Orbit Relative Radiometric Calibration of the Night-Time Sensor of the LuoJia1-01 Satellite Type Journal Article
  Year 2018 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)  
  Volume 18 Issue 12 Pages  
  Keywords Instrumentation; Remote Sensing  
  Abstract The LuoJia1-01 satellite can acquire high-resolution, high-sensitivity nighttime light data for night remote sensing applications. LuoJia1-01 is equipped with a 4-megapixel CMOS sensor composed of 2048 x 2048 unique detectors that record weak nighttime light on Earth. Owing to minute variations in manufacturing and temporal degradation, each detector's behavior varies when exposed to uniform radiance, resulting in noticeable detector-level errors in the acquired imagery. Radiometric calibration helps to eliminate these detector-level errors. For the nighttime sensor of LuoJia1-01, it is difficult to directly use the nighttime light data to calibrate the detector-level errors, because at night there is no large-area uniform light source. This paper reports an on-orbit radiometric calibration method that uses daytime data to estimate the relative calibration coefficients for each detector in the LuoJia1-01 nighttime sensor, and uses the calibrated data to correct nighttime data. The image sensor has a high dynamic range (HDR) mode, which is optimized for day/night imaging applications. An HDR image can be constructed using low- and high-gain HDR images captured in HDR mode. Hence, a day-to-night radiometric reference transfer model, which uses daytime uniform calibration to calibrate the detector non-uniformity of the nighttime sensor, is herein built for LuoJia1-01. Owing to the lack of calibration equipment on-board LuoJia1-01, the dark current of the nighttime sensor is calibrated by collecting no-light desert images at new moon. The results show that in HDR mode (1) the root mean square of mean for each detector in low-gain (high-gain) images is better than 0.04 (0.07) in digital number (DN) after dark current correction; (2) the DN relationship between low- and high-gain images conforms to the quadratic polynomial mode; (3) streaking metrics are better than 0.2% after relative calibration; and (4) the nighttime sensor has the same relative correction parameters at different exposure times for the same gain parameters.  
  Address State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China. drli@whu.edu.cn  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English 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 PMID:30513817 Approved no  
  Call Number GFZ @ kyba @ Serial 2125  
Permanent link to this record
 

 
Author Li, X.; Zhao, L.; Li, D.; Xu, H. url  doi
openurl 
  Title Mapping Urban Extent Using Luojia 1-01 Nighttime Light Imagery Type Journal Article
  Year 2018 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)  
  Volume 18 Issue 11 Pages  
  Keywords Instrumentation; Remote Sensing  
  Abstract Luojia 1-01 satellite, launched on 2 June 2018, provides a new data source of nighttime light at 130 m resolution and shows potential for mapping urban extent. In this paper, using Luojia 1-01 and VIIRS nighttime light imagery, we compared several methods for extracting urban areas, including Human Settlement Index (HSI), Simple Thresholding Segmentation (STS) and SVM supervised classification. According to the accuracy assessment, the HSI method using LJ1-01 data had the best performance in urban extent extraction, which presented the largest Kappa Coefficient value, 0.834, among all the results. For the urban areas extracted by VIIRS based HSI method, the largest Kappa Coefficient value was 0.772. In contrast, the largest Kappa Coefficient values obtained by STS method were 0.79 and 0.7512 respectively when using LJ1-01 and VIIRS data, while for SVM method the values were 0.7829 and 0.7486 when using Landsat-LJ and Landsat-VIIRS composite data respectively. The experimented results demonstrated that the utilization of nighttime light imagery can largely improve the accuracy of urban extent extraction and LJ1-01 data, with a higher resolution and more abundant spatial information, can lead to better identification results than its predecessors.  
  Address Key Laboratory of the Ministry of Land and Resources for Law Evaluation Engineering, Wuhan 430074, China. xuhuimin1985_2008@163.com  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English 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 PMID:30380616 Approved no  
  Call Number GFZ @ kyba @ Serial 2056  
Permanent link to this record
 

 
Author Gaydecki, P. url  doi
openurl 
  Title Automated moth flight analysis in the vicinity of artificial light Type Journal Article
  Year 2018 Publication Bulletin of Entomological Research Abbreviated Journal Bull Entomol Res  
  Volume 109 Issue 1 Pages 127-140  
  Keywords Instrumentation; Animals  
  Abstract Instrumentation and software for the automated analysis of insect flight trajectories is described, intended for quantifying the behavioural dynamics of moths in the vicinity of artificial light. For its time, this moth imaging system was relatively advanced and revealed hitherto undocumented insights into moth flight behaviour. The illumination source comprised a 125 W mercury vapour light, operating in the visible and near ultraviolet wavelengths, mounted on top of a mobile telescopic mast at heights of 5 and 7.1 m, depending upon the experiment. Moths were imaged in early September, at night and in field conditions, using a ground level video camera with associated optics including a heated steering mirror, wide angle lens and an electronic image intensifier. Moth flight coordinates were recorded at a rate of 50 images per second (fields) and transferred to a computer using a light pen (the only non-automated operation in the processing sequence). Software extracted ground speed vectors and, by instantaneous subtraction of wind speed data supplied by fast-response anemometers, the airspeed vectors. Accumulated density profiles of the track data revealed that moths spend most of their time at a radius of between 40 and 50 cm from the source, and rarely fly directly above it, from close range. Furthermore, the proportion of insects caught by the trap as a proportion of the number influenced by the light (and within the field of view of the camera) was very low; of 1600 individual tracks recorded over five nights, a total of only 12 were caught. Although trap efficiency is strongly dependent on trap height, time of night, season, moonlight and weather, the data analysis confirmed that moths do not exhibit straightforward positive phototaxis. In general, trajectory patterns become more complex with reduced distance from the illumination, with higher recorded values of speeds and angular velocities. However, these characteristics are further qualified by the direction of travel of the insect; the highest accelerations tended to occur when the insect was at close range, but moving away from the source. Rather than manifesting a simple positive phototaxis, the trajectories were suggestive of disorientation. Based on the data and the complex behavioural response, mathematical models were developed that described ideal density distribution in calm air and light wind speed conditions. The models did not offer a physiological hypothesis regarding the behavioural changes, but rather were tools for quantification and prediction. Since the time that the system was developed, instrumentation, computers and software have advanced considerably, allowing much more to be achieved at a small fraction of the original cost. Nevertheless, the analytical tools remain useful for automated trajectory analysis of airborne insects.  
  Address School of Electrical and Electronic Engineering, University of Manchester,Manchester M13 9PL,UK  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0007-4853 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29745349 Approved no  
  Call Number GFZ @ kyba @ Serial 1895  
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