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"Armstrong, John"
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Fast Solar Image Classification Using Deep Learning and Its Importance for Automation in Solar Physics
The volume of data being collected in solar physics has exponentially increased over the past decade and with the introduction of the
Daniel K. Inouye Solar Telescope
(DKIST) we will be entering the age of petabyte solar data. Automated feature detection will be an invaluable tool for post-processing of solar images to create catalogues of data ready for researchers to use. We propose a deep learning model to accomplish this; a deep convolutional neural network is adept at feature extraction and processing images quickly. We train our network using data from
Hinode/Solar Optical Telescope
(SOT) H
α
images of a small subset of solar features with different geometries: filaments, prominences, flare ribbons, sunspots and the quiet Sun (
i.e.
the absence of any of the other four features). We achieve near perfect performance on classifying unseen images from SOT (≈ 99.9%) in 4.66 seconds. We also for the first time explore transfer learning in a solar context. Transfer learning uses pre-trained deep neural networks to help train new deep learning models
i.e.
it teaches a new model. We show that our network is robust to changes in resolution by degrading images from SOT resolution (
≈
0.33
″
at
λ
=
6563
Å) to
Solar Dynamics Observatory/Atmospheric Imaging Assembly
(SDO/AIA) resolution (
≈
1.2
″
) without a change in performance of our network. However, we also observe where the network fails to generalise to sunspots from SDO/AIA bands 1600/1700 Å due to small-scale brightenings around the sunspots and prominences in SDO/AIA 304 Å due to coronal emission.
Journal Article
A new EPMA method for fast trace element analysis in simple matrices
It is well known that trace element sensitivity in electron probe microanalysis (EPMA) is limited by intrinsic random variation in the X-ray continuum background and weak signals at low concentrations. The continuum portion of the background is produced by deceleration of the electron beam by the Coulombic field of the specimen atoms. In addition to the continuum, the background also includes interferences from secondary emission lines, \"holes\" in the continuum from secondary Bragg diffraction, non-linear curvature of the wavelength-dispersive spectrometer (WDS) continuum and other background artifacts. Typically, the background must be characterized with sufficient precision (along with the peak intensity of the emission line of interest, to obtain the net intensity for subsequent quantification), to attain reasonable accuracy for quantification of the elements of interest. Traditionally we characterize these background intensities by measuring on either side of the emission line and interpolate the intensity underneath the peak to obtain the net intensity. Instead, by applying the mean atomic number (MAN) background calibration curve method proposed in this paper for the background intensity correction, such background measurement artifacts are avoided through identification of outliers within a set of standards. We divide the analytical uncertainty of the MAN background calibration between precision errors and accuracy errors. The precision errors of the MAN background calibration are smaller than direct background measurement, if the mean atomic number of the sample matrix is precisely known. For a simple matrix and a suitable blank standard, a high-precision blank correction can offset the accuracy component of the MAN uncertainty. Use of the blank-corrected-MAN background calibration can further improve our measurement precision for trace elements compared to traditional off-peak measurements because the background determination is not limited by continuum X-ray counting statistics. For trace element mapping of a simple matrix, the background variance due to major element heterogeneity is exceedingly small and high-precision two-dimensional background correction is possible.
Journal Article
Plume-driven recratonization of deep continental lithospheric mantle
Cratons are Earth’s ancient continental land masses that remain stable for billions of years. The mantle roots of cratons are renowned as being long-lived, stable features of Earth’s continents, but there is also evidence of their disruption in the recent
1
–
6
and more distant
7
–
9
past. Despite periods of lithospheric thinning during the Proterozoic and Phanerozoic eons, the lithosphere beneath many cratons seems to always ‘heal’, returning to a thickness of 150 to 200 kilometres
10
–
12
; similar lithospheric thicknesses are thought to have existed since Archaean times
3
,
13
–
15
. Although numerous studies have focused on the mechanism for lithospheric destruction
2
,
5
,
13
,
16
–
19
, the mechanisms that recratonize the lithosphere beneath cratons and thus sustain them are not well understood. Here we study kimberlite-borne mantle xenoliths and seismology across a transect of the cratonic lithosphere of Arctic Canada, which includes a region affected by the Mackenzie plume event 1.27 billion years ago
20
. We demonstrate the important role of plume upwelling in the destruction and recratonization of roughly 200-kilometre-thick cratonic lithospheric mantle in the northern portion of the Slave craton. Using numerical modelling, we show how new, buoyant melt residues produced by the Mackenzie plume event are captured in a region of thinned lithosphere between two thick cratonic blocks. Our results identify a process by which cratons heal and return to their original lithospheric thickness after substantial disruption of their roots. This process may be widespread in the history of cratons and may contribute to how cratonic mantle becomes a patchwork of mantle peridotites of different age and origin.
Upwelling of mantle plumes is proposed as a mechanism for craton healing after substantial disruption of their roots, enabling them to return to their original lithospheric thickness.
Journal Article
The Tides of Titan
We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k 2 = 0.589 ± 0.150 and k 2 = 0.637 ± 0.224 (2σ). Such a large response to the tidal field requires that Titan's interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth.
Journal Article
الموسوعة الاقتصادية الحديثة : إدارة أعمال-تسويق-تمويل- محاسبة اقتصاد إلكتروني-اقتصاديات السياحة -إدارة القطاع الطبي-الطاقة والبيئة-الجودة الشاملة-البورصات المصارف-دراسات الجدوى-اقتصاديات العولمة-اقتصاد إسلامي-إصلاح إداري-القيادة : التسويق
هي مجموعة موسوعية ضخمة تضم ٣٢ مجلدا، من بين المجلدات الـ 32، تم تخصيص ٧ مجلدات مخصصة بالكامل لقطاع التسويق يحتوي أول مجلد في مجموعة التسويق على عنوان \"التسويق 1 – التخطيط الاستراتيجي للتسويق كل مجلد متخصص يتناول أحد أبعاد التسويق بشكل معمق.على سبيل المثال : التخطيط الاستراتيجي للتسويق : الاستراتيجيات والتخطيط طويل المدى. محتويات أخرى تشمل : سلوك المستهلك، المزيج التسويقي، التسويق الرقمي، تسويق الخدمات، بحوث التسويق، تصميم المنتجات والتسعير وغيرها من المفاهيم المعاصرة.
BOOK
Are Pain Management Questions in Patient Satisfaction Surveys Driving the Opioid Epidemic?
The United States is in the midst of a national opioid epidemic, with devastating consequences. We've seen an explosion of deaths and emergency room visits because of drug overdoses,1 increasing morbidity and mortality from hepatitis C,2 and recently in Indiana, the largest outbreak of HIV related to injection drug use in US history.3
Journal Article