28,749 research outputs found
GEE Training Manual on Use of Earth Observation data and Google Earth Engine monitoring and early warning of floods and droughts in Zambia
This training manual supported participants in learning the pre-processing tool to provide the user with enhanced time-series processing capabilities and access to various open-source satellite data, learning basic scripts in Google Earth Engine for activities related to floods and drought in showcasing the application of water resource management. Specifically, the experts will give more focus to Google’s Earth Engine platform to showcase large- and small-scale scientific analysis and visualization of geospatial datasets. The codes and step by step procedure are given in the manual
Exact -dimensional cosmological-type solutions in gravitational model with Yang-Mills field, Gauss-Bonnet term and -term
We consider -dimensional gravitational model with Yang-Mills
field, Gauss-Bonnet term and -term. We study so-called cosmological
type solutions defined on product manifold , where
is Calabi-Yau manifold. By putting the gauge field 1-form to be
coinciding with 1-form spin connection on , we obtain exact cosmological
solutions with exponential dependence of scale factors (upon -variable),
governed by two non-coinciding Hubble-like parameters: , , obeying . We also present static analogs of these cosmological solutions
(for , and ). The islands of stability
for both classes of solutions are outlined.Comment: 17 pages, 3 figures, LaTex, Revised version: 3 paragraphs are added
into Introduction, new references are included and few references
(self-citations) are omitte
Examples of works to practice staccato technique in clarinet instrument
Klarnetin staccato tekniğini güçlendirme aşamaları eser çalışmalarıyla uygulanmıştır. Staccato
geçişlerini hızlandıracak ritim ve nüans çalışmalarına yer verilmiştir. Çalışmanın en önemli amacı
sadece staccato çalışması değil parmak-dilin eş zamanlı uyumunun hassasiyeti üzerinde de
durulmasıdır. Staccato çalışmalarını daha verimli hale getirmek için eser çalışmasının içinde etüt
çalışmasına da yer verilmiştir. Çalışmaların üzerinde titizlikle durulması staccato çalışmasının ilham
verici etkisi ile müzikal kimliğe yeni bir boyut kazandırmıştır. Sekiz özgün eser çalışmasının her
aşaması anlatılmıştır. Her aşamanın bir sonraki performans ve tekniği güçlendirmesi esas alınmıştır.
Bu çalışmada staccato tekniğinin hangi alanlarda kullanıldığı, nasıl sonuçlar elde edildiği bilgisine
yer verilmiştir. Notaların parmak ve dil uyumu ile nasıl şekilleneceği ve nasıl bir çalışma disiplini
içinde gerçekleşeceği planlanmıştır. Kamış-nota-diyafram-parmak-dil-nüans ve disiplin
kavramlarının staccato tekniğinde ayrılmaz bir bütün olduğu saptanmıştır. Araştırmada literatür
taraması yapılarak staccato ile ilgili çalışmalar taranmıştır. Tarama sonucunda klarnet tekniğin de
kullanılan staccato eser çalışmasının az olduğu tespit edilmiştir. Metot taramasında da etüt
çalışmasının daha çok olduğu saptanmıştır. Böylelikle klarnetin staccato tekniğini hızlandırma ve
güçlendirme çalışmaları sunulmuştur. Staccato etüt çalışmaları yapılırken, araya eser çalışmasının
girmesi beyni rahatlattığı ve istekliliği daha arttırdığı gözlemlenmiştir. Staccato çalışmasını yaparken
doğru bir kamış seçimi üzerinde de durulmuştur. Staccato tekniğini doğru çalışmak için doğru bir
kamışın dil hızını arttırdığı saptanmıştır. Doğru bir kamış seçimi kamıştan rahat ses çıkmasına
bağlıdır. Kamış, dil atma gücünü vermiyorsa daha doğru bir kamış seçiminin yapılması gerekliliği
vurgulanmıştır. Staccato çalışmalarında baştan sona bir eseri yorumlamak zor olabilir. Bu açıdan
çalışma, verilen müzikal nüanslara uymanın, dil atış performansını rahatlattığını ortaya koymuştur.
Gelecek nesillere edinilen bilgi ve birikimlerin aktarılması ve geliştirici olması teşvik edilmiştir.
Çıkacak eserlerin nasıl çözüleceği, staccato tekniğinin nasıl üstesinden gelinebileceği anlatılmıştır.
Staccato tekniğinin daha kısa sürede çözüme kavuşturulması amaç edinilmiştir. Parmakların
yerlerini öğrettiğimiz kadar belleğimize de çalışmaların kaydedilmesi önemlidir. Gösterilen azmin ve
sabrın sonucu olarak ortaya çıkan yapıt başarıyı daha da yukarı seviyelere çıkaracaktır
Entanglement Islands from Hilbert Space Reduction
In this paper we try to understand the \textit{Island formula} from a purely
quantum information perspective. We propose that the island phase is a property
of the quantum state and the Hilbert space where the state is embedded in. More
explicitly we show that, in a quantum system when the state of a subset is
totally encoded in the state of another subset, the Hilbert space of the system
will reduce, and the way we compute the reduced density matrix and related
entropy quantities will also change essentially. Such reductions of the Hilbert
space result in a new island formula in quantum systems, which we conjecture to
be the same island formula in gravity recently proposed to rescue the unitarity
in the process of black hole evaporation. In this context, we give a simple
resolution to the Mathur/AMPS paradox. Furthermore, we propose a
non-gravitational field theory configuration where entanglement islands emerge,
give a description for the entanglement structure of the island phase and
propose how to realize the island phase in the lab.Comment: 28pages. Comments are very welcome; V2 references updated, minor
revision; V3, footnote 5 adde
Diverging black hole entropy from quantum infrared non-localities
Local higher-derivative corrections to the Einstein-Hilbert action yield
sub-leading corrections to the Bekenstein-Hawking area law. Here we show that
if the quantum effective action comprises a certain class of infrared
non-localities, the entropy of large black holes generally diverges to either
positive or negative infinity. In such theories, large spherically symmetric
black holes would be either highly chaotic or thermodynamically impossible,
respectively. In turn, this puts strong constraints on the Laurent expansion of
the form factors in the effective action.Comment: 5 pages + appendi
3d mirror symmetry of braided tensor categories
We study the braided tensor structure of line operators in the topological A
and B twists of abelian 3d gauge theories, as accessed via
boundary vertex operator algebras (VOA's). We focus exclusively on abelian
theories. We first find a non-perturbative completion of boundary VOA's in the
B twist, which start out as certain affine Lie superalebras; and we construct
free-field realizations of both A and B-twist VOA's, finding an interesting
interplay with the symmetry fractionalization group of bulk theories. We use
the free-field realizations to establish an isomorphism between A and B VOA's
related by 3d mirror symmetry. Turning to line operators, we extend previous
physical classifications of line operators to include new monodromy defects and
bound states. We also outline a mechanism by which continuous global symmetries
in a physical theory are promoted to higher symmetries in a topological twist
-- in our case, these are infinite one-form symmetries, related to boundary
spectral flow, which structure the categories of lines and control abelian
gauging. Finally, we establish the existence of braided tensor structure on
categories of line operators, viewed as non-semisimple categories of modules
for boundary VOA's. In the A twist, we obtain the categories by extending
modules of symplectic boson VOA's, corresponding to gauging free
hypermultiplets; in the B twist, we instead extend Kazhdan-Lusztig categories
for affine Lie superalgebras. We prove braided tensor equivalences among the
categories of 3d-mirror theories. All results on VOA's and their module
categories are mathematically rigorous; they rely strongly on recently
developed techniques to access non-semisimple extensions.Comment: 158 pages, comments welcome
and Freeze-Out Distributions and Global Polarizations in Au+Au Collisions
The gold--gold collisions at and GeV are simulated
within the PHSD transport model. In each collision event, the spectator
nucleons are separated and the fluidization procedure for the participants is
performed. The local velocities are determined in the Landau frame and the
kinematic and thermal vorticity fields are evaluated. We analyze the
thermodynamic properties of the cells where s and
s were born or had their last interaction. Such cells
contribute to the formation of the observed global polarization of hyperons
induced by the thermal vorticity of the medium. The
polarization signal is found to be mainly determined by hot, dense, and highly
vortical cells at the earlier stage of the collision, whereas the
polarization signal is accumulated over the longer time and includes cells with
lower vorticity. The calculated global polarizations for both s and
s agree well with the experimental finding by the STAR
collaboration at energy GeV. For collisions at
GeV, we can reproduce the STAR data for hyperons,
but significantly underpredict the observed global polarization of
. Furthermore, we consider the centrality dependence of the
hyperon polarization in collisions at 7.7GeV. It increases with an increase of
centrality, reaches a maximum at 65--75%, and then starts decreasing rapidly
for peripheral collisions.Comment: 12 pages, 6 figure
Deep Unrestricted Document Image Rectification
In recent years, tremendous efforts have been made on document image
rectification, but existing advanced algorithms are limited to processing
restricted document images, i.e., the input images must incorporate a complete
document. Once the captured image merely involves a local text region, its
rectification quality is degraded and unsatisfactory. Our previously proposed
DocTr, a transformer-assisted network for document image rectification, also
suffers from this limitation. In this work, we present DocTr++, a novel unified
framework for document image rectification, without any restrictions on the
input distorted images. Our major technical improvements can be concluded in
three aspects. Firstly, we upgrade the original architecture by adopting a
hierarchical encoder-decoder structure for multi-scale representation
extraction and parsing. Secondly, we reformulate the pixel-wise mapping
relationship between the unrestricted distorted document images and the
distortion-free counterparts. The obtained data is used to train our DocTr++
for unrestricted document image rectification. Thirdly, we contribute a
real-world test set and metrics applicable for evaluating the rectification
quality. To our best knowledge, this is the first learning-based method for the
rectification of unrestricted document images. Extensive experiments are
conducted, and the results demonstrate the effectiveness and superiority of our
method. We hope our DocTr++ will serve as a strong baseline for generic
document image rectification, prompting the further advancement and application
of learning-based algorithms. The source code and the proposed dataset are
publicly available at https://github.com/fh2019ustc/DocTr-Plus
Interview with Wolfgang Knauss
An oral history in four sessions (September 2019–January 2020) with Wolfgang Knauss, von Kármán Professor of Aeronautics and Applied Mechanics, Emeritus. Born in Germany in 1933, he speaks about his early life and experiences under the Nazi regime, his teenage years in Siegen and Heidelberg during the Allied occupation, and his move to Pasadena, California, in 1954 under the sponsorship of a local minister and his family. He enrolled in Caltech as an undergraduate in 1957, commencing a more than half-century affiliation with the Institute and GALCIT (today the Graduate Aerospace Laboratories of Caltech). He recalls the roots of his interest in aeronautics, his PhD solid mechanics studies with his advisor, M. Williams, and the GALCIT environment in the late 1950s and 1960s at the dawn of the Space Age, including the impact of Sputnik and classes with NASA astronauts. He discusses his experimental and theoretical work on materials deformation, dynamic fracture, and crack propagation, including his solid-propellant fuels research for NASA and the US Army, wide-ranging programs with the US Navy, and his pioneering micromechanics investigations and work on the time-dependent fracture of polymers in the 1990s.
He offers his perspective on GALCIT’s academic culture, its solid mechanics and fluid mechanics programs, and its evolving administrative directions over the course of five decades, as well as its impact and reputation both within and beyond Caltech. He describes his work with Caltech’s undergraduate admissions committee and his scientific collaborations with numerous graduate students and postdocs and shares his recollections of GALCIT and other Caltech colleagues, including C. Babcock, D. Coles, R.P. Feynman, Y.C. Fung, G. Neugebauer, G. Housner, D. Hudson, H. Liepmann, A. Klein, G. Ravichandran, A. Rosakis, A. Roshko, and E. Sechler.
Six appendices contributed by Dr. Knauss, offering further insight into his life and career, also form part of this oral history and are cross-referenced in the main text
The temporality of rhetoric: the spatialization of time in modern criticism
Every conception of criticism conceals a notion of time which informs the manner in which the critic conceives of history, representation and criticism itself. This thesis reveals the philosophies of time inherent in certain key modern critical concepts: allegory, irony and the sublime. Each concept opens a breach in time, a disruption of chronology. In each case this gap or aporia is emphatically closed, elided or denied. Taking the philosophy of time elaborated by Giorgio Agamben as an introductory proposition, my argument turns in Chapter One to the allegorical temporality which Walter Benjamin sees as the time of photography. The second chapter examines the aesthetics of the sublime as melancholic or mournful untimeliness. In Chapter Three, Paul de Man's conception of irony provides an exemplary instance of the denial of this troubling temporal predicament. In opposition to the foreclosure of the disturbing temporalities of criticism, history and representation, the thesis proposes a fundamental rethinking of the philosophy of time as it relates to these categories of reflection. In a reading of an inaugural meditation on the nature of time, and in examining certain key contemporary philosophical and critical texts, I argue for a critical attendance to that which eludes those modes of thought that attempt to map time as a recognizable and essentially spatial field. The Confessions of Augustine provide, in the fourth chapter, a model for thinking through the problems set up earlier: Augustine affords us, precisely, a means of conceiving of the gap or the interim. In the final chapter, this concept is developed with reference to the criticism of Arnold and Eliot, the fiction of Virginia Woolf and the philosophy of cinema derived from Deleuze and Lyotard. In conclusion, the philosophical implications of the thesis are placed in relation to a conception of the untimeliness of death
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