415 research outputs found
Induced Delocalization by Correlation and Interaction in the one-dimensional Anderson Model
We consider long-range correlated disorder and mutual interacting particles
according to a dipole-dipole coupling as modifications to the one-dimensional
Anderson model. Technically we rely on the (numerical) exact diagonalization of
the system's Hamilitonian. From the perspective of different localization
measures we confirm and extend the picture of the emergence of delocalized
states with increasing correlations. Beside these studies a definition for
multi-particle localization is proposed. In the case of two interacting bosons
we observe a sensitivity of localization with respect to the range of the
particle-particle interaction and insensitivity to the coupling's sign, which
should stimulate new theoretical approaches and experimental investigations
with e.g. dipolar cold quantum gases.
This revised manuscript is much more explicit compared to the initial version
of the paper. Major extensions have been applied to Sects. II and III where we
updated and added figures and we more extensively compared our results to the
literature. Furthermore, Sect. III additionally contains a phenomenological
line of reasoning that bridges from delocalization by correlation to
delocalization by interaction on the basis of the multi-particle Hamilton
matrix
Map Generation from Large Scale Incomplete and Inaccurate Data Labels
Accurately and globally mapping human infrastructure is an important and
challenging task with applications in routing, regulation compliance
monitoring, and natural disaster response management etc.. In this paper we
present progress in developing an algorithmic pipeline and distributed compute
system that automates the process of map creation using high resolution aerial
images. Unlike previous studies, most of which use datasets that are available
only in a few cities across the world, we utilizes publicly available imagery
and map data, both of which cover the contiguous United States (CONUS). We
approach the technical challenge of inaccurate and incomplete training data
adopting state-of-the-art convolutional neural network architectures such as
the U-Net and the CycleGAN to incrementally generate maps with increasingly
more accurate and more complete labels of man-made infrastructure such as roads
and houses. Since scaling the mapping task to CONUS calls for parallelization,
we then adopted an asynchronous distributed stochastic parallel gradient
descent training scheme to distribute the computational workload onto a cluster
of GPUs with nearly linear speed-up.Comment: This paper is accepted by KDD 202
On a Numerical Framework for Functional Renormalization of Quantum Statistical Physics
The subject of this thesis intends to investigate and put forward the method of
functional renormalization within the field of quantum statistical physics. Our focus is on
a (generic) truncation scheme that is suited to flexibly resolve two important mathematical
objects of physical relevance: The (inverse) propagator and the effective potential, respectively.
In the former case our effort aims at a proper resolution of the momentum dependence
which is related to the particles dispersion relation. The effective potential contains valuable
thermodynamic information on e.g. the equation of state and the system’s phase diagram.
A main achievement related to our study is the implementation of a numerical library,
libfrg, which sets up a generic framework for high performance parallel computing in
conjunction with the method of functional renormalization. By licensing it under the GNU
GPL it is tailored to foster shared development by the community of scientists with research
focus on this branch of physics
Quantification of Carbon Sequestration in Urban Forests
Vegetation, trees in particular, sequester carbon by absorbing carbon dioxide
from the atmosphere. However, the lack of efficient quantification methods of
carbon stored in trees renders it difficult to track the process. We present an
approach to estimate the carbon storage in trees based on fusing multi-spectral
aerial imagery and LiDAR data to identify tree coverage, geometric shape, and
tree species -- key attributes to carbon storage quantification. We demonstrate
that tree species information and their three-dimensional geometric shapes can
be estimated from aerial imagery in order to determine the tree's biomass.
Specifically, we estimate a total of tons of carbon sequestered in
trees for New York City's borough Manhattan
Large-Scale Geo-Data Mining for Good
The ever-increasing amount of earth observation data provides us an ample basis to sense, understand, and visualize the health of our planet. Machine learning enables us to value our home through mining massive amounts of geo-information provided by satellites and airborne measurements once curated for scalable access by a Big Geospatial Data "digital twin" platform.
My presentation intends to bridge the "AI Ethics" to the "Big Data & Global Human Behavior" session through a technical overview of remote sensor technologies demonstrating their value for applications in archaeology, urban mapping, and biomass estimation relevant to various ethical aspects. I invite you to enter a vital, interdisciplinary discussion on
a. How to leverage machine learning and remote sensing to improve the local climate in (mega)cities for the well-being of its urban population; and how to address ethical concerns related?
b. How artificial intelligence and earth observation have the capacity to help protect the Amazon rainforest led by fair principles incorporating the "perspectives of all stakeholders" such as endangered species, local farmers, archaeologists, and governments? What are the current limitations of these technologies vis-a-vis protection of human rights and ethics; and how do we overcome limitations?
c. How do we transparently implement AI-based environmental management inspired by the United Nation's Sustainable Development Goals
Geospatial Discovery Network (GeoDN): A Large-Scale Data Mining Perspective
Lightning presentation of activities in the Earth Observation Data Science department @ German Aerospace Center related to "Large-Scale Data Mining" in the context of the DLR terrabyte initiative, application of self-supervised learning to cross-data center analytics, and climate action geodata analytics to network with academia, corporate, and governmental organizations such as MIT, Oxford University, Stony Brook University, Columbia University, the New York Academy of Sciences, NASA, NOAA, ECCC, IBM Research, and Argonne National Laboratory
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The recreation resources of the Malheur National Wildlife Refuge
Heavy use of outdoor recreation areas in the United States
since World War II is endangering their quality. Demand made by a
rapidly growing population with rising personal incomes and increasing
leisure time is expected to grow 50 percent nationally and 146 percent in Oregon by 1975. In Oregon, population, incomes, and amount
of leisure time per person are all increasing more rapidly than
nationally. A large influx of out-of-state visitors accelerates the
demand.
Eighty-five percent of outdoor recreation land in the United
States and 95 percent in Oregon is owned by the Federal government.
Recreation on Federal land is in general resource-based, that is, it
depends upon some natural feature. The role of the Federal government
is therefore pre-eminent in developing sites for resource-based recreation activities.
Of the agencies involved in meeting the Federal responsibility, the possible role of the Fish and Wildlife Service is least
known. Controlling approximately four percent of outdoor recreation
land, the 300 refuges had only 13 million of the more than 500 million
visitor-days to outdoor recreation areas in 1960. Recreation visits
to refuges are increasing rapidly but apparently the quality and
quantity of the remarkable wildlife resources of the National Wildlife
Refuge System is little understood.
As the mission of the Branch of Wildlife Refuges developed, its
role involves the provision of habitat for every species of native
wildlife somewhere in the System. The refuges are widely distributed
over the nation, with the great majority, particularly those for
migratory birds, concentrated in the four great flyways. The Service
plans ultimately to include within refuge boundaries some 7.5 million
acres of the 12 million acres of wetlands needed to maintain present
waterfowl populations.
Recreation use compatible with wildlife management is permitted on the refuges but development of facilities has been slight.
Although express authorization was obtained in 1962 for such development, no funds have since been provided. The Accelerated Public Works
Program and the Job Corps Program both provide an avenue for development in some areas.
The Malheur National Wildlife Refuge, located in southeastern
Oregon, is an excellent example of the recreation potential in the
Refuge System. One of the larger refuges, its duck and geese populations number over a million during spring and fall migration. Of
Oregon's 425 bird species, 226 have been observed on the Refuge; 141
of them are listed as easily seen during one or more seasons of the year. Deer, antelope, and beaver are also easily seen.
The Refuge lies in the basin of the two playas, Malheur and
Harney Lakes, and extends for forty miles through the marshes of the
Blitzen River toward Steens Mountain, an impressive fault block with
alpine vegetation. An excellent museum exhibits indigenous species,
photographs, nests, and food plants. A display pool provides an
opportunity to observe birds at close hand. Besides wildlife observation and photography, Refuge recreation uses include fishing, water
fowl hunting, and an exceptionally high quality annual all deer archery hunt. Camping and picnicking are commonly practiced in conjunction with other recreation activities.
Recreation use of the Refuge is limited by inadequate facilities. Campsites are minimally developed and Refuge roads are impassable in wet weather. Authorization for the establishment of a Job
Corps Camp on the Refuge in June of 1965 has been obtained and it is
expected that Corps projects will serve to alleviate the deficiencies.
Development of a significant recreation resource seems assured at a
time of growing need
Feature Guided Masked Autoencoder for Self-supervised Learning in Remote Sensing
Self-supervised learning guided by masked image modelling, such as Masked
AutoEncoder (MAE), has attracted wide attention for pretraining vision
transformers in remote sensing. However, MAE tends to excessively focus on
pixel details, thereby limiting the model's capacity for semantic
understanding, in particular for noisy SAR images. In this paper, we explore
spectral and spatial remote sensing image features as improved
MAE-reconstruction targets. We first conduct a study on reconstructing various
image features, all performing comparably well or better than raw pixels. Based
on such observations, we propose Feature Guided Masked Autoencoder (FG-MAE):
reconstructing a combination of Histograms of Oriented Graidents (HOG) and
Normalized Difference Indices (NDI) for multispectral images, and
reconstructing HOG for SAR images. Experimental results on three downstream
tasks illustrate the effectiveness of FG-MAE with a particular boost for SAR
imagery. Furthermore, we demonstrate the well-inherited scalability of FG-MAE
and release a first series of pretrained vision transformers for medium
resolution SAR and multispectral images.Comment: 13 pages, 8 figure
Urban Forests for Carbon Sequestration and Heat Island Mitigation
Urban forests serve both as a carbon sequestration pool and heat island mitigation tool. Climate change will increase the frequency and severity of urban heat islands. Thus, new urban planning strategies demand our attention. Based on multimodal, remotely sensed data, we map the tree density, its carbon sequestered, and its impact on urban heat islands for Long Island, NY and Dallas, TX. Using local climate zones we investigate concepts of urban planning through optimized tree planting and adjusting building designs to mitigate urban heat islands
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