269 research outputs found
Geographic Information from Social Network Sites
Graduate Student,
Geography
The University of KansasPlatinum Sponsors
Coca-Cola
Gold Sponsors
KU Department of Geography
KU Institute for Policy & Social Research
KU Libraries GIS and Data Services
State of Kansas Data Access and Support Center (DASC)
Wilson & Company Engineers and Architects
Silver Sponsors
Bartlett & West
Kansas Applied Remote Sensing Program
KansasView
Bronze Sponsors
Garmin
KU Biodiversity Institut
Discovering and developing primary biodiversity data from social networking sites
An ever-increasing need exists for fine-scale biodiversity occurrence records for a broad variety of research applications in biodiversity and science more generally. Even though large-scale data aggregators like GBIF serve such data in large quantities, major gaps and biases still exist, both in taxonomic coverage and in spatial coverage. To address these gaps, in this dissertation, I explored social networking sites (SNS) as a rich potential source of additional biodiversity occurrence records. In my first chapter, I explored the idea of discovering, extracting, and organizing massive numbers of biodiversity occurrence records now available on SNSs. I presented a proof-of-concept with Flickr as the SNS and Snowy Owls (Bubo scandiacus) and Monarch Butterflies (Danaus plexippus) as target species. The methods presented in this chapter can easily be used for any other SNS, region, or species group. These approaches are broadly applicable to animal and plant groups that are photographed, and that can be identified from photographs with some degree of confidence (e.g., birds, butterflies, cetaceans, orchids, dragonflies, amphibians, and plants). SNS thus offer a rich new source of biodiversity data. To understand the strengths and weaknesses of biodiversity data, we need effective tools by which to explore and visualize these data. I developed a suite of such tools in an R package called bdvis, which is described in chapter two. The package allows users to explore spatial, temporal, and taxonomic dimensions of biodiversity data sets to highlight gaps and identify strengths. In the third chapter, I explored Flickr further as a source of biodiversity data for the birds of the world, to assess the potential of augmenting the largest portal to biodiversity occurrence data, i.e., the Global Biodiversity Information Facility (GBIF). GBIF provides access to ~190 x 106 bird records, compared to ~7 x 106 that I could discover from Flickr, out of which only ~1.3 x 106 were geotagged. However, the Flickr data showed the potential to add to knowledge about birds in terms of geographic, taxonomic, and temporal dimensions, as Flickr data tended to be complementary to the GBIF-derived information. Finally, I developed a case study to investigate the quantity of records existing, and the quality of identifications by users on Flickr. I developed a detailed case study of Indian swallowtail butterflies, and implemented a crowd-sourcing platform to recruit identification expertise and apply it to butterfly photographs from the SNS. Results were encouraging, with 93% correct identities for records of this family of butterflies from across India
Distribution Mapping of Medicinal Plants: A GIS assisted approach
Graduate Student
Department of Geography
University of KansasPlatinum Sponsors
* KU Transportation Research Institute
Gold Sponsors
* KU Department of Geography
* KU Institute for Policy & Social Research
* State of Kansas Data Access and Support Center (DASC)
* KU Libraries GIS and Scholar Services
* Wilson & Company Engineers and Architects
Silver Sponsors
* Bartlett & West
* KansasView Consortium
* KU Biodiversity Institute
Bronze Sponsors
* AECOM
* Kansas Biological Survey
* C-CHANGE Program (NSF IGERT)
* KU Environmental Studies Program
* KU Department of Ecology and Evolutionary Biology
* Mid-West CAD
* National Weather Service
* Spatial Data Researc
Quantum dot nonlinearity through cavity-enhanced feedback with a charge memory
In an oxide apertured quantum dot (QD) micropillar cavity-QED system, we
found strong QD hysteresis effects and lineshape modifications even at very low
intensities corresponding to less than 0.001 intracavity photons. We attribute
this to the excitation of charges by the intracavity field; charges that get
trapped at the oxide aperture, where they screen the internal electric field
and blueshift the QD transition. This in turn strongly modulates light
absorption by cavity QED effects, eventually leading to the observed hysteresis
and lineshape modifications. The cavity also enables us to observe the QD
dynamics in real time, and all experimental data agrees well with a power-law
charging model. This effect can serve as a novel tuning mechanism for quantum
dots.Comment: 7 pages, 6 figure
Power-law persistence characterizes traveling waves in coupled circle maps with repulsive coupling
We study persistence in coupled circle maps with repulsive (inhibitory) coupling, and find that it offers an effective way to characterize the synchronous, traveling wave and spatiotemporally chaotic states of the system. In the traveling wave state, persistence decays as a power law and, in contrast to earlier observations in dynamical systems, this power-law scaling does not occur at the transition point alone, but over the entire dynamical phase (with the same exponent). We give a cellular automata model displaying the qualitative features of the traveling wave regime and provide an argument based on the theory of Motzkin numbers in combinatorics to explain the observed scaling
Learning with a Drifting Target Concept
We study the problem of learning in the presence of a drifting target
concept. Specifically, we provide bounds on the error rate at a given time,
given a learner with access to a history of independent samples labeled
according to a target concept that can change on each round. One of our main
contributions is a refinement of the best previous results for polynomial-time
algorithms for the space of linear separators under a uniform distribution. We
also provide general results for an algorithm capable of adapting to a variable
rate of drift of the target concept. Some of the results also describe an
active learning variant of this setting, and provide bounds on the number of
queries for the labels of points in the sequence sufficient to obtain the
stated bounds on the error rates
Mass Quantization of the Schwarzschild Black Hole
We examine the Wheeler-DeWitt equaton for a static, eternal Schwarzschild
black hole in Kucha\v r-Brown variables and obtain its energy eigenstates.
Consistent solutions vanish in the exterior of the Kruskal manifold and are
non-vanishing only in the interior. The system is reminiscent of a particle in
a box. States of definite parity avoid the singular geometry by vanishing at
the origin. These definite parity states admit a discrete energy spectrum,
depending on one quantum number which determines the Arnowitt-Deser-Misner
(ADM) mass of the black hole according to a relation conjectured long ago by
Bekenstein, . If attention is restricted only to these
quantized energy states, a black hole is described not only by its mass but
also by its parity. States of indefinite parity do not admit a quantized mass
spectrum.Comment: Change in eq. (13). Factors of 4 cleaned up. Refs. adde
- …