7,903 research outputs found
An Improved Technique For Calibrating And Testing Power System Generator Automatic Synchronizing And Speed Matching Relays
The design of a unique special purpose instrument for calibrating and testing power system automatic synchronizing and speed matching relays is described. The unit is constructed using inexpensive integrated circuit components and provides a direct digital readout of slip frequency from 0.05 Hz to 0.50 Hz resolution and advance angle from 0 to 99.9 degrees with 0.1-degree resolution. This device eliminates the need for expensive test equipment previously required, expedites the test procedure and solves the problem of referencing against a variable bus frequency source. Copyright © 1980 by The Institute Of Electrical and Electronics Engineers, Inc
Vertical-axis rotations determined from paleomagnetism of Mesozoic and Cenozoic strata within the Bolivian Andes
Thermal demagnetization and principal component analysis allowed determination of characteristic remanent magnetization (ChRM) directions from 256 sites at 22 localities in Mesozoic and Cenozoic sedimentary strata of the Bolivian Altiplano and Eastern Cordillera. An inclination-only fold test of site-mean ChRM directions from Cenozoic units (principally the Santa LucĂa Formation) indicates optimum unfolding at 97.1% unfolding, consistent with a primary origin for the ChRM. For Mesozoic strata, optimum unfolding occurred at 89.2%, perhaps indicating secondary remagnetization at some locations. For Cenozoic units, comparison of locality-mean directions with expected paleomagnetic directions indicates vertical-axis rotations from 33° counterclockwise to 24° clockwise. Euler pole analysis of along-strike variation in crustal shortening within the Subandean and Interandean zones indicates 18° clockwise rotation south of the axis of curvature of the Bolivian Andes and 6° counterclockwise rotation northwest of the axis during the past 10 m.y. Along-strike variation of shortening within the Eastern Cordillera indicates 8° clockwise rotation south of the axis and 8° counterclockwise rotation northwest of the axis from 35 to 10 Ma. These vertical-axis rotations produced by along-strike variations in crustal shortening during development of the Bolivian fold-thrust belt agree well with observed rotations determined from paleomagnetism of Cenozoic rocks in the Eastern Cordillera and in the Subandean and Interandean zones. However, local rotations are required to account for complex rotations in the Cochabamba Basin and within the Altiplano. The curvature of the Bolivian Andes has been progressively enhanced during Cenozoic fold-thrust belt deformation
The Use of Airborne LiDAR in Assessing Coastal Erosion in the Southeastern USA
Changes in sea level along the coastal southeastern United States (U.S.) influence the dynamic coastal response. In particular, the Southeast Coastal Network (SECN) of the National Park Service (NPS) has exhibited evidence of fluctuations in sea level which caused coastal erosion. Airborne LiDAR acquired from NOAA for Fort Matanzas National Monument, Fort Pulaski National Monument, Charles Pinckney National Historic Site, and Cape Lookout National Seashore were analyzed to identify changes in both elevation and the spatial volume of unconsolidated sedimentary material in the coastal southeast over time. Areas that exhibited an increase (deposited material) or decrease (eroded material) in elevation were mapped across the study area from 2006 to 2018. Results indicate a quasi-cyclic process where unconsolidated sediment distribution and the morphodynamic equilibrium changes with time. The coastal zones are steadily oscillating between the process of erosion and deposition affecting the coastal geomorphological dynamic. The use of LiDAR for evaluating coastal sustainability and resiliency due to this environmental phenomenon is clear
Photometric redshifts and quasar probabilities from a single, data-driven generative model
We describe a technique for simultaneously classifying and estimating the
redshift of quasars. It can separate quasars from stars in arbitrary redshift
ranges, estimate full posterior distribution functions for the redshift, and
naturally incorporate flux uncertainties, missing data, and multi-wavelength
photometry. We build models of quasars in flux-redshift space by applying the
extreme deconvolution technique to estimate the underlying density. By
integrating this density over redshift one can obtain quasar flux-densities in
different redshift ranges. This approach allows for efficient, consistent, and
fast classification and photometric redshift estimation. This is achieved by
combining the speed obtained by choosing simple analytical forms as the basis
of our density model with the flexibility of non-parametric models through the
use of many simple components with many parameters. We show that this technique
is competitive with the best photometric quasar classification
techniques---which are limited to fixed, broad redshift ranges and high
signal-to-noise ratio data---and with the best photometric redshift techniques
when applied to broadband optical data. We demonstrate that the inclusion of UV
and NIR data significantly improves photometric quasar--star separation and
essentially resolves all of the redshift degeneracies for quasars inherent to
the ugriz filter system, even when included data have a low signal-to-noise
ratio. For quasars spectroscopically confirmed by the SDSS 84 and 97 percent of
the objects with GALEX UV and UKIDSS NIR data have photometric redshifts within
0.1 and 0.3, respectively, of the spectroscopic redshift; this amounts to about
a factor of three improvement over ugriz-only photometric redshifts. Our code
to calculate quasar probabilities and redshift probability distributions is
publicly available
Real-time biochemical assay telemetering system
The present invention is an apparatus and a method of detecting a chemical released by perspiration, typically through sweat and broadcasting the detection to a receiver. The chemical may be a drug of abuse. The device which is attached to the skin of a subject contains labeled antibodies or label containing microspheres attached to antibodies. The labeled antibodies are bound to solid phase drug via antigen-antibody interaction. These labeled antibodies are displaced from the solid phase support to which they are bound by free drug molecules in the perspiration. These labeled antibodies then migrate through a spacer layer and are trapped by a layer containing a suitable selective binding material. The label is illuminated or excited by a light source and detected by a photodetector. The signal can be recorded, or transmitted to a remote radio monitor
Evolution and Diffusion of the Michigan State University Tradition of Organizational Communication Network Research
This article documents the 30-year history of communication network research at Michigan State University (M.S.U.), providing a case study of the evolution and diffusion of an academic innovation. Three past and continuing issues for network scholars are identified: a lack of professional reward for developing user-friendly computer programs, unresolved methodological problems, and a need for better theoretical and conceptual frameworks. The narrative also illustrates the difficulty communication as a discipline has in impacting broader intellectual traditions. The story begins with the first doctoral dissertation (Schwartz, 1968) and the first network analysis software program in 1970 (Richards’ Negopy), continuing to the last dissertation (Susskind, 1996), and ending in 1998 when J. David Johnson left the M.S.U. faculty. Other major players in the M.S.U. network tradition included David K. Berio, Eugene Jacobson, Everett M. Rogers, Vincent Farace, Peter Monge, and Erwin Bettinghaus. Ironically, Schwartz and Susskind met in 1998 while Schwartz was preparing to retire from Cornell University and Susskind was starting as an Assistant Professor in a different department, thus providing closure to the M.S.U. network
A Simple Likelihood Method for Quasar Target Selection
We present a new method for quasar target selection using photometric fluxes
and a Bayesian probabilistic approach. For our purposes we target quasars using
Sloan Digital Sky Survey (SDSS) photometry to a magnitude limit of g=22. The
efficiency and completeness of this technique is measured using the Baryon
Oscillation Spectroscopic Survey (BOSS) data, taken in 2010. This technique was
used for the uniformly selected (CORE) sample of targets in BOSS year one
spectroscopy to be realized in the 9th SDSS data release. When targeting at a
density of 40 objects per sq-deg (the BOSS quasar targeting density) the
efficiency of this technique in recovering z>2.2 quasars is 40%. The
completeness compared to all quasars identified in BOSS data is 65%. This paper
also describes possible extensions and improvements for this techniqueComment: Updated to accepted version for publication in the Astrophysical
Journal. 10 pages, 10 figures, 3 table
Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
We present the SDSS-XDQSO quasar targeting catalog for efficient flux-based
quasar target selection down to the faint limit of the Sloan Digital Sky Survey
(SDSS) catalog, even at medium redshifts (2.5 <~ z <~ 3) where the stellar
contamination is significant. We build models of the distributions of stars and
quasars in flux space down to the flux limit by applying the
extreme-deconvolution method to estimate the underlying density. We convolve
this density with the flux uncertainties when evaluating the probability that
an object is a quasar. This approach results in a targeting algorithm that is
more principled, more efficient, and faster than other similar methods. We
apply the algorithm to derive low-redshift (z < 2.2), medium-redshift (2.2 <= z
3.5) quasar probabilities for all 160,904,060
point sources with dereddened i-band magnitude between 17.75 and 22.45 mag in
the 14,555 deg^2 of imaging from SDSS Data Release 8. The catalog can be used
to define a uniformly selected and efficient low- or medium-redshift quasar
survey, such as that needed for the SDSS-III's Baryon Oscillation Spectroscopic
Survey project. We show that the XDQSO technique performs as well as the
current best photometric quasar-selection technique at low redshift, and
outperforms all other flux-based methods for selecting the medium-redshift
quasars of our primary interest. We make code to reproduce the XDQSO quasar
target selection publicly available
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