The FHD/ε\boldsymbol{\varepsilon}ppsilon Epoch of Reionization Power Spectrum Pipeline

Epoch of Reionization data analysis requires unprecedented levels of accuracy in radio interferometer pipelines. We have developed an imaging power spectrum analysis to meet these requirements and generate robust 21 cm EoR measurements. In this work, we build a signal path framework to mathematically describe each step in the analysis, from data reduction in the FHD package to power spectrum generation in the $\varepsilon$ppsilon package. In particular, we focus on the distinguishing characteristics of FHD/$\varepsilon$ppsilon: highly accurate spectral calibration, extensive data verification products, and end-to-end error propagation. We present our key data analysis products in detail to facilitate understanding of the prominent systematics in image-based power spectrum analyses. As a verification to our analysis, we also highlight a full-pipeline analysis simulation to demonstrate signal preservation and lack of signal loss. This careful treatment ensures that the FHD/$\varepsilon$ppsilon power spectrum pipeline can reduce radio interferometric data to produce credible 21 cm EoR measurements.Comment: 21 pages, 10 figures, accepted by PAS

Automatic 3D model construction for turn-table sequences

As virtual worlds demand ever more realistic 3D models, attention is being focussed on systems that can acquire graphical models from real objects. This paper describes a system which, given a sequence of images of an object rotating about a single axis, generates a textured 3D model fully automatically. In contrast to previous approaches, the technique described here requires no prior information about the cameras or scene, and does not require that the turntable angles be known (or even constant through the sequence). From an analysis of the projective geometry of the situation, it is shown that the rotation angles may be determined unambiguously, and that camera calibration, camera positions and 3D structure may be determined to within a two parameter family. An algorithm has been implemented to compute this reconstruction fully automatically. The two parameter reconstruction ambiguity may be removed by specifying, for example, camera aspect ratio and parallel scene lines. Examples are presented on four turn-table sequences

Deep Learning for Vanishing Point Detection Using an Inverse Gnomonic Projection

We present a novel approach for vanishing point detection from uncalibrated monocular images. In contrast to state-of-the-art, we make no a priori assumptions about the observed scene. Our method is based on a convolutional neural network (CNN) which does not use natural images, but a Gaussian sphere representation arising from an inverse gnomonic projection of lines detected in an image. This allows us to rely on synthetic data for training, eliminating the need for labelled images. Our method achieves competitive performance on three horizon estimation benchmark datasets. We further highlight some additional use cases for which our vanishing point detection algorithm can be used.Comment: Accepted for publication at German Conference on Pattern Recognition (GCPR) 2017. This research was supported by German Research Foundation DFG within Priority Research Programme 1894 "Volunteered Geographic Information: Interpretation, Visualisation and Social Computing

Wind-induced, cross-frontal exchange on Georges Bank : a mechanism for early summer on-bank biological particle transport

Author Posting. © American Geophysical Union, 2003. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 108, C11 (2003): 8011, doi:10.1029/2002JC001358.Water exchange across the tidal-mixing front on the southern flank of Georges Bank (GB) is examined using a two-dimensional (2D) primitive equation ocean model. The model domain features a cross-frontal transect including a June 1999 hydrographic (CTD)/ADCP study made as part of the U.S. GLOBEC Northwest Atlantic/Georges Bank program. The model was initialized with temperature and salinity fields taken on the 15 June 1999 CTD section and run prognostically with tidal forcing, measured winds, and representative surface heat flux. The results show that fluctuations of wind plus tidal mixing can play the following essential role in the short-term transport of water and particles from the stratified region to the mixed region on GB in early summer, when stratification is just developing with a weak thermocline at a depth of about 10 m. First, a passing weather front drives a wind-induced on-bank Ekman transport of the upper part of the water column at the tidal-mixing front and associated particles in the surface mixed layer. Then, when the wind relaxes or changes direction, the water in the on-bank extension of the front (above the thermocline) mixes quickly through enhanced tidal motion in shallower depths of water. As a result, particles that are advected along the extended front stay in the previously well-mixed region of the bank. Surface heating tends to increase the strength of the thermocline and reduce the thickness of the surface mixed layer. This in turn accelerates the on-bank movement of the front under an easterly wind favorable for Ekman transport and thus enhances the on-bank, cross-frontal transport of particles. Since the wind-induced, cross-frontal on-bank transport of water can occur episodically during passages of meteorological fronts, these could produce a larger net cross-frontal flux than that produced by just tidal forcing on equivalent timescales. Therefore wind-induced processes can be important in the on-bank cross-frontal flux of copepods and other zooplankton species that exhibit shallow maxima in their vertical distributions over the southern flank of GB in early summer.This research was supported by the U.S. GLOBEC Northwest Atlantic/Georges Bank program through NOAA grants NA56RG0487, NA960P003, and NA960P005 to C. Chen, NOAA support to R. Schlitz, G. R. Lough, K. Smith, and J. Manning, and NSF grants OCE 96-32357, OCE 98-06379, and OCE 02-27679 to R. Beardsley

A Spectroscopic Study of Field and Runaway OB Stars

Identifying binaries among runaway O- and B-type stars offers valuable insight into the evolution of open clusters and close binary stars. Here we present a spectroscopic investigation of 12 known or suspected binaries among field and runaway OB stars. We find new orbital solutions for five single-lined spectroscopic binaries (HD 1976, HD 14633, HD 15137, HD 37737, and HD 52533), and we classify two stars thought to be binaries (HD 30614 and HD 188001) as single stars. In addition, we reinvestigate their runaway status using our new radial velocity data with the UCAC2 proper motion catalogs. Seven stars in our study appear to have been ejected from their birthplaces, and at least three of these runaways are spectroscopic binaries and are of great interest for future study.Comment: 21 pages, 1 figure, 7 tables; Accepted to Ap

Cruise report YALOC '69 : synopsis of the cruise of R/V Yaquina in the eastern equatorial Pacific Ocean from 2 January to 26 April, 1969

A multi-disciplinary oceanographic cruise - YALOC '69 - was carried out by staff of the Department of Oceanography, Oregon State University aboard the R/V YAQUINA. This report describes the observational programs undertaken. YALOC '69 was motivated by a desire to study the geology, geophysics and physical oceanography of the Panama Basin. Near bottom chemical gradients were investigated at a number of stations along the track line. Hydrographic and optical measurements were also made enroute to the area to obtain data on the geographical distribution of optical properties. The cruise consisted of seven legs extending from Newport, Oregon to Talara, Peru and return, with the three principal working legs in the Panama Basin. Station locations are shown in Figures 1 and 2. The cruise began January 2, 1969 and was completed April 26, 1969. Exceptionally fine weather and following winds produced ideal working conditions. As a result, about 120% of the planned objectives were achieved. The scientific personnel included four faculty members, nine students, and five technicians from Oregon State University. The scientific complement also included visiting scientists from: U. S. Naval Postgraduate School, Monterey, California; University of Copenhagen, Denmark, and the Ecuadorian Navy. The ship was supported during this period by ONR Grant 1286(10) and NSF Grant GA 1252. Research support is listed under the individual discussions which follow

Ocean variability contributing to basal melt rate near the ice front of Ross Ice Shelf, Antarctica

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 4214–4233, doi:10.1002/2014JC009792.Basal melting of ice shelves is an important, but poorly understood, cause of Antarctic ice sheet mass loss and freshwater production. We use data from two moorings deployed through Ross Ice Shelf, ∼6 and ∼16 km south of the ice front east of Ross Island, and numerical models to show how the basal melting rate near the ice front depends on sub-ice-shelf ocean variability. The moorings measured water velocity, conductivity, and temperature for ∼2 months starting in late November 2010. About half of the current velocity variance was due to tides, predominantly diurnal components, with the remainder due to subtidal oscillations with periods of a few days. Subtidal variability was dominated by barotropic currents that were large until mid-December and significantly reduced afterward. Subtidal currents were correlated between moorings but uncorrelated with local winds, suggesting the presence of waves or eddies that may be associated with the abrupt change in water column thickness and strong hydrographic gradients at the ice front. Estimated melt rate was ∼1.2 ± 0.5 m a−1 at each site during the deployment period, consistent with measured trends in ice surface elevation from GPS time series. The models predicted similar annual-averaged melt rates with a strong annual cycle related to seasonal provision of warm water to the ice base. These results show that accurately modeling the high spatial and temporal ocean variability close to the ice-shelf front is critical to predicting time-dependent and mean values of meltwater production and ice-shelf thinning.The Woods Hole Oceanographic Institution (WHOI) participation in the ANDRILL Coulman High Program was supported by the National Science Foundation Office of Polar Programs (NSF ANT-0839108) through a subcontract from the University of Nebraska, Lincoln (UNL 25-0550-0004-004). I. Arzeno was supported as a 2011 WHOI Summer Student Fellow through the NSF Research Experiences for Undergraduates program (OCE- 0649139). L. Padman and S. Springer were supported by NASA grant NNX10AG19G to Earth & Space Research (ESR). M. Williams and C. Stewart were supported by the New Zealand National Institute of Water and Atmosphere (NIWA) core funding under the National Climate Centre, and the Ministry of Business, Innovation, and Employment (Contract CO5X1001).2015-01-0