1,162 research outputs found
Eye movement control and top-down scanpath vision as a design metaphor for robotic vision and control
The topics covered include the following: eye movement control; higher level eye movement control and Scanpath Theory; top-down robotic vision; and overall robotic control scheme
Autonomous Image Processing Algorithms Locate Region-of-Interests: The Mars Rover Application
In this report, we demonstrate that bottom-up IPA's, image-processing algorithms, can perform a new visual task to select and locate Regions-Of-Interests (ROIs). This task has been defined on the basis of a theory of top-down human vision, the scanpath theory. Further, using measures, Sp and Ss, the similarity of location and ordering, respectively, developed over the years in studying human perception and the active looking role of eye movements, we could quantify the efficient and efficacious manner that IPAs can imitate human vision in located ROIS. The means to quantitatively evaluate IPA performance has been an important part of our study. In fact, these measures were essential in choosing from the initial wide variety of IPAS, that particular one that best serves for a type of picture and for a required task. It should be emphasized that the selection of efficient IPAs has depended upon their correlation with actual human chosen ROIs for the same type of picture and for the same required task accomplishment
The Effects of Pictorial Realism, Delay of Visual Feedback, and Observer Interactivity on the Subjective Sense of Presence
Two experiments examined the effects of pictorial realism, observer interactivity, and delay of visual feedback on the sense of presence. Subjects were presented pairs of virtual enviornments (a simulated driving task) that differed in one or more ways from each other. After subjects had completed the second member of each pair they reported which of the two had produced the greater amount of presence and indicated the size of this difference by means of a 1-100 scale. As predicted, realism and interactivity increased presence while delay of visual feedback diminished it. According to subjects\u27 verbal responses to a postexperiment interview, pictorial realism was the least influential of the three variables examined. Further, although some subjects reported an increase in the sense of presence over the course of the experiment, most said it reamined unchanged or became weaker
A remarkably high fraction of strong Ly_alpha emitters amongst luminous redshift 6.0<z<6.5 Lyman break galaxies in the UKIDSS Ultra-Deep Survey
We present spectroscopic confirmation of ten highly luminous (L >= 2L*) Lyman
alpha emitters in the redshift range 6.01<z<6.49 (nine galaxies and one AGN),
initially drawn from a sample of fourteen z_phot >= 6 Lyman break galaxies
(LBGs) selected from an area of 0.25 square degrees within the UKIDSS
Ultra-deep Survey (UDS). Overall, our high rate of spectroscopic confirmation
(>= 71%) and low rate of contamination provides a strong vindication of the
photometric redshift analysis used to define the original sample. By
considering star-formation rate estimates based on the Ly_alpha and UV
continuum luminosity we conclude that our sample is consistent with a Ly_alpha
escape fraction of ~25%. Moreover, after careful consideration of the potential
uncertainties and biases, we find that 40%-50% of our sample of L >= 2L*
galaxies at 6.0<z<6.5 display strong Ly_alpha emission (rest-frame equivalent
width >= 25 Angs), a fraction which is a factor of ~2 higher than previously
reported for L <= L* galaxies at z~6. Our results suggest that, as the epoch of
reionization is approached, it is plausible that the Ly_alpha emitter fraction
amongst luminous (L >=2 L*) LBGs shows a similarly sharp increase to that
observed in their lower-luminosity (L <= L*) counterparts.Comment: accepted by MNRAS, 13 pages, 7 figure
Privatization and State Capacity in Postcommunist Society
Economists have used cross-national regression analysis to argue that postcommunist economic failure is the result of inadequate adherence liberal economic policies. Sociologists have relied on case study data to show that postcommunist economic failure is the outcome of too close adherence to liberal policy recommendations, which has led to an erosion of state effectiveness, and thus produced poor economic performance. The present paper advances a version of this statist theory based on a quantitative analysis of mass privatization programs in the postcommunist world. We argue that rapid large-scale privatization creates severe supply and demand shocks for enterprises, thereby inducing firm failure. The resulting erosion of tax revenues leads to a fiscal crisis for the state, and severely weakens its capacity and bureaucratic character. This, in turn, reacts back on the enterprise sector, as the state can no longer support the institutions necessary for the effective functioning of a modern economy, thus resulting in deindustrialization. Using cross-national regression techniques we find that the implementation of mass privatization programs negatively impacts measures of economic growth, state capacity and the security of property rights.http://deepblue.lib.umich.edu/bitstream/2027.42/40192/3/wp806.pd
Site testing for submillimetre astronomy at Dome C, Antarctica
Over the past few years a major effort has been put into the exploration of
potential sites for the deployment of submillimetre astronomical facilities.
Amongst the most important sites are Dome C and Dome A on the Antarctic
Plateau, and the Chajnantor area in Chile. In this context, we report on
measurements of the sky opacity at 200 um over a period of three years at the
French-Italian station, Concordia, at Dome C, Antarctica. We also present some
solutions to the challenges of operating in the harsh polar environ- ment. Dome
C offers exceptional conditions in terms of absolute atmospheric transmission
and stability for submillimetre astron- omy. Over the austral winter the PWV
exhibits long periods during which it is stable and at a very low level (0.1 to
0.3 mm). Higher values (0.2 to 0.8 mm) of PWV are observed during the short
summer period. Based on observations over three years, a transmission of around
50% at 350 um is achieved for 75% of the time. The 200-um window opens with a
typical transmission of 10% to 15% for 25% of the time. Dome C is one of the
best accessible sites on Earth for submillimetre astronomy. Observations at 350
or 450 {\mu}m are possible all year round, and the 200-um window opens long
enough and with a sufficient transparency to be useful. Although the polar
environment severely constrains hardware design, a permanent observatory with
appropriate technical capabilities is feasible. Because of the very good
astronomical conditions, high angular resolution and time series (multi-year)
observations at Dome C with a medium size single dish telescope would enable
unique studies to be conducted, some of which are not otherwise feasible even
from space
THE ROLE OF INTERDEPENDENCE IN THE MICRO-FOUNDATIONS OF ORGANIZATION DESIGN: TASK, GOAL, AND KNOWLEDGE INTERDEPENDENCE
Interdependence is a core concept in organization design, yet one that has remained consistently understudied. Current notions of interdependence remain rooted in seminal works, produced at a time when managers’ near-perfect understanding of the task at hand drove the organization design process. In this context, task interdependence was rightly assumed to be exogenously determined by characteristics of the work and the technology. We no longer live in that world, yet our view of interdependence has remained exceedingly task-centric and our treatment of interdependence overly deterministic. As organizations face increasingly unpredictable workstreams and workers co-design the organization alongside managers, our field requires a more comprehensive toolbox that incorporates aspects of agent-based interdependence. In this paper, we synthesize research in organization design, organizational behavior, and other related literatures to examine three types of interdependence that characterize organizations’ workflows: task, goal, and knowledge interdependence. We offer clear definitions for each construct, analyze how each arises endogenously in the design process, explore their interrelations, and pose questions to guide future research
Science Programs for a 2 m-class Telescope at Dome C, Antarctica: PILOT, the Pathfinder for an International Large Optical Telescope
The cold, dry and stable air above the summits of the Antarctic plateau
provides the best ground-based observing conditions from optical to sub-mm
wavelengths to be found on the Earth. PILOT is a proposed 2 m telescope, to be
built at Dome C in Antarctica, able to exploit these conditions for conducting
astronomy at optical and infrared wavelengths. While PILOT is intended as a
pathfinder towards the construction of future grand-design facilities, it will
also be able to undertake a range of fundamental science investigations in its
own right. This paper provides the performance specifications for PILOT,
including its instrumentation. It then describes the kinds of science projects
that it could best conduct. These range from planetary science to the search
for other solar systems, from star formation within the Galaxy to the star
formation history of the Universe, and from gravitational lensing caused by
exo-planets to that produced by the cosmic web of dark matter. PILOT would be
particularly powerful for wide-field imaging at infrared wavelengths, achieving
near-diffraction limited performance with simple tip-tilt wavefront correction.
PILOT would also be capable of near-diffraction limited performance in the
optical wavebands, as well be able to open new wavebands for regular ground
based observation; in the mid-IR from 17 to 40 microns and in the sub-mm at 200
microns.Comment: 74 pages, 14 figures, PASA, in pres
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Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure
This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve sigma(sum m_nu) = 16 meV and sigma(N_eff) = 0.020. Such a mass measurement will produce a high significance detection of non-zero sum m_nu, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics --- the origin of mass. This precise a measurement of N_eff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that N_eff = 3.046.Astronom
Analysis of DNA double-strand break response and chromatin structure in mitosis using laser microirradiation
In this study the femtosecond near-IR and nanosecond green lasers are used to induce alterations in mitotic chromosomes. The subsequent double-strand break responses are studied. We show that both lasers are capable of creating comparable chromosomal alterations and that a phase paling observed within 1–2 s of laser exposure is associated with an alteration of chromatin as confirmed by serial section electron microscopy, DAPI, γH2AX and phospho-H3 staining. Additionally, the accumulation of dark material observed using phase contrast light microscopy (indicative of a change in refractive index of the chromatin) ∼34 s post-laser exposure corresponds spatially to the accumulation of Nbs1, Ku and ubiquitin. This study demonstrates that chromosomes selectively altered in mitosis initiate the DNA damage response within 30 s and that the accumulation of proteins are visually represented by phase-dark material at the irradiation site, allowing us to determine the fate of the damage as cells enter G1. These results occur with two widely different laser systems, making this approach to study DNA damage responses in the mitotic phase generally available to many different labs. Additionally, we present a summary of most of the published laser studies on chromosomes in order to provide a general guide of the lasers and operating parameters used by other laboratories
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