72 research outputs found
Camera distortion self-calibration using the plumb-line constraint and minimal Hough entropy
In this paper we present a simple and robust method for self-correction of
camera distortion using single images of scenes which contain straight lines.
Since the most common distortion can be modelled as radial distortion, we
illustrate the method using the Harris radial distortion model, but the method
is applicable to any distortion model. The method is based on transforming the
edgels of the distorted image to a 1-D angular Hough space, and optimizing the
distortion correction parameters which minimize the entropy of the
corresponding normalized histogram. Properly corrected imagery will have fewer
curved lines, and therefore less spread in Hough space. Since the method does
not rely on any image structure beyond the existence of edgels sharing some
common orientations and does not use edge fitting, it is applicable to a wide
variety of image types. For instance, it can be applied equally well to images
of texture with weak but dominant orientations, or images with strong vanishing
points. Finally, the method is performed on both synthetic and real data
revealing that it is particularly robust to noise.Comment: 9 pages, 5 figures Corrected errors in equation 1
The Ethics of IT Professionals in Japan and China
The ethical integrity and accountability of Information Technology (IT) professionals is important given our reliance on various forms of IT. We examined the applicability of Lawrence Kohlbergâs theory of Cognitive Moral Development (CMD) in non-Western contexts by investigating the ethical values of IT professionals in Asiaâs two largest economies. Analysis of survey data from Japan (n=289) and China (n=290) indicates support for the basic six-stage model of CMD. The concept of abiding by universal laws and rules (termed stage 4 reasoning by Kohlberg) was widely accepted by IT professionals in both Japan and China, despite the Confucian cultural emphasis on personal relationships with particularistic obligations. However, differences between Japanese and Chinese IT professionals were found while, in direct contrast with the stage-wise theory of CMD, the respondents from Japan and especially China exhibited significant volatility, reasoning at different stages simultaneously. The implications of these findings for research and practice are discussed
Sub-Poissonian statistics in order-to-chaos transition
We study the phenomena at the overlap of quantum chaos and nonclassical
statistics for the time-dependent model of nonlinear oscillator. It is shown in
the framework of Mandel Q-parameter and Wigner function that the statistics of
oscillatory excitation number is drastically changed in order-to chaos
transition. The essential improvement of sub-Poissonian statistics in
comparison with an analogous one for the standard model of driven anharmonic
oscillator is observed for the regular operational regime. It is shown that in
the chaotic regime the system exhibits the range of sub- and super-Poissonian
statistics which alternate one to other depending on time intervals. Unusual
dependence of the variance of oscillatory number on the external noise level
for the chaotic dynamics is observed.Comment: 9 pages, RevTeX, 14 figure
Soliton back-action evading measurement using spectral filtering
We report on a back-action evading (BAE) measurement of the photon number of
fiber optical solitons operating in the quantum regime. We employ a novel
detection scheme based on spectral filtering of colliding optical solitons. The
measurements of the BAE criteria demonstrate significant quantum state
preparation and transfer of the input signal to the signal and probe outputs
exiting the apparatus, displaying the quantum-nondemolition (QND) behavior of
the experiment.Comment: 5 pages, 5 figure
Exact quantum phase model for mesoscopic Josephson junctions
Starting from the two-mode Bose-Hubbard model, we derive an exact version of the standard Mathieu equation governing the wave function of a Josephson junction. For a finite number of particles N, we find an additional cos 2 phi term in the potential. We also find that the inner product in this representation is nonlocal in phi. Our model exhibits phenomena, such as pi oscillations, which are not found in the standard phase model, but have been predicted from Gross-Pitaevskii mean-field theory
Chaos in a double driven dissipative nonlinear oscillator
We propose an anharmonic oscillator driven by two periodic forces of
different frequencies as a new time-dependent model for investigating quantum
dissipative chaos. Our analysis is done in the frame of statistical ensemble of
quantum trajectories in quantum state diffusion approach. Quantum dynamical
manifestation of chaotic behavior, including the emergence of chaos, properties
of strange attractors, and quantum entanglement are studied by numerical
simulation of ensemble averaged Wigner function and von Neumann entropy.Comment: 9 pages, 18 figure
An alternative electric-field spectrum for laser-driven atomic systems
We adopt an open systems perspective to calculate the power spectrum associated with the electric field generated by an atomic dipole moment undergoing resonant laser-driving. This spectrum has a similar triplet shape to the Mollow spectrum and contains a similar amount of information. This is surprising, since the Mollow triplet derives from the Glauber two-time correlation function, which represents the average energy-intensity of a superposition of waves taken at different times. In contrast, our spectrum derives from a correlation function defined in terms of single-time expectation values of the electric source-field. Although they are derived from very different correlation functions, both spectra reflect the quantum-mechanical level-structure of the atomic source
Alignment of inhaled chronic obstructive pulmonary disease therapies with published strategies :analysis of the Global Initiative for Chronic Obstructive Lung Disease recommendations in SpiroMics
Rationale: Despite awareness of chronic obstructive pulmonary disease (COPD) treatment recommendations, uptake is poor. The Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) spans 2010-2016, providing an opportunity to assess integration of 2011 Global Initiative for Obstructive Lung Disease (GOLD) treatment strategies over time in a large observational cohort study. Objectives: To evaluate how COPD treatment aligns with 2011 GOLD strategies and determine factors associated with failure to align with recommendations. Methods: Information on inhaled medication use collected via questionnaire annually for 4 years was compiled into therapeutic classes (long-acting antimuscarinic agent, long-acting b-agonist, inhaled corticosteroids [ICS], and combinations thereof). Medications were not modified by SPIROMICS investigators. 2011 GOLD COPD categories A, B, C, and D were assigned. Alignment of inhaler regimen with first-/second-line GOLD recommendations was determined, stratifying into recommendation aligned or nonaligned. Recommendation-nonaligned participants were further stratified into overuse and underuse categories. Results: Of 1,721 participants with COPD, at baseline, 52% of regimens aligned with GOLD recommendations. Among participants with nonaligned regimens, 46% reported underuse, predominately owing to lack of long-acting inhalers in GOLD category D. Of the 54% reporting overuse, 95% were treated with nonindicated ICS-containing regimens. Among 431 participants with 4 years of follow-up data, recommendation alignment did not change over time. When we compared 2011 and 2017 recommendations, we found that 47% did not align with either set of recommendations, whereas 35% were in alignment with both recommendations. Conclusions: Among SPIROMICS participants with COPD, nearly 50% reported inhaler regimens that did not align with GOLD recommendations. Nonalignment was driven largely by overuse of ICS regimens in milder disease and lack of long-acting inhalers in severe disease
Associations Among 25-Hydroxyvitamin D Levels, Lung Function, and Exacerbation Outcomes in COPD: An Analysis of the SPIROMICS Cohort
Background: The relationship between 25-hydroxyvitamin D (25-OH-vitamin D) and COPD outcomes remains unclear. Using the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS), we determined associations among baseline 25-OH-vitamin D and cross-sectional and longitudinal lung function and COPD exacerbations. Methods: Serum 25-OH-vitamin D level was measured in stored samples from 1,609 SPIROMICS participants with COPD. 25-OH-vitamin D levels were modeled continuously and dichotomized as deficient (< 20 ng/mL) vs not deficient (â„ 20 ng/mL). Outcomes of interest included % predicted FEV1 (current and 1-year longitudinal decline) and COPD exacerbations (separately any and severe, occurring in prior year and first year of follow-up). Results: Vitamin D deficiency was present in 21% of the cohort and was more prevalent in the younger, active smokers, and blacks. Vitamin D deficiency was independently associated with lower % predicted FEV1 (by 4.11%) at enrollment (95% CI, â6.90% to â1.34% predicted FEV1; P =.004), 1.27% predicted greater rate of FEV1 decline after 1 year (95% CI, â2.32% to â0.22% predicted/y; P =.02), and higher odds of any COPD exacerbation in the prior year (OR, 1.32; 95% CI, 1.00-1.74; P =.049). Each 10-ng/mL decrease in 25-OH-vitamin D was associated with lower baseline lung function (â1.04% predicted; 95% CI, â1.96% to â0.12% predicted; P =.03) and increased odds of any exacerbation in the year before enrollment (OR, 1.11; 95% CI, 1.01-1.22; P =.04). Conclusions: Vitamin D deficiency is associated with worse cross-sectional and longitudinal lung function and increased odds of prior COPD exacerbations. These findings identify 25-OH-vitamin D levels as a potentially useful marker of adverse COPD-related outcomes
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