196 research outputs found
Lend Me a Hand: Auxiliary Image Data Helps Interaction Detection
In social settings, people interact in close proximity. When analyzing such encounters from video, we are typically interested in distinguishing between a large number of different interactions. Here, we address training deformable part models (DPMs) for the detection of such interactions from video, in both space and time. When we consider a large number of interaction classes, we face two challenges. First, we need to distinguish between interactions that are visually more similar. Second, it becomes more difficult to obtain sufficient specific training examples for each interaction class. In this paper, we address both challenges and focus on the latter. Specifically, we introduce a method to train body part detectors from nonspecific images with pose information. Such resources are widely available. We introduce a training scheme and an adapted DPM formulation to allow for the inclusion of this auxiliary data. We perform cross-dataset experiments to evaluate the generalization performance of our method. We demonstrate that our method can still achieve decent performance, from as few as five training examples
Global Warming: Forecasts by Scientists versus Scientific Forecasts
In 2007, the Intergovernmental Panel on Climate Changeâs Working Group One, a panel of experts established by the World Meteorological Organization and the United Nations Environment Programme, issued its Fourth Assessment Report. The Report included predictions of dramatic increases in average world temperatures over the next 92 years and serious harm resulting from the predicted temperature increases. Using forecasting principles as our guide we asked: Are these forecasts a good basis for developing public policy? Our answer is ânoâ. To provide forecasts of climate change that are useful for policy-making, one would need to forecast (1) global temperature, (2) the effects of any temperature changes, and (3) the effects of feasible alternative policies. Proper forecasts of all three are necessary for rational policy making. The IPCC WG1 Report was regarded as providing the most credible long-term forecasts of global average temperatures by 31 of the 51 scientists and others involved in forecasting climate change who responded to our survey. We found no references in the 1056-page Report to the primary sources of information on forecasting methods despite the fact these are conveniently available in books, articles, and websites. We audited the forecasting processes described in Chapter 8 of the IPCCâs WG1 Report to assess the extent to which they complied with forecasting principles. We found enough information to make judgments on 89 out of a total of 140 forecasting principles. The forecasting procedures that were described violated 72 principles. Many of the violations were, by themselves, critical. The forecasts in the Report were not the outcome of scientific procedures. In effect, they were the opinions of scientists transformed by mathematics and obscured by complex writing. Research on forecasting has shown that expertsâ predictions are not useful in situations involving uncertainly and complexity. We have been unable to identify any scientific forecasts of global warming. Claims that the Earth will get warmer have no more credence than saying that it will get colder
Signatures of Relativistic Neutrinos in CMB Anisotropy and Matter Clustering
We present a detailed analytical study of ultra-relativistic neutrinos in
cosmological perturbation theory and of the observable signatures of
inhomogeneities in the cosmic neutrino background. We note that a modification
of perturbation variables that removes all the time derivatives of scalar
gravitational potentials from the dynamical equations simplifies their solution
notably. The used perturbations of particle number per coordinate, not proper,
volume are generally constant on superhorizon scales. In real space an
analytical analysis can be extended beyond fluids to neutrinos.
The faster cosmological expansion due to the neutrino background changes the
acoustic and damping angular scales of the cosmic microwave background (CMB).
But we find that equivalent changes can be produced by varying other standard
parameters, including the primordial helium abundance. The low-l integrated
Sachs-Wolfe effect is also not sensitive to neutrinos. However, the gravity of
neutrino perturbations suppresses the CMB acoustic peaks for the multipoles
with l>~200 while it enhances the amplitude of matter fluctuations on these
scales. In addition, the perturbations of relativistic neutrinos generate a
*unique phase shift* of the CMB acoustic oscillations that for adiabatic
initial conditions cannot be caused by any other standard physics. The origin
of the shift is traced to neutrino free-streaming velocity exceeding the sound
speed of the photon-baryon plasma. We find that from a high resolution, low
noise instrument such as CMBPOL the effective number of light neutrino species
can be determined with an accuracy of sigma(N_nu) = 0.05 to 0.09, depending on
the constraints on the helium abundance.Comment: 38 pages, 7 figures. Version accepted for publication in PR
Non-thermal dark matter via Affleck-Dine baryogenesis and its detection possibility
The formation and late time decays of Q-balls are generic consequences of the
Affleck-Dine (AD) baryogenesis. A substantial amount of the lightest
supersymmetry (SUSY) particles (LSPs) are produced non-thermally as the decay
products of these Q-balls. This requires a significantly large annihilation
cross section of the LSP so as not to overclose the universe, which predicts a
higgsino- or wino-like LSP instead of the standard bino LSP. We have reexamined
the AD baryogenesis with special attention to the late-time decays of the
Q-balls, and then specified the parameter regions where the LSPs produced by
the Q-ball decays result in a cosmologically interesting mass density of dark
matter by adopting several SUSY breaking models. This reveals new
cosmologically interesting parameter regions, which have not attracted much
attention so far. We have also investigated the prospects of direct and
indirect detection of these dark matter candidates, and found that there is an
intriguing possibility to detect them in various next generation dark matter
searches.Comment: 51 pages, 18 figures, version accepted for publication in Physical
Review
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The Political Economy of Failure: The Euro as an International Currency
How do international currencies get established and consolidated? What domestic and international political foundations support an international currency? And what kinds of macro-economic flows enable an international currency? In this essay we consider these perennial questions of modern IPE scholarship in reverse order to ask whether the euro could ever have become, or seek to become, a true international currency rivalling the US dollar, used not only for passive foreign exchange reserves but also as a major commercial currency outside the EU. We argue that the EU lacks the will, the ideas and the capacity to promote the euro into the status of an international currency. In this article, we concentrate on this final issue of capacity, as the will and ideas issues have already been well explored. Capacity is an issue coeval with, if not prior to, the first two issues. The EU's current institutional arrangements and its economic geography create macro-economic consequences that diminish the euro's capacity to operate as a top currency. These conflicts go beyond the well-recognized issue that the euro-zone is not an optimum currency area. Examining the euro's debilities sheds light not only on the euro's (in)capacity to rival the dollar as an international currency, but also on the future of both the euro and the dollar in the aftermath of the euro-zone crisis
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Does technology and Innovation Management improve Market Position? Empirical Evidence from Innovating Firms in South Africa
There is a growing recognition of the central role of technology and knowledge management for market success of organizations. Little is empirically know, however, about this relationship. Drawing on the South African Innovation Survey, a unique dataset on innovative behavior of South African firms in manufacturing and services, this paper investigates the question to what extent and in which ways do technology and innovation management activities affect firmsâ market position. Findings show that conducting technology strategy activities pays out. Moreover, especially a combination of internal and external technology audits seems to be beneficial for organizational performance
Effect of nesiritide in patients with acute decompensated heart failure
Background Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent. Methods We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days. Results Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P = 0.03) and 24 hours (68.2% vs. 66.1%, P = 0.007), but the prespecified level for significance (Pâ€0.005 for both assessments or Pâ€0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, â0.7 percentage points; 95% confidence interval [CI], â2.1 to 0.7; P = 0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, â0.4 percentage points; 95% CI, â1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P = 0.11). Conclusions Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.
Integrated motor drives: state of the art and future trends
With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system.
This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented
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