45,847 research outputs found
Recognition of human body posture from a cloud of 3D data points using wavelet transform coefficients
Addresses the problem of recognizing a human body posture from a cloud of 3D points acquired by a human body scanner. Motivated by finding a representation that embodies a high discriminatory power between posture classes, a new type of feature is suggested, namely the wavelet transform coefficients (WTC) of the 3D data-point distribution projected on to the space of spherical harmonics. A feature selection technique is developed to find those features with high discriminatory power. Integrated within a Bayesian classification framework and compared with other standard features, the WTC showed great capability in discriminating between close postures. The qualities of the WTC features were also reflected in the experimental results carried out with artificially generated postures, where the WTC obtained the best classification rat
A topological approach for segmenting human body shape
Segmentation of a 3D human body, is a very challenging problem in applications exploiting human scan data. To tackle this problem, the paper proposes a topological approach based on the discrete Reeb graph (DRG) which is an extension of the classical Reeb graph to handle unorganized clouds of 3D points. The essence of the approach concerns detecting critical nodes in the DRG, thereby permitting the extraction of branches that represent parts of the body. Because the human body shape representation is built upon global topological features that are preserved so long as the whole structure of the human body does not change, our approach is quite robust against noise, holes, irregular sampling, frame change and posture variation. Experimental results performed on real scan data demonstrate the validity of our method
Consequences of R-Parity violating interactions for anomalies in and
We investigate the possibility of explaining the enhancement in semileptonic
decays of , the anomalies induced by in and violation of lepton
universality in
within the framework of R-parity violating (RPV) MSSM. Exchange of down type
right-handed squark coupled to quarks and leptons yield interactions which are
similar to leptoquark induced interactions that have been proposed to explain
the by tree level interactions and anomalies by loop induced interactions, simultaneously. However,
the Yukawa couplings in such theories have severe constraints from other rare
processes in and decays. Although this interaction can provide a viable
solution to anomaly, we show that with the severe constraint from
, it is impossible to solve the anomalies in process simultaneously.Comment: RevTex, 13 pages, three figures. In our earlier version, we had
neglected a contribution to C^{NP}_9 and obtained erroneous conclusions which
we have corrected them in this versio
The effect of piston bowl temperature on diesel exhaust emissions
In modern, high-speed, direct injection diesel engines for passenger vehicles, there is extensive impingement of the fuel sprays on to the piston bowl walls. Recent trends towards smaller engine sizes, equipped with high-pressure common-rail fuel injection systems, have tended to increase the spray/piston wall interaction. This paper describes tests carried out in a high-speed direct injection automotive diesel engine, during which the temperature of the piston was increased in a controlled manner between 189 and 227 degrees C while being continuously monitored. The aim of the work was to quantify the effects of piston temperature on pollutant exhaust emissions. The results show a significant reduction in unburned hydrocarbon emission, a significant increase in smoke emission, and no significant change in the emission of oxides of nitrogen. The increase in smoke emission cannot be ascribed to changes in the engine volumetric efficiency or air-fuel ratio. The paper demonstrates that fuel spray deposition on the piston surface was in the form of a thin film that did not experience bulk boiling. A number of suggestions are put forward to help explain the observed changes in exhaust emissions with increasing piston temperature
Triple Neutral Gauge Boson Couplings in Noncommutative Standard Model
It has been shown recently that the triple neutral gauge boson couplings are
not uniquely determined in noncommutative extension of the Standard Model
(NCSM). Depending on specific schemes used, the couplings are different and may
even be zero. To distinguish different realizations of the NCSM, additional
information either from theoretical or experimental considerations is needed.
In this paper we show that these couplings can be uniquely determined from
considerations of unification of electroweak and strong interactions. Using
SU(5) as the underlying theory and integrating out the heavy degrees of
freedom, we obtain unique non-zero new triple , , , , , and couplings at the
leading order in the NCSM. We also briefly discuss experimental implications.Comment: 8 pages, Latex, no figur
A discrete Reeb graph approach for the segmentation of human body scans
Segmentation of 3D human body (HB) scan is a very challenging problem in applications exploiting human scan data. To tackle this problem, we propose a topological approach based on discrete Reeb graph (DRG) which is an extension of the classical Reeb graph to unorganized cloud of 3D points. The essence of the approach is detecting critical nodes in the DRG thus permitting the extraction of branches that represent the body parts. Because the human body shape representation is built upon global topological features that are preserved so long as the whole structure of the human body does not change, our approach is quite robust against noise, holes, irregular sampling, moderate reference change and posture variation. Experimental results performed on real scan data demonstrate the validity of our method
Three-Dimensional Phase-Kink State in Thick Stack of Josephson Junctions and Terahertz Radiation
The dynamics of superconductivity phase in thick stack of Josephson junctions
with strong inductive coupling, such as the one realized in layered high-
cuprates and possibly the recently discovered FeAs-based superconductors, is
investigated under a c-axis bias voltage and in the absence of an external
magnetic field. The kink state found previously by the present authors is
extended to three dimensions for both rectangular and cylindrical geometries.
The IV characteristics are calculated and the distributions of electromagnetic
field inside the samples are clarified. The solution for a cylindrical mesa
exhibits a higher resonating frequency than that of a square mesa with the same
linear size by a factor of . More importantly, from the radius
dependence of the resonance frequency for the cylinder geometry it is possible
to confirm directly the kink state, and thus to reveal the mechanism of the
strong radiation discovered in recent experiments.Comment: 6 pages, 8 figures. to be published in Phys. Rev. B. to be published
in Phys. Rev.
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