160,657 research outputs found
Vision-based hand gesture interaction using particle filter, principle component analysis and transition network
Vision-based human-computer interaction is becoming important nowadays. It offers natural interaction with computers and frees users from mechanical interaction devices, which is favourable especially for wearable computers. This paper presents a human-computer interaction system based on a conventional webcam and hand gesture recognition. This interaction system works in real time and enables users to control a computer cursor with hand motions and gestures instead of a mouse. Five hand gestures are designed on behalf of five mouse operations: moving, left click, left-double click, right click and no-action. An algorithm based on Particle Filter is used for tracking the hand position. PCA-based feature selection is used for recognizing the hand gestures. A transition network is also employed for improving the accuracy and reliability of the interaction system. This interaction system shows good performance in the recognition and interaction test
Orbital-resolved vortex core states in FeSe Superconductors: calculation based on a three-orbital model
We study electronic structure of vortex core states of FeSe superconductors
based on a t three-orbital model by solving the Bogoliubov-de
Gennes(BdG) equation self-consistently. The orbital-resolved vortex core states
of different pairing symmetries manifest themselves as distinguishable
structures due to different quasi-particle wavefunctions. The obtained vortices
are classified in terms of the invariant subgroups of the symmetry group of the
mean-field Hamiltonian in the presence of magnetic field. Isotropic and
anisotropic wave vortices have symmetry for each orbital, whereas
wave vortices show symmetry for orbitals
and symmetry for orbital. In the case of
wave vortices, hybridized-pairing between and orbitals gives
rise to a relative phase difference in terms of gauge transformed pairing order
parameters between and orbitals, which is essentially
caused by a transformation of co-representation of and
subgroup. The calculated local density of states(LDOS) of wave
vortices show qualitatively similar pattern with experiment results. The phase
difference of between and orbital-resolved
wave vortices can be verified by further experiment observation
A NLO analysis on fragility of dihadron tomography in high energy collisions
The dihadron spectra in high energy collisions are studied within the
NLO pQCD parton model with jet quenching taken into account. The high
dihadron spectra are found to be contributed not only by jet pairs close and
tangential to the surface of the dense matter but also by punching-through jets
survived at the center while the single hadron high spectra are only
dominated by surface emission. Consequently, the suppression factor of such
high- hadron pairs is found to be more sensitive to the initial gluon
density than the single hadron suppression factor.Comment: 4 pages, 4 figures, proceedings for the 19th international Conference
on ultra-relativistic nucleus-nucleus collisions (QM2006), Shanghai, China,
November 14-20, 200
Punch-through jets in collisions at RHIC/LHC
High single and dihadron production is studied within a NLO pQCD parton
model with jet quenching in high energy collisions at the RHIC/LHC
energy. A simultaneous -fit to both single and dihadron spectra can be
achieved within a narrow range of energy loss parameter. Punch-through jets are
found to result in the dihadron suppression factor slightly more sensitive to
medium than the single hadron suppression factor at RHIC. Such jets at LHC are
found to dominate high dihadron production and the resulting dihadron
spectra are more sensitive to the initial parton distribution functions than
the single hadron spectra.Comment: 4 pages, 4 figures, proceedings for the 20th international conference
on ultra-relativistic nucleus-nucleus collisions (QM2008), Jaipur, India,
February 4-10, 200
Photoacoustic generation of focused quasi-unipolar pressure pulses
The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries. In the focal region, the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface, with a time-averaged value equal to zero. This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries. For a free boundary, the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse
Tungsten fibre reinforced Zr-based bulk metallic glass composites
A Zr-based bulk metallic glass (BMG) alloy with the composition (Zr55Al10Ni5Cu30)98.5Si1.5 was used as the base material to form BMG composites. Tungsten fiber reinforced BMG composites were successfully fabricated by pressure metal infiltration technique, with the volume fraction of the tungsten fiber ranging from 10% to 70%. Microstructure and mechanical properties of the BMG composites were investigated. Tungsten reinforcement significantly increased the material’s ductility by changing the compressive failure mode from single shear band propagation to multiple shear bands propagation, and transferring stress from matrix to tungsten fibers
Comparative study of Steel-FRP, FRP and steel reinforced coral concrete beams in their flexural performance
In this paper, a comparative study of Carbon Fiber Reinforced Polymer (CFRP) Bar and Steel-Carbon Fiber Composite Bar (SCFCB) reinforced coral concrete beams are made through a series experimental tests and theoretical analysis. The flexural capacity, crack development and failure modes of CFRP and SCFCB reinforced coral concrete were investigated in detail. They are also compared to ordinary steel reinforced coral concrete beams. The results show that under the same condition of reinforcement ratio, the SCFCB reinforced beam exhibits better performance than those of the CFRP reinforced beams, and its stiffness is slightly lower than that of the steel reinforced beam. Under the same load condition, the crack width of the SCFCB beam is between the steel reinforced beam and the CFRP bar reinforced beam. Before the steel core yields, the crack growth rate of SCFCB beam is similar to the steel reinforced beam. SCFCB has a higher strength utilization rate, about 70% -85% of its ultimate strength. The current design guidance was also examined based on the test results. It was found that the existing design specifications for FRP reinforced normal concrete is not suitable for SCFCB reinforced coral concrete structures
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