Abstract: The stereo matching problem, while having been present for several decades, continues to be an active area of research. The goal of this research is to find correspondences between elements found in a set of stereoscopic images. With these pairings, it is possible to infer the distance of objects within a scene, relative to the observer. Advancements in this field have led to experimentations with various techniques, from graph-cut energy minimization to artificial neural networks. At the basis of these techniques is a cost function, which is used to evaluate the likelihood of a particular match between points in each image. While at its core, the cost is based on comparing the image pixel data; there is a general lack of consistency as to what image data representation to use. This paper presents an experimental analysis to compare the effectiveness of more common image data representations. The goal is to determine the effectiveness of these data representations to reduce the cost for the correct correspondence relative to other possible matches.
Abstract: The elastic properties and fracture of two-dimensional
graphene were calculated purely from the atomic bonding (stretching
and bending) based on molecular mechanics method. Considering the
representative unit cell of graphene under various loading conditions,
the deformations of carbon bonds and the variations of the interlayer
distance could be realized numerically under the geometry constraints
and minimum energy assumption. In elastic region, it was found that
graphene was in-plane isotropic. Meanwhile, the in-plane deformation
of the representative unit cell is not uniform along armchair direction
due to the discrete and non-uniform distributions of the atoms. The
fracture of graphene could be predicted using fracture criteria based on
the critical bond length, over which the bond would break. It was
noticed that the fracture behavior were directional dependent, which
was consistent with molecular dynamics simulation results.
Abstract: With the necessity of increased processing capacity with less energy consumption; power aware multiprocessor system has gained more attention in the recent future. One of the additional challenges that is to be solved in a multi-processor system when compared to uni-processor system is job allocation. This paper presents a novel task dependent job allocation algorithm: Energy centric- Allocation (Ec-A) and Rate Monotonic (RM) scheduling to minimize energy consumption in a multiprocessor system. A simulation analysis is carried out to verify the performance increase with reduction in energy consumption and required number of processors in the system.
Abstract: Investigations of the unimolecular decomposition of
vinyl ethyl ether (VEE), vinyl propyl ether (VPE) and vinyl butyl
ether (VBE) have shown that activation of the molecule of a ether
results in formation of a cyclic construction - the transition state (TS),
which may lead to the displacement of the thermodynamic
equilibrium towards the reaction products. The TS is obtained by
applying energy minimization relative to the ground state of an ether
under the program MM2 when taking into account the hydrogen bond
formation between a hydrogen atom of alkyl residue and the extreme
atom of carbon of the vinyl group. The dissociation of TS up to the
products is studied by energy minimization procedure using the
mathematical program Gaussian. The obtained calculation data for
VEE testify that the decomposition of this ether may be conditioned
by hydrogen bond formation for two possible versions: when α- or β-
hydrogen atoms of the ethyl group are bound to carbon atom of the
vinyl group. Applying the same calculation methods to other ethers
(VPE and VBE) it is shown that only in the case of hydrogen bonding
between α-hydrogen atom of the alkyl residue and the extreme atom
of carbon of the vinyl group (αH---C) results in decay of theses
ethers.
Abstract: 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) catalyzes the conversion of HMG-CoA to mevalonate using NADPH and the enzyme is involved in rate-controlling step of mevalonate. Inhibition of HMGR is considered as effective way to lower cholesterol levels so it is drug target to treat hypercholesterolemia, major risk factor of cardiovascular disease. To discover novel HMGR inhibitor, we performed structure-based pharmacophore modeling combined with molecular dynamics (MD) simulation. Four HMGR inhibitors were used for MD simulation and representative structure of each simulation were selected by clustering analysis. Four structure-based pharmacophore models were generated using the representative structure. The generated models were validated used in virtual screening to find novel scaffolds for inhibiting HMGR. The screened compounds were filtered by applying drug-like properties and used in molecular docking. Finally, four hit compounds were obtained and these complexes were refined using energy minimization. These compounds might be potential leads to design novel HMGR inhibitor.
Abstract: This paper presents an improved image segmentation
model with edge preserving regularization based on the
piecewise-smooth Mumford-Shah functional. A level set formulation
is considered for the Mumford-Shah functional minimization in
segmentation, and the corresponding partial difference equations are
solved by the backward Euler discretization. Aiming at encouraging
edge preserving regularization, a new edge indicator function is
introduced at level set frame. In which all the grid points which is used
to locate the level set curve are considered to avoid blurring the edges
and a nonlinear smooth constraint function as regularization term is
applied to smooth the image in the isophote direction instead of the
gradient direction. In implementation, some strategies such as a new
scheme for extension of u+ and u- computation of the grid points and
speedup of the convergence are studied to improve the efficacy of the
algorithm. The resulting algorithm has been implemented and
compared with the previous methods, and has been proved efficiently
by several cases.
Abstract: This paper is concerned with an improved algorithm
based on the piecewise-smooth Mumford and Shah (MS) functional
for an efficient and reliable segmentation. In order to speed up
convergence, an additional force, at each time step, is introduced
further to drive the evolution of the curves instead of only driven by
the extensions of the complementary functions u + and u - . In our
scheme, furthermore, the piecewise-constant MS functional is
integrated to generate the extra force based on a temporary image that
is dynamically created by computing the union of u + and u - during
segmenting. Therefore, some drawbacks of the original algorithm,
such as smaller objects generated by noise and local minimal problem
also are eliminated or improved. The resulting algorithm has been
implemented in Matlab and Visual Cµ, and demonstrated efficiently
by several cases.