404 research outputs found
New algorithmic developments in maximum consensus robust fitting
In many computer vision applications, the task of robustly estimating the set of parameters of
a geometric model is a fundamental problem. Despite the longstanding research efforts on robust
model fitting, there remains significant scope for investigation. For a large number of geometric
estimation tasks in computer vision, maximum consensus is the most popular robust fitting
criterion. This thesis makes several contributions in the algorithms for consensus maximization.
Randomized hypothesize-and-verify algorithms are arguably the most widely used class of
techniques for robust estimation thanks to their simplicity. Though efficient, these randomized
heuristic methods do not guarantee finding good maximum consensus estimates. To improve the
randomize algorithms, guided sampling approaches have been developed. These methods take
advantage of additional domain information, such as descriptor matching scores, to guide the
sampling process. Subsets of the data that are more likely to result in good estimates are prioritized
for consideration. However, these guided sampling approaches are ineffective when good
domain information is not available. This thesis tackles this shortcoming by proposing a new
guided sampling algorithm, which is based on the class of LP-type problems and Monte Carlo
Tree Search (MCTS). The proposed algorithm relies on a fundamental geometric arrangement
of the data to guide the sampling process. Specifically, we take advantage of the underlying tree
structure of the maximum consensus problem and apply MCTS to efficiently search the tree.
Empirical results show that the new guided sampling strategy outperforms traditional randomized
methods.
Consensus maximization also plays a key role in robust point set registration. A special case
is the registration of deformable shapes. If the surfaces have the same intrinsic shapes, their
deformations can be described accurately by a conformal model. The uniformization theorem
allows the shapes to be conformally mapped onto a canonical domain, wherein the shapes can be
aligned using a M¨obius transformation. The problem of correspondence-free M¨obius alignment
of two sets of noisy and partially overlapping point sets can be tackled as a maximum consensus
problem. Solving for the M¨obius transformation can be approached by randomized voting-type
methods which offers no guarantee of optimality. Local methods such as Iterative Closest Point
can be applied, but with the assumption that a good initialization is given or these techniques
may converge to a bad local minima. When a globally optimal solution is required, the literature
has so far considered only brute-force search. This thesis contributes a new branch-and-bound
algorithm that solves for the globally optimal M¨obius transformation much more efficiently.
So far, the consensus maximization problems are approached mainly by randomized algorithms,
which are efficient but offer no analytical convergence guarantee. On the other hand,
there exist exact algorithms that can solve the problem up to global optimality. The global methods,
however, are intractable in general due to the NP-hardness of the consensus maximization. To fill the gap between the two extremes, this thesis contributes two novel deterministic algorithms
to approximately optimize the maximum consensus criterion. The first method is based
on non-smooth penalization supported by a Frank-Wolfe-style optimization scheme, and another
algorithm is based on Alternating Direction Method of Multipliers (ADMM). Both of the
proposed methods are capable of handling the non-linear geometric residuals commonly used in
computer vision. As will be demonstrated, our proposed methods consistently outperform other
heuristics and approximate methods.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Computer Science, 201
Epidemiology of Leprosy in Vietnam and the Effectiveness of Multidrug Therapy (MDT) in the Management of the Disease
Leprosy is a chronic infection caused by the acid-fast, rod-shaped bacillus Mycobacterium leprae. Leprosy can be considered connected diseases that primarily affect the superficial tissues, especially the skin and peripheral nerves. The social and psychological effects of leprosy, as well as its highly visible debilities and sequelae, have resulted in a historical stigma associated with leprosy. Vietnam has seen a highly significant decrease in the prevalence rate (PR) of leprosy since 1983. From 1983 onwards, with the introduction of multidrug therapy (MDT), the prevalence of the disease has dropped to less than one case per 10,000 individuals from 1995. After over two decades, a total of 109 cases were registered with a prevalence rate of 0.01 per 10,000 population in 2017. It is clear that over the past 35 years, the profile of leprosy in Vietnam has been changed significantly followed by the treatment with MDT. Leprosy has become a rare disease in Vietnam. This chapter presents the trend in the epidemiology of leprosy in Vietnam from 1983 to 2018 and also mentions the effectiveness of multidrug therapy (MDT) in the management of this disease. Based on individual records and annual reports, the prevalence of registered cases, the number of new cases detected yearly, their sex, age, classification (MB, multibacillary; PB, paucibacillary) and disability status are carefully presented
SYNTHESIS OF COPPER-BASED NANOPARTICLE CATALYSTS BY DIFFERENT METHODS FOR TOTAL OXIDATION OF VOC
In this paper, the process of preparing 10 wt.% Cu/g-Al2O3 catalysts was studied by different methods. The changes in structure and texture of the catalysts were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR). The activities of catalyst were investigated completely oxidized VOC (toluene and n-butanol) on gas-phase reactions over the Cu/g-Al2O3 catalyst. The results were found that influence of the size of copper nanoparticles enhancing copper dispersion and selectivity of the catalyst prepared by non-thermal plasma (NTP) was superior to those obtained from the impregnation (WI) and deposition-precipitation (DP). The total oxidation of VOC to CO2 and H2O was achieved above 275oC. Compared to the WI and DP, the NTP method increased the oxidation efficiency by 15-30%
USING AN INTELLIGENT ANFIS-ONLINE CONTROLLER FOR STATCOM IN IMPROVING DYNAMIC VOLTAGE STABILITY
This research has introduced the intelligent ANFIS-Online controller of STATCOM for improving the dynamic voltage on the power network under a 3-phase short circuit fault. The ANFIS-Online is made using an artificial neural network identifier. And based on the identifier, the premise and consequent parameters of ANFIS are adjusted timely. To demonstrate the performance of the suggested controller, the transient waves are shown to describe the effectiveness of the intelligent ANFIS-Online controller to enhance the transient response of the research system under a 3-phase short circuit fault. It's shown that the suggested intelligent ANFIS-Online controller has provided waves better than the other controllers such as ANFIS controller, ANFIS-PSO controller, ANFIS-GA controller for STATCOM equipment to enhance transient voltage stability
Linear Approximation and Asymptotic Expansion of Solutions for a Nonlinear Carrier Wave Equation in an Annular Membrane with Robin-Dirichlet Conditions
This paper is devoted to the study of a nonlinear Carrier wave equation in an annular membrane associated with Robin-Dirichlet conditions. Existence and uniqueness of a weak solution are proved by using the linearization method for nonlinear terms combined with the Faedo-Galerkin method and the weak compact method. Furthermore, an asymptotic expansion of a weak solution of high order in a small parameter is established
Effects of yeast extract and methyl jasmonate on the enhancement of solasodine biosynthesis in cell cultures of Solanum hainanense Hance
In this work, the effects of the elicitors methyl jasmonate (MeJA) and yeast extract (YE) on the growth and solasodine production of Solanum hainanense cells were investigated. The results showed that various concentrations of MeJA (50-250 µM) and YE (1-4 g/L) have different eliciting influences. The increase of solasodine content induced by the elicitation of 3 g/L of YE and 50 µM of MeJA at the beginning of cell culture was about 1.9- and 1.3-fold, respectively, as compared with that of the non-elicitated cells. In general, YE (biotic elicitor) was more effective in enhancing solasodine production than MeJA (abiotic elicitor)
Phase Structure of Bose - Einstein Condensate in Ultra - Cold Bose Gases
The Bose - Einstein condensation of ultra - cold Bose gases is studied by means of the Cornwall - Jackiw - Tomboulis effective potential approach in the improved double - bubble approximation which preserves the Goldstone theorem. The phase structure of Bose - Einstein condensate associating with two different types of phase transition is systematically investigated. Its main feature is that the symmetry which was broken at zero temperature gets restore at higher temperature
Sintering behavior and physical properties of Bi0.5(Na1–xKx)0.5SnO3 lead-free ceramics
In this study, Bi0.5(Na1–xKx)0.5SnO3 (BNKS) ceramics (x = 0, 0.1, 0.2, 0.3, and 0.4) were fabricated via ultrasound wave before milling. The time of ball milling decreased from 20 to 1 h. The X-ray diffraction patterns show that the BNKS has a single-phase structure. When the potassium content increases, the phase structure of the ceramics changes from rhombohedral to tetragonal. When sintered at 1100 °C and x = 0.2, the ceramics’ physical properties are the best with the mass density of 5.59 g/cm3, the electromechanical coupling constants kp of 0,31 and kt of 0.27, the remanent polarization of 11.9 µC/cm; the dielectric constant εr of 1131, and the highest dielectric constant emax of 4800
Study change of the performance of airfoil of small wind turbine under low wind speed by CFD simulation
Renewable energy has received strong attention and investment to replace
fossil energy sources and reduce greenhouse gas emissions. Quite good and good
wind speed areas have been invested in building large-capacity wind farms for
many years. The low wind speed region occupies a very large on the world, which
has been interested in the exploitation of wind energy in recent years. In this
study, the original airfoil of S1010 operated at low wind speed was redesigned
to increase the aerodynamic efficiency of the airfoil by using XFLR5 software.
After, the new VAST-EPU-S1010 airfoil model was adjusted to the maximum
thickness and the maximum thickness position. It was simulated in low wind
speed conditions of 4-6 m/s by CFD simulation. The lift coefficient, drag
coefficient and / coefficient ratio were evaluated under the
effect of the angle of attack and the maximum thickness by using the
model. Simulation results show that the VAST-EPU-S1010 airfoil
achieved the greatest aerodynamic efficiency at the angle of attack of
3\,^{\circ}, the maximum thickness of 8\% and the maximum thickness position
of 20.32\%. The maximum value of / of the new airfoil at 6 m/s is
higher than at the 4 m/s by about 6.25\%.Comment: 19 pages, 21 figure
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