13,116 research outputs found
A System for Induction of Oblique Decision Trees
This article describes a new system for induction of oblique decision trees.
This system, OC1, combines deterministic hill-climbing with two forms of
randomization to find a good oblique split (in the form of a hyperplane) at
each node of a decision tree. Oblique decision tree methods are tuned
especially for domains in which the attributes are numeric, although they can
be adapted to symbolic or mixed symbolic/numeric attributes. We present
extensive empirical studies, using both real and artificial data, that analyze
OC1's ability to construct oblique trees that are smaller and more accurate
than their axis-parallel counterparts. We also examine the benefits of
randomization for the construction of oblique decision trees.Comment: See http://www.jair.org/ for an online appendix and other files
accompanying this articl
Application of large eddy interaction model to a mixing layer
The large eddy interaction model (LEIM) is a statistical model of turbulence based on the interaction of selected eddies with the mean flow and all of the eddies in a turbulent shear flow. It can be utilized as the starting point for obtaining physical structures in the flow. The possible application of the LEIM to a mixing layer formed between two parallel, incompressible flows with a small temperature difference is developed by invoking a detailed similarity between the spectra of velocity and temperature
Metamorphism of cordierite gneisses from Eastern Ghat Granulite Terrain, Andhra Pradesh, South India
Cordierite-bearing metapelites of the Eastern Ghat granulite terrain occur in close association of Khondalites, quartzites, calc-silicate rocks and charnockites. Rocks occurring between Bobbili in the north and Guntur in the south of Andhra Pradesh are studied. The association of the mineral and textural relationships suggest the following metamorphic reactions: Garnet + sillimanite + quartz = cordierite, hypersthene + sillimanite + quartz = cordierite, sillimanite + spinel = cordierite + corundum, and biotite + quartz + sillimanite = cordierite + K=feldspar. Generally the minerals are not chemically zoned except garnet-biotite showing zoning when they come in close contact with one another. The potential thermometers are provided by the Fe-Mg distribution of coexisting biotite-garnet and cordierite-garnet. Conflicting interpretation of the P/T dependence of these reactions involving cordierite are due to H2O in the cordierite. The presence of alkali feldspar-quartz assemblage which is common in these gneisses will be constrained from melting only if H2O activity is less than 0.5. The piezometric array inferred is convex towards the temperature array, indicating a rapid and isothermal crustal uplift probably aided by thrust tectonics
Quantum Hall to Insulator Transition in the Bilayer Quantum Hall Ferromagnet
We describe a new phase transition of the bilayer quantum Hall ferromagnet at
filling fraction . In the presence of static disorder (modeled by a
periodic potential), bosonic spinons can undergo a superfluid-insulator
transition while preserving the ferromagnetic order. The Mott insulating phase
has an emergent U(1) photon, and the transition is between Higgs and Coulomb
phases of this photon. Physical consequences for charge and counterflow
conductivity, and for interlayer tunneling conductance in the presence of
quenched disorder are discussed.Comment: 4 pages, no figure
Economic Analysis of MGNREGA in the Drought–prone States of Karnataka, Rajasthan and Irrigation–dominated State of Andhra Pradesh
Using macro level data on MGNREGA performance in drought-prone states of Karnataka and Rajasthan as well as in irrigation-dominated state of Andhra Pradesh, this study has revealed that the impact of MGNREGA wage on the economic scarcity of labour is relatively modest when compared with the impact of hike in non-farm wages. Even though the provision of food security through public distribution system has contributed to the economic scarcity of labour, the relative hike in non-farm wages is contributing to higher economic scarcity of labour rather than PDS and MGNREGA wages. The study has suggested subsidies for farm mechanization should be provided in order to sustain food and livelihood security in the droughtprone as well as irrigation-dominant states of India.MGNREGA, Economic analysis, MGNREGA impact on labour supply, Economic scarcity of labour, Agricultural and Food Policy, I38, H53,
Nematic - Isotropic Transition in Porous Media - a Monte Carlo Study
We propose a lattice model to simulate the influence of porous medium on the
Nematic - Isotropic transition of liquid crystal confined to the pores. The
effects of pore size and pore connectivity are modelled through a disorder
parameter. Monte Carlo calculations based on the model leads to results that
compare well with experiments.Comment: 11 pages; 4 figure
Vibration analysis of rotor blades with an attached concentrated mass
The effect of an attached concentrated mass on the dynamics of helicopter rotor blades is determined. The point transmission matrix method was used to define, through three completely automated computer programs, the natural vibrational characteristics (natural frequencies and mode shapes) of rotor blades. The problems of coupled flapwise bending, chordwise bending, and torsional vibration of a twisted nonuniform blade and its special subcase pure torsional vibration are discussed. The orthogonality relations that exist between the natural modes of rotor blades with an attached concentrated mass are derived. The effect of pitch, rotation, and point mass parameters on the collective, cyclic, scissor, and pure torsional modes of a seesaw rotor blade is determined
Finite element analysis of plates with through cracks from higher order plate theory
A special crack tip element for plate bending is developed
using general crack tip solutions derived from a continuum
analysis through Reissnerls theory. It is demonstrated that
using this in combination with a conventional shear flexible
element, accurate results for bending stress intensity factor
can be obtained over a wide range of a plate thickness
parameter
Complex free energy landscapes in biaxial nematics and role of repulsive interactions : A Wang - Landau study
General quadratic Hamiltonian models, describing interaction between crystal
molecules (typically with symmetry) take into account couplings
between their uniaxial and biaxial tensors. While the attractive contributions
arising from interactions between similar tensors of the participating
molecules provide for eventual condensation of the respective orders at
suitably low temperatures, the role of cross-coupling between unlike tensors is
not fully appreciated. Our recent study with an advanced Monte Carlo technique
(entropic sampling) showed clearly the increasing relevance of this cross term
in determining the phase diagram, contravening in some regions of model
parameter space, the predictions of mean field theory and standard Monte Carlo
simulation results. In this context, we investigated the phase diagrams and the
nature of the phases therein, on two trajectories in the parameter space: one
is a line in the interior region of biaxial stability believed to be
representative of the real systems, and the second is the extensively
investigated parabolic path resulting from the London dispersion approximation.
In both the cases, we find the destabilizing effect of increased cross-coupling
interactions, which invariably result in the formation of local biaxial
organizations inhomogeneously distributed. This manifests as a small, but
unmistakable, contribution of biaxial order in the uniaxial phase.The free
energy profiles computed in the present study as a function of the two dominant
order parameters indicate complex landscapes, reflecting the difficulties in
the ready realization of the biaxial phase in the laboratory.Comment: 23 pages, 12 figure
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