2,458 research outputs found
Evolving temporal fuzzy association rules from quantitative data with a multi-objective evolutionary algorithm
A novel method for mining association rules that are both quantitative and temporal using a multi-objective evolutionary algorithm is presented. This method successfully identifies numerous temporal association rules that occur more frequently in areas of a dataset with specific quantitative values represented with fuzzy sets. The novelty of this research lies in exploring the composition of quantitative and temporal fuzzy association rules and the approach of using a hybridisation of a multi-objective evolutionary algorithm with fuzzy sets. Results show the ability of a multi-objective evolutionary algorithm (NSGA-II) to evolve multiple target itemsets that have been augmented into synthetic datasets
Casimir force on a piston
We consider a massless scalar field obeying Dirichlet boundary conditions on
the walls of a two-dimensional L x b rectangular box, divided by a movable
partition (piston) into two compartments of dimensions a x b and (L-a) x b. We
compute the Casimir force on the piston in the limit L -> infinity. Regardless
of the value of a/b, the piston is attracted to the nearest end of the box.
Asymptotic expressions for the Casimir force on the piston are derived for a <<
b and a >> b.Comment: 10 pages, 1 figure. Final version, accepted for publication in Phys.
Rev.
Dimension dependent hypercontractivity for Gaussian kernels
We derive sharp, local and dimension dependent hypercontractive bounds on the
Markov kernel of a large class of diffusion semigroups. Unlike the dimension
free ones, they capture refined properties of Markov kernels, such as trace
estimates. They imply classical bounds on the Ornstein-Uhlenbeck semigroup and
a dimensional and refined (transportation) Talagrand inequality when applied to
the Hamilton-Jacobi equation. Hypercontractive bounds on the Ornstein-Uhlenbeck
semigroup driven by a non-diffusive L\'evy semigroup are also investigated.
Curvature-dimension criteria are the main tool in the analysis.Comment: 24 page
Dark Energy From Vacuum Fluctuations
We describe briefly a novel interpretation of the physical nature of dark
energy (DE), based on the vacuum fluctuations model by Gurzadyan & Xue, and
describe an internally consistent solution for the behavor of DE as a function
of redshift. A key choice is the nature of the upper bound used for the
computation of energy density contributions by vacuum modes. We show that use
of the comoving horizon radius produces a viable model, whereas use of the
proper horizon radius is inconsistent with the observations. After introduction
of a single phenomenological parameter, the model is consistent with all of the
curently available data, and fits them as well as the standard cosmological
constant model, while making testable predictions. While some substantial
interpretative uncertainties remain, future developments of this model may lead
to significant new insights into the physical nature of DE.Comment: To appear in Proc. UCLA Conference "Dark Matter 2006", eds. D. Cline
et al., Nuclear Pysics B, in press (2006); 5 page
Exogenous application of plant growth regulators induce chilling tolerance in direct seeded super and non-super rice seedlings through modulations in morpho-physiological attributes
Recently, super rice has gained much importance due to its high yield potential while exogenous application of plant growth regulators (PGRs) is an important aspect in plant development and defense responses under stress conditions. In this study we conducted two pot experiments. Firstly, four super rice cultivars, viz. Peizataifeng, Huayou 213, Yuxiangyouzhan and Huahang 31 were subjected to a series of five chilling temperatures, i.e. 11 °C, 12 °C, 13 °C, 14 °C and 15 °C (day/night) for about 25–27 days. Secondly, seeds of Peizataifeng (super rice) and Yuejingsimiao 2 (non-super rice) were then treated with different combinations of salicylic acid (SA), brassinolide (BR), calcium chloride (CaCl2) and fulvic acid (FA) and then exposed to chilling stress at 13 °C for four days. Resultantly, Peizataifen (super rice) was found with the lowest seedling survival rate at all chilling temperatures among all four super rice cultivars, however, it was still found more resistant when compared with Yuejingsimiao 2 (non-super rice) in the second experiment. Furthermore synergistic effect of all PGRs alleviated low temperature stress in both rice cultivars by improving seedling survival rates, leaf area, seedling dry weight, seedling height, root morphology and by modulating antioxidant enzymes, improving proline content and lowering lipid peroxidation
Varied Signature Splitting Phenomena in Odd Proton Nuclei
Varied signature splitting phenomena in odd proton rare earth nuclei are
investigated. Signature splitting as functions of and in the angular
momentum projection theory is explicitly shown and compared with those of the
particle rotor model. The observed deviations from these rules are due to the
band mixings. The recently measured Ta high spin data are taken as a
typical example where fruitful information about signature effects can be
extracted. Six bands, two of which have not yet been observed, were calculated
and discussed in detail in this paper. The experimentally unknown band head
energies are given
Investigation of the Dimensional Variation of Microstructures Through the μMIM Process
The mass production of components with dimensions in the micron and sub-micron range is anticipated to be one of the leading technology areas for the present century and to be of high market potential. Micro metal injection molding (μMIM) has the potential to be an important contributor to this industry as it can produce precise metallic microstructures in large quantities at a relatively low production cost. The μMIM process is a miniaturization of metal injection molding (MIM) methods. The process comprises of four main steps: mixing, injection molding, debinding and sintering. A metallic powder is mixed with a binder system to form the feedstock. The feedstock is then
injection molded into the required shape and the binder removed via thermal or other means. The final microstructures are obtained by sintering the remaining powder in a controlled
environment. In this work, the dimensional variation of the microstructures, in particular the warpage, roughness and volume variation, at each stage of the μMIM process was quantified and compared. The results of a preliminary study of the sensitivity of warpage of the microstructures to the
packing pressure are also reported.Singapore-MIT Alliance (SMA
Transmission Properties of the oscillating delta-function potential
We derive an exact expression for the transmission amplitude of a particle
moving through a harmonically driven delta-function potential by using the
method of continued-fractions within the framework of Floquet theory. We prove
that the transmission through this potential as a function of the incident
energy presents at most two real zeros, that its poles occur at energies
(), and that the
poles and zeros in the transmission amplitude come in pairs with the distance
between the zeros and the poles (and their residue) decreasing with increasing
energy of the incident particle. We also show the existence of non-resonant
"bands" in the transmission amplitude as a function of the strength of the
potential and the driving frequency.Comment: 21 pages, 12 figures, 1 tabl
Anomalous Crossing Frequency in Odd Proton Nuclei
A generic explanation for the recently observed anomalous crossing
frequencies in odd proton rare earth nuclei is given. As an example, the proton
band in Ta is discussed in detail by using the
angular momentum projection theory. It is shown that the quadrupole pairing
interaction is decisive in delaying the crossing point and the changes in
crossing frequency along the isotope chain are due to the different neutron
shell fillings
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