7,012 research outputs found
Multivariate time series classification with temporal abstractions
The increase in the number of complex temporal datasets collected today has prompted the development of methods that extend classical machine learning and data mining methods to time-series data. This work focuses on methods for multivariate time-series classification. Time series classification is a challenging problem mostly because the number of temporal features that describe the data and are potentially useful for classification is enormous. We study and develop a temporal abstraction framework for generating multivariate time series features suitable for classification tasks. We propose the STF-Mine algorithm that automatically mines discriminative temporal abstraction patterns from the time series data and uses them to learn a classification model. Our experimental evaluations, carried out on both synthetic and real world medical data, demonstrate the benefit of our approach in learning accurate classifiers for time-series datasets. Copyright © 2009, Assocation for the Advancement of ArtdicaI Intelligence (www.aaai.org). All rights reserved
The Quantum Cocktail Party
We consider the problem of decorrelating states of coupled quantum systems.
The decorrelation can be seen as separation of quantum signals, in analogy to
the classical problem of signal-separation rising in the so-called
cocktail-party context. The separation of signals cannot be achieved perfectly,
and we analyse the optimal decorrelation map in terms of added noise in the
local separated states. Analytical results can be obtained both in the case of
two-level quantum systems and for Gaussian states of harmonic oscillators.Comment: 4 pages, 2figures, revtex
A genetic algorithm-assisted semi-adaptive MMSE multi-user detection for MC-CDMA mobile communication systems
In this work, a novel Minimum-Mean Squared-Error (MMSE) multi-user detector is proposed for MC-CDMA transmission systems working over mobile radio channels characterized by time-varying multipath fading. The proposed MUD algorithm is based on a Genetic Algorithm (GA)-assisted per-carrier MMSE criterion. The GA block works in two successive steps: a training-aided step aimed at computing the optimal receiver weights using a very short training sequence, and a decision-directed step aimed at dynamically updating the weights vector during a channel coherence period. Numerical results evidenced BER performances almost coincident with ones yielded by ideal MMSE-MUD based on the perfect knowledge of channel impulse response. The proposed GA-assisted MMSE-MUD clearly outperforms state-of-the-art adaptive MMSE receivers based on deterministic gradient algorithms, especially for high number of transmitting users
Quantum state decorrelation
We address the general problem of removing correlations from quantum states
while preserving local quantum information as much as possible. We provide a
complete solution in the case of two qubits, by evaluating the minimum amount
of noise that is necessary to decorrelate covariant sets of bipartite states.
We show that two harmonic oscillators in arbitrary Gaussian state can be
decorrelated by a Gaussian covariant map. Finally, for finite-dimensional
Hilbert spaces, we prove that states obtained from most cloning channels (e.g.,
universal and phase-covariant cloning) can be decorrelated only at the expense
of a complete erasure of information about the copied state. More generally, in
finite dimension, cloning without correlations is impossible for continuous
sets of states. On the contrary, for continuos variables cloning, a slight
modification of the customary set-up for cloning coherent states allows one to
obtain clones without correlations.Comment: 11 pages, 2 figures, RevTex
VERTICAL JUMP CHARACTERISTICS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION
The purpose of this study was to compare two-legged countermovement vertical jump characteristics between operated and non-operated lower limbs of twelve recreational athletes who had undergone unilateral ACL surgical reconstruction. A control group of eight uninjured athletes was employed. Bilateral vertical ground reaction forces, joint angles, moments and powers patterns were measured and statistically analysed. The examination of the angular kinematics revealed for the injured limb a significant reduction of the knee and ankle extension angles at the take off and an ankle ROM reduction. Examining peak moments and powers the injured knee exhibited significant lower values. The reduction of the knee peak power seems to be compensated in most of the subjects by an increase of the omolateral ankle peak power
Generating qudits with d=3,4 encoded on two-photon states
We present an experimental method to engineer arbitrary pure states of qudits
with d=3,4 using linear optics and a single nonlinear crystal.Comment: 4 pages, 1 eps figure. Minor changes. The title has been changed for
publication on Physical Review
Flavor chemistry of virgin olive oil: An overview
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth. The present review aims to give an overview on VOO flavor, with particular emphasis on the mechanisms affecting its production and release during a tasting
X-ray method to study temperature-dependent stripe domains in MnAs/GaAs(001)
MnAs films grown on GaAs (001) exhibit a progressive transition between
hexagonal (ferromagnetic) and orthorhombic (paramagnetic) phases at wide
temperature range instead of abrupt transition during the first-order phase
transition. The coexistence of two phases is favored by the anisotropic strain
arising from the constraint on the MnAs films imposed by the substrate. This
phase coexistence occurs in ordered arrangement alternating periodic terrace
steps. We present here a method to study the surface morphology throughout this
transition by means of specular and diffuse scattering of soft x-rays, tuning
the photon energy at the Mn 2p resonance. The results show the long-range
arrangement of the periodic stripe-like structure during the phase coexistence
and its period remains constant, in agreement with previous results using other
techniques.Comment: 4 pages, 4 figures, submitted to Applied Physics Letter
The Noble Method in the dairy sector as a sustainable production system to improve the nutritional composition of dairy products: A review
Sustainable production systems in line with consumer expectations are attractive for the dairy sector.
The objective of this review is to examine the benefits of an Italian method, named the Noble Method (‘Metodo Nobile ’), in order to improve the nutritional properties of milk and environmental sustainability. The prohibition of silage and the use of polyphite pastures are some of the rules
established by the Noble Method. The greater amount of unsaturated fatty acids and other beneficial
compounds found in milk and dairy products produced by using milk from animals fed on well-managed pasture could have positive implications on consumers’ health
3-D KINEMATIC ANALYSIS OF CANOEING ON A SIMULATOR: DIFFERENCES BETWEEN ELITE, INTERMEDIATE AND NOVICE CANOISTS
Using 3-D kinematic analysis, this paper identified kinematic variables that govern successful performance in canoeing on a simulator. The presence of side-to-side asymmetries in selected linear and angular variables was investigated. Elite, intermediate and novice canoeists participated. Similar to previously results for symmetrical cyclic sport activities like cross-country skiing, running and cycling, elite athletes evidenced higher movement amplitude and a more symmetric behavior compared with intermediate and novice paddlers. The less experienced athletes evidenced more accentuated saddle and pelvis movements in the frontal plane. Aerobic and anaerobic capacities and technical skills developed over years of training may explain the reported difference
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