191 research outputs found
Mining compact predictive pattern sets using classification model
In this paper, we develop a new framework for mining predictive patterns that aims to describe compactly the condition (or class) of interest. Our framework relies on a classification model that considers and combines various predictive pattern candidates and selects only those that are important for improving the overall class prediction performance. We test our approach on data derived from MIMIC-III EHR database, focusing on patterns predictive of sepsis. We show that using our classification approach we can achieve a significant reduction in the number of extracted patterns compared to the state-of-the-art methods based on minimum predictive pattern mining approach, while preserving the overall classification accuracy of the model
FIBS: A Generic Framework for Classifying Interval-based Temporal Sequences
We study the problem of classifying interval-based temporal sequences
(IBTSs). Since common classification algorithms cannot be directly applied to
IBTSs, the main challenge is to define a set of features that effectively
represents the data such that classifiers can be applied. Most prior work
utilizes frequent pattern mining to define a feature set based on discovered
patterns. However, frequent pattern mining is computationally expensive and
often discovers many irrelevant patterns. To address this shortcoming, we
propose the FIBS framework for classifying IBTSs. FIBS extracts features
relevant to classification from IBTSs based on relative frequency and temporal
relations. To avoid selecting irrelevant features, a filter-based selection
strategy is incorporated into FIBS. Our empirical evaluation on eight
real-world datasets demonstrates the effectiveness of our methods in practice.
The results provide evidence that FIBS effectively represents IBTSs for
classification algorithms, which contributes to similar or significantly better
accuracy compared to state-of-the-art competitors. It also suggests that the
feature selection strategy is beneficial to FIBS's performance.Comment: In: Big Data Analytics and Knowledge Discovery. DaWaK 2020. Springer,
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Physical Aspects of Pseudo-Hermitian and -Symmetric Quantum Mechanics
For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a
canonical orthonormal basis in which a previously introduced unitary mapping of
H to a Hermitian Hamiltonian h takes a simple form. We use this basis to
construct the observables O of the quantum mechanics based on H. In particular,
we introduce pseudo-Hermitian position and momentum operators and a
pseudo-Hermitian quantization scheme that relates the latter to the ordinary
classical position and momentum observables. These allow us to address the
problem of determining the conserved probability density and the underlying
classical system for pseudo-Hermitian and in particular PT-symmetric quantum
systems. As a concrete example we construct the Hermitian Hamiltonian h, the
physical observables O, the localized states, and the conserved probability
density for the non-Hermitian PT-symmetric square well. We achieve this by
employing an appropriate perturbation scheme. For this system, we conduct a
comprehensive study of both the kinematical and dynamical effects of the
non-Hermiticity of the Hamiltonian on various physical quantities. In
particular, we show that these effects are quantum mechanical in nature and
diminish in the classical limit. Our results provide an objective assessment of
the physical aspects of PT-symmetric quantum mechanics and clarify its
relationship with both the conventional quantum mechanics and the classical
mechanics.Comment: 45 pages, 13 figures, 2 table
Coherent and squeezed states of quantum Heisenberg algebras
Starting from deformed quantum Heisenberg Lie algebras some realizations are
given in terms of the usual creation and annihilation operators of the standard
harmonic oscillator. Then the associated algebra eigenstates are computed and
give rise to new classes of deformed coherent and squeezed states. They are
parametrized by deformed algebra parameters and suitable redefinitions of them
as paragrassmann numbers. Some properties of these deformed states also are
analyzed.Comment: 32 pages, 3 figure
Accreting Black Holes
This chapter provides a general overview of the theory and observations of
black holes in the Universe and on their interpretation. We briefly review the
black hole classes, accretion disk models, spectral state classification, the
AGN classification, and the leading techniques for measuring black hole spins.
We also introduce quasi-periodic oscillations, the shadow of black holes, and
the observations and the theoretical models of jets.Comment: 41 pages, 18 figures. To appear in "Tutorial Guide to X-ray and
Gamma-ray Astronomy: Data Reduction and Analysis" (Ed. C. Bambi, Springer
Singapore, 2020). v3: fixed some typos and updated some parts. arXiv admin
note: substantial text overlap with arXiv:1711.1025
Predictors of Breast and Cervical Cancer Screening among Chamorro Women in Southern California
This study examined the role of sociodemographic characteristics, health insurance, cancer knowledge, perceived health risk, and having a recent physiciansâ visit on breast and cervical cancer screening utilization among a randomly selected group of Chamorro women (nâ=â250) residing in San Diego, California. Data were collected by a telephone survey and analyzed using multiple logistic regression models. After adjusting for covariates, having a recent full exam was the strongest predictor of having had a Pap exam in the past 2Â years for women 21Â years and older and a clinical breast exam in the past 2Â years for women 40Â years and over
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