948 research outputs found
Information Splitting for Big Data Analytics
Many statistical models require an estimation of unknown (co)-variance
parameter(s) in a model. The estimation usually obtained by maximizing a
log-likelihood which involves log determinant terms. In principle, one requires
the \emph{observed information}--the negative Hessian matrix or the second
derivative of the log-likelihood---to obtain an accurate maximum likelihood
estimator according to the Newton method. When one uses the \emph{Fisher
information}, the expect value of the observed information, a simpler algorithm
than the Newton method is obtained as the Fisher scoring algorithm. With the
advance in high-throughput technologies in the biological sciences,
recommendation systems and social networks, the sizes of data sets---and the
corresponding statistical models---have suddenly increased by several orders of
magnitude. Neither the observed information nor the Fisher information is easy
to obtained for these big data sets. This paper introduces an information
splitting technique to simplify the computation. After splitting the mean of
the observed information and the Fisher information, an simpler approximate
Hessian matrix for the log-likelihood can be obtained. This approximated
Hessian matrix can significantly reduce computations, and makes the linear
mixed model applicable for big data sets. Such a spitting and simpler formulas
heavily depends on matrix algebra transforms, and applicable to large scale
breeding model, genetics wide association analysis.Comment: arXiv admin note: text overlap with arXiv:1605.0764
Exploiting Image-trained CNN Architectures for Unconstrained Video Classification
We conduct an in-depth exploration of different strategies for doing event
detection in videos using convolutional neural networks (CNNs) trained for
image classification. We study different ways of performing spatial and
temporal pooling, feature normalization, choice of CNN layers as well as choice
of classifiers. Making judicious choices along these dimensions led to a very
significant increase in performance over more naive approaches that have been
used till now. We evaluate our approach on the challenging TRECVID MED'14
dataset with two popular CNN architectures pretrained on ImageNet. On this
MED'14 dataset, our methods, based entirely on image-trained CNN features, can
outperform several state-of-the-art non-CNN models. Our proposed late fusion of
CNN- and motion-based features can further increase the mean average precision
(mAP) on MED'14 from 34.95% to 38.74%. The fusion approach achieves the
state-of-the-art classification performance on the challenging UCF-101 dataset
Device-free Localization using Received Signal Strength Measurements in Radio Frequency Network
Device-free localization (DFL) based on the received signal strength (RSS)
measurements of radio frequency (RF)links is the method using RSS variation due
to the presence of the target to localize the target without attaching any
device. The majority of DFL methods utilize the fact the link will experience
great attenuation when obstructed. Thus that localization accuracy depends on
the model which describes the relationship between RSS loss caused by
obstruction and the position of the target. The existing models is too rough to
explain some phenomenon observed in the experiment measurements. In this paper,
we propose a new model based on diffraction theory in which the target is
modeled as a cylinder instead of a point mass. The proposed model can will
greatly fits the experiment measurements and well explain the cases like link
crossing and walking along the link line. Because the measurement model is
nonlinear, particle filtering tracing is used to recursively give the
approximate Bayesian estimation of the position. The posterior Cramer-Rao lower
bound (PCRLB) of proposed tracking method is also derived. The results of field
experiments with 8 radio sensors and a monitored area of 3.5m 3.5m show that
the tracking error of proposed model is improved by at least 36 percent in the
single target case and 25 percent in the two targets case compared to other
models.Comment: This paper has been withdrawn by the author due to some mistake
Intake of dietary saturated fatty acids and risk of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition-Netherlands cohort: associations by types, sources of fatty acids and substitution by macronutrients.
The association between dietary saturated fatty acids (SFA) intake and type 2 diabetes (T2D) remains unclear. This study aimed at investigating the association between SFA intake and T2D risk based on (1) individual SFA (differing in carbon chain length), (2) food sources of SFA and (3) the substituting macronutrients
Comorbidity between neurodevelopmental disorders and childhood-onset type 1 diabetes
Childhood-onset type 1 diabetes and neurodevelopmental disorders, including
attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, and
intellectual disability, globally represent substantial health challenges. Each condition
places a substantial challenge on the individuals, their families, and healthcare systems.
The comorbidity between these two types of disorders has been a research focus, with
findings suggesting a higher prevalence of neurodevelopmental disorders among
individuals with childhood-onset type 1 diabetes. However, the underlying mechanism of
this comorbidity remains largely unknown, and the potential alteration in the health and
socio-economic outcomes due to this comorbidity remains unexplored. This thesis
aimed to elucidate the potential mechanisms behind the comorbidity between
childhood-onset type 1 diabetes and neurodevelopmental disorders and explore its
impact on health and education outcomes, with the goal of improving early detection,
prevention, and management strategies to enhance the quality of life for the affected
children and adolescents.
In Study I, we examined the impact of childhood-onset type 1 diabetes and the role of
glycemic control on the risk of subsequent neurodevelopmental disorders. We found
that individuals with childhood-onset type 1 diabetes had a higher risk of developing
neurodevelopmental disorders than the general population. Notably, this risk was
highest among those with less optimal glycemic control. These findings provided insight
into the role of glycemic control, a crucial diabetes-related factor, in the occurrence of
comorbidity between childhood-onset type 1 diabetes and neurodevelopmental
disorders.
In Study II, we investigated the potential contribution from shared familial liability to the
comorbidity between childhood-onset type 1 diabetes and neurodevelopmental
disorders. We found that the elevated risk of neurodevelopmental disorders did not only
appear in individuals with childhood-onset type 1 diabetes but also in their full-siblings.
The general family co-aggregation pattern and the results of the quantitative genetic
modeling, however, did not conclusively show that familial liability contributes to the
comorbidity. This ambiguity underscores the need for subsequent research to further
elucidate the underlying causes of this comorbidity.
In Study III, we explored the impacts of neurodevelopmental disorders on long-term
glycemic control and the risk of diabetic complications in individuals with childhoodonset
type 1 diabetes. We found that neurodevelopmental disorders, particularly ADHD
and intellectual disability, were associated with increased risk of poor glycemic control
and diabetic complications such as nephropathy and retinopathy. These observations
highlight that taking neurodevelopmental aspects into account can be crucial when
designing interventions and follow-ups for individuals with childhood-onset type 1
diabetes.
In Study IV, evaluated the interplay between childhood-onset type 1 diabetes, ADHD,
and academic outcomes, spanning from compulsory education to university levels. We
found that children and adolescents with both type 1 diabetes and ADHD were
significantly less likely to achieve educational milestones, crossing different education
levels, and had less favorable compulsory school performances compared to their peers
without these conditions. These results underline the importance of providing targeted
support to minimize the educational gap between the affected children and adolescents
and their peers
Prandtl boundary layer expansion with strong boundary layers for inhomogeneous incompressible magnetohydrodynamics equations in Sobolev framework
We consider the validity of Prandtl boundary layer expansion of solutions to
the initial boundary value problem for inhomogeneous incompressible
magnetohydrodynamics (MHD) equations in the half plane when both viscosity and
resistivity coefficients tend to zero, where the no-slip boundary condition is
imposed on velocity while the perfectly conducting condition is given on
magnetic field. Since there exist strong boundary layers, the essential
difficulty in establishing the uniform estimates of the error
functions comes from the unboundedness of curl of the strong boundary layers.
Under the assumptions that the viscosity and resistivity coefficients take the
same order of a small parameter and the initial tangential magnetic field has a
positive lower bound near the boundary, we prove the validity of Prandtl ansatz
in sense in Sobolev framework. Compared with the homogeneous
incompressible case considered in \cite{LXY192}, some suitable functionals
should be designed and the elaborated co-normal energy estimates will be
involved in analysis due to the variation of density and the interaction
between the density and velocity.Comment: 50 page
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