703 research outputs found
A systematic literature review of cloud computing in eHealth
Cloud computing in eHealth is an emerging area for only few years. There
needs to identify the state of the art and pinpoint challenges and possible
directions for researchers and applications developers. Based on this need, we
have conducted a systematic review of cloud computing in eHealth. We searched
ACM Digital Library, IEEE Xplore, Inspec, ISI Web of Science and Springer as
well as relevant open-access journals for relevant articles. A total of 237
studies were first searched, of which 44 papers met the Include Criteria. The
studies identified three types of studied areas about cloud computing in
eHealth, namely (1) cloud-based eHealth framework design (n=13); (2)
applications of cloud computing (n=17); and (3) security or privacy control
mechanisms of healthcare data in the cloud (n=14). Most of the studies in the
review were about designs and concept-proof. Only very few studies have
evaluated their research in the real world, which may indicate that the
application of cloud computing in eHealth is still very immature. However, our
presented review could pinpoint that a hybrid cloud platform with mixed access
control and security protection mechanisms will be a main research area for
developing citizen centred home-based healthcare applications
Asymptotic normality and consistency of a two-stage generalized least squares estimator in the growth curve model
Let \mathbf{Y}=\mathbf{X}\bolds{\Theta}\mathbf{Z}'+\bolds{\mathcal {E}} be
the growth curve model with \bolds{\mathcal{E}} distributed with mean
and covariance \mathbf{I}_n\otimes\bolds{\Sigma}, where
\bolds{\Theta}, \bolds{\Sigma} are unknown matrices of parameters and
, are known matrices. For the estimable parametric
transformation of the form \bolds
{\gamma}=\mathbf{C}\bolds{\Theta}\mathbf{D}' with given and
, the two-stage generalized least-squares estimator \hat{\bolds
\gamma}(\mathbf{Y}) defined in (7) converges in probability to \bolds\gamma
as the sample size tends to infinity and, further,
\sqrt{n}[\hat{\bolds{\gamma}}(\mathbf{Y})-\bolds {\gamma}] converges in
distribution to the multivariate normal distribution \ma
thcal{N}(\mathbf{0},(\mathbf{C}\mathbf{R}^{-1}\mathbf{C}')\otimes(\mat
hbf{D}(\mathbf{Z}'\bolds{\Sigma}^{-1}\mathbf{Z})^{-1}\mathbf{D}')) under the
condition that for some
positive definite matrix . Moreover, the unbiased and invariant
quadratic estimator \hat{\bolds{\Sigma}}(\mathbf{Y}) defined in (6) is also
proved to be consistent with the second-order parameter matrix
\bolds{\Sigma}.Comment: Published in at http://dx.doi.org/10.3150/08-BEJ128 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
Estimation for an additive growth curve model with orthogonal design matrices
An additive growth curve model with orthogonal design matrices is proposed in
which observations may have different profile forms. The proposed model allows
us to fit data and then estimate parameters in a more parsimonious way than the
traditional growth curve model. Two-stage generalized least-squares estimators
for the regression coefficients are derived where a quadratic estimator for the
covariance of observations is taken as the first-stage estimator. Consistency,
asymptotic normality and asymptotic independence of these estimators are
investigated. Simulation studies and a numerical example are given to
illustrate the efficiency and parsimony of the proposed model for model
specifications in the sense of minimizing Akaike's information criterion (AIC).Comment: Published in at http://dx.doi.org/10.3150/10-BEJ315 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
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Printable 2d Material Optoelectronics and Photonics
Graphene and structurally similar 2-dimensional (2d) materials such as transition metal dichalcogenides (TMDs) and black phosphorus (BP) hold enormous potential for the next generation optoelectronics and photonics. Pairing 2d materials with printing is an emerging cost-effective large-scale device fabrication strategy. However, the current inks are far from ideal to support reproducible device fabrication. In addition, the instability of BP in ambient limits its applications.
In this thesis, I present formulation of 2d material inks for inkjet printing for optoelectronic and photonic applications. To begin with, I produce mono- and few-layer 2d material flakes via ultrasonic assisted liquid phase exfoliation. This allows one-step formulation of a polymer stabilised graphene ink. For TMDs and BP, I design a binary solvent carrier for binder-free ink formulation. I show that these 2d material inks have optimal fluidic properties, drying dynamics and interaction with substrates for spatially uniform, highly controllable and print-to-print consistent large-scale printing on untreated substrates. In particular, the rapid ink drying at low temperatures leads to minimal oxidation of BP during ambient printing; the printed BP with passivation retains a stability over one month. On this basis, the printed graphene is employed as active sensing layer in CMOS integrated humidity sensors and as counter-electrodes in dye-sensitised solar cells, while the printed TMDs and BP are used to develop nonlinear photonic devices (i.e. saturable absorbers for femtosecond pulsed laser generation) and visible to near-infrared photodetectors (e.g. MoS and BP/graphene/silicon hybrid photodetectors).
Beyond inkjet printing, I present an ink formulation of commercial graphene nanoplatelets for roll-to-roll flexographic press (100 m min printing speed). This allows hundreds of conductive electronic circuits to be printed in a minute for capacitive touchpads.
Though I investigate only graphene, TMDs and BP, the ink formulation strategies can be effortlessly transferred to other 2d materials such as boron nitride, MXenes and mica. In addition to the demonstrated applications, printing of 2d materials can be potentially exploited to fabricate devices such as transistors, light emitters, energy storage conversion, and biosensors. This significantly expands the prospect of printable 2d material optoelectronics and photonics.China Scholarship Council, Cambridge Overseas Trust, and St John’s College
A pathway analysis of genome-wide association study highlights novel type 2 diabetes risk pathways.
Genome-wide association studies (GWAS) have been widely used to identify common type 2 diabetes (T2D) variants. However, the known variants just explain less than 20% of the overall estimated genetic contribution to T2D. Pathway-based methods have been applied into T2D GWAS datasets to investigate the biological mechanisms and reported some novel T2D risk pathways. However, few pathways were shared in these studies. Here, we performed a pathway analysis using the summary results from a large-scale meta-analysis of T2D GWAS to investigate more genetic signals in T2D. Here, we selected PLNK and VEGAS to perform the gene-based test and WebGestalt to perform the pathway-based test. We identified 8 shared KEGG pathways after correction for multiple tests in both methods. We confirm previous findings, and highlight some new T2D risk pathways. We believe that our results may be helpful to study the genetic mechanisms of T2D
FPGA-based Digital Baseband Transmission System Performance Tester Research and Design
Communication System Transmission Performance Tester, as a digital communication system design and testing equipment, plays an important role in the construction and daily maintenance of the communication system. The paper presents a kind of tester, which is designed using Cyclone IV FPGA (Field Programmable Gata Array) and VHDL (Very High Speed Integrated Circuits Hardware Description Language). According to the features in the eye diagram, the system performance can intuitively and qualitatively evaluated. The results prove that the system accurately displayed the eye diagram, thereby reflected the performance of the baseband transmission system truthfull
Simulation analysis of crack cause of concrete overflow dam for Hadashan Hydro Project by 3-D FEM
AbstractThis paper is mainly to study the cracking reasons for concrete overflow dam of Hadashan Hydro Project. The three-dimensional finite element method (3-D FEM) is developed to simulation analysis the temperature and thermal stress distribution in the concrete overflow dam during the construction period. The results show that the crack of the concrete overflow dam is temperature crack, mainly due to the combined action of the internal thermal gradient and the external restraints; and dramatic changes in ambient temperature exacerbate cracking of early-age concrete. Finally, the results are applied to provide some references for the construction in the related fields
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