954 research outputs found
The prevalence of problem-drinking and other health-related behaviours in a sample of Hong Kong general hospital patients
Author name used in this publication: David ArthurAuthor name used in this publication: Leung Sau FongVersion of RecordPublishe
Buildup of the ring current during periodic loading‐unloading cycles in the magnetotail driven by steady southward interplanetary magnetic field
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95239/1/jgra18825.pd
Detection of Children Abuse by Voice and Audio Classification by Short-Time Fourier Transform Machine Learning implemented on Nvidia Edge GPU device
The safety of children in children home has become an increasing social
concern, and the purpose of this experiment is to use machine learning applied
to detect the scenarios of child abuse to increase the safety of children. This
experiment uses machine learning to classify and recognize a child's voice and
predict whether the current sound made by the child is crying, screaming or
laughing. If a child is found to be crying or screaming, an alert is
immediately sent to the relevant personnel so that they can perceive what the
child may be experiencing in a surveillance blind spot and respond in a timely
manner. Together with a hybrid use of video image classification, the accuracy
of child abuse detection can be significantly increased. This greatly reduces
the likelihood that a child will receive violent abuse in the nursery and
allows personnel to stop an imminent or incipient child abuse incident in time.
The datasets collected from this experiment is entirely from sounds recorded on
site at the children home, including crying, laughing, screaming sound and
background noises. These sound files are transformed into spectrograms using
Short-Time Fourier Transform, and then these image data are imported into a CNN
neural network for classification, and the final trained model can achieve an
accuracy of about 92% for sound detection.Comment: 5 pages, 7 figures, PRAI 202
The prevalence of problem drinking and other health-related behaviours in a sample of Hong Kong general hospital patients
Objective: Little research evidence is available on the prevalence of problem drinking and other health related behaviours in Hong Kong. The purpose of this study was to test the utility, the validity and reliability of the AUDIT, a well-tested and validated screening instrument for alcohol consumption, in the Chinese language and with a sample of Hong Kong hospital patients. The study examined the prevalence of problem-drinkers amongst a sample of general hospital patients and compared this to the prevalence of other health-related behaviours. Method: The AUDIT was translated into Chinese and embedded in a broader lifestyle questionnaire and administered to a convenience sample of 121 general hospital patients in a busy Hong Kong general hospital. Results: 44% of the sample had received no formal education or were educated at the primary level and the respondents felt the people who should be interested in their health were relatives and friends ahead of doctors and nurses. The sample expressed they had a definite weight problem (28%); an eating problem (16%); a smoking problem (22%); a drinking problem (4%) and a fitness problem (23%). The AUDIT proved internally consistent and was able to detect that 44% of the respondents were non-drinkers and that 11 % were drinking at a hazardous or harmful level. Conclusions: The findings encouraged the future use of this Chinese version of the AUDIT in future research and provided useful baseline data for health related behaviours as well as suggesting that Hong Kong health care workers consider seriously their role in working with people and their families in relation to health promotion and education
Dynamic Boundaries in Asymmetric Exclusion Processes
We investigate the dynamics of a one-dimensional asymmetric exclusion process
with Langmuir kinetics and a fluctuating wall. At the left boundary, particles
are injected onto the lattice; from there, the particles hop to the right.
Along the lattice, particles can adsorb or desorb, and the right boundary is
defined by a wall particle. The confining wall particle has intrinsic forward
and backward hopping, a net leftward drift, and cannot desorb. Performing Monte
Carlo simulations and using a moving-frame finite segment approach coupled to
mean field theory, we find the parameter regimes in which the wall acquires a
steady state position. In other regimes, the wall will either drift to the left
and fall off the lattice at the injection site, or drift indefinitely to the
right. Our results are discussed in the context of non-equilibrium phases of
the system, fluctuating boundary layers, and particle densities in the lab
frame versus the frame of the fluctuating wall.Comment: 13 page
Plasmasphere Modeling with Ring Current Heating
Coulomb collisions between ring current ions and the thermal plasma in the plasmasphere will heat the plasmaspheric electrons and ions. During a storm such heating would lead to significant changes in the temperature and density of the thermal plasma. This was modeled using a time- dependent, one-stream hydrodynamic model for plasmaspheric flows, in which the model flux tube is connected to the ionosphere. The model simultaneously solves the coupled continuity, momentum, and energy equations of a two-ion (H(+) and O(+) quasineutral, currentless plasma. Heating rates due to collisions with ring current ions were calculated along the field line using a kinetic ring current model. First, diurnally reproducible results were found assuming only photoelectron heating of the thermal electrons. Then results were found with heating of the H(+) ions by the ring current during the recovery phase of a magnetic storm
Mathematical models for vulnerable plaques
A plaque is an accumulation and swelling in the artery walls and typically consists of cells, cell debris, lipids, calcium deposits and fibrous connective tissue. A person is likely to have many plaques inside his/her body even if they are healthy. However plaques may become "vulnerable", "high-risk" or "thrombosis-prone" if the person engages in a high-fat diet and does not exercise regularly.
In this study group, we proposed two mathematical models to describe plaque growth and rupture.
The first model is a mechanical one that approximately treats the plaque as an inflating elastic balloon. In this model, the pressure inside the core increases and then decreases suggesting that plaque stabilization and prevention of rupture is possible.
The second model is a biochemical one that focuses on the role of MMPs in degrading the fibrous plaque cap. The cap stress, MMP concentration, plaque volume and cap thickness are coupled together in a system of phenomenological equations. The equations always predict an eventual rupture since the volume, stresses and MMP concentrations generally grow without bound. The main weakness of the model is that many of the important parameters that control the behavior of the plaque are unknown.
The two simple models suggested by this group could serve as a springboard for more realistic theoretical studies. But most importantly, we hope they will motivate more experimental work to quantify some of the important mechanical and biochemical properties of vulnerable plaques
Anisotropic diffusion in continuum relaxation of stepped crystal surfaces
We study the continuum limit in 2+1 dimensions of nanoscale anisotropic
diffusion processes on crystal surfaces relaxing to become flat below
roughening. Our main result is a continuum law for the surface flux in terms of
a new continuum-scale tensor mobility. The starting point is the Burton,
Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps
whose motion drives surface evolution. Our derivation is based on the
separation of local space variables into fast and slow. The model includes: (i)
anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps;
(ii) diffusion of atoms along step edges; and (iii) attachment-detachment of
atoms at step edges. We derive a parabolic fourth-order, fully nonlinear
partial differential equation (PDE) for the continuum surface height profile.
An ingredient of this PDE is the surface mobility for the adatom flux, which is
a nontrivial extension of the tensor mobility for isotropic terrace diffusion
derived previously by Margetis and Kohn. Approximate, separable solutions of
the PDE are discussed.Comment: 14 pages, 1 figur
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