33,801 research outputs found
Combining Stream Mining and Neural Networks for Short Term Delay Prediction
The systems monitoring the location of public transport vehicles rely on
wireless transmission. The location readings from GPS-based devices are
received with some latency caused by periodical data transmission and temporal
problems preventing data transmission. This negatively affects identification
of delayed vehicles. The primary objective of the work is to propose short term
hybrid delay prediction method. The method relies on adaptive selection of
Hoeffding trees, being stream classification technique and multilayer
perceptrons. In this way, the hybrid method proposed in this study provides
anytime predictions and eliminates the need to collect extensive training data
before any predictions can be made. Moreover, the use of neural networks
increases the accuracy of the predictions compared with the use of Hoeffding
trees only
Automated polyp detection in colon capsule endoscopy
Colorectal polyps are important precursors to colon cancer, a major health
problem. Colon capsule endoscopy (CCE) is a safe and minimally invasive
examination procedure, in which the images of the intestine are obtained via
digital cameras on board of a small capsule ingested by a patient. The video
sequence is then analyzed for the presence of polyps. We propose an algorithm
that relieves the labor of a human operator analyzing the frames in the video
sequence. The algorithm acts as a binary classifier, which labels the frame as
either containing polyps or not, based on the geometrical analysis and the
texture content of the frame. The geometrical analysis is based on a
segmentation of an image with the help of a mid-pass filter. The features
extracted by the segmentation procedure are classified according to an
assumption that the polyps are characterized as protrusions that are mostly
round in shape. Thus, we use a best fit ball radius as a decision parameter of
a binary classifier. We present a statistical study of the performance of our
approach on a data set containing over 18,900 frames from the endoscopic video
sequences of five adult patients. The algorithm demonstrates a solid
performance, achieving 47% sensitivity per frame and over 81% sensitivity per
polyp at a specificity level of 90%. On average, with a video sequence length
of 3747 frames, only 367 false positive frames need to be inspected by a human
operator.Comment: 16 pages, 9 figures, 4 table
Influence of local geology on earthquake ground motion
As a simplified approach for estimating theoretically the influence of local subsoils upon the ground motion during an earthquake, the problem of an idealized layered system subjected to vertically incident plane body waves was studied. Both the technique of steady-state analysis and the technique of transient analysis have been used to analyze the problem.
In the steady-state analysis, a recursion formula has been derived for obtaining the response of a layered system to sinusoidally steady-state input. Several conclusions are drawn concerning the nature of the amplification spectrum of a nonviscous layered system having its layer stiffnesses increasing with depth. Numerical examples are given to demonstrate the effect of layer parameters on the amplification spectrum of a layered system.
In the transient analysis, two modified shear beam models have been established for obtaining approximately the response of a layered system to earthquake -like excitation. The method of continuous modal analysis was adopted for approximate analysis of the models, with energy dissipation in the layers, if any, taken into account. Numerical examples are given to demonstrate the accuracy of the models and the effect of a layered system in modifying the input motion.
Conditions are established, under which the theory is applicable to predict the influence of local subsoils on the ground motion during an earthquake. To demonstrate the applicability of the models to actual cases, three examples of actually recorded earthquake events are examined. It is concluded that significant modification of the incoming seismic waves, as predicted by the theory, is likely to occur in well defined soft subsoils during an earthquake, provided that certain conditions concerning the nature of the incoming seismic waves are satisfied
Singularity-matching peaks in superconducting single-electron transistor
We report the experimental observation of the recently predicted peaks on the
I-V curve of the superconducting single-electron transistor at relatively high
temperatures. The peaks are due to the matching of singularities in the
quasiparticle density of states in two electrodes of a tunnel junction. The
energy shift due to Coulomb blockade provides the matching at finite voltage.Comment: 11 pages (RevTeX), 3 figure
A note on the steady-state response of an elastic half-space
With reference to the influence of local geology on earthquake ground motions, a more complete analytical formulation is made of the well-known problem of a horizontally stratified, linearly-elastic half-space subjected to vertically traveling, sinusoidal, plane waves. A more general interpretation of a result of Kanai is given, and a recursion formula is derived for computing amplification spectra. Some special properties of the system are pointed out and numerical examples are given
Infrared probe of the anomalous magnetotransport of highly oriented pyrolytic graphite in the extreme quantum limit
We present a systematic investigation of the magnetoreflectance of highly
oriented pyrolytic graphite in magnetic field B up to 18 T . From these
measurements, we report the determination of lifetimes tau associated with the
lowest Landau levels in the quantum limit. We find a linear field dependence
for inverse lifetime 1/tau(B) of the lowest Landau levels, which is consistent
with the hypothesis of a three-dimensional (3D) to 1D crossover in an
anisotropic 3D metal in the quantum limit. This enigmatic result uncovers the
origin of the anomalous linear in-plane magnetoresistance observed both in bulk
graphite and recently in mesoscopic graphite samples
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Latanoprost with high precision, piezo-print microdose delivery for IOP lowering: clinical results of the PG21 study of 0.4 µg daily microdose.
Background:Topical high-precision piezo-print delivery of microdoses of latanoprost achieved significant IOP reduction consistent with the eyedropper effect but with a 75% reduced exposure to drugs and preservatives. Prostaglandin analogs are a mainstay glaucoma therapy. However, conventional eyedroppers deliver 30-50 µL drops that greatly exceed the physiologic 7-µL ocular tear film capacity. Eyedropper overdosing floods the eye with excess drug compounds and preservatives, resulting in ocular surface toxicity, periorbitopathy, and other well-characterized ocular side effects. Piezoelectric high-precision microdosing provides targeted delivery that can reduce exposure to both drug and preservatives compared to conventional eyedropper delivery, with the potential to deliver similar biologic effect. Methods:Both eyes (N=60) of 30 healthy volunteers received single 8-µL microdoses of 0.005% latanoprost (0.4 µg; µRx-latanoprost) on the morning of Days 1 and 2 using a high-precision, piezo-print horizontal delivery system. Diurnal IOP was measured before and 2 days after microdosing. Main efficacy outcomes were diurnal IOP change after µRx-latanoprost microdosing and accurate microdosing success rates, and the primary safety outcome was adverse event (AE) incidence. Results:µRx-latanoprost reduced baseline IOP by 26% and 30% at 1 and 2 days postadministration, respectively. Successful topical dosing was achieved in 100% of technician-assisted deliveries. All patients successfully self-administered microdoses after receiving training. Microdose administration was well tolerated and did not result in any AEs. Conclusion:Microdosing of 0.4 µg of µRx-latanoprost achieved significant IOP reduction. Lower ocular exposure with topical prostaglandin analog microdosing can enable new therapeutic opportunities for optimizing glaucoma treatment. Microdosing may also be beneficial in reducing ocular side effects associated with excessive drug product and preservatives often used to treat chronic ocular diseases such as glaucoma
Calculation of surface motions of a layered half-space
A new method is presented for computing the transient response of a set of horizontally stratified, linearly elastic layers overlying a uniform half-space and excited by vertically incident, transient plane waves. In addition, a simple approximate method of satisfactory accuracy is developed that reduces the computing time required. Calculated responses are compared with motions recorded under Union Bay in Seattle to evaluate the agreement between recorded and calculated motions
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