15,117 research outputs found
Design and evaluation of a robust dynamic neurocontroller for a multivariable aircraft control problem
The design of a dynamic neurocontroller with good robustness properties is presented for a multivariable aircraft control problem. The internal dynamics of the neurocontroller are synthesized by a state estimator feedback loop. The neurocontrol is generated by a multilayer feedforward neural network which is trained through backpropagation to minimize an objective function that is a weighted sum of tracking errors, and control input commands and rates. The neurocontroller exhibits good robustness through stability margins in phase and vehicle output gains. By maintaining performance and stability in the presence of sensor failures in the error loops, the structure of the neurocontroller is also consistent with the classical approach of flight control design
Can correlations drive a band insulator metallic?
We analyze the effects of the on-site Coulomb repulsion U on a band insulator
using dynamical mean field theory (DMFT). We find the surprising result that
the gap is suppressed to zero at a critical Uc1 and remains zero within a
metallic phase. At a larger Uc2 there is a second transition from the metal to
a Mott insulator, in which the gap increases with increasing U. These results
are qualitatively different from Hartree-Fock theory which gives a
monotonically decreasing but non-zero insulating gap for all finite U.Comment: 4 pages, 5 figure
Energy Efficient Service Delivery in Clouds in Compliance with the Kyoto Protocol
Cloud computing is revolutionizing the ICT landscape by providing scalable
and efficient computing resources on demand. The ICT industry - especially data
centers, are responsible for considerable amounts of CO2 emissions and will
very soon be faced with legislative restrictions, such as the Kyoto protocol,
defining caps at different organizational levels (country, industry branch
etc.) A lot has been done around energy efficient data centers, yet there is
very little work done in defining flexible models considering CO2. In this
paper we present a first attempt of modeling data centers in compliance with
the Kyoto protocol. We discuss a novel approach for trading credits for
emission reductions across data centers to comply with their constraints. CO2
caps can be integrated with Service Level Agreements and juxtaposed to other
computing commodities (e.g. computational power, storage), setting a foundation
for implementing next-generation schedulers and pricing models that support
Kyoto-compliant CO2 trading schemes
Aperture Supervision for Monocular Depth Estimation
We present a novel method to train machine learning algorithms to estimate
scene depths from a single image, by using the information provided by a
camera's aperture as supervision. Prior works use a depth sensor's outputs or
images of the same scene from alternate viewpoints as supervision, while our
method instead uses images from the same viewpoint taken with a varying camera
aperture. To enable learning algorithms to use aperture effects as supervision,
we introduce two differentiable aperture rendering functions that use the input
image and predicted depths to simulate the depth-of-field effects caused by
real camera apertures. We train a monocular depth estimation network end-to-end
to predict the scene depths that best explain these finite aperture images as
defocus-blurred renderings of the input all-in-focus image.Comment: To appear at CVPR 2018 (updated to camera ready version
A systematic study on predicting depression using text analytics
Social Networking Sites (SNS) provides online communication among groups but somehow it is affecting the status of mental health. For adolescents with limited social media friends and using internet for communication purposes predicted less depression, whereas non-communication desire reveals more depression and anxiety disorder. Social media posts and comments provide a rich source of text data for academic research. In this paper, we have discussed various text analytical approaches to predict depression among users through the sharing of online ideas over such websites. This paper presents a comprehensive review for predicting depression disorder by various text analytics approaches. This paper also presents the summary of results obtained by some researchers available in literature to predict MajorDepressive Disorder (MDD). In future research, enable self-monitoring of health status of each individuals which may help to increase well-being of an identity.Keywords: Social Networking Sites; Sentiment Analysis; Machine Learning; Support Vector Machine
Effect of volcanic debris on stratospheric ion conductivity
The reduction is reported of stratospheric ion conductivities in the altitude range of 20 to 27 km attributable to the aerosols injected into the stratosphere by the eruption of volcano Nevado Del Ruiz on November 13, 1985. Three balloon experiments were conducted from Hyderabad, India (17.5 N, 78.6 E) carrying a Langmuir probe payload for measuring stratospheric ion conductivities. The first flight took place about 9 months before the volcanic eruption, the second 3 weeks after the eruption and the third about a year later. Lidar observations from Japan, Hawaii and Europe reported detection of aerosol layers in the 18 to 25 km altitude range attributable to the Nevado Del Ruiz volcanic eruption. A comparison of the conductivity profiles shows that the reduction of ion conductivities is: 57.3 percent at 20 km and 31 percent at 25 km. A year after the eruption, conductivities at all heights tended to recover
Knuthian Drawings of Series-Parallel Flowcharts
Inspired by a classic paper by Knuth, we revisit the problem of drawing
flowcharts of loop-free algorithms, that is, degree-three series-parallel
digraphs. Our drawing algorithms show that it is possible to produce Knuthian
drawings of degree-three series-parallel digraphs with good aspect ratios and
small numbers of edge bends.Comment: Full versio
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