1,004 research outputs found
Predictive Control for Alleviation of Gust Loads on Very Flexible Aircraft
In this work the dynamics of very flexible aircraft are described by a set of non-linear, multi-disciplinary equations of motion. Primary structural components are represented by a geometrically-exact composite beam model which captures the large dynamic deformations of the aircraft and the interaction between rigid-body and elastic degrees-of-freedom. In addition, an implementation of the unsteady vortex-lattice method capable of handling arbitrary kinematics is used to capture the unsteady, three-dimensional flow-eld around the aircraft as it deforms. Linearization of this coupled nonlinear description, which can in general be about a nonlinear reference state, is performed to yield relatively high-order linear time-invariant state-space models. Subsequent reduction of these models using standard balanced truncation results in low-order models suitable for the synthesis of online, optimization-based control schemes that incorporate actuator constraints. Predictive controllers are synthesized using these reduced-order models and applied to nonlinear simulations of the plant dynamics where they are shown to be superior to equivalent optimal linear controllers (LQR) for problems in which constraints are active
Comparison of predictive scores of symptomatic intracerebral haemorrhage after stroke thrombolysis in a single centre
Peer reviewedPublisher PD
The Predictive Validity of Mathematics Curriculum-Based Measurement on Smarter Balanced Assessment Consortium Mathematics Scores
The purpose of this study was to examine the predicative validity of computation curriculumbased measurement (CBM) on mathematics Smarter Balanced Assessment Consortium scores (SBAC). This study looked at one cohort consisting of 2,741 participants in third, fourth, and fifth grade during the 2017-2018 school year in one school district in Oregon. This study used a hierarchical multiple regression to examine the relationship between CBM and mathematics SBAC. Additionally, this study looked at the extent to which gender, ethnicity, special education status (SPED) and English language learner (ELL) status interacted with CBM scores to predict end-of-year mathematics SBAC scores. The findings of this study indicate that CBM scores predict math SBAC scores in third, fourth, and fifth grade to a modest extent. The findings also indicate that taken together, CBM scores, gender, ethnicity, special education status, and English language learner status predict math SBAC scores to a moderate extent
Can Tc-99m labeled erythrocyte scintigraphy be an alternative non-invasive method to endometriosis diagnosis?
Background: Endometriosis is defined as the implantation of endometrial gland and stroma ectopically outside the uterus. Clinically, it is a hormone dependent benign disease accompanied by pelvic pain and infertility. The aim of this study was to demonstrate the activated implants with 99m-Tc labeled erythrocyte scintigraphy (99mTc-RBCs) in patients with recurrent endometriosis and compare the results with pelvic MRI results.Methods: Patients who were diagnosed histopathologically as endometriosis either with operation and / or therapeutic laparascopy or laparotomy and, were included to present study. Thirty patients, who were diagnosed as recurrence by clinical, and laboratory terms and 10 healthy volunteer (control group) patients were included in the study. Between the second and fifth days of menstruation when the endometriotic lesions were highly activated, radionuclide imaging was performed by 99mTc-RBCs and compared with pelvic MRI findings.Results: In 27 patients out of 30 patients (90%) pathological accumulation of radioactivity foci with 99mTc-RBCs were present. The focal pathological accumulation was significant in 26 patients and moderate in 1 patient. In 22 patients (81.5%) the increased radioactivity accumulation in radionuclide images was concordant with MRI images. Regarding the MRI as reference, the sensitivity of 99mTc-RBCs was determined as 96%, specificity 29%, positive predicitive value 81% and negative predictive value was 66%.Conclusions: Imaging of endometriosis regions with 99m-Tc-RBCs can be an alternative diagnostic procedure for the patients with recurrent endometriosis
Prediction of infectious disease epidemics via weighted density ensembles
Accurate and reliable predictions of infectious disease dynamics can be
valuable to public health organizations that plan interventions to decrease or
prevent disease transmission. A great variety of models have been developed for
this task, using different model structures, covariates, and targets for
prediction. Experience has shown that the performance of these models varies;
some tend to do better or worse in different seasons or at different points
within a season. Ensemble methods combine multiple models to obtain a single
prediction that leverages the strengths of each model. We considered a range of
ensemble methods that each form a predictive density for a target of interest
as a weighted sum of the predictive densities from component models. In the
simplest case, equal weight is assigned to each component model; in the most
complex case, the weights vary with the region, prediction target, week of the
season when the predictions are made, a measure of component model uncertainty,
and recent observations of disease incidence. We applied these methods to
predict measures of influenza season timing and severity in the United States,
both at the national and regional levels, using three component models. We
trained the models on retrospective predictions from 14 seasons (1997/1998 -
2010/2011) and evaluated each model's prospective, out-of-sample performance in
the five subsequent influenza seasons. In this test phase, the ensemble methods
showed overall performance that was similar to the best of the component
models, but offered more consistent performance across seasons than the
component models. Ensemble methods offer the potential to deliver more reliable
predictions to public health decision makers.Comment: 20 pages, 6 figure
Kinetic description of optimal control problems and applications to opinion consensus
In this paper an optimal control problem for a large system of interacting
agents is considered using a kinetic perspective. As a prototype model we
analyze a microscopic model of opinion formation under constraints. For this
problem a Boltzmann-type equation based on a model predictive control
formulation is introduced and discussed. In particular, the receding horizon
strategy permits to embed the minimization of suitable cost functional into
binary particle interactions. The corresponding Fokker-Planck asymptotic limit
is also derived and explicit expressions of stationary solutions are given.
Several numerical results showing the robustness of the present approach are
finally reported.Comment: 25 pages, 18 figure
- …