scholarly journals COVID-19 Waves: Variant Dynamics and Control

2021 ◽  
Author(s):  
Abhishek Dutta
Keyword(s):  
Feedback Control ◽  
Vaccination Strategy ◽  
Coupled Dynamics ◽  
The Us ◽  
Dynamics And Control ◽  
Novel Coronavirus ◽  
And Control

Abstract The COVID-19 variants driven waves continue to try to nullify the success we achieved through efficacious vaccines, test and quarantine and social restrictions. This paper models the two major variants driven waves by two sets of susceptible-infected-quarantined-recovered-vaccinated-deceased coupled dynamics that is modulated by the three main interventions: vaccination, quarantine and restrictions. This SI2Q2R2VD system is used to demonstrate that the second major novel coronavirus wave in the US is caused by the delta variant and the corresponding rapid surge in infectious cases is driven by the unvaccinated pool of the populace. Next, a feedback control based planned vaccination strategy is derived and is shown to be able to suppress the surge in infections effectively.

A multigroup model for cholera dynamics and control

2015 ◽  
Vol 09 (01) ◽  
pp. 1650001 ◽  
Author(s):  
Drew Posny ◽  
Chairat Modnak ◽  
Jin Wang
Keyword(s):  
Reproduction Number ◽  
Vaccination Strategy ◽  
Sharp Threshold ◽  
Indirect Transmission ◽  
Dynamics And Control ◽  
Simulation Results ◽  
Transmission Pathways ◽  
And Control ◽  
Control Study ◽  
The Basic Reproduction Number

We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.

Dynamics and control of resistive wall modes with magnetic feedback control coils: experiment and theory

2005 ◽  
Vol 45 (4) ◽  
pp. 285-293 ◽  
Author(s):  
M.E Mauel ◽  
J Bialek ◽  
A.H Boozer ◽  
C Cates ◽  
R James ◽  
...  
Keyword(s):  
Feedback Control ◽  
Dynamics And Control ◽  
Resistive Wall ◽  
And Control ◽  
Resistive Wall Modes

Active Stabilization of a Two-Satellite Tether in Elliptic Orbits Using Coulomb Forces

2011 ◽  
Vol 110-116 ◽  
pp. 4537-4543
Author(s):  
Hao Zhang ◽  
Yu Shan Zhao ◽  
Peng Shi
Keyword(s):  
Feedback Control ◽  
Hybrid Control ◽  
Control Law ◽  
State Matrix ◽  
Periodic Control ◽  
Elliptic Orbits ◽  
Active Stabilization ◽  
Dynamics And Control ◽  
Constant State ◽  
And Control

This paper investigates the dynamics and control of a charged two-craft tether formation in elliptical orbit. Due to the fact that the inter-spacecraft Coulomb forces are not sufficient to stabilize the tether, a method of hybrid control is proposed which uses conventional thrusts and Coulomb forces. A feedback control law is developed which could asymptotically stabilize the tether size and attitude while mitigating plume impingement issues. The equations governing this system are periodic in time, thus a feedback control using constant gains can not work. A periodic control law is suggested basing on Floquet theory. The control law consists of two main parts. First Floquet transformation is utilized to transform the system into a new linear system with a constant state matrix but a periodic control matrix. Then a feedback control is used to stabilize the new system. Numerical examples are provided to demonstrate the performance of the control law.

scholarly journals Forecasting the Epidemiological Impact of Coronavirus Disease (COVID-19): Pre-vaccination Era

2021 ◽  
Author(s):  
Saheed Oladele Amusat
Keyword(s):  
Data Analysis ◽  
Prevention And Control ◽  
Historical Data ◽  
Secondary Data ◽  
The Novel ◽  
Intervention Method ◽  
The Us ◽  
Epidemiological Impact ◽  
Novel Coronavirus ◽  
And Control

Background: During this pandemic, many studies have been published on the virology, diagnosis, prevention, and control of the novel coronavirus. However, fewer studies are currently available on the quantitative future epidemiological impacts. Therefore, the purpose of this study is to forecast the COVID-19 morbidities and associated-mortalities among the top 20 countries with the highest number of confirmed COVID-19 cases globally prior to vaccination intervention. Method: We conducted a secondary data analysis of the prospective geographic distribution of COVID-19 cases data worldwide as of 10 April 2020. The historical data was forecasted using Exponential-Smoothing to detect seasonality patterns and confidence intervals surrounding each predicted value in which 95 percent of the future points are expected to fall based on the forecast. Results: The total mean forecasted cases and deaths were 99,823 and 8,801. Interestingly, the US has the highest forecasted cases, deaths, and percentage cases-deaths ratio of 45,338, 2 358, and 5.20% respectively. China has the lowest cases, deaths, and percentage cases-deaths ratio -267, -2, and 0.75% respectively. In addition, France has the highest forecasted percentage cases-deaths ratio of 26.40% with forecasted cases, and deaths of 6,246, and 1,649 respectively. Conclusion Our study revealed the possibility of higher COVID-19 morbidities and associated-mortalities worldwide.

Dynamics and Control of a 4C Mechanism

2000 ◽  
Author(s):  
Michael S. Hanchak ◽  
Reza Kashani ◽  
Andrew P. Murray
Keyword(s):  
Feedback Control ◽  
Realistic Model ◽  
Lagrangian Formulation ◽  
Feed Forward ◽  
Control Scheme ◽  
Dynamics And Control ◽  
Trajectory Following ◽  
Spatial Trajectory ◽  
And Control ◽  
Two Degree Of Freedom

Abstract This paper presents the dynamics and control of a two degree-of-freedom 4C mechanism synthesized to guide a body through a spatial trajectory. A CC dyad, a coupling of fixed and moving cylindric or C joints, can be designed to reach five spatial positions. Two seperate CC dyads designed to reach three positions are rigidly connected between the two moving C joints defining the 4C mechanism presented. Constrained Lagrangian formulation was used to determine the actuator forcing for a desired trajectory of the input joint (both displacement and rotation). The mechansim was implemented and controlled in ADAMS© software using a feed-forward, feedback control scheme. This technique produced a realistic model with excellent trajectory following characteristics.

Dynamics and Control of Supercavitating Vehicles

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Guojian Lin ◽  
Balakumar Balachandran ◽  
Eyad H. Abed
Keyword(s):  
Feedback Control ◽  
Limit Cycle ◽  
Switching Control ◽  
State Feedback Control ◽  
Region Of Attraction ◽  
Supercavitating Vehicles ◽  
Control Scheme ◽  
Loop Dynamics ◽  
Dynamics And Control ◽  
And Control

Analytical and numerical investigations into the dynamics and control of dive-plane dynamics of supercavitating vehicles are presented. Dominant nonlinearities associated with planing forces are taken into account in the model. Two controllers are proposed to realize stable inner-loop dynamics, a linear state feedback control scheme and a switching control scheme. Through numerical simulations and estimation of the region of attraction, it is shown that effective feedback schemes can be constructed. In comparison to existing control schemes, the feedback schemes proposed in this work can stabilize a supercavitating vehicle with a large region of attraction around the trim condition instead of just stabilization around the limit cycle motion. In particular, the achieved stability is robust to modeling errors in the planing force. This robustness is especially important for supercavitating vehicles because the underlying planing force physics is complicated and not yet fully understood. Compared to the linear feedback control scheme, the switching control scheme is seen to increase the region of attraction with reduced control effort, which can be useful for avoiding saturation in magnitude. Analytical tools, including the describing function method and the circle criterion, are applied to facilitate understanding of the closed-loop system dynamics and assist in the controller design. This work provides a basis for interpreting the tail-slap phenomenon of a supercavitating body as a limit cycle motion and for developing control methods to achieve stable inner-loop dynamics in the full model.

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