A Cellular Automata Model for Dynamics and Control of Cardiac Arrhythmias

2020 ◽  
Author(s):  
Danny Gallenberger ◽  
Min Xiong ◽  
Tony Z. Zhuang ◽  
Kai Sun ◽  
Elena G. Tolkacheva ◽  
...  
Keyword(s):  
Cellular Automata ◽  
Cardiac Arrhythmias ◽  
Control Method ◽  
Sudden Cardiac Arrest ◽  
Significant Proportion ◽  
The United States ◽  
Effective Control ◽  
Dynamics And Control ◽  
Ca Model ◽  
And Control

Abstract As a leading cause of death in 325,000 adults per year in the United States, a significant proportion of sudden cardiac arrest (SCA) result from arrhythmias. To better understand the onset of arrhythmias and its potential treatment with more rapid and effective control approaches, a two-dimensional 50 × 50 cellular automata (CA) model is used in this study to illustrate the propagation of electrical waves across its tissue, and a constant diastolic interval (DI) control mechanism is adopted to help stabilize and prevent cardiac arrhythmias. Simulations of various scenarios including normal conduction and spiral waves in the presence of scar, normal conduction and alternans under control conditions are shown. The results validate that the CA model and constant DI control method are very efficient and effective in the study of dynamics and control of cardiac arrhythmias.

scholarly journals Assessing the Dynamics and Control of Droplet- and Aerosol-Transmitted Influenza Using an Indoor Positioning System

2017 ◽  
Author(s):  
Timo Smieszek ◽  
Gianrocco Lazzari ◽  
Marcel Salathé
Keyword(s):  
Wireless Sensors ◽  
Public Spaces ◽  
Mitigation Strategies ◽  
Effective Control ◽  
Positioning System ◽  
Close Physical Proximity ◽  
Close Proximity ◽  
Dynamics And Control ◽  
And Control ◽  
Indoor Positioning System

ABSTRACTThere is increasing evidence that aerosol transmission is a major contributor to the spread of influenza. Despite this, virtually all studies assessing the dynamics and control of influenza assume that it is transmitted solely through direct contact and large droplets, requiring close physical proximity. Here, we use wireless sensors to measure simultaneously both the location and close proximity contacts in the population of a US high school. This dataset, highly resolved in space and time, allows us to model both droplet and aerosol transmission either in isolation or in combination. In particular, it allows us to computationally assess the effectiveness of overlooked mitigation strategies such as improved ventilation that are available in the case of aerosol transmission. While the effects of the type of transmission on disease outbreak dynamics appear to be weak, we find that good ventilation could be as effective in mitigating outbreaks as vaccinating the majority of the population. In simulations using empirical transmission levels observed in households, we find that bringing ventilation to recommended levels has the same mitigating effect as a vaccination coverage of 50% to 60%. Our results therefore suggest that improvements of ventilation in public spaces could be an important and easy-to-implement strategy supplementing vaccination efforts for effective control of influenza spread.

Abstract 11269: Recombinant Soluble Thrombomodulin in Prolonged Porcine Cardiac Arrest

Circulation ◽  
2021 ◽  
Vol 144 (Suppl_2) ◽  
Author(s):  
Boya Zhang ◽  
Brendan McCracken ◽  
Danielle Leander ◽  
Carmen Colmenero ◽  
Nicholas Greer ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Sudden Cardiac Arrest ◽  
The United States ◽  
Hypercoagulable State ◽  
Soluble Thrombomodulin ◽  
Consumptive Coagulopathy ◽  
Antithrombotic Effects ◽  
Potential Contributor ◽  
Ca Model ◽  
Coagulation And Fibrinolysis

Introduction: Sudden Cardiac Arrest (CA) affects more than 400,000 people per year in the United States. Although a third of these patients survive to hospital admission, another 60-70% go on to die due to failed recovery of vital organ function. Microvascular thrombosis has been suggested as a potential contributor to prolonged organ dysfunction, but no antithrombotic therapies have been shown to be beneficial and coagulofibrinolytic abnormalities in prolonged CA remain poorly understood. Objectives: To establish key biomarkers of porcine coagulation and fibrinolysis in the setting of prolonged CA and cardiopulmonary resuscitation (CPR) and test the ability of ART-123 (recombinant human thrombomodulin alpha) to reverse these abnormalities. Methods: 15 pigs (n=5 per group) underwent 8 minutes of no-flow CA followed by 50 minutes of mechanical CPR. Animals were randomized to receive saline or ART-123 (~1mg/kg) pre-arrest (5 minutes prior to ventricular fibrillation) or post-arrest (2 minutes after initiation of CPR). Results: Robust and ongoing activation of coagulation and fibrinolysis were detected throughout the resuscitation. After 50 minutes of CPR, plasma tests suggested consumptive coagulopathy, while whole blood testing (thromboelastography) indicated a persistent hypercoagulable state. ART-123 had a clear anticoagulant effect irrespective of timing (TAT complexes 381±25 vs. 238±18 vs. 226±12, p<0.01, and d-dimer 4.86±0.54 vs. 2.39±0.2 vs. 2.46±0.21 for vehicle, pre-arrest, post-arrest, p = 0.05). A pro-fibrinolytic effect was also observed, but only when the drug was given before no-flow, with a significant increase in levels of free endogenous tPA (1.2±0.12 vs. 3.29±0.29 vs. 1.72±0.3, p < 0.001) and corresponding suppression of free PAI-1 (0.59±0.15 vs. 0.14±0.01 vs. 0.41±0.09, p < 0.001). Conclusion: Our porcine CA model provides an excellent platform for evaluating antithrombotic interventions. Plasma testing after prolonged CA/CPR suggests consumptive coagulopathy, although TEG indicates a persistent hypercoagulable state. ART-123 given before no-flow or just after CPR demonstrates antithrombotic effects, although the specific modes of action depending on the timing of administration.

scholarly journals Dynamics of bed bug infestations and control under disclosure policies

2019 ◽  
Vol 116 (13) ◽  
pp. 6473-6481 ◽  
Author(s):  
Sherrie Xie ◽  
Alison L. Hill ◽  
Chris R. Rehmann ◽  
Michael Z. Levy
Keyword(s):  
Cost Benefit ◽  
Control Policy ◽  
Spillover Effects ◽  
The United States ◽  
Effective Control ◽  
Bed Bugs ◽  
Bed Bug ◽  
Highly Nonlinear ◽  
Public Health Practitioners ◽  
And Control

Bed bugs have reemerged in the United States and worldwide over recent decades, presenting a major challenge to both public health practitioners and housing authorities. A number of municipalities have proposed or initiated policies to stem the bed bug epidemic, but little guidance is available to evaluate them. One contentious policy is disclosure, whereby landlords are obligated to notify potential tenants of current or prior bed bug infestations. Aimed to protect tenants from leasing an infested rental unit, disclosure also creates a kind of quarantine, partially and temporarily removing infested units from the market. Here, we develop a mathematical model for the spread of bed bugs in a generalized rental market, calibrate it to parameters of bed bug dispersion and housing turnover, and use it to evaluate the costs and benefits of disclosure policies to landlords. We find disclosure to be an effective control policy to curb infestation prevalence. Over the short term (within 5 years), disclosure policies result in modest increases in cost to landlords, while over the long term, reductions of infestation prevalence lead, on average, to savings. These results are insensitive to different assumptions regarding the prevalence of infestation, rate of introduction of bed bugs from other municipalities, and the strength of the quarantine effect created by disclosure. Beyond its application to bed bugs, our model offers a framework to evaluate policies to curtail the spread of household pests and is appropriate for systems in which spillover effects result in highly nonlinear cost–benefit relationships.

Dynamics and control of a 6-DOF space robot with flexible panels

2016 ◽  
Vol 231 (6) ◽  
pp. 1022-1034 ◽  
Author(s):  
Yu Zhang-Wei ◽  
Liu Xiao-Feng ◽  
Li Hai-Quan ◽  
Cai Guo-Ping
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Torque Control ◽  
Space Robot ◽  
Velocity Variation ◽  
Variation Principle ◽  
Dynamics Modeling ◽  
Dynamics And Control ◽  
Flexible Panels ◽  
And Control

With the development of space exploration, researches on space robot will cause more attentions. However, most existing researches about dynamics and control of space robot concern planar problem, and the effect of flexible panel on dynamics of the system is not considered. In this article, dynamics modeling and active control of a 6-DOF space robot with flexible panels are investigated. Dynamic model of the system is established based on the Jourdain's velocity variation principle and the single direction recursive construction method. The computed torque control method is used to design point-to-point active controller of the space robot. The validity of the dynamic model is verified through the comparison with ADAMS software; the effects of panel flexibility on the system performance and the active controller design are studied in detail. Simulation results indicate that the proposed model is effective to describe the dynamics of space robot; panel flexibility has large influence on the dynamic behavior of space robot; the designed controller can effectively make the robot reach a specified position and the elastic vibration of the panels may be suppressed simultaneously.

Dynamics and Control of a Helicopter Carrying a Payload Using a Cable-Suspended Robot

2005 ◽  
Author(s):  
So-Ryeok Oh ◽  
Ji-Chul Ryu ◽  
Sunil K. Agrawal
Keyword(s):  
Control Method ◽  
Dual System ◽  
Robust Controller ◽  
Robot System ◽  
Control Approach ◽  
Cable Robot ◽  
Dynamics And Control ◽  
Position And Orientation ◽  
And Control ◽  
Scale Control

This paper presents a study of the dynamics and control of a helicopter carrying a payload through a cable-suspended robot. The helicopter can perform gross motion, while the cable suspended robot underneath the helicopter can modulate a platform in position and orientation. Due to the under-actuated nature of the helicopter, the operation of this dual system consisting of the helicopter and the cable robot is challenging. We propose here a two time scale control method, which makes it possible to control the helicopter and the cable robot independently. In addition, this method provides an effective estimation on the bound of the motion of the helicopter. Therefore, even in the case where the helicopter motion is unknown, the cable robot can be stabilized by implementing a robust controller. Simulation results of the dual system show that the proposed control approach is effective for such a helicopter-robot system.

Theoretical and Experimental Investigation of Elevator Cable Dynamics and Control

2005 ◽  
Vol 128 (1) ◽  
pp. 66-78 ◽  
Author(s):  
W. D. Zhu ◽  
Y. Chen
Keyword(s):  
Control Method ◽  
Upward Movement ◽  
High Rise ◽  
Cable Dynamics ◽  
Theoretical Predictions ◽  
Dynamics And Control ◽  
And Control ◽  
Elevator Cable ◽  
Parameter Estimation Techniques ◽  
Good Agreement

The vibratory energy of a moving cable in an elevator increases in general during upward movement. A control method is presented to dissipate the energy associated with the lateral vibration of the cable. A novel experimental method is developed to validate the theoretical predictions for the uncontrolled and controlled lateral responses of a moving cable in a high-rise elevator. This includes the design and fabrication of a scaled elevator, experimental setup, and development of measurement and parameter estimation techniques. Experimental results show good agreement with the theoretical predictions.

On Nonlinear Dynamics and Control of an Inverted Flexible Pendulum System With Chaos

2019 ◽  
Author(s):  
Hartiny Kahar ◽  
Dirk Söffker
Keyword(s):  
Control Method ◽  
Impulsive Control ◽  
Chaotic Behavior ◽  
Energy Content ◽  
Dynamical Behavior ◽  
Pendulum System ◽  
Time Frequency ◽  
Dynamics And Control ◽  
Specific Frequency ◽  
And Control

Abstract In this paper, the dynamical behavior of a nonlinear mechanical system is considered, namely an inverted flexible pendulum excited in its base by a cart driven by a motor. In this experimental procedure, the chaotic motion of the pendulum tip was identified, in combination with a specific range of parameters. Time-frequency energy analysis is performed to be used for modeling the transition between the equilibria of the chaotic systems. Controlling the chaotic behavior of the system is realized using impulsive control method, where additive impulses are injected into the system, designed with specific impulses energy content at a specific frequency band. The experimental results are presented and discussed in detail, concentrating on how the designed impulses have to be injected to affect the system, specifically the transition between states of equilibria. The results from this experimental modeling procedure show that both additive impulse design and frequency filtering of the injected additive impulses are able to stimulate the equilibrium shift and therefore to control the chaotic behavior of the system.

A Reduced Order Model for Spatiotemporal Dynamics and Control of Cardiac Alternans

2018 ◽  
Author(s):  
Xiaopeng Zhao ◽  
Elena G. Tolkacheva
Keyword(s):  
Cardiac Arrest ◽  
Sudden Cardiac Arrest ◽  
Cellular Level ◽  
Reduced Order Model ◽  
Western World ◽  
Order Model ◽  
Reduced Order ◽  
Dynamics And Control ◽  
Cardiac Alternans ◽  
And Control

Sudden cardiac arrest, caused primarily by ventricular fibrillation, is one of the leading causes of mortality in the Western world. There is a compelling need for risk stratification to identify patients at risk for sudden cardiac arrest. Cardiac alternans, a recognized harbinger of sudden cardiac arrest, manifests as a beat-to-beat alternation in action potential duration (cellular level) or in electrocardiogram morphology (whole heart level). Although much progress has been made to understand the mechanisms of alternans, predicting and control of alternans, especially at the heart level, remain great challenges. Current approaches to predict cardiac alternans based on restitution properties of the heart are either too simple to be valid or too complex to be useful. In this work, we developed a reduced order model from the amplitude equation to investigate dynamics and control of alternans in cardiac fiber, i.e. beyond single cell level. Detailed bifurcation and stability analyses were carried out to illustrate complex spatiotemporal patterns of alternans and the limitations in feedback control due to spatial effect.

scholarly journals Individual-based modeling of COVID-19 transmission in college communities

2021 ◽  
Author(s):  
Qimin Huang ◽  
Martial Ndeffo-Mbah ◽  
Anirban Mondal ◽  
Sara Lee ◽  
David Gurarie
Keyword(s):  
Risk Reduction ◽  
Disease Transmission ◽  
Herd Immunity ◽  
The United States ◽  
Transmission Risk ◽  
Effective Control ◽  
Social Activities ◽  
Modeling Framework ◽  
Risk Reduction Measures ◽  
And Control

The ongoing COVID-19 pandemic has created major public health and socio-economic challenges across the United States. Among them are challenges to the educational system where college administrators are struggling with the questions of how to reopen in-person activities while prioritizing student safety. To help address this challenge, we developed a flexible computational framework to model the spread and control of COVID-19 on a residential college campus. The modeling framework accounts for heterogeneity in social interactions, activities, disease progression, and control interventions. The relative contribution of classroom, dorm, and social activities to disease transmission were explored. We observed that the dorm has the highest contribution to disease transmission followed by classroom and social activities. Without vaccination, frequent (weekly) random testing coupled with risk reduction measures (e.g. facial mask,) in classroom, dorm, and social activities is the most effective control strategy to mitigate the spread of COVID-19 on college campuses. Moreover, since random screening testing allows for the successful and early detection of both asymptomatic and symptomatic individuals, it successfully reduces the transmission rate such that the maximum quarantine capacity is far lower than expected to further reduce the economic burden caused from quarantine. With vaccination, herd immunity is estimated to be achievable by 50% to 80% immunity coverage. In the absence of herd immunity, simulations indicate that it is optimal to keep some level of transmission risk reduction measures in classroom, dorm, and social activities, while testing at a lower frequency. Though our quantitative results are likely provisional on our model assumptions, extensive sensitivity analysis confirms the robustness of their qualitative nature.

scholarly journals State-level needs for social distancing and contact tracing to contain COVID-19 in the United States 

2020 ◽  
Author(s):  
Weihsueh A. Chiu ◽  
Rebecca Fischer ◽  
Martial L. Ndeffo-Mbah
Keyword(s):  
Large Scale ◽  
District Of Columbia ◽  
State Level ◽  
The United States ◽  
Contact Tracing ◽  
Social Distancing ◽  
Epidemic Curve ◽  
Dynamics And Control ◽  
And Control ◽  
The Impact

Abstract Starting in mid-May 2020, many US states began relaxing social distancing measures that were put in place to mitigate the spread of COVID-19. To evaluate the impact of relaxation of restrictions on COVID-19 dynamics and control, we developed a transmission dynamic model and calibrated it to US state-level COVID-19 cases and deaths. We used this model to evaluate the impact of social distancing, testing and contact tracing on the COVID-19 epidemic in each state. As of July 22, 2020, we found only three states were on track to curtail their epidemic curve. Thirty-nine states and the District of Columbia may have to double their testing and/or tracing rates and/or rolling back reopening by 25%, while eight states require an even greater measure of combined testing, tracing, and distancing. Increased testing and contact tracing capacity is paramount for mitigating the recent large-scale increases in U.S. cases and deaths.

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