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1.
Sensors (Basel) ; 23(5)2023 Feb 22.
Article in English | MEDLINE | ID: mdl-36904620

ABSTRACT

A multiple input multiple output (MIMO) power line communication (PLC) model for industrial facilities was developed that uses the physics of a bottom-up model but can be calibrated like top-down models. The PLC model considers 4-conductor cables (three-phase conductors and a ground conductor) and has several load types, including motor loads. The model is calibrated to data using mean field variational inference with a sensitivity analysis to reduce the parameter space. The results show that the inference method can accurately identify many of the model parameters, and the model is accurate even when the network is modified.

2.
Arch Comput Methods Eng ; 28(6): 4169-4183, 2021.
Article in English | MEDLINE | ID: mdl-34335019

ABSTRACT

We present a simple, near-real-time Bayesian method to infer and forecast a multiwave outbreak, and demonstrate it on the COVID-19 pandemic. The approach uses timely epidemiological data that has been widely available for COVID-19. It provides short-term forecasts of the outbreak's evolution, which can then be used for medical resource planning. The method postulates one- and multiwave infection models, which are convolved with the incubation-period distribution to yield competing disease models. The disease models' parameters are estimated via Markov chain Monte Carlo sampling and information-theoretic criteria are used to select between them for use in forecasting. The method is demonstrated on two- and three-wave COVID-19 outbreaks in California, New Mexico and Florida, as observed during Summer-Winter 2020. We find that the method is robust to noise, provides useful forecasts (along with uncertainty bounds) and that it reliably detected when the initial single-wave COVID-19 outbreaks transformed into successive surges as containment efforts in these states failed by the end of Spring 2020.

3.
PLoS One ; 16(7): e0254319, 2021.
Article in English | MEDLINE | ID: mdl-34242349

ABSTRACT

In this paper we investigate the utility of one-dimensional convolutional neural network (CNN) models in epidemiological forecasting. Deep learning models, in particular variants of recurrent neural networks (RNNs) have been studied for ILI (Influenza-Like Illness) forecasting, and have achieved a higher forecasting skill compared to conventional models such as ARIMA. In this study, we adapt two neural networks that employ one-dimensional temporal convolutional layers as a primary building block-temporal convolutional networks and simple neural attentive meta-learners-for epidemiological forecasting. We then test them with influenza data from the US collected over 2010-2019. We find that epidemiological forecasting with CNNs is feasible, and their forecasting skill is comparable to, and at times, superior to, plain RNNs. Thus CNNs and RNNs bring the power of nonlinear transformations to purely data-driven epidemiological models, a capability that heretofore has been limited to more elaborate mechanistic/compartmental disease models.


Subject(s)
Forecasting , Neural Networks, Computer , Humans , Influenza, Human
4.
Emerg Infect Dis ; 27(3): 767-778, 2021.
Article in English | MEDLINE | ID: mdl-33622460

ABSTRACT

To increase situational awareness and support evidence-based policymaking, we formulated a mathematical model for coronavirus disease transmission within a regional population. This compartmental model accounts for quarantine, self-isolation, social distancing, a nonexponentially distributed incubation period, asymptomatic persons, and mild and severe forms of symptomatic disease. We used Bayesian inference to calibrate region-specific models for consistency with daily reports of confirmed cases in the 15 most populous metropolitan statistical areas in the United States. We also quantified uncertainty in parameter estimates and forecasts. This online learning approach enables early identification of new trends despite considerable variability in case reporting.


Subject(s)
Coronavirus Infections/epidemiology , Epidemics , Forecasting/methods , Bayes Theorem , Coronavirus , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Epidemics/prevention & control , Humans , Incidence , Models, Theoretical , Uncertainty , United States/epidemiology
5.
medRxiv ; 2021 Jan 19.
Article in English | MEDLINE | ID: mdl-32743595

ABSTRACT

To increase situational awareness and support evidence-based policy-making, we formulated a mathematical model for COVID-19 transmission within a regional population. This compartmental model accounts for quarantine, self-isolation, social distancing, a non-exponentially distributed incubation period, asymptomatic individuals, and mild and severe forms of symptomatic disease. Using Bayesian inference, we have been calibrating region-specific models daily for consistency with new reports of confirmed cases from the 15 most populous metropolitan statistical areas in the United States and quantifying uncertainty in parameter estimates and predictions of future case reports. This online learning approach allows for early identification of new trends despite considerable variability in case reporting. ARTICLE SUMMARY LINE: We report models for regional COVID-19 epidemics and use of Bayesian inference to quantify uncertainty in daily predictions of expected reporting of new cases, enabling identification of new trends in surveillance data.

6.
Comput Mech ; 66(5): 1109-1129, 2020.
Article in English | MEDLINE | ID: mdl-33041410

ABSTRACT

We demonstrate a Bayesian method for the "real-time" characterization and forecasting of partially observed COVID-19 epidemic. Characterization is the estimation of infection spread parameters using daily counts of symptomatic patients. The method is designed to help guide medical resource allocation in the early epoch of the outbreak. The estimation problem is posed as one of Bayesian inference and solved using a Markov chain Monte Carlo technique. The data used in this study was sourced before the arrival of the second wave of infection in July 2020. The proposed modeling approach, when applied at the country level, generally provides accurate forecasts at the regional, state and country level. The epidemiological model detected the flattening of the curve in California, after public health measures were instituted. The method also detected different disease dynamics when applied to specific regions of New Mexico.

7.
ArXiv ; 2020 Jul 20.
Article in English | MEDLINE | ID: mdl-32743021

ABSTRACT

To increase situational awareness and support evidence-based policy-making, we formulated two types of mathematical models for COVID-19 transmission within a regional population. One is a fitting function that can be calibrated to reproduce an epidemic curve with two timescales (e.g., fast growth and slow decay). The other is a compartmental model that accounts for quarantine, self-isolation, social distancing, a non-exponentially distributed incubation period, asymptomatic individuals, and mild and severe forms of symptomatic disease. Using Bayesian inference, we have been calibrating our models daily for consistency with new reports of confirmed cases from the 15 most populous metropolitan statistical areas in the United States and quantifying uncertainty in parameter estimates and predictions of future case reports. This online learning approach allows for early identification of new trends despite considerable variability in case reporting. We infer new significant upward trends for five of the metropolitan areas starting between 19-April-2020 and 12-June-2020.

8.
Rev Med Chir Soc Med Nat Iasi ; 119(4): 1098-105, 2015.
Article in English | MEDLINE | ID: mdl-26793855

ABSTRACT

Vaccination is considered to be the most effective and the cheapest medical intervention through which individual and collective immunisation is achieved. Statistics show that, at present, immunisation annually saves 400 million lives and protects approximately 750,000 children against disabilities of varying degrees. Approximately 80% of worldwide children are vaccinated against diphtheria, tetanus, pertussis, polio, measles, etc.; these diseases used to be considered incurable in the past. Vaccines help the body to produce antibodies; they help the immune system to detect germs and inactivate their cells. The immunological protection is installed after a variable period of time following the inoculation and is long lasting. Immunisations can be achieved in several ways: through national immunisation campaigns with general recommendation--they may be compulsory, optional or prophylactic (for the diseases for which a vaccine is available); vaccinations not included in the compulsory immunisation programmes; they may also be targeted to the contagious infectious outbreaks or to groups of population in certain situations. There is no guarantee that a vaccine will provide 100% protection. However, it will significantly reduce the risk of getting an infection. Vaccines have side effects which can be divided into reactions triggered by the vaccine or reactions exacerbated by it, without a causal relationship to the vaccine.


Subject(s)
Bacterial Vaccines/administration & dosage , Mandatory Programs/trends , Vaccination , Vaccines, Combined/administration & dosage , Viral Vaccines/administration & dosage , Bacterial Vaccines/adverse effects , Child , Diphtheria-Tetanus-Pertussis Vaccine/administration & dosage , Evidence-Based Medicine , Guidelines as Topic , Human Rights/trends , Humans , Immunization Programs/trends , Immunization Schedule , Measles Vaccine/administration & dosage , Measles-Mumps-Rubella Vaccine/administration & dosage , Patient Compliance , Poliovirus Vaccines/administration & dosage , Public Health/trends , Romania , Vaccination/standards , Vaccination/trends , Vaccines, Combined/adverse effects , Viral Vaccines/adverse effects
9.
J Am Med Inform Assoc ; 20(3): 435-40, 2013 May 01.
Article in English | MEDLINE | ID: mdl-23037798

ABSTRACT

OBJECTIVE: We discuss the use of structural models for the analysis of biosurveillance related data. METHODS AND RESULTS: Using a combination of real and simulated data, we have constructed a data set that represents a plausible time series resulting from surveillance of a large scale bioterrorist anthrax attack in Miami. We discuss the performance of anomaly detection with structural models for these data using receiver operating characteristic (ROC) and activity monitoring operating characteristic (AMOC) analysis. In addition, we show that these techniques provide a method for predicting the level of the outbreak valid for approximately 2 weeks, post-alarm. CONCLUSIONS: Structural models provide an effective tool for the analysis of biosurveillance data, in particular for time series with noisy, non-stationary background and missing data.


Subject(s)
Biosurveillance/methods , Disease Outbreaks , Models, Biological , Algorithms , Anthrax , Bioterrorism , Humans , ROC Curve
10.
Article in English | MEDLINE | ID: mdl-22868681

ABSTRACT

In this work, the problem of representing a stochastic forward model output with respect to a large number of input parameters is considered. The methodology is applied to a stochastic reaction network of competence dynamics in Bacillus subtilis bacterium. In particular, the dependence of the competence state on rate constants of underlying reactions is investigated. We base our methodology on Polynomial Chaos (PC) spectral expansions that allow effective propagation of input parameter uncertainties to outputs of interest. Given a number of forward model training runs at sampled input parameter values, the PC modes are estimated using a Bayesian framework. As an outcome, these PC modes are described with posterior probability distributions. The resulting expansion can be regarded as an uncertain response function and can further be used as a computationally inexpensive surrogate instead of the original reaction model for subsequent analyses such as calibration or optimization studies. Furthermore, the methodology is enhanced with a classification-based mixture PC formulation that overcomes the difficulties associated with representing potentially nonsmooth input-output relationships. Finally, the global sensitivity analysis based on the multiparameter spectral representation of an observable of interest provides biological insight and reveals the most important reactions and their couplings for the competence dynamics


Subject(s)
Bacillus subtilis/physiology , Computational Biology/methods , DNA Transformation Competence , Models, Biological , Models, Statistical , Bacillus subtilis/genetics , Bayes Theorem , Stochastic Processes
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