245 results match your criteria Chaos Solitons & Fractals[Journal]


Stability of bubble-like fluxons in disk-shaped Josephson junctions in the presence of a coaxial dipole current.

Chaos 2020 Jun;30(6):063132

Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Chile.

We investigate analytically and numerically the stability of bubble-like fluxons in disk-shaped heterogeneous Josephson junctions. Using ring solitons as a model of bubble fluxons in the two-dimensional sine-Gordon equation, we show that the insertion of coaxial dipole currents prevents their collapse. We characterize the onset of instability by introducing a single parameter that couples the radius of the bubble fluxon with the properties of the injected current. Read More

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http://dx.doi.org/10.1063/5.0006226DOI Listing

Spontaneous symmetry breaking in purely nonlinear fractional systems.

Chaos 2020 Jun;30(6):063131

State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an 710119, China.

Spontaneous symmetry breaking, a spontaneous course of breaking the spatial symmetry (parity) of the system, is known to exist in many branches of physics, including condensed-matter physics, high-energy physics, nonlinear optics, and Bose-Einstein condensates. In recent years, the spontaneous symmetry breaking of solitons in nonlinear wave systems is broadly studied; understanding such a phenomenon in nonlinear fractional quantum mechanics with space fractional derivatives (the purely nonlinear fractional systems whose fundamental properties are governed by a nonlinear fractional Schrödinger equation), however, remains pending. Here, we survey symmetry breaking of solitons in fractional systems (with the fractional diffraction order being formulated by the Lévy index α) of a nonlinear double-well structure and find several kinds of soliton families in the forms of symmetric and anti-symmetric soliton states as well as asymmetric states. Read More

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http://dx.doi.org/10.1063/5.0006050DOI Listing

Prediction and analysis of COVID-19 positive cases using deep learning models: A descriptive case study of India.

Chaos Solitons Fractals 2020 Oct 17;139:110017. Epub 2020 Jun 17.

Department of Electrical Engineering, Indian Institute of Technology, Delhi, New Delhi, India.

In this paper, Deep Learning-based models are used for predicting the number of novel coronavirus (COVID-19) positive reported cases for 32 states and union territories of India. Recurrent neural network (RNN) based long-short term memory (LSTM) variants such as Deep LSTM, Convolutional LSTM and Bi-directional LSTM are applied on Indian dataset to predict the number of positive cases. LSTM model with minimum error is chosen for predicting daily and weekly cases. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7298499PMC
October 2020

Global dynamics of a fractional order model for the transmission of HIV epidemic with optimal control.

Chaos Solitons Fractals 2020 Sep 18;138:109826. Epub 2020 Jun 18.

Faculty of Mathematics and Statistics, Ton Duc Thang University, Ho Chi Minh City, Vietnam.

In this paper, a nonlinear fractional order epidemic model for HIV transmission is proposed and analyzed by including extra compartment namely exposed class to the basic SIR epidemic model. Also, the infected class of female sex workers is divided into unaware infectives and the aware infectives. The focus is on the spread of HIV by female sex workers through prostitution, because in the present world sexual transmission is the major cause of the HIV transmission. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301891PMC
September 2020

Modeling and prediction of COVID-19 pandemic using Gaussian mixture model.

Chaos Solitons Fractals 2020 Sep 16;138:110023. Epub 2020 Jun 16.

Department of Electrical Engineering, Indian Institute of Technology Delhi, Delhi, India.

COVID-19 is caused by a novel coronavirus and has played havoc on many countries across the globe. A majority of the world population is now living in a restricted environment for more than a month with minimal economic activities, to prevent exposure to this highly infectious disease. Medical professionals are going through a stressful period while trying to save the larger population. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296328PMC
September 2020

Time series prediction of COVID-19 by mutation rate analysis using recurrent neural network-based LSTM model.

Chaos Solitons Fractals 2020 Sep 13;138:110018. Epub 2020 Jun 13.

Centre for Biomedical Physics, School of Healthcare and Medical Sciences, Sunway University, 47500 Bandar Sunway, Selangor, Malaysia.

SARS-CoV-2, a novel coronavirus mostly known as COVID-19 has created a global pandemic. The world is now immobilized by this infectious RNA virus. As of June 15, already more than 7. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293453PMC
September 2020
1.448 Impact Factor

Comparative analysis and forecasting of COVID-19 cases in various European countries with ARIMA, NARNN and LSTM approaches.

Chaos Solitons Fractals 2020 Sep 13;138:110015. Epub 2020 Jun 13.

Turkish State Railways, Ankara, Turkey.

In this study, confirmed COVID-19 cases of Denmark, Belgium, Germany, France, United Kingdom, Finland, Switzerland and Turkey were modeled with Auto-Regressive Integrated Moving Average (ARIMA), Nonlinear Autoregression Neural Network (NARNN) and Long-Short Term Memory (LSTM) approaches. Six model performance metric were used to select the most accurate model (MSE, PSNR, RMSE, NRMSE, MAPE and SMAPE). According to the results of the first step of the study, LSTM was found the most accurate model. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293493PMC
September 2020

Novel fractional order SIDARTHE mathematical model of COVID-19 pandemic.

Authors:
M Higazy

Chaos Solitons Fractals 2020 Sep 13;138:110007. Epub 2020 Jun 13.

Department of Mathematics and Statistics, Faculty of Science, Taif University, Saudi Arabia.

Nowadays, COVID-19 has put a significant responsibility on all of us around the world from its detection to its remediation. The globe suffer from lockdown due to COVID-19 pandemic. The researchers are doing their best to discover the nature of this pandemic and try to produce the possible plans to control it. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293538PMC
September 2020

A novel mathematics model of covid-19 with fractional derivative. Stability and numerical analysis.

Chaos Solitons Fractals 2020 Sep 17;138:110006. Epub 2020 Jun 17.

Department of Mathematics, College of Science, King Saud University, P.O. Box 1142, Riyadh 11989, Saudi Arabia.

a mathematical model depicting the spread of covid-19 epidemic and implementation of population covid-19 intervention in Italy. The model has 8 components leading to system of 8 ordinary differential equations. In this paper, we investigate the model using the concept of fractional differential operator. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.110006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7298553PMC
September 2020

Analysis for fractional dynamics of Ebola virus model.

Authors:
Harendra Singh

Chaos Solitons Fractals 2020 Sep 16;138:109992. Epub 2020 Jun 16.

Department of Mathematics, Post-Graduate College, Ghazipur 233001, Uttar Pradesh, India.

Ebola virus is very challenging problem of the world. The main purpose of this work is to study fractional Ebola virus model. An efficient computational method based on iterative scheme is proposed to solve fractional Ebola model numerically. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109992DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297191PMC
September 2020

Implicit Riesz wavelets based-method for solving singular fractional integro-differential equations with applications to hematopoietic stem cell modeling.

Chaos Solitons Fractals 2020 Sep 17;138:109991. Epub 2020 Jun 17.

Kuban State Agrarian University, Russia.

Riesz wavelets in have been proven as a useful tool in the context of both pure and numerical analysis in many applications, due to their well prevailing and recognized theory and its natural properties such as sparsity and stability which lead to a well-conditioned scheme. In this paper, an effective and accurate technique based on Riesz wavelets is presented for solving weakly singular type of fractional order integro-differential equations with applications to solve system of fractional order model that describe the dynamics of uninfected, infected and free virus carried out by cytotoxic T lymphocytes (CTL). The Riesz wavelet in this work is constructed via the smoothed pseudo-splines refinable functions. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109991DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297698PMC
September 2020

A nonlinear epidemiological model considering asymptotic and quarantine classes for SARS CoV-2 virus.

Chaos Solitons Fractals 2020 Sep 4;138:109953. Epub 2020 Jun 4.

Department of Mathematics, National Institute of Technology, Hamirpur 177001, India.

In this article, we develop a mathematical model considering susceptible, exposed, infected, asymptotic, quarantine/isolation and recovered classes as in case of COVID-19 disease. The facility of quarantine/isolation have been provided to both exposed and infected classes. Asymptotic individuals either recovered without undergo treatment or moved to infected class after some duration. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269963PMC
September 2020

Assessing functional propagation patterns in COVID-19.

Chaos Solitons Fractals 2020 Sep 12;138:109993. Epub 2020 Jun 12.

Fondazione Istituto Italiano di Tecnologia, Ferrara, Italy.

Among the many efforts done by the scientific community to help coping with the COVID-19 pandemic, one of the most important has been the creation of models to describe its propagation, as these are expected to guide the deployment of containment and health policies. These models are commonly based on exogenous information, as e.g. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109993DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290208PMC
September 2020

Investigating the dynamics of COVID-19 pandemic in India under lockdown.

Chaos Solitons Fractals 2020 Sep 10;138:109988. Epub 2020 Jun 10.

Amity University Mumbai, Panvel, Maharashtra, 410206, India.

In this paper, we investigate the ongoing dynamics of COVID-19 in India after its emergence in Wuhan, China in December 2019. We discuss the effect of nationwide lockdown implemented in India on March 25, 2020 to prevent the spread of COVID-19. Susceptible-Exposed-Infectious-Recovered (SEIR) model is used to forecast active COVID-19 cases in India considering the effect of nationwide lockdown and possible inflation in the active cases after its removal on May 3, 2020. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109988DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284270PMC
September 2020

Coronavirus pandemic: A predictive analysis of the peak outbreak epidemic in South Africa, Turkey, and Brazil.

Chaos Solitons Fractals 2020 Sep 5;138:109971. Epub 2020 Jun 5.

Department of Engineering Science, Kermanshah University of Technology, Kermanshah, Iran.

In this research, we are interested in predicting the epidemic peak outbreak of the Coronavirus in South Africa, Turkey, and Brazil. Until now, there is no known safe treatment, hence the immunity system of the individual has a crucial role in recovering from this contagious disease. In general, the aged individuals probably have the highest rate of mortality due to COVID-19. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274585PMC
September 2020

Novel Corona virus disease infection in Tunisia: Mathematical model and the impact of the quarantine strategy.

Chaos Solitons Fractals 2020 Sep 10;138:109969. Epub 2020 Jun 10.

ISSATs and MaPSFA, ESSTHS, University of Sousse-Tunisia, Tunisia.

Corona virus disease (COVID-19) is an extremely serious infection with an extremely high death rate worldwide. In March, the disease was declared a "global pandemic" by the World Health Organization (WHO). Until now, there is no known vaccine or drug, since the unknown things related to the disease are more important than our theoretical and empirical knowledge. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284269PMC
September 2020

Analysis of the mitigation strategies for COVID-19: .

Chaos Solitons Fractals 2020 Sep 5;138:109968. Epub 2020 Jun 5.

Department of Mathematics and Applied Mathematics, University of Limpopo, South Africa.

In this article, a mathematical model for the transmission of COVID-19 disease is formulated and analysed. It is shown that the model exhibits a backward bifurcation at when recovered individuals do not develop a permanent immunity for the disease. In the absence of reinfection, it is proved that the model is without backward bifurcation and the disease free equilibrium is globally asymptotically stable for . Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274644PMC
September 2020

Application of deep learning for fast detection of COVID-19 in X-Rays using nCOVnet.

Chaos Solitons Fractals 2020 Sep 28;138:109944. Epub 2020 May 28.

Department of Computer Science and Engineering, Jaypee University of Information Technology, Waknaghat, Solan, HP, 173 234, India.

Presently, COVID-19 has posed a serious threat to researchers, scientists, health professionals, and administrations around the globe from its detection to its treatment. The whole world is witnessing a lockdown like situation because of COVID-19 pandemic. Persistent efforts are being made by the researchers to obtain the possible solutions to control this pandemic in their respective areas. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254021PMC
September 2020

A mathematical model of the evolution and spread of pathogenic coronaviruses from natural host to human host.

Chaos Solitons Fractals 2020 Sep 9;138:109931. Epub 2020 Jun 9.

Department of Mathematics and General Sciences, Prince Sultan University, Riyadh, Saudi Arabia.

Coronaviruses are highly transmissible and are pathogenic viruses of the 21st century worldwide. In general, these viruses are originated in bats or rodents. At the same time, the transmission of the infection to the human host is caused by domestic animals that represent in the habitat the intermediate host. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109931DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7280153PMC
September 2020

Modeling Nigerian Covid-19 cases: A comparative analysis of models and estimators.

Chaos Solitons Fractals 2020 Sep 9;138:109911. Epub 2020 Jun 9.

Department of Agric-Economics and Farm Management, University of Ilorin, Nigeria.

COVID-19 remains a major pandemic currently threatening all the countries of the world. In Nigeria, there were 1, 932 COVID-19 confirmed cases, 319 discharged cases and 58 deaths as of 30th April 2020. This paper, therefore, subjected the daily cumulative reported COVID-19 cases of these three variables to nine (9) curve estimation statistical models in simple, quadratic, cubic, and quartic forms. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7282783PMC
September 2020

A quantitative and qualitative analysis of the COVID-19 pandemic model.

Chaos Solitons Fractals 2020 Sep 25;138:109932. Epub 2020 May 25.

Department of Mathematics and Statistics, Hazara University, Mansehra 21300, Pakistan.

Global efforts around the world are focused on to discuss several health care strategies for minimizing the impact of the new coronavirus (COVID-19) on the community. As it is clear that this virus becomes a public health threat and spreading easily among individuals. Mathematical models with computational simulations are effective tools that help global efforts to estimate key transmission parameters and further improvements for controlling this disease. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109932DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247488PMC
September 2020

The resumption of sports competitions after COVID-19 lockdown: The case of the Spanish football league.

Chaos Solitons Fractals 2020 Sep 4;138:109964. Epub 2020 Jun 4.

Grupo Interdisciplinar de Sistemas Complejos (GISC), Spain.

In this work, we present a stochastic discrete-time model adapted to describe the propagation of COVID-19 during a football tournament. Specifically, we are concerned about the re-start of the Spanish national football league, , which is currently -May 2020- stopped with 11 fixtures remaining. Our model includes two additional states of an individual, confined and quarantined, which are reached when an individual presents COVID-19 symptoms or has undergone a virus test with a positive result. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109964DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269962PMC
September 2020

How to reduce epidemic peaks keeping under control the time-span of the epidemic.

Authors:
Mariano Cadoni

Chaos Solitons Fractals 2020 Sep 5;138:109940. Epub 2020 Jun 5.

Dipartimento di Fisica, Università di Cagliari, Cittadella Universitaria, Monserrato 09042, Italy.

One of the main challenges of the measures against the COVID-19 epidemic is to reduce the amplitude of the epidemic peak without increasing without control its timescale. We investigate this problem using the SIR model for the epidemic dynamics, for which reduction of the epidemic peak can be achieved only at the price of increasing the time of its occurrence and its entire time-span . By means of a time reparametrization we linearize the equations for the SIR dynamics. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109940DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274126PMC
September 2020

Modeling the dynamics of viral infections in presence of latently infected cells.

Chaos Solitons Fractals 2020 Jul 4;136:109916. Epub 2020 Jun 4.

Department of Mathematics, Gauhati University, Guwahati 781014, India.

The study aims to develop a new mathematical model in order to explain the dynamics of viral infections in vivo such as HIV infection. The model includes three classes of cells, takes into account the cure of infected cells in latent period and also incorporates three modes of transmission. The mention modes are modeled by three general incidence functions covering several special cases available in the literature. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271877PMC

Time Series Analysis and Forecast of the COVID-19 Pandemic in India using Genetic Programming.

Chaos Solitons Fractals 2020 Sep 30;138:109945. Epub 2020 May 30.

Faculty of Engineering & Information Technology, University of Technology Sydney, NSW 2007, Australia.

COVID-19 declared as a global pandemic by WHO, has emerged as the most aggressive disease, impacting more than 90% countries of the world. The virus started from a single human being in China, is now increasing globally at a rate of 3% to 5% daily and has become a never ending process. Some studies even predict that the virus will stay with us forever. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109945DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7260529PMC
September 2020

Mathematical modeling of COVID-19 fatality trends: Death kinetics law versus infection-to-death delay rule.

Chaos Solitons Fractals 2020 Jul 30;136:109891. Epub 2020 May 30.

Institute for Mechanics of Materials and Structures, Vienna University of Technology (TU Wien), Karlsplatz 13/202, Vienna 1040, Austria.

The COVID-19 pandemic has world-widely motivated numerous attempts to properly adjust classical epidemiological models, namely those of the SEIR-type, to the spreading characteristics of the novel Corona virus. In this context, the fundamental structure of the differential equations making up the SEIR models has remained largely unaltered-presuming that COVID-19 may be just "another epidemic". We here take an alternative approach, by investigating the relevance of one key ingredient of the SEIR models, namely the death kinetics law. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7261113PMC

The impact of COVID-19 pandemic upon stability and sequential irregularity of equity and cryptocurrency markets.

Chaos Solitons Fractals 2020 Sep 28;138:109936. Epub 2020 May 28.

Department of Economics, European University Institute, Florence, Italy.

We explore the evolution of the informational efficiency in 45 cryptocurrency markets and 16 international stock markets before and during COVID-19 pandemic. The measures of Largest Lyapunov Exponent (LLE) based on the Rosenstein's method and Approximate Entropy (ApEn), which are robust to small samples, are applied to price time series in order to estimate degrees of stability and irregularity in cryptocurrency and international stock markets. The amount of regularity infers on the unpredictability of fluctuations. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254002PMC
September 2020

COVID-19 created chaos across the globe: Three novel quarantine epidemic models.

Chaos Solitons Fractals 2020 Sep 25;138:109928. Epub 2020 May 25.

Department of Mathematics, Ramgarh Engineering College, Ramgarh, India.

The latest version of human coronavirus said to be COVID-19 came out as a sudden pandemic disease within human population and in the absence of vaccination and proper treatment till date, it daunting threats heavily to human lives, infecting more than 12, 11, 214 people and death more than 67, 666 people in 208 countries across the globe as on April 06, 2020, which is highly alarming. When no treatment or vaccine is available till date and to avoid COVID-19 to be transmitted in the community, social distancing is the only way to prevent the disease, which is well taken into account in our novel epidemic models as a special compartment, that is, home isolation. Based on the transmitting behavior of COVID-19 in the human population, we develop three quarantine models of this pandemic taking into account the compartments: susceptible population, immigrant population, home isolation population, infectious population, hospital quarantine population, and recovered population. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247522PMC
September 2020

Statistical analysis of forecasting COVID-19 for upcoming month in Pakistan.

Chaos Solitons Fractals 2020 Sep 25;138:109926. Epub 2020 May 25.

Department of Mathematics, University of Malakand, Chakdara Dir (L), KPK, Pakistan.

In this paper, we have conducted analysis based on data obtained from National Institute of Health (NIH) - Islamabad and produced a forecast of COVID-19 confirmed cases as well as the number of deaths and recoveries in Pakistan using the Auto-Regressive Integrated Moving Average Model (ARIMA). The fitted forecasting models revealed high exponential growth in the number of confirmed cases, deaths and recoveries in Pakistan. Based on our model prediction the number of confirmed cases will be increased by 2. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109926DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247520PMC
September 2020
1.448 Impact Factor

Analysis of Spatial Spread Relationships of Coronavirus (COVID-19) Pandemic in the World using Self Organizing Maps.

Chaos Solitons Fractals 2020 Sep 21;138:109917. Epub 2020 May 21.

Tijuana Institute of Technology, Tijuana, Mexico.

We describe in this paper an analysis of the spatial evolution of coronavirus pandemic around the world by using a particular type of unsupervised neural network, which is called self-organizing maps. Based on the clustering abilities of self-organizing maps we are able to spatially group together countries that are similar according to their coronavirus cases, in this way being able to analyze which countries are behaving similarly and thus can benefit by using similar strategies in dealing with the spread of the virus. Publicly available datasets of coronavirus cases around the globe from the last months have been used in the analysis. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109917DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7241408PMC
September 2020

Lessons from being challenged by COVID-19.

Chaos Solitons Fractals 2020 Aug 23;137:109923. Epub 2020 May 23.

Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Física, & IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428, Argentina.

We present results of different approaches to model the evolution of the COVID-19 epidemic in Argentina, with a special focus on the megacity conformed by the city of Buenos Aires and its metropolitan area, including a total of 41 districts with over 13 million inhabitants. We first highlight the relevance of interpreting the early stage of the epidemic in light of incoming infectious travelers from abroad. Next, we critically evaluate certain proposed solutions to contain the epidemic based on instantaneous modifications of the reproductive number. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245296PMC

COVID-19 spreading in Rio de Janeiro, Brazil: Do the policies of social isolation really work?

Authors:
Nuno Crokidakis

Chaos Solitons Fractals 2020 Jul 23;136:109930. Epub 2020 May 23.

Instituto de Física, Universidade Federal Fluminense, Niterói, RJ, Brazil.

The recent Coronavirus has been spreading through all the world fastly. In this work we focus on the evolution of the COVID-19 in one of the most populous Brazilian states, namely the Rio de Janeiro state. The first case was reported in March 5, 2020, thus we have a considerable amount of available data to make a good analysis. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109930DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245288PMC

A multi-group SEIRA model for the spread of COVID-19 among heterogeneous populations.

Chaos Solitons Fractals 2020 Jul 25;136:109925. Epub 2020 May 25.

Centre for Biotechnology and Bioengineering, Universidad de Chile, Beauchef 851, Santiago 8370448, Chile.

The outbreak and propagation of COVID-19 have posed a considerable challenge to modern society. In particular, the different restrictive actions taken by governments to prevent the spread of the virus have changed the way humans interact and conceive interaction. Due to geographical, behavioral, or economic factors, different sub-groups among a population are more (or less) likely to interact, and thus to spread/acquire the virus. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7247502PMC

Forecast and evaluation of COVID-19 spreading in USA with reduced-space Gaussian process regression.

Chaos Solitons Fractals 2020 Jul 22;136:109924. Epub 2020 May 22.

Universidad Nacional de San Agustín de Arequipa, Perú.

In this report, we analyze historical and forecast infections for COVID-19 death based on Reduced-Space Gaussian Process Regression associated to chaotic Dynamical Systems with information obtained in 82 days with continuous learning, day by day, from January 21 , 2020 to April 12 . According last results, COVID-19 could be predicted with Gaussian models mean-field models can be meaning- fully used to gather a quantitative picture of the epidemic spreading, with infections, fatality and recovery rate. The forecast places the peak in USA around July 14 2020, with a peak number of 132,074 death with infected individuals of about 1,157,796 and a number of deaths at the end of the epidemics of about 132,800. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7242925PMC

Modelling the spread of COVID-19 with new fractal-fractional operators: Can the lockdown save mankind before vaccination?

Authors:
Abdon Atangana

Chaos Solitons Fractals 2020 Jul 29;136:109860. Epub 2020 May 29.

Institute for Groundwater Studies, Faculty of Natural and Agricultural Sciences, University of the Free State, South Africa.

Countries around the world are implementing lock-down measures in a bid to flatten the curve of the new deadly COVID-19 disease. Our paper does not claim to have found the cure for COVID-19, neither does it claim that the suggested model have taken into account all the complexities around the spread of the disease. Nonetheless, the fundamental question asked in this paper is to know if within the conditions taken into account in this suggested model, the integral lock-down is effective in saving human lives. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109860DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7256018PMC

Short-term forecasting COVID-19 cumulative confirmed cases: Perspectives for Brazil.

Chaos Solitons Fractals 2020 Jun 1;135:109853. Epub 2020 May 1.

Industrial & Systems Engineering Graduate Program (PPGEPS), Pontifical Catholic University of Parana (PUCPR) 1155, Rua Imaculada Conceicao, Curitiba, PR, 80215-901 Brazil.

The new Coronavirus (COVID-19) is an emerging disease responsible for infecting millions of people since the first notification until nowadays. Developing efficient short-term forecasting models allow forecasting the number of future cases. In this context, it is possible to develop strategic planning in the public health system to avoid deaths. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109853DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7252162PMC

Estimation of COVID-19 dynamics "on a back-of-envelope": Does the simplest SIR model provide quantitative parameters and predictions?

Chaos Solitons Fractals 2020 Jun 1;135:109841. Epub 2020 May 1.

Department of Theoretical Physics, Kursk State University, Radishcheva st., 33, Kursk 305000, Russia.

Basing on existence of the mathematically sequential reduction of the three-compartmental (Susceptible-Infected-Recovered/Removed) model to the Verhulst (logistic) equation with the parameters determined by the basic characteristic of epidemic process, this model is tested in application to the recent data on COVID-19 outbreak reported by the European Centre for Disease Prevention and Control. It is shown that such a simple model adequately reproduces the epidemic dynamics not only qualitatively but for a number of countries quantitatively with a high degree of correlation that allows to use it for predictive estimations. In addition, some features of SIR model are discussed in the context, how its parameters and conditions reflect measures attempted for the disease growth prevention that is also clearly indicated by deviations from such model solutions. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7252058PMC

Solitary phase waves in a chain of autonomous oscillators.

Chaos 2020 May;30(5):053119

Institute for Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam-Golm, Germany.

In the present paper, we study phase waves of self-sustained oscillators with a nearest-neighbor dispersive coupling on an infinite lattice. To analyze the underlying dynamics, we approximate the lattice with a quasi-continuum (QC). The resulting partial differential model is then further reduced to the Gardner equation, which predicts many properties of the underlying solitary structures. Read More

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http://dx.doi.org/10.1063/1.5144939DOI Listing

Dynamic dissipative solitons in nematics with positive anisotropies.

Soft Matter 2020 Jun;16(22):5325-5333

Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK.

Electric field induced instabilities of nematic molecules are of importance for both fundamental science and practical applications. Complex electro-hydrodynamic (EHD) effects such as electro-convection, fingerprint textures, spatiotemporal chaos, and solitons in nematics have been broadly investigated and generated much attention. In this work, dissipative solitons as a novel EHD phenomenon are realized in nematics with positive anisotropies, presumably for the first time. Read More

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http://dx.doi.org/10.1039/d0sm00676aDOI Listing

Observer and descriptor satisfying incremental quadratic constraint for class of chaotic systems and its applications in a quadrotor chaotic system.

Chaos Solitons Fractals 2020 Aug 18;137:109874. Epub 2020 May 18.

Department of Mechanical Engineering, University of Engineering and Technology, Peshawar, Pakistan.

A drone based on four rotors is considered in this research paper. Its chaotic solution is shown bounded in an inscribed sphere whose vertices are tangent to faces of octahedron. Based on concept of constrained optimization; Linear Matrix Inequalities (LMIs) satisfying quadratic constraint increment multiplier matrix , state observers and descriptors with estimated parameter is calculated. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7232101PMC

Optimal policies for control of the novel coronavirus (COVID-19).

Chaos Solitons Fractals 2020 May 16:109883. Epub 2020 May 16.

European University Institute, Department of Economics, Via delle Fontanelle, 18, I-50014, Florence, Italy.

Understanding the early transmission dynamics of diseases and estimation of the effectiveness of control policies play inevitable roles in the prevention of epidemic diseases. To this end, this paper is concerned with the design of optimal control strategies for the novel coronavirus (COVID-19). A mathematical model of severe SARS-CoV-2 transmission based on Wuhan's data is considered in this study. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109883DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7229919PMC

Analysis of the impact of COVID-19 on the correlations between crude oil and agricultural futures.

Chaos Solitons Fractals 2020 May 15:109896. Epub 2020 May 15.

Department of Mathematics, Korea University, Seoul 02841, Republic of Korea.

In this study, we explored the impact of COVID-19 on the cross-correlations between crude oil and agricultural futures markets. A multifractal detrended cross-correlation analysis (MF-DCCA) approach was utilized to analyze the cross-correlations between the Brent crude oil and agricultural futures such as London Sugar, London Wheat, USA Cotton #2, and USA Orange Juice futures. We initially confirmed their correlations by calculating the DCCA coefficient. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109896DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225722PMC

Characterization of the COVID-19 pandemic and the impact of uncertainties, mitigation strategies, and underreporting of cases in South Korea, Italy, and Brazil.

Chaos Solitons Fractals 2020 May 14:109888. Epub 2020 May 14.

Departamento de Ciência da Computação, Universidade Federal de Juiz de Fora (BR), Brazil.

By April 7th, 2020, the Coronavirus disease 2019 (COVID-19) has infected one and a half million people worldwide, accounting for over 80 thousand of deaths in 209 countries and territories around the world. The new and fast dynamics of the pandemic are challenging the health systems of different countries. In the absence of vaccines or effective treatments, mitigation policies, such as social isolation and lock-down of cities, have been adopted, but the results vary among different countries. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109888DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221372PMC

A model based study on the dynamics of COVID-19: Prediction and control.

Chaos Solitons Fractals 2020 May 13:109889. Epub 2020 May 13.

Department of Mathematics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India.

As there is no vaccination and proper medicine for treatment, the recent pandemic caused by COVID-19 has drawn attention to the strategies of quarantine and other governmental measures, like lockdown, media coverage on social isolation, and improvement of public hygiene, etc to control the disease. The mathematical model can help when these intervention measures are the best strategies for disease control as well as how they might affect the disease dynamics. Motivated by this, in this article, we have formulated a mathematical model introducing a quarantine class and governmental intervention measures to mitigate disease transmission. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218394PMC

STABILITY ANALYSIS OF THE HIV MODEL THROUGH INCOMMENSURATE FRACTIONAL-ORDER NONLINEAR SYSTEM.

Chaos Solitons Fractals 2020 May 11:109870. Epub 2020 May 11.

Kayseri University, Faculty of Applied Sciences, TR-38039, Kayseri, Turkey.

In this study, it is employed a new model of infection in the form of incommensurate fractional differential equations systems involving the Caputo fractional derivative. Existence of the model's equilibrium points has been investigated. According to some special cases of the derivative-orders in the proposed model, the asymptotic stability of the infection-free equilibrium and endemic equilibrium has been proved under certain conditions. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211765PMC

Development of New Hybrid Model of Discrete Wavelet Decomposition and Autoregressive Integrated Moving Average (ARIMA) Models in Application to One Month Forecast the Casualties Cases of COVID-19.

Chaos Solitons Fractals 2020 May 11:109866. Epub 2020 May 11.

Department of Mathematics, Sri Guru Angad Dev College, Khadoor Sahib, Tarn Taran, Punjab, India, 143117.

Everywhere around the globe, the hot topic of discussion today is the ongoing and fast-spreading coronavirus disease (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). Earlier detected in Wuhan, Hubei province, in China in December 2019, the deadly virus engulfed China and some neighboring countries, which claimed thousands of lives in February 2020. The proposed hybrid methodology involves the application of discreet wavelet decomposition to the dataset of deaths due to COVID-19, which splits the input data into component series and then applying an appropriate econometric model to each of the component series for making predictions of death cases in future. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109866DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211653PMC

On a Comprehensive Model of the Novel Coronavirus (COVID-19) Under Mittag-Leffler Derivative.

Chaos Solitons Fractals 2020 May 8:109867. Epub 2020 May 8.

Department of Mathematics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, (M.S), 431001, India.

The major purpose of the presented study is to analyze and find the solution for the model of nonlinear fractional differential equations (FDEs) describing the deadly and most parlous virus so-called coronavirus (COVID-19). The mathematical model depending of fourteen nonlinear FDEs is presented and the corresponding numerical results are studied by applying the fractional Adams Bashforth (AB) method. Moreover, a recently introduced fractional nonlocal operator known as Atangana-Baleanu (AB) is applied in order to realize more effectively. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109867DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205740PMC

Time Series Forecasting of COVID-19 transmission in Canada Using LSTM Networks.

Chaos Solitons Fractals 2020 May 8:109864. Epub 2020 May 8.

Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S0A2 Canada.

On March 11 2020, World Health Organization (WHO) declared the 2019 novel corona virus as global pandemic. Corona virus, also known as COVID-19 was first originated in Wuhan, Hubei province in China around December 2019 and spread out all over the world within few weeks. Based on the public datasets provided by John Hopkins university and Canadian health authority, we have developed a forecasting model of COVID-19 outbreak in Canada using state-of-the-art Deep Learning (DL) models. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205623PMC
May 2020
1.448 Impact Factor

Dissipative soliton stabilization by several nonlinear gradient terms.

Chaos 2020 Apr;30(4):043119

Department of Physics, University of Bayreuth, 95440 Bayreuth, Germany.

We study a single cubic complex Ginzburg-Landau equation with nonlinear gradient terms analytically and numerically. This single equation allows for the existence of stable dissipative solitons exclusively due to nonlinear gradient terms. We shed new light on the feedback loop, leading to dissipative solitons (DSs) by analyzing a mechanical analog as a function of the magnitude of the amplitude. Read More

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http://dx.doi.org/10.1063/1.5145280DOI Listing

Real-time forecasts and risk assessment of novel coronavirus (COVID-19) cases: A data-driven analysis.

Chaos Solitons Fractals 2020 Apr 30:109850. Epub 2020 Apr 30.

AERU, Indian Statistical Institute, 203, B. T. Road, Kolkata 700108, India.

The coronavirus disease 2019 (COVID-19) has become a public health emergency of international concern affecting 201 countries and territories around the globe. As of April 4, 2020, it has caused a pandemic outbreak with more than 11,16,643 confirmed infections and more than 59,170 reported deaths worldwide. The main focus of this paper is two-fold: (a) generating short term (real-time) forecasts of the future COVID-19 cases for multiple countries; (b) risk assessment (in terms of case fatality rate) of the novel COVID-19 for some profoundly affected countries by finding various important demographic characteristics of the countries along with some disease characteristics. Read More

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http://dx.doi.org/10.1016/j.chaos.2020.109850DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190506PMC