Elena Gubar

Bio: Elena Gubar is an academic researcher from Saint Petersburg State University. The author has contributed to research in topics: Population & Malware. The author has an hindex of 6, co-authored 22 publications receiving 82 citations.

Optimal Control of Heterogeneous Mutating Viruses

Abstract: Different strains of influenza viruses spread in human populations during every epidemic season. As the size of an infected population increases, the virus can mutate itself and grow in strength. The traditional epidemic SIR model does not capture virus mutations and, hence, the model is not sufficient to study epidemics where the virus mutates at the same time as it spreads. In this work, we establish a novel framework to study the epidemic process with mutations of influenza viruses, which couples the SIR model with replicator dynamics used for describing virus mutations. We formulated an optimal control problem to study the optimal strategies for medical treatment and quarantine decisions. We obtained structural results for the optimal strategies and used numerical examples to corroborate our results.

Optimal impulse control of bi-virus SIR epidemics with application to heterogeneous Internet of Things

Abstract: With the emerging Internet of Things (IoT) technologies, malware spreading over increasingly connected networks becomes a new security concern. To capture the heterogeneous nature of the IoT networks, we propose a continuous-time Susceptible-Infected-Recovered (SIR) epidemic model with two types of malware for heterogeneous populations over a large network of devices. The malware control mechanism is to patch an optimal fraction of the infected nodes at discrete points in time, which leads to an impulse controller. We use the Pontryagin's minimum principle for impulsive systems to obtain an optimal structure of the controller and use numerical experiments to demonstrate the computation of the optimal control and the controlled dynamics.

Optimal Control of Multi-strain Epidemic Processes in Complex Networks

Abstract: The emergence of new diseases, such as HIV/AIDS, SARS, and Ebola, represent serious problems for the public health and medical science research to address. Despite the rapid development of vaccines and drugs, one challenge in disease control is the fact that one pathogen sometimes generates many strains with different spreading features. Hence it is of critical importance to investigate multi-strain epidemic dynamics and its associated epidemic control strategies. In this paper, we investigate two controlled multi-strain epidemic models for heterogeneous populations over a large complex network and obtain the structure of optimal control policies for both models. Numerical examples are used to corroborate the analytical results.

Propagation of information over the network of taxpayers in the model of tax auditing

Abstract: Tax control is one of the most important tools for the administration of the tax system (fiscal, social, regulatory and control). Tax audit enables to increase the revenue of taxes and fees in the state budget. Assume that each taxpayer can declare his income less then his true income level, however total tax audits of the taxpayers' population is economically unreasonable and even selective tax audits are not always profitable. Though, the tax authority needs to stimulate taxpayers to pay taxes, correspondingly to their true income. One possible way of such stimulation is spreading of information about future tax auditing. In this case the propagation of the information can be viewed as an “infection of the mind”, and its spreading shows an interesting resemblance to that of epidemics. To describe the spreading process we can use a modification of classical Susceptible-Infected-Recovery (SIR) model. We study a model of information spreading in large population of taxpayers and describe the dynamics of the model on complex social networks. We formulate an optimal control problem for the tax auditing policy and analyze the behavior of agents in different subgroups depending on the social connections between their agents.

A Survey of Internet of Things (IoT) Authentication Schemes

Abstract: The Internet of Things (IoT) is the ability to provide everyday devices with a way of identification and another way for communication with each other. The spectrum of IoT application domains is very large including smart homes, smart cities, wearables, e-health, etc. Consequently, tens and even hundreds of billions of devices will be connected. Such devices will have smart capabilities to collect, analyze and even make decisions without any human interaction. Security is a supreme requirement in such circumstances, and in particular authentication is of high interest given the damage that could happen from a malicious unauthenticated device in an IoT system. This paper gives a near complete and up-to-date view of the IoT authentication field. It provides a summary of a large range of authentication protocols proposed in the literature. Using a multi-criteria classification previously introduced in our work, it compares and evaluates the proposed authentication protocols, showing their strengths and weaknesses, which constitutes a fundamental first step for researchers and developers addressing this domain.

Viral infections of humans: epidemiology and control

Abstract: The third edition of this book has been completely revised and updated, and new chapters have been added on Hantanvirus by Karl Johnson, on retroviruses by William Blattner, and on hepatocellular carcinoma by Joseph Melnick. New authors have replaced previous authors for several chapters. These include Karl Johnson on arenaviruses, Stephen Hadler and Harold Margolin on viral hepatitis, Paul Glezen and Robert Couch on influenza, Alfred S. Evans and Guy de-The on Burkitt lymphoma, and Joseph Melnick, William Rawls, and Ervin Adam on cervical cancer. A summary of the major advances since the last edition in 1982 has been provided by each contributor as given below. Overall, it is clear that the rapid advances in molecular virology, monoclonal antibody, and rapid diagnostic techniques dominate the progress since the last edition and provide a better understanding of pathogenesis, newer tools for epidemiologic investigation, and new methods for vac cine production. Although there is repetition in mention of these advances as written by each contributor, the editor has let these stand to let the reader know how each interprets the impact of these new developments. I. Introduction and Concepts Chapter 1. Epidemiologic Concepts and Methods: The sections on control of infectious diseases has been much expanded to cover progress and problems in both developed and developing countries, the concepts of eradication and elimination, and the means to assess the need and effectiveness of immuniza tion programs."

Social capital and the reproduction of economic inequality in polarized societies

Abstract: This paper explores the idea of how wealth is distributed across social groups (ethnic or language groups, gender, etc.) and how such distribution fundamentally affects the evolution of economic inequality. By providing microfoundations suitable for this exploration, the paper hopes to enhance the understanding of when social forces contribute to the reproduction of economic inequality. In tackling this issue, the paper offers contributions in two domains. First, it models social capital as a real capital asset with direct use and collateral value. Second, it extends the concepts of identity, alienation and polarization used by Esteban and Ray (1994). This generalization permits consideration of the multiple characteristics that shape social identity, inclusion and exclusion. It also underwrites a higher-order measure of socioeconomic polarization that permits exploration of the hypothesis that economic inequality is most pernicious and persistent when it is socially embedded. Among other things the paper shows that holding constant the initial levels of economic polarization and wealth inequality, higher socioeconomic polarization increases subsequent income and wealth inequality. Far from being a distributionally neutral panacea for missing markets, social capital in this model may itself generate exclusion and deepen social and economic cleavages.

Modelling and optimal control of multi strain epidemics, with application to COVID-19.

Abstract: Reinfection and multiple viral strains are among the latest challenges in the current COVID-19 pandemic. In contrast, epidemic models often consider a single strain and perennial immunity. To bridge this gap, we present a new epidemic model that simultaneously considers multiple viral strains and reinfection due to waning immunity. The model is general, applies to any viral disease and includes an optimal control formulation to seek a trade-off between the societal and economic costs of mitigation. We validate the model, with and without mitigation, in the light of the COVID-19 epidemic in England and in the state of Amazonas, Brazil. The model can derive optimal mitigation strategies for any number of viral strains, whilst also evaluating the effect of distinct mitigation costs on the infection levels. The results show that relaxations in the mitigation measures cause a rapid increase in the number of cases, and therefore demand more restrictive measures in the future.