Sharif Digital Repository

Infectious diseases have always been a threat to mankind, and is the greatest causes of death of children and young people. Although this type of diseases is a serious threat to public health; the allocated resources in responding to a semi-large pandemic is inadequate. Therefore, it is important to spend the resources in the most effective and efficient ways to improve pandemic response capability. That is why considerable research be devoted to study different aspects of epidemics, and developed mathematical approaches to choose appropriate strategies in pandemic response. Since the epidemic models are simplified means to describe the transmission of disease, researchers often use these... 

Different models describing the procedure of epidemics are complicated and involving numerous factors. Some of these models that used a stochastic network for modelling epidemics had been successful in statistical prediction of spreading epidemics. However, in many cases there is no direct way to determine parameters of these models. In this thesis it has been desired to estimate those parameters based on historical data of epidemics To estimate structural parameters, concerning epidemic network, two independent inference have been studied. In the first inference, the probability of disease transmission from one person to another is estimated.
In the second, using Bayesian inference,... 

Vaccination is one of the ways of disease control and prevention, which not only protect individuals against the disease, but also reduce the disease spread rate. Mass vaccination of individuals is not always possible due to the high cost and limitation of immunization resources. Therefore, researchers are always seeking solutions to find the persons that their immunization may have a greater impact in reduction of disease spread rate. The advent of network epidemic models and the possibility of removal the secured nodes in those models, showed that this problem is equivalent to finding a limited set of individuals that their removal will eliminate or minimize the number of people at risk of... 

In this thesis, first we will have a thorough review on problems and models presented in the field of contagion in networks (spread of diseases, spread of computer viruses,etc.). Then we will investigate the basic model of virus inoculation game with purely selfish players and the modified version of it which takes into account a factor of friendship. We will discuss the results of these models including computing and comparing Nash Equilibria  

In this study, we will examine persistence of various kinds of seasonally forced epidemiological models and seasonally varying predator-prey models. The results of our study regarding persistence of the models will be shown via basic reproduction number. We will show that, in the framework of our study and under some conditions, persistence is obtained as long as the basic reproduction number is bigger than one. We will also prove that, in the framework of our study and under sufficient conditions, if the basic reproduction number is smaller than one, the species under discussion won’t survive in the predator-prey models, and the disease(s) would go extinct in the epidemiological... 

Infectious diseases have always threatened the health of human beings. One of the most important causes of mortality in human societies is infectious diseases. The spread of these diseases in society, even if does not lead to death, can have devastating effects on society. Influenza is one of the infectious diseases that has attracted much attention today. It can be mild or severe and even cause hospitalization and death. Therefore, controlling and preventing the epidemic of this disease is very important. Epidemic models are commonly used to simulate the spread of infectious diseases. In this study to identify the influenza outbreak, a stochastic multigroup SEIR model with the migration... 

Networks and the epidemiology of directly transmitted infectious diseases are fun-damentally linked. The foundations of epidemiology and early epidemiological models were based on population wide random-mixing, but in practice each individual has a finite set of contacts to whom they can pass infection; the ensemble of all such contacts forms a network. Knowledge of the structure of the network allows models to compute the epidemic dynamics at the population scale from the individual-level behaviour of infections.Motivated by the analysis of social networks, we study a model of random net-works that has both a given degree distribution and a tunable clustering coefficient.We consider two... 

Among disasters, outbreaks of pandemics account for excessive human and material damages,including a significant number of deaths. During any pandemic and once an or a set of effective vaccines have been identified/produced, governments all around the world enter a crucial phase when a crucial demand for an effective global vaccination campaign arises to vaccinate the population to stop/avoid the disease, knowing that the vaccines are not immediately available and may even become available with considerable delays (i.e., delivery and validation delays). Therefore, such phase of a pandemic is very crucial to identify and produce effective vaccines as well as to globally and equitably... 

During the covid-19 pandemic, in many countries, women's employment sector received more impact than men's. Some researchers consider this incident due to a decrease in the supply of women due to the closure of childcare centers and absenteeism in schools. Some consider this to be due to a reduction in the demand for women's labor due to the damage to the service sector. In this research, using the transition matrix, we showed that, during the epidemic period, the households in which women were employed in the pre-epidemic period (first group) had a greater reduction in income mobility than the households in which only men were employed (second group). Then, using the ordered logit of... 

Epidemics are one of the most important issues in social environments, economics systems, medicine, and other environments. In the study of the epidemics, some behaviors have been observed that are very similar to the phase transition in critical systems. For example, by changing the parameters that the epidemics process is characterized, the system’s epidemic behavior changes. Depending on the type of problem, this behavior change may be similar to continuous or discontinuous phase transitions. One of the fascinating issues that have just been taken into consideration in this area is the cooperation of two or more diseases. This means that the rate of transmission of a disease depends on... 

Complex networks serve as generic models for many social, technological and biological systems that have been shown to share a number of common structural properties such as power-law degree distribution and small-worldness. These networks determine interactions and influence the spread of diseases, behaviours and ideas. Epidemics and failures like new behaviours ideas and innovations can spread throughout a network and prevent it from doing its functionalities. In this work, we investigate error and attack tolerance of epidemic spreading in complex networks. The main content of this thesis is arranged in three sections as follows: Firstly, the effect of random and systematic failures is... 

Researching in the field of optimization of network immunizing and epidemic spreading is an active and important area. According to literature review, influential nodes are detected based on global graph metrics such as centrality measures. On the other hand, when a network infrastructure is not available and a direct or straight path between source and destination may not be accessible, one can use opportunistic networks routing protocols in Delay Tolerant Networks to recognize influential users is an appropriate approach. In this work, we use a real world three layer dataset which consists of digital data (social relations and Bluetooth contact traces) of individuals. We convert the real...