The use of millimeter-wave (mmWave) bandwidth is one key enabler to achieve the high data rates in the fifth-generation (5G) cellular systems. However, mmWave signals suffer from significant path ...loss due to high directivity and sensitivity to blockages, limiting its adoption within small-scale deployments. To enhance the coverage of mmWave communication in 5G and beyond, it is promising to deploy a large number of reconfigurable intelligent surfaces (RISs) that passively reflect mmWave signals towards desired directions. With this motivation, in this work, we study the coverage of an RIS-assisted large-scale mmWave cellular network using stochastic geometry, and derive the peak reflection power expression of an RIS and the downlink signal-to-interference ratio (SIR) coverage expression in closed forms. These analytic results clarify the effectiveness of deploying RISs in the mmWave SIR coverage enhancement, while unveiling the major role of the density ratio between active base stations (BSs) and passive RISs. Furthermore, the results show that deploying passive reflectors are as effective as equipping BSs with more active antennas in the mmWave coverage enhancement. Simulation results confirm the tightness of the closed-form expressions, corroborating our major findings based on the derived expressions.
Significant in the history of Anglo-Spanish relations and of English ventures was Drake's expedition to the West Indies in 1585-86. His raids on Spanish towns on both sides of the Atlantic were aimed ...not only to gather treasure but to bring a military challenge to the empire of Philip II. The voyage was linked also with the plantation projects of Raleigh, and ended with Drake bringing home the discouraged settlers of the first Virginia colony. Although not a financial success, the expedition attracted wide attention in England and the continent and was a prelude to the events of 1588. For over three centuries after the voyage the main source of information about it was the lively narrative, strongly propagandistic in tone, that was published in 1588 and 1589. In the present volume this account, attributed to Captain Walter Bigges, has been critically edited in the light of evidence now available from English and Spanish sources. Printed also are documents relating to ships and personnel and to financial accounts of the expedition. Included too are the journal from the vice-admiral's ship, the Primrose, edited from the original manuscript, the fragmentary journals from ships of two other major officers, and an important newsletter. Among illustrations are a previously unpublished map relating to Drake's stop at Vigo, as well as the Boazio maps, which are shown in differing sizes and details. Dr Keeler's introduction discusses the expedition in the context of Elizabethan policies in the pre-Armada years. She points out new evidence on Drake's administrative practices, on his negotiations with Spanish officials, and on his dealings with a troublesome rear-admiral. Appendices provide critical notes on the Boazio maps and on the circumstances of the publication of the Bigges account. This is a new print-on-demand hardback edition of the volume first published in 1981.
•We build a new analytical framework for the information spreading called “awareness” combined with the susceptible-infected-recovered (SIR) model.•Our model can evaluate the effect of awareness ...along with a SIR epidemic model to reduce the effect of contagious disease.•We obtain the phase diagram for different parameter comparison to show the effect of awareness.
The information spreading of awareness can prompt the manners of human to ease the infectious possibility and assist to recover swiftly. A dynamic system of Susceptible-Infected-Recovered (SIR) with Unaware-Aware (UA) process (SIR-UA) is newly developed by using compartment model through analytical approach with assumption of an infinite and well-mixed population. Moreover, individuals in a population can be classified into six states as unaware susceptible(SU), aware susceptible(SA), unaware infected(IU), aware infected(IA), unaware recovered(RU), and aware recovered(RA). Compared with previous models, the new dynamic set of equations described the more widespread situation and incorporated all possible states of Unaware-Aware (UA) with SIR process. The effect of awareness is explored carefully to show the significance on epidemic model with time steps. Consequently, the properties of parameters on the epidemic awareness model are studied to deliberate different physical situations. Finally, full phase diagrams are explored to show the epidemic sizes of susceptible and recovered individuals for various parameters.
Discussions on social media during major disasters are robust and often have multiple frames of reference. Temporal perspectives, however, are still lacking in current understandings of ...social-mediated discussions during disasters and crises, but incorporating temporal perspectives can significantly enhance environmental scanning efforts as prescribed in the issues management framework. The purpose of the current research is twofold: to apply and validate the SIR (Susceptible-Infectious-Recovered) model to examine topics’ growth over time on social media and to understand how future orientation of social media users (an indicator of temporal distance) affects their construal of a disaster through supervised machine learning. We based our analysis on Twitter discussions during the Texas winter storm in 2021. Results of the study show great fit of the SIR model for topic growth, and that temporal distance affects users’ construal of the event in line with core predictions of construal level theory. Theoretical, methodological, and practical implications on social-mediated discussions related to climate change-induced and -intensified disasters and issues management are discussed.
•The current study used the infectious disease model to examine topic growth and identify rising topics.•The study incorporated a temporal perspective by modeling topic growth over time and individuals’ future orientation.•Applying construal level theory, the study found that the differential growth rate corresponds to the centrality of the topic to the current disaster, with more central topics growing faster.•Temporal distance created a higher level of construal, focusing more on the central features of the event.•The methological approach is particularly relevant to issue monitoring and trend identification in issues management.
Once the dominant literary form, poetry was gradually eclipsed by the realist novel; indeed, by 1940 W. H. Auden was able to note, “Poetry makes nothing happen.” In The Perversity of Poetry, Dino ...Franco Felluga explores the cultural background of poetry’s marginalization by examining nineteenth-century reactions to Romantic poetry and ideology. Focusing on the work of Sir Walter Scott and Lord Byron, as well as periodical reviews, student manuals, and contemporary medical journals, the book details the period’s two contending (and equally outrageous) claims regarding poetry. Scott’s poetry, on the one hand, was continually represented as a panacea for a modern world overtaken by new principles of utilitarianism, capitalism, industrialism, and democracy. Byron’s, by contrast, was represented either as a cancer in the heart of the social order or as a contagious pandemic leading to various pathological symptoms. The book concludes with a coda on Alfred Lord Tennyson, which illustrates how the Victorian reception of Scott and Byron affected the most popular poetic genius of midcentury. Ultimately, The Perversity of Poetry uncovers how the shift to a rhetoric of health allowed critics to oppose what they perceived as a potent and potentially dangerous influence on the age, the very thing that would over the course of the century be marginalized into such obscurity: poetry, thanks to its perverse insistence on making something happen.
The Macroeconomics of Epidemics Eichenbaum, Martin S; Rebelo, Sergio; Trabandt, Mathias
The Review of financial studies,
11/2021, Letnik:
34, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Abstract
We extend the canonical epidemiology model to study the interaction between economic decisions and epidemics. Our model implies that people cut back on consumption and work to reduce the ...chances of being infected. These decisions reduce the severity of the epidemic but exacerbate the size of the associated recession. The competitive equilibrium is not socially optimal because infected people do not fully internalize the effect of their economic decisions on the spread of the virus. In our benchmark model, the best simple containment policy increases the severity of the recession but saves roughly half a million lives in the United States.
•The SIR epidemic model with delay in the context of the fractional derivative with Mittag–Leffler kernel has been considered.•The existence and the uniqueness of our proposed model in terms of the ...used fractional derivative have been addressed.•The global stability for the trivial equilibrium and the endemic equilibrium points have been investigated.•The graphical representations of the proposed solutions of the SIR epidemic model have been investigated.
The SIR epidemic model with delay in the context of the fractional derivative with Mittag–Leffler kernel has been considered. The Atangana–Baleanu fractional derivative is a non-singular fractional derivative with Mittag–Leffler kernel. The positivity of the solutions of the SIR model depends strongly on the order of the Atangana–Baleanu–Caputo fractional derivative. We investigate the existence and the uniqueness of our proposed model in terms of the used fractional derivative. The reproduction number related to the SIR epidemic model in our paper is presented. The trivial equilibrium point and the endemic equilibrium point have been proposed. The asymptotic stability for the trivial equilibrium and the endemic equilibrium points have been investigated. The global asymptotic stability of the disease-free equilibrium and the endemic equilibrium have been analyzed in terms of the Lyapunov direct method. The graphical representations of the approximate solutions of the model have been proposed.
Mathematical models are among the most successful strategies for predicting the dynamics of a disease spreading in a population. Among them, the so-called compartmental models, where the total ...population is proportionally divided into compartments, are widely used. The SIR model (Susceptible-Infected-Recovered) is one of them, where the dynamics between the compartments follows a system of nonlinear differential equations. As a result of the non-linearity of the SIR dynamics, it has no analytical solution. Therefore, some numerical methods must be used to obtain an approximate solution. In this contribution, we present simulated scenarios for the SIR model showing its stiffness, a phenomenon that implies the necessity of a small step size choice in the numerical approximation. The numerical results, in particular, show that the stiffness phenomenon increases with higher transmission rates and lower birth and mortality rates . We compare the numerical solutions and errors for the SIR model using explicit Euler, Runge Kutta, and the semi-implicit Rosenbrock methods and analyze the numerical implications of the stiffness on them. As a result, we conclude that any accurate numerical solution of the SIR model will depend on an appropriately chosen numerical method and the time step, in terms of the values of the parameters.
An accurate closed-form solution is obtained to the SIR Epidemic Model through the use of Asymptotic Approximants (Barlow et al., 2017). The solution is created by analytically continuing the ...divergent power series solution such that it matches the long-time asymptotic behavior of the epidemic model. The utility of the analytical form is demonstrated through its application to the COVID-19 pandemic.
•Asymptotic approximant method applied to epidemiology problem for the first time.•Power series solution to SIR problem is analytically continued.•Asymptotic approximant provides efficient and accurate solution to the SIR Model.
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