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The paper analyzes the optimal lockdown policy using the SQAIRD model over a network with three population groups (young, adult, and old). We show that different lockdown policies may be justified by different socioeconomic structures (objective cost functions that are either convex or concave). We also show that a lockdown policy is always better than a laissez-faire policy, and a targeted policy specific to each group outperforms a uniform policy. In our benchmark example, we consider the case of Italy. Our simulations show that: (a) a lockdown policy is always better than the laissez-faire policy because it limits the costs generated by the pandemic in an uncontrolled situation; (b) a group-specific targeted lockout policy is more effective than a uniform policy to the extent that the groups differ. The latter is a less expensive targeted policy (as it optimally minimizes direct, indirect, and vaccination costs), and it is equally effective in controlling the pandemic. One finding of particular interest is that the optimal lockdown rate should be higher for the young and elderly than for adults. This is motivated by the fact that younger individuals are more likely to spread the virus in question asymptomatically. [ABSTRACT FROM AUTHOR]

Accurate modeling of the patient flow within an Emergency Department (ED) is required by all studies dealing with the increasing and well-known problem of overcrowding. Since Discrete Event Simulation (DES) models are often adopted with the aim of assessing solutions for reducing the impact of this worldwide phenomenon, an accurate estimation of the service time of the ED processes is necessary to guarantee the reliability of the results. However, simulation models concerning EDs are frequently affected by missing data, thus requiring a proper estimation of some unknown parameters. In this paper, a simulation-based optimization approach is used to estimate the incomplete data in the patient flow within an ED by adopting a model calibration procedure. The objective function of the resulting minimization problem represents the deviation between simulation output and real data, while the constraints ensure that the response of the simulation is sufficiently accurate according to the precision required. Data from a real case study related to a big ED in Italy is used to test the effectiveness of the proposed approach. The experimental results show that the model calibration allows recovering the missing parameters, thus leading to an accurate DES model. [ABSTRACT FROM AUTHOR]

In Italy, the referendum represents the main form of direct democracy. At the national level, there exist 2 main forms of referendum: an abrogative referendum, in which the electorate is called to vote on whether they wish to abolish an existing law, and a constitutional referendum, which can be requested in some cases when a new constitutional law is approved by the Parliament. In the first case, the referendum has to meet a certain turnout requirement in order to be valid, namely, a participation quorum threshold has to be reached. The rationale for such a requirement is that, to change the status quo, a large proportion of citizens should care about the issue at stake and take part in the decision. In our work, we provide a game theoretic analysis of a voting rule with a participation quorum threshold. In particular, we focus on a binary dichotomous voting rule, in which the choices are vote "yes" and vote "no", on a 3-option dichotomous voting rule, in which there is the additional choice to "stay at home", and on a quaternary dichotomous voting rule, in which it is also possible to "abstain". The possible outcomes are two, namely "approval" and "rejection". We provide a graphical representation of these aforementioned voting rules, which allows for an easier analysis of these well-known voting scenarios, in particular focusing on the case of the Italian referendum. We analyze how the decisiveness (as a measure of agility), the blocking power (as a measure of inertia) of such voting situations, both at a collective and at an individual level, and the configurations in which a voter can become a swing voter are strongly impacted by the quorum threshold. [ABSTRACT FROM AUTHOR]

During the first wave of the COVID-19 pandemic, in France, people cleared the shelves of butter; in Italy, it was pasta; in Great Britain, it was chicken. While there may be cultural disagreement on what is essential, clearly, in times of crisis, consumers stockpile the 'essentials'. We address the problem of "panic buying", which is characterized by increasing demand in the face of diminishing inventory. In such cases, prices may hike and firms (retailers) selling the high-demand product are quantity takers, in terms of supply, and price setters. We consider a manufacturer who sells a scarce product to a single retailer. The retailer seeks to maximize her profit, while in contrast, the manufacturer pursues a social objective of regulating and lowering the amount that the end customer (consumer) pays (including the cost of traveling to obtain the scarce product). By analyzing the competition between the two parties, retailer and manufacturer, we find that even when the regulator (manufacturer) makes a significant social commitment, neither subsidizing the retailer nor subsidizing the consumers necessarily curbs price hikes. Furthermore, there is a threshold ratio (i.e., proportion of the end price subsidized by the regulator) that determines the minimal budget that the regulator would need to allocate in order for subsidization to make a difference to consumers. [ABSTRACT FROM AUTHOR]