This paper studies the social acceptability and feasibility of a focused protection strategy against coronavirus disease 2019 (COVID-19). We propose a control scheme to develop herd immunity while satisfying the following two basic requirements for a viable policy option. The first requirement is social acceptability: the overall deaths should be minimized for social acceptance. The second is feasibility: the healthcare system should not be overwhelmed to avoid various adverse effects. To exploit the fact that the disease severity increases considerably with age and comorbidities, we assume that some focused protection measures for those high-risk individuals are implemented and the disease does not spread within the high-risk population. Because the protected population has higher severity ratios than the unprotected population by definition, the protective measure can substantially reduce mortality in the whole population and also avoid the collapse of the healthcare system. Based on a simple susceptible-infected-recovered model, social acceptability and feasibility of the proposed strategy are summarized into two easily computable conditions. The proposed framework can be applied to various populations for studying the viability of herd immunity strategies against COVID-19. For Japan, herd immunity may be developed by the proposed scheme if $${\mathcal {R}}_0 \le 2.0$$
R
0
≤
2.0
and the severity rates of the disease are 1/10 times smaller than the previously reported value, although as high mortality as seasonal influenza is expected.
This study proposes a prototype quantitative method for dynamic revenue management of a private toll road, taking into account the long-term dynamics of transportation demand. This is first formulated as a stochastic singular control problem, in which the manager can choose the toll level from two discrete values. Each toll change requires nonnegative adjustment costs. Our analysis then reveals that the optimality condition reduces to standard linear complementarity problems, by using certain function transformation techniques. This enables us to develop an efficient algorithm for solving the problem, exploiting the recent advances in the theory of complementarity problems. Copyright Springer Science + Business Media, LLC 2006Toll road projects, Dynamic revenue management, Transportation demand uncertainty, Stochastic singular control, Generalized complementarity problem,
In this study, we analyzed the actual amount of gasoline transported into the Tohoku region during the first month after the Great East Japan Earthquake. We found that: (1) the amount of gasoline supplied in the Tohoku region during the first two weeks was only 1/3 of the normal demand; (2) the shortage of supply in the first two weeks led to a huge "back-log of demand"; (3) it took four weeks for the backlog to be cleared and the lost (suppressed) demand during the period was equivalent to the amount of normal demand for 7 days; (4) the gaps between gasoline supply and demand in the Pacific coast areas were huge, compared with those in the Japan sea coast areas, while the gap in each prefecture of the Tohoku region was gradually reduced over time in the following order: Akita, Aomori, Iwate, Yamagata, and finally, Miyagi prefecture.
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