ABSTRACT
We consider online resource allocation under a typical nonprofit setting, where limited or even scarce resources are administered by a not-for-profit organization like a government. We focus on the internal-equity by assuming that arriving requesters are homogeneous in terms of their external factors like demands but heterogeneous for their internal attributes like demographics. Specifically, we associate each arriving requester with one or several groups based on their demographics (i.e., race, gender, and age), and we aim to design an equitable distributing strategy such that every group of requesters can receive a fair share of resources proportional to a preset target ratio. We present two LP-based sampling algorithms and investigate them both theoretically (in terms of competitive-ratio analysis) and experimentally based on real COVID-19 vaccination data maintained by the Minnesota Department of Health. Both theoretical and numerical results show that our LP-based sampling strategies can effectively promote equity, especially when the arrival population is disproportionately represented, as observed in the early stage of the COVID-19 vaccine rollout.
ABSTRACT
AIM: To study the effect of intensive online courses on myopia in primary and middle school students with orthokeratology-lens during Corona Virus Disease 2019 (COVID-19) epidemic. METHODS: A total of 77 children in myopia with orthokeratology lens in outpatients from February to August 2020 were included in the study. Take a questionnaire to statistics times spending on online course, school class, playing digital electronic good, outdoor activity, homework, sleeping during the COVID-19 epidemic and school time, and analyze the differences of axial length(AL) variation between the COVID-19 epidemic and school time. RESULTS: For elementary school students, the time spending on online course and school class were 2.69±1.02h and 4.07±0.78h per day respectively (P<0.001), 6.67±1.82h and 6.31±1.19h per day were spent on short-distance use of eyes during the COVID-19 period and school time, respectively (P<0.001). For middle school students, the time spending on online course and school class were 4.35±1.59h and 6.33±0.66h per day respectively (P<0.001), 9.19±2.46h and 7.85±0.81h per day were spent on short-distance use of eyes (P=0.010) during the COVID-19 period and school time, respectively. For elementary school students, the average increase of right eye AL were 0.15±0.09mm and 0.06±0.06mm (P<0.001), the increase of left eye AL were 0.12±0.16mm and 0.07±0.09mm (P=0.048) during the COVID-19 period and school time, respectively. For middle school students, the average increase of right eye were AL 0.08±0.08mm and 0.05±0.05mm (P=0.242), and the average increase of left eye AL were 0.13±0.09mm and 0.04±0.06mm (P<0.001) during the COVID-19 period and school time, respectively. The results showed that both the time of short-distance use of digital electronic product and totally time on close visual study increased significantly during the epidemic period, the growth of AL was faster than that in school time, and the myopia increased rapidly. CONCLUSION: During the COVID-19 epidemic, intensive online lessons resulted in the time of short-distance use of digital electronic product increase significantly. Meanwhile, the AL growth accelerates significantly compared with that during school time and finally lead to myopia increased. Copyright 2021 by the IJO Press.