Purpose

The emergence of a coronavirus disease 2019 (COVID-19) epidemic has had a tremendous impact on the world, and the characteristics of its evolution need to be better understood.

Design/methodology/approach

To explore the changes of cases and control them effectively, this paper analyzes and models the fluctuation and dynamic characteristics of the daily growth rate based on the data of newly confirmed cases around the world. Based on the data, the authors identify the inflection points and analyze the causes of the new daily confirmed cases and deaths worldwide.

Findings

The study found that the growth sequence of the number of new confirmed COVID-19 cases per day has a significant cluster of fluctuations. The impact of previous fluctuations in the future is gradually attenuated and shows a relatively gentle long-term downward trend. There are four inflection points in the global time series of new confirmed cases and the number of deaths per day. And these inflection points show the state of an accelerated rise, a slowdown in the rate of decline, a slowdown in the rate of growth and an accelerated decline in turn.

Originality/value

This paper has a certain guiding and innovative significance for the dynamic research of COVID-19 cases in the world.

中文翻译：

---

全球COVID-19病例波动特征及拐点识别

目的

2019 年冠状病毒病 (COVID-19) 流行病的出现对世界产生了巨大影响，需要更好地了解其演变特征。

设计/方法/方法

为探索病例变化并有效控制病例变化，本文以全球新确诊病例数据为基础，对日增长率的波动和动态特征进行分析和建模。根据这些数据，作者确定了拐点，并分析了全球每日新增确诊病例和死亡病例的原因。

发现

研究发现，每天新增确诊的 COVID-19 病例数的增长序列具有显着的集群波动。前期波动对未来的影响逐渐减弱，呈现相对温和的长期下行趋势。全球新增确诊病例和每日死亡人数的时间序列有四个拐点。而这些拐点又依次呈现出加速上升、下降速度放缓、增速放缓和加速下降的状态。

原创性/价值

该论文对全球COVID-19病例动态研究具有一定的指导和创新意义。