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Xinwei Chai

Publications and source records attributed to Xinwei Chai.

2 recordsLinked to original sources

Analysis of Spatial-temporal Behavior Pattern of the Share Bike Usage during COVID-19 Pandemic in Beijing

During the epidemics of COVID-19, the whole world is experiencing a serious crisis on public health and economy. Understanding human mobility during the pandemic helps one to design intervention strategies and resilience measures. The widely used Bike Sharing System (BSS) can characterize the activities of urban dwellers over time & space in big cities but is rarely reported in epidemiological research. In this paper, we present a human mobility analyzing framework} based on BSS data, which examines the spatiotemporal characteristics of share bike users, detects the key time nodes of different pandemic stages, and demonstrats the evolution of human mobility due to the onset of the COVID-19 threat and administrative restrictions. We assessed the net impact of the pandemic by using the result of co-location analysis between share bike usage and POIs (Point Of Interest). Our results show the pandemic reduced the overall bike usage by 64.8%, then an average increase (15.9%) in share bike usage appeared afterwards, suggesting that productive and residential activities have partially recovered but far from the ordinary days. These findings could be a reference for epidemiological researches and inform policymaking in the context of the current COVID-19 outbreak and other epidemic events at city-scale.

physics.soc-ph

A Heuristic for Reachability Problem in Asynchronous Binary Automata Networks

On demand of efficient reachability analysis due to the inevitable complexity of large-scale biological models, this paper is dedicated to a novel approach: PermReach, for reachability problem of our new framework, Asynchronous Binary Automata Networks (ABAN). ABAN is an expressive modeling framework which contains all the dynamics behaviors performed by Asynchronous Boolean Networks. Compared to Boolean Networks (BN), ABAN has a finer description of state transitions (from a local state to another, instead of symmetric Boolean functions). To analyze the reachability properties on large-scale models (like the ones from systems biology), previous works exhibited an efficient abstraction technique called Local Causality Graph (LCG). However, this technique may be not conclusive. Our contribution here is to extend these results by tackling those complex intractable cases via a heuristic technique. To validate our method, tests were conducted in large biological networks, showing that our method is more conclusive than existing ones.

cs.FL