C-Watcher: A Framework for Early Detection of High-Risk Neighborhoods Ahead of COVID-19 Outbreak

The novel coronavirus disease (COVID-19) has crushed daily routines and is still rampaging through the world. Existing solution for nonpharmaceutical interventions usually needs to timely and precisely select a subset of residential urban areas for containment or even quarantine, where the spatial distribution of confirmed cases has been considered as a key criterion for the subset selection. While such containment measure has successfully stopped or slowed down the spread of COVID-19 in some countries, it is criticized for being inefficient or ineffective, as the statistics of confirmed cases are usually time-delayed and coarse-grained. To tackle the issues, we propose C-Watcher, a novel data-driven framework that aims at screening every neighborhood in a target city and predicting infection risks, prior to the spread of COVID-19 from epicenters to the city. In terms of design, C-Watcher collects large-scale long-term human mobility data from Baidu Maps, then characterizes every residential neighborhood in the city using a set of features based on urban mobility patterns. Furthermore, to transfer the firsthand knowledge (witted in epicenters) to the target city before local outbreaks, we adopt a novel adversarial encoder framework to learn "city-invariant" representations from the mobility-related features for precise early detection of high-risk neighborhoods, even before any confirmed cases known, in the target city. We carried out extensive experiments on C-Watcher using the real-data records in the early stage of COVID-19 outbreaks, where the results demonstrate the efficiency and effectiveness of C-Watcher for early detection of high-risk neighborhoods from a large number of cities.Comment: 11 pages, accepted by AAAI 2021, appendix is include

Evaluation of landscape ecological risk in key ecological functional zone of South–to–North Water Diversion Project, China

The key ecological functional zone plays a significant role in maintaining ecosystem security, water conservation function and environmental protection. However, owing to rapid industrialization and urbanization, some ecological functional zones have undergone great changes in land use, which has changed the landscape pattern characteristics and resulted in ecological risks, affecting the regional ecological environment and water security. In this study, the core water source area of the Middle Route of China’s South–to–North Water Diversion Project is selected as the case study. A regional landscape ecological risk index (ERI) was constructed to evaluate the landscape ecological risk driven by land use transformation. Moreover, the ERI's spatiotemporal characteristics were investigated using a combination of geographic information systems and geostatistical techniques, which reveal the dominant land use function types associated with ecological risks and their causes. We found that (1) there was not a notable shift in land use, and the level of ecological risk increased slightly from 2010 to 2015. The conversion of previously unproductive land into places for industrial production land and agricultural productive land played a significant role in this phenomenon. From 2015 to 2020, the Danjiangkou Reservoir officially started operation. Furthermore, the improvement of residents’ awareness of environmental protection and natural forest land significantly reduced the ecological risk. (2) The ecological risk has a strong positive autocorrelation, exhibiting a pattern of high in the east and center, low in the west and periphery. (3) An obvious corresponding relation exists between the impacts of topography, soil, and climate on patterns of land use and ecological risk. Additionally, the strict ecological protection policies implemented by the Chinese government have realized remarkable achievements in promoting the improvement of ecological risks. Our study can provide a decision–making basis for the local authorities to conduct ecological risk prevention activities and ensure the sustainable northward flow of clean water