A data model and algorithms for a spatial data marketplace     

Mahmoud Sakr 《International journal of geographical information science》2018,32(11):2140-2168

A data marketplace is a platform that facilitates online data trading. It gives sellers the capabilities of publishing data, defining the price function, the authorization rules and the data contract. It gives customers the capabilities to search for data services, to query for their price, to invoke them and to pay for the usage. As data are more and more emphasized as a payable asset, the need for data marketplaces rises. There is a lack of marketplace proposals for spatial data. This paper contributes to fill-in this gap. We propose a data model for representing the different types of data involved. The logical representation of data is a quadtree, and the physical representation fits into a key-value store. The model is thus logically simple and extensible, and physically scalable and highly available. We discuss price queries in detail and propose evaluation algorithms.  相似文献   

Spatiotemporal patterns of the daily relative risk of COVID-19 in China     

CHENG Changxiu  JIANG Yifan  SONG Changqing  SHEN Shi  WU Yunfeng  ZHANG Tianyuan 《地理学报(英文版)》2021,31(7):1039-1058

The coronavirus disease 2019(COVID-19) pandemic continues to threaten lives and the economy around the world. Estimating the risk of COVID-19 can help in predicting spreading trends, identifying risk areas, and making public health decisions. In this study, we proposed a comparative risk assessment method to estimate comprehensive and dynamic COVID-19 risks by considering the pandemic severity and the healthcare system pressure and then employing the z-order curve and fractal theory. We took the COVID-19 cases from January 19–March 10, 2020 in China as our research object. The results and analysis revealed that(1) the proposed method demonstrated its feasibility to assess and illustrate pandemic risk;(2) the temporal patterns of the daily relative risk indices of 31 provinces were clustered into four groups(high-value, fluctuating-increase, inverted U-shaped, and low-stable);(3) the spatial distribution of the relative pandemic risk indicated a significant circular pattern centered on Hubei Province; and(4) healthcare system capacity is the key to reducing relative pandemic risk, and cases imported from abroad should be given more attention. The methods and results of this study will provide a methodological basis and practical guidance for regional pandemic risk assessment and public health decision-making.  相似文献