In this paper, we study the path based continuous spatial keyword queries, which find the answer set continuously when the query point moves on a given path. Under this setting, we explore two primitive spatial keyword queries, namely k nearest neighbor query and range query. The technical challenges lie in that: retrieving qualified vertices in large road networks efficiently, and issuing the query continuously for points on the path, which turns out to be inapplicable. To overcome the above challenges, we (...) first propose a backbone road network index structure, which supports the distance computation efficiently and offers a global insights of the whole road network. Motivated by the safe zone technique, we then transform our queries to the issue of finding event points, which capture the changes of answer set. By this transformation, our queries are to be simple and feasible. To answer the queries, we propose a Two-Phase Progressive computing framework, which first computes the answer sets for some crucial vertices on the path, and then identifies the event points by the retrieved answer sets. Extensive experiments on both real and synthetic data sets are conducted to evaluate the performance of our proposed algorithms, and the results show that our algorithms outperform competitors by several orders of magnitude. (shrink)

Background: In China, celebrities, represented by entertainment and sports personalities, are often involved in charitable activities to assist the party-state in solving social problems. Although previous research has addressed the manifestation of prosocial behavior by Chinese celebrities, altruistic engagements have rarely been theorized from the perspective of impression management.Methods: Based on the perspective of impression management, we use the discourse analysis approach to analyze the interview manuscripts of Chinese celebrities in media reports and then summarize the charitable motives and impression (...) management strategies adopted by Chinese celebrities in their self-presentation.Results: Chinese celebrities’ self-presentation of philanthropic motives in the media can be roughly divided into five categories: motivation for empathy-altruism, motivation for social responsibility, motivation to gain prestige, and pursue fame, motivation to reduce negative emotions, and motivation to achieve fulfillment and satisfaction. The philanthropic motives presented in media reports include the impression management processes of celebrities. They adopt a variety of image management strategies to self-present their philanthropic motives, and sometimes several strategies coexist.Conclusion: Our paper helps to expand the existing understanding of the relationship between impression management and philanthropy. The presentation of Chinese celebrities’ philanthropic motivations in the media reflects the uniqueness of China’s political, institutional, and social environment in influencing celebrity philanthropy. As a philanthropic phenomenon with Chinese characteristics, this study could provide some insights into the understanding of celebrities and philanthropy in other cultural contexts. (shrink)

The quality of service of a user in user-centric unmanned aerial vehicle group is degraded by complex cochannel interference; hence, a cooperative game power control algorithm in UUAVG is proposed. The algorithm helps to establish a downlink power control model of the UUAVG, construct a product of the signal to interference noise ratio function of each user as a utility function of the cooperative game, and deduce the optimal power control scheme using the Lagrange function. This scheme reduces the interference (...) of the service unmanned aerial vehicle to edge users and improves the communication quality of all the users as well as the throughput of the entire system. Simulation results show that the average throughput of the CGPC algorithm improved by 10.32% compared with the traditional Stackelberg Game based Nonunified Pricing Power Control algorithm. This shows that the CGPC algorithm can effectively reduce the transmission power of the cooperative UAV and enhance the capacity of the entire system, ensuring communication quality. (shrink)