Subjects: Library Science，Information Science >> Information Science submitted time 2023-07-20
Abstract： [Purpose/Significance] The study aims to explore the construction of a social group information behavior and public opinion topic graph during significant emergencies. This research helps to better understand the evolution of public opinion during such events and identify sensitive public opinion topics. By doing so, it enables positive public opinion guidance, which plays a crucial role in emergency response and maintaining social stability. [Method/Process] This paper utilizes Latent Dirichlet Allocation (LDA) to construct a graph for the clustering and evolution of public opinion topics related to social group information behavior. Additionally, it builds a graph depicting the evolution of public opinion topic popularity based on temporal characteristics. Lastly, it constructs a graph illustrating the evolution of public opinion topic paths based on similarity. Furthermore, a process model for constructing the social group information behavior and public opinion topic graph during significant emergencies is presented. [Result/Conclusion] The research results indicate that the proposed analysis model for public opinion topics during significant emergencies effectively analyzes the characteristics of public opinion topics related to social group information behavior on social media. It also identifies factors influencing the popularity of these topics and identifies optimal paths for topic diffusion. This study provides a new theoretical framework and analysis methods for analyzing social group information behavior and public opinion during significant emergencies. It also offers valuable insights for guiding online public opinion and public opinion governance during such events.
Peer Review Status:
Awaiting Review
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Under the background of global warming, permafrost on the Qinghai-Tibet Plateau has been experienced a significant degradation, which may have effects on regional climate, hydrological and ecological processes. Based on long-term observation data in permafrost region of Qinghai-Tibet Plateau and reanalysis data, the variation characteristics of temperature and precipitation in permafrost region in recent ten years were analyzed, and the variation trends of active layer thickness, ground temperature and soil water content were examined in this study. The spatial and temporal distribution of precipitation and soil water content in permafrost region from 1980 to 2018 were presented. The results showed that the permafrost in different regions on the Qinghai-Tibet Plateau has changed significantly in the past ten years. The thickness of the active layer and the ground temperature has increased, and the soil water content at the bottom of the active layer has increased. At the regional scale, the precipitation and soil water content in permafrost region increased significantly from 1980 to 2018. The possible impacts of permafrost degradation on hydrological processes, lake area changes and surface deformation were discussed. The results are helpful to understand the impact of permafrost changes on regional environment, deepen our understanding of the mechanisms of the interaction between permafrost and water cycle, and provide a scientific basis for environmental protection, engineering design and construction in cold regions.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2018-03-16
Abstract：根据移栽蔬菜田间锄草作业工况和要求，基于视觉伺服控制技术，设计了电驱锄草机器人系统。该系统以中小功率拖拉机为配套动力，由伺服电动机驱动月牙形锄草刀护苗锄草和对行，减少了能耗与污染物排放，提高了系统伺服特性。机器视觉系统实时采集田间图像并处理，对作物进行识别与定位。控制器结合视觉系统获取的刀苗距、锄草机器人前进速度、锄刀相位角度及机器人横向偏差信息，利用智能伺服驱动器精确控制锄草刀避苗和对行。试验表明，在前进速度不高于1.5km/h、作物株距不小于0.35m工况下，伤苗率小于10%，田间杂草锄净率约为90%。
Peer Review Status:Awaiting Review
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