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The Impacts of Mass Media on Contemporary British Politics
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作者 吴艳华 《科技信息》 2010年第24期I0162-I0162,I0166,共2页
Currently the mass media possess a great deal of influences in society and politics.The mass media have a powerful influence on politics.This paper will mainly analyze the impacts of mass media on three aspects of pol... Currently the mass media possess a great deal of influences in society and politics.The mass media have a powerful influence on politics.This paper will mainly analyze the impacts of mass media on three aspects of political life and behaviors in Britain. 展开更多
关键词 英语 大众传媒 社会 影响力
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The Impact of Haze Weather on Health: A view to Future 被引量:15
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作者 LU Kai QIN Yu +1 位作者 HE Guang Xue George F.GAO 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2013年第12期945-946,共2页
In January 2013, China suffered large-scale haze weather four times, affecting 30 cities in all. The average number of haze weather days in many regions was higher than the same period in every year since 1961. PM2.s,... In January 2013, China suffered large-scale haze weather four times, affecting 30 cities in all. The average number of haze weather days in many regions was higher than the same period in every year since 1961. PM2.s, which is defined as fine particulate matter with an aerodynamic diameter of 2.5 micrometers or less, is the main health hazard in the context of haze weather. It can carry large amounts of poisonous and harmful substances, and penetrate deep into the lungs and blood circulation through the respiratory tract, thereby affecting human health. 展开更多
关键词 HAZE A view to Future the impact of Haze Weather on Health
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Health Providers’ Points of View on the Impact of the Project to Strengthen the Expanded Program of Routine Vaccination from 2014 to 2018 in the Barumbu Health Zone in Kinshasa, Democratic Republic of Congo
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作者 Ngoyi Kankiesa Nestor Milambo Kapia Patrick +6 位作者 Bope Kwete Minga Barthélémy Pembi Pembi Francy Muanyim Bope Pierre Nkumbi Malu Jeaont Tshiama Kabongo Elysée Sabuli Sewa Alexis Kafinga Luzolo Emery 《Journal of Biosciences and Medicines》 CAS 2022年第8期143-152,共10页
According to the World Health Organization, approximately 3 million deaths are prevented each year in the world thanks to vaccination and then, in addition, each year, it makes it possible to avoid nearly 750,000 chil... According to the World Health Organization, approximately 3 million deaths are prevented each year in the world thanks to vaccination and then, in addition, each year, it makes it possible to avoid nearly 750,000 children suffering from serious physical, mental or neurological handicaps and 1.5 million other deaths could be avoided if the vaccination coverage is improved. However, vaccination coverage is often not achieved due to various difficulties encountered by health providers in the expanded program on vaccination activities. Yet, it is important to strengthen the program. This research paper aimed to assess health providers’ points of view on the impact of the project to strengthen the routine expanded program on vaccination in the Barumbu health zone in Kinshasa, Democratic Republic of Congo (RDC). To do so, we surveyed a convenience sample of 234 health providers involved in the implementation of the project, including 210 community relays, 9 permanent nurses, 9 health committee chairpersons and 6 health authorities. A questionnaire related to the objective of the research was submitted to them. After analyzing the data, we found that the points of view of health providers are negative. The performance of the vaccination program was not great. Several reasons were given for this, including the non-involvement of the political and administrative authorities, the failure to respect the funds disbursement circuit and the non-effective financing of vaccination activities in the Barumbu health zone in Kinshasa, DRC. 展开更多
关键词 Point of view Health Providers impact Strengthening Project Routine Vaccination
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An Analysis of Fragmented Reading and Its Social Impact on College Students in the Era of New Media
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作者 Weiguo Xie 《Journal of Contemporary Educational Research》 2019年第3期33-37,共5页
In the era of new media,people’s lifestyle,education and the like are inseparable from the Internet.At the same time,due to the emergence of smart devices such as mobile phones and tablet computers,people’s reading ... In the era of new media,people’s lifestyle,education and the like are inseparable from the Internet.At the same time,due to the emergence of smart devices such as mobile phones and tablet computers,people’s reading habits have changed.Fragmented reading has become an important form of reading for college students.College students themselves have the strong ability to accept change,so fragmented reading has gradually become an important form of student learning.This paper mainly analyses fragmented reading by college students and its impact on society in the era of new media. 展开更多
关键词 ERA of new media COLLEGE STUDENTS fragmented READING SOCIAL impact
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Modelling the preventive treatment under media impact on tuberculosis:A comparison in four regions of China
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作者 Jun Zhang Yasuhiro Takeuchi +1 位作者 Yueping Dong Zhihang Peng 《Infectious Disease Modelling》 CSCD 2024年第2期483-500,共18页
Preventive treatment for people with latent Tuberculosis infection(LTBI)has aroused our great interest.In this paper,we propose and analyze a novel mathematical model of TB considering preventive treatment with media ... Preventive treatment for people with latent Tuberculosis infection(LTBI)has aroused our great interest.In this paper,we propose and analyze a novel mathematical model of TB considering preventive treatment with media impact.The basic reproduction number R_(0)is defined by the next generation matrix method.In the case without media impact,we prove that the disease-free equilibrium is globally asymptotically stable(unstable)if R_(0)<1(R_(0)>1).Furthermore,we obtain that a unique endemic equilibrium exists when R_(0)>1,which is globally asymptotically stable in the case of permanent immunity and no media impact.We fit the model to the newly reported TB cases data from 2009 to 2019 of four regions in China and estimate the parameters.And we estimatedR_(0)=0.5013<1 in Hubei indicating that TB in Hubei will be eliminated in the future.However,the estimatedR_(0)=1.015>1 in Henan,R_(0)=1.282>1 in Jiangxi and R_(0)=1.930>1 in Xinjiang imply that TB will continue to persist in these three regions without further prevention and control measures.Besides,sensitivity analysis is carried out to illustrate the role of model parameters for TB control.Our finding reveals that appropriately improving the rate of timely treatment for actively infected people and increasing the rate of individuals with LTBI seeking preventive treatment could achieve the goal of TB elimination.In addition,another interesting finding shows that media impact can only reduce the number of active infections to a limited extent,but cannot change the prevalence of TB. 展开更多
关键词 Latent tuberculosis infection Preventive treatment media impact Mathematical model Tuberculosis elimination
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Significance of Live Streaming in Shaping Business: A Critical Review and Analytical Study
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作者 Nasir Uddin 《Social Networking》 2024年第3期35-43,共9页
With the rise of live streaming on social media, platforms like Facebook, Instagram, and YouTube have become powerful business tools. They enable users to share live videos, fostering direct connections between busine... With the rise of live streaming on social media, platforms like Facebook, Instagram, and YouTube have become powerful business tools. They enable users to share live videos, fostering direct connections between businesses and their customers. This critical literature review paper explores the impact of live streaming on businesses, focusing on its role in attracting and satisfying consumers by promoting products tailored to their needs and wants. It emphasizes live streaming’s crucial role in engaging customers, a key to business growth. The study also provides viable strategies for businesses to leverage live streaming for growth and customer engagement, underscoring its importance in the business landscape. 展开更多
关键词 Live Streaming Social media Business impact Consumer Decision-Making Brand Community Interactive Marketing Facebook Live Instagram Live Product Reviews online Consumer Behavior Self-Determination theory (SDT) Live Video Marketing
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DYNAMIC STRESS FIELD AROUND THE MODE Ⅲ CRACK TIP IN AN ORTHOTROPIC FUNCTIONALLY GRADED MATERIAL
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作者 李春雨 邹振祝 段祝平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第6期651-658,共8页
The problem of a Griffith crack in an unbounded orthotropic functionally graded material subjected to antipole shear impact was studied. The shear moduli in two directions of the functionally graded material were assu... The problem of a Griffith crack in an unbounded orthotropic functionally graded material subjected to antipole shear impact was studied. The shear moduli in two directions of the functionally graded material were assumed to vary proportionately as definite gradient. By using integral transforms and dual integral equations, the local dynamic stress field was obtained. The results of dynamic stress intensity factor show that increasing shear moduli's gradient of FGM or increasing the shear modulus in direction perpendicular to crack surface can restrain the magnitude of dynamic stress intensity factor. 展开更多
关键词 anisotropic media functionally graded materials dynamic stress intensity factor CRACK impact
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Who should you be following? The top 100 social media influencers in orthopaedic surgery
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作者 Nathan H Varady Akash A Chandawarkar +1 位作者 Willem A Kernkamp Itai Gans 《World Journal of Orthopedics》 2019年第9期327-338,共12页
BACKGROUND Social media has been credited with the potential to transform medicine,and Twitter was recently named“an essential tool”for the academic surgeon.Despite this,peer-to-peer and educational influence on soc... BACKGROUND Social media has been credited with the potential to transform medicine,and Twitter was recently named“an essential tool”for the academic surgeon.Despite this,peer-to-peer and educational influence on social media has not been studied within orthopaedic surgery.This knowledge is important to identify who is controlling the conversation about orthopaedics to the public.We hypothesized that the plurality of top influencers would be sports medicine surgeons,that social media influence would not be disconnected from academic productivity,and that some of the top social media influencers in orthopaedic surgery would not be orthopaedic surgeons.AIM To identify the top 100 social media influencers within orthopaedics,characterize who they are,and relate their social media influence to academic influence.METHODS Twitter influence scores for the topic“orthopaedics”were collected in July 2018 using Right Relevance software.The accounts with the top influence scores were linked to individual names,and the account owners were characterized with respect to specialty,subspecialty,practice setting,location,board certification,and academic Hirsch index(h-index).RESULTS Seventy-eight percent of top influencers were orthopaedic surgeons.The most common locations included California(13%),Florida(8%),New York(7%),United Kingdom(7%),Colorado(6%),and Minnesota(6%).The mean academic h-index of the top influencers(n=79)was 13.67±4.12(mean±95%CI)and median 7(range 1-89)(median reported h-index of academic orthopaedic faculty is 5 and orthopaedic chairpersons is 13).Of the 78 orthopaedic surgeons,the most common subspecialties were sports medicine(54%),hand and upper extremity(18%),and spine(8%).Most influencers worked in private practice(53%),followed by academics(17%),privademics(14%),and hospital-based(9%).All eligible orthopaedic surgeons with publicly-verifiable board certification statuses were board-certified(n=74).CONCLUSION The top orthopaedic social media influencers on Twitter were predominantly board-certified,sports-medicine subspecialists working in private practice in the United States.Social media influence was highly concordant with academic productivity as measured by the academic h-index.Though the majority of influencers are orthopaedic surgeons,22%of top influencers on Twitter are not,which is important to identify given the potential for these individuals to influence patients’perceptions and expectations.This study also provides the top influencer network for other orthopaedic surgeons to engage with on social media to improve their own social media influence. 展开更多
关键词 SOCIAL media Influence impact TWITTER ORTHOPAEDICS ORTHOPEDICS
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Adaptive weighting impact angle optimal guidance law considering seeker's FOV angle constraints 被引量:7
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作者 LI Ran WEN Qiuqiu +1 位作者 TAN Wangchun ZHANG Yijie 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第1期142-151,共10页
In this paper, a new adaptive optimal guidance law with impact angle and seeker’s field-of-view(FOV) angle constraints is proposed. To this end, the generalized optimal guidance law is derived first. A changeable imp... In this paper, a new adaptive optimal guidance law with impact angle and seeker’s field-of-view(FOV) angle constraints is proposed. To this end, the generalized optimal guidance law is derived first. A changeable impact angle weighting(IAW) coefficient is introduced and used to modify the guidance law to make it adaptive for all guidance constraints. After integrating the closed-form solution of the guidance command with linearized engagement kinematics, the analytic predictive models of impact angle and FOV angle are built, and the available range of IAW corresponding to constraints is certain. Next, a calculation scheme is presented to acquire the real-time value of IAW during the entire guidance process. When applying the proposed guidance law, the IAW will keep small to avoid a trajectory climbing up to limit FOV angle at an initial time but will increase with the closing target to improve impact position and angle accuracy, thereby ensuring that the guidance law can juggle orders of guidance accuracy and constraints control. 展开更多
关键词 optimal guidance law impact angle constraint fieldof-view(FOV) angle constraint weighting coefficient
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Analysis of Social Networks among Students in Abidjan City
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作者 Aliou Bamba Aladji Kamagaté +1 位作者 Moussa Koivogui Douatia Koné 《Open Journal of Applied Sciences》 CAS 2022年第8期1339-1351,共13页
This paper investigates the social networks usage by students in Abidjan city, C&ocirc;te d’Ivoire. We focus on a descriptive or quantitative analysis to understand the motivations and how students make use of in... This paper investigates the social networks usage by students in Abidjan city, C&ocirc;te d’Ivoire. We focus on a descriptive or quantitative analysis to understand the motivations and how students make use of internet and social networks. More than six hundred forms were distributed to persons we have deemed as students. In return, we received more than 93% of the forms that have been processed. The study highlights the materials and the digital platforms that students used the most. The majority of the respondents reported to have access to the social networks in their mobile phones, with WhatsApp leading this application ranking, followed by Instagram, Facebook, YouTube, and Tik Tok. The survey shows that two third of our respondents are aged from 19 to 25 years old and almost half of the respondents spend daily 2 to 5 hours on digital platforms. The investigation also reveals that the main online activities are the e-commerce, chatting, information, and entertainment. The paper addresses also the online harassment of the students and it shows that more than one tenth of them have been victims of cyber-bullying. This study might be useful for governments, institutions, academia, individuals and professionals in order to communicate efficiently with a given population for a better use of social networks and to prevent students from harassment. 展开更多
关键词 Social Network Social media Applications Network Structure view Status Structure view STATISTICS Digital Platforms online Harassment
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Social media in cardiology:Reasons to learn how to use it
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作者 Rafael Vidal-Perez Jose Juan Gómez de Diego +2 位作者 Julia Grapsa Ricardo Fontes-Carvalho Jose Ramon Gonzalez-Juanatey 《World Journal of Cardiology》 2019年第10期217-220,共4页
Social media has changed the way we learn,educate,and interact with our peers.The dynamic nature of social media and their immediate availability through our portable devices(smartphones,tablets,smartwatches,etc.)is q... Social media has changed the way we learn,educate,and interact with our peers.The dynamic nature of social media and their immediate availability through our portable devices(smartphones,tablets,smartwatches,etc.)is quickly transforming the way we participate in society.The scope of these digital tools is broad as they deal with many different aspects:Teaching and learning,case discussion,congresses coverage,peer to peer interaction,research are examples worth mentioning.The scientific societies considered more innovative,are promoting these tools between their members.These new concepts need to be known by the cardiologists to stay updated,as countless information is moving rapidly through these channels.We summarize the main reasons why learning how to use these tools to be part of the conversation is essential for the cardiologist in training or fully stablished. 展开更多
关键词 Social media CARDIOLOGY ConGRESS Learning Teaching Interaction Cardiovascular diseases impact Factor Portable devices SMARTPHonE TABLET
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A Full View Video Navigation System
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作者 ZHANG Fang 《电脑知识与技术》 2010年第12期9839-9841,共3页
This paper presents a full view video navigation platform and the approach to buildup such a platform.Unlike the traditional full view navigation system,which always bases on image panorama,our system is based on full... This paper presents a full view video navigation platform and the approach to buildup such a platform.Unlike the traditional full view navigation system,which always bases on image panorama,our system is based on full view video created by video mosaics.Neither the current concept of video mosaics,which means posting together video frames to get a wide view,while these frames are from the same video.Video mosaics in this paper mean stitching different videos together to get a full view video.Videos,together recording 360° of the scenery,are captured through a certain route by digital cameras arranged in a circle around the view point.Then break up these videos into frame sequence.Frame coming from different videos with the same timestamp are stitched into a panoramic image.Consider these panoramic images as frames;montage these panoramic frames into a full view video,by sequence of time.While displaying the full view video people could decide to go forward,or stop to see around,or proceed in a certain direction.While talking about full view navigation,we are mostly talking about image-based cylindrical or spherical panorama [2].One way to create such a panorama is,after a series of translation,stitching together a group of images taken by panning camera [1].Each of these images presents part of the scene and with certain degrees of overlap to adjacent ones.After stitching,we get a panorama image with width is much bigger than the raw images,map it onto a cylinder or sphere surface is a better way to show it.The mapped one is called cylindrical panorama or spherical panorama.While navigating,taking sphere panorama as an example,people were supposed to standing at the center of the sphere,by rotating the sphere,different view coming into eyes.This kind of navigation makes people feel as the same as standing in the real world.But one limitation is that the step is stuck to one point,could see around but not move forward or back(there is moving forward and back by zooming in and zooming out respectively,but it's not truly move).In our work,videos are used as the stitching source instead of images.Video,or could say a sequence of images taken at continuous view point(actually it is the definition of 'video',and is the saying we are going to take advantage of in this paper),are captured by a camera circle,and are stitched into a full view video.Frames coming from different video with the same timestamp are stitched into a panorama frame.Transform the processed panorama frames into a video. 展开更多
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Rapid estimation of an earthquake impact area using a spatial logistic growth model based on social media data 被引量:5
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作者 Yandong Wang Shisi Ruan +1 位作者 Teng Wang Mengling Qiao 《International Journal of Digital Earth》 SCIE EI 2019年第11期1265-1284,共20页
Rapid estimates of impact areas following large earthquakes constitute the cornerstone of emergency response scenarios.However,collecting information through traditional practices usually requires a large amount of ma... Rapid estimates of impact areas following large earthquakes constitute the cornerstone of emergency response scenarios.However,collecting information through traditional practices usually requires a large amount of manpower and material resources,slowing the response time.Social media has emerged as a source of real-time‘citizen-sensor data’for disasters and can thus contribute to the rapid acquisition of disaster information.This paper proposes an approach to quickly estimate the impact area following a large earthquake via social media.Specifically,a spatial logistic growth model(SLGM)is proposed to describe the spatial growth of citizen-sensor data influenced by the earthquake impact strength after an earthquake;a framework is then developed to estimate the earthquake impact area by combining social media data and other auxiliary data based on the SLGM.The reliability of our approach is demonstrated in two earthquake cases by comparing the detected areas with official intensity maps,and the time sensitivity of the social media data in the SLGM is discussed.The results illustrate that our approach can effectively estimate the earthquake impact area.We verify the external validity of our model across other earthquake events and provide further insights into extracting more valuable earthquake information using social media. 展开更多
关键词 Social media EARTHQUAKE citizen-sensor data impact area spatial logistic growth model
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Disaster Impacts Surveillance from Social Media with Topic Modeling and Feature Extraction: Case of Hurricane Harvey 被引量:3
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作者 Volodymyr V.Mihunov Navid H.Jafari +2 位作者 Kejin Wang Nina S.N.Lam Dylan Govender 《International Journal of Disaster Risk Science》 SCIE CSCD 2022年第5期729-742,共14页
Twitter can supply useful information on infrastructure impacts to the emergency managers during major disasters,but it is time consuming to filter through many irrelevant tweets.Previous studies have identified the t... Twitter can supply useful information on infrastructure impacts to the emergency managers during major disasters,but it is time consuming to filter through many irrelevant tweets.Previous studies have identified the types of messages that can be found on social media during disasters,but few solutions have been proposed to efficiently extract useful ones.We present a framework that can be applied in a timely manner to provide disaster impact information sourced from social media.The framework is tested on a well-studied and data-rich case of Hurricane Harvey.The procedures consist of filtering the raw Twitter data based on keywords,location,and tweet attributes,and then applying the latent Dirichlet allocation(LDA) to separate the tweets from the disaster affected area into categories(topics) useful to emergency managers.The LDA revealed that out of 24 topics found in the data,nine were directly related to disaster impacts-for example,outages,closures,flooded roads,and damaged infrastructure.Features such as frequent hashtags,mentions,URLs,and useful images were then extracted and analyzed.The relevant tweets,along with useful images,were correlated at the county level with flood depth,distributed disaster aid(damage),and population density.Significant correlations were found between the nine relevant topics and population density but not flood depth and damage,suggesting that more research into the suitability of social media data for disaster impacts modeling is needed.The results from this study provide baseline information for such efforts in the future. 展开更多
关键词 Disaster impacts Hurricane Harvey Infrastructure impacts Latent Dirichlet allocation(LDA) Social media analysis Twitter data
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MIND THE GAP: TOWARDS AND BEYOND IMPACT MESSAGING TO ENHANCE TROPICAL CYCLONE RISK COMMUNICATION 被引量:1
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作者 PETER OTTO AMISHA MEHTA BROOKE LIU 《Tropical Cyclone Research and Review》 2018年第2期140-151,共12页
Traditionally, meteorological agencies collect, analyse, and share technical information about natural hazards with emergency services organisations and community members; often sending different warning products to e... Traditionally, meteorological agencies collect, analyse, and share technical information about natural hazards with emergency services organisations and community members; often sending different warning products to each of these groups. For the general public, effective risk communication requires that technical information be translated to first gain attention and build understanding of risk, and then continue to be exchanged by all parties. The World Meteorological Organization and its partner agencies have recognised this need for translated information by moving away from warnings describing risks solely in terms of meteorological parameters and towards clearer messaging emphasizing significance and potential impacts. While the move towards more relatable weather warning messaging is a positive one, risk communication is a complex, dynamic and interactive process that is highly dependent on audience psychology, knowledge, skills, and capabilities; presenting at once difficulties and opportunities for agencies. Over recent years, advertisers, politicians and public safety advocates have all improved their messaging through the use of big data, psychology, social networking and behavioural economics principles, yet the links between these elements and weather risk communication are still relatively immature. This report aims to build links between weather forecasters, social scientists and related industries by outlining three conceptual models social scientists have developed to meet different challenges in the field of risk communication; the mental models approach, risk information seeking and processing, and the protective action decision making model. Recent issues and successes in the communication of tropical cyclone risk will then be examined and compared to these models, and future opportunities will be discussed. 展开更多
关键词 RISK COMMUNICATIon impact-based WARNINGS impact WARNINGS tropical cyclone RISK MESSAGING models of RISK COMMUNICATIon public safety social media
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Public Reaction to Scientific Research via Twitter Sentiment Prediction
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作者 Murtuza Shahzad Hamed Alhoori 《Journal of Data and Information Science》 CSCD 2022年第1期97-124,共28页
Purpose:Social media users share their ideas,thoughts,and emotions with other users.However,it is not clear how online users would respond to new re search outcomes.This study aims to predict the nature of the emotion... Purpose:Social media users share their ideas,thoughts,and emotions with other users.However,it is not clear how online users would respond to new re search outcomes.This study aims to predict the nature of the emotions expressed by Twitter users toward scientific publications.Additionally,we investigate what features of the research articles help in such prediction.Identifying the sentiments of research articles on social media will help scientists gauge a new societal impact of their research articles.Design/methodology/appro ach:Several tools are used for sentiment analysis,so we applied five sentiment analysis tools to check which are suitable for capturing a tweet’s sentiment value and decided to use NLTK VADER and TextBlob.We segregated the sentiment value into negative,positive,and neutral.We measure the mean and median of tweets’sentiment value for research articles with more than one tweet.We next built machine learning models to predict the sentiments of tweets related to scientific publications and investigated the essential features that controlled the prediction models.Findings:We found that the most important feature in all the models was the sentiment of the research article title followed by the author count.We observed that the tree-based models performed better than other classification models,with Random Forest achieving 89%accuracy for binary clas sification and 73%accuracy for three-label clas sification.Research limitations:In this research,we used state-of-the-art sentiment analysis libraries.However,these libraries might vary at times in their sentiment prediction behavior.Tweet sentiment may be influenced by a multitude of circumstances and is not always immediately tied to the paper’s details.In the future,we intend to broaden the scope of our research by employing word2 vec models.Practical implications:Many studies have focused on understanding the impact of science on scientists or how science communicators can improve their outcomes.Research in this area has relied on fewer and more limited measures,such as citations and user studies with small datasets.There is currently a critical need to find novel methods to quantify and evaluate the broader impact of research.This study will help scientists better comprehend the emotional impact of their work.Additionally,the value of understanding the public’s interest and reactions helps science communicators identify effective ways to engage with the public and build positive connections between scientific communities and the public.Originality/value:This study will extend work on public engagement with science,sociology of science,and computational social science.It will enable researchers to identify areas in which there is a gap between public and expert understanding and provide strategies by which this gap can be bridged. 展开更多
关键词 Sentiment analysis Social media TWITTER Emotional impact Public understanding of science Science and technology studies
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有限视场下的攻击时间和角度多约束制导律 被引量:2
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作者 王江 刘经纬 +1 位作者 崔晓曦 范卫鹏 《北京理工大学学报》 EI CAS CSCD 北大核心 2024年第1期18-27,共10页
针对精确打击任务存在导引头视场受限这一过程约束的制导问题,提出了一种考虑视场限制以及攻击角度和时间多种约束的制导律.首先,在以比例导引项实现精确命中的基础上,利用最优控制理论,采用弹目距离加权控制能耗形式的指标函数,设计了... 针对精确打击任务存在导引头视场受限这一过程约束的制导问题,提出了一种考虑视场限制以及攻击角度和时间多种约束的制导律.首先,在以比例导引项实现精确命中的基础上,利用最优控制理论,采用弹目距离加权控制能耗形式的指标函数,设计了攻击角度控制项,并推导了相应的剩余飞行时间解析预测表达式.其次,基于最优误差动力学方法,设计了攻击时间相关的控制项,保证了攻击时间误差的有限时间收敛.同时,针对导引头视场有限的问题,分析了各控制项对前置角收敛性的影响,利用特定的限制函数确保前置角在整个制导过程中始终处于有效视场内,并给出了前置角的有界性及收敛性证明.数学仿真结果验证了所提出制导律对多约束制导问题的有效性. 展开更多
关键词 最优控制 攻击角度控制 攻击时间控制 视场约束 最优误差动力学
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Real Time Chatter Vibration Control System in High Speed Milling
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作者 Hyeok Kim Mun-Ho Cho +2 位作者 Jun-Yeong Koo Jong-Whan Lee Jeong-Suk Kim 《材料科学与工程(中英文A版)》 2015年第5期221-229,共9页
关键词 振动控制系统 高速铣削加工 实时控制 快速傅里叶变换 切削颤振 刀具寿命 切削条件 表面完整性
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刍议数字媒体艺术对动画创作的影响与变革 被引量:3
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作者 杨依依 《丝网印刷》 2024年第3期113-116,共4页
通过对数字媒体艺术表现手段的创新运用,使动画作品中呈现的各类造型表现更加精致,动作设计与表演更加精确,后期合成与特效设计更加全面,可以整体提高动画行业的艺术与技术质量水平。文章结合创作实践,探讨作为新兴业态的数字媒体艺术... 通过对数字媒体艺术表现手段的创新运用,使动画作品中呈现的各类造型表现更加精致,动作设计与表演更加精确,后期合成与特效设计更加全面,可以整体提高动画行业的艺术与技术质量水平。文章结合创作实践,探讨作为新兴业态的数字媒体艺术对动画创作产生的实质性影响与变革。 展开更多
关键词 数字媒体艺术 动画创作 影响与变革
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谁是对的人:社交媒体如何影响青年人的择偶观
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作者 聂静虹 左翊廷 郑汉卿 《中国地质大学学报(社会科学版)》 CSSCI 北大核心 2024年第4期143-156,共14页
青年是社交媒体中活跃的主角。社交媒体在成为青年主要信息获取渠道,便利他们生活的同时,也对他们的认知、态度和行为产生影响。择偶是青年日常生活中必不可少的需求,社交媒体的发展对青年择偶观的影响不容小觑。本研究主要探讨社交媒... 青年是社交媒体中活跃的主角。社交媒体在成为青年主要信息获取渠道,便利他们生活的同时,也对他们的认知、态度和行为产生影响。择偶是青年日常生活中必不可少的需求,社交媒体的发展对青年择偶观的影响不容小觑。本研究主要探讨社交媒体对青年择偶观的可能影响路径及具体机制。通过对29名青年用户的深度访谈发现,社交媒体对青年择偶观存在四种中观层面上的影响路径,分别为理解、定向、表达和娱乐。在微观层面上,单一社交媒体平台使用和跨社交媒体平台使用这两种不同的社交媒体使用行为,通过影响青年用户的信息可见性及内容相关性,使其形成五种不同的感知,分别对青年择偶观产生不同影响。在这一过程中,社交媒体虽然存在信息茧房效应,但只有在一定程度上符合相关条件时才会出现,进而影响青年的择偶观。 展开更多
关键词 社交媒体 青年群体 择偶观 媒介系统依赖理论 信息茧房
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