In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards...In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.展开更多
This paper studies the web third-person effect （WTPE） hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics （i.e., shares and likes of news a...This paper studies the web third-person effect （WTPE） hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics （i.e., shares and likes of news articles） in shaping users＇ opinion about the websites. Users＇ news sharing intention in social media is also investigated. Based on a structured online questionnaire （N = 7,404）, the results confirm that WTPE can be found in social media metrics without the presence of specific message content. It should be noted that the effect was found at three perceptual levels, self, friends, and other users. Regarding intention for news sharing, text was indicated as the most important reason among Internet users. Finally, the work demonstrates significant correlations between WTPE and article characteristics that influence people＇s attitudes to share news online.展开更多
基金supported in part by the National Basic Research Program of China(973 Program)under Grant 2013CB336600the Beijing Natural Science Foundation under Grant 4131003+1 种基金the National Natural Science Foundation of China under Grant{61201187,61422109}the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions under Grant YETP0110
文摘In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.
文摘This paper studies the web third-person effect （WTPE） hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics （i.e., shares and likes of news articles） in shaping users＇ opinion about the websites. Users＇ news sharing intention in social media is also investigated. Based on a structured online questionnaire （N = 7,404）, the results confirm that WTPE can be found in social media metrics without the presence of specific message content. It should be noted that the effect was found at three perceptual levels, self, friends, and other users. Regarding intention for news sharing, text was indicated as the most important reason among Internet users. Finally, the work demonstrates significant correlations between WTPE and article characteristics that influence people＇s attitudes to share news online.
