A recommender system is a tool designed to suggest relevant items to users based on their preferences and behaviors.Collaborative filtering,a popular technique within recommender systems,predicts user interests by ana...A recommender system is a tool designed to suggest relevant items to users based on their preferences and behaviors.Collaborative filtering,a popular technique within recommender systems,predicts user interests by analyzing patterns in interactions and similarities between users,leveraging past behavior data to make personalized recommendations.Despite its popularity,collaborative filtering faces notable challenges,and one of them is the issue of grey-sheep users who have unusual tastes in the system.Surprisingly,existing research has not extensively explored outlier detection techniques to address the grey-sheep problem.To fill this research gap,this study conducts a comprehensive comparison of 12 outlier detectionmethods(such as LOF,ABOD,HBOS,etc.)and introduces innovative user representations aimed at improving the identification of outliers within recommender systems.More specifically,we proposed and examined three types of user representations:1)the distribution statistics of user-user similarities,where similarities were calculated based on users’rating vectors;2)the distribution statistics of user-user similarities,but with similarities derived from users represented by latent factors;and 3)latent-factor vector representations.Our experiments on the Movie Lens and Yahoo!Movie datasets demonstrate that user representations based on latent-factor vectors consistently facilitate the identification of more grey-sheep users when applying outlier detection methods.展开更多
Identifying influential users in social networks is of great significance in areas such as public opinion monitoring and commercial promotion.Existing identification methods based on Graph Neural Networks(GNNs)often l...Identifying influential users in social networks is of great significance in areas such as public opinion monitoring and commercial promotion.Existing identification methods based on Graph Neural Networks(GNNs)often lead to yield inaccurate features of influential users due to neighborhood aggregation,and require a large substantial amount of labeled data for training,making them difficult and challenging to apply in practice.To address this issue,we propose a semi-supervised contrastive learning method for identifying influential users.First,the proposed method constructs positive and negative samples for contrastive learning based on multiple node centrality metrics related to influence;then,contrastive learning is employed to guide the encoder to generate various influence-related features for users;finally,with only a small amount of labeled data,an attention-based user classifier is trained to accurately identify influential users.Experiments conducted on three public social network datasets demonstrate that the proposed method,using only 20%of the labeled data as the training set,achieves F1 values that are 5.9%,5.8%,and 8.7%higher than those unsupervised EVC method,and it matches the performance of GNN-based methods such as DeepInf,InfGCN and OlapGN,which require 80%of labeled data as the training set.展开更多
The advent of sixth-generation(6G)networks introduces unprecedented challenges in achieving seamless connectivity,ultra-low latency,and efficient resource management in highly dynamic environments.Although fifth-gener...The advent of sixth-generation(6G)networks introduces unprecedented challenges in achieving seamless connectivity,ultra-low latency,and efficient resource management in highly dynamic environments.Although fifth-generation(5G)networks transformed mobile broadband and machine-type communications at massive scales,their properties of scaling,interference management,and latency remain a limitation in dense high mobility settings.To overcome these limitations,artificial intelligence(AI)and unmanned aerial vehicles(UAVs)have emerged as potential solutions to develop versatile,dynamic,and energy-efficient communication systems.The study proposes an AI-based UAV architecture that utilizes cooperative reinforcement learning(CoRL)to manage an autonomous network.The UAVs collaborate by sharing local observations and real-time state exchanges to optimize user connectivity,movement directions,allocate power,and resource distribution.Unlike conventional centralized or autonomous methods,CoRL involves joint state sharing and conflict-sensitive reward shaping,which ensures fair coverage,less interference,and enhanced adaptability in a dynamic urban environment.Simulations conducted in smart city scenarios with 10 UAVs and 50 ground users demonstrate that the proposed CoRL-based UAV system increases user coverage by up to 10%,achieves convergence 40%faster,and reduces latency and energy consumption by 30%compared with centralized and decentralized baselines.Furthermore,the distributed nature of the algorithm ensures scalability and flexibility,making it well-suited for future large-scale 6G deployments.The results highlighted that AI-enabled UAV systems enhance connectivity,support ultra-reliable low-latency communications(URLLC),and improve 6G network efficiency.Future work will extend the framework with adaptive modulation,beamforming-aware positioning,and real-world testbed deployment.展开更多
Objective： To understand the prevalence and behavioral risk factors of HIV infection among injection drug users in the Pearl River Delta Region （PRDR） of Guangdong province, and to provide evidence for establishing...Objective： To understand the prevalence and behavioral risk factors of HIV infection among injection drug users in the Pearl River Delta Region （PRDR） of Guangdong province, and to provide evidence for establishing effective intervention strategies. Methods： Face to face interviews were conducted and serum samples from injection drug users from detoxification centers and the community were collected for HIV screening. Results： 655 drug users were recruited and interviewed. The HIV seropositive rate was 29.0%. 99.5 % of subjects were injection drug users （IDUs）, of whom,75.4% reported sharing injection equipment. Conclusion： HIV prevalence among injection drug users is high in the PRDR of Guangdong. Injection drug use is the principal behavioral risk factor for HIV transmission. Pragmatic harm reduction programs should be implemented to prevent the spread of HIV infection.展开更多
New idea studying urban parks was opened up by "Reflection on Urban Park:Public Space and Multi-culture". By introducing anthropology into planning and design methodology of urban public space, it provided a...New idea studying urban parks was opened up by "Reflection on Urban Park:Public Space and Multi-culture". By introducing anthropology into planning and design methodology of urban public space, it provided a new research method for the planning of urban park in our country. Through introduction and assessment of the book, existing problems and suggestions of the construction of our urban parks were proposed. In the perspective of urban parks' users, by the method of ethnology and anthropology, cultural diversity of urban public space would be investigated, paying attention to the usage behavior and different cultural characteristics, thinking about how to respect ecology and environmental construction of parks and coordinate the relation between culture and ecology while cultural diversity was respected. What should be considered in the construction of urban parks was not only culture but also ecological environment protection when culture was respected and citizens' interests during environment construction. These were also the fundamental problems needed to be considered and solved in parks' planning, construction and operation.展开更多
The e-mail network is a type of social network. This study analyzes user behavior in e-mail subject participation in organizations by using social network analysis. First, the Enron dataset and the position-related in...The e-mail network is a type of social network. This study analyzes user behavior in e-mail subject participation in organizations by using social network analysis. First, the Enron dataset and the position-related information of an employee are introduced, and methods for deletion of false data are presented. Next, the three-layer model(User, Subject, Keyword) is proposed for analysis of user behavior. Then, the proposed keyword selection algorithm based on a greedy approach, and the influence and propagation of an e-mail subject are defined. Finally, the e-mail user behavior is analyzed for the Enron organization. This study has considerable significance in subject recommendation and character recognition.展开更多
Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell...Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell in cap-and-trade programs. The California’s cap-and-trade program (California’s carbon market hereafter) allows forestland owners from any part of the contiguous United States to supply carbon credits to compliance entities. In this study, we estimate South Carolina (SC) private forestland owners’willingness to accept compensations to participate in the California’s carbon market using a contingent valuation method. Results: We estimate forestland owners’mean willingness to accept as$67 per acre per year. Our results reveal higher probability of participation of forestland owners with interests in preserving forest ecosystems than those who do not. Additionally, forestland owners who trust in information about climate change from scientists or government are willing to participate more than those who do not. Conclusions: Various factors hinder landowners’ability to participate in carbon markets. Forestland owners in SC consider legislative uncertainty and long-time commitment as the main barriers to participation in California’s carbon market. From this research, average forestland tenure in SC is 27 years, which is far less than the 100-year time commitment of the California’s carbon market. Of those who agreed to participate, choosing between adopting and not adopting any of the three main forest management practices in the California’s carbon market:28% are likely to adopt improved forest management (IFM) practices, 24% are likely to adopt reforestation due to understocked forestlands, and 14% are likely to adopt avoided conversion. In another development, the concept of aggregation has dominated discussions in the California’s carbon market of late. It is an advocacy to include small-scale forestlands in the California’s carbon market. To aggregate, different forestland owners will combine their forestlands to participate. We find that 79% of SC forestland owners are willing to aggregate to participate. However, this research is unable to determine how much total forestland is available in SC for carbon market. We recommend future research in the State on forestland owners’participation in carbon market should consider evaluating forestland availability.展开更多
AIM:To characterize the prevalence of hepatitis C virus(HCV)infection among Chinese intravenous drug users(IDUs).METHODS:A total of 432 adult IDUs(95 women and337 men)in Shanghai were included in the study.The third-g...AIM:To characterize the prevalence of hepatitis C virus(HCV)infection among Chinese intravenous drug users(IDUs).METHODS:A total of 432 adult IDUs(95 women and337 men)in Shanghai were included in the study.The third-generation Elecsys Anti-HCV assay(Roche Diagnostics GmbH,Sandhofer Strasse 116,D-68305,Mannheim,Germany)was used to screen for antibodies against HCV.The RIBA strip,a supplemental antiHCV test with high specificity,was performed on all of the samples that tested positive during the initial screening.All of the anti-HCV positive samples were analyzed with a Cobas TaqMan 48 Analyzer(Roche Diagnostics)for direct detection of HCV RNA.All of the HCV RNA-positive samples were sequenced for genotype determination.RESULTS:The preliminary screening identified 262(60.6%)subjects who were seropositive for HCV.Of the 62 females and 200 males seropositive subjects,16(16.7%)and 65(19.3%),respectively,were confirmed by RIBA,yielding an overall HCV seropositive rate of18.8%.Four female(6.5%)and 14 male(7.0%)subjects tested positive for HCV RNA,indicating an active infection rate of 4.2%for the entire study population.The 18 HCV RNA-positive serum samples were genotyped.Seven individuals were genotype 1b,and four were genotype 1a.One individual each was infected with genotypes 2a,2b and 3a.Four subjects were coinfected with multiple strains:two with genotypes 1a and 2a,and two with genotypes 1b and 2a.The active infection rate among HCV-seropositive individuals was22.2%,which was significantly lower than most estimates.CONCLUSION:The prevalence of HCV is relatively low among IDUs in Shanghai,with a spontaneous recovery rate much higher than previous estimates.展开更多
Hong Kong is a hyper-dense city with 7x10(6) people living in an area of 1100km(2). One way to improve the livability of compacted and congested cities like Hong Kong is through the provision of urban parks, an aspect...Hong Kong is a hyper-dense city with 7x10(6) people living in an area of 1100km(2). One way to improve the livability of compacted and congested cities like Hong Kong is through the provision of urban parks, an aspect that has largely been under-researched. This study focuses on how users perceive and utilize various facilities in the Kowloon Park. The findings revealed that the Kowloon Park is one of the most preferred parks in Hong Kong for both local residents and tourists. Users were quite satisfied with the park's facilities. Notably, the most important component of an urban park is its greenery. This is followed by water elements, seating places, and facilities for various recreational activities. The improvements users would like to see in urban parks include good design and management, meeting users' needs, overcoming barriers to use, and providing a high quality and varied experience for different groups in the community. The findings of this study provide a good basis to address park management issues from the users' perspective. In particular, parks should provide easy access, encourage optimum usage and enable complimentary improvements to the environment.展开更多
Tree shrews(Tupaia spp.)have been used in neuroscience research since the 1960s due to their evolutionary proximity to primates.The use of and interest in this animal model have recently increased,in part due to the a...Tree shrews(Tupaia spp.)have been used in neuroscience research since the 1960s due to their evolutionary proximity to primates.The use of and interest in this animal model have recently increased,in part due to the adaptation of modern neuroscience tools in this species.These tools include quantitative behavioral assays,calcium imaging,optogenetics and transgenics.To facilitate the exchange and development of these new technologies and associated research findings,we organized the inaugural“Tree Shrew Users Meeting”which was held online due to the COVID-19 pandemic.Here,we review this meeting and discuss the history of tree shrews as an animal model in neuroscience research and summarize the current themes being investigated using this animal,as well as future directions.展开更多
According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respecti...According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users＇ unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user＇s traffic load, the more rapidly the SU2＇s cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI＇s arrival rate, the more obviously both SUI＇s and SU2＇s handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users.展开更多
This paper explores the uses’ influences on microblog. At first, according to the social network theory, we present an analysis of information transmitting network structure based on the relationship of following and...This paper explores the uses’ influences on microblog. At first, according to the social network theory, we present an analysis of information transmitting network structure based on the relationship of following and followed phenomenon of microblog users. Informed by the microblog user behavior analysis, the paper also addresses a model for calculating weights of users’ influence. It proposes a U-R model, using which we can evaluate users’ influence based on PageRank algorithms and analyzes user behaviors. In the U-R model, the effect of user behaviors is explored and PageRank is applied to evaluate the importance and the influence of every user in a microblog network by repeatedly iterating their own U-R value. The users’ influences in a microblog network can be ranked by the U-R value. Finally, the validity of U-R model is proved with a real-life numerical example.展开更多
Due to the increase in the number of smart meter devices,a power grid generates a large amount of data.Analyzing the data can help in understanding the users’electricity consumption behavior and demands;thus,enabling...Due to the increase in the number of smart meter devices,a power grid generates a large amount of data.Analyzing the data can help in understanding the users’electricity consumption behavior and demands;thus,enabling better service to be provided to them.Performing power load profile clustering is the basis for mining the users’electricity consumption behavior.By examining the complexity,randomness,and uncertainty of the users’electricity consumption behavior,this paper proposes an ensemble clustering method to analyze this behavior.First,principle component analysis(PCA)is used to reduce the dimensions of the data.Subsequently,the single clustering method is used,and the majority is selected for integrated clustering.As a result,the users’electricity consumption behavior is classified into different modes,and their characteristics are analyzed in detail.This paper examines the electricity power data of 19 real users in China for simulation purposes.This manuscript provides a thorough analysis along with suggestions for the users’weekly electricity consumption behavior.The results verify the effectiveness of the proposed method.展开更多
To investigate the features of various hepatitis virus infection in intravenous drug users （IVDU）, we conducted an epidemiological survey of hepatitis viruses including hepatitis B virus （HBV）, hepatitis C virus ...To investigate the features of various hepatitis virus infection in intravenous drug users （IVDU）, we conducted an epidemiological survey of hepatitis viruses including hepatitis B virus （HBV）, hepatitis C virus （HCV）, hepatitis D virus （HDV） and hepatitis G virus （HGV） in IVDU. The correlation of Tn lymphocyte cytokine and hepatitis virus infection was examined. A. study population of 406 IVDU consisted of 383 males and 23 females. HBV-DNA and HCV-RNA were detected by fluorescence quantitative polymerase chain reaction. HBsAg, HBeAg, anti-HBc, anti-HCV, HDV-Ag and anti-HGV were assayed by ELISA. The levels of cytokines of TH1 and TH2 were measured by ELISA. The similar indices taken from 102 healthy persons served as controls. The infection rate of each virus among IVDU was 36.45% for HBV, 69. 7 % for HCV, 2.22 % for HDV, and 1.97 % for HGV, respectively. The co-infection rate of HBV and HCV was detected in 113 of 406 （27. 83 %）. In contrast, among controls, the infection rate was 17.65% for HBV and 0% for the other hepatitis viruses. The levels of PHA-induced cytokines （IFN-γ and IL-4） and the level of serum IL-2 were obviously decreased in IVDU. On the other hand, the level of serum IL-4 was increased. The IFN-γ level was continuously decreased when the IVDU was infected with HBV/HCV. In conclusion, HBV and HCV infection were common in this population of IVDU and they had led to a high incidence of impaired TH 1 cytokine levels.展开更多
Forest vegetation management has evolved as a recognized component of intensive forest management practice. It involves the management of competing vegetation necessary to obtain the high yields expected in modern for...Forest vegetation management has evolved as a recognized component of intensive forest management practice. It involves the management of competing vegetation necessary to obtain the high yields expected in modern forest plantations via control of interfering plants that influence regeneration outcome, impact timber stand development, and limit native plant and wildlife diversity. It includes cultural control, fire control, mechanical control, biological control, and chemical control. The public perception of forest vegetation management, especially chemical control, is sometimes negative due to health and environmental concerns. It is an important tool in the forest management alternatives available to consulting foresters managing family forest lands (the vast majority of private forest land in the United States). We report on a study that addresses the motivations of family forest owners that implement forest vegetation management practices and the motivation of those who chose not to implement after forester recommendations to do so. For those who do implement forest vegetation management, improvement of wildlife habitat and increased timber growth was the main motivation. For those who did not, cost was the main concern. Size of forest holding plays a major role in determining who will practice intensive forestry.展开更多
The default mode network is associated with senior cognitive functions in humans. In this study, we performed independent component analysis of blood oxygenation signals from 14 heroin users and 13 matched normal cont...The default mode network is associated with senior cognitive functions in humans. In this study, we performed independent component analysis of blood oxygenation signals from 14 heroin users and 13 matched normal controls in the resting state through functional MRI scans. Results showed that the default mode network was significantly activated in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users, and an enhanced activation signal was observed in the right inferior parietal Iobule （P 〈 0.05, corrected for false discovery rate）. Experimental findings indicate that the default mode network is altered in heroin users.展开更多
For the super user privilege control problem in system services, a user permission isolation method is proposed. Based on virtualization technology, the permission limited environments are constructed for different us...For the super user privilege control problem in system services, a user permission isolation method is proposed. Based on virtualization technology, the permission limited environments are constructed for different users. According to privilege sets, the users, mapping relations are built among users, isolated domains and program modules. Besides, we give an algorithm for division of program permissions based on Concept Lattices. And the security strategies are designed for different isolated domains. Finally, we propose the implications of least privilege, and prove that the method eliminates the potential privileged users in system services.展开更多
文摘A recommender system is a tool designed to suggest relevant items to users based on their preferences and behaviors.Collaborative filtering,a popular technique within recommender systems,predicts user interests by analyzing patterns in interactions and similarities between users,leveraging past behavior data to make personalized recommendations.Despite its popularity,collaborative filtering faces notable challenges,and one of them is the issue of grey-sheep users who have unusual tastes in the system.Surprisingly,existing research has not extensively explored outlier detection techniques to address the grey-sheep problem.To fill this research gap,this study conducts a comprehensive comparison of 12 outlier detectionmethods(such as LOF,ABOD,HBOS,etc.)and introduces innovative user representations aimed at improving the identification of outliers within recommender systems.More specifically,we proposed and examined three types of user representations:1)the distribution statistics of user-user similarities,where similarities were calculated based on users’rating vectors;2)the distribution statistics of user-user similarities,but with similarities derived from users represented by latent factors;and 3)latent-factor vector representations.Our experiments on the Movie Lens and Yahoo!Movie datasets demonstrate that user representations based on latent-factor vectors consistently facilitate the identification of more grey-sheep users when applying outlier detection methods.
基金supported by the National Key Project of the National Natural Science Foundation of China under Grant No.U23A20305.
文摘Identifying influential users in social networks is of great significance in areas such as public opinion monitoring and commercial promotion.Existing identification methods based on Graph Neural Networks(GNNs)often lead to yield inaccurate features of influential users due to neighborhood aggregation,and require a large substantial amount of labeled data for training,making them difficult and challenging to apply in practice.To address this issue,we propose a semi-supervised contrastive learning method for identifying influential users.First,the proposed method constructs positive and negative samples for contrastive learning based on multiple node centrality metrics related to influence;then,contrastive learning is employed to guide the encoder to generate various influence-related features for users;finally,with only a small amount of labeled data,an attention-based user classifier is trained to accurately identify influential users.Experiments conducted on three public social network datasets demonstrate that the proposed method,using only 20%of the labeled data as the training set,achieves F1 values that are 5.9%,5.8%,and 8.7%higher than those unsupervised EVC method,and it matches the performance of GNN-based methods such as DeepInf,InfGCN and OlapGN,which require 80%of labeled data as the training set.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2025-00559546)supported by the IITP(Institute of Information&Coummunications Technology Planning&Evaluation)-ITRC(Information Technology Research Center)grant funded by the Korea government(Ministry of Science and ICT)(IITP-2025-RS-2023-00259004).
文摘The advent of sixth-generation(6G)networks introduces unprecedented challenges in achieving seamless connectivity,ultra-low latency,and efficient resource management in highly dynamic environments.Although fifth-generation(5G)networks transformed mobile broadband and machine-type communications at massive scales,their properties of scaling,interference management,and latency remain a limitation in dense high mobility settings.To overcome these limitations,artificial intelligence(AI)and unmanned aerial vehicles(UAVs)have emerged as potential solutions to develop versatile,dynamic,and energy-efficient communication systems.The study proposes an AI-based UAV architecture that utilizes cooperative reinforcement learning(CoRL)to manage an autonomous network.The UAVs collaborate by sharing local observations and real-time state exchanges to optimize user connectivity,movement directions,allocate power,and resource distribution.Unlike conventional centralized or autonomous methods,CoRL involves joint state sharing and conflict-sensitive reward shaping,which ensures fair coverage,less interference,and enhanced adaptability in a dynamic urban environment.Simulations conducted in smart city scenarios with 10 UAVs and 50 ground users demonstrate that the proposed CoRL-based UAV system increases user coverage by up to 10%,achieves convergence 40%faster,and reduces latency and energy consumption by 30%compared with centralized and decentralized baselines.Furthermore,the distributed nature of the algorithm ensures scalability and flexibility,making it well-suited for future large-scale 6G deployments.The results highlighted that AI-enabled UAV systems enhance connectivity,support ultra-reliable low-latency communications(URLLC),and improve 6G network efficiency.Future work will extend the framework with adaptive modulation,beamforming-aware positioning,and real-world testbed deployment.
文摘Objective： To understand the prevalence and behavioral risk factors of HIV infection among injection drug users in the Pearl River Delta Region （PRDR） of Guangdong province, and to provide evidence for establishing effective intervention strategies. Methods： Face to face interviews were conducted and serum samples from injection drug users from detoxification centers and the community were collected for HIV screening. Results： 655 drug users were recruited and interviewed. The HIV seropositive rate was 29.0%. 99.5 % of subjects were injection drug users （IDUs）, of whom,75.4% reported sharing injection equipment. Conclusion： HIV prevalence among injection drug users is high in the PRDR of Guangdong. Injection drug use is the principal behavioral risk factor for HIV transmission. Pragmatic harm reduction programs should be implemented to prevent the spread of HIV infection.
文摘New idea studying urban parks was opened up by "Reflection on Urban Park:Public Space and Multi-culture". By introducing anthropology into planning and design methodology of urban public space, it provided a new research method for the planning of urban park in our country. Through introduction and assessment of the book, existing problems and suggestions of the construction of our urban parks were proposed. In the perspective of urban parks' users, by the method of ethnology and anthropology, cultural diversity of urban public space would be investigated, paying attention to the usage behavior and different cultural characteristics, thinking about how to respect ecology and environmental construction of parks and coordinate the relation between culture and ecology while cultural diversity was respected. What should be considered in the construction of urban parks was not only culture but also ecological environment protection when culture was respected and citizens' interests during environment construction. These were also the fundamental problems needed to be considered and solved in parks' planning, construction and operation.
基金sponsored by the National Natural Science Foundation of China under grant number No.61100008,61201084the China Postdoctoral Science Foundation under Grant No.2013M541346+3 种基金Heilongiiang Postdoctoral Special Fund(Postdoctoral Youth Talent Program)under Grant No.LBH-TZ0504Heilongjiang Postdoctoral Fund under Grant No.LBH-Z13058the Natural Science Foundation of Heilongjiang Province of China under Grant No.QC2015076The Fundamental Research Funds for the Central Universities of China under grant number HEUCF100602
文摘The e-mail network is a type of social network. This study analyzes user behavior in e-mail subject participation in organizations by using social network analysis. First, the Enron dataset and the position-related information of an employee are introduced, and methods for deletion of false data are presented. Next, the three-layer model(User, Subject, Keyword) is proposed for analysis of user behavior. Then, the proposed keyword selection algorithm based on a greedy approach, and the influence and propagation of an e-mail subject are defined. Finally, the e-mail user behavior is analyzed for the Enron organization. This study has considerable significance in subject recommendation and character recognition.
基金funded by the South Carolina Natural Resources Conservation Service(SC NRCS)with grant number 2021917
文摘Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell in cap-and-trade programs. The California’s cap-and-trade program (California’s carbon market hereafter) allows forestland owners from any part of the contiguous United States to supply carbon credits to compliance entities. In this study, we estimate South Carolina (SC) private forestland owners’willingness to accept compensations to participate in the California’s carbon market using a contingent valuation method. Results: We estimate forestland owners’mean willingness to accept as$67 per acre per year. Our results reveal higher probability of participation of forestland owners with interests in preserving forest ecosystems than those who do not. Additionally, forestland owners who trust in information about climate change from scientists or government are willing to participate more than those who do not. Conclusions: Various factors hinder landowners’ability to participate in carbon markets. Forestland owners in SC consider legislative uncertainty and long-time commitment as the main barriers to participation in California’s carbon market. From this research, average forestland tenure in SC is 27 years, which is far less than the 100-year time commitment of the California’s carbon market. Of those who agreed to participate, choosing between adopting and not adopting any of the three main forest management practices in the California’s carbon market:28% are likely to adopt improved forest management (IFM) practices, 24% are likely to adopt reforestation due to understocked forestlands, and 14% are likely to adopt avoided conversion. In another development, the concept of aggregation has dominated discussions in the California’s carbon market of late. It is an advocacy to include small-scale forestlands in the California’s carbon market. To aggregate, different forestland owners will combine their forestlands to participate. We find that 79% of SC forestland owners are willing to aggregate to participate. However, this research is unable to determine how much total forestland is available in SC for carbon market. We recommend future research in the State on forestland owners’participation in carbon market should consider evaluating forestland availability.
基金Supported by Science and Technology Commission Xuhui District and Xuhui Health Bureau of ShanghaiNo.SHXH201226
文摘AIM:To characterize the prevalence of hepatitis C virus(HCV)infection among Chinese intravenous drug users(IDUs).METHODS:A total of 432 adult IDUs(95 women and337 men)in Shanghai were included in the study.The third-generation Elecsys Anti-HCV assay(Roche Diagnostics GmbH,Sandhofer Strasse 116,D-68305,Mannheim,Germany)was used to screen for antibodies against HCV.The RIBA strip,a supplemental antiHCV test with high specificity,was performed on all of the samples that tested positive during the initial screening.All of the anti-HCV positive samples were analyzed with a Cobas TaqMan 48 Analyzer(Roche Diagnostics)for direct detection of HCV RNA.All of the HCV RNA-positive samples were sequenced for genotype determination.RESULTS:The preliminary screening identified 262(60.6%)subjects who were seropositive for HCV.Of the 62 females and 200 males seropositive subjects,16(16.7%)and 65(19.3%),respectively,were confirmed by RIBA,yielding an overall HCV seropositive rate of18.8%.Four female(6.5%)and 14 male(7.0%)subjects tested positive for HCV RNA,indicating an active infection rate of 4.2%for the entire study population.The 18 HCV RNA-positive serum samples were genotyped.Seven individuals were genotype 1b,and four were genotype 1a.One individual each was infected with genotypes 2a,2b and 3a.Four subjects were coinfected with multiple strains:two with genotypes 1a and 2a,and two with genotypes 1b and 2a.The active infection rate among HCV-seropositive individuals was22.2%,which was significantly lower than most estimates.CONCLUSION:The prevalence of HCV is relatively low among IDUs in Shanghai,with a spontaneous recovery rate much higher than previous estimates.
基金Under the auspices of the Germany-Hong Kong Joint Research Scheme (No.GER/99-00/01) and the Faculty Re-search Grant of the Hong Kong Baptist University (No.FRG/00-01/I-38)
文摘Hong Kong is a hyper-dense city with 7x10(6) people living in an area of 1100km(2). One way to improve the livability of compacted and congested cities like Hong Kong is through the provision of urban parks, an aspect that has largely been under-researched. This study focuses on how users perceive and utilize various facilities in the Kowloon Park. The findings revealed that the Kowloon Park is one of the most preferred parks in Hong Kong for both local residents and tourists. Users were quite satisfied with the park's facilities. Notably, the most important component of an urban park is its greenery. This is followed by water elements, seating places, and facilities for various recreational activities. The improvements users would like to see in urban parks include good design and management, meeting users' needs, overcoming barriers to use, and providing a high quality and varied experience for different groups in the community. The findings of this study provide a good basis to address park management issues from the users' perspective. In particular, parks should provide easy access, encourage optimum usage and enable complimentary improvements to the environment.
基金supported by the National Institutes of Health Grant EY032327 (to D.F.)
文摘Tree shrews(Tupaia spp.)have been used in neuroscience research since the 1960s due to their evolutionary proximity to primates.The use of and interest in this animal model have recently increased,in part due to the adaptation of modern neuroscience tools in this species.These tools include quantitative behavioral assays,calcium imaging,optogenetics and transgenics.To facilitate the exchange and development of these new technologies and associated research findings,we organized the inaugural“Tree Shrew Users Meeting”which was held online due to the COVID-19 pandemic.Here,we review this meeting and discuss the history of tree shrews as an animal model in neuroscience research and summarize the current themes being investigated using this animal,as well as future directions.
基金The National Natural Science Foundation of China(No.60972026,61271207)the National Science and Technology Major Project(No.2010ZX03006-002-01)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education(No.20090092110009)the Specialized Development Foundation for the Achievement Transformation of Jiangsu Province(No.BA2010023)
文摘According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users＇ unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user＇s traffic load, the more rapidly the SU2＇s cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI＇s arrival rate, the more obviously both SUI＇s and SU2＇s handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users.
文摘This paper explores the uses’ influences on microblog. At first, according to the social network theory, we present an analysis of information transmitting network structure based on the relationship of following and followed phenomenon of microblog users. Informed by the microblog user behavior analysis, the paper also addresses a model for calculating weights of users’ influence. It proposes a U-R model, using which we can evaluate users’ influence based on PageRank algorithms and analyzes user behaviors. In the U-R model, the effect of user behaviors is explored and PageRank is applied to evaluate the importance and the influence of every user in a microblog network by repeatedly iterating their own U-R value. The users’ influences in a microblog network can be ranked by the U-R value. Finally, the validity of U-R model is proved with a real-life numerical example.
基金supported by the State Grid Science and Technology Project (No.5442AI90009)Natural Science Foundation of China (No. 6170337)
文摘Due to the increase in the number of smart meter devices,a power grid generates a large amount of data.Analyzing the data can help in understanding the users’electricity consumption behavior and demands;thus,enabling better service to be provided to them.Performing power load profile clustering is the basis for mining the users’electricity consumption behavior.By examining the complexity,randomness,and uncertainty of the users’electricity consumption behavior,this paper proposes an ensemble clustering method to analyze this behavior.First,principle component analysis(PCA)is used to reduce the dimensions of the data.Subsequently,the single clustering method is used,and the majority is selected for integrated clustering.As a result,the users’electricity consumption behavior is classified into different modes,and their characteristics are analyzed in detail.This paper examines the electricity power data of 19 real users in China for simulation purposes.This manuscript provides a thorough analysis along with suggestions for the users’weekly electricity consumption behavior.The results verify the effectiveness of the proposed method.
基金This project was supported by a grant from the NationalNatural Science Foundation of China (No .30160083)
文摘To investigate the features of various hepatitis virus infection in intravenous drug users （IVDU）, we conducted an epidemiological survey of hepatitis viruses including hepatitis B virus （HBV）, hepatitis C virus （HCV）, hepatitis D virus （HDV） and hepatitis G virus （HGV） in IVDU. The correlation of Tn lymphocyte cytokine and hepatitis virus infection was examined. A. study population of 406 IVDU consisted of 383 males and 23 females. HBV-DNA and HCV-RNA were detected by fluorescence quantitative polymerase chain reaction. HBsAg, HBeAg, anti-HBc, anti-HCV, HDV-Ag and anti-HGV were assayed by ELISA. The levels of cytokines of TH1 and TH2 were measured by ELISA. The similar indices taken from 102 healthy persons served as controls. The infection rate of each virus among IVDU was 36.45% for HBV, 69. 7 % for HCV, 2.22 % for HDV, and 1.97 % for HGV, respectively. The co-infection rate of HBV and HCV was detected in 113 of 406 （27. 83 %）. In contrast, among controls, the infection rate was 17.65% for HBV and 0% for the other hepatitis viruses. The levels of PHA-induced cytokines （IFN-γ and IL-4） and the level of serum IL-2 were obviously decreased in IVDU. On the other hand, the level of serum IL-4 was increased. The IFN-γ level was continuously decreased when the IVDU was infected with HBV/HCV. In conclusion, HBV and HCV infection were common in this population of IVDU and they had led to a high incidence of impaired TH 1 cytokine levels.
文摘Forest vegetation management has evolved as a recognized component of intensive forest management practice. It involves the management of competing vegetation necessary to obtain the high yields expected in modern forest plantations via control of interfering plants that influence regeneration outcome, impact timber stand development, and limit native plant and wildlife diversity. It includes cultural control, fire control, mechanical control, biological control, and chemical control. The public perception of forest vegetation management, especially chemical control, is sometimes negative due to health and environmental concerns. It is an important tool in the forest management alternatives available to consulting foresters managing family forest lands (the vast majority of private forest land in the United States). We report on a study that addresses the motivations of family forest owners that implement forest vegetation management practices and the motivation of those who chose not to implement after forester recommendations to do so. For those who do implement forest vegetation management, improvement of wildlife habitat and increased timber growth was the main motivation. For those who did not, cost was the main concern. Size of forest holding plays a major role in determining who will practice intensive forestry.
基金sponsored by a grant from the National Natural Science Foundation of China,No.30973084-C160801,C010604the Natural Science Foundation of Anhui Province,No.11040606M167
文摘The default mode network is associated with senior cognitive functions in humans. In this study, we performed independent component analysis of blood oxygenation signals from 14 heroin users and 13 matched normal controls in the resting state through functional MRI scans. Results showed that the default mode network was significantly activated in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users, and an enhanced activation signal was observed in the right inferior parietal Iobule （P 〈 0.05, corrected for false discovery rate）. Experimental findings indicate that the default mode network is altered in heroin users.
文摘For the super user privilege control problem in system services, a user permission isolation method is proposed. Based on virtualization technology, the permission limited environments are constructed for different users. According to privilege sets, the users, mapping relations are built among users, isolated domains and program modules. Besides, we give an algorithm for division of program permissions based on Concept Lattices. And the security strategies are designed for different isolated domains. Finally, we propose the implications of least privilege, and prove that the method eliminates the potential privileged users in system services.
