This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly...This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly,a multiple access network selection mathematical model based on information theory is presented.From the perspective of information theory,access selection is essentially a process to reduce the information entropy in the system.It can be found that the lower the information entropy is,the better the system performance fulfills.Therefore,this model is designed to reduce the information entropy by removing redundant parameters,and to avoid the computational cost as well.Secondly,for model implementation,the Principal Component Analysis(PCA) is employed to process the observation data to find out the related factors which affect the users most.As a result,the information entropy is decreased.Theoretical analysis proves that system loss and computational complexity have been decreased by using the proposed approach,while the network QoS and accuracy are guaranteed.Finally,simulation results show that our scheme achieves much better system performance in terms of packet delay,throughput and call blocking probability than other currently existing ones.展开更多
Background: The United Arab Emirates aims to provide “world-class healthcare” to its citizens. This study aims to determine the association between overall satisfaction and various aspects of healthcare services in ...Background: The United Arab Emirates aims to provide “world-class healthcare” to its citizens. This study aims to determine the association between overall satisfaction and various aspects of healthcare services in the United Arab Emirates on a country level. Methods: The data was collected from 5855 respondents on the affordability, quality, accessibility, and responsiveness dimensions of health care. Besides frequency tables and descriptive statistics, statistical methods, such as Principal Component Analysis and Multiple Regression, were used to reduce and model the association between dependent (overall satisfaction) and independent (affordability, quality, accessibility, and responsiveness) variables. Results: The preliminary analysis using frequency tables and descriptive clearly highlighted the uncertainty associated with affordability and responsiveness dimensions of healthcare provision in the country. Analysis of variance and t-test results indicated statistically significant differences between perceptions of the respondents based on the socio-demographic factors and other factors such as the kind of insurance held by respondents, having a designated family physician, recent medical visits in the UAE, and intention to go back to home countries for medical treatment. The findings indicated higher satisfaction levels with quality and accessibility and lower satisfaction levels with affordability and responsiveness. Recommendations are provided to address the latter two factors. Conclusion: The study identifies healthcare service provision issues in the United Arab Emirates and recommends enhancing affordability and responsiveness.展开更多
Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractic...Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.展开更多
基金supported by National Natural Science Foundation of China under Grant No.60971083National International Science and Technology Cooperation Project of China (No.2010DFA11320)
文摘This paper brings forward a novel dynamic multiple access network selection scheme(NDMAS),which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters.Firstly,a multiple access network selection mathematical model based on information theory is presented.From the perspective of information theory,access selection is essentially a process to reduce the information entropy in the system.It can be found that the lower the information entropy is,the better the system performance fulfills.Therefore,this model is designed to reduce the information entropy by removing redundant parameters,and to avoid the computational cost as well.Secondly,for model implementation,the Principal Component Analysis(PCA) is employed to process the observation data to find out the related factors which affect the users most.As a result,the information entropy is decreased.Theoretical analysis proves that system loss and computational complexity have been decreased by using the proposed approach,while the network QoS and accuracy are guaranteed.Finally,simulation results show that our scheme achieves much better system performance in terms of packet delay,throughput and call blocking probability than other currently existing ones.
文摘Background: The United Arab Emirates aims to provide “world-class healthcare” to its citizens. This study aims to determine the association between overall satisfaction and various aspects of healthcare services in the United Arab Emirates on a country level. Methods: The data was collected from 5855 respondents on the affordability, quality, accessibility, and responsiveness dimensions of health care. Besides frequency tables and descriptive statistics, statistical methods, such as Principal Component Analysis and Multiple Regression, were used to reduce and model the association between dependent (overall satisfaction) and independent (affordability, quality, accessibility, and responsiveness) variables. Results: The preliminary analysis using frequency tables and descriptive clearly highlighted the uncertainty associated with affordability and responsiveness dimensions of healthcare provision in the country. Analysis of variance and t-test results indicated statistically significant differences between perceptions of the respondents based on the socio-demographic factors and other factors such as the kind of insurance held by respondents, having a designated family physician, recent medical visits in the UAE, and intention to go back to home countries for medical treatment. The findings indicated higher satisfaction levels with quality and accessibility and lower satisfaction levels with affordability and responsiveness. Recommendations are provided to address the latter two factors. Conclusion: The study identifies healthcare service provision issues in the United Arab Emirates and recommends enhancing affordability and responsiveness.
基金Supported by the National Natural Science Foundation of China(No.90818004and61100054)Program for New Century Excellent Talents in University(No.NCET-10-0140)+1 种基金Excellent Youth Foundation of Hunan Scientific Committee(No.11JJ1011)Scientific Research Fundof Hunan Educational Committee(No.09K085and11B048)
文摘Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user's preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user's QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.
