In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. ...In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. In order to acquire the imperfect channel state information at transmitter (CSIT), a dynamic CSIT model is introduced where the channel temporal and spatial correlations are considered. By utilizing the unchanged channel statistics and accurate outdated feedback channel information jointly, the imperfect CSIT is obtained as the channel estimate and error covariance. Based on the obtained imperfect CSIT, a Minimum Mean-Square Error (MMSE) Tomlinsion-Harashima precoding (THP) is designed and the closed-form solution is derived by the Lagrangian multiplier approach under total power constraint. Simulation results are provided to indicate the preferable performances of the robust THP. Performance analysis with respect to feedback delay and mobile speed is also given.展开更多
E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of ...E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of Enron dataset and the distribution of node degree and strength are analyzed. Then, some rules of e-mail communication network evolution are found. Second, the model of e-mail information propagation is described, and e-mail communication network evolution model based on user information propagation is proposed. Lastly, the simulation proves the correctness of the distribution characteristic of degree and strength of the model proposed and then verifies that the model proposed is closer to the real situation of e-mail communication network through parameter comparison. This research provides the basis for other researches on social network evolution and data communication.展开更多
The relatively high percentage of people with disabilities in Europe combined with the facts of ageing population, strong relation of impairment to age, and as State of the Art shows, dissatisfaction or even unawarene...The relatively high percentage of people with disabilities in Europe combined with the facts of ageing population, strong relation of impairment to age, and as State of the Art shows, dissatisfaction or even unawareness of people with disabilities of available assistive technology are revealing the necessity to incorporate a user-centric approach that beyond 2nd generation practices will achieve to provide embedded and built-in accessibility solutions, as well as toolkits for developers, for ＂engraving＂ accessibility in existing and emerging mass-market ICT-based products, aiming to make accessibility open, plug and play, personalised and configurable, realistic and applicable in various contexts, keeping always the user in the loop. The AEGIS （Accessibility Everywhere： Groundwork, Infrastructure, Standards） IP （Integrated Project） of the 7th European Framework Programme seeks to determine whether 3rd generation access techniques will provide a more accessible, more exploitable and deeply embeddable approach in mainstream ICT （information and communication technologies）. This paper presents the holistic UCD （user-centered design） implementation plan, upon which AEGIS has been based in order to achieve its targets, starting from modelling its target users, in the most efficient way possible.展开更多
基金supported by National Basic Research Program of China (973 Program) (Grant No. 2007CB310604, 2009CB320401)National Natural Science Foundation of China (Grant No. 60772108, 60702048)
文摘In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. In order to acquire the imperfect channel state information at transmitter (CSIT), a dynamic CSIT model is introduced where the channel temporal and spatial correlations are considered. By utilizing the unchanged channel statistics and accurate outdated feedback channel information jointly, the imperfect CSIT is obtained as the channel estimate and error covariance. Based on the obtained imperfect CSIT, a Minimum Mean-Square Error (MMSE) Tomlinsion-Harashima precoding (THP) is designed and the closed-form solution is derived by the Lagrangian multiplier approach under total power constraint. Simulation results are provided to indicate the preferable performances of the robust THP. Performance analysis with respect to feedback delay and mobile speed is also given.
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. QC2015076Funds for the Central Universities of China under grant number HEUCF100602
文摘E-mail communication network evolution model based on user information propagation is studied. First, mathematical representation of weighted e-mail communication network is proposed, and network center parameters of Enron dataset and the distribution of node degree and strength are analyzed. Then, some rules of e-mail communication network evolution are found. Second, the model of e-mail information propagation is described, and e-mail communication network evolution model based on user information propagation is proposed. Lastly, the simulation proves the correctness of the distribution characteristic of degree and strength of the model proposed and then verifies that the model proposed is closer to the real situation of e-mail communication network through parameter comparison. This research provides the basis for other researches on social network evolution and data communication.
文摘The relatively high percentage of people with disabilities in Europe combined with the facts of ageing population, strong relation of impairment to age, and as State of the Art shows, dissatisfaction or even unawareness of people with disabilities of available assistive technology are revealing the necessity to incorporate a user-centric approach that beyond 2nd generation practices will achieve to provide embedded and built-in accessibility solutions, as well as toolkits for developers, for ＂engraving＂ accessibility in existing and emerging mass-market ICT-based products, aiming to make accessibility open, plug and play, personalised and configurable, realistic and applicable in various contexts, keeping always the user in the loop. The AEGIS （Accessibility Everywhere： Groundwork, Infrastructure, Standards） IP （Integrated Project） of the 7th European Framework Programme seeks to determine whether 3rd generation access techniques will provide a more accessible, more exploitable and deeply embeddable approach in mainstream ICT （information and communication technologies）. This paper presents the holistic UCD （user-centered design） implementation plan, upon which AEGIS has been based in order to achieve its targets, starting from modelling its target users, in the most efficient way possible.
