The potential mechanisms of the spreading phenomena uncover the organizations and functions of various systems.However,due to the lack of valid data,most of early works are limited to the simulated process on model ne...The potential mechanisms of the spreading phenomena uncover the organizations and functions of various systems.However,due to the lack of valid data,most of early works are limited to the simulated process on model networks.In this paper,we track and analyze the propagation paths of real spreading events on two social networks:Twitter and Brightkite.The empirical analysis reveals that the spreading probability and the spreading velocity present the explosive growth within a short period,where the spreading probability measures the transferring likelihood between two neighboring nodes,and the spreading velocity is the growth rate of the information in the whole network.Besides,we observe the asynchronism between the spreading probability and the spreading velocity.To explain the interesting and abnormal issue,we introduce the time-varying spreading probability into the susceptible-infected(SI)and linear threshold(LT)models.Both the analytic and experimental results reproduce the spreading phenomenon in real networks,which deepens our understandings of spreading problems.展开更多
Long PN-code acquisition is a difficult and time-consuming task due to long code period.To accelerate acquisition,folding methods like XFAST are widely used.In highdynamic environment however,the application of those ...Long PN-code acquisition is a difficult and time-consuming task due to long code period.To accelerate acquisition,folding methods like XFAST are widely used.In highdynamic environment however,the application of those methods are largely restricted due to nonnegligible residual frequency.This paper proposes a new dual-channel method for fast acquisition of long PN-code.In the proposed method,both non-overlapping local PNcode blocks are employed to correlate with input sample block;the detection process is eased through finding the maximum value among correlation results and verification is made with all the full and partial peaks taken into account.False alarm probabilities from analysis of the verification process are derived.Both theoretical and Monte Carlo simulations reveal that,with respect to acquisition probability and mean acquisition time under the same false alarm rate,dual-channel method has advantage over zero-padding and XFAST based folding methods under certain false alarm probabilities.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61703281,11547040,61803266,61503140,and 61873171)the PhD Start-Up Fund of Natural Science Foundation of Guangdong Province,China(Grant Nos.2017A030310374 and 2016A030313036)+1 种基金the Science and Technology Innovation Commission of Shenzhen,China(Grant No.JCYJ20180305124628810)the China Scholarship Council(Grant No.201806340213).
文摘The potential mechanisms of the spreading phenomena uncover the organizations and functions of various systems.However,due to the lack of valid data,most of early works are limited to the simulated process on model networks.In this paper,we track and analyze the propagation paths of real spreading events on two social networks:Twitter and Brightkite.The empirical analysis reveals that the spreading probability and the spreading velocity present the explosive growth within a short period,where the spreading probability measures the transferring likelihood between two neighboring nodes,and the spreading velocity is the growth rate of the information in the whole network.Besides,we observe the asynchronism between the spreading probability and the spreading velocity.To explain the interesting and abnormal issue,we introduce the time-varying spreading probability into the susceptible-infected(SI)and linear threshold(LT)models.Both the analytic and experimental results reproduce the spreading phenomenon in real networks,which deepens our understandings of spreading problems.
文摘Long PN-code acquisition is a difficult and time-consuming task due to long code period.To accelerate acquisition,folding methods like XFAST are widely used.In highdynamic environment however,the application of those methods are largely restricted due to nonnegligible residual frequency.This paper proposes a new dual-channel method for fast acquisition of long PN-code.In the proposed method,both non-overlapping local PNcode blocks are employed to correlate with input sample block;the detection process is eased through finding the maximum value among correlation results and verification is made with all the full and partial peaks taken into account.False alarm probabilities from analysis of the verification process are derived.Both theoretical and Monte Carlo simulations reveal that,with respect to acquisition probability and mean acquisition time under the same false alarm rate,dual-channel method has advantage over zero-padding and XFAST based folding methods under certain false alarm probabilities.
