Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource all...Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource allocation algorithm appropriately.However,few works focus on the interaction that channel’s time-vary characters make the energy transfer inefficiently.To address this,we propose a novel system operation sequence for sensor-cloud system where the Sinks provide SWIPT for sensor nodes opportunistically during downlink phase and collect the data transmitted from sensor nodes in uplink phase.Then,the energy-efficiency maximization problem of the Sinks is presented by considering the time costs and energy consumption of channel detection.It is proved that the formulated problem is an optimal stopping process with optimal stopping rules.An optimal energy-efficiency(OEE)algorithm is designed to obtain the optimal stopping rules for SWIPT.Finally,the simulations are performed based on the OEE algorithm compared with the other two strategies to verify the effectiveness and gains in improving the system efficiency.展开更多
The network architecture has undergone great changes. For example, the network topology of autonomous system level tends to be flattened. In this paper, actual network topology map is constructed through actual networ...The network architecture has undergone great changes. For example, the network topology of autonomous system level tends to be flattened. In this paper, actual network topology map is constructed through actual network routing data, to study and analyze the network structure changes of the Internet recently and the dependence of the Internet on the core AS. In order to achieve the above goals, the experimental analysis framework and some related algorithms were designed. Experimental results show that the Internet architectures gradually become flattening, and the dependence of the Internet on core AS is gradually reduced but the importance of the core ASes is still indispensable. Most traffic between local ASes can be transited through the local infrastructure (such as IXP) rather than the upper ISPs. The observations may guide the design of inter-domain routing protocols and Internet exchange architectures to achieve higher performance and reliability.展开更多
The structural stress/strain induced by K-ion intercalation remains a critical challenge for K-ion batteries.To address this,a dopamine-intercalated WS_(2) hybrid(Dam-WS1.87)with a unique strain-self-relaxation archit...The structural stress/strain induced by K-ion intercalation remains a critical challenge for K-ion batteries.To address this,a dopamine-intercalated WS_(2) hybrid(Dam-WS1.87)with a unique strain-self-relaxation architecture was fabricated.Interestingly,the WS_(2) matrix undergoes a structural transformation owing to the intense infiltration effect of dopamine molecules,expanding interlayer spacing(0.813 nm)and introducing 6.5%S-vacancies while preserving high compaction density(4.0874 gcm^(-3)).The engineered structure demonstrates remarkable mechanical stability,exhibiting only 19.0%crystallite expansion upon full potassiation(vs.101.3%for pristine WS_(2)),demonstrating efficient strain alleviation through its strain-self-relaxation architecture.As a result,Dam-WS1.87delivers reversible capacities of 312.6 m A h g^(-1)/1277.7 mA h cm^(-3)at 0.125 C,along with superior rate capability(maintaining 210.4 m A h g^(-1)at 5 C)and unprecedented cycling stability(85.3%capacity retention after 1400 cycles at 1 C).This work provides new insights into designing strain-tolerant electrode materials for nextgeneration energy storage systems.展开更多
基金This work was supported by Scientific Research Ability Improving Foundation for Young and Middle-Aged University Teachers in Guangxi(No.2020KY04030)The school introduces talents to start scientific research projects(No.2019KJQD17)+1 种基金This work was supported in part by the National Natural Science Foundation of China(No.61762010,No.61862007)Guangxi Natural Science Foundation(No.2018GXNSFAA138147).
文摘Leveraging energy harvesting abilities in wireless network devices has emerged as an effective way to prolong the lifetime of energy constrained systems.The system gains are usually optimized by designing resource allocation algorithm appropriately.However,few works focus on the interaction that channel’s time-vary characters make the energy transfer inefficiently.To address this,we propose a novel system operation sequence for sensor-cloud system where the Sinks provide SWIPT for sensor nodes opportunistically during downlink phase and collect the data transmitted from sensor nodes in uplink phase.Then,the energy-efficiency maximization problem of the Sinks is presented by considering the time costs and energy consumption of channel detection.It is proved that the formulated problem is an optimal stopping process with optimal stopping rules.An optimal energy-efficiency(OEE)algorithm is designed to obtain the optimal stopping rules for SWIPT.Finally,the simulations are performed based on the OEE algorithm compared with the other two strategies to verify the effectiveness and gains in improving the system efficiency.
文摘The network architecture has undergone great changes. For example, the network topology of autonomous system level tends to be flattened. In this paper, actual network topology map is constructed through actual network routing data, to study and analyze the network structure changes of the Internet recently and the dependence of the Internet on the core AS. In order to achieve the above goals, the experimental analysis framework and some related algorithms were designed. Experimental results show that the Internet architectures gradually become flattening, and the dependence of the Internet on core AS is gradually reduced but the importance of the core ASes is still indispensable. Most traffic between local ASes can be transited through the local infrastructure (such as IXP) rather than the upper ISPs. The observations may guide the design of inter-domain routing protocols and Internet exchange architectures to achieve higher performance and reliability.
基金financially supported by the National Natural Science Foundation of China(22578493,22238012,52270115)the Beijing Nova Program(20240484570)+4 种基金the Postdoctoral Fellowship Program of CPSF(2024GZB20240847)the China Postdoctoral Science Foundation(M753609)the CNPC Innovation Found(2024DQ02-0206,2022DQ02-0410)the Science Foundation of China University of Petroleum(Beijing)(2462023QNXZ015,2462024PTJS011)the Open Project Fund of the Ministry of Education Engineering Research Center for Clean Low Carbon Energy(ZX20240167)。
文摘The structural stress/strain induced by K-ion intercalation remains a critical challenge for K-ion batteries.To address this,a dopamine-intercalated WS_(2) hybrid(Dam-WS1.87)with a unique strain-self-relaxation architecture was fabricated.Interestingly,the WS_(2) matrix undergoes a structural transformation owing to the intense infiltration effect of dopamine molecules,expanding interlayer spacing(0.813 nm)and introducing 6.5%S-vacancies while preserving high compaction density(4.0874 gcm^(-3)).The engineered structure demonstrates remarkable mechanical stability,exhibiting only 19.0%crystallite expansion upon full potassiation(vs.101.3%for pristine WS_(2)),demonstrating efficient strain alleviation through its strain-self-relaxation architecture.As a result,Dam-WS1.87delivers reversible capacities of 312.6 m A h g^(-1)/1277.7 mA h cm^(-3)at 0.125 C,along with superior rate capability(maintaining 210.4 m A h g^(-1)at 5 C)and unprecedented cycling stability(85.3%capacity retention after 1400 cycles at 1 C).This work provides new insights into designing strain-tolerant electrode materials for nextgeneration energy storage systems.
