Fog computing is an emerging paradigm of cloud computing which to meet the growing computation demand of mobile application. It can help mobile devices to overcome resource constraints by offloading the computationall...Fog computing is an emerging paradigm of cloud computing which to meet the growing computation demand of mobile application. It can help mobile devices to overcome resource constraints by offloading the computationally intensive tasks to cloud servers. The challenge of the cloud is to minimize the time of data transfer and task execution to the user, whose location changes owing to mobility, and the energy consumption for the mobile device. To provide satisfactory computation performance is particularly challenging in the fog computing environment. In this paper, we propose a novel fog computing model and offloading policy which can effectively bring the fog computing power closer to the mobile user. The fog computing model consist of remote cloud nodes and local cloud nodes, which is attached to wireless access infrastructure. And we give task offloading policy taking into account executi+on, energy consumption and other expenses. We finally evaluate the performance of our method through experimental simulations. The experimental results show that this method has a significant effect on reducing the execution time of tasks and energy consumption of mobile devices.展开更多
Coordinated signal processing can obtain a huge transmission gain for Fog Radio Access Networks(F-RANs).However,integrating into large scale,it will lead to high computation complexity in channel estimation and spectr...Coordinated signal processing can obtain a huge transmission gain for Fog Radio Access Networks(F-RANs).However,integrating into large scale,it will lead to high computation complexity in channel estimation and spectral efficiency loss in transmission performance.Thus,a joint cluster formation and channel estimation scheme is proposed in this paper.Considering research remote radio heads(RRHs)centred serving scheme,a coalition game is formulated in order to maximize the spectral efficiency of cooperative RRHs under the conditions of balancing the data rate and the cost of channel estimation.As the cost influences to the necessary consumption of training length and estimation error.Particularly,an iterative semi-blind channel estimation and symbol detection approach is designed by expectation maximization algorithm,where the channel estimation process is initialized by subspace method with lower pilot length.Finally,the simulation results show that a stable cluster formation is established by our proposed coalition game method and it outperforms compared with full coordinated schemes.展开更多
For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(...For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture.展开更多
Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application...Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application for energy storage.Herein,we first used RP to prepare a novel bouquet-like Co_(3)(HPO_(4))_(2)(OH)_(2) by the hydrothermal approach as cathode materials for hybrid supercapacitors(HSC),which delivered a large specific capacity(119.2 mA h g^(−1) at 1 A g^(−1)),a superb rate capability(83.6 mA h g^(−1) at 100 A g^(−1))and a splendid electrochemical stability(92%capacity retention after 5000 cycles at 10 A g^(−1)).Furthermore,a novel HSC device assembled with Co_(3)(HPO_(4))_(2)(OH)_(2) as the cathode,porous carbon(PC)as the anode showed a high energy density of 44.6 W h kg^(−1) and a remarkable power density of 33.75 kW kg^(−1),along with an exceptional cyclic performance(91.8%capacity retention after 10,000 cycles at 3 A g^(−1)).This study not only develops a novel type of high-performance battery-type cathode material,but also provides a new idea for the industrial application of RP.展开更多
The brake-by-wire(BBW)system is an essential part of the intelligent electric vehicle,which is determination of the braking safety and recovery efficiency.To design a safe and efficient booster motor,the design of boo...The brake-by-wire(BBW)system is an essential part of the intelligent electric vehicle,which is determination of the braking safety and recovery efficiency.To design a safe and efficient booster motor,the design of booster motor for BBW system is discussed in this paper.Through comparative analysis,experimental simulation and assessment argument,the scheme of designing a booster motor for brake-by-wire system is completely described.First,the mainstream structure of the BBW system and the main challenges it faces in the assisted motor are discussed.Second,comparing the motors of different types and structures,the motor body and control system scheme suitable for the characteristics of the booster motor system are determined.Then,through the simulation analysis of the ansoft and matlab,the optimization scheme of the motor and performance improvement are proposed.Further,through the actual design of a set of the booster motor system,the safe and efficient motor designing are verified,and the problems involving functional safety are discussed.Finally,focus on the problem while simulation and experiment,some important countermeasures to improve current technology and prospect of in-depth study are pointed out.展开更多
基金supported by the NSFC (61602126)the scientific and technological project of Henan province (162102210214)
文摘Fog computing is an emerging paradigm of cloud computing which to meet the growing computation demand of mobile application. It can help mobile devices to overcome resource constraints by offloading the computationally intensive tasks to cloud servers. The challenge of the cloud is to minimize the time of data transfer and task execution to the user, whose location changes owing to mobility, and the energy consumption for the mobile device. To provide satisfactory computation performance is particularly challenging in the fog computing environment. In this paper, we propose a novel fog computing model and offloading policy which can effectively bring the fog computing power closer to the mobile user. The fog computing model consist of remote cloud nodes and local cloud nodes, which is attached to wireless access infrastructure. And we give task offloading policy taking into account executi+on, energy consumption and other expenses. We finally evaluate the performance of our method through experimental simulations. The experimental results show that this method has a significant effect on reducing the execution time of tasks and energy consumption of mobile devices.
基金supported in part by the State Major Science and Technology Special Project(Grant No.2018ZX03001025)the National Natural Science Foundation of China(No.61831002 and No.61671074)the Fundamental Research Funds for the Central Universities under Grant No.2018XKJC01
文摘Coordinated signal processing can obtain a huge transmission gain for Fog Radio Access Networks(F-RANs).However,integrating into large scale,it will lead to high computation complexity in channel estimation and spectral efficiency loss in transmission performance.Thus,a joint cluster formation and channel estimation scheme is proposed in this paper.Considering research remote radio heads(RRHs)centred serving scheme,a coalition game is formulated in order to maximize the spectral efficiency of cooperative RRHs under the conditions of balancing the data rate and the cost of channel estimation.As the cost influences to the necessary consumption of training length and estimation error.Particularly,an iterative semi-blind channel estimation and symbol detection approach is designed by expectation maximization algorithm,where the channel estimation process is initialized by subspace method with lower pilot length.Finally,the simulation results show that a stable cluster formation is established by our proposed coalition game method and it outperforms compared with full coordinated schemes.
基金financially supported by The Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJB530007,22KJA530001)National Natural Science Foundation of China(22208151)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20220002)the State Key Laboratory of MaterialsOriented Chemical Engineering(SKL-MCE-22B07).
文摘For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture.
基金financially supported by the National Natural Science Foundation of China(21601057)Hunan Provincial Natural Science Foundation(2021JJ30216)。
文摘Red phosphorus(RP)is beneficial to industrialization due to its rich resources,chemical stability and environmental friendliness.However,the low electronic conductivity and large volume expansion limit its application for energy storage.Herein,we first used RP to prepare a novel bouquet-like Co_(3)(HPO_(4))_(2)(OH)_(2) by the hydrothermal approach as cathode materials for hybrid supercapacitors(HSC),which delivered a large specific capacity(119.2 mA h g^(−1) at 1 A g^(−1)),a superb rate capability(83.6 mA h g^(−1) at 100 A g^(−1))and a splendid electrochemical stability(92%capacity retention after 5000 cycles at 10 A g^(−1)).Furthermore,a novel HSC device assembled with Co_(3)(HPO_(4))_(2)(OH)_(2) as the cathode,porous carbon(PC)as the anode showed a high energy density of 44.6 W h kg^(−1) and a remarkable power density of 33.75 kW kg^(−1),along with an exceptional cyclic performance(91.8%capacity retention after 10,000 cycles at 3 A g^(−1)).This study not only develops a novel type of high-performance battery-type cathode material,but also provides a new idea for the industrial application of RP.
基金supported in part by the Excellent Youth Program of Education Department under Project 21B0124in part by the Natural Science Foundation of China under Grant 62003288+1 种基金in part by the Innovation Platform and Talent Program of Hunan Province under Grant 2021RC2095Supported by China Postdoctoral Science Foundation 2022M712673.
文摘The brake-by-wire(BBW)system is an essential part of the intelligent electric vehicle,which is determination of the braking safety and recovery efficiency.To design a safe and efficient booster motor,the design of booster motor for BBW system is discussed in this paper.Through comparative analysis,experimental simulation and assessment argument,the scheme of designing a booster motor for brake-by-wire system is completely described.First,the mainstream structure of the BBW system and the main challenges it faces in the assisted motor are discussed.Second,comparing the motors of different types and structures,the motor body and control system scheme suitable for the characteristics of the booster motor system are determined.Then,through the simulation analysis of the ansoft and matlab,the optimization scheme of the motor and performance improvement are proposed.Further,through the actual design of a set of the booster motor system,the safe and efficient motor designing are verified,and the problems involving functional safety are discussed.Finally,focus on the problem while simulation and experiment,some important countermeasures to improve current technology and prospect of in-depth study are pointed out.
