In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-B...In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-Based Location-Aided Routing(DBLAR) for MANET has been proposed.By tracing the location information of destination nodes and referring to distance change between nodes to adjust route discovery dynamically,the proposed routing algorithm can avoid flooding in the whole networks.Besides,Distance Update Threshold(DUT) is set up to reach the balance between real-time ability and update overhead of location information of nodes,meanwhile,the detection of relative distance vector can achieve the goal of adjusting forwarding condition.Simulation results reveal that DBLAR performs better than LAR1 in terms of packet successful delivery ratio,average end-to-end delay and routing-load,and the set of DUT and relative distance vector has a significant impact on this algorithm.展开更多
We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists betw...We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists between both alternative gravity formulas with respect to the distances between mass centers. We conclude a one-to-one mapping of the two gravitational formulas. We don’t need Einstein’s construct of spacetime bending by matter.展开更多
Cooperative localization(CL)utilizing multiple unmanned aerial vehides(UAVs)has become the current development trend and research hotspot.The tnditional distance-based CL method.typically uses principle of the spheric...Cooperative localization(CL)utilizing multiple unmanned aerial vehides(UAVs)has become the current development trend and research hotspot.The tnditional distance-based CL method.typically uses principle of the spherical intersection to achieve UAV high-precision positioning.However,this distance based CL strategy requires several leader UAVs at the known positions.Thus,a cooperative localization method for leader-follower multiple UA Vs using continuous relative ranging information is proposed in this paper.Aiming at the UAV formation consists of a leader UAV node with the known position and at least a follower UAV that needs to be located.Using the Inertial short-time high-precision relative position constraint and the con-tinuous relative distance constraints with the leader UAV nodes,the closed-form solution of follower UAV's three-dimensional position can be obtained using spherical intersection prin-ciple.On this basis,we derive and construct follower UAV's position observation equation.The:developed strategy requires a single known position leader UAV node to realize high-precision CL,which can efctively solve the taditional distance-based collaborative location problem in case the number of leader UAVs is small.The simulation and experimental results demonstrate that the proposed method significantly improves follower UAV's positioning accuracy,and neglects the limitation of the traditional distance-based CL method on the number of leader UAV nodes at known positions.展开更多
Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational ...Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.展开更多
The cosmic distance duality relation(DDR)is constrained by a combination of type-Ⅰa supernovae(SNe la)and strong gravitational lensing(SGL)systems using the deep learning method.To make use of the full SGL data,we re...The cosmic distance duality relation(DDR)is constrained by a combination of type-Ⅰa supernovae(SNe la)and strong gravitational lensing(SGL)systems using the deep learning method.To make use of the full SGL data,we reconstruct the luminosity distance from SNeⅠa up to the highest redshift of SGL using deep learning,and then,this luminosity distance is compared with the angular diameter distance obtained from SGL.Considering the influence of the lens mass profile,we constrain the possible violation of the DDR in three lens mass models.The results show that.in the singular isothermal sphere and extended power-law models,the DDR is violated at a high confidence level,with the violation parameterη0=-0.193-0.019+0.021andη0=-0.247-0.013+0.014,respectively.In the power-law model,however,the DDR is verified within a 1σconfidence level,with the violation parameterη0=-0.014-0.045+0.053.Our results demonstrate that the constraints on the DDR strongly depend on the lens mass models.Given a specific lens mass model,the DDR can be constrained at a precision of O(10-2)using deep learning.展开更多
The Tethered Space Net Robot(TSNR)is an innovative solution for active space debris capture and removal.Its large envelope and simple capture method make it an attractive option for this task.However,capturing maneuve...The Tethered Space Net Robot(TSNR)is an innovative solution for active space debris capture and removal.Its large envelope and simple capture method make it an attractive option for this task.However,capturing maneuverable debris with the flexible and elastic underactuated net poses significant challenges.To address this,a novel formation control method for the TSNR is proposed through the integration of differential game theory and robust adaptive control in this paper.Specifically,the trajectory of the TSNR is obtained through the solution of a real-time feedback pursuit-evasion game with a dynamic target,where the primary condition is to ensure the stability of the TSNR.Furthermore,to minimize tracking errors and maintain a specific configuration,a robust adaptive formation control scheme with Artificial Potential Field(APF)based on a Finite-Time Convergent Extended State Observer(FTCESO)is investigated.The proposed control method has a key advantage in suppressing complex oscillations by a new adaptive law,thus precisely maintaining the configuration.Finally,numerical simulations are performed to demonstrate the effectiveness of the proposed scheme.展开更多
Aims Screening tree species in tropical rainforest according to their shade tolerance is important to efficiently manage the native trees of economic significance in secondary forest enrichment regimes.The objective o...Aims Screening tree species in tropical rainforest according to their shade tolerance is important to efficiently manage the native trees of economic significance in secondary forest enrichment regimes.The objective of this study was to determine the whole-plant light compensation point(WPLCP)and compare the phenotypic plasticity in relation to growth and carbon allocation of Cariniana legalis and Gallesia integrifolia seedlings under low light availability.Methods Seedlings were cultivated for 77 days under conditions of five photosynthetically active radiation(PAR)(0.02,1.1,2.3,4.5 and 5.9 mol photons m^(−2)day^(−1))in three replicates.Growth and carbon allocation variables were determined.Important Findings Growth rates of C.legalis were higher and lower than those of G.integrifolia under 1.1 and 5.9 mol photons m^(−2)day^(−1),respectively.The WPLCP differed significantly between the two species.In accordance with the criteria of the shade tolerance classification for these two tropical tree species,our results showed that C.legalis had lower WPLCP and phenotypic plasticity in terms of higher growth rates and greater shade tolerance than G.integrifolia.From a practical point of view,we demonstrated that the differential linkage between growth and changing PAR between the two species can become a useful tool for comparing and selecting tree species in forest enrichment projects.展开更多
基金Supported by National 863 High Technology Research and Development Program Foundation of China (No.2006AA-01Z208)Six Talented Eminence Foundation of Jiangsu Province (06-E-043), China+1 种基金Natural Science Foundation of Jiangsu Province, China (No.BK2007236)Scientific Innovation Project for Postgraduates of Universities in Jiangsu Province (CX08B-082Z)
文摘In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-Based Location-Aided Routing(DBLAR) for MANET has been proposed.By tracing the location information of destination nodes and referring to distance change between nodes to adjust route discovery dynamically,the proposed routing algorithm can avoid flooding in the whole networks.Besides,Distance Update Threshold(DUT) is set up to reach the balance between real-time ability and update overhead of location information of nodes,meanwhile,the detection of relative distance vector can achieve the goal of adjusting forwarding condition.Simulation results reveal that DBLAR performs better than LAR1 in terms of packet successful delivery ratio,average end-to-end delay and routing-load,and the set of DUT and relative distance vector has a significant impact on this algorithm.
文摘We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists between both alternative gravity formulas with respect to the distances between mass centers. We conclude a one-to-one mapping of the two gravitational formulas. We don’t need Einstein’s construct of spacetime bending by matter.
基金supported by the National Natural Science Foundation of China(61973160).
文摘Cooperative localization(CL)utilizing multiple unmanned aerial vehides(UAVs)has become the current development trend and research hotspot.The tnditional distance-based CL method.typically uses principle of the spherical intersection to achieve UAV high-precision positioning.However,this distance based CL strategy requires several leader UAVs at the known positions.Thus,a cooperative localization method for leader-follower multiple UA Vs using continuous relative ranging information is proposed in this paper.Aiming at the UAV formation consists of a leader UAV node with the known position and at least a follower UAV that needs to be located.Using the Inertial short-time high-precision relative position constraint and the con-tinuous relative distance constraints with the leader UAV nodes,the closed-form solution of follower UAV's three-dimensional position can be obtained using spherical intersection prin-ciple.On this basis,we derive and construct follower UAV's position observation equation.The:developed strategy requires a single known position leader UAV node to realize high-precision CL,which can efctively solve the taditional distance-based collaborative location problem in case the number of leader UAVs is small.The simulation and experimental results demonstrate that the proposed method significantly improves follower UAV's positioning accuracy,and neglects the limitation of the traditional distance-based CL method on the number of leader UAV nodes at known positions.
基金Supported by China National Science and Technology Major Project(2016ZX05020-006)。
文摘Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.
基金Supported by the National Natural Science Fund of China(11873001 and 12147102)the Fundamental Research Funds for the Central Universities of China(2022CDJXY-002)。
文摘The cosmic distance duality relation(DDR)is constrained by a combination of type-Ⅰa supernovae(SNe la)and strong gravitational lensing(SGL)systems using the deep learning method.To make use of the full SGL data,we reconstruct the luminosity distance from SNeⅠa up to the highest redshift of SGL using deep learning,and then,this luminosity distance is compared with the angular diameter distance obtained from SGL.Considering the influence of the lens mass profile,we constrain the possible violation of the DDR in three lens mass models.The results show that.in the singular isothermal sphere and extended power-law models,the DDR is violated at a high confidence level,with the violation parameterη0=-0.193-0.019+0.021andη0=-0.247-0.013+0.014,respectively.In the power-law model,however,the DDR is verified within a 1σconfidence level,with the violation parameterη0=-0.014-0.045+0.053.Our results demonstrate that the constraints on the DDR strongly depend on the lens mass models.Given a specific lens mass model,the DDR can be constrained at a precision of O(10-2)using deep learning.
基金supported by the National Natural Science Foundation of China(Nos.62222313,62173275,62327809,62303381,and 62303312)in part by the China Postdoctoral Science Foundation(No.2023M732225).
文摘The Tethered Space Net Robot(TSNR)is an innovative solution for active space debris capture and removal.Its large envelope and simple capture method make it an attractive option for this task.However,capturing maneuverable debris with the flexible and elastic underactuated net poses significant challenges.To address this,a novel formation control method for the TSNR is proposed through the integration of differential game theory and robust adaptive control in this paper.Specifically,the trajectory of the TSNR is obtained through the solution of a real-time feedback pursuit-evasion game with a dynamic target,where the primary condition is to ensure the stability of the TSNR.Furthermore,to minimize tracking errors and maintain a specific configuration,a robust adaptive formation control scheme with Artificial Potential Field(APF)based on a Finite-Time Convergent Extended State Observer(FTCESO)is investigated.The proposed control method has a key advantage in suppressing complex oscillations by a new adaptive law,thus precisely maintaining the configuration.Finally,numerical simulations are performed to demonstrate the effectiveness of the proposed scheme.
基金Marcelo S.Mielke gratefully acknowledge CNPq(Brazilian National Council for Scientific and Technological Development)for the award of fellowship of scientific productivity(305477/2018-8).
文摘Aims Screening tree species in tropical rainforest according to their shade tolerance is important to efficiently manage the native trees of economic significance in secondary forest enrichment regimes.The objective of this study was to determine the whole-plant light compensation point(WPLCP)and compare the phenotypic plasticity in relation to growth and carbon allocation of Cariniana legalis and Gallesia integrifolia seedlings under low light availability.Methods Seedlings were cultivated for 77 days under conditions of five photosynthetically active radiation(PAR)(0.02,1.1,2.3,4.5 and 5.9 mol photons m^(−2)day^(−1))in three replicates.Growth and carbon allocation variables were determined.Important Findings Growth rates of C.legalis were higher and lower than those of G.integrifolia under 1.1 and 5.9 mol photons m^(−2)day^(−1),respectively.The WPLCP differed significantly between the two species.In accordance with the criteria of the shade tolerance classification for these two tropical tree species,our results showed that C.legalis had lower WPLCP and phenotypic plasticity in terms of higher growth rates and greater shade tolerance than G.integrifolia.From a practical point of view,we demonstrated that the differential linkage between growth and changing PAR between the two species can become a useful tool for comparing and selecting tree species in forest enrichment projects.
