In this paper,we construct two fully decoupled,second-order semi-discrete numerical schemes for the Boussinesq equations based on the scalar auxiliary variable(SAV)approach.By introducing a scalar auxiliary variable,t...In this paper,we construct two fully decoupled,second-order semi-discrete numerical schemes for the Boussinesq equations based on the scalar auxiliary variable(SAV)approach.By introducing a scalar auxiliary variable,the original Boussinesq system is transformed into an equivalent one.Then we discretize it using the second-order backward di erentiation formula(BDF2)and Crank-Nicolson(CN)to obtain two second-order time-advanced schemes.In both numerical schemes,a pressure-correction method is employed to decouple the velocity and pressure.These two schemes possess the desired property that they can be fully decoupled with satisfying unconditional stability.We rigorously prove both the unconditional stability and unique solvability of the discrete schemes.Furthermore,we provide detailed implementations of the decoupling procedures.Finally,various 2D numerical simulations are performed to verify the accuracy and energy stability of the proposed schemes.展开更多
In this article,the viscoelastic damped was equation in three-dimensional cylindrical domain were studied by using a second-order differential inequality.We proved a Phragm´en-Lindelof alternative results,i.e.,th...In this article,the viscoelastic damped was equation in three-dimensional cylindrical domain were studied by using a second-order differential inequality.We proved a Phragm´en-Lindelof alternative results,i.e.,the smooth solutions either grow or decay exponentially as the distance from the entry section tends to infinity.Our results can be seen as a version of the Saint-Venant principle.展开更多
We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponen...We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.展开更多
In this paper,we construct a new class of efficient and high-order schemes for the Cahn-Hilliard-Navier-Stokes equations with periodic boundary conditions.These schemes are based on two types of scalar auxiliary varia...In this paper,we construct a new class of efficient and high-order schemes for the Cahn-Hilliard-Navier-Stokes equations with periodic boundary conditions.These schemes are based on two types of scalar auxiliary variable approaches.By using a new pressure correction method,the accuracy of the pressure has been greatly improved.Furthermore,one only needs to solve a series of fully decoupled linear equations with constant coefficients at each time step.In addition,we prove the unconditional energy stability of the schemes,rigorously.Finally,plenty of numerical simulations are carried out to verify the convergence rates,stability,and effectiveness of the proposed schemes numerically.展开更多
The complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space is studied.By moment inequality and truncation methods,we establish the...The complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space is studied.By moment inequality and truncation methods,we establish the equivalent conditions of complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space.The results complement the corresponding results in probability space to those for sequences of independent,identically distributed random variables under sublinear expectation space.展开更多
Background Cotton is one of the most important commercial crops after food crops,especially in countries like India,where it’s grown extensively under rainfed conditions.Because of its usage in multiple industries,su...Background Cotton is one of the most important commercial crops after food crops,especially in countries like India,where it’s grown extensively under rainfed conditions.Because of its usage in multiple industries,such as textile,medicine,and automobile industries,it has greater commercial importance.The crop’s performance is greatly influenced by prevailing weather dynamics.As climate changes,assessing how weather changes affect crop performance is essential.Among various techniques that are available,crop models are the most effective and widely used tools for predicting yields.Results This study compares statistical and machine learning models to assess their ability to predict cotton yield across major producing districts of Karnataka,India,utilizing a long-term dataset spanning from 1990 to 2023 that includes yield and weather factors.The artificial neural networks(ANNs)performed superiorly with acceptable yield deviations ranging within±10%during both vegetative stage(F1)and mid stage(F2)for cotton.The model evaluation metrics such as root mean square error(RMSE),normalized root mean square error(nRMSE),and modelling efficiency(EF)were also within the acceptance limits in most districts.Furthermore,the tested ANN model was used to assess the importance of the dominant weather factors influencing crop yield in each district.Specifically,the use of morning relative humidity as an individual parameter and its interaction with maximum and minimum tempera-ture had a major influence on cotton yield in most of the yield predicted districts.These differences highlighted the differential interactions of weather factors in each district for cotton yield formation,highlighting individual response of each weather factor under different soils and management conditions over the major cotton growing districts of Karnataka.Conclusions Compared with statistical models,machine learning models such as ANNs proved higher efficiency in forecasting the cotton yield due to their ability to consider the interactive effects of weather factors on yield forma-tion at different growth stages.This highlights the best suitability of ANNs for yield forecasting in rainfed conditions and for the study on relative impacts of weather factors on yield.Thus,the study aims to provide valuable insights to support stakeholders in planning effective crop management strategies and formulating relevant policies.展开更多
Beyond-visual-range(BVR)air combat threat assessment has attracted wide attention as the support of situation awareness and autonomous decision-making.However,the traditional threat assessment method is flawed in its ...Beyond-visual-range(BVR)air combat threat assessment has attracted wide attention as the support of situation awareness and autonomous decision-making.However,the traditional threat assessment method is flawed in its failure to consider the intention and event of the target,resulting in inaccurate assessment results.In view of this,an integrated threat assessment method is proposed to address the existing problems,such as overly subjective determination of index weight and imbalance of situation.The process and characteristics of BVR air combat are analyzed to establish a threat assessment model in terms of target intention,event,situation,and capability.On this basis,a distributed weight-solving algorithm is proposed to determine index and attribute weight respectively.Then,variable weight and game theory are introduced to effectively deal with the situation imbalance and achieve the combination of subjective and objective.The performance of the model and algorithm is evaluated through multiple simulation experiments.The assessment results demonstrate the accuracy of the proposed method in BVR air combat,indicating its potential practical significance in real air combat scenarios.展开更多
Aiming at the problem of deep surrounding rock instability induced by roadway excavation or mining disturbance,the true triaxial loading system was used to conduct graded cyclic maximum principal stress σ_(1) and int...Aiming at the problem of deep surrounding rock instability induced by roadway excavation or mining disturbance,the true triaxial loading system was used to conduct graded cyclic maximum principal stress σ_(1) and intermediate principal stress σ_(2) tests on sandstone to simulate the effect of mining stress in actual underground engineering.The influences of each principal stress cycle on the mechanical properties,acoustic emission(AE)characteristics,and fracture characteristics of sandstone were analyzed.The damage characteristics of sandstone under true triaxial cyclic loading were studied.Furthermore,the damage constitutive model of rock mass under true triaxial cyclic loading was established based on AE cumulative ringing count.The quantitative investigation was conducted on cumulative-damage changes in circulating sandstone,which elucidated the mechanism of damage deterioration in sandstone subjected to true triaxial cyclic loading.The results show that the influence of the graded cycleσ_(1) on limit maximum principal strain ɛ_(1max) and limit minimum principal strainɛ_(3max) was significantly greater than that of the limit intermediate principal strain ɛ_(2max).Graded cycleσ_(2) had a greater impact onɛ_(2max) and a smaller impact onɛ_(3max).The elasticity modulus of sandstone decreased exponentially with the increased cyclic load amplitude,while the Poisson ratio increased linearly.b of AE showed a trend of increasing,decreasing,slightly fluctuating,and finally decreasing during cyclingσ_(1).b showed a trend of slight fluctuation,large fluctuation,and finally increase during cyclingσ_(2).Sandstone specimens experienced mainly tensile failure,tensile-shear composite failure,and mainly shear failure with increased initialσ_(2) orσ_(3).This was determined by analyzing the rise angle-average frequency of the AE parameter,corresponding to the rock specimens from splitting failure to shear failure.Besides,the mechanical damage behavior of sandstone under true triaxial cyclic loading could be well described by the established constitutive model.At the same time,it was found that the sandstone damage variable decreased with increasedσ_(2) during cyclingσ_(1).The damage variable decreased first and then increased with increasedσ_(3) during cyclingσ_(2).展开更多
International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between a...International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between airlines can affect the quality of a country’s participation in international air transport.In this paper,a multi-objective mixed-integer programming model for traffic rights resource allocation is developed to minimize passenger travel mileages and maximize the number of traffic rights resources allocated to hub airports and competitive carriers.A hybrid heuristic algorithm combining the genetic algorithm and the variable neighborhood search is devised to solve the model.The results show that the optimal allocation scheme aligns with the principle of fairness,indicating that the proposed model can play a certain guiding role in and provide an innovative perspective on traffic rights resource allocation in various countries.展开更多
Functional traits, specifically leaf functional traits, are core-topics to explore importance to the invasion success of invasive plant species. This study aims to address the differences in leaf functional traits and...Functional traits, specifically leaf functional traits, are core-topics to explore importance to the invasion success of invasive plant species. This study aims to address the differences in leaf functional traits and their corresponding variability of the invasive tree staghorn sumac Rhus typhina L. with different invasion success, including lower and higher invasion success, in two climatic regions in North China, including a warm temperate region and a cold temperate region. No significant differences were found for leaf functional traits of staghorn sumac across different invasion success. However, the variability of leaf chlorophyll and nitrogen concentrations of staghorn sumac under higher invasion success were approximately 66.023% and 68.615% higher than those under lower invasion success, respectively. The leaf chlorophyll and nitrogen concentrations of staghorn sumac in the warm temperate region were approximately 18.432% and 16.337% higher than those in cold temperate region, respectively. The variability of specific leaf area of staghorn sumac in warm temperate region was approximately 59.802% higher than that in cold temperate region. Accordingly, leaf chlorophyll and N concentrations as well as specific leaf area of staghorn sumac and their corresponding variability may play an essential role in shaping ecological success of studied invader along a climatic gradient.展开更多
A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homo...A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homogeneity in CFAR reference windows is indicated by a VI-CFAR detector, a switching- CFAR detector is introduced to optimize the performance of the VI-CFAR detector in homogeneous, multiple targets and clutter edge backgrounds. The structure and parameters selection method of the SVI-CFAR detector is presented. Comparisons with classic CFAR detectors and recently proposed detectors are also given. Theoretical analysis and simulation results show that SVICFAR detector maintains the good performance of the VI-CFAR detector in homogeneous and clutter edge backgrounds, while greatly improving the capacity of anti-multi targets.展开更多
Background:Cotton(Gossypium hirsutum L.)is grown for fiber and oil purposes in tropical and sub-tropical areas of the world.Pakistan is the 4th largest producer of cotton.It has a significant contribution in the GDP o...Background:Cotton(Gossypium hirsutum L.)is grown for fiber and oil purposes in tropical and sub-tropical areas of the world.Pakistan is the 4th largest producer of cotton.It has a significant contribution in the GDP of Pakistan.Therefore,the present study was performed to assess the genetic variations and genetic diversity of yield and fiber quality traits in cotton and to analyze the associations present among them.Results:Analysis of variance exhibited significant variation for all studied traits except total number of nodes and the height to node ratio.The phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all studied traits.Plant height,monopodial branches,total number of bolls,lint index,seed index,and seed cotton yield displayed high heritabilities in a broad sense with maximum genetic advanee.Correlation analysis revealed that seed cotton yield had a significant positive association with plant height,the nu mber of monopodial branches,the nu mber of sympodia I branches,ginning outturn(GOT),the number of bolls,seed per boll,seed index,uniformity index,the number of sympodial branches,reflectance,and seed index at the genotypic level while a significant positive relationship was observed with plant height,the number of sympodial branches,boll number,and GOT.Plant height,monopodial branches,GOT,boll weight,seeds per boll,and short fiber index exerted direct positive effects on seed cotton yield.The first 6 principal component analysis(PCs)out of the total fourteen PCs displayed eigenvalues(>1)and had maximum share to total variability(82.79%).The attributes that had maximum share to total divergence in eluded plant height,uniformity index,the nu mber of sympodial branches,seed per boll,GOT,seed cotton yield,and short fiber index.Conclusion:The genotype AA-802,IUB-13,FH-159,FH-458,and CIM-595 were genetically diverse for most of the yield and fiber quality traits and could be utilized for the selection of better performing genotypes for further improvement.展开更多
Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture ...Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture in this region.From an analysis of recent rainfall conditions in West Africa,FAO(2001) concluded that a long-term change in rainfall has occurred in the semi-arid and sub-humid zones of West Africa.Thus,this study aims at assessing the vulnerability of crop yields to inter-annual variability in rainfall in sub-Saharan African countries taking Nigeria as a case study.A time series of the averaged value of the 12-Month Weighted Anomaly Standardized Precipita-展开更多
The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump ari...The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.展开更多
The delay vehicles experience at signalized intersections is one of the most important indicators for measuring intersection performance. The interpretation of delay variability evolvement at intersections gives a com...The delay vehicles experience at signalized intersections is one of the most important indicators for measuring intersection performance. The interpretation of delay variability evolvement at intersections gives a comprehensive insight into arterial traffic operation. Thus, an analytical model is proposed to investigate delay variability at coordinated intersections. Two different flow rates are assumed for both effective red and green periods in cumulative curves, through which the effect of signal coordination is incorporated in delay estimation. Then, an analogy of Markov chain process is used to explore the mechanism of stochastic overflow queue at signalized intersections. Numerical case studies show that with the decrease of arrival proportions during green, the shape of delay distribution in both undersaturation and oversaturation cases shifts faster towards higher values, implying that the coordination effect between paired intersections has a great effect on the delay distribution. As for delay fluctuation range, favorable coordination is demonstrated to be able to weaken the variability of delay estimates especially for undersaturation conditions.展开更多
Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local o...Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.展开更多
In this paper,we investigate the complete convergence and complete moment conver-gence for weighted sums of arrays of rowwise asymptotically negatively associated(ANA)random variables,without assuming identical distri...In this paper,we investigate the complete convergence and complete moment conver-gence for weighted sums of arrays of rowwise asymptotically negatively associated(ANA)random variables,without assuming identical distribution.The obtained results not only extend those of An and Yuan[1]and Shen et al.[2]to the case of ANA random variables,but also partially improve them.展开更多
At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The who...At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The whole BFGSP skew-plates is placed on a variable visco-elastic foundation(VEF)in the hygro-thermal environment and subjected to the blast load.The BFGSP skew-plate thickness is permitted to vary non-linearly over both the length and width of the skew-plate,thereby faithfully representing the real behavior of the structure itself.The analysis is based on a four-node planar quadrilateral element with eight degrees of freedom per node,which is approximated using Lagrange Q_(4)shape function and C^(1)level non-conforming Hermite shape function based on refined higher-order shear deformation plate theory.The forced vibration parameters of the non-uniform thickness BFGSP skew-plate are fully determined using Hamilton's principle and the Newmark-βdirect integration technique.Accuracy of the calculation program is validated by comparing its numerical results with those from reputable sources.Furthermore,a thorough assessment is conducted to determine the impact of various parameters on the free and forced vibration responses of the non-uniform thickness BFGSP skew-plate.The findings of the paper may be used in the development of civil and military structures in situations that are prone to exceptional forces,such as explosions and impacts load.展开更多
A novel variable step-size modified super-exponential iteration(MSEI)decision feedback blind equalization(DFE)algorithm with second-order digital phase-locked loop is put forward to improve the convergence performance...A novel variable step-size modified super-exponential iteration(MSEI)decision feedback blind equalization(DFE)algorithm with second-order digital phase-locked loop is put forward to improve the convergence performance of super-exponential iteration DFE algorithm.Based on the MSEI-DFE algorithm,it is first proposed to develop an error function as an improvement to the error function of MSEI,which effectively achieves faster convergence speed of the algorithm.Subsequently,a hyperbolic tangent function variable step-size algorithm is developed considering the high variation rate of the hyperbolic tangent function around zero,so as to further improve the convergence speed of the algorithm.In the end,a second-order digital phase-locked loop is introduced into the decision feedback equalizer to track and compensate for the phase rotation of equalizer input signals.For the multipath underwater acoustic channel with mixed phase and phase rotation,quadrature phase shift keying(QPSK)and 16 quadrature amplitude modulation(16QAM)modulated signals are used in the computer simulation of the algorithm in terms of convergence and carrier recovery performance.The results show that the proposed algorithm can considerably improve convergence speed and steady-state error,make effective compensation for phase rotation,and efficiently facilitate carrier recovery.展开更多
Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 ...Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 to 2022.The results indicated that the reconstructed annual mean wind speed and the standard deviation of the annual mean wind speed,utilizing various climate variability indices,exhibited similar spatial modes to the reanalysis data,with spatial correlation coefficients of 0.99 and 0.94,respectively.In the reconstruction of six major wind power installed capacity provinces/autonomous regions in China,the effects were notably good for Hebei and Shanxi provinces,with the correlation coefficients for the interannual regional average wind speed time series being 0.65 and 0.64,respectively.The reconstruction effects of surface wind speed differed across seasons,with spring and summer reconstructions showing the highest correlation with reanalysis data.The correlation coefficients for all seasons across most regions in China ranged between 0.4 and 0.8.Among the reconstructed seasonal wind speeds for the six provinces/autonomous regions,Shanxi Province in spring exhibited the highest correlation with the reanalysis,with a coefficient of 0.61.The large-scale climate variability indices showed good reconstruction effects on the annual mean wind speed in China,and could explain the interannual variability trends of surface wind speed in most regions of China,particularly in the main wind energy provinces/autonomous regions.展开更多
基金Supported by Research Project Supported by Shanxi Scholarship Council of China(2021-029)International Cooperation Base and Platform Project of Shanxi Province(202104041101019)+2 种基金Basic Research Plan of Shanxi Province(202203021211129)Shanxi Province Natural Science Research(202203021212249)Special/Youth Foundation of Taiyuan University of Technology(2022QN101)。
文摘In this paper,we construct two fully decoupled,second-order semi-discrete numerical schemes for the Boussinesq equations based on the scalar auxiliary variable(SAV)approach.By introducing a scalar auxiliary variable,the original Boussinesq system is transformed into an equivalent one.Then we discretize it using the second-order backward di erentiation formula(BDF2)and Crank-Nicolson(CN)to obtain two second-order time-advanced schemes.In both numerical schemes,a pressure-correction method is employed to decouple the velocity and pressure.These two schemes possess the desired property that they can be fully decoupled with satisfying unconditional stability.We rigorously prove both the unconditional stability and unique solvability of the discrete schemes.Furthermore,we provide detailed implementations of the decoupling procedures.Finally,various 2D numerical simulations are performed to verify the accuracy and energy stability of the proposed schemes.
基金Supported by the Guangdong Natural Science foundation(2023A1515012044)Special Project of Guangdong Province in Key Fields of Ordinary Colleges and Universities(2023ZDZX4069)+1 种基金the Research Team of Guangzhou Huashang College(2021HSKT01)Guangzhou Huashang College’s Characteristic Research Projects(2024HSTS09)。
文摘In this article,the viscoelastic damped was equation in three-dimensional cylindrical domain were studied by using a second-order differential inequality.We proved a Phragm´en-Lindelof alternative results,i.e.,the smooth solutions either grow or decay exponentially as the distance from the entry section tends to infinity.Our results can be seen as a version of the Saint-Venant principle.
基金supported by the National Natural Science Foundation of China(Grant No.11971486)。
文摘We consider a single server constant retrial queue,in which a state-dependent service policy is used to control the service rate.Customer arrival follows Poisson process,while service time and retrial time are exponential distributions.Whenever the server is available,it admits the retrial customers into service based on a first-come first-served rule.The service rate adjusts in real-time based on the retrial queue length.An iterative algorithm is proposed to numerically solve the personal optimal problem in the fully observable scenario.Furthermore,we investigate the impact of parameters on the social optimal threshold.The effectiveness of the results is illustrated by two examples.
基金Supported by the Research Project Supported of Shanxi Scholarship Council of China(No.2021-029)Shanxi Provincial International Cooperation Base and Platform Project(202104041101019)Shanxi Province Natural Science Research(202203021211129)。
文摘In this paper,we construct a new class of efficient and high-order schemes for the Cahn-Hilliard-Navier-Stokes equations with periodic boundary conditions.These schemes are based on two types of scalar auxiliary variable approaches.By using a new pressure correction method,the accuracy of the pressure has been greatly improved.Furthermore,one only needs to solve a series of fully decoupled linear equations with constant coefficients at each time step.In addition,we prove the unconditional energy stability of the schemes,rigorously.Finally,plenty of numerical simulations are carried out to verify the convergence rates,stability,and effectiveness of the proposed schemes numerically.
基金supported by Doctoral Scientific Research Starting Foundation of Jingdezhen Ceramic University(Grant No.102/01003002031)Re-accompanying Funding Project of Academic Achievements of Jingdezhen Ceramic University(Grant Nos.215/20506277,215/20506341)。
文摘The complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space is studied.By moment inequality and truncation methods,we establish the equivalent conditions of complete convergence for weighted sums of sequences of independent,identically distributed random variables under sublinear expectation space.The results complement the corresponding results in probability space to those for sequences of independent,identically distributed random variables under sublinear expectation space.
基金funded through India Meteorological Department,New Delhi,India under the Forecasting Agricultural output using Space,Agrometeorol ogy and Land based observations(FASAL)project and fund number:No.ASC/FASAL/KT-11/01/HQ-2010.
文摘Background Cotton is one of the most important commercial crops after food crops,especially in countries like India,where it’s grown extensively under rainfed conditions.Because of its usage in multiple industries,such as textile,medicine,and automobile industries,it has greater commercial importance.The crop’s performance is greatly influenced by prevailing weather dynamics.As climate changes,assessing how weather changes affect crop performance is essential.Among various techniques that are available,crop models are the most effective and widely used tools for predicting yields.Results This study compares statistical and machine learning models to assess their ability to predict cotton yield across major producing districts of Karnataka,India,utilizing a long-term dataset spanning from 1990 to 2023 that includes yield and weather factors.The artificial neural networks(ANNs)performed superiorly with acceptable yield deviations ranging within±10%during both vegetative stage(F1)and mid stage(F2)for cotton.The model evaluation metrics such as root mean square error(RMSE),normalized root mean square error(nRMSE),and modelling efficiency(EF)were also within the acceptance limits in most districts.Furthermore,the tested ANN model was used to assess the importance of the dominant weather factors influencing crop yield in each district.Specifically,the use of morning relative humidity as an individual parameter and its interaction with maximum and minimum tempera-ture had a major influence on cotton yield in most of the yield predicted districts.These differences highlighted the differential interactions of weather factors in each district for cotton yield formation,highlighting individual response of each weather factor under different soils and management conditions over the major cotton growing districts of Karnataka.Conclusions Compared with statistical models,machine learning models such as ANNs proved higher efficiency in forecasting the cotton yield due to their ability to consider the interactive effects of weather factors on yield forma-tion at different growth stages.This highlights the best suitability of ANNs for yield forecasting in rainfed conditions and for the study on relative impacts of weather factors on yield.Thus,the study aims to provide valuable insights to support stakeholders in planning effective crop management strategies and formulating relevant policies.
基金National Natural Science Foundation of China(62006193,62103338)Aeronautical Science Foundation of China(2022Z023053001)+1 种基金Key Research and Development Program of Shaanxi Province(2024GX-YBXM-115)Fundamental Research Funds for the Central Universities(D5000230150)。
文摘Beyond-visual-range(BVR)air combat threat assessment has attracted wide attention as the support of situation awareness and autonomous decision-making.However,the traditional threat assessment method is flawed in its failure to consider the intention and event of the target,resulting in inaccurate assessment results.In view of this,an integrated threat assessment method is proposed to address the existing problems,such as overly subjective determination of index weight and imbalance of situation.The process and characteristics of BVR air combat are analyzed to establish a threat assessment model in terms of target intention,event,situation,and capability.On this basis,a distributed weight-solving algorithm is proposed to determine index and attribute weight respectively.Then,variable weight and game theory are introduced to effectively deal with the situation imbalance and achieve the combination of subjective and objective.The performance of the model and algorithm is evaluated through multiple simulation experiments.The assessment results demonstrate the accuracy of the proposed method in BVR air combat,indicating its potential practical significance in real air combat scenarios.
基金Project(2022m07020007)supported by the Key Research and Development Projects of Anhui Province,ChinaProjects(52174102,52074006,51404011,51874002,51974009)supported by the National Natural Science Foundation of China+1 种基金Project(2024cx1017)supported by the Graduate Innovation Fund of Anhui University of Science and Technology,ChinaProject(2024AH040067)supported by the Natural Science Research Project of Anhui Educational Committee,China。
文摘Aiming at the problem of deep surrounding rock instability induced by roadway excavation or mining disturbance,the true triaxial loading system was used to conduct graded cyclic maximum principal stress σ_(1) and intermediate principal stress σ_(2) tests on sandstone to simulate the effect of mining stress in actual underground engineering.The influences of each principal stress cycle on the mechanical properties,acoustic emission(AE)characteristics,and fracture characteristics of sandstone were analyzed.The damage characteristics of sandstone under true triaxial cyclic loading were studied.Furthermore,the damage constitutive model of rock mass under true triaxial cyclic loading was established based on AE cumulative ringing count.The quantitative investigation was conducted on cumulative-damage changes in circulating sandstone,which elucidated the mechanism of damage deterioration in sandstone subjected to true triaxial cyclic loading.The results show that the influence of the graded cycleσ_(1) on limit maximum principal strain ɛ_(1max) and limit minimum principal strainɛ_(3max) was significantly greater than that of the limit intermediate principal strain ɛ_(2max).Graded cycleσ_(2) had a greater impact onɛ_(2max) and a smaller impact onɛ_(3max).The elasticity modulus of sandstone decreased exponentially with the increased cyclic load amplitude,while the Poisson ratio increased linearly.b of AE showed a trend of increasing,decreasing,slightly fluctuating,and finally decreasing during cyclingσ_(1).b showed a trend of slight fluctuation,large fluctuation,and finally increase during cyclingσ_(2).Sandstone specimens experienced mainly tensile failure,tensile-shear composite failure,and mainly shear failure with increased initialσ_(2) orσ_(3).This was determined by analyzing the rise angle-average frequency of the AE parameter,corresponding to the rock specimens from splitting failure to shear failure.Besides,the mechanical damage behavior of sandstone under true triaxial cyclic loading could be well described by the established constitutive model.At the same time,it was found that the sandstone damage variable decreased with increasedσ_(2) during cyclingσ_(1).The damage variable decreased first and then increased with increasedσ_(3) during cyclingσ_(2).
基金supported by the National Natural Science Foundation of Chinathe Civil Aviation Administration of China (U2333206).
文摘International freedom of the air(traffic rights)is a key resource for airlines to carry out international air transport business.An efficient and reasonable traffic right resource allocation within a country between airlines can affect the quality of a country’s participation in international air transport.In this paper,a multi-objective mixed-integer programming model for traffic rights resource allocation is developed to minimize passenger travel mileages and maximize the number of traffic rights resources allocated to hub airports and competitive carriers.A hybrid heuristic algorithm combining the genetic algorithm and the variable neighborhood search is devised to solve the model.The results show that the optimal allocation scheme aligns with the principle of fairness,indicating that the proposed model can play a certain guiding role in and provide an innovative perspective on traffic rights resource allocation in various countries.
基金Project(31300343)supported by the National Natural Science Foundation of ChinaProject(Y20160023)supported by Open Science Research Fund of State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,China+1 种基金Project supported by Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),ChinaProject supported by Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment
文摘Functional traits, specifically leaf functional traits, are core-topics to explore importance to the invasion success of invasive plant species. This study aims to address the differences in leaf functional traits and their corresponding variability of the invasive tree staghorn sumac Rhus typhina L. with different invasion success, including lower and higher invasion success, in two climatic regions in North China, including a warm temperate region and a cold temperate region. No significant differences were found for leaf functional traits of staghorn sumac across different invasion success. However, the variability of leaf chlorophyll and nitrogen concentrations of staghorn sumac under higher invasion success were approximately 66.023% and 68.615% higher than those under lower invasion success, respectively. The leaf chlorophyll and nitrogen concentrations of staghorn sumac in the warm temperate region were approximately 18.432% and 16.337% higher than those in cold temperate region, respectively. The variability of specific leaf area of staghorn sumac in warm temperate region was approximately 59.802% higher than that in cold temperate region. Accordingly, leaf chlorophyll and N concentrations as well as specific leaf area of staghorn sumac and their corresponding variability may play an essential role in shaping ecological success of studied invader along a climatic gradient.
基金supported by the National Natural Science Foundation of China(61102158)the China Postdoctoral Science Foundation(2011M500667)
文摘A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homogeneity in CFAR reference windows is indicated by a VI-CFAR detector, a switching- CFAR detector is introduced to optimize the performance of the VI-CFAR detector in homogeneous, multiple targets and clutter edge backgrounds. The structure and parameters selection method of the SVI-CFAR detector is presented. Comparisons with classic CFAR detectors and recently proposed detectors are also given. Theoretical analysis and simulation results show that SVICFAR detector maintains the good performance of the VI-CFAR detector in homogeneous and clutter edge backgrounds, while greatly improving the capacity of anti-multi targets.
基金Department of Plant Breeding and Genetics,University of Agriculture Faisalabad,Faisalabad-Pakistan.
文摘Background:Cotton(Gossypium hirsutum L.)is grown for fiber and oil purposes in tropical and sub-tropical areas of the world.Pakistan is the 4th largest producer of cotton.It has a significant contribution in the GDP of Pakistan.Therefore,the present study was performed to assess the genetic variations and genetic diversity of yield and fiber quality traits in cotton and to analyze the associations present among them.Results:Analysis of variance exhibited significant variation for all studied traits except total number of nodes and the height to node ratio.The phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all studied traits.Plant height,monopodial branches,total number of bolls,lint index,seed index,and seed cotton yield displayed high heritabilities in a broad sense with maximum genetic advanee.Correlation analysis revealed that seed cotton yield had a significant positive association with plant height,the nu mber of monopodial branches,the nu mber of sympodia I branches,ginning outturn(GOT),the number of bolls,seed per boll,seed index,uniformity index,the number of sympodial branches,reflectance,and seed index at the genotypic level while a significant positive relationship was observed with plant height,the number of sympodial branches,boll number,and GOT.Plant height,monopodial branches,GOT,boll weight,seeds per boll,and short fiber index exerted direct positive effects on seed cotton yield.The first 6 principal component analysis(PCs)out of the total fourteen PCs displayed eigenvalues(>1)and had maximum share to total variability(82.79%).The attributes that had maximum share to total divergence in eluded plant height,uniformity index,the nu mber of sympodial branches,seed per boll,GOT,seed cotton yield,and short fiber index.Conclusion:The genotype AA-802,IUB-13,FH-159,FH-458,and CIM-595 were genetically diverse for most of the yield and fiber quality traits and could be utilized for the selection of better performing genotypes for further improvement.
文摘Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture in this region.From an analysis of recent rainfall conditions in West Africa,FAO(2001) concluded that a long-term change in rainfall has occurred in the semi-arid and sub-humid zones of West Africa.Thus,this study aims at assessing the vulnerability of crop yields to inter-annual variability in rainfall in sub-Saharan African countries taking Nigeria as a case study.A time series of the averaged value of the 12-Month Weighted Anomaly Standardized Precipita-
文摘The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.
基金Project(51278455)supported by the National Natural Science Foundation of ChinaProject(2012M521175)supported by the National Science Foundation for Post-doctoral Scientists of ChinaProject(Bsh1202056)supported by and the Excellent Postdoctoral Science Foundation of Zhejiang Province,China
文摘The delay vehicles experience at signalized intersections is one of the most important indicators for measuring intersection performance. The interpretation of delay variability evolvement at intersections gives a comprehensive insight into arterial traffic operation. Thus, an analytical model is proposed to investigate delay variability at coordinated intersections. Two different flow rates are assumed for both effective red and green periods in cumulative curves, through which the effect of signal coordination is incorporated in delay estimation. Then, an analogy of Markov chain process is used to explore the mechanism of stochastic overflow queue at signalized intersections. Numerical case studies show that with the decrease of arrival proportions during green, the shape of delay distribution in both undersaturation and oversaturation cases shifts faster towards higher values, implying that the coordination effect between paired intersections has a great effect on the delay distribution. As for delay fluctuation range, favorable coordination is demonstrated to be able to weaken the variability of delay estimates especially for undersaturation conditions.
文摘Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.
基金National Natural Science Foundation of China (Grant Nos.12061028, 71871046)Support Program of the Guangxi China Science Foundation (Grant No.2018GXNSFAA281011)。
文摘In this paper,we investigate the complete convergence and complete moment conver-gence for weighted sums of arrays of rowwise asymptotically negatively associated(ANA)random variables,without assuming identical distribution.The obtained results not only extend those of An and Yuan[1]and Shen et al.[2]to the case of ANA random variables,but also partially improve them.
文摘At the first time,the finite element method was used to model and analyze the free vibration and transient response of non-uniform thickness bi-directional functionally graded sandwich porous(BFGSP)skew plates.The whole BFGSP skew-plates is placed on a variable visco-elastic foundation(VEF)in the hygro-thermal environment and subjected to the blast load.The BFGSP skew-plate thickness is permitted to vary non-linearly over both the length and width of the skew-plate,thereby faithfully representing the real behavior of the structure itself.The analysis is based on a four-node planar quadrilateral element with eight degrees of freedom per node,which is approximated using Lagrange Q_(4)shape function and C^(1)level non-conforming Hermite shape function based on refined higher-order shear deformation plate theory.The forced vibration parameters of the non-uniform thickness BFGSP skew-plate are fully determined using Hamilton's principle and the Newmark-βdirect integration technique.Accuracy of the calculation program is validated by comparing its numerical results with those from reputable sources.Furthermore,a thorough assessment is conducted to determine the impact of various parameters on the free and forced vibration responses of the non-uniform thickness BFGSP skew-plate.The findings of the paper may be used in the development of civil and military structures in situations that are prone to exceptional forces,such as explosions and impacts load.
基金supported by the National Natural Science Foundation of China(61671461)。
文摘A novel variable step-size modified super-exponential iteration(MSEI)decision feedback blind equalization(DFE)algorithm with second-order digital phase-locked loop is put forward to improve the convergence performance of super-exponential iteration DFE algorithm.Based on the MSEI-DFE algorithm,it is first proposed to develop an error function as an improvement to the error function of MSEI,which effectively achieves faster convergence speed of the algorithm.Subsequently,a hyperbolic tangent function variable step-size algorithm is developed considering the high variation rate of the hyperbolic tangent function around zero,so as to further improve the convergence speed of the algorithm.In the end,a second-order digital phase-locked loop is introduced into the decision feedback equalizer to track and compensate for the phase rotation of equalizer input signals.For the multipath underwater acoustic channel with mixed phase and phase rotation,quadrature phase shift keying(QPSK)and 16 quadrature amplitude modulation(16QAM)modulated signals are used in the computer simulation of the algorithm in terms of convergence and carrier recovery performance.The results show that the proposed algorithm can considerably improve convergence speed and steady-state error,make effective compensation for phase rotation,and efficiently facilitate carrier recovery.
基金the National Natural Science Foundation of China(42176243)。
文摘Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 to 2022.The results indicated that the reconstructed annual mean wind speed and the standard deviation of the annual mean wind speed,utilizing various climate variability indices,exhibited similar spatial modes to the reanalysis data,with spatial correlation coefficients of 0.99 and 0.94,respectively.In the reconstruction of six major wind power installed capacity provinces/autonomous regions in China,the effects were notably good for Hebei and Shanxi provinces,with the correlation coefficients for the interannual regional average wind speed time series being 0.65 and 0.64,respectively.The reconstruction effects of surface wind speed differed across seasons,with spring and summer reconstructions showing the highest correlation with reanalysis data.The correlation coefficients for all seasons across most regions in China ranged between 0.4 and 0.8.Among the reconstructed seasonal wind speeds for the six provinces/autonomous regions,Shanxi Province in spring exhibited the highest correlation with the reanalysis,with a coefficient of 0.61.The large-scale climate variability indices showed good reconstruction effects on the annual mean wind speed in China,and could explain the interannual variability trends of surface wind speed in most regions of China,particularly in the main wind energy provinces/autonomous regions.
