Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structu...Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification （SSI） method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method.展开更多
This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity. We propose a concept of ＂desirable pair of upper-lower solutions＂, through which a...This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity. We propose a concept of ＂desirable pair of upper-lower solutions＂, through which a subset can be constructed. We then apply the Schauder＇s fixed point theorem to some appropriate operator in this subset to obtain the existence of the travelling wave fronts.展开更多
The existence of periodic solutions for periodic reaction-diffusion systems with time delay by the periodic upper-lower solution method is investigated. Some methods for proving the uniqueness and the stability of the...The existence of periodic solutions for periodic reaction-diffusion systems with time delay by the periodic upper-lower solution method is investigated. Some methods for proving the uniqueness and the stability of the periodic solution are also given. Two examples are used to show how to use our methods.展开更多
Granular computing is a very hot research field in recent years. In our previous work an algebraic quotient space model was proposed,where the quotient structure could not be deduced if the granulation was based on an...Granular computing is a very hot research field in recent years. In our previous work an algebraic quotient space model was proposed,where the quotient structure could not be deduced if the granulation was based on an equivalence relation. In this paper,definitions were given and formulas of the lower quotient congruence and upper quotient congruence were calculated to roughly represent the quotient structure. Then the accuracy and roughness were defined to measure the quotient structure in quantification. Finally,a numerical example was given to demonstrate that the rough representation and measuring methods are efficient and applicable. The work has greatly enriched the algebraic quotient space model and granular computing theory.展开更多
In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use th...In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use the idea of changing variables to transform the model into a uniform dispersal one.Then the existence and uniqueness of positive stationary solution to the model can be verified by the squeezing argument,where the solution plays a crucial role in later analyses.Moreover,the asymptotic behavior of solutions to the model is obtained by the upper-lower solutions method.The result indicates that the solutions of the model converge to the corresponding positive stationary solution locally uniformly in one dimension as time goes to infinity.展开更多
In Orlicz-Bochner sequence spaces endowed with Orlicz norm and Luxemburg norm, points of lower monotonicity, upper monotonicity, lower local uniform monotonicity and upper local uniform monotonicity are characterized.
In this paper, we obtain some other properties of the majorly efficient points and solutions of the multiobjective optimization presellted in two previous papers of Hu. By decomposing the major cone, which is non-poin...In this paper, we obtain some other properties of the majorly efficient points and solutions of the multiobjective optimization presellted in two previous papers of Hu. By decomposing the major cone, which is non-pointed, non-convex and non-closed into a finite union of disjoint strictly supported pointed convex cones, we discuss the continuous perturbations of the decision space. Several sufficient conditions for the continuity of the sets of majorly efficiellt points and solutions are given.展开更多
The fiber grouted material can reinforce the tension strength, shear strength as well as the index of fracture ductile, and remarkably improve the endurance of pre-stressed anchor rope under long-time loading. As a re...The fiber grouted material can reinforce the tension strength, shear strength as well as the index of fracture ductile, and remarkably improve the endurance of pre-stressed anchor rope under long-time loading. As a result, it has the better application foreground. Based on the shear log model and Hashin-Shtrikman upper and lower limited theorem, we have studied the mechanism of fiber grouted material applied in pre-stressed anchor rope and material property, and analyzed the effect of resistance strength of bond, resistance distribution of anchor section and the loading-deformation relationship of anchor body.展开更多
The existence of global solution and the blow-up problem for a model of nuclear reactorsare discussed by using the upper-lower solution and energy estimate methods; asymptoticbehavior of global solution is also discus...The existence of global solution and the blow-up problem for a model of nuclear reactorsare discussed by using the upper-lower solution and energy estimate methods; asymptoticbehavior of global solution is also discussed with the aid of L_p estimate and semigroupmethod for this model. Nice results, which explain the phenomenon of nuclear reactorsbetter, are obtained.展开更多
This paper is concerned with the existence of traveling wave solutions in a reaction-diffusion predator-prey system with Beddington-DeAngelis functional response and a discrete time delay. By introducing a partial qua...This paper is concerned with the existence of traveling wave solutions in a reaction-diffusion predator-prey system with Beddington-DeAngelis functional response and a discrete time delay. By introducing a partial quasi-monotonicity condition and constructing a pair of upper-lower solutions, we establish the existence of traveling wave solutions. Moreover, a numerical simulation is carried out to illustrate the theoretical results.展开更多
An epidemic model with vaccination and nonlocal diffusion is proposed, and the existence of traveling wave solutions of this model is studied. By the cross-iteration scheme companied with a pair of upper and lower sol...An epidemic model with vaccination and nonlocal diffusion is proposed, and the existence of traveling wave solutions of this model is studied. By the cross-iteration scheme companied with a pair of upper and lower solutions and Schauder's fixed point theorem,sufficient conditions are obtained for the existence of a traveling wave solution connecting the disease-free steady state and the endemic steady state.展开更多
This paper deals with the existence of traveling wave solutions in a three-species food-chain model with spatial diffusion and time delays due to gestation and negative feedback. By using a cross iteration scheme and ...This paper deals with the existence of traveling wave solutions in a three-species food-chain model with spatial diffusion and time delays due to gestation and negative feedback. By using a cross iteration scheme and Schauder＇s fixed point theorem, we reduce the existence of traveling wave solutions to the existence of a pair of upper-lower solutions. By constructing a pair of upper-lower solutions, we derive the existence of a traveling wave solution connecting the trivial steady state and the positive steady state. Numerical simulations are carried out to illustrate the main results. In particular, our results extend and improve some known results.展开更多
This paper is concerned with the existence of traveling wave solutions in a reaction- diffusion predator-prey system with nonlocal delays. By introducing a partially expo- nential quasi-monotonicity condition and a ne...This paper is concerned with the existence of traveling wave solutions in a reaction- diffusion predator-prey system with nonlocal delays. By introducing a partially expo- nential quasi-monotonicity condition and a new cross iteration scheme, we reduce the existence of traveling wave solutions to the existence of a pair of upper-lower solutions. By constructing a desirable pair of upper-lower solutions, we establish the existence of traveling wave solutions. Finally, some numerical examples are carried out to illustrate the theoretical results.展开更多
In this paper, another form of KKM type theorem on generalized convex spaces is obtained and the problems of von Neumann-Fan type sup inf sup inequalities and variational inequalities are discussed for their applicati...In this paper, another form of KKM type theorem on generalized convex spaces is obtained and the problems of von Neumann-Fan type sup inf sup inequalities and variational inequalities are discussed for their applications.The main results improve and generalize the corresponding results in previous papers.展开更多
This paper is concerned with the minimal wave speed in a diffusive epidemic model with nonlocal delays.We define a threshold.By presenting the existence and the nonexistence of traveling wave solutions for all positiv...This paper is concerned with the minimal wave speed in a diffusive epidemic model with nonlocal delays.We define a threshold.By presenting the existence and the nonexistence of traveling wave solutions for all positive wave speed,we confirm that the threshold is the minimal wave speed of traveling wave solutions,which models that the infective invades the habitat of the susceptible.For some cases,it is proven that spatial nonlocality may increase the propagation threshold while time delay decreases the threshold.展开更多
基金National Natural Science Foundation of China under Grant No.51338001Natural Science Foundation of China under Grant Nos.51178028 and 51422801+2 种基金the Fundamental Research Funds for the Central Universities under Grant No.2014YJS087Program for New Century Excellent Talents in University under Grant No.NCET-11-0571111 Project of China under Grant No.B13002
文摘Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification （SSI） method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method.
基金Supported by the National Natural Science Foundation of China(No.19971032)the second author is supported by Natural Science Foundation of Canadaby a Petro Canada Young Innovator Award.
文摘This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systems with partial quasi-monotonicity. We propose a concept of ＂desirable pair of upper-lower solutions＂, through which a subset can be constructed. We then apply the Schauder＇s fixed point theorem to some appropriate operator in this subset to obtain the existence of the travelling wave fronts.
基金This research is supported by the National Natural Science Foundation of China (No.19671005, 19971004).
文摘The existence of periodic solutions for periodic reaction-diffusion systems with time delay by the periodic upper-lower solution method is investigated. Some methods for proving the uniqueness and the stability of the periodic solution are also given. Two examples are used to show how to use our methods.
基金Supported by the National Natural Science Foundation of China(No.61772031)the Special Energy Saving Foundation of Changsha,Hunan Province in 2017
文摘Granular computing is a very hot research field in recent years. In our previous work an algebraic quotient space model was proposed,where the quotient structure could not be deduced if the granulation was based on an equivalence relation. In this paper,definitions were given and formulas of the lower quotient congruence and upper quotient congruence were calculated to roughly represent the quotient structure. Then the accuracy and roughness were defined to measure the quotient structure in quantification. Finally,a numerical example was given to demonstrate that the rough representation and measuring methods are efficient and applicable. The work has greatly enriched the algebraic quotient space model and granular computing theory.
基金supported by the National Natural Science Foundation of China (Nos.12301101,12101121)the Guangdong Basic and Applied Basic Research Foundation (Nos.2022A1515110019,2020A1515110585)。
文摘In this paper,we study the asymptotic dynamics of a single-species model with resource-dependent dispersal in one dimension.To overcome the analytical difficulties brought by the resource-dependent dispersal,we use the idea of changing variables to transform the model into a uniform dispersal one.Then the existence and uniqueness of positive stationary solution to the model can be verified by the squeezing argument,where the solution plays a crucial role in later analyses.Moreover,the asymptotic behavior of solutions to the model is obtained by the upper-lower solutions method.The result indicates that the solutions of the model converge to the corresponding positive stationary solution locally uniformly in one dimension as time goes to infinity.
文摘In Orlicz-Bochner sequence spaces endowed with Orlicz norm and Luxemburg norm, points of lower monotonicity, upper monotonicity, lower local uniform monotonicity and upper local uniform monotonicity are characterized.
文摘In this paper, we obtain some other properties of the majorly efficient points and solutions of the multiobjective optimization presellted in two previous papers of Hu. By decomposing the major cone, which is non-pointed, non-convex and non-closed into a finite union of disjoint strictly supported pointed convex cones, we discuss the continuous perturbations of the decision space. Several sufficient conditions for the continuity of the sets of majorly efficiellt points and solutions are given.
文摘The fiber grouted material can reinforce the tension strength, shear strength as well as the index of fracture ductile, and remarkably improve the endurance of pre-stressed anchor rope under long-time loading. As a result, it has the better application foreground. Based on the shear log model and Hashin-Shtrikman upper and lower limited theorem, we have studied the mechanism of fiber grouted material applied in pre-stressed anchor rope and material property, and analyzed the effect of resistance strength of bond, resistance distribution of anchor section and the loading-deformation relationship of anchor body.
文摘The existence of global solution and the blow-up problem for a model of nuclear reactorsare discussed by using the upper-lower solution and energy estimate methods; asymptoticbehavior of global solution is also discussed with the aid of L_p estimate and semigroupmethod for this model. Nice results, which explain the phenomenon of nuclear reactorsbetter, are obtained.
文摘This paper is concerned with the existence of traveling wave solutions in a reaction-diffusion predator-prey system with Beddington-DeAngelis functional response and a discrete time delay. By introducing a partial quasi-monotonicity condition and constructing a pair of upper-lower solutions, we establish the existence of traveling wave solutions. Moreover, a numerical simulation is carried out to illustrate the theoretical results.
基金Supported by the National Natural Science Foundation of China（11371368） Supported by the Natural Science Foundation of Hebei Province（A2013506012） Supported by the Foundation of Shijiazhuang Mechanical Engineering College（JCB1201, YJJXM13008）
文摘An epidemic model with vaccination and nonlocal diffusion is proposed, and the existence of traveling wave solutions of this model is studied. By the cross-iteration scheme companied with a pair of upper and lower solutions and Schauder's fixed point theorem,sufficient conditions are obtained for the existence of a traveling wave solution connecting the disease-free steady state and the endemic steady state.
文摘This paper deals with the existence of traveling wave solutions in a three-species food-chain model with spatial diffusion and time delays due to gestation and negative feedback. By using a cross iteration scheme and Schauder＇s fixed point theorem, we reduce the existence of traveling wave solutions to the existence of a pair of upper-lower solutions. By constructing a pair of upper-lower solutions, we derive the existence of a traveling wave solution connecting the trivial steady state and the positive steady state. Numerical simulations are carried out to illustrate the main results. In particular, our results extend and improve some known results.
基金This work was supported by the National Natural Science Foundation of China （No. 11071254）.
文摘This paper is concerned with the existence of traveling wave solutions in a reaction- diffusion predator-prey system with nonlocal delays. By introducing a partially expo- nential quasi-monotonicity condition and a new cross iteration scheme, we reduce the existence of traveling wave solutions to the existence of a pair of upper-lower solutions. By constructing a desirable pair of upper-lower solutions, we establish the existence of traveling wave solutions. Finally, some numerical examples are carried out to illustrate the theoretical results.
文摘In this paper, another form of KKM type theorem on generalized convex spaces is obtained and the problems of von Neumann-Fan type sup inf sup inequalities and variational inequalities are discussed for their applications.The main results improve and generalize the corresponding results in previous papers.
基金The second author was supported by the National Key Research and DevelopmentProgram of China (No. 2016YFC0402502)。
文摘This paper is concerned with the minimal wave speed in a diffusive epidemic model with nonlocal delays.We define a threshold.By presenting the existence and the nonexistence of traveling wave solutions for all positive wave speed,we confirm that the threshold is the minimal wave speed of traveling wave solutions,which models that the infective invades the habitat of the susceptible.For some cases,it is proven that spatial nonlocality may increase the propagation threshold while time delay decreases the threshold.
