Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting...Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting flood resource variables using single or hybrid machine learning techniques.However,class-based flood predictions have rarely been investigated,which can aid in quickly diagnosing comprehensive flood characteristics and proposing targeted management strategies.This study proposed a prediction approach of flood regime metrics and event classes coupling machine learning algorithms with clustering-deduced membership degrees.Five algorithms were adopted for this exploration.Results showed that the class membership degrees accurately determined event classes with class hit rates up to 100%,compared with the four classes clustered from nine regime metrics.The nonlinear algorithms(Multiple Linear Regression,Random Forest,and least squares-Support Vector Machine)outperformed the linear techniques(Multiple Linear Regression and Stepwise Regression)in predicting flood regime metrics.The proposed approach well predicted flood event classes with average class hit rates of 66.0%-85.4%and 47.2%-76.0%in calibration and validation periods,respectively,particularly for the slow and late flood events.The predictive capability of the proposed prediction approach for flood regime metrics and classes was considerably stronger than that of hydrological modeling approach.展开更多
This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed ...This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations （9 grasslands and 5 forests） were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest （〈600 g C m＇2yrl）. The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest （48.44 Tg C）, and mixed grassland class was the second （16.54 Tg C）, followed by alpine grassland class （3.22 Tg C）, with tundra grassland class being the lowest （0.25 Tg C）. For all the grasslands types, the total NPP of forest meadow was the highest （34.81 Tg C）, followed by sparse forest brush （16.54 Tg C）, and montane meadow was the lowest （0.01 Tg C）.展开更多
Objective: This study seeks to review current and relevant literature on global Angle class III malocclusion prevalence. Materials and Methods: The electronic databases PubMed, ISI Web of Knowledge, and the Cochrane D...Objective: This study seeks to review current and relevant literature on global Angle class III malocclusion prevalence. Materials and Methods: The electronic databases PubMed, ISI Web of Knowledge, and the Cochrane Database of Systematic Review were searched using specific inclusion criteria to obtain applicable articles. All pertinent references were also examined for acceptability. Results: A total of 20 articles were identified using the inclusion criteria. The prevalence of Angle class III malocclusion ranged from 0 to 26.7% in different populations reported in the literature examined. Meta-regression analysis showed no statistically significant association between prevalence rates and the method of assessment, age group and year of the study. However, much of the study-to-study variation (approximately 40%) could be explained by population. Conclusion: These results suggest that the prevalence of Angle class III malocclusion varies greatly within different races and geographic regions. Chinese and Malaysian populations have a higher prevalence of Angle class III malocclusion compared to other racial groups, while Indian populations have a lower prevalence than all other racial groups examined.展开更多
In this note,the explicit form of the N soliton solutions for a class of the system of LS nonlinear wave interaction have been obtained by using Hirota's method.
A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classe...A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classes, and fuzzy approximations are defined based on them. Three types of relative reducts of maximal tolerance classes are then proposed, and three types of fuzzy decision rules based on the proposed attribute description are defined. The judgment theorems and approximation discernibility functions with respect to them are presented to compute the relative reduct by using Boolean reasoning techniques, from which we can derive optimal fuzzy decision rules from the systems. At last, three types of relative reducts of the system and their computing methods are given.展开更多
The nonlinear interactions between the monochromatic wave have been considered by K. Matsunchi, who also proposed one class of the nonlinear Schrdinger equation system with wave operator. We also obtain the same type ...The nonlinear interactions between the monochromatic wave have been considered by K. Matsunchi, who also proposed one class of the nonlinear Schrdinger equation system with wave operator. We also obtain the same type of equations, which are satisfied by transverse velocity of higher frequency electron, as we study soliton in plasma physics. In this paper, under some condition we study the existence and nonexistence for this equations in the cases possessing different signs in nonlinear term.展开更多
As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow tre...As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow trees for wood production as an economic activity.The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil.Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density.Three trees each of a species from the pioneer,early and late secondary successional stages and of the dominant species in the climax community.The radial profiles indicated increasing density from the pith to bark of trunks,except for some variations due to wood defects and growth.Average density was 0.576 g cm^(-3),0.655 g cm^(-3),0.706 g cm^(-3)and 0.775 g cm^(-3),respectively,for Peltophorum dubium,Schinus terebinthifolius,Cariniana estrellensis and Hymenaea courbaril.Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species.X-ray densitometry generated parameters such as minimum,average and maximum densities,and radial density variations.These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.展开更多
In this paper, we discuss the limit cycles of the systemdx/dt=y·[1+(A(x)]oy/dt=(-x+δy+α_1x^2+α_2xy+α_5x^2y)[1+B(x)] (1)where A(x)=sum form i=1 to n(a_ix~), B(x)=sum form j=1 to m(β_jx^j) and 1+B(x)>0. We ...In this paper, we discuss the limit cycles of the systemdx/dt=y·[1+(A(x)]oy/dt=(-x+δy+α_1x^2+α_2xy+α_5x^2y)[1+B(x)] (1)where A(x)=sum form i=1 to n(a_ix~), B(x)=sum form j=1 to m(β_jx^j) and 1+B(x)>0. We prove that (1) possesses at most one limit cycle and give out the necessary and sufficient conditions of existence and uniqueness of limit cycles.展开更多
The exact solutions for stationary responses of one class of the second order and three classes of higher order nonlinear systems to parametric and/or external while noise excitations are constructed by using Fokkcr-P...The exact solutions for stationary responses of one class of the second order and three classes of higher order nonlinear systems to parametric and/or external while noise excitations are constructed by using Fokkcr-Planck-Kolmogorov et/ualion approach. The conditions for the existence and uniqueness and the behavior of the solutions are discussed. All the systems under consideration are characterized by the dependence ofnonconservative fqrces on the first integrals of the corresponding conservative systems and arc catted generalized-energy-dependent f G.E.D.) systems. It is shown taht for each of the four classes of G.E.D. nonlinear stochastic systems there is a family of non-G.E.D. systems which are equivalent to the G.E.D. system in the sense of having identical stationary solution. The way to find the equivalent stochastic systems for a given G.E.D. system is indicated and. as an example, the equivalent stochastic systems for the second order G.E. D. nonlinear stochastic system are given. It is pointed out and illustrated with example that the exact stationary solutions for many non-G.E.D. nonlinear stochastic systems may he found by searching the equivalent G.E.D. systems.展开更多
Let D be N+1 connected bounded domain in plane. Suppose the contour of D consists of N+1 simple-ly closed curves <sub>0</sub>, <sub>1</sub>…, <sub>N</sub> and <sub>1</s...Let D be N+1 connected bounded domain in plane. Suppose the contour of D consists of N+1 simple-ly closed curves <sub>0</sub>, <sub>1</sub>…, <sub>N</sub> and <sub>1</sub>… <sub>N</sub> are in the interior of domain circumscribed byC<sub>μ</sub><sup>1</sup>（0 【μ【 1）. In addition, assume that there are n mutually exclusive contour γ<sub>,</sub>j=1,…,n,in interi-or of D,γ=γ<sub>i</sub>; ∈C<sub>μ</sub><sup>1</sup>. Denote D<sub>j</sub> is the bounded domain circumscribed by γ<sub>j</sub>,j=1,…,n, D<sup>-</sup>=D<sub>1</sub>+…+D.,D<sup>+</sup>=D-D<sup>-</sup>,D<sub>t</sub><sup> </sup>=D<sup> </sup>×E, E=[0,T] （T】0）, z=0∈D<sup>+</sup>.We consider the following pseudoparabolic complex equation on D<sub>t</sub><sup> </sup> : / t[W<sub>Z</sub>- Q<sub>1</sub>（z）W<sub>z</sub>- Q<sub>2</sub>（z） <sub> </sub>- A<sub>1</sub>（z）W - A<sub>2</sub>（Z） ]= H（t,z,W,W-<sub>2</sub>,W<sub>2</sub>）, （z,t） ∈D<sub>t</sub><sup> </sup>, （1）展开更多
In this paper, we will discuss a class of integro-differential system of equations. It is a mathematicalmodel which is drown from the practical problems of the population control system with illness:where 0 【r<sup...In this paper, we will discuss a class of integro-differential system of equations. It is a mathematicalmodel which is drown from the practical problems of the population control system with illness:where 0 【r<sup>’</sup> m【r<sub>m</sub> and r<sub>m</sub> is the highest age over attained by individual of the population. In this pa-per, P<sub>1</sub>= P<sub>1</sub>（x,t） denotes the age density function of the healthy population; P<sub>2</sub> = P<sub>2</sub>（r,s,ts） denotes theage and period of illness density function of the morbid population; λ（r） =λ（r,t） denotes the relative inci-dence of diseases; η（r,s） =η（r.s.t）denotes the relative recovering rate of patients;μ<sub>2</sub>（r,s） = μ2（r,s,t）denotes the relative mortality of patients. And the other functions μ<sub>1</sub>,（r） =μ<sub>1</sub>,（r,t）, β=β（t） , h（r）展开更多
In this paper, the periodic boundary problem and the initial value problem for the nonlinear system of parabolic type u1=-A（x, t）ux4+B（x, t）ux2+（g（u））x2+（grad h（u））x+f（u）are studied, where u（x, t）=(u1...In this paper, the periodic boundary problem and the initial value problem for the nonlinear system of parabolic type u1=-A（x, t）ux4+B（x, t）ux2+（g（u））x2+（grad h（u））x+f（u）are studied, where u（x, t）=(u1（x, t）.…, uJ（x, t） is a J-dimensional unknown vector valued function, f（u） and g（u） are the J-dimensional vector valued function of u（x, t）, h（u） is a scalar function of u, A（x, t） and B（x, t） are J×J matrices of functions. The existent, uniqueness and regularities of the generalized global solution and classical global solution of the problems are proved. When J=1, h（u）=0, g（u）=au3, A=a1, B=a2, where a1, a2 a are constants, the system is a generalized diffusion model equation in population problem.展开更多
A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and t...A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and the unreal time message served with gated service discipline. Using an iterative method, the exact mean waiting times for both message classes are derived. The influence of the gate location of the message class served by the gated service discipline on the mean waiting time is also analyzed. The analytical results are verified with simulation method and agree well with simulation results.展开更多
We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ES...We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ESD） is a general phenomenon and it usually takes place in a qubit-qutrit system interacting with various noisy channels, not only the ease with dephasing and depolarizing channels observed by others. ESD can only be avoided for some initially entangled states under some particular noisy channels. Moreover, the environment affects the entanglement and the coherence of the system in very different ways.展开更多
The acceptance gap micro control system applies to the entrance ramp in which the prior consideration is given to the merging safety. Based on the actual condition of interchanges and the vehicle composition in our c...The acceptance gap micro control system applies to the entrance ramp in which the prior consideration is given to the merging safety. Based on the actual condition of interchanges and the vehicle composition in our country, the traffic characteristics for high class roadways are analyzed and the system simulation model is developed. A simulation example is also given in the paper. Through the simulation, the optimal ramp control plan can be obtained.展开更多
Information systems and information technology (IS/IT) play an important role in supporting the organization to conduct its business processes. The research was conducted at the University of Satya Christian Wacana (S...Information systems and information technology (IS/IT) play an important role in supporting the organization to conduct its business processes. The research was conducted at the University of Satya Christian Wacana (SWCU). Business processes in perceived walking SWCU are not optimal in using IS/IT in the organization. The planning process/IT has not been done in all business units and SWCU does not have an Executive Information System that can help in the decision making process. The process of strategic planning of information systems and information technology using The Open Group Architecture Framework (TOGAF) has compiled a few methods of strategic planning. The results obtained by the study of the needs of IS/IT in SWCU generating application portfolio will be implemented in the institution.展开更多
Gyllenberg and Yan(Discrete Contin Dyn Syst Ser B 11(2):347–352,2009)presented a system in Zeeman’s class 30 of 3-dimensional Lotka-Volterra(3D LV)competitive systems to admit at least two limit cycles,one of which ...Gyllenberg and Yan(Discrete Contin Dyn Syst Ser B 11(2):347–352,2009)presented a system in Zeeman’s class 30 of 3-dimensional Lotka-Volterra(3D LV)competitive systems to admit at least two limit cycles,one of which is generated by the Hopf bifurcation and the other is obtained by the Poincaré-Bendixson theorem.Yu et al.(J Math Anal Appl 436:521–555,2016,Sect.3.4)recalculated the first Liapunov coefficient of Gyllenberg and Yan’s system to be positive,rather than negative as in Gyllenberg and Yan(2009),and pointed out that the Poincaré-Bendixson theorem is not applicable for that system.Jiang et al.(J Differ Equ 284:183–218,2021,p.213)proposed an open question:“whether Zeeman’s class 30 can be rigorously proved to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem?”This paper provides four systems in Zeeman’s class 30 to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem and gives an answer to the above question.展开更多
基金National Key Research and Development Program of China,No.2023YFC3006704National Natural Science Foundation of China,No.42171047CAS-CSIRO Partnership Joint Project of 2024,No.177GJHZ2023097MI。
文摘Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting flood resource variables using single or hybrid machine learning techniques.However,class-based flood predictions have rarely been investigated,which can aid in quickly diagnosing comprehensive flood characteristics and proposing targeted management strategies.This study proposed a prediction approach of flood regime metrics and event classes coupling machine learning algorithms with clustering-deduced membership degrees.Five algorithms were adopted for this exploration.Results showed that the class membership degrees accurately determined event classes with class hit rates up to 100%,compared with the four classes clustered from nine regime metrics.The nonlinear algorithms(Multiple Linear Regression,Random Forest,and least squares-Support Vector Machine)outperformed the linear techniques(Multiple Linear Regression and Stepwise Regression)in predicting flood regime metrics.The proposed approach well predicted flood event classes with average class hit rates of 66.0%-85.4%and 47.2%-76.0%in calibration and validation periods,respectively,particularly for the slow and late flood events.The predictive capability of the proposed prediction approach for flood regime metrics and classes was considerably stronger than that of hydrological modeling approach.
基金the National Basic Research Program of China(2010CB950702)the National High-Technology Reaearch and Development Program of China(2007AA10Z231)the Asia-Pacific Network for Global Change Research Project(ARCP201106CMY-Li)
文摘This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations （9 grasslands and 5 forests） were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest （〈600 g C m＇2yrl）. The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest （48.44 Tg C）, and mixed grassland class was the second （16.54 Tg C）, followed by alpine grassland class （3.22 Tg C）, with tundra grassland class being the lowest （0.25 Tg C）. For all the grasslands types, the total NPP of forest meadow was the highest （34.81 Tg C）, followed by sparse forest brush （16.54 Tg C）, and montane meadow was the lowest （0.01 Tg C）.
文摘Objective: This study seeks to review current and relevant literature on global Angle class III malocclusion prevalence. Materials and Methods: The electronic databases PubMed, ISI Web of Knowledge, and the Cochrane Database of Systematic Review were searched using specific inclusion criteria to obtain applicable articles. All pertinent references were also examined for acceptability. Results: A total of 20 articles were identified using the inclusion criteria. The prevalence of Angle class III malocclusion ranged from 0 to 26.7% in different populations reported in the literature examined. Meta-regression analysis showed no statistically significant association between prevalence rates and the method of assessment, age group and year of the study. However, much of the study-to-study variation (approximately 40%) could be explained by population. Conclusion: These results suggest that the prevalence of Angle class III malocclusion varies greatly within different races and geographic regions. Chinese and Malaysian populations have a higher prevalence of Angle class III malocclusion compared to other racial groups, while Indian populations have a lower prevalence than all other racial groups examined.
基金Project supported by the National Natural Science Foundation of China.
文摘In this note,the explicit form of the N soliton solutions for a class of the system of LS nonlinear wave interaction have been obtained by using Hirota's method.
基金supported by the National Natural Science Foundation of China (61070241)the Natural Science Foundation of Shandong Province (ZR2010FM035)Science Research Foundation of University of Jinan (XKY0808)
文摘A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classes, and fuzzy approximations are defined based on them. Three types of relative reducts of maximal tolerance classes are then proposed, and three types of fuzzy decision rules based on the proposed attribute description are defined. The judgment theorems and approximation discernibility functions with respect to them are presented to compute the relative reduct by using Boolean reasoning techniques, from which we can derive optimal fuzzy decision rules from the systems. At last, three types of relative reducts of the system and their computing methods are given.
文摘The nonlinear interactions between the monochromatic wave have been considered by K. Matsunchi, who also proposed one class of the nonlinear Schrdinger equation system with wave operator. We also obtain the same type of equations, which are satisfied by transverse velocity of higher frequency electron, as we study soliton in plasma physics. In this paper, under some condition we study the existence and nonexistence for this equations in the cases possessing different signs in nonlinear term.
基金This study is funded by the Coordination for the Improvement of Higher Education Personnel(CAPES).
文摘As forests in neotropical regions,particularly in developing countries,are devastated,interventions to restore biodiversity and its ecological functions are needed.Rural producers have thus been encouraged to grow trees for wood production as an economic activity.The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil.Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density.Three trees each of a species from the pioneer,early and late secondary successional stages and of the dominant species in the climax community.The radial profiles indicated increasing density from the pith to bark of trunks,except for some variations due to wood defects and growth.Average density was 0.576 g cm^(-3),0.655 g cm^(-3),0.706 g cm^(-3)and 0.775 g cm^(-3),respectively,for Peltophorum dubium,Schinus terebinthifolius,Cariniana estrellensis and Hymenaea courbaril.Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species.X-ray densitometry generated parameters such as minimum,average and maximum densities,and radial density variations.These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.
文摘In this paper, we discuss the limit cycles of the systemdx/dt=y·[1+(A(x)]oy/dt=(-x+δy+α_1x^2+α_2xy+α_5x^2y)[1+B(x)] (1)where A(x)=sum form i=1 to n(a_ix~), B(x)=sum form j=1 to m(β_jx^j) and 1+B(x)>0. We prove that (1) possesses at most one limit cycle and give out the necessary and sufficient conditions of existence and uniqueness of limit cycles.
基金Project Supported by The National Natural Science Foundation of China
文摘The exact solutions for stationary responses of one class of the second order and three classes of higher order nonlinear systems to parametric and/or external while noise excitations are constructed by using Fokkcr-Planck-Kolmogorov et/ualion approach. The conditions for the existence and uniqueness and the behavior of the solutions are discussed. All the systems under consideration are characterized by the dependence ofnonconservative fqrces on the first integrals of the corresponding conservative systems and arc catted generalized-energy-dependent f G.E.D.) systems. It is shown taht for each of the four classes of G.E.D. nonlinear stochastic systems there is a family of non-G.E.D. systems which are equivalent to the G.E.D. system in the sense of having identical stationary solution. The way to find the equivalent stochastic systems for a given G.E.D. system is indicated and. as an example, the equivalent stochastic systems for the second order G.E. D. nonlinear stochastic system are given. It is pointed out and illustrated with example that the exact stationary solutions for many non-G.E.D. nonlinear stochastic systems may he found by searching the equivalent G.E.D. systems.
文摘Let D be N+1 connected bounded domain in plane. Suppose the contour of D consists of N+1 simple-ly closed curves <sub>0</sub>, <sub>1</sub>…, <sub>N</sub> and <sub>1</sub>… <sub>N</sub> are in the interior of domain circumscribed byC<sub>μ</sub><sup>1</sup>（0 【μ【 1）. In addition, assume that there are n mutually exclusive contour γ<sub>,</sub>j=1,…,n,in interi-or of D,γ=γ<sub>i</sub>; ∈C<sub>μ</sub><sup>1</sup>. Denote D<sub>j</sub> is the bounded domain circumscribed by γ<sub>j</sub>,j=1,…,n, D<sup>-</sup>=D<sub>1</sub>+…+D.,D<sup>+</sup>=D-D<sup>-</sup>,D<sub>t</sub><sup> </sup>=D<sup> </sup>×E, E=[0,T] （T】0）, z=0∈D<sup>+</sup>.We consider the following pseudoparabolic complex equation on D<sub>t</sub><sup> </sup> : / t[W<sub>Z</sub>- Q<sub>1</sub>（z）W<sub>z</sub>- Q<sub>2</sub>（z） <sub> </sub>- A<sub>1</sub>（z）W - A<sub>2</sub>（Z） ]= H（t,z,W,W-<sub>2</sub>,W<sub>2</sub>）, （z,t） ∈D<sub>t</sub><sup> </sup>, （1）
基金The project is supported by the National Natural Science Foundation of P.R.China
文摘In this paper, we will discuss a class of integro-differential system of equations. It is a mathematicalmodel which is drown from the practical problems of the population control system with illness:where 0 【r<sup>’</sup> m【r<sub>m</sub> and r<sub>m</sub> is the highest age over attained by individual of the population. In this pa-per, P<sub>1</sub>= P<sub>1</sub>（x,t） denotes the age density function of the healthy population; P<sub>2</sub> = P<sub>2</sub>（r,s,ts） denotes theage and period of illness density function of the morbid population; λ（r） =λ（r,t） denotes the relative inci-dence of diseases; η（r,s） =η（r.s.t）denotes the relative recovering rate of patients;μ<sub>2</sub>（r,s） = μ2（r,s,t）denotes the relative mortality of patients. And the other functions μ<sub>1</sub>,（r） =μ<sub>1</sub>,（r,t）, β=β（t） , h（r）
文摘In this paper, the periodic boundary problem and the initial value problem for the nonlinear system of parabolic type u1=-A（x, t）ux4+B（x, t）ux2+（g（u））x2+（grad h（u））x+f（u）are studied, where u（x, t）=(u1（x, t）.…, uJ（x, t） is a J-dimensional unknown vector valued function, f（u） and g（u） are the J-dimensional vector valued function of u（x, t）, h（u） is a scalar function of u, A（x, t） and B（x, t） are J×J matrices of functions. The existent, uniqueness and regularities of the generalized global solution and classical global solution of the problems are proved. When J=1, h（u）=0, g（u）=au3, A=a1, B=a2, where a1, a2 a are constants, the system is a generalized diffusion model equation in population problem.
基金Sponsored by the National Natural Science Foundation of China (No .60474031) the National"863"Program Project (2002AA412010-08)
文摘A novel mixed polling system with multiple stations is considered. Each station produces two classes of messages served with different disciplines. The real time message served with exhaustive service discipline and the unreal time message served with gated service discipline. Using an iterative method, the exact mean waiting times for both message classes are derived. The influence of the gate location of the message class served by the gated service discipline on the mean waiting time is also analyzed. The analytical results are verified with simulation method and agree well with simulation results.
基金Funded by the National Natural Science Foundation of China(Grant No.50375071) ,the National Natural Science Foundation of Jiangsu Province Education Department ( Grant No. 2004JD028J) and the Science Foundation of Zhenjiang City( Grant No.2004JD020J)
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10974020 and 11174039,NCET-11-0031the Fundamental Research Funds for the Central Universities
文摘We investigate the dynamics of entanglement for a two-parameter class of states in a hybrid qubit-qutrit system under the influence of various dissipative channels. Our results show that entanglement sudden death （ESD） is a general phenomenon and it usually takes place in a qubit-qutrit system interacting with various noisy channels, not only the ease with dephasing and depolarizing channels observed by others. ESD can only be avoided for some initially entangled states under some particular noisy channels. Moreover, the environment affects the entanglement and the coherence of the system in very different ways.
文摘The acceptance gap micro control system applies to the entrance ramp in which the prior consideration is given to the merging safety. Based on the actual condition of interchanges and the vehicle composition in our country, the traffic characteristics for high class roadways are analyzed and the system simulation model is developed. A simulation example is also given in the paper. Through the simulation, the optimal ramp control plan can be obtained.
文摘Information systems and information technology (IS/IT) play an important role in supporting the organization to conduct its business processes. The research was conducted at the University of Satya Christian Wacana (SWCU). Business processes in perceived walking SWCU are not optimal in using IS/IT in the organization. The planning process/IT has not been done in all business units and SWCU does not have an Executive Information System that can help in the decision making process. The process of strategic planning of information systems and information technology using The Open Group Architecture Framework (TOGAF) has compiled a few methods of strategic planning. The results obtained by the study of the needs of IS/IT in SWCU generating application portfolio will be implemented in the institution.
基金the National Natural Science Foundation of China(NSFC)under Grant No.12171321.
文摘Gyllenberg and Yan(Discrete Contin Dyn Syst Ser B 11(2):347–352,2009)presented a system in Zeeman’s class 30 of 3-dimensional Lotka-Volterra(3D LV)competitive systems to admit at least two limit cycles,one of which is generated by the Hopf bifurcation and the other is obtained by the Poincaré-Bendixson theorem.Yu et al.(J Math Anal Appl 436:521–555,2016,Sect.3.4)recalculated the first Liapunov coefficient of Gyllenberg and Yan’s system to be positive,rather than negative as in Gyllenberg and Yan(2009),and pointed out that the Poincaré-Bendixson theorem is not applicable for that system.Jiang et al.(J Differ Equ 284:183–218,2021,p.213)proposed an open question:“whether Zeeman’s class 30 can be rigorously proved to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem?”This paper provides four systems in Zeeman’s class 30 to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem and gives an answer to the above question.
