ASYMPTOTIC EXPANSION AND ASYMPTOTIC BEHAVIOR OF THE SOLUTION FOR THE TIME-DEPENDENT NEUTRON TRANSPORT PROBLEM IN A SLAB WITH GENERALIZED BOUNDARY CONDITIONS

In this paper,the time-dependent neutron transport integro-differential equationin a nonuniform slab with generalized boundary conditions and initial value is considered forgeneral cases concerned with an arbitrary nonhomogeneous medium possibly with cavity,withthe anisotropic scattering and fission,and with continuous energy varying from null to any finiteconstant or from one positive constant to another positive constant.We prove that the correspon-ding neutron transport operator A has finite Spectrum points in any strip {λ|β_1≤R(?)λ≤β_2}whereβ_2>β1>-λ~*(λ~* is the essential infimum of v∑(x,v)),and obtain the asymptotic expansion ofthe time-dependent solution which exists and is unique.Furthermore,we give the existence ofthe dominant eigenvalue and indicate the asymptotic behavior of the neutron density as t→+∞.     

ASYMPTOTIC BEHAVIOR OF THE SOLUTION FOR THE NEUTRON TRANSPORT EQUATION IN A SLAB WITH GENERALIZED REFLECTING BOUNDARY CONDITIONS

This paper discusses the neutron transport equation in a slab with generalized reflectingboundary conditions.By means of the positive C_0-semigroup theory,we have proved that this problemhas a unique nonnegative solution and found the spectral property of the corresponding transportoperator.Finally we give the asymptotic behavior of the solution for this equation.     

CLASSICAL TIME DEPENDENT SOLUTION FORNEUTRON TRANSPORT IN A SLAB WITHGENERALIZED BOUNDARY CONDITIONS

1.IntroductionSincethepioneeringworkofLehner,WingandJorgens['3],thetimedependentneutrontransportproblemhasbeentreatedbymanyinvestigators,andtheliteratureonthissubjectisconsiderable.Variousmethods,theCO-semigroupmethodin[2,3],theNeumannseriesexpansionmetho…     

A NOTE ON THE SPECTRUM OF NEUTRON TRANSPORT OPERATOR IN A SLAB WITH GENERALIZED BOUNDARY CONDITIONS

The spectrum of neutron transport operator A in an arbitrary non-homogeneous slab geometry is discussed in consideration of anisotropic scatteringand fission.Under the assumptions that the boundary reflection coefficient func-tion α(v,μ),γ(v,μ)and the scattering-fission kernel k(x,v,v′,μ,μ′)are boundedmeasurable,and the total collision frequency v∑(x,v)is square integrable,it isshown that A has at most finite spectrum points in any strip{λ=β+i(?)|β_1(?)β(?)β_2},where β_2>β_1>-λ~*,with λ~* the essential infimum of v∑(x,v).Fi-nally,the asymptotic expansion of the solution for the time-dependent equation(dN)/(dt)=AN,N(0)=N_0 is given as a corollary.     

THE RATIONALITY OF THE DISCRETE ORDINATES METHOD FOR TIME DEPENDENT NEUTRON TRANSPORT EQUATION

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THE SOLUTION OF A PARAMETERIC EQUATION ARISING IN TRANSPORT THEORY

This paper deals with the solution of a neutron transport equation with parameter δ.Usingthe theory of functional analysis,we discuss the distribution of the parameters which make the equationhave a non-zero solution,and obtain a necessary and sufficient condition for the existence of thecontrol critical eigenvalue δ_0 which possesses a physical meaning.     

SOLITON AND ELLIPTICAL PERIODIC SOLUTIONS TO THE MODIFIED NONLINEAR SCHRODINGER EQUATION

1.IntroductionAsiswellknown,theNLSE.02 ac Iql:q=0(1)'N Zap Iql:q=0(1)describesthepropagationofpicosecondOPticalpulseinamonomodeOPticalfiber,whereq(',T)istocomplexpulse,'represelltsthedistancealongthedirectionofpropagation,Trepresentsthetimeinthegroupvelocityframeandrs=11.TheNLSEhasbrightsolitonsolutionwhend==1,anddarksolitonsolutionwhena=11.Inthisnotewehaveobtainedthedarksolitonsolutionwhena~1.However,recentworkshaveshownthattheNLSEisnotsufficieDttodescribethepropagationoffemtosecond…     

NONTRIVIAL PERIODIC SOLUTIONS OF A SEMILINEAR WAVE EQUATION WITHOUT ASSUMPTION OF MONOTONICITY

In references,some authors have succeeded in obtaining existence re-sults of the superlinear wave equation without the assumption of monotonicity forthe nonlinear term.In this paper,we present existence results for this problem byusing local linking idea and improve some previous results.     

A PRIOR ESTIMATE AND EXISTENCE OF POSITIVE SOLUTIONS OF SEMILINEAR ELLIPTIC EQUATION WITH THE THIRD BOUNDARY VALUE PROBLEM

1 IntroductionLet n be a bounded open domain with boundary aa, n c R", N 3 2. We consider a priorestimate and ekistence of positive solution of the fOllowing equationsWhere operatorL conforms to the Sum Ru1es, that is: for a repeated i or j, it mean to sum them up from 1 toN, ai;(x), ai(x), a(x) are bounded measurable in a. FOr operator L, we alWays assume: thereealst positive constants po and U1) such thatf(u) is a nonlinear function which grows in the form of Up with p 2 1, n is the out…     

A GENERAL APPROACH BASED ON AUTOCORRELATION TO DETERMINE INPUT VARIABLES OF NEURAL NETWORKS FOR TIME SERIES FORECASTING

Input selection is probably one of the most critical decision issues in neural network designing, because it has a great impact on forecasting performance. Among the many applications of artificial neural networks to finance, time series forecasting is perhaps one of the most challenging issues. Considering the features of neural networks, we propose a general approach called Autocorrelation Criterion (AC) to determine the inputs variables for a neural network. The purpose is to seek optimal lag periods, which are more predictive and less correlated. AC is a data-driven approach in that there is no prior assumption about the models for time series under study. So it has extensive applications and avoids a lengthy experimentation and tinkering in input selection. We apply the approach to the determination of input variables for foreign exchange rate forecasting and conduct comparisons between AC and information-based in-sample model selection criterion. The experiment results show that AC outperforms inf     

QUALITATIVE ANALYSIS FOR A THIRD-ORDER DIFFERENTIAL EQUATION IN A MODEL OF CHEMICAL SYSTEMS

In this paper a mathematical model of chemical systems is investigated.We present the conditions for the existence and local stability of the steady statesand the periodic solution of the Hopf type.Specifically,we show by using an ana-lytical method that there may exist two or four Hopf bifurcation points separatedat a finite distance from each other;at the same time,a technique for studying theHopf bifurcation value is given.     

ASYMPTOTIC NORMALITY OF SOME ESTIMATORS IN A FIXED-DESIGN SEMIPARAMETRIC REGRESSION MODEL WITH LINEAR TIME SERIES ERRORS

Consider a semiparametric regression model with linear time series errors Yk = x'kβ g(tk) εk, 1 < k < n, where Yk's are responses, xk = (xk1,xk2,..... ,xkp)' and tk ∈T ∪R are fixed design points, β= (β1, β2, ....., βp)' is an unknown parameter vector, g(.) is an unknown bounded real-valued function defined on a compact subset T of the real line R, and εk is a linear process given by εk = ∑j=0∞j(?)ek-j,(?)= 1, where , are i.i.d. random variables. In this paper we establish the asymptotic normality of the least squares estimator of β, a smooth estimator of g(.), and estimators of the autocovariance and autocorrelation functions of the linear process εk.     

A LIOUVILLE THEOREM FOR GLOBAL SOLUTIONS OF HOMOGENEOUS CAUCHY PROBLEM OF MRABOLIC EQUATIONS

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A METHOD TO FACTORIZE THE SPECTRAL DENSITY OF MULTIPLE MOVING AVERAGE PROCESSES

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A STACKELBERG DIFFERENTIAL GAMES SOLUTION TO A PROBLEM OF OPTIMAL INTERTEMPORAL INVESTMENT AND TAX RATE DESIGN

Using the Stackelberg differential games(SDG) theory, we quantitatively study a problem of optimal intertemporal investment and tax rate design. Under some appropriate assumptions, the open-loop Stackelberg equilibrium solutions are obtained. Equilibrium solutions show that: 1. The optimal strategies derived from differential game and unilateral optimal control approaches are different; 2. It is not always the best strategy for the government to use a constant tax rate over the whole time period; 3. The admissible size of tax rate adjustment may have great effect on the government's optimal strategy; 4. SDG approach has no significant effect on the firm's optimal investment strategy.     

A NEW PROOF OF THE HADAMARD MONODROMY THEOREM AND THE PERIODIC SOLUTION FOR A CLASS OF O.D.E.SYSTEMS AT RESONANCE

Early in 1904,Hadamard[1]showed the scale implicit function theorem of finitedimensions.Then it was generalized to infinite dimensions.In this paper a new proof of this theoremis given and the unique existence of the periodic solution for a class of ordinary differential equationsystems at resonance is obtained.     

ALMOST PERIODIC SOLUTION FOR A CLASS OF LOTKA-VOLTERRA TYPE N-SPECIES ECOLOGICAL SYSTEMS WITH TIME DELAY

The uniform permanence and global asymptotic stability of a class of almost periodic Lotka-Volterra type N-species competitive systems with diffusion and delays are investigated. It is shown that the system is uniformly persistent under some appropriate conditions, and new sufficient conditions are obtained for the global asymptotic stability of the unique positive almost periodic solution of the system.     

GLOBAL CLASSICAL SOLUTIONS AND EXPLICITEXACT SOLUTIONS TO A KIND OF QUASILINEARPARTIAL DIFFERENTIAL EQUATIONS

1.IntroductionandMainResultTherearemanyexamplesconcerningtheformationofsingularitiesinthesoluti0nsofnon-linearpartialdifferefitialequations.Thus,althoughasolutionmaybesmoothinitially,itmaybecomesingularatsomelatertime(see[1-6]).However,T.Nishidahaspr0vedthatiftheCln0rmoftheinitialdataissufficientlysmall,thentheCauchyproblemadmitsauniqueglobalsmooths0lutionont2Otoareduciblequasilinearhyperbolicsystemwithfirst(lower)orderdissipativeterm(see[7]).Thereafter,manyauthorshavegeneralizedNishida'sr…     

EXISTENCE OF THE VALUE FOR A DIFFERENTIAL GAME WITH SWITCHING STRATEGIES IN A BANACH SPACE

A two-player zero-sum differential game in some Banach space is studied.Positiveswitching costs are associated with each player.By regularizing the game and combining thenotion of viscosity solutions for Isaacs-Bellman equation,we obtain the existence of the Elliot-Kalton value of the game under suitable conditions.