Let Fpm be a finite field with pm elements,where p is an odd prime and m is a positive integer.Recently,[17]and[35]determined the weight distributions of subfield codes with the form C f={((T r(a f(x)+b x)+c)...Let Fpm be a finite field with pm elements,where p is an odd prime and m is a positive integer.Recently,[17]and[35]determined the weight distributions of subfield codes with the form C f={((T r(a f(x)+b x)+c)_(x∈Fpm),T r(a)):a,b∈Fpm,c∈Fp}for f(x)=x2 and f(x)=x p k+1,respectively,where Tr(⋅)is the trace function from Fpm to Fp,and k is a nonnegative integer.In this paper,we further investigate the subfield code C f for f(x)being a known perfect nonlinear function over Fpm and generalize some results in[17,35].The weight distributions of the constructed codes are determined by applying the theory of quadratic forms and the properties of perfect nonlinear functions over finite fields.In addition,the parameters of the duals of these codes are also determined.Several examples show that some of our codes and their duals have the best known parameters according to the code tables in[16].The duals of some proposed codes are optimal according to the Sphere Packing bound if p≥5.展开更多
The existence and representation of the exact solution are given for a nonlinear functional equation in the reproducing kernel space. For a numerical computation, we present a large-range convergence iterative method ...The existence and representation of the exact solution are given for a nonlinear functional equation in the reproducing kernel space. For a numerical computation, we present a large-range convergence iterative method for solving the nonlinear functional equation. In the iterative method, the convergent condition is simple and the convergence is irrespective to the choice of the initial function. It is worthy to note that the presented method can be generalized to solve other nonlinear operator equations.展开更多
The main objective of this article is to study the oscillatory behavior of the solutions of the following nonlinear functional differential equations(a(t)x'(t))'+δ1p(t)x'(t) +δ2q(t)f(x(g(t))) ...The main objective of this article is to study the oscillatory behavior of the solutions of the following nonlinear functional differential equations(a(t)x'(t))'+δ1p(t)x'(t) +δ2q(t)f(x(g(t))) = 0,for 0 ≤ to≤ t, where 51 = :El and δ±1. The functions p,q,g : [t0, ∞) → R, f : R → are continuous, a(t) 〉 0,p(t) ≥0,q(t) 〉 0 for t ≥ to,lirn g(t) = ∞, and q is not identically zero on any subinterval of [to, ∞). Moreover, the functions q(t), g(t), and a(t) are continuously differentiable.展开更多
Nonlinear computation is essential for a wide range of information processing tasks,yet implementing nonlinear functions using optical systems remains a challenge due to the weak and power-intensive nature of optical ...Nonlinear computation is essential for a wide range of information processing tasks,yet implementing nonlinear functions using optical systems remains a challenge due to the weak and power-intensive nature of optical nonlinearities.Overcoming this limitation without relying on nonlinear optical materials could unlock unprecedented opportunities for ultrafast and parallel optical computing systems.Here,we demonstrate that large-scale nonlinear computation can be performed using linear optics through optimized diffractive processors composed of passive phase-only surfaces.In this framework,the input variables of nonlinear functions are encoded into the phase of an optical wavefront—e.g.,via a spatial light modulator(SLM)—and transformed by an optimized diffractive structure with spatially varying point-spread functions to yield output intensities that approximate a large set of unique nonlinear functions–all in parallel.We provide proof establishing that this architecture serves as a universal function approximator for an arbitrary set of bandlimited nonlinear functions,also covering wavelength-multiplexed nonlinear functions as well as multi-variate and complex-valued functions that are all-optically cascadable.Our analysis also indicates the successful approximation of typical nonlinear activation functions commonly used in neural networks,including the sigmoid,tanh,ReLU(rectified linear unit),and softplus.We numerically demonstrate the parallel computation of one million distinct nonlinear functions,accurately executed at wavelength-scale spatial density at the output of a diffractive optical processor.Furthermore,we experimentally validated this framework using in situ optical learning and approximated 35 unique nonlinear functions in a single shot using a compact setup consisting of an SLM and an image sensor.These results establish diffractive optical processors as a scalable platform for massively parallel universal nonlinear function approximation,paving the way for new capabilities in analog optical computing based on linear materials.展开更多
In normed linear spaces,by applying the Minkowski difference,the concepts of efficient solutions,weakly efficient solutions,proper efficient solutions and Henig efficient solutions are introduced for set optimization ...In normed linear spaces,by applying the Minkowski difference,the concepts of efficient solutions,weakly efficient solutions,proper efficient solutions and Henig efficient solutions are introduced for set optimization with respect to co-radiant sets,and the relationships among them is discussed.Optimality conditions for minimal solutions and strictly minimal solutions of scalar set optimization are established by using the generalized oriented distance functions,respectively.The relationship between the solutions of set optimization problem and the solutions of scalar problem is studied.Several examples are given to explain our result.Properties of Gerstewitz’s functions with respect to co-radiant sets are discussed,which are used to establish sufficient conditions for weakly efficient solutions of set optimization.展开更多
A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented,which provides a kind of unified constructions of constant-composition codes based on all...A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented,which provides a kind of unified constructions of constant-composition codes based on all known perfect nonlinear functions from F qm to itself.It is proved that the new constant-composition codes are optimal with respect to the Luo-Fu-Vinck-Chen bound,when m is an odd positive integer greater than 1.Finally,we point out that two constructions of constant-composition codes,proposed by Ding Cunsheng et al.in 2005,are equivalent to two special types of the new constant-composition codes.展开更多
Dear Editor,This letter investigates the fuzzy prescribed-time control(PTC)problem for a class of uncertain pure feedback nonlinear systems.Firstly,a novel prescribed-time stability lemma is introduced,which plays a c...Dear Editor,This letter investigates the fuzzy prescribed-time control(PTC)problem for a class of uncertain pure feedback nonlinear systems.Firstly,a novel prescribed-time stability lemma is introduced,which plays a critical role in stability analysis.Unlike existing PTC algorithms,where the nonlinear functions are typically known or satisfy a linear growth condition,our approach does not require such assumptions.To address these unknown factors,fuzzy logic systems(FLSs)are employed.Based on the new prescribed-time stability lemma,it is proven that the controller and all system states converge to the origin within the prescribed time and remain there.Finally,the effectiveness of the proposed algorithm is validated through a simulation example.展开更多
In order to improve the harsh dynamic environment experienced by heavy rockets during different external excitations,this study presents a novel active variable stiffness vibration isolator(AVS-VI)used as the vibratio...In order to improve the harsh dynamic environment experienced by heavy rockets during different external excitations,this study presents a novel active variable stiffness vibration isolator(AVS-VI)used as the vibration isolation device to reduce excessive vibration of the whole-spacecraft isolation system.The AVS-VI is composed of horizontal stiffness spring,positive stiffness spring,parallelogram linkage mechanism,piezoelectric actuator,acceleration sensor,viscoelastic damping,and PID active controller.Based on the AVS-VI,the generalized vibration transmissibility determined by the nonlinear output frequency response functions and the energy absorption rate is applied to analyze the isolation performance of the whole-spacecraft system with AVS-VI.The AVS-VI can conduct adaptive vibration suppression with variable stiffness to the whole-spacecraft system,and the analysis results indicate that the AVS-VI is efTective in reducing the extravagant vibration of the whole-spacecraft system,where the vibration isolation is decreased up to above 65%under different acceleration excitations.Finally,different parameters of AVS-VI are considered to optimize the whole-spacecraft system based on the generalized vibration transmissibility and the energy absorption rate.展开更多
The nonlinear Wannier functions in square Kronig-Penney potential are investigated with the help of a set of exact nonlinear Bloch solutions. The nonlinear interaction makes the Wannier functions fall off as non-expon...The nonlinear Wannier functions in square Kronig-Penney potential are investigated with the help of a set of exact nonlinear Bloch solutions. The nonlinear interaction makes the Wannier functions fall off as non-exponential law with distance and enhances the tunneling coupling between the neighbor sites.展开更多
The penalty function method, presented many years ago, is an important nu- merical method for the mathematical programming problems. In this article, we propose a dual-relax penalty function approach, which is signifi...The penalty function method, presented many years ago, is an important nu- merical method for the mathematical programming problems. In this article, we propose a dual-relax penalty function approach, which is significantly different from penalty func- tion approach existing for solving the bilevel programming, to solve the nonlinear bilevel programming with linear lower level problem. Our algorithm will redound to the error analysis for computing an approximate solution to the bilevel programming. The error estimate is obtained among the optimal objective function value of the dual-relax penalty problem and of the original bilevel programming problem. An example is illustrated to show the feasibility of the proposed approach.展开更多
In this paper, we consider a general nonlinear integral operator Hαi, βi ( f1,..., fn ; g1,..., gn)(z). Some results including coefficient problems, univalency condition and radius of convexity for this integral...In this paper, we consider a general nonlinear integral operator Hαi, βi ( f1,..., fn ; g1,..., gn)(z). Some results including coefficient problems, univalency condition and radius of convexity for this integral operator are given. Furthermore, we discuss the mapping properties between Hαi,βi (f1 , fn, ; g1,..., gn)(z) and subclasses of analytic functions with bounded boundary rotation. The same subjects for some corresponding classes are shown upon specializing the parameters in our main results.展开更多
In this paper an orthogonal function method is presented based on the idea to suppose perioche sohuion with the method of harmonie balance The displaeement is expressed in the form of trigonometric fumctions a group o...In this paper an orthogonal function method is presented based on the idea to suppose perioche sohuion with the method of harmonie balance The displaeement is expressed in the form of trigonometric fumctions a group of simplified digenequationsare obtained by the use of orthogonarity of trigonometric fumetions and linear mondes The method overcomes the diffieulty of a drifi term existing in systems with quadratic nonlinearities .The ealeulation examples show that the method has thd advantages of high caleulation preeision high convergenee speed and littld ealeulation work展开更多
The joint probability density fimction (PDF) of different structural responses is a very important topic in the stochastic response analysis of nonlinear structures. In this paper, the probability density evolution ...The joint probability density fimction (PDF) of different structural responses is a very important topic in the stochastic response analysis of nonlinear structures. In this paper, the probability density evolution method, which is successfully developed to capture the instantaneous PDF of an arbitrary single response of interest, is extended to evaluate the joint PDF of any two responses. A two-dimensional partial differential equation in terms of the joint PDF is established. The strategy of selecting representative points via the number theoretical method and sieved by a hyper-ellipsoid is outlined. A two-dimensional difference scheme is developed. The free vibration of an SDOF system is examined to verify the proposed method, and a flame structure exhibiting hysteresis subjected to stochastic ground motion is investigated. It is pointed out that the correlation of different responses results from the fact that randomness of different responses comes from the same set of basic random parameters involved. In other words, the essence of the probabilistic correlation is a physical correlation.展开更多
We explore the theoretical possibility of extending the usual squeezed state to those produced by nonlinear singlemode squeezing operators. We derive the wave functions of exp[-(ig/2)((1-X2)1/2P + P(1-X2)1/2)...We explore the theoretical possibility of extending the usual squeezed state to those produced by nonlinear singlemode squeezing operators. We derive the wave functions of exp[-(ig/2)((1-X2)1/2P + P(1-X2)1/2)]|0 in the coordinate representation. A new operator's disentangling formula is derived as a by-product.展开更多
A mechanism for proving global convergence in filter-SQP (sequence of quadratic programming) method with the nonlinear complementarity problem (NCP) function is described for constrained nonlinear optimization pro...A mechanism for proving global convergence in filter-SQP (sequence of quadratic programming) method with the nonlinear complementarity problem (NCP) function is described for constrained nonlinear optimization problem.We introduce an NCP function into the filter and construct a new SQP-filter algorithm.Such methods are characterized by their use of the dominance concept of multi-objective optimization,instead of a penalty parameter whose adjustment can be problematic.We prove that the algorithm has global convergence and superlinear convergence rates under some mild conditions.展开更多
An exact augmented Lagrangian function for the nonlinear nonconvex programming problems with inequality constraints was discussed. Under suitable hypotheses, the relationship was established between the local unconstr...An exact augmented Lagrangian function for the nonlinear nonconvex programming problems with inequality constraints was discussed. Under suitable hypotheses, the relationship was established between the local unconstrained minimizers of the augmented Lagrangian function on the space of problem variables and the local minimizers of the original constrained problem. Furthermore, under some assumptions, the relationship was also established between the global solutions of the augmented Lagrangian function on some compact subset of the space of problem variables and the global solutions of the constrained problem. Therefore, f^om the theoretical point of view, a solution of the inequality constrained problem and the corresponding values of the Lagrange multipliers can be found by the well-known method of multipliers which resort to the unconstrained minimization of the augmented Lagrangian function presented.展开更多
Tool condition monitoring(TCM)is a key technology for intelligent manufacturing.The objective is to monitor the tool operation status and detect tool breakage so that the tool can be changed in time to avoid significa...Tool condition monitoring(TCM)is a key technology for intelligent manufacturing.The objective is to monitor the tool operation status and detect tool breakage so that the tool can be changed in time to avoid significant damage to workpieces and reduce manufacturing costs.Recently,an innovative TCM approach based on sensor data modelling and model frequency analysis has been proposed.Different from traditional signal feature-based monitoring,the data from sensors are utilized to build a dynamic process model.Then,the nonlinear output frequency response functions,a concept which extends the linear system frequency response function to the nonlinear case,over the frequency range of the tooth passing frequency of the machining process are extracted to reveal tool health conditions.In order to extend the novel sensor data modelling and model frequency analysis to unsupervised condition monitoring of cutting tools,in the present study,a multivariate control chart is proposed for TCM based on the frequency domain properties of machining processes derived from the innovative sensor data modelling and model frequency analysis.The feature dimension is reduced by principal component analysis first.Then the moving average strategy is exploited to generate monitoring variables and overcome the effects of noises.The milling experiments of titanium alloys are conducted to verify the effectiveness of the proposed approach in detecting excessive flank wear of solid carbide end mills.The results demonstrate the advantages of the new approach over conventional TCM techniques and its potential in industrial applications.展开更多
The unicity of the solution, if any, of a class of nonlinear functional differential equations (fde) is established with the help of a transformation. The transformation reduces the fde to an ordinary differential equ...The unicity of the solution, if any, of a class of nonlinear functional differential equations (fde) is established with the help of a transformation. The transformation reduces the fde to an ordinary differential equation. Existence of the solution is established by means of a fixed point theorem.展开更多
The purpose of this paper is to study the theory of conservative estimating functions in nonlinear regression model with aggregated data. In this model, a quasi-score function with aggregated data is defined. When thi...The purpose of this paper is to study the theory of conservative estimating functions in nonlinear regression model with aggregated data. In this model, a quasi-score function with aggregated data is defined. When this function happens to be conservative, it is projection of the true score function onto a class of estimation functions. By constructing, the potential function for the projected score with aggregated data is obtained, which have some properties of log-likelihood function.展开更多
In the paper Lyapunov function for a fourth order linear system is given and stability of the trivial solutions to a class of.fourth order nonlinear systems is studied
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)under Grants 11971156 and 12001175.
摘要Let Fpm be a finite field with pm elements,where p is an odd prime and m is a positive integer.Recently,[17]and[35]determined the weight distributions of subfield codes with the form C f={((T r(a f(x)+b x)+c)_(x∈Fpm),T r(a)):a,b∈Fpm,c∈Fp}for f(x)=x2 and f(x)=x p k+1,respectively,where Tr(⋅)is the trace function from Fpm to Fp,and k is a nonnegative integer.In this paper,we further investigate the subfield code C f for f(x)being a known perfect nonlinear function over Fpm and generalize some results in[17,35].The weight distributions of the constructed codes are determined by applying the theory of quadratic forms and the properties of perfect nonlinear functions over finite fields.In addition,the parameters of the duals of these codes are also determined.Several examples show that some of our codes and their duals have the best known parameters according to the code tables in[16].The duals of some proposed codes are optimal according to the Sphere Packing bound if p≥5.
基金Sponsored by the Education Department Science and Technology Foundation of Heilongjiang Province (Grant No.11531324)
摘要The existence and representation of the exact solution are given for a nonlinear functional equation in the reproducing kernel space. For a numerical computation, we present a large-range convergence iterative method for solving the nonlinear functional equation. In the iterative method, the convergent condition is simple and the convergence is irrespective to the choice of the initial function. It is worthy to note that the presented method can be generalized to solve other nonlinear operator equations.
摘要The main objective of this article is to study the oscillatory behavior of the solutions of the following nonlinear functional differential equations(a(t)x'(t))'+δ1p(t)x'(t) +δ2q(t)f(x(g(t))) = 0,for 0 ≤ to≤ t, where 51 = :El and δ±1. The functions p,q,g : [t0, ∞) → R, f : R → are continuous, a(t) 〉 0,p(t) ≥0,q(t) 〉 0 for t ≥ to,lirn g(t) = ∞, and q is not identically zero on any subinterval of [to, ∞). Moreover, the functions q(t), g(t), and a(t) are continuously differentiable.
摘要Nonlinear computation is essential for a wide range of information processing tasks,yet implementing nonlinear functions using optical systems remains a challenge due to the weak and power-intensive nature of optical nonlinearities.Overcoming this limitation without relying on nonlinear optical materials could unlock unprecedented opportunities for ultrafast and parallel optical computing systems.Here,we demonstrate that large-scale nonlinear computation can be performed using linear optics through optimized diffractive processors composed of passive phase-only surfaces.In this framework,the input variables of nonlinear functions are encoded into the phase of an optical wavefront—e.g.,via a spatial light modulator(SLM)—and transformed by an optimized diffractive structure with spatially varying point-spread functions to yield output intensities that approximate a large set of unique nonlinear functions–all in parallel.We provide proof establishing that this architecture serves as a universal function approximator for an arbitrary set of bandlimited nonlinear functions,also covering wavelength-multiplexed nonlinear functions as well as multi-variate and complex-valued functions that are all-optically cascadable.Our analysis also indicates the successful approximation of typical nonlinear activation functions commonly used in neural networks,including the sigmoid,tanh,ReLU(rectified linear unit),and softplus.We numerically demonstrate the parallel computation of one million distinct nonlinear functions,accurately executed at wavelength-scale spatial density at the output of a diffractive optical processor.Furthermore,we experimentally validated this framework using in situ optical learning and approximated 35 unique nonlinear functions in a single shot using a compact setup consisting of an SLM and an image sensor.These results establish diffractive optical processors as a scalable platform for massively parallel universal nonlinear function approximation,paving the way for new capabilities in analog optical computing based on linear materials.
基金Supported by the National Natural Science Foundation of China Grant(11961047).
摘要In normed linear spaces,by applying the Minkowski difference,the concepts of efficient solutions,weakly efficient solutions,proper efficient solutions and Henig efficient solutions are introduced for set optimization with respect to co-radiant sets,and the relationships among them is discussed.Optimality conditions for minimal solutions and strictly minimal solutions of scalar set optimization are established by using the generalized oriented distance functions,respectively.The relationship between the solutions of set optimization problem and the solutions of scalar problem is studied.Several examples are given to explain our result.Properties of Gerstewitz’s functions with respect to co-radiant sets are discussed,which are used to establish sufficient conditions for weakly efficient solutions of set optimization.
基金Supported in part by the National Natural Science Foundation of China(Grant Nos 60573028,60803156)the Open Research Fund of the National Mobile Communications Research Laboratory of Southeast University(Grant No W200805)in part by Singapore Ministry of Education Academic Research Fund(Grant No T206B2204)
摘要A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented,which provides a kind of unified constructions of constant-composition codes based on all known perfect nonlinear functions from F qm to itself.It is proved that the new constant-composition codes are optimal with respect to the Luo-Fu-Vinck-Chen bound,when m is an odd positive integer greater than 1.Finally,we point out that two constructions of constant-composition codes,proposed by Ding Cunsheng et al.in 2005,are equivalent to two special types of the new constant-composition codes.
基金supported by the National Natural Science Foundation of China(U20A20187,U22A2050)the Science Fund of Hebei Province(F2024203134,F2023203100)+3 种基金the Science and Technology Development Grant of Hebei Province(20311803D)Hebei Innovation Capability Improvement Plan project(22567619H)Basic Research Project of Shijiazhuang(241791007A)the China Scholarship Council(CSC 202308130190).
摘要Dear Editor,This letter investigates the fuzzy prescribed-time control(PTC)problem for a class of uncertain pure feedback nonlinear systems.Firstly,a novel prescribed-time stability lemma is introduced,which plays a critical role in stability analysis.Unlike existing PTC algorithms,where the nonlinear functions are typically known or satisfy a linear growth condition,our approach does not require such assumptions.To address these unknown factors,fuzzy logic systems(FLSs)are employed.Based on the new prescribed-time stability lemma,it is proven that the controller and all system states converge to the origin within the prescribed time and remain there.Finally,the effectiveness of the proposed algorithm is validated through a simulation example.
基金the National Natural Science Foundation of China(Project Nos.12022213,11772205 and 11902203)the Scieatifie Research Fund of Liaoning Provineinl Education Department(No.L201703)+1 种基金the Program of Liaoning Revitalization Talents(XLYC1807172)the Tralning Project of Liaoning Higher Education Institutions in Domestic and Oveseas(Nos.2018LNGXGJWPY-YB008).
摘要In order to improve the harsh dynamic environment experienced by heavy rockets during different external excitations,this study presents a novel active variable stiffness vibration isolator(AVS-VI)used as the vibration isolation device to reduce excessive vibration of the whole-spacecraft isolation system.The AVS-VI is composed of horizontal stiffness spring,positive stiffness spring,parallelogram linkage mechanism,piezoelectric actuator,acceleration sensor,viscoelastic damping,and PID active controller.Based on the AVS-VI,the generalized vibration transmissibility determined by the nonlinear output frequency response functions and the energy absorption rate is applied to analyze the isolation performance of the whole-spacecraft system with AVS-VI.The AVS-VI can conduct adaptive vibration suppression with variable stiffness to the whole-spacecraft system,and the analysis results indicate that the AVS-VI is efTective in reducing the extravagant vibration of the whole-spacecraft system,where the vibration isolation is decreased up to above 65%under different acceleration excitations.Finally,different parameters of AVS-VI are considered to optimize the whole-spacecraft system based on the generalized vibration transmissibility and the energy absorption rate.
基金Project supported by the National Natural Science Foundation of China (Grant No 10674087)973 Program (Grant Nos 2006CB921603 and 2008CB317103)+2 种基金the Natural Science Foundation of Shanxi Province of China (Grant No 200611004)NCET(NCET-06-0259)IMR SYNL-T.S. Kê Research Fellowship
摘要The nonlinear Wannier functions in square Kronig-Penney potential are investigated with the help of a set of exact nonlinear Bloch solutions. The nonlinear interaction makes the Wannier functions fall off as non-exponential law with distance and enhances the tunneling coupling between the neighbor sites.
基金supported by the National Science Foundation of China (70771080)Social Science Foundation of Ministry of Education (10YJC630233)
摘要The penalty function method, presented many years ago, is an important nu- merical method for the mathematical programming problems. In this article, we propose a dual-relax penalty function approach, which is significantly different from penalty func- tion approach existing for solving the bilevel programming, to solve the nonlinear bilevel programming with linear lower level problem. Our algorithm will redound to the error analysis for computing an approximate solution to the bilevel programming. The error estimate is obtained among the optimal objective function value of the dual-relax penalty problem and of the original bilevel programming problem. An example is illustrated to show the feasibility of the proposed approach.
基金Supported by the Scientific Research Fund of Sichuan Provincial Education Department(Grant No.14ZB0364)
摘要In this paper, we consider a general nonlinear integral operator Hαi, βi ( f1,..., fn ; g1,..., gn)(z). Some results including coefficient problems, univalency condition and radius of convexity for this integral operator are given. Furthermore, we discuss the mapping properties between Hαi,βi (f1 , fn, ; g1,..., gn)(z) and subclasses of analytic functions with bounded boundary rotation. The same subjects for some corresponding classes are shown upon specializing the parameters in our main results.
摘要In this paper an orthogonal function method is presented based on the idea to suppose perioche sohuion with the method of harmonie balance The displaeement is expressed in the form of trigonometric fumctions a group of simplified digenequationsare obtained by the use of orthogonarity of trigonometric fumetions and linear mondes The method overcomes the diffieulty of a drifi term existing in systems with quadratic nonlinearities .The ealeulation examples show that the method has thd advantages of high caleulation preeision high convergenee speed and littld ealeulation work
基金the National Natural Science Foundation of Chinafor Innovative Research Groups Under Grant No.50621062the National Natural Science Foundation of China forYoung Scholars Under Grant No.10402030
摘要The joint probability density fimction (PDF) of different structural responses is a very important topic in the stochastic response analysis of nonlinear structures. In this paper, the probability density evolution method, which is successfully developed to capture the instantaneous PDF of an arbitrary single response of interest, is extended to evaluate the joint PDF of any two responses. A two-dimensional partial differential equation in terms of the joint PDF is established. The strategy of selecting representative points via the number theoretical method and sieved by a hyper-ellipsoid is outlined. A two-dimensional difference scheme is developed. The free vibration of an SDOF system is examined to verify the proposed method, and a flame structure exhibiting hysteresis subjected to stochastic ground motion is investigated. It is pointed out that the correlation of different responses results from the fact that randomness of different responses comes from the same set of basic random parameters involved. In other words, the essence of the probabilistic correlation is a physical correlation.
基金Project supported by the National Natural Science Foundation of China(Grant No.11175113)
摘要We explore the theoretical possibility of extending the usual squeezed state to those produced by nonlinear singlemode squeezing operators. We derive the wave functions of exp[-(ig/2)((1-X2)1/2P + P(1-X2)1/2)]|0 in the coordinate representation. A new operator's disentangling formula is derived as a by-product.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10571137,10771162)
摘要A mechanism for proving global convergence in filter-SQP (sequence of quadratic programming) method with the nonlinear complementarity problem (NCP) function is described for constrained nonlinear optimization problem.We introduce an NCP function into the filter and construct a new SQP-filter algorithm.Such methods are characterized by their use of the dominance concept of multi-objective optimization,instead of a penalty parameter whose adjustment can be problematic.We prove that the algorithm has global convergence and superlinear convergence rates under some mild conditions.
摘要An exact augmented Lagrangian function for the nonlinear nonconvex programming problems with inequality constraints was discussed. Under suitable hypotheses, the relationship was established between the local unconstrained minimizers of the augmented Lagrangian function on the space of problem variables and the local minimizers of the original constrained problem. Furthermore, under some assumptions, the relationship was also established between the global solutions of the augmented Lagrangian function on some compact subset of the space of problem variables and the global solutions of the constrained problem. Therefore, f^om the theoretical point of view, a solution of the inequality constrained problem and the corresponding values of the Lagrange multipliers can be found by the well-known method of multipliers which resort to the unconstrained minimization of the augmented Lagrangian function presented.
摘要Tool condition monitoring(TCM)is a key technology for intelligent manufacturing.The objective is to monitor the tool operation status and detect tool breakage so that the tool can be changed in time to avoid significant damage to workpieces and reduce manufacturing costs.Recently,an innovative TCM approach based on sensor data modelling and model frequency analysis has been proposed.Different from traditional signal feature-based monitoring,the data from sensors are utilized to build a dynamic process model.Then,the nonlinear output frequency response functions,a concept which extends the linear system frequency response function to the nonlinear case,over the frequency range of the tooth passing frequency of the machining process are extracted to reveal tool health conditions.In order to extend the novel sensor data modelling and model frequency analysis to unsupervised condition monitoring of cutting tools,in the present study,a multivariate control chart is proposed for TCM based on the frequency domain properties of machining processes derived from the innovative sensor data modelling and model frequency analysis.The feature dimension is reduced by principal component analysis first.Then the moving average strategy is exploited to generate monitoring variables and overcome the effects of noises.The milling experiments of titanium alloys are conducted to verify the effectiveness of the proposed approach in detecting excessive flank wear of solid carbide end mills.The results demonstrate the advantages of the new approach over conventional TCM techniques and its potential in industrial applications.
摘要The unicity of the solution, if any, of a class of nonlinear functional differential equations (fde) is established with the help of a transformation. The transformation reduces the fde to an ordinary differential equation. Existence of the solution is established by means of a fixed point theorem.
摘要The purpose of this paper is to study the theory of conservative estimating functions in nonlinear regression model with aggregated data. In this model, a quasi-score function with aggregated data is defined. When this function happens to be conservative, it is projection of the true score function onto a class of estimation functions. By constructing, the potential function for the projected score with aggregated data is obtained, which have some properties of log-likelihood function.
摘要In the paper Lyapunov function for a fourth order linear system is given and stability of the trivial solutions to a class of.fourth order nonlinear systems is studied