This paper presents a predefined-time controller for Multiple Space transportation Robots System (MSRS), which can be applied in on-orbit assembly tasks to transport modules to pre-assembly configuration quickly. Firs...This paper presents a predefined-time controller for Multiple Space transportation Robots System (MSRS), which can be applied in on-orbit assembly tasks to transport modules to pre-assembly configuration quickly. Firstly, to simplify the analysis and design of predefined-time controller, a Predefined-time Stability Criterion is proposed in the form of Composite Lyapunov Function (CLF-PSC). Besides simplicity, the CLF-PSC also has the advantage of less conservativeness due to utilization of initial state information. Secondly, a concept of Lp-Norm-Normalized Sign Function (LPNNSF) is proposed based on the CLF-PSC. Different from traditional norm-normalized sign function, the Lp-norm of LPNNSF can be selected arbitrarily according to practical control task requirements, which means that the proposed LPNNSF is more generalized and more convenient for calculation. Thirdly, a predefined-time disturbance observer and predefined-time controller are designed based on the LPNNSF. The observer has the property of predefined-time convergence to achieve quicker and more accurate estimation of the lumped disturbance. The controller has less control input and chattering phenomenon than traditional predefined-time controller. In addition, by introducing the observer into the controller, the closed-loop system enjoys high precision and strong robustness. Finally, the effectiveness of the proposed controller is verified by numerical simulations. By employing the controller, the MSRS can carry assembly modules to the desired pre-assembly configuration accurately within predefined time.展开更多
In this paper, the multistability issue is discussed for delayed complex-valued recurrent neural networks with discontinuous real-imaginary-type activation functions. Based on a fixed theorem and stability definition,...In this paper, the multistability issue is discussed for delayed complex-valued recurrent neural networks with discontinuous real-imaginary-type activation functions. Based on a fixed theorem and stability definition, sufficient criteria are established for the existence and stability of multiple equilibria of complex-valued recurrent neural networks. The number of stable equilibria is larger than that of real-valued recurrent neural networks, which can be used to achieve high-capacity associative memories. One numerical example is provided to show the effectiveness and superiority of the presented results.展开更多
In this paper, we investigate one kind of complex-valued systems with an impulsive control field, where the complex-valued system is governed by the Schrödinger equation, which is used for quantum systems, etc. W...In this paper, we investigate one kind of complex-valued systems with an impulsive control field, where the complex-valued system is governed by the Schrödinger equation, which is used for quantum systems, etc. We study the convergence of the complex-valued system with impulsive control fields by one Lyapunov function based on the state distance and the invariant principle of impulsive systems. We propose new results for the mentioned complex-valued systems in the form of sufficient conditions and also present one numerical simulation to illustrate the effectiveness of the proposed control method.展开更多
Stability criteria for the complex-valued impulsive system are applied widely in many fields, such as quantum systems, which have been studied in recent decades. In this paper, I investigate the Lyapunov control of fi...Stability criteria for the complex-valued impulsive system are applied widely in many fields, such as quantum systems, which have been studied in recent decades. In this paper, I investigate the Lyapunov control of finite dimensional complex-valued systems with impulsive control fields, where the studied complex-valued systems are governed by the Schrödinger equation and can be used in quantum systems. By one Lyapunov function based on state error and the invariant principle of impulsive systems, I study the convergence of complex-valued systems with impulsive control fields and propose new results for the mentioned complex-valued systems in the form of sufficient conditions. A numerical simulation to validate the proposed control method is provided.展开更多
Complex-valued neural networks(CVNNs)have shown their excellent efficiency compared to their real counterparts in speech enhancement,image and signal processing.Researchers throughout the years have made many efforts ...Complex-valued neural networks(CVNNs)have shown their excellent efficiency compared to their real counterparts in speech enhancement,image and signal processing.Researchers throughout the years have made many efforts to improve the learning algorithms and activation functions of CVNNs.Since CVNNs have proven to have better performance in handling the naturally complex-valued data and signals,this area of study will grow and expect the arrival of some effective improvements in the future.Therefore,there exists an obvious reason to provide a comprehensive survey paper that systematically collects and categorizes the advancement of CVNNs.In this paper,we discuss and summarize the recent advances based on their learning algorithms,activation functions,which is the most challenging part of building a CVNN,and applications.Besides,we outline the structure and applications of complex-valued convolutional,residual and recurrent neural networks.Finally,we also present some challenges and future research directions to facilitate the exploration of the ability of CVNNs.展开更多
In this paper, a novel design procedure is proposed for synthesizing high-capacity auto-associative memories based on complex-valued neural networks with real-imaginary-type activation functions and constant delays. S...In this paper, a novel design procedure is proposed for synthesizing high-capacity auto-associative memories based on complex-valued neural networks with real-imaginary-type activation functions and constant delays. Stability criteria dependent on external inputs of neural networks are derived. The designed networks can retrieve the stored patterns by external inputs rather than initial conditions. The derivation can memorize the desired patterns with lower-dimensional neural networks than real-valued neural networks, and eliminate spurious equilibria of complex-valued neural networks. One numerical example is provided to show the effectiveness and superiority of the presented results.展开更多
In this paper, we consider the generalized translations associated with the Dunkl and the Jacobi-Dunkl differential-difference operators on the real line which provide the structure of signed hrpergroups on R. Especia...In this paper, we consider the generalized translations associated with the Dunkl and the Jacobi-Dunkl differential-difference operators on the real line which provide the structure of signed hrpergroups on R. Especially, we study the representation of the gener- alized translations of the product of two functions for these signed hypergroups.展开更多
With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study and travel. To help the foreigners better understand China and facilitate cross-cultural comm...With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study and travel. To help the foreigners better understand China and facilitate cross-cultural communication, bilingual or even trilingual public signs spring up in every part of China. As is known that public signs, usually in the form of a few words, a picture or words accompanied with a picture, function not only as a " face" of a city and a nation, but also as a first calling card given to the foreigners. Moreover, public signs have definite functions-informing, warning or directing. However, to our disappointment, mistranslations of the public signs are present everywhere.展开更多
This paper describes an approximated-scalar-sign-function-based anti-windup digital control design for analog nonlinear systems subject to input constraints. As input saturation occurs, the non-smooth saturation const...This paper describes an approximated-scalar-sign-function-based anti-windup digital control design for analog nonlinear systems subject to input constraints. As input saturation occurs, the non-smooth saturation constraint is modeled with the approximated scalar sign function which is a smooth nonlinear function. The resulting nonlinear model is further linearized at any operating point with the optimal linearization technique, and Linear Quadratic Regulator (LQR) is then applied for a state-feedback controller optimal for each operating point. As input saturation is encountered, an iterative procedure is developed to adjust control gains by systematically updating LQR weighting matrices until the inputs lie within the saturation limits. Through global digital redesign, the analog LQR controller is converted to an equivalent digital one for keeping the essential control performance, and moreover, delay compensation is taken into account during digital redesign for compensating the potential time delays in a control loop. The swing-up and stabilization control of single rotary inverted pendulum system is used to illustrate and verify the proposed method.展开更多
With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study, and travel. To help the foreigners better understand China and facilitate cross-cultural com...With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study, and travel. To help the foreigners better understand China and facilitate cross-cultural communication, bilingual or even trilingual public signs spring up in every part of China. As is known that public signs, usually in the form of a few words, pictures, or words accompanied with a picture, function not only as a＂face＂ of a city and a nation, but also as a first calling card given to the foreigners. Moreover, public signs have definite functions--informing, warning, or directing. However, to our disappointment, mistranslations of the public signs are often presented in some places. As a special text whose function is strong and communicative purpose is quite clear, the translation of public signs should be based on the text＇s functions and the translator＇s purpose. This paper classifies public signs, compares Chinese signs with English ones, and comes up with the principle for its Chinese-English translation, namely, an A-B-C approach （Adapt-Borrow-Create approach） which is based on the Skopostheorie.展开更多
Based on Nida’s Functional Equivalence theory,this article makes an analysis of the problems in C-E translations ofsigns in China.The author will discuss respectively the problematic C-E translations from two respect...Based on Nida’s Functional Equivalence theory,this article makes an analysis of the problems in C-E translations ofsigns in China.The author will discuss respectively the problematic C-E translations from two respects:1)not being equivalent tosource-language message,and 2)not being natural for target language.If translators work hard with the help of Nida’s functionalequivalence theory,the defects and imperfections will be discovered,and standard signs in English will be read more and more inpublic places.展开更多
In this paper,the authors obtain the existence of one-signed periodic solutions of the first-order functional difference equation ？u（n） = a（n）u（n）-λb（n）f（u（n-τ（n）））,n ∈ Z by using global bifurcation ...In this paper,the authors obtain the existence of one-signed periodic solutions of the first-order functional difference equation ？u（n） = a（n）u（n）-λb（n）f（u（n-τ（n）））,n ∈ Z by using global bifurcation techniques,where a,b：Z → [0,∞） are T-periodic functions with ∑T n=1 a（n） 〉 0,∑T n=1 b（n） 〉 0;τ：Z → Z is T-periodic function,λ 〉 0 is a parameter;f ∈ C（R,R） and there exist two constants s2 〈 0 〈 s1 such that f（s2） = f（0） = f（s1） = 0,f（s） 〉 0 for s ∈（0,s1） ∪（s1,∞）,and f（s） 〈 0 for s ∈（-∞,s2） ∪（s2,0）.展开更多
This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones a...This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.12372048,12102343)the Key Program of the National Natural Science Foundation of China(No.U2013206)+1 种基金the China Postdoctoral Science Foundation(No.2023M742835)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023A1515011421).
文摘This paper presents a predefined-time controller for Multiple Space transportation Robots System (MSRS), which can be applied in on-orbit assembly tasks to transport modules to pre-assembly configuration quickly. Firstly, to simplify the analysis and design of predefined-time controller, a Predefined-time Stability Criterion is proposed in the form of Composite Lyapunov Function (CLF-PSC). Besides simplicity, the CLF-PSC also has the advantage of less conservativeness due to utilization of initial state information. Secondly, a concept of Lp-Norm-Normalized Sign Function (LPNNSF) is proposed based on the CLF-PSC. Different from traditional norm-normalized sign function, the Lp-norm of LPNNSF can be selected arbitrarily according to practical control task requirements, which means that the proposed LPNNSF is more generalized and more convenient for calculation. Thirdly, a predefined-time disturbance observer and predefined-time controller are designed based on the LPNNSF. The observer has the property of predefined-time convergence to achieve quicker and more accurate estimation of the lumped disturbance. The controller has less control input and chattering phenomenon than traditional predefined-time controller. In addition, by introducing the observer into the controller, the closed-loop system enjoys high precision and strong robustness. Finally, the effectiveness of the proposed controller is verified by numerical simulations. By employing the controller, the MSRS can carry assembly modules to the desired pre-assembly configuration accurately within predefined time.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61374094 and 61503338)the Natural Science Foundation of Zhejiang Province,China(Grant No.LQ15F030005)
文摘In this paper, the multistability issue is discussed for delayed complex-valued recurrent neural networks with discontinuous real-imaginary-type activation functions. Based on a fixed theorem and stability definition, sufficient criteria are established for the existence and stability of multiple equilibria of complex-valued recurrent neural networks. The number of stable equilibria is larger than that of real-valued recurrent neural networks, which can be used to achieve high-capacity associative memories. One numerical example is provided to show the effectiveness and superiority of the presented results.
文摘In this paper, we investigate one kind of complex-valued systems with an impulsive control field, where the complex-valued system is governed by the Schrödinger equation, which is used for quantum systems, etc. We study the convergence of the complex-valued system with impulsive control fields by one Lyapunov function based on the state distance and the invariant principle of impulsive systems. We propose new results for the mentioned complex-valued systems in the form of sufficient conditions and also present one numerical simulation to illustrate the effectiveness of the proposed control method.
文摘Stability criteria for the complex-valued impulsive system are applied widely in many fields, such as quantum systems, which have been studied in recent decades. In this paper, I investigate the Lyapunov control of finite dimensional complex-valued systems with impulsive control fields, where the studied complex-valued systems are governed by the Schrödinger equation and can be used in quantum systems. By one Lyapunov function based on state error and the invariant principle of impulsive systems, I study the convergence of complex-valued systems with impulsive control fields and propose new results for the mentioned complex-valued systems in the form of sufficient conditions. A numerical simulation to validate the proposed control method is provided.
基金partially supported by the JSPS KAKENHI(JP22H03643,JP19K22891)。
文摘Complex-valued neural networks(CVNNs)have shown their excellent efficiency compared to their real counterparts in speech enhancement,image and signal processing.Researchers throughout the years have made many efforts to improve the learning algorithms and activation functions of CVNNs.Since CVNNs have proven to have better performance in handling the naturally complex-valued data and signals,this area of study will grow and expect the arrival of some effective improvements in the future.Therefore,there exists an obvious reason to provide a comprehensive survey paper that systematically collects and categorizes the advancement of CVNNs.In this paper,we discuss and summarize the recent advances based on their learning algorithms,activation functions,which is the most challenging part of building a CVNN,and applications.Besides,we outline the structure and applications of complex-valued convolutional,residual and recurrent neural networks.Finally,we also present some challenges and future research directions to facilitate the exploration of the ability of CVNNs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61503338,61573316,61374152,and 11302195)the Natural Science Foundation of Zhejiang Province,China(Grant No.LQ15F030005)
文摘In this paper, a novel design procedure is proposed for synthesizing high-capacity auto-associative memories based on complex-valued neural networks with real-imaginary-type activation functions and constant delays. Stability criteria dependent on external inputs of neural networks are derived. The designed networks can retrieve the stored patterns by external inputs rather than initial conditions. The derivation can memorize the desired patterns with lower-dimensional neural networks than real-valued neural networks, and eliminate spurious equilibria of complex-valued neural networks. One numerical example is provided to show the effectiveness and superiority of the presented results.
文摘In this paper, we consider the generalized translations associated with the Dunkl and the Jacobi-Dunkl differential-difference operators on the real line which provide the structure of signed hrpergroups on R. Especially, we study the representation of the gener- alized translations of the product of two functions for these signed hypergroups.
文摘With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study and travel. To help the foreigners better understand China and facilitate cross-cultural communication, bilingual or even trilingual public signs spring up in every part of China. As is known that public signs, usually in the form of a few words, a picture or words accompanied with a picture, function not only as a " face" of a city and a nation, but also as a first calling card given to the foreigners. Moreover, public signs have definite functions-informing, warning or directing. However, to our disappointment, mistranslations of the public signs are present everywhere.
文摘This paper describes an approximated-scalar-sign-function-based anti-windup digital control design for analog nonlinear systems subject to input constraints. As input saturation occurs, the non-smooth saturation constraint is modeled with the approximated scalar sign function which is a smooth nonlinear function. The resulting nonlinear model is further linearized at any operating point with the optimal linearization technique, and Linear Quadratic Regulator (LQR) is then applied for a state-feedback controller optimal for each operating point. As input saturation is encountered, an iterative procedure is developed to adjust control gains by systematically updating LQR weighting matrices until the inputs lie within the saturation limits. Through global digital redesign, the analog LQR controller is converted to an equivalent digital one for keeping the essential control performance, and moreover, delay compensation is taken into account during digital redesign for compensating the potential time delays in a control loop. The swing-up and stabilization control of single rotary inverted pendulum system is used to illustrate and verify the proposed method.
文摘With the rapid development of Chinese economy, more and more foreigners have been attracted to China to invest, work, study, and travel. To help the foreigners better understand China and facilitate cross-cultural communication, bilingual or even trilingual public signs spring up in every part of China. As is known that public signs, usually in the form of a few words, pictures, or words accompanied with a picture, function not only as a＂face＂ of a city and a nation, but also as a first calling card given to the foreigners. Moreover, public signs have definite functions--informing, warning, or directing. However, to our disappointment, mistranslations of the public signs are often presented in some places. As a special text whose function is strong and communicative purpose is quite clear, the translation of public signs should be based on the text＇s functions and the translator＇s purpose. This paper classifies public signs, compares Chinese signs with English ones, and comes up with the principle for its Chinese-English translation, namely, an A-B-C approach （Adapt-Borrow-Create approach） which is based on the Skopostheorie.
文摘Based on Nida’s Functional Equivalence theory,this article makes an analysis of the problems in C-E translations ofsigns in China.The author will discuss respectively the problematic C-E translations from two respects:1)not being equivalent tosource-language message,and 2)not being natural for target language.If translators work hard with the help of Nida’s functionalequivalence theory,the defects and imperfections will be discovered,and standard signs in English will be read more and more inpublic places.
基金Supported by the National Natural Science Foundation of China(Grant Nos.1162618811671322+2 种基金11501451)the Natural Science Foundation of Gansu Province(Grant No.1606RJYA232)the Young Teachers’ Scientific Research Capability Upgrading Project of Northwest Normal University(Grant No.NWNU-LKQN-15-16)
文摘In this paper,the authors obtain the existence of one-signed periodic solutions of the first-order functional difference equation ？u（n） = a（n）u（n）-λb（n）f（u（n-τ（n）））,n ∈ Z by using global bifurcation techniques,where a,b：Z → [0,∞） are T-periodic functions with ∑T n=1 a（n） 〉 0,∑T n=1 b（n） 〉 0;τ：Z → Z is T-periodic function,λ 〉 0 is a parameter;f ∈ C（R,R） and there exist two constants s2 〈 0 〈 s1 such that f（s2） = f（0） = f（s1） = 0,f（s） 〉 0 for s ∈（0,s1） ∪（s1,∞）,and f（s） 〈 0 for s ∈（-∞,s2） ∪（s2,0）.
文摘This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique.
