摘要：
This paper focuses the initial boundary value problem to the compressible Oldroyd-B model in the two-dimensional space with vacuum. We establish a new blowup criterion in terms of parallel to rho parallel to L infinity tBMOx only. This work can be viewed as an extension of Lu and Zhang [Relative entropy, weak-strong uniqueness, and conditional regularity for a compressible Oldroyd-B model, SIAM J. Math. Anal., 50(2018), 557-590] where a blowup criterion involving the upper bound of the fluid density in the two-dimensional setting has been given.
摘要：
This paper investigates the role of time–frequency information in dimension reduction prediction of stock returns. Using the long-term wavelet component of monthly S&P500 excess returns as supervision, we employ a machine learning method to extract the common predictive factor from prevalent macroeconomic variables and construct a new macroeconomic index aligned with stock return prediction. The macroeconomic index exhibits significant predictive power, both in and out of sample, at the market and portfolio levels. It outperforms all individual macroeconomic predictors and the factors based on higher frequency information of realized returns. Our findings demonstrate substantial economic value of the new index in asset allocation. Moreover, we also observe a complementary relation between macroeconomic index and investor sentiment. The predictive power is most pronounced during high-economic-uncertainty periods when investors are likely to underreact to fundamental signals and stems from cash flow predictability channel.
This paper investigates the role of time–frequency information in dimension reduction prediction of stock returns. Using the long-term wavelet component of monthly S&P500 excess returns as supervision, we employ a machine learning method to extract the common predictive factor from prevalent macroeconomic variables and construct a new macroeconomic index aligned with stock return prediction. The macroeconomic index exhibits significant predictive power, both in and out of sample, at the market and portfolio levels. It outperforms all individual macroeconomic predictors and the factors based on higher frequency information of realized returns. Our findings demonstrate substantial economic value of the new index in asset allocation. Moreover, we also observe a complementary relation between macroeconomic index and investor sentiment. The predictive power is most pronounced during high-economic-uncertainty periods when investors are likely to underreact to fundamental signals and stems from cash flow predictability channel.
关键词：
KdV-KdV systems;Fourier-Galerkin methods;Hamiltonian boundary value methods;Blended iteration;Energy preservation
摘要：
In this paper, we propose a highly accurate scheme for two KdV systems of the Boussinesq type under periodic boundary conditions. The proposed scheme combines the Fourier-Galerkin method for spatial discretization with Hamiltonian boundary value methods for time integration, ensuring the conservation of discrete mass and energy. By expanding the system in Fourier series, the equations are firstly transformed into Hamiltonian form, preserving the original Hamiltonian structure. Applying the Fourier-Galerkin method for semi-discretization in space, we obtain a large-scale system of Hamiltonian ordinary differential equations, which is then solved using a class of energy-conserving Runge-Kutta methods, known as Hamiltonian boundary value methods. The efficiency of this approach is assessed, and several numerical examples are provided to demonstrate the effectiveness of the method.
In this paper, we propose a highly accurate scheme for two KdV systems of the Boussinesq type under periodic boundary conditions. The proposed scheme combines the Fourier-Galerkin method for spatial discretization with Hamiltonian boundary value methods for time integration, ensuring the conservation of discrete mass and energy. By expanding the system in Fourier series, the equations are firstly transformed into Hamiltonian form, preserving the original Hamiltonian structure. Applying the Fourier-Galerkin method for semi-discretization in space, we obtain a large-scale system of Hamiltonian ordinary differential equations, which is then solved using a class of energy-conserving Runge-Kutta methods, known as Hamiltonian boundary value methods. The efficiency of this approach is assessed, and several numerical examples are provided to demonstrate the effectiveness of the method.
摘要：
Given the critical role of diffusion in material design, particularly its relationship with composition and structure, this study focuses on the diffusion properties in the Co-Fe-X (X=V/Mn) ternary systems, which are key sub-systems of high-entropy alloys. To carefully evaluate the interdiffusivity and atomic mobility for fcc Co-Fe-X (X=V/Mn) phase, annealing is performed at 1273, 1373, and 1473 K on 12 diffusion couples for each ternary system. EPMA (Electron Probe Microanalysis) is used to measure composition profiles after annealing. To provide more reliable diffusion coefficients, atomic mobilities in fcc Co-V and Fe-Mn phases are re-optimized in this work. Subsequently, by employing the composition profiles and corresponding experimental conditions, the interdiffusivity and atomic mobility for fcc Co-Fe-X (X=V/Mn) phase are efficiently calculated through high-throughput NNIM (novel numerical inverse method) embedded in CALTPP (CALculation of ThermoPhysical Properties) software. The presently assessed interdiffusivities and atomic mobilities for fcc Co-Fe-X (X=V/Mn) phase are verified to be reliable as the NNIM-predicted composition profiles, interdiffusivities together with diffusion paths are consistent with the measured data. Moreover, key diffusion characteristics related to materials design associated with the fcc Co-Fe-X (X=V/Mn) phase are obtained and analyzed, including interdiffusivities, 2D composition profiles, frequency factors, and diffusion activation energies. The obtained atomic mobilities and diffusion characteristics demonstrate high reliability through experimental validation, which not only contributes to establishing the diffusion database but also provides crucial insights for designing high-entropy alloys.
Given the critical role of diffusion in material design, particularly its relationship with composition and structure, this study focuses on the diffusion properties in the Co-Fe-X (X=V/Mn) ternary systems, which are key sub-systems of high-entropy alloys. To carefully evaluate the interdiffusivity and atomic mobility for fcc Co-Fe-X (X=V/Mn) phase, annealing is performed at 1273, 1373, and 1473 K on 12 diffusion couples for each ternary system. EPMA (Electron Probe Microanalysis) is used to measure composition profiles after annealing. To provide more reliable diffusion coefficients, atomic mobilities in fcc Co-V and Fe-Mn phases are re-optimized in this work. Subsequently, by employing the composition profiles and corresponding experimental conditions, the interdiffusivity and atomic mobility for fcc Co-Fe-X (X=V/Mn) phase are efficiently calculated through high-throughput NNIM (novel numerical inverse method) embedded in CALTPP (CALculation of ThermoPhysical Properties) software. The presently assessed interdiffusivities and atomic mobilities for fcc Co-Fe-X (X=V/Mn) phase are verified to be reliable as the NNIM-predicted composition profiles, interdiffusivities together with diffusion paths are consistent with the measured data. Moreover, key diffusion characteristics related to materials design associated with the fcc Co-Fe-X (X=V/Mn) phase are obtained and analyzed, including interdiffusivities, 2D composition profiles, frequency factors, and diffusion activation energies. The obtained atomic mobilities and diffusion characteristics demonstrate high reliability through experimental validation, which not only contributes to establishing the diffusion database but also provides crucial insights for designing high-entropy alloys.
摘要：
This paper focuses on the existence of normalized solutions for the Chern–Simons–Schrödinger system with mixed dispersion and critical exponential growth. These solutions correspond to critical points of the underlying energy functional under the L 2 $$ {L}^2 $$ -norm constraint, namely, ∫ ℝ 2 u 2 d x = c > 0 $$ {\int}_{{\mathrm{\mathbb{R}}}^2}{u}^2\mathrm{d}x=c>0 $$ . Under certain mild assumptions, we establish the existence of nontrivial solutions by developing new mathematical strategies and analytical techniques for the given system. These results extend and improve the results in the existing literature.
摘要：
In this paper, the famous Bernfeld–Haddock conjecture is generalized to a broader form combining with a class of non-autonomous delay differential equations. With the help of differential inequality technique and Dini derivative theory, it is proved that each solution of the addressed equations has boundedness and tends to a constant without requiring the delay feedback function to be strictly increasing, which greatly refines and extends the corresponding results in the existing literature. In particular, an explanatory example is performed to substantiate the obtained analytical findings.
In this paper, the famous Bernfeld–Haddock conjecture is generalized to a broader form combining with a class of non-autonomous delay differential equations. With the help of differential inequality technique and Dini derivative theory, it is proved that each solution of the addressed equations has boundedness and tends to a constant without requiring the delay feedback function to be strictly increasing, which greatly refines and extends the corresponding results in the existing literature. In particular, an explanatory example is performed to substantiate the obtained analytical findings.
期刊：
International Journal of Approximate Reasoning,2025年:109516 ISSN：0888-613X
通讯作者：
Guangming Lang
作者机构：
School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China;Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China;[Mengjun Hu] Department of Mathematics and Computing Science, Saint Mary's University, Halifax, Nova Scotia, B3H 3C3, Canada;[Jing Liu; Guangming Lang] School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China<&wdkj&>Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China
通讯机构：
[Guangming Lang] S;School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China<&wdkj&>Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410114, PR China
摘要：
Most existing work on three-way conflict analysis has focused on trisecting agent pairs, agents, or issues. While these trisections lay the groundwork for understanding the nature of conflicts, further actions need to be formulated to address conflict resolution. One of the widely studied approaches is to construct feasible strategies. This paper aims to investigate feasible strategies from two perspectives of consistency and non-consistency. Particularly, we begin with computing the overall rating of a clique of agents based on positive and negative similarity degrees. Afterwards, considering the weights of both agents and issues, we propose weighted consistency and non-consistency measures, which are respectively used to identify the feasible strategies for a clique of agents. Algorithms are developed to identify feasible strategies, L -order feasible strategies, and the corresponding optimal ones. Finally, to demonstrate the practicality, effectiveness, and superiority of the proposed models, we apply them to two commonly used case studies on NBA labor negotiations and development plans for Gansu Province and conduct a sensitivity analysis on parameters and a comparative analysis with existing state-of-the-art conflict analysis approaches. The comparison results demonstrate that our conflict resolution models outperform the conventional approaches by unifying weighted agent-issue evaluation with consistency and non-consistency measures to enable the systematic identification of not only feasible strategies but also optimal solutions.
Most existing work on three-way conflict analysis has focused on trisecting agent pairs, agents, or issues. While these trisections lay the groundwork for understanding the nature of conflicts, further actions need to be formulated to address conflict resolution. One of the widely studied approaches is to construct feasible strategies. This paper aims to investigate feasible strategies from two perspectives of consistency and non-consistency. Particularly, we begin with computing the overall rating of a clique of agents based on positive and negative similarity degrees. Afterwards, considering the weights of both agents and issues, we propose weighted consistency and non-consistency measures, which are respectively used to identify the feasible strategies for a clique of agents. Algorithms are developed to identify feasible strategies, L -order feasible strategies, and the corresponding optimal ones. Finally, to demonstrate the practicality, effectiveness, and superiority of the proposed models, we apply them to two commonly used case studies on NBA labor negotiations and development plans for Gansu Province and conduct a sensitivity analysis on parameters and a comparative analysis with existing state-of-the-art conflict analysis approaches. The comparison results demonstrate that our conflict resolution models outperform the conventional approaches by unifying weighted agent-issue evaluation with consistency and non-consistency measures to enable the systematic identification of not only feasible strategies but also optimal solutions.
摘要：
This paper is devoted to the study of a nonlocal diffusion competition model with unbounded free boundaries. It is assumed that two competing species initially occupy their respective unbounded habitats and exhibit a tendency to expand with a free boundary. As time progresses, the habitats of these two species gradually overlap, giving rise to competition within the shared habitat. For this free boundary problem with nonlocal diffusion, we establish the global existence and uniqueness of the solution and prove the spreading-vanishing dichotomy. Further, the asymptotic spreading speed is also determined.
This paper is devoted to the study of a nonlocal diffusion competition model with unbounded free boundaries. It is assumed that two competing species initially occupy their respective unbounded habitats and exhibit a tendency to expand with a free boundary. As time progresses, the habitats of these two species gradually overlap, giving rise to competition within the shared habitat. For this free boundary problem with nonlocal diffusion, we establish the global existence and uniqueness of the solution and prove the spreading-vanishing dichotomy. Further, the asymptotic spreading speed is also determined.
期刊：
JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES,2025年111(2):e70091- ISSN：0024-6107
通讯作者：
Xu, RZ
作者机构：
[Lin, Qiang] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha, Peoples R China.;[Xu, Runzhang; Lin, Qiang] Harbin Engn Univ, Coll Math Sci, Harbin 150001, Peoples R China.
通讯机构：
[Xu, RZ ] H;Harbin Engn Univ, Coll Math Sci, Harbin 150001, Peoples R China.
摘要：
In this paper, we conduct a comprehensive study of the global well-posedness of solution for a class of nonlocal wave equations with variable-order fractional Laplacian and variable exponent nonlinearity by constructing a suitable framework of the variational theory. We first prove the local-in-time existence of the weak solution via the Galerkin approximation technique and fixed point theory. Then by constructing the potential well theory, we classify the initial data leading to the global existence and finite time blowup of the solution for three different initial energy cases, that is, subcritical initial energy case, critical initial energy case, and supercritical initial energy case. For the subcritical and critical initial energy cases, we show that the solution exists globally in time when the initial data belong to the stable manifold and blows up in finite time when the initial data belong to the unstable manifold. For the supercritical initial energy case, we observe some initial conditions that enable the finite time blow-up solution by an adapted concavity method, and the issue of global existence still remains unsolved. As a further study of finite time blowup, we estimate the upper and lower bounds of blow-up time by using different strategies, that is, applying some first-order differential inequality regardless of the different initial energy levels, to give a unified expression for the lower bound estimation for three initial energy levels. For the upper bound estimation, we utilize two second-order differential inequalities influenced by the different energy levels to give the upper bound estimations of the blow-up time at each initial energy level.
期刊：
Journal of Functional Analysis,2025年289(6):110981 ISSN：0022-1236
通讯作者：
Haohao Zheng
作者机构：
[Li, Jing] School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha 410114, China;[Liu, Yue] Department of Mathematics, University of Texas at Arlington, TX 76019, United States of America;[Wu, Yifei] School of Mathematical Sciences and Mathematical Institute / Ministry of Education Key Laboratory of NSLSCS, Nanjing Normal University, Nanjing 210023, China;[Zheng, Haohao] Center for Applied Mathematics, Tianjin University, Tianjin 300072, China
通讯机构：
[Haohao Zheng] C;Center for Applied Mathematics, Tianjin University, Tianjin 300072, China
摘要：
The nonlinear Klein-Gordon (KG) equation, ∂ t t u − Δ u + u = | u | p − 1 u , ( t , x ) ∈ R × R d is shown in the present paper to possess the solitary-wave solutions in the form of e i ω t ϕ ω , c → ( x − c → t ) with the parameters ω and c → ∈ R d satisfying | ω | < 1 − | c → | 2 and | c → | < 1 . By employing a new localized virial identity combined with the coercivity and modulation argument, it is demonstrated here that there exists a critical frequency ω ⁎ ( | c → | ) such that these localized solitary waves, when considered as solutions of the initial-value problem for the nonlinear KG equation, is dynamically stable when 1 < p < 1 + 4 d , | ω | > ω ⁎ ( | c → | ) and is dynamically unstable when 1 < p < 1 + 4 d , 0 < | ω | ≤ ω ⁎ ( | c → | ) or 1 + 4 d ≤ p < 1 + 4 d − 2 ( d ≥ 3 or 1 < p < ∞ if d = 1 , 2 ) to small perturbations.
The nonlinear Klein-Gordon (KG) equation, ∂ t t u − Δ u + u = | u | p − 1 u , ( t , x ) ∈ R × R d is shown in the present paper to possess the solitary-wave solutions in the form of e i ω t ϕ ω , c → ( x − c → t ) with the parameters ω and c → ∈ R d satisfying | ω | < 1 − | c → | 2 and | c → | < 1 . By employing a new localized virial identity combined with the coercivity and modulation argument, it is demonstrated here that there exists a critical frequency ω ⁎ ( | c → | ) such that these localized solitary waves, when considered as solutions of the initial-value problem for the nonlinear KG equation, is dynamically stable when 1 < p < 1 + 4 d , | ω | > ω ⁎ ( | c → | ) and is dynamically unstable when 1 < p < 1 + 4 d , 0 < | ω | ≤ ω ⁎ ( | c → | ) or 1 + 4 d ≤ p < 1 + 4 d − 2 ( d ≥ 3 or 1 < p < ∞ if d = 1 , 2 ) to small perturbations.
作者：
Hong Sang;Chongyi Cui;Peng Wang;Yi Liu;Chuangxia Huang;...
期刊：
IEEE Transactions on Automatic Control,2025年:1-8 ISSN：0018-9286
作者机构：
[Peng Wang] School of Mathematics and Statistics, Fuzhou University, Fuzhou, China;[Hong Sang; Chongyi Cui; Yi Liu] College of Marine Electrical Engineering, Dalian Maritime University, Dalian, China;[Chuangxia Huang] School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, China;School of Mathematics, Southeast University, Nanjing, China;Purple Mountain Laboratories, Nanjing, China
摘要：
Sampled-data-based event-triggered (SDET) communication techniques have found extensive applications in the research of synchronization and consensus in directed networks (DNs). However, as the quantity of nodes in a network expands, existing investigations encounter difficulties in obtaining solutions within finite computation times due to computational complexity. For coping with this scenario, a novel event-triggered pinning quasi-synchronization approach is explored in this research for a category of switched directed networks (SDNs) with sampling measurements. By developing a time-dependent Lyapunov-Krasovskii functional (LKF) and implementing a state-dependent switching strategy utilizing sampling measurements, sufficient conditions are formulated to assure that the synchronization errors are ultimately bounded in an exponential fashion. Different from previous relevant findings, the verification of matrix conditions in the derived synchronization criterion no longer depends on the number of nodes in networks, making it more suitable for large-scale SDNs. Ultimately, two simulation examples are incorporated to elucidate the applicability of the newly crafted synchronization methodology.
期刊：
ANNALI DI MATEMATICA PURA ED APPLICATA,2025年:1-32 ISSN：0373-3114
通讯作者：
Yu, MZ
作者机构：
[Xie, Weihong] Cent South Univ, Sch Math & Stat, HNP, LAMA, Changsha 410083, Hunan, Peoples R China.;[Yu, Mingzhu; Yu, MZ] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Yu, MZ ] C;Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 410083, Hunan, Peoples R China.
关键词：
FitzHugh-Nagumo system;Infinitely many positive solutions;Sign-changing solutions;Gluing methods
摘要：
In this article we present the existence of infinitely many non-radial positive or sign-changing solutions for the following FitzHugh–Nagumosystem:
$$\begin{aligned} \left\{ \begin{array}{ll} \Delta u-a(|x|)u+g(u)-\delta v=0, \quad & x\in \mathbb {R}^N,\\ \Delta v+u=0, & x\in \mathbb {R}^N,\\ u(x), ~v(x)\rightarrow 0, & \text{ as }~ |x|\rightarrow +\infty ,\\ \end{array}\right. \end{aligned}$$
where
$$N\ge 5$$
,
$$\delta >0$$
,
$$g(u)=(a_0+1)u^2-u^3$$
,
$$0<a_0<\frac{1}{2}$$
and
$$a(|x|)\in (0,\frac{1}{2})$$
satisfies some decay conditions at the infinity. More precisely, for any positive integer k large, there is a
$$\delta _k>0$$
such that for
$$0<\delta <\delta _k$$
, there exists positive solutions with 2k peaks, which are respectively concentrated at the vertices of a regular k-polygon on two circles in 3-dimensional space with the radium
$$r\sim k \ln k$$
and the height
$$h\sim \frac{1}{k}$$
. In addition, the sign-changing solutions with 2k peaks are evenly distributed on the equatorial
$$\textrm{T}=\{x\in \mathbb {R}^2:x_1^2+x_2^2=r^2\}$$
in the
$$(x_1, x_2)$$
-plane. As a by-product, we give the similar results of Schödinger-Poisson in
$$\mathbb {R}^N$$
for
$$N\ge 3$$
.
摘要：
This study introduces a novel discrete-time denoising complex neurodynamics model (referred to as the DTDCN model), which focuses on analyzing and discussing the computation of online dynamic complex generalized inverse matrices under various noisy environments. The proposed DTDCN method has inherent denoising capabilities and high accuracy in online computation. Theoretical analysis has established that the DTDCN model possesses the characteristics of 0-stability, consistency, and convergence. Additionally, experimental results have further reinforced the DTDCN model's efficacy and superiority in online calculations of dynamic complex generalized inverse matrices under various noisy conditions are further confirmed.
摘要：
In this article, we define the notion of n -cotorsion pairs in triangulated categories, which is a generalization of the classical cotorsion pairs. We prove that any mutation of an n -cotorsion pair is again an n -cotorsion pair. When n = 1 , this result generalizes the work of Zhou and Zhu for classical cotorsion pairs. As applications, we give a geometric characterization of n -cotorsion pairs in n -cluster categories of type A and give a geometric realization of mutation of n -cotorsion pairs via rotation of certain configurations of n -diagonals.
In this article, we define the notion of n -cotorsion pairs in triangulated categories, which is a generalization of the classical cotorsion pairs. We prove that any mutation of an n -cotorsion pair is again an n -cotorsion pair. When n = 1 , this result generalizes the work of Zhou and Zhu for classical cotorsion pairs. As applications, we give a geometric characterization of n -cotorsion pairs in n -cluster categories of type A and give a geometric realization of mutation of n -cotorsion pairs via rotation of certain configurations of n -diagonals.
摘要：
Using data from 33 countries between 2005 and 2019, we find a negative relationship between firms’ exposures to climate risk and their degree of maturity mismatch. Moreover, channel tests show that climate risk depresses corporate maturity mismatch through two potential channels: decreased investment demand and increased difficulty in raising capital. Cross-sectional tests show that this negative effect is stronger among firms vulnerable to climate change, firms that rely more on external financing, and firms subject to lower growth options. Further analysis indicates that the negative relationship between climate risk and maturity mismatch is more pronounced in countries with lower economic development, weaker legal institutions, and lower climate resilience. Overall, our findings demonstrate that climate risk constitutes an essential consideration in firms’ maturity structure arrangements between investment and financing.
作者机构：
[Chang, Xiaoming; Dai, Zhifeng; Zhu, Haoyang] Changsha Univ Sci & Technol, Coll Math & Stat, Changsha 410114, Hunan, Peoples R China.;[Wen, Fenghua; Wen, FH] Cent South Univ, Coll Business, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Wen, FH ] C;Cent South Univ, Coll Business, Changsha 410083, Hunan, Peoples R China.
关键词：
Stock returns;The Japanese candlestick;CBOE volatility index fundamental predictors
摘要：
AbstractThis paper proposes a new predictor by calculating the difference between the Japanese candlestick’s upper and lower shadows (ULD) constructed from CBOE volatility index (VIX) data. ULD is a powerful predictor for future stock returns, and higher ULD leads to the subsequent decline of stock returns. Our results show that our new predictor generates R^2 values of up to 2.531% and 3.988% in-sample and out-of-sample, respectively; these values are much larger than the previous fundamental predictors. Moreover, the predictive information contained in ULD can help mean–variance investors achieve certainty equivalent return gains of as high as 327.1 basis points. Finally, the extension analysis and robustness tests indicate that recession is the primary cause of return predictability; our results are robust under different settings.
通讯机构：
[Wang, F ] C;Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 100190, Peoples R China.
关键词：
Fisher equation;Stream temperature equation;Diffusive SIS model;Global stability
摘要：
In this paper, the global stabilization of solutions to the initial-boundary value problem for the coupled model of the Fisher equation and Stream temperature equation (i.e., Fisher–Stream model) is studied. It is shown that under the non-homogeneous Dirichlet condition, the large time behavior of model analytical solutions is controlled by boundary conditions. Promoting to application, we establish similar conclusions in the coupled equation of the SIS model and Stream temperature equation.
摘要：
The precise baseline determination (PBD) is a crucial technique for spaceborne Interferometric Synthetic Aperture Radar (InSAR) formation-flying satellites to successfully carry out scientific missions. The Chinese InSAR formation T-A and T-B satellites are equipped with the multi-GNSS receiver that can track Global Positioning System (GPS) and BeiDou satellite navigation System (BDS-3) signals for PBD. First, we evaluate the data quality of spaceborne GPS and BDS-3 observations and carry out the absolute precise orbit determination (POD) with single-satellite ambiguity fixed, respectively. The result shows that a three-dimensional (3D) POD consistency of 1.48 cm (RMS) between them is reached. Then, the baseline products are obtained based on GPS and BDS-3 observations, respectively. The PBD of GPS-based is assessed via internal consistency checks and external baseline validations, Internally, the overlap comparison is sub-millimeter. Externally, comparisons with external agency is 1.36 mm in 3D. Taking the baseline results based on GPS as a reference, the difference shows that a consistency of PBD result based on BDS-3 is 0.91 mm in 3D. Finally, we perform the GPS + BDS-3 multi-GNSS data fusion for PBD experiment. The result shows that combining multi-GNSS data can not only increase the position precision and obtain a higher overlapping accuracy, but also improve the internal consistency of baseline products.
The precise baseline determination (PBD) is a crucial technique for spaceborne Interferometric Synthetic Aperture Radar (InSAR) formation-flying satellites to successfully carry out scientific missions. The Chinese InSAR formation T-A and T-B satellites are equipped with the multi-GNSS receiver that can track Global Positioning System (GPS) and BeiDou satellite navigation System (BDS-3) signals for PBD. First, we evaluate the data quality of spaceborne GPS and BDS-3 observations and carry out the absolute precise orbit determination (POD) with single-satellite ambiguity fixed, respectively. The result shows that a three-dimensional (3D) POD consistency of 1.48 cm (RMS) between them is reached. Then, the baseline products are obtained based on GPS and BDS-3 observations, respectively. The PBD of GPS-based is assessed via internal consistency checks and external baseline validations, Internally, the overlap comparison is sub-millimeter. Externally, comparisons with external agency is 1.36 mm in 3D. Taking the baseline results based on GPS as a reference, the difference shows that a consistency of PBD result based on BDS-3 is 0.91 mm in 3D. Finally, we perform the GPS + BDS-3 multi-GNSS data fusion for PBD experiment. The result shows that combining multi-GNSS data can not only increase the position precision and obtain a higher overlapping accuracy, but also improve the internal consistency of baseline products.
摘要：
The classical Haddock conjecture is extended to a kind of non-autonomous neutral functional differential equations (NFDEs) incorporating time-varying delays in this paper. By using the Dini derivative theory and inequality analyses, without requiring the strictly monotonically increasing property of the delay feedback function, it is demonstrated that every solution of the considered NFDEs is bounded and converges to a constant, which fully refines and generalizes the existing findings.
The classical Haddock conjecture is extended to a kind of non-autonomous neutral functional differential equations (NFDEs) incorporating time-varying delays in this paper. By using the Dini derivative theory and inequality analyses, without requiring the strictly monotonically increasing property of the delay feedback function, it is demonstrated that every solution of the considered NFDEs is bounded and converges to a constant, which fully refines and generalizes the existing findings.
摘要：
In Granular-ball Computing (GbC), the radius of a granular-ball is usually defined as the maximum or average distance from all enclosed objects to the center. However, both methods face challenges in building a high-quality family of granular-balls for enhanced classification performance. The former often results in overlaps between heterogeneous granular-balls, and the latter may fail to cover all objects. This paper presents an effective way to define the radius with adaptive granularity tuning and explores the subsequent application of the constructed granular-balls in classifications. Specifically, we introduce the concept of generalized granular-ball, where the center and radius are calculated with weight factors. The general granular-balls are further enhanced through two steps. The first step removes their overlaps through the concepts of heterogeneous neighborhood and de-overlapping parameter, reducing the granular-balls to be tangent or separate to each other. The second step further refines the radii of the tangent granular-balls by referencing the best granular-ball. Algorithms are developed to generate the granular-balls with dynamic radius adjustments and to build the subsequent classifier. Finally, experimental results on nine UCI datasets demonstrate the effectiveness and efficiency of our approach.
