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MSADCN:Multi-Scale Attentional Densely Connected Network for Automated Bone Age Assessment

Computers, Materials & Continua 2024年第2期78卷 2225-2243页

作者： Yanjun Yu Lei Yu Huiqi Wang Haodong Zheng Yi Deng college of Computer and Information Science Chongqing Normal UniversityChongqing401331China college of Mathematics and statistics Chongqing UniversityChongqing401331China

Bone age assessment(BAA)helps doctors determine how a child’s bones grow and develop in clinical medicine.Traditional BAA methods rely on clinician expertise,leading to time-consuming predictions and inaccurate results.Most deep learning-based BAA methods feed the extracted critical points of images into the network by providing additional annotations.This operation is costly and subjective.To address these problems,we propose a multi-scale attentional densely connected network(MSADCN)in this *** constructs a multi-scale dense connectivity mechanism,which can avoid overfitting,obtain the local features effectively and prevent gradient vanishing even in limited training data.First,MSADCN designs multi-scale structures in the densely connected network to extract fine-grained features at different scales.Then,coordinate attention is embedded to focus on critical features and automatically locate the regions of interest(ROI)without additional annotation.In addition,to improve the model’s generalization,transfer learning is applied to train the proposed MSADCN on the public dataset IMDB-WIKI,and the obtained pre-trained weights are loaded onto the Radiological Society of North America(RSNA)dataset.Finally,label distribution learning(LDL)and expectation regression techniques are introduced into our model to exploit the correlation between hand bone images of different ages,which can obtain stable age estimates.Extensive experiments confirm that our model can converge more efficiently and obtain a mean absolute error(MAE)of 4.64 months,outperforming some state-of-the-art BAA methods.

关键词： Bone age assessment deep learning attentional densely connected network muti-scale

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THE LONG TIME BEHAVIOR OF THE FRACTIONAL ORNSTEIN-UHLENBECK PROCESS WITH LINEAR SELF-REPELLING DRIFT

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Acta Mathematica Scientia 2024年第2期44卷 671-685页

作者：夏晓宇闫理坦杨晴 college of Information Science and Technology Donghua UniversityShanghai201620China Department of statistics College of ScienceDonghua UniversityShanghai201620China

Let B^(H) be a fractional Brownian motion with Hurst index 1/2≤H<1.In this paper,we consider the equation(called the Ornstein-Uhlenbeck process with a linear self-repelling drift)dX_(t)^(H)=dB_(t)^(H)+σ X_(t)^(H)dt+vdt-θ(∫_(0)^(t)(X_(t)^(H)-X_(s)^(H))ds)dt,whereθ<0,σ,v∈ℝ.The process is an analogue of self-attracting diffusion(Cranston,Le Jan.Math Ann,1995,303:87–93).Our main aim is to study the large time behaviors of the process.We show that the solution X^(H)diverges to infinity as t tends to infinity,and obtain the speed at which the process X^(H)diverges to infinity.

关键词： fractional Brownian motion stochastic difference equations rate of convergence asymptotic

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Blockchain-Based Certificateless Bidirectional Authenticated Searchable Encryption Scheme in Cloud Email System

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 3287-3310页

作者： Yanzhong Sun Xiaoni Du Shufen Niu Xiaodong Yang college of Mathematics and statistics Northwest Normal UniversityLanzhou730070China college of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China

Traditional email systems can only achieve one-way communication,which means only the receiver is allowed to search for emails on the email server.In this paper,we propose a blockchain-based certificateless bidirectional authenticated searchable encryption model for a cloud email system named certificateless authenticated bidirectional searchable encryption(CL-BSE)by combining the storage function of cloud server with the communication function of email server.In the new model,not only can the data receiver search for the relevant content by generating its own trapdoor,but the data owner also can retrieve the content in the same way.Meanwhile,there are dual authentication functions in our model.First,during encryption,the data owner uses the private key to authenticate their identity,ensuring that only legal owner can generate the keyword ciphertext.Second,the blockchain verifies the data owner’s identity by the received ciphertext,allowing only authorized members to store their data in the server and avoiding unnecessary storage space consumption.We obtain a formal definition of CL-BSE and formulate a specific scheme from the new system model.Then the security of the scheme is analyzed based on the formalized security model.The results demonstrate that the scheme achieves multikeyword ciphertext indistinguishability andmulti-keyword trapdoor privacy against any adversary simultaneously.In addition,performance evaluation shows that the new scheme has higher computational and communication efficiency by comparing it with some existing ones.

关键词： Cloud email system authenticated searchable encryption blockchain-based designated server test multi-trapdoor privacy multi-ciphertext indistinguishability

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Quasi-shadowing for Z^(d)-actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1563-1580页

作者： Juan PAN Xian Kun REN Yun Hua ZHOU School of Mathematics and statistics Chongqing Technology and Business UniversityChongqing 400067P.R.China college of Mathematics and statistics Chongqing UniversityChongqing 401331P.R.China

A diffeomorphism is non-uniformly partially hyperbolic if it preserves an ergodic measure with at least one zero Lyapunov exponent.We prove that a C^(1)-smooth Z^(d)-action has the quasishadowing property if one of th... 详细信息

关键词： Quasi-shadowing Z^(d)-action non-uniformly partially hyperbolic ergodic measure

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Pricing Guaranteed Minimum Death Benefits with Dollar Cost Averaging Under Time-changed Le′vy Models

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Acta Mathematicae Applicatae Sinica 2024年

作者： Jia-ming WANG Mei-qiao AI Zhi-min ZHANG college of Mathematics and statistics Chongqing University

In this paper, we propose an efficient and accurate method for pricing Guaranteed Minimum Death Benefit (GMDB) under time-changed Le′vy processes. Suppose that the GMDB payoff depends on a dollar cost averaging (DCA) style periodic investment, and the activity rate process in stochastic time change is modeled by a square-root process. We develop a recursive method to derive the closed form valuation formula by using the frame duality projection method. Numerical examples are reported for demonstrating the effectiveness of our approach and illustrating the interplay between contract parameters and the valuation.

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Incentive Feedback Stackelberg Strategy in Mean-Field Type Stochastic Difference Games

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Journal of Systems Science & Complexity 2024年第4期37卷 1425-1445页

作者： GAO Wenhui LIN Yaning ZHANG Weihai School of Mathematics and statistics Shandong University of Technology college of Electrical Engineering and Automation Shandong University of Science and Technology

This paper designs an incentive Stackelberg strategy for the discrete-time stochastic systems with mean-field terms. Sufficient conditions for the existence of such a design are suggested.Moreover, the incentive strategy is obtained as a feedback form including the deviation of the state and its mathematical expectation. Also, the stability analysis is involved. It is found that the stability can be guaranteed by the follower. In addition, the specific algorithm is proposed and its effectiveness is checked by two examples.

关键词： Discrete-time mean-field stochastic systems incentive strategy Stackelberg game teamoptimal solution

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Bilinear Strongly Singular Calderón-Zygmund Operators and Their Commutators on Non-Homogeneous Generalized Morrey Spaces

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Journal of Mathematical Research with Applications 2024年第1期44卷 43-62页

作者： Guanghui LU Miaomiao WANG college of Mathematics and statistics Northwest Normal University

The main goal of this paper is to establish the boundedness of bilinear strongly singular operator■ and its commutator■b1,b2on generalized Morrey spaces Mpu(μ) over nonhomogeneous metric measure spaces.Under assumption that the Lebesgue measurable functions u,u1and u2belong to Wτfor τ∈(0,2),and u1u2=u.The authors prove that■ is bounded from product spaces Mp1u1(μ)×Mp2u2(μ) into spaces Mpu(μ),where 1/p=1/p1+1/p2with 1

关键词： non-homogeneous metric measure space bilinear strongly singular Calderon-Zygmund operator commutator space RBMO(μ) generalized Morrey space

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Random Exponential Attractor for Stochastic Non-autonomous Suspension Bridge Equation with Linear Multiplicative White Noise

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Journal of Mathematical Research with Applications 2024年第1期44卷 81-112页

作者： Ling XU Runjie LIU Xue BAI college of Mathematics and statistics Northwest Normal University

In this paper, we mainly consider the long-time behavior of stochastic non-autonomous suspension bridge equation by linear multiplicative white noise with small coefficient. First step,the well-posedness for the cocycle associated with the considered system is established. Second step, the existence of random attractor for the system is investigated. Third step, the upper semicontinuity of random attractor is also provided when the coefficient of random term approaches zero. Fourth step, we prove the regularity of random attractor in a higher regular space by the“iteration” method. Finally, we give the existence of a random exponential attractor for the considered system, which implies the finiteness of fractal dimension of random attractor.

关键词： stochastic non-autonomous suspension bridge equation multiplicative white noise random attractor fractal dimension random exponential attractor

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The dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria

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International Journal of Biomathematics 2024年第3期17卷 265-287页

作者： Xing-Xing Yang Guo-Bao Zhang Ge Tian college of Mathematics and statistics Northwest Normal University Lanzhou Gansu 730070P.R.China

In this paper,we mainly investigate the dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria.We first establish the existence of spreading speed,and show that the spreading speed coincides with the minimal wave speed of traveling wavefronts.Moreover,a lower bound estimate of the spreading speed is given.Then,we prove that the traveling wavefronts with large speeds are globally exponentially stable,when the initial perturbation around the traveling wavefronts decays exponentially asχ→-∞,but the initial perturbation can be arbitrarily large in other locations.The adopted methods are the weighted energy and the squeezing technique.

关键词： Host tissue degradation bacterial infection traveling wavefronts minimal wave speed stability

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Multicolored Bipartite Ramsey Numbers of Large Cycles

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 347-357页

作者： Shao-qiang LIU Yue-jian PENG college of Mathematics and statistics Hanshan Normal UniversityChaozhou 521041China School of Mathematics Hunan UniversityChangsha 410082China

For an integer r≥2 and bipartite graphs Hi,where 1≤i≤r,the bipartite Ramsey number br(H1,H2,…,Hr)is the minimum integer N such that any r-edge coloring of the complete bipartite graph KN;N contains a monochromatic subgraph isomorphic to Hi in color i for some 1≤i≤r.We show that if r≥3;α1,α2>0,αj+2≥[(j+2)!-1]Σi=1^(j+1)α1 for j=1,2…r-2,then br(C2[α1n],C2[α2n],…,C2[αrn]=(Σ=j=1^(r)a j+o(1))n.

关键词： ramsey number bipartite ramsey number regularity lemma

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