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时空特征变分学习的交通流预测模型

控制理论与应用 2025年第1期42卷 158-166页

作者：欧阳毅汤文燕邵泳博黎晏伶浙江工商大学管理工程与电子商务学院浙江杭州310018

交通流量时空预测是智能交通系统的关键任务.针对城市交通流序列的非线性和多模态特性,本文提出了一种基于时空特征融合的变分学习模型(ST-FVAE),采用局部时空特征融合和全局特征融合两个阶段对具有图空间拓扑特性的交通流数据进行预测... 详细信息

交通流量时空预测是智能交通系统的关键任务.针对城市交通流序列的非线性和多模态特性,本文提出了一种基于时空特征融合的变分学习模型(ST-FVAE),采用局部时空特征融合和全局特征融合两个阶段对具有图空间拓扑特性的交通流数据进行预测.局部特征融合模块由时间卷积残差单元和图卷积神经网络(GCN)构成,提取交通节点的局部时间特征信息,并利用GCN将空间拓扑信息嵌入局部时间特征信息中.通过基于局部时空图特征融合的变分自编码器交通流预测模型,学习全局时空相关性特征.在全局时空特征融合变分自编码器的学习过程中,为使Q分布能够逼近实际数据P分布,通过最大化似然函数的变分推断证据下界(ELbo)使得两个分布之间的KL散度最小化,提出了计算分布期望的KL差异构造训练损失函数的方法,进一步提高预测准确率.通过对交通流数据集和交通速度数据集的预测实验结果表明:本文提出的方法在交通流量和速度的预测方面都具有较好的预测特性,对于30 min和60 min的预测鲁棒性更好.

关键词：交通流预测时空融合变分自编码器图卷积

On the rate of convergence of two generalized Bernstein type operators

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Applied Mathematics(A Journal of Chinese Universities) 2020年第3期35卷 321-331页

作者： LIAN bo-yong CAI Qing-bo Department of Mathematics Yang-En UniversityQuanzhou 362014China School of Mathematics and Computer Science Quanzhou Normal UniversityQuanzhou 362000China

In this paper,we introduce the Bézier variant of two new families of generalized Bernstein type *** establish a direct approximation by means of the Ditzian-Totik modulus of smoothness and a global approximation theorem in terms of second order modulus of *** means of construction of suitable functions and the method of bojanic and Cheng,we give the rate of convergence for absolutely continuous functions having a derivative equivalent to a bounded variation function.

关键词： Bernstein operators modulus of smoothness rate of convergence bounded variation

Reduced spin-down rate of PSR J0738–4042 explained as due to an asteroid disruption event

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Research in Astronomy and Astrophysics 2016年第5期16卷 41-46页

作者： yong-bo Yu yong-Feng Huang Department of Astronomy Nanjing UniversityNanjing 210046China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 2 1 0046China

Long term observations by Brook et al. reveal that the derivative of rotational frequency of PSR J0738-4042 changed abruptly in 2005. Originally, the spin-down rate was relatively stable, with the rotational frequency derivative being - 1.14 x 10-14 s-2. After September 2005, the derivative began to rise. About 1000 days later, it arrived at another relatively stable value of about -0.98 x 10-24 s-2, indicating that the pulsar is spinning-down relatively slowly. To explain the observed change in spin-down rate, we resort to an asteroid disrupted by PSR J0738-4042. In our model, the orbital angular momentum of the asteroid is assumed to be parallel to that of the rotating pulsar, so that the pronounced reduction in the spin-down rate can be naturally explained as due to the transfer of angular momentum from the disrupted material to the central pulsar. The derived magnetospheric radius is about 7.0 x 109 cm, which is smaller than the tidal disruption radius （8.7 x 10^10cm）. Our model is self-consistent. It is shown that the variability in the spin-down rate of PSR J0738-4042 can be quantitatively accounted for by accretion from the asteroid disrupted by the central pulsar.

关键词： stars: neutron -- planet-star interactions -- pulsars: individual (PSR J0738-4042)

A two-step energy injection explanation for the rebrightenings of the multi-band afterglow of GRB 081029

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Research in Astronomy and Astrophysics 2013年第6期13卷 662-670页

作者： yong-bo Yu yong-Feng Huang Department of Astronomy Nanjing University Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education

The afterglow of GRB 081029 showed unusual behavior, with a signifi- cant rebrightening being observed at the optical wavelength at about 3000 s after the burst. One possible explanation is that the rebrightening resulted from an energy in- jection. Here we present a detailed numerical study of the energy injection process and interpret the X-ray and optical afterglow light curves of GRB 081029. In our model, we have assumed two periods of energy injection, each with a constant injec- tion power. One injection starts at 2.8 × 10^3 s and lasts for about 2500 s, with a power of 7.0 × 10^47 erg s-1. This energy injection mainly accounts for the rapid rebrighten- ing at about 3000 s. The other injection starts at 8.0 × 10^3 s and lasts for about 5000 s. The injection power is 3.5 × 10^47 erg s-1. This energy injection can help to explain the slight rebrightening at about 10 000 s. It is shown that the observed optical after- glow, especially the marked rebrightening at about 3000 s, can be reproduced well. In the X-ray band, the predicted amplitude of the rebrightening is much shallower, which is also consistent with the observed X-ray afterglow light curve. It is argued that the two periods of energy injection can be produced by clumpy materials falling onto the central compact object of the burster, which leads to an enhancement of accretion and gives rise to a strong temporary outflow.

关键词： gamma-rays: bursts -- ISM: jets and outflows -- individual:GRB 081029

Pressure characteristics of landslide-generated impulse waves

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Journal of Mountain Science 2019年第8期16卷 1774-1787页

作者： TAN Jian-min HUANG bo-lin ZHAO yong-bo Wuhan Center of China Geological Survey WuhanChina433002 Hubei Key laboratory of Disaster Prevention and Mitigation China Three Gorges UniversityYichangChina443000

The destructiveness of impulse waves generated by landslides(IWL) originates from the wave’s movement and load, wherein the impulse wave’s load is the major cause of sub-aerial building damage and casualties. In this study, an experiment involving 16 groups of physical tests for the wave pressure generated by a landslide was designed, consisting of 4 sets of IWL and 4 opposite bank slope angles. A high-frequency strain system was used to measure the total pressure of the impulse wave in a water tank. The tests showed that the dynamic pressure caused by the IWL can be divided into two types: impact pressure generated by the jetflow and the pulsating pressure caused by the wave. Under the same impulse wave conditions, the maximum run-up becomes smaller as the opposite bank’s slope angle increases, and the jetflow maximum impact pressure experienced by the opposite bank increases, while the maximum pulsating pressure caused by the impulse wave is slightly decreased. Different from previous studies, the spatial maximum pressure distributions of the wave generated by landslide were concluded that the position of the maximum pulsating pressure appears adjacent to the still water surface, and the overall spatial distribution pattern of maximum wave pressure is presented as an inclined 'M' ***, this study is the first to quantitatively analyzed that impact pressure has a very short action time, is even 7 times of the pulse pressure value, and there is a simple mathematical linear relationship between the two. Currently, some wave-load formulas for wind waves and tides are not applicable to calculating the loads of IWL. Research on the load of IWL will explain the hazard of impulse wave very clearly, and will greatly contribute to hazard prevention, mitigation and risk assessment work associated with IWL.

关键词： Landslide Impulse wave Wave pressure Impact pressure Pulsating pressure Pressure distribution

Coordination bonds reinforcing mechanical strength of silicon anode to improve the electrochemical stability

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Rare Metals 2024年第11期43卷 5690-5700页

作者： Jin-Huan Li Hong-Qiang Xu Min Wu Quan Du yong-bo Kuang bo Yin Hai-yong He Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 101400China Chemistry and Chemical Engineering College Gannan Normal UniversityGanzhou 341000China

The severe volumetric expansion and poor conductivity of silicon when used as anode in lithium-ion batteries present challenges in maintaining the stability of electrochemical ***,the binding between silicon nanoparticles and carbon nanotubes(CNTs)is achieved by the utilization of sodium alginate(S A),which is then strengthened by the coordination between Ca^(2+)and the carboxyl group(-COO^(-))of SA,resulting in a stable conductive network with ionic transport *** consolidated binding relationship enables silicon-based anode material to possess high mechanical strength and strong deformation resistance,preventing the separation of silicon from CNTs ***,this silicon-based anode material demonstrates a discharge specific capacity of811 mAh·g^(-1)after 100 cycles at a current density of 1 A·g^(-1),and exhibits high rate performance,with a discharge specific capacity of 1612 mAh·g^(-1)at 2 A·g^(-1).

关键词： Lithium-ion batteries Silicon Mechanical strength Chemical coordination Cycle stability

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梯级电站调峰驱动的河道洪水波传播特征分析

长江科学院院报 2025年第2期42卷 91-99页

作者：白治朋黄建平刘新健刘新波文勇波赵新益栾华龙杨忠勇中国长江电力股份有限公司武汉430014 重庆渝方建筑工程设计有限公司重庆400020 重庆市建筑科学研究院有限公司重庆400042 长江科学院河流研究所武汉430010 三峡大学水利与环境学院湖北宜昌443002

基于三峡和葛洲坝电站2018年实测水位、流量数据和一维解析模型,重点讨论了梯级电站调峰驱动的洪水波在两坝间河道的传播过程。在三峡和葛洲坝同时进行日调峰的背景下,2个电站的出库流量均呈显著的日波动和半日波动现象,两电站的流量日... 详细信息

基于三峡和葛洲坝电站2018年实测水位、流量数据和一维解析模型,重点讨论了梯级电站调峰驱动的洪水波在两坝间河道的传播过程。在三峡和葛洲坝同时进行日调峰的背景下,2个电站的出库流量均呈显著的日波动和半日波动现象,两电站的流量日波动幅度平均分别在1500~2000 m^(3)/s和1200~1500 m^(3)/s之间,黄陵庙和南津关两个水位站的水位日波动幅度均在0.5~0.8 m之间。基于一维解析模型能够很好地模拟和再现两坝间河道的水位和流量波动过程。模型模拟结果分析表明,两坝间河道洪水波以周期为1.2 h的高频驻波进行传播,驻波的最大水位和流量振幅分别约为2.1 cm和210 m^(3)/s。该洪水波是由两个电站调峰流量共同驱动和叠加生成的,下游葛洲坝电站调峰时间对河道洪水波有显著影响,若将调峰时间由现行的0.6 h调整到1.2 h,洪水波振幅将显著增强。河道底摩擦因数对洪水波生成时的波高影响较小,但会影响洪水波在传播过程中的衰减速度。

关键词：电站调峰洪水波解析模型驻波波能衰减

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Security Analysis of a Block Encryption Algorithm Based on Dynamic Sequences of Multiple Chaotic Systems

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Chinese Physics Letters 2011年第1期28卷 39-42页

作者： DU Mao-Kang HE bo WANG yong Key Laboratory of Electronic Commerce and Logistics Chongqing University of Posts and Telecommunications Chongqing 400065

Recently, the cryptosystem based on chaos has attracted much attention. Wang and Yu （Commun. Nonlin. Sci. Numer. Simulat. 14（2009）574） proposed a block encryption algorithm based on dynamic sequences of multiple chaotic systems. We analyze the potential flaws in the algorithm. Then, a chosen-plaintext attack is presented. Some remedial measures are suggested to avoid the flaws effectively. Furthermore, an improved encryption algorithm is proposed to resist the attacks＂ and to keep all the merits of the original cryptosystem.

关键词： Computational physics Quantum information and quantum mechanics Statistical physics and nonlinear systems

Preparation of calcium carbonate particles coated with titanium dioxide

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International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 592-597页

作者： Hai Lin Ying-bo Dong Le-yong Jiang School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China

The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was studied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanoehemieal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5：3.5. The mass ratios of two different types of titanium dioxide （anatase to rutile） and grinding media to grinded materials were 8：2 and 4：1 respectively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification. The hiding power and oil absorption of this new material were 29.12 g/m^2 and 23.30%, respectively. The results show that the modification is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be improved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.

关键词： calcium carbonate mechano-chemical process titanium dioxide film hydroxylation