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CLEAN:Frequent Pattern-Based Trajectory Compression and Computation on Road Networks

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China Communications 2020年第5期17卷 119-136页

作者： Peng Zhao Qinpei Zhao Chenxi Zhang gong su Qi Zhang Weixiong Rao Tongji University Shanghai 201804China IBM T.J.Watson Research Center New York 10598USA

The volume of trajectory data has become tremendously huge in recent years. How to effectively and efficiently maintain and compute such trajectory data has become a challenging task. In this paper, we propose a trajectory spatial and temporal compression framework, namely CLEAN. The key of spatial compression is to mine meaningful trajectory frequent patterns on road network. By treating the mined patterns as dictionary items, the long trajectories have the chance to be encoded by shorter paths, thus leading to smaller space cost. And an error-bounded temporal compression is carefully designed on top of the identified spatial patterns for much low space cost. Meanwhile, the patterns are also utilized to improve the performance of two trajectory applications, range query and clustering, without decompression overhead. Extensive experiments on real trajectory datasets validate that CLEAN significantly outperforms existing state-of-art approaches in terms of spatial-temporal compression and trajectory applications.

关键词： trajectory compression pattern mining spatial-temporal compressions range query clustering

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基于邻域表面特征的隐式神经表示方法

计算机工程与设计 2024年第7期45卷 2111-2118页

作者：于楚飞苏工兵王晶袁梦曾文豪武汉纺织大学机械工程与自动化学院湖北武汉430200 武汉纺织大学湖北省数字化纺织装备重点实验室湖北武汉430200

隐式神经表示能够实现任意分辨率下的表面重建。现有方法仅使用了坐标信息,未考虑到其邻域表面上的特征对局部形状的贡献,因此难以精确恢复表面上复杂的纹理和拓扑。为此,提出一种采用编码-解码策略的改进模型,提高表面重建的精度。编... 详细信息

隐式神经表示能够实现任意分辨率下的表面重建。现有方法仅使用了坐标信息,未考虑到其邻域表面上的特征对局部形状的贡献,因此难以精确恢复表面上复杂的纹理和拓扑。为此,提出一种采用编码-解码策略的改进模型,提高表面重建的精度。编码器获取坐标在邻域表面上的特征编码和其在高维空间下的映射编码。在解码器中应用损失自适应加权策略,提高编码信息的利用率。实验结果表明,较现有方法显著提高了重建结果的精度,其重叠度和F-score分别提高了1.458%和1.46%,平均倒角距离降低了0.08。

关键词：表面重建隐式神经表示符号距离函数点云多层感知机傅里叶变换编码器

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泰州市海陵区行道树应用现状调查与分析

安徽农业科学 2024年第10期52卷 140-143页

作者：曲良谱吴红龚苏文江苏农牧科技职业学院园林园艺学院江苏泰州225300 泰州高教开元房地产开发有限公司江苏泰州225300

应用抽样调查法调查了泰州市海陵区30条主干道及次干道行道树树种的应用现状,分析了行道树的种类、数量和径级结构。结果表明:海陵区行道树共计20科33属,共计35种63757株;其中落叶树种和常绿树种比例为2.5∶1;总体上看,行道树规格明显偏... 详细信息

应用抽样调查法调查了泰州市海陵区30条主干道及次干道行道树树种的应用现状,分析了行道树的种类、数量和径级结构。结果表明:海陵区行道树共计20科33属,共计35种63757株;其中落叶树种和常绿树种比例为2.5∶1;总体上看,行道树规格明显偏小,胸径级别处于Ⅰ级(<15 cm)的最多,占行道树总量的39.53%;处于Ⅱ级(15~<20 cm)的次之,占34.63%;占第3位的是处于Ⅲ级(20~<25 cm),占15.28%;IV级(≥25 cm)的数量最少,仅占10.56%。存在种类单一,树种选择盲目及树种养护管理不到位等问题,并提出了优化建议。

关键词：泰州行道树树种类型结构分析应用现状

Design methodology of a mini-missile considering flight performance and guidance precision

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Journal of Systems Engineering and Electronics 2024年第1期35卷 195-210页

作者： ZHANG Licong gong Chunlin su Hua ANDREA Da Ronch Shaanxi Aerospace Flight Vehicle Design Key Laboratory School of AstronauticsNorthwestern Polytechnical UniversityXi’an 710072China Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171BJUnited Kingdom

The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.

关键词： mini-missiles(MMs) guidance navigation and control(GNC)system multi-objective optimization multidisciplinary design optimization(MDO) flight performance guidance precision

Delay-dependent robust H_∞control of convex polyhedral uncertain fuzzy systems

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1191-1198页

作者： gong Cheng su Baoku Dept. of Control Theory and Control Engeering Harbin Inst. of Technology Harbin 150001 P. R. China

The robust H∞ control problem for a class of uncertain Takagi-sugeno fuzzy systems with timevarying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent Lyapunov functional method, a new delay-dependent robust H∞ fuzzy controller, which depends on the size of the delays and the derivative of the delays, is presented in term of linear matrix inequalities （LMIs）. For all admissible uncertainties and delays, the controller guarantees not only the asymptotic stability of the system but also the prescribed H∞ attenuation level. In addition, the effectiveness of the proposed design method is demonstrated by a numerical example.

关键词： robust H∞ control delay-dependent polyhedral uncertainty fuzzy systems

Fundamentals and progress of the manifold method based on independent covers

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Science China(Technological Sciences) 2024年第4期67卷 966-991页

作者： su HaiDong LIN ShaoZhong XIE ZhiQiang gong YaQi QI YongFeng Material and Engineering Structure Department Yangtze River Scientific Research InstituteWuhan 430010China Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources Wuhan 430010China

Aiming to solve mesh generation,computational stability,accuracy control,and other problems encountered with existing numerical methods,such as the finite element method and the finite volume method,a new numerical computational method for continuum mechanics,namely the manifold method based on independent covers(MMIC),is proposed based on the concept of mathematical manifolds,to form partitioned series solutions of partial differential equations.As partitions,the cover meshes have the characteristics of arbitrary shape,arbitrary connection,and arbitrary refinement.They are expected to fundamentally solve the mesh generation problem and can also simulate the precise geometric boundaries of the CAD model and strictly impose boundary conditions.In the selection of series solutions,local analytical solutions(such as series solutions at crack tips and series solutions in infinite domains)or proper forms of complete series can be used to reflect the local or global characteristics of the physical field to accelerate convergence.Various applications are presented.A new method of beam,plate,and shell analysis is proposed.The deformation characteristics of beams,plates,and shells are simulated with polynomial series of suitable forms,and the analysis of curved beams and shells with accurate geometric representation is realized.For the static elastic analysis of two-dimensional structures,a mesh splitting algorithm is proposed,and h-p version adaptive analysis is carried out with error estimation.Thus,automatic computation integrated with CAD is attempted.Adaptive analysis is also attempted for the solution of differential equations of fluids.For the one-dimensional convection-diffusion equation and Burgers equation,calculation results with high precision are obtained in strong convection and shock wave simulations,avoiding nonphysical oscillations.And solving the two-dimensional incompressible Navier-Stokes equation is also attempted.The series solution formula is used to obtain the physical quantity of interest of the m

关键词： series solutions mesh generation adaptive analysis fixed meshes numerical manifold method

Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of Materials Science & Technology 2024年第5期172卷 71-82页

作者： Xiang su Yuan Lei Yang Chen Hongjie Qu Zhixiang Qi gong Zheng Xu Liu Henggao Xiang Guang Chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy conservation.However,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening phases.Here,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum alloys.The enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one time.The significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T phase.The thermostable T phase effectively strengthens the matrix by in-hibiting dislocation motion.Meanwhile,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high temperatures.This finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

Parity-dependent skin effects and topological properties in the multilayer nonreciprocal su−Schrieffer−Heeger structures

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Frontiers of physics 2024年第3期19卷 115-133页

作者： Jia-Rui Li Cui Jiang Han su Di Qi Lian-Lian Zhang Wei-Jiang gong College of Sciences Northeastern UniversityShenyang 110819China Basic Department Shenyang Institute of EngineeringShenyang 110136China

We concentrate on the skin effects and topological properties in the multilayer non-Hermitian su−Schrieffer−Heeger (SSH) structure, by taking into account the nonreciprocal couplings between the different sublattices in the unit cells. Following the detailed demonstration of the theoretical method, we find that in this system, the skin effects and topological phase transitions induced by nonreciprocal couplings display the apparent parity effect, following the increase of the layer number of this SSH structure. On the one hand, the skin effect is determined by the parity of the layer number of this SSH system, as well as the parity of the band index of the bulk states. On the other hand, for the topological edge modes, such an interesting parity effect can also be observed clearly. Next, when the parameter disorders are taken into account, the zero-energy edge modes in the odd-layer structures tend to be more robust, whereas the other edge modes are easy to be destroyed. In view of these results, it can be ascertained that the findings in this work promote to understand the influences of nonreciprocal couplings on the skin effects and topological properties in the multilayer SSH lattices.

关键词： multilayer SSH lattice nonreciprocal couplings band structure skin effect

Application of artificial intelligence in diagnosis of pulmonary tuberculosis

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Chinese Medical Journal 2024年第5期137卷 559-561页

作者： Jingli Du Yue su Juan Qiao Shang Gao Enjun Dong Ruilan Wang Yanhui Nie Jing Ji Zhendong Wang Jianqin Liang Wenping gong Tuberculosis Control Team Senior Department of TuberculosisThe Eighth Medical Center of PLA General HospitalBeijing 100091China Department of Computer Science and Technology College of Management Science and EngineeringCapital University of Economics and BusinessBeijing 100071China The Second Ward of Tuberculosis Department Senior Department of TuberculosisThe Eighth Medical Center of PLA General HospitalBeijing 100091China Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment Senior Department of TuberculosisThe Eighth Medical Center of PLA General HospitalBeijing 100091China

Tuberculosis(TB)is an infectious disease caused by Mycobacterium tuberculosis.Although the diagnostic technology of pulmonary tuberculosis(PTB)has advanced,accurate and differential diagnoses of PTB are still challenging.In recent years,the rapid development of artificial intelligence(AI)and its wide application in the medical field have provided new opportunities for diagnosing and treating TB and PTB.The machine learning model of AI has not only helped physicians improve diagnostic accuracy,but also enabled them to make early preventive diagnoses for individuals at increased risk of infection.Furthermore,AI can guide physicians to formulate targeted treatment strategies for PTB patients with different conditions.

关键词： tuberculosis diagnosis artificial