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Representation and Organization for Spatial Data in LBS

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Journal of Earth Science 2014年第3期25卷 544-549页

作者： yanhui wang Yue Li Key Lab of 3D Information Collection and Application of Ministry of Education Capital Normal University

Aiming at the special demand on SVG_based representation and organization for spatial data in location based services（LBS）, the research is made in this article on the conversion method from multiple formats to SVG format, and a harris_corner detector method is proposed and verified to evaluate the conversion result. Based on the above, an optimized compression arithmetic is proposed, which integrated the characteristic of code simplification and GZIP compression. The test shows that the techniques on conversion and compression are feasible, which means that SVG_based representation is suited for spatial data in LBS and the improved compression arithmetic is prior to the former.

关键词： location based services(LBS) scalable vector graphic(SVG) conversion method harris_corner detector optimized compression arithmetic.

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A SIMULATION METHOD FOR ANALYZING AND EVALUATING RAIL SYSTEM PERFORMANCE BASED ON SPEED PROFILE

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Journal of Systems Science and Systems Engineering 2018年第6期27卷 810-834页

作者： Hangfei Huang Keping Li yanhui wang State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing 100044 China

This paper presents and discusses a simulation method for analyzing and evaluating system performance on a rail line from the perspective of speed profile. Dynamic analysis for train motions is introduced, and a discrete time-operation graph is proposed to represent the relation between speed profile and energy consumption. Based on them, an analytical model is formulated to provide a quick insight into the system performance. The discrete-time simulation （DTS） method is then implemented to study the system in detail. Compared to the existing simulations, two innovations are included in the DTS：（1） the analytical lookup tables that can simplify the dynamic computation and, （2） the speed profile adjustment process that forecasts and avoids future conflicts based on practical constraints. The numerical results show that the DTS speed profile has advantages over existing methods. Finally, the DTS method is used to analyze and evaluate the system performance of the current timetable on Beijing Yizhuang Metro Line. The results suggest that the current timetable is not robust enough, and thus possible improvements are discussed at both scheduling and operating stages. The proposed method is verified to be effective and reliable for practical uses.

关键词： Simulation speed profile discrete graph dynamic analysis system evaluation

A Bionic Flexible-bodied Underwater Glider with Neutral Buoyancy

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Journal of Bionic Engineering 2021年第5期18卷 1073-1085页

作者： Yaqiang Zhu Yuhong Liu Shuxin wang Lianhong Zhang yanhui wang Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education School of Mechanical EngineeringTianjin UniversityTianjin 300350China The Joint Laboratory of Ocean Observing and Detection Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

The buoyancy of traditional Underwater Glider(UG)with a rigid hull is aff ected by the changing marine parameters,making it difficult for the vehicle to dive deeper with good motion *** the present work,the development of a novel UG for neutral buoyancy,which is equipped with a Flexible-Liquid-Rigid(FLR)composite hull,is *** innovative hull that imitates the buoyancy regulation mechanism of marine organisms is easily adaptable to the changing marine *** rigid part of the composite hull withstands hydrostatic pressure for inner function modules of the *** liquid of the composite hull mainly serves as a buoyancy compensation to mitigate the eff ect of buoyancy variation caused by the changing marine *** flexible covering provides a good hydrodynamic shape for the vehicle under the internal liquid *** buoyancy variation due to the composite hull compression as well as changes of seawater density and temperature was comprehensively considered in the design process and integrated to the dynamic *** addition,sea trials were performed to verify the motion characteristics of the proposed *** results reveal that the Flexible-bodied Underwater Glider(FUG)has a better gliding performance in practice.

关键词： Bio-inspired buoyancy regulation Flexible-bodied vehicle Composite hull Adaptable buoyancy compensation

Design,hydrodynamic analysis,and testing of a bioinspired controllable wing mechanism with multi-locomotion modes for hybrid-driven underwater gliders

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Science China(Technological Sciences) 2021年第12期64卷 2688-2708页

作者： SUN TongShuai wang yanhui YANG ShaoQiong wang Cheng ZHANG LianHong Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China Qingdao Pilot National Laboratory for Marine Science and Technology(QNLM) Qingdao 266237China

Hybrid-driven technology,which can improve the sailing performance of underwater gliders(UGs),has been successfully used in ocean ***,a hybrid-driven UG(HUG)with an added tail propeller is still unable to achieve backward and turning motion with a body length radius,and the hydrodynamic pitch moment acting on the HUG that is mainly caused by the fixed-wing makes it difficult to achieve high-precision attitude control during fixed-depth *** solve this problem,a two-degree-of-freedom bioinspired controllable wing mechanism(CWM)is proposed to improve the maneuverability and cruising ability of *** CWM can realize five motion modes:modifying the dihedral angle or anhedral angle,changing the frontal area of the wing,switching the wing from horizontal to be a vertical rudder,flapping the wing as propulsion,and rotating the wing as a vector ***,the design process of the CWM is provided,and hydrodynamic forces in each motion mode of three CWMs with different trailing edge sweepback angles(TESA)and attitude angles are analyzed through computational fluid dynamics *** relationship between hydrodynamics and the attitude angles or TESA of the CWM is ***,experiments are conducted to measure the hydrodynamics of the CWM when it is in a flapping wing mode and rotating the wing as a vector propeller,*** hydrodynamic forces obtained from the simulation are consistent with data measured by a force sensor,proving the credibility of the simulated ***,by applying the results of the hydrodynamic force in this study,the flapping trajectory of the wingtip is planned using the cubic spline interpolation ***,two underwater demo vehicles with a pair of CWMs are developed,and experiments are conducted in a water tank,further validating and demonstrating the feasibility of the proposed CWM.

关键词： controllable wing mechanism hybrid-driven underwater glider bioinspired design multi-locomotion modes

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An improved probabilistic relaxation method for matching multi-scale road networks

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International Journal of Digital Earth 2018年第6期11卷 635-655页

作者： Jianchen Zhang yanhui wang Wenji Zhao College of Resources Environment and Tourism Capital Normal UniversityBeijingPeople’s Republic of China D Information Collection and Application Key Lab of Education Ministry Capital Normal UniversityBeijingPeople’s Republic of China Beijing State key Laboratory Incubation Base of Urban Environmental Processes and Digital Simulation Capital Normal UniversityBeijingPeople’s Republic of China

Matching multi-scale road networks in the same area is the first step in merging two road networks or updating one based upon the *** quality of the merge or update depends greatly on the matching accuracy of the two road *** propose an improved probabilistic relaxation method,considering both local and global optimizations for matching multi-scale of road *** aim is to achieve local optimization,as well as to address the identification of the M:N matching pattern by means of inserting virtual nodes to achieve global optimization ***,by adding two attribute-related evaluation indicators,we developed four evaluation indicators to evaluate the matching accuracy,considering both geographic and attribute *** paper also provides instructions on how to identify the proper buffer threshold during matching *** experiments were conducted to compare the proposed method with the traditional *** results indicate that:(1)the overall matching accuracy of each evaluation indicator exceeds 90%;(2)the overall matching accuracy increases by 6–12%after an M:N matching pattern is added,and by 4–6%following the addition of topology indicators;and(3)the proper buffer threshold is about twice the average value of the closest distance from all nodes.

关键词： Improved probabilistic relaxation multi-scale road network matching topology constraint M:N matching pairs matching accuracy

Period Multiplication in a Continuous Time Series of Radio-Frequency DBDs at Atmospheric Pressure

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Communications in Computational Physics 2012年第4期11卷 1226-1235页

作者： Jiao Zhang yanhui wang Dezhen wang State Key Laboratory of Materials Modification by Laser Electronand Ion BeamsSchool of Physics and Optoelectronic TechnologyDalian University of TechnologyDalian 116024China

As a spatially extended dissipative system with strong nonlinearity,the radio-frequency(rf)dielectric-barrier discharges(DBDs)at atmospheric pressure possess complex spatiotemporal nonlinear *** this paper,the time-domain nonlinear behaviors of rf DBD in atmospheric argon are studied numerically by a onedimensional fluid *** results show that,under appropriate controlling parameters,the rf DBD can undergo a transition from single-period state to chaos through period doubling bifurcation with increasing discharge time,i.e.,the regular periodic oscillation and chaos can coexist in a long time series of the atmosphericpressure rf *** increasing applied voltage amplitude,the duration of the periodic oscillation reduces gradually and chaotic zone increases,and finally the whole discharge series becomes completely chaotic *** is different from conventional period doubling route to ***,the spatial characteristics of rf perioddoubling discharge and chaos,as well as the parameter range of various discharge behaviors occurring are also investigated in this paper.

关键词： Atmospheric radio-frequency discharge period-doubling bifurcation chaos

Design,Hydrodynamic Analysis,and Testing of a Bio-inspired Movable Bow Mechanism for the Hybrid-driven Underwater Glider

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Journal of Bionic Engineering 2023年第4期20卷 1493-1513页

作者： yanhui wang Yudong Guo Shaoqiong Yang Tongshuai Sun Xi wang Huihui Zhou Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin300072China The Joint Laboratory of Ocean Observing and Detection Laoshan LaboratoryQingdao266237China

Hybrid-driven Underwater Glider(HUG)is a new type of underwater vehicle which integrates the functions of an Autonomous Underwater Glider(AUG)and an Autonomous Unmanned Vehicle(AUV).Although HUG has the characteristics of long endurance distance,its maneuverability still has room to be *** work introduces a new movement form of the neck of the underwater creature into HUG and proposes a parallel mechanism to adjust the attitude angle and displacement of the HUG’s bow,which can improve the steering ***,the influence of bow movement and rotation on the hydrodynamic force and flow field of the whole machine is analyzed by using the Computational Fluid Dynamics(CFD)*** degree of freedom,attitude control range and movement amount of the Movable Bow Mechanism(MBM)are obtained,and then the design of MBM is completed based on these ***,the kinematic and dynamic models of MBM are established based on the closed vector method and the Lagrange equation,respectively,which are fully verified by comparing the results of simulation in Matlab and Adams software,then a Radial Basis Function(RBF)neural network adaptive sliding mode controller is designed to improve the dynamic response effect of the output parameters of ***,a prototype of MBM is manufactured and *** kinematic,dynamics model and controller are verified by experiments,which provides a basis for applying MBM in HUGs.

关键词： Underwater glider Movable bow mechanism Hydrodynamic simulation Steering maneuverability

Effect of Coiling Temperature on the Evolution of Texture in Ferritic Rolled Ti-IF Steel

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Journal of Materials Science & Technology 2007年第3期23卷 337-341页

作者： Zhaodong wang yanhui CUO Wenying XUE Xianghua LIU Cuodong wang The State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 China

The effect of coiling temperatures on the evolution of texture in Ti-IF steel during ferritic hot rolling, cold rolling and annealing was studied. It was found that texture evolution at high temperature coiling is absolutely different from that at low temperature one. The hot band texture includes a strong α-fiber as well as a weak γ-fiber after ferritic hot rolling and low temperature coiling. Both of them intensify after cold rolling and a γ-fiber with peak at {111}〈112〉 is the main texture of annealed samples. However, the main component of the hot band texture after high temperature coiling is v-fiber. After cold rolling, the intensity of γ texture reduces; α fiber （except {111}〈110〉 component） intensifies and a strong and well-proportioned γ-fiber forms in the annealed samples.

关键词： Ti-IF steel Ferritic hot rolling Coiling temperature Texture

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FGM-SPCL:Open-Set Recognition Network for Medical Images Based on Fine-Grained Data Mixture and Spatial Position Constraint Loss

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Chinese Journal of Electronics 2024年第4期33卷 1023-1033页

作者： Ruru ZHANG Haihong E Lifei YUAN yanhui wang Lifei wang Meina SONG School of Computer Science Beijing University of Posts and Telecommunications Engineering Research Center of Information Networks Ministry of Education Hebei Eye Hospital

The current intelligent auxiliary diagnosis models all follow the closed-set recognition setting. After the model is deployed online, the input data is often not completely controlled. Diagnosing an untrained disease as a known category would lead to serious medical malpractice. Therefore, realizing the open-set recognition is significant to the safe operation of the intelligent auxiliary diagnosis model. Currently, most open-set recognition models are studied for natural images, and it is very challenging to obtain clear and concise decision boundaries between known and unknown classes when applied to fine-grained medical images. We propose an open-set recognition network for medical images based on fine-grained data mixture and spatial position constraint loss(FGM-SPCL) in this *** the fine graininess of medical images and the diversity of unknown samples, we propose a fine-grained data mixture(FGM) method to simulate unknown data by performing a mixing operation on known data to expand the coverage of unknown data difficulty levels. In order to obtain a concise and clear decision boundary, we propose a spatial position constraint loss(SPCL) to control the position distribution of prototypes and samples in the feature space and maximize the distance between known classes and unknown classes. We validate on a private ophthalmic OCT dataset, and extensive experiments and analyses demonstrate that FGM-SPCL outperforms state-of-the-art models.

关键词： Analytical models Fine-grained image recognition Prototypes Aerospace electronics Spatial databases Robustness Data models