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Self-evident Automated Proving Based on point Geometry from the Perspective of Wu's Method Identity

Journal of Systems Science & Complexity 2019年第1期32卷 78-94页

作者： ZHANG Jingzhong PENG Xicheng CHEN Mao National Engineering Research Center for E-Learning Central China Normal University Institute of Computational Science and Technology Guangzhou University Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

The algebraic methods represented by Wu's method have made signi?cant breakthroughs in the ?eld of geometric theorem proving. Algebraic proofs usually involve large amounts of calculations, thus making it diffcult to understand intuitively. However, if the authors look at Wu's method from the perspective of identity, Wu's method can be understood easily and can be used to generate new geometric propositions. To make geometric reasoning simpler, more expressive, and richer in geometric meaning, the authors establish a geometric algebraic system(point geometry built on nearly 20 basic properties/formulas about operations on points) while maintaining the advantages of the coordinate method, vector method, and particle geometry method and avoiding their disadvantages. Geometric relations in the propositions and conclusions of a geometric problem are expressed as identical equations of vector polynomials according to point geometry. Thereafter, a proof method that maintains the essence of Wu's method is introduced to ?nd the relationships between these equations. A test on more than 400 geometry statements shows that the proposed proof method, which is based on identical equations of vector polynomials, is simple and e?ective. Furthermore, when solving the original problem, this proof method can also help the authors recognize the relationship between the propositions of the problem and help the authors generate new geometric propositions.

关键词： Geometry algebra point geometry proof method based on identical equations vector geometry Wu's method

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Modeling and analyzing point cloud generation in missile-borne LiDAR

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Defence Technology（防务技术） 2020年第1期16卷 69-76页

作者： Min-le Li Yi-hua Hu Nan-xiang Zhao Qi-shu Qian State Key Laboratory of Pulsed Power Laser Technology College of Electronic EngineeringNational University of Defense TechnologyHefei230037China Anhui Province Key Laboratory of Electronic Restriction Technology Hefei230037China

The missile-borne LiDAR has an essential prospect in precise guidance.However,the instability of the missile has a significant impact on the precision of LIDAR point cloud,thus modeling and analyzing the influencing factors of point cloud generation is necessary.In this investigation,the authors modeled the point cloud calculation process of missile-borne linear array scanning LiDAR under ideal conditions and analyzed the effect of position change on the fleld of view(FOV) in the course of platform motion.Subsequently,the authors summarized that the stability concerning the field of view and the target tracking are dependent on three limiting conditions.Finally,the authors derived an error formula and analyzed several typical errors in missile platform flight,including scanner error,POS error,system integration error,and platform vibration error.Based on theo retical analysis and simulation experiments,the model proposed in this papier can provide a theoretical basis for the design of the missile-borne LiDAR system and the selection of related instruments in practice.

关键词： LiDAR point cloud Precise guidance Vibration

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Three-dimensional electric potential induced by a point singularity in a multilayered dielectric medium

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Applied Mathematics and Mechanics(English Edition) 2019年第9期40卷 1327-1334页

作者： Xu WANG P. SCHIAVONE School of Mechanical and Power Engineering East China University of Science and Technology Shanghai 200237 China Department of Mechanical Engineering University of Alberta 10-203 Donadeo Innovation Centre for Engineering Edmonton Alberta T6G 1H9 Canada

A simple and effective method is proposed to derive the three-dimensional electric potential induced by a point singularity of any type in an N-phase dielectric medium composed of N-2 intermediate dielectric layers of equal thickness encased in two semi-infinite dielectric media. The point singularity can include a point charge or a point electric dipole. The original boundary value problem for the N-phase medium is reduced to the determination of a single unknown three-dimensional harmonic function through satisfaction of the continuity conditions across all of the N-1 perfect planar interfaces. The single harmonic function can be completely determined after analytically solving the resulting linear recurrence relations, which are independent of the type and the specific location of the singularity. When the singularity is a point charge, we obtain the self-energy of the point charge expressed in terms of a single function and the Coulomb force on the point charge expressed in terms of the negative derivative of this function.

关键词： multilayered dielectric medium point charge point electric dipole linear recurrence relation analytical solution

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Junction point Elimination based Tamil Handwritten Character Recognition:An Experimental Analysis

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Journal of Systems Science and Systems Engineering 2020年第1期29卷 100-123页

作者： M.Antony Robert Raj S.Abirami Department of Information Science and Technology Anna UniversityChennai 600025

Optical Character Recognition is the mechanical or electronic conversion of images of typed,handwritten or printed text into machine-encoded text for online reading and study.In this OCR technique,Tamil handwritten character recognition is one of the most needed and challengeable subjects of research.An encounter between selection and extraction of proper features eliminates the issues faced by the Tamil handwritten recognition.The character and the writers complexities are the major difficulties and challenges faced by this recognition system.Eventually,the character complexity can be overcome by any pre-extraction or selection process,wherein,structured or statistical pre-extraction algorithm can be designed,discovering the essential features,in the case of writer difficulties.The challenges of Tamil handwritten characters are structure over looping;unnecessary character portion;structure discontinuations and so on.The character portions in this research are chosen by implementing a new algorithm called the Junction point Elimination(JPE)after conscientious analysis done on the existing algorithms like Zoning,Zoning and Junction point(ZJP)and the Junction point (JP) based feature pre-extraction process.The novelty behind this work is introducing an algorithm in order to truncate the problem in the existing feature selection and preextraction algorithms.Suitable feature extraction and classification algorithm are chosen and applied on the features extracted by JPE to test whether the same can be reached in successful manner.The final analysis and experiments shows that the JPE is better than the others.

关键词： Junction point elimination chain code zoning prism tree quad tree support vector machine

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Computation of Invariant Curves and Identifying the Type of Critical point

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Journal of Systems Science & Complexity 2018年第6期31卷 1698-1708页

作者： ZHI Junhai CHEN Yufu School of Mathematical Sciences University of Chinese Academy of Sciences

This paper considers two dimensional systems which have purely imaginary eigenvalues.In order to obtain more propositions of invariant curves,the authors transform the real systems into complex differential systems by using a suitable linear transformation.The authors also propose an algorithm to compute exponential factors.An improved method of constructing integrating factor by using all invariant curves is presented and can be used in determining the type of the equilibrium points.

关键词： Complex differential system equilibrium point exponential factor invariant curve

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Selection and Evaluation of Dry and Isentropic Organic Working Fluids Used in Organic Rankine Cycle Based on the Turning point on Their Saturated Vapor Curves

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Journal of Thermal Science 2019年第4期28卷 643-658页

作者： ZHANG Xinxin ZHANG Congtian HE Maogang WANG Jingfu MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China Beijing Key Laboratory of Heat Transfer and Energy Conversion College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’an 710049China

The organic Rankine cycle(ORC)is a popular technique used in the utilization of low-grade thermal energy.Among wet,dry,and isentropic organic working fluids,the latter two types are more appropriate for ORC systems.In this paper,the definition of turning point on saturated vapor curve of dry fluid and isentropic fluid was given according to the shape of the saturated curve of working fluids in a T-s diagram.On this basis,the model of near-critical region triangle was established.Using this model,the thermodynamic performance of 57 kinds of dry and isentropic organic working fluids in ORC was evaluated.The performance includes the relation between turning point temperature and cycle thermal efficiency,the relation between near-critical region triangle area and cycle thermal efficiency,the relation between near-critical region triangle area and exergy at turning point temperature,the relation between near-critical region triangle area and reciprocal value of slope of saturated vapor curve.Moreover,working fluid selection was also conducted in terms of heat source type.It was found through theoretical analysis results that the popular R123 is an acceptable choice especially for the utilization of closed type heat source.Considering it will be phased out in near future,then cis-butene,butane,trans-butene,and isobutene are worth studying as its successor.Dodecane is worthy of attention and further research and it can be a good choice for utilization of open type heat source.

关键词： dry fluid isentropic fluid turning point saturated vapor curve near-critical region triangle Organic Rankine Cycle

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A Geometry-Based point Cloud Reduction Method for MobileAugmented Reality System

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Journal of Computer Science & Technology 2018年第6期33卷 1164-1177页

作者： Hao-Ren Wang Juan Lei Ao Li Yi-Hong Wu National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100190 ChinaUniversity of Chinese Academy of Sciences Beijing 100049 China

In this paper, a geometry-based point cloud reduction method is proposed, and a real-time mobile augmentedreality system is explored for applications in urban environments. We formulate a new objective function which combinesthe point reconstruction errors and constraints on spatial point distribution. Based on this formulation, a mixed integerprogramming scheme is utilized to solve the points reduction problem. The mobile augmented reality system explored inthis paper is composed of the ofttine and online stages. At the offline stage, we build up the localization database usingstructure from motion and compress the point cloud by the proposed point cloud reduction method. While at the onlinestage, we compute the camera pose in real time by combining an image-based localization algorithm and a continuous posetracking algorithm. Experimental results on benchmark and real data show that compared with the existing methods, thisgeometry-based point cloud reduction method selects a point cloud subset which helps the image-based localization methodto achieve higher success rate. Also, the experiments conducted on a mobile platform show that the reduced point cloud notonly reduces the time consuming for initialization and re-initialization, but also makes the memory footprint small, resultinga scalable and real-time mobile augmented reality system.

关键词： mobile platform augmented reality point cloud reduction structure from motion

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An online maximum power point capturing technique for highefficiency power generation of solar photovoltaic systems

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Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 357-368页

作者： Lijun ZHANG Samson Shenglong YU Tyrone FERNANDO Herbert Ho-Ching IU Kit Po WONG Department of Electrical Electronic and Computer Engineering University of Western Australia

This paper proposes a novel high-efficiency generation technique for photovoltaic(PV) system,named maximum power point capturing(MPPC) technique. This is an aperiodic perturbation MPPC technique compared to the conventional periodic perturbation maximum power point tracking technique. Firstly, under a closed-loop circuit and an open-loop circuit,the complete I-V curves and P-V curves are defined. Secondly, the proposed MPPC technique is based on the complete I-V curves and a practical model of solar PV systems.The proposed method realizes that maximum power point(MPP) is captured online, and its control strategy is designed to set a steady operating area around MPP. The duty cycle keeps constant when the operating point is within the steady operating area, i.e., aperiodic perturbation, and when the operating point is outside the steady operating area, MPPC is triggered to capture a new MPP with an updated steady operating area. Simulation results demonstrate that no oscillations exist in steady-state;dynamic performances are improved;and only two perturbations are required to capture the new MPP. Using the proposed MPPC method,low voltage ride through and high voltage ride through can be prevented.

关键词： Photovoltaic systems Maximum power point tracking(MPPT) Maximum power point capturing(MPPC) Complete I–V curves

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Decomposition behaviors of methane hydrate in porous media below the ice melting point by depressurization

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2207-2212页

作者： Yu Zhang Tian Wang Xiaosen Li Kefeng Yan Yi Wang Zhaoyang Chen Guangzhou Institute of Energy Conversion Key Laboratory of Gas HydrateChinese Academy of SciencesGuangzhou 510640China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640China Guangzhou Center for Gas Hydrate Research Chinese Academy of SciencesGuangzhou 510640China University Science&Technology of China Nano Science&Technology InstituteSuzhou 215123China

The decomposition behaviors of methane hydrate below the ice melting point in porous media with different particle size and different pore size were studied.The silica gels with the particle size of 105–150μm,150–200μm and 300–450μm,and the mean pore diameters of 12.95 nm,17.96 nm and 33.20 nm were used in the experiments.Methane recovery and temperature change curves were determined for each experiment.The hydrate decomposition process in the experiments can be divided into the depressurization period and the isobaric period.The temperature in the system decreases quickly in the depressurization process with the hydrate decomposition and reaches the lowest point in the isobaric period.The hydrate decomposition in porous media below ice-melting point is very fast and no self-perseveration effect is observed.The hydrate decomposition is influenced both by the driving force and the initial hydrate saturation.In the experiments with the high hydrate saturation,the hydrate decomposition will stop when the pressure reaches the equilibrium dissociation pressure.The stable pressure in the experiment with high hydrate saturation exceeds the equilibrium dissociation pressure of bulk hydrate and increases with the decrease of the pore size.

关键词： Methane hydrate Depressurization Porous media Decomposition Ice-melting point

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Value of elastography point quantification in improving the diagnostic accuracy of early diabetic kidney disease

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World Journal of Clinical Cases 2019年第23期7卷 3945-3956页

作者： Qiu-Yun Liu Qi Duan Xiao-Hong Fu Li-Qian Fu Hong-Wei Xia Yong-Lin Wan Department of Ultrasound Naval Military Medical University Affiliated Gongli HospitalShanghai 200135Chi Department of Ultrasound Shanghai Hemujia HospitalShanghai 200336China Department of Nephrology Naval Military Medical University Affiliated Gongli HospitalShanghai 200135China

BACKGROUND Diabetic kidney disease(DKD)is a common complication of diabetes.The patient’s prognosis is poor once DKD progresses to advanced stage.Accurate diagnosis and timely treatment of early DKD are important for improving patient’s prognosis and reducing mortality.AIM To explore the value of elastography point quantification(ElastPQ)in improving the accuracy of early DKD diagnosis.METHODS A total of 69 patients with type 2 diabetes were recruited from Naval Military Medical University Affiliated Gongli Hospital.Patients were divided into early DKD group and medium DKD group according to pathological results and urinary albumin excretion rate(UAER).Another 40 patients with simple diabetes were included as the diabetes group.The baseline data,laboratory diagnostic indicators,and ultrasound indicators for each patient were recorded.The differences of the indicators in the three groups were compared.Multivariate logistic regression was used to analyze the influencing factors of the development from simple diabetes into early DKD and from early DKD into medium DKD.Receiver operating characteristic analyses of potential indicators in identifying early DKD and medium DKD,and early DKD and simple diabetes were established.RESULTS Multivariate logistic regression analysis showed that UAER(P0.9].The accuracy of UAER(AUC=0.744),diabetes duration(AUC=0.757),and renocortical YM(AUC=0.782)for the diagnosis of early DKD and simple diabetes were limited.However,the combined diagnosis of UAER,diabe

关键词： Diabetic kidney disease Elastography point quantification Young's Modulus Urinary albumin excretion rate Combined diagnosis Diabetes

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