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Radiance-based color calibration for image-based modeling with multiple cameras

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science China(Information sciences) 2012年第7期55卷 1509-1519页

作者： ZHAO Xu 1,2.,ZHOU Zhong 1,2.& WU Wei 1,2.1 State Key Laboratory of Virtual Reality Technology and systems,beihang{2.,beijing 100191,China 2.School of Computer science and Engineering,beihang{2.,beijing 100191,China 1. State Key Laboratory of Virtual Reality Technology and systems Beihang University Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

Photo-consistency estimation is an important part for many image-based modeling *** paper presents a novel radiance-based color calibration method to reduce the uncertainty of photo-consistency estimation across multiple *** idea behind our method is to convert colors into a uniform radiometric color space in which multiple image data are *** results demonstrate that our method can achieve comparable color calibration effect without adjusting camera parameters and is more robust than other existing ***,we obtain an auto-determined threshold for photo-consistency check,which will lead to a better performance than existing photo-consistency based reconstruction algorithms.

关键词： color calibration photo-consistency estimation multi-camera system image-based modeling

Large field of view computed laminography with the asymmetric rotational scanning geometry

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science China(Technological sciences) 2010年第8期53卷 2261-2271页

作者： FU Jian 1,2.,JIANG BaiHong&LI Bin 1 School of Mechanical Engineering and Automation,beihang{2.,beijing 100191,China 2.Research Center of Digital Radiation Imaging and Biomedical Imaging,beihang{2.,beijing 100191,China 1. School of Mechanical Engineering and Automation Beihang University Beijing 100191 China2. Research Center of Digital Radiation Imaging and Biomedical Imaging Beihang University Beijing 100191 China

X-ray computed laminography(CL)is used in the fields of industrial inspection and medical *** can provide the internal structure three-dimensional(3D)information of a region of the objects *** is important to the clinical diagnosis and the quality control of flat objects like printed circuit boards,aircraft wings and satellite solar *** the restriction that the imaging region must be within the X-ray beam formed by the X-ray source and the detector,the imaging field of view of CL is limited by the size of detector.A new CL method with an asymmetric rotational cone-beam scanning geometry,called large field of view CL,is presented to overcome the existing *** can extend the imaging region when the imaging spatial resolution keeps the same as that of the conventional *** can also improve the imaging spatial resolution when the imaging region keeps the same as that of the conventional *** asymmetric configuration can be achieved by offsetting the detector from the conventional symmetric *** does not,however,require new detectors and X-ray source nor alter the scanning mechanical *** filtered back-projection(FBP)reconstruction algorithm and the data truncation smoothing functions have been deduced to reconstruct the images directly from the data acquired with this asymmetric *** performed numerical studies and experiments to demonstrate and validate the proposed approach. Results in these studies and experiments confirm that the proposed method can enlarge the imaging region and improve the spatial *** proposed approach may find applications in the CL system with the rotational scanning geometry.

关键词： computed laminography image reconstruction reconstruction algorithm imaging field of view imaging spatial resolution

AutoSyn:A new approach to automated synthesis of composite web services with correctness guarantee

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science in China(Series F) 2009年第9期52卷 1534-1549页

作者： HUAI JinPeng1,2.DENG Ting1,2.LI XianXian1,2.DU ZongXia1,2.& GUO HuiPeng1,2.1 National Laboratory of Software Development Environment,beihang university,{2. 100191,China 2.School of Computer science & Engineering,beihang university,{2. 100191,China National Laboratory of Software Development Environment Beihang University Beijing 100191 China School of Computer science & Engineering Beihang University Beijing 100191 China

How to compose existing web services automatically and to guarantee the correctness of the design （e.g. freeness of deadlock and unspecified reception, and temporal constraints） is an important and challenging problem in web services. Most existing approaches require a detailed specification of the desired behaviors of a composite service beforehand and then perform certain formal verification to guarantee the correctness of the design, which makes the composition process both complex and time-consuming. In this paper, we propose a novel approach, referred to as AutoSyn to compose web services, where the correctness is guaranteed in the synthesis process. For a given set of services, a composite service is automatically constructed based on L＊ algorithm, which guarantees that the composite service is the most general way of coordinating services so that the correctness is ensured. We show the soundness and completeness of our solution and give a set of optimization techniques for reducing the time consumption. We have implemented a prototype system of AutoSyn and evaluated the effectiveness and efficiency of AutoSyn through an experimental study.

关键词： business protocol synthesis composite service correctness constraints L* algorithm

Filterless Photosensors with Intrinsic Color Perception and Flexibility

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Chemical Research in Chinese Universities 2024年第5期40卷 894-900页

作者： ZHOU Hongtao XU beihang ZHENG Xinjia GONG Jinchao ZHANG Kaitong HE Yonglin Key Laboratory of Advanced Light Conversion Materials and Biophotonics School of Chemistry and Life ResourcesRenmin University of ChinaBeijing100872P.R.China School of mathematics Renmin University of ChinaBeijing100872P.R.China

Sensing materials possessing intrinsic color perception are indispensable prerequisites for the development of filterless photosensors,which could eliminate the need for complex device designs and avoid color distortion in *** materials are constrained by complex processing methods and limited ***,a color-photosensitive array based on ionic liquid with selective photothermal conversion(ILSPC)has been developed for intrinsic color *** on the selective absorption,photothermal conversion,and thermosensitivity of ILSPC,a photo-thermo-electric sensing system has been ***,the versatility of the two algorithms has been validated in color reconstruction and electrical signal *** an exploration,the photosensitive array showcases promising color recognition capabilities,potentially propelling the evolution of flexible photosensors.

关键词： Ionic liquid Filterless Intrinsic color perception Selective photothermal conversion Photosensitive array

Progress of Lyman-alpha-based beam emission spectroscopy(Ly BES)diagnostic on the HL-2. tokamak

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Plasma science and Technology 2024年第3期26卷 118-125页

作者：周艺轩余羿许敏柯锐聂林徐皓赵光义刘灏袁子豪肖晨雨李继全肖池阶 the HL-2. Team Southwestern Institute of Physics Chengdu 610041People's Republic of China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082People's Republic of China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China

An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2. *** 2.-channel edge LyBES,which is intended to measure the density fluctuation in plasma edge(from R=1960 mm to R=2.2. mm)with an improved spatial resolution of 3.3 mm,is a complement to the existing conventional beam emission spectroscopy(BES)*** this article,we introduce the progress of LyBES diagnostic,including the collection optics,the monochromator,and the detector *** reflectance of the collection mirrors is measured to be~82.at 12. nm,and the aberration geometrical radius of the collection optics is tested to be~150μm in the aimed *** linear dispersion of the LyBES monochromator is designed to be~0.09 nm mm^(-1).The bandwidth of the detector system with the 5×10^(7)V A^(-1)preamplifier gain is measured to be~2.0 kHz,and the peak-to-peak noise of the detector system is tested to be~16 *** finalized design,components development and testing of the LyBES diagnostic have been completed at present,and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2. campaign.

关键词： density fluctuation Ly BES BES vacuum ultraviolet

Intermediate processes and critical phenomena: Theory, method and progress of fractional operators and their applications to modern mechanics

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science China(Physics,Mechanics & Astronomy) 2006年第3期49卷 257-272页

作者： XU Mingyu1 & TAN Wenchang2.1. Institute of Applied mathematics, School of Math &{2. science, Shandong university, Jinan 2.0100, China 2. State Key Laboratory of Turbulence and Complex{2.s & Department of Mechanics and Engineering science, Peking university, beijing 100871, China 1. Institute of Applied mathematics School of Math & System Science Shandong University Jinan 250100 China 2. State Key Laboratory of Turbulence and Complex systems & Department of Mechanics and Engineering science Peking University Beijing 100871 China

From point of view of physics, especially of mechanics, we briefly introduce fractional operators (with emphasis on fractional calculus and fractional differential equa- tions) used for describing intermediate processes and critical phenomena in physics and mechanics, their progress in theory and methods and their applications to modern me- chanics. Some authors’ researches in this area in recent years are included. Finally, prospects and evaluation for this subject are made.

关键词： fractional operators,intermediate processes,critical phenomena,modern mechanics

The numerical method for three-dimensional impact with friction of multi-rigid-body system

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science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 102-118页

作者： ZHAO Zhen1,2. LIU Caishan2.& CHEN Bin2.1. beijing Institute of Graphic Communication, beijing 102.00, China 2. Department of Mechanics & Engineering{2., Peking university, beijing 100871, China beijing Institute of Graphic Communication Beijing 102600 China Department of Mechanics & Engineering science Peking University Beijing 100871 China

The differential equations for planar impacts reduce to an algebraic form, and can be easily solved. For three dimensional impacts with friction, there is no closed-form solution, and numerical integration is required due to the swerve behavior of tangential impulse during collisions. The dynamic governing equations in the impact process are built up in impulse space based on the Lagrangian equation in this paper. The coefficient of restitution defined by Poisson is used as the condition of impact termination. A valid nu- merical method for solving three-dimensional frictional impact of multi-rigid body system is established. The singular cases of tangential movement in sticking point are especially noticed and analyzed. Several examples are present to reveal the different kinds of tan- gential movement modes varied with the normal impulse during collision.

关键词： multi-rigid body, impact, friction.

Some properties on multivariate filter banks with a matrix factorization

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Progress in Natural science:Materials International 2005年第2期15卷 20-30页

作者： LIAN Qiaofang1, XIAO Hongying2. and CHEN Qiuhui3(1. Department of mathematics, beijing Jiaotong{2., beijing 100044, China 2. Institute of mathematics, Academy of mathematics and system sciences, Chinese Academy of sciences, beijing 100080, China 3. Department of Scientific Computing and Computer Applications, Zhongshan{2., Guangzhou 5102.5, China) Department of mathematics Beijing Jiaotong University Beijing 100044 China. Institute of mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China. Department of Scientific Computing and Computer Applications Zhongshan University Guangzhou 510275 China

A class of multivariate filter banks with a matrix factorization has been developed by Chen et al. The main purpose of this paper is to discuss some further properties of this kind of filter bank, such as the completeness, accuracy of the corresponding scaling functions and the relationships with Daubechies' wavelets and the multi-wavelets provided by Chui and Lian. Moreover, some examples are given to show that this kind of filter bank has a higher accuracy for the scaling functions.

关键词： filter banks completeness accuracy matrix factorization

A Linear Domain system Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Genetic Algorithm

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Journal of Bionic Engineering 2010年第2期7卷 142-149页

作者： Xusheng Lei,Yuhu Du School of the Instrumentation science and Opto-Electronic Engineering,{2. university,beijing 100191,P.R.China [a] School of the Instrumentation science Opto-Electronic Engineering Beihang University Beijing 100191 P. R. China

This paper proposes a new adaptive linear domain system identification method for small unmanned aerial *** the flash memory integrated into the micro guide navigation control module, system records the data sequences of flighttests as inputs (control signals for servos) and outputs (aircraft’s attitude and velocity information).After data preprocessing, thesystem constructs the horizontal and vertical dynamic model for the small unmanned aerial rotorcraft using adaptive *** identified model is verified by a series of simulations and *** between flight data and the one-stepprediction data obtained from the identification model shows that the dynamic model has a good estimation for real unmannedaerial rotorcraft *** on the proposed dynamic model, the small unmanned aerial rotorcraft can perform hovering,turning, and straight flight tasks in real flight tests.

关键词： small unmanned aerial rotorcraft dynamic space model model identification adaptive genetic algorithm