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Wavelength modulation spectroscopy for measurements of gas parameters in combustion field

Chinese Physics B 2017年第6期26卷 178-186页

作者：屈东胜洪延姬王广宇潘虎 State Key Laboratory of Laser Propulsion & Applications Equipment Academy Beijing 101416 China

A novel wavelength modulation spectroscopy sensor for studying gas properties near 1.4 μm is developed, validated and used in a direct-connect supersonic combustion test facility. In this sensor there are two H2O transitions near 7185.60 cm^-1 and 7454.45 cm^-1 that are used to enable the measurements along the line-of-sight. According to an iterative algorithm, the gas pressure, temperature and species mole fraction can be measured simultaneously. The new sensor is used in the isolator and extender of the supersonic combustion test facility. In the isolator, the sensor resolves the transient and measured pressure, temperature and H2O mole fraction with accuracies of 2.5%, 8.2%, and 7.2%, respectively. Due to the non-uniform characteristic in the extender, the measured results cannot precisely characterize gas properties, but they can qualitatively describe the distinctions of different zones or the changes or fluctuations of the gas parameters.

关键词： wavelength modulation spectroscopy sensor gas properties iterative algorithm

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Efficient thermal analysis method for large scale compound semiconductor integrated circuits based on heterojunction bipolar transistor

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Chinese Physics B 2018年第10期27卷 598-606页

作者： Shi-Zheng Yang Hong-Liang Lv Yu-Ming Zhang Yi-Men Zhang Bin Lu Si-Lu Yan School of Microelectronics Xidian Universitythe State Key Laboratory of Wide Band Gap Semiconductor TechnologyXi＇an 710071China

In this paper, an efficient thermal analysis method is presented for large scale compound semiconductor integrated circuits based on a heterojunction bipolar transistor with considering the change of thermal conductivity with *** influence caused by the thermal conductivity can be equivalent to the increment of the local temperature surrounding the individual device. The junction temperature for each device can be efficiently calculated by the combination of the semianalytic temperature distribution function and the iteration of local temperature with high accuracy, providing a temperature distribution for a full chip. Applying this method to the InP frequency divider chip and the GaAs analog to digital converter chip, the computational results well agree with the results from the simulator COMSOL and the infrared thermal imager respectively. The proposed method can also be applied to thermal analysis in various kinds of semiconductor integrated circuits.

关键词： thermal analysis temperature distribution iterative algorithm compound semiconductor inte-grated circuit

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离散双线性系统二次型最优控制的迭代算法

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高等学校计算数学学报 2007年第3期29卷 216-225页

作者：李俊民孙云平刘赟王元亮西安电子科技大学应用数学系西安电子科技大学应用数学系西安 710071

1引言众所周知,某些复杂的工业过程用线性近似动态模型是不适宜的,而且许多对象如工业生产,生态,生物和社会经济等过程可以用双线性模型自然描述,能够在稳态工作点的一个较大领域内描述一大类严重非线性系统的动态特性,描述精度优于传... 详细信息

1引言众所周知,某些复杂的工业过程用线性近似动态模型是不适宜的,而且许多对象如工业生产,生态,生物和社会经济等过程可以用双线性模型自然描述,能够在稳态工作点的一个较大领域内描述一大类严重非线性系统的动态特性,描述精度优于传统的线性模型

关键词： discrete-time bilinear dynamical system iterative algorithm optimality.

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Modeling Mobile Ticket Dispenser System With Impatient Clerk

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2016年第12期65卷 9931-9941页

作者： Liu, Gi-Ren Lin, Phone Lin, Yi-Bing Natl Tsing Hua Univ Dept Math Hsinchu 300 Taiwan Natl Taiwan Univ Telecommun Res Ctr Grad Inst Networking & Multimedia Dept Comp Sci & Informat Engn Taipei 106 Taiwan Natl Taiwan Univ Grad Inst Med Device & Imaging Taipei 106 Taiwan Natl Chiao Tung Univ Dept Comp Sci & Informat Engn Hsinchu 300 Taiwan

The mobile ticket dispenser system (MTDS) allows customers to remotely draw tickets for service orders anywhere through a mobile handset. In our previous work, the MTDS was applied to a restaurant scenario in which both clerks and customers are patient, i.e., once a mobile ticketing (MT) customer remotely draws the ticket, his request can be served by the clerk when the clerk is available, regardless of when the customer arrives at the restaurant. In this paper, the MTDS is applied to a post office scenario in which the customers are patient, but the clerk is impatient since the original ticket drawn by theMT customer may be invalid if he/she does not arrive at the post office before his/her turn. In this case, the behavior of the MT customer is the same as the so-called in-person ticketing customer who needs to draw a ticket in person when he/she arrives at the service counter. We propose an analytical model to derive the probability that an MT customer misses his/her turn when he/she arrives at the post office. A discrete-event simulation model is developed to investigate the performance of the predicted time adjustment mechanism for the MTDS. We also use real data collected at a post office to observe the queuing behavior. Our study provides guidelines for arranging the time for an MT customer to arrive at the MTDS server.

关键词： iterative algorithm mobile ticket dispenser system (MTDS) performance modeling queueing theory

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iterative Poisson Surface Reconstruction (iPSR) for Unoriented Points

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ACM TRANSACTIONS ON GRAPHICS 2022年第4期41卷 p1-13页

作者： Hou, Fei Wang, Chiyu Wang, Wencheng Qin, Hong Qian, Chen He, Ying Chinese Acad Sci Inst Software State Key Lab Comp Sci Beijing Peoples R China SUNY Stony Brook Dept Comp Sci Stony Brook NY 11794 USA SenseTime Res Beijing Peoples R China Tetras AI Beijing Peoples R China Nanyang Technol Univ Sch Comp Sci & Engn Singapore Singapore Nanyang Technol Univ S Lab Singapore Singapore

Poisson surface reconstruction (PSR) remains a popular technique for reconstructing watertight surfaces from 3D point samples thanks to its efficiency, simplicity, and robustness. Yet, the existing PSR method and subsequent variants work only for oriented points. This paper intends to validate that an improved PSR, called iPSR, can completely eliminate the requirement of point normals and proceed in an iterative manner. In each iteration, iPSR takes as input point samples with normals directly computed from the surface obtained in the preceding iteration, and then generates a new surface with better quality. Extensive quantitative evaluation confirms that the new iPSR algorithm converges in 5-30 iterations even with randomly initialized normals. If initialized with a simple visibility based heuristic, iPSR can further reduce the number of iterations. We conduct comprehensive comparisons with PSR and other powerful implicit-function based methods. Finally, we confirm iPSR's effectiveness and scalability on the AIM@SHAPE dataset and challenging (indoor and outdoor) scenes. Code and data for this paper are at https://***/houfei0801/ipsr.

关键词： Unoriented points Poisson surface reconstruction iterative algorithm

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Reconstruction of Partially Occluded Facial Image for Classification

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IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 2021年第4期16卷 600-608页

作者： Zou, Min You, Mengbo Akashi, Takuya Iwate Univ Grad Sch Engn Morioka Iwate 0208551 Japan Northwest A&F Univ Coll Informat Engn Yangling 712100 Shaanxi Peoples R China Iwate Univ Fac Sci & Engn Morioka Iwate 0208551 Japan

The recent literature indicates that face recognition and facial expression classification has achieved a high accuracy on benchmark datasets with a large number of face images in the wild. On the other hand, unlike the purpose of recognizing as many people as possible, real applications for families or companies usually aim to recognize a small group of people as accurate as possible. In case of the face is partially occluded, convolutional solutions always simply put images with occlusions into the training dataset and hope the convolution neural network learn a model robust to partial occlusion. These processes not only increase the burden of learning, but also affect the model to identify normal images without occlusions. In this paper, we investigate the research problem of facial image reconstruction to discard the influence of partial occlusion. Based on the phenomenon that human faces are roughly symmetrical, we propose to reconstruct the facial information of occluded areas with the intact half face. Specifically, occlusion on the left-half face is reconstructed with a linear combination of features on the right-half face and vice versa. The process is modeled by keeping row sparsity for the coefficient matrix with l(2,1)-norm regularization while minimizing the reconstruction error. An alternative iterative algorithm is proposed to solve the optimization problem. To validate the effectiveness of the reconstruction, we fine-tune a pretrained model, AlexNet, training on normal face images and test with various occluded images. Extensive experimental results show that our method has improved the classification performance effectively. (c) 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

关键词： face reconstruction partial occlusion iterative algorithm flipping strategy

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Clothoids Composition Method for Smooth Path Generation of Car-Like Vehicle Navigation

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JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS 2017年第1期88卷 129-146页

作者： Gim, Suhyeon Adouane, Lounis Lee, Sukhan Derutin, Jean-Pierre Sungkyunkwan Univ Seoburo 2066 Suwon 440746 South Korea Univ Clermont Auvergne Inst Pascal IMobS3 CNRS SIGMA F-63000 Clermont Ferrand France

This paper addresses a continuous curvature path generation problem for car-like vehicle navigation. The continuous curvature path is generated by multiple clothoids composition and parametric adjustment. According to the geometric conditions of the given initial and final configurations, the path generation problem is classified into two cases and then, each problem is solved by by appropriate proposed algorithm. The solution is obtained by iterative procedure subject to geometric constraint as well as solution constraints. For computational efficiency and fast convergence in the proposed algorithms, a minimax sharpness constraint is proposed as the solution constraint by minimizing the maximum sharpness of the feasible solutions. After the generation of the proposed path, the resultant curvature/sharpness diagram provides a useful information about its orientation and curvature continuity along the travel length. The proposed path planning strategy, permits us to obtain online, smooth and safe path between two defined configurations while ensuring high passengers comfort (continuous curvature and transition between the different composed clothoids). The algorithmic proposals have been applied to generate continuous curvature for two cases. The first correspond to local path planning for ensuring obstacle avoidance or lane change. The second application corresponds to global path smoothing. The resultant global path path is tested on the Lyapunov-based control scheme and showed improved performance on its steering work (reduction of 41.0% than the driving based on the raw data), which permits us therefore to validate the effectiveness of the obtained global path for car-like vehicles path following.

关键词： Continuous curvature path planning iterative algorithm Minimax sharpness constraint Nonholonomic car-like vehicle Curvature and sharpness diagram

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An iterative method for updating gyroscopic systems based on measured modal data

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APPLIED MATHEMATICS AND COMPUTATION 2011年第7期218卷 3753-3762页

作者： Yuan, Yongxin Jiangsu Univ Sci & Technol Sch Math & Phys Zhenjiang 212003 Peoples R China

An efficient iterative method for updating the mass, gyroscopic and stiffness matrices simultaneously using a few of complex measured modal data is developed. By using the proposed iterative method, the unique symmetric solution can be obtained within finite iteration steps in the absence of roundoff errors by choosing a special kind of initial matrices. Numerical results show that the presented method can be used to update finite element models to get better agreement between analytical and experimental modal parameters. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Model updating iterative algorithm Gyroscopic system Partially prescribed spectral data Optimal approximation

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Strong stabilisation by output feedback controller for linear systems with delayed input

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IET CONTROL THEORY AND APPLICATIONS 2012年第10期6卷 1329-1340页

作者： Du, B. Lam, J. Shu, Z. Nanjing Univ Sci & Technol Dept Automat Nanjing 210094 Jiangsu Peoples R China Univ Hong Kong Dept Mech Engn Hong Kong Hong Kong Peoples R China Univ Southampton Fac Engn & Environm Electromech Grp Southampton SO17 1BJ Hants England

This study addresses the strong stabilisation problem for continuous-time linear systems with an unknown input delay via dynamic output feedback controllers. A new criterion for dynamic output feedback stabilisability is proposed in terms of matrix inequalities with the separation of the controller gain with the Lyapunov matrix and the system matrices. Based on these new characterisations, an iterative algorithm is given to design the dynamic output feedback controllers with the initial values obtained by some proposed state feedback stabilisation methods. The effectiveness and merits of the proposed approach are shown through several examples.

关键词： dynamic output feedback controller dynamic output feedback stabilisability Lyapunov matrix continuous time linear system stability Stability in control theory state feedback Lyapunov matrix equations linear systems feedback Algebra system matrices state feedback stabilisation method continuous time systems linear matrix inequalities matrix inequalities iterative algorithm delayed input controller gain strong stabilisation problem

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iterative dual energy material decomposition from spatial mismatched raw data sets

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JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2014年第6期22卷 745-762页

作者： Zhao, Xing Hu, Jing-Jing Zhao, Yun-Song Zhang, Hui-Tao Zhang, Peng Capital Normal Univ Sch Math Sci CT Lab Beijing 100048 Peoples R China Beijing Inst Technol Sch Software Beijing 100081 Peoples R China Beijing Ctr Math & Informat Interdisciplinary Sci Beijing Peoples R China

Today's clinical dual energy computed tomography (DECT) scanners generally measure different rays for different energy spectra and acquire spatial mismatched raw data sets. The deficits in clinical DECT technologies suggest that mainly image based material decomposition methods are in use nowadays. However, the image based material decomposition is an approximate technique, and beam hardening artifacts remain in decomposition results. A recently developed image based iterative method for material decomposition from inconsistent rays (MDIR) can achieve much better image quality than the conventional image based methods. Inspired by the MDIR method, this paper proposes an iterative method to indirectly perform raw data based DECT even with completely mismatched raw data sets. The iterative process is initialized by density images that were obtained from an image based material decomposition. Then the density images are iteratively corrected by comparing the estimated polychromatic projections and the measured polychromatic projections. Only three iterations of the method are sufficient to greatly improve the qualitative and quantitative information in material density images. Compared with the MDIR method, the proposed method needs not to perform additional water precorrection. The advantages of the method are verified with numerical experiments from inconsistent noise free and noisy raw data.

关键词： Dual energy computed tomography iterative algorithm basis material decomposition calibration

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