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A LINE SEARCH FILTER INEXACT SQP METHOD FOR NONLINEAR EQUALITY CONSTRAINED OPTIMIZATION

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Journal of Systems Science & Complexity 2012年第5期25卷 950-963页

作者： Li cai Detong ZHU Department of Mathematics Shanghai Normal University College of Business Shanghai Normal University

This paper proposes an inexact SQP method in association with line search filter technique for solving nonlinear equality constrained optimization. For large-scale applications, it is expensive to get an exact search direction, and hence the authors use an inexact method that finds an approximate solution satisfying some appropriate conditions. The global convergence of the proposed algorithm is established by using line search filter technique. The second-order correction step is used to overcome the Maratos effect, while the line search filter inexact SQP method has q-superlinear local convergence rate. Finally, the results of numerical experiments indicate that the proposed method is efficient for the given test problems.

关键词： Constrained optimization convergence filter method inexact method maratos effect.

Human Following for Outdoor Mobile Robots Based on Point-Cloud's Appearance Model

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Chinese Journal of Electronics 2021年第6期30卷 1087-1095页

作者： GONG Linxi cai Yunfei School of Computer Science and Engineering Nanjing University of Science and Technology

In this paper, we propose a point-cloudbased algorithm for human-following robots to detect and follow the target person in a complex outdoor environment. Specifically, we exploit Ada Boost to train a binary classifier in a designed feature space based on sparse point-cloud to distinguish the target person from other objects. Then a particle filter is applied to continuously track the target’s position. Motivated by the interference of obstacles in long-distance human-following scenarios, a motion plan algorithm based on vector field histogram is adopted. Experiments are carried out both on the dataset we collected and in real application scenarios. The results show that our algorithm has the ability of real-time target detection and tracking, and is robust to deal with complex situations in outdoor environments.

关键词： outdoor environments outdoor mobile robots particle filter target person point-cloud-based algorithm path planning collision avoidance designed feature space binary classifier mobile robots tracking real-time target detection particle filtering (numerical methods) sparse point-cloud learning (artificial intelligence) complex outdoor environment motion plan algorithm vector field histogram object detection

Recent progress in electric-field assisted combustion: a brief review

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Frontiers in Energy 2022年第6期16卷 883-899页

作者： Hecong LIU Weiwei cai Key Laboratory of the Ministry of Education for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The control of combustion is a hot and classical *** the combustion technologies,electric-field assisted combustion is an advanced technology that enjoys major advantages such as fast response and low power consumption compared with thermal ***,its fundamental principle and impacts on the flames are complicated due to the coupling between physics,chemistry,and *** the last two decades,tremendous efforts have been made to understand electric-field assisted *** observations have been reported based on different combustion systems and improved *** main impacts,including flame stabilization,emission reduction,and flame propagation,have been revealed by both simulative and experimental *** findings significantly facilitate the application of electric-field assisted *** brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词： electric field combustion flame stabilization emission reduction flame propagation

A survey of operating system support for persistent memory

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Frontiers of Computer Science 2021年第4期15卷 29-48页

作者： Miao cai Hao HUANG Department of Computer Science and Technology Nanjing UniversityNanjing 210023China

Emerging persistent memory technologies,like PCM and 3D XPoint,offer numerous advantages,such as higher density,larger capacity,and better energy efficiency,compared with the ***,they also have some drawbacks,e.g.,slower access speed,limited write endurance,and unbalanced read/write *** memory technologies provide both great opportunities and challenges for operating *** a result,a large number of solutions have been *** the increasing number and complexity of problems and approaches,we believe this is the right moment to investigate and analyze these works *** this end,we perform a comprehensive and in-depth study on operating system support for persistent memory within three ***,we present an overview of how to build the operating system on persistent memory from three perspectives:system abstraction,crash consistency,and system ***,we classify the existing research works into three categories:storage stack,memory manager,and OS-bypassing *** each category,we summarize the major research topics and discuss these topics ***,we present the challenges and opportunities in each topic,describe the contributions and limitations of proposed approaches,and compare these solutions in different ***,we also envision the future operating system based on this study.

关键词： persistent memory operating system survey

Recent progress in the interaction between energetic particles and tearing modes

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National Science Review 2022年第11期9卷 240-261页

作者： Huishan cai Ding Li Chinese Academy of Sciences Key Laboratory of Geospace Environment School of Nuclear Sciences and TechnologyUniversity of Science and Technology of China Institute of Physics Chinese Academy of Sciences Songshan Lake Materials Laboratory

The dynamics of energetic particles and tearing modes and the interactions between them are of great significance for magnetically confined fusion plasmas. In this review, we focus on these issues in the context of tokamak plasmas. The interaction between energetic particles and tearing modes is considered from two perspectives:(i) the influence of energetic particles on tearing modes and(ii) the transport of energetic particles by tearing modes. The influence of energetic particles on tearing modes is described on the basis of a general dispersion relation for tearing modes. The effects of energetic particles are considered separately in the outer region and the island region of a tearing mode. The physics mainly results from the modification of the perturbed parallel current by energetic particles without wave–particle resonance. In addition, the resonance between energetic particles and tearing modes is also reviewed. For the transport of energetic particles, transport of both circulating and trapped energetic particles by tearing mode is reviewed. Our descriptions of physical phenomena here are based on an analytical approach, while the experiments and simulations are used to illustrate and confirm our results. Finally, a number of open issues are discussed.

关键词： magnetically confined plasma energetic particle tearing mode transport confinement tokamak

High-resolution sea surface wind speeds of Super Typhoon Lekima (2019) retrieved by Gaofen-3 SAR

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Frontiers of Earth Science 2022年第1期16卷 90-98页

作者： He FANG william PERRIE Gaofeng FAN Zhengquan LI Juzhen cai Yue HE Jingsong YANG Tao XIE Xuesong ZHU Zhejiang Climate Centre Hangzhou 310017China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Shanghai Typhoon Institute and Key Laboratory of Numerical Modeling for Tropical Cyclone of China Meteorological AdministrationShanghai 200030China Fisheries&Oceans Canada Bedford Institute of OceanographyDartmouth B2Y4A2Canada School of Remote Sensing and Geomatics Engineering Nanjing University of Information Science and TechnologyNanjing 210044China

Gaofen-3(GF-3)is the first Chinese spaceborne multi-polarization synthetic aperture radar(SAR)instrument at C-band(5.43 GHz).In this paper,we use data collected from GF-3 to observe Super Typhoon Lekima(2019)in the East China *** a VH-polarized wide ScanSAR(WSC)image,ocean surface wind speeds at 100m horizontal resolution are obtained at 21:56:59 UTC on 8 August 2019,with the maximum wind speed,38.9 m·s^(-1).Validating the SAR-retrieved winds with buoymeasured wind speeds,we find that the root mean square error(RMSE)is 1.86 m·s^(-1),and correlation coefficient,*** suggests that wind speeds retrieved from GF-3 SAR are *** the European Centre for MediumRange Weather Forecasts(ECMWF)fine grid operational forecast products with spatial resolution,and China Global/Regional Assimilation and Prediction Enhance System(GRAPES)have good performances on surface wind prediction under weak wind speed condition(24m·s^(-1)).With respect to SAR-retrieved wind speeds,the RMSEs are 5.24 m·s^(–1) for ECMWF and 5.17 m·s^(–1) for GRAPES,with biases of 4.16 m·s^(–1) for ECMWF and 3.84 m·s^(-1)for GRAPES during Super Typhoon Lekima(2019).

关键词： synthetic aperture radar wind speed numerical weather predication(NWP) typhoon

Cavitation dynamics in a vitrimer

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Acta Mechanica Sinica 2021年第5期37卷 767-772,I0001页

作者： Zhaoqiang Song Shengqiang cai Department of Mechanical and Aerospace Engineering University of CaliforniaSan DiegoLa JollaCA 92093USA

Vitrimer is a polymer network with dynamic covalent bonds,which can be dynamically broken and *** to the dynamic covalent bonds,vitrimer behaves like an elastomer at high deformation rate or low temperature but a viscous fluid at low deformation rate or high *** this article,we study the cavitation dynamics in a vitrimer,which is known to be an important damaging mechanism in *** the formulation,a nonlinear three-dimensional rate-dependent constitutive model for the vitrimer is adopted,in which both of the strain stiffening and the kinetics of dynamic exchanging reactions are *** theory predicts strong dependence of the cavitation dynamics on the loading *** computational results may help to reveal some critical insights into the rate-dependent fracture in vitrimer.

关键词： Vitrimer Cavitation dynamics Strain stiffening Viscoelasticity

Orderliness of Hydrocarbon Accumulation Distribution in Rift Basins of Eastern China

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Acta Geologica Sinica(English Edition) 2012年第3期86卷 779-787页

作者： cai Xiyuan China Petroleum and Chemical Corporation Beijing 100728

The Cenozoic rift basins in eastern China show a clear temporal and spatial zonation and episodic tectonic evolution, which control their episodic hydrocarbon generation and zonal accumulation. In this paper, based on the study of depositional architecture, hydrocarbon migration system and dynamic evolution in the rift basins, combinations of hydrocarbon accumulation elements were analyzed using sequence stratigraphy. Hydrocarbon distribution in system tracts with different sequence orders was further studied. And we summarized stacking patterns and horizontal combination relationships for different types of reservoirs, such as lithological, tectonic-lithological, tectonic and stratigraphical reservoirs which can be observed from depression center to basin margin. The result reveals that various scales of pools exhibit significant distribution and evolution orderliness in different pool-forming units, i.e., depositional systems, plays and depressions. The regular distribution of various scales of pools is closely related to tectonic evolution and depositional filling in the rift basins. The result can be applied to the fine petroleum exploration in rift basins in eastern China. It will promote the scientific prediction and evaluation of reservoir types and their spatial distribution, lead to the active shifts of exploration targets in different zones, and thus support the stable progress of fine exploration in mature exploration areas.

关键词： rift basin pathway system reservoir-forming element distribution regularity of hydrocarbon accumulation Cenozoic

Asymptotic stability of port-hamiltonian systems with constant inputs

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Control Theory and Technology 2021年第2期19卷 227-235页

作者： Liangcheng cai School of Electric Engineer Southwest Jiaotong UniversityChengduSichuan610031China

In this paper, the asymptotic stability of Port-Hamiltonian (PH) systems with constant inputs is studied. Constant inputs are useful for stabilizing systems at their nonzero equilibria and can be realized by step signals. To achieve this goal, two methods based on integral action and comparison principle are presented in this paper. These methods change the convex Hamiltonian function and the restricted damping matrix of the previous results into a Hamiltonian function with a local minimum and a positive semidefinite matrix, respectively. Due to common conditions of Hamiltonian function and damping matrix, the proposed method asymptotically stabilizes more classes of PH systems with constant inputs than the existing methods. Finally, the validity and advantages of the presented methods are shown in an example.

关键词： Port-Hamiltonian systems Constant inputs Integral action Compare principle Asymptotic stability