检索结果-南通市图书馆

A Character Flow Framework for Multi-Oriented Scene Text Detection

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2021年第3期36卷 465-477页

作者： wen-Jun Yang Bei-Ji zou Kai-wen Li Shu Liu School of Computer Science and Engineering Central South UniversityChangsha410083China Hunan Engineering Research Center of Machine Vision and Intelligent Medicine Changsha410083China

Scene text detection plays a significant role in various applications,such as object recognition,document management,and visual *** instance segmentation based method has been mostly used in existing research due to its advantages in dealing with multi-oriented ***,a large number of non-text pixels exist in the labels during the model training,leading to text *** this paper,we propose a novel multi-oriented scene text detection framework,which includes two main modules:character instance segmentation(one instance corresponds to one character),and character flow construction(one character flow corresponds to one word).We use feature pyramid network(FPN)to predict character and non-character instances with arbitrary directions.A joint network of FPN and bidirectional long short-term memory(BLSTM)is developed to explore the context information among isolated characters,which are finally grouped into character *** experiments are conducted on ICDAR2013,ICDAR2015,MSRA-TD500 and MLT datasets to demonstrate the effectiveness of our *** F-measures are 92.62%,88.02%,83.69%and 77.81%,respectively.

关键词： multi-oriented scene text detection character instance segmentation character flow feature pyramid network(FPN) bidirectional long short-term memory(BLSTM)

Three-stage Defensive Framework for Distributed Microgrid Control Against Cyberattacks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1669-1678页

作者： Xuanyi Xiao quan Zhou Feng Wang wen Huang College of Electrical and Information Engineering Hunan UniversityChangsha 410082China IEEE

With the wide integration of various distributed communication and control techniques,the cyber-physical microgrids face critical challenges raised by the emerging *** paper proposes a three-stage defensive framework for distributed microgrids against denial of service(DoS)and false data injection(FDI)attacks,including resilient control,communication network reconfiguration,and switching of local *** resilient control in the first stage is capable of tackling simultaneous DoS and FDI attacks when the connectivity of communication network could be maintained under *** communication network reconfiguration method in the second stage and the subsequent switching of local control in the third stage based on the software-defined network(SDN)layer aim to cope with the network partitions caused by *** proposed defensive framework could effectively mitigate the impacts of a wide range of simultaneous DoS and FDI attacks in microgrids without requiring the specific assumptions of attacks and prompt detections,which would not incorporate additional cyberattack *** case studies using a 13-bus microgrid system are conducted to validate the effectiveness of the proposed three-stage defensive framework against the simultaneous DoS and FDI attacks.

关键词： Microgrid cyber-physical systems cyberattack distributed control defensive framework

Multiplicity of Solutions for a Class of Kirchhoff Type Problems

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2010年第3期26卷 387-394页

作者： Xiao-ming He wen-ming zou School of Science Minzu University of China Beijing 100081 China Department of Mathematical Sciences Tsinghua University Beijing 100084 China

In this paper we apply the （variant） fountain theorems to study the symmetric nonlinear Kirch- hoff nonlocal problems. Under the Ambrosetti-Rabinowitz＇s 4-superlinearity condition, or no Ambrosetti- Rabinowitz＇s 4-superlinearity condition, we present two results of existence of infinitely many large energy solutions, respectively.

关键词： Kirchhoff nonlocal problems Multiple solutions Fountain theorems

A Concentration Behavior for Semilinear Elliptic Systems with Indefinite Weight

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2014年第12期30卷 2014-2026页

作者： Xue Xiu ZHONG wen Ming zou Department of Mathematical Sciences Tsinghua University

Consider the Schrodinger system{-Δu＋V1,nu=αQn（x）︱u︱^α-2u︱v︱^β,-Δv＋V2,nv=βQn（x）︱u︱^α︱v︱^β-2v,u,v∈H0^1（Ω） where Ωbelong to R^N,α,β〉 1,α ＋ β〈 2^＊ and the spectrum σ（-△ ＋ V（i,n））（0,＋∞）,i = 1,2;Qn is a bounded function and is positive in a region contained in Ω and negative ***,the sets{Qn 〉 0} shrink to a point x0∈ Ω as n→＋∞.We obtain the concentration ***,we first show that the system has a nontrivial solution（un,vn） corresponding to Qn,then we prove that the sequences（un） and（vn） concentrate at x0 with respect to the H^***,if the sets {Qn 〉 0} shrink to finite points and（un,vn） is a ground state solution,then we must have that both un and vn concentrate at exactly one of these ***,the concentration of un and vn occurs at the same ***,we generalize the results due to Ackermann and Szulkin[*** ***.,207,1075-1089（2013）].

关键词： Schrodinger systems concentration ground state solution

Grasp evaluation and contact points planning for polyhedral objects using a ray-shooting algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第3期13卷 218-231页

作者： Shuang-quan wen Tie-jun WU Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

Grasp evaluation and planning are two fundamental issues in robotic grasping and dexterous manipulation. Most traditional methods for grasp quality evaluation suffer from non-uniformity of the wrench space and a dependence on the scale and choice of the reference frame. To overcome these weaknesses, we present a grasp evaluation method based on disturbance force rejection under the assumption that the normal component of each individual contact force is less than one. The evaluation criterion is solved using an enhanced ray-shooting algorithm in which the geometry of the grasp wrench space is read by the support mapping. This evaluation procedure is very fast due to the efficiency of the ray-shooting algorithm without linearization of the friction cones. Based on a necessary condition for grasp quality improvement, a heuristic searching algorithm for polyhedral object regrasp is also proposed. It starts from an initial force-closure unit grasp configuration and iteratively improves the grasp quality to find the locally optimum contact points. The efficiency and effectiveness of the proposed algorithms are illustrated by a number of numerical examples.

关键词： Force closure Grasp quality evaluation Multifingered grasp Grasping planning Ray-shooting

Thermal-force control ability under variation of electromagnetic stick structure parameters in RPECT

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第1期31卷 224-236页

作者： Ting-song Yang wen-quan Sun Feng-shan Du An-rui He quan Yang National Engineering Research Center of Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing100083China Institute of Engineering and Technology University of Science and Technology BeijingBeijing100083China College of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina

Thermal-force driving of roll profile electromagnetic control technology(RPECT),which can be used to adjust the roll profile,can be affected by the sequential temperature rise between the electromagnetic stick(ES)and electromagnetic control *** to the limited space of ES and induction coil,the cross-sectional area of induction coil can be inevitably affected by changing the size of the ES induction zone,which can further change the energy input under the same electromagnetic parameters,the temperature rising effect and the bulging *** investigate this phenomenon,the effects of the radius of the induction zone on the thermal-force contribution ratio,the heating ability of ES and the temperature distribution were analyzed through an electromagnetic-thermal-structural finite element *** ensure that the results are applicable to RPECT,the thermal energy conversion ability and thermal-force roll crown control ability under different lengths of the induction zone were *** was found that whether the current density regulation mode or the current frequency regulation mode is adopted,the cases with 20 or 25 mm radius of the induction zone have the great thermal energy conversion ability and the good thermal-force roll crown control *** reasonable adjustment of the length of the induction zone can reduce the radius required for the maximum energy efficiency *** with the results of the simulation analysis,the optimization of ES based on the control ability maximization requirement is achieved,which provides the base for the design and configuration of ES in RPECT.

关键词： Roll profile electromagnetic control technology Electromagnetic stick Electromagnetic control roll Induction area Thermal-force driving

QFS-domains and Quasicontinuous Domains

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2015年第2期31卷 295-304页

作者： wen Feng ZHANG Xiao quan XU Department of Mathematics Sichuan University School of Mathematics and Computer Science Jiangxi Science & Technology Normal University Department of Mathematics Jiangxi Normal University

In this paper, we show that （1） for each QFS-domain L, L is an ωQFS-domain iff L has a countable base for the Scott topology; （2） the Scott-continuous retracts of QFS-domains are QFS- domains; （3） for a quasicontinuous domain L, L is Lawson compact iff L is a finitely generated upper set and for any x1, x2 ∈ L and finite G1, G2 C L with G1 〈〈 x1, G2 〈〈 x2, there is a finite subset F C L such that ↑ x1 x2 G2; （4） L is a QFS-d0main iff L is a quasicontinuous domain and given any finitely many pairs {（Fi, xi）： Fi is finite, xi ∈ L with Fi 〈〈 xi, 1 ≤i ≤n}, there is a quasi-finitely separating function 5 on L such that Fi 〈〈 δ（xi）〈〈 xi.

关键词： QFS-domain quasicontinuous domain Scott topology Lawson compact

Geometry of Rectangular Block Triangular Matrices

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2009年第12期25卷 2035-2054页

作者： Li Ping HUANG Su wen zou School of Mathematics and Computing Science Changsha University of Science and Technology Changsha 410076 P. R. China Liuzhou Senior High School Liuzhou 545006 P. R. China

Let D be any division ring, and let T（mi,ni,k） be the set of k × k （k ≥ 2） rectangular block triangular matrices over D. For A, B ∈ T（mi,ni,k）, if rank（A - B） = 1, then A and B are said to be adjacent and denoted by A -B. A map T ： T（mi,ni,k） -〉 T（mi,ni,k） is said to be an adjacency preserving map in both directions if A - B if and only if φ（A） φ（B）. Let G be the transformation group of all adjacency preserving bijections in both directions on T（mi,ni,k）. When m1,nk ≥ 2, we characterize the algebraic structure of G, and obtain the fundamental theorem of rectangular block triangular matrices over D.

关键词： geometry of matrices triangular matrix adjacency preserving maximal set

SCKF-STF-CN:a universal nonlinear filter for maneuver target tracking

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 678-686页

作者： quan-bo GE wen-bin LI Cheng-lin wen Institute of Information and Control Hangzhou Dianzi University Hangzhou 310018 China State Key Lab of lndustrial Control Technology Zhejiang University Hangzhou 310027 China

Square-root cubature Kalman filter (SCKF) is more effective for nonlinear state estimation than an unscented Kalman *** this paper,we study the design of nonlinear filters based on SCKF for the system with one step noise correlation and abrupt state ***,we give the SCKF that deals with the one step correlation between process and measurement noises,SCKF-CN in ***,we introduce the idea of a strong tracking filter to construct the adaptive square-root factor of the prediction error covariance with a fading factor,which makes SCKF-CN obtain outstanding tracking performance to the system with target maneuver or abrupt state ***,the tracking performance of SCKF is greatly improved.A universal nonlinear estimator is proposed,which can not only deal with the conventional nonlinear filter problem with high dimensionality and correlated noises,but also achieve an excellent strong tracking performance towards the abrupt change of target *** simulation examples with a bearings-only tracking system are illustrated to verify the efficiency of the proposed algorithms.

关键词： Nonlinear system Maneuver target tracking Correlated noises Square-root cubature Kalman filter (SCKF) Strong tracking filtering (STF)