检索结果-南通市图书馆

Weakly repelling fixed points and multiply-connected wandering domains of meromorphic functions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第2期49卷 267-276页

作者： QIU ling wu Shengjian LMAM School of Mathematical Sciences Peking University Beijing 100871 China LMAM School of Mathematical Sciences Peking University Beijing 100871 China

We consider the dynamics of a transcendental meromorphic function f(z) with only finitely many poles and prove that if / has only finitely many weakly repelling fixed points, then there is no multiply-connected wander... 详细信息

关键词： weakly repelling fixed point wandering domain.

Improvement of location methods based on RFID

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2013年第6期20卷 36-41页

作者： wu ling HUANG Li-ya Institute of Electronic Science and Engineering Nanjing University of Posts and Telecommunications

The most common location algorithms based on received signal strength （RSS） are location identification based on dynamic active radio frequency identification （LANDMARC） and virtual reference elimination （VIRE）. However, both the original algorithms suffer from some drawbacks. In this paper, several aspects of the two original algorithms have been modified to reduce the positioning errors. Firstly, Lagrange interpolation has been used instead of linear interpolation. Secondly, adaptive threshold has been introduced in the new algorithm. Thirdly, insert virtual reference tags to improve the location accuracy of the boundary of the sensing area. Finally, combine LANDMARC with VIRE to absorb both advantages. Compared with the original algorithms, on average, simulated results show that the modified algorithms can improve the location performance efficiently and achieve the goal of accurate positioning in indoor environment.

关键词： LANDMARC VIRE received signal strength indicator (RSSI) Lagrange adaptive threshold

Operations Research in the Blockchain Technology

在线全文

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2022年第2期10卷 401-422页

作者： Xu Wang ling-Yun wu IAM MADISNCMISAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Industrial Engineering Tsinghua UniversityBeijing 100084China

In the past decade,as a decentralized distributed database technology blockchain has developed rapidly at an unprecedented speed and been applied to a wide range of scenarios far beyond cryptocurrencies,for example,insurance,energy,risk management,and Internet of things(IoT).The blockchain technology combines the achievements from cryptography,computer science,economics,and operations research and has increasingly attracted attention from both academia and *** the operations research has been widely adopted in the blockchain technology,there is a lack of comprehensive survey on the operations research in blockchain-related *** order to fill the gap,we analyze the blockchain technology through the perspective of operations research and present a comprehensive review of the operations research problems from the aspects of security and stability,efficiency and performance,and resource *** paper aimed to help the relevant readers in the field of operations research find their own points of interest and conduct in-depth research on the blockchain technology,hoping to promote the rapid development and wider application of the blockchain technology in the near future.

关键词： Blockchain Operations research Security Efficiency Resource allocation

Evaluation of the efficacy of laser peripheral iridoplasty in reversing the darkroom provocative test result in Chinese patients with primary angle closure status post laser iridotomy

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

International Journal of Ophthalmology(English edition) 2015年第3期8卷 580-584页

作者： Ping Huang ling-ling wu Department of Ophthalmology Peking University Third Hospital Key Laboratory of Vision Loss and RestorationMinistry of Education

AIM: To investigate the efficacy and safety of krypton laser peripheral iridoplasty(LPIP) for Chinese patients with primary angle closure(PAC) or primary angle-closure glaucoma(PACG) status post laser iridotomy in reversing the positive results of the dark room provocative test(DRPT).METHODS: This study was prospective, noncomparative,interventional case series. Thirty-three patients(thirty-eight eyes) with PAC or PACG status post patent laser iridotomy and maintained normal intraocular pressure(IOP) but with positive DRPT results were enrolled. All the subjects were treated with krypton LPIP. DRPT was repeated after krypton LPIP. Results of DRPT were recorded. The visual acuity, IOP and gonioscopy were analyzed before and after krypton LPIP. A minimum time limit for follow-up was ***: Thirty-three patients(thirty-eight eyes)were followed for 17.7 ±8.37mo(range 7-41mo) after LPIP. Positive results of DRPT decreased from 38 eyes to9 eyes(23.7%) after LPIP. Peripheral anterior synechiae of angle in 34 of 38 eyes(89.5%) remained unchanged at dynamic gonioscopy throughout the follow-up period after ***: LPIP decreased positive rates of the DRPT significantly. The mechanism may be that LPIP minimized contact between the peripheral iris and trabecular meshwork, which is a key factor for developing peripheral anterior synechiae.

关键词： iridoplasty angle-closure glaucoma laser

Utilizing Probabilistic Linear Equations in Cube Attacks

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 Computer Science & Technology 2016年第2期31卷 317-325页

作者： Yuan Yao Bin Zhang Wen-ling wu Trusted Computing and Information Assurance Laboratory Institute of Software Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100190 China

Cube attacks, proposed by Dinur and Shamir at EUROCRYPT 2009, have shown huge power against stream ciphers. In the original cube attacks, a linear system of secret key bits is exploited for key recovery attacks. However, we find a number of equations claimed linear in previous literature actually nonlinear and not fit into the theoretical framework of cube attacks. Moreover, cube attacks are hard to apply if linear equations are rare. Therefore, it is of significance to make use of probabilistic linear equations, namely nonlinear superpolys that can be approximated by linear expressions effectively. In this paper, we suggest a way to test out and utilize these probabilistic linear equations, thus extending cube attacks to a wider scope. Concretely, we employ the standard parameter estimation approach and the sequential probability ratio test （SPRT） for linearity test in the preprocessing phase, and use maximum likelihood decoding （MLD） for solving the probabilistic linear equations in the online phase. As an application, we exhibit our new attack against 672 rounds of Trivium and reduce the number of key bits to search by 7.

关键词： cube attack sequential probability ratio test maximum likelihood decoding Trivium

Cooperative trajectory optimization of UAVs in approaching stage using feedback guidance methods

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

Defence Technology（防务技术） 2023年第6期24卷 361-381页

作者： Hao-ran Shi Fa-xing Lu ling wu College of Weaponry Engineering Naval University of EngineeringWuhan430033China

This paper mainly studies the problem of using UAVs to provide accurate remote target indication for hypersonic *** on the optimal trajectory trends and feedback guidance methods,a new cooperative control algorithm is proposed to optimize trajectories of multi-UAVs for target tracking in approaching *** on UAV kinematics and sensor performance models,optimal trajectory trends of UAVs are analyzed ***,feedback guidance methods are proposed under the optimal observation trends of UAVs in the approaching target stage,producing trajectories with far less computational complexity and performance very close to the best-known ***,the sufficient condition for the UAV to form the optimal observation configuration by the feedback guidance method is presented,which guarantees that the proposed method can optimize the observation trajectory of the UAV in approaching ***,the feedback guidance method is numerically *** results demonstrate that the estimation performance of the feedback guidance method is superior to the Lyapunov guidance vector field(LGVF)method and verify the effectiveness of the proposed ***,compared with the receding horizon optimization(RHO)method,the proposed method has the same optimization ability as the RHO method and better real-time performance.

关键词： Unmanned aerial vehicles(UAVs) Target tracking Trajectory optimization Receding horizon optimization(RHO) Feedback guidance method

Interfacial phase competition induced Kondo-like effect inmanganite-insulator composites

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2016年第6期11卷 129-133页

作者： ling-Fang Lin ling-Zhi wu Shuai Dong Department of Physics Southeast University Nanjing 211189 China School of Geography and Biological Information Nanjing University of Posts and Telecommunications Nanjing 210046 China

A Kondo-like effect, namely, the upturn of resistivity at low temperatures, is observed in perovskite manganite when nonmagnetic insulators are doped as secondary phase. In this paper, the low-temperature resistivity upturn effect has been argued to originate from interfacial magnetic phase reconstruction. Heisenberg spin lattices have been simulated using the Monte Carlo method to reveal phase competition around secondary phase boundary, namely, manganite-insulator boundary that behaves with a weak antiferromagnetic tendency. Moreover, the resistor network model based on double-exchange conductive mechanism reproduces the low-temperature resistivity upturn effect. Our work provides a reasonable physical mechanism to understand the novel transport behaviors in microstructures of correlated electron systems.

关键词： manganite Kondo-like effect manganite-insulator composites phase competition 75.47.Lx 75.47.Gk 73.63.-b

Changes in the Covariability of Surface Air Temperature and Precipitation over East Asia Associated with Climate Shift in the Late 1970s

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2014年第2期7卷 92-97页

作者： wu ling-Yun State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences

Variations in surface air temperature and precipitation are closely associated because of their thermodynamic relations. The climate shift in the late 1970s and associated changes in precipitation over East Asia have been well reported. However, how the covariability of surface air temperature and precipitation responds to the climate shift is not yet well understood. We used the observed mean（Tmean）, daily maximum（Tmax）, and minimum（Tmin） surface air temperatures and precipitation during the period of 1953–2000 to explore this issue. Results show that the covariability between Tmean and precipitation experienced remarkable changes over certain areas of East Asia after the climate shift with evident seasonal dependencies. In winter, after the climate shift significantly negative correlations occupied more areas over Mongolia and China. By contrast, in summer after the climate shift significantly negative correlations which existed over almost entire East Asia during the pre-shift period were mostly weakened with the exception of enhanced correlations over some small isolated areas. Changes in the covariability of Tmax and precipitation showed a similar spatial pattern to that of the Tmean, whereas the Tmin-precipitation covariability did not. In winter, after the climate shift positive correlations between Tmin and precipitation over southern China were largely weakened, while the areas with significantly negative correlations increased over Mongolia. In summer, changes in Tmin-precipitation covariability appeared to be a negative-positive-negative pattern from south to north over East Asia, with positive changes occurring in the Yangtze-Huai River valley and Korea and negative changes occurring over South China and Japan, and northern part of East Asia.

关键词： surface air temperature precipitation covariability climate shift

Dynamic resampling particle filter adaptive to changes in system model

在线全文

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2011年第4期9卷 584-588页

作者： ling wu Faxing LU Electronic Engineering College Naval University of Engineering Wuhan Hubei 430033 China

A dynamic resampling particle filter （DRPF）, integrated with scatteriflg and migrating operations, is proposed for the flexibility in nonlinear systems subject to changes in the system model without a considerable increase in computational cost. Under the change detection with the tracking error, the scattering and migration are alternatively adopted where the scattering can boost the diversity in the particle population when no change, or slow change occurs, while the migrating updates particles with new observations if the change comes abruptly. Simulation results validate the proposed PF as a promising alternative to the existing PFs.

关键词： Particle filter Bayesian estimation Change detection Resampling