检索结果-南通市图书馆

Stability analysis in an AVQ model of Internet congestion control algorithm

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 2012年第4期19卷 22-28页

作者： zhan zhen-qiu ZHU Jie XU Di Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper focuses on the local stability of a classical congestion control model in the Intemet, namely adaptive virtual queue （AVQ） algorithm with feedback delay. Firstly, necessary and sufficient stability conditions in terms of key tuning parameters are given, which can provide exact guidelines for setting system parameters. Furthermore, by computing the rightmost characteristic root, the optimal parameter configuration for AVQ is derived, which can guarantee superior stability performance. Finally, some simulation examples are given to illustrate the correctness of the theoretical analysis.

关键词： congestion control AVQ stability time delay system

Further results on local stability of LRC-RED algorithm in Internet

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 2012年第5期19卷 99-103页

作者： zhan zhen-qiu ZHU Jie SUN Yi-Jin Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper presents some further results on the local stability of a recently developed Intemet congestion control scheme, namely the loss ratio and rate control random early detection （LRC-RED） algorithm. Necessary and sufficient stability conditions in terms of key tuning parameters are derived, which can provide further guidelines for control gain selection. The numerical simulations are given to illustrate the correctness of the theoretical analysis.

关键词： congestion control LRC-RED stability time delay system

A new scheme for retrieving ocean surface salinity from simulated multi-angular SMOS brightness temperature

在线全文

学校读者我要写书评

暂无评论

热带海洋学报 2009年第5期28卷 11-17页

作者： WANG zhen-zhan YIN Xiao-bin Center for Space Science and Applied Research CAS Beijing 100190 China

The European Space Agency will launch the first salinity satellite for remotely sensing the global soil moisture and ocean salinity (SMOS) at a sun-synchronous orbit in 2009. One of the payloads on the satellite is a synthetic aperture microwave radiometer (MIRAS), which is an innovative instrument designed as a two-dimensional (2D) interferometer for acquiring brightness temperature (TB) at L-band (1.4 GHz). MIRAS allows measuring TB at a series of incidences for full polarizations. As the satellite travels, a given location within the 2D field of view is observed from different incidence angles. The authors develop a new scheme to retrieve the sea-surface salinity (SSS) from SMOS's TB at multi-incidence angles in a pixel, utilizing the properties of emissivity changing with incidence angles. All measurements of a given Stokes parameter in a pixel are first fitted to incidence angles in three order polynomial, and then the smoothed data are used for retrieving the SSS. The procedure will remove the random noise in TB greatly. Furthermore, the new method shows that the error in retrieved SSS is very sensitive to the system biases in the calibrated TB of the sensor, but the error in the retrieval is also a system bias, which can be corrected by post-launch validation. Therefore, this method may also serve as a means to evaluate the calibration precision in TB.

关键词： SMOS 盐分提取多入射角度温度亮度

Robotic Intracellular Electrochemical Sensing for Adherent Cells

在线全文

学校读者我要写书评

暂无评论

Cyborg and Bionic Systems 2022年第1期2022卷 75-86页

作者： Weikang Hu Yanmei Ma zhen zhan Danish Hussain Chengzhi Hu Shenzhen Key Laboratoryof Biomimetic Robotisand Intlligent Systems Department of Mechanicaland Enery EngineeringSouthern University of Science and TechnologyShenzhenChina Department of Mechatronics Engineering National University of Sciences and TechnologyIslamabadPakistan Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities Southern Universityof Science and TechnologyShenzhenChina

Nanopipette-based observation of intracellular biochemical processes is an important approach to revealing the intrinsic char acteristics and heterogeneity of cells for better investigation of disease progression or early disease ***,the manual operation needs a skilled operator and faces problems such as low throughput and poor *** paper proposes an automated nanopipette-based microoperation system for cell detection,*** nonovershoot positioning of the nanopipette tip in proximity to the cell of interest,cell approaching and proximity detection between nanopipette tip and cell surface,and cell penetration and detection of the intracellular reactive oxygen species(ROS).A robust focus algorithm based on the number of cell contours was proposed for adherent cells,which have sharp peaks while retaining *** automated detection of adherent cells was evaluated on human umbilical cord vein endothelial cells(HUVEC)and NIH/3T3 cells,which provided an average of 95.65%true-positive rate(TPR)and 7.59%false-positive rate(FPR)for in-plane cell *** three dimensional nonovershoot tip positioning of the nanopipette was achieved by template matching and evaluated under the interference of *** current feedback was employed for the proximity detection between the nanopipette tip and cell ***,cell penetration and electrochemical detection of ROS were demonstrated on human breast cancer cells and zebrafish embryo *** work provides a systematic approach for automated intracellular sensing for adherent cells,laying a solid foundation for high-throughput detection,diagnosis,and classification of different forms of biochemical reactions within single cells.

关键词： diagnosis proximity retaining

Dodecagonal bilayer graphene quasicrystal and its approximants

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

npj Computational Materials 2019年第1期5卷 73-82页

作者： Guodong Yu Zewen Wu zhen zhan Mikhail I.Katsnelson Shengjun Yuan Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan UniversityWuhan 430072China Institute for Molecules and Materials Radboud UniversityHeijendaalseweg 135NL-6525 AJ NijmegenNetherlands

Dodecagonal bilayer graphene quasicrystal has 12-fold rotational order but lacks translational symmetry which prevents the application of band *** this paper,we study the electronic and optical properties of graphene quasicrystal with large-scale tight-binding calculations involving more than ten million *** propose a series of periodic approximants which reproduce accurately the properties of quasicrystal within a finite unit *** utilizing the band-unfolding method on the smallest approximant with only 2702 atoms,the effective band structure of graphene quasicrystal is *** features,such as the emergence of new Dirac points(especially the mirrored ones),the band gap at M point and the Fermi velocity are all in agreement with recent *** properties of quasicrystal states are identified in the Landau level spectrum and optical ***,our results show that the lattice mismatch is the dominant factor determining the accuracy of layered *** proposed approximants can be used directly for other layered materials in honeycomb lattice,and the design principles can be applied for any quasi-periodic incommensurate structures.

关键词： theory. layered periodic

Multivariate error assessment of response time histories method for dynamic systems

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 Zhejiang University-Science A(Applied Physics & Engineering) 2012年第2期13卷 121-131页

作者： zhen-fei zhan Jie HU Yan FU Ren-Jye YANG Ying-hong PENG Jin QI School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Research and Innovation Center Ford Motor CompanyDearbornM148124USA

In this paper, an integrated validation method and process are developed for multivariate dynamic systems. The principal component analysis approach is used to address multivariate correlation and dimensionality reduction, the dynamic time warping and correlation coefficient are used for error assessment, and the subject matter experts (SMEs)’ opinions and principal component analysis coefficients are incorporated to provide the overall rating of the dynamic system. The proposed method and process are successfully demonstrated through a vehicle dynamic system problem.

关键词： Model validation Multivariate dynamic resnonses. Princioal component analvsis. Dvnamic time warping

Improved genetic algorithm based on reinforcement learning for electric vehicle front-end structure optimization design

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2024年第3期12卷 556-575页

作者： Feng-Yao Lyu zhen-Fei zhan Gui-Lin Zhou Ju Wang Jie Li Xin He Chongqing Jiaotong University Chongqing400074People’s Republic of China Changan Automobile Co.Ltd. Chongqing404100People’s Republic of China

The structural optimization of electric vehicles involves numerous design variables and constraints,making it a complex engineering optimization task over the past *** population-based evolutionary algorithms encounter issues such as converging to local optima and lacking population diversity when tackling such optimization ***,the solutions obtained for the optimization may be flawed or *** address these problems,an improved genetic algorithm(GA)based on reinforcement learning is proposed in this *** proposed method introduces a population delimitation method based on individual fitness *** population is divided into two parts:the excellent population and the ordinary population,and different selection and cross-mutation methods are applied to each part *** efficient crossover and mutation methods are then applied to the ordinary population to enhance the generation of excellent ***,the proposed approach replaces the traditional fixed crossover and mutation rates with a dynamic selection method based on reinforcement learning to enhance optimization efficiency.A markov decision process model is constructed based on GA environment in this *** population state determination method and reward method are designed for reinforcement learning in the GA environment,dynamically selecting the most appropriate genetic parameters based on the current state of the ***,the uncertainty in the manufacturing process is introduced into the optimization problem and the case study results demonstrate that the proposed reinforcement learning-based GA significantly outperforms other evolutionary algorithms when applied to solving the structural optimization of electric vehicles.

关键词： Structure optimization Genetic algorithm(GA) Q-learning

Fe-catalyzed regioselective Friedel–Crafts hydroxyalkylation of N-substituted glyoxylamide with indoles

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

Chinese Chemical Letters 2016年第1期27卷 41-46页

作者： Yang zheng Ren-Jun Li zhen zhan Yan Zhou Li Hai Yong Wu Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry West China School of Pharmacy Sichuan University

An efficient regioselective Friedel-Crafts hydroxyalkylation of N-substituted glyoxylamide with various indoles catalyzed by Lewis acids was developed. The reactions proceeded smoothly at room temperature and the 2-hydroxy-2-（1H-indol-3-yl）-N-substituted acetamide resulted from the reactions catalyzed by FeSO4 were synthesized in excellent yields （up to 93%）. While the bisindole compounds were obtained when FeCl3 was used as a catalyst in excellent yields （up to 92%）. A possible mechanism was proposed.

关键词： Friedel-Crafts hydroxyalkylation N-substituted glyoxylamide Indole Lewis acid 2-Hydroxy-2-(1H-indol-3-yl)-N substituted acetamide Bisindole compounds

EFFECTS OF A CLOUD FILTERING METHOD FOR FENGYUN-3C MICROWAVE HUMIDITY AND TEMPERATURE SOUNDER MEASUREMENTS OVER OCEAN ON RETRIEVALS OF TEMPERATURE AND HUMIDITY

在线全文

学校读者我要写书评

暂无评论

Journal of Tropical Meteorology 2018年第1期24卷 29-41页

作者： HE Qiu-rui WANG zhen-zhan HE Jie-ying Key Laboratory of Microwave Remote Sensing National Space Science CenterChinese Academy of SciencesBeijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

For Microwave Humidity and Temperature sounder(MWHTS) measurements over the ocean, a cloud filtering method is presented to filter out cloud-and precipitation-affected observations by analyzing the sensitivity of the simulated brightness temperatures of MWHTS to cloud liquid water, and using the root mean square error(RMSE)between observation and simulation in clear sky as a reference standard. The atmospheric temperature and humidity profiles are retrieved using MWHTS measurements with and without filtering by multiple linear regression(MLR),artificial neural networks(ANN) and one-dimensional variational(1DVAR) retrieval methods, respectively, and the effects of the filtering method on the retrieval accuracies are analyzed. The numerical results show that the filtering method can improve the retrieval accuracies of the MLR and the 1DVAR retrieval methods, but have little influence on that of the ANN. In addition, the dependencies of the retrieval methods upon the testing samples of brightness temperature are studied, and the results show that the 1DVAR retrieval method has great stability due to that the testing samples have great impact on the retrieval accuracies of the MLR and the ANN, but have little impact on that of the 1DVAR.

关键词： FY-3C/MWHTS cloud filtering method multiple linear regression artificial neural networks one-dimensional variational retrieval