检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

自动驾驶仿真测试场景生成技术研究进展

计算机工程与应用 2025年第1期61卷 59-79页

作者：孙乐乐黄松郑长友夏春艳阳真中国人民解放军陆军工程大学指挥与控制工程学院南京210007

自动驾驶系统已经成为汽车行业和计算机科学的前沿研究领域。为了确保自动驾驶系统的安全性和可靠性,对自动驾驶系统进行充分的测试是十分必要的,而仿真测试因其测试成本低、安全性高等优点,并且测试场景是自动驾驶仿真测试的关键,因此... 详细信息

自动驾驶系统已经成为汽车行业和计算机科学的前沿研究领域。为了确保自动驾驶系统的安全性和可靠性,对自动驾驶系统进行充分的测试是十分必要的,而仿真测试因其测试成本低、安全性高等优点,并且测试场景是自动驾驶仿真测试的关键,因此仿真测试场景生成是自动驾驶测试过程中不可或缺的环节。目前,已有大量学者致力于研究自动驾驶仿真测试,也有许多关于自动驾驶仿真测试的研究进展报告,但是针对于自动驾驶仿真测试场景生成的研究进展报告却寥寥无几。因此,对关于自动驾驶仿真测试场景的文献进行了全面调查,并对自动驾驶仿真测试的相关背景知识进行概述;通过调研国内外几十篇相关文献,按照自动驾驶系统的模块进行归纳总结,对现有仿真测试场景生成方法进行详细分类阐述;通过调研目前主流的仿真测试工具,对现有仿真测试工具进行分析归纳;分析了自动驾驶仿真测试领域面临的挑战和未来展望。

关键词：自动驾驶仿真测试测试场景整车测试仿真测试工具

维普期刊数据库

Parametric Resonance Analyses for Spar Platform in Irregular Waves

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2018年第2期32卷 236-244页

作者： yang He-zhen XU Pei-ji School of Engineering University of GlasgowGlasgow G128QQUnited Kingdom School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The parametric instability of a spar platform in irregular waves is analyzed. Parametric resonance is a phenomenon that may occur when a mechanical system parameter varies over time. When it occurs, a spar platform will have excessive pitch motion and may capsize. Therefore, avoiding parametric resonance is an important design requirement. The traditional methodology includes only a prediction of the Mathieu stability with harmonic excitation in regular waves. However, real sea conditions are irregular, and it has been observed that parametric resonance also occurs in non-harmonic excitations. Thus, it is imperative to predict the parametric resonance of a spar platform in irregular waves. A Hill equation is derived in this work, which can be used to analyze the parametric resonance under multi-frequency excitations. The derived Hill equation for predicting the instability of a spar can include non-harmonic excitation and random phases. The stability charts for multi-frequency excitation in irregular waves are given and compared with that for single frequency excitation in regular waves. Simulations of the pitch dynamic responses are carried out to check the stability. Three-dimensional stability charts with various damping coefficients for irregular waves are also investigated. The results show that the stability property in irregular waves has notable differences compared with that in case of regular waves. In addition, using the Hill equation to obtain the stability chart is an effective method to predict the parametric instability of spar platforms. Moreover, some suggestions for designing spar platforms to avoid parametric resonance are presented, such as increasing the damping coefficient, using an appropriate RAO and increasing the metacentric height.

关键词： spar platform instability parametric resonance Mathieu equation irregular waves dynamic responses

维普期刊数据库

Hybrid Laser Ablation and Chemical Modification for Fast Fabrication of Bio-inspired Super-hydrophobic Surface with Excellent Self-cleaning,Stability and Corrosion Resistance

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2019年第1期16卷 13-26页

作者： zhen yang Xianping Liu Yanling Tian Key Laboratory of Mechanism Theory and Equipment Design Ministry of EducationTianjin UniversityTianjin 300350China School of Engineering University of WarwickCoventry CV4 7ALUK

Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces,the issue is that the initial laser treated metallic surfaces show super-hydrophilic *** will take a long period to reach super-hydrophobic state under ambient *** is reported that these super-hydrophobic surfaces could be easily damaged by thermal heating effect or interaction with other liquids,causing uncontrolled loss of *** this study,a stable super-hydrophobic aluminum surface was rapidly fab-ricated via the hybrid laser ablation and surface chemical modification of(heptadecafluoro-1,1,2,2-tetradecyl)triethoxysilane(AC-FAS).Surface morphology and chemistry were systematically investigated to explore the generation mechanism of *** water contact angle of the treated surfaces can reach up to 160.6°±1.5°with rolling angle of 3.0°±1.0°,exhibiting perfect self-cleaning capability,long-term stability,and excellent chemical stability in acidic as well as alkaline *** potentiodynamic polarization tests implied that the super-hydrophobic surfaces showed better anti-corrosion *** hybrid laser ablation and surface chemical modification are very time-saving and low-cost,which offers a rapid way for quantity production of super-hydrophobic surface on aluminum material.

关键词： bioinspiration nanosecond laser super-hydrophobic chemical stability corrosion resistance self-cleaning long-term stability

Structure and flow calculation of cake layer on microfiltration membranes

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 Environmental Sciences 2017年第6期29卷 95-101页

作者： Yadong Yu zhen yang Yuanyuan Duan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO2 Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

Submerged membrane bioreactors （SMBR） are widely used in wastewater treatment. The permeability of a membrane declines rapidly because of the formation of a cake layer on the membrane surface. In this paper, a multiple staining protocol was conducted to probe the four major foulants in the cake layer formed on a filtration membrane. Fluorescent images of the foulants were obtained using a confocal laser scanning microscope （CLSM）. The three dimensional structure of the cake layer was reconstructed, and the internal flow was calculated using computational fluid dynamics （CFD）. Simulation results agreed well with the experimental data on the permeability of the cake layer during filtration and showed better accuracy than the calculation by Kozeny-Carman method. B-D-Glucopyranose polysaccharides and proteins are the two main foulants with relatively large volume fractions, while a-D-glucopyranose polysaccharides and nucleic acids have relatively large specific surface areas. The fast growth of B-D-glucopyranose polysaccharides in the volume fraction is mainly responsible for the increase in cake volume fraction and the decrease in permeability. The specific area, or the aggregation/dispersion of foulants, is less important to its permeability compared to its volume fraction.

关键词： Membrane fouling CLSM Cake layer CFD Permeability

维普期刊数据库

Semantic separator learning and its applications in unsupervised Chinese text parsing

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2013年第1期7卷 55-68页

作者： Yuming WU Xiaodong LUO zhen yang Key Laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China China Telecom Corporation Limited Shanghai Branch Shanghai 200120 China Shanghai Research Institute of China Telecom Corporation Limited Shanghai 200120 China

Grammar learning has been a bottleneck problem for a long time. In this paper, we propose a method of seman- tic separator learning, a special case of grammar learning. The method is based on the hypothesis that some classes of words, called semantic separators, split a sentence into sev- eral constituents. The semantic separators are represented by words together with their part-of-speech tags and other infor- mation so that rich semantic information can be involved. In the method, we first identify the semantic separators with the help of noun phrase boundaries, called subseparators. Next, the argument classes of the separators are learned from cor- pus by generalizing argument instances in a hypernym space. Finally, in order to evaluate the learned semantic separators, we use them in unsupervised Chinese text parsing. The exper- iments on a manually labeled test set show that the proposed method outperforms previous methods of unsupervised text parsing.

关键词： semantic separator separator learning unsuper vised text parsing

Simplification of I-Vector Extraction for Speaker Identification

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 Journal of Electronics 2016年第6期25卷 1121-1126页

作者： XU Longting yang zhen SUN Linhui Broadband Wireless Communication and Sensor Network Technology Key Lab Nanjing University of Posts and Telecommunications

The identity vector(i-vector) approach has been the state-of-the-art for text-independent speaker recognition, both identification and verification in recent years. An i-vector is a low-dimensional vector in the socalled total variability space represented with a thin and tall rectangular matrix. This paper introduces a novel algorithm to improve the computational and memory requirements for the application. In our method, the series of symmetric matrices can be represented by diagonal expression,sharing the same dictionary, which to some extent is analogous to eigen decomposition, and we name this algorithm Eigen decomposition like factorization(EDLF). Similar algorithms are listed for comparison, in the same condition,our method shows no disadvantages in identification accuracy.

关键词： Speaker identification Closed-set I-vector Symmetric matrix factorization

A New Type of Bistable Switching in Two-Dimensional Nonlinear Optical Superlattices

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第2期13卷 109-112页

作者： WANG zhen-lin yang zhen-ju MIN Nai-ben National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093

we investigate theoretically optical responsc in a two-dimensional optical superlattice with Kerr-type *** ind that in addition to the bistability reported in ***.71(1993)1003 by Xu et,al.,a new type of bista ble switching behavior *** bistability is based on the occurrence of the stop gap in the lincar spectraand the nonlinear mechanism on it,which makes switching between transmitting and non-transmitting states achievable.

关键词： Nonlinear addition nonlinear

The Boundary States of the q-Deformed Supersymmetric t-J Model with a Boundary

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第10期36卷 405-412页

作者： yang Wen-Li zhen Yi Institute of Modern Physics Northwest University Xi''an 710069 China Physikalisches Institut der Universitat Bonn Nussallee 12 53115 Bonn Germany Institute of Modern Physics Northwest University Xi''an 710069 China

The q-deformed supersymmetric t J model on a semi-infinite lattice is diagonalized by using the level-one vertex operators of the quantum affine superalgebra Uq[sl(2|1)]. We give the bosonization of the boundary states.

关键词： quantum t-J model, bosonization, affine quantum algebra, boundary states

The Solution Construction of Heterotic Super-Liouville Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第12期36卷 679-684页

作者： yang Zhan-Ying zhen Yi Institute of Modern Physics Northwest University Xi''an 710069 China Institute of Modern Physics Northwest University Xi''an 710069 China

We investigate the heterotic super-Liouville model on the base of the basic Lie super-algebra Osp(1|2).Using the super extension of Leznov-Saveliev analysis and Drinfeld Sokolov linear system, we construct the explicit solution of the heterotic super-Liouville system in component form. We also show that the solutions are local and periodic by calculating the exchange relation of the solution. Finally starting from the action of heterotic super-Liou ville model, we obtain the conserved current and conserved charge which possessed the BR ST properties.

关键词： heterotic, super-Liouville, super-algebra, chiral, the highest weight, Drinfeld Sokolov construction