检索结果-南通市图书馆

维普期刊数据库

Generalized fairing algorithm of parametric cubic splines

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第9期7卷 1572-1577页

作者： WANG yuan-jun cao yuan School of Mathematical Science Fudan University Shanghai 200433 China

Kjellander has reported an algorithm for fairing uniform parametric cubic splines. Poliakoff extended Kjellander’s algorithm to non-uniform case. However, they merely changed the bad point’s position, and neglected the smoothing of tangent at bad point. In this paper, we present a fairing algorithm that both changed point’s position and its corresponding tangent vector. The new algorithm possesses the minimum property of energy. We also proved Poliakoff’s fairing algorithm is a deduction of our fairing algorithm. Several fairing examples are given in this paper.

关键词： Curve fairing Tangent vector Energy optimization Cubic splines

维普期刊数据库

EXTRACTION OF ANTHRAQUINONE DERIVATIVES FROM RHUBARB RHIZOMES AND THEIR ANTIBACTERIAL TESTS

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2011年第2期4卷 127-132页

作者： yuan-CHENG cao yuan-DI ZHAO College of Life Science and Technology Huazhong University of Science and Technology Wuhan HuBeiP.R.China430074

Photometry was employed to study the optimum extraction conditions of anthraquinone derivatives from rhizomes of Rheum officinale Baill in this *** influences of extraction solvents(chloroform,benzene,ethanol,methanol,and glycerol),acid,and extraction time on the extraction yield were *** results indicate that,to the Rhubarb rhizomes powder with the average particle size 0.18 mm,the conditions of the extraction solvent composed by chloroform,glycerol,and sulfuric acid(20%)in the ratio of 4:1:1(v:v),the weight of dried Rhubarb to the solvent volume in the ratio of 1:12 ew:vT,extraction time of 110 min,the anthraquinone derivatives extraction could achieve the best *** the antibacterial tests showed the raw extraction products had the MIC(minimal inhibitory concentration)of 20μg=mL and 30μg=mL to Staphylococcus aureus and Escherichia coli,respectively.

关键词： Anthraquinone derivatives photometry optimum extraction conditions Rheum officinale Baill antibacterial

New self-calibration schemes for accelerometers in platform INS

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 Systems Engineering and Electronics 2015年第5期26卷 1032-1042页

作者： Hong Cai Anliang Li yuan cao College of Aerospace Science and Engineering National University of Defence Technology Science and Technology on Complex Land Systems Simulation Laboratory

To ensure success of precise navigation, it is necessary to carry out in-field calibration for the accelerometers in platform inertial navigation system(PINS) before a mission is *** continuous self-calibration methods are not fit for fast calibration of accelerometers because the platform misalignments have to be estimated precisely and the nonlinear coupling terms will affect accuracy. The multi-position methods with a "shape of motion" algorithm also have some existing disadvantages: High precision calibration results cannot be obtained when the accelerometer’s output data are used directly and it is difficult to optimize the calibration scheme. Focusing on this field, this paper proposes new fast self-calibration methods for the accelerometers of PINS. A data compression filter is employed to improve the accuracy of parameter estimation because it is impossible to obtain non-biased estimation for accelerometer parameters when using the "shape of motion" algorithm. Besides, continuous calibration schemes are designed and optimized by the genetic algorithm(GA) to improve the observability of parameters. Simulations prove that the proposed methods can estimate the accelerometer parameter more precisely than traditional continuous methods and multi-position methods, and they are more practical to deal with urgent situations than multi-position methods.

关键词： self-calibration accelerometers data compression genetic algorithm

Analysis of severe core damage accident progression for the heavy water reactor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2010年第4期21卷 251-256页

作者： TONG Lili yuan Kai yuan Jingtian cao Xuewu School of Mechanical Engineering Shanghai Jiao Tong University' Shanghai 200240 China

In this study,the severe accident progression analysis of generic Canadian deuterium uranium reactor 6 was preliminarily provided using an integrated severe accident analysis *** selected accident sequences were multiple steam generator tube rupture and large break loss-of-coolant accidents because these led to severe core damage with an assumed unavailability for several critical safety *** progressions of severe accident included a set of failed safety systems normally operated at full power,and initiative events led to primary heat transport system inventory blow-down or boil *** core heat-up and melting,steam generator response,fuel channel and calandria vessel failure were *** results showed that the progression of a severe core damage accident induced by steam generator tube rupture or large break loss-of-coolant accidents in a CANDU reactor was slow due to heat sinks in the calandria vessel and vault.

关键词：重水反应堆损坏事故蒸汽发生器堆芯 CANDU堆严重事故热传输系统事故分析

维普期刊数据库

The Investigation of Data Voting Algorithm for Train Air-Braking System Based on Multi-Classification SVM and ANFIS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 274-281页

作者： Juhan WANG Ying GAO yuan cao Tao TANG School of Electronics and Information Engineering Beijing Jiaotong University Graduate Department China Academy of Railway Science National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University

The pressure data of the train air braking system is of great significance to accurately evaluate its operation state. In order to overcome the influence of sensor fault on the pressure data of train air braking system, it is necessary to design a set of sensor fault-tolerant voting mechanism to ensure that in the case of a pressure sensor fault, the system can accurately identify and locate the position of the faulty sensor, and estimate the fault data according to other normal data. A fault-tolerant mechanism based on multi-classification support vector machine(SVM) and adaptive network-based fuzzy inference system(ANFIS) is introduced. Multi-classification SVM is used to identify and locate the system fault state, and ANFIS is used to estimate the real data of the fault sensor. After estimation, the system will compare the real data of the fault sensor with the ANFIS estimated data. If it is similar,the system will recognize that there is a false alarm and record it. Then the paper tests the whole mechanism based on the real data. The test shows that the system can identify the fault samples and reduce the occurrence of false alarms.

关键词： Support vector machines Fault diagnosis Pressure sensors Fuzzy logic Fault tolerance Adaptive systems Fault tolerant systems

Condition Monitoring for Railway Point Machines Based on Sound Analysis and Support Vector Machine

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 Journal of Electronics 2020年第4期29卷 786-792页

作者： SUN Yongkui cao yuan XIE Guo WEN Tao School of Electronic and Information Engineering Beijing Jiaotong University National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi'an University of Technology

Railway point machines(RPMS) are one of the key equipments in the railway system to switch different routes for the *** monitoring for RPMs is a vital measure to keep train operation safe and *** convenience and low cost into consideration, a novel intelligent condition monitoring method for RPMs based on sound analysis is ***-domain and frequency-domain features are obtained,and normalized using z-score standardization method to eliminate the influences of different *** particle swarm optimization(BPSO) is utilized to select the most significant discrimination feature *** effects of the selected optimal features are verified using Support vector machine(SVM), 1-Nearest neighbor(1 NN), Random forest(RF), and Naive Bayes(NB).Experiment results indicate SVM performs best on identification accuracy and computing cost compared with the other three *** identification accuracies on normal switching and reverse switching processes reach100% and 99.67%, respectively, indicating the feasibility of the proposed method.

关键词： Condition monitoring Sound analysis Railway point machines(RPMs) Binary particle swarm optimization(BPSO) Support vector machine(SVM)

Research on Virtual Coupled Train Control Method Based on GPC & VAPF

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 Journal of Electronics 2022年第5期31卷 897-905页

作者： cao yuan YANG Yaran MA Lianchuan WEN Jiakun State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University School of Electronic and Information Engineering Beijing Jiaotong University

Improving transportation efficiency is an eternal research hotspot in rail transit system. In recent years, the train operation control method based on virtual coupling has attracted the attention of many *** method of train coordination and anti-collision control is not only the key to realize the virtual coupling of train, but also the key to ensure the safety of train operation. Therefore, based on the existing research, a virtual coupled train dynamics model with nonlinear dynamics is established. Then, the parameters of the operation process model of the nonlinear virtual coupled train are identified by the recursive least squares method based on realtime data, which is applied to the variable parameter artificial potential field(VAPF) for parameter identification.A fusion controller based on feature-based generalized model prediction(GPC) and VAPF is used to control the virtual coupled train and prevent collision. Finally, the validity of the proposed method is verified by using real high-speed railway data.

关键词： recursive least squares method transportation vehicle dynamics train operation control transportation efficiency anti-collision control train operation safety feature-based generalized model prediction railway safety nonlinear dynamical systems fusion controller collision avoidance operation process model nonlinear virtual coupled train parameter identification nonlinear control systems variable parameter artificial potential field parameter estimation least squares approximations rail transit system virtual coupled train control predictive control train coordination collision prevention VAPF virtual coupled train dynamics railways high-speed railway data nonlinear dynamics virtual coupling GPC

Design and Analysis of Double One Out of Two with a Hot Standby Safety Redundant Structure

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 Journal of Electronics 2020年第3期29卷 586-594页

作者： WEN Jiakun cao yuan MA Lianchuan DU Siqi School of Electronic and Information Engineering Beijing Jiaotong University National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University

In the rail transit system, the running foundation of the computer control system is required to be highly reliable, available and safe. A redundant system structure of double one out of two with a hot standby applied to the safety computer platform of the train control system is proposed in this paper. Considering the common cause failure, fault diagnosis rate, repair rate and switching success rate, the Markovian approach is adopted for modeling four safety redundant structures,including two out of three, double one out of two, one out of two with a hot standby and double one out of two with a hot standby. The calculation of the failure rate and PFH values is carried out with MATLAB to evaluate the reliability, safety and influencing factors of each structure. The final conclusion is that double one out of two with a hot standby structure can be best in the aspect of both reliability and safety with appropriate DC and β parameters.

关键词： Markov model Safety redundant structure Reliability Safety Double one out of two with a hot standby

Coverage Adaptive Optimization Algorithm of Static-Sensor Networks for Target Discovery

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 Journal of Electronics 2019年第2期28卷 398-403页

作者： XIAO Shuo LI Tianxu TANG Chaogang cao yuan School of Computer Science and Technology China University of Mining and Technology School of Electronic and Information Engineering Beijing Jiaotong University

Sensor networks contain a large number of nodes that can perceive changes of external environment,which makes sensor networks particularly suitable for target tracking and discovery. In practical applications,once the sensor nodes are arranged, it is difficult to move them. We focus on analysing the target discovery ability of static-sensor networks. We divided the target into two kinds, one is persistent target and the other is instantaneous target. We investigate target discovery probability and discovery delay with different nodes density, sensing range and duty cycle. Energy saving is still the most important problem for the applications of sensor networks. Balancing target discovery capability and lifetime of the whole sensor network is necessary. Based on the theoretical analysis, we propose a coverage adaptive optimization algorithm that significantly prolongs the life of sensor networks. Simulation results show the advantage of coverage adaptive optimization algorithm over previous proposed methods.

关键词： Sensor networks Energy efficiency Network lifetime Discovery latency