期刊文献+
共找到370篇文章
< 1 2 19 >
每页显示 20 50 100
Controlling Fusion of Majorana Fermions in One-Dimensional Systems by Zeeman Field
1
作者 邵陆兵 汪子丹 +3 位作者 沈瑞 盛利 王伯根 邢定钰 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第6期96-99,共4页
We propose the realization of Majorana fermions (MFs) on the edges of a two-dimensional topological insulator in the proximity with s-wave superconductors and in the presence of transverse exchange field h. It is sh... We propose the realization of Majorana fermions (MFs) on the edges of a two-dimensional topological insulator in the proximity with s-wave superconductors and in the presence of transverse exchange field h. It is shown that there appear a pair of MFs localized at two junctions and that a reverse in the direction of h can lead to permutation of two MFs. With decreasing h, the MF states can either be fused or form one Dirac fermion on the π-junctions, exhibiting a topological phase transition. This characteristic can be used to detect physical states of MFs when they are transformed into Dirac fermions MFs is also given. localized on the π-junction. A condition of decoupling two 展开更多
关键词 MF controlling Fusion of Majorana Fermions in One-Dimensional Systems by Zeeman Field
下载PDF
Artificial Neural Networks for Controlling the Temperature of Internally Cooled Turning Tools
2
作者 Frank Wardle Timothy Minton +4 位作者 Saiful Bin Che Ghani Paul Furstmann Martin Roeder Sebastian Richarz Fiona Sammler 《Modern Mechanical Engineering》 2013年第2期1-10,共10页
By eliminating the need for externally applied coolant, internally cooled turning tools offer potential health, safety and cost benefits in many types of machining operation. As coolant flow is completely controlled, ... By eliminating the need for externally applied coolant, internally cooled turning tools offer potential health, safety and cost benefits in many types of machining operation. As coolant flow is completely controlled, tool temperature measurement becomes a practical proposition and can be used to find and maintain the optimum machining conditions. This also requires an intelligent control system in the sense that it must be adaptable to different tool designs, work piece materials and machining conditions. In this paper, artificial neural networks (ANN) are assessed for their suitability to perform such a control function. Experimental data for both conventional tools used for dry machining and internally cooled tools is obtained and used to optimise the design of an ANN. A key finding is that both experimental scatter characteristic of turning and the range of machining conditions for which ANN control is required have a large effect on the optimum ANN design and the amount of data needed for its training. In this investigation, predictions of tool temperature with an optimised ANN were found to be within 5°C of measured values for operating temperatures of up to 258°C. It is therefore concluded that ANN’s are a viable option for in-process control of turning processes using internally controlled tools. 展开更多
关键词 Control Systems In-Process Control Artificial Neural Network Machine Tools
下载PDF
Experimental Investigation of Demand Controlled Ventilation Systems: A Suitable Alternative for Controlling Ventilation in Dwellings
3
作者 Victor Jose del Campo Diaz Jon Teres-Zubiaga Elena Ruiz Cerrillo 《Journal of Energy and Power Engineering》 2012年第10期1553-1559,共7页
Indoor CO2 concentration depends on the number of persons, their metabolic rates, other sources of indoor pollution, ventilation rate and ventilation efficiency. These factors are not considered by the Spanish technic... Indoor CO2 concentration depends on the number of persons, their metabolic rates, other sources of indoor pollution, ventilation rate and ventilation efficiency. These factors are not considered by the Spanish technical building code since ventilation is set only by a fixed air change rate. This paper aims to explore the possibilities of DCVS (demand controlled ventilation systems) to ensure adequate and sustainable ventilation. It is based on a research project carried out by the University of the Basque Country (EHU-UPV) and Euskadi Public Housing and Soil Join-Stock Company (VISESA): the living rooms of 90 dwellings were provided with DCVS, where CO2 sensors were used to dynamically control the ventilation rate. Tests were carried out using tracer gas techniques, with results showing the air age to be adequate at every point of the occupied zones and free of stagnant areas, therefore proving the system's effectiveness and rapid response, and its energy savings. 展开更多
关键词 DCVS (demand controlled ventilation systems) energy efficiency indoor air quality.
下载PDF
A Survey on Type-3 Fuzzy Logic Systems and Their Control Applications
4
作者 Oscar Castillo Fevrier Valdez +1 位作者 Patricia Melin Weiping Ding 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第8期1744-1756,共13页
In this paper,we offer a review of type-3 fuzzy logic systems and their applications in control.The main objective of this work is to observe and analyze in detail the applications in the control area using type-3 fuz... In this paper,we offer a review of type-3 fuzzy logic systems and their applications in control.The main objective of this work is to observe and analyze in detail the applications in the control area using type-3 fuzzy logic systems.In this case,we review their most important applications in control and other related topics with type-3 fuzzy systems.Intelligent algorithms have been receiving increasing attention in control and for this reason a review in this area is important.This paper reviews the main applications that make use of Intelligent Computing methods.Specifically,type-3 fuzzy logic systems.The aim of this research is to be able to appreciate,in detail,the applications in control systems and to point out the scientific trends in the use of Intelligent Computing techniques.This is done with the construction and visualization of bibliometric networks,developed with VosViewer Software,which it is a free Java-based program,mainly intended to be used for analyzing and visualizing bibliometric networks.With this tool,we can create maps of publications,authors,or journals based on a co-citation network or construct maps of keywords,countries based on a co-occurrence networks,research groups,etc. 展开更多
关键词 Applications control systems optimization REVIEW type-3 fuzzy logic.
下载PDF
Quantization and Event-Triggered Policy Design for Encrypted Networked Control
5
作者 Yongxia Shi Ehsan Nekouei 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期946-955,共10页
This paper proposes a novel event-driven encrypted control framework for linear networked control systems(NCSs),which relies on two modified uniform quantization policies,the Paillier cryptosystem,and an event-trigger... This paper proposes a novel event-driven encrypted control framework for linear networked control systems(NCSs),which relies on two modified uniform quantization policies,the Paillier cryptosystem,and an event-triggered strategy.Due to the fact that only integers can work in the Pailler cryptosystem,both the real-valued control gain and system state need to be first quantized before encryption.This is dramatically different from the existing quantized control methods,where only the quantization of a single value,e.g.,the control input or the system state,is considered.To handle this issue,static and dynamic quantization policies are presented,which achieve the desired integer conversions and guarantee asymptotic convergence of the quantized system state to the equilibrium.Then,the quantized system state is encrypted and sent to the controller when the triggering condition,specified by a state-based event-triggered strategy,is satisfied.By doing so,not only the security and confidentiality of data transmitted over the communication network are protected,but also the ciphertext expansion phenomenon can be relieved.Additionally,by tactfully designing the quantization sensitivities and triggering error,the proposed event-driven encrypted control framework ensures the asymptotic stability of the overall closedloop system.Finally,a simulation example of the secure motion control for an inverted pendulum cart system is presented to evaluate the effectiveness of the theoretical results. 展开更多
关键词 Cyber-security encrypted control event-triggered control(ETC) networked control systems(NCSs) semi-homomorphic encryption
下载PDF
Control Strategies for Digital Twin Systems
6
作者 Guo-Ping Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第1期170-180,共11页
With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies ... With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical applications.To make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples. 展开更多
关键词 Digital twin control systems fault tolerant control model tracking performance prediction performance retention
下载PDF
Generalized autoencoder-based fault detection method for traction systems with performance degradation
7
作者 Chao Cheng Wenyu Liu +1 位作者 Lu Di Shenquan Wang 《High-Speed Railway》 2024年第3期180-186,共7页
Fault diagnosis of traction systems is important for the safety operation of high-speed trains.Long-term operation of the trains will degrade the performance of systems,which decreases the fault detection accuracy.To ... Fault diagnosis of traction systems is important for the safety operation of high-speed trains.Long-term operation of the trains will degrade the performance of systems,which decreases the fault detection accuracy.To solve this problem,this paper proposes a fault detection method developed by a Generalized Autoencoder(GAE)for systems with performance degradation.The advantage of this method is that it can accurately detect faults when the traction system of high-speed trains is affected by performance degradation.Regardless of the probability distribution,it can handle any data,and the GAE has extremely high sensitivity in anomaly detection.Finally,the effectiveness of this method is verified through the Traction Drive Control System(TDCS)platform.At different performance degradation levels,our method’s experimental results are superior to traditional methods. 展开更多
关键词 Performance degradation Generalized autoencoder Fault detection Traction control systems High-speed trains
下载PDF
Neural Network-Powered License Plate Recognition System Design
8
作者 Sakib Hasan Md Nagib Mahfuz Sunny +1 位作者 Abdullah Al Nahian Mohammad Yasin 《Engineering(科研)》 2024年第9期284-300,共17页
The development of scientific inquiry and research has yielded numerous benefits in the realm of intelligent traffic control systems, particularly in the realm of automatic license plate recognition for vehicles. The ... The development of scientific inquiry and research has yielded numerous benefits in the realm of intelligent traffic control systems, particularly in the realm of automatic license plate recognition for vehicles. The design of license plate recognition algorithms has undergone digitalization through the utilization of neural networks. In contemporary times, there is a growing demand for vehicle surveillance due to the need for efficient vehicle processing and traffic management. The design, development, and implementation of a license plate recognition system hold significant social, economic, and academic importance. The study aims to present contemporary methodologies and empirical findings pertaining to automated license plate recognition. The primary focus of the automatic license plate recognition algorithm was on image extraction, character segmentation, and recognition. The task of character segmentation has been identified as the most challenging function based on my observations. The license plate recognition project that we designed demonstrated the effectiveness of this method across various observed conditions. Particularly in low-light environments, such as during periods of limited illumination or inclement weather characterized by precipitation. The method has been subjected to testing using a sample size of fifty images, resulting in a 100% accuracy rate. The findings of this study demonstrate the project’s ability to effectively determine the optimal outcomes of simulations. 展开更多
关键词 Intelligent Traffic Control Systems Automatic License Plate Recognition (ALPR) Neural Networks Vehicle Surveillance Traffic Management License Plate Recognition Algorithms Image Extraction Character Segmentation Character Recognition Low-Light Environments Inclement Weather Empirical Findings Algorithm Accuracy Simulation Outcomes DIGITALIZATION
下载PDF
ADAPTIVE PREDICTIVE CONTROL OF NEAR-SPACE VEHICLE USING FUNCTIONAL LINK NETWORK 被引量:3
9
作者 都延丽 吴庆宪 姜长生 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2010年第2期148-154,共7页
A novel nonlinear adaptive control method is presented for a near-space hypersonic vehicle (NHV) in the presence of strong uncertainties and disturbances. The control law consists of the optimal generalized predicti... A novel nonlinear adaptive control method is presented for a near-space hypersonic vehicle (NHV) in the presence of strong uncertainties and disturbances. The control law consists of the optimal generalized predictive controller (OGPC) and the functional link network (FLN) direct adaptive law. OGPC is a continuous-time nonlinear predictive control law. The FLN adaptive law is used to offset the unknown uncertainties and disturbances in a flight through the online learning. The learning process does not need any offline training phase. The stability analyses of the NHV close-loop system are provided and it is proved that the system error and the weight learning error are uniformly ultimately hounded. Simulation results show the satisfactory performance of the con- troller for the attitude tracking. 展开更多
关键词 predictive control systems adaptive control systems UNCERTAINTY functional link network near-space vehicle
下载PDF
Kinematics simulation and application for machine tool based on multi-body system theory 被引量:2
10
作者 吴南星 孙庆鸿 +1 位作者 余冬玲 潘玉安 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期162-164,共3页
Based on the multi-body kinematics principle, the topological structure and restriction relation among parts of machine tool and 3D multi-body model are constructed, the kinematics simulation system of machine tool is... Based on the multi-body kinematics principle, the topological structure and restriction relation among parts of machine tool and 3D multi-body model are constructed, the kinematics simulation system of machine tool is developed. The designer can observe the movement and machining course of the whole machine tool and understand accurately the kinematics parameters of components such as position, velocity and acceleration. Also the designer can estimate the pose of components in the virtual circumstance and forecast accurately and correct problems which may appear during the design before the prototype is manufactured to assure the feasibility of design scheme, shorten period of product design and reduce product cost. The simulation system is used during the design of CK1416 high speed and precision numerical control lathe. The curves of ball screw angular velocity and carriage displacement agree well with the results of theoretical calculation and the constructed model is correct. 展开更多
关键词 FLOWCHARTING KINEMATICS Numerical control systems Virtual reality
下载PDF
NURBS CURVE INTERPOLATOR WITH ADAPTIVE ACCELERATION-DECELERATION CONTROL 被引量:2
11
作者 刘凯 赵东标 陆永华 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第4期241-247,共7页
The feedrate profile of non-uniform rational B-spline (NURBS) interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo-... The feedrate profile of non-uniform rational B-spline (NURBS) interpolation due to the contour errors is analyzed. A NURBS curve interpolator with adaptive acceleration-deceleration control is presented. In interpo- lation preprocessing, the sensitive zones of feedrate variations are processed with acceleration-deceleration control. By using the proposed algorithm, the machining accuracy is guaranteed and the feedrate is adaptively adjusted to he smoothed. The mechanical shock imposed in the servo system is avoided by the first and the second time derivatives of feedrates. A simulation of NURBS interpolation is given to demonstrate the validity and the effectiveness of the algorithm. The proposed interpolator can also be applied to the trajectory planning of the other parametric curves. 展开更多
关键词 numerical control systems INTERPOLATION adaptive algorithms NURBS curve interpolator adaptive acceleration and deceleration limited jerk
下载PDF
Speaker-independent speech recognition based on HMM state-restructuring method 被引量:2
12
作者 徐向华 朱杰 郭强 《Journal of Southeast University(English Edition)》 EI CAS 2004年第4期427-430,共4页
Based on confusions between hidden Markov model (HMM) states, a state-restructuring method was proposed. In the method, HMM states were restructured by sharing Gaussian components with their related states, and the re... Based on confusions between hidden Markov model (HMM) states, a state-restructuring method was proposed. In the method, HMM states were restructured by sharing Gaussian components with their related states, and the re-estimation to the increased-parameters, i.e., the inter-state weights, was derived under the expectation maximization (EM) framework. Experiments were performed on speaker-independent, large vocabulary, continuous Mandarin speech recognition. Experimental results showed that the state-restructured systems outperformed the baseline, and achieve significant improvement on recognition accuracy compared with the conventional parameter-increasing method. Such comparative results confirmed that the state-restructuring method was efficient. 展开更多
关键词 Classification (of information) Markov processes Parameter estimation Robustness (control systems) Vocabulary control
下载PDF
On the Motion of Controllable Mechanical Systems Having Variable Mass 被引量:1
13
作者 朱海平 吴惠彬 梅凤翔 《Journal of Beijing Institute of Technology》 EI CAS 1994年第2期122-130,共9页
The differential equations of motion of a comtlaint system with parameters and variable mass, of a system with variable mass and servo constraints and those for the control problem on the forced motion of constraint s... The differential equations of motion of a comtlaint system with parameters and variable mass, of a system with variable mass and servo constraints and those for the control problem on the forced motion of constraint systems with variable mass are given respectively. Finally, an example is presented. 展开更多
关键词 variable mass systems/controllable mechanical system servo constraint forced motion
下载PDF
ROBUST FAULT DIAGNOSIS FOR HELICOPTER FCS BASED ON LINEAR PARAMETERVARYING ADAPTIVE OBSERVER
14
作者 陈伟 姜斌 +1 位作者 张柯 杨浩 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2009年第4期288-294,共7页
Based on the linear parameter-varying (LPV) adaptive observer, the robust fault diagnosis for a class of LPV systems with external disturbances is studied. Since the flight control system (FCS) is nonlinear and ti... Based on the linear parameter-varying (LPV) adaptive observer, the robust fault diagnosis for a class of LPV systems with external disturbances is studied. Since the flight control system (FCS) is nonlinear and time-varying, the LPV technique is used for FCS. And then the adaptive fault estimation algorithm based on the LPV adaptive observer is proposed to estimate the fault. To minimize the effect of disturbances on the fault estimation, the H~ robust performance index is introduced to design the LPV adaptive fault diagnosis observer and the fault estimation algorithm. The result shows that the method has good estimation performance and is robust to external disturbances. The design method is presented in terms of linear matrix inequalities (LMIs). Finally, a helicopter LPV FCS model with the actuator fault is used to illustrate the effectiveness of the proposed method. 展开更多
关键词 fault diagnosis ROBUSTNESS flight control systems POLYTOPIC adaptive observer
下载PDF
EFFECTIVE DOUBLE LOOP CONTROL FOR A SQUARE WAVE BRUSHLESS DC MOTOR
15
作者 周波 李先祥 朱震莲 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第2期34+30-33,共5页
A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yie... A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yields a combination of desired characteristics including simplified control structure, small ripple torque, high speed accuracy, wide operating speed range, and fast dynamic response. Experimental results confirm excellent characteristics of the motor. 展开更多
关键词 synchronous motors speed control systems INVERTERS brushless DC motor double loop control square wave motors
下载PDF
CONTROL STRUCTURE AND IMPLEMENTATION OF CELL CONTROL SYSTEM
16
作者 任玲 王宁生 +1 位作者 叶文华 郭志平 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1997年第1期85-89,共5页
Cell control system(CCS) plays an important role in the hierarchical control structure of computer integrated manufacturing system(CIMS). It links up workshop controller and CAD/CAPP/CAM down to production facilities,... Cell control system(CCS) plays an important role in the hierarchical control structure of computer integrated manufacturing system(CIMS). It links up workshop controller and CAD/CAPP/CAM down to production facilities, and directly influences flexibility and efficiency of production. The hierarchical control structure and the key technical problems of the CCS are mainly described. The CCS controls the job schedule, the resource allocation and the operation of facilities in the manufacturing procedure according to the production plan and target coming from the workshop controller. The key technologies are discussed in this paper as follows: the application of client/server system structure in the production control and management; production planning and scheduling; the handling of exceptional incidents in production and the DNC interface control as well. 展开更多
关键词 production planning control systems cell controllers CIMS resources allocation
下载PDF
Multiresolution analysis over triangle meshes: method and data structure
17
作者 唐杰 张福炎 《Journal of Southeast University(English Edition)》 EI CAS 2004年第3期279-285,共7页
A robust and efficient algorithm is presented to build multiresolution models (MRMs) of arbitrary meshes without requirement of subdivision connectivity. To overcome the sampling difficulty of arbitrary meshes, edge c... A robust and efficient algorithm is presented to build multiresolution models (MRMs) of arbitrary meshes without requirement of subdivision connectivity. To overcome the sampling difficulty of arbitrary meshes, edge contraction and vertex expansion are used as downsampling and upsampling methods. Our MRMs of a mesh are composed of a base mesh and a series of edge split operations, which are organized as a directed graph. Each split operation encodes two parts of information. One is the modification to the mesh, and the other is the dependency relation among splits. Such organization ensures the efficiency and robustness of our MRM algorithm. Examples demonstrate the functionality of our method. 展开更多
关键词 ALGORITHMS Computer aided design Computer aided manufacturing Data structures GEOMETRY Mathematical models Robustness (control systems)
下载PDF
Time-stamped predictive functional control for networked control systems with random delays
18
作者 张奇智 张卫东 《Journal of Southeast University(English Edition)》 EI CAS 2005年第2期149-152,共4页
The random delays in a networked control system (NCS) degrade control performance and can even destabilize the control system.To deal with this problem,the time-stamped predictive functional control (PFC) algorithm is... The random delays in a networked control system (NCS) degrade control performance and can even destabilize the control system.To deal with this problem,the time-stamped predictive functional control (PFC) algorithm is proposed,which generalizes the standard PFC algorithm to networked control systems with random delays.The algorithm uses the time-stamp method to estimate the control delay,predicts the future outputs based on a discrete time delay state space model,and drives the control law that applies to an NCS from the idea of a PFC algorithm.A networked control system was constructed based on TrueTime simulator,with which the time-stamped PFC algorithm was compared with the standard PFC algorithm.The response curves show that the proposed algorithm has better control performance. 展开更多
关键词 networked control systems random delays predictive functional control industrial Ethernet
下载PDF
Criteria Selecting Knowledge Base in the FuzzyController of the Electrohydraulic Position Control System
19
作者 高建臣 吴平东 《Journal of Beijing Institute of Technology》 EI CAS 1998年第1期84-91,共8页
Aim To analyse the influence of knowledge base on the performance of the fuzzy controller of the electrohydraulic position control system,and to determine their selection cri- teria. Methods Experiments based on diffe... Aim To analyse the influence of knowledge base on the performance of the fuzzy controller of the electrohydraulic position control system,and to determine their selection cri- teria. Methods Experiments based on different membership functions,scaling factors and con-trol rules were done separately.The experiment results and the influence of different know- ledge base on the control performance were analysed in theory so that criteria of selcting knowledge base can be summarized correctly.Results Knowledge base,including membershipfunctions, scaling factors and control rules,has a crucial effect on the fuzzy control system.Suitably selected knowledge base can lead to good control performance of fuzzy control sys-tem. Conclusion Being symmetric,having an intersection ratio of 1 and satisfying width con- dition are three necessities for selecting membership functions.Selecting scaling factors dependson both the system requirement and a comprehensive analysis in the overshoot,oscillation, rising time and stability. Integrity and continuity must be guaranteed when determining control rules. 展开更多
关键词 fuzzy control knowledge base position control systems fuzzy sets
下载PDF
ANALYSIS AND SIMULATION OF CONTROL MIXER CONCEPT FOR A CONTROL RECONFIGURABLE AIRCRAFT
20
作者 李清 郭锁凤 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1995年第2期180-184,共5页
In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces wit... In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces with aerodynamic redundancy.This paper studies a control reconfiguration scheme based on Control Mixer Concept.A technique for the design of a control mixer for an aircraft with damaged surfaces/actuators using the pseudo-inverse is developed and applied.This paper discusses its applications and limitations based on linear analysis and computer simulation. 展开更多
关键词 flight control systems inverse matrices failuretolerant systems self-repairing systems control mixer aerodynamic redundancy
下载PDF
上一页 1 2 19 下一页 到第
使用帮助 返回顶部