期刊文献+
共找到10,077篇文章
< 1 2 250 >
每页显示 20 50 100
Uniformed model of networked control systems with long time delay 被引量:4
1
作者 Zhu Qixin Liu Hongli Hu Shousong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期385-390,共6页
Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network a... Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network among control system components. Two new concepts including long time delay and short time delay are proposed. The sensor is almost always clock driven. The controller or the actuator is either clock driven or event driven. Four possible driving modes of networked control systems are presented. The open loop mathematic models of networked control systems with long time delay are developed when the system is driven by anyone of the four different modes. The uniformed modeling method of networked control systems with long time delay is proposed. The simulation results are given in the end. 展开更多
关键词 networked control systems time delay model driving mode.
在线阅读 下载PDF
A new approach for time effect analysis of settlement for single pile based on virtual soil-pile model 被引量:9
2
作者 吴文兵 王奎华 +1 位作者 张智卿 CHIN Jian Leo 《Journal of Central South University》 SCIE EI CAS 2012年第9期2656-2662,共7页
A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil laye... A new approach is proposed to analyze the settlement behavior for single pile embedded in layered soils. Firstly, soil layers surrounding pile shaft are simulated by using distributed Voigt model, and finite soil layers under the pile end are assumed to be virtual soil-pile whose cross-section area is the same as that of the pile shaft. Then, by means of Laplace transform and impedance function transfer method to solve the static equilibrium equation of pile, the analytical solution of the displacement impedance fimction at the pile head is derived. Furthermore, the analytical solution of the settlement at the head of single pile is theoretically derived by virtue of convolution theorem. Based on these solutions, the influences of parameters of soil-pile system on the settlement behavior for single pile are analyzed. Also, comparison of the load-settlement response for two well-instrumented field tests in multilayered soils is given to demonstrate the effectiveness and accuracy of the proposed approach. It can be noted that the presented solution can be used to calculate the settlement of single pile for the preliminary design of pile foundation. 展开更多
关键词 SETTLEMENT time effect single pile virtual soil-pile model layered soil VISCOELASTICITY distributed Voigt model
在线阅读 下载PDF
Traffic condition estimation with pre-selection space time model 被引量:5
3
作者 DONG Hong-hui SUN Xiao-liang +2 位作者 JIA Li-min LI Hai-jian QIN Yong 《Journal of Central South University》 SCIE EI CAS 2012年第1期206-212,共7页
A pre-selection space time model was proposed to estimate the traffic condition at poor-data-detector,especially non-detector locations.The space time model is better to integrate the spatial and temporal information ... A pre-selection space time model was proposed to estimate the traffic condition at poor-data-detector,especially non-detector locations.The space time model is better to integrate the spatial and temporal information comprehensibly.Firstly,the influencing factors of the "cause nodes" were studied,and then the pre-selection "cause nodes" procedure which utilizes the Pearson correlation coefficient to evaluate the relevancy of the traffic data was introduced.Finally,only the most relevant data were collected to compose the space time model.The experimental results with the actual data demonstrate that the model performs better than other three models. 展开更多
关键词 traffic condition ESTIMATION space time model pre-selection
在线阅读 下载PDF
Infinitesimal dividing modeling method for dual suppliers inventory model with random lead times 被引量:2
4
作者 Ji Pengcheng Song Shiji Wu Cheng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期527-536,共10页
As one of the basic inventory cost models, the (Q, τ)inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time de... As one of the basic inventory cost models, the (Q, τ)inventory cost model of dual suppliers with random procurement lead time is mostly formulated by using the concepts of "effective lead time" and "lead time demand", which may lead to an imprecise inventory cost. Through the real-time statistic of the inventory quantities, this paper considers the precise (Q, τ) inventory cost model of dual supplier procurement by using an infinitesimal dividing method. The traditional modeling method of the inventory cost for dual supplier procurement includes complex procedures. To reduce the complexity effectively, the presented method investigates the statistics properties in real-time of the inventory quantities with the application of the infinitesimal dividing method. It is proved that the optimal holding and shortage costs of dual supplier procurement are less than those of single supplier procurement respectively. With the assumption that both suppliers have the same distribution of lead times, the convexity of the cost function per unit time is proved. So the optimal solution can be easily obtained by applying the classical convex optimization methods. The numerical examples are given to verify the main conclusions. 展开更多
关键词 INVENTORY precise model random lead times dual supplier infinitesimal dividing method optimiza- tion.
在线阅读 下载PDF
Space station short-term mission planning using ontology modelling and time iteration 被引量:6
5
作者 Huijiao Bu Jin Zhang Yazhong Luo 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第2期407-421,共15页
This paper studies the problem of the space station short-term mission planning, which aims to allocate the executing time of missions effectively, schedule the corresponding resources reasonably and arrange the time ... This paper studies the problem of the space station short-term mission planning, which aims to allocate the executing time of missions effectively, schedule the corresponding resources reasonably and arrange the time of the astronauts properly. A domain model is developed by using the ontology theory to describe the concepts, constraints and relations of the planning domain formally, abstractly and normatively. A method based on time iteration is adopted to solve the short-term planning problem. Meanwhile, the resolving strategies are proposed to resolve different kinds of conflicts induced by the constraints of power, heat, resource, astronaut and relationship. The proposed approach is evaluated in a test case with fifteen missions, thirteen resources and three astronauts. The results show that the developed domain ontology model is reasonable, and the time iteration method using the proposed resolving strategies can successfully obtain the plan satisfying all considered constraints. 展开更多
关键词 space station mission planning ontology modelling time iteration
在线阅读 下载PDF
Iterative identification of discrete-time output-error model with time delay 被引量:3
6
作者 CHEN Feng-wei LIU Tao 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期647-654,共8页
The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function mod... The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function model parameters and time delay are alternately fixed to estimate each other.The instrumental variable technique is applied to guarantee consistent estimation against measurement noise.A noteworthy merit of the proposed method is that it can handle fractional time delay estimation,compared to existing methods commonly assuming that the time delay is an integer multiple of the sampling interval.The identifiability analysis for time delay is addressed and correspondingly,some guidelines are provided for practical implementation of the proposed method.Numerical and experimental examples are presented to illustrate the effectiveness of the proposed method. 展开更多
关键词 system identification output-error model instrumental variable method time delay
在线阅读 下载PDF
Selection model of trip time for rural population 被引量:2
7
作者 冯忠祥 袁华智 +2 位作者 刘静 高璇 张卫华 《Journal of Central South University》 SCIE EI CAS 2013年第1期274-278,共5页
Referring to the 1 248 survey data of rural population in 14 provinces of China, the influencing factors of trip time choice were analyzed. Based on the basic theory of disaggregate model and its modelling method, nin... Referring to the 1 248 survey data of rural population in 14 provinces of China, the influencing factors of trip time choice were analyzed. Based on the basic theory of disaggregate model and its modelling method, nine grades were selected as the alternatives of trip time, the variables affecting time choice and the method getting their values were determined, and a multinomial logit (MNL) model was developed. Another 1 200 trip data of rural population were selected to testify the model's validity. The result shows that the maximum absolute error of each period between calculated value and statistic is 3.6%, so MNL model has high calculation accuracy. 展开更多
关键词 traffic planning rural population trip time disaggregate model multinominal logit (MNL) model
在线阅读 下载PDF
Dynamics of the HBV model with diffusion and time delay 被引量:2
8
作者 QIAO mei-hong,QI huan(Department of Control Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074) 《医用生物力学》 EI CAS CSCD 2009年第S1期117-118,共2页
Chronic hepatitis B infection is a major health problem,with approximately 350 million virus carriers worldwide.In Africa,about 30%-60% of children and 60%-100% of adults have
关键词 HBV time Dynamics of the HBV model with diffusion and time delay
在线阅读 下载PDF
Multi-factor high-order intuitionistic fuzzy timeseries forecasting model 被引量:1
9
作者 Ya'nan Wang Yingjie Lei +1 位作者 Yang Lei Xiaoshi Fan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第5期1054-1062,共9页
Fuzzy sets theory cannot describe the neutrality degreeof data, which has largely limited the objectivity of fuzzy time seriesin uncertain data forecasting. With this regard, a multi-factor highorderintuitionistic fuz... Fuzzy sets theory cannot describe the neutrality degreeof data, which has largely limited the objectivity of fuzzy time seriesin uncertain data forecasting. With this regard, a multi-factor highorderintuitionistic fuzzy time series forecasting model is built. Inthe new model, a fuzzy clustering algorithm is used to get unequalintervals, and a more objective technique for ascertaining membershipand non-membership functions of the intuitionistic fuzzy setis proposed. On these bases, forecast rules based on multidimensionalintuitionistic fuzzy modus ponens inference are established.Finally, contrast experiments on the daily mean temperature ofBeijing are carried out, which show that the novel model has aclear advantage of improving the forecast accuracy. 展开更多
关键词 multi-factor high-order intuitionistic fuzzy time series forecasting model intuitionistic fuzzy inference.
在线阅读 下载PDF
Performance analysis model for real-time Ethernet-based computer numerical control system 被引量:2
10
作者 万加富 李迪 +1 位作者 涂钰青 张春华 《Journal of Central South University》 SCIE EI CAS 2011年第5期1545-1553,共9页
In order to optimize the embedded system implementation for Ethernet-based computer numerical control (CNC) system, it is very necessary to establish the performance analysis model and further adopt the codesign met... In order to optimize the embedded system implementation for Ethernet-based computer numerical control (CNC) system, it is very necessary to establish the performance analysis model and further adopt the codesign method from the control, communication and computing perspectives. On the basis of analyzing real-time Ethemet, system architecture, time characteristic parameters of control-loop ere, a performance analysis model for real-time Ethemet-based CNC system was proposed, which is able to include the timing effects caused by the implementation platform in the simulation. The key for establishing the model is accomplished by designing the error analysis module and the controller nodes. Under the restraint of CPU resource and communication bandwidth, the experiment with a case study was conducted, and the results show that if the deadline miss ratio of data packets is 0.2%, then the percentage error is 1.105%. The proposed model can be used at several stages of CNC system development. 展开更多
关键词 computer numerical control (CNC) system real-time Ethemet time characteristic parameters performance analysis model manufacturing accuracy
在线阅读 下载PDF
Remaining useful life prediction based on nonlinear random coefficient regression model with fusing failure time data 被引量:4
11
作者 WANG Fengfei TANG Shengjin +3 位作者 SUN Xiaoyan LI Liang YU Chuanqiang SI Xiaosheng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第1期247-258,共12页
Remaining useful life(RUL) prediction is one of the most crucial elements in prognostics and health management(PHM). Aiming at the imperfect prior information, this paper proposes an RUL prediction method based on a n... Remaining useful life(RUL) prediction is one of the most crucial elements in prognostics and health management(PHM). Aiming at the imperfect prior information, this paper proposes an RUL prediction method based on a nonlinear random coefficient regression(RCR) model with fusing failure time data.Firstly, some interesting natures of parameters estimation based on the nonlinear RCR model are given. Based on these natures,the failure time data can be fused as the prior information reasonably. Specifically, the fixed parameters are calculated by the field degradation data of the evaluated equipment and the prior information of random coefficient is estimated with fusing the failure time data of congeneric equipment. Then, the prior information of the random coefficient is updated online under the Bayesian framework, the probability density function(PDF) of the RUL with considering the limitation of the failure threshold is performed. Finally, two case studies are used for experimental verification. Compared with the traditional Bayesian method, the proposed method can effectively reduce the influence of imperfect prior information and improve the accuracy of RUL prediction. 展开更多
关键词 remaining useful life(RUL)prediction imperfect prior information failure time data NONLINEAR random coefficient regression(RCR)model
在线阅读 下载PDF
On modeling approach for embedded real-time software simulation testing 被引量:6
12
作者 Yin Yongfeng Liu Bin Zhong Deming Jiang Tongmin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第2期420-426,共7页
Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and emb... Modeling technology has been introduced into software testing field. However, how to carry through the testing modeling effectively is still a difficulty. Based on combination of simulation modeling technology and embedded real-time software testing method, the process of simulation testing modeling is studied first. And then, the supporting environment of simulation testing modeling is put forward. Furthermore, an approach of embedded real-time software simulation testing modeling including modeling of cross-linked equipments of system under testing (SUT), test case, testing scheduling, and testing system service is brought forward. Finally, the formalized description and execution system of testing models are given, with which we can realize real-time, closed loop, mad automated system testing for embedded real-time software. 展开更多
关键词 embedded real-time software software testing testing modeling SIMULATION
在线阅读 下载PDF
Crop Yield Forecasted Model Based on Time Series Techniques
13
作者 Li Hong-ying Hou Yan-lin +1 位作者 Zhou Yong-juan Zhao Hui-ming 《Journal of Northeast Agricultural University(English Edition)》 CAS 2012年第1期73-77,共5页
Traditional studies on potential yield mainly referred to attainable yield: the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions wa... Traditional studies on potential yield mainly referred to attainable yield: the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions was defined in this paper, which was affected by advancement of science and technology. Based on the new concept of crop yield, the time series techniques relying on past yield data was employed to set up a forecasting model. The model was tested by using average grain yields of Liaoning Province in China from 1949 to 2005. The testing combined dynamic n-choosing and micro tendency rectification, and an average forecasting error was 1.24%. In the trend line of yield change, and then a yield turning point might occur, in which case the inflexion model was used to solve the problem of yield turn point. 展开更多
关键词 potential yield forecasting model time series technique yield turning point yield channel
在线阅读 下载PDF
基于病菌孢子捕捉和real-time PCR技术的田间空气中小麦白粉病菌孢子动态监测及病情估计模型研究 被引量:1
14
作者 王奥霖 商昭月 +8 位作者 张美惠 王贵 胡小平 徐飞 孙振宇 曹世勤 刘伟 范洁茹 周益林 《植物保护》 CAS CSCD 北大核心 2024年第2期49-56,72,共9页
利用Burkard定容式孢子捕捉器结合real-time PCR定量技术,分别对种植高抗、中感和高感白粉病小麦品种的田间空气中白粉病菌分生孢子浓度进行监测,结果表明,real-time PCR定量与传统的显微观察计数两种方法测得的孢子浓度呈显著正相关(P... 利用Burkard定容式孢子捕捉器结合real-time PCR定量技术,分别对种植高抗、中感和高感白粉病小麦品种的田间空气中白粉病菌分生孢子浓度进行监测,结果表明,real-time PCR定量与传统的显微观察计数两种方法测得的孢子浓度呈显著正相关(P≤0.01),且两种病菌孢子计数方法在同一抗性品种上监测到的孢子浓度动态相近。此外,两种方法测得的孢子浓度与各气象因子的相关性分析结果一致,空气中的白粉病菌孢子浓度主要与空气相对湿度显著正相关。在此基础上,利用两种方法测定的田间空气中白粉病菌孢子浓度分别建立了基于累积孢子浓度的田间病情估计模型。分析发现,基于两种孢子浓度测定方法建立的病情估计模型间无显著性差异,表明real-time PCR定量技术测定的孢子浓度在构建白粉病病情估计模型上具有一定可行性。该结果为real-time PCR定量技术与病菌孢子捕捉技术相结合用于小麦白粉病的监测和预测提供理论依据。 展开更多
关键词 小麦白粉病 病菌孢子捕捉 实时荧光定量PCR 病原菌监测 病情估计模型
在线阅读 下载PDF
Time-domain compressive dictionary of attributed scattering center model for sparse representation
15
作者 钟金荣 文贡坚 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期604-622,共19页
Parameter estimation of the attributed scattering center(ASC) model is significant for automatic target recognition(ATR). Sparse representation based parameter estimation methods have developed rapidly. Construction o... Parameter estimation of the attributed scattering center(ASC) model is significant for automatic target recognition(ATR). Sparse representation based parameter estimation methods have developed rapidly. Construction of the separable dictionary is a key issue for sparse representation technology. A compressive time-domain dictionary(TD) for ASC model is presented. Two-dimensional frequency domain responses of the ASC are produced and transformed into the time domain. Then these time domain responses are cutoff and stacked into vectors. These vectored time-domain responses are amalgamated to form the TD. Compared with the traditional frequency-domain dictionary(FD), the TD is a matrix that is quite spare and can markedly reduce the data size of the dictionary. Based on the basic TD construction method, we present four extended TD construction methods, which are available for different applications. In the experiments, the performance of the TD, including the basic model and the extended models, has been firstly analyzed in comparison with the FD. Secondly, an example of parameter estimation from SAR synthetic aperture radar(SAR) measurements of a target collected in an anechoic room is exhibited. Finally, a sparse image reconstruction example is from two apart apertures. Experimental results demonstrate the effectiveness and efficiency of the proposed TD. 展开更多
关键词 attributed scattering center model parameter estimation DICTIONARY time domain
在线阅读 下载PDF
Robust Stabilization of Nonlinear Time Delay Discrete-time Systems Based on T-S Model 被引量:1
16
作者 MI Yang JING Yuan-Wei 《自动化学报》 EI CSCD 北大核心 2006年第2期207-212,共6页
A robust stabilization problem is considered for time delay nonlinear discrete-time systems based on T-S fuzzy model. A necessary and sufficient condition for the existence of such controllers is given through Lyapuno... A robust stabilization problem is considered for time delay nonlinear discrete-time systems based on T-S fuzzy model. A necessary and sufficient condition for the existence of such controllers is given through Lyapunov stability theorem. And it is further shown that this condition is equivalent to the solvability of a certain linear matrix inequality, which can be solved easily by using the LMI toolbox of Matlab. At last, an illustrative example of truck-trailer is presented to show the feasibility and effectiveness of the proposed method. 展开更多
关键词 离散时间系统 模糊控制 线性矩阵不等式 T-S模糊模型 鲁棒稳定性
在线阅读 下载PDF
Discrete-time Direct Model Reference Adaptive Control: A Systematic Approach 被引量:1
17
作者 LI Jun-Ling XIE Xue-Jun 《自动化学报》 EI CSCD 北大核心 2007年第10期1048-1052,共5页
为直接模型引用的分离时间的系统,设计和分析的一个类,有规范的适应法律的适应控制(MRAC ) 被调查。我们责骂在输入和产量之间的 p 和 2 个关系性质上的分离时间的结论,和分离时间的交换词根 1 和 2。我们也建立分离时间的适应法律... 为直接模型引用的分离时间的系统,设计和分析的一个类,有规范的适应法律的适应控制(MRAC ) 被调查。我们责骂在输入和产量之间的 p 和 2 个关系性质上的分离时间的结论,和分离时间的交换词根 1 和 2。我们也建立分离时间的适应法律的性质,定义使正常化的信号,并且联系有在靠近环的系统的所有信号的信号。因此,分离时间的 MRAC 计划的稳定性和集中性质作为在连续时间的案例中以一种系统的方式严厉地被分析。 展开更多
关键词 离散时间系统 控制系统 系统方法 交换引理 模型参考自适应
在线阅读 下载PDF
A Systematic Analysis Approach to Discrete-time Indirect Model Reference Adaptive Control 被引量:1
18
作者 XIE Xue-Jun LI Jun-Ling 《自动化学报》 EI CSCD 北大核心 2007年第11期1170-1175,共6页
这份报纸论述间接模型引用的设计和分析有为分离时间的系统的一个类的规范的适应法律的适应控制(MRAC ) 。主要工作包括三部分。第一,构造工厂参数评价算法不仅拥有传统的评价算法的象那些的一样的性质而且在零避免分割的可能性。第二... 这份报纸论述间接模型引用的设计和分析有为分离时间的系统的一个类的规范的适应法律的适应控制(MRAC ) 。主要工作包括三部分。第一,构造工厂参数评价算法不仅拥有传统的评价算法的象那些的一样的性质而且在零避免分割的可能性。第二,由发现在工厂参数之间的关系,估计和控制器参数估计并且用工厂参数的性质估计,控制器参数估计的类似的性质也被建立。第三,基于关系,在使正常化之间的性质发信号并且在靠近环的系统并且在分离时间的系统上的一些重要数学工具上的所有信号作为在连续时间的盒子中,到分离间接 MRAC 计划的系统的稳定性和集中分析途径严厉地被开发。 展开更多
关键词 模型参考自适应控制 不连续时间系统 标准化适应定律 系统分析
在线阅读 下载PDF
An Improved H∞ Filter Design for Nonlinear System with Time-delay via T-S Fuzzy Models 被引量:1
19
作者 HUANG Sheng-Juan ZHANG Da-Qing HE Xi-Qin ZHANG Ning-Ning 《自动化学报》 EI CSCD 北大核心 2010年第10期1454-1459,共6页
关键词 非线性系统 自动化系统 研究 模糊性
在线阅读 下载PDF
Cyclic Reconfigurable Flow Shop under Different Configurations Modeling and Optimization Based on Timed Event Graph
20
作者 REN Si-Cheng XU De WANG Fang TAN Min 《自动化学报》 EI CSCD 北大核心 2006年第1期15-20,共6页
Based on the idea that modules are independent of machines, different combinations of modules and machines result in different configurations and the system performances differ under different configurations, a kind o... Based on the idea that modules are independent of machines, different combinations of modules and machines result in different configurations and the system performances differ under different configurations, a kind of cyclic reconfigurable flow shops are proposed for the new manufacturing paradigm-reconfigurable manufacturing system. The cyclic reconfigurable flow shop is modeled as a timed event graph. The optimal configuration is defined as the one under which the cyclic reconfigurable flow shop functions with the minimum cycle time and the minimum number of pallets. The optimal configuration, the minimum cycle time and the minimum number of pallets can be obtained in two steps. 展开更多
关键词 循环流程 制造业 时间事件 建模 优化设计
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部