期刊文献+
共找到47篇文章
< 1 2 3 >
每页显示 20 50 100
老年腰椎手术患者下肢静脉血栓栓塞的时间-事件分析 被引量:6
1
作者 李阳 肖辉 +1 位作者 贺占坤 任洋良 《颈腰痛杂志》 2021年第1期8-11,共4页
目的以“时间-事件”的方式分析老年患者腰椎术后深静脉血栓(deep vein thrombosis,DVT)发生的情况,为腰椎术后DVT的防治提供数据支持。方法选择2013年9月~2019年6月在本院接受腰椎手术的428例患者作为研究对象,术后观察DVT发生人数、DV... 目的以“时间-事件”的方式分析老年患者腰椎术后深静脉血栓(deep vein thrombosis,DVT)发生的情况,为腰椎术后DVT的防治提供数据支持。方法选择2013年9月~2019年6月在本院接受腰椎手术的428例患者作为研究对象,术后观察DVT发生人数、DVT发生时间,以K-M曲线观察DVT发生的时间曲线,以Cox风险模型观察影响DVT发生的风险因素和DVT发生的生存函数。结果428例患者12周内共发生DVT 47例,发生率为10.98%,有典型临床症状与体征者16例,占34.04%。总的生存曲线表明,多数DVT事件发生于术后第1周,其次是术后第2周。单因素分析显示,DVT和非DVT患者的年龄、高血压、融合手术、手术时间、纤维蛋白原(fibrinogen,FIB)、D-二聚体(D-dimer,D-D)、低密度脂蛋白(low density lipoprotein,LDL)、总胆固醇(total cholesterol,TC)等临床指标存在统计学差异(P<0.05)。Cox回归模型结果显示,年龄、高血压、D-D是影响DVT发生的风险因素(P<0.05)。Cox回归生存函数显示,多数DVT事件发生在脊柱手术后的第1周和第2周。结论老年腰椎手术患者术后DVT事件多数发生于术后第1周和第2周,多数患者DVT以无症状类型存在,术后2周内应常规对患者进行下肢超声检查,以早期发现无症状型DVT并尽早干预,避免肺栓塞的发生。 展开更多
关键词 腰椎手术 下肢深静脉血栓 时间-事件分析
下载PDF
时间-事件结局证据合成中时间的效应修饰作用
2
作者 邹昕雨 李舍予 《中国循证医学杂志》 CSCD 北大核心 2024年第3期364-372,共9页
时间-事件结局是临床研究中重要的结局类型。在预后因素研究中进行时间-事件结局的效应分析时,时间的效应修饰作用的处理较为复杂,且容易被忽视。在一些临床场景中,时间的效应修饰作用可能对临床决策产生巨大影响。本文阐述了如何在时间... 时间-事件结局是临床研究中重要的结局类型。在预后因素研究中进行时间-事件结局的效应分析时,时间的效应修饰作用的处理较为复杂,且容易被忽视。在一些临床场景中,时间的效应修饰作用可能对临床决策产生巨大影响。本文阐述了如何在时间-事件结局存在时间的效应修饰作用时,使用恰当的方法进行证据合成。 展开更多
关键词 效应修饰 单个患者数据 META分析 时间-事件结局 时间依存性协变量 时间依存性系数
原文传递
试验序贯分析在时间-事件数据中的应用 被引量:1
3
作者 翁鸿 龚侃 +3 位作者 刘小平 李旭东 彭建平 曾宪涛 《中国循证医学杂志》 CSCD 2017年第2期239-242,共4页
Meta分析的样本量应该不低于单个随机对照试验的样本量,试验序贯分析(TSA)可提供期望信息量(RIS)以及界值来判断Meta分析的结论是否充足。而TSA软件只能进行二分类和连续型数据的分析,不能进行时间-事件数据的分析。本文主要介绍如何应... Meta分析的样本量应该不低于单个随机对照试验的样本量,试验序贯分析(TSA)可提供期望信息量(RIS)以及界值来判断Meta分析的结论是否充足。而TSA软件只能进行二分类和连续型数据的分析,不能进行时间-事件数据的分析。本文主要介绍如何应用TSA方法进行时间-事件数据的分析。 展开更多
关键词 试验序贯分析 META分析 时间-事件数据
原文传递
基于事件-时间驱动的远程控制方式下的双电机同步控制系统研究 被引量:1
4
作者 邵忠良 黄诚 《装备制造技术》 2013年第8期6-8,共3页
从双电动机的同步控制入手,在建立模型稳定控制同步以后,引入有延时的网络控制系统,对引入延时后的网络电机控制系统部分问题利用事件-时间驱动的远程控制方式,进行了研究、仿真和试验,提出一种有效、可应用的控制模型。
关键词 双电机 远程控制 事件-时间驱动
下载PDF
基于事件-时间关联模型的话题跟踪研究 被引量:3
5
作者 胡福玲 吴国文 赵臣升 《智能计算机与应用》 2016年第1期26-30,共5页
针对话题跟踪的任务是从时序新闻报道流中实时识别和挖掘相关于特定新闻话题的报道,本文提出一种事件-时间关联模型(EventTime Relation Model,ETRM)用来展开话题跟踪研究。ETRM将相关报道的时间属性引入向量空间模型,话题跟踪过程中将... 针对话题跟踪的任务是从时序新闻报道流中实时识别和挖掘相关于特定新闻话题的报道,本文提出一种事件-时间关联模型(EventTime Relation Model,ETRM)用来展开话题跟踪研究。ETRM将相关报道的时间属性引入向量空间模型,话题跟踪过程中将话题与相关报道相同特征项的时间相关度应用于相关性判定机制,同时基于时间的分布属性调整特征向量的权重分配,实现话题模型的自适应学习更新。实验采用DET曲线评测系统性能,结果显示相比于传统的话题模型,ETRM能够更加准确地追踪到话题焦点演化趋势,有效提高了话题跟踪系统的性能。 展开更多
关键词 话题跟踪 事件-时间关联模型 时间相关度 DET曲线
下载PDF
Icon memory research under different time pressures and icon quantities based on event-related potential 被引量:5
6
作者 牛亚峰 薛澄岐 +3 位作者 李雪松 李晶 王海燕 金涛 《Journal of Southeast University(English Edition)》 EI CAS 2014年第1期45-50,共6页
In order to obtain related brain electrical components and neural bases of physiology assessment of icon elements in a digital human-computer interface the modified sample-delay matching task experimental paradigm is ... In order to obtain related brain electrical components and neural bases of physiology assessment of icon elements in a digital human-computer interface the modified sample-delay matching task experimental paradigm is used under different time pressures 4 000 and 2 000 ms and different icon quantities three five and ten icons on icon memory based on event-related potential ERP technology.Experimental results demonstrate that P300 has significant volatility changes and the maximum amplitude around the middle line of the parietal area PZ and P200 has obvious volatility changes around the middle line of the frontal and central area FCZ during icon cognition.P300 and P200 amplitudes increase as tasks become more difficult.Thus P300 latency is positively correlated with task difficulty. ERP research on the characteristics of icon memory will be an important reference standard in guiding user neurocognitive behavior and physiology assessment on interface usability. 展开更多
关键词 time pressure icon quantity event-related potential ERP
下载PDF
儿童时间认知研究范式:困境与超越 被引量:2
7
作者 余习德 《心理发展与教育》 CSSCI 北大核心 2022年第5期749-760,共12页
西方实证主义导引下的儿童时间认知研究范式在取得丰硕成果的同时也渐入困境。以四种常见范式为突破口凝炼,困境是:(1)钟表时间认知范式能否涵盖儿童时间认知的全部内容;(2)各范式的使用与不同时间思维间能否有效适配;(3)共同量值系统(c... 西方实证主义导引下的儿童时间认知研究范式在取得丰硕成果的同时也渐入困境。以四种常见范式为突破口凝炼,困境是:(1)钟表时间认知范式能否涵盖儿童时间认知的全部内容;(2)各范式的使用与不同时间思维间能否有效适配;(3)共同量值系统(common magnitude system, CMS)能否从行为层面为儿童时间认知作出根源性解释;(4)在暂未发现成人时间认知特定脑机制的前提下,儿童时间认知脑机制的探索有多大的必要性与可行性等。诸困境折射出学界对儿童“经验”、“线性”时间的斜重;对“观念”、“周期性”时间的慢轻。中国时文化讲求以时间统摄空、物、人四者为一体,未来研究可将儿童时间认知归置于“时间-事件”背景之中,从具身情境、人际互动、时间言语习得与行为管控等方面超越。 展开更多
关键词 儿童时间认知 研究范式 时间三觉 时间-事件
原文传递
赢率-医学研究中一个直观而易于解释的综合结果(英文) 被引量:1
8
作者 hongyue wang jing peng +5 位作者 juila z.zheng bokai wang xiang lu chongshu chen xin m.tu changyong feng 《上海精神医学》 CSCD 2017年第1期55-60,共6页
对于医学研究中的多个结果,研究人员总是需要选择是否使用一个综合性结果(综合多个结果后所得的)作为主要结果。在本文中,我们回顾了治疗效果的一个新测量方式-赢率,它可以很容易地用于具有多个优先级结果的研究中。并且,我们在这块领... 对于医学研究中的多个结果,研究人员总是需要选择是否使用一个综合性结果(综合多个结果后所得的)作为主要结果。在本文中,我们回顾了治疗效果的一个新测量方式-赢率,它可以很容易地用于具有多个优先级结果的研究中。并且,我们在这块领域也提出了一些研究课题。 展开更多
关键词 时间-事件数据 生存函数 比例风险模型
下载PDF
时间概念化的转喻认知研究
9
作者 乔光东 《职业技术》 2016年第2期107-108,共2页
本文从时间-空间转喻、时间-事件转喻、时间-实物转喻、时间-动作转喻这四个方面来进行时间概念的转喻认知研究。本文指出既可以用空间或事件作为时间的转喻,也可以用时间作为空间或事件的转喻,但是人们常用实物或动作作为时间的转喻,... 本文从时间-空间转喻、时间-事件转喻、时间-实物转喻、时间-动作转喻这四个方面来进行时间概念的转喻认知研究。本文指出既可以用空间或事件作为时间的转喻,也可以用时间作为空间或事件的转喻,但是人们常用实物或动作作为时间的转喻,而鲜有用时间作为实物或动作的转喻。 展开更多
关键词 时间-空间转喻 时间-事件转喻 时间-实物转喻 时间-动作转喻
下载PDF
Effects of acute aerobic exercise on motor response inhibition:An ERP study using the stop-signal task 被引量:2
10
作者 Chien-Heng Chu Brandon L.Alderman +1 位作者 Gao-Xia Wei Yu-Kai Chang 《Journal of Sport and Health Science》 SCIE 2015年第1期73-81,共9页
Purpose: The purpose of this study was to determine the effects of acute exercise on motor response inhibition using both behavioral and electrophysiological approaches. Methods: The P3 and N1 event-related potenti... Purpose: The purpose of this study was to determine the effects of acute exercise on motor response inhibition using both behavioral and electrophysiological approaches. Methods: The P3 and N1 event-related potential (ERP) components were recorded while performing a stop-signal task in 21 college students following a moderately intense acute exercise bout for 30 min and a sedentary control session that involved reading. Results: Acute exercise induced a shorter stop signal response time (SSRT) as compared to control; however, the go response time (Go RT) remained unchanged. In examining the ERP data, acute exercise increased both P3 amplitude and latency but did not affect the N1 component. Conclusion: Acute exercise has a selective and beneficial effect on cognitive function, specifically affecting the motor response inhibition aspect of executive function. Furthermore, acute exercise predominately impacts later stages of information processing during motor response inhibition, which may lead to an increase in attentional resource allocation and confer the ability to successfully withhold a response to achieve motor response inhibition. 展开更多
关键词 COGNITION Executive function Inhibitory control NI P3
下载PDF
Complex patterns of precipitation and extreme events during 1951-2011 in Sichuan Basin, Southwestern China 被引量:4
11
作者 ZHOU Xiang-yang LEI Wen-juan 《Journal of Mountain Science》 SCIE CSCD 2018年第2期340-356,共17页
Sichuan Basin is located in southwestern China and affected by a complex water vapor (WV) sources. Here, the spatial and temporal patterns of precipitation and extreme events are investigated by six indices of World... Sichuan Basin is located in southwestern China and affected by a complex water vapor (WV) sources. Here, the spatial and temporal patterns of precipitation and extreme events are investigated by six indices of World Meteorology Organization Commission, including annual precipitation total (AP), maximum daily precipitation (Maxld), intensity of rainfall over 1 mm/d (IR1), maximum and mean consecutive dry days (Max CDD, Mean CDD) and coefficient of variance. Based on 24 daily precipitation time series from 1951 to 2o11, Mann-Kendall test is employed to quantify the significant level of these indices, from which the classification of precipitation change and its spatial patterns are obtained. Meanwhile, the probability distributions of these indices are identified by L-moment analysis and the Goodness-of-fit test, and the corresponding values are calculated by theoretical model at different return periods. The results reveal that the western basin displays normal drought: less AP and precipitation intensity while longer drought. The southern basin shows normal increase: larger AP and precipitation intensity but shorter CDD. However, in hilly region of the central basin and the transition zone between basin and mountains, precipitation changes abnormally: increasing both drought (one or both of Mean CDD and MaxCDD) and precipitation intensity (one or both of Maxld and trend of AP is. Probability IR1) no matter what the distribution models also demonstrate the complex patterns: a negative correlation between Maxld and Max CDD in the west (R2≥0.61) while a positive correlation in the east (R2≥0.41) at all return periods. These patterns are induced by the changes in WV sources and the layout of local terrain. The increase of WV in summer and decrease in spring leads to the heavier rainfall and longer drought respectively. The large heat island effect of the basin contributes to a lower temperature in transition zones and more precipitation in the downwind area. These results are helpful in reevaluating the risk regionally and making better decisions on water resources management and disaster prevention. 展开更多
关键词 Extreme precipitation events CLIMATECHANGE Sichuan Basin Trend analysis Probability distribution
原文传递
Characteristics of diurnal variations of warm-season precipitation over Xinjiang Province in China 被引量:1
12
作者 Jie Cao Shuping Ma +1 位作者 Weihua Yuan Zhiyan Wu 《Atmospheric and Oceanic Science Letters》 CSCD 2022年第2期13-18,共6页
Aimed at improving knowledge regarding the diurnal cycle of warm-season rainfall in northwestern China,this study investigated the diurnal variations of warm-season precipitation with different durations in Xinjiang,C... Aimed at improving knowledge regarding the diurnal cycle of warm-season rainfall in northwestern China,this study investigated the diurnal variations of warm-season precipitation with different durations in Xinjiang,China,using an hourly gauge–satellite merged precipitation product during 2008 to 2019.Results show noticeable diurnal variations with distinctive regional features.The primary peak is in the early evening.Rainfall events with duration less than 3 h occur more often across the whole of Xinjiang and contribute more than half of the precipitation amount over its northern and southern peripheries,while rainfall events with duration more than 7 h over the Tianshan Mountains are responsible for the primary peak in the diurnal variations of warm-season precipitation. 展开更多
关键词 Diurnal variation PRECIPITATION Rainfall duration Regional variation Arid and semi-arid regions
下载PDF
Monitoring Spatio-temporal Variance of an Extreme Heat Event Using Multiple-source Remote Sensing Data 被引量:3
13
作者 ZHU Shanyou LIU Yi +3 位作者 HUA Junwei ZHANG Guixin ZHOU Yang XIANG Jiamin 《Chinese Geographical Science》 SCIE CSCD 2018年第5期744-757,共14页
Extreme heat events have serious effects on human daily life. Accurately capturing the dynamic variance of extreme high-temperature distributions in a timely manner is the basis for analyzing the potential impacts of ... Extreme heat events have serious effects on human daily life. Accurately capturing the dynamic variance of extreme high-temperature distributions in a timely manner is the basis for analyzing the potential impacts of extreme heat, thereby informing risk prevention strategies. This paper demonstrates the potential application of multiple source remote sensing data in mapping and monitoring the extreme heat events that occurred on Aug. 8, 2013 in Jiangsu Province, China. In combination with MODIS products, the thermal sharpening(Ts HARP) method and a binary linear model are compared to downscale the original daytime FengY un 2 F(FY-2 F) land surface temperature(LST) imagery, with a temporal resolution of 60 min, from 5 km to 1 km. Using the meteorological measurement data from Nanjing station as the reference, the research then estimates the instantaneous air temperature by using an iterative computation based on the Surface Energy Balance Algorithm for Land(SEBAL), which is used to analyze the spatio-temporal air temperature variance. The results show that the root mean square error(RMSE) of the LST downscaled from the binary linear model is 1.30℃ compared to the synchronous MODIS LST, and on this basis the estimated air temperature has the RMSE of 1.78℃. The spatial and temporal distribution of air temperature variance at each geographical location from 06:30 to 18:30 can be accurately determined, and indicates that the high temperature gradually increases and expands from the city center. For the spatial distribution, the air temperature and the defined scorching temperature proportion index increase from northern to middle, to southern part of Jiangsu, and are slightly lower in the eastern area near the Yellow Sea. In terms of temporal characteristics, the percentage of area with air temperature above 37℃ in each city increase with time after 10:30 and reach the peak value at 14:30 or 15:30. Then, they decrease gradually, and the rising and falling trends become smaller from the southern cities to the northern regions. Moreover, there is a distinct positive relationship between the percentage of area above 37℃ and the population density. The above results show that the spatio-temporal distributions of heat waves and their influencing factors can be determined by combining multiple sources of remotely sensed image data. 展开更多
关键词 extreme heat events land surface temperature air temperature downscale remote sensing
下载PDF
The Amplitude-Duration Relation of Observed El Nio Events
14
作者 Wu Yu-Jie DUAN Wan-Suo 《Atmospheric and Oceanic Science Letters》 2012年第5期367-372,共6页
The authors demonstrate that the E1 Nifio events in the pre- and post-1976 periods show two ampli- tude-duration relations. One is that the stronger E1 Nifio events have longer durations, which is robust for the moder... The authors demonstrate that the E1 Nifio events in the pre- and post-1976 periods show two ampli- tude-duration relations. One is that the stronger E1 Nifio events have longer durations, which is robust for the moderate E1 Nifio events; the other is that the stronger E1 Nifio events have shorter durations but for strong E1 Nifio events. By estimating the sign and amplitude of the nonlinear dynamical heating (NDH) anomalies, the au- thors illustrate that the NDH anomalies are negligible for moderate E1 Nifio events but large for strong E1 Nifio events. In particular, the large NDH anomalies for strong E1 Nifio events are positive during the growth and mature phases, which favor warmer E1 Nifio events. During the decay phase, however, the negative NDH anomalies start to arise and become increasingly significant with the evolution of the E1 Nifio events, in which the negative NDH anomalies dampen the sea surface temperature anomalies (SSTA) and cause the E1 Nifio events to reach the SST normal state earlier. This pattern suggests that the nonlinearity tends to increase the intensities of strong E1 Nifio events and shorten their duration, which, together with the previous results showing a positive correlation between the strength of E1 Nifio events and the signifi- cance of the effect of nonlinear advection on the events (especially the suppression of nonlinearity on the SSTA during the decay phase), shows that the strong E1 Nifio events tend to have the amplitude-duration relation of the stronger E1 Nifio events with shorter durations. This result also lends support to the assertion that moderate E1 Nifio events possess the amplitude-duration relation of stronger E1 Nifio events with longer durations. 展开更多
关键词 climatic oscillation E1 Nifio events AMPLITUDE DURATION
下载PDF
The Empty Face of the Self-portrait: Time, Specter, and Event in The Fourth Portrait by Meng-Hung Chung
15
作者 Emily ShuHui Tsai 《Journal of Philosophy Study》 2016年第5期255-266,共12页
This short paper aims to critically analyze a contemporary Taiwan Residents film, The Fourth Portrait, directed by Meng-Hung Chung, from the perspective of Delenzian theories. In Deleuze's two books on cinema, the di... This short paper aims to critically analyze a contemporary Taiwan Residents film, The Fourth Portrait, directed by Meng-Hung Chung, from the perspective of Delenzian theories. In Deleuze's two books on cinema, the discussion of images demonstrates the entangled juxtaposition of the three levels: brain-thought, cinema-screen, and world-images that compose the cinematic consciousness. Through the interacted movement-images and time-images, the film unfolds the storyline within the aesthetic pleasure of poetic sentiment that gradually leads the audience to learn that a wandering boy, Hsiao-Hsiang, after the death of his father, has had several adventurous encounters that gradually expose the secrecy of his traumatic family: His birth mother has no decent job and his step-father has killed his own brother. This broken family has been haunted by the shared guilt and the undead memory as Derrida famously claims that hauntology precedes ontology. As the past coexists with the present, Deleuze analyzes the concept of I, with a central fracture in its pure form of the past demonstrating an ontological enigma that remains forever a secret. When the director uses the four portraits to indicate the four important events of this wandering boy, he deliberately leaves empty the fourth portrait, the self-portrait of the boy; it remains as an incomplete piece which symbolizes an enigma of his own life. It shows certain constitutive unnamable forces acting within the boy that seduces him forever to painfully misrecognize himself. 展开更多
关键词 cinematic consciousness specter TIME images REPETITION
下载PDF
Decadal Variations of Extreme Tropical Cyclones Influencing China during 1949-2009 被引量:4
16
作者 ZHAO Shan-Shan WANG Xiao-Ling 《Advances in Climate Change Research》 SCIE 2012年第3期121-127,共7页
Decadal variations of extreme tropical cyclones (TCs) influencing China were. investigated based on the tracks, landfall information, precipitation and wind data during 1949-2009. The extreme landfall date events ar... Decadal variations of extreme tropical cyclones (TCs) influencing China were. investigated based on the tracks, landfall information, precipitation and wind data during 1949-2009. The extreme landfall date events are less in the 1970s and 2000s. The number of extreme events of maximum wind speed and minimum pressure near TC's center reached the highest in the 2000s. The extreme rain duration events had the highest frequence in the 1970s, and the extreme strong wind duration events had the maximum frequence in the 1980s. The number of stations whereat the extreme maximum daily precipitation or process precipitation is observed, is the largest in the 1960s, and the number of stations whereat daily maximum wind speed events axe observed, is the largest in the 1980s. 展开更多
关键词 tropical cyclone extreme events decadal variation maximum landfall intensity landfall date maximum precipitation
下载PDF
The Post-Merger Performance: Evidence From Italy
17
作者 Fabrizio Rossi 《Chinese Business Review》 2012年第11期931-945,共15页
The objective of this paper is to investigate whether mergers create value for shareholders in both the short and long term. For this purpose, 120 announcements of mergers that were registered in Italy during the peri... The objective of this paper is to investigate whether mergers create value for shareholders in both the short and long term. For this purpose, 120 announcements of mergers that were registered in Italy during the period 1994-2006 among listed companies were examined. The short-term analysis was conducted using the event study methodology in order to estimate the cumulative abnormal returns (CARs) in the time window around the announcement date (-10, +10). In this work, the sample of 120 mergers was divided into two sub-samples: the first considers the mergers that were carried out in all sectors of the economy, and the second focuses only on bank mergers. From the results obtained it would appear that, while the sub-sample of all mergers registered a statistically significant value creation for the shareholders of both the bidder and target companies, values also confirmed by combined analysis, the second sub-sample registered negative values for bidder companies and positive values for target companies. Negative values also seem to be confirmed by the results of the combined analysis both at the date of announcement and throughout the entire period of observation. For the long-term analysis, the Buy and Hold Abnormal Returns (BHARs) methodology was used, with which it was possible to observe the returns for three years. In the 36 months following the merger, the portfolios showed a significant destruction of value 展开更多
关键词 post-merger performance Buy and Hold Abnormal Returns (BHARs) Cumulative Abnormal Returns(CARs) BANKS Italian stock market event study
下载PDF
TanDEM-X Autonomous Formation Flying System: Flight Results
18
作者 Jean-Sebastien Ardaens Denis Fischer 《Journal of Mechanics Engineering and Automation》 2012年第5期332-340,共9页
The TanDEM-X mission is a scientific and commercial Earth observation mission comprising two satellites flying in close formation. The formation maintenance can be advantageously performed by an onboard autonomous sys... The TanDEM-X mission is a scientific and commercial Earth observation mission comprising two satellites flying in close formation. The formation maintenance can be advantageously performed by an onboard autonomous system, which reduces the operational efforts, provides a shorter reaction time in case of contingencies and increases the control performance. The TanDEM-X Autonomous Formation Flying (TAFF) system has been developed for this purpose and is intended to replace the ground-based formation keeping activities during routine operations. TAFF has been activated for the first time in October 2010 for commissioning, during which the autonomous usage of thrusters was prohibited. Afterwards, a closed-loop campaign was successfully conducted in March 2011, demonstrating the capability of TAFF to maintain autonomously the formation. After a brief technical description of the system, the paper presents the key results gained during the commissioning phase and the closed-loop campaign, 展开更多
关键词 Spacecraft autonomy aerospace control closed-loop control navigation systems.
下载PDF
变采样网络控制系统的鲁棒控制 被引量:3
19
作者 薛燕 刘克 《计算机工程与应用》 CSCD 北大核心 2008年第27期240-244,共5页
对于线性时不变控制对象,在控制器和控制对象都采用时间-事件驱动时系统就变成便采样网络控制系统,当网络时延不确定时,在小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,使用李雅普诺夫方法和线性矩阵不... 对于线性时不变控制对象,在控制器和控制对象都采用时间-事件驱动时系统就变成便采样网络控制系统,当网络时延不确定时,在小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,使用李雅普诺夫方法和线性矩阵不等式研究了系统的鲁棒稳定性,并设计了鲁棒控制器,最后给出实例证明在鲁棒控制器的控制下系统稳定。 展开更多
关键词 网络控制系统 变采样 时间-事件驱动 鲁棒控制
下载PDF
变采样网络控制系统的最优保性能控制 被引量:5
20
作者 薛燕 刘克 《计算机工程与设计》 CSCD 北大核心 2009年第2期294-297,共4页
研究了一类不确定时延网络控制系统的最优保性能控制问题。针对线性时不变控制对象,控制器和控制对象采用时间-事件驱动,系统成为变采样网络控制系统,考虑在不确定时延小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制... 研究了一类不确定时延网络控制系统的最优保性能控制问题。针对线性时不变控制对象,控制器和控制对象采用时间-事件驱动,系统成为变采样网络控制系统,考虑在不确定时延小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,利用线性矩阵不等式研究了系统的保性能控制,并设计了保性能控制率和最优保性能控制率,最后给出实例表明在最优保性能控制率的控制下系统稳定。 展开更多
关键词 网络控制系统 变采样 时间-事件驱动 最优保性能控制 线性矩阵不等式 动态输出反馈
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部