检索结果-南通市图书馆

Adaptive PID controller based on Q-learning algorithm

在线全文

学校读者我要写书评

暂无评论

CAAI Transactions on Intelligence Technology 2018年第4期3卷 235-244页

作者： Qian Shi hak-keung lam Bo Xiao Shun-Hung Tsai Department of Informatics King’s College LondonBush HouseStrand Campus30 AldwychLondon WC2B 4BGUK Hamlyn Centre for Robotic Surgery Imperial College LondonLondon SW7 2AZUK Graduate Institute of Automation Technology National Taipei University of TechnologyTaipei 10608Taiwan

An adaptive proportional–integral–derivative(PID)controller based on Q-learning algorithm is proposed to balance the cart–pole system in simulation *** controller was trained using Q-learning algorithm and implemented the learned Q-tables to change the gains of linear PID controllers according to the state of the system during the control *** adaptive PID controller based on Q-learning algorithm was trained from a set of fixed initial positions and was able to balance the system starting from a series of initial positions that are different from the ones used in the training session,which achieved equivalent or even better performances in comparison with the conventional PID controller and the controller only uses Q-learning *** indicates the advantage of the adaptive PID controller based on Q-learning algorithm both in the generality of balancing the cart–pole system from a relatively wide range of initial positions and in the stabilisability of achieving smaller steady-state error.

关键词： Adaptive PID the controller

Playing Tic-Tac-Toe Using Genetic Neural Network with Double Transfer Functions

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 Intelligent Learning Systems and Applications 2011年第1期3卷 37-44页

作者： Sai Ho Ling hak keung lam 不详

Computational intelligence is a powerful tool for game development. In this paper, an algorithm of playing the game Tic-Tac-Toe with computational intelligence is developed. This algorithm is learned by a Neural Network with Double Transfer functions (NNDTF), which is trained by genetic algorithm (GA). In the NNDTF, the neuron has two transfer functions and exhibits a node-to-node relationship in the hidden layer that enhances the learning ability of the net-work. A Tic-Tac-Toe game is used to show that the NNDTF provide a better performance than the traditional neural network does.

关键词： Game Genetic Algorithm Neural Network

Compensated methods for networked control system with packet drops based on compressed sensing

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 2021年第6期32卷 1539-1556页

作者： FAN Ruifeng YIN Xunhe LIU Zhenfei lam hak keung Optoelectronic System Division North China Research Institute of Electro-OpticsChina Electronics Technology Group Corpora-tionBeijing 100015China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China Department of Informatics Kings College LondonLondon WC2R 2NDUK

Due to unreliable and bandwidth-limited characteristics of communication link in networked control systems,the realtime compensated methods for single-output systems and multioutput systems are proposed in this paper based on the compressed sensing(CS)theory and sliding window technique,by which the estimates of dropping data packets in the feedback channel are obtained and the performance degradation induced by packet drops is ***,in order to reduce the cumulative error caused by the algorithm,the compensated estimates for single-output systems are corrected via the regularization term;considering the process of single-packet transmission,a new sequential CS framework of sensor data streams is introduced to effectively compensate the dropping packet on single-channel of multi-output systems;in presence of the medium access constraints on multi-channel,the communication sequence for scheduling is coupled to the algorithm and the estimates of the multiple sensors for multi-output systems are obtained via the regularization *** results illustrate that the proposed methods perform well and receive satisfactory performance.

关键词： networked control systems packet drop compensated method compressed sensing(CS)

在线全文

学校读者我要写书评

暂无评论

带时延补偿的模糊广域阻尼控制分析与设计

系统工程与电子技术 2019年第10期41卷 2343-2351页

作者：尹逊和王伟 lam hak-keung 北京交通大学电子信息工程学院北京100044 伦敦国王学院信息系伦敦WC2R2LS

研究了存在网络通信时延的电力系统的广域阻尼控制问题。首先从理想传输情况出发,设计基于Mamdani方法的模糊逻辑广域阻尼控制器;然后考虑时延对控制效果的影响,在控制器中引入模糊输入,设计带时延补偿的模糊逻辑广域阻尼控制器。时延... 详细信息

研究了存在网络通信时延的电力系统的广域阻尼控制问题。首先从理想传输情况出发,设计基于Mamdani方法的模糊逻辑广域阻尼控制器;然后考虑时延对控制效果的影响,在控制器中引入模糊输入,设计带时延补偿的模糊逻辑广域阻尼控制器。时延补偿增加了控制器设计的复杂性,因此在保证系统性能无显著降低的条件下,对其模糊规则数进行简化。以4机2区域测试系统为例,利用Matlab/SimPowerSystem和TrueTime进行仿真分析,结果表明,与模糊逻辑广域阻尼控制器和传统的广域阻尼控制器相比,所设计的具有时延补偿的模糊逻辑广域阻尼控制器能有效地抑制时延对系统稳定性造成的影响。

关键词：低频振荡广域测量系统广域阻尼控制器模糊控制时延补偿

基于模型的网络控制系统设计:切换控制的平均驻留时间法

在线全文

学校读者我要写书评

暂无评论

系统工程与电子技术 2016年第8期38卷 1899-1908页

作者：赵顺利尹逊和魏学业 lam hak-keung 北京交通大学电子信息工程学院北京100044 伦敦大学国王学院信息系

利用平均驻留时间方法对基于模型的网络控制系统(model-based networked control system,MBNCS)进行了研究。MB-NCS由于能够在保证系统性能的前提下有效地减少系统对网络带宽的占用,自提出以来就受到了学者的广泛关注。首先总结了网络... 详细信息

利用平均驻留时间方法对基于模型的网络控制系统(model-based networked control system,MBNCS)进行了研究。MB-NCS由于能够在保证系统性能的前提下有效地减少系统对网络带宽的占用,自提出以来就受到了学者的广泛关注。首先总结了网络控制系统中常用的几种减少网络带宽占用的策略;其次,将基于模型的网络控制系统建模为切换系统,并在所建立的切换系统模型的基础上,利用平均驻留时间方法给出了使得此切换系统稳定的充分条件;最后,借助Lyapunov稳定性理论和线性矩阵不等式(linear matrix inequality,LMI)方法设计了使得此系统稳定的控制器,并且通过仿真验证了所提出方法的有效性。

关键词：基于模型的网络控制系统切换系统平均驻留时间 Lyapunov稳定性线性矩阵不等式

在线全文

学校读者我要写书评

暂无评论

基于脉冲切换控制的网络化控制系统设计

北京交通大学学报 2016年第2期40卷 8-14页

作者：赵顺利尹逊和魏学业 lam hak keung 北京交通大学电子信息工程学院北京100044 伦敦大学国王学院信息系

利用脉冲切换控制的平均驻留时间方法对基于模型的网络控制系统(Model-Based NetWorked Control System,MB-NCS)进行了研究.将基于模型的网络控制系统建模为一类脉冲切换系统;利用脉冲切换控制的平均驻留时间方法给出了使此脉冲切换系... 详细信息

利用脉冲切换控制的平均驻留时间方法对基于模型的网络控制系统(Model-Based NetWorked Control System,MB-NCS)进行了研究.将基于模型的网络控制系统建模为一类脉冲切换系统;利用脉冲切换控制的平均驻留时间方法给出了使此脉冲切换系统指数稳定的充分条件;借助Lyapunov稳定性理论和线性矩阵不等式方法设计了使此脉冲切换系统稳定的控制器,并且通过仿真验证了所提出的方法的有效性.

关键词：网络化控制系统脉冲切换控制平均驻留时间 Lyapunov稳定性线性矩阵不等式

Metabolites of Marine Fungus Aspergillus sp. Collected from Soft Coral Sarcophyton tortuosum

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第3期26卷 415-419页

作者： LI Hou-jin CAI Yong-tong CHEN Yun-yun lam Chi-keung LAN Wen-jian School of Chemistry and Chemical Engineering Sun Yat-sen University Guangzhou 510275 P. R. China School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 P. R. China

Fungus Aspergillus sp., which was isolated from soft coral Sarcophyton tortuosum, was cultured in the GPY medium containing glucose 10 g/L, peptone 5 g/L, yeast extract 2 g/L, sea water 1 L, at pH=7.5. Four com pounds, 3,6-diisobutyl-2（1H）-pyrazinone（1）, 3-isobutyl-6-（1-hydroxy-2-methylpropyl）-2（1H）-pyrazinone（2）, 3-methoxy-4-methyl-2,4-dien-pentanoic acid（3） and penicillic acid（4） were obtained from the AcOEt extract of the culture broth. Their structures were elucidated mainly based on the NMR, HR-EI-MS and X-ray single crystal diffraction experimental data. Compound 3 is a new compound. Compound 1 was previously proposed to be the tautomer of flavacol（3,6-diisobutylpyrazin-2-ol, 5）. However, the evaluation of the NMR and X-ray single crystal diffraction experimental data permitted us to propose that compound 1 existed as amide form instead oftautomers. Compound 1 is stable both in solution and crystal due to strong intermolecular hydrogen bonds. Incidentally supplying anthracenone to the GPY medium with a dose of 100 mg/L, the yield of penicillic acid（4） in the culture broth of the strain Aspergillus sp. was increased dramatically from 6 mg/L to 57 mg/L.

关键词： Aspergillus sp. 3,6-diisobutyl-2(1H)-pyrazinone Penicillic acid Flavacol

Bayesian meta-analysis of regional biomass factors for Quercus mongolica forests in South Korea

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2015年第4期26卷 875-885页

作者： Tzeng Yih lam Xiaodong Li Rae Hyun Kim Kyeong hak Lee Yeong Mo Son Division of Forest Management Department of Forest and Climate Change Korea Forest Research Institute57 Hoegiro Dongdaemun-gu Seoul 130-712 South Korea School of Forestry and Resource Conservation National Taiwan University

Indirect approaches to estimation of biomass factors are often applied to measure carbon flux in the forestry sector. An assumption underlying a country-level carbon stock estimate is the representativeness of these factors. Although intensive studies have been conducted to quantify biomass factors, each study typically covers a limited geographic area. The goal of this study was to employ a meta-analysis approach to develop regional bio- mass factors for Quercus mongolica forests in South Korea. The biomass factors of interest were biomass conversion and expansion factor （BCEF）, biomass expansion factor （BEF） and root-to-shoot ratio （RSR）. Our objectives were to select probability density functions （PDFs） that best fitted the three biomass factors and to quantify their means and uncertainties. A total of 12 scientific publications were selected as data sources based on a set of criteria. Fromthese publications we chose 52 study sites spread out across South Korea. The statistical model for the meta- analysis was a multilevel model with publication （data source） as the nesting factor specified under the Bayesian framework. Gamma, Log-normal and Weibull PDFs were evaluated. The Log-normal PDF yielded the best quanti- tative and qualitative fit for the three biomass factors. However, a poor fit of the PDF to the long right tail of observed BEF and RSR distributions was apparent. The median posterior estimates for means and 95 % credible intervals for BCEF, BEF and RSR across all 12 publica- tions were 1.016 （0.800-1.299）, 1.414 （1.304-1.560） and 0.260 （0.200-0.335）, respectively. The Log-normal PDF proved useful for estimating carbon stock of Q. mongolica forests on a regional scale and for uncertainty analysis based on Monte Carlo simulation.

关键词： Uncertainty analysis Monte Carlosimulation Bayesian hierarchical model Nestingstructure Biomass estimation

Acupuncture improves cognitive function A systematic review

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2013年第18期8卷 1673-1684页

作者： Mason Chin Pang Leung Ka keung Yip Chung Tsung lam Ka Shun lam Wai Lau Wing lam Yu Amethyst King Man Leung Kwok-fai So Department of Rehabilitation Sciences the Hong Kong Polytechnic University Cambridge Regional College Department of Anatomy and the State Key Laboratory of Brain and Cognitive Science the University of Hong Kong Pokfulam Hong Kong Special Administrative Region China GHM Institute of CNS Regeneration Jinan University

BACKGROUND： Acupuncture has been used as a treatment for cognitive impairment. OBJECTIVE： This review assesses clinical evidence for or against acupuncture as a treatment for cognitive impairment. This review also discusses the proposed mechanism（s） that could link acupuncture to improved cognitive function. METHODS： We searched the literature using PolyUone search from its inception to January 2013, with full text available and language limited to English. Levels of evidence were examined using Oxford Centre for Evidence-based Medicine-Levels of Evidence （March, 2009）. RESULTS： Twelve studies met the inclusion criteria： 3 human studies and 9 animal studies. Levels of evidence ranged from level lb to level 5. CONCLUSION： Most animal studies demonstrated a positive effect of acupuncture on cognitive impairment. However, the results of human studies were inconsistent. Further high-quality human studies with greater statistical power are needed to determine the effectiveness of acupuncture and an optimal protocol.

关键词： neural regeneration dementia acupuncture electroacupuncture learning cognitive cognition memory neuroregeneration