检索结果-南通市图书馆

Minimax Q-learning design for H_(∞) control of linear discrete-time systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2022年第3期23卷 438-451页

作者： Xinxing LI Lele XI Wenzhong zha Zhihong PENg Information Science Academy China Electronics Technology Group CorporationBeijing 100086China School of Automation Beijing Institute of TechnologyBeijing 100081China Peng Cheng Laboratory Shenzhen 518052China

The H_(∞)control method is an effective approach for attenuating the effect of disturbances on practical systems, but it is difficult to obtain the H_(∞)controller due to the nonlinear Hamilton-Jacobi-Isaacs equation, even for linear systems. This study deals with the design of an H_(∞)controller for linear discrete-time systems. To solve the related game algebraic Riccati equation(gARE), a novel model-free minimax Q-learning method is developed, on the basis of an offline policy iteration algorithm, which is shown to be Newton’s method for solving the gARE. The proposed minimax Q-learning method, which employs off-policy reinforcement learning, learns the optimal control policies for the controller and the disturbance online, using only the state samples generated by the implemented behavior policies. Different from existing Q-learning methods, a novel gradient-based policy improvement scheme is proposed. We prove that the minimax Q-learning method converges to the saddle solution under initially admissible control policies and an appropriate positive learning rate, provided that certain persistence of excitation(PE)conditions are satisfied. In addition, the PE conditions can be easily met by choosing appropriate behavior policies containing certain excitation noises, without causing any excitation noise bias. In the simulation study, we apply the proposed minimax Q-learning method to design an H_(∞)load-frequency controller for an electrical power system generator that suffers from load disturbance, and the simulation results indicate that the obtained H_(∞)load-frequency controller has good disturbance rejection performance.

关键词： H_(∞)control Zero-sum dynamic game Reinforcement learning Adaptive dynamic programming Minimax Q-learning Policy iteration

LADYSMITH BLACK MAMBAZO From apartheid victims to grammy winners

在线全文

学校读者我要写书评

暂无评论

城市漫步（上海版、英文） 2015年第8期 46-47页

作者： ZOEY zha 不详

The South African a cappella group rocketed to global fame for their role on Paul Simon’s landmark *** have continued their outstanding performances in everything from the Lion King II to the 2010 FIFA World Cup in their home *** fourtime grammy Award winners will serenade Shanghai on August *** we met up,they took us through their journey so far.

关键词： continued grace FIFA

Uniqueness, scale, and resolution issues in groundwater model parameter identification

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

Water Science and Engineering 2015年第3期8卷 175-194页

作者： Tian-chyi J.Yeh De-qiang Mao Yuan-yuan zha Jet-chau Wen Li Wan Kuo-chin Hsu Cheng-haw Lee Department of Hydrology and Water Resources The University of Arizona Department of Resources Engineering National Cheng Kung University Department of geophysics Colorado School of Mines State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Safety Health and Environmental Engineering National Yunlin University of Science and Technology Research Center for Soil & Water Resources and Natural Disaster Prevention National Yunlin University of Science and Technology

This paper first visits uniqueness, scale, and resolution issues in groundwater flow forward modeling problems. It then makes the point that non-unique solutions to groundwater flow inverse problems arise from a lack of information necessary to make the problems well defined. Subsequently, it presents the necessary conditions for a well-defined inverse problem. They are full specifications of （1） flux boundaries and sources/sinks, and （2） heads everywhere in the domain at at least three times （one of which is t = 0）, with head change everywhere at those times being nonzero for transient flow. Numerical experiments are presented to corroborate the fact that, once the necessary conditions are met, the inverse problem has a unique solution. We also demonstrate that measurement noise, instability, and sensitivity are issues related to solution techniques rather than the inverse problems themselves. In addition, we show that a mathematically well-defined inverse problem, based on an equivalent homogeneous or a layered conceptual model, may yield physically incorrect and scenario-dependent parameter values. These issues are attributed to inconsistency between the scale of the head observed and that implied by these models. Such issues can be reduced only if a sufficiently large number of observation wells are used in the equivalent homogeneous domain or each layer. With a large number of wells, we then show that increase in parameterization can lead to a higher-resolution depiction of heterogeneity if an appropriate inverse methodology is used. Furthermore, we illustrate that, using the same number of wells, a highly parameterized model in conjunction with hydraulic tomography can yield better characterization of the aquifer and minimize the scale and scenario-dependent problems. Lastly, benefits of the highly parameterized model and hydraulic tomography are tested according to their ability to improve predictions of aquifer responses induced by independent stresses not u

关键词： Uniqueness Scale Resolution Forward and inverse problems Hydraulic tomography

How Shanghmi is Evolving Through Urban Innovation

在线全文

学校读者我要写书评

暂无评论

城市漫步（上海版、英文） 2016年第3期 52-63页

作者： Marianna Cerini Andrew Chin Zoey zha 不详

Cities weren't always plann *** conglomera tes around the world would expand and evolve,infrast rue tures growing out of n ecessi ty and by impr vised met *** new being layered on top of the *** were exceptions,of cou... 详细信息

关键词： Urban evolve Beijing.

盛唐英灵交往之遗踪--由《刘复墓志》看以王昌龄为中心的天宝丹阳诗人群

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

浙江大学学报（人文社会科学版） 2016年第5期46卷 71-82页

作者：查屏球复旦大学中国语言文学系上海200433

新近公布的《刘复墓志》的主体部分为刘复自撰,不仅完整介绍了刘复生平,而且述及他在天宝年间与王昌龄、李白交往之事,据此我们可以完整地认识刘复其人其诗。墓志中关于刘复早年生活的介绍不仅可让人了解到天宝学子的修业方式,而且还可... 详细信息

新近公布的《刘复墓志》的主体部分为刘复自撰,不仅完整介绍了刘复生平,而且述及他在天宝年间与王昌龄、李白交往之事,据此我们可以完整地认识刘复其人其诗。墓志中关于刘复早年生活的介绍不仅可让人了解到天宝学子的修业方式,而且还可对天宝年间以江宁为中心的江南诗坛有更真切的了解。这为解决天宝文学中几个悬案,如王昌龄被贬龙标时间、王昌龄在江宁主持雅集及授学之事,也提供了重要佐证,据此可对著名的《琉璃堂诗客图》做出新的解释。借助这方墓志,我们可对盛唐时期京城之外的诗学活动有更具体的认识。

关键词：《刘复墓志》天宝诗坛李白王昌龄《琉璃堂诗客图》

活动期溃疡性结肠炎患者凝血指标变化的meta分析

在线全文

学校读者我要写书评

暂无评论

细胞与分子免疫学杂志 2015年第11期31卷 1528-1532页

作者：查安生汪悦查瑞瑶安徽省中医院消化内科安徽合肥230038 安徽中医药大学安徽合肥230031 湖南中医药大学湖南长沙410208

目的评价活动期溃疡性结肠炎(UC)患者凝血指标变化。方法检索Pub Med、Medline、EMBASE、Web of science、Cochrane图书馆、中国学术期刊全文数据库(CNKI)、中国生物医学文献数据库(CBM)及万方数据等数据库公开发表的中英文文献,检索时... 详细信息

目的评价活动期溃疡性结肠炎(UC)患者凝血指标变化。方法检索Pub Med、Medline、EMBASE、Web of science、Cochrane图书馆、中国学术期刊全文数据库(CNKI)、中国生物医学文献数据库(CBM)及万方数据等数据库公开发表的中英文文献,检索时间均为从建库至2015年1月。对符合条件的研究进行提取资料和质量评价后,采用Stata12.0软件进行meta分析。结果共有28项病例-对照研究文献纳入meta分析,结果显示活动期UC患者血小板(PLT)、纤维蛋白原(FIB)、D-二聚体水平较正常组显著升高,平均血小板体积(MPV)、凝血酶原时间(PT)水平较正常健康组显著降低。敏感性分析显示,结果稳定性好,发表偏倚采用Egger及Begg法显示:关于D-二聚体的文献存在一定发表偏倚,其他指标的文献均无明显发表偏倚。结论活动期UC患者存在凝血指标的异常,可能存在高凝状态。

关键词：溃疡性结肠炎凝血 meta分析

Effect of secondary MO interaction on the regiospecificity in the reactions of α-ionones with singlet oxygen

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1993年第4期11卷 340-349页

作者： WU,guo-Sheng TAO,Tao HU,Jun zha,Zhen-Chuan WU,Bi-Qi Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032 Shanghai Institute of Organic Chemistry Chinese Academy of Sciences. Shanghai 200032

The eme reactions of α-ionones with singlet oxygen were examined to ascertain the effect of secondary Me interaction between the reactants on the reaction regiospecificity. Exclusive formation of 3-hydroxy-γ-ionones found in the reactions reveals favorable interaction of singlet oxygen with the acyclic α-hydrogen atom,On the other hand,no formation of 3-hy- droxy-β-ionones implies that the steric requirement was not met for the bond formation between zwitterionic perepoxide with C_1-hydrogen in the *** MMP21 and MNDO calculations indicate minus value of the secondary interaction energy for the aeyelie α-hydrogen abstrac- tion and a repulsion between the oxygen with C_1-hydrogen *** tilting of the double bond may account for favorable attack of singlet oxygen on C_*** explanation of the excellent regiospecificity was addressed and placed in proper mechanic prospective.

关键词： Effect of secondary MO interaction on the regiospecificity in the reactions of ionones with singlet oxygen

在线全文

学校读者我要写书评

暂无评论

职业教育可持续发展的基本原理

河北师范大学学报（教育科学版） 2013年第1期15卷 65-69页

作者：查吉德广州番禺职业技术学院高职教育研究所广东广州511483

差别原理、公平原理和效能原理是推动职业教育可持续发展的基本原理。要满足多样化的人才需求和教育需求,职业教育须遵循差别原理,不仅与普通教育差异化发展,而且应扩大内部的多样性。职业教育还应遵循公平原理,消解强制分流导致的教育... 详细信息

差别原理、公平原理和效能原理是推动职业教育可持续发展的基本原理。要满足多样化的人才需求和教育需求,职业教育须遵循差别原理,不仅与普通教育差异化发展,而且应扩大内部的多样性。职业教育还应遵循公平原理,消解强制分流导致的教育不公平问题,通过完善教育分流标准、建立现代职业教育体系,促进教育机会公平和发展机会公平,否则会失去合法性基础。效能原理将处于对立冲突状态的差别原理与公平原理统一起来,要求职业教育不仅考虑经济效能,还应考虑社会效能。提高职业教育效能,不仅应转变发展方式,提高人才培养质量,还应考虑经济发展水平,避免过度发展或超速发展。

关键词：职业教育差别原理公平原理效能原理

Content Determination of Astragaloside Ⅳ in Astragalus from Three Different Regions by HPLC

在线全文

学校读者我要写书评

暂无评论

Medicinal Plant 2018年第6期9卷 15-18,22页

作者： Wei XIN Jiangli NIE Ye HAN Yi PEI Nan YANg Yujie LANg Xi zha College of Horticulture and Landscape Architecture Tianjin Agricultural University

[Objectives] The content of astragaloside in Astragalus membranaceus(Fisch.) ***(Bge.) Hisao from three different regions was determined.[methods] Referring to the method recorded in the Chinese Pharmacopoeia(2015 edition),the content of astragaloside IV in *** was determined by HPLC.[Results] There were great differences in the astragaloside IV content of *** among different *** content of astragaloside IV in *** cultivated in Inner Mongolia was highest(0.155%),followed by that(0.143%) in *** cultivated in gansu,and the content of astragaloside IV in *** cultivated in Shanxi was lowest(0.080%).The contents of astragaloside IV in *** from different regions were all in line with the standard(not less than 0.040%) of Chinese Pharmacopoeia(2015 edition).[Conclusions]The content of astragaloside IV in *** cultivated in three different regions met the medicinal standards.

关键词： Astragalus membranaceus(Fisch.)Bge.var.mongholicus(Bge.)Hisao Astragaloside IV HPLC Content determination