THE SELF-STABLE REGION APPROACH FOR SECOND ORDER SYSTEMS

1.IntroductionThecolltrolproblemofnonlinearuncertainsystemshasbeenextensivelyresearchedformanyyears.Manymethodshavebeenproposedandsomeprogresshasbeenmade.[1]poiedsoutthatsomesecondordersystemshaveaninherelltpropertythatthereexistscertainregioninwhichalltrajectoriesofthesystemremaininginitaftercertaintimeTwillconvergetotheorigin.Basedonthisproperty,anewapproachhajsbeenputforwardtoconstructacolltinuousfeedbacklawsuchthatallsystem'strajectoriesmovetowardtheregionandeventuallyremaininit.In[2,3],a…     

An Adaptive Identification and Control Scheme Using Radial Basis Function Networks

1.INTaODUCTIONThemultilayerfeedforwardneuralnetworks(MFNN)hasbeenwidelyappliedinmanyfieldssuchaspatternrecognition,nonlinearoptimization,systemidentificationandcontrol.Thesimpleback-propagation(BP)learningalgorithmisusuallyadoptedtoupdateitsweights.TheBPalgorithm,however,suffersdrawbacksofslowconvergenceandunpredictablesolutionsduringlearning.Althoughmailyapproachessuchasvariablestepsize,conjugategradient,pseudo-Newtonmethods[4]andothermethods[3,10],havebeendevelopedtoovercometheproble…     

生态学实验教学模式改革的探讨

本文结合生态学实验教学模式改革的进行,探讨生态学实验教学过程初步探索和实践的效果,并且分析生态学实验教学改革中的不足,对高校开展生态学教学改革研究具有重要意义。     

宇宙年龄和宇宙物质密度

根据爱因斯坦广义相对论,时空弯曲,宇宙是有限的。现在已被主流物理学家普遍接受的是标准宇宙论,按标准宇宙论经过严格的数学推导,演算得到了宇宙的年龄、宇宙物质密度。作者根据广大天体物理工作者认可的观察数据和结论,通过初等数学的计算,得到的结果大相径庭。根本没天体物工作者寻找的暗物质。     

Mach׳s principle as action-at-a-distance in GR: The causality question

A part of the revival of interest in Mach׳s principle since the early 1960s has involved work by physicists aimed at calculating various sorts of frame-dragging effects by matter shells surrounding an interior region, and arguing that under certain conditions or in certain limits (ideally, ones that can be viewed as plausibly similar to conditions in our cosmos) the frame dragging becomes “complete” (e.g. Lynden-Bell, Katz, & Bičák, 1995) . Such results can bolster the argument for the satisfaction of Mach׳s principle by certain classes of models of GR. Interestingly, the frame-dragging “effect” of (say) a rotational movement of cosmic matter around a central point is argued by these physicists to be instantaneous—not an effect propagating at the speed of light. Not all physicists regard this as unproblematic. But rather than exploring whether there is something unphysical about such instantaneous “action at a distance”, or a violation of the precepts of Special Relativity, I am interested in exploring whether these physicists׳ calculations should be thought of as showing local inertia (resistance to acceleration) to be an effect, with distant matter distributions being the cause. I will try to apply some leading philosophical accounts of causation to the physical models of frame dragging, to see whether they imply that the frame dragging is superluminal causation. I will then offer reflections on the difficulties of applying causal talk in physical theories.     

本科生分子生物学实验教改中存在的问题及对策

作者结合自己分子生物学实验教学经验,介绍了教研室本科生分子生物学实验教学改革现状,肯定了实验教学改革效果,同时对改革中存在的问题进行深入分析,并提出相应对策。     

克里普克论知识悖论

知识悖论及其解决涉及到知识论的核心问题。克里普克在一篇新作中对意外考试悖论进行了深刻分析,并指出这一悖论的产生是由于错误地使用了"知识的持久性"这一前提,并以此为基础提出了一种新的知识悖论,即独断论悖论。通过分析可见,克里普克对"知识的持久性"的反驳以经典的知识论为框架,面对经典知识论所遭受的强有力的挑战,克里普克对意外考试悖论的解决缺乏可靠的理论支撑。知识悖论触及的是知识论的核心问题,任何尝试性的解决方案都要重新思考知识的本质到底是什么。     

基于网络环境下自主学习问题的解决对策研究

本文在自主学习的详细分解研究基础上，通过对网络环境下的自主学习方式的解析，阐述了自主学习的内涵和特征，总结了网络环境下中学生自主学习过程中存在的问题，并给出了相应的解决建议，进而提高我国大学生自主学习的能力。     

农业技术进步的计量经济模型

本文根据[1]提出的基本原理,在[2]的基础上,通过矫正自然灾害和耕地面积的影响,并在考虑农业基建投资动态折旧的前提下,给出了农业技术进步的计量经济模型。最后通过实例分析加以说明。     

满足互补原理的半单复合模型

本文系统分析了SU(N)×SO(M)半单超色群的手征三前子模型.我们发现:SU(3)×SO(5)模型满足互补原理要求;由′tHooft方程及Bars条件可以给出三代夸克、轻子谱;超色群G_(MC)和规范色味子群G_(CF)都是渐近自由的,因此可以构造出具有低的超色禁闭标度A_(MC)的现实模型.我们还发现,本模型中存在二个超色标度.在这两个标度之间,模型类似于费米——玻色模型,这可以简化前子的动力学.