动态结构系统可靠性的频率灵敏度分析

基于频率可靠性理论提出了动态结构系统的频率可靠性灵敏度的计算方法.根据动态结构系统的固有频率与激振频率差的绝对值不超过规定值的关系准则,定义了随机结构振动问题的可靠性模式和系统的可靠度,进而提出了频率可靠性灵敏度分析方法,应用随机摄动技术、可靠性理论和灵敏度方法,推导出参数为正态随机变量时的准失效概率灵敏度的表达公式,对动态结构系统共振问题的可靠性灵敏度分析方法进行了探索.并在此基础上,以一简化的车身-车轮-路面关系的系统模型为例,由可靠性灵敏度矩阵可以看出,各随机参数的变化对动态结构系统的可靠性及失效性的影响程度也不同,其计算结果与通常的定性分析结果完全一致,验证了所提方法的有效性.该方法为动态结构系统的优化和设计提供了依据.

动态系统结构与分形公司

传统的静态企业结构不能适应快速变化的环境，企业需要可以快速重构的动态结构，以内部变化来适应外部变化。系统的构成单元应该具有决策智能、自组织、协商合作和自治能力。本文研究了企业动态结构的需求与特点，同时介绍了分形公司的动态结构思想。

一类变结构动态系统的非光滑最优性条件

研究了一类事件驱动的变结构动态系统的非光滑最优性条件.通过引入一个新的时间变量,将变结构动态系统的最优性问题转化为古典动态系统的最优性问题.基于广义微分和古典动态系统的最优性理论,得到了该系统的Frechet上微分形式的必要性条件,推广了已有文献的相关结论.结果表明,在系统的连续运行过程中,控制变量、协态变量和状态变量满足最小值原理和协态方程.在系统的运行模型发生改变时,协态变量产生一定的跳跃,哈密尔顿函数连续.最后通过一个算例说明了该结论的有效性.

需要的动态系统结构理论与全民健身

人的需要是复杂多样的,构成了多层次的动态系统结构体。需要系统的结构决定需要系统的功能,需要的动态系统结构理论与全民健身有着密不可分的关系。全民健身的法制化为人们的健身需要提供了良好的社会大环境;需要的动态系统结构理论强化人们的思想认识,对全民健身具有指导作用;全民健身不但能满足人们的维生和享受需要,而且能满足人们的表现需要和发展需要。

《围护结构动态负荷传递函数模型合成的系统辨识法》的补充说明

分析了《对上海交大〈围护结构动态负荷传递函数模型合成的系统辨识法〉读后感》所作评论的正确性 ,指出该文作者并未完全理解原文的研究目的、研究内容和写作方式 ,而且一些观点也有错误。

生物信息材料学初探

生物信息材料学是融合医学、信息学、材料学等多个学科的一门交叉学科,内容涵盖建立动态平衡的结构系统模型、生命结构系统的演化和生物信息材料的研制及其利用3个部分。首先,通过数学推理的方法论述了符合“阴阳五行模型”结构系统所具有的动态平衡的特性;其次,论证了生命结构系统是从具体结构主导的演化发展到抽象结构主导的演化过程中诞生,进而阐述了疾病与健康的统一理论,提出“以邪扶正”和“以正扶正”两种治疗疾病、维护健康的方法;最后,提出让生物通过识别设计加工而成的材料中的结构信息,通过调节基因表达的创新材料设计目标的理论和方法,建立生物信息材料学。基于此,运用生物信息材料学中维护生命健康的理论和方法所研制出的功能性材料,可应用于治疗疾病的药物、预防保健的功能食品,并拓展应用到有益生命健康的化妆品、日用品等领域。

增强党组织政治功能和组织功能:发展脉络与理论启示

中国共产党作为一个组织系统与有机统一体,党组织的政治功能和组织功能具有相辅相成性,二者并非并列关系与对等关系,而是“是什么”与“怎么干”之理论与实践关系,党组织的组织功能是政治功能的“物质支撑”与行动落实。纵观中国共产党在各个历史时期增强党组织政治功能和组织功能的历史发展脉络,可以得出三点基本经验:即党的领导、党的历史使命、党的政治功能与组织功能相辅相成,党的政治功能、组织功能必须围绕党的领导与党的政治路线来进行;党的组织体系、政治功能、组织功能相辅相成,政党功能必须以政党组织体系为载体、以加强党的组织建设为保障;党的政治功能和组织功能具有整体性,但各级党组织的政治功能和组织功能又具有一定的层级差异性与时代差异性。深刻认识与总结增强党组织政治功能和组织功能的历史逻辑与基本经验,需要根据政党组织系统-结构-功能的动态平衡进行深入分析。

风险投资控制管理运营机制性激励缺失研究

我国风险投资的法律环境和政策要素,与风险投资运营宏观要求预期出现相悖性约束情景,致使风险投资事业举步不前,蛰伏不振。唯有完善、健全风险投资机制动态系统结构模型所要求的机制性激励体系,以推进国家高新技术产业化,完成国民经济产业结构现代化调整的战略目标。

Changes of Mobile Internet Ecosystem Structure and Suggestions for Regulatory Policy

The mobile Intemet industry has exp- erienced dramatic changes as plenty of new applications and business models emerged. This study conducts a qualitative review on the changes through adopting business ecosystem approaches. An analytical framework is estab- lished for reviewing the structure of mobile Internet business ecosystem. Then the core value, key actors, and inter-firm relationships of the mobile Internet ecosystem in the past and in the present are compared. It is found that the ecosystem structure has shifted from an MNO-centric model to a polycentric one with highly expanded value sources and di- versified keystone players. Accordingly some suggestions for regulatory policy makers are provided in terms of the roles of mobile Inter- net in social welfare improvement, the call for a convergent regulatory system, and chal- lenges for information security regulation.

Dynamic Behavior of a Predator-prey System with Stage-structure for Prey

In this paper, we considered the predator-prey system with stage-structure for prey, where the predators predate immature preys only. The positivity and boundedness of the solutions and asymptotic stability of equilibrium were firstly discussed, and then uniformly persistent sufficient conditions of populations were found.

Consensus tracking protocol and formation control of multi-agent systems with switching topology

Consensus tracking control problems for single-integrator dynamics of multi-agent systems with switching topology are investigated. In order to design effective consensus tracking protocols for a more general class of networks, which are aimed at ensuring that the concerned states of agents converge to a constant or time-varying reference state, new consensus tracking protocols with a constant and time-varying reference state are proposed, respectively. Particularly, by contrast with spanning tree, an improved condition of switching interaction topology is presented. And then, convergence analysis of two consensus tracking protocols is provided by Lyapunov stability theory. Moreover, consensus tracking protocol with a time-varying reference state is extended to achieve the fbrmation control. By introducing formation structure set, each agent can gain its individual desired trajectory. Finally, several simulations are worked out to illustrate the effectiveness of theoretical results. The test results show that the states of agents can converge to a desired constant or time-varying reference state. In addition, by selecting appropriate structure set, agents can maintain the expected formation under random switching interaction topologies.

Dynamic Friction Control Using Dynamic Structured RFNN and Friction Parameter Estimator

A nonlinear dynamic friction control is dealt with using dynamic friction observer and intelligent cantrol. The adaptive dynamic friction obsrver based on the LuGre friction is proposed to estimate the friction parameters and a directly friction state variable The dynamic structured Fuzzy Neural Network （RFNN） is designed to give additional robustness to the cantrol system under the presence of the friction model uncertainty. A proposed composite cantrol scheme is applied to the position tracking control of the servo systen. The performances of the proposed friction observer and the friction controller are demonstrated by simulation.

基于特殊历史数据段挖掘的切换Hammerstein模型辨识

本文提出了一种基于特殊历史数据段挖掘的切换Hammerstein模型辨识方法。特殊数据段是指处于稳定状态和稳定斜坡响应的数据段。首先,根据稳态数据采用随机抽样一致算法辨识静态非线性子系统。其次,根据稳定的斜坡响应数据利用密度峰值聚类算法辨识切换Hammerstein模型线性动态子系统的结构和相应的操作区间。最后,根据操作区间划分历史数据集,采用最小二乘算法辨识切换的多个线性动态子系统的模型参数。数值仿真和实验案例结果表明,与标准Hammerstein辨识方法相比,所提方法可以实现不同工作点切换的多个线性动态子模型的结构辨识及操作区间划分,降低了模型结构未知时切换动态子系统对模型参数辨识的影响,提高了切换Hammerstein模型的辨识精度。

CCPA: Component-based communication protocol architecture for embedded systems

For increased and various communication requirements of modem applications on embedded systems, general purpose protocol stacks and protocol models are not efficient because they are fixed to execute in the static mode. We present the Component-Based Communication Protocol Architecture （CCPA） to make communication dynamic and configurable. It can develop, test and store the customized components for flexible reuse. The protocols are implemented by component assembly and support by configurable environments. This leads to smaller memory, more flexibility, more reconfiguration ability, better concurrency, and multiple data channel support.

Experimental and Simulation-based Investigation of a Velocity Controller Extension on a Ball Screw System

The background of this contribution is the enhancement of the achievable accuracy of servo-screw-presses. Therefore, the paper is concerned with the improvement of the dynamic precision for direct driven servo axes which is still restricted by structural vibrations. For this purpose, a ball screw test rig was analyzed for which the standard cascade control structure was extended by an additional velocity feedback. This structural extension has the potential to improve the controller performance significantly due to a better damping of low frequent vibrations. Furthermore, a parametric dynamic model for the control structure was derived to investigate the effects of the controller extension. For this analysis, the influences of the used tuning factors and filters is discussed in the frequency domain based on bode plots. The results of these cognitions are transferred to the time domain and illustrated by step responses. In addition, an evaluation by the criterion of the IAE （integral of absolute error） and the Prony analysis is carried out. Finally, the results are experimentally verified at the ball screw test rig. The paper closes with the conclusions.

Influence of Random Track Irregularities on Dynamic Response of Bridge/Track Structure/High-Speed Train Systems

Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process. The study presents the results of numerical dynamic analysis of advanced virtual models of composite BTT （bridge/ballasted track structure/high-speed train） systems. The analysis has been conducted for a series of types of single-span simply-supported railway composite （steel-concrete） bridges, with a symmetric platform, located on lines with ballasted track structure adapted for high-speed trains. The bridges are designed according to Polish bridge standards. A new methodology of numerical modeling and simulation of dynamic processes in BTT systems has been applied. The methodology takes into consideration viscoelastic suspensions of rail-vehicles, nonlinear Hertz wheel-rail contact stiffness and one-side wheel-rail contact, physically nonlinear elastic-damping properties of the track structure, random vertical track irregularities, approach slabs and other features. Computer algorithms of FE （finite element） modeling and simulation were programmed in Delphi. Both static and dynamic numerical investigations of the bridges forming the series of types have been carried out. It has been proved that in the case of common structural solutions of bridges and ballasted track structures, it is necessary to put certain limitations on operating speeds, macadam ballast and vertical track roughness.

Use of Crescent Shaped Braces for Controlled Seismic Design of Ductile Structures

It is known that the seismic response of a structural system is highly influenced, in addition to the earthquake input, by the dynamic characteristics of the system itself. This paper presents an approach for the identification of the characteristics of the structural system resisting to horizontal loads which enables to satisfy given seismic performance objectives. This is achieved by considering a total conceptual separation between the structural systems resisting to vertical and horizontal loads. The proposed approach is first briefly developed in general within a Performance-Based Seismic Design （PBSD） framework and then fully applied to the case study of a five-storey steel building structure. It is composed of three basic steps： （1） identification of the fundamental characteristics which should be possessed by the horizontal resisting system to satisfy a multiplicity of performance objectives, （2） development of a peculiar horizontal resisting system composed of ＂crescent shaped braces＂ which are specifically calibrated to satisfy given performance objectives, （3） verification, by means of appropriate time-history analyses, of the seismic performances achieved. In detail, the horizontal resisting system is calibrated to satisfy a multiplicity of performance objectives through the identification of an ＂objectives curve＂, in the Force-Displacement diagram, of the mechanical characteristics of the structure. The calibration is obtained by methods/tools borrowed either from Direct Displacement-Based Design （DDBD） or Force-Based Design （FBD）, depending on the specific performance objective to be imposed. The applicative example has been carried out with reference to three performance objectives and has led to the identification of a horizontal resisting system composed of special bracing elements capable of realizing a sort of properly-calibrated seismic isolation called crescent-shaped braces. The results obtained through non-linear dynamic analyses have shown that the proposed approach leads to the congruity between the imposed and the achieved seismic performances.

Spatiotemporal variability of ocean chemistry in the early Cambrian,South China

Following the Ediacaran metazoan radiation,the "Cambrian Explosion" set up the major framework of todays' animal phyla as well as modern marine ecosystem.Here,we present a preliminary investigation on the temporal and spatial(from shallow to deep waters) variations of the early Cambrian ocean chemistry in South China through analyzing a Fe-S-C systematic dataset integrated from literature.Our investigation indicates that the early Cambrian deep ocean in South China was still anoxic and Fe2+-enriched(i.e.,ferruginous) although its surface was oxic,and in between a metastable euxinic(anoxic and sulfidic) water zone may have dynamically developed in anoxic shelf waters with an increasing weathering sulfate supply.Furthermore,accompanying marine transgression and regression cycles in the early Cambrian,such a "sandwich" structure in ocean redox chemistry demonstrates five evolutional stages,which can be well correlated to the spatiotemporal patterns of fossil records in South China.The good correlation between metazoan fossil occurrences and water chemistry in South China suggests that early animals possibly possessed ability to inhabit anoxic but generally not euxinic environments as free H2S was fatal to most eukaryotes.This view can well explain why those small shell fauna and sponges disappeared from shelf to slope areas where sulfidic Ni-Mo-rich shales were widely deposited.Thus,we conclude that the spatiotemporal variations of ocean chemistry and its biological effects probably played a key role in the phased animal radiations and "extinctions" in the early Cambrian.

Evolutionary algorithm based on dynamical structure of membrane systems in uncertain environments

In this paper, a new evolutionary algorithm based on a membrane system is proposed to solve the dynamic or uncertain optimization problems. The proposed algorithm employs objects, a dynamical membrane structure and several reaction rules of the membrane systems. The object represents a candidate solution of the optimization problems. The dynamical structure consists of the nested membranes where a skin membrane contains several membranes, which is useful for the proposed algorithm that finds optimal solutions. The reaction rules are designed to locate and track the optimal solutions of the dynamic optimization problems （DOPs）, which are inspired by processing the chemical compounds in the region of cellular membranes. Experimental study is conducted based on the moving peaks benchmark to evaluate the performance of the proposed algorithm in comparison with three state-of-the-art dynamic optimization algorithms. The results indicate the proposed algorithm is effective to solve the DOPs.

ROLE OF HARVESTING IN CONTROLLING CHAOTIC DYNAMICS IN THE PREDATOR-PREY MODEL WITH DISEASE IN THE PREDATOR

Predator prey model with harvesting is well studied. The role of disease in such system has a great importance and cannot be ignored. In this study we have considered a predator prey model with disease circulating in the predator population only and we have also considered harvesting in the prey and in the susceptible predator. We have studied the local stability, Hopf bifurcation of the model system around the equilibria. We have derived the ecological and the disease basic reproduction numbers and we have observed its importance in the community structure of the model system and in controlling disease propagation in the predator population. We have paid attention to chaotic dynamics for increasing the force of infection in the predator. Chaotic population dynamics can exhibit irregular fluctuations and violent oscillations with extremely small or large population abundances. In this study main objective is to show the role of harvesting in controlling chaotic dynamics. It is observed that reasonable harvesting on the prey and the susceptible predator prevents chaotic dynamics.