基于信息融合理论的空间点目标识别实验结果分析

提出一种三级融合的多传感器信息融合空间点目标识别方法,将BP网络和D—S证据推理有效地结合起来.第一级融合采用神经网络进行识别,第二和第三级采用D—S证据理论进行识别.仿真结果证明,本文提出的方法能较好地解决复杂目标和诱饵的识别问题.     

传导电子与声子的相互作用对局域磁矩的影响

本文在Anderson提出的S—d混合模型中,考虑了传导电子与声子的相互作用(简写成EPI)和传导电子与d电子之间的库仑相互作用.主要讨论了EPI对局域磁矩的存在和大小的影响。     

齐次线性对数比模型的D—最优试验设计

讨论齐次线性对数比模型的D—最优设计问题。首先通过一个变换,将对数比换型变换为齐次线性模型,然后利用所得的模型求出设计的最优配置,最后证明相应的设计为D—最优设计。     

信息融合在空间点目标识别中的应用

提出一种三级融合的多传感器信息融合空间点目标识别方法,将BP网络和D—S证据推理有效地结合起来.第一级融合采用神经网络进行识别,第二和第三级采用D—S证据理论进行识别.经过三级融合后可以提高系统的识别率,尤其是在有噪声的情况下.仿真实验验证了算法的有效性.     

既约Goppa码的纠突发能力

[1][2]中讨论了既约Goppa码检测突发和随机错误的能力。本文完全从纠突发错误的角度,讨论既约Goppa码的纠突发能力。指出当n充分大时,存在有任意接近Sharma——Dass(S—D)限和Wyner——Ash(W—A)限的纠突发错误既约Goppa码。引理1 在q进制n重中,长度等于b相似文献   

关于城市固体废物卫生填埋场设计计算中的几个问题

本文讨论了城市固体废物填埋场设计中关于填埋坑渗出液生成量计算和渗出液在土层中的运动及污染物流向等问题。对正确理解质量平衡方程中S项的含义提出了更正意见,并讨论了Elzy—Lindstrom模型作为定性估计污染物流向的适用性。     

翼型失速特性的RANS方法与DES方法数值模拟对比分析

RAN S(R eyno lds-averaged N av ier-Stokes)加湍流模型是当前计算飞机粘性流场的最常用方法,数值实践说明要计算大分离流动,需要更高级的方法例如LES(Large Eddy S im u lation)或DN S(D irect N S S im u lation)。然而实际雷诺数下,LES和DN S对网格的要求太高,以至目前还难以应用。DES(D etached-Eddy S im u lation)方法结合了RAN S和LES的优点,通过对Spalart-A llm aras湍流模型中长度尺度的修正,在近壁面它体现为RAN S模型的特点,而在远离物面处又保持LES的亚格子模型的特性。论文对比了采用RAN S和DES方法数值模拟翼型失速特性的能力,并与实验结果进行了对比。结果表明,对大分离流动的数值模拟,DES方法体现出更强的能力。     

水化硅酸钙脱水相的水化特性

本文研究了水化硅酸钙C—S—H凝胶、C—S—H(Ⅱ)、C_2SH(A)、C_3SH_(1.5)的脱水相结构。并讨论了脱水相的结构与水化活性的关系。     

p_0—(强)半内积空间中算子理论的探讨

本文中,我们首次引入了P_0—(强)半内积空间,S—正常算子和S—亚正常算子的概念。通过对它们的讨论,我们得到了一系列重要而饶有兴趣的结果。     

3种套保效率评价模型的比较研究

套保效率评价模型能否准确反映套保行为的价值直接影响着套保决策的制定和质量，一旦效率评价出现偏差，将导致投资者做出错误判断，甚至套保行为的失败。本文以沪铜为例，分析了目前普遍采用的3种套保效率评价模型——风险减少程度、夏普比率和Lindal’mean—Lindal’S．D在实际应用中存在的偏差，并提出改进套保效率评价模型的相关建议。     

力觉临场感遥操作机器人(3):环境的动力学描述

力觉临场感遥操作机器人系统是一个典型的人-机-环交互系统.环境是遥操作机器人系统最终的环节,也是操作者感知和作用的对象,环境的动力学特性对整个遥操作机器人系统的控制性能会产生直接的影响.通过分析环境在力觉临场感遥操作机器人系统中的动力学特性,建立了环境在碰撞接触、线性平稳接触和非线性平稳接触3类情况下的动力学模型,并给出了模型的等效阻抗形式,为力觉临场感遥操作机器人系统的分析提供了基础.     

Effect of the drive system on locomotive dynamic characteristics using different dynamics models

Based on the theory of vehicle-track coupled dynamics and gear system dynamics, a locomotive-track coupled spatial dynamics model is established by considering the dynamic effects of the gear transmission system. The vibration responses of a locomotive's major components are then simulated using three locomotive-track models, namely the proposed dynamics model with the gear transmissions, a locomotive-track coupled dynamics model that considers the traction motor, and the classical Zhai's model. The locomotive dynamic responses of the three models are extracted and compared to reveal discrepancies between them so as to explore the dynamic effects of the power transmission system and clarify potential applications of these models. The results indicate that the dynamic effects of the gear transmissions have a negligible influence on the lateral vibrations of the locomotive components. However, they have obvious effects on the vertical and longitudinal vibrations of the wheelset and the traction motor. Another advantage of the locomotive dynamics model that considers the dynamic effects of the gear transmissions is that the dynamic performance of the drive system can be assessed in the vehicle vibration environment. This study provides theoretical references that can assist researchers in choosing the most appropriate locomotive dynamics model according to their specific research purpose.     

基于系统动力学的供应链网络仿真模型的研究

分析了供应链网络结构,用传统的线性系统的理论和方法难以描述供应链这样一个非线性的动态复杂系统的问题．根据供应链系统与系统动力学的特点,论述了基于制造业企业供应链系统所涉及的关键因素,探讨了如何建立供应链网络系统动力学模型．通过因果关系分析,构建了基于系统动力学的供应链网络仿真模型．     

Composite modeling method in dynamics of planar mechanical system

This paper presents a composite modeling method of the forward dynamics in general planar mechanical system. In the modeling process, the system dynamic model is generated by assembling the model units which are kinematical determinate in planar mechanisms rather than the body/joint units in multi-body system. A state space formulation is employed to model both the unit and system models. The validation and feasibility of the method are illustrated by a case study of a four-bar mechanism. The advantage of this method is that the models are easier to reuse and the system is easier to reconfigure. The formulation reveals the relationship between the topology and dynamics of the planar mechanism to some extent. Supported by the National Natural Science Foundation of China (Grant No. 50605042) and the National Basic Research Program of China (973 Program) (Grant No. 2006CB705400)     

基于系统动力学的城市抗震防灾能力评估

为解决城市抗震防灾系统由于本身非线性、复杂性、动态发展性、自组织性等特点致使其难以量化评估的问题,实现依据地震时序的城市抗震防灾能力的动态评估,提出了基于系统动力学的城市抗震防灾能力动态评估模型.首先,回顾总结了城市抗震防灾相关研究的进展,总结了以往城市抗震防灾相关研究的不足;其次,给出了基于系统动力学城市抗震防灾能力评估研究的基本理论及框架;最后,运用系统动力学构建了震前重点片区的人员紧急疏散、震后薄弱区短期疏散及震后人员伤亡和救援3个模型,通过模型模拟为城市抗震防灾规划的具体实施提供了一定参考依据,且证实了系统动力在城市抗震防灾方面的实用性.     

Hamiltonian realization of power system dynamic models and its applications

Power system is a typical energy system. Because Hamiltonian approaches are closely related to the energy of the physical system, they have been widely researched in recent years. The realization of the Hamiltonian structure of the nonlinear dynamic system is the basis for the application of the Hamiltonian methods. However, there have been no systematically investigations on the Hamiltonian realization for different power system dynamic models so far. This paper researches the Hamiltonian realization in power systems dynamics. Starting from the widely used power system dynamic models, the paper reveals the intrinsic Hamiltonian structure of the nonlinear power system dynamics and also proposes approaches to formulate the power system Hamiltonian structure. Furthermore, this paper shows the application of the Hamiltonian structure of the power system dynamics to design non-smooth controller considering the nonlinear ceiling effects from the real physical limits. The general procedure to design controllers via the Hamiltonian structure is also summarized in the paper. The controller design based on the Hamiltonian structure is a completely nonlinear method and there is no linearization during the controller design process. Thus, the nonlinear characteristics of the dynamic system are completely kept and fully utilized. Supported in part by the National Natural Science Foundation of China (Grant Nos. 50707009 and 50525721), in part by Program for Changjiang Scholars and Innovative Research Team in University under IRT0515 and in part by Ministry of Education of China (Grant No. 20070079014)     

应用结构分析法对农用拖拉机需求发展的研究

根据系统动力学原理,分析农用拖拉机需求系统的内部结构,找出结构的因果关系,建立需求系统的反馈环结构。在此基础上,应用数学中的差分方程形式,建立数学逻辑的模拟模型。然后,用专用的电子计算机模拟语言DYNAMO编制程序,进行模拟运算。根据选用的不同参数,得出不同的模拟结果,为决策者提供多种可能的未来需求动态,经过分析,做出决策选择。     

基于神经网络的平面五杆可调机构的动力学解析模型

应用Kane动力学方法对平面可调五杆机构进行了动力学分析,建立了平面五杆机构的动力学解析模型。并研究了构件几何参数和物理特性对广义驱动力矩的影响规律。在此基础上,应用BP神经网络对可调五杆机构逆动力学模型进行了辨识,将整个动力学模型系统分为3个子系统,分别采用BP神经网络系统对广义质量矩阵、向心力哥氏力矩阵和重力矩阵进行学习,求解得到可调平面五杆机构的逆动力学模型问题。     

考虑限位器的汽车非线性系统振动特性

建立了考虑限位器的悬架非线性隔振系统的数学模型.对引进弹性限位器且不考虑限位器接触问题的弹簧阻尼系统悬架进行了力学分析,利用系统动力学和随机振动理论,将汽车简化为1/2的四自由度模型,建立了考虑悬架隔振系统非线性特性的整车系统在路面随机激励下的非线性动力学方程,最后用Monto Carlo法模拟路面随机激励谱,在时域内对整车非线性系统振动特性进行仿真,并与传统的考虑线性悬架系统的整车动力学特性进行对比,以研究悬架隔振系统非线性特性对汽车平顺性的影响.     

一类不确定遥操作系统的混杂控制

提出了一种基于自适应逆动力学和位置误差(PEB)结构的混杂控制方法,以克服动力学参数不确定性对遥操作系统透明性的影响。首先将操作者和环境模型分别融入到主、从机器人的动力学模型中;然后基于逆动力学设计自适应控制器,将其融入PEB结构,并利用李亚普诺夫函数法对系统性能进行了分析。仿真研究表明,该控制方案具有良好的位置和力跟踪性能。