共查询到20条相似文献,搜索用时 93 毫秒
1.
文献[6]已经证明了 Julia 例外函数集 J,在一致球面收敛的意义下是一个线性闭色。本文在 Julia 例外函数集 J 上引入了距离函数,讨论了距离空间[J,ρ]的一些拓扑性质,得到了正规族理论中,一致有界的连续函数集正规和解析函数集正规这两个定理的抽象形式。 相似文献
2.
随着工业发展对大容量高压变频装置的需求,传统的两电平结构已无法满足应用要求,对三电平空间矢量脉宽调制(Space Vector Pulse Width Modulation,SVPWM)的算法进行研究,无论在技术上还是在实际应用中都有十分重要的意义。首先介绍了三电平变换器的拓扑结构以及空间电压矢量控制技术的基本原理,然后详细分析了三电平SVPWM算法,并对每个主要步骤都提出了matlab仿真模块,最后,搭建了一个三电平逆变器仿真模型,通过matlab环境下的仿真分析,证实了理论分析的正确性和所提算法的有效性。 相似文献
3.
4.
5.
6.
为改善液压启闭机机架结构的位移情况,文章设计一种基于ANSYS的液压启闭机机架结构拓扑优化方法。首先建立几何模型与有限元分析模型,然后对液压启闭机机架结构预应力状态模态分析,最后设定优化目标函数,完成液压启闭机机架结构拓扑优化。实验证明,此次研究的优化方法不仅改善了结构的位移情况,还降低了最大应力与结构自重。 相似文献
8.
9.
随着齿轮箱结构的不断变化,齿轮箱结构在工作过程中出现了较强的振动,说明传统静力学设计手段已经无法满足齿轮箱的结构设计需求。根据以往工作经验,总结大型船用齿轮箱系统结构特点和基本参数及振动响应,从箱体噪声控制方案分析、箱体优化的具体方法、拓扑优化、SIMP法的数学模型、动态响应约束下的结构拓扑优化模型方面,论述动态性能分析下的结构优化策略。 相似文献
10.
本文介绍了一种基于GIS平台的营配信息平台系统,该系统通过在建立企业统一的电网设备及客户信息模型、基础资料和拓扑关系的基础上,拓展客户综合停电管理、面向客户的供电可靠性管理、线损四分管理、业扩报装辅助决策及配网建设规划等高级应用,打通从电网设备到客户基础资料的拓扑关系,从而消除现有生产MIS、营销MIS、配电GIS等系统的数据孤岛,最终实现营配合一.本文详细介绍了该系统的整体构架、系统功能和特点. 相似文献
11.
12.
13.
We examine the potential for expansion of the white space spectrum sharing model in the 400 MHz band. As opposed to UHF broadcast spectrum, which contains unassigned or idle segments known as white spaces, the 400 MHz band is characterised by intensive licence usage. However, productive spectrum usage does not guarantee allocative efficiency, which would require knowledge of the highest value service for each licence. 400 MHz frequencies are not priced on opportunity cost. It is therefore difficult to ascertain the economically efficient mix of services to deploy in the 400 MHz band. Drawing parallels with the high-economic value revealed and generated through the operations of unlicensed white space devices in UHF broadcast spectrum, we identify untapped 400 MHz spectrum capacity, which we refer to as narrowband spaces. Encouraging dynamic spectrum usage of narrowband spaces could, similarly to TV white space usage help realise the efficient allocation of the 400 MHz band. However, the narrowband nature of the 400 MHz licences and high licensing turnover imply a significantly different concept of dynamic spectrum access than that considered for TV Bands. The paper discusses regulatory implications and the type of services suited to exploit narrowband spaces. 相似文献
14.
In this work we propose an efficient dynamic programming approach for computing replenishment cycle policy parameters under non-stationary stochastic demand and service level constraints. The replenishment cycle policy is a popular inventory control policy typically employed for dampening planning instability. The approach proposed in this work achieves a significant computational efficiency and it can solve any relevant size instance in trivial time. Our method exploits the well known concept of state space relaxation. A filtering procedure and an augmenting procedure for the state space graph are proposed. Starting from a relaxed state space graph our method tries to remove provably suboptimal arcs and states (filtering) and then it tries to efficiently build up (augmenting) a reduced state space graph representing the original problem. Our experimental results show that the filtering procedure and the augmenting procedure often generate a small filtered state space graph, which can be easily processed using dynamic programming in order to produce a solution for the original problem. 相似文献
15.
万希 《地质技术经济管理》2008,(2):81-83
我国正在大力提倡创新型国家的建设,而落实到最为根本上来讲就是培养创新型人才的问题,对于组织来讲就是找到具有创新潜质的人才,而企业要获取创新型人才,就必须关注创新型人才的培养,在创造的方法上可以考虑使用创意空间的办法。 相似文献
16.
航天产业与市场运行机制的兼容性分析 总被引:2,自引:0,他引:2
本文从航天技术商业化和航天活动主体多元化趋势的角度来分析航天产业与市场运行机制兼容的基础,分析了航天产业市场竞争的特点,制约我国航天产业引入市场运行机制的几个因素,并提出了我国航天产业建立和完善市场运行机制的对策建议。 相似文献
17.
图像的自相关函数是表征空间域图像像素之间相关性的重要特性之一。在彩色图像所涉及的多种不同颜色空间下,颜色分量图像的自相关特性有所差异。为了获取彩色图像颜色空间与各分量图像自相关之间的关系,征RGB、KCH、LAB、OHTA和YCC5种颜色空间下,利用Matlab软件,对不同色彩特征的多幅彩色图像进行了分量自相关分析。结果表明:采用不同颜色空间的分量图像自相关水平各异;采用对立色空间(LAB/OHTA/YCC)分量图像的平均自相关水平高于采用RGB和LCH的分量图像;在对立色空间中,彩度分量的自相关水平明显高于其明度、亮度分量,由此使彩色图像的可压缩率得以提升。 相似文献
18.
19.
We estimate nonmarket values for natural views in an urban setting. These views contain the aesthetics of natural areas commonly found in public parks and open space, and offer an aspect of property valuation that previous research is unable to disentangle from proximity to parks and open space. We incorporate machine learning techniques on Google Street View images to identify natural views in an urban setting. We find positive capitalization rates associated with household views of park-like properties. Estimates are robust to a variety of specifications, including models that are identified off of new developments on neighboring properties and falsification tests that help to rule out the effect of a broader neighborhood environment. From a policy perspective, our results inform as to the optimal size, location, and shape of open space. Furthermore, machine learning methods used in the construction of our view variable provide a potentially powerful tool for other nonmarket valuation studies. 相似文献
20.
应用响应面结合空间映射方法.在第一次迭代拟合极限状态函数,其它迭代应用映射技术在第一迭代响应面基础上映射调整得新得极限状态函数,并进行可靠性分析。方法改变了序列响应面方法评价可靠性时需要反复对模型进行试验设计、分析并拟合极限状态函数得执行过程.从而大大降低了模型分析的计算量。 相似文献