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关于几种变步长LMS算法的讨论 总被引:1,自引:0,他引:1
LMS算法是自适应滤波应用中一个非常重要的算法,在传统的LMS算法基础上又有多种改进的算法被提出,以适应实际的需要.文章通过举例的方式,列举几种常见的改进型LMS算法,并说明其改进后的优点以及在实际应用中存在的缺陷. 相似文献
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介绍了自适应噪声抵消系统及其核心部分一自适应滤波器的基本原理和常见算法,并采用LMS、NLMS算法在Matlab平台中进行了系统消噪性能的仿真对比,讨论了不同参数设定对系统性能的影响.结果表明,当其他条件不变时,所选用步长或者滤波器阶数的增加,会造成滤波器自适应学习时间加长,失调系数变大,消噪性能趋于恶化;对于有色噪声的消除,NLMS算法有明显优势和效果,而LMS算法则存在梯度噪声被放大、失真度高等问题. 相似文献
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针对检测舰船磁场信号时信噪比较低的问题,提出了一种基于变步长LMS算法的检测方法.根据舰船磁场信号的实际特征,首先采用小波阈值去噪法对实测信号进行处理,去除测量信号中的白噪声,并提取最后一层的低频分量,滤除高频噪声;再采用变步长LMS算法对低频分量进行自适应滤波,进一步滤除噪声,提取舰船磁场特征信号.船模实验的结果表明,该算法可以显著提高信噪比,增强了对舰船磁场信号的检测能力. 相似文献
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在传统的LMS(Least Mean Square)算法中,固定步长选取影响收敛速度与稳态误差,而且两者不可兼得.为此,本文提出了一种改进的LMS算法.在计算机仿真自适应信道均衡中,该算法的性能明显优于传统的LMS算法,而计算量增加甚少.理论分析与计算机模拟证实了该算法的优越性. 相似文献
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远距离海上雷达探测由于海上环境的复杂性容易受到杂波干扰,常用的最小均方算法通过在干扰噪声中形成主波束并引导至目标信号,有效解决了杂波干扰问题。通过对自适应智能天线波束形成技术的海上应用进行研究,给出了常用的天线阵列结构模型和信号模型,研究了智能天线中的自适应波束成型算法,目前在这一领域的解决方案中最小均方算法最为常见,但其存在收敛速度差、通用性低等问题。本文将优化遗传算法引入,对传统遗传算法中初始种群规划和交叉操作进行了优化和改进。仿真实验表明,与最小均方算法、传统遗传算法相比,优化遗传算法对杂波的抑制效果提高了28%,收敛速度提升了3倍,具有良好发展前景。 相似文献
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《船舶与海洋工程学报》2014,(2)
正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas. 相似文献
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《船舶与海洋工程学报》2014,(1)
正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014. 相似文献
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《船舶与海洋工程学报》2014,(1):126-126
正San Francisco,California,June 8-13,2014.OMAE 2014 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to:·meet and present advances in technology and its scientific support;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field. 相似文献
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Lynne Zeitlin Hale Mark Amaral Abdulrahman S. Issa B. A. J. Mwandotto 《Coastal management》2013,41(1):75-85
Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues. 相似文献
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This paper presents a simplified method for the reliability- and the integrity-based optimal design of engineering systems and its application to offshore mooring systems. The design of structural systems is transitioning from the conventional methods, which are based on factors of safety, to more advanced methods, which require calculation of the failure probability of the designed system for each project. Using factors of safety to account for the uncertainties in the capacity (strength) or demands can lead to systems with different reliabilities. This is because the number and arrangement of components in each system and the correlation of their responses could be different, which could affect the system reliability. The generic factors of safety that are specified at the component level do not account for such differences. Still, using factors of safety, as a measure of system safety, is preferred by many engineers because of the simplicity in their application. The aim of this paper is to provide a simplified method for design of engineering systems that directly involves the system annual failure probability as a measure of system safety, concerning system strength limit state. In this method, using results of conventional deterministic analysis, the optimality factors for an integrity-based optimal design are used instead of generic safety factors to assure the system safety. The optimality factors, which estimate the necessary change in average component capacities, are computed especially for each component and a target system annual probability of system failure using regression models that estimate the effect of short and long term extreme events on structural response. Because in practice, it is convenient to use the return period as a measure to quantify the likelihood of extreme events, the regression model in this paper is a relationship between the component demands and the annual probability density function corresponding to every return period. This method accounts for the uncertainties in the environmental loads and structural capacities, and identifies the target mean capacity of each component for maximizing its integrity and meeting the reliability requirement. In addition, because various failure modes in a structural system can lead to different consequences (including damage costs), a method is introduced to compute optimality factors for designated failure modes. By calculating the probability of system failure, this method can be used for risk-based decision-making that considers the failure costs and consequences. The proposed method can also be used on existing structures to identify the riskiest components as part of inspection and improvement planning. The proposed method is discussed and illustrated considering offshore mooring systems. However, the method is general and applicable also to other engineering systems. In the case study of this paper, the method is first used to quantify the reliability of a mooring system, then this design is revised to meet the DNV recommended annual probability of failure and for maximizing system integrity as well as for a designated failure mode in which the anchor chains are the first components to fail in the system. 相似文献
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从确定符合项目实际情况的设计原则入手,通过利比亚米苏拉塔市萨瓦瓦住宅区中心区总体布局和建筑设计两个方面的设计实践,探讨了"传统、现代与文脉"这一当今时代无法回避的文化议题。并且针对具有鲜明文化、宗教和气候特征的建筑设计的特点、方法与风格进行了总结,为今后的实践提供借鉴。 相似文献
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Donna J. Nickerson-Tietze 《Coastal management》2013,41(1):65-74
Fishing communities, the Government of Thailand Department of Fisheries, local nongovermnental organizations, universities, the Food and Agriculture Organization of the United Nations (FAO), and FAO's Bay of Bengal Program have undertaken a partnership in management of Phang-nga Bay's coastal resources. It is the first project of its kind in Thailand, and although still in the early stages, offers insights that may contribute to our knowledge of how we can improve our management of coastal resources, including the importance of (1) building relationships within the governance process; (2) combining education, enforcement, and economic incentives to achieve compliance; (3) implementing solutions early; and (4) government support of community-based decisions. These insights reinforce trends emerging in other coastal management projects in the Asian region. 相似文献