检索结果-内蒙古大学图书馆

作者：白瑞北方民族大学

学位级别：硕士

随着遥感影像技术和信息技术的迅速发展,遥感影像数据量呈现快速增长趋势。面对海量的遥感数据,如何利用计算机按照一定规则自动对影像进行分类成为具有挑战性的研究课题。传统的方法是目视解译,该方法需要丰富的专业经验知识,又需要充... 详细信息

随着遥感影像技术和信息技术的迅速发展,遥感影像数据量呈现快速增长趋势。面对海量的遥感数据,如何利用计算机按照一定规则自动对影像进行分类成为具有挑战性的研究课题。传统的方法是目视解译,该方法需要丰富的专业经验知识,又需要充足的户外实地调查资料,而且这种识别方法建立在具有一定的先验知识基础上,所以识别难度大,效率较低。高光谱遥感技术又称为成像光谱遥感技术,具有图像和光谱信息融合的特点,高光谱图像上的每一个像元分别对应一条独特的光谱曲线,因此利用这一性质可以根据地物的光谱反射率来识别遥感影像中的地物类型。同时高光谱图像兼具光学特性和光谱识别能力,已经成为遥感影像领域广泛研究与应用的焦点。遥感图像分类的应用在遥感图像研究中具有重要意义。基于单个特征分类算法对于遥感图像的分类能力是比较有限的,因此为了提高高光谱遥感图像分类的精度,本文提出了基于多特征融合的高光谱遥感分类方法,主要研究工作如下:1.高光谱遥感图像分类方法相关概述。分析了高光谱遥感图像的特征,对前人的高光谱图像特征分类方法进行分析和总结,比较单特征分类方法的不足,提出了基于多特征融合的高光谱遥感图像分类研究。2.经过分析研究发现,遥感图像分类可以从两方面改进:一方面,改进特征;另一方面,改进分类算法。因此本文提出了基于这两方面改进的算法。基于特征改进方法是以现有的特征作为基础,详细介绍纹理特征,直方图特征,降维特征并且利用各类特征的优势,对上述三类特征进行归一化融合,获得融合特征,接着使用AdaBoost集成的三种分类算法Real AdaBoost,Gentle AdaBoost,modest AdaBoost分别对高光谱遥感数据单特征和融合特征进行分类,并且对分类结果进行对比。基于分类算法改进方法是在RVm算法基础上,将局部二值化对比算法(lBPC)和形态学算法(morphologic algorithm)进行改进获得l-m algorithm算法,接着将改进的算法嵌入到RVm算法,然后获得融合特征分类结果。为了使实验更加充分,本文还利用SVm和AdaBoost算法进行分类对比实验。3.分类算法选择。分类算法性能的优劣直接决定着分类效果的好坏,因此,分类算法的选择是高光谱图像分类中的关键一步。实验结果表明,相比于单特征分类精度,融合算法获得的分类精度更高。因此可以得出本文提出的融合算法对于特征分类效果更可靠,更精准的结论。

关键词：遥感图像分类特征提取特征融合 l-m algorithm RVm算法分类精度

来源：评论

学校读者我要写书评

暂无评论

Optimization of WEDm process parameters using deep cryo-treated Inconel 718 as work material

引用

ENGINEERING SCIENCE AND TECHNOlOGY-AN INTERNATIONAl JOURNAl-JESTECH 2016年第1期19卷 161-170页

作者： Nayak, Bijaya Bijeta mahapatra, Siba Sankar Natl Inst Technol Rourkela Dept Mech Engn Rourkela 769008 India

The present work proposes an experimental investigation and optimization of various process parameters during taper cutting of deep cryo-treated Inconel 718 in wire electrical discharge machining process. Taguchi's design of experiment is used to gather information regarding the process with less number of experimental runs considering six input parameters such as part thickness, taper angle, pulse duration, discharge current, wire speed and wire tension. Since traditional Taguchi method fails to optimize multiple performance characteristics, maximum deviation theory is applied to convert multiple performance characteristics into an equivalent single performance characteristic. Due to the complexity and non-linearity involved in this process, good functional relationship with reasonable accuracy between performance characteristics and process parameters is difficult to obtain. To address this issue, the present study proposes artificial neural network (ANN) model to determine the relationship between input parameters and performance characteristics. Finally, the process model is optimized to obtain a best parametric combination by a new meta-heuristic approach known as bat algorithm. The results of the proposed algorithm show that the proposed method is an effective tool for simultaneous optimization of performance characteristics during taper cutting in WEDm process. (C) 2015, Karabuk University. Production and hosting by Elsevier B.V.

关键词： Angular error Bat algorithm Deep-cryogenic treatment maximum deviation theory Taper cutting l-m algorithm

来源：评论

学校读者我要写书评

暂无评论

Study on hologram mosaic algorithm based on Harris corners 7

Study on hologram mosaic algorithm based on Harris corners

引用

7th International Symposium on Precision mechanical measurements (ISPmm)

作者： Yao, Jiabao Tian, Qiuhong Sun, Zhengrong Huang, liu Wang, limin Zhejiang Sci Tech Univ Precis Measurement Lab 928 St 2 Hangzhou 310018 Zhejiang Peoples R China

ISBN: (纸本)9781510601673

To solve the problem of the small field of the view caused by CCD in the process of the hologram record, the hologram mosaic algorithm based on the Harris corners is proposed. The Harris corners in multi-scale are extracted and the mismatching points are removed. The final homography is calculated by using the improved RANSAC algorithm based on l-m algorithm. Finally, the stitched hologram with high quality can be obtained based on the weighted average fusion algorithm. It can overcome the influence to the hologram that the incident angles of the object beam are not consistent. Two experiments carried out with different reconstructed distance demonstrate that the proposed algorithm can realize the measurement of the big object by using the hologram method. Furthermore, it has high accuracy and strong robustness.

关键词： Hologram image mosaic Harris corners homography RANSAC algorithm l-m algorithm

来源：评论

学校读者我要写书评

暂无评论

Reflectarray Probe Optimization at millimeter Frequencies

Reflectarray Probe Optimization at Millimeter Frequencies

引用

European Conference on Antennas and Propagation

作者： álvaro F. Vaquero Daniel R. Prado manuel Arrebola marcos R. Pino Fernando las-Heras Group of Signal Theory and Communications Universidad de Oviedo Spain

ISBN: (纸本)9781509022342

The near field of a reflectarray at 100 GHz is optimized in order to increase the size of the quiet zone for its use in compact antenna test ranges. In order to compute the radiated near field, a simple model of the reflectarray is used in which the field is obtained as contributions of the far field radiated by each unit cell, modeled as a small aperture by means of the second principle of equivalence. Then, the levenberg-marquardt algorithm is employed to optimize both amplitude and phase in order to maximize the size of the quiet zone in different planes. From the obtained phase distribution, a design is carried out. Simulations are compared for the near field before and after the optimization, showing an important improvement of the size of the quiet zone in the main cuts of the near field.

关键词： Near field optimization Compact Antenna Test Range (CATR) levenberg-marquardt algorithm reflectarray quiet zone l-m algorithm near-field unit cell millimeter Phase distribution NATIONAl EmERGENCY AlARm REPEATER far-field

来源：评论

学校读者我要写书评

暂无评论

leveraging Prior State in 3-D Full-Wave RF Imaging via levenberg-marquardt algorithm

Leveraging Prior State in 3-D Full-Wave RF Imaging via Leven...

引用

Computational Electromagnetics International Workshop (CEm)

作者： muniganti, Harikiran Gope, Dipanjan Indian Inst Sci Dept Elect Commun Engn Bangalore 560012 Karnataka India

Sensitivity of initial guess while using levenberg-marquardt algorithm in solving the inverse problem for 3-D radio frequency (RF) imaging is studied. It is shown that the prior state as initial guess can be leveraged... 详细信息

ISBN: (纸本)9781467371971

关键词： l-m algorithm radiofrequency Guess full-wave Inverse method Imaging Three Dimensions

来源：评论

学校读者我要写书评

暂无评论

Short-term load Prediction of Power System Based on Genetic Neural Network

Short-term Load Prediction of Power System Based on Genetic ...

引用

2015 International Industrial Informatics and Computer Engineering Conference(IIICEC 2015)

作者： Shiwei li Yulong li School of electronic and information engineering Lan Zhou Jiao Tong University Experiment center on computer science Lan Zhou Jiao Tong University

As the basic content of power system's operation management and real-time control,the short-term load forecasting is significant for power system to run safely and economically.A short-term power system load predicting model based on genetic neural network is proposed,which take many factors into account,such as temperature,holidays and so *** order to solve the problems of long convergence time and being easy to fall into local minimum of BP neural network,genetic algorithm(GA) is used to make a global searching for the initial weights and thresholds to solve the problems of long convergence time of BP neural network,and the levenberg-marquardt(l-m) method is used to train the network *** on the historical actual data,the forecasting results by the proposed method is more precise than those by BP neural network model,providing an effective way to forecast short-term power system load.

关键词： Genetic algorithm Neural network l-m algorithm Power system load forecasting

来源：评论

学校读者我要写书评

暂无评论

Recognition of solar cell modules defects based on optimized BP neural network

Recognition of solar cell modules defects based on optimized...

引用

第五届国际自动化测试与仪器仪表学术会议

作者： Wang Yongqing Tian Dan Chen Wenjun Song Dengyuan Wang Shuonan Tong Qiang Key Laboratory of Digital Medical Engineering of Hebei Province College of Electronic and Information EngineeringHebei University Yingli Energy(China)Co.Ltd

Since the standard BP algorithm to recognize the defects of solar cell modules have the problem of slow convergence speed and easily falls into relative *** recognition method which based on optimized algorithm is *** preprocessing image of electroluminescence infrared image of solar cell component in debris,crack,off-grid,open weld and black pieces,extracting 5 combined invariant moments of the defect as the input of BP neural *** network of the BP algorithm with additional momentum,l-m algorithm and standard BP algorithm are used to performance comparison in recognition *** results indicate that,the BP neural network of l-m algorithm have the advantages of fast convergence speed and high *** recognition rate of 5 kinds of defect has reached more than 90%.

关键词： Solar cell modules infrared image defect BP neural network l-m algorithm

来源：评论

学校读者我要写书评

暂无评论

Novel Automatic Digital Calibration Techniques for GmR Sensors

Novel Automatic Digital Calibration Techniques for GMR Senso...

引用

IEEE Sensors

作者： Antonio J. lopez-martin Alfonso Carlosena Dept. of Electrical and Electronic Engineering Public University of Navarra Pamplona Spain

ISBN: (纸本)9781479901609

Simple and innovative automatic techniques for digital calibration of Giant magnetoresistive (GmR) sensor bridges are presented, which allow compensating the main problems of these devices: temperature dependence, sensitivity variations, nonlinearity, electrical offset and mechanical misalignments. They are based on obtaining the best fit of the GmR bridge output with a sinusoid using the levenberg-marquardt algorithm, and thus generating the optimal gain, electrical offset and mechanical offset compensation. Gain and offset temperature drifts are also digitally compensated by sensing temperature from the GmR bridge itself. Nonlinearity is removed using a very simple logic that exploits the symmetry and weak nonlinearity of the GmR output. The digital calibration techniques have been used in a contactless angular detection system developed by the authors. measurement results show that digital calibration reduces maximum errors from 7.2° to less than 1° in an angular range of 110°.

关键词： digital correction Giant magnetoresistance calibration technique nonlinearity maximum error Sinusoidal Beds l-m algorithm digitally Detection systems

来源：评论

学校读者我要写书评

暂无评论

Damage mechanisms in Copper-Aluminum Wirebond Under High Temperature Operation

Damage Mechanisms in Copper-Aluminum Wirebond Under High Tem...

引用

IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

作者： Pradeep lall Shantanu Deshpande luu Nguyen masood murtuza Auburn University NSF-CAVE3 Electronic Research Center Department of Mechanical Engineering Texas Instruments

ISBN: (纸本)9781479952687

Wire bonding is predominant mode of interconnect in electronics packaging. Traditionally material used for wire bonding is gold. But industry is slowly replacing gold wire bond by copper-aluminum wire bond because of the lower cost and better mechanical properties than gold, such as high strength, high thermal conductivity etc. Numerous studies have been done to analyze failure mechanism of Cu-Al wire bonds. Cu-Al interface is a predominant location for failure of the wirebond interconnects. In this paper, the use of intermetallic thickness as leading indicator-of-failure for prognostication of remaining useful life for Cu-Al wire bond interconnects has been studied. For analysis, 32 pin chip scale packages were used. Packages were aged isothermally at 200℃ and 250℃ for 10 days. Packages were withdrawn periodically after 24 hours and its ImC thickness was measured using SEm. The parts have been prognosticated for accrued damage and remaining useful life in current or anticipated future deployment environment. The presented methodology uses evolution of the ImC thickness in conjunction with the levenberg-marquardt algorithm to identify accrued damage in wire bond subjected to thermal aging. The proposed method can be used for equivalency of damage accrued in Cu-Al parts subjected to multiple thermal aging environments.

关键词： wire bonding remaining service life collapse mechanism ElECTRIC WIRE packages High temperature operations Bond Gold l-m algorithm HEAT AGEING bonding

来源：评论

学校读者我要写书评

暂无评论

RADIO INTERFEROmETRIC CAlIBRATION USING A RIEmANNIAN mANIFOlD

RADIO INTERFEROMETRIC CALIBRATION USING A RIEMANNIAN MANIFOL...

引用

IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Sarod Yatawatta ASTRON The Netherlands Institute for Radio Astronomy The Netherlands.

ISBN: (纸本)9781479903573

In order to cope with the increased data volumes generated by modern radio interferometers such as lOFAR (low Frequency Array) or SKA (Square Kilometre Array), fast and efficient calibration algorithms are essential. Traditional radio interferometric calibration is performed using nonlinear optimization techniques such as the levenberg-marquardt algorithm in Euclidean space. In this paper, we reformulate radio interferometric calibration as a nonlinear optimization problem on a Riemannian manifold. The reformulated calibration problem is solved using the Riemannian trust-region method. We show that calibration on a Riemannian manifold has faster convergence with reduced computational cost compared to conventional calibration in Euclidean space.

关键词： Calibration Interferometry: Radio interferometry Calibration Euclidean space manifolds Radio l-m algorithm radio interferometer

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：