检索结果-内蒙古大学图书馆

Power Flow Analysis and Visualization in Smart Grid 8

FTRA 8th International Conference on Multimedia and Ubiquitous Engineering (MUE)

作者： Wu, Dan Wu, Rundong Chen, Zhijian Xie, Wenyan Huang, Xiang Sheng, Bin Liu, Dawei Shanghai Jiao Tong Univ Dept Comp Sci & Engn Shanghai 200030 Peoples R China Guangdong Elect Power Design Inst Network & Informat Branch Guangzhou Guangdong Peoples R China Chinese Acad Sci Inst Software State Key Lab Comp Sci Beijing Peoples R China Xian Jiaotong Liverpool Univ Dept Comp Sci & Software Engn Suzhou Peoples R China

ISBN: (纸本)9783642549007;9783642548994

With the development of society, the requirement for security and economy in power grid is increasing. Hence, the concept of smart grid has been proposed. Smart grid is a new power network, which integrates the technology of advanced sensor measuring, network, communication, calculation and intelligent control. The application of visualization is a significant part in smart grid. On the other hand, the analysis of power flow in power grid is a traditional part in power system. This paper combines power flow analysis with visualization technology in one platform through C programming language. A detailed explanation is given on how to achieve power flow analysis through the classic newton-raphson algorithm and model the power grid with OpenGL programming method in computer. The platform can achieve the function of modeling a power system and dynamic effect in the line.

关键词： Smart grid power flow analysis visualization newton-raphson algorithm OpenGL

来源：评论

学校读者我要写书评

暂无评论

Dynamic MEC Modeling of Claw Pole Alternators

Dynamic MEC Modeling of Claw Pole Alternators

引用

9th International Conference on Ecological Vehicles and Renewable Energies (EVER)

作者： Elloumi, Dhouha Ibala, Amina Rebhi, Rabeb Masmoudi, Ahmed Sfax Engn Sch Res Lab Renewable Energies & Elect Vehicles Sfax Tunisia

ISBN: (纸本)9781479937875

The paper is devoted to the modeling of a claw pole alternator (CPA) following the introduction of a new magnetic equivalent circuit (MEC) which takes into account the variation of the rotor position, leading to the so-called "dynamic MEC". The proposed model considers both linear and saturated behaviors of the magnetic circuit. A special attention is paid to the modeling of the leakage fluxes. A dedicated numerical procedure based on the newton-raphson algorithm has been developed for the resolution of the proposed dynamic MEC. A comparison between the results predicted by the dynamic MEC, under no-load operation, and those of experimental tests carried out on CPA test bench, has led to a good agreement.

关键词： Claw pole alternator dynamic magnetic equivalent circuit leakage flux saturation newton-raphson algorithm back-EMF no-load characteristic

来源：评论

学校读者我要写书评

暂无评论

Fast, Robust and Accurate Digital Image Correlation Calculation Without Redundant Computations

引用

EXPERIMENTAL MECHANICS 2013年第7期53卷 1277-1289页

作者： Pan, B. Li, K. Tong, W. Beijing Univ Aeronaut & Astronaut Inst Solid Mech Beijing 100191 Peoples R China Shanghai Univ Dept Mech Engn Shanghai 200444 Peoples R China So Methodist Univ Dept Mech Engn Dallas TX 75275 USA

High-efficiency and high-accuracy deformation analysis using digital image correlation (DIC) has become increasingly important in recent years, considering the ongoing trend of using higher resolution digital cameras and common requirement of processing a large sequence of images recorded in a dynamic testing. In this work, to eliminate the redundant computations involved in conventional DIC method using forward additive matching strategy and classic newton-raphson (FA-NR) algorithm without sacrificing its sub-pixel registration accuracy, we proposed an equivalent but more efficient DIC method by combining inverse compositional matching strategy and Gauss-newton (IC-GN) algorithm for fast, robust and accurate full-field displacement measurement. To this purpose, first, an efficient IC-GN algorithm, without the need of re-evaluating and inverting Hessian matrix in each iteration, is introduced to optimize the robust zero-mean normalized sum of squared difference (ZNSSD) criterion to determine the desired deformation parameters of each interrogated subset. Then, an improved reliability-guided displacement tracking strategy is employed to achieve further speed advantage by automatically providing accurate and complete initial guess of deformation for the IC-GN algorithm implemented on each calculation point. Finally, an easy-to-implement interpolation coefficient look-up table approach is employed to avoid the repeated calculation of bicubic interpolation at sub-pixel locations. With the above improvements, redundant calculations involved in various procedures (i.e. initial guess of deformation, sub-pixel displacement registration and sub-pixel intensity interpolation) of conventional DIC method are entirely eliminated. The registration accuracy and computational efficiency of the proposed DIC method are carefully tested using numerical experiments and real experimental images. Experimental results verify that the proposed DIC method using IC-GN algorithm and the exist

关键词： Digital image correlation Image matching Sub-pixel displacement Inverse compositional image alignment algorithm newton-raphson algorithm

来源：评论

学校读者我要写书评

暂无评论

Joint hierarchical generalized linear models with multivariate Gaussian random effects

引用

COMPUTATIONAL STATISTICS & DATA ANALYSIS 2013年 68卷 239-250页

作者： Molas, Marek Noh, Maengseok Lee, Youngjo Lesaffre, Emmanuel Erasmus MC Dept Biostat NL-3000 CA Rotterdam Netherlands Pukyong Natl Univ Dept Stat Pusan 608737 South Korea Seoul Natl Univ Dept Stat Seoul 151742 South Korea Katholieke Univ Leuven L Biostat B-3000 Louvain Belgium

Likelihood based inference for correlated data involves the evaluation of a marginal likelihood integrating out random effects. In general this integral does not have a closed form. Moreover, its numerical evaluation might create difficulties especially when the dimension of random effects is high. H-likelihood inference has been proposed where the explicit evaluation of the integral is avoided. The approach also allows extensions handling e.g. (1) complex design experiments, (2) REML type of inference beyond the class of a linear model and (3) overdispersion modeling. The h-likelihood approach to multivariate generalized linear mixed models is extended. The h-likelihood computational algorithms is blended with a newton-raphson procedure for the estimation of the correlation parameters. This allows that components of the joint model are interlinked via correlated Gaussian random effects. Further, correlated random effects are allowed within each component. This approach can serve as a basis for further developments of joint double hierarchical generalized linear models with correlated random effects. The methods are illustrated with a rheumatoid arthritis study dataset, where the correlation between latent trajectories of three endpoints is evaluated. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Joint model H-likelihood Multivariate Gaussian random effects Rheumatoid arthritis newton-raphson algorithm

来源：评论

学校读者我要写书评

暂无评论

How Many Iterations are Sufficient for Efficient Semiparametric Estimation?

引用

SCANDINAVIAN JOURNAL OF STATISTICS 2013年第3期40卷 592-618页

作者： Cheng, Guang Purdue Univ Dept Stat W Lafayette IN 47906 USA

A common practice in obtaining an efficient semiparametric estimate is through iteratively maximizing the (penalized) full log-likelihood w.r.t. its Euclidean parameter and functional nuisance parameter. A rigorous theoretical study of this semiparametric iterative estimation approach is the main purpose of this study. We first show that the grid search algorithm produces an initial estimate with the proper convergence rate. Our second contribution is to provide a formula in calculating the minimal number of iterations k(*) needed to produce an efficient estimate (theta) over cap ((K)(n)*()). We discover that (i) k(*) depends on the convergence rates of the initial estimate and the nuisance functional estimate, and (ii) k(*) iterations are also sufficient for recovering the estimation sparsity in high dimensional data. The last contribution is the novel construction of (theta) over cap ((k))(n) which does not require knowing the explicit expression of the efficient score function. The above general conclusions apply to semiparametric models estimated under various regularizations, for example, kernel or penalized estimation. As far as we are aware, this study provides a first general theoretical justification for the one-/two-step iteration' phenomena observed in the semiparametric literature.

关键词： generalized profile likelihood higher order asymptotic efficiency k-step estimation newton-raphson algorithm semiparametric models

来源：评论

学校读者我要写书评

暂无评论

Towards diffuse optical tomography of arbitrarily heterogeneous turbid medium using GPU-accelerated Monte-Carlo forward

Towards diffuse optical tomography of arbitrarily heterogene...

引用

Conference on Multimodal Biomedical Imaging VIII

作者： Yi, Xi Chen, Weiting Wu, Linhui Zhang, Wei Li, Jiao Wang, Xin Zhang, Limin Zhao, Huijuan Gao, Feng Tianjin Univ Coll Precis Instrument & Optoelect Engn Tianjin 300072 Peoples R China

ISBN: (纸本)9780819493439

At present, the most widely accepted forward model in diffuse optical tomography (DOT) is the diffusion equation, which is derived from the radiative transfer equation by employing the P-1 approximation. However, due to its validity restricted to highly scattering regions, this model has several limitations for the whole-body imaging of small-animals, where some cavity and low scattering areas exist. To overcome the difficulty, we presented a Graphic-Processing-Unit(GPU) implementation of Monte-Carlo (MC) modeling for photon migration in arbitrarily heterogeneous turbid medium, and, based on this GPU-accelerated MC forward calculation, developed a fast, universal DOT image reconstruction algorithm. We experimentally validated the proposed method using a continuous-wave DOT system in the photon-counting mode and a cylindrical phantom with a cavity inclusion.

关键词： diffuse optical tomography Monte-Carlo simulation Graphics Processing Unit newton-raphson algorithm

来源：评论

学校读者我要写书评

暂无评论

Solution of Power Flow With Automatic Load-Frequency Control Devices Including Wind Farms

引用

IEEE TRANSACTIONS ON POWER SYSTEMS 2012年第4期27卷 2186-2195页

作者： Castro, Luis M. Fuerte-Esquivel, Claudio R. Horacio Tovar-Hernandez, J. UMSNH Fac Elect Engn Morelia 58000 Michoacan Mexico Inst Tecnol Morelia Morelia Michoacan Mexico

This paper proposes the integration of steady-state models of several types of wind generators into a power flow algorithm with automatic load-frequency control. Since the system frequency deviation is considered a state variable to be computed by the power flow solution, this formulation helps identify the operating point of wind generators after the action of the primary frequency control when power imbalances have occurred. The mathematical formulation of fixed-speed wind generators is presented based on the steady-state representation of the induction generator. Furthermore, as variable-speed wind generators keep gaining prominence in power systems, their potential contribution to frequency support is also analyzed herein. These models are formulated within the power flow approach by using a unified single frame of reference and the newton-raphson algorithm. The proposed approach is then applied to the analysis of a three-machine, eight-bus system and the IEEE-14 bus test system.

关键词： newton-raphson algorithm power flow analysis primary frequency regulation wind generator

来源：评论

学校读者我要写书评

暂无评论

Accelerating the quadratic lower-bound algorithm via optimizing the shrinkage parameter

引用

COMPUTATIONAL STATISTICS & DATA ANALYSIS 2012年第2期56卷 255-265页

作者： Tian, Guo-Liang Tang, Man-Lai Liu, Chunling Hong Kong Baptist Univ Dept Math Kowloon Tong Hong Kong Peoples R China Univ Hong Kong Dept Stat & Actuarial Sci Hong Kong Hong Kong Peoples R China Hong Kong Polytech Univ Dept Appl Math Kowloon Hong Kong Peoples R China

When the newton-raphson algorithm or the Fisher scoring algorithm does not work and the EM-type algorithms are not available, the quadratic lower-bound (QLB) algorithm may be a useful optimization tool. However, like all EM-type algorithms, the QLB algorithm may also suffer from slow convergence which can be viewed as the cost for having the ascent property. This paper proposes a novel 'shrinkage parameter' approach to accelerate the QLB algorithm while maintaining its simplicity and stability (i.e., monotonic increase in log-likelihood). The strategy is first to construct a class of quadratic surrogate functions Qr(theta vertical bar theta((t))) that induces a class of QLB algorithms indexed by a 'shrinkage parameter' r (r is an element of R) and then to optimize r over R under some criterion of convergence. For three commonly used criteria (i.e., the smallest eigenvalue, the trace and the determinant), we derive a uniformly optimal shrinkage parameter and find an optimal QLB algorithm. Some theoretical justifications are also presented. Next, we generalize the optimal QLB algorithm to problems with penalizing function and then investigate the associated properties of convergence. The optimal QLB algorithm is applied to fit a logistic regression model and a Cox proportional hazards model. Two real datasets are analyzed to illustrate the proposed methods. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Cox proportional hazards model EM-type algorithms Logistic regression newton-raphson algorithm Optimal QLB algorithm QLB algorithm

来源：评论

学校读者我要写书评

暂无评论

Estimation for the three-parameter inverse Gaussian distribution under progressive Type-II censoring

引用

JOURNAL OF STATISTICAL COMPUTATION AND SIMULATION 2012年第7期82卷 1055-1072页

作者： Basak, Prasanta Balakrishnan, N. Penn State Altoona Dept Math & Stat Altoona PA USA McMaster Univ Dept Math & Stat Hamilton ON Canada

Inverse Gaussian distribution has been used widely as a model in analysing lifetime data. In this regard, estimation of parameters of two-parameter (IG2) and three-parameter inverse Gaussian (IG3) distributions based on complete and censored samples has been discussed in the literature. In this paper, we develop estimation methods based on progressively Type-II censored samples from IG3 distribution. In particular, we use the EM-algorithm, as well as some other numerical methods for determining the maximum-likelihood estimates (MLEs) of the parameters. The asymptotic variances and covariances of the MLEs from the EM-algorithm are derived by using the missing information principle. We also consider some simplified alternative estimators. The inferential methods developed are then illustrated with some numerical examples. We also discuss the interval estimation of the parameters based on the large-sample theory and examine the true coverage probabilities of these confidence intervals in case of small samples by means of Monte Carlo simulations.

关键词： progressive Type-II censoring EM-algorithm maximum-likelihood estimates asymptotic variances newton-raphson algorithm confidence intervals coverage probabilities

来源：评论

学校读者我要写书评

暂无评论

MAXIMUM LIKELIHOOD ESTIMATION IN LOG-LINEAR MODELS

引用

ANNALS OF STATISTICS 2012年第2期40卷 996-1023页

作者： Fienberg, Stephen E. Rinaldo, Alessandro Carnegie Mellon Univ Heinz Coll Dept Stat Machine Learning DeptCylab Pittsburgh PA 15213 USA

We study maximum likelihood estimation in log-linear models under conditional Poisson sampling schemes. We derive necessary and sufficient conditions for existence of the maximum likelihood estimator (MLE) of the model parameters and investigate estimability of the natural and mean-value parameters under a nonexistent MLE. Our conditions focus on the role of sampling zeros in the observed table. We situate our results within the framework of extended exponential families, and we exploit the geometric properties of log-linear models. We propose algorithms for extended maximum likelihood estimation that improve and correct the existing algorithms for log-linear model analysis.

关键词： Extended exponential families extended maximum likelihood estimators newton-raphson algorithm log-linear models sampling zeros

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：