检索结果-内蒙古大学图书馆

Hybrid Full Frequency Precoding for Integrated Remote Wireless Sensor and Multibeam Satellite Networks

KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 2016年第6期10卷 2546-2566页

作者： Li, Hongjun Dong, Feihong Gong, Xiangwu Deng, Changliang Jia, Luliang Wang, Jingchao PLA Univ Sci & Technol Coll Commun Engn Nanjing 210007 Peoples R China Inst China Elect Syst Engn Co Beijing 100141 Peoples R China PLAAF 95899 Unit Beijing 100085 Peoples R China

This paper investigates an efficient transmission scheme for the remote wireless sensors to receive information which is rarely discussed in the integrated remote wireless sensor and multibeam satellite networks (IWSMSNs). The networks can be employed to exchange sensing information for emergency scenario, ocean scenario, and so on, which are isolated from available terrestrial networks. As the efficient transmission link is important to the IWSMSNs, we propose a hybrid full frequency (HFF) precoding by taking advantage of frequency reuse and multiple-input multiple-output (MIMO) precoding. Considering energy efficiency and sinks fairness are crucial to transmission link, thus the HFF precoding problems are formulated as transmit power minimization (TPM) and max-min fair (MMF) received signal to interference plus noise ratio (SINR) problems, which can be transformed to indefinite quadratic optimization programs. Then this paper presents a semi-definite programming (SDP) algorithm to solve the problems for the IWSMSNs. The promising potential of HFF for the real IWSMSNs is demonstrated through simulations.

关键词： hybrid full frequency precoding multiple-input multiple-output integrated remote wireless sensor and multibeam satellite networks semi-definite programming

来源：评论

学校读者我要写书评

暂无评论

Convex Relaxation of Optimal Power Flow in Distribution Feeders with Embedded Solar Power

引用

Energy Procedia 2016年 100卷 43-49页

作者： Alexander Hermann Qiuwei Wu Shaojun Huang Arne Hejde Nielsen Center for Electric Power and Energy Technical Univeristy of Denmark Elektrovej Building 325 2800 Lyngby Denmark

There is an increasing interest in using Distributed Energy Resources (DER) directly coupled to end user distribution feeders. This poses an array of challenges because most of today's distribution feeders are designed for unidirectional power flow. Therefore when installing DERs such as solar panels with uncontrolled inverters, the upper limit of installable capacity is quickly reached in many of today's distribution feeders. This problem can often be mitigated by optimally controlling the voltage angles of inverters. However, the optimal power flow problem in its standard form is a large scale non-convex optimization problem, and thus can’t be solved precisely and also is computationally heavy and intractable for large systems. This paper examines the use of a convex relaxation using semi-definite programming to optimally control solar power inverters in a distribution grid in order to minimize the global line losses of the feeder. The mathematical model is presented in details. Further, case studies are completed with simulations involving a 15-bus radial distribution system. These simulations are run for 24 hour periods, with actual solar data and demand data.

关键词： semi-definite programming Optimal Power Flow Convex Relaxation 15 bus test feeder

来源：评论

学校读者我要写书评

暂无评论

Matrix Completion Optimization for Localization in Wireless Sensor Networks for Intelligent IoT

引用

SENSORS 2016年第5期16卷 722-722页

作者： Nguyen, Thu L. N. Shin, Yoan Soongsil Univ Sch Elect Engn Seoul 156743 South Korea

Localization in wireless sensor networks (WSNs) is one of the primary functions of the intelligent Internet of Things (IoT) that offers automatically discoverable services, while the localization accuracy is a key issue to evaluate the quality of those services. In this paper, we develop a framework to solve the Euclidean distance matrix completion problem, which is an important technical problem for distance-based localization in WSNs. The sensor network localization problem is described as a low-rank dimensional Euclidean distance completion problem with known nodes. The task is to find the sensor locations through recovery of missing entries of a squared distance matrix when the dimension of the data is small compared to the number of data points. We solve a relaxation optimization problem using a modification of Newton's method, where the cost function depends on the squared distance matrix. The solution obtained in our scheme achieves a lower complexity and can perform better if we use it as an initial guess for an interactive local search of other higher precision localization scheme. Simulation results show the effectiveness of our approach.

关键词： Internet of Things wireless sensor network localization Euclidean distance matrix completion semi-definite programming modified Newton method

来源：评论

学校读者我要写书评

暂无评论

Robust Transmit Code and Receive Filter Design for Extended Targets in Clutter

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2015年第8期63卷 1965-1976页

作者： Karbasi, Seyyed Mohammad Aubry, Augusto De Maio, Antonio Bastani, Mohammad Hasan Sharif Univ Technol Fac Elect Engn Tehran *** Iran CNR IREA I-80124 Naples Italy Univ Naples Federico II Dipartimento Ingn Elettr & Tecnol Informaz I-80125 Naples Italy

We propose a novel robust design method to jointly optimize the radar transmit code and receive filter, exploiting the Signal-to-Interference plus Noise Ratio (SINR) at the receiver end as design figure of merit. We confer robustness to our method against uncertainties on the target impulse response (TIR) using a worst-case optimization approach based on two different uncertainty sets. The former is composed of a finite collection of TIRs, obtained by sampling the actual TIR at some aspect angles;the latter is a spherical uncertainty set. We further enforce a peak-to-average power ratio (PAR) constraint to the transmit code, which is very important for radar applications where the transmitter operates close to saturation. The design problem is tackled using a sequential optimization procedure alternating between two semi-definite programming (SDP) problems, followed by randomization steps. Our numerical results highlight the robustness and applicability of the proposed method in different scenarios.

关键词： Extended target model PAR constraint robust design semi-definite programming signal-dependent interference

来源：评论

学校读者我要写书评

暂无评论

ON CONVEXITY AND IDENTIFIABILITY IN 1-D FOURIER PHASE RETRIEVAL

ON CONVEXITY AND IDENTIFIABILITY IN 1-D FOURIER PHASE RETRIE...

引用

IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Kejun Huang Yonina C. Eldar Nicholas D. Sidiropoulos University of Minnesota Minneapolis MN 55455 USA Technion - Israel Institute of Technology Haifa 32000 Israel

ISBN: (纸本)9781479999897

This paper considers phase retrieval from the magnitude of 1 -D over-sampled Fourier measurements. We first revisit the well-known lack of identifiability in this case, and point out that there always exists a solution that is minimum phase, even though the desired signal is not. Next, we explain how the least-squares formulation of this problem can be optimally solved via PhaseLift followed by spectral factorization, and this solution is always minimum phase. A simple approach is then proposed to circumvent non-identifiability: adding an impulse to an arbitrary complex signal (offset to the Fourier transform) before taking the quadratic measurements, so that a minimum phase signal is constructed and thus can be uniquely estimated. Simulations with synthetic data show the effectiveness of the proposed method.

关键词： phase retrieval over-sampled Fourier measurements minimum phase auto-correlation estimation semi-definite programming

来源：评论

学校读者我要写书评

暂无评论

An Unsupervised Learning Approach for Facial Expression Recognition using semi-definite programming and Generalized Principal Component Analysis

An Unsupervised Learning Approach for Facial Expression Reco...

引用

Conference on Image Processing - Algorithms and Systems VIII

作者： Gholami, Behnood Haddad, Wassim M. Tannenbaum, Allen R. Georgia Inst Technol Sch Aerosp Engn Atlanta GA 30332 USA Georgia Inst Technol Sch Elect & Comp & Biomed Engn Atlanta GA 30332 USA

ISBN: (纸本)9780819479259

In this paper, we consider facial expression recognition using an unsupervised learning framework. Specifically, given a data set composed of a number of facial images of the same subject with different facial expressions, the algorithm segments the data set into groups corresponding to different facial expressions. Each facial image can be regarded as a point in a high-dimensional space, and the collection of images of the same subject resides on a manifold within this space. We show that different facial expressions reside on distinct subspaces if the manifold is unfolded. In particular, semi-definite embedding is used to reduce the dimensionality and unfold the manifold of facial images. Next, generalized principal component analysis is used to fit a series of subspaces to the data points and associate each data point to a subspace. Data points that belong to the same subspace are shown to belong to the same facial expression.

关键词： Facial expression recognition unsupervised learning dimension reduction semi-definite programming manifold unfolding principal component analysis

来源：评论

学校读者我要写书评

暂无评论

On minimizing a quadratic function on Stiefel manifold

引用

LINEAR ALGEBRA AND ITS APPLICATIONS 2015年 475卷 251-264页

作者： Dodig, Marija Stogic, Marko Xavier, Joao Univ Lisbon CEAFEL Ctr Anal Func Estruturas Lineares & Aplicacoe P-1649003 Lisbon Portugal SANU Math Inst Belgrade 11000 Serbia Inst Super Tecn Inst Sistemas & Robot P-1049001 Lisbon Portugal Inst Super Tecn CAMGSD P-1049001 Lisbon Portugal

In this paper we propose a novel approach to a particular quadratic programming problem, when the optimization is performed over the set O(3,2) of 3 x 2 Stiefel matrices. We rewrite the original nonconvex problem as a semi-definite programming problem, by computing a convex hull (tight convex relaxation) of a certain set of matrices. We give an efficient, quick algorithm for the minimization of a quadratic function over Stiefel manifold. We report some numerical experiments to illustrate the tightness of the convex approximation obtained by the two aforementioned methods ("standard" and ours). Our result is of immediate interest in Computer Vision, including Structure-from-Motion (SfM) problems, and 2D-3D registration. (C) 2015 Elsevier Inc. All rights reserved.

关键词： Quadratic programming semi-definite programming Convex hull Stiefel matrix

来源：评论

学校读者我要写书评

暂无评论

A semi-definite Relaxation Approach for Partial Discharge Source Location in Transformers

引用

IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2015年第2期22卷 1097-1104页

作者： Zeng, Fuping Tang, Ju Huang, Liang Wang, Wei Wuhan Univ Sch Elect Engn Wuhan 430072 Peoples R China State Key Lab Power Transmiss Equipment & Syst Se Chongqing 400044 Peoples R China North China Elect Power Univ Beijing Key Lab High Voltage & EMC Beijing 102206 Peoples R China

Current issues on localization algorithms based on the time difference of arrival (TDOA) for the partial discharge (PD) source include its sensitivity to time delay error, easy local convergence or divergence, and the large amount of computational load and time. A semi-definite relaxation method for PD source location to solve the time delay positioning equations is proposed in this paper, which using the semi-definite programming problem has the characteristic that can ensure obtained the global optimal solution. The proposed method converts nonlinear time delay equations into an equivalent semi-definite programming (SDP) problem by equivalent transformation and rank-1 relaxation firstly. Then use the interior point algorithm to solve the SDP problem that to obtain a unique global optimum solution, and extract a rank-1 component from the global optimal solution of relaxed SDP. Finally, to serve as a good approximate of the original problem for the PD location. The method was used to localize a measured PD source signal in the laboratory, and the results were compared with those of positioning by the Newton-iterative method. The comparison showed that the method can reduce sensitivity for the time delay error as well as effectively solve TDOA location equations, thereby ensuring that the result is a unique global optimal solution with high positioning efficiency. The localization algorithm problem is solved with the unavoidable and difficult-to-locate time delay error.

关键词： Partial discharge nonlinear time-difference equations semi-definite programming semi-definite relaxation global optimum solution

来源：评论

学校读者我要写书评

暂无评论

Sum-of-squares of polynomials approach to nonlinear stability of fluid flows: an example of application

引用

PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 2015年第2183期471卷 1-18页

作者： Huang, D. Chernyshenko, S. Goulart, P. Lasagna, D. Tutty, O. Fuentes, F. Univ London Imperial Coll Sci Technol & Med Dept Aeronaut Prince Consort Rd London SW7 2AZ England Univ Oxford Dept Engn Sci Oxford OX1 3PJ England Univ Southampton Engn & Environm Southampton SO17 1BJ Hants England Univ Texas Austin ICES Austin TX 78712 USA

With the goal of providing the first example of application of a recently proposed method, thus demonstrating its ability to give results in principle, global stability of a version of the rotating Couette flow is examined. The flow depends on the Reynolds number and a parameter characterizing the magnitude of the Coriolis force. By converting the original Navier-Stokes equations to a finite-dimensional uncertain dynamical system using a partial Galerkin expansion, high-degree polynomial Lyapunov functionals were found by sum-of-squares of polynomials optimization. It is demonstrated that the proposed method allows obtaining the exact global stability limit for this flow in a range of values of the parameter characterizing the Coriolis force. Outside this range a lower bound for the global stability limit was obtained, which is still better than the energy stability limit. In the course of the study, several results meaningful in the context of the method used were also obtained. Overall, the results obtained demonstrate the applicability of the recently proposed approach to global stability of the fluid flows. To the best of our knowledge, it is the first case in which global stability of a fluid flow has been proved by a generic method for the value of a Reynolds number greater than that which could be achieved with the energy stability approach.

关键词： flow stability rotating Couette flow Lyapunov function sum-of-squares of polynomials semi-definite programming

来源：评论

学校读者我要写书评

暂无评论

Highlighting data clusters by graph embedding

引用

NEUROCOMPUTING 2015年 165卷 75-80页

作者： Li, Wenye Macao Polytech Inst Cathedral Parish Macao Sar Peoples R China

We propose a novel method, modularity embedding, to embed high-dimensional data or graphs in a low-dimensional space. Central to our work is a model that quantifies the relationship of two data points by their pairwise modular value. A larger value indicates a higher chance that they should be placed near to each other, and vice versa. The objective function of the model has a simple formulation of minimizing the sum of squared distances between data points weighted by pairwise modular values. It is naturally relaxed as a semi-definite program that learns a low-rank kernel matrix with only one linear constraint, which can be solved efficiently by modern mathematical optimization solvers. Compared with traditional graph embedding algorithms, the proposed method is shown to be able to highlight cluster structures inherent in high-dimensional data and graphs, which provides a promising tool in data analysis applications. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Clustering Graph embedding semi-definite programming

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：