检索结果-内蒙古大学图书馆

Use of an advanced shear-lag model to obtain the optimum internal damping in short-fiber composites

Applied Mechanics Reviews 1989年第11 pt 2期42卷 S93页

作者： Hajela, P. Shih, C.-J. Aerospace Engineering Mechanics and Engineering Science University of Florida Gainesville FL 32611

The present paper examines a modified shear-lag model for predicting the stress distribution in short fiber reinforced composite materials. The model assumes perfect bonding between the fiber and the matrix materials, and allows for the matrix material to partially sustain axial loads. The stress distribution obtained on the basis of this model is used to predict the internal damping characteristics of the composite material. These characteristics are a function of both the material properties and the geometrical layout of the composite, and are optimized by combining the analytical model with a nonlinear programming optimization algorithm. Representative numerical results are obtained for glass–epoxy and graphite–epoxy composites ?1989 The American Society of Mechanical Engineers

关键词： Stress concentration Epoxy adhesives Nonlinear programming optimization algorithms Materials properties Glass Graphite Damping Stress Bonding Composite materials Shear (Mechanics) Epoxy resins Fibers Fiber reinforced composites

来源：评论

学校读者我要写书评

暂无评论

A Generalization Result for Convergence in Learning-to-Optimize

arXiv

引用

arXiv 2024年

作者： Sucker, Michael Ochs, Peter Department of Mathematics University of Tübingen Tübingen Germany Department of Mathematics and Computer Science Saarland University Saarbrücken Germany

Convergence in learning-to-optimize is hardly studied, because conventional convergence guarantees in optimization are based on geometric arguments, which cannot be applied easily to learned algorithms. Thus, we develop a probabilistic framework that resembles deterministic optimization and allows for transferring geometric arguments into learning-to-optimize. Our main theorem is a generalization result for parametric classes of potentially non-smooth, non-convex loss functions and establishes the convergence of learned optimization algorithms to stationary points with high probability. This can be seen as a statistical counterpart to the use of geometric safeguards to ensure convergence. To the best of our knowledge, we are the first to prove convergence of optimization algorithms in such a probabilistic framework. © 2024, CC BY.

关键词： optimization algorithms

来源：评论

学校读者我要写书评

暂无评论

Projection-Based Optimal Mode Scheduling

Projection-Based Optimal Mode Scheduling

引用

IEEE Annual Conference on Decision and Control

作者： T. M. Caldwell T. D. Murphey Department of Mechanical Engineering Northwestern University 2145 Sheridan Road Evanston IL 60208 USA

ISBN: (纸本)9781467357159

This paper develops an iterative optimization technique that can be applied to mode scheduling. The algorithm provides both a mode schedule and timing of that mode schedule with convergence guarantees. Moreover, the algorithm takes advantage of a line search, and the number of iterations in the line search is bounded. There are two key ingredients in the algorithm. First, a projection operation is used that takes arbitrary curves and maps them to feasible switching controls. Second, a descent direction that incorporates the projection is calculated using the mode insertion gradient. Similar to derivative-based finite dimensional optimization, the convergence guarantees and sufficient decrease criteria follow from a local approximation of the cost in the direction of the search direction, but this local approximation is not the standard quadratic approximation. An example demonstrates the steps to implement the optimization algorithm and illustrates convergence.

关键词： line retrieval optimization algorithms Converge iterative methods

来源：评论

学校读者我要写书评

暂无评论

Modified Optimal Control of a Nonlinear Active Suspension System

Modified Optimal Control of a Nonlinear Active Suspension Sy...

引用

2010 49th IEEE Conference on Decision and Control

作者： Tobias Kloiber Guido Koch Boris Lohmann Institute of Automatic Control Technische Universitat Munchen 85748 Garching Germany

ISBN: (纸本)9781424477456

In this paper a new control approach for active vehicle suspensions based on a modified optimal control problem is presented, which considers the nonlinear damper characteristic of a vehicle suspension setup. In this context a new method for the systematic construction of a control Lyapunov function is presented, that is applicable to a class of nonlinear systems. The states that are required by the controller are estimated from the available measurement signals using a nonlinear Kalman filter concept recently presented by the authors. In order to achieve the best possible performance with respect to the conflicting objectives passenger comfort, ride safety and suspension deflection, the controller parameters are determined by means of a multiobjective genetic optimization algorithm. The potential of the controller is demonstrated by comparing it to a conventional linear quadratic regulator. The concept is validated on a quarter-vehicle test rig using measurements of real road profiles as disturbance input.

关键词： Automobile suspensions Controllers Liapunov function Suspension System Active Suspension Systems Optimal control nonlinearity optimization algorithms

来源：评论

学校读者我要写书评

暂无评论

Facial Expression Intensity Estimation Using Ordinal Information

Facial Expression Intensity Estimation Using Ordinal Informa...

引用

IEEE Conference on Computer Vision and Pattern Recognition

作者： Rui Zhao Quan Gan Shangfei Wang Qiang Ji Department of Electrical Computer & Systems Engineering Rensselaer Polytechnic Institute School of Computer Science and Technology University of Science and Technology of China

ISBN: (纸本)9781467388528

Previous studies on facial expression analysis have been focused on recognizing basic expression categories. There is limited amount of work on the continuous expression intensity estimation, which is important for detecting and tracking emotion change. Part of the reason is the lack of labeled data with annotated expression intensity since expression intensity annotation requires expertise and is time consuming. In this work, we treat the expression intensity estimation as a regression problem. By taking advantage of the natural onset-apex-offset evolution pattern of facial expression, the proposed method can handle different amounts of annotations to perform frame-level expression intensity estimation. In fully supervised case, all the frames are provided with intensity annotations. In weakly supervised case, only the annotations of selected key frames are used. While in unsupervised case, expression intensity can be estimated without any annotations. An efficient optimization algorithm based on Alternating Direction Method of Multipliers (ADMM) is developed for solving the optimization problem associated with parameter learning. We demonstrate the effectiveness of proposed method by comparing it against both fully supervised and unsupervised approaches on benchmark facial expression datasets.

关键词： ANNOTATIONS EXPRESSION ANALYSIS Facial Expression Parameter Learning optimization algorithms

来源：评论

学校读者我要写书评

暂无评论

Treatment of Transformers and Voltage Regulators in Branch Current State Estimation for Distribution Networks

Treatment of Transformers and Voltage Regulators in Branch C...

引用

IEEE Power and Energy Society General Meeting

作者： M. Houari I. Kocar F. Therrien J. S. Lacroix école Polytechnique de Montréal QC Canada the University of British Columbia Cooper Power Systems

ISBN: (纸本)9781479913022

The branch current state estimators available in the existing literature consider the distribution networks as composed of lines and cables. In this paper, a general technique is demonstrated in order to handle other key distribution network components such as transformers and voltage regulators. It is also demonstrated how to consider the tap positions of transformers and regulators as state variables in the estimation process given that they are rarely telemetered. The performance of iterative optimization algorithms depends strongly on the initial solution. In this paper, the load allocation algorithm is used in order to obtain an initial solution and associate loads with pseudo-measurements. The latter step is necessary in order to assure observability of the network. The load allocation algorithm used in this study is a straightforward tool based on ladder iterative algorithm.

关键词： Branch currents distribution networks State Estimator (SE) tap position Weighted Least Squares (WLS) Power grids shunt current Transformer Voltage regulators tapping position optimization algorithms load allocation

来源：评论

学校读者我要写书评

暂无评论

Cloud-based Model Predictive Building Thermostatic Controls of Commercial Buildings: Algorithm and Implementation

Cloud-based Model Predictive Building Thermostatic Controls ...

引用

American Control Conference

作者： Emrah Biyik James D. Brooks Hullas Sehgal Jigar Shah Sahika Genc Department of Energy Systems Engineering Yasar University Izmir Turkey GE Global Research Niskayuna NY USA

ISBN: (纸本)9781479917730

The contribution of this paper is in two-folds: 1) If more predictive and intelligent control of the thermostat setpoints with no explicit models of Root Top Units (RTUs) yet with simplistic lumped parameter thermal models of buildings can be effective in reducing a small commercial buildings summer-time peak load while adequately maintaining comfort levels, and 2) how this simplistic indirect control approach to RTUs compare to more sophisticated direct control approaches in terms of peak-load reduction and cost. First, the model-predictive control approach is presented. Second, the results of cloud-based implementation of the optimization algorithm at the two demonstration commercial buildings owned by General Electric (GE), optimizer characteristics, different set point trajectories and their implication with regards to peak load and comfort, and observations are described. On average, the savings from the indirect optimal control strategy utilized in our approach through a cloud-based control implementation architecture is shown to be comparable to previously stated savings in literature from more sophisticated direct optimal control of RTUs while the comfort levels are the same as the non-optimal strategy or slightly better in some cases.

关键词： Comfort level commercial buildings maximum loads optimization algorithms Buildings Direct control Intelligent control COMFORT Optimal control

来源：评论

学校读者我要写书评

暂无评论

Recursive Joint Transmit and Receive Antenna Selection in Spatial Multiplexing Systems

Recursive Joint Transmit and Receive Antenna Selection in Sp...

引用

IEEE Vehicular Technology Conference

作者： Liang Zhou Yoji Ohashi Fujitsu Laboratories Ltd. 4-1-1 Kamikodanaka Nakahara-ku Kawasaki-shi Kanagawa 211-8588 Japan

ISBN: (纸本)9781467363365

In this paper we investigate low complexity joint transmit and receive antenna selection (JTRAS) algorithms for wireless spatial multiplexing (SM) systems. Unlike the conventional JTRAS algorithms that mainly use capacity maximization based criterion, we propose a general method for joint transmit and receive antenna selection according to different selection criteria, including minimum mean square error (MMSE), maximum minimum signal-to-interference-plus-noise ratio (SINR), and maximum capacity. The proposed method for different selection criteria is based on the calculation of matrix inverse and the recursive matrix inverse update is developed to reduce computational complexity. Extensive simulation results show that our algorithms perform very close to the optimal exhaustive search algorithms and better than or equivalent to the suboptimal algorithms in terms of bit error rate (BER) and ergodic capacity in both the uncorrelated and highly correlated MIMO channels, while the computational complexity is much lower than the optimal algorithms.

关键词： Matrix inverse update JTRAS optimum antenna selection spatial multiplexing space division multiplexing multiplex system Receiving antennas Inverse matrix TRANSMITTING optimization algorithms complexity classes Recursive

来源：评论

学校读者我要写书评

暂无评论

Energy-Efficient MIMO Precoding and Power Allocation for Device-to-Device Underlay Communication in Cellular Networks

Energy-Efficient MIMO Precoding and Power Allocation for Dev...

引用

IEEE Vehicular Technology Conference

作者： Bo Chen Minjian Zhao Ming Lei Lei Zhang Department of Information Science and Electronic Engineering Zhejiang University Hangzhou China 310027

ISBN: (纸本)9781479980925

Multiple-input-multiple-output (MIMO) Device-to-Device (D2D) communication underlaying cellular networks can improve user throughout and extend battery life of user equipment. This paper studies MIMO precoding and power allocation schemes for the D2D and cellular uplink communications to improve the energy efficiency of both the D2D and the cellular user (CU). Due to the co-channel interference caused by the shared resources, the precoder design and power allocation of both the D2D transmitter (DTX) and the CU become highly inter-dependent. A distributed cooperative iterative optimization algorithm (DCIOA) is introduced, where either the DTX or the CU cooperatively exchanges the interference information and iteratively updates its optimum precoder and power level. Meanwhile, a centralized stochastic search optimization algorithm using the particle swarm optimization (PSO) method is applied to provide an upper bound. Simulation results show that the performance of the DCIOA is close to that of the centralized algorithm with significant reduction of computation and slight increment of exchange overhead.

关键词： Energy-Efficient D2D Communication MIMO Particle Swarm optimization Distributed Cooperative Iterative optimization Energy efficiency multiple input multiple output systems power splitting Cellular networks Particle swarm optimization Copper Device-to-device communication optimization algorithms prediction coding user facility Battery Life Communication Research Cochannel interference power level

来源：评论

学校读者我要写书评

暂无评论

Multi-objective Design of a Magnetic Fluid Hyperthermia Device

Multi-objective Design of a Magnetic Fluid Hyperthermia Devi...

引用

Annual Conference of the IEEE Industrial Electronics Society

作者： R. Bertani M. Forzan P. Sgarbossa E. Sieni P. Di Barba F. Spizzo L. Del Bianco Dept. Industrial Engineering University of Padova Padova Italy

ISBN: (纸本)9781479917631

The paper presents the design of a new device to heat a magnetic nanofluid in-vivo. The optimal design of the device has been carried by coupling Finite Elements (FE) solutions and various multi-objective optimization algorithms based on Non-dominated Sorting Genetic algorithms (NSGA). The theoretical heating rate of the nanofluid, as resulting from the analytical solution that describes the heating rate in adiabatic conditions, is compared to the one calculated in a FE model that takes into account more real-life thermal conditions.

关键词： Finite element Magnetic fluid hyperthermia optimization Magnetic fluids FINITE ELEMENT Adiabatic conditions Heating Rate optimization algorithms Fever Device Design GTF2E1 gene Iron multi-objective optimal design

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：