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关键词

遗传算法 2

MapReduce;近似作业;时限;任务调度;掉队任务消除 1

三维构造 1

优化 1

供水泵站 1

函数逼近能力 1

协议关系 1

同步扰动随机逼近 1

地质曲面 1

均匀流形逼近和投影 1

多源地质数据 1

安全性第一准则 1

对象跟踪 1

广义哈密尔顿—雅可比—贝尔曼方程;非线性最优控制;伽辽金逼近(Galerkin approximation);勒让德多项式(Legendre polynomials) 1

广义近似空间 1

强化学习 1

插值—逼近拟合 1

数值拟合 1

模糊系统 1

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A case study on sample average approximation method for stochastic supply chain network design problem

Yuan WANG, Ruyan SHOU, Loo Hay LEE, Ek Peng CHEW

《工程管理前沿(英文)》 2017年 第4卷 第3期   页码 338-347 doi: 10.15302/J-FEM-2017032

摘要: This study aims to solve a typical long-term strategic decision problem on supply chain network design with consideration to uncertain demands. Existing methods for these problems are either deterministic or limited in scale. We analyze the impact of uncertainty on demand based on actual large data from industrial companies. Deterministic equivalent model with nonanticipativity constraints, branch-and-fix coordination, sample average approximation (SAA) with Bayesian bootstrap, and Latin hypercube sampling were adopted to analyze stochastic demands. A computational study of supply chain network with front-ends in Europe and back-ends in Asia is presented to highlight the importance of stochastic factors in these problems and the efficiency of our proposed solution approach.

关键词: supply chain network     stochastic demand     sampling average approximation     Bayesian bootstrap     Latin hypercube sampling    

Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 17-22 doi: 10.1007/s11465-008-0015-4

摘要: To reconstruct the shape of the scatterer in elastic media, the authors deduce the Born approximation solution of the two-dimensional scattering problem, which includes the shape factor that embodies all information about the shape of the scatterer. Accordingly, the change in the shape of the scatterer only necessitates the number of the corresponding new shape factors. For a parallelogram void in a long Al rod, its shape factor can be obtained. In view of the definition of a characteristic function, the shape factor has a corresponding integral representation. Obviously, the shape factor can be considered as a Fourier transform of the characteristic function, which is reconstructed from the inverse Fourier transform. The integral equation is considered as the basic equation to reconstruct the shape of the scatterer. The identification of the geometrical character of a flaw is then given by the two dimensional inverse Born approximation in a low-frequency range. For the parallelogram void, a theoretical calculating identification is performed. At the same time, the numerical results are obtained by the finite element method.

关键词: approximation     scatterer     scattering problem     information     inverse    

广义近似空间与粗糙分类代数

刘永红

《中国工程科学》 2006年 第8卷 第3期   页码 39-48

摘要:

提出了广义近似空间、粗近似公理、干扰集公理、粗糙集的分类原则、粗选原则、不确定偶集原则、精选原则、对策分类、量子逻辑分类、bit量子对称分类、不可比集、bit空间集、协议关系、粗糙集函数、粗糙分类代数和粗糙单代数等基本概念,并提出了一个猜想;展示了一些新观点;基于协议关系构造了粗糙商代数和粗糙子代数,给出了回避-归并算法及算例。

关键词: 广义近似空间     粗糙集     粗糙分类代数     协议关系     粗糙单代数     粗糙商代数     粗糙子代数    

连续非线性最优控制问题的勒让德—伽辽金逼近方法 Article

Xue-song CHEN

《信息与电子工程前沿(英文)》 2017年 第18卷 第10期   页码 1479-1487 doi: 10.1631/FITEE.1601101

摘要: 该方法基于伽辽金逼近理论(Galerkin approximation)求解广义哈密尔顿—雅可比—贝尔曼(Hamilton-Jacobi-Bellman, GHJB)方程。

关键词: 广义哈密尔顿—雅可比—贝尔曼方程;非线性最优控制;伽辽金逼近(Galerkin approximation);勒让德多项式(Legendre polynomials)    

满足MapReduce环境下近似处理的时限要求 Article

Ming-hao HU, Chang-jian WANG, Yu-xing PENG

《信息与电子工程前沿(英文)》 2017年 第18卷 第11期   页码 1754-1772 doi: 10.1631/FITEE.1601056

摘要: 为了向大数据分析提供实时结果,在现今的生产环境中满足MapReduce作业的时限要求是非常关键的。许多研究致力于解决时限要求的问题,目前存在两种代表性的方法。第一种是分配适量资源以在时限前完成整个作业,在时限紧迫或资源受限时,该方法会错过时限;另一种是在时限约束下运行预数据量的样本,该方法能满足时限但无法使数据量最大化。在本文中,我们提出一个时限–导向的任务调度方法来解决上述问题,称为“Dart”。给定具体的时限和可用资源量时,Dart使用基于历史数据和作业运行状态的迭代估计法准确预测作业完成时间。基于时间预测,Dart法采用接近–修改算法做出动态调度决策,在满足时限的情况下将可处理数据量最大化并消除掉队任务。同时Dart法可有效地避免任务失败和数据倾斜,防止其性能受影响。在包含64个虚拟机的集群上使用OpenCloud和Facebook的工作负载对Dart法进行评估。结果表明Dart法在时限紧迫和资源受限情况下能有效满足时限并将处理数据量最大化。

关键词: MapReduce;近似作业;时限;任务调度;掉队任务消除    

Approximation of structural damping and input excitation force

Mohammad SALAVATI

《结构与土木工程前沿(英文)》 2017年 第11卷 第2期   页码 244-254 doi: 10.1007/s11709-016-0371-9

摘要: Structural dynamic characteristics are the most significant parameters that play a decisive role in structural damage assessment. The more sensitive parameter to the damage is the damping behavior of the structure. The complexity of structural damping mechanisms has made this parameter to be one of the ongoing research topics. Despite all the difficulties in the modeling of damping, there are some approaches like as linear and nonlinear models which are described as the energy dissipation throughout viscous, material or structural hysteretic and frictional damping mechanisms. In the presence of a mathematical model of the damping mechanisms, it is possible to estimate the damping ratio from the theoretical comparison of the damped and un-damped systems. On the other hand, solving the inverse problem of the input force estimation and its distribution to each SDOFs, from the measured structural responses plays an important role in structural identification process. In this paper model-based damping approximation method and a model-less structural input estimation are considered. The effectiveness of proposed methods has been carried out through analytical and numerical simulation of the lumped mass system and the results are compared with reference data. Consequently, high convergence of the comparison results illustrates the satisfactory of proposed approximation methods.

关键词: structural modal parameters     damping identification method     input excitation force identification     Inverse problem    

复杂地质曲面三维插值—逼近拟合构造方法

李明超,缪正建,刘菲,王刚

《中国工程科学》 2011年 第13卷 第12期   页码 103-107

摘要:

针对水利水电工程多源地质数据的特点,充分考虑了地质精度要求、曲面连续性和数据存储量等多方面的均衡,提出并实现了基于NURBS(non-uniform rational B-splines,非均匀有理样条曲线)技术的复杂地质曲面插值—逼近拟合构造方法。该方法对于工程关键区域集中且均匀分布的原始数据,采用NURBS蒙皮插值方法,使曲面严格通过这些数据点;对于周边区域分布离散的数据,采用NURBS逼近拟合方法,使曲面在给定精度下充分逼近原始数据;最后对整体曲面的地质结构合理性、几何性和精度进行检查分析和调整。实例表明,该方法所构造的地质曲面能满足地质工程师的实际需要,并能为进一步的三维地质建模提供基础。

关键词: 地质曲面     插值—逼近拟合     三维构造     多源地质数据    

Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

《能源前沿(英文)》 2008年 第2卷 第1期   页码 116-120 doi: 10.1007/s11708-008-0019-0

摘要: A combustion instability detection method that uses the wavelet detail of combustion pressure fluctuations is put forward. To confirm this method, combustion pressure fluctuations in a stoker boiler are recorded at stable and unstable combustion with a pressure transducer. Daubechies one-order wavelet is chosen to obtain the wavelet details for comparison. It shows that the wavelet approximation indicates the general pressure change in the furnace, and the wavelet detail magnitude is consistent with the intensity of turbulence and combustion noise. The magnitude of the wavelet detail is nearly constant when the combustion is stable, however, it will fluctuate much when the combustion is unstable.

关键词: comparison     wavelet approximation     pressure transducer     general pressure     consistent    

Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 294-301 doi: 10.1007/s11465-010-0019-8

摘要: The traditional pseudo-rigid-body model (PRBM) has one degree of freedom (DOF) and performs a good simulation to the tip locus of flexible links for compliant mechanisms on the basis of a parametric approximation method. In this study, a new approach of a two-DOF PRBM is proposed to simulate both the tip locus and tip deflection angle of large-deflection links for compliant mechanisms on the basis of the angular deflection approximation technique. A linear regression for the spring stiffness coefficient of the 2R PRBM using the optimization technique is presented. The advantage of the new model is well illustrated through a numerical comparison between the 1R and the 2R PRBM.

关键词: compliant mechanism     pseudo-rigid-body model (PRBM)     large-deflection link     angular deflection approximation    

Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 852-862 doi: 10.1007/s11709-019-0522-x

摘要: Due to an increased need in hydro-electricity, water storage, and flood protection, it is assumed that a series of new dams will be build throughout the world. The focus of this paper is on the non-probabilistic-based design of new arch-type dams by applying means of robust design optimization (RDO). This type of optimization takes into account uncertainties in the loads and in the material properties of the structure. As classical procedures of probabilistic-based optimization under uncertainties, such as RDO and reliability-based design optimization (RBDO), are in general computationally expensive and rely on estimates of the system’s response variance, we will not follow a full-probabilistic approach but work with predefined confidence levels. This leads to a bi-level optimization program where the volume of the dam is optimized under the worst combination of the uncertain parameters. As a result, robust and reliable designs are obtained and the result is independent from any assumptions on stochastic properties of the random variables in the model. The optimization of an arch-type dam is realized here by a robust optimization method under load uncertainty, where hydraulic and thermal loads are considered. The load uncertainty is modeled as an ellipsoidal expression. Comparing with any traditional deterministic optimization method, which only concerns the minimum objective value and offers a solution candidate close to limit-states, the RDO method provides a robust solution against uncertainty. To reduce the computational cost, a ranking strategy and an approximation model are further involved to do a preliminary screening. By this means, the robust design can generate an improved arch dam structure that ensures both safety and serviceability during its lifetime.

关键词: arch dam     shape optimization     robust optimization     load uncertainty     approximation model    

Nonlinear dynamics of a wind turbine tower

A. GESUALDO, A. IANNUZZO, F. PENTA, M. MONACO

《机械工程前沿(英文)》 2019年 第14卷 第3期   页码 342-350 doi: 10.1007/s11465-019-0524-3

摘要: The recent proliferation of wind turbines has revealed problems in their vulnerability under different site conditions, as evidenced by recent collapses of wind towers after severe actions. Analyses of structures subjected to variable actions can be conducted through several methods with different accuracy levels. Nonlinear dynamics is the most reliable among such methods. This study develops a numerical procedure to obtain approximate solutions for rigid-plastic responses of structures subjected to base harmonic pulses. The procedure’s model is applied to a wind turbine tower subjected to inertial forces generated by harmonic ground acceleration, and failure is assumed to depend on the formation of shear hinges. The proposed approach provides an efficient representation of the post-elastic behavior of the structure, has a low computational cost and high effectiveness, and uses a limited number of mechanical parameters.

关键词: nonlinear dynamics     plastic shear failure     modal approximation     time history    

任意隶属度函数模糊系统的逼近特性

张钊,裴燕玲,郑爱红

《中国工程科学》 2005年 第7卷 第8期   页码 47-50

摘要:

以四边形隶属函数作为一般的隶属函数,利用Stone-Weierstrass定理对任意隶属函数的模糊系统任意逼近紧集上的任意连续实函数进行证明,是对基本模糊系统逼近任意连续非线性函数理论的推广,模糊系统对任意非线性函数的逼近性能,是模糊系统用于系统辩识的理论依据。

关键词: 模糊系统     隶属函数     逼近    

Analysis and design of pulse frequency modulation dielectric barrier discharge for low power applications

Tang-tang GUO,Xing-liang LIU,Shi-qiang HAO,Chi ZHANG,Xiang-ning HE

《信息与电子工程前沿(英文)》 2015年 第16卷 第3期   页码 249-258 doi: 10.1631/FITEE.1400185

摘要: For low power dielectric barrier discharge (DBD) used in small-size material treatment or portable devices, highstep transformer parasitic capacitance greatly influences the performance of the resonant converter as it is of the same order of magnitude as the equivalent capacitance of DBD load. In this paper, steady-state analysis of the low power DBD is presented, considering the inevitable parasitic capacitance of the high-step transformer. The rectifier-compensated first harmonic approximation (RCFHA) is applied to linearize the equivalent load circuit of DBD at low frequency and the derived expressions are accurate and convenient for the analysis and design of the power supply. Based on the proposed linear equivalent load circuit, the influence of transformer parasitic capacitance on the key parameters, including the frequency range and the applied electrode voltage, is discussed when the power is regulated with pulse frequency modulation (PFM). Also, a design procedure is presented based on the derived expressions. A prototype is constructed according to the design results and the accuracy of the design is verified by experimental results.

关键词: Dielectric barrier discharge     Rectifier-compensated first harmonic approximation     Parasitic capacitance     Power converter design    

安全性第一准则下的组合贷款模型

唐万生,严维真,宁玉富

《中国工程科学》 2007年 第9卷 第11期   页码 137-141

摘要:

提出了一种在概率准则意义下的组合贷款模型,并设计了基于随机模拟的混合优化算法进行求解。 该算法突破了各种贷款收益率必须服从正态分布的假定,可对贷款收益率是任意分布形式的模型进行求解。 经数值仿真,验证了算法的可行性。

关键词: 组合贷款     安全性第一准则     随机模拟     遗传算法     同步扰动随机逼近    

过程神经元网络的若干理论问题

何新贵,梁久祯

《中国工程科学》 2000年 第2卷 第12期   页码 40-44

摘要:

文章提出一种过程神经元模型,其输人为与时间有关的函数或过程,它是传统人工神经元模型在时间域上的扩展。基于这种过程神经元模型,给出了一种仅含一个隐层的前馈型过程神经网络模型,即基展开过程神经元网络模型。证明了相应的连续性定理,逼近定理,计算能力定理等。

关键词: 过程神经元网络     函数逼近能力     计算能力     连续性    

标题 作者 时间 类型 操作

A case study on sample average approximation method for stochastic supply chain network design problem

Yuan WANG, Ruyan SHOU, Loo Hay LEE, Ek Peng CHEW

期刊论文

Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

期刊论文

广义近似空间与粗糙分类代数

刘永红

期刊论文

连续非线性最优控制问题的勒让德—伽辽金逼近方法

Xue-song CHEN

期刊论文

满足MapReduce环境下近似处理的时限要求

Ming-hao HU, Chang-jian WANG, Yu-xing PENG

期刊论文

Approximation of structural damping and input excitation force

Mohammad SALAVATI

期刊论文

复杂地质曲面三维插值—逼近拟合构造方法

李明超,缪正建,刘菲,王刚

期刊论文

Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

期刊论文

Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

期刊论文

Shape design of arch dams under load uncertainties with robust optimization

Fengjie TAN, Tom LAHMER

期刊论文

Nonlinear dynamics of a wind turbine tower

A. GESUALDO, A. IANNUZZO, F. PENTA, M. MONACO

期刊论文

任意隶属度函数模糊系统的逼近特性

张钊,裴燕玲,郑爱红

期刊论文

Analysis and design of pulse frequency modulation dielectric barrier discharge for low power applications

Tang-tang GUO,Xing-liang LIU,Shi-qiang HAO,Chi ZHANG,Xiang-ning HE

期刊论文

安全性第一准则下的组合贷款模型

唐万生,严维真,宁玉富

期刊论文

过程神经元网络的若干理论问题

何新贵,梁久祯

期刊论文