Decentralized Stabilization of Large-scale Uncertain Systems with State-Delays——LMIs Approach

This paper deals with the problem of decentralized robustcontrol for a class of interconnected uncertain systemswith state delays.The parameter uncertainties are un-known but norm-bounded.A new sufficient condition isobtained for each subsystem and overall system to be sta-bilizable via linear memoryless state feedback robust de-centralized controllers.The results depend on the size of the delays and are given in terms of linear matrix ine-qualities,so they are less conservative than those of delay-independent.Moreover,matching condition is not a necessary condition.Finally,an example is presented to illustrative the effectiveness of the proposed method.

考虑最小尺寸控制的压力驱动柔顺机构拓扑优化设计

拓扑优化设计的压力驱动柔顺机构拓扑构型容易出现类铰链结构,导致难以制造加工。为了满足制造工艺要求,提出一种考虑最小尺寸控制的压力驱动柔顺机构拓扑优化设计方法。采用改进的固体各向同性材料惩罚模型,利用达西定律结合排水项计算流体压力载荷,以机构的互应变能最大化和应变能最小化为优化目标,采用Otsu算法和拓扑细化算法提取柔顺机构的骨架特征,从而构建最小特征尺寸控制,以结构体积和最小特征尺寸作为约束,建立考虑最小尺寸控制的压力驱动柔顺机构拓扑优化模型,采用移动渐近线算法进行压力驱动柔顺机构拓扑优化问题求解。数值算例结果表明,所提设计方法获得的压力驱动柔顺机构最小特征尺寸满足约束,能够有效地抑制类铰链结构,并且分析不同最小控制尺寸对柔顺机构拓扑优化结果影响规律。

面向大规模数据属性效应控制的核心向量回归机

属性效应在现实生活中广泛存在,如果不加以控制,将会严重影响回归学习的性能.针对大规模数据属性效应控制的非线性回归学习问题,提出了快速等均值核心向量回归机(fast equal mean-core vector regression,FEM-CVR).首先基于间隔最大化目标学习准则,通过施加等均值约束条件,提出了等均值支持向量回归机(equal mean-support vector regression,EM-SVR).在此基础上,证明了EMSVR等价于一个中心约束最小包含球(center constrained-minimum enclosing ball,CC-MEB)问题,然后通过引入近似最小包含球理论,得到原始输入数据集的压缩集即核心集(core set),进一步提出了针对大规模数据属性效应控制的最小包含球快速非线性回归学习方法 FEM-CVR,并从理论上对相关性质进行了深入分析.实验表明:该方法能够快速处理针对大规模数据属性效应控制的非线性回归学习问题,具有较好的泛化能力,并且其时间复杂度上限与数据集大小无关,仅与最小包含球近似参数ε-有关.

考虑混合约束的柔顺机构拓扑优化设计

为了满足制造工艺和静强度要求,提出一种综合考虑最小尺寸控制和应力约束的柔顺机构混合约束拓扑优化设计方法。采用改进的固体各向同性材料插值模型描述材料分布,利用多相映射方法同时控制实相和空相材料结构的最小尺寸,采用最大近似函数P范数求解机构的最大应力,以机构的输出位移最大化作为目标函数,综合考虑最小特征尺寸控制和应力约束建立柔顺机构混合约束拓扑优化数学模型,利用移动渐近算法求解柔顺机构混合约束拓扑优化问题。数值算例结果表明,混合约束拓扑优化获得的柔顺机构能够同时满足最小尺寸制造约束和静强度要求,机构的von Mises等效应力分布更加均匀。

AN ADAPTIVE CONTROL STRATEGY FOR PROPER MESH DISTRI-BUTION IN LARGE EDDY SIMULATION

The Filtering Grid Scale （FGS） of sub-grid scale models does not match with the theoretical Proper FGS （PFGS） because of the improper mesh. Therefore, proper Large Eddy Simulation （LES） Mesh is very decisive for better results and more economical cost. In this work, the purpose is to provide an adaptive control strategy for proper LES mesh with turbulence theory and CFD methods. A new expression of PFGS is proposed on the basis of -5/3 law of inertial sub-range and the proper mesh of LES can be built directly from the adjustment of RANS mesh. A benchmark of the backward facing step flow at Re = 5147 is provided for application and verification. There are three kinds of mesh sizes, including the RANS mesh, LAM （LES of adaptive-control mesh）, LFM （LES of fine mesh）, employed here. The grid number of LAM is smaller than those of LFM evidently, and the results of LAM are in a good agreement with those of DNS and experiments. It is revealed that the results of LAM are very close to those of LFM. The conclusions provide positive evidences for the novel strategy.

城市住宅区用地规模控制研究——以济南市为例

在分析住宅区用地规模控制根源的基础上,提出了尊重各个利益主体价值取向的用地规模控制思路,并从物业管理的经济性、公建规模的合理性、绿地系统的功能性、居住空间的多样性和城市更新的整体性等方面探讨了住宅区用地最小规模控制的依据。