永恒与改建——武汉美术馆浅析

本文通过对武汉美术馆历史因素和地理状况、平面布局、立面造型、技术措施四个方面的分析,探讨了历史建筑在改扩建过程中如何平衡更新和保护之间的关系。     

Finite-time fault tolerant attitude stabilization control for rigid spacecraft

A sliding mode based finite-time control scheme is presented to address the problem of attitude stabilization for rigid spacecraft in the presence of actuator fault and external disturbances. More specifically, a nonlinear observer is first proposed to reconstruct the amplitude of actuator faults and external disturbances. It is proved that precise reconstruction with zero observer error is achieved in finite time. Then, together with the system states, the reconstructed information is used to synthesize a nonsingular terminal sliding mode attitude controller. The attitude and the angular velocity are asymptotically governed to zero with finite-time convergence. A numerical example is presented to demonstrate the effectiveness of the proposed scheme.     

曲面重构模型精度分析研究

运用Geomagic Qulify软件,以测量点到曲面模型的距离为主要评价指标,对用传统曲面造型方式和快速曲面造型方式重构的鞋楦曲面分别进行质量评价,通过模型的3D比较、2D比较及特殊点的比较,得到模型的3D偏差图、误差分布百分比图表、截面标准偏差图和截面百分比偏差图,通过分析比较图表,可知两种曲面重构方式所得曲面均符合要求,可根据曲面重构质量的不同要求选择恰当的曲面重构方式,为其他模型的曲面测评和曲面重构方式的选择提供了参考依据。     

汽车覆盖件曲面重构技术研究

针对目前专用逆向工程设计软件提供的工具及面的质量不如正向软件,正向软件读取海量点云数据速度慢的问题,提出了一种将Geomagic和CATIA相结合的机械零件逆向建模方法。以某车型发动机盖的逆向设计为研究对象,利用ATOS&TriTop系统采集点云数据,逆向工程软件Geomagic进行点云数据处理,正向工程软件CATIA进行零件曲面造型,并针对重构后的曲面进行了精度与光顺性检测。研究表明,充分结合两大软件的优势,能有效的提高产品设计的速度与质量,进而缩短产品的研发周期,增强企业竞争力。     

中国传统建筑装修文化之创新思维

该文着重探讨了中国传统建筑装修文化的当代创新思维，即基于象征和隐喻上的联想创新思维、基于多元文化要素上的移植创新思维、基于建筑装修本体上的理性创新思维、基于类型上的重构创新思维。并深究其在当代中国得以滋生的土壤基础、具体表现及其优缺成分。     

形态重塑——哈根岛住宅"类型-结构"设计策略解析

该文通过对荷兰勇堡哈根岛住宅设计图示分析,展现了设计者将设计意图转化为结果所采用的"类型-结构"策略.同时针对群体建筑集合建造活动,讨论了这种设计策略基于形态重塑"过程"基本目标的现实意义.     

融合与重构——宁德会展中心扩建工程的运作与启示

本文通过对宁德会展中心的扩建项目,在原有建筑设计的限制下,提炼、融合、重构宁德地域文化的内涵与场所文脉。进而初步探讨,大中型展览建筑的整体设计,应基于当地文脉和自然人文环境特征基础之上。总结出设计应尊重场所文脉、遵循文化尺度、体现整体特色。     

Reconstruction of 3D objects from 2D cross-sections with the 4-point subdivision scheme adapted to sets

Reconstruction of 3D objects from 2D cross-sections is an intriguing problem with many potential applications. We approach this problem through a novel multi-resolution method based on iterative refinement of the sets representing the cross-sections. To that end, we introduce a new geometric weighted average of two sets, defined for positive weights (corresponding to interpolation) and when one weight is negative (corresponding to extrapolation). This new average can be used to interpolate between cross-sections of a 3D object in a piecewise way. To obtain a smoother reconstruction of the 3D object, we adapt to sets the 4-point interpolatory subdivision scheme using the new average with both positive and negative weights. The effectiveness of the new method is demonstrated by several examples.     

Optimization study on the reconstruction and expansion of an underground rail transit center in Shanghai soft ground

To meet the demand of rapid growing passenger flow, Shanghai-Century-Avenue-Transit-Center (SCATC) was reconstructed to integrate two new metro stations with the existing ones. The entire reconstruction process of SCATC involved a cluster of complicated construction cases and procedures including dismantling and restructuring of old station structures as well as deep excavations. In order to control the disturbance of the reconstruction to a minimum, a series of numerical simulations coupling with system control conceptions were conducted for optimizing the reconstruction process. All the involved major cases and their included procedures had been identified and thoroughly investigated to ensure that the incremental effect of each step and overall impact on the old or remaining stations were all within the control criterion for metro operation. The primary findings obtained were: (1) An approach of coupling system control conceptions with numerical simulations incorporated updating procedures was conducted to determine the optimal sequence for the reconstruction, and proved to be efficient and pragmatic; (2) A robust anti-upheaval system was applied and proved very effective in reducing the upheaval effects induced by dismantling structures. With the help of the anti-upheaval system, the displacements induced by subsequent actions had also been reduced much more than expected; (3) In the cutting-hole procedure on walls, by setting the hole size of per-cutting within 1 m and the hole-spacing of no less than 4 m with compensating measures for concentrated forces, the potential damages to the station structures had been prevented effectively; (4) By dividing the large pit into small independent pits with compartment walls, excavating each individual pit and forming its inside structures separately before the adjacent pit started, the rail displacement induced by the large pit excavation had been controlled within 10 mm in Shanghai soft ground; (5) The optimal overall sequence for the SCATC reconstruction was determined by investigating and comparing the effects of all construction paths defined by permutation of the major cases. The optimal sequence was executed and proved successful by the field measurements and observations.     

采用多点地质统计法重构页岩的数字岩心

由于实验设备获得的页岩岩样大多是微米或毫米尺度,如果要获得更大尺度和范围内的孔隙结构,必须通过对其特征的三维重构才能实现。为此,提出了基于纳米精度的体数据与多点地质统计方法的页岩三维数字岩心重构方法。以页岩纳米CT数据为训练图像,使用数据模板提取其中的结构特征,通过多点地质统计方法将结构特征重构到数字岩心中;形成了以变差函数曲线、孔隙直径分布和孔隙连通性来判别重构岩心与真实页岩结构相似度的判别方法 ;基于格子玻尔兹曼方法验证了相似度评价方法。结果表明:(1)变差函数可以检验重构岩心与真实岩心的空间相似性,孔隙直径分布和孔隙连通性可以检验流动特征的相似性;(2)当变差函数曲线、孔隙直径分布和孔隙连通性相似时,重构岩心与真实岩心的渗透率相近,表明所提出的重构方法与结构相似度评价方法是有效的;(3)由于强非均质性,不同位置的重构页岩岩心渗透率差异可超过100倍。该研究成果对构建三维大尺寸强非均质性页岩数字岩心、认识页岩孔隙结构、分析流动规律具有指导作用。