Structural physical parameter identification based on evolutionary-simplex algorithm and structural dynamic response

Evolutionary computation based on the idea of biologic evolution is one type of global optimization algorithm that uses self-adaptation, self-organization and random searching to solve optimization problems. The evolutionary-simplex algorithm is introduced in this paper. It contains floating encoding which combines the evolutionary computation and the simplex algorithm to ovcrcomc the problems encountered in the genetic algorithm and evolutionary strategy methods.Numerical cxpcrimcnts arc performed using seven typical functions to verify the algorithm. An inverse analysis method to identify structural physical parameters based on incomplete dynamic responses obtained from the analysis in the time domain is prcscntcd by using the evolutionary-simplex algorithm. The modal evolutionary-simplex algorithm converted from the time domain to the modal domain is proposed to improve the inverse efficiency. Numerical calculations for a 50-DOF system show that whcn compared with other methods, the evolutionary-simplex algorithm offers advantages of high precision,cfficient searching ability, strong ability to resist noise, independence of initial value, and good adaptation to incomplete information conditions.     

文化身份视角下移民城市的城中村更新模式探讨——基于新加坡与深圳的实证研究

选取新加坡和深圳的3个城中村作为实证研究对象,从文化身份的理论视角切入,剖析移民城市的城中村更新的文化塑造过程;指出要理解文化身份的内涵与本质,需要理解地方蕴含的全球性与在地性、过去与现在这两组关系。在解读宏观文化政策的内在政治和经济推动力的基础上,基于参与式观察和半结构化访谈资料,运用质性分析方法,比较探讨典型移民城市城中村的更新模式、政策机制及社会影响。结果发现,2座城市在对待文化身份尤其是移民文化的态度不同,产生了不同的更新效果。新加坡案例以实际生活在此的移民群体的生活方式为出发点塑造地方特色,并提供公屋政策支持,因而能够在发展展示经济的同时保有社区的延续性。深圳案例则是人为选择和指定某个历史时期的建筑风格作为特色加以强调,发展文化旅游经济,这种方式塑造的文化身份与原有社区和住民的关系不大,最终导致地区的高档化,使得大部分移民群体被驱逐、社会关系网络断裂。研究认为,文化身份的选定本质上是对文化资本的使用,代表的是城中村更新主导方的价值取向。而身份认同在文化语境中的话语权,代表了群体对城市空间的社会权利。因此,文化导向的城中村更新应从当地社区居民的角度出发,关注其长期积淀的社会关系和特定人群需求,而非物质空间的表面意向,才能实现更为公正、包容且可持续的城市复兴。