当今,使用手机网页来访问大规模建筑环境逐渐被人们所追求.BIM(building information modeling)是新一代智能建造的核心技术.本文以其主流格式IFC(industry foundation classes)作为输入数据格式,提出一套面向手机网页的大规模Web BIM...当今,使用手机网页来访问大规模建筑环境逐渐被人们所追求.BIM(building information modeling)是新一代智能建造的核心技术.本文以其主流格式IFC(industry foundation classes)作为输入数据格式,提出一套面向手机网页的大规模Web BIM场景实时漫游算法.与图形学领域的可视化程序相比,该方法不只注重可视化渲染时的面片级处理,更是在遵从建筑语义的前提下,以建筑构件为单位,对大规模Web BIM场景进行轻量化处理.方法主要从构件实例冗余、构件及空间混合索引、多粒度数据动态装/卸载策略3方面对场景数据量、组织结构、动态数据管理进行优化,并集成到原型系统.实验表明本文方法的去冗比例达70%左右,原型系统的FPS能保持在30左右,内存损耗约400 MB,能较稳定、流畅地在手机网页上进行大规模Web BIM场景的实时漫游.展开更多
The significance,description parameters,evaluation method,implement way and design for lightweight of automobile are comprehensively reviewed.The relationship among the performances of auto parts & components,the ...The significance,description parameters,evaluation method,implement way and design for lightweight of automobile are comprehensively reviewed.The relationship among the performances of auto parts & components,the properties of materials and application of advanced technologies is also elaborated.According to recently related progress of lightweight and authors' research and developing work,lightweight of automobile is comprehensively and systematically overviewed.展开更多
The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship betw...The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.展开更多
Lightweight is an effective design strategy to conserve energy in automotive vehicles.It is a big challenge to evaluate the level of lightweight for passenger cars.This paper summarizes various evaluation methods for ...Lightweight is an effective design strategy to conserve energy in automotive vehicles.It is a big challenge to evaluate the level of lightweight for passenger cars.This paper summarizes various evaluation methods for lightweight automotive vehicles.A lightweight index[Lv for internal combustion engine vehicles(ICEVs)and Lev for battery electric vehicles(BEVs)]is proposed to assess the lightweight of passenger cars.The proposed lightweight index is composed of the nominal density,weight-to-power ratio,and fuel consumption of footprint area(in the case of ICEVs)or electricity consumption of footprint area(in the case of BEVs).The validity and universality of the proposed lightweight index are demonstrated through a statis-tical analysis of 7018 ICEV and 326 BEV models.The calculation procedures of the standard partial regression coefficients of statistical multiple regression and elastic coefficients are employed in the proposed method.The results show that either Lv or Lev is most sensitive to the curb mass of the vehicles.The proposed lightweight index can help guide automakers in setting reasonable weight reduction targets during new product development.In addition,the proposed lightweight index can be applied to new hybrid electric vehicles with further efforts,to facilitate the development of lightweight automotive design.展开更多
本文针对城市信息模型(City Information Modeling,CIM)快速构建与城市级海量三维数据渲染调度需求,深入研究了轻量化CIM构建核心技术环节,从CIM快速构建、模型轻量化和三维立体空间索引3方面提出了解决方案。最后以某地级市场景为例,...本文针对城市信息模型(City Information Modeling,CIM)快速构建与城市级海量三维数据渲染调度需求,深入研究了轻量化CIM构建核心技术环节,从CIM快速构建、模型轻量化和三维立体空间索引3方面提出了解决方案。最后以某地级市场景为例,对关键技术可行性及应用效果进行了验证。结果表明关键技术成果能够满足城市大批量三维模型快速建设以及地上地下一体化管理需求,提高了全空间模型渲染调度和查询分析效率,对于推动CIM平台建设有着重要的参考意义。展开更多
文摘当今,使用手机网页来访问大规模建筑环境逐渐被人们所追求.BIM(building information modeling)是新一代智能建造的核心技术.本文以其主流格式IFC(industry foundation classes)作为输入数据格式,提出一套面向手机网页的大规模Web BIM场景实时漫游算法.与图形学领域的可视化程序相比,该方法不只注重可视化渲染时的面片级处理,更是在遵从建筑语义的前提下,以建筑构件为单位,对大规模Web BIM场景进行轻量化处理.方法主要从构件实例冗余、构件及空间混合索引、多粒度数据动态装/卸载策略3方面对场景数据量、组织结构、动态数据管理进行优化,并集成到原型系统.实验表明本文方法的去冗比例达70%左右,原型系统的FPS能保持在30左右,内存损耗约400 MB,能较稳定、流畅地在手机网页上进行大规模Web BIM场景的实时漫游.
基金International Cooperation Project of Ministry of Science and Technology of China (No.2008DFB50020)
文摘The significance,description parameters,evaluation method,implement way and design for lightweight of automobile are comprehensively reviewed.The relationship among the performances of auto parts & components,the properties of materials and application of advanced technologies is also elaborated.According to recently related progress of lightweight and authors' research and developing work,lightweight of automobile is comprehensively and systematically overviewed.
基金Project(51078090)supported by the National Natural Science Foundation of China
文摘The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.
基金This research is funded by National Key Research and Development Program of China(Grant No.2016YFB0101605).
文摘Lightweight is an effective design strategy to conserve energy in automotive vehicles.It is a big challenge to evaluate the level of lightweight for passenger cars.This paper summarizes various evaluation methods for lightweight automotive vehicles.A lightweight index[Lv for internal combustion engine vehicles(ICEVs)and Lev for battery electric vehicles(BEVs)]is proposed to assess the lightweight of passenger cars.The proposed lightweight index is composed of the nominal density,weight-to-power ratio,and fuel consumption of footprint area(in the case of ICEVs)or electricity consumption of footprint area(in the case of BEVs).The validity and universality of the proposed lightweight index are demonstrated through a statis-tical analysis of 7018 ICEV and 326 BEV models.The calculation procedures of the standard partial regression coefficients of statistical multiple regression and elastic coefficients are employed in the proposed method.The results show that either Lv or Lev is most sensitive to the curb mass of the vehicles.The proposed lightweight index can help guide automakers in setting reasonable weight reduction targets during new product development.In addition,the proposed lightweight index can be applied to new hybrid electric vehicles with further efforts,to facilitate the development of lightweight automotive design.
文摘本文针对城市信息模型(City Information Modeling,CIM)快速构建与城市级海量三维数据渲染调度需求,深入研究了轻量化CIM构建核心技术环节,从CIM快速构建、模型轻量化和三维立体空间索引3方面提出了解决方案。最后以某地级市场景为例,对关键技术可行性及应用效果进行了验证。结果表明关键技术成果能够满足城市大批量三维模型快速建设以及地上地下一体化管理需求,提高了全空间模型渲染调度和查询分析效率,对于推动CIM平台建设有着重要的参考意义。
