本文介绍了基于工业基础类IFC(Industry Foundation Class)的协同设计标准研究。初步研究指出:作为建筑行业中协同设计数据标准应该是开放的标准,IFC是满足该要求的建筑行业数据标准。进一步的研究实践表明,IFC数据格式标准只是协同设...本文介绍了基于工业基础类IFC(Industry Foundation Class)的协同设计标准研究。初步研究指出:作为建筑行业中协同设计数据标准应该是开放的标准,IFC是满足该要求的建筑行业数据标准。进一步的研究实践表明,IFC数据格式标准只是协同设计的必要条件,但不是充要条件。设计中各专业之间信息交互的流程也必须要明确定义,否则作为建筑信息模型的通用数据结构IFC格式无法保证专业之间信息交互的正确性和高效性。本文介绍了基于"用例"(use case)分析的方法——信息提交手册IDM(Information Delivery Manual),来定义设计工作流程的信息交互标准,以及在IDM基础上的计算机软件实现的模型视图定义MVD(Model ViewDefinition)。本文指出,基于IFC的协同设计标准框架应该包括三个层次,即IFC数据结构、信息提交手册,以及模型视图定义。展开更多
Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed vi...Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed video with interframe motion vectors for speed, density and flow detection, has been proposed for ex-traction of traffic information under fixed camera setting and well-defined environment. The motion vectors arefirst separated from the compressed video streams, and then filtered to eliminate incorrect and noisy vectors u-sing the well-defined environmental knowledge. By applying the projective transform and using the filtered mo-tion vectors, speed can be calculated from motion vector statistics, density can be estimated using the motionvector occupancy, and flow can be detected using the combination of speed and density. The embodiment of aprototype system for sky camera traffic monitoring using the MPEG video has been implemented, and experi-mental results proved the effectiveness of the method proposed.展开更多
The goal of Optoelectronics Letters is to rapidly report original, new and important results in the fields of photonics and optoelec- tronics in English, to advance the international academic exchanges. Optoelectronic...The goal of Optoelectronics Letters is to rapidly report original, new and important results in the fields of photonics and optoelec- tronics in English, to advance the international academic exchanges. Optoelectronics Letters pays a particularly attention to the cross topics between photonics and electronics.展开更多
文摘Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed video with interframe motion vectors for speed, density and flow detection, has been proposed for ex-traction of traffic information under fixed camera setting and well-defined environment. The motion vectors arefirst separated from the compressed video streams, and then filtered to eliminate incorrect and noisy vectors u-sing the well-defined environmental knowledge. By applying the projective transform and using the filtered mo-tion vectors, speed can be calculated from motion vector statistics, density can be estimated using the motionvector occupancy, and flow can be detected using the combination of speed and density. The embodiment of aprototype system for sky camera traffic monitoring using the MPEG video has been implemented, and experi-mental results proved the effectiveness of the method proposed.
文摘The goal of Optoelectronics Letters is to rapidly report original, new and important results in the fields of photonics and optoelec- tronics in English, to advance the international academic exchanges. Optoelectronics Letters pays a particularly attention to the cross topics between photonics and electronics.
