虚拟层合单元与杆单元在桥梁预应力混凝土结构分析中的合成方法

对预应力混凝土的计算方法和研究现状做出了评价,提出针对预应力混凝土结构分析的单元形式。通过自由度变换,把空间杆单元的节点自由度用空间虚拟层合单元的节点自由度来表示,即杆单元的节点无需固定在体单元节点上,共同模拟了预应力混凝土结构。在单元内采用选择性积分的方法计算单元刚度矩阵,用较少的单元模拟出了复杂的断面形式;并采用单独的空间杆单元模拟预应力束,能直接求解预应力对结构产生的变形和内力。经实例验证分析,使用该单元进行预应力混凝土结构分析,在网格划分比较稀疏的情况下,仍然获得较为精确的结果,较传统的预应力计算方法更为简单、更为准确。     

高强度纤维束的动态拉伸性能

用动态拉伸装置及薄臂杆组合夹头测试了5种高强度纤维(PBO,UHMWPE,Kevlar,Glass fiber S-2,Basalt)束的动态力学性能.动态拉伸和静态拉伸结果的对比表明,5种纤维束具有应变率效应.5种纤维束的动态抗拉强度均高于静态抗拉强度,除UHMWPE外动态断裂应变均大于静态断裂应变.应变率效应对5种纤维束动态拉伸失效应变的影响无统一的规律.     

水泥混凝土路面缩缝增设传力杆施工技术

针对水泥混凝土路面设缝处极易发生病害的问题,介绍了在原未设传力杆的水泥混凝士路面增设缩缝传力杆的原理和作用,并简述了增设缩缝传力杆的必要性、可行性以及优越性;结合工程实例阐述了增设缩缝传力杆的施工技术与质量控制方法。实践证明：增设缩缝传力杆是预防和减少病害的有效措施。     

高码率Turbo码的结构及特性

构成高码率Ｔｕｒｂｏ码有删除法与多维法两种,讨论了删除法构成Ｔｏｒｂｏ码的交织器设计及删除短阵结构。通过分析两种方法构成Ｔｕｒｂｏ码的自由码距,得到了它们的误码率限,发现多维法构成的Ｔｕｒｂｏ码的性能上优于删除法构成的Ｔｕｒｂｏ码,但译码复杂度高、时延大。经比较发现,删除法构成Ｔｕｒｂｏ码能在性能与实现复杂度上取得较好折衷,是一种理论的高码率Ｔｕｒｂｏ码构成方案。     

FEMUR SHAPE RECOVERY FROM VOLUMETRIC IMAGES USING 3-D DEFORMABLE MODELS

IntroductionThe rupture of the anterior cruciate ligament( ACL) has become the most common knee in-juries.In operation of ACL reconstruction,thesurgeons have to find the optimal attachmentpoints resulting in a low anisometry of the graft,while preventing impingement between the graftand the femoral notch.Markus Fleute andStéphane lavallée[1] proposed a real- time systemfor computer- assisted ACL surgery.A recentadvance in surgery is minimally invasive tech-nique that can avoid the large…     

AN EFFECTIVE HUMAN LEG MODELING METHOD

IntroductionFFD is a widely used technique in the field ofsolid modeling and computer animation.Seder-berg and Parry introduced the conceptof FFD[1] ,and Barr provided the basic deformation methodfor FFD[2 ] .Although there are several versionsof FFD in the related literature[3～ 6 ] ,they havethe same basic idea:1 Constructa lattice space.The space can be of any shape,not restricted toparallel- piped cube[5 ] .2 Embed the object intothe lattice space.In other words,impose a localcoordi…     

AN EFFICIENT FAST ENCODING ALGORITHM FOR VECTOR QUANTIZATION

IntroductionAs an effective technique for data compression,VQ[1,2 ] has been successfully used forvarious ap-plications involving VQ- based encoding and VQ-based recognition in both vocal and image pro-cessing.The k- dimensional,N- level vectorquantizer is defined as a mapping from a k- di-mensional Euclidean space Rkinto a certain finitesubset C={Ci,i=1 ,2 ,… ,N },which is called acodebook and whose elements Ci are called code-words.A distortion measure D( X,Ci) is a non-negative dissi…     

DESIGN OF A NEW INTERPOLATED CONTROLLER FOR STABILIZATION OF A SET OF INTERPOLATED PLANTS

IntroductionDynamics of almost all plants in reality variesaccording to the condition under which the plantis operated.An idea to describe the variation ofplant dynamics is interpolating a number of rep-resentative models defined at representative op-erating points.In Ref. [1 ] ,the plant was as-sumed to described as a linear interpolation ofproper stable coprime factorizations of transferfunctions of two representative models and thestabilization problems have been considered. InRef.[2 ] ,it…     

STUDY ON CONFLICT MANAGEMENT FOR COLLABORATIVE DESIGN SYSTEM

IntroductionAdvances in computer networks and informationtechnology have enabled product designers tomore effectively communicate,collaborate,ob-tain and exchange a wide range of design re-sources during product development.ComputerSupported Cooperative Work( CSCW) describesa research area concerned with people working ingroups and computer systems supporting them,and collaborative design is an important applica-tion of CSCW.Collaborative design has typicallydistributed multiple functional…     

GLOBAL MEASURE ON IMAGE CONTENT

IntroductionContent- based image retrieval has been proposedto allow retrieval to be performed on the basis ofa variety of aspects of image content[1] .A chal-lenging problem arises with many imagedatabases,within which queries are posed via vi-sual or pictorial examples.A common visualquery to an image database system would involvefinding all images in the database which containa subimage that is similar to the query image.Such retrievals must be based on embedded con-tent features,such as sh…