LBS中基于轨迹的用户行为特征分析     

陈典全 《全球定位系统》2011,36(6):58-61,79

LBS的发展趋势是向用户提供智能化、个性化的位置服务。以用户行为轨迹数据为基础,进行轨迹简化、POI匹配、时空融合、习惯分析等处理,建立起用户行为特征模型,从而实现向不同用户提供个性化位置服务。  相似文献   

基于文献统计的地理信息共享研究视角分析     

余旭 《测绘科学》2011,36(3):59-61

地理信息共享是近年来地理信息系统领域的研究热点之一.自地理信息共享环境的概念提出以来,许多学者从不同的视角对地理信息共享进行了研究和论述.论文用文献计量学的方法,从研究视角的角度,对国内外的同地理信息共享相关的文献进行了定量分析,对地理信息共享的研究视角进行了评述,分析了当前的研究视角存在的一些问题.定量分析的结果还表...  相似文献   

Reduced‐dimension nonlinear finite‐element analysis of a vibrating disk in an unbounded domain     

Punchet Thammarak  John L. Tassoulas 《地震工程与结构动力学》2011,40(12):1353-1366

We present and evaluate the formulation of a reduced‐dimension (one‐dimensional) finite element for the nonlinear analysis of a vibrating disk in a two‐dimensional unbounded domain. As this problem is relevant in studies of the dynamic response of laterally loaded piles, numerous spring‐and‐dashpot representations of the disk undergoing displacement in an unbounded material domain have been developed to date: static and dynamic, linear and nonlinear. With the focus on material nonlinearity, the present simplified formulation circumvents the complications associated with nonlinear springs and dashpots. Indeed, the continuum‐based treatment described herein accounts for the interaction between the two modes of energy dissipation, due to wave propagation in the unbounded domain and loss associated with inelastic behavior. The formulation is a good compromise between the competing desires for realistic representation and efficient computation. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

钢管混凝土边框内藏钢板剪力墙振动台试验研究   总被引：2，自引：1，他引：1  

曹万林  王尧鸿  董宏英  张建伟 《地震工程与工程振动》2011,31(2):75-81

进行了4个钢板剪力墙模型的模拟地震振动台试验,其中2个模型为钢管混凝土边框钢板剪力墙,高宽比分别为1.7和3.2;2个模型为钢管混凝土边框内藏钢板剪力墙,高宽比分别为1.7和3.2.试验中输人Taft地震动,测试了各试件在不同峰值加速度下的时程地震反应和动力特性,分析了剪力墙的破坏特征.研究表明:钢管混凝土边框内藏钢板...  相似文献   

双塔连体结构弹塑性时程分析   总被引：1，自引：0，他引：1  

吴晓涵  韦晓栋  钱江  吕西林 《地震工程与工程振动》2011,31(3):51-58

双塔连体结构是我国实际工程中应用越来越多的一种结构形式.该结构形式是在两塔楼顶部设置连体部分的新型建筑结构形式.本文针对某一连体结构,采用NosaCAD有限元软件建立整体结构分析模型.通过建立模型,分析结构在7度多遇和罕遇地震下的弹塑性时程反应,得到结构在地震作用下的变形、内力和破坏情况的变化过程.结果表明,小震情况下...  相似文献   

Experimental research on the seismic behavior of CSPSWs connected to frame beams     

Guo Lanhui  Ma Xinbo  Li Ran§  Zhang Sumei* School of Civil Engineering  Harbin Institute of Technology  Harbin  China 《地震工程与工程振动(英文版)》2011,10(1):65-73

The seismic performance of composite steel plate shear walls (CSPSWs) that consist of a steel plate shear wall (SPSW) with reinforced concrete (RC) panels attached to one or both sides by means of bolts or connectors is experimentally studied. The shear wall is connected to the frame beams but not to the columns. This arrangement restrains the possible out-of-plane buckling of the thin-walled steel plate, thus significantly increasing the bearing capacity and ductility of the overall wall, and prevents the premature overall or local buckling failure of the frame columns. From a practical viewpoint, these solutions can provide open space in a floor as this type of composite shear walls with a relatively small aspect ratio can be placed parallel along a bay. In this study, four CSPSWs and one SPSW were tested and the results showed that both CSPSWs and SPSW possessed good ductility. For SPSW alone, the buckling appeared and resulted in a decrease of bearing capacity and energy dissipation capacity. In addition, welding stiffeners at corners were shown to be an effective way to increase the energy dissipation capacity of CSPSWs.  相似文献   

钻孔灌注桩泥浆流变特性及水力参数研究分析     

郑秀华 《地质与勘探》2013,49(5):958-963

钻孔灌注桩泥浆主要功能是稳定孔壁、悬浮和携带钻渣,其泥浆流变特性和水力参数对泥浆作用至关重要。本文首先实验研究了钻孔灌注桩泥浆的流变特性;然后推导出了钻孔灌注桩泥浆流变参数的计算公式;最后分析了钻孔灌注桩泥浆稳定孔壁、携带和悬浮钻渣的特性,对评价和优化钻孔灌注桩泥浆具有重要理论和实践意义。  相似文献   

试论中国旅游地域类型的演进模式   总被引：8，自引：2，他引：8  

范今朝 《地理研究》2000,19(1):22-29

从旅游地理学和历史地理学的角度,研究了中国旅游这一宏观社会历史现象。以旅游活动中人地关系的演变为中心,首先按照影响旅游活动的主导因素及其价值取向的不同,对中国旅游发展进行了历史分期;相应地,提出了中国旅游地域类型的演进模式,即:经商求知阶段——都市旅行型;崇拜事功阶段——朝圣巡礼型;审美抒情阶段——风景观光型;艺术把玩阶段——园林游赏型;外部植入阶段——消闲娱乐型;政府主导阶段——疗养休憩型;市场推进阶段——度假运动型;自主选择阶段——生态探险型。  相似文献   

Autotomy in porcelain crabs is an effective escape mechanism from rockfish predation     

Matthew L. Knope  Ralph J. Larson 《Marine Ecology》2014,35(4):471-477

Porcelain crabs possess a ‘hair‐trigger’ propensity to autotomize their chelipeds (claws), and laboratory studies have demonstrated that this ability is highly effective in avoiding predation from other crabs. However, porcelain crabs are also subject to predation from fishes, which use a very different means of capture. In this study, we investigated whether autotomy in porcelain crabs is also effective against predation by fishes. To do this, we examined stomach‐contents data from four common species of kelp‐forest rockfishes and determined the frequency of disassociated chelipeds (those with no associated bodies) in porcelain crabs and in brachyuran crabs, which do not readily autotomize their chelipeds. We found that disassociated chelipeds of porcelain crabs were six times as common as those of brachyuran crabs (35% of the remains of all porcelain crabs versus 6% of the remains of all brachyuran crabs). We interpret this difference to be evidence that, through autotomy, porcelain crabs escaped ingestion of their entire bodies, and thus certain mortality, at a higher rate than did brachyuran crabs. We conclude that autotomy constituted an effective escape strategy from rockfish predation. This evidence, in conjunction with previous studies, suggests that autotomy of chelipeds in porcelain crabs is an effective anti‐predatory strategy against phylogenetically disparate predatory groups.  相似文献   

长江口及其邻近海域溶解硒的地球化学控制过程研究     

吴晓丹  宋金明  吴斌  李铁刚  李学刚 《海洋学报(英文版)》2014,33(10):19-29

Dissolved selenium in the Changjiang(Yangtze) Estuary and its adjacent waters was determined by hydride generation atomic fluorescence spectrometry to elucidate the source, behavior in estuary, adsorption-desorption process and biological role. In surface water, Se(IV) concentration ranged 0.05–1.14 nmol/L and Se(VI) concentration varied 0.01–1.20 nmol/L, with the means of 0.76 and 0.49 nmol/L, respectively. In bottom water, Se(IV) content varied 0.03–0.27 nmol/L and Se(VI) content ranged 0.04–0.85 nmol/L, with the averages of 0.10 and 0.40 nmol/L, respectively. High level of Se(IV) was observed near the shore with a significant decrease towards the open sea, suggesting the continental input from the adjacent rivers. Large value of Se(VI) was found in bottom water, reflecting the release from suspended sediment. Besides, high value appeared in the same latitude of the Changjiang Estuary and Hangzhou Bay illustrated the effect of lateral mixing and the long-distance transport of selenium. Se(VI), more soluble, occupied higher percentage in aqueous environment. The presence of Se(IV) resulted from the degradation of residue and the reduction of Se(VI) under anaerobic condition. The positive relationship to suspended particulate material(SPM) and negative correlation to depth indicated that Se(IV) tended to be released from the high density particulate matter. Instead, Se(VI) content did not significantly relate to SPM since it generally formed inner-sphere complex to iron hydroxide. Se(IV) content negatively varied to salinity and largely depended on the freshwater dilution and physical mixing. While, Se(VI) level deviated from the dilution line due to the in situ biogeochemical process such as removal via phytoplankton uptake and inputs via organic matter regeneration. As the essential element, Se(IV) was confirmed more bioavailable to phytoplankton growth than Se(VI), and moreover, seemed to be more related to phosphorus than to nitrogen.  相似文献