Measures of transport mode segmentation of trajectories     

Adrian C. Prelipcean  Gyözö Gidofalvi  Yusak O. Susilo 《International journal of geographical information science》2016,30(9):1763-1784

ABSTRACT

Rooted in the philosophy of point- and segment-based approaches for transportation mode segmentation of trajectories, the measures that researchers have adopted to evaluate the quality of the results (1) are incomparable across approaches, hence slowing the progress in the field and (2) do not provide insight about the quality of the continuous transportation mode segmentation. To address these problems, this paper proposes new error measures that can be applied to measure how well a continuous transportation mode segmentation model performs. The error measures introduced are based on aligning multiple inferred continuous intervals to ground truth intervals, and measure the cardinality of the alignment and the spatial and temporal discrepancy between the corresponding aligned segments. The utility of this new way of computing errors is shown by evaluating the segmentation of three generic transportation mode segmentation approaches (implicit, explicit–holistic, and explicit–consensus-based transport mode segmentation), which can be implemented in a thick client architecture. Empirical evaluations on a large real-word data set reveal the superiority of explicit–consensus-based transport mode segmentation, which can be attributed to the explicit modeling of segments and transitions, which allows for a meaningful decomposition of the complex learning task.  相似文献   

Long-term and regional variability of phytoplankton biomass in the Northeast Atlantic (1960-1995)   总被引：2，自引：0，他引：2  

Edwards  Martin; Reid  Philip; Planque  Benjamin 《ICES Journal of Marine Science》2001,58(1):39-49

  相似文献   

系缆式水下自动升降平台   总被引：4，自引：1，他引：4  

商红梅 《海洋技术学报》2005,24(1):19-20,24

系缆式自动升降平台应用到水下定点测量系统中，可以用一套观测仪器完成全剖面的测量，和以往锚系系统单点分层测量方式相比，它具有连续进行剖面测量的先进性和经济性。文章介绍了系缆式水下自动升降平台的应用方式、升降原理、结构组成以及原理样机在实验室和千岛湖进行试验的情况。  相似文献   

Plankton Distribution Patterns in a Mediterranean Dilution Basin: Amvrakikos Gulf (Ionian Sea, Greece)     

P. Panayotidis    M. A. Pancucci    E. Balopoulos  O. Gotsis-Skretas   《Marine Ecology》1994,15(2):93-104

Abstract. The present work describes Amvrakikos Gulf (Ionian Sea, Greece) as a dilution basin and provides information concerning the relationships between the hydrology and plankton composition and distribution.
Amvrakikos Gulf is characterized by a differentiated planktonic system which is apparently directly influenced by the input of the rivers located at the northern part of the gulf.  相似文献   

遥墙机场环境噪声影响预评价     

卫孝泉  李江吉  许龙江  孙晓光 《中国海洋大学学报(自然科学版)》1994,(1)

采用有效感觉噪声级Ｌｅｐｎ作为单个事件的评价量，用计权等效连续感觉噪声级Ｌｗｅｃｐｎ作为一段时间内多个事件的评价量，介绍了机场环境噪声影响预测的完整程序和方法。给出了遥墙机场１９９５年度的预测结果。  相似文献   

浮游生态系统非线性动力学研究     

冯剑丰  李会民  王洪礼 《海洋技术学报》2007,26(3):67-69

建立了新的藻类-浮游动物生态非线性动力学模型,该模型考虑了藻类与浮游动物之间的增长关系。研究了模型平衡点的稳定性,以及Hop f分岔现象。通过对选取的分岔参数进行分析,揭示了该系统的动力学特性。  相似文献   

张家口地震台连续重力异常分析     

屈曼  侯晓真  陈建国  王曰风  朱振兴  周亚  刘仲韬 《山西地震》2021,(1):26-29,49

张家口地震台gPhone连续重力观测仪潮汐因子自2016年6月出现持续下降的趋势变化,累计变化量达到7×10-3。分析重力残差曲线,异常出现时同期残差数据未出现同步变化;将去零漂前后潮汐因子的变化情况进行对比分析,发现潮汐因子变化趋势一致,排除仪器调零影响;针对新建楼房可能引起的重力变化,建立了重力正演模型,计算结果显示,新建楼房的荷载变化仅能引起0.31微伽的重力变化,表明新建楼房对重力观测的影响较弱。综合分析认为,此次出现的重力潮汐因子下降趋势异常可能为前兆异常,需加强跟踪分析。  相似文献   

Cluster synchronisation: A mechanism for plankton patchiness and a simulation pitfall     

Emma Guirey  Adrian Martin  Meric Srokosz  Martin Bees   《Ocean Modelling》2009,29(4):223-233

We present a study on the emergence of spatial variability, or patchiness, in biophysical simulations of plankton ecosystems. Using a standard approach to modelling such ecosystems, we represent a distribution of plankton as a lattice of non-identical interacting oscillatory populations. Spatial variation is imposed in population parameters, such as maximum growth rate, leading to a spread in the natural (uncoupled) population properties. Using the methods of synchronisation theory, the emergent spatial structure of the coupled system is investigated as a function of the strength of interaction between populations. Surprisingly, a range of coupling strength is found to induce a tenfold increase in the spread in frequency of oscillation of populations in comparison with the uncoupled level of spatial variation. This apparent desynchronisation corresponds to the formation of temporally evolving clusters of local synchronisation: the interplay of grid-cell scale variability and dispersal between populations leads to patchiness at larger scales. However, the occurrence and length-scale of this patchiness is found to be sensitive to typical simulation parameters such as spatial resolution and strength of dispersal, with emergent spatial structure altering abruptly from patchy to homogeneous as these parameters are varied. These results indicate that whilst cluster synchronisation may be a genuine mechanism for the formation of spatial structure in plankton distributions, biophysical modellers should be aware of the possibility of artificial patchiness arising from the basic physical structure of their model.  相似文献   

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梅生强  宫煦利  姚宜斌  王泽民  黄石磊 《大地测量与地球动力学》2008,28(1):131-135

???????вο???(CORS)????????????GPS???????????λ(RTK)??????????GPS??????λ?????????????? ??λ???????????????????????????????????????????е?Delaunay?????????????????????CORS????????????????????????????????????????????????ο??????????????????????????????????????????Ч???????????  相似文献   

2000年7月中旬河南连续性暴雨过程分析     

张一平 《河南气象》2001,(4):22-24

利用2000年7月12－16日逐时雨量、逐时风场、探空及多普勒雷达回波资料，分析了2000年7月12－16日河南连续性暴雨的雷达回波特征及中尺度系统活动与暴雨的对应关系，揭示中尺度系统是造成暴雨的直接原因。  相似文献