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141.
GPS Solutions - The EUREF Permanent Network (EPN) is a network of continuously operating GNSS stations installed throughout the European continent. The EPN Central Bureau (CB) performs the... 相似文献
142.
When travelling, people are accustomed to taking and uploading photos on social media websites, which has led to the accumulation of huge numbers of geotagged photos. Combined with multisource information (e.g. weather, transportation, or textual information), these geotagged photos could help us in constructing user preference profiles at a high level of detail. Therefore, using these geotagged photos, we built a personalised recommendation system to provide attraction recommendations that match a user's preferences. Specifically, we retrieved a geotagged photo collection from the public API for Flickr (Flickr.com) and fetched a large amount of other contextual information to rebuild a user's travel history. We then created a model-based recommendation method with a two-stage architecture that consists of candidate generation (the matching process) and candidate ranking. In the matching process, we used a support vector machine model that was modified for multiclass classification to generate the candidate list. In addition, we used a gradient boosting regression tree to score each candidate and rerank the list. Finally, we evaluated our recommendation results with respect to accuracy and ranking ability. Compared with widely used memory-based methods, our proposed method performs significantly better in the cold-start situation and when mining ‘long-tail’ data. 相似文献
143.
144.
Grey relational analysis on the relation between marine environmental factors and oxidation-reduction potential 总被引:2,自引:0,他引:2
The effects of marine environmental factors-temperature(T),dissolved oxygen(DO),salinity(S) and pH-on the oxidation-reduction potential(ORP) of natural seawater were studied in laboratory.The results show an indistinct relationship between these four factors and the ORP,but they did impact the ORP.Common mathematical methods were not applicable for describing the relationship.Therefore,a grey relational analysis(GRA) method was developed.The degrees of correlation were calculated according to GRA and the va... 相似文献
145.
146.
长江口外海域三维水动力模拟结果及与观测的比较 总被引:1,自引:0,他引:1
Base on ECOMSED model, a theree-dimensional hydrodynamic model is developed in the offshore area near the Changjing Estuary in the East China Sea. This model in driven by tide and wind,as well as inflow and outflowcurrents such as Kuroshio,Changjing runoff. The horizontal resolution is 1/20°. There have 11 layers on the verticaldirection. The numerical results of 4 main constituents of tide(M2,S2,K1,O1)and currents are in good agreement with observation data. Compared with 20 gauge stations,the mean absolute erroe between the caluclated M2 tidal amplitude and the observed oned is only 6.72cm; the mean absolute error of phased-lag is 5.23°.For S2,the mean absolute errors of amplitude and phased-lag are 3.67cm and 7.21°,respectively. The mean absolute errors of amplitude and phased-lag for K1 are 3.25cm and 6.63° For O1,the mean absolute error of calculation and observation is relatively small, amwith observation data measured during Aug., 2006 in the East China Sea.The correlation coeffiients of current between simulation and observation are greater than 0.75 generally. The three-dimensional hydrodynamic model develiped by this paper can well describe the characters of elevation and current in the offshore near the Changjiang Estuary and can be used as hydrodynamic background to simulate the suspend sediment transport in this sea area. 相似文献
147.
随着城市地下交通现代化建设的进程,多条地下铁路在地下立交的情况已越来越多.盾构施工难免会引起已建隧道底板的沉降变化.本文结合一实例,介绍了施工期间的沉降观测方法,对可能引起底板变形的原因进行了分析,对指导类似盾构施工起了实际的指导意义. 相似文献
148.
149.
EGM96和EGM2008地球重力场模型计算弹道扰动引力的比较 总被引:2,自引:2,他引:0
给出了利用地球重力场模型计算扰动引力以及重力场模型截断误差的公式,计算了36阶、360阶、2 160阶地球重力场模型在径向和水平方向的截断误差,并对36阶、360阶的EGM96和EGM2008重力场模型计算的弹道扰动引力矢量进行了分析和比较.结果表明,采用重力场模型计算扰动引力时,模型阶数和弹道点的高度越低,模型截断误差越大;EGM96和EGM2008模型的一致性随着模型阶数的升高而逐渐降低.总体来看,EGM2008模型的精度要好于EGM96模型. 相似文献
150.
This study utilizes the 62208000 Swarm satellite data to establish a high-precision main magnetic field at the height of the satellites in China and its adjacen... 相似文献