共查询到19条相似文献，搜索用时 140 毫秒
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基于POM模式的"blending"同化法,构建了天津港及附近海域分辨率为1'×1'、13个主分潮的精密潮汐模型。构建过程中重点关注水深数据格网化与潮汐模型的精度评估。水深数据格网化过程基于尽量扩大覆盖范围、分辨率与水深数据相匹配以及保持岸线形状基本不变等原则。潮汐数值模拟过程采用分批同化T/P点与验潮站,实现对潮汐模型精度的可靠评估。经估计,在天津港附近的9个主分潮RSS在10cm内。 相似文献
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针对当前构建高精度数字水深模型中常用的格网数据索引方法,在海量数据管理中存在因树的规模限制而导致检索效率低的问题,提出了一种格网树与KD树(K-Dimension,KD)组合的水深数据索引方法。首先,利用格网将水深源数据分割为网状的数据块,构建出数据块的格网树;其次,构建各数据块的KD树,实现对数据块中任意数据的快速索引;最后,通过快速定位数据块,查找其所在KD树的位置,实现对海量数据的快速检索。实验结果表明:①与格网树相比,本文所提组合检索方法的检索效率随检索树规模的变化不明显;②在相同的数据量下,组合树的检索效率要普遍高于格网树方法。 相似文献
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CUBE算法及其在多波束数据处理中的应用 总被引：5，自引：0，他引：5
阐述了一种基于表面生成的多波束数据处理方法——CUBE(Combined Uncertainty and Bathymetry Estimator)算法,用该方法可以对观测区域网格节点"真实"水深及相关误差进行估计。与从测量水深中选择出"最佳"数据的手工交互方式的多波束数据编辑手段不同,CUBE算法具有很强的抗差性和较高的效率,适合于实时多波束数据处理。对南海某测区多波束数据处理结果表明,在没有人工干预的情况下,利用CUBE算法去噪生成的海底DTM图与手工编辑生成的相当吻合。CUBE算法和手工编辑方法综合对比得出,CUBE算法能够很好地保留水深地形细节,在计算效率、误差评估、实时处理等方面比手工编辑方法具有较大的优势。 相似文献
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针对当前高密度多波束水深数据抽稀后所构建数字水深模型(digital depth model,DDM)的航海安全性缺少估计这一问题,分别以最浅点法、最近点法和平均值法3种常用方法抽稀水深数据并构建DDM,在此基础上,分析不同抽稀方法所构建DDM随尺度变化的深度保证率变化规律,采用统计分析的方法建立DDM深度保证率与抽稀尺度、海底地形复杂因子之间的数学回归模型。实验表明:该回归模型不仅可用于估算基于不同抽稀方法所构建DDM的深度保证率,也为确定满足适合的DDM深度保证率所需要的抽稀尺度提供了理论依据。 相似文献
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基于CUBE算法的多波束测深数据自动处理研究 总被引：1，自引：0，他引：1
对CUBE算法自动处理多波束测深数据的模型建立、格网节点的多重估计和最优估值选取准则进行了详细介绍,深入分析了多重估计的实用性,并通过实测数据对该算法进行实现.利用了抗差Kalman滤波改进CUBE算法.通过模拟数据对改进的CUBE算法进行实验,验证了算法改进的必要性. 相似文献
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Tsung-Lin Lee Ching-Piao Tsai Hung-Ming Lin Chi-Jen Fang 《Ocean Engineering》2009,36(15-16):1251-1257
An application of an artificial neural network (ANN) combined with thermographic analysis for estimating the depth of eroded caves in a seawall is presented in this paper. A model experiment was first conducted in a sandbox using a thermographic device to detect the interior conditions of a structure from its temperature changes measured on the surface. The temperature difference calculated from the air temperature and the measured concrete surface point on a thermographic image was obtained for the neural network. Based on the laboratory data, an optimum ANN model for the estimation of the depth of eroded caves in a seawall was established by using four input factors: the site temperature, humidity, thermographic area, and the temperature difference. The model was verified using data from a seawall in Tainan City, Taiwan. From the results, it was found that the present ANN model efficiently estimates the depth of eroded caves in a seawall. 相似文献
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An accurate estimation of scour depth around piles is important for coastal and ocean engineers involved in the design of marine structures. Owing to the complexity of the problem, most conventional approaches are often unable to provide sufficiently accurate results. In this paper, an alternative attempt is made herein to develop adaptive neuro-fuzzy inference system (ANFIS) models for predicting scour depth as well as scour width for a group of piles supporting a pier. The ANFIS model provides the system identification and interpretability of the fuzzy models and the learning capability of neural networks in a single system. Two combinations of input data were used in the analyses to predict scour depth: the first input combination involves dimensional parameters such as wave height, wave period, and water depth, while the second combination contains nondimensional numbers including the Reynolds number, the Keulegan–Carpenter number, the Shields parameter and the sediment number. The test results show that ANFIS performs better than the existing empirical formulae. The ANFIS predicts scour depth better when it is trained with the original (dimensional) rather than the nondimensional data. The depth of scour was predicted more accurately than its width. A sensitivity analysis showed that scour depth is governed mainly by the Keulegan–Carpenter number, and wave height has a greater influence on scour depth than the other independent parameters. 相似文献
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A number of existing models for surface wave phase speeds (linear and non-linear, breaking and non-breaking waves) are reviewed and tested against phase speed data from a large-scale laboratory experiment. The results of these tests are utilized in the context of assessing the potential improvement gained by incorporating wave non-linearity in phase speed based depth inversions. The analysis is focused on the surf zone, where depth inversion accuracies are known to degrade significantly. The collected data includes very high-resolution remote sensing video and surface elevation records from fixed, in-situ wave gages. Wave phase speeds are extracted from the remote sensing data using a feature tracking technique, and local wave amplitudes are determined from the wave gage records and used for comparisons to non-linear phase speed models and for non-linear depth inversions. A series of five different regular wave conditions with a range of non-linearity and dispersion characteristics are analyzed and results show that a composite dispersion relation, which includes both non-linearity and dispersion effects, best matches the observed phase speeds across the domain and hence, improves surf zone depth estimation via depth inversions. Incorporating non-linearity into the phase speed model reduces errors to O(10%), which is a level previously found for depth inversions with small amplitude waves in intermediate water depths using linear dispersion. Considering the controlled conditions and extensive ground truth, this appears to be a practical limit for phase speed-based depth inversions. Finally, a phase speed sensitivity analysis is performed that indicates that typical nearshore sand bars should be resolvable using phase speed depth inversions. However, increasing wave steepness degrades the sensitivity of this inversion method. 相似文献
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The reliable estimation of the local scour depth at a bridge pier is essential for proper design and maintenance of bridge piers. Most local scour formulae have been developed based on the results of laboratory experiments. The formulae based on laboratory data do not often produce reasonable predictions for field piers because laboratory investigations are apt to oversimplify or ignore many of the complexities of the flow fields around the bridge piers. Validation of the formulae is necessary in order to ascertain which of the formulae are able to provide reasonable estimates of the local scour depth. In this study, six commonly cited formulae based on laboratory data or field data were selected for validation using 180 laboratory data sets gathered from the literature and 446 field data sets collected from four countries. The six formulae validated in this paper are the Colorado State University (CSU), Neill, Froehlich, Breuser, Laursen, and simplified Chinese formulae. Comparisons between the predicted and measured depths were performed using scour from the laboratory and field data. An artificial neural network technique was also applied in order to compare the tendencies between the field and laboratory data sets. 相似文献