嵌入式GIS导航系统中快速偏航算法的设计与实现

诸如汽车拉力赛等特殊领域的车载导航系统中,需要在资源有限的嵌入式GIS平台上,满足地图快速刷新前提下实现偏航算法的实时性,为此本文改进了比较耗时的欧氏浮点距离计算公式,采用定点整型数描述空间位置,并用移位运算代替乘除计算.理论分析和测试结果表明,改进算法带来的相关误差符合导航需求,改进算法显著提高了一般偏航算法的实时性...     

Evaluation of the compression index of soils using an artificial neural network

The compression index is a one of the important soil parameters that is essential to geotechnical designs. As the determination of the compression index from consolidation tests is relatively time-consuming, empirical formulas based on soil parameters can be useful. Over the decades, a number of empirical formulas have been proposed to relate the compressibility to other soil parameters, such as the natural water content, liquid limit, plasticity index, specific gravity, and others. Each of the existing empirical formulas yields good results for a particular test set, but cannot accurately or reliably predict the compression index from various test sets. In this study, an alternative approach, an artificial neural network (ANN) model, is proposed to estimate the compression index with numerous consolidation test sets. The compression index was modeled as a function of seven variables including the natural water content, liquid limit, plastic index, specific gravity, and soil types. Nine hundred and forty-seven consolidation tests for soils sampled at 67 construction sites in the Republic of Korea were used for the training and testing of the ANN model. The predicted results showed that the neural network could provide a better performance than the empirical formulas.     

潜水完整井抽水时水跃值研究

针对艾连别格尔水跃值经验公式,用最小二乘法对其进行修正。通过实例对修正前后两公式进行验证,得出如下结论：艾连别格尔的水跃值经验公式过于保守,误差很大,而经最小二乘法修正后的公式能更好的反应实际情况,误差明显减小。说明修正后的公式更适用于实际工程。     

基坑空间效应影响区长度的探讨

基坑空间效应影响范围的确定对其支护方案的选择、施工方案的确定以及监测方案的设置具有较强的指导意义。通过对不同基坑空间效应计算模型的分析,基于新的三维滑楔体破坏模型,提出了空间效应影响区长度的计算公式。三种计算方法的比较分析表明,新的计算方法更全面的考虑了影响基坑空间效应的各种因素,计算过程较为简便,且计算结果能较好地符合监测结果。     

Predicting wave run-up on rubble-mound structures using M5 model tree

Prediction of run-up level is a key task in design of the coastal structures. For the design of the crest level of coastal structures, the wave run-up level with a 2% exceedance probability, R_u2%, is most commonly used. In this study, the performance of M5 model tree for prediction of the wave run-up on rubble-mound structures was investigated. The main advantage of model trees, unlike the other soft computing tools, is their easier use and more importantly their understandable mathematical rules. Experimental data set of Van der Meer and Stam was used for developing model trees. The conventional governing parameters were selected as the input variables and the obtained results were compared with Van der Meer and Stam’s formula, recommended by the Coastal Engineering Manual (CEM, 2006). The predictive accuracy of the model tree approach was found to be superior to that of Van der Meer and Stam’s empirical formula. Furthermore, to judge the generalization capability of the model tree method, the model developed based on laboratory data set was validated with the prototype run-up measurements on the Zeebrugge breakwater, Belgium. Results show that the model tree is more accurate than empirical formulas and TS Fuzzy approach in estimating the full-scale run-up.     

海岸线长度量算方法的研究

海岸线是重要而宝贵的自然资源,准确量算海岸线长度是摸清海洋家底和实施有效管理的前提.但目前海洋界没有统一的海岸线长度量算方法.提出基于高斯平均引数的椭球面长度算法,并采用MapBasic语言的实现海岸线长度的自动化计算,通过验证和比对,比目前海洋界普遍采用的平面长度算法更准确,可在实际工作中推广.     

Penman－Monteith公式中冠层阻抗的合成方法

根据有关学者提出的几种植冠阻抗参数化的代表性理论，由单叶气孔阻抗实测值，结合叶面积垂直分布资料，提出了３种计算冠层阻抗的合成方法。利用由Ｐ－Ｍ公式反推出的冠层阻抗及由波文比仪测算出的麦田蒸散值对各合成方法进行了效果分析。     

二维地表相邻多个半圆弧沟谷对SH波的散射

本文由解析法研究了二维地表相信多个圆弧沟谷对稳态ＳＨ波的散射问题。文中把相邻多个圆弧沟谷对波的多重散射表达为各局部坐标的Ｆｏｕｒｉｅｒ－Ｂｅｓｓｅｌ级数之和，再利用Ｇｒａｆ加法公式在某一局部坐标中表达为双重级数形式，将问题归结为对一组线性方程的求解。最后，作为例子，给出了相信两圆弧沟谷对波散射的数值结果，讨论了沟谷对波的屏蔽、隔振作用及沟谷之间的相互作用。     

矩阵反演公式在分组平差教学中的应用

文献[1]从消去k_1后的整体平差的法方程中引出了分组平差的两种解法的概念,其它各种函数模型第二次平差时的第二种解法都是通过第一次平差与整体平差的第二种解法比较得出。本文应用矩阵反演公式,直接从第一种解法导出第二种解法的公式。在序贯平差中通过引入假观测值法,简化了第二种解法的公式推证过程。     

Lasky关系的统计地球化学背景

从统计地球化学出发，给出了矿石量品位吨位的经验关系理论表示；同时给出了金属量品位吨位关系的理论表示。这种解释比分维解释更贴近常人的经验。