动态最小二乘支持向量机学习算法     

邓兴升  花向红 《武汉大学学报(信息科学版)》2008,33(11):1122-1125

针对大样本集的训练问题和动态训练样本的模型更新问题,提出了动态最小二乘支持向量机学习算法.该算法充分利用已建好的模型,逐渐加入新样本,并可删除位于任何位置的非支持向量,避免了矩阵求逆运算,保证了算法的高效率.大坝变形及电离层延迟两个时间序列的预报实例表明,该算法具有计算时间短、预报精度高的特点.  相似文献   

葛店矿双庙扩大区三维地震勘探     

张彦湘 《中国煤炭地质》2008,20(2):53-56

葛店煤矿双庙扩大区位于豫、皖两省交界处。勘探区为一轴向北北东向的不对称向斜构造,地层倾角26°～30°,测区深部有岩浆岩侵入体,严重影响煤层赋存形态;地表条件复杂,村庄密集、河流较多,测区东侧塌陷区水塘大面积分布．三维地震勘探野外施工难度大。本区地震勘探观测系统设计为12线18炮制,为避免偏移归位及叠加次数降低等问题,在向斜轴部两侧、村子周边及河岸处适当加密炮点,并在塌陷区利用钢钎插置检波器以保证CDP点完整性。数据处理采取了叠前反褶积、叠前时间偏移等技术,数据处理效果显著。遵循多波组对比、多个数据体综合解释的原则,以纵向、横向和任意时间剖面相结合,充分利用三维可视化技术进行地震资料解释。本次勘探成果查明了主采煤层三2^2、二2煤层的构造形态及埋藏深度;解释落差5m以上断层34条,其中修改原有断层5条;另外新发现小于5m的异常断点22个。经巷道验证煤层底板标高误差0．43％～1．96％,巷道已揭露断层7条,与解释成果基本一致。  相似文献   

叠前时间偏移方法在煤田勘探中的应用     

冷广升  陈加林  王秀荣  杜宏  车建英  朗玉泉 《中国煤炭地质》2008,(6):40-43

根据克希霍夫积分法的原理,介绍了叠前时间偏移的方法特点,实现过程,以及对地震资料的要求,依托国家重大产业技术专项“西部煤炭资源高精度三维地震勘探”工程,对“青海省鱼卡煤田四井田高精度三维地震勘探”资料进行叠前时间偏移,结果表明其能较好地解决成像质量差、能量聚焦不明显、绕射波收敛不理想等方面的难题。通过与叠后时间偏移对比,对于大倾角地层、断块小且多的破碎带、陡倾角不对称向斜等地质问题,其叠前时间偏移剖面成像质量都有明显的提高,反映的构造关系更加清晰,同相轴连续性增强。总结该方法在多个矿区的推广经验．认为合理的观测系统、较高的资料信噪比,准确的测量资料及较高的中表层速度调查精度是做好叠前时间偏移的前提。  相似文献   

第二次土地调查若干问题探讨   总被引：1，自引：0，他引：1  

杨卫国 《现代测绘》2008,31(4)

第二次土地调查的目的是全面查清全国土地利用状况,掌握真实的土地基础数据,如何保证调查的质量?文章以江阴市为例进行探讨。  相似文献   

Group Time Delay in the Reflection of P-Polarized Electromagnetic Plane Waves at a Stratigraphic Interface     

Fu-Ping Liu  Rui-Zhong Li  Jin-yao Li  Hui-Guo Chen  Chang-Chun Yang 《Mathematical Geosciences》2008,40(7):813-829

The group time delay (GTD) formulae of quasi-total reflection of inhomogeneous P-polarized electromagnetic waves (P-PEW, whose electric field parallels to the plane of incidence), caused by the Goos–Hänchen effect, is derived by the phase shift of the wave. A numerical example where the frequency equals to 1 GHz is given. The curves of calculating results show that there are three discontinuous points at the critical angle of phase shift vector, the critical angle of attenuation vector and 90^○. When the angle of incidence is equal to one of these three angles, the GTD will become infinite, and the electromagnetic wave will propagate along the interface. The GTD will be very large, when the angle of incidence is close to one of these three angles. The results indicate that there is an important relationship between the two critical angles and the conductivity and permittivity of the two strata, and that the GTD has an important relationship with the angle of incidence. These results can be used to determine the lithology of the strata and to delimit the interfaces of strata more effectively. It is suggested that this research may prove useful in electromagnetic logging analysis and, perhaps, in the design of logging instruments.  相似文献   

中国短期气候变化的一个重要原因——青藏高原地表反射率的变化   总被引：5，自引：0，他引：5  

刘晓东  马柱国 《热带气象学报》1996,12(3):240-245

通过数值试验对高原地表反射率变化的气候效应进行了敏感性研究,同时对观测的近４０年中国区域气候变化趋势作了对比分析。结果表明,高原主体地表反射率增加是我国短期气候变化的重要控制因子之一,它能造成东亚夏季风和高原夏季风的显著减弱,使夏季我国东部季风区北方变暖,南方变冷,季风降水普遍减少。  相似文献   

随钻测录井地质导向二维分解实时绘图方法     

邵才瑞  原野  张福明  陈国兴  曹先军 《吉林大学学报(地球科学版)》2021,51(1):256-265

根据随钻测录井实时地质导向和大斜度、水平井评价成图技术需求，针对传统绘图方法存在的弊端，提出了将测录井信息、井眼轨迹和地质模型进行二维分解的实时绘图方法。针对二维分解绘图方法绘图时空复杂度较高的问题，给出了不同事件驱动下的局部实时计算和拷屏重绘算法，控制了对CPU和内存的消耗、提高了绘图效率，消除了实时绘图的闪烁和卡顿现象。应用实例表明，二维分解实时绘图方法能够实现大尺度随钻测录井地质导向图形的流畅、无卡顿实时绘图，可提高大斜度、水平井储层模型评价的刻画精度和时效。  相似文献   

Seasonal variations of atmospheric sulfur dioxide and dimethylsulfide concentrations at Amsterdam Island in the southern Indian Ocean     

J. P. Putaud  N. Mihalopoulos  B. C. Nguyen  J. M. Campin  S. Belviso 《Journal of Atmospheric Chemistry》1992,15(2):117-131

Daily measurements of atmospheric sulfur dioxide (SO₂) concentrations were performed from March 1989 to January 1991 at Amsterdam Island (37°50 S–77°30 E), a remote site located in the southern Indian Ocean. Long-range transport of continental air masses was studied using Radon (²²²Rn) as continental tracer. Average monthly SO₂ concentrations range from less than 0.2 to 3.9 nmol m^-3 (annual average = 0.7 nmol m^-3) and present a seasonal cycle with a minimum in winter and a maximum in summer, similar to that described for atmospheric DMS concentrations measured during the same period. Clear diel correlation between atmospheric DMS and SO₂ concentrations is also observed during summer. A photochemical box model using measured atmospheric DMS concentrations as input data reproduces the seasonal variations in the measured atmospheric SO₂ concentrations within ±30%. Comparing between computed and measured SO₂ concentrations allowed us to estimate a yield of SO₂ from DMS oxidation of about 70%.  相似文献   

中国大陆第四纪地壳运动时程   总被引：5，自引：0，他引：5  

冯希杰 《地质论评》1992,38(3):210-214

本文从中国大陆有代表性的青藏高原、黄土高原、三峡地区着手,进行了新构造运动剖析。并结合全国火山活动期次,总结出中国大陆第四纪地壳运动的时程变化。从而为进一步探讨新构造运动特点和规律,为国民经济建设及人类生存环境提供了一定的地质背景资料。  相似文献   

The concentration and distribution of different mercury species in the water columns and sediment of Aha Lake     

Weiyang BAI Xinbin FENG Xuewu FU Tianrong HE Guangle QIU 《中国地球化学学报》2006,25(B08):154-154

In order to find out whether Aha Lake was polluted by the acid mining waste water or not, the concentration and distribution of different mercuryspecies in the water columns and sediment profile collected from Aha Lake were investigated. It was found that discernible seasonal variation of different mercury species in water body were obtained in the Aha Reservoir. With regards to the whole sampling periods, the concentrations of HgP in the Aha Reservoir water body were evidently correlated to the concentrations of total mercury, showing that total mercury was mostly associated with particle mercury. The concentrations of methylmercury in water body were also evidently correlated to the concentrations of dissolved mercury. The dissolved mercury evidently affects the distribution and transportation of methylmercury. However, there is no correlation between methylmercury and total mercury. The dissolved mercury, reactive mercury, dissolved methylmercury levels in the water body of high flow period were much higher than those in low flow period. The distribution, speciation and levels of mercury within the Aha Reservoir water body were governed by several factors, such as the output of river, the release of sediment . Discernible seasonal variation of total mercury and methylmercury in porewater was described during the sampling periods, with the concentrations in high flow period generally higher than those in low flow period. The methylmercury in pore water column was evidently correlated to that of the sediment. The results indicated that highly elevated MeHgD concentrations in the porewater were produced at the depths from 2 to 5 cm in the sediment profile, and decreased sharply with depth. A positive correlation has been found between MeHgD formation and sulfate reducing bacterial activity. These highly elevated concentrations of MeHgD at the intersurface between waters and sediments suggest a favorable methylation condition. Moreover,  相似文献