应用一种改进BP神经网络算法预测密度曲线

利用测井数据与地震数据二者相结合进行综合分析,是地震勘探工作者的重要工作。可以通过分析井位处的地震数据与测井数据,提取地震的多个属性,建立一个与测井属性的统计关系。选取已改进的三层网络结构BP神经网络算法,在应用一个实际例子后表明,该算法的主要特点是收敛速度快、计算简单,同时还具有跳出局部最小的能力。应用此神经网络算法对某油田的二维地震数据进行了处理,提取了多种地震属性,并在井位置建立了地震属性与密度曲线的非线性关系,成功预测了剖面密度曲线,为了解储层状况提供了有益的资料。     

Southwest Scandinavia, 40–15 kyr BP: palaeogeography and environmental change

Twelve palaeogeographical reconstructions illustrate environmental changes at the southwest rim of the Scandinavian Ice Sheet 40–15 kyr BP. Synchronised land, sea and glacier configurations are based on the lithostratigraphy of tills and intertill sediments. Dating is provided by optically stimulated luminescence and calibrated accelerator mass spectrometry radiocarbon. An interstadial sequence ca. 40–30 kyr BP with boreo‐arctic proglacial fjords and subarctic flora and occasional glaciation in the Baltic was succeeded by a Last Glacial Maximum sequence ca. 30–20 kyr BP, with the closure of fjords and subsequent ice streams in glacial lake basins in Kattegat and the Baltic. Steadily flowing ice from Sweden bordered the Norwegian Channel Ice Stream. A deglaciation sequence ca. 20–15 kyr BP indicates the transgression of arctic waters, retreat of the Swedish ice and advance of Baltic ice streams succeeded by a return to interstadial conditions. When ameliorated ice‐free conditions prevailed in maritime regions, glaciers advanced through the Baltic and when interstadial regimes dominated the Baltic, glaciers expanded off the Norwegian coast. The largest glacier extent was reached in the North Sea around 29 kyr BP, about 22 kyr BP in Denmark and ca. 18 kyr BP in the Baltic. Our model provides new data for future numerical and qualitative landform‐based models. Copyright © 2003 John Wiley & Sons, Ltd.     

多源遥感影像像素级融合分类与决策级分类融合法的研究

首先探讨了基于像素的多源遥感影像高频调制融合法，根据成像系统特性和Heisenberg测不准原理，设计的高斯滤波器对高分辨率影像滤波的方法是合理有效的。在研究BP神经网络的基础上，采用动量法和学习率自适应调整的策略，提高了BP神经网络学习算法收敛速度，并增强了算法的可靠性。提出并实现了多源遥感影像像素级融合分类与决策级分类融合两种分类方法，并进行了比较。采用Landsat TM3，4，5和航空SAR影像进行试验，结果表明两种分类方法是行之有效的，均适用于多源遥感影像分类。     

小波神经网络在重磁资料反演中的应用前景

对BP神经网络在重力密度界面反演以及小波分析在位场分离上的应用进行了深入的研究,进而对小波神经网络在重磁资料反演中的应用前景进行了分析、评价。     

Sedimentary cycles of trace elements in Salawusu River Valley since 150 ka BP

The paper makes some analyses on 11 trace elements in the Milanggouwan stratigraphical section in the Salawusu River valley, which is regarded as a prototype geology-palaeoclimate record since 150 ka BP. The results show that the content and variation of trace elements has experienced remarkably regular changes in the pace with coarse and fine sedimentary cycles of palaeo-aeolian sands to its overlying fluvio-lacustrine facies or/and palaeosols. The trace elements with chemical properties of relatively active (V, Sr, Cu, Ni, As) and relatively stable (P, Pb, Rb, Mn, Nb, Zr) are a manifestation of the corresponding 27 changeable cycles between peak and valley values, appearing a multi-fluctuational process line of relative gathering and migration since then. The low numerical value distribution of these two types of trace elements in the aeolian sand facies represents erosion and accumulation under wind force during the cold-dry climate. Whereas their enrichments in both fluvio-lacustrine facies and palaeosols are related to the valley’s special low-lying physiognomic position between the Ordos Plateau and the Loess Plateau under the warm and humid climate conditions. The above relatively migrated and gathered change of the trace elements is the result of 27 climatic cycles of cold-dry and warm-humid, which is probably caused by repeated alternations of winter monsoon and summer monsoon in the Mu Us Sandy Land influenced by the climate vicissitudes in northern hemisphere during glacial and interglacial periods since 150 ka BP.     

基于BP神经网络的汛期降水预测模型研究

采用误差反传前向网络（简称BP神经网络）建立汛期（6-8月）降水预测模型，并与采用逐步回归方法建立的模型进行对比试验，结果表明，基于BP神经网络的汛期降水预测模型不仅对历史样本的拟合精度更高，而且其独立样本的预测检验效果也比逐步回归方法更好，是一种具有一定应用前景的汛期降水预测方法。     

基于神经网络的遥感影像分类研究

由于传统遥感影像分类方法存在不足，故采用BP神经元网络进行遥感影像分类研究。阐述了算法原理、实现步骤以及改进方法。通过实验示例，将BP神经元网络的分类结果与传统统计方法分类结果进行比较，获得了有意义的结果。     

Grain-size cycles in Salawusu River valley since 150 ka BP

Situated at the southeast Mu Us Desert on the Ordos Plateau of China, the Salawusu River valley, contains abundant environmental vicissitude information of the East Asia Monsoon since Late Quaternary and serves as an excellent site for researches of sedimentology and climatology etc. As early as 1924, the French paleontologists Teilhard de Chardin et al. found the Upper-Pleistocene Salawusu Formation and drew an outline of the 搃deal section through the loessic lands of N and the SE co…     

RCP情景下内蒙古黄河流域径流预估及其对水资源的影响

根据内蒙古黄河流域内72个国家气象站观测的1961—2005年和区域气候模式CCLM模拟的1961—2100年的气温和降水数据,采用BP人工神经网络模型,预估分析3种RCP情景下头道拐水文站2011—2100年流量变化,评估未来气候变化对流域水资源的可能影响。结果表明:①2011—2100年内蒙古黄河流域气温升高,降水变化不明显,年平均流量呈减少趋势,RCP2.6、RCP4.5和RCP8.5情景分别减少3.6%、2.7%和23.4%。②未来春季流量以增加为主;夏季在不同情景的变化趋势不一致;秋季在21世纪50年代前以增加为主,之后以减少为主;冬季则以减少为主。③未来流域可利用水资源呈减少趋势,尤其夏季水资源的供需矛盾加剧,以及径流季节分配发生变化,可能产生更大的春季径流。     

BP神经网络在地震综合预报中的应用

ＢＰ神经网络具有很强的非线性映射功能,它可以很好地反映震前出现的各类异常与未来地震震级及发震时间之间的较强非线性关系。在“地震预报智能决策支持系统”中使用了ＢＰ神经网络。介绍了该系统中的ＢＰ神经网络构成及其在地震预报中的应用,系统通过对实际震例的检验取得了较为理想的预报效果。