适用于遥感图像分类的对偶子空间分类器

本文在子空间分类器的基础上，对子空间的概念进行了扩展，提出了对偶子空间的概念和相应的分类算法。这种分类器不仅保持了子空间分类器分类准确度高的特点，而且分类速度有很大提高，因而更适用于大规模的遥感图像分类。     

Hilbert transform in the interpretation of magnetic anomalies of various components due to a thin infinite dike

The Hilbert transformH(x) applicable to vertical (Z), horizontal (H), and total (T) magnetic anomalies due to a thin dike of infinite depth extent is derived from the generalised expression of magnetic effectF(x). The depth and dip of the dike is extracted by a simple procedure making use ofF(x) andH(x). A modified version of the amplitude of the analytic signal is given to locate the origin. The abscissa of the point of intersection ofF(x) and the discrete Hilbert transformH(1.x) directly yields the depth to the top. An example for each case is considered theoretically to illustrate the process. Applicability of the method is examined on the vertical component of the well-known magnetic anomaly at Kiirunavaara in northern Sweden, originally described by Von Carlheim Gyllenskjold, as well as on total magnetic anomaly of Bensons Mines, U.S.A.     

Radon signals related to seismic activity in Ecuador,March 1987

A radon concentration measurement survey was carried out in Ecuador using the SSNTD technique. The data analysis shows a definite radon anomaly prior to March 6, 1987;M=6.9 earthquake. Anomalies found before October 18 and October 28th mild earthquakes in 1986 could be correlated with these events. Other anomalies that we cannot correlate with any geophysical event were also found.     

地震信号内插与噪音剔除（二）

本文是文献[1]的续篇。前文已介绍一维情况下的信号内插的最佳内插算子,提出了一种可以在空间域较彻底地剔除干扰波的检噪算子。本文将其推广到二维情况,讨论二维F-K域中的信号内插及噪音剔除技术。二维噪音剔除可以在信噪比很低的记录上分离出信号来。通过试验说明,噪音剔除比常规的二维滤波好。     

Crustal thickness variations in the Eastern Mediterranean and southern Aegean region

In this paper, regional analog gravity anomaly map obtained from the General Directorate of Mineral Research and Exploration (MTA) was digitized and used for the calculation of the crustal thickness (Moho depth) variations in the Eastern Mediterranean and the southern part of the Aegean Region. In the gravity anomaly map, there are mainly E–W trending apparent gravity anomalies represented by the contours up to 150 mGal. They are generally parallel to the shorelines of Africa, Turkey and Crete. Crustal thickness variations were calculated from the gravity anomalies, using an empirical equation in this study. Obtained thicknesses (Moho depths) were mapped and correlated with the previous investigations and seismological findings. According to the estimations, crustal thicknesses are about 25–30 km along the coastal regions and more than 30 km on the onshore part of Turkey increasing up to 42 km through the eastern Anatolia. However, there are thin crustal zones around 17 km in the offshore Egypt, to the NW part of Cyprus and about 19 km to the north of Crete. They may be related with the main tectonic trends in this region except the circular thinning to the south of Kas (southwestern part of Turkey). In order to determine the locations and boundaries of prominent tectonic elements, Analytic Signal (AS) and maxspots maps of the gravity anomalies were also prepared in this study. All produced maps are generally consistent to each other and the boundaries of main tectonic units were apparently illustrated in the maxspots map from the horizontal gradient of Bouguer anomalies.     

东亚夏季风强度的多尺度统计预测模型

东亚夏季风强度的变化与中国雨带和旱涝分布密切相关。为了做好东亚夏季风强度的短期气候预测,采用小波分析、Lanczos滤波器、交叉检验等方法,研究了东亚夏季风强度的多尺度变化特征,在年际与年代际尺度上分别寻找了它在前冬海温场、200 hPa纬向风场上的前兆信号,并利用最优子集回归建立了东亚夏季风强度的多尺度统计物理预测模型。结果表明:东亚夏季风强度存在准4年、准13年和准43年的周期振荡。年际尺度上,前冬赤道东太平洋(10°N~10°S,160°W~80°W)海温与东亚夏季风强度有最强的显著负相关,且它与东亚夏季风强度在200 hPa纬向风场上的前兆信号有较强的负相关;年代际尺度上,南半球60°S与35°S附近200 hPa纬向风之差与东亚夏季风强度有最强的显著正相关,且它与东亚夏季风强度在热带印度洋、低纬度东南太平洋、低纬度南大西洋的海温及亚洲副热带200 hPa纬向风等前兆信号有强的正相关。通过探讨这两个前兆因子对东亚夏季风强度的预测意义,揭示了他们影响东亚夏季风强度年际和年代际变化的可能物理过程。所建立的东亚夏季风强度多尺度最优子集回归预测模型,不仅对东亚夏季风强度的年际变化具有较好的预测能力,而且对异常极值年份也具有一定的预测能力。     

应用小波变换提取林甸5.1级地震的前兆异常信息

应用了小波变换理论,对2005年林甸地震的前兆数据进行分析,研究在不同尺度下前兆数据的细节变化。结果表明,小波变换的多尺度分析方法将前兆数据分解成若干频段,容易识别和提取原始测值中不易分辨的震前异常,提高了识别前兆数据异常的能力。     

多匝回线的自感对瞬变电磁早期信号的影响特征

为了研究瞬变电磁早期信号的特性,这里讨论了多匝线圈与单匝线圈的自感系数的关系,同时也分析了瞬变电磁线圈等效回路的暂态过程,以及多匝线圈感应电动势的响应特征。最后,得出了影响早期信号的因素,为提取早期数据的研究提供参考。     

2005年中国减灾新课题

2005年中国减灾出现了一些新的课题:①出境中国公民的公共安全由谁来保护?②沙兰镇灾难显示出现行教育体制使得学生的分数倍受重视而其安全被忽视。③海南“达维”台风灾害显示出当前中国减灾面临的最大问题之一是救灾投入过低。④上海发布的黑色台风预警与国际预警信号不符,如何维护中央政令统一,进而维护国家发展大局,成为一个需要关注的问题。⑤启动地震应急预案的最小地震震级成为需研究确定的问题。⑥农村公共建筑的抗震问题应受到重视。⑦北方地区应将政府机关、体育场、学校等设为应急避难场所。     

地震资料保边的最大一致性倾角扫描去噪方法

在石油天然气勘探开发中,由于断层和裂缝等地质特征是发现和描述油藏的基础,所以分辨和分析地震数据中这些地质特征是非常重要的。本文提出的一种保边界的最大一致性倾角扫描去噪方法,可以在很好地保留地质边界特征的情况下,有效地压制噪音,准确地拾取地层倾角信息,提高油气藏识别的精度。