基于PSR-WSVM模型的边坡位移预测

为建立高精度的边坡位移预测模型，采用相空间重构（PSR）将边坡位移时间序列数据转换为多维数据，同时构造小波核函数改进的支持向量机模型，建立PSR-WSVM模型并应用于边坡位移预测。将PSR-WSVM模型预测结果与传统支持向量机（SVM）模型、小波支持向量机（WSVM）模型和基于相空间重构的支持向量机（PSR-SVM）模型预测结果进行对比，通过平均绝对误差（MAE）、平均绝对误差百分比（MAPE）和均方根误差（RMSE）3个精度评价指标验证PSR-WSVM模型的可行性。工程实例结果表明，PSR-WSVM模型预测结果的3个精度评价指标都优于另外3种模型，边坡位移预测的精度明显提升。     

关于t-模的生成

讨论了概率度量空间中ｔ－模生成的概率意义。对构造ｔ－模提供了具体方法，并以实例介绍了这种构造方法。     

Is there a link between deep‐sea biodiversity and ecosystem function?

Studying the diversity‐ecosystem function relationship in the deep sea is of primary importance in the face of biodiversity loss and for our understanding of how the deep sea functions. Results from the first study of diversity‐ecosystem function relationships in the deep sea (Danovaro et al. 2008; Current Biology, 18, 1–8) are unexpected and show an exponential relationship between deep‐sea nematode diversity and ecosystem function and efficiency, although this relationship appears largely restricted to relatively low diversities [ES(51) <25]. Here, we investigate the relationship between nematode diversity and several independent measures/proxies of ecosystem function (sediment community oxygen consumption, bacterial biomass, bacterial extracellular enzyme activity) and efficiency (ratio of bacterial/nematode carbon to organic C content of the sediment) on the New Zealand continental slope. Nematode diversity at our study sites was relatively high [ES(51) = 30–42], and there was no relationship between species/functional diversity and ecosystem function/efficiency after accounting for the effects of water depth and food availability. Our results are consistent with a breakdown of the exponential diversity‐function relationship at high levels of diversity, which may be due to increased competition or greater functional redundancy. Future studies need to take into account as many environmental factors and as wide a range of diversities as possible to provide further insights into the diversity‐ecosystem function relationship in the largest ecosystem on Earth.     

The effect of El Niño Southern Oscillation cycles on the decadal scale suspended sediment behavior of a coastal dry‐summer subtropical catchment

Rivers display temporal dependence in suspended sediment–water discharge relationships. Although most work has focused on multi‐decadal trends, river sediment behavior often displays sub‐decadal scale fluctuations that have received little attention. The objectives of this study were to identify inter‐annual to decadal scale fluctuations in the suspended sediment–discharge relationship of a dry‐summer subtropical river, infer the mechanisms behind these fluctuations, and examine the role of El Niño Southern Oscillation climate cycles. The Salinas River (California) is a moderate sized (11 000 km²), coastal dry‐summer subtropical catchment with a mean discharge (Q_mean) of 11.6 m³ s^?1. This watershed is located at the northern most extent of the Pacific coastal North America region that experiences increased storm frequency during El Niño years. Event to inter‐annual scale suspended sediment behavior in this system was known to be influenced by antecedent hydrologic conditions, whereby previous hydrologic activity regulates the suspended sediment concentration–water discharge relationship. Fine and sand suspended sediment in the lower Salinas River exhibited persistent, decadal scale periods of positive and negative discharge corrected concentrations. The decadal scale variability in suspended sediment behavior was influenced by inter‐annual to decadal scale fluctuations in hydrologic characteristics, including: elapsed time since small (~0.1 × Q_mean), and moderate (~10 × Q_mean) threshold discharge values, the number of preceding days that low/no flow occurred, and annual water yield. El Niño climatic activity was found to have little effect on decadal‐scale fluctuations in the fine suspended sediment–discharge relationship due to low or no effect on the frequency of moderate to low discharge magnitudes, annual precipitation, and water yield. However, sand concentrations generally increased in El Niño years due to the increased frequency of moderate to high magnitude discharge events, which generally increase sand supply. Copyright © 2014 John Wiley & Sons, Ltd.     

井地地震CT成像数值模拟研究与应用

由井地地震CT成像原理决定,其在提高生产效率、降低生产成本和扩大勘察范围上具有突出优势.本文针对井地观测系统,重点通过对ART和SIRT重建方法进行数值模拟对比研究,分析得出二者在井地地震CT应用中的优缺点及适用条件,提出了如何提高影响成像质量的射线分布密度、均匀性和正交性.最后选择收敛快速稳定的SIRT算法应用于实际,取得良好的生产效果,很好的验证了井地CT成像技术的正确性,可行性和实用性.     

Upper Holocene sea-level changes: Paleogeographic evolution and its impact on coastal archaeological sites and monuments

The paper presents the evolution of the geographic environment imposed by sea-level changes in selected sites of the Aegean Sea region during the Upper Holocene. The changes are due, mainly, to paroxysmic phases of the actual neotectonic evolution and to differential—in time and space—block movements, and emerged or submerged coasts. The reconstitution of these coasts is presented and, in some cases, natural harbor morphology is revealed. The use and evolution of these sites is discussed. Other sites concern coastal or inland ancient settlements or constructions affected by submersion by the sea, by the rise of the groundwater table, or by uplift movements. A general discussion on engineering measures to be applied for protection of the antiquities affected by these geographic changes closes the presentation.     

基于模态逼近的EOF重构算法重建公元1250年以来北半球地表气温空间格局

随着气候场重建数据在揭示气候动力机制以及与数值模式模拟相结合等方面的应用, 它在气候变化研究领域中的实用性和重要性已得到广泛认可。因此, 关于空间格局重建方法的研究也就显得尤为重要。本文提出了一种新的气候场重建方法, 即模态逼近的经验正交函数分解方法。该方法利用代用资料与器测资料不同空间模态之间的协调性, 采用模态逐次逼近, 从而实现对过去无器测资料覆盖的气候场的重建。基于该方法, 本文利用549个树轮序列重建了北半球(22.5°N以北)公元1250年以来的地表气温空间场。为验证该方法的有效性, 设计了多组验证试验, 结果均表明该重建方法能够较好的再现器测数据的年代际尺度变率特征。最终重建结果表明, 与已有研究结果相比, 该方法重建出的北半球小冰期(1400~1700年)平均气候状态的空间格局特征与基于多组气候模式集合平均在该时段的模拟结果更为接近。另外, 为体现重建结果对外强迫的响应特征, 本文比较了在不同强度(强、中等、弱)典型火山年的空间格局差异, 发现高纬度地区对火山外强迫相比于中低纬地区更加敏感, 这与已有的基于数值模式模拟研究的结论基本一致。综合以上讨论, 证明了该方法在气候场重建方面的有效性和应用潜力。     

智能地质调查体系与架构

中国地质调查局用了近10年时间,在基础地质调查和矿产调查领域基本完成了地质调查全流程数字化过程。在"云"计算与大数据技术等新一代信息技术的兴起大环境下,未来5至10年,地质调查主流程信息化的方向和目标是什么呢?本文基于新一代信息智能技术和智能设备在地质调查数据采集、数据分析处理、数据交换传输、三维建模、信息泛在服务、业务管理全面深度融合的基础上,结合智能空间与普适计算概念给出了智能地质调查定义,提出了基于云计算和Hadoop生态体系为基础的天地空一体化的智能地质调查体系、架构和应用模式,并对其关键技术进行了讨论。     

A rooftop tuned mass damper frame

This article documents the analytical study and feasibility of placing a tuned mass damper in the form of a limber rooftop moment frame atop relatively stiff structures to reduce seismic acceleration response. Six existing structures were analytically studied using a suite of time history and response spectra records. The analyses indicate that adding mass in conjunction with a limber frame results in an increase in the fundamental period of each structure. The fundamental period increase generally results in a decrease in seismic acceleration response for the same time history and response spectra records. Owing to the limber nature of the rooftop frames, non‐linear analysis methods were required to evaluate the stability of the rooftop tuned mass damper frame. The results indicate the addition of a rooftop tuned mass damper frame reduces the seismic acceleration response for most cases although acceleration response can increase if the rooftop frame is not tuned to accommodate the specific structure's dynamic behaviour and localized soil conditions. Appropriate design of the rooftop tuned mass damper frame can result in decreased seismic acceleration response. This translates to safer structures if used as a retrofit measure or a more economical design if used for new construction. Copyright © 2003 John Wiley & Sons, Ltd.     

地质灾害监测预警中的精密空间对地观测技术

21世纪以来,随着世界环境恶化和人类活动剧烈,地质灾害呈现频发态势,精密对地观测技术成为其监测预警的重要手段。本文首先介绍了常见地质灾害特点和监测方法,并对InSAR、LiDAR、高分遥感和GNSS 4种技术在地质灾害监测预警中的技术特点及应用进行了阐述,其次对高精度空间监测技术融合进行了综述和展望,最后对未来地质灾害监测预警技术趋势进行了总结。