用高差变化量检验水准点稳定性的数表运算

本文介绍用高差变化量分析水准网点稳定性时数表运算的原理和方法，数表组构简单而性强，剔除动点后无需重新平差，操作便捷实用，适于任意两观测周期间比较，点数愈多判断愈准确。     

Study of main body element of crustal strain and its relationship with moderate-strong earthquakes

In this paper, progress in strain study of blocks and faults by GPS data are discussed, and the concept that active structures between blocks are the main body of crustal strain is clarified. By energy transfer principle of elastic mechanics, the relation between strain around faults and tectonic force on fault surfaces is set up and main body element model of crustal strain is constructed. Finally, the relation between mechanical evolution of model and seismogenic process of Kunlun earthquake （Ms=8.1） is discussed by continuous GPS data of datum stations. The result suggests that the relatively relaxed change under background of strong compressing and shearing may help to trigger moderate-strong earthquakes.     

城市控制网坐标转换的分析研究

城市控制网的改建融合了传统测绘技术与新技术,通过对不同技术手段下布设的控制网进行分析研究,建立一套符合实际现状、满足建设需求的坐标转换模型,实现原有的、相对精度较低的城市控制网与现代化的高精度控制网最佳的衔接。     

A new method of reduced order feedback control using Genetic Algorithms

Genetic Algorithms (GAs) have been applied as an effective optimization search technique in various fields, including the field of control design. In this paper, a new control method using GAs is proposed to attenuate the responses of a structure under seismic excitation. The proposed controller uses the state space reconstruction technique based on the embedding theorem to obtain full state performance from the available reduced order feedback. The parameters of the new controller are optimized using GAs. The proposed GA-based control method is verified on a benchmark problem—active mass driver system—and the results are compared with other control methods. The robustness of the proposed control method is also examined. Copyright © 1999 John Wiley & Sons, Ltd.     

中国空间辐射测量基准技术

为确保数据的定量化应用,国际航天遥感大国始终围绕定标技术开展研究,定标精度不断提高。在经历数十年发展之后,受传统的遥感载荷定标系统设计以及地面辐射校正技术理论极限的制约,目前遥感卫星辐射定标停留在太阳反射谱段2%,红外谱段0.2 K的不确定性水平,其精度难以继续提高。进入21世纪,气候变化问题成为全球关注的热点,全球气候变化研究对遥感卫星辐射测量精度提出了前所未有的要求。ASIC³（Achieving Satellite Instrument Calibration for Climate Change）报告指出,为了有效检测全球气候变化信号,准确预测气候变化,遥感卫星观测必须长期保持在太阳反射谱段0.3%、红外谱段0.1 K,太阳总辐射0.01%的不确定性水平。为了迎接这一挑战,欧洲和美国相继提出了CLARREO计划和TRUTHS计划,试图通过发射具有超高辐射测量精度的基准卫星,在监测气候变化信号的同时,标定其他遥感卫星,提升全球遥感卫星整体定标精度。同期,中国也提出了空间辐射测量基准技术的概念,并在“十二五”和“十三五”,通过国家高技术研究发展计划和国家重点研发计划持续支持星上相变固定点黑体、空间低温辐射计等尖端技术的研发,进而逐渐形成发射空间辐射测量基准卫星的路线图。从目前发展态势上看,中国有可能成为第一个建立空间辐射测量基准的国家,率先实现卫星平台辐射观测直接向国际单位（SI）的溯源。     

点云深度学习基准数据集

为推进深度学习方法在点云配准、语义分割、实例分割等领域的发展,武汉大学联合国内外多家高等院校和研究机构发布了包含多类型场景的地面站点云配准基准数据集WHU-TLS和包含语义、实例的城市级车载点云基准数据集WHU-MLS.其中,WHU-TLS基准数据集涵盖了地铁站、高铁站、山地、公园、校园、住宅、河岸、文化遗产建筑、地下...     

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Limits on the validity of infinite length assumptions for modelling shallow landslides

The infinite slope method is widely used as the geotechnical component of geomorphic and landscape evolution models. Its assumption that shallow landslides are infinitely long (in a downslope direction) is usually considered valid for natural landslides on the basis that they are generally long relative to their depth. However, this is rarely justified, because the critical length/depth (L/H) ratio below which edge effects become important is unknown. We establish this critical L/H ratio by benchmarking infinite slope stability predictions against finite element predictions for a set of synthetic two‐dimensional slopes, assuming that the difference between the predictions is due to error in the infinite slope method. We test the infinite slope method for six different L/H ratios to find the critical ratio at which its predictions fall within 5% of those from the finite element method. We repeat these tests for 5000 synthetic slopes with a range of failure plane depths, pore water pressures, friction angles, soil cohesions, soil unit weights and slope angles characteristic of natural slopes. We find that: (1) infinite slope stability predictions are consistently too conservative for small L/H ratios; (2) the predictions always converge to within 5% of the finite element benchmarks by a L/H ratio of 25 (i.e. the infinite slope assumption is reasonable for landslides 25 times longer than they are deep); but (3) they can converge at much lower ratios depending on slope properties, particularly for low cohesion soils. The implication for catchment scale stability models is that the infinite length assumption is reasonable if their grid resolution is coarse (e.g. >25 m). However, it may also be valid even at much finer grid resolutions (e.g. 1 m), because spatial organization in the predicted pore water pressure field reduces the probability of short landslides and minimizes the risk that predicted landslides will have L/H ratios less than 25. Copyright © 2012 John Wiley & Sons, Ltd.     

地铁施工中广州中信广场沉降监测

地铁施工中,高层建筑物都存在一定程度的下沉;结合中信广场的场地条件,介绍了在地铁施工期间的沉降监测实施方法,对沉降监测数据进行了分析,并得出施工阶段沉降变化的规律。其结果对保证建筑物的安全和保障地铁施工具有重要意义。     

我国绝对重力观测技术应用研究与展望

简要介绍了近年来运用高精度绝对重力仪,开展和建立我国2-5×10-8ms-2精度的绝对重力基准和绝对重力网工作;回顾了近年来中国学者利用绝对重力观测技术在地壳运动、地震监测与预报及地球动力学等研究方面所取得的成就;并探讨了未来进一步的应用前景.