A review of geophysical methods used in archaeology

Geophysical methods have been used with increasing frequency in archaeology since 1946; aerial photography has been used since 1919. The geophysical methods that are most commonly used at present are electrical resistivity, magnetics, and ground-probing radar. Magnetic detectors, particularly when used in a gradient mode or with a continuously recording base station, are used at almost all sites where any geophysical methods are used. Portable, noncontacting electromagnetic soil-conductivity systems are also being increasingly used because of their very high rate of data acquisition. Less commonly used methods include self-potential (sometimes called spontaneous potential), microgravity, radiometric, thermal infrared imagery, and sonic or seismic techniques. Recent developments in image processing and graphic representation have contributed substantially to the archaeologist's ability to do “rescue archaeology,” that is, to carry out high-speed, nondestructive reconnaissance surveys for ancient human cultural evidence in advance of modern industrial development.     

数值流形方法中覆盖函数选用的建议

在数值流形方法中,常用的覆盖函数基并非是最佳选择。循着刚度矩阵的形成过程,分析了选用常用覆盖函数时,在非对角元上出现绝对值很大的元素之成因,且发现这会增加刚度矩阵的条件数,尤其是在用刚性弹簧约束位移的情况下,而这在数值流形方法中普遍而基本。建议采用局部化较好的覆盖函数,取代常用的关联于全局坐标的覆盖函数,可显著消除这一情况。建议方式简单明了,程序改动极小,对改善刚度矩阵性态却有很大作用。算例验证了这一建议的合理性,通过比较局部化的覆盖函数及全局性的覆盖函数所形成的刚度矩阵,表明前者形成了较小条件数的刚度矩阵。     

改进GM(1,1)模型在路基沉降预测中的应用

GM(1,1)模型是沉降预测中应用较为广泛的模型之一,在实际应用当中发现其预测效果有时候较差甚至完全失效。为此从传统GM(1,1)预测模型建模原理出发,分析存在的理论缺陷,指出在形成预测公式时规定 , 0.5为已知条件是不合理的,应当根据实际情况选用其他数据。通过引入平均斜率来计算 序列,并利用MATLAB程序进行数据处理,寻找最合适的 以及最佳维数区。某高速公路实测沉降数据计算表明,新方法有满意的拟合和预测效果,为提高建模精度提供了新的途径。     

Use of fully softened shear strength in slope stability analysis

Fully softened shear strength is an important empirical engineering concept for slope stability analyses of cuts in stiff clays and compacted embankments constructed of high-plasticity clays. This concept has been used to explain many first-time failures for which the back calculated shear strength is below the peak strength measured in the laboratory. A comprehensive review of case histories and laboratory studies related to fully softened shear strength was used to assess the application of this concept. The case history data were also used to provide guidelines on the soil types for which fully softened shear strength is appropriate, how and when this shear strength should be used in slope stability analysis, and how the fully softened failure envelope should be characterized. This paper contains specific guidelines on when and how the fully softened shear strength concept should be used in slope stability analyses.     

Analysis of subsurface magnetic features of the southeast of Al-Muwayh quadrangle,Saudi Arabia,using aeromagnetic data

Aeromagnetic data have been utilized to investigate the subsurface features of the southeast of Al-Muwayh quadrangle. Several techniques have been comprehensively used in an integrative way to reach the goals. Local phase and normalized standard deviation filters are used in this study as edge detectors, showing the possible occurrences of structural lineaments/faults in the quadrangle. Magnitude magnetic transform filters are used to produce anomalies that are closer to the true horizontal position of magnetic sources to enhance the interpretation. Among these transforms, a transform which has been used as edge detectors and the other two transforms are used to show the shallow and the shallowest magnetic sources within the study area. Tilt angle is mainly used to delineate the main magnetic contacts (faults), their locations, and their expected depths. The integration between these different filters show clearly the possible occurrences of edges (contacts/faults), the direction of these lineaments, the source locations of magnetic anomalies, the shallow and the shallowest causative targets, and the location and the depths of the main faults deduced from the tilt angle approach.     

相位激电测深在有色金属矿产勘查中的应用

激发极化方法一直是有色金属矿产勘查的主要手段,国内大多使用时间域激发极化方法,相位激发极化法应用较少。相位激电法采用选频测量,抗干扰能力相对较强,近些年在有色金属矿产勘查中一直使用相位激电测深方法,取得了较好的实际应用效果。在使用中,根据实际情况选用偶极-偶极或单极-偶极测量装置,其中偶极-偶极测量装置主要用于普查阶段,单极-偶极装置采用常规高密度电法的布极方式,主要用于详查阶段。这里以具有代表性的高阻高极化、低阻高极化矿体上的应用结果为例,说明偶极-偶极和单极-偶极装置相位激发极化测深的应用效果,以及在实际找矿工作中的作用。     

节理岩体中应力波传播规律研究的进展

讨论了位移不连续模型与特征值法结合的方法,对垂直于单一线性变形节理、多个平行线性变形节理、单一非线性变形节理,分别采用线性变形不连续模型、双曲线变形不连续模型(BB模型)进行的理论与相应的实验研究。用离散元程序UDEC,对上述问题进行数值模拟;用三维离散元程序3DEC,对节理岩体中三维波的传播进行的数值模拟。并用UDEC与有限差分程序AUTODYN-2D耦合,模拟爆炸过程及爆炸波在节理岩体中的传播。同时提出了几个有待研究的问题。     

Review and assessment of biotic variables and analytical methods used in estuarine inflow studies

Published and gray literature, and works in progress, were reviewed to identify biotic variables and analytical methods used in studying freshwater inflow needs of estuaries. Landings, CPUE, and other measures of single-species abundance are most often used, especially for shellfish and finfish. These efforts work best when biomass is used and lag times are allowed for recruitment, but neither method is always used, and most efforts have assumed that physical habitat availability is constant. Efforts employing habitat and community-level variables are used less often but more recent attempts are using dynamic as well as stationary definitions of habitat. Even stationary habitat methods have given less attention to tidal freshwater and brackish estuarine reaches, than to other reaches. Natural long-period climate cycles (El Ninõ Southern Oscillation; North Atlantic Multi-Decadal Oscillation) are not factored into most inflow studies. Three promising approaches are encouraged; a mixture of variables representing different levels of ecological organization should be used, the natural non-linear geometry of estuaries (especially tidal rivers) should be exploited to identify critical thresholds of inflow, and the validity of using instream flow methods to calculate estuarine requirements by proxy should be determined.     

区域水资源可持续利用系统评价的模糊对向传播神经网络模型

针对我国水资源可持续发展的评价问题,结合模糊对向传播神经网络分类灵活、算法简练的优点,本文提出区域水资源系统可持续利用评价的模糊对向传播神经网络模型,对水资源可持续利用进行评价.文章采用随机模拟技术生成评价指标序列,并和其所属的评价等级值构建训练样本,基于模糊CP网络结构建立评价模型,并进行了实例应用.计算结果表明,模型合理,可操作性强,模型具有普适性,可用于区域水资源的可持续利用评价.     

Modelling pile capacity using Gaussian process regression

This paper investigates the potential of a Gaussian process (GP) regression approach to predict the load-bearing capacity of piles. Support vector machines (SVM) and empirical relations were used to compare the performance of the GP regression approach. The first dataset used in this study was derived from actual pile-driving records in cohesion-less soil. Out of a total of 94 pieces of data, 59 were used to train and the remaining 35 data were used to test the created models. A radial basis function and Pearson VII function kernels were used with both GP and SVM. The results from this dataset indicate improved performance by GP regression in comparison to SVM and empirical relations. To validate the performance of the GP regression approach, another dataset consisting of 38 pieces of data was considered. The results from this dataset also suggest improved performance by the Pearson VII function kernel-based GP regression modelling approach in comparison to SVM.     

岩石地球化学图解辅助分析软件的关键问题及解决方法

岩石地球化学图解是目前岩石地球化学研究工作中常用的有效手段,其对岩石分类、岩石和矿床的成因判别、构造环境判别和地质演化历史等方面的研究有重要的意义。通过对目前国内外常用的岩石地球化学图解辅助分析软件的分析,发现此类软件亟待解决的关键问题,即收录图解的种类和数量有限且不易扩展、使用过程自动化程度不高和软件独立性不强等。在收集整理了岩石地球化学领域8个大类、232幅图解的基础上,提出采用后缀表达式实现投点过程自动化和使用XML定义、扩展图解,按照岩石地球化学领域专家的工作流程,设计实现岩石地球化学图解成图、投点和计算软件以及CIPW等岩石地球化学常用计算方法。     

基于GIS的景观空间格局地形分布及生态效应的研究——以黑龙江省尚志市帽儿山地区为例

采用地形位指数描述区域地形差异,并利用无量纲的分布指数对景观组分空间分布特征进行定量分析;通过地形差异揭示景观空间格局分布规律,并对各景观要素定量赋值,通过生态效应模型研究土地利用综合生态效应。结果表明：自然景观主导区域景观格局,人为景观次之,半自然景观则明显处于支配地位;各景观组分在地形位梯度上的分布格局表现出显著分化,低段区域上各景观组分竞争激烈,分布相对集中,高段区域,限制了部分景观的生存发展,景观组分相对单一;生态环境质量好的区域,自然景观为主体;生态环境质量中等的区域,处于自然景观和人为景观的过渡地带;生态环境差的区域,以人为景观为主体。     

污染物的固化/安定化处理的种类和研究应用现状

污染物的固化／安定化技术处理可归纳为6大类,即基于水泥的固化技术、基于石灰的固化技术、矿物吸附技术、热固技术、热塑技术和玻璃化技术等。其中有机聚合物固化剂（热固、热塑材料）一般用于处理固态有机污染物;玻璃化技术一般用于处理污染土、城市垃圾焚烧物和放射性物质。因无机胶结剂操作方便、成本低、能处理的无机污染物范围很广,因此使用频率较高（90％以上）,而有机胶结剂固化技术和废物玻璃化处理技术成本高,仅被用于特殊污染物的处理。     

基于地震数据构造曲率属性预测裂缝

为了有效预测岩层裂缝发育与分布,利用新疆准噶尔盆地南缘霍尔果斯背斜在纵弯变形作用下地震数据构造曲率属性进行了分析,并在此基础上进行了裂缝预测。具体方法是:利用petrel软件分析研究区的地震数据,追踪主要层面和断层并提取目标层面曲率和建立构造模型;考虑层面曲率对裂缝预测的局限性,通过“蚂蚁追踪”进一步提取目标层三维曲率属性而提取裂缝分布规律,将提取的裂缝与构造模型相结合。实例表明,上述方法可以简单、高效、全面地预测裂缝发育与分布,因此具有较强的实用性。     

Multivariate mixing and mass balance (M3) calculations,a new tool for decoding hydrogeochemical information

To support and help hydrochemical evaluation a multivariate mathematical tool named M3 (Multivariate Mixing and Mass balance calculations) has been created within the Äspö Hard Rock Laboratory Research Programme. The computer code can be used to trace the origin of the groundwater and calculate the mixing portions and mass balances from ambiguous groundwater data. Groundwater composition data used traditionally to describe the reactions taking place in the bedrock can now be used to trace the effect from present and past groundwater flow with increased accuracy. The M3 model consists of the following 3 steps:

• •Multivariate analysis, called Principal Component Analysis (PCA) is used to summarise the information from the data set. The summarised information shown in the PCA plots is used for finding relationships, patterns, extreme waters and for further M3 modelling.
• •From the PCA plot mixing calculations are used to calculate the effect of the groundwater mixing on the obtained groundwater composition. This so-called ideal mixing model is used to calculate the mixing proportions given in %, for all the groundwater samples.
• •The final step in M3 calculations is the mass balance calculations. Deviations from the ideal mixing model are used to trace the sources and sinks of elements, given in mg/l, which can be due to mass balance reactions.

The tested margin of error of the model is ±10% for the Äspö site data, but depends on the data to be modelled. A mixing portion of less than 10% is regarded as under the detection limit of the model and such calculations are therefore uncertain. This method can be used to trace the origin and calculate the mixing portions and effects from the reactions on the observed groundwater composition with a higher resolution and convenience compared to many standard methods.     

Impact of climate change on the wheat-growing season over Iran

The objective of this paper is to derive and analyze the present and future climate projections over the region of wheat production over Iran. In addition, the projected future climate fluctuation results will be used to assist the maximum performance of wheat and to be used as the main basis for planning changes in the farming calendar in Iran. Observed climate (temperature and degree day) changes during the period (1951–2009) will be discussed. Projected future changes up to 2100 based on the MAGICC/SCENGEN 5.3 compound model was utilized. Furthermore, 18 scenarios were used to derive a single GCM model referred to as the United Kingdom Hadley Center Global Environment Model, which will be used to select the worst, best, and average scenario.     

植物粗糙度对明渠水流阻力影响的试验研究

以水力半径分割法的思想为出发点,建立了新的明渠阻力分割计算关系式,在此基础上分析研究明渠中处于淹没状态下床面柔性植物对水流阻力的影响。采用多普勒流速仪测量边壁附近的流速,用间接法中的流速测量法测量边界上的切应力,用棕榈毛作为植物的模拟材料。以植物粗糙度表示植物阻力,用植物高度、密度的函数表示床面粗糙度,在植物高度和密度变化的情况下,进行水槽试验。经过对试验数据分析,发现植物粗糙度随植物高度、密度的增加而增加,且植物粗糙度越大时,在数值上越接近植物高度。拟合粗糙度与植物高度和密度的经验关系式,进而得出了植物阻力的计算式。     

Interpretation of some magnetic bodies using neural networks inversion

Magnetic surveys have been used for mineral exploration where different data processing techniques were used to derive the parameters of causative targets. In this respect, the neural network (NN) technique was used to estimate the magnetic causative target parameters. Examples of NN inversion have been tested on synthetic examples where the NN was trained well using forward models of the vertical magnetic effect of a vertical sheet and a horizontal circular cylinder. Specifically, modular neural network (MNN) inversion has been used for the parameter estimation of the causative targets, where the sigmoid function was used as the activation function. The effect of random noise and the error estimation of the horizontal location have been analyzed. When NN is applied to real data, it estimates successfully the parameters of the causative targets such as burial depths, magnetic constants, and angle of polarization. Hilbert transform has been used to locate the source origin, which is important for the NN inversion. This approach has more advantages than the conventional data inversions in terms of its efficiency and flexibility. It also gives fast solutions. The MNN approach has been applied to the Kursk and Manjampalli anomalies, where the results were shown to be in good agreement with the other techniques published in the literature.     

岩质边坡楔形体稳定模糊随机可靠性研究

在统计矩点估计法和模糊随机理论的基础上,提出了楔形体模糊随机可靠性分析改进的模糊点估计法,将楔形体稳定极限状态方程由模糊随机集向普通随机集转化,首先采用Bayes推断方法求解小样本条件下结构面力学参数的概率分布函数,用正态模糊数对随机变量进行模糊随机化处理,然后利用模糊点估计法求解楔形体的可靠度指标。算例分析结果表明,该法使用简便,结果可靠,更能客观地反映楔形体的真实状态,从而为工程决策提供依据。     

Visualising data distributions with kernel density estimation and reduced chi-squared statistic

The application of frequency distribution statistics to data provides objective means to assess the nature of the data distribution and viability of numerical models that are used to visualize and interpret data. Two commonly used tools are the kernel density estimation and reduced chi-squared statistic used in combination with a weighted mean. Due to the wide applicability of these tools, we present a Java-based computer application called KDX to facilitate the visualization of data and the utilization of these numerical tools.