An Approach to Spectral Discrimination of Rocks Using ASAI and Rough Sets

Field data of outcrop spectrums provide important basis for modeling of hyper-spectral remote sensing aiming at mineral prospecting. We make an approach to the application of rough set theory in spectral discriminiation of rocks. We build a decision table with an adequate number of samples (out-crops) of known rock type (the universe), of which the conditional atributes are discretized “area spectrum absorption indexes“ (ASAI) corresponding to wavelength intervals, and the decision atribute is rock type. We search to obtain the exhaustive set of reducts of the table, each of which will serve as a variable number of deduction rules. Suppose we have n (usually a very big number) rules in total and there are m types of rocks in our universe, for any unknown sample, we judge its rock type by each of those rules. An unknown sample may be recognized as a different type by different rules because it is out-side our universe, and we accept the most frequent judgment result and ignore the other m-1 types of results. Our ASAI is an improvement upon the traditional spectrum absorption index (SAI), better applicable to field spectrums: given a spectrum curve and a wavelength interval, we take the average reflectance within the interval as a base line and let ASAI=αbelow/(αabove αbelow), where αbelow and αabove stand for total areas, bounded by the curve, the base line and the borders of the intervalbelow and above the base line respectively. With the equipments of FieldSpectr Fr (made by ASD Co., US), we collected data from Baiya gold deposit, Yunnan, and applied the above method to discriminate altered rocks as an experiment. The results show satisfactory performance of the method.     

基于集对分析的水资源变化趋势的统计预测

根据集对分析(SPA)的原理和方法，对水资源变化趋势的预测进行了研究。利用前期的预测因子进行计算，可以使集对分析具有预测功能。通过反复调整预测因子各区段的分界值，可以使水资源要素计算等级和实际等级的历史拟合率达到最大，其结果是比较好的。这是对水资源变化趋势的预测研究的一种新尝试。     

基于集对分析和模糊集合论的水体营养化评价模型的应用研究

尝试在水环境评价领域引入并应用集对分析和模糊集合论，结合水体营养化等水环境评价中模式识别、等级评价问题的实际应用，将相关的概念和理论进行拓广，定义了广义联系熵和广义相对隶属度。分别建立了基于集对分析的水体营养化评价一级模型和基于集对分析一模糊集合论的水体营养化评价二级模型。我国12个有代表性的湖库营养化程度评价的应用实例表明：所建模型的评价结果与调查结果相符，与单一模糊模式识别结果基本相符；二级模型与一级模型和单一模糊模式相比，评价结果相对全面，更符合用水障碍调查结果的实际情况；而且从广义联系熵判断，二级模型的广义联系熵较一级模型和单一模糊模式大一些，即更好地反映了待评价水样与评价标准两个集合的确定不确定关系和联系程度，从而在一定程度上验证了所建模型的有效性和简便性。文中所用理论方法和所建模型也可推广应用于其他领域。     

Holocene annual mean temperature changes in Estonia and their relationship to solar insolation and atmospheric circulation patterns

We reconstructed annual mean temperature (T_ann) trends from three radiocarbon-dated Holocene pollen stratigraphies from lake sediments in Estonia, northern Europe. The reconstructions were carried out using a North-European pollen-climate calibration model based on weighted averaging partial least-squares regression. The cross-validated prediction error of the model is 0.89°C and the coefficient of determination between observed modern T_ann values and those predicted by the model is 0.88. In the reconstruction, the Holocene thermal maximum (HTM) is distinguishable at 8000-4500 cal yr B.P., with the expansion of thermophilous tree species and T_ann on average 2.5°C higher than at present. The pollen-stratigraphical data reflect progressively warmer and drier summers during the HTM. Analogously with the modern decadal-scale climatic variability in North Europe, we interpret this as an indication of increasing climatic continentality due to the intensification of anticyclonic circulation and meridional air flow. Post-HTM cooling started abruptly at around 4500 cal yr B.P. All three reconstructions show a transient (ca. 300 years) cooling of 1.5-2.0°C at 8600-8000 cal yr B.P. We tentatively correlate this cold event with the North-Atlantic “8.2 ka event” at 8400-8000 cal yr B.P. Provided that the 8.2 ka event was caused by freshening of the North-Atlantic surface water, our data provide evidence of the climatic and vegetational responsiveness of the boundary of the temperate and boreal zones to the weakening of the North-Atlantic thermohaline circulation and the zonal energy transport over Europe. No other cold events of comparable magnitude are indicated during the last 8000 years.     

Prediction of Sandstone Porosity Through Quantitative Estimation of its Mechanical Compaction During Lithogenesis (Bibieybat Field, South Caspian Basin)

In this paper a new and easy quantitative approach based on an exponential decrease in intergranular volume as a function of effective stress and incorporated with fuzzy mathematics is suggested for evaluation of the lower limit of sandstones porosity. Furthermore, the comparison of predicted values of sandstones porosity with factual ones allow drawing some conclusions regarding succession of compaction and cementation processes taking place through burial history of rocks.     

粗集在知识发现中的应用

介绍了粗集的基本概念,包括粗集的定义、“属性－值”系统、属性依赖与归约及粗集概念的若干推广,最后指出粗集理论在知识发现（KDD）中的一个可能应用途径。     

模糊逻辑理论在矿区勘探与解释中的应用

本文介绍了模糊逻辑理论及其在矿区勘探与解释中的应用,并给出了相应的计算公式及应用模糊逻辑理论预测某金矿远景区的计算实例。     

塔西南坳陷侏罗系的扇三角洲沉积

塔西南坳陷侏罗系广泛发育扇三角洲沉积。在论述沉积特征的基础上,确认本区的扇三角洲是一个典型的退积型层序。该层序三层结构明显,下部为扇三角洲平原,中部为扇三角洲前缘,上部为前扇三角洲。反映了该区在早中侏罗世时处于活动盆地边缘,湖水由浅变深,沉降速率大于沉积速率的特点。通常扇三角洲的形成受湖盆边界类型和源区距湖盆距离及古气候３个主要背景条件的约束,因此,本区的扇三角洲一般发育在源区距湖盆距离短,靠近山前植被不发育的地带。塔西南坳陷侏罗系生储盖组合发育齐全,湖相暗色泥岩为主要烃源岩,扇三角洲前缘砂体是较好的储集层,上白垩统和第三系膏泥岩则起着主要的封盖作用。本区侏罗系有着良好的油气勘探前景。     

Distribution of diatoms among intermittent ponds on the Atlantic Coastal Plain: development of a model to preduct drought periodicity from surface-sediment assemblages

Inferences of past climate from the fossil record in lakes rely on the accurate quantification of a relationship of fossilizing organisms to their environment. Whereas the relationship of diatoms to water chemistry parameters has been modeled in many systems, few studies adequately address the relationship of diatoms to physical properties, such as water depth or hydrology, that may be more directly tied to climate. We examined the composition of modern diatoms in surface sediments of 75 isolated ponds (mostly Carolina bays) of the Atlantic Coastal Plain to: (1) assess the influence of physical and chemical variables on the distribution of diatoms among ponds of the region, and (2) develop a model that predicts hydroperiod (a measure of pond permanence) from diatom assemblages. We constructed two hydroperiod calibration models: the first infers hydroperiod from the weighted-average optima and tolerances of taxa along the hydroperiod gradient, the second bases inferences on the hydroperiod estimates of compositionally similar samples. Both approaches incorporate a-priori and post-hoc tests of assumptions often inherent in the construction of transfer functions. Diatom assemblage composition had strong, approximately linear relationships to hydroperiod, water depth, and calcium concentration in non-metric multidimensional ordination space; effects of other variables, including pH, were non-linear or ambiguous. Overall, the assemblages reflected the dilute, acidic chemical characteristics of bays. The assemblages contained differing abundances of euterrestrial, benthic and planktonic taxa, depending on a pond's susceptibility to drying. A weighted-averaging regression model based on taxon-specific hydroperiod optima generated adequate, unbiased hydroperiod inferences from diatom species composition (r² = 0.81). This model may be used to infer past drought episodes from fossil diatom assemblages at appropriate sites on the Atlantic Coastal Plain.     

CHAOTIC OUTPUT OF SST FLUCTUATION STOCHASTIC MODEL WITH GIVEN PARAMETERS

Starting from the Saltzman's air-sea stochastic climatic model, we have derived a langevin-type equation describing SST fluctuation and the related pokker-Plank expression, which were then numerically solved with parameters given, yielding the probability density curve P(x, t) of multiple bifurcations, with the Cantor set of images given in phase space of P(x, t) and P(x, t+τ), thereby indicating that chaotic output comes from the random system under the conditions of the above parameters.