A Simulated Annealing-Based Algorithm to Locate Additional Drillholes for Maximizing the Realistic Value of Information

Locating additional drillholes based on information gathered from the initial drilling is a very difficult decision-making step in the process of detailed explorations. The most appropriate locations for additional drillholes are those wherein the information gathered from drilling has more value compared to that from other locations. From among the common methods proposed in information systems for measuring the information value, use of the “realistic value” is a very practical one. The realistic value of information is derived from measuring the differences in the decision makers’ performances when provided with different information sets. On this basis, a mathematical model has been proposed in this paper for optimal location of additional drillholes where the information gathered from drillholes has the highest possible value. Due to the combinatorial nature of this model, use has been made of a simulated annealing-based algorithm for its solution. The proposed model has been applied in Sungun copper deposit for locating additional drillholes; results have revealed that the model is valid.     

Modal Choice in the Pittsburgh Metropolitan Statistical Area: An Exploratory Data Analysis

Journey-to-work mode choice is intertwined with ideological and pragmatic issues. This article reexamines such issues using socioeconomic data from the decennial census and American Community Survey (ACS). It investigates the structure of variables with exploratory data analysis (EDA) because this technique advises the formation of hypotheses and the specification of cause and effect. Traditional EDA reveals the nonnormal structure of raw data, mapping illustrates associations between transit and income, and both methods suggest the presence of a transit-by-choice population among affluent metropolitan residents. The results yield three hypotheses concerning propensity to use transit that have previously received little attention.     

Statistical discrimination of foreshocks from other earthquake clusters

When earthquake activity begins, it may be a foreshock sequence to a larger earthquake, a swarm, or a simple main-shock-aftershock sequence. This paper is concerned with the conditional probability that it will be foreshock activity of a later larger earthquake, depending on the occurrence pattern of some early events in the sequence. The earthquake catalogue of the Japan Meteorological Agency (1926-1993, M_J≥4) is decomposed into a large number of clusters in time and space in order to compare statistical features of foreshocks with those of swarms and aftershocks. Using such a data set, Ogata, Utsu & Katsura (1995) revealed some discriminating features of foreshocks relative to the other types of clusters, for example the events' closer proximity in time and space, and a tendency towards chronologically increasing magnitudes, which encouraged us to construct models which forecast the probability of the earthquakes being foreshocks. Specifically, the probability is a function of the history of magnitude differences, spans between origin times and distances between epicentres within a cluster. For purposes of illustration, the models were fitted to the early part of the data (1926-1975) and the validity of the forecasting procedure was checked on data from the later period (1976-1993). Two procedures for evaluating the performance of the probability forecast are suggested. Furthermore, for the case where only a single event is available (i.e. either it is the first event in a cluster or an isolated event), we also forecast the probability of the event being a foreshock as a function of its geographic location. Then, the validity of the forecast is demonstrated in a similar manner. Finally, making use of the multi-element prediction formula, we show that the forecasting performance is enhanced by the joint use of the information in the location of the first event, and that in the subsequent interevent history in the cluster.     

A Statistical Analysis of the Theoretical Yield of Ethanol from Corn Starch

  This paper analyzes the Illinois State Variety Test results for total and extractable starch content in 708 samples of 401 commercial varieties of corn. It is shown that the normally distributed extractable starch content has the mean of 66.2% and the standard deviation of 1.13%. The corresponding maximum theoretical yield of ethanol is 0.364 kg EtOH/kg dry corn, and the standard deviation is 0.007. In the ethanol industry units, this yield translates to 2.64 gal EtOH/nominal wet bushel, and the standard deviation is 0.05 gal/bu. The U.S. ethanol industry consistently has inflated its ethanol yields by counting 5 volume percent of # 14 gasoline denaturant (8% of energy content) as ethanol. Also, imports from Brazil and higher alcohols seem to have been counted as U.S. ethanol. The usually accepted USDA estimate of mean ethanol yield in the U.S., 2.682 gal EtOH/bu, is one standard deviation above the rigorous statistical estimate in this paper.

Statistical comparison of palaeomagnetic directional records from lake sediments

Summary. This paper presents three statistical methods for testing the reproducibility or compatibility of palaeomagnetic directional records in undated cores of sediment. These methods are based on: (a) the intrinsic equations (curvature and torsion as functions of arc-length) of the curve defining changes in direction; (b) an F -test derived from multiple linear regression theory and (c) the construction and comparison of confidence bands. All methods utilize a projection of palaeomagnetic unit vectors on to the tangent plane to their mean direction. Since preliminary alignment to a common depth scale is necessary both for method (b) and for subsequent pooling of data, some theoretical results are presented for this problem, allowing for the possibility of missing segments in either core. Methods (b) and (c) are applied to two cores from Loch Lomond, Scotland. Both methods show that, after suitable relative rotation and alignment, these palaeomagnetic directional records are indeed compatible, demonstrating that the Loch Lomond sediments can provide reliable palaeosecular variation data of igh quality.     

Statistical analysis of drainage density from digital terrain data

Drainage density (D_d), defined as the total length of channels per unit area, is a fundamental property of natural terrain that reflects local climate, relief, geology, and other factors. Accurate measurement of D_d is important for numerous geomorphic and hydrologic applications, yet it is a surprisingly difficult quantity to measure, particularly over large areas. Here, we develop a consistent and efficient method for generating maps of D_d using digital terrain data. The method relies on (i) measuring hillslope flow path distance at every unchanneled site within a basin, and (ii) analyzing this field as a random space function. As a consequence, we measure not only its mean (which is half the inverse of the traditional definition of drainage density) but also its variance, higher moments, and spatial correlation structure. This yields a theoretically sound tool for estimating spatial variability of drainage density. Averaging length-to-channel over an appropriate spatial scale also makes it possible to derive continuous maps of D_d and its spatial variations. We show that the autocorrelation length scale provides a natural and objective choice for spatial averaging. This mapping technique is applied to a region of highly variable D_d in the northern Apennines, Italy. We show that the method is capable of revealing large-scale patterns of variation in D_d that are correlated with lithology and relief. The method provides a new and more general way to quantitatively define and measure D_d, to test geomorphic models, and to incorporate D_d variations into regional-scale hydrologic models.     

A Method for the Exploratory Analysis of Airline Networks

The airline industry in the United States has experienced significant changes in the spatial configuration of networks since the Airline Deregulation Act of 1978. Attempts have been made to study the structure of the hub-and-spoke network in the airline industry, but no efficient methodology has been available. This paper describes an exploratory approach to analyzing the spatial configuration of airline networks. Flight frequencies and numbers of passengers from published schedules of six U.S. domestic airlines (American, Continental, Delta, Northwest, United, and USAir) are used in this study. The analytic components in the exploratory system include the examination of network connectivity and network autocorrelation in a dynamic mapping environment. The results of the analyses show both the overall spatial patterns of airline networks and the hierarchical hubbing structures.     

Exploratory analysis of paleoecological data using the program CanoDraw

This paper attempts to persuade the reader that methods of direct gradient analysis may serve as a basis for more detailed exploration of the data and that these exploration methods can be also used for checking the appropriateness of the assumptions of the applied ordination method. Generalized linear models and generalized loess smoothing together with several ways of data presentation are used to explore a sample data set.     

河口河槽季节性冲淤变化及其对河流来水来沙响应的统计分析——以长江口南槽为例

利用长江口南槽1989年12个月的实测地形图和大通站相应的水沙资料,采用GIS技术和数理统计技术分析了南槽的地形变化与河流来水来沙的关系。结果表明:南槽水深与大通站各月平均流量、输沙率和含沙量之间有明显的相关性,说明河口冲淤对流域水沙变化有敏感响应;河槽的响应具有1~1.5月的滞后性。     

《地域研究与开发》2000～2006年载文统计分析

用文献计量法对《地域研究与开发》2000～2006年的年载文量,载文的栏目分布,作者的职称、学位、年龄、所在区域和工作单位分布等方面的情况进行了统计分析,揭示了该刊物栏目分布的一些特征、作者的情况和《地域研究与开发》办刊特色及其在地理科学研究中的地位和作用,使读者加深对本刊的了解,也为今后进一步提高该期刊的质量及促进学术交流提供参考.     

探索性空间分析及其与GIS集成模式探讨

探索性空间分析基于让数据说话的理念,可以避免野值或非典型观测值的误导。在对探索性空间分析的基本原理和概念界定的基础上,探讨交互式和动态空间数据分析、地学可视化及可视化空间分布、确认性空间分析、空间数据挖掘等探索性空间分析的主要技术。由于统计分析软件和GIS的数据格式差异很大,直接将二者简单集成存在一定困难,因此切实可行的集成方式是采用对象连接和嵌入(OLE)技术,分别调用统计分析软件的探索性分析功能(或者函数)以及GIS的地图显示和空间分析功能,并进行必要开发,实现二者的集成。最后对探索性空间分析的发展方向进行展望。     

Statistical analysis of modern seed assemblages from the San Francisco Bay: applications for the reconstruction of paleo-salinity and paleo-tidal inundation

The feasibility of developing a seed calibration data set to infer environmental constraints was examined by studying modern seed and vegetation assemblages from 53 stations at three distinct tidal marshes within the San Francisco Bay (salt, brackish and freshwater). Pearson's correlation indicates autochthonous derivation of seeds at the marsh sites. Multivariate statistical analysis of the vegetation and seed data indicates discrete assemblages, which can be used as a proxy for modern salinity and tidal inundation within the estuary. Canonical discriminant analysis indicates that the vegetation and seed assemblages of the three marsh types are statistically distinct. Cluster analysis suggests that marsh vegetation is zoned at the mean higher high water mark at all the sites. The calibration set was then applied to stratigraphic seed data from the estuary to infer changes in paleo-salinity and -tidal inundation during the Holocene. The results of the calibration are compared to earlier reconstructions within the estuary. While the calibrated reconstruction broadly compares to previous reconstructions, a period of inferred lower salinity within the estuary between 3800–2000 cal yr B.P. is calibrated as brackish and not fresh by the calibration model.     

Statistical study of the occurrence of shallow earthquakes

Summary. The time—space-magnitude interaction of shallow earthquakes has been investigated for three catalogues: worldwide ( M ≥ 7.0), Southern and Northern California ( M ≥ 4.0) and Central California ( M ≥ 1.5). The earthquake sequences are considered as a multi-dimensional stochastic point process; the estimates of the parameters for a branching model of the seismic process are obtained by a maximum-likelihood procedure. After applying magnitude—time and magnitude—distance scaling, the pattern of relationship among earthquakes of different magnitude ranges is almost identical. The number of foreshocks diminishes as the magnitude difference between the main shock and the foreshocks increases, while the magnitude distribution of aftershocks has the opposite property. The strongest aftershocks are likely to occur at the beginning of the sequence; later they migrate away with velocities of the order of km/day. The sequences which are composed of smaller aftershocks last longer and there are indications that they remain essentially in the focal region. Foreshocks also appear to migrate, but in this case, toward the main shock. The rate of occurrence of dependent shocks increases as t ^-1 as the origin time of the main shock is approached, effectively making every earthquake a multi-shock event. This interaction of earthquakes was modelled by a Monte-Carlo simulation technique. The statistical inversion of simulated catalogues was undertaken to derive the information we would be able to retrieve from actual data, as well as possible errors of estimates. The possibility of using these results as a tool for seismic risk prediction is discussed and evaluated.     

基于信息量模型的玉树地震次生地质灾害危险性评价

2010-04-14发生在青海省玉树的Ms7.1级地震引发了大量的地质灾害.基于GIS技术和信息量模型方法,以坡度、坡向、高程、坡形、地貌类型、断层距和地层岩性为评价因子,通过空间分析计算各因子的信息量,分析地质灾害在各因子中的空间分布特征,对各评价因子图层进行空间建模,将获取的信息量图划分为高度、中度、轻度三级危险区,通过遥感解译研究区实际滑坡分布,与危险性分布图叠加表明:本次研究得出的危险等级与实际的滑坡发生情况相吻合,为灾区重建提供参考依据.     

在探究性实验教学情境中培养地理实践力的尝试

地理实践力在课堂中是比较难落实的,而实验教学却能在室内的真实情境中通过设计实验、动手操作、观察记录、研究分析、成果发布和交流分享中提高学生的信息素养、问题意识和行动能力,从而能够应对现实问题,培养地理实践力的学科素养。