Efficient regionalization techniques for socio‐economic geographical units using minimum spanning trees     

R. M. AssunÇão  M. C. Neves  C. Da Costa Freitas 《International journal of geographical information science》2013,27(7):797-811

Regionalization is a classification procedure applied to spatial objects with an areal representation, which groups them into homogeneous contiguous regions. This paper presents an efficient method for regionalization. The first step creates a connectivity graph that captures the neighbourhood relationship between the spatial objects. The cost of each edge in the graph is inversely proportional to the similarity between the regions it joins. We summarize the neighbourhood structure by a minimum spanning tree (MST), which is a connected tree with no circuits. We partition the MST by successive removal of edges that link dissimilar regions. The result is the division of the spatial objects into connected regions that have maximum internal homogeneity. Since the MST partitioning problem is NP‐hard, we propose a heuristic to speed up the tree partitioning significantly. Our results show that our proposed method combines performance and quality, and it is a good alternative to other regionalization methods found in the literature.  相似文献   

基于Surpac的乌山铜钼矿模型优化研究     

许国伟  高占义  王泽军 《西部资源》2013,(3):186-189

利用矿业软件Surpac,收集矿山在开采过程中的生产勘探数据和南矿段补勘所采集的钻孔资料,更新了地质数据库;对乌山铜钼矿矿床模型进行了优化研究;为边际品位指标优化提供了地质资源基础;同时也作为储量估算和境界圈定的依据。  相似文献   

SHORT COMMUNICATION DYNAMIC HEADSPACE ANALYSIS:OPTIMIZATION OF TITRATION BY EXPERIMENTAL DESIGN     

THIERRYTALOU  LUCRIGAL  ANTOINEGASET 《地理学报(英文版)》1988,(Z1)

The dynamic headspace titration of the volatile constituents of the black truffle(Tuber Melanosporum)isplanned to be carried out with the new gas chromatographic device DCI using Tenax trapping.In thispaper the necessary optimization of the experimental factors which influence the desorption of thevolatiles from the sample and the adsorption on the trap is carried out by experimental design.The studyof the isoresponse curves makes it possible to determine the optimum conditions for a rapid titration ofhighest sensitivity and reproducibility,avoiding water trapping.  相似文献   

COMPARISON OF TWO SCREENING METHODS FOR THE DETECTION OF VOLATILE ORGANIC COMPOUNDS IN GROUND WATER     

R.RAJAGOPAL PING-CHI LI Jessup Hall  Department of Geography  The University of Iow  Iowa City  IA  U.S.A. 《地理学报(英文版)》1991,(3)

It is shown that the presence of 31-35 commonly measured volatile organic compounds(VOCs)inground water can be detected with small error rates by using screening methods which analyze for a subsetof such VOCs.A study of selected data sets indicates that analytical determinations of only from twoto eight VOCs will suffice to detect 95% of all VOC hits.It is also shown that a serially optimal algorithmfor selecting the VOCs for screening is very nearly as accurate as a globally optimal algorithm and mucheasier to implement.These conclusions are supported by empirical evidence from two drinking-water datasets and one hazardous waste site data set.Additional research areas are also outlined.  相似文献   

SHORT COMMUNICATION A PROGRAM FOR THE SIMULTANEOUS POTENTIOMETRIC DETERMINATION OF PROTONATION CONSTANTS AND ELECTRODE CALIBRATION PARAMETERS     

J.J.BAEZA  G.RAMIS  C.MONGAY 《地理学报(英文版)》1988,(Z1)

A program for the potentiometric determination of the protonation constants of mononuclear polyproticsubstances is described.A maximum of twelve parameters can be determined simultaneously,includingup to six protonation constants,four electrode calibration parameters,the protolysis constant of thesolvent and the titrant concentration.Optimization is carried out by using the non-simplifiedNewton-Raphson method,which is potentiated by the Marquardt algorithm and a distance speeding-upcoefficient.A direct search method is also used to improve the initial set of values.Variances arecalculated very accurately,since the real Hessian function is used.Statistical weights and ionic strengthcorrections are also considered,The program has been tested by using simulated titration curves ofpolyprotic acids with close constants.  相似文献   

Groundwater modelling as a tool for the European Water Framework Directive (WFD) application: The Llobregat case   总被引：4，自引：0，他引：4  

E. Vázquez-Suñé  E. Abarca  B. Capino  M. Pool  F. Batlle  X. Ibáñez 《Physics and Chemistry of the Earth》2006,31(17):1015-1029

  相似文献   

Pump-and-treat optimization using analytic element method flow models     

L. Shawn Matott  Alan J. Rabideau  James R. Craig 《Advances in water resources》2006

Plume containment using pump-and-treat (PAT) technology continues to be a popular remediation technique for sites with extensive groundwater contamination. As such, optimization of PAT systems, where cost is minimized subject to various remediation constraints, is the focus of an important and growing body of research. While previous pump-and-treat optimization (PATO) studies have used discretized (finite element or finite difference) flow models, the present study examines the use of analytic element method (AEM) flow models. In a series of numerical experiments, two PATO problems adapted from the literature are optimized using a multi-algorithmic optimization software package coupled with an AEM flow model. The experiments apply several different optimization algorithms and explore the use of various pump-and-treat cost and constraint formulations. The results demonstrate that AEM models can be used to optimize the number, locations and pumping rates of wells in a pump-and-treat containment system. Furthermore, the results illustrate that a total outflux constraint placed along the plume boundary can be used to enforce plume containment. Such constraints are shown to be efficient and reliable alternatives to conventional particle tracking and gradient control techniques. Finally, the particle swarm optimization (PSO) technique is identified as an effective algorithm for solving pump-and-treat optimization problems. A parallel version of the PSO algorithm is shown to have linear speedup, suggesting that the algorithm is suitable for application to problems that are computationally demanding and involve large numbers of wells.  相似文献   

Grey fuzzy optimization model for water quality management of a river system   总被引：2，自引：0，他引：2  

Subhankar Karmakar  P.P. Mujumdar 《Advances in water resources》2006

A grey fuzzy optimization model is developed for water quality management of river system to address uncertainty involved in fixing the membership functions for different goals of Pollution Control Agency (PCA) and dischargers. The present model, Grey Fuzzy Waste Load Allocation Model (GFWLAM), has the capability to incorporate the conflicting goals of PCA and dischargers in a deterministic framework. The imprecision associated with specifying the water quality criteria and fractional removal levels are modeled in a fuzzy mathematical framework. To address the imprecision in fixing the lower and upper bounds of membership functions, the membership functions themselves are treated as fuzzy in the model and the membership parameters are expressed as interval grey numbers, a closed and bounded interval with known lower and upper bounds but unknown distribution information. The model provides flexibility for PCA and dischargers to specify their aspirations independently, as the membership parameters for different membership functions, specified for different imprecise goals are interval grey numbers in place of a deterministic real number. In the final solution optimal fractional removal levels of the pollutants are obtained in the form of interval grey numbers. This enhances the flexibility and applicability in decision-making, as the decision-maker gets a range of optimal solutions for fixing the final decision scheme considering technical and economic feasibility of the pollutant treatment levels. Application of the GFWLAM is illustrated with case study of the Tunga–Bhadra river system in India.  相似文献   

新一代省级农业气象预报系统通用统计预报模型的设计与实现     

邹春辉陈怀亮  张雪芬 《河南气象》2005,(2):40-42

统计预报方法是农业气象预报业务中常用的一种方法。在“新一代农业气象预报系统”中，系统设计了一种通用统计预报模型构建方法，可用于作物产量预报、农业气象灾害预报等农气预报业务。本文主要介绍了通用预报模型的设计原理、实现方法及应用试验结果等。  相似文献   

Mapping groundwater quality in the Netherlands   总被引：4，自引：0，他引：4  

Edzer J. Pebesma  J. W. de Kwaadsteniet 《Journal of Hydrology》1997,200(1-4):364-386

Maps of 25 groundwater quality variables were obtained by estimating 4 km × 4 km block median concentrations. Estimates were presented as approximate 95% confidence intervals related to four concentration levels mostly obtained from critical levels for human consumption. These maps were based on measurements from 425 monitoring sites of national and provincial groundwater quality monitoring networks. The estimation procedure was based on a stratification by soil type and land use. Within each soil-land use category, measurements were interpolated. Spatial dependence between measurements and regional differences in mean level were taken into account. Stratification turned out to be essential: no or partial stratification (using either soil type or land use) results in essentially different maps. The effect of monitoring network density was studied by leaving out the 173 monitoring sites of the provincial monitoring networks. Important changes in resulting maps were assigned to loss of information on short-distance variation, as well as loss of location-specific information. For 12 variables, maps of changes in groundwater quality were made by spatial interpolation of short-term predictions calculated for each well screen from time series of yearly measurements over 5–7 years, using a simple regression model for variation over time and taking location-specific time-prediction uncertainties into account.

From a policy point of view, the resulting maps can be used either for quantifying diffuse groundwater contamination and location-specific background concentrations (in order to assist local contamination assessment) or for input and validation of policy supporting regional or national groundwater quality models. The maps can be considered as a translation of point information obtained from the monitoring networks into information on spatial units, the size of which is used in regional groundwater models. The maps enable location-specific network optimization. In general, the maps give little reason for reducing the monitoring network density (wide confidence intervals).  相似文献