略谈我国矿产资源的保护

本文根据矿产资源开发利用的阶段性，阐述了其保护内容，并在探讨保护理论的基础上，提出了我国矿产资源的保护模式及重点，以及构造矿产资源保护体系的设想。     

GIS辅助下的基于数据挖掘的林型遥感分类方法研究

在植被分类领域,各类植被光谱特征非常相近,纹理特征比较单一,并且受物候影响较大,使得影像上林地信息的分类识别的成为一个较复杂的过程。本文利用GIS平台构建由影像、DEM等组成的多元空间数据库,将数据挖掘的方法引入林型遥感分类中,充分利用了现有的空间数据资源,减少了同物异谱、异物同谱对林型遥感分类的影响,增强了分类知识获取的自动化和智能化程度。实验结果表明,该方法具有简化知识获取过程和提高分类精度等优点。     

MODIS-NDVI-based mapping of the length of the growing season in northern Fennoscandia

Northern Fennoscandia is an ecologically heterogeneous region in the arctic/alpine-boreal transition area. Phenology data on birch from 13 stations and 16-day MODIS-NDVI composite satellite data with 250 m resolution for the period 2000 to 2006 were used to map the growing season. A new combined pixel-specific NDVI threshold and decision rule-based mapping method was developed to determine the onset and end of the growing season. A moderately high correlation was found between NDVI data and birch phenology data. The earliest onset of the growing season is found in the narrow strip of lowland between the mountains and the sea along the coast of northern Norway. The onset follows a clear gradient from lowland to mountain corresponding to the decreasing temperature gradient. In autumn, the yellowing of the vegetation shows a more heterogeneous pattern. The length of the growing season is between 100 and 130 days in 55% of the study area.     

Mining significant crisp-fuzzy spatial association rules

Spatial association rule mining (SARM) is an important data mining task for understanding implicit and sophisticated interactions in spatial data. The usefulness of SARM results, represented as sets of rules, depends on their reliability: the abundance of rules, control over the risk of spurious rules, and accuracy of rule interestingness measure (RIM) values. This study presents crisp-fuzzy SARM, a novel SARM method that can enhance the reliability of resultant rules. The method firstly prunes dubious rules using statistically sound tests and crisp supports for the patterns involved, and then evaluates RIMs of accepted rules using fuzzy supports. For the RIM evaluation stage, the study also proposes a Gaussian-curve-based fuzzy data discretization model for SARM with improved design for spatial semantics. The proposed techniques were evaluated by both synthetic and real-world data. The synthetic data was generated with predesigned rules and RIM values, thus the reliability of SARM results could be confidently and quantitatively evaluated. The proposed techniques showed high efficacy in enhancing the reliability of SARM results in all three aspects. The abundance of resultant rules was improved by 50% or more compared with using conventional fuzzy SARM. Minimal risk of spurious rules was guaranteed by statistically sound tests. The probability that the entire result contained any spurious rules was below 1%. The RIM values also avoided large positive errors committed by crisp SARM, which typically exceeded 50% for representative RIMs. The real-world case study on New York City points of interest reconfirms the improved reliability of crisp-fuzzy SARM results, and demonstrates that such improvement is critical for practical spatial data analytics and decision support.     

基于大数据的城市服务业空间关联分析

信息技术与电商平台的发展,产生了各种各样的大数据。在城市服务业中,商家在电商平台上注册自己带有坐标的信息,构成了空间服务业的空间大数据源。首先建立限定距离阈值的空间关联规则数据模型,介绍该模型产生频繁项集和关联规则的方法与步骤。最后利用Python爬取糯米网南宁站的商家信息,用Apriori算法做出了10~1 000 m 6种距离阈值的空间关联规则和服务业空间频繁项集。     

Spatial co-location pattern mining of facility points-of-interest improved by network neighborhood and distance decay effects

The aim of mining spatial co-location patterns is to find the corresponding subsets of spatial features that have strong spatial correlation in the real world. This is an important technology for the extraction and comprehension of implicit knowledge in large spatial databases. However, existing methods of co-location mining consider events as taking place in a homogeneous and isotropic context in Euclidean space, whereas the physical movement in an urban space is usually constrained by a road network. Furthermore, previous works do not take the ‘distance decay effect’ of spatial interactions into account, which may reduce the effectiveness of the result. Here we propose an improved spatial co-location pattern mining method, including the network-constrained neighborhood and addition of a distance-decay function, to find the spatial dependence between network phenomena (e.g. urban facilities). The underlying idea is to utilize a model function in the interest measure calculation to weight the contribution of a co-location to the overall interest measure instance inversely proportional to the separation distance. Our approach was evaluated through extensive experiments using facility points-of-interest data sets. The results show that the network-constrained approach is a more effective method than the traditional one in network-structured space. The proposed approach can also be applied to other human activities (e.g. traffic accidents) constrained by a street network.     

大规模跨流域水库群供水优化调度规则

针对大规模跨流域供水水库群联合调度中调水、引水、供水三者之间的复杂性、动态性和不确定性的特点,在二层规划模型的基础上,应用博弈论原理,建立跨流域水库群供水调度规则的三层规划模型,提出调水规则、引水规则和供水规则相结合的跨流域水库群优化调度规则,从深层次揭示跨流域供水水库群之间的主从递阶层次的独立性及相互关联性;并应用基于免疫进化的粒子群算法对模型进行分层优化求解。以滦河下游跨流域水库群为对象进行研究,计算结果表明:① 减少了水量损失,提高了水资源的利用率;② 提高了供水区唐山、天津的供水保证率,降低了缺水破坏深度。     

地下水中砷元素的形成及其控制因素

研究了长江中下游地区和吉林省地区地下水中砷元素形成和主要控制因素及其分布规律。结果表明,地下水中砷主要以H_3ASO_3、H_2AsO_4~-、HA_3O_4~(2-)等形式存在。它的形成和分布与含水介质及其上覆土层的砷含量、地下水的酸碱度、地下水的迳流条件、氧化还原环境、有机物质及铁锰等有密切的关系。     

长江口理化因子影响初级生产力的探索Ⅰ.营养盐限制的判断方法和法则在长江口水域应用

营养盐限制浮游植物的生长是近年来国际研究的热点。探讨了目前营养盐限制的判断方法，认为仅靠氮和磷比值来得到磷限制或氮限制的结论是不完善的。根据营养盐限制的判断方法和法则，对长江口水域进行综合分析，认为在长江口及其附近海域，磷不是浮游植物生长的限制因子，而且氮、磷的浓度值都高于限制浮游植物生长的阈值，满足浮游植物的生长。通过1985年8月至1986年8月的长江口调查数据分析，发现从长江河口到远海水域的有些断面上，磷酸盐浓度并不一定离岸越远越低，且也没有周期性的季节变化。因此，尚须对河口区磷酸盐来源作进一步研究。