济南市建成区扩展的时空特征及驱动力分析

以山东省济南市为例,以1979—2005年5个不同时相的遥感图像为数据源,利用遥感信息提取技术,获取了城市扩展的空间信息。结合济南市社会经济统计数据,从扩展方向、重心转移等方面综合分析了济南市建成区扩展的时空特征,并从人口、经济、地理区位、政策导向等4个方面探讨了城市扩展的驱动力。结果表明,济南市城区扩展的整体趋势是东西向的带状扩张,向东扩张明显,城市重心向东北方向转移;1979年济南市城区面积是52．7km^2,2005年达到311．6km^2,是1979年的5．9倍。     

Systematic marine conservation planning in data-poor regions: Socioeconomic data is essential

Systematic planning for conservation is highly regarded but relies on spatially explicit data that are lacking in many areas of conservation concern. The decision support tool Marxan is applied to a reef system in the central Philippines where 30 marine protected areas (MPAs) have been established in communities without much use of biophysical data. The intent was to explore how Marxan might assist with the legally required expansion to protect 15% of marine waters, and how existing MPAs might affect that process. Results show that biophysical information alone did not provide much guidance in identifying patterns of conservation importance in areas where the data are poor. Socioeconomic data were needed to distinguish among possible areas for protection; but here, as elsewhere in marine environments, the availability of such data was very limited. In the final analysis, local knowledge and integrated understanding of socioeconomic realities may offer the best spatially explicit information. The 30 existing MPAs, which encompassed a small proportion of the reef system, did not limit future options in developing a suite of MPAs on a broader scale. Rather, they appeared to generate the support for MPAs that is obligatory for any larger zoning effort. In summary, establishing MPAs based on community-driven criteria has biological and social value, but efforts should be made to collect ecological and socioeconomic data to guide the continued creation of MPAs.     

The new wave overtopping database for coastal structures

Significant effort has been made to generate a homogeneous database on wave overtopping consisting of more than 10,000 irregular wave overtopping tests from more than 160 independent projects or test series, each described by means of 31 parameters. Many coastal structures, including dikes, rubble mound breakwaters, berm breakwaters, caisson structures and combinations have been considered and have been schematised for inclusion in the database. All these overtopping tests are represented by over 300,000 numbers in the database.     

Mixed layer depth climatology of the North Pacific based on Argo observations

A monthly mean climatology of the mixed layer depth (MLD) in the North Pacific has been produced by using Argo observations. The optimum method and parameter for evaluating the MLD from the Argo data are statistically determined. The MLD and its properties from each density profile were calculated with the method and parameter. The monthly mean climatology of the MLD is computed on a 2° × 2° grid with more than 30 profiles for each grid. Two bands of deep mixed layer with more than 200 m depth are found to the north and south of the Kuroshio Extension in the winter climatology, which cannot be reproduced in some previous climatologies. Early shoaling of the winter mixed layer between 20–30°N, which has been pointed out by previous studies, is also well recognized. A notable feature suggested by our climatology is that the deepest mixed layer tends to occur about one month before the mixed layer density peaks in the middle latitudes, especially in the western region, while they tend to coincide with each other in higher latitudes.     

船体可靠性评估

为了研究不同结构船体的寿命和使用时可靠度的关系,提出了一种基于试验的可靠度估计方法.针对不同结构船体寿命服从Weibull分布,在无失效数据情形下、置信度至少为γ和寿命为t时,根据船体寿命试验数据,给出了可靠度的单侧置信下限.该方法是在Weibull分布形状参数下限已知的情况下,能将所有的无失效寿命数据进行累加,大大提高了可靠性分析的精度.最后,对钢结构、钛合金结构、铝合金结构的船体,在寿命为t月、置信度至少为γ时,计算了3种结构船体的可靠度单侧置信下限.结果表明该方法易于计算,便于工程应用.     

地理信息公共服务平台地理实体数据建模研究

围绕国家地理信息公共服务平台在线地理信息服务的需求,在分析国内外相关成果的基础上,提出了面向实体的数据建模思路,设计了地理实体数据模型,能够方便地实现地理信息与社会、经济、自然资源等专题信息的挂接,并有效解决多比例尺实体目标的一致性维护问题.     

集合卡尔曼滤波在流域水文模型流量预报中的应用

针对流域降雨入渗过程,引入集合卡尔曼滤波(EnKF)理论,视整个边坡流域为一个随机动态系统,将边坡流域流量观测值作为系统的输出,用集合卡尔曼滤波模型来描述系统的状态;结合流域流量计算方法,实现水文模型参数的随机动态估计,在有效获得待估参数的同时还给出估计值的不确定性.通过数值算例表明,集合卡尔曼滤波可以有效地对含噪声的量测数据进行处理,能够跟踪水文模型的动态变化.相对于常用最优化算法,集合卡尔曼滤波同时给出反演结果和先验知识的后验分布,显示出更好的实时性和可靠性.     

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地理信息公共服务平台的总体技术设计研究

国家地理信息公共服务平台建设与运行维护是一项超大型地理信息工程。为了切实做好统筹规划、统一设计、规范建设、分步实施,国家测绘局组织开展了总体技术设计研究,制订了技术设计指南。本文介绍了国家地理信息公共服务平台总体设计的基本思路和总体架构。     

Extending self-organizing maps for supervised classification of remotely sensed data

An extended self-organizing map for supervised classification is proposed in this paper. Unlike other traditional SOMs, the model has an input layer, a Kohonen layer, and an output layer. The number of neurons in the input layer depends on the dimensionality of input patterns. The number of neurons in the output layer equals the number of the desired classes. The number of neurons in the Kohonen layer may be a few to several thousands, which depends on the complexity of classification problems and the classification precision. Each training sample is expressed by a pair of vectors ： an input vector and a class codebook vector. When a training sample is input into the model, Kohonen＇s competitive learning rule is applied to selecting the winning neuron from the Kohouen layer and the weight coefficients connecting all the neurons in the input layer with both the winning neuron and its neighbors in the Kohonen layer are modified to be closer to the input vector, and those connecting all the neurons around the winning neuron within a certain diameter in the Kohonen layer with all the neurons in the output layer are adjusted to be closer to the class codebook vector. If the number of training sam- ples is sufficiently large and the learning epochs iterate enough times, the model will be able to serve as a supervised classifier. The model has been tentatively applied to the supervised classification of multispectral remotely sensed data. The author compared the performances of the extended SOM and BPN in remotely sensed data classification. The investigation manifests that the extended SOM is feasible for supervised classification.