基于决策树的洪泽湖湿地信息提取

湿地是地球的重要组成部分,快速而准确地提取湿地信息,是湿地动态监测和可持续发展的一项基础而重要的工作.以洪泽湖淡水湿地为研究对象,采用2006年8月19日的Landsat5 TM遥感影像为数据源,采用经K-T变换光谱增强后的数据及利用灰度共生矩阵分析影像第一主成分的纹理统计量作辅助分类变量,基于地物光谱特征、纹理特征和形状特征,运用决策树分类法提取洪泽湖湿地植被信息,将其分类结果与最大似然法的分类结果进行比较.结果表明:1)洪泽湖地区的湿地植被比较丰富,面积约占全湖的10.74％,其中以浮水植物为主.2)基于决策树的分类结果的精度有了明显的提高,总精度由77.33％提高到86.33％,Kappa系数由0.7292提高到0.8354,证明基于决策树分类方法是提取淡水湿地植被信息的有效手段.     

基于改进的Bursa模型坐标转换的探讨

针对目前空间坐标转换方法,提出一种改进的Bursa模型,利用模拟数据的计算与分析,对该方法进行坐标转换的收敛与迭代情况,以及参数估计准确性做了相关探讨,表明该方法可以求解任意欧拉角的坐标系转换。     

历史文化名城改造中城市更新概念的衍生、想象和认知局限性——以佛山岭南天地“三旧”改造为案例

以佛山市“岭南天地”(祖庙-东华里历史文化街区)的“三旧”改造为案例,讨论历史文化名城核心区改造中城市更新概念的衍生、想象及认知局限性.尤其侧重于概念运用在历史文化名城老城核心区更新中的作用、价值及其在更新实践中的推动或限制因素.研究显示,“三旧”改造概念作为城市更新理念与佛山城市旧区改造的现实问题相互结合而衍生的“应景”产物,在运用中凝练了更新主体(地方政府)对旧区改造发展的愿望、想象和认知倾向.这使得“三旧”改造概念在历史文化名城城市更新中的应用存在部分的局限性.另一方面,“三旧”改造发展模式及其想象展望也可能只是地方政府及开发商谋求城市、产业发展和城市综合竞争力提升的一种手段.此外,研究显示,“三旧”改造概念只被地方政府和投资人用作组织与寻求他们各自关注点的一种达到目的的手段或技术,从本质上来说,这个概念对他们的吸引力在于与之相关联的资源,以及一种供使用、阐释、替换的语言.至于这个概念对历史文化名城城市更新的实用性,则似乎关注不够.     

基于SLM模型的中国碳排放格网化空间分布模拟

以美国橡树岭国家实验室二氧化碳信息分析中心的中国碳排放数据、统计年鉴中的分省化石能源消费与水泥产量数据为基础,选取NDVI植被指数、DMSP/OLS夜间灯光数据、GDP、工业总产值、人口5个指标,对中国2000年及2010年的分省碳排放结果采用5km×5km格网,运用空间滞后回归模型(SLM)进行空间分布模拟,并对空间模拟结果进行误差分析及纠正,获得2000年及2010年地均碳排放强度空间分布图。结果表明,中国地均碳排放强度存在以下特征:区域差异分布特征明显,主要表现为从东部地区向中西部地区逐渐变小;存在几个明显高值热点及低值冷点区域;随着时间的推移,地域差异特征越发明显,冷点和热点区域分布特征更加显著;2010年各地区地均碳排放强度明显大于2000年。     

WATER RESOURCES TRANSFORMATION AND WATER QUALITY VARIATION IN THE URUMQI RIVER BASIN

ＷＡＴＥＲＲＥＳＯＵＲＣＥＳＴＲＡＮＳＦＯＲＭＡＴＩＯＮＡＮＤＷＡＴＥＲＱＵＡＬＩＴＹＶＡＲＩＡＴＩＯＮＩＮＴＨＥＵＲＵＭＱＩＲＩＶＥＲＢＡＳＩＮＱｕＹａｏｇｕａｎｇ（曲耀光）；ＬｕｏＨｏｎｇｚｈｅｎ（骆鸿珍）（ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＧ...     

WGS-84与北京54坐标的转换问题

GPS测量得到的是WGS-84中的地心空间直角坐标，而工程施工中通常使用地方独立坐标系，要求得到地方平面坐标。如何实现两者的转换，一直是工程施工中关心的热点问题。介绍了从GPS定位结果至平面坐标的两种转换模型。平面转换模型原理简单，数值稳定可靠，但只适用于小范围的GPS测量；空间转换模型可用于大范围GPS测量，按实际情况又分为7参数转换和3参数转换两种。鉴于54坐标点的大地高通常不能精确得知，对这两种转换方法得到的平面坐标的精度进行了比较，得出大地高精度主要表现为对高程的影响，对平面坐标影响较小的结论。此外，还讨论了7参数与3参数模型对转换结果的影响。     

潮汐形变资料中地震前兆信息的识别与提取

将小波变换的多分辨率分析引入潮汐形变资料处理中，对近年来云南地区的3次强震前的潮汐形变观测资料进行了处理与分析，发现在地震前2～5个月，震中附近的形变台站都接收到一个频段相同的异常信号，且它们之间是相关的，相关系数达80％以上，由此可以确定信号是由同一个源发出来的。出现在多个台站的相同频段的异常信号很可能就是我们想要得到的地震前兆信息。     

Partial Reduction in the N-Body Planetary Problem using the Angular Momentum Integral

We present a new set of variables for the reduction of the planetary n-body problem, associated to the angular momentum integral, which can be of any use for perturbation theory. The construction of these variables is performed in two steps. A first reduction, called partial is based only on the fixed direction of the angular momentum. The reduction can then be completed using the norm of the angular momentum. In fact, the partial reduction presents many advantages. In particular, we keep some symmetries in the equations of motion (d'Alembert relations). Moreover, in the reduced secular system, we can construct a Birkhoff normal form at any order. Finally, the topology of this problem remains the same as for the non-reduced system, contrarily to Jacobi's reduction where a singularity is present for zero inclinations. For three bodies, these reductions can be done in a very simple way in Poincaré's rectangular variables. In the general n-body case, the reduction can be performed up to a fixed degree in eccentricities and inclinations, using computer algebra expansions. As an example, we provide the truncated expressions for the change of variable in the 4-body case, obtained using the computer algebra system TRIP.     

An alternative deduction of the hill-type surfaces of the spatial 3-body problem

In the present paper, inequalities stronger than Sundman's and the best possible zero velocity surfaces of the spatial 3-body problem first obtained by Saari (1987) are deduced using a modified version of the transformation developed by Zare (1976). The notion of inertia ellipsoid is used to show the equivalence of the present authors' result to that of Saari's.     

Metagabbro and associated eclogites in the Lubrin area, Nevado-Filabride Complex, Spain

Abstract Several small bodies of metabasite (maximum dimensions of 1000 m x 500 m) are included in the metamorphic rocks of the Nevado-Filabride Complex in the Betic Cordilleras (Almeria Region). The body of 400 m x 100 m, located 200 m due west of the Lubrin village, contains troctolitic gabbro with well-preserved igneous textures and mineral compositions, wholly amphibolitized gabbro, garnet-bearing metagabbro eclogite. Along with the textural and mineral changes, sensible and regular geochemical variations can be observed, where the content of MgO decreases from 24% to 11%, while that of CaO and Na₂O increases from 7% to 11% and from 2% to 3%, respectively. In addition, the content of some minor elements such as Sr, Y, Nb, Zr and Sc increases while that of Ni and Cr decreases from troctolitic gabbro to the eclogite. The amphibolitized gabbro shows values scattered around those of the troctolitic gabbro. These geochemical variations are ascribed to inherited differences in the pre-metamorphic protolith, i.e. a fractionated gabbro which varies from olivine-rich to clinopyroxene-rich gabbro. Nevertheless, some metasomatism affected the Lubrin body without changing the main chemical trends, as documented by the significantly different ⁸⁷Sr/⁸⁶Sr ratios of each rock-type. This points to a metasomatism which involved the introduction of crustal radiogenic strontium. The petrographical and mineral chemical features are interpreted to be the result of syn-metamorphic fluid circulation possibly combined with deformation by shearing. The igneous texture and mineral chemistry have been retained wherever both fluid circulation and shearing were ineffective. On the contrary, where both events were effective, the formation of eclogite occurred. Later, the entire body underwent a retrogressive amphi-bolitic stage under greenschist facies conditions, which was probably responsible for the formation of the amphibolitized gabbro portion and for the retrogression of the eclogite.