Predicting the capability-polar-plots for dynamic positioning systems for offshore platforms using artificial neural networks

As the capability of polar plots becomes better understood, improved dynamic positioning (DP) systems are possible as the control algorithms greatly depend on the accuracy of the aerodynamic and hydrodynamic models. The measurements and estimation of the environmental disturbances have an important role in the optimal design and selection of a DP system for offshore platforms. The main objective of this work is to present a new method of predicting the Capability-Polar-Plots for offshore platforms using the combination of the artificial neural networks (NNs) and the capability polar plots program (CPPP). The estimated results from a case study for a scientific drilling vessel are presented. A trained artificial NN is designed in this work and is able to predict the maximum wind speed at which the DP thrusters are able to maintain the offshore platform in a station-keeping mode in the field site. This prediction for the maximum wind speed will be a helpful tool for DP operators in managing station-keeping for offshore platforms in an emergency situation where the automation of the DP systems is disabled. It is obvious from the obtained results that the developed technique has potential for the estimation of the capability-polar-plots for offshore platforms. This tool would be suitable for DP operators to predict the maximum wind speed and direction in a very short period of time.     

基于互逆强化模型和数理统计方法分析专家评分偏差问题与建议

"十二五"期间，高技术研究发展计划（863计划）作为引领科技发展的主要抓手之一，为提升中国整体科技实力和创新能力发挥了重要作用.验收评审专家有着评估课题完成水平、衡量科研成果产出价值的关键作用，其评分可靠性直接关系着计划实施成效评价的合理性.鉴于此，本文结合互逆强化模型和数理统计方法，以"十二五"863计划某领域课题验收为例，系统分析了专家评分的偏差问题并按表现将专家划分为8种偏差类型并分别给出应对建议.结果表明：该领域技术验收专家评分整体合理，多数专家均能给出可靠评分；宽严尺度虽然略有差异，但处于可接受范围.本文研究将为国家科技计划相关评审工作乃至其他科研管理活动中合理开展专家评价、精细化规范评审行为以及完善领域专家库、遴选专家评委人选提供参考.     

Endemic avifaunal biodiversity and tropical forest loss in Makira, a mountainous Pacific island

Anthropogenic habitat changes and the introduction of pigs, dogs, cats and rats have caused a catastrophic decline in the terrestrial biodiversity of Pacific archipelagos. At present, economic globalization and an increased demand for timber are promoting industrial logging and plantation expansion. Commercial logging can be sustainable but in practice it more often leads to land degradation, especially on small flat islands. On large and mountainous islands, however, more modest impacts can be expected as the narrowly endemic species tend to inhabit montane forests where logging is difficult. In this study we use ornithological data collected at different elevations to assess the extent to which the avifauna of Makira, a large mountainous island in Melanesia, will be affected by deforestation of the lowlands, most of which are under timber concessions. Our data suggest that a majority of the endemic bird species use lowland forest to some extent and that this may even apply to species hitherto associated with montane forest. If current commercial forestry programmes are continued, the forest habitat may be disturbed or lost over large parts of Makira, potentially undermining the natural resource base for the local subsistence economy, exacerbating climate change and threatening the integrity of one of the most important areas for biodiversity conservation on earth. Our study highlights the importance of understanding the habitat requirements of endemic species and the urgency of establishing and effectively managing community-based protected areas in suitable lowland forests of the Pacific.     

内蒙古准格尔旗丘陵沟壑区退耕还林(草)模式

根据准格尔旗的自然环境特点,社会经济状况,以及水土流失及沙漠化灾害的特点,总结出适用上述条件下的退耕还林(草)的几种模式,恢复生态,发展经济。     

高分一号遥感卫星数据林地信息快速提取方法的研究

不同类型的林地具有不同的反射率特征,由此计算获得林地识别与分类的归一化植被指数(NDVI)。NDVI可参与对高分一号遥感图像的监督分类:首先根据图像光谱特征及NDVI参数,在ENVI专业图像处理平台上,选择各类林地的典型样本区,进行计算机自动信息提取,获得每个像素点属于某类林地的相似度信息,然后结合纹理、形状、空间关系等特征,利用聚类分析和迭代运算等综合处理方法,快速得到具有实用性的专题分类矢量结果。该方法光照度相对较弱的阴坡和薄云覆盖下的林地分类识别效果也比较好。通过对光谱角填图法、马氏最小距离法、最大似然法等监督分类的结果进行比较,认为采用光谱角填图法提取高分一号卫星原始数据的林地矢量信息精度最高。     

地层剖面测量的数据处理及绘图程序

简要介绍了以野外地层剖面测量的原始数据为基础的数据处理及绘图程序。     

基于生态系统服务价值核算的土地利用规划战略环境评价

以生态系统服务价值为评价指标,对河北省易县的土地利用总体规划进行了战略环境评价。结果表明,从1997年到2010年期间,易县的土地利用的生态系统服务价值呈增加趋势,从生态环境保护和自然资源利用角度,表明此规划基本合理。但生态价值的增长速率小于其GDP的增长速率,显示该土地利用规划还存在一些问题,需对该规划做一些修改与补充。     

特深岩心钻孔套管程序和钻具级配等问题的探讨

讨论了特深岩心钻孔钻探施工的套管程序、钻具及其级配和固井等问题,深入分析了这些技术问题对特深孔钻探施工的风险性和经济性的影响作用。在分析研究的基础上,提出了对我国施工特深岩心钻孔时的套管程序、钻具级配、特深孔钻杆柱、套管柱以及固井等技术方案的建议。     

一种基于空间网格的地物要素点云提取方法

LiDAR点云的分类提取是点云数据处理中的首要步骤。为了提高复杂场景中点云数据分类提取方法的适用性,文中根据三维数学形态学思想,提出一种基于地物空间形状特征的点云提取方法。方法首先建立网格索引,划分网格空间,进行点云数据组织,然后根据地物在网格空间中的形状特征设计出四种参数可控的空间网格算子,最后结合点云反射强度信息自动提取特定地物点云。通过对复杂场景中的铁路地物要素LiDAR点云中建筑、电力杆线、铁路轨道的提取和郊区机载LiDAR点云中的地面与建筑屋顶的提取,验证提取算法的适用性,为点云分类提取功能模块的程序设计提供便捷方法。     

基于AutoCAD的无属性的高程图形数据的处理

在传统的测绘方式中,由于受成图方式和制图软件的限制,一些数字化成果的高程数据没有属性,给数据处理和利用造成了一定的麻烦。介绍了通过利用计算机程序解决这一问题,在实际应用中效果较好。