视觉显著性与知觉组织相结合的高分影像居民地提取方法

受人类视觉认知机制的启发,提出了一种利用视觉显著性与知觉组织相结合的高分辨率遥感影像居民地提取方法。首先利用认知物理学中的数据场构建居民地的视觉显著性模型,并通过自适应阈值法实现候选居民地的自动提取,然后利用多尺度小波变换的高频特征实现居民地的知觉组织,最后通过集合交运算提取同时满足这两种视觉机制的居民地。通过ZY-3和Quickbird两种高分传感器的影像数据集进行居民地提取试验,验证了该方法的有效性。     

专题地图图面要素自动配置方法的研究

实现地图图面要素配置的自动化是地图制图自动化中的一个重要部分,能够帮助制图人员提高制图效率。文中在分析国内外有关研究成果的基础上,利用地图图面配置规律和视觉平衡理论,提出一种自动搜寻地图图面要素合适位置的方法。该方法从专题地图生产的实际需要出发,考虑了纸张大小和地图比例尺等因素,用矩形框表示图面要素的大小和位置,简化设计过程。最后,在CorelDRAW环境下,利用VBA技术实现文中所提出的方法。该软件提供了多种地图图面要素配置模板供地图设计人员选择,能进行地图图面要素位置的自动冲突探测,可以为地图设计人员提供一个标准化地图图面配置模板。     

GeoSOT-3D椭球体剖分真三维数据表达

随着地球观测技术和信息技术的进步,以全球为背景的科学探索不断增多,不仅是地球表面信息,地下、水下、空中等地球上各个层次的空间信息都受到极大的关注。地球球体剖分网格可以构建真三维的数据模型,进而实现空天地、地下水下一体化的空间数据组织、管理、表达与应用。本文详细论述了GeoSOT-3D椭球体剖分网格的剖分空间框架、剖分编码与剖分尺度特性等理论体系。建立基于GeoSOT-3D的空间对象的真三维表达模型。利用该真三维模型实现了地球椭球体的地上地下可视化,点线面体等空间实体的可视化。研究表明,GeoSOT-3D椭球体剖分具有椭球剖分框架简单、体系完整、二三维一致等特点,因而在该框架下的真三维数据模型可用于下一代地理信息系统中的空间大数据的组织管理与表达。     

面向自然连续面群边线的协同化简方法

自然连续面群边线化简是地形图中自然面状要素和地理国情普查数据中自然图斑自动制图综合的重要实施步骤。现有面要素边线化简算法大多以线化简算法为基础,未有效化简弯曲特征、保持面积平衡和满足图面视觉清晰性要求,且化简结果存在共享边界不一致、边线自相交和边线之间相交的拓扑问题。为此,结合自然连续面群表达特点和化简要求,本文提出一种面向自然连续面群边线的协同化简方法。首先将自然连续面群转换为拓扑数据结构组织,以待化简弧段及其相邻弧段为基础构建约束Delaunay三角网,标识化简区域;其次利用弧段双侧层次多叉树模型渐进式退化条带状弯曲、化简细小弯曲;最后自适应夸大狭窄“瓶颈”,实现边线的协同化简。以河南省某区域1:5万地形图中的植被与土质面要素进行化简实验,相较于对比方法,该方法能够有效保持自然连续面群边线化简前后的拓扑一致性、要素之间的面积平衡,充分化简目标尺度下的局部不清晰细节,化简结果精度高。     

从中国目视资料分析1998年狮子座流星雨

本文分析了１９９８ 年狮子座流星雨的一部分中国目视资料。资料启示：１９９８ 年狮子座流星雨来自两股不同组成的流星体颗粒的不均匀混合流。按照这种观点进行了以这些目视资料为基础的计算,从而解释了目视观测与雷达观测所得结果之间的矛盾。     

地理信息系统集成平台框架结构研究

提出了基于客户／服务器结构的地理信息系统集成平台总体结构,探讨了基于元数据的地理信息系统数据集成平台以建立物理上分布而逻辑上集中的分布式地理信息系统数据库,提出了应用符合３ＮＦ范式的关系数据库进行模型管理的模式,在此基础上探讨了地理信息系统可视化建模工具。     

An Analysis of the Coastal Fish Assemblage of the Ustica Island Marine Reserve (Mediterranean Sea)

A study of the coastal fish assemblages in the marine park of Ustica Island (Southern Tyrrhenian Sea, Mediterranean) was conducted from June 1994 to September 1995 and from June 1996 to September 1997. The principal aims of the research were to: (1) define the faunistic features of local fish communities; (2) assess the effectiveness of the protection regime of the marine park on the fish assemblages ('reserve effect'); (3) provide information on the distribution of some Epinephelus and Diplodus species in the shallowest depth zone of the island. During seasonal surveys, underwater visual censuses were carried out at several sites located in three zones of the island, each with a different level of protection. Observations were made along 250 m² transects at 3–5, 10–15 and 25–30 m depth ranges. Additional surveys were made by SCUBA diving and snorkelling. A statistically significant effect of depth on the fish community parameters was observed, whereas differences linked to protection level, zones, sites and seasons were not significant. The abundance and frequency of occurrence of some species, particularly dusky grouper Epinephelus marginatus , were positively correlated with the degree of protection of the different zones of the marine park. Certain sites of the island are important as nursery areas for three species of the genus Diplodus ( i.e., D. puntazzo, D. sargus and D. vulgaris ).     

双壳贝类CK1基因家族的鉴定及表达分析

酪蛋白激酶1 (CK1)是一种重要的蛋白激酶家族,其在DNA损伤应答和修复、细胞增殖和凋亡、胚胎发育和稳态等重要的生物学过程中都具有复杂多样的调控作用。为了理解CK1基因家族在双壳贝类中的特征、进化及生物学功能,实验采用比较基因组学及生物信息学的方法对双壳贝类CK1基因家族进行了鉴定分析,通过虾夷扇贝高温应激实验,研究了CK1基因家族在高温应激时的表达规律。结果显示,在虾夷扇贝、栉孔扇贝、长牡蛎与侏儒蛤中均存在CK1α,CK1αlike,CK1δ,CK1γ3,并发现CK1ε,CK1γ1,CK1γ2在双壳贝类中发生了丢失。时空表达分析发现,双壳贝类CK1基因均在胚胎发育早期集中表达,并以多细胞/囊胚期为界呈现出母源/合子特异性表达模式。CK1为关键基因的基因共表达模块显著富集在错配修复、核苷酸剪切修复等相关通路上,暗示了CK1基因在双壳贝类胚胎发育过程中参与调控DNA损伤修复过程,从而维持早期胚胎发育时的基因组稳定性。双壳贝类CK1基因在成体中呈现组织特异的表达模式,主要在鳃和雄性性腺中具有相对较高的表达量。虾夷扇贝受到高温应激后,其鳃中PyCK1α, PyCK1αlike和PyCK1δ...     

Visual characterization technique for gravel‐cobble river bed surface sediments; validation and environmental applications Contribution to the programme of CIRSA (Centre Interuniversitaire de Recherche sur le Saumon Atlantique)

This paper presents an evaluation of the feasibility and the reliability of a visual characterization technique for gravel–cobble river bed surface substrate. Based on principal axis regressions, using phi scale (ϕ), comparisons of visual estimation and grid sampling techniques show that useful predictive relations (R² = 0·78–0·88) exist between visual estimates of the surface d₁₆, d₅₀ and d₈₄ and estimates obtained for the same percentiles with the grid sampling technique. Comparisons of visual estimation and the surface‐bulk sampling technique also indicate a predictive relation (R² = 0·70) between the d₅₀ of the two methods. Trained operators can visually estimate gravel–cobble bed surface d₁₆ to uncertainties of 41 per cent, d₅₀ to 15 per cent and d₈₄ to 11 per cent (for example, there is a 5·5 mm error on a d₈₄ size of 50 mm). Furthermore, evidence shows that if operators are properly trained, a calibration relation for each percentile can be applied independently of operators. This visual characterization allows effective detailed mapping of spatial patterns in substrate size distribution along extensive reaches of gravel‐bed rivers. The technique can be very useful in creating terrain models for various geomorphological, hydrological and biological applications such as the determination of entrainment thresholds, hydraulic roughness and substrate suitability for benthic insects or salmonid habitat. Copyright © 2001 John Wiley & Sons, Ltd.     

DATABASE OF LANDSLIDES TRIGGERED BY 2015 GORKHA(NEPAL) MW7.8 EARTHQUAKE

In this study, a detailed database of landslides triggered by the 25 April 2015 Gorkha (Nepal)M_W7.8 earthquake is constructed based on visual interpretation of pre- and post-earthquake high-resolution satellite images and field reconnaissance. Results show the earthquake triggered at least 47 200 landslides, which have a NWW direction spatial distribution, similar with the location and strike of the seismogenic fault. The landslides are of a total area about 110km² and an oval distribution area about 35 700km². On the basis of a scale relationship between landslide area (A)and volume (V), V=1.314 7×A^{1.208 5}, the total volume of the coseismic landslides is estimated to be about 9.64×10⁸m³. In the oval landslide distribution area, the landslide number density, area density, and volume density were calculated and the results are 1.32km^-2, 0.31%, and 0.027m, respectively. This study provides a detailed and objective inventory of landslides triggered by the Gorkha earthquake, which provides very important and essential basic data for study of mechanics of coseismic landslides, spatial pattern, distribution law, and hazard assessment. In addition, the landslide database related to an individual earthquake also provides an important earthquake case in a subduction zone for studying landslides related to multiple earthquakes from a global perspective.