基于智能对象的决策支持系统体系结构研究

分析了决策问题及其求解过程,揭示了传统IDSS体系结构的不足,阐述了应用面向对象的结构化知识表达构造智能对象,提供了智能决策过程支持的方法和新的IDSS体系结构,并在农业空间决策信息系统的实践中进行了验证。     

视频对象分割及跟踪方法研究

讨论和分析了视频对象全自动提取及后续帧中的跟踪过程及采用的方法,对其算法、分割性能和结果进行了比较和评述。并结合Hausdorff和Snake跟踪器,对初始对象轮廓进行跟踪。结果证明,这种跟踪方法能有效地解决对象被遮挡和形变以及背景移动的问题。     

集成高度和彩色纹理特征的影像目标模糊聚类识别方法

提出一种基于高度和彩色纹理信息的目标识别方法 ,其目的是提取具有相对高度的地物。由于传统二维纹理分析的方法往往不能有效地提取这类目标 ,本文把高度、色彩和纹理信息有机地结合起来 ,提高了识别率。依据影像提取结果 ,探讨了树林对森林覆盖地区自动空中三角测量选点的负面影响 ,同时建议采用数据分组的方案来改善森林覆盖地区自动空中三角测量的精度 ,并用对比实验证明了其有效性。     

空间目标的聚合模型

本文定义了集合元素的聚合算子，简述其特性，以此聚合算子为基础，提出了空间目标的聚合模型。根据ＧＩＳ空间目标的属性，分析了聚合算子的表现形式。由此模型的特点可以得出：聚合模型适合于ＧＩＳ层次数据的组织，它能减少数据的冗余和维护数据的一致性。经概念及含义的比较，指出了面向对象的模型方法很适合此聚合模型的实施。     

地理信息系统基础软件吉奥之星NT版的总体设计思想与关键技术

介绍了新一代面向对象的GIS基础软件系统吉奥之星NT版的总体设计思想、系统结构、功能特点和有关关键技术。     

基于面向对象的空间目标3维交互式建模的设计

3维数据模型的建立是实现真3维GIS的一个核心问题。在充分分析现有3维数据模型的基础上，比较了传统模型的优缺点。针对空间目标建模的特点，设计了一种面向对象的3维数据模型。考虑到软件的实用性和可扩展性，着重论述了3维交互式设计及数据管理。     

Numerical prediction on the scour burial of cylinder object freely resting on the sandy seabed in the East China Sea using the DRAMBUIE model

After experiencing 8-day combined tidal current, circulation and wave actions, scour depth surrounding cylinder object freely resting on sandy seabed in the East China Sea （ECS） in January is numerically predicted using the DRAMBUIE model designed for scour burial, which has been widely used and verified by in-situ experiments. During the period of numerical integration, the value of time t is generally variable at every time step via the special time-stepped approach developed by this paper to eliminate the time error. The tidal current velocity, wave orbital velocity and the depth-averaged circulation in the ECS have been obtained by numerical simulations with Estuarine Coastal and Ocean Model （ECOM）, Simulating Waves Nearshore （SWAN） model and Regional Ocean Modeling System （ROMS） model respectively. The control experiment and several idealized test cases on influential factors in scour depth reveal that the dominant hydrodynamic factor is tidal current in the ECS under normal weather conditions, and the impacts of shelf circulation and wave motion on local scour almost can be ignored with an exception of the Kuroshio area where the high-speed mainstream of Kuroshio flows. It is also indicated that in sandy sediments, the distribution of scour depth nearly follows the pattern of tidal currents, while the secondary influencing factor on scour depth appears to be grain size of sandy sediment in the ECS. Numerical tests on sediment grain size further testify that much finer sand is more easily scoured, and an increasing trend for scour depth with reduction of grain size is displayed due to imposed resistance of larger sized particles. Three aspects explored by this paper, including the empirical equations in the Defense Research Agency Mine Burial Environment （DRAMBUIE） model, the accuracy of inputs and infill process can severely affect the prediction of scour depth surrounding cylinder objects freely resting on sandy seabed in the ECS.     

Uncertainty assessment of ephemeral gully identification,characteristics and topographic threshold when using aerial photographs in agricultural settings

Manual digitizing on aerial photographs is still commonly used for characterizing gully erosion over large areas. Even when automated detection procedures are implemented, manual digitizing is frequently being resorted to in order to constitute reference datasets used for training and validation. In both cases, manual digitizing entails some subjective decisions on behalf of the operator, which introduces uncertainty into the resulting datasets. To assess the magnitude of this uncertainty, 11 experienced operators were asked to digitize and classify ephemeral gullies (EGs) on cropland following a standardized methodology. The resulting 11 datasets were compared in terms of number, type and location of EGs. Furthermore, for EGs located on a well‐defined runoff flow concentration axis, the slope versus contributing area topographic thresholds required for initiating gully channels were assessed using four thresholding methods, and compared across the 11 datasets. The operators identified 259 different EGs. However, the number (52–139) and sum total length (8.9–23.7 km) of EGs varied widely across operators. Only 34% of the EGs were digitized by more than half of the operators, and 7% were identified by all. Identification of EGs located on a well‐defined flow concentration axis proved least subjective. The longer the EG and the more fields the EG crossed, the larger the number of operators that were able to identify it. EGs were also most easily identified when located in sugar beet fields as compared to other crops. EG classification and topographic threshold lines were also found to be strongly operator‐dependent. Quantile regression appeared to be one of the most robust thresholding methods. Operator subjectivity when digitizing EGs on orthophotographs introduces uncertainty that should be taken into account in future remote sensing‐based studies of EG erosion whenever they rely, in part or in full, on manual photograph interpretation. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of river channel morphology and bank characteristics on water surface boundary delineation using high‐resolution passive remote sensing and template matching

Accurate mapping of water surface boundaries in rivers is an important step for monitoring water stages, estimating discharge, flood extent, and geomorphic response to changing hydrologic conditions, and assessing riverine habitat. Nonetheless, it is a challenging task in spatially and spectrally heterogeneous river environments, commonly characterized by high spatiotemporal variations in morphology, bed material, and bank cover. In this study, we investigate the influence of channel morphology and bank characteristics on the delineation of water surface boundaries in rivers using high spatial resolution passive remote sensing and a template‐matching (object‐based) algorithm, and compare its efficacy with that of Support Vector Machine (SVM) (pixel‐based) algorithm. We perform a detailed quantitative evaluation of boundary‐delineation accuracy using spatially explicit error maps in tandem with the spatial maps of geomorphic and bank classes. Results show that template matching is more successful than SVM in delineating water surface boundaries in river sections with spatially challenging geomorphic landforms (e.g. sediment bar structures, partially submerged sediment deposits) and shallow water conditions. However, overall delineation accuracy by SVM is higher than that of template matching (without iterative hierarchical learning). Vegetation and water indices, especially when combined with texture information, improve the accuracy of template matching, for example, in river sections with overhanging trees and shadows – the two most problematic conditions in water surface boundary delineation. By identifying the influence of channel morphology and bank characteristics on water surface boundary mapping, this study helps determine river sections with higher uncertainty in delineation. In turn, the most suitable methods and data sets can be selectively utilized to improve geomorphic/hydraulic characterization. The methodology developed here can also be applied to similar studies on other geomorphic landforms including floodplains, wetlands, lakes, and coastlines. Copyright © 2014 John Wiley & Sons, Ltd.     

孟连至包头地震期间地震的天体位置分析

本文分析了孟连地震至包头地震间中国发生的五次地震的天体位置。该五次震例都处于朔望日发震,且交替呈现,为中国地震史上最集中出现的群发朔望震。对此本文作了一些朔望对地震发机制的初步探讨,此外,也对引潮加速度对地震触发作用进行了计算和分析。