一种新颖的亚像素级SAR图像水陆分割方法

星载合成孔径雷达(Synthetic Aperture Radar,SAR)图像水陆分割对水域识别、洪水监测等领域研究具有重要意义。然而,星载SAR图像的空间分辨率通常在米至十米量级,水域边界上会存在大量既包含陆地又包含水域的混合象元。传统像素级水陆分割算法难以获取高精度的水陆分割结果。本文提出一种新颖的亚像素级SAR图像水陆分割方法,该方法采用一种改进的非局域滤波算法抑制相干斑噪声,再利用模糊C均值聚类算法进行像素级水陆分割,在此基础上应用基于双三次样条插值与几何主动轮廓模型的精分割方案,获取更高精度的亚像素级水域轮廓。本文以南水北调中线工程水源地——丹江口水库为实验区域,利用国产高分三号（GF-3）卫星的多模式SAR图像,开展水陆分割验证实验。实验结果表明,所提方法可实现亚像素级精度的水陆分割,与传统方法相比,平均像素偏移精度提升一个数量级。     

河南省水生态文明建设试点城市生态系统健康评价

在总结城市生态系统的属性并分析其健康内涵的基础上, 通过频度统计法, 建立评价指标体系。采用海明贴 近度, 建立模糊物元模型, 对河南省第一批水生态文明城市建设试点郑州、 洛阳、 许昌 2000 年- 2013 年间城市生态 系统的健康水平进行评价, 分析影响城市生态系统健康发展的各要素, 结果表明: 郑州、 洛阳和许昌整体的城市生态 系统健康水平呈上升趋势, 但健康改善程度并不显著, 且部分指标有恶化趋势; 相同时期内, 城市生态系统的健康水 平排序由高到低依次为郑州、 洛阳、 许昌, 但其增长速率则为许昌最快、 郑州最慢; 各城市不同要素之间的健康程度 差别较大, 且不同城市各要素之间的协调性较低。因此, 未来应针对健康程度较差的要素重点发展, 提高各要素之 间的协调性, 进一步提高城市生态系统整体的健康水平。     

‘Why Can’t the Future be More Like the Past?’ Planning History Track,Association of European Schools of Planning (AESOP), Annual Congress,Department of Civic Design,University of Liverpool, 15–18 July 2009

AESOP’s 2009 Congress was hosted by the University of Liverpool as part of the centenary celebration of its Department of Civic Design, the world’s oldest university planning school. ‘Why Can’t the Future be More Like the Past?’ was the conference title on all the banners and conference bags – an oddly querulous question, nevertheless it did the trick in getting participants to think historically throughout AESOP 2009. Michael Hebbert and Dirk Schubert ran a planning history track for six of the conference’s seven parallel session slots. Their call for papers elicited 30 abstracts which reduced to 17 papers, a comfortable quantity allowing good time for presentation and discussion. The track had the fortune to be allocated a wood‐panelled Architecture lecture theatre with superb projection facilities – more than one speaker gasped at the glory of their own PowerPoint images.     

The rational method in stormwater management modelling of peak flow flood control systems,II: Computer program application

The companion paper's development of the well-known Rational Method is used to prepare a computer program to estimate T-year return frequency peak flow rates for flood control and environmental planning purposes. When applied, the computer program results indicate the usufulness of the Rational Method for estimating peak flow rates, and perhaps explain why the method continues to be widely used in civil engineering. The computer program solves for peak flow rates by solution of the stochastic integral equation representation of the Rational Method procedure, as derived in the companion paper.     

An algorithm for exact evaluation of multivariate functions and their derivatives to any order

A method is presented for automatically computing the exact value of all the partial derivatives up to any order of functions of several variables. The method uses principals developed previously for calculating first order derivatives but extends them with the principal of recursion to enable the calculation of higher order derivatives.     

The AMVA priority approximation

Most computer systems contain one or more system resources whose usage is controlled on the basis of workload priorities. Unfortunately, the exact analysis of queueing network models incorporating priority scheduling disciplines is usually infeasible. The MVA Priority Approximation has been proposed as a comparatively inexpensive, and yet reasonably accurate, approximation technique for queueing networks with priority scheduled service centers. Even this algorithm, however, is too expensive to apply to large networks with many classes of customers.In this paper, we show how the MVA Priority Approximation can be modified so that it utilizes approximate rather than exact Mean Value Analysis (MVA), without significant loss of accuracy. Extensive numerical experiments are performed to further assess the accuracy of the modified algorithm, termed here the AMVA Priority Approximation. These experiments utilize the parameter space mapping technique for studying ‘local’ queueing network approximations.     

Nonlinear beam optics with real fields in compact storage rings

We analyze the proposed Karlsruhe electron storage ring for X-ray in-depth lithography using the 3rd order charged particle beam transport code MARYLIE 3.0. The ring features four 90° superconducting bending magnets. A numerical calculation of their field provides the longitudinal dependence of the multipole expansion coefficients. These are used by the code SCB to compute the Lie algebraic transfer map. Subsequent particle tracking with MARYLIE is employed to find dynamic apertures. Two different magnet designs which both lead to satisfactory dynamic apertures are presented.     

Transportation interface facilities design using interactive high-level computer graphics

A prototype pedestrian facilities design system is described. The design system exploits the capabilities of an intelligent high-resolution vector graphics workstation which features a highly interactive computer graphics environment. A summary of historical developments in pedestrian facility design and graphics workstation architecture is presented, followed by a discussion of the stochastic model and interactive computer graphics features utilized by a prototype facilities design system. Potential applications of such a design system are discussed, and promising areas of future development are outlined.