运用禁忌搜索算法进行高光谱影像降维的研究

本文在分析了传统降维方法所面临问题的基础上，将禁忌搜索算法引入到高光谱影像的特征选择研究，指出由于禁忌搜索算法所具有的良好全局寻优能力，因而在该类影像的降维研究中有着广阔的应用前景。针对高维光谱数据的特点，讲述了算法运行过程中需注意的若干关键问题。实验表明，将禁忌搜索算法获取的波段进行高光谱影像分类，在求解的时间上和分类结果的精度都可达到令人满意的效果。     

Shaking table model test on Shanghai World Financial Center Tower

The height of 101‐storey Shanghai World Financial Center Tower is 492m above ground making it possible the tallest building in the world when completed. Three parallel structural systems including mega‐frame structure, reinforced concrete and braced steel services core and outrigger trusses, are combined to resist vertical and lateral loads. The building could be classified as a vertically irregular structure due to a number of stiffened and transfer stories in the building. Complexities related to structural system layout are mainly exhibited in the design of services core, mega‐diagonals and outrigger trusses. According to Chinese Code, the height 190 m of the building clearly exceeds the stipulated maximum height of for a composite frame/reinforced concrete core building. The aspect ratio of height to width also exceeds the stipulated limit of 7 for seismic design intensity 7. A 1/50 scaled model is made and tested on shaking table under a series of one and two‐dimensional base excitations with gradually increasing acceleration amplitudes. This paper presents the dynamic characteristics, the seismic responses and the failure mechanism of the structure. The test results demonstrate that the structural system is a good solution to withstand earthquakes. The inter‐storey drift and the overall behaviour meet the requirements of Chinese Design Code. Furthermore, weak positions under seldom‐occurred earthquakes of seismic design intensity 8 are found based on the visible damages on the testing model, and some corresponding suggestions are proposed for the engineering design of the structure under extremely strong earthquake. Copyright © 2006 John Wiley & Sons, Ltd.     

Quasar redshift distribution and selection effects

With the Hewitt-Burbidge catalogue of quasars as our sample, separately for 3 sets of respectively 7, 11, and 13 spectral lines as the “key lines” in the identification of quasar redshifts, we derive the redshift distribution arising from the identification of the lines. A comparison between the calculated and observed distributions shows that 1) the two are clearly correlated, with a correlation coefficient of 0.56. 2) Similar peaks are present in both in the z-intervals 0.2 – 0.4, 0.8 – 0.9, 1.4 – 1.5, and particularly around 1.95, as well similar valleys at 0.1 and 1.5 – 1.8. 3) Both rise or fall together at z = 0.2, 0.3, 0.4, 0.8, 1.9, 1.4, 1.5, 1.6 and 1.7. It thus appears that selection effects play an important role in the redshift distribution of the quasars.     

高空资料质量问题的原因分析

分析了山东省高空资料审核中出现的问题及原因,并对特殊情况和异常数据提出了处理办法。     

中国地面月气候资料质量控制方法的研究

由于气象台站信息变化以及观测规范的频繁变动, 使中国地面气象资料序列比较复杂。该文在分析中国地面历史气象资料中可能存在的非均一性和错误性、研究月气候资料序列存在的可能分布状态的基础上, 提出了中国地面月气候资料质量控制技术。通过分析认为, 中国地面月气候资料的质量控制, 应把下列3种方式结合起来, 进行综合质量检测:①把12个月的气候资料序列联合起来, 进行长时间连续性错误资料检测; ②把时间序列变换为接近正态分布的均一序列后, 进行时间域和空间域的奇异值检测; ③对检测出的连续性可疑资料和单个数据点的奇异值进行人工分析辨别。利用上述质量控制方法, 对1971—2000年中国地面700多基准基本站月统计气候资料进行了质量检查, 最后介绍了质量检查结果。     

Solving Three Types of Satellite Gravity Gradient Boundary Value Problems by Least-Squares

The principle and method for solving three types of satellite gravity gradient boundary value problems by least-squares are discussed in detail. Also, kernel function expressions of the least-squares solution of three geodetic boundary value problems with the observations {Γ zz },{Γ xz , Γ yz} and {Γ xx -Γ yy ,2 Γxy}are presented. From the results of recovering gravity field using simulated gravity gradient tensor data, we can draw a conclusion that satellite gravity gradient integral formulas derived from least-squares are valid and rigorous for recovering the gravity field.     

龙岩红尖山广电微波中转站防雷保护设计

简要介绍了龙岩市红尖山广电微波中转站的结构和防雷现状.此高山广电微波中转站地区雷暴次数多,强度大,上行雷、下行雷均可能发生,土壤电阻率高,电源多为架空线进户,雷电波侵入机率高、强度大,针对上述特点,以国家防雷标准为依据,考虑台站的地理地形环境的影响,对整个微波站中转系统提出了综合防雷保护方法,为解决高山广电微波站的雷电防护问题提供参考.     

川西康定老榆林高温地热地球物理特征与形成机制研究

川西地区地热资源丰富,康定地区由中谷至老榆林一线,发育有多个高温地热田。通过对川西地区重磁资料和地质构造背景的分析,总结川西地区地热的分布特征,重点应用宽频大地电磁测深、音频大地电磁测深剖面及钻井资料,对研究区不同深度和尺度的地热要素进行探讨。研究结果表明：大量地热点发育在断裂附近,呈现出明显的空间分布相关性。在鲜水河断裂带下方的部分熔融体为本区高温地热田提供了主要热源。老榆林地热田主要受南北向深大断裂的次级构造和与之交错的东西向断裂构造控制,断裂破碎带构成热储,是深部热水上涌的通道。本文探讨了川西康定地区多尺度地球物理结构,高温地热资源的形成和分布与多要素耦合密切相关,构建出本区三维的地热地质模型。川西康定地区具有良好的高温地热水形成条件,通过地热资源开发,可促进川西地区社会经济发展。     

Impacts of a Wave Farm on Waves,Currents and Coastal Morphology in South West England

This study investigates impacts of a wave farm on waves, currents and coastal morphology adjacent to the wave farm, which is located in the Southwest of England (the Wave Hub). In this study, we focus on the interaction between waves and tides due to the presence of the wave farm and its effects on wave radiation stresses, bottom shear stresses and consequently on the sediment transport and the coast adjacent to the wave farm, using an integrated numerical modelling system. The modelling system consists of the near-shore wave model SWAN, the ocean circulation model ROMS and a sediment transport model for morphological evolution. The results show that tidal elevation and tidal currents can have a significant effect on waves and that tidal forcing and waves have a significant effect on bottom shear stresses. Waves can impact on the processes related to the bottom boundary layer and mixing intensity in the water column. The wave farm has an impact on the gradients of radiation shear stresses and bottom shear stresses that modify current speeds and wave heights, which in turn impact on the near-shore sediment transport and the resulting morphological changes. Bed load transport rates show a decrease when the wave farm is present, even during storm conditions. The results highlight the importance of the interactions between waves and tides when modelling coastal morphology with presence of wave energy devices.     

Changes in Regional Heavy Rainfall Events in China during 1961–2012

A new technique for identifying regional climate events, the Objective Identification Technique for Regional Extreme Events(OITREE), was applied to investigate the characteristics of regional heavy rainfall events in China during the period1961–2012. In total, 373 regional heavy rainfall events(RHREs) were identified during the past 52 years. The East Asian summer monsoon(EASM) had an important influence on the annual variations of China's RHRE activities, with a significant relationship between the intensity of the RHREs and the intensity of the Mei-yu. Although the increase in the frequency of those RHREs was not significant, China experienced more severe and extreme regional rainfall events in the 1990 s. The middle and lower reaches of the Yangtze River and the northern part of South China were the regions in the country most susceptible to extreme precipitation events. Some stations showed significant increasing trends in the southern part of the middle and lower reaches of the Yangtze River and the northern part of South China, while parts of North China, regions between Guangxi and Guangdong, and northern Sichuan showed decreasing trends in the accumulated intensity of RHREs.The spatial distribution of the linear trends of events' accumulated intensity displayed a similar so-called "southern flooding and northern drought" pattern over eastern China in recent decades.