The European system of capital cities     

Paul Claval 《GeoJournal》2000,51(1-2):73-81

Capital cities reflect the nature and organization of the states they control. Their functional role is higher in centralized systems, societies where the state is the source of all legitimacy, and countries using Continental Law. It is lower in federal systems, pillarized societies and countries, which are ruled according to a Common Law. The symbolic status of capital cities is higher when the state is the source of all legitimacy, lower in consociationalist societies. Theses processes were responsible for the development of two types of political capital cities and one type of economic and cultural capital cities during the nineteenth century. A partial standardization of the functions and statuses of capital cities occurred later. The European Union is neither a state nor a super-state since its main responsibilities are still in the economic field, it lacks a huge administrative bureaucracy and does not have definitive territorial limits. The European Union has officially three capital cities, Strasbourg, Luxembourg and Brussels. The really important one is Brussels. Its functions are nevertheless quite different from those of national capital cities during the first half of the twentieth century. European capital cities are thriving because most of them managed to become economic metropolises. The result is that the European Union has a complex and rapidly evolving system of capital cities.  相似文献   

工程反射地震非常规方法野外施工的探讨     

王者江  何樵登  田钢  曾昭发  薛建 《吉林大学学报(地球科学版)》2005,35(6):796-800

工程反射地震常规的多次覆盖系统、排列和炮点的同时滚动,导致了施工效率的低下。为解决这个问题,从共反射点原理出发,详细探讨了非常规的移动炮点的多次覆盖观测方法,并与常规的多次覆盖观测方法进行了对比。认为这种方法在提高野外施工效率的同时,也可以提高数据的信噪比和速度分析的精度,并且可兼顾折射法和多道面波的应用。  相似文献   

Geographical variation in abundance of striped and common dolphins of the western Mediterranean     

Jaume Forcada  Philip Hammond 《Journal of Sea Research》1998,39(3-4)

Line-transect data from sighting surveys conducted in the western Mediterranean (in 1991) and the Alboran Sea (in 1992) were analysed to estimate densities and numbers of striped and common dolphins in various areas of the western Mediterranean. Density of striped dolphins in the northwestern Mediterranean was estimated as 0.20 dolphins km⁻² (CV = 0.24; 95% CI = 0.12 and 0.32) and was 41% higher than in the southwestern Mediterranean, where it was estimated as 0.12 dolphins km⁻² (CV = 0.38; 95% CI = 0.05 and 0.25). The highest densities were observed in the Liguro–Provençal basin, with 0.24 dolphins km⁻² (CV = 0.26; 95% CI = 0.14 and 0.40), and the Alboran Sea, with 0.20 dolphins km⁻² (CV = 0.33; 95% CI = 0.10 and 0.36). These areas, and especially the Ligurian Sea, appear to be the most productive in terms of the food consumed by striped dolphins. Common dolphins were abundant only in the Alboran Sea with an estimated density of 0.16 dolphins km⁻² (CV = 0.40; 95% CI = 0.08 and 0.35), scarce in the south Balearic area and almost absent in the northwestern Mediterranean. The magnitude of the dolphin by-catch in fishing operations in the Alboran Sea and other areas stresses the need for further assessment of densities and numbers, notably in the Alboran Sea and the North African Mediterranean waters.  相似文献   

东洞庭湖4种濒危鹤类近30年种群动态及栖息地景观格局变化   总被引：1，自引：1，他引：0  

周延  靖磊  贾亦飞  雷刚  姚毅  吕偲  陈安平  雷光春 《湖泊科学》2019,31(5):1415-1423

东洞庭湖是4种濒危鹤类：白头鹤（Grus monacha）、白枕鹤（G.vipio）、白鹤（G.leucogeranus）和灰鹤（G.grus）的越冬地,但尚无东洞庭湖越冬鹤类种群动态及栖息地变化的系统研究.本研究调查收集了近30年来东洞庭湖4种鹤类的种群状况,并选取相应越冬季的东洞庭湖卫星图片,提取不同时期东洞庭湖湿地景观格局数据,分析鹤类种群动态与湿地景观格局之间的关联.结果表明：近30年来,东洞庭湖4种濒危鹤类种群数量均呈不同程度的下降.目前4种鹤类集中分布于采桑湖、丁字堤一带,灰鹤种群数量尚维持有二百余只,而白头鹤、白枕鹤和白鹤仅有不足10只的零星分布.1999-2000年后东洞庭湖水域及泥滩面积迅速下降并快速破碎化是导致鹤类种群下降的重要原因.未来应从保护及恢复东洞庭湖鹤类栖息地入手,加大鹤类保护,逐渐恢复东洞庭湖鹤类种群.  相似文献   

浅谈计算机视觉与数字摄影测量   总被引：2，自引：0，他引：2  

张梅  文静华 《地理空间信息》2010,8(2):15-17,20

计算机视觉技术集数字图像处理、应用数学、模式识别及人工智能等知识于一体,其应用已经涉及到计算机图形学、图像处理与分析、机器人学等领域。数字摄影测量技术是测绘学科的一个分支,数字摄影测量已经进入计算机视觉的领域。文中简要地回顾了计算机视觉技术的发展史,主要介绍了计算机视觉与数字摄影测量的共同点及其本质差异。  相似文献   

Age characteristics of walleye pollock school echoes     

Kang  Myounghee; Honda  Satoshi; Oshima  Tatsuki 《ICES Journal of Marine Science》2006,63(8):1465-1476

  相似文献   

建筑塔机臂尖GNSS动态监测模型设计   总被引：2，自引：1，他引：1  

周命端  张文尧  马博泓  付静弘怡  罗德安 《测绘通报》2020,(8):23-27

鉴于传统的人工周期巡检方式存在诸多弊端，本文设计了一种基于卫星定位的建筑塔机臂尖动态监测模型。以GPS为例建立单历元快速定位模型，给出利用DUFCOM和DC算法相组合的整周模糊度快速确定算法（FARSE）的实现流程；提出了一种基于历元位置偏差的臂尖垂向位移监测参数及预警参数构造方法。初步试验结果表明，利用GPS单历元快速定位模型解算获得了平面精度优于2 cm、高程精度优于4 cm的定位结果；基于该定位结果，从监测参数和预警参数两个角度验证了本文模型设计的有效性。  相似文献   

双频共面合成孔径雷达海面风场反演     

艾未华  陈冠宇  戈书睿  袁凌峰  赵现斌 《遥感学报》2019,23(3):408-417

根据L/C双频共面SAR能够获取同一海域双波段电磁波后向散射系数,得到更多海洋目标特征信息的电磁散射特点,结合地球物理模型函数研究了一种新的SAR海面风场反演方法。利用L/C双频共面SAR的L和C两个波段的地球物理模型函数和后向散射系数等信息,通过地球物理模型函数联立以及构建和求解最小代价函数,直接从SAR数据本身获取海面风场信息,并借助辅助数据去除了风向的180°模糊,从而实现海面风场反演。仿真分析和海上机载同步飞行试验的研究结果表明,该方法可直接利用SAR数据本身获取精度较高的海面风速、风向;绝对辐射定标精度是决定海面风场反演精度的关键因素,海面风场反演误差随定标精度提高而减小;随着海面风速的增大,风速反演误差逐渐增大。论文提出的双频共面SAR海面风场反演方法解决了传统单波段单极化SAR海面风场反演存在的固有问题,机载同步飞行试验的海面风速和风向反演结果与调查船观测值的均方根误差分别为0.93 m/s和19.39°,可为星载SAR海面风场反演业务化和载荷研制提供支持。  相似文献   

大山包黑颈鹤国家自然保护区湿地资源现状调查及保护对策   总被引：3，自引：0，他引：3  

吴风志  王金亮  钟兴耀  范涛 《云南地理环境研究》2012,24(2):78-82,89

湿地调查是对湿地资源实施有效保护的重要前提。以地理信息技术为技术平台,开展大山包黑颈鹤国家自然保护区湿地调查,结果表明：保护区现存高山草甸等8种湿地类型,湿地总面积为3227．11hm^2;目前湿地保护主要面临水资源过度开发、过度放牧和复垦开荒等威胁,需要通过完善补偿机制、加强湿地资源管理与合理开发利用、探索人口与农业发展新模式及提升民众湿地保护意识等途径来加以保护。  相似文献   

Improving the CoLM in Taklimakan Desert hinterland with accurate key parameters and an appropriate parameterization scheme     

刘永强  何清  张宏升  艾力 《大气科学进展》2012,29(2):381-390

Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to be evaluated in-situ to improve the models. In this study, we calibrated the land-surface key parameters and evaluated several formulations or schemes for thermal roughness length (z 0h ) in the common land model (CoLM). Our parameter calibration and scheme evaluation were based on the observed data during a torrid summer (29 July to 11 September 2009) over the Taklimakan Desert hinterland. First, the importance of the key parameters in the experiment was evaluated based on their physics principles and the significance of these key parameters were further validated using sensitivity test. Second, difference schemes (or physics-based formulas) of z 0h were adopted to simulate the variations of energy-related variables (e.g., sensible heat flux and surface skin temperature) and the simulated variations were then compared with the observed data. Third, the z 0h scheme that performed best (i.e., Y07) was then selected to replace the defaulted one (i.e., Z98); the revised scheme and the superiority of Y07 over Z98 was further demonstrated by comparing the simulated results with the observed data. Admittedly, the revised model did a relatively poor job of simulating the diurnal variations of surface soil heat flux, and nighttime soil temperature was also underestimated, calling for further improvement of the model for desert regions.  相似文献