非物质文化系列专题制图方法探讨     

安兰兰  刘长虹  李仁杰  傅学庆  张军海 《测绘科学》2016,41(5):127-132

针对传统制图方法在动态制图、数据更新和地图服务等方面的不足,该文提出了一套较为系统的非物质文化专题制图设计模式:引入建库与制图一体化思想,通过建立完整的非物质文化数据库,实现了数据入库、存储与管理的一体化控制;建库数据动态派生制图数据,不仅避免了数据冗余,而且达到了一库两用的目的;基于数据库设计,运用GIS地图表达功能,实现了非物质文化专题信息可视化,并总结了可视化过程中空间尺度变换时各类地图要素的选择或约束方法。最后通过实例证明了本文方法的可行性和有效性。  相似文献   

A growth model for a hyalid amphipod Hyale perieri in the coastal water of Alexandria (Egypt)     

Zakaria H. Y  Dowidar N. M.  El-Komi M. M.  Atta M. M. 《海洋学报(英文版)》2003,22(2):221-231

Abstract-The growth rate of the hyalid amphipod Hyale perieri was studied on the bases of Ikeda'sgrowth model which is based on the inter moult period (IP) and moult increament (ΔBL). To applythis approach, laboratory experiments were carried out at three temperatures regimes (15℃, 20℃,25℃) to gain accurate data of IP and BL. The total number of specimens used in this study was 86 at15℃, 24 at 20℃ and 70 at 25℃. The number of flagellar segments of both antennae of the Hyaleperieri could not be used as an index of growth (instar criterion). The obtained results indicated that,the predicted IP of the specimens was inversely related to temperature and in good agreement with theobserved values at the experimental temperatures. IP data obtained from laboratory-reared specimes arecombined with ΔBL data to establish a growth model for Hyale perieri from its release from the mar-supium (1.64 mm BL) to the maximum size (12.67 mm BL) as a function of temperature. The maxi-mum numbers of consecutive moults  相似文献   

Multilevel Optimal Design of Prestressed Lightweight Concrete-Steel Platform Structures     

WANG  Licheng 《中国海洋工程》2002,16(1):69-78

The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. K the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms.  相似文献   

Proof of multiplicity of solutions for groundwater seepage in recharged heterogeneous unconfined aquifers          下载免费PDF全文

R.P. Chapuis 《国际地质力学数值与分析法杂志》2016,40(14):1988-2002

A new analytical proof is presented for steady‐state seepage in recharged heterogeneous unconfined aquifers. The paper also presents a detailed procedure and important rules for performing correctly numerical studies of unsaturated seepage. Once a numerical solution is calibrated with field data, using a set of spatially distributed values for hydraulic conductivity K and effective infiltration EI, any new numerical analysis with a set of αK and αEI values, where α is a constant, yields an equally good calibration. However, if the effective porosities of each layer are unchanged, the groundwater velocities are multiplied by α, whereas the travel times are divided by α, which may help to select α in order to match known travel time data. This is a clear example of multiple solutions to an inverse problem. The paper underlines the role and the need to finely mesh unsaturated zones and also contacts between layers to reach the asymptotic convergence range, as it was carried out to verify the proof and as it should be completed to study any seepage problem. A few consequences of the new analytical proof and the rigorous procedure are shown with examples. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Use of mixed bivariate distributions for deriving inter‐station correlation coefficients of rain rate     

Eunho Ha  Chulsang Yoo 《水文研究》2007,21(22):3078-3086

Even though rain rate is notorious for its spatial and temporal intermittency, its effect on the second‐order statistics of rain rate, especially the inter‐station correlation coefficients, has not been intensively evaluated before. This study has derived and compared the inter‐station correlation coefficient of rain rate for three cases of data: (1) only the positive measurements at both locations; (2) the positive measurements at either one or both locations; (3) all the measurements including zero measurement at both locations. For these three cases, the inter‐station correlation coefficients are analytically derived by applying the mixed bivariate log‐normal distribution. As an application example, the model parameters are estimated using the rain rate data collected at the Geum River basin, Korea, and the resulting inter‐station correlation coefficients are evaluated and compared with those estimated by applying the Gaussian distribution. We could find that highly biased inter‐station correlation coefficients are unavoidable when simply estimating them under the assumption of Gaussian distribution, or even when using the log‐transformed rain rate data. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Tidal variation in a rocky inter‐tidal fish population: the case of white seabream Diplodus sargus juveniles          下载免费PDF全文

Ana Ribeiro Gonçalves  Liliana de Sousa  Pedro Duarte‐Coelho  Vitor Carvalho Almada 《Marine Ecology》2015,36(4):1468-1471

The rocky inter‐tidal habitat is a harsh and fluctuating environment, subject to frequent disturbances. Field observations of juvenile white seabream Diplodus sargus in inter‐tidal rocky habitats were conducted to analyse the spatial distribution and feeding activity of this species in relation to the tidal cycle. The depth at which fish were observed did not change in most tidal phases while feeding activity changed with tidal level, showing the occurrence of tidal migrations and that feeding may be limited by habitat availability in shallow waters and thus be dependent on tidal changes. The present results show the exploitation of available feeding areas in the rocky inter‐tidal by juvenile white seabream, which corroborates the importance of these habitats for the first developmental stages of this fish species.  相似文献   

NUMERICAL EXPERIMENTS ON MULTI-LEVEL STATISTICAL ESTIMATION OF DYNAMIC BALANCE CONSTRAINTS IN GRAPES-3DVAR     

王瑞春  龚建东  张林  薛谌彬 《热带气象学报(英文版)》2015,21(4):417-427

This paper further explores the estimating and expressing of dynamic balance constraints using statistical methods in GRAPES-3DVAR (Version GM). Unlike the single-level scheme which only considers the coupling between mass and wind at one level, the multi-level scheme considers the coupling between their vertical profiles and calculates the balanced mass field at each layer using the rotational wind at all model levels. A reformed ridge regression method is used in the new scheme to avoid the multicollinearity problem and reduce the noises caused by unbalanced mesoscale disturbances. The results of numerical experiments show that the new scheme can get more reasonable vertical mass field, reduce the magnitude of the adjustment by the initialization, and improve the potential temperature analysis performance. Furthermore, the results of forecast verification in January (winter) and July (summer) both confirm that the new scheme can significantly improve the temperature forecast accuracy and bring slight positive effects to the pressure and wind forecast.  相似文献   

综合线面特征分布的点目标多尺度聚类方法     

余莉  甘淑  袁希平  杨明龙 《测绘学报》2015,44(10):1152-1159

考虑空间数据分布的复杂性与不连续性,提出了一种点目标聚类方法。算法利用全要素Voronoi图准确识别与表达点目标与线面实体的空间相关性;根据点目标位置分布特征计算面积阈值来控制聚类的粒度,同时以空间尺度变化下面积阈值的恒定作为判断尺度收敛的条件,实现点目标的多尺度划分,时间复杂度为O(nlogn)。经试验验证,聚类尺度随点目标分布特征自适应收敛,算法无须自定义参数,能够有效地发现受线面目标约束的任意形态点目标集群,对异常值处理稳健。  相似文献   

近50 a来祁连山及河西走廊极端气候的时空变化研究   总被引：1，自引：0，他引：1       下载免费PDF全文

贾文雄 《干旱区地理》2012,35(4):559-567

 在全球变暖背景下,极端气候发生的频率增大,气象灾害造成的损失也随之增加。利用20个气象站1960-2009年的日平均气温和日降水量资料,运用线性趋势法、Spline空间插值法、Morlet小波分析法,对祁连山及河西走廊极端气候的时空变化特征进行了研究。结果表明：极端高温天数呈显著增加趋势,年际变化率为0.79d/a,20世纪90年代中后期之后极端高温天气发生的频率较高;极端低温天数呈显著减少趋势,年际变化率为-0.54d/a, 80年代中后期以来极端低温天气发生的频率较低;极端降水天数也呈显著增加趋势,年际变化率为0.02d/a,70年代中后期之后极端降水天气发生的频率较高。极端气温和降水的年际变化幅度存在区域差异,南部山区比走廊平原对全球气候变暖的响应敏感。极端高温天数和极端低温天数在8a、22a左右周期变化明显,其中22a是第一主周期;极端降水天数在6a、10a、22a左右周期变化明显,其中22a是第一主周期;从22a的周期变化推测,2010年以后11a左右极端高温天数偏少,极端低温天数偏多,极端降水天数偏少。  相似文献   

基于土地供需关系对北京城市拓展中土地资源约束条件的初步分析(英文)     

樊杰  张有坤 《资源与生态学报(英文版)》2012,(3):253-261

土地资源作为重要的自然环境载体,对城市发展既起到了支撑作用,同时也会制约城市的盲目扩张。本文以北京市为例,从供给与需求两方面,总结了北京城市发展的土地资源约束特征,初步测算了其城市空间的上限规模。一方面,分析了产业用地和生活居住用地等土地资源需求主导因素的特征和变化趋势,基于不同的土地利用效率情景,初步测算得出北京城市发展对土地资源的需求规模区间为[1596 km2,2846 km2]。另一方面通过分析北京地区农业空间、生态空间及其他用地空间的占用、消耗特征,测算得出不同情景下土地资源对北京城市发展的供给规模区间为[1673 km2,2821 km2]。可以看出,当前北京城市发展的土地需求明显大于供给。同时指出了未来北京城市拓展受到土地资源供给的总量约束、空间约束及城市功能定位决定的用地结构性约束等限制。最后尝试提出解决当前城市发展面临的资源环境瓶颈和城市病等问题的思路。  相似文献