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41.
一种基于拍卖理论的移动Agent资源分配模型 总被引:1,自引:0,他引:1
描述了 1种以区间值为价格的移动 Agent资源底价密封拍卖模型 ,并赋予资源所有者参与价格制定的权利 相似文献
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中国海域的天然气水合物资源 总被引:12,自引:7,他引:5
天然气水合物是甲烷等天然气在高压、低温条件下形成的冰状固体物质。据估算,全球天然气水合物中碳的含量等于石油、煤等化石能源中碳含量的2倍。在人类面临化石能源即将枯竭的时候,各国科学家和政府都把目光投向这一未来能替代化石能源的新能源。新生代构造演化历史、沉积条件、沉积环境等显示,南海具有生成和蕴藏巨大天然气水合物资源的条件;南海海域的地震反射剖面多处显示存在BSR反射波;2007年已钻探见到水合物样品。东海冲绳海槽在第四纪的沉积速率高(10~40cm/ka),槽坡存在泥底辟构造和断裂活动,从上新世以来发生过两次构造运动,这些对天然气水合物的形成是十分有利的;因此,中国海域的天然水合物资源是十分丰富的,在不远的将来它可能成为新的替代能源。 相似文献
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A. Shamshad C.S. LeowA. Ramlah W.M.A. Wan HussinS.A. Mohd. Sanusi 《International Journal of Applied Earth Observation and Geoinformation》2008
The study evaluated the performance and suitability of AnnAGNPS model in assessing runoff, sediment loading and nutrient loading under Malaysian conditions. The watershed of River Kuala Tasik in Malaysia, a combination of two sub-watersheds, was selected as the area of study. The data for the year 2004 was used to calibrate the model and the data for the year 2005 was used for validation purposes. Several input parameters were computed using methods suggested by other researchers and studies carried out in Malaysia. The study shows that runoff was predicted well with an overall R2 value of 0.90 and E value of 0.70. Sediment loading was able to produce a moderate result of R2 = 0.66 and E = 0.49, nitrogen loading predictions were slightly better with R2 = 0.68 and E = 0.53, and phosphorus loading performance was slightly poor with an R2 = 0.63 and E = 0.33. The erosion map developed was in agreement with the erosion risk map produced by the Department of Agriculture, Malaysia. Rubber estates and urban areas were found to be the main contributors to soil erosion. The simulation results showed that AnnAGNPS has the potential to be used as a valuable tool for planning and management of watersheds under Malaysian conditions. 相似文献
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Jianqiang Ren Zhongxin Chen Qingbo Zhou Huajun Tang 《International Journal of Applied Earth Observation and Geoinformation》2008,10(4):403
The significance of crop yield estimation is well known in agricultural management and policy development at regional and national levels. The primary objective of this study was to test the suitability of the method, depending on predicted crop production, to estimate crop yield with a MODIS-NDVI-based model on a regional scale. In this paper, MODIS-NDVI data, with a 250 m resolution, was used to estimate the winter wheat (Triticum aestivum L.) yield in one of the main winter-wheat-growing regions. Our study region is located in Jining, Shandong Province. In order to improve the quality of remote sensing data and the accuracy of yield prediction, especially to eliminate the cloud-contaminated data and abnormal data in the MODIS-NDVI series, the Savitzky–Golay filter was applied to smooth the 10-day NDVI data. The spatial accumulation of NDVI at the county level was used to test its relationship with winter wheat production in the study area. A linear regressive relationship between the spatial accumulation of NDVI and the production of winter wheat was established using a stepwise regression method. The average yield was derived from predicted production divided by the growing acreage of winter wheat on a county level. Finally, the results were validated by the ground survey data, and the errors were compared with the errors of agro-climate models. The results showed that the relative errors of the predicted yield using MODIS-NDVI are between −4.62% and 5.40% and that whole RMSE was 214.16 kg ha−1 lower than the RMSE (233.35 kg ha−1) of agro-climate models in this study region. A good predicted yield data of winter wheat could be got about 40 days ahead of harvest time, i.e. at the booting-heading stage of winter wheat. The method suggested in this paper was good for predicting regional winter wheat production and yield estimation. 相似文献
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线性最小二乘估计在对非线性函数进行线性近似的过程中会产生模型误差,而一些非线性参数估计方法可能因为函数复杂而难以求导,法方程系数矩阵秩亏或呈病态矩阵时难以求解,非线性迭代解法有时对初始值的选择存在依赖性,不恰当的初始值会导致迭代无法收敛。针对这些问题,引入了模拟退火算法,介绍了该算法的基本原理、计算步骤和收敛性,并以3个控制网平差应用为例,说明该算法具有无需求导求逆,简洁实用,易于编程等优势,并能实现全局优化,获得高精度的平差结果。 相似文献
50.
This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied
long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects:
first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions
plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the
growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones,
a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding
regional income distribution dynamics.
相似文献
Manfred M. FischerEmail: |