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灰色系统预测模型的修正研究——以芜湖市耕地为例 总被引：1，自引：0，他引：1
针对GM(1,1)模型预测的不足,对其进行修正得到修正模型,并利用芜湖市耕地变化进行实例验证和应用。结果表明:1)应用灰色预测的修正模型对耕地变化进行预测比直接应用灰色预测模型更精确;2)分段建模和建立灰色—马尔柯夫模型是从两个不同的角度对GM(1,1)模型进行修正,但两者可以相互结合,使预测结果更准确。3)建立灰色—马尔柯夫模型可以避免其他多种影响因素,更具科学性和实用性。 相似文献
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提高粮食产量预测精度是科学编制土地利用总体规划的重要课题。该文首先运用灰色关联分析方法对影响粮食产量的因素做出关联因子排序,分析表明粮食单产对粮食总产量的影响最大,粮食作物播种面积次之。其次在灰色关联分析的基础上选取主要影响因子,通过比较线性回归模型、灰色GM(1,1)模型和灰色多元线性回归组合模型的预测结果,得到灰色多元线性回归组合模型预测结果最佳。 相似文献
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灰色GM(1,1)残差修正模型在滑坡预测中的对比应用 总被引：2，自引：0，他引：2
在传统GM(1,1)模型的基础上,经过不同方式的残差修正,分别建立了一阶残差修正GM(1,1)模型和二阶残差修正GM(1,1)模型。根据滑坡的监测资料,对变形曲线为光滑型滑坡(如黄龙西村滑坡、某滑坡)和阶跃型滑坡(如新滩滑坡、洒勒山新滑坡)分别建立了传统GM(1,1)模型和一阶、二阶残差修正模型,并对不同滑坡各模型的预测精度进行了分析比较。结果表明,残差修正GM(1,1)模型的预测精度明显高于传统GM(1,1)模型的预测精度。对变形曲线为光滑型的滑坡,二阶残差修正GM(1,1)模型的预测精度一般高于一阶残差修正GM(1,1)模型的预测精度;对变形曲线为阶跃型的滑坡,一阶残差修正GM(1,1)模型的预测精度高于二阶残差修正GM(1,1)模型的预测精度。 相似文献
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《干旱区地理》2016,(2)
径流过程具有随机和灰色特征。基于此,将Markov预测与灰色GM(1,2)预测相结合,提出了GM(1,2)-Markov中长期河流年径流量预测模型。通过对黑河正义峡、莺落峡水文站65 a(1949-2014年)的年径流量资料分析,将莺落峡年径流量作为GM(1,2)预测的相关因素数据列,以1990-2009年的数据建立正义峡年径流量GM(1,2)-Markov模型,以2010-2014年的年径流量进行模型验证。结果表明:莺落峡、正义峡年径流量具有较强的相关性;建立的正义峡年径流量预测模型精度为83.65%;预测未来5 a的径流量,预测精度达到了97.12%;GM(1,2)-Markov、GM(1,1)和GM(1,2)模型的模型精度都符合建模的要求,但GM(1,2)-Markov模型的预测精度明显高于GM(1,1)模型和GM(1,2)模型。GM(1,2)-Markov模型为河流径流量的中长期预测提供了一种新方法。 相似文献
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基于RAGA-BP神经网络模型的三江平原地下水资源预测研究 总被引：4，自引：1，他引：3
采用基于实数编码的加速遗传算法(RAGA)代替传统的最小二乘法以优化GM(1,1)模型参数,并与BP人工神经网络相组合,形成了基于RAGA的等维灰色递补BP神经网络预测模型.运用此模型对三江平原创业农场地下水埋深进行动态预测,BP神经网络结构确定为3:12:3,预测结果的相对误差只有2.33%,与传统的GM(1,1)模型和BP神经网络模型预测结果相比,预测精度显著提高.通过此模型预测,从2007年到2012年,该地区地下水平均年下降0.3 m. 相似文献
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云南省粮食供需安全状况及趋势研究 总被引：5，自引：0，他引：5
通过对云南省近18年来粮食生产与需求进行对比,定量分析了当前云南省粮食供需状况,并在此基础上通过灰色系统GM（1,1）模型预测2010～2030年粮食产量,同时参照云南省的权威人口预测数据,对未来云南省粮食供需趋势进行预测。研究表明：在未来20多年内,云南省土地提供的粮食能基本满足全省居民温饱型的粮食消费水平,距小康型粮食消费水平有一定差距,达到富裕型粮食消费水平的可能性很小。根据研究结论和目前云南省粮食供需状况,提出了相关解决云南省粮食产能安全的对策和建议。 相似文献
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基于支持向量回归机的耕地保有量组合预测 总被引：1，自引：0，他引：1
赖红松 《地理与地理信息科学》2011,27(2):56-60
为提高耕地保有量预测精度,将灰色预测GM(1,1)模型、动力预测模型、BP网络预测模型和加权支持向量回归机预测模型相结合,建立了基于支持向量回归机的耕地保有量组合预测模型,并将其用于温州市耕地保有量预测。结果表明,该模型比任一单一预测模型精度更高,可用于耕地保有量预测。 相似文献
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GM（1，1）优化模型在滑坡预测预报中的应用 总被引：13，自引：3，他引：13
灰色模型在社会科学、自然科学的许多方面已得到广泛的应用，并取得了一系列重大成果。在斜坡(滑坡)地质灾害研究方面，灰色模型多用于斜坡(滑坡)变形的中长期预测预报，且精度较高；但对滑坡短临预测预报精度较差，甚至不能适用，有待改进。滑坡变形预测预报的实际算例表明，以优化灰色模型背景值为基础的优化GM(1，1)模型。具有对建模结果进行优化的能力，即能用于斜坡变形的中长期预测预报，又能适于滑坡短临预测预报。且都能获得较高的模拟和预测精度。应用传统线性GM(1，1)模型和非线性Verhulst模型进行对比分析，检验了优化GM(1，1)模型的正确性和较广泛的适用性。 相似文献
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为提高原始数据呈非线性、随机性变化、样本量较小时城市耕地面积的预测精度,将无偏GM(1,1)模型与广义回归神经网络相结合,建立了基于灰色广义回归神经网络的城市耕地面积预测模型,并将其应用于平顶山市耕地面积预测,结果表明该模型精度高,具有一定的应用价值。 相似文献
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河南省耕地和粮食灰色关联分析 总被引：18，自引：2，他引：18
收集整理 1 949～ 1 999年河南省耕地、人口、粮食和复种指数等资料 ,定量分析耕地的数量变化、质量状况和耕地减少的形式 ,用一元线性回归法预测人口变化趋势 ,对粮食生产与其影响因素进行灰色关联分析和相关分析 ,提出外延式和内涵式开发耕地资源增产粮食的途径 ,对粮食单产和耕地复种指数进行回归分析. 相似文献
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Spatial-temporal pattern changes of main agriculture natural disasters in China during 1990-2011 总被引：1，自引：0，他引：1
Xindong DU Xiaobin JIN Xilian YANG Xuhong YANG Xiaomin XIANG Yinkang ZHOU 《地理学报(英文版)》2015,25(4):387-398
China is a disaster prone country, and a comprehensive understanding of change of disasters is very important for China’s agricultural development. In this study, statistical techniques and geographic information system tools are employed to quantify the main agriculture disasters changes and effects on grain production in China during the period of 1990-2011. The results show that China’s grain production was severely affected by disasters including drought, flood, hail, frost and typhoon. The annual area covered by these disasters reached up to 48.7×106 ha during the study period, which accounted for 44.8% of the total sown area, and about 55.1% of the per unit area grain yield change was caused by disasters. In addition, all of the disasters showed high variability, different changing trends, and spatial distribution. Drought, flood, and hail showed significantly decreasing trends, while frost and typhoon showed increasing trends. Drought and flood showed gradual changes and were distributed across the country, and disasters became more diversified from north to south. Drought was the dominated disaster type in northern China, while flood was the most important disaster type in the southern part. Hail was mainly observed in central and northern China, and frost was mainly distributed in southern China. Typhoon was greatly limited to the southeast coast. Furthermore, the resilience of grain production of each province was quite different, especially in several major grain producing areas, such as Shandong, Liaoning, Jilin and Jiangsu, where grain production was seriously affected by disasters. One reason for the difference of resilience of grain production was that grain production was marginalized in developed provinces when the economy underwent rapid development. For China’s agricultural development and grain security, we suggest that governments should place more emphasis on grain production, and invest more money in disaster prevention and mitigation, especially in the major grain producing provinces. 相似文献
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1IntroductionThe quantity and quality of cropland guarantees the grain production (Feng, 2000), and the essence of cropland security is food security. Cropland security means the stability of total quantity of cropland, which also means stable quality, potential productivity and regional balance (Feng, 2000). With the development of urbanization and industrialization, more and more cropland is encroached, especially the cropland with great market-value (Cai, 2000; Ge, 2002; Richard, 2002), w… 相似文献
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The quantity and quality changes of cropland in Jilin province are analyzed by combining the statistics from 1949 to 1999 and land-use maps interpreted from TM images in 1986 and in 2000. In general, the decreasing trend of the cropland in Jilin province was derived from the statistic data in 1949-1999. While since 1983, the cropland area has increased slightly, because of the conversion from other land-use types to cropland. It is showed that the net increase of cropland was about 43.40×104 ha. While the quality change of the cropland can be seen from that mainly caused by the conversion from forestland, grassland to cropland and the change mainly took place in the west, where it is ecologically fragile. According to the spatial distribution model, the centroids' move of the cropland and the grain production are calculated, whose directions are not consistent. The impact of the dynamic change of the cropland on food security is further analyzed. 相似文献
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在我国改革开放政策实行较早的广东珠江三角洲地区，我们对地处西南部的新会市进行了为期两年的全面、典型抽样调查。发现全市的耕地面积和播种面积呈下降趋势，单产虽有较大幅度的增长但粮食总产量的增长缓慢，速度低于全市总人口的自然增长率，因此人均粮食产量呈下降趋势。根据建立的灰色ＧＭ（１，１）模型预测，新会市２０１０年人均耕地面积只有０．０２５ｈｍ＾２，在“人均４分保命田”之下。因此，本文对该地区作出的粮食及 相似文献
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东北三省农业旱灾风险评估研究 总被引：3，自引：1，他引：2
气候变化背景下,干旱对农业生产造成的损失已不容忽视。明晰粮食主产区面临的旱灾风险特征有利于保障中国粮食生产安全。东北三省是中国最重要的粮食主产区之一,明晰该地区的农业旱灾特征对农业生产具有十分重要的作用。基于自然灾害系统理论针对东北三省构建了农业旱灾风险评估模型,并在县市尺度对不同等级农业旱灾风险进行了分区。研究中分别从省份尺度和县市尺度对农业旱灾危险性、暴露性、脆弱性、抗旱能力及农业旱灾综合风险进行评估。结果表明：省份尺度上,农业旱灾综合风险由高到低分别为黑龙江省、吉林省及辽宁省。其中危险性年际间差异明显,暴露性则相对稳定。2010-2015年间脆弱性呈增加趋势,三省抗旱能力均随年际变化而波动。空间范围上,东北三省农业旱灾风险由南向北递增。农业旱灾综合风险等级上,中级及其以上级别县市占对应省份的比例由高到低分别为黑龙江省（75.81%）、吉林省（41.30%）与辽宁省（0%）。值得注意的是,农业旱灾综合等级最高的地区主要集中在三江平原及松嫩平原区。 相似文献
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Grain production patterns are the basis of a nation’s food security. Since China’s reform and opening-up began in 1978, China’s urbanization process, driven by rapid social and economic development, has accelerated steadily. During this time, the dietary structure of urban and rural Chinese has also changed significantly. Accordingly, grain production patterns have undergone major changes. First, traditional grain production patterns in the north and the south have changed, and the food production center has shifted toward the north. In 1980, the grain yield of southern provinces accounted for 60% of China’s total, while that of northern provinces accounted for 40%. In 2015, the grain yield of southern provinces accounted for 56% of the total, while that of northern provinces accounted for 44%. Second, grain production by regions of the country is “shrinking in the east but expanding in the central regions,” meaning that grain production in eastern coastal provinces has decreased significantly, while that in the central region has expanded. The proportions of the nation’s total grain production from the eastern, central and western regions were 38%, 36% and 26%, respectively, in 1980. These had changed to 27%, 46%, and 27%, respectively, in 2015. Third, the spatial centralization of grain production has increased. The total grain yield of 13 major grain-producing provinces and regions in the country accounted for 69.27% of nation’s total in 1980, and it had reached 76.18% in 2015, showing that the impact of major grain-producing areas on national food security has increased. The influence of rapid urbanization on grain production areas shows remarkable regional differences. As the level of urbanization has increased, build-up land occupies a large number of high-quality farmland, especially in east coastal provinces and thus the grain planting area decreased obviously. The effect of dietary structure changes on grain production patterns was evident in two ways. On the one hand, as dietary diversity has increased, total grain consumption has decreased. The reduction in the proportion of planting area for grain crops to total crop planting area dropped from 82% in 1980 to 68% in 2015, making this change in total grain consumption evident. On the other hand, the ratio of grain for human consumption declined as the ratio of grain consumed by animals increased. The reduction in the proportion of rice and wheat grown and an increase in the proportion of feed grain production (mostly maize) from 20% in the 1980s to 36% in 2015 makes this change in grain production and consumption evident. In the future, with the establishment of national functional areas for grain production, the spatial pattern of grain production will return, while the demand for feed grains will continue to increase but with the space for expansion limited. 相似文献
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我国棉花主产省区比较优势分析 总被引：9，自引：0，他引：9
1992-1998年平均，我国12个棉花主产省（区）的粮棉单产比和植棉相对效益分别为1.94-7.24和0.95-5.41，经统计分析，这一单产比和相对效益每上升1，一个省1999年与1992年棉花产量之比就分别下降34.0个百分点、上升48.3个百分比，据此比较优势分析，在1999年我国棉花总产下调的形势下，甘肃、新疆宜保持原有产量水平、江苏、浙江、山东、河北、四川5省宜适当下调，而江西、安徽、河南、湖南、湖北5省则宜酌情处理。基于近期国际棉花市场形势的变化，作者认为，与其它省份一样，2001年甘肃、新疆的棉花产量也有较大的上调空间。 相似文献