共查询到20条相似文献，搜索用时 203 毫秒
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Bastd on dealing with the initial data of the gas emissing quantity of mining coal face by natural logarithm,the improved grey model(1,1) is built.The improved Grey Markov prediction mode is built through uniting the improved grey model(1,1) and the Markov mode.Comparing the fitting precision of the improved grey model(1,1),the Grey Markov prediction mode and the improved Grey Markov prediction mode respectively through actual survey data in scene,it shows that the precision of the improved Grey Markov prediction mode is the best of the three and its result is correct and reliable,having certain general applicability. 相似文献
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初霜冻害是影响宿州市秋收作物收成的重要因素。根据季节事件灰预测和多模型离散覆盖机理,创建不同零起点的灾变子序列并建立多个GM(1,1)模型,按照灰关联度择优选模,利用新息或灰数依次递补,对初霜期10月23日出现年份进行预测。提出按照频次对多模型离散覆盖进行白化以确定最有可能出现的年份,经预报检验效果较好,对初霜期的长期预测有一定的参考价值。 相似文献
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为预测未来5年（2011-2015年）中国水产品的年总产量。本研究基于灰色系统理论和方法,首先分别构建常规GM(1,1)模型和灰色新陈代谢GM(1,1)模型,对2006-2009年中国水产品年总产量进行预测分析并比较两种模型的预测精度。然后选择预测精度较高的模型对未来5年中国水产品年总产量进行预测研究。常规GM(1,1)模型和灰色新陈代谢GM(1,1)模型对2006-2009年中国水产品年总产量预测的精度比较显示：灰色新陈代谢GM(1,1)模型预测精度更高,预测误差更小,更适用于水产品年总产量的预测研究。因此,选择灰色新陈代谢GM(1,1)模型对中国未来5年水产品年总产量进行预测,即2011-2015年中国水产品年总产量将分别达到5532.333、5746.315、5972.634、6202.738、6443.838万t,年均增长率达到3.7%,远高于《全国渔业发展第十二个五年规划（2011-2015年）》设定年均增长2.2%的目标。本研究结果表明：灰色新陈代谢GM(1,1)模型适用于水产品产量预测的研究;2011-2015年中国水产品总产量完全可以实现渔业“十二五”规划设定目标。 相似文献
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Jiang Cheng- yi 《保鲜与加工》1996,(3):116-122
This paper presents objectives of study of grey system and the GM(1,1)grey forecast model is introduced.A new forecasting method was introduced which combined merits of both grey GM(1,1)forecast and Markov forecast overcome their shortcomings and increased precision of forecast.Finaly, an example for application was given. 相似文献
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[目的]研究旨在分析甘肃省近十一年的生态安全状况并预测其发展趋势,以期为改善甘肃省生态环境提供理论指导与借鉴。[方法]基于驱动力-压力-状态-响应(DPSR)模型,构建出甘肃省生态安全预警评价指标体系,并运用熵值法对其2005-2015年的生态安全进行预警分析,最后运用GM(1,1)灰色预测模型预测2018-2022年的生态安全变化趋势。[结果、结论]研究表明:2005-2015年甘肃省生态安全指数从0.4103增加到0.5967,呈波动上升趋势,生态安全等级从Ⅲ级到Ⅱ级再到Ⅲ级,呈现“U”型态势,说明甘肃省生态环境在经历了恶化之后得到了一定程度的改善;灰色预测分析得出2018-2022年生态安全指数分别为0.6344、0.6592、0.6859、0.7148、0.7458,表明甘肃省生态安全状况仍将保持向好的趋势。 相似文献
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The paper depends on the new three theories(theory of dissipative structure.catastrophe theory and synergetics)as a guide,and establishes a developmental strategy planning forthe circumjacent reservoir regin of Longtan hydropower project which is the dragon head station often-cascade development along the Red Water Rlver,and adopts grey systems theory to predict theeconomic development of the reservoir region, The computational results show that the grey predic-tion model,the theory and methods of grey systems applying to economic system prediction are effi-clent. 相似文献
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To solve the problem of poor prediction accuracy of GM(11)model when the data are discretebased on the sign of residual error modification value of prediction value being determined by Markvo chaina residual error modification is presented.The grey residual error GM(11)model based on Markvo is constructed through the modification of simulation value and prediction value obtained from GM(11)model.The prediction of tensile strength of LDPE greenhouse film under natural aging condition is taken as an exampleand the applicability of constructed model in the prediction of plastic aging behavior is researched.The results show that the relative error between prediction value and the actual value of tensile strength of LDPE greenhouse film after aging 18 and 21 months obtained from constructed model are 1.49% and 4.96% respectively.Prediction accuracy are higher than that(relative error are 3.40% and 6.75% respectively)obtained from GM(11)model obviously.Grey residual error GM(11)model based on Markvo needs less original data and has high prediction accuracythus it is a simple and reliable method for plastic aging behavior prediction. 相似文献
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Realistic estimation of grain nitrogen (N; N in grain yield) is crucial for assessing N management in crop rotations, but there is little information on the performance of commonly used crop models for simulating grain N. Therefore, the objectives of the study were to (1) test if continuous simulation (multi-year) performs better than single year simulation, (2) assess if calibration improves model performance at different calibration levels, and (3) investigate if a multi-model ensemble can substantially reduce uncertainty in reproducing grain N. For this purpose, 12 models were applied simulating different treatments (catch crops, CO2 concentrations, irrigation, N application, residues and tillage) in four multi-year rotation experiments in Europe to assess modelling accuracy. Seven grain and seed crops in four rotation systems in Europe were included in the study, namely winter wheat, winter barley, spring barley, spring oat, winter rye, pea and winter oilseed rape. Our results indicate that the higher level of calibration significantly increased the quality of the simulation for grain N. In addition, models performed better in predicting grain N of winter wheat, winter barley and spring barley compared to spring oat, winter rye, pea and winter oilseed rape. For each crop, the use of the ensemble mean significantly reduced the mean absolute percentage error (MAPE) between simulations and observations to less than 15%, thus a multi–model ensemble can more precisely predict grain N than a random single model. Models correctly simulated the effects of enhanced N input on grain N of winter wheat and winter barley, whereas effects of tillage and irrigation were less well estimated. However, the use of continuous simulation did not improve the simulations as compared to single year simulation based on the multi-year performance, which suggests needs for further model improvements of crop rotation effects. 相似文献
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This article mainly introduced the combination of gray linear regression model of the gray optimization and prediction, and applies it to the monitoring measurement of tunnel and underground engineering. Combined with engineering example, compare the grey optimization of the GM (2, 1) model, Verhust model and the metabolism model with the gray linear regression model, the metabolism model of gray linear regression model has more general applicability and accurate simulation prediction precision when predict rock deformation. 相似文献
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对青岛市2009～2040年的人口老龄化过程预测 总被引：1，自引：1，他引：0
一个国家或地区的人口老龄化过程进行准确预测是制定相应的宏观政策的重要依据。灰色预测将随机过程看成是在一定范围内变化的、与时间有关的灰色过程,根据GM (1,1)模型的建模机理,建立了青岛市老年人口数量与老年人口所占比重的灰色预测模型;利用模型预测得出2009～2040年青岛市老年人口数量与老年人口所占比重,并得到2035年老年人口数量将比2009年翻一番;分析了青岛市人口老龄化的成因,主要原因是青岛市20世纪50年代至60年代的两次生育高峰的影响,其次是由于在20世纪70年代采取计划生育政策使生育率下降,导致青少年人口比重降低;提出了逐步延长工作年限、提高退休年龄来解决劳动力不足的问题,建立健全城乡养老社会保障体系等应对人口老龄化的对策。 相似文献
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It is necessary to predict electromagnetic compatibility (EMC) for electronic equipment and systems. We proposed a fast EMC prediction approach via artificial neural networks (ANN). By choosing relevant electromagnetic interference parameters as the input prediction features, a back propagation (BP) neural network was used to construct the mapping between the input prediction features and the electromagnetic disturbance response of the sensitive system. The EMC fast prediction BP model was trained and tested by sample sets generated using an electromagnetic computational method. We used this method to predict the crosstalk coupling between two wires. The experimental results show the effectiveness of the proposed method. 相似文献
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为了解河北省棉花产量变化的规律,明确今后育种工作的目标和前景,利用灰色系统理论的GM (1,1)模型,依据1980~2003年河北省审定的棉花品种的区域试验产量,建立预测模型为: ^X(1)(k+1) ＝38965.718385e 0.024221－37990.718385。并在生产因素保持相对稳定的条件下,据此模型对河北省棉花生产进行规划性预测,为生产的规划与决策提供科学信息。明确棉花育种的总体目标是优化品种和品质结构,保持适纺中支纱品种选育的优势,重视发展目前市场短缺的长绒和中短绒陆地棉新品种选育。 相似文献
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梨木虱(Cacopsylla chinensis Yang et Li)在云南省的潜在分布区预测 总被引：1，自引：1，他引：0
为了掌握梨木虱在云南的潜在分布区,为梨木虱在云南省的发生、早期预警和防控提供参考资料,利用梨木虱的分布点数据和环境因子数据,通过MaxEnt生态位模型预测了梨木虱在云南省的适生范围区。结果表明：梨木虱在云南省适生范围分为4级,高适生区以黑色表示;中适生区以深灰色表示;低适生区以浅灰色表示;非适生区以白色表示。利用ROC曲线分析法对预测结果进行验证表明：其训练数据和测试数据分别为0.995和0.997,远大于随机分布模型的AUC值0.5,说明预测结果可靠。 相似文献
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选用合适的模型提高预测的精度和可靠性,为区域水环境管理提供科学依据,是水质预测要解决的关键问题。为了解决这一问题,根据辽河流域的实际,运用自回归滑动平均(ARMA)模型对辽河流域东陵大桥监测断面CODMn的水质变化趋势进行预测。结果表明：综合自相关函数、偏相关函数以及BIC原则,ARMA(1,1)模型能够更好地用于东陵大桥断面水质预测。拟合结果显示,相对误差在2.60%~25.98%之间,平均相对误差为13.69%,说明该模型能够充分利用近期水质资料信息,以精确预测未来水质变化趋势。而对东陵大桥监测断面CODMn的预测显示,未来CODMn呈现出增长态势,辽宁水环境管理任务仍然很重。最后,就ARMA模型应用于水质预测的问题和发展方向进行了探讨。 相似文献
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近红外光谱法测定大米中的淀粉含量 总被引：3，自引：0，他引：3
用化学方法测定64个大米样品中的淀粉含量,利用近红外谷物分析仪采集样品的近红外光谱,选择合适的光谱区间和光谱预处理方法。50个定标集样品的近红外光谱经二阶导数及标准多元离散校正(Standard MSC)预处理,结合偏最小二乘法(PLS)建立了大米中的淀粉含量测定的定标模型,其相关系数为0.8780。14个验证集样品用于外部检验,大米中的淀粉含量的模型预测值与化学值之间的相关系数为0.9498。 相似文献
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The two methods of estimating parameter in computable general equilibrium(CGE) model are introduced and compared:the calibration procedure and econometric estimation. The conclusions are:the estimation of parameter in CGE model must use the calibration procedure coupled with the econometric estimation method;the elasticity of output with respect to labor input,the marginal expenditure share for households and price elasticity of export demand are estimated by econometric estimation method;and other parameters of the CGE model can be get by calibration procedure. 相似文献