排序方式: 共有15条查询结果,搜索用时 31 毫秒
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研究了GM(1,1)模型的建模方法,建立了太阳电池阵输出功率的GM(1,1)预测模型,针对电池出输出功率具有随季节波动的变化趋势,提出了采用实时在线的方法,建立动态新息GM(1,1)预测模型,经实例预测验证,动态新息GM(1,1)模型可明显地提高预测精度,且能对电池阵输出功率的波动趋势正确预测。 相似文献
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动态测量系统的抗扰性预报算法 总被引:8,自引:0,他引:8
为了克服采样数据可能包含的野值对状态预报的不利影响,本文在动态测量系统的有界影响滤波技术的基础上提出了状态预报的两组抗扰性算法,并进行了仿真计算。 相似文献
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刘亚英 《中国空间科学技术》1997,17(4):35-40
分析研究了空间碎片数随太阳辐射流量F10.7的变化;给出预报F10.7长期变化的计算方法和预测空间碎片数的数学模型。结果显示:①强太阳活动造成空间碎片年增长率下降;②空间碎片数与太阳活动11年变化密切相关,相关数为0.9;③空间碎片增长率约为发射率的两倍;④若发射率保持不变,则到2020年,大于10cm的碎片数将达到14500;⑤若小碎片的增长为大碎片增长的两倍,则到2020年,大于1cm的碎片数可达125000。 相似文献
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G.Y.Smolkov 《空间科学学报》2005,25(5):345-350
Presented are the ideas and proposals in regards to the pooling of by RAS, SB, ISTP, and CSSAR,CAS toward coordinated usage of existing ground-based and orbiting helio-geophysical observatories, single large installations as well as creating, forecasting services and new observing facilities, in the interests of achieving a profitable activity of the China-Russia Joint Research Center on Space Weather (JRCSW). 相似文献
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Gordon Reikard 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Space weather forecasts are currently used in areas ranging from navigation and communication to electric power system operations. The relevant forecast horizons can range from as little as 24 h to several days. This paper analyzes the predictability of two major space weather measures using new time series methods, many of them derived from econometrics. The data sets are the Ap geomagnetic index and the solar radio flux at 10.7 cm. The methods tested include nonlinear regressions, neural networks, frequency domain algorithms, GARCH models (which utilize the residual variance), state transition models, and models that combine elements of several techniques. While combined models are complex, they can be programmed using modern statistical software. The data frequency is daily, and forecasting experiments are run over horizons ranging from 1 to 7 days. Two major conclusions stand out. First, the frequency domain method forecasts the Ap index more accurately than any time domain model, including both regressions and neural networks. This finding is very robust, and holds for all forecast horizons. Combining the frequency domain method with other techniques yields a further small improvement in accuracy. Second, the neural network forecasts the solar flux more accurately than any other method, although at short horizons (2 days or less) the regression and net yield similar results. The neural net does best when it includes measures of the long-term component in the data. 相似文献
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Gordon Reikard 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Space weather series incorporate several distinct components, cycles at multiple frequencies, irregular trends, and nonlinear variability. The cycles are stochastic, i.e., the amplitude varies over time. Similarly, the trend is stochastic: the slope and direction of trending change repeatedly. This study sets out a combined model using both frequency and time domain methods, in two stages. In the first stage, a frequency domain algorithm is estimated and forecasted. In the second stage, the forecast is used as an input in a neural network. The combined model also includes a term enabling the model to react inversely to large deviations between the actual values and forecast. The models are evaluated using two data sets, the hemispheric power data obtained from the Polar Orbiting Environment satellites, and the Aa geomagnetic index. All the series are at a daily resolution. Forecasting experiments are run over horizons of 1–7 days. The models are estimated using a moving window or adaptive approach. The combined model consistently achieves the most accurate results. Among single equation methods, the frequency domain model is more accurate for the geomagnetic index because it is able to capture the underlying cycles more effectively. In the hemispheric power series, the cycles are less pronounced, so that time domain methods are more accurate, except at very short horizons. Nevertheless, in both data sets, the combined model works well because the frequency domain algorithm captures cyclical behavior, while the neural net is better able to capture short-term dependence and trending. 相似文献
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