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611.
This paper compares artificial neural network (ANN), fuzzy logic (FL) and linear transfer function (LTF)‐based approaches for daily rainfall‐runoff modelling. This study also investigates the potential of Takagi‐Sugeno (TS) fuzzy model and the impact of antecedent soil moisture conditions in the performance of the daily rainfall‐runoff models. Eleven different input vectors under four classes, i.e. (i) rainfall, (ii) rainfall and antecedent moisture content, (iii) rainfall and runoff and (iv) rainfall, runoff and antecedent moisture content are considered for examining the effects of input data vector on rainfall‐runoff modelling. Using the rainfall‐runoff data of the upper Narmada basin, Central India, a suitable modelling technique with appropriate model input structure is suggested on the basis of various model performance indices. The results show that the fuzzy modelling approach is uniformly outperforming the LTF and also always superior to the ANN‐based models. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
612.
【目的】探求真空微波干燥凡纳滨对虾的最佳工艺条件,以期为开发凡纳滨对虾即食食品提供技术参考。【方法】以新鲜凡纳滨对虾为原料,模糊数学感官评分为主要考察指标,在单因素试验基础上,选择载装量A、功率B、真空度C为自变量,利用响应面法和模糊数学评价法对真空微波干燥工艺进行优化。【结果】以感官评定为基础对真空微波干燥凡纳滨对虾的品质进行权重分析,得到权重集K=(色泽0.335,滋味0.305,香气0.215,组织质地0.145)。建立二次多项回归方程:Y=84.588+1.084A+1.409B+1.700C-7.353A2-8.793B2-13.860C2,显示载装量A、功率B、真空度C对感官评分有极显著影响(P<0.01)。通过响应面分析,得到真空微波干燥凡纳滨对虾的最佳工艺条件:载装量75 g,加热功率400 W,真空度0.08 MPa。在此条件下,真空微波干燥凡纳滨对虾品质良好,感官评分为(85.6±0.07)分,与预测值85.92分误差较小。【结论】响应面法优化凡纳滨对虾真空微波干燥工艺具有操作简单、优化条件精确、结果显示直观等优点;建立的回归方程能反映装载量等三个因素对指标的影响规律,并可进行实际预测。 相似文献
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基于双线偏振多普勒雷达识别地物回波 总被引:1,自引:0,他引:1
地物回波的存在严重影响雷达数据质量,从而影响定量降水估测精度。双线偏振多普勒天气雷达在识别地物回波方面具有明显优势。分析了北京市气象局C波段双线偏振多普勒天气雷达探测到的降水回波和地物回波的特征,在刘黎平的模糊逻辑算法基础上选择容易区分降水回波和地物回波的特征量,加入偏振参数构成偏振模糊逻辑算法。利用2012年的"7.21特大暴雨"个例对识别效果进行分析,并与常规模糊逻辑算法识别效果对比。结果表明,加入偏振参数的模糊逻辑算法能有效识别地物回波,对地物回波识别效果有明显改善,并有效解决了过度识别零速度降水区的问题。 相似文献
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A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,"test pattern" caused by test signal or radar hardware failures in CINRAD (China New Generation Weather Radar) SA and SB radar operational observations are investigated.In order to distinguish the test pattern from other types of radar echoes,such as precipitation,clear air and other non-meteorological echoes,five feature parameters including the effective reflectivity data percentage (Rz),velocity RF (range folding) data percentage (RRF),missing velocity data percentage (RM),averaged along-azimuth reflectivity fluctuation (RNr,z) and averaged along-beam reflectivity fluctuation (RNa,z) are proposed.Based on the fuzzy logic method,a test pattern identification algorithm is developed,and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm.Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed.The statistical results show that the test pattern identification algorithm performs well,since the test pattern is recognized in most cases.Besides,the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events. 相似文献
617.
A fuzzy inference system (FIS) and a hybrid adaptive network-based fuzzy inference system (ANFIS), which combines a fuzzy inference system and a neural network, are used to predict and model longshore sediment transport (LST). The measurement data (field and experimental data) obtained from Kamphuis [1] and Smith et al. [2] were used to develop the model. The FIS and ANFIS models employ five inputs (breaking wave height, breaking wave angle, slope at the breaking point, peak wave period and median grain size) and one output (longshore sediment transport rate). The criteria used to measure the performances of the models include the bias, the root mean square error, the scatter index and the coefficients of determination and correlation. The results indicate that the ANFIS model is superior to the FIS model for predicting LST rates. To verify the ANFIS model, the model was applied to the Karaburun coastal region, which is located along the southwestern coast of the Black Sea. The LST rates obtained from the ANFIS model were compared with the field measurements, the CERC [3] formula, the Kamphuis [1] formula and the numerical model (LITPACK). The percentages of error between the measured rates and the calculated LST rates based on the ANFIS method, the CERC formula (Ksig = 0.39), the calibrated CERC formula (Ksig = 0.08), the Kamphuis [1] formula and the numerical model (LITPACK) are 6.5%, 413.9%, 6.9%, 15.3% and 18.1%, respectively. The comparison of the results suggests that the ANFIS model is superior to the FIS model for predicting LST rates and performs significantly better than the tested empirical formulas and the numerical model. 相似文献
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针对一类输入受限的非匹配不确定非线性系统,提出了一种抗饱和自适应反步控制方法.利用模糊干扰观测器在线逼近系统的未知非匹配不确定及干扰,采用反步控制方法设计自适应控制器.控制系统设计中引入限幅滤波器,有效降低了控制输入饱和对系统稳定性的影响,并且控制器设计无需对虚拟控制律进行重复求导.利用李亚普诺夫稳定性定理,证明了闭环系统渐近稳定.仿真结果表明了该方法的有效性. 相似文献