The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and th...The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and the 9th scale approximation signals. The pressure signals were studied by multi-scale and R/S analysis method. Hurst analysis method was applied to analyze multi-fractal characteristics of different scale signals. The results show that the characteristics of mono-fractal under scale 1 and scale 2, and bi-fractal under scale 3?9 are effective in deducing the hydrodynamics in slurry bubbling flow system. The measured pressure signals are decomposed to micro-scale signals, meso-scale signals and macro-scale signals. Micro-scale and macro-scale signals are of mono-fractal characteristics, and meso-scale signals are of bi-fractal characteristics. By analyzing energy distribution of different scale signals,it is shown that pressure fluctuations mainly reflects meso-scale interaction between the particles and the bubble.展开更多
针对在短期负荷功率预测过程中,因负荷功率波动大而导致单一模型存在预测精度低的问题,提出基于时间特征分析的短期负荷功率NST-IRN组合预测模型。首先,深度挖掘负荷功率的时间特性变化,将其分解为趋势成分以及循环分量,构建新型时间序...针对在短期负荷功率预测过程中,因负荷功率波动大而导致单一模型存在预测精度低的问题,提出基于时间特征分析的短期负荷功率NST-IRN组合预测模型。首先,深度挖掘负荷功率的时间特性变化,将其分解为趋势成分以及循环分量,构建新型时间序列(NTS)模型。其次,考虑多时间尺度输入特征与日类型对负荷功率的影响,构建含特征输入结构与深度学习结构的改进残差神经网络(IRN)模型。最后,利用D-S证据理论对NTS与IRN模型的预测结果进行权重融合,以获取最终负荷预测结果。以ISO New England的真实负荷数据进行仿真实验,结果表明所提模型具有较高的预测精度和鲁棒性。展开更多
How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is ...How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.展开更多
The problems of stability and stabilization for the discrete Takagi-Sugeno（T-S） fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function（PLKF） in each maximal over...The problems of stability and stabilization for the discrete Takagi-Sugeno（T-S） fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function（PLKF） in each maximal overlapped-rules group（MORG）,a new sufficient stability condition for the open-loop discrete T-S fuzzy time-delay system is proposed and proved.Then the systematic design of the fuzzy controller is investigated via the parallel distributed compensation control scheme,and a new stabilization condition for the closed-loop discrete T-S fuzzy time-delay system is proposed.The above two sufficient conditions only require finding common matrices in each MORG.Compared with the common Lyapunov-Krasovskii function（CLKF） approach and the fuzzy Lyapunov-Krasovskii function（FLKF） approach,these proposed sufficient conditions can not only overcome the defect of finding common matrices in the whole feasible region but also largely reduce the number of linear matrix inequalities to be solved.Finally,simulation examples show that the proposed PLKF approach is effective.展开更多
运用 R/S 方法，对1951～1997年兰州城市气候的温度、水汽压、相对湿度和日照百分率等指标的冬(1月)、夏(7月)及年平均值进行了分析计算，各项指标的Hurst指数 H 均大于0.5，说明它们存在明显的Hurst现象，反映出兰州市过去47年来气候...运用 R/S 方法，对1951～1997年兰州城市气候的温度、水汽压、相对湿度和日照百分率等指标的冬(1月)、夏(7月)及年平均值进行了分析计算，各项指标的Hurst指数 H 均大于0.5，说明它们存在明显的Hurst现象，反映出兰州市过去47年来气候变化存在趋势性成分即持续性的城市化增暖.至于各项指标的Hurst指数在冬、夏及年平均值间有差异，分析证明这是兰州城市化气候效应强度季节不同所造成.展开更多
基金Project(NCET-05-0413)support by the Program for New Century Excellent Talents in UniversityProject(YB0142112) support by Priming Foundation of East China University of Science and Technology
文摘The Daubechies second order wavelet was applied to decompose pressure fluctuation signals with the gas flux varying from 0.18 to 0.90 m3/h and the solid mass fraction from 0 to 20% and scales 1?9 detail signals and the 9th scale approximation signals. The pressure signals were studied by multi-scale and R/S analysis method. Hurst analysis method was applied to analyze multi-fractal characteristics of different scale signals. The results show that the characteristics of mono-fractal under scale 1 and scale 2, and bi-fractal under scale 3?9 are effective in deducing the hydrodynamics in slurry bubbling flow system. The measured pressure signals are decomposed to micro-scale signals, meso-scale signals and macro-scale signals. Micro-scale and macro-scale signals are of mono-fractal characteristics, and meso-scale signals are of bi-fractal characteristics. By analyzing energy distribution of different scale signals,it is shown that pressure fluctuations mainly reflects meso-scale interaction between the particles and the bubble.
文摘针对在短期负荷功率预测过程中,因负荷功率波动大而导致单一模型存在预测精度低的问题,提出基于时间特征分析的短期负荷功率NST-IRN组合预测模型。首先,深度挖掘负荷功率的时间特性变化,将其分解为趋势成分以及循环分量,构建新型时间序列(NTS)模型。其次,考虑多时间尺度输入特征与日类型对负荷功率的影响,构建含特征输入结构与深度学习结构的改进残差神经网络(IRN)模型。最后,利用D-S证据理论对NTS与IRN模型的预测结果进行权重融合,以获取最终负荷预测结果。以ISO New England的真实负荷数据进行仿真实验,结果表明所提模型具有较高的预测精度和鲁棒性。
基金supported by the National Natural Science Foundation of China(51075060)
文摘How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.
基金supported in part by the Scientific Research Project of Heilongjiang Province Education Bureau(12541200)
文摘The problems of stability and stabilization for the discrete Takagi-Sugeno（T-S） fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function（PLKF） in each maximal overlapped-rules group（MORG）,a new sufficient stability condition for the open-loop discrete T-S fuzzy time-delay system is proposed and proved.Then the systematic design of the fuzzy controller is investigated via the parallel distributed compensation control scheme,and a new stabilization condition for the closed-loop discrete T-S fuzzy time-delay system is proposed.The above two sufficient conditions only require finding common matrices in each MORG.Compared with the common Lyapunov-Krasovskii function（CLKF） approach and the fuzzy Lyapunov-Krasovskii function（FLKF） approach,these proposed sufficient conditions can not only overcome the defect of finding common matrices in the whole feasible region but also largely reduce the number of linear matrix inequalities to be solved.Finally,simulation examples show that the proposed PLKF approach is effective.
文摘运用 R/S 方法，对1951～1997年兰州城市气候的温度、水汽压、相对湿度和日照百分率等指标的冬(1月)、夏(7月)及年平均值进行了分析计算，各项指标的Hurst指数 H 均大于0.5，说明它们存在明显的Hurst现象，反映出兰州市过去47年来气候变化存在趋势性成分即持续性的城市化增暖.至于各项指标的Hurst指数在冬、夏及年平均值间有差异，分析证明这是兰州城市化气候效应强度季节不同所造成.
