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基于Tan-Sigmoid函数参数调整的BP神经网络改进算法 被引量:8
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作者 罗兵 黄万杰 杨帅 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2006年第1期150-153,158,共5页
为提高BP神经网络的性能,对网络的联接权值W和神经元的tan-sigmoid转换函数的参数T、θ进行调整,使信息分布存储于权值矩阵及转换函数中,比传统的算法具有更强的非线性映射能力.经严密的数学推导,给出了最终的改进算法公式和1个预测需... 为提高BP神经网络的性能,对网络的联接权值W和神经元的tan-sigmoid转换函数的参数T、θ进行调整,使信息分布存储于权值矩阵及转换函数中,比传统的算法具有更强的非线性映射能力.经严密的数学推导,给出了最终的改进算法公式和1个预测需求量的算例,结果表明,改进后的算法能有效地减少隐层节点数,且能加快收敛速度和提高收敛精度. 展开更多
关键词 BP神经网络 tan-sigmoid转换函数 分布存储
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基于Sigmoid函数光滑化的等效热容和有限元法求解相变传热问题 被引量:5
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作者 何宜谦 杨海天 《应用基础与工程科学学报》 EI CSCD 2011年第5期817-829,共13页
为避免等效热容法中因等效热容函数阶跃变化对计算精度的影响,提出了一个基于Sigmoid函数的光滑焓函数,通过焓对温度的导数,可得到光滑和连续的等效热容函数,并结合有限元法与有限差分法建立了求解相变传热问题的数值模型.通过数值算例... 为避免等效热容法中因等效热容函数阶跃变化对计算精度的影响,提出了一个基于Sigmoid函数的光滑焓函数,通过焓对温度的导数,可得到光滑和连续的等效热容函数,并结合有限元法与有限差分法建立了求解相变传热问题的数值模型.通过数值算例,对所提方法进行了验证,探讨了有限元网格密度、热容阵的数值积分格式以及Sigmoid函数相关参数对计算结果的影响,与解析解及以往的平均化方法相比,结果令人满意. 展开更多
关键词 传热 相变 等效热容法 sigmoid函数 有限元方法
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基于FPGA的电子鼻中Sigmoid函数分区间线性逼近实现 被引量:3
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作者 张航 陈向东 《计算机应用》 CSCD 北大核心 2014年第A02期352-353,356,共3页
对表驱动线性逼近方法实现的sigmoid函数进行分析,在Matlab中对其仿真,得到误差曲线。该误差曲线在不同区间内误差相差较大,由此提出分区间线性逼近法实现sigmoid函数。不同区间采用不同的插值间隔,以尽量减少ROM资源的使用。经Matlab仿... 对表驱动线性逼近方法实现的sigmoid函数进行分析,在Matlab中对其仿真,得到误差曲线。该误差曲线在不同区间内误差相差较大,由此提出分区间线性逼近法实现sigmoid函数。不同区间采用不同的插值间隔,以尽量减少ROM资源的使用。经Matlab仿真,得到改进后的误差曲线,其最大误差未增大。最后在Quartus II中建立工程,调用Modlesim进行RTL仿真,证明该方法可行。 展开更多
关键词 sigmoid函数 线性逼近 分区间 RTL级仿真
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A Neural Based Experimental Fire-Outbreak Detection System for Urban Centres
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作者 Agaji Iorshase Shangbum F. Caleb 《Journal of Software Engineering and Applications》 2016年第3期71-79,共9页
Incessant fire-outbreak in urban settlements has remained intractable especially in developing countries like Nigeria. This is often characterized by grave socio-economic aftermath effects. Urban fire outbreak in Nige... Incessant fire-outbreak in urban settlements has remained intractable especially in developing countries like Nigeria. This is often characterized by grave socio-economic aftermath effects. Urban fire outbreak in Nigerian cities has been on increase in recent times. The major problem faced by fire fighters in Nigerian urban centres is that there are no mechanisms to detect fire outbreaks early enough to save lives and properties. They often rely on calls made by neighbours or occupants when an outbreak occurs and this accounts for the delay in fighting fire outbreaks. This work uses Artificial Neural Networks (ANN) with backpropagation method to detect the occurrence of urban fires. The method uses smoke density, room temperature and cooking gas concentration as inputs. The work was implemented using Java programming language and results showed that it detected the occurrence of urban fires with reasonable accuracy. The work is recommended for use to minimize the effect of urban fire outbreak. 展开更多
关键词 Fire-Outbreak Detection Neural Network Urban Fires Backpropagation sigmoid transfer function Fire Alert Temperature Smoke Density Cooking Gas Concentration WEIGHTS
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A Review of an Expert System Design for Crude Oil Distillation Column Using the Neural Networks Model and Process Optimization and Control Using Genetic Algorithm Framework 被引量:1
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作者 Lekan Taofeek Popoola Gutti Babagana Alfred Akpoveta Susu 《Advances in Chemical Engineering and Science》 2013年第2期164-170,共7页
This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (... This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (FL) and genetic algorithm (GA) framework were chosen as the best methodologies for design, optimization and control of crude oil distillation column. It was discovered that many past researchers used rigorous simulations which led to convergence problems that were time consuming. The use of dynamic mathematical models was also challenging as these models were also time dependent. The proposed methodologies use back-propagation algorithm to replace the convergence problem using error minimal method. 展开更多
关键词 Artificial Neural Network CRUDE Oil Distillation Column Genetic ALGORITHM FRAMEWORK sigmoidal transfer function BACK-PROPAGATION ALGORITHM
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