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Genetic Algorithm Based on New Evaluation Function and mutation model for Training of BPNN

Tsinghua Science and Technology 2002年第1期7卷 28-31页

作者：周祥何小荣陈丙珍 Department of Chemical Engineering Tsinghua University Beijing 100084 China

A local minimum is frequently encountered in the training of back propagation neural networks (BPNN), which sharply slows the training process. In this paper, an analysis of the formation of local minima is presented, and an improved genetic algorithm (GA) is introduced to overcome local minima. The Sigmoid function is generally used as the activation function of BPNN nodes. It is the flat characteristic of the Sigmoid function that results in the formation of local minima. In the improved GA, pertinent modifications are made to the evaluation function and the mutation model. The evaluation of the solution is associated with both the training error and gradient. The sensitivity of the error function to network parameters is used to form a self adapting mutation model. An example of industrial application shows the advantage of the improved GA to overcome local minima. 

关键词： back propagation neural networks (BPNN) local minimum genetic algorithm (GA) evaluation function mutation model

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Shale Fracturability Graphic Template Based onMixed Analytic Hierar-chy Process andmutation Theory

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Energy Engineering 2024年第7期121卷 1921-1943页

作者： Sichen Li Dehua Liu Liang Cheng Pan Ma College of Petroleum Engineering Yangtze UniversityWuhan430100China Hubei Drilling and Recovery Engineering for Oil and Gas Key Laboratory Wuhan430100China

Due to the depletion of conventional energy reserves,there has been a global shift towards non-conventional energy *** oil and gas have emerged as key *** resources have dense and heterogeneous reservoirs,which require hydraulic fracturing to *** process depends on identifying optimal fracturing layers,also known as‘sweet spots’.However,there is currently no uniform standard for locating these sweet *** paper presents a new model for evaluating fracturability that aims to address the current gap in the *** model utilizes a hierarchical analysis approach and a mutation model,and is distinct in its use of original logging data to generate a fracturability evaluation *** this paper’s shale fracturing sweet spot evaluation method based on a two-step mutation model,four wells in different blocks of Fuling and Nanchuan Districts in China were validated,and the results showed that the proportion of high-yielding wells on the sweet spot line could reach 97.6%,while the proportion of low-producing wells was only 78.67%.Meanwhile,the evaluation results of the model were compared with the microseismic data,and the matching results were consistent.

关键词： Shale reservoir hydraulic fracturing analytic hierarchy process mutation model microseismic

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The mutation analysis of ultrasonic acoustic emission in plant stem

The mutation analysis of ultrasonic acoustic emission in pla...

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2011年全国压电和声波理论及器件应用研讨会

作者： Jian-xin WANG~(1,*) Mei-li SUI~2 Shi-feng YANG~3 Xian-wei GAO~1 1 Department of Electronic and Information Engineering,Beijing Electronic Science and Technology Institute,Beijing 100070,China 2 Beijing Senior Expert Technology Center Chinese Academy of Sciences,Beijing 100046,China 3 College of Electronic Information and Automation,Tianjin University of Science And Technology,Tianjin 300222, China

＜正＞Produced by cohesion between water molecules or adhesion to the conduits wall,the plant cavitation is accompanied by the vessel walls vibration which is the indicator of the water *** ultrasonic acoustic emissi... 详细信息

关键词： ultrasonic acoustic emissions UAEs mutation model

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