共查询到20条相似文献，搜索用时 265 毫秒
1.
遗传算法优化人工神经网络模型在日光温室湿度预报中的应用 总被引：4，自引：3，他引：1
提出一种基于遗传算法优化BP神经网络的方法预测日光温室湿度环境因子。实测日光温室内影响空气湿度的环境因子组成数据样本作为神经网络的输入,采用基于实数编码的遗传算法替代随机设定神经网络的初始权阈值,然后通过改进的BP算法在由遗传算法确定的搜索空间中对网络进行精确训练。模型预报值和实测值基于1：1线的决定系数R2和预测平均相对误差MSE分别为0.9857和3．1％。结果表明,遗传算法优化BP神经网络预报模型收敛速度快、预测精度高。可为日光温室的湿度环境调控制提供理论依据和决策支持。 相似文献
2.
在饲料配方中,数学方法占有非常重要的地位。综述了饲料配方设计中应用的几种数学方法:试差法、线形规划、目标规划、模糊规划、灰线形规划和随机规划等方法,从而为建立科学、合理的饲料配方优化系统奠定良好的基础。 相似文献
3.
实现持续低碳化发展是冷链物流技术创新与优化的重要方向。基于成本约束视角,将冷链物流存储、配运、交付诸环节的运营成本和碳排放成本纳入企业总成本目标函数,构建冷链物流配送路径优化模型,使用蚁群算法与遗传算法变异算子结合求解,提高了算法迭代收敛速度。以医药冷链物流配送为例进行算法仿真优化与分析,验证了降低物流成本与节能减排可协同优化,获得良好的经济效益。模型和算法对环境可持续视角下的冷链物流配送路径问题有理论和实践意义。 相似文献
4.
马铃薯贮藏库温度受室外温度、室内马铃薯呼吸释放温度、通风降温等因素的影响难以准确预测,提出了一种改进遗传算法(Genetic Algorithm,GA)优化支持向量回归机(Support Vector Regression,SVR)的马铃薯贮藏库温度预测方法。该方法针对支持向量回归机参数难以选择、容易陷入局部极小的缺点,引入了具有并行性、全局搜索能力强的GA算法,结合局部搜索能力强的模拟退火算法(Simulated Annealing,SA),实现支持向量回归机的自动寻优。以新疆某农产品加工公司马铃薯贮藏库实测温度数据为样本,建立SAGA-SVR马铃薯贮藏库温度预测模型,进行贮藏库温度准确的预测。仿真结果表明,与GA-SVR、反向传播(Back Propagation,BP)温度预测模型的预测结果相比较,SAGASVR预测结果优于GA-SVR、BP预测结果,具有良好的预测效果。该预测方法较好地解决了系统非线性、小样本等问题,为类似应用场合地温度预测提供参考。 相似文献
5.
6.
陈思 《农产品加工．学刊》2018,(15)
通过综述克氏原螯虾的营养需求与主体饲料配方的研究进展,主要阐述饲料蛋白质水平和能蛋比对克氏原螯虾生长的影响,旨在为主体饲料配方的研发和改进提供参考。 相似文献
7.
扩繁条件对3种丛枝菌根真菌(AMF)的影响 总被引：1，自引：0，他引：1
为了提高AM真菌的培养效率,降低培养成本,采用温室盆栽法,以玉米和红三叶草为宿主,以摩西球囊霉(Glomus intraradices,G.i)、根内球囊霉(Glomus mosseae,G.m)地表球囊霉(Glomus versiforme,G.v) 3种AM真菌为供试菌种,在以河砂、草炭、珍珠岩、蛭石和泥炭不同配比组成的3种基质中进行培养,并设置2个营养液浓度梯度（无营养液;10%浓度霍氏营养液）,进行3×2因子交叉实验,通过测定侵染率、孢子密度以及宿主的光合特性,从而筛选出各菌种最优的轻型基质配方及其相应的营养液浓度。结果表明,P2（蛭石:草炭:河砂=4:1:1）配方是G.m和G.i良好的扩繁基质,P3（珍珠岩:蛭石:草炭:河砂=2:2:1:1）配方是最适合G.v的扩繁基质,在对菌种的侵染率、产孢量以及宿主植物的光合效率的提高等方面优于其他配方。与以往研究结果不同的是,本研究中的3个基质配方,施加营养液的处理都明显降低了3种AM真菌的孢子数,降幅分别为43.51%~96.26%、57.50%~99.39%、27.79%~92.56%;且每个菌种的侵染率也不同程度地降低,其机理有待于进一步研究。 相似文献
8.
种子是农业科技的载体,是特殊的农业生产资料,种子的品质在不断提高,种子市场竞争日益激烈,种子生产厂家及经营单位如何应对这种局势?我们首先应面对我们的种子最终用户--农户,了解、生产、供给他们所渴盼的种子,赢得农户才能赢得市场. 1调查方法与内容本次调查涉及全省14个地市的40个县,以村为样点,以农户为基本抽样单位,采用抽样调查的方法,在110个样点上抽样,调查时选用分层抽样的方式将所调查地区样点的农户依照经济水平分上中下三层,中层居多的适当多占比例,本次每个样点抽样单位的数目为该样点户数的10%,调查后结果汇总,总户数为1798户.调查作物种类有玉米、大豆、花生、水稻、棉花、小麦等.调查内容包括购种渠道,购种时首先考虑的问题如价格、质量、购种方式及购种时间等. 相似文献
9.
10.
康奈尔净碳水化合物和净蛋白质体系(CNCPS)是国际上公认的最权威的反刍动物营养模型。为了验证CNCPS预测奶水牛生产性能的准确性和提高生产性能的可能性,本试验选择产奶量、年龄、胎次和体况均相近地中海奶水牛45头,平均体重为600kg,泌乳期为产犊后60天左右。随机将试验牛分成3组:对照组采用牧场原有的TMR日粮配方,优化组1和2分别是在原有配方的基础上利用CNCPS生成优化配方1和优化配方2。按照CNCPS6.5分析奶水牛饲料原料营养组分,并研究利用其优化奶水牛泌乳高峰期日粮的效果。结果表明应用CNCPS体系评价饲料营养组分有助于对奶水牛日粮配方的优化,奶水牛实际产奶量和代谢蛋白或代谢能允许产奶量无显著差异,优化组产奶量高于对照组。CNCPS体系可以用来预测奶水牛产奶量,并能够优化日粮,提高产奶量。 相似文献
11.
ZHANG Chun-tao~ 《保鲜与加工》2004,(7):78-81
Crossover operator and mutation operator are basic operators of genetic algorithm , which play important roles in improving the quality of the solution populations. We propose the improved crossover operator , mutation operator and rotation operator on the basis of good point set with the traveling salesman problem , the experimental result shows these operators are very efficient. 相似文献
12.
Distribution Network Structure planning is a complex combinatorial optimization problem,which is difficult to solve properly by using traditional optimization methods.In order to solve this problem,Improved Immune Genetic Algorithm is introduced to the distribution network optimal planning. Improved Immune Genetic Algorithm draws into the immune diversity and antibody's density mechanism to maintain the individual's diversity and remains evolution algorithm's global stochastic searching ability,so it can promote diversity and the whole optimal-searching ability of genetic algorithm.The optimal module takes the minimum annual cost as its object,and the capacity and voltage drop of feeder and the radiation of distribution network as its restrictions.According to the require of radiation of distribution network,the spanning tree of the alternative network is taken as the initial solution to speed up the calculation.And the branch-exchange method is used in designing crossover operator and mutation operator to avoid the radiation checking and enhance the optimizing ability.This algorithm has been illustrated effectively by examples,at the same time,the calculation example demonstrates that,the algorithm has higher calculation speed than the traditional immune genetic algorithm. 相似文献
13.
The method of damage identification in soil-wall system was studied; a new approach based on improved multi-population genetic algorithm (IMGA) was developed. First, the simplified dynamic-detection model of soil-wall system was established, meanwhile, the theoretical analysis of characteristic equations in soil-wall system was conducted when soil in damage status. The objective function based on characteristic equations was established. Then, the improvements of multi-population genetic algorithm, including the adoption of real-valued representation, adaptive cross operator and adaptive mutation operator, were conducted. Finally, the localization and quantification of the soil-wall system damage were performed by IMGA with and without the consideration of noise, respectively. The results indicate that damage location and damage extent can be detected efficiently, and anti-noise performance is better. 相似文献
14.
曲线和曲面拟合的改进缩张算法 总被引：1，自引：0，他引：1
本文对缩张算法进行了多处改进,其中最主要的是与基于数值微分的改良高斯-牛顿法相结合,形成了曲线与曲面拟合的改进缩张算法。新算法不需提供非线性方程的偏导数,但可利用近似偏导数指导搜索方向,提高搜索效率。改进缩张算法减少了复杂非线性方程拟合的运算负荷,提高了利用度点反馈调节搜索步长和区域的敏感度,增强了跳出局部最优陷阱的能力。新算法可在较大初值范围内实现全局最优拟合。本文以3个不同类型的实例验证了新算法的拟合功效。编制了可动态显示拟合过程的Matlab程序,可供曲线和曲面拟合应用者使用。 相似文献
15.
In this paper, a simple genetic algorithm (GA) is presented for optimizing the structural systems with discrete design variable. First, the origin, basic process of GA was discussed. In order to improve the convergence of GA, considering the difficulty in choosing the probability of crossover and mutation, an adaptive GA, in which the probability of crossover and mutation were varied depending on the fitness values of the solutions, was introduced. Finally, the availability of the adaptive GA was shown by an example. 相似文献
16.
For the prediction of coal and gas outburst intensity, Incorporate Genetic Algorithm Based Back Propagation Neural Network(IGABP) is proposed to solve the limitations in the traditional GABP such as time consuming, optimal stop condition of GA pretreatment indeterminacy, independency and complex task of great importance etc. IGABP addresses some improvements in adaptive crossover and mutation probability to promote GA performance. And with the introduction of BP operator in the evolution of GA operations, the standard GA optimization is from random search to self guiding search and the convergence rate of GA is upgraded, as well as the determination ability of exact solution. With a simulation as a case study, it is found that the minimum error and standard error with IGABP are 0.012 and 0.227, respectively, compared with -0.126 and 1.529 by traditional GABP. 相似文献
17.
基于量子多种群遗传算法的蛋白质二级结构预测 总被引：1，自引：1，他引：0
为进一步提高蛋白质二级结构的预测精度,将量子计算和多种群算法融入到传统的遗传神经网络算法中。同时考虑到氨基酸残基的众多理化性质是形成蛋白质二级结构的主要驱动力,构象偏好也是影响蛋白质二级结构形成的重要因素,提出了一种新的基于理化性质和构象信息编码的量子多种群遗传算法。该方法蕴含了丰富的生物信息,可以有效减少网络系统的不确定性。用PDBselect25中的24条蛋白质进行测试,结果表明该算法可以有效的预测蛋白质的二级结构,平均预测精度达到72.10%,分别比SNN、DSC、PREDSATOR方法提高了7.80%、3.70%和3.41%。该方法采用混合编码的形式进行编码,在每个种群内部引入量子计算,形成了以多种群遗传算法来带动量子计算,量子计算反作用于多种群算法的双重优化的方法,可有效提高蛋白质二级结构预测的精确度。 相似文献
18.
Job shop scheduling is an important part of manufacturing process. Pre-mature, local optimal solution or low convergence rate of Genetic Algorithm may come across in solving scheduling problem in multi-Job shop. To avoid those unhealthy tendencies, this paper introduced the Dynamical Niche Sets-based Cooperative Evolutionary Algorithm model.In the Algorithm, Process-based chromosome encoding method was used; the crossover operator and mutation operator were designed to adjust operation sequences and choose process routes. The cooperative scheduling problem in multi-Job shop was solved using dynamical niche sets technology and multi-population cooperative evolution method. The Experiment result shows the proposed method has good advantages. 相似文献
19.
By analyzing the inherent uncertainties, discrete uncertainties and external environmental uncertainties, a dual-feedback control strategy and the dynamic scheduling method are proposed to solve the dynamic scheduling problem of vehicle air-conditioning assembly shop under uncertainty. Considering the reentrant constraint, equipment capacity constraint, and time discrete constraint etc., the multi-objective scheduling model of vehicle air-conditioning assembly shop is set up,taken the earliness/tardiness, process time, production cost and quality loss as optimization objectives. According to the characteristic of the model, sectional chromosome encoding, crossover operator and mutation operator are designed to prevent the generation of illegal solutions and improve efficiency of the algorithm. An example is given to prove the feasibility and validity of the approach. 相似文献
20.
A novel genetic algorithm,simply written as REGA, is proposed with the idea to limit the number of repeating crossover and replacing the worst individuals of the current generation by the best ones of the former generation. The algorithm overcomes the premature phenomenon of the simple genetic algorithm. According to Markov's limitation theorem, we prove its global convergence,explore the properties of the genetic algorithm written as RSGA only based on repeating crossover,and provide a method to calculate the mathematic expectation on the absorption time for the two algorithms. Finally,the simulation shows that the algorithm REGA can solve the optimization problem containing more than one global optimal solutions,on one hand,while eliminating the drawback of local optimum and rapidly enhancing the average fitness. On the other hand, REGA is valuable for function optimization. 相似文献