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An Improved Learning Algorithm for BP Model and its Application to Load Forecasting in Power Systems
This paper analyses the cause of very slow learning rate during the time of ap-proaching the minim um poi nt in con vertional BP algorithm, by introducing weight factor into themodification of the connection weight,an improved leavning algorithm for BP model is presented,itcan sign ificantly in crease the learning rate and improve con vergent behaviour.As an illustrative ap-plication example,the n umeriCal resu It of the medium-term load forecasting is given. 相似文献
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The study on Dynamic Route Guidance System (DRGS) is an important research in the field of Intelligent Transportation System(ITS),which guide the behaviors of travelers by providing them with optimal route based on real-time traffic information. As a result the travel time can be saved and the traffic congestion can be avoided. The route guidance algorithm can compute the best route between the begin point and destination. The globe near best property and real-time property must be considered , the Genetic Algorithm have qualifications for globe optimal and parallel algorithm. Genetic algorithm(GA),for solving the shortest route,is proposed in this thesis?The ordered real code rule,crossover,mutation are given. The efficiency of the GA is proved through an example. 相似文献
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A new and better mathematical model is presented, which is based on the in-depth analysis of the material recombined system and the sufficient expenses produced during the material recombined. In order to solve the problem, the authors choose the genetic algorithm, put forward a improved coding method, and get satisfactory answer through experiments. Advantages of efficiency and economic value are given. 相似文献
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SHI Qing-xi~ 《保鲜与加工》2006,(4):111-114
The Causality Diagram theory,which adopted graphical expression of knowledge and direct causality intensity of causality,overcomes some shortages in Belief Network and has evolved into a mixed causality diagram methodology coped with discrete and continuous variable.But it is difficult that the structure of Causality Diagram given by expert.Because the complexity of causality diagram structure goes up exponentially through the number of the vertex's increasing,it is NP-hard problem to find the most possible structure from a set of data.The authors discuss approaches and present Genetic Algorithm,to find the most possible structure from a set of data.Experiment shows the method is effective. 相似文献
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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
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The aims at optimization of structure with damper braces is studied in this paper. The sum of damping coefficient of all damper braces is considered as a goal function, and the storey displacements are considered as constraint conditions. The program,which introduces the non-proportional damp matrix, based on genetic algorithm and time history is used to analyze the optimization of a damper braced frame. The results are reasonable and show that the genetic algorithm is an efficient method to optimize the damper braced structure. 相似文献
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The authors introduce a sort of novel adaptive penalty gene, transform the constrained problem into unconstrained problems. An solution is given for this unconstrained problem with genetic algorithm, and then it is used as initial values for the constrained variable metric method to get precise solution. The numerical experiments illustrate that this hybrid genetic algorithm is more efficient than the genetic algorithm, and at most situations globally optimal solution can be gotten. 相似文献
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Distribution Network Structure planning is a complex combinatorial optimization problem, which is difficult to solve properly by using traditional optimization methods. The authors put forward Multiple Population Immune Genetic Algorithm (MPIGA)for optimal planning of distribution network structure, and do optimal search to different aspects of optimization goals. During the genetic evolution process, biologic immune mechanism is introduced to do some immune operator operation on chromosomes of each population, which can interact mutually by the shift of excellent units. By this way, it can effectively prevent population retrogression, promote diversity and the whole optimal searching ability of genetic algorithm. In order to minimize network annual expenditure, a mathematic model is established. The optimal solution is obtained by this algorithm, which has been illustrated effectively by specific examples at the same time. 相似文献
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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
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This paper discusses the method of synthesizing planar multilink mechanisms based on GA. The pivotal technology is coding, creating population, account fitness, genetic operation and defining population size. This method does not require initial mechanisms and can search for plural appropriate mechanisms simultaneously. It is efficient about the non-linear problem. As an example, configuration of 4-bar planar mechanisms is decided in a practical application. It can be used the synthesis of 6-bar or more bar planar mechanisms as well. 相似文献
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Desulfuration process is a very sophisticate reaction which is not only diverse but also non-line. A RBF algorithm based on generalized genetic optimization is proposed after studying the standard genetic and RBF algorithm. The authors also introduce its application in prediction Model for molten Iron Desulfuration. The algorithm perfectly resolve the problem of random selection of RBF cluster center number. Furthermore, it also reduces the time which GA uses. Comparison between the simulation results of RBF and RBF algorithm Based on GGA optimization further proves the efficiency and precision of its application in Prediction Model for Molten Iron Desulfuration. Finally the result of the test shows that after adopting the algorithm, the end-point hitting ratio can reach eighty-five percent. This indicate the algorithm has the engineering practicability. 相似文献
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Furnace is the most important equipment in ceramics produce.In order to realize tactics of JIT,a optimal model of roller furnace is given out,and discuss the problem of solving E/T furnace shop scheduling by genetic algorithm.Contrast of genetic algorithm and EDD rule is carry out by computer simulation,the results indicate that the genetic algorithm is better and more practical. 相似文献
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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
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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
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In order to achieving the Automation of profile optimization and offering more reasonable schemes,the author proposes a kind of computer method based on hereditary algorithm,which is using mathematic methods to simplify the profile lines as a list of points and using cut-fill gross as aim's function and using restriced conditions to control the profile lines,the authors optimize the list of points of changing slopes,the results of the method are more accurate than the artificial design and can provide many kinds of schemes within short time.In the actual projects we can properly increase the condition restraints to design more high-quality lines.If GIS platform is added to it,the profile can be optimized more effectively and more intuitionisticly. 相似文献
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With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system. 相似文献
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改进遗传算法在饲料配方设计中的应用 总被引:1,自引:1,他引:0
针对现有饲料配方软件的局限性,以白绒山羊饲料配方为例,提出一种基于改进遗传算法的求解方法。与标准遗传算法相比,采用随机联赛选择替代轮盘赌模型,优化了选择策略;采用不同的随机数交叉和高斯变异,改进了交叉算子与变异算子。测试结果表明,该方法具有良好的运算效率,拓宽了搜索空间,提高了对重点区域的搜索能力,降低了成本,为复杂问题的优化提供了一种新的思路。 相似文献
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基于遗传算法结合偏最小二乘的潮土碱解氮高光谱特征及含量估测 总被引:2,自引:0,他引:2
提取土壤碱解氮特征光谱是利用高光谱数据进行其含量估测的关键。对山东省典型潮土土壤样本测试高光谱并进行变换;采用遗传算法(GA)结合偏最小二乘法(PLS),在筛选潮土碱解氮含量特征谱区的基础上,构建潮土碱解氮含量偏最小二乘(PLS)回归估测模型;优选最佳模型并与相关分析、逐步回归分析和单纯偏最小二乘回归分析的模型进行比较。结果表明:潮土碱解氮特征波段为449~469nm,988~1001nm,1065~1078nm,1716~1736nm,1912~1925nm,2213~2233nm,2262~2275nm;基于各输入光谱特征谱区构建的估测模型决定系数R 2均较高,其中基于反射率一阶导数光谱筛选的特征谱区,构建的模型精度最高,数据点(147个)为原始全谱的7.17%,建模R 2达到0.97,均方根误差RMSE为4.78mg/kg,验证R 2为0.95,RMSE为5.49mg/kg,对潮土碱解氮含量具有较好的预测准确性;在光谱变换形式中,反射率的一阶导数表现最佳;方法比较显示采用遗传算法结合偏最小二乘(GA-PLS)获得较高预测精度的同时,可简化模型。说明遗传算法结合偏最小二乘法(GA-PLS),可有效筛选土壤碱解氮的特征波段,减少模型参与变量,提高估测精度。 相似文献