【DELM预测】基于鲸鱼算法改进深度学习极限学习机实现数据预测附matlab代码

1 简介

人工神经网络的最大缺点是训练时间太长从而限制其实时应用范围,近年来,极限学习机(Extreme Learning Machine, ELM)的提出使得前馈神经网络的训练时间大大缩短,然而当原始数据混杂入大量噪声变量时,或者当输入数据维度非常高时,极限学习机算法的综合性能会受到很大的影响.深度学习算法的核心是特征映射,它能够摒除原始数据中的噪声,并且当向低维度空间进行映射时,能够很好的起到对数据降维的作用,因此我们思考利用深度学习的优势特性来弥补极限学习机的弱势特性从而改善极限学习机的性能.为了进一步提升DELM预测精度，本文采用鲸鱼算法进一步优化DELM超参数，仿真结果表明，改进算法的预测精度更高。

2 部分代码

%_________________________________________________________________________%% 鲸鱼优化算法             %%_________________________________________________________________________%% The Whale Optimization Algorithmfunction [Leader_score,Leader_pos,Convergence_curve]=WOA(SearchAgents_no,Max_iter,lb,ub,dim,fobj)​% initialize position vector and score for the leader Leader_pos=zeros(1,dim);Leader_score=inf; %change this to -inf for maximization problems​​%Initialize the positions of search agentsPositions=initialization(SearchAgents_no,dim,ub,lb);​Convergence_curve=zeros(1,Max_iter);​t=0;% Loop counter​% Main loopwhile t<Max_iter    for i=1:size(Positions,1)                % Return back the search agents that go beyond the boundaries of the search space        Flag4ub=Positions(i,:)>ub;        Flag4lb=Positions(i,:)<lb;        Positions(i,:)=(Positions(i,:).*(~(Flag4ub+Flag4lb)))+ub.*Flag4ub+lb.*Flag4lb;                % Calculate objective function for each search agent        fitness=fobj(Positions(i,:));                % Update the leader        if fitness<Leader_score % Change this to > for maximization problem            Leader_score=fitness; % Update alpha            Leader_pos=Positions(i,:);        end            end        a=2-t*((2)/Max_iter); % a decreases linearly fron 2 to 0 in Eq. (2.3)        % a2 linearly dicreases from -1 to -2 to calculate t in Eq. (3.12)    a2=-1+t*((-1)/Max_iter);        % Update the Position of search agents     for i=1:size(Positions,1)        r1=rand(); % r1 is a random number in [0,1]        r2=rand(); % r2 is a random number in [0,1]                A=2*a*r1-a;  % Eq. (2.3) in the paper        C=2*r2;      % Eq. (2.4) in the paper                        b=1;               %  parameters in Eq. (2.5)        l=(a2-1)*rand+1;   %  parameters in Eq. (2.5)                p = rand();        % p in Eq. (2.6)                for j=1:size(Positions,2)                        if p<0.5                   if abs(A)>=1                    rand_leader_index = floor(SearchAgents_no*rand()+1);                    X_rand = Positions(rand_leader_index, :);                    D_X_rand=abs(C*X_rand(j)-Positions(i,j)); % Eq. (2.7)                    Positions(i,j)=X_rand(j)-A*D_X_rand;      % Eq. (2.8)                                    elseif abs(A)<1                    D_Leader=abs(C*Leader_pos(j)-Positions(i,j)); % Eq. (2.1)                    Positions(i,j)=Leader_pos(j)-A*D_Leader;      % Eq. (2.2)                end                            elseif p>=0.5                              distance2Leader=abs(Leader_pos(j)-Positions(i,j));                % Eq. (2.5)                Positions(i,j)=distance2Leader*exp(b.*l).*cos(l.*2*pi)+Leader_pos(j);                            end                    end    end    t=t+1;    Convergence_curve(t)=Leader_score;end​​​​

3 仿真结果

4 参考文献

[1]吴忠强, 卢雪琴, 何怡林,等. 基于鲸鱼算法优化极限学习机的微电网故障诊断方法[J]. 智慧电力, 2022, 50(2):7.​

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