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❤️ 内容介绍
鲁棒极限学习机(Robust Extreme Learning Machine, RELM)是一种基于极限学习机(Extreme Learning Machine, ELM)的算法,用于实现数据分类任务。RELM通过引入鲁棒损失函数,提高了ELM在面对噪声和异常值时的鲁棒性能。
RELM的实现步骤如下:
- 数据预处理:对原始数据进行预处理,包括数据清洗、特征选择和特征缩放等操作。
- 构建输入矩阵:将预处理后的数据按照矩阵的形式表示,其中每一行代表一个样本的特征,每一列代表一个特征。
- 随机初始化输入权重:随机生成输入层到隐藏层的权重矩阵,其中隐藏层的节点数可以根据经验或者交叉验证进行选择。
- 计算隐藏层输出:使用ReLU(Rectified Linear Unit)激活函数计算隐藏层的输出,即将输入矩阵与输入权重矩阵相乘,并将结果进行非线性变换。
- 求解输出权重:使用最小二乘法或者正则化方法求解输出权重矩阵,将隐藏层输出与样本的标签进行拟合。
- 预测分类结果:使用求解得到的输出权重矩阵,将测试样本的特征与隐藏层输出进行相乘,并通过激活函数得到预测的分类结果。
- 模型评估:使用评估指标(如准确率、精确率、召回率等)对模型进行评估,可以使用交叉验证等方法进行评估结果的稳定性。
通过以上步骤,可以使用RELM实现数据的分类任务。相比于传统的ELM算法,RELM在面对噪声和异常值时具有更好的鲁棒性能,可以提高分类模型的准确性和稳定性。
🔥核心代码
function [TrainingTime, TestingTime, TrainingAccuracy, TestingAccuracy] = elm(TrainingData_File, TestingData_File, Elm_Type, NumberofHiddenNeurons, ActivationFunction)% Usage: elm(TrainingData_File, TestingData_File, Elm_Type, NumberofHiddenNeurons, ActivationFunction)% OR: [TrainingTime, TestingTime, TrainingAccuracy, TestingAccuracy] = elm(TrainingData_File, TestingData_File, Elm_Type, NumberofHiddenNeurons, ActivationFunction)%% Input:% TrainingData_File - Filename of training data set% TestingData_File - Filename of testing data set% Elm_Type - 0 for regression; 1 for (both binary and multi-classes) classification% NumberofHiddenNeurons - Number of hidden neurons assigned to the ELM% ActivationFunction - Type of activation function:% 'sig' for Sigmoidal function% 'sin' for Sine function% 'hardlim' for Hardlim function% 'tribas' for Triangular basis function% 'radbas' for Radial basis function (for additive type of SLFNs instead of RBF type of SLFNs)%% Output: % TrainingTime - Time (seconds) spent on training ELM% TestingTime - Time (seconds) spent on predicting ALL testing data% TrainingAccuracy - Training accuracy: % RMSE for regression or correct classification rate for classification% TestingAccuracy - Testing accuracy: % RMSE for regression or correct classification rate for classification%% MULTI-CLASSE CLASSIFICATION: NUMBER OF OUTPUT NEURONS WILL BE AUTOMATICALLY SET EQUAL TO NUMBER OF CLASSES% FOR EXAMPLE, if there are 7 classes in all, there will have 7 output% neurons; neuron 5 has the highest output means input belongs to 5-th class%% Sample1 regression: [TrainingTime, TestingTime, TrainingAccuracy, TestingAccuracy] = elm('sinc_train', 'sinc_test', 0, 20, 'sig')% Sample2 classification: elm('diabetes_train', 'diabetes_test', 1, 20, 'sig')% %%%% Authors: MR QIN-YU ZHU AND DR GUANG-BIN HUANG %%%% NANYANG TECHNOLOGICAL UNIVERSITY, SINGAPORE %%%% EMAIL: EGBHUANG@NTU.EDU.SG; GBHUANG@IEEE.ORG %%%% WEBSITE: http://www.ntu.edu.sg/eee/icis/cv/egbhuang.htm %%%% DATE: APRIL 2004%%%%%%%%%%% Macro definitionREGRESSION=0;CLASSIFIER=1;%%%%%%%%%%% Load training datasettrain_data=load(TrainingData_File);T=train_data(:,1)';P=train_data(:,2:size(train_data,2))';clear train_data; % Release raw training data array%%%%%%%%%%% Load testing datasettest_data=load(TestingData_File);TV.T=test_data(:,1)';TV.P=test_data(:,2:size(test_data,2))';clear test_data; % Release raw testing data arrayNumberofTrainingData=size(P,2);NumberofTestingData=size(TV.P,2);NumberofInputNeurons=size(P,1);if Elm_Type~=REGRESSION %%%%%%%%%%%% Preprocessing the data of classification sorted_target=sort(cat(2,T,TV.T),2); label=zeros(1,1); % Find and save in 'label' class label from training and testing data sets label(1,1)=sorted_target(1,1); j=1; for i = 2:(NumberofTrainingData+NumberofTestingData) if sorted_target(1,i) ~= label(1,j) j=j+1; label(1,j) = sorted_target(1,i); end end number_class=j; NumberofOutputNeurons=number_class; %%%%%%%%%% Processing the targets of training temp_T=zeros(NumberofOutputNeurons, NumberofTrainingData); for i = 1:NumberofTrainingData for j = 1:number_class if label(1,j) == T(1,i) break; end end temp_T(j,i)=1; end T=temp_T*2-1; %%%%%%%%%% Processing the targets of testing temp_TV_T=zeros(NumberofOutputNeurons, NumberofTestingData); for i = 1:NumberofTestingData for j = 1:number_class if label(1,j) == TV.T(1,i) break; end end temp_TV_T(j,i)=1; end TV.T=temp_TV_T*2-1;end % end if of Elm_Type%%%%%%%%%%% Calculate weights & biasesstart_time_train=cputime;%%%%%%%%%%% Random generate input weights InputWeight (w_i) and biases BiasofHiddenNeurons (b_i) of hidden neuronsInputWeight=rand(NumberofHiddenNeurons,NumberofInputNeurons)*2-1;BiasofHiddenNeurons=rand(NumberofHiddenNeurons,1);tempH=InputWeight*P;clear P; % Release input of training data ind=ones(1,NumberofTrainingData);BiasMatrix=BiasofHiddenNeurons(:,ind); % Extend the bias matrix BiasofHiddenNeurons to match the demention of HtempH=tempH+BiasMatrix;%%%%%%%%%%% Calculate hidden neuron output matrix Hswitch lower(ActivationFunction) case {'sig','sigmoid'} %%%%%%%% Sigmoid H = 1 ./ (1 + exp(-tempH)); case {'sin','sine'} %%%%%%%% Sine H = sin(tempH); case {'hardlim'} %%%%%%%% Hard Limit H = double(hardlim(tempH)); case {'tribas'} %%%%%%%% Triangular basis function H = tribas(tempH); case {'radbas'} %%%%%%%% Radial basis function H = radbas(tempH); %%%%%%%% More activation functions can be added here endclear tempH; % Release the temparary array for calculation of hidden neuron output matrix H%%%%%%%%%%% Calculate output weights OutputWeight (beta_i)OutputWeight=pinv(H') * T'; % implementation without regularization factor //refer to 2006 Neurocomputing paper%OutputWeight=inv(eye(size(H,1))/C+H * H') * H * T'; % faster method 1 //refer to 2012 IEEE TSMC-B paper%implementation; one can set regularizaiton factor C properly in classification applications %OutputWeight=(eye(size(H,1))/C+H * H') \ H * T'; % faster method 2 //refer to 2012 IEEE TSMC-B paper%implementation; one can set regularizaiton factor C properly in classification applications%If you use faster methods or kernel method, PLEASE CITE in your paper properly: %Guang-Bin Huang, Hongming Zhou, Xiaojian Ding, and Rui Zhang, "Extreme Learning Machine for Regression and Multi-Class Classification," submitted to IEEE Transactions on Pattern Analysis and Machine Intelligence, October 2010. end_time_train=cputime;TrainingTime=end_time_train-start_time_train % Calculate CPU time (seconds) spent for training ELM%%%%%%%%%%% Calculate the training accuracyY=(H' * OutputWeight)'; % Y: the actual output of the training dataif Elm_Type == REGRESSION TrainingAccuracy=sqrt(mse(T - Y)) % Calculate training accuracy (RMSE) for regression caseendclear H;%%%%%%%%%%% Calculate the output of testing inputstart_time_test=cputime;tempH_test=InputWeight*TV.P;clear TV.P; % Release input of testing data ind=ones(1,NumberofTestingData);BiasMatrix=BiasofHiddenNeurons(:,ind); % Extend the bias matrix BiasofHiddenNeurons to match the demention of HtempH_test=tempH_test + BiasMatrix;switch lower(ActivationFunction) case {'sig','sigmoid'} %%%%%%%% Sigmoid H_test = 1 ./ (1 + exp(-tempH_test)); case {'sin','sine'} %%%%%%%% Sine H_test = sin(tempH_test); case {'hardlim'} %%%%%%%% Hard Limit H_test = hardlim(tempH_test); case {'tribas'} %%%%%%%% Triangular basis function H_test = tribas(tempH_test); case {'radbas'} %%%%%%%% Radial basis function H_test = radbas(tempH_test); %%%%%%%% More activation functions can be added here endTY=(H_test' * OutputWeight)'; % TY: the actual output of the testing dataend_time_test=cputime;TestingTime=end_time_test-start_time_test % Calculate CPU time (seconds) spent by ELM predicting the whole testing dataif Elm_Type == REGRESSION TestingAccuracy=sqrt(mse(TV.T - TY)) % Calculate testing accuracy (RMSE) for regression caseendif Elm_Type == CLASSIFIER%%%%%%%%%% Calculate training & testing classification accuracy MissClassificationRate_Training=0; MissClassificationRate_Testing=0; for i = 1 : size(T, 2) [x, label_index_expected]=max(T(:,i)); [x, label_index_actual]=max(Y(:,i)); if label_index_actual~=label_index_expected MissClassificationRate_Training=MissClassificationRate_Training+1; end end TrainingAccuracy=1-MissClassificationRate_Training/size(T,2) for i = 1 : size(TV.T, 2) [x, label_index_expected]=max(TV.T(:,i)); [x, label_index_actual]=max(TY(:,i)); if label_index_actual~=label_index_expected MissClassificationRate_Testing=MissClassificationRate_Testing+1; end end TestingAccuracy=1-MissClassificationRate_Testing/size(TV.T,2) end
❤️ 运行结果
⛄ 参考文献
[1] 焦广利,张璐,钟麦英.基于鲁棒极限学习机的污泥膨胀智能检测方法[J].山东科技大学学报:自然科学版, 2022(003):041.
[2] 王亚.基于极限学习机改进模型的煤矿突水水源识别研究[D].安徽理工大学[2023-09-02].DOI:CNKI:CDMD:1.1018.195306.
[3] 王石磊,陆慧娟,关伟,等.一种粒子群RELM的基因表达数据分类方法[J].中国计量学院学报, 2015, 26(2):6.DOI:10.3969/j.issn.1004-1540.2015.02.018.