Questions tagged [ensemble-modeling]

In machine learning, ensemble methods combine multiple algorithms to make a prediction. Bagging, boosting, and stacking, are some examples.

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33 views

How can compare suggestion models with different performances?

I have 4 class binary classification models. That models identify which class a particular students is suitable for. For example, we have user 1 and 4 classes ...
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27 views

Making an ensemble model for high F1 score

I presently have 2 algorithms that have a numerical output. Using a threshold of 0.9, I get the classification output. Let's say they are: P (high precision, low recall) R (high recall, low precision)...
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29 views

How to assign a weight for classifiers when using weighted majority voting?

I am trying to apply weighted majority voting on an ensemble as a combiner method. I read different papers and articles, however, I am still a bit lost on: How the weighted majority voting works How ...
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199 views

Probability that ensemble model is correct based on accuracies of its classifiers

I'm trying to understand what I did wrong when trying to answer this question. The exact question is: Assume that we have 3 trained prediction models, and each model outputs either -1 or 1. We then ...
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40 views

Understanding Weighted learning in Ensemble Classifiers

I'm currently studying Boosting techniques in Machine Learning and I happened to understand that in Algorithms like Adaboost, each of the training samples is given a weight depending on whether it was ...
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How to make an lstm ensemble with different input shapes using keras

This is what I got so far for making an lstm ensemble with one model input for each of the lstm models and for the ensemble model and it works perfectly. ...
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Large general-purpose model vs ensemble of many smaller models

I am reading this paper - https://arxiv.org/abs/1503.02531v1 - devoted to knowledge distillation in neural networks. One interesting approach is mentioned in this paper in sections ...
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1answer
26 views

Base model in ensemble learning

I've been doing some research on ensemble learning and read that for base models, model with high variance are often recommended (can't remember which book I read this from exactly). But, it seems ...
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39 views

How does stacking help Bias and Variance?

How does stacking help in terms of bias and variance? I have a hunch that stacking can help reduce bias but i am not sure, could someone refer to a paper?
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Different types of Ensemble learning methods [closed]

I've been reading and searching information about different types of Ensemble learning methods however I am a bit confused and want to make sure my understanding is correct. Below is graph of how I ...
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61 views

precision recall curve is like stairs [closed]

I am training an ensemble model using a 400 data set sample this led to a precision recall curve that looks like stairs ? what would be the reason beside the low number of samples ?
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Hybrid Ensembling

I read a paper recently where researchers were trying to do classification using ensembling methods. I first read about the concept of BOOSTED-STACKING there.For those who dont know , I can give a ...
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How to interpret gradient descent in boosting ensembles?

I struggle to grasp the role of gradient based optimization in boosting ensembles. As far as I understand boosting means combining a bunch of estimators (of the same types, usually decision trees) ...
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1answer
16 views

How many run should we implement on the machine learning model?

Theoretically, we can implement fix seed on the machine learning model to get the same results every run (reproducible)but it may leads to bias. So, in order to prevent bias, I gonna run the model ...
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How do I proceed with model selection?

Only data scientist in an organization and I could really use a sounding board here. In Phase One of a project I deployed four models and served their average as the prediction. I used Random Forest ...
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1answer
121 views

How to tune an weighted voting ensemble method?

I am working on kidney cancer patients' data with 5 unbalanced labels. These codes are contained of Normalization, Oversampling on Feature Engineering part. A list of 9 ordinary Machine Learning ...
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3answers
120 views

Ensembling expressions

I have two models, $m_1$ and $m_2$, and I want to ensemble them into a final model. I want to be able weight one or the other more according to a grid search. There are two main ideas that come to my ...
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What if the votes for 2 classes are equal in an ensemble learning technique?

Suppose in ensemble learning technique, if the number of models that predict class 1 is equal to the number of models that predict class 0. Then, which class will be decided as output?
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192 views

How to train with cross validation? and which f1 score to choose?

I got similar results in 2 models which consists of similar algorithms. Model 1 with cv=10 has a f1'micro' of 0.941. See code below. Model 2 only train test split (no cv) has f1'micro' 0.953. Now here ...
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DecisionTreeRegressor under the hood of GradientBoostingClassifier

I'm inspecting the weak estimators of my GradientBoostingClassifier model. This model was fit on a binary class dataset. I noticed that all the weak estimators under this ensemble classifier are ...
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KL Divergence between Predictions and Ground truth

I've got four (non-linear, tree-based) models in production and using the average of them as the served prediction. We get ground truth data immediately. During training the optimized candidate models ...
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41 views

How to improve model performace when model shows a systemic pattern in residues

I'm working on a regression model using Boosting algorithms (CatBoost, XGBoost, and LightGBM). All models give similar accuracy of 0.2 RMSE (Target varies from 0 to 1). I obtained the following plots ...
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142 views

In XGBoost, how is a leaf index corresponding to the particular leaf node in actual base learner trees?

I've trained a XGBoost model for regression, where the max depth is 2. ...
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1answer
248 views

Are “Gradient Boosting Machines (GBM)” and GBDT exactly the same thing?

In the category of Gradient Boosting, I find some terms confusing. I'm aware that XGBoost includes some optimization in comparison to conventional Gradient Boosting. But are Gradient Boosting ...
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A question about SAMME algorithm (Adaboost)

According to this article (which references the original paper), this is the SAMME algorithm for multiclass classification using Adaboost: I would like to understand what is this term in step ...
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83 views

Stacking - Appropriate base and meta models

When implementing stacking for model building and prediction (For example using sklearn's StackingRegressor function) what is the appropriate choice of models for the base models and final meta model?...
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1answer
30 views

How Adaboost calculates error for each weak learner in training?

I am studying the Adaboost classification algorithm because i would like to implement it from scratch. I understand how it works, but i am not able to understand where some steps are placed. I will ...
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1answer
75 views

How to compare Random Forest with other models

I am new to Machine Learning and I am trying to undrestand the Out of Bag Error in Random Forests and its use. Let's say that we have a dataset. First we use the whole dataset (without splitting it) ...
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18 views

Selecting models for ensemble from large group of models with high uncertaintly

I'm in a situation where many models have been created, and I have their cross-validation performances as well as performance on test data. I need to select models for inclusion in a simple bagging ...
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15 views

General practices for building an incremental learning model which never forgets?

I'm new to datascience and appreciate your sage advice! I need to build an incremental learning model, and I know there's a lot that goes into something like that, but I'd like to highlight the most ...
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1answer
27 views

Model with 2 datasets: combine time series data and statistics

I am new to data science modelling so apologies if using wrong terminology in advance. I have a standard time series dataset of historical prices which is used to train/test a simple Random Forest ...
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58 views

What is the best way to use Early Stopping in an ensemble (stacking) model?

I have a training and a test dataset. I would like to use the output of Model A in an ensemble model. However, I would like to use early stopping. Usually, I would create Model A for each K-fold (on ...
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1answer
35 views

Augmenting the validation set in Ensemble Model

I have 8 models which I have trained on 90% of my set (training set) and tracked its performance on the loss of the validation set (10% of the original set). I want to generate an ensemble model by ...
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2answers
426 views

Is there any way to plot ROC curve for Ensemble hard voting classifier?

I am working on a multi-class text classification problem and performing an Ensemble learning for text classification. I chose hard voting as ensemble technique. I tried to plot ROC curve for my ...
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20 views

Decision Boundary with random new observations vs observations from test set

I'm trying to plot decision boundary for Decision Tree classifier. Classifier is trained on training set, and decision boundary (contour) using random new observations and observations from test set ...
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47 views

Classification model accuracy with ensemble methods

I came through this statement in a Machine Learning text book based on law of large numbers: Suppose you build an ensemble containing 1,000 classifiers that are individually correct only 51% of the ...
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76 views

Stacked Model performance?

I am currently working with a dataset that seems very easily separable and I have an accuracy of 99% for SVM (NN-98%, RF-98%, DT-96-97% and I have checked for leakage & overfitting). As part of my ...
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210 views

Stacking and Ensembling methods in Data Science

I understand that using stacking and ensembling has become popular, and these methods can give better results than using a single algorithm. My question is: What are the reasons, statistical or ...
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1answer
784 views

XGBoost Log Loss different from GridSearchCV Log Loss

I have a classification problem where I am trying to predict if the data returns a 1 or 0. So your classic binary classification. I have my set of data that I have split into the dependent variables (...
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1answer
53 views

How does bagging help reduce the variance

I learned that bagging helps reduce variance by averaging but I couldn't understand this. Can someone explain this intuitively?
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914 views

How do I Combine two CNN models (h5 format)?

I have two CNN models, both of them are trained on the same dataset. How do I combine/ensemble both to make predictions on test data? ...
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861 views

What is the difference between ensemble methods and hybrid methods, or is there none?

I have the feeling that these terms often are used as synonyms for one another, however they have the same goal, namely increasing prediction accuracy by combining different algorithms. My question ...
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1answer
21 views

Model stacking with instance attributes [duplicate]

From what I have understood about model stacking: the meta estimator trains to combine the N-models predictions to fit the ground truth. Once trained, it combines the 1st level output to approach the ...
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1answer
24 views

What is the form of data used for prediction with generalized stacking ensemble?

I am very confused as to how training data is split and on what data level 0 predictions are made when using generalized stacking. This question is similar to mine, but the answer is not sufficiently ...
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1answer
17 views

Low leves of probability observed after modelling.Is it right to scale the probability

I have done modelling on imbalanced class , without any sampling methods. Event rate is around 0.1 ,After modelling I am getting probalities more at the lower side close to zero.I have tried differnt ...
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1answer
75 views

Can I use SVC() as a base_estimtor for ensemble methods?

I am currently testing out a few different ensemble methods on my dataset. I've heard that you can also use support vector machines as base learners in boosting and bagging methods but I am not sure ...
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67 views

Can bagging ensemble consist of heterogeneous base models?

Bagging or bootstrap aggregation seems to make sense for time series forecasting using an ensemble because bagging randomizes subsets of the data with replacement. However, I've only seen bagging used ...
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27 views

Creating a sub-model from pre-trained model

I have a pre-trained model having the following architecture: ...
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10 views

Domain specific language to describe ensemble model

I'm looking for some tool/library/widely used approach to describe Hierarchical Model structure like ensemble: It's absolutely straightforward how to do it with simple ensemble like It can be ...