Questions tagged [classification]

An instance of supervised learning that identifies the category or categories which a new instance of dataset belongs.

657 questions with no upvoted or accepted answers
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15
votes
4answers
850 views

XGBoost outputs tend towards the extremes

I am currently using XGBoost for risk prediction, it seems to be doing a good job in the binary classification department but the probability outputs are way off, i.e., changing the value of a feature ...
6
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2answers
68 views

Which classification algorithms are negatively affected by class imbalances?

I've seen a few posts and papers floating around the web (mostly those related to over/undersampling, SMOTE, and cost-sensitive training) that, when discussing class imbalance, specify that certain ...
5
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1answer
50 views

Data transformations in hierarchical classification

I am building a hierarchical text classifier using the Local Classifier Per Parent Node (LCPN) approach with the 'siblings' policy as described in the PDF: E.g. if we have the classes 1.1, 1.2, 2.1, ...
5
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3answers
105 views

How can we model the class which maximizes the event probability?

I’d like to ask about a case when we would like to predict the best class of some input variable, so that the probability of event will be maximized. For example the advertisement type for a given ...
5
votes
1answer
91 views

Decision trees, categorizacion and oversampling

I want to create a model to predict the propensity to buy a certain product. As my proportion of 1's is very low, I decided to apply oversampling (to get a 10% of 1's and a 90% of 0's). Now, I want to ...
4
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0answers
121 views

How to implement hierarchical labeling classification?

I am currently working on task of eCommerce product name classification, so I have categories and subcategories in product data. I noticed that using subcategories as labels delivers worse results (84%...
4
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2answers
2k views

How to use one hot encoding of string categorical features in keras?

I am dealing with a binary classification problem. The output column of my dataset is already encoded in 0/1. The problem is that I have many categorical features (columns), which are strings and I ...
4
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1answer
5k views

Using class weights in Keras with multiple binary outputs which are not simply one-hot-encoded

My labels are binary vectors of length 5, e.g., [0, 0, 1, 1, 1]. My label set is very biased, 1-to-50, where the case [0, 0, 0, 0, 0] is very common while all ...
4
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0answers
396 views

Hyperparameter tuning in multiclass classification problem: which scoring metric?

I'm working with an imbalanced multi-class dataset. I try to tune the parameters of a DecisionTreeClassifier, ...
4
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0answers
395 views

Illustrating the dimensionality reduction done by a classification or regression model

Tl;DR: You can predict something, but how do you explain the prediction? Your usual classification/regression setup Lets say the data is a classic regression/classification problem: several ...
3
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0answers
17 views

Serializing a trained classification model into a set of actionable insights

I'm looking for ways to convert a trained classification model into a list of insights based on the resulting parameters of the model. To make an example, let's assume we trained a decision tree to ...
3
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0answers
29 views

Stratified selection based on the y response creates a bias in information (Berkson's bias)?

I have a database which has individuals in different months and a target variable which indicates wheter an event happened or not, let's say: ...
3
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1answer
35 views

Facial recognition architecture

Image recognition uses deep learning, and in particular CNNs to train on and recognise faces. Usually, this entails training on lots of data. However, recently, we have seen face recognition being ...
3
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1answer
41 views

User actions sequence classification

I have a training set where each row is a series of user actions on a website (logged in, sent an invoice, etc.) and times deltas in ms between these actions. Each row has a label — a corresponding ...
3
votes
1answer
77 views

How to update the posterior belief when we are observing a stream of correlated data from a fixed but unknown data source

I want to build a [probabilistic] model that aims to infer the true value of an unknown categorical variable, $y \in \{1,2,..., K\}$. We have a dataset $(X,y): \mathbb{R}^d\rightarrow \{1,2,..., K\}$ ...
3
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0answers
32 views

Keras model with second to last sigmoid activated Conv1D layer followed by globalMaxPool outputs values outside [0,1]. Why?

I am trying to train a binary classifier. It is a residual network with skip layers etc. but ultimately, the bottom two layers are a 1D convolution with sigmoid activation followed by a global max ...
3
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0answers
388 views

Target mean encoding worse than ordinal encoding with GBDT ( XGBoost, CatBoost )

I have a dataset of 23k rows of an unbalanced dataset 85/15 ratio, 10 variables ( 9 of which are categorical ) , i'm using CatBoost and XGBoost for a binary classification. I applied cv (5 iteration ...
3
votes
1answer
188 views

TF-IDF vs TF for classification

Let's suppose that I have a dataset of 1000 documents. Each document is a restaurant review (so relatively short text) and it has labels {Negative, Indifferent, Positive}. Let's suppose that the ...
3
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0answers
284 views

Adjust class weights due to class imbalance and class importance Multi class classification XGBoost

With respect to this question and the answer given by @Esmailian, Would anyone be able to let me know if Class B has a higher importance or the positive class ( i.e. it needs to have a higher ...
3
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0answers
1k views

How to train continuous/soft classification model?

The classic classification problem is like finding the function $F:\mathbb{R}^n\mapsto \{0,1\}$. The label set will be [Apple,Banana,Banana,...,Apple]. What if I want to train a function $F:\mathbb{R}...
3
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0answers
211 views

Multivariate time Series classification - One class

I need your help with time series classification. I have measurements of different medical parameters for patients captured at every one hour. The output label is whether the patient has Acute Kidney ...
3
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0answers
120 views

Feature Importance Python

My dataset has around 1000 features and 30k rows. All the feautres have value either 1 or 0. My target variable is Size which 3 classes : Small, Medium and Large. I have around 5k "small" data ...
3
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1answer
136 views

Extract features from a survey

I need to use the answers from a questionnaire for training a classifier. I discovered that some questions can have nested sub-questions.. Let's say (just an example) that I want to predict whether a ...
3
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1answer
726 views

Are single input single output neural networks possible?

This might be a weird question but I'm trying to have a deep understanding of how neural networks work theoretically. I was doing some tests with my perceptron and I decided to test it on a single ...
3
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0answers
65 views

make prediction with a time serie

I want to build a model that can detect which driver is driving now the car based on a dataset that contains 20 driver records for 3600s each driver ( the dataset contains all the car sensors values ...
3
votes
3answers
196 views

How to create an ensemble that gives precedence to a specific classifier

Suppose that in a binary classification task, I have separate classifiers A, B, and C. If I ...
3
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1answer
445 views

Multi-task learning for Multi-label classification?

I have a multi-label classification problem wherein each example can belong to one of the pre-defined classes (or can belong to none of them). I was wondering if I can somehow apply multi-task ...
3
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1answer
52 views

Restrictions on my skewed validation data

I have a severely skewed data sets consisting of 20 something classes where the smallest class contains on the order of 1000 samples and the largest several millions. Regarding the validation data, ...
3
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3answers
77 views

Find recurrent dates in a small set (and get rid of non recurrent ones)

I need help in the analyse of a categorization problem. Given a set of dates (small set: 20 elements maximum), I would like to group dates which are equally distributed (with a tolerance). It can be,...
3
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0answers
5k views

Adding multilabel classifier to TensorFlow example

I am starting with the generic TensorFlow example. To classify my data I need to use multiple labels (ideally multiple softmax classifiers) on the final layer, ...
3
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0answers
110 views

FUZZY ARTMAP for continuous data

I was going through an IEEE Research paper which has used Fuzzy ARTMAP for predicting the price of electricity given some highly correlated data. As per my basic understanding about Fuzzy ARTMAP it ...
2
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1answer
45 views

Sentiment analysis of tweets (Train model on a labelled dataset and use on some other unlabelled data)

I have a huge amount of tweets on a particular topic say 'ABC' and the data is not labelled. I want to perform multi-class sentiment analysis of these tweets. I tried many unsupervised clustering ...
2
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3answers
63 views

ML: Classification Model Comparison

Given is a dataset that I need to use for a classification and I want to compare the performance of different classification models. Let's assume, I want to look at logistic regression (with ...
2
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1answer
16 views

How to use ontologies for text classification?

I am new to machine learning and want to classify sentences using ontologies (taxonomies/ knowledge graphs) and supervised learning methods (I have an annotated training dataset). My question is how ...
2
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0answers
28 views

The most informative curve for imbalance datasets

For the imbalanced datasets: Can we say the Precision-Recall curve is more informative, thus accurate, than ROC curve? Can we rely on F1-score to evaluate the skillfulness of the resulted model in ...
2
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0answers
30 views

How to implement SVM from scratch?

I am trying to build a SVM from scrath and I would like to maximize this Lagrarian expression: I know what variables means but I would like to know how this maximization is implemeted. Should I start ...
2
votes
1answer
44 views

Binary Classification Comparing two time series of variable length

Is there a machine learning model (something like LSTM or 1D-CNN) that takes two time series of variable length as input and ...
2
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0answers
39 views

Platt Scaling vs Isotonic Regression for reliability curve

I am learning classifier probability calibrations and have calibrated an eleastic net model using both Platt scaling and isotonic regression. As you can see in the attached image Platt scaling (on the ...
2
votes
1answer
42 views

What is the current best state of the art algorithm for graph embedding of directed weighted graphs for binary classification?

Sorry if this is a newbee question, I'm not an expert in data science, so this is the problem: We have a directed and weighted graph, which higher or lower weight values does not imply the ...
2
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1answer
34 views

I have 3 graphs of a binary Logistic Regression that I want to understand better what is happening and learn of a strategy to make the model better

My problem is the following: I have a binary Logistic Regression model with a very imbalanced dataset that outputs the percentage of the prediction. As can be seen in the images, as the threshold is ...
2
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0answers
50 views

Predict a label based on multiple rows each one case?

I need to do a classification of binary labels. The dataset represents a loan procedure. So one row is a certain moment of a process for a certain case. The dataset consists of several cases more ...
2
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0answers
17 views

GuassinaNB parital fit not working properly

I'm trying to make a partial fitting with GuassianNB here's small snippet of my code ...
2
votes
1answer
34 views

Classification algorithm with multiple output for a set of features

I want to build a classification algorithm that will predict multiple values for a set of features. For instance, lets say I have a customer demographic data like Income, age, sex, city and I want to ...
2
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0answers
40 views

How can I improve the accuracy of my model? (Cab Cancellation Prediction)

I am trying to predict based on several parameters like trip type, car type, source of booking, start time, lead time (start- book) and a few other params whether or not a customer will cancel. From ...
2
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0answers
20 views

Approach to classify blocks of time series

I am wondering if there exists an approach to classify blocks of time series, and not specifically individual time series. If so, can you point me out papers/articles/tutorials where these type of ...
2
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1answer
55 views

Machine learning model with simultaneous function optimization

Consider the following scenario. I am a sculpturer and customers ask me for what price I am willing to provide them with some statues. Their request for sculptures can vary in difficulty, quantity, ...
2
votes
1answer
40 views

How to choose layer from which to unfreeze image classification model

I'm wondering what steps do you take to decide on the part of the model to unfreeze. Do you do multiple experiments? Since the use of GPU is expensive, you must have some guidelines. Note: I know ...
2
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0answers
17 views

How to estimate the marginal distribution of a class with respect to one predictor in a classification task?

I have a dataset with a binary dependent variable $y \in \{0,1\}$ and a set of predictors $x1,x2,..,t$. Here, $t$ is the time in minutes (in 24 hrs, that is $t \in (0,1440)$). I want to estimate the ...
2
votes
1answer
30 views

Attitude to text mining and preparing tokens, irrelevant words, low accuracy

For purpose of quite big project I am doing a text mining on some documents. My steps are quite common: All to lower case Tokenization Stop list and stop words Lemmatizaton Stemming Some other ...
2
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1answer
39 views

Relating ROC curves with class statistics

I have three neural net models that I am running on the same dataset (of 7 classes) and calculate their class performance and also ROC curves. The firs tmodel is a 4-layer model with 8 neurons in each ...

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