All Questions
Tagged with classification multi-class
263 questions
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Recommended multiclass classification algortihms for this particular problem
I'm using this dataset, https://archive.ics.uci.edu/ml/datasets/Drug+consumption+%28quantified%29, in a research whose main goal is to find correlations among attributes that influences people to be ...
5
votes
1
answer
2k
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Summarising Precision/Recall Measures in Multi-class Problem
I have a hierarchical multi-class classification system, that classifies records into about 500 different categories. I want to summarise the performance of the classifier in a simple way.
A measure ...
- 843
1
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0
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145
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Learning separate models vs single model
I have seen in several texts that: "We learn separate models for each class/category". What does this mean and how is this different from learning a single model to classify all the classes?
- 153
2
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1
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56
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Searching for list of terms using Google in order to build a bag-of-words for a particular category [closed]
I am having a hard time understanding the process of building a bag-of-words. This will be a multiclass classification supervised machine learning problem wherein a webpage or a piece of text is ...
user162992
5
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3
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5k
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Cut-off probability for multi-class problem
I would like to know whether there is a cut-off probability of outcome when classifying observations into more than 2 classes.
For instance, the threshold in binary logistic regression is usually 0.5,...
- 101
6
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2
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10k
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SMOTE for multiclass classification
I have a dataset in which the target variable has three classes. The approx distribution is as follows:
"-1" - 4%
"0" - 90%
"1" - 6%
I did not find any package in R which can run smote for ...
- 257
1
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2
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2k
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Multi-class classification with growing number of classes - question
I have a multi-class classification problem where the algorithm should detect (and later on classify) new classes.
An example for such a task could be classifying if an image shows a dog or a cat. ...
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4
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2
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2k
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Expected error in a multiclass classification problem
I have a multiclass classification problem with more than 1,000 classes. I've trained several classifiers (SVM, kNN, Random forests, etc) for 10, 100, 500 and 1000 of the classes to estimate the ...
- 371
6
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3
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701
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Machine Learning a Bijective Function
Is there any research on learning a bijective function from data?
For example, let's imagine that we're trying to learn to assign four random musicians to instruments in a band. We have:
lead ...
- 63
1
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3
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4k
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binary and multiclass classifiers
I have a simple yes/no problem so I was naturally inclined towards using a binary classifier because I was reading the book, A Course in
Machine Learning by Hal Daumé III and I quote from it:
[ Binary ...
2
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0
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108
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Using SVM output as binary classifier input
For a certain document multi-class classification problem, I am experimenting with training an SVM in logistic regression mode (using liblinear). While the ...
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2
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1
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5k
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Calculate accuracy using true/false positives/negatives
I got
predicted = [0, 0, 1, 0, 1, 2, 1, 0, 1, 0]
actual = [1, 2, 1, 2, 0, 1, 0, 2, 1, 1]
from multiclass classifier
Next, I calculate for 3 classes
...
1
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1
answer
950
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Classification - train on full data, predict on partial data
I have a dataset X which consists of two parts: X1 and X2. X2 is believed to depend on X1. And there is a resulting dataset Y which depends on both X1 and X2. For every training sample X1 and X2 are ...
- 146
2
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2
answers
157
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Classification using independent models for each class
One way to explain my data is to use the example data below. Here, I use the iris dataset to depict the four independent scores for each instance. My task is to ...
- 1,182
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2
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8k
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Neural network for multi label classification with large number of classes outputs only zero
I am training a neural network for multilabel classification, with a large number of classes (1000). Which means more than one output can be active for every input. On an average, I have two classes ...
- 111
6
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3
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8k
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Multiclass classification having class imbalance with Gradient Boosting Classifier
I am using Abalon data for classification from UCI(https://archive.ics.uci.edu/ml/machine-learning-databases/abalone/abalone.data). I have scaled data and used TSNE for visualization.
...
- 161
2
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1
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2k
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Improve performance for weak class in multi-class classification
In a multi-class classification problem, models that I've trained (and which I intend to use in a majority voting ensemble) consistently get weak performance on a couple of specific classes. There is ...
- 121
2
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1
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2k
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LibSVM - Multi class classification with unbalanced data
I tried to play with libsvm and 3D descriptors in order to perform object recognition. So far I have 7 categories of objects and for each category I have its number of objects (and its pourcentage) :
...
- 121
5
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1
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How do I use negative examples (in addition to positive ones) for training a multiclass softmax classifier (or a neural net with softmax output)?
Suppose we are training a neural network for multi-class classification, and we use softmax (or hierarchical softmax) as its output layer.
For positive examples, we need to maximize the log ...
- 173
-1
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1
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311
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How can I use SVM or Logical Regression on polynomial class labels?
I was told that SVM would return good results for my research task, but afaik SVMs and Logical regression work with binomial class labels.
How can I make them work with classes that have more than ...
- 209
3
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2
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20k
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Logistic Regression for non-binary classification (multi-class) in R
I am trying to use glm(family = binomial(link = 'logit')) for a classification task with 14 classes. I know that logistic regression is used in R for binary ...
- 297
0
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0
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686
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How to evaluate the model performance under multiclass random forest fitting?
I just use the code to run random forest for multiclass response. I binarize the output to apply the ROC score for model performance. Could someone can advice other methods for the performance ...
- 463
4
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3
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17k
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Coefficients in Support Vector Machine
I have a few related questions:
What is the total number of fitted paramaeters in Python Support Vector Machine: sklearn.svm.SVC(kernel='linear') and sklearn.svm.SVC(kernel='rbf')?
I am trying to ...
- 442
1
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236
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Evaluate the performance of online (incremental) machine learning methods against batch learning methods
What are the criteria which can be used to evaluate the performance of online machine learning methods in comparison with the batch learning methods(classification)?
Prediction statistics like ...
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1
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1
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21
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Classification: one of the classes have a much wider range of predictor values then others.
How do I supposed to deal with the situation when one of the classes is very general, it actually covers a bunch of classes, but other 3 classes I have are very precise. I have a data that has a lot ...
2
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0
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216
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Streaming multi-class classification with growing number of classes
I'm looking for some references for online multi-class classification problem where the number of classes grows over time. Concretely, the data at time-step $t$ comes in the form $\left(\mathbf{x}_t, ...
- 121
1
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0
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192
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Why would LDA not perform well on a 2 class classification problem?
I am performing emotion detection on speech samples. I extract say features (energy, pitch, etc) from the speech files and then try to classify the files by performing LDA and using Matlab's ...
- 111
0
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0
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590
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AdaBoost, how to understand the "weighted class probability estimates" in SAMME.R
SAMME.R is a multi-class classifier of AdaBoost. And I am confused about the weighted class probability estimates in SAMME.R. Here is the algorithm:
(1) Initialalize the observation weights $w_i=\...
- 1,391
2
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0
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281
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Multi Class Classification of Text
I am trying to develop a model that classifies text documents to ~50 classes. Would appreciate any help regarding what should my approach be to make it happen?
I have a training set of ~5000 ...
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24
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Classification method with (potentially) endless training input
What is the best multi class classification method with (potentially) endless training input?
The classificator should get trained while a user interacts with the system.
At this time it gets ~ 30 ...
- 101
0
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1
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99
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Suggestions on choosing correct method for multi-class classification of imbalanced data
I have data that is split into three classes (A, B and noise). The data amount is around 10000 samples, and A and B is only less than 5-10% of data. What is the best approach to handle this situation ...
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3
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930
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Which is the best classifier and with what performance measures?
I tried to implement a Classifier comparison like in the scikit-learn for text classification.
I used an 81 instances as a training sample and a 46 instances as a test sample. I tried several ...
4
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1
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2k
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Which are the suitable classification algorithms when the number of categories are more than 1000
Combination of categories is not possible as each class is a distinct brand.
One similar challenge was classifying objects using images (link below) but I could get any specific direction from few ...
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430
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How to operate on a count dataset (positive whole numbers with a lot of zeros) using neural networks for classification?
So i have some dataset, which is basically a count dataset. I have my own code for the classification using neural networks. Turns out that the data does not have a lot of correlation so accuracies as ...
4
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1
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1k
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Help interpreting formula for multi-class hinge loss
As I'm reading from wikipedia, and this Cross Validated question: Gradient for hinge loss multiclass, the gradient value for a training feature set is somewhat straightforward. However if I'm ...
- 211
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2
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How to represent no-detection in a confusion matrix
So let's say we have a multi-class classification problem and we want to represent the outcomes as confusion matrix. All the examples I'm finding on the web asume that all the elements are detected. I ...
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0
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1
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2k
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MCC or F-measure, which measure is the best to represent multi-class confusion matrix
I'm building a classifier of multi-class problem. In my context I have to classify vehicles into five categories: cars, vans, trucks, buses and motorcycles. I would like to use some measure to ...
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0
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1
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2k
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Multi-class SVM Calibration
Say we have multiple SVMs used in a one-vs-all approach, such that classes a, b, c correspond to 3 SVMs trained positively on the class and then negatively on all ...
- 315
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3
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269
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Multiclass classification question
I am working on applying Random Forests to a multiclass classification problem, where I have a set of 11 predictor variables and a response that can take the values of "Yes", "No", and "Maybe". In my ...
- 1,705
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2
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Can we compare classifier scores in one-vs-all/one-vs-many?
In a system where we perform multi-class classification via a one-vs-all technique, are two scores comparable? E.g.: If I have 0.5 and 0.6 on two different classifiers, is it possible to say that the ...
- 315
2
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2
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3k
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One-vs-many/One-vs-all - what value to use as probability?
I have constructed SVMs to do a one-vs-many approach to classification. Let's say I have 3 classes and I train 3 SVMs in a one-vs-many format. This gives me 3 SVMs each trained positively on one of a ...
- 315
2
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0
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876
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Why is my SVM multiclass classifier only correctly predicting a few classes?
I'm doing an online course to learn the basics of Machine Learning. This exercise is on how to use a SVM classifier with multiple classes. While the problem is specific to question 2 from this ...
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What are proper scoring and threshold selection rules for multiclassifiers?
I am using a neural network with 5 input neurons, 2 hidden layers of about 50 neurons in each layer, and 4 output neurons, trying to classify my 5-dimensional data into 4 different classes.
Currently,...
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3
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1
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Extracting weights from a classifier's posterior distribution
Given a classifier $C$ that gets text as an input and outputs a posterior distribution $p_1\dots p_n$ on $n$ possible topics.
In other words, for each user post, I have a list of probabilities $\{p_i\...
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2
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Quantify quality of multi label assignment
I am interested in quantifying how well a multi label assignment performs.
E.g. given 3 coloured boxes red, green and blue, with 20 likewise coloured balls in each.
A monkey is handed all the balls ...
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7
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1
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2k
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Multi-class classification easier than binary classification?
I have 10 different classes in my classification problem. Each class has about 200 instances, with more than 10.000 features. I performed the classification using Multinomial Bayes classification. ...
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True positive, false negative, true negative, false positive definitions for multiclass-multilabel classification?
I'm trying to apply some evaluation metrics to several clustering methods. I thought that I knew them basing on the multiclass confusion matrix, considering the rows as the actual classes and the ...
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4
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19k
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Matthews correlation coefficient with multi-class
Matthews correlation coefficient ($\textrm{MCC}$) is a measurement to measure the quality of a binary classification ([Wikipedia][1]). $\textrm{MCC}$ formulation is given for binary classification ...
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Multiclass vs. One-vs-All vs. One-vs-One classification
I am working on a classification problem with 7 classes. Is there any rationale to suspect that the best model might be found with a multiclass classifier, multiple one-vs-all classifiers, or even a ...
- 10.4k
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1
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how to make new class from the test data in machine learning
I have a list of accounts as data set and I need to group the accounts that refer to the same user using many features.
I'm thinking to use machine learning( but I'm new in this domain), because I ...
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