Questions tagged [classification]

In machine learning and statistics, classification is the problem of identifying which of a set of categories a new observation belongs to, on the basis of a training set of data containing observations whose category membership (label) is known.

In machine learning and statistics, classification refers to the problem of predicting category memberships based on a set of pre-labeled examples. It is thus a type of supervised learning.

Some of the most important classification algorithms are support vector machines , logistic regression, naive Bayes, random forest and artificial neural networks .

When we wish to associate inputs with continuous values in a supervised framework, the problem is instead known as . The unsupervised counterpart to classification is known as (or cluster analysis), and involves grouping data into categories based on some measure of inherent similarity.

7859 questions
2
votes
0 answers

PCA or Linear Discriminant Analysis ? Classification Problem in QoS

I'm working on a classification problem related to the marking of ip/tcp packet, the classes are Best Effort and Non Best Effort; I'm using Python language. I have selected these features: Protocol, Length of the packet, Port number used for source…
2
votes
1 answer

TF estimator gradient boosted classifier suddenly stopped while training

I have trained gradient boosted classifier with TF exampled code https://www.tensorflow.org/tutorials/estimators/boosted_trees_model_understanding but, TF estimator gradient boosted classifier suddenly stopped while training I think it takes several…
2
votes
2 answers

Is there a maximum number of classes I can train in keras?

Hey i train a neural network with keras. I have 14 categories. Everything works and there is no error. But when I look at the result I see that the last 3 trained categories are completely wrong. No testobject is connected to the 3 categories. I…
Blümchen
  • 21
  • 1
2
votes
1 answer

Per class weighted loss for multiclass-multilabel classification

I'm doing multiclass-multilabel classification. Namely, I have N_labels fully independent labels for each example, whereas each label may have N_classes different values (mutually exclusive). More concretely, each example is classified by…
Mike E
  • 43
  • 7
2
votes
0 answers

Image classification and image resizing

I have a set of images that I am using for a typical classification problem using Tensorflow. The images come in different sizes so I wrote a small piece of code to resize them all. But the question is what is the best strategy of resizing for…
2
votes
0 answers

NLTK: How to define the "labeled_featuresets" when creating a ClassifierBasedTagger with nltk?

I am playing around with the nltk right now. I am trying to create various Classifiers with nltk, doing named entity recognition, to compare their results. Creating n-gram Taggers was easy, however I have run into some issues creating a…
2
votes
0 answers

How to choose metrics for evaluating classification results?

Recently we have developed a python library named PyCM specialized for analyzing multi-class confusion matrices. A parameter recommender system has been added in version 1.9 of this module in order to recommend most related parameters considering…
2
votes
1 answer

How to find the wrong predictions in Keras?

I have built a Keras model for extracting information from a raw input of text input. I am getting an accuracy of 0.9869. How can I know which of the training data is making the accuracy go low? I have pasted the code I am using below. import numpy…
2
votes
1 answer

How would a multiple output classification neural network work?

I currently understand and made a simple neural network which solves the XOR problem. I want to make a neural network for digit recognition. I know using MNIST data I would need 784 input neurons, 15 hidden neurons and 10 output neurons (0-9).…
2
votes
1 answer

element 0 of tensors does not require grad and does not have a grad_fn

I am trying to apply reiforcement learning mechanism to classification tasks. I know it is useless thing to do because deep learning can overperform rl in the tasks. Anyway in research purposes I am doing. I reward agent if he's correct positive 1…
JaeJu
  • 85
  • 1
  • 11
2
votes
1 answer

Is there a difference in computation according to input shape? (CNN in Python with Tensorflow)

I am solving a text classification problem by reference to the paper(Kim, 2014). And then I found between below two models, the model on the left(Model 1) takes about 2.5 times more time than the model on the right(Model 2). I think the number of…
2
votes
2 answers

Unify text and image classification (Python)

I am working on a code to classify texts of scientific articles (using the title and the abstract). And for this I'm using an SVM, which delivers a good accuracy (83%). At the same time I used a CNN to classify the images of these articles. My idea…
2
votes
2 answers

How to oversample to fix class imbalance in time series data?

I have a time series with hourly frequency and a label per day. I would like to fix the class imbalance by oversampling while preserving the sequence for each one day period. Ideally I would be able to use ADASYN or another method better than random…
JHall651
  • 427
  • 1
  • 4
  • 15
2
votes
1 answer

Why I need pre-trained weight in transfer learning

I'm learning transfer learning with some pre-trained models (vgg16, vgg19,…), and I wonder why I need to load pre-trained weight to train my own dataset. I can understand if the classes in my dataset are included in the dataset that the pre-trained…
2
votes
2 answers

Finding label-specific top features for non-linear classifier

Is there any function that gives the top features of each label in a Random Forest/ XG Boost classifier? The classifier.feature_importances_ only gives top features for the classifier as a whole. Looking for something similar to the classifier.coef_…
1 2 3
99
100