Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [classification]

Statistical classification is the problem of identifying the sub-population to which new observations belong, where the identity of the sub-population is unknown, on the basis of a training set of data containing observations whose sub-population is known. Therefore these classifications will show a ...

-1
votes
0answers
8 views

text classification for labeling data antomaticly [on hold]

i have a list of keyword for class a and b and a data test that is in test description. Assign the class after matching the text description with keywords. if keyword from class A the Label A and ...
0
votes
1answer
11 views

How to construct a weighted classification system with a many-to-one relationship with the classifications

So I am at this hurdle in a project to where I can't seem to make any sense of. I have a scanning system. Let's say that it tracks widgets with 5 possible defects. Any widget can have 0 or all of ...
0
votes
0answers
11 views

Minimizing error is always good? [on hold]

I've got this question raised by my teacher that has been bugged me. Usually, we use learners in ML to minimize the classification error. On what situations minimizing the error is not the best ...
0
votes
1answer
13 views

How to deal with unknown classes with a neural network classifier? [on hold]

I have a small RNN with a softmax output, which succesfully classifies sequences within a known set of n classes. Now I have the problem that there might be sequences which do not belong to any of ...
0
votes
0answers
11 views

AUC/R^2 score strictly lower on partitioned dataset than total dataset

Suppose I've fit a logistic regression to my data and I calculate the AUC. I then partition my dataset according to one of the explanatory variables (say those rows where the variable value is greater/...
4
votes
1answer
223 views

Scale dummy variables in logistic regression

Let's say I have a data set that mixes categorical and continuous features and I would like to study the relative importance of each feature in the prediction of a certain class. For that I am using ...
0
votes
0answers
11 views

What algorithm(s) should I use for a regression training and a classification prediction?

I am trying to work on a project on MALDI-TOF MS dataset. The dataset contains mass-spectrometry data of pure samples (1 bacterium species) and mixed samples (mixtures in known proportions of 2 ...
-1
votes
0answers
14 views

What's the benefit of sphering? [duplicate]

What's the benefit of sphering? E.g. in the case of sphering labeled data and then doing nearest centroid classification?
0
votes
1answer
27 views

Imbalanced multiclass classification with many classes

I am working on a text classification project in which we have hundreds of (imbalanced) classes. Some characteristics of the data: We have examples of "bad" documents. Basically documents that don't ...
0
votes
0answers
6 views

Appropriate image classification method for different edge patterns

I have the following two categories of images. They are transformed edge detection histogram. As you can see, their patterns are subtly different. Thus, I wonder what kind of classification method (e....
0
votes
0answers
17 views

Different result while training in CPU and GPU for Google BERT

I was running few examples exploring the pytorch version of Google's new pre-trained model called the Google BERT. I ran the example in both CPU as well as GPU machines. I run the following code for ...
0
votes
0answers
19 views

how to map leaves in random forest to thire original y_test (target ) in the train set?

in RandomForestClassifier of sklearn.ensemble i try to understand hoe to map the obkect return from fit , for example in this code how to get samaples in the leaves and how to connect them to it's ...
-1
votes
0answers
10 views

Neural Network for sound classification under Matlab [closed]

I've been through this Matlab exemple on how to train a simple convolutional neural network for deep learning classification. The dataset used in this exemple is a digit image dataset. I've tried to ...
0
votes
0answers
20 views

Can I use svm.SVC for complex image classification?

I've been trying to implement the classical Cat vs dogs classifier using sklearn.svm.SVC. However, I wasn't able to have more than 51% correct ratio (which is ...
1
vote
0answers
24 views

Question about sample size for each class for machine learning classifiers

I'm trying to use a machine learning classifier (SVM in particular) on data that I generate. Unlike other applications, the data is not given to me but rather I have the flexibility to generate how ...
0
votes
1answer
13 views

Convolutional network - how to choose output channels number, stride and padding?

I am trying to create a convolutional network for image classification problem. I am using PyTorch but I have troubles in understending the implementation of their 2D convolutional layer. I understand ...
0
votes
0answers
14 views

Almost reverse feature importances by Extratrees vs RandomForest

I am using scikit-learn to find feature importances using ExtraTreesClassifier and RandomForestClassifier, both of which have feature_importances_ attribute. The ...
0
votes
0answers
14 views

How to compare model performance across subpopulations?

I'm trying to determine if a model I'm working with performs differently across subpopulations of the general population I'm training on. Let's say that my population $P$ is made up of three ...
0
votes
0answers
7 views

How to classify a new example after optimizing the SVM Primal with Kernels?

Suppose I have the optimal u vector and b bias term as defined in the top response by Firebug on this post Is Gradient Descent possible for kernelized SVMs (if so, why do people use Quadratic ...
0
votes
0answers
15 views

How do deep CNNs handle problem of “perceptual aliasing” while visual place classification?

Deep CNNs have achieved state-of-the-art performance in image classification. The underlying concept of place recognition is similar to image classification where the task is to classify or recognize ...
0
votes
0answers
12 views

Clustering as a method to find and label classes for supervised learning

I'm working on a text classification project. We have around 300k documents (small, 1~2 phrases) and we don't know the set of labels or how many labels there are. The recommended approach to me was ...
0
votes
0answers
12 views

How to perform One vs One (All vs All) Classification?

Say I have 4 possible classes (C1 to C4) and hence 6 possible models. My question is that in a model, say C1 vs C2, how am I supposed to handle training dataset when a given instance's class is ...
1
vote
1answer
24 views

Binary classification and target-label proportion

Suppose that we have a binary classification problem with a vector y = [1 1 0 1 0 0 1 ... 0] having the proportion: ...
0
votes
0answers
9 views

Correlation of fitness vs performance on an ensemble model analysis

I have data in the form (the following are just dumb values I use for presentation purposes): ...
1
vote
0answers
20 views

Did I fill out this F1-Score Interpretation Matrix correctly?

My goal is to make a matrix in order to help me better understand the F1-Score and interpred it correctly in a classification problem. Following my research I came up with this Matrix, but had trouble ...
0
votes
0answers
12 views

Multilabel classification problem where a number of output labels are in certain range

I am tackling a multi-label classification task. In this problem, we have 13 classes For one sample $x \in R^{20}$, $2 \leq |h(x)| \leq4$ Here, $h(x)$ means the prediction labels of sample x by ...
0
votes
0answers
10 views

Decision boundaries of LDA and logistic regression

In an exercise we had to draw the decision boundaries between two samples from two different classes for Linear discriminant analysis (LDA) and logistic regression (LR). I know how these two ...
0
votes
0answers
19 views

What are some methods to do early prediction of a classification problem?

I recently built a classifier for a company regarding detection of equipment failure. Currently, my model takes all the current features of the system, and predicts if the equipment is going to need ...
0
votes
0answers
12 views

Density trees for classification

I have a hard time understanding the concept of a density tree (not decision tree) for classification. My biggest problem is that I dont understand how the tree acutally classifies new data into the ...
0
votes
0answers
20 views

What is a good performance index in multi-classification problem?

I'm performing a multi classification model exploiting different statistical learning methods. In particular, I'm performing a classification in 3 different classes. I'd like to know if there exists ...
-1
votes
2answers
25 views

how to classify input image using clustering algorithm such as k-mean?

I want to classify cifar10 images using a clustering algorithm (k-mean). Each image in the cifar10 dataset has a label, so, the results must be a set of labels which are corresponding to the test ...
0
votes
0answers
7 views

Understanding the Gini/AUC metric as out-of-development performance metric

Assume we develop a model for a binary classification task that reaches a certain Gini/AUROC estimate on the validation ( or training ) sample, among others. This is an overall good metric, often used ...
0
votes
0answers
30 views

Test Set Probabilities and Accuracy [duplicate]

Say we've got a logistic regression model $M$ used as a classifier in a binary case. Now we take a test set $\tau=\{(x_1,y_1),...,(x_n,y_n)\}$, each test sample is assigned with $\hat{\pi}_i=P(y_i=1|...
1
vote
0answers
31 views

Bayesian classification using uniform distribution

I would like to ask you if my thought first and my answer then to the following problem is right. Suppose that I have a 3-class 1-dim classification problem where the classes $\omega_1, \omega_2, \...
0
votes
0answers
18 views

ML: High to filter noisy/non-noisy data? Or, how to get probabilities with each prediction?

I want to generate predictions using a train dataset. There is a lot of noise, and therefore I want to either 1. have confidences/probabilities for each prediction or 2. classifying data into noise ...
0
votes
0answers
14 views

Bagging - Strange result

Setting Training set size: 5200 Test set size: 1000 Question I'm currently working on a classifier which classifies images in a class (binary). My classifier uses a bagging approach (10 bags). I've ...
0
votes
0answers
8 views

Interesting class-assignment problem with temporally consistent counts

I have time counts that belong to multi-class categories. Data where a number of experiments was done or not. 0 means a negative outcome, 1 a positive outcome and N means the test was not done. Often, ...
0
votes
0answers
15 views

For what probability threshold do papers report sensitivity, specificity etc?

Usually, I just present the AUROC and the ROC curve for comparing classifiers, but a lot of papers present metrics like specificity and sensitivity in a table. Because these vary over the threshold ...
1
vote
0answers
51 views

K-Nearest-Neighbor classification with only distance/similarity matrices, is it possible?

I want to classify histograms/distributions using K-Nearest-Neighbor. I can measure distances/dissimilarities between the distributions (using euclidean distance, kullback-leibler divergence...), thus ...
0
votes
0answers
20 views

Understanding model performance

I built a multiclass (and very imbalanced classes) classifier. When evaluating I found an average F1 of .98 and the classifier seems to be working rather well. However, on evaluating the ROC and ...
0
votes
0answers
14 views

R: Which approach should I use to optimize goals to achieve best results based on historical data?

1- What I have I have a historical data, with the following datas per store (about 5.000 stores) (%) Mix of premium product over total product (per month) Monthly Goals setted for the (%) of this ...
2
votes
0answers
22 views

SVM classifier: strange location of support vector

I am playing around with Matlab's example which involves classifying whether data lie inside a circle of radius 1 (label: -1) or out of it (label: 1). I decided to experiment with things and flipped ...
-1
votes
0answers
9 views

Hidden Markov Models for non-sequential data

Can we use uniform probabilities for "A" transition matrix cause there isn't any meaning for consecutive here? For example, I'm trying to classify people if they were infected or no't so every row in ...
1
vote
0answers
10 views

What is an appropriate Evaluation Metric and corresponding Loss function which best optimize the metric for a classification based FAQ Chatbot?

I am developing a FAQ chatbot to display/return only one correct answer in a chat window for a given question from the user. I know MRR & MAP make sense as an evaluation metric for information ...
0
votes
1answer
47 views

How can I improve my classification model(s), when it gives training, cross validation and test accuracies all close to 68%-69% only?

I'm performing a binary classification with both logistic regression and SVM, where I've 80%-20% train-test split of the 10000 samples, each with 11 features. In my problem, the features are the data ...
0
votes
0answers
9 views

About choice of discrete class labels

I have not been able to find any answers or resources where it is mentioned whether the class labels should be 0/1 or +1/-1 and its effect on classification. I usually select 0/1 for binary ...
0
votes
0answers
13 views

Encoding variable number of categorical features

I have a dataset listing the software installed for each user. This dataset shall be used (in conjuction with other user datasets) to classify the user into 4 (imbalanced) categories. There are over ...
0
votes
0answers
45 views

K Fold Cross Validation in in KNN algorithm

I have a dataset with 2000, observations and 21 columns. Using KNN, I want to classify validating data using last column price_range which contains the ...
2
votes
2answers
36 views

How can I represent a randomForest object in a way that “unlocks the black box” in R? [duplicate]

I have a randomForest object in R, and am trying to extract prescriptive insights, as I would with a tree. This is for a binary classification problem. Given this setting, my main question is: How ...
0
votes
0answers
13 views

Training a perceptron on MNIST using whole images yielding perfect results

So I programmed a simple Perceptron algorithm to classify images from the MNIST dataset. My goal is to tell apart what image is a zero and what image is a one. First I trained my algorithm by ...