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 variable behavior which can be studied by statistics.

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878 views

bag of words in an online configuration, for classification / clustering

I have a set of image documents. I extract text keywords from this images using OCR to represent each image as a bag of words (a vector where each value is the number of occurrence of a word in the ...
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3answers
84 views

Tricky Interview Question [closed]

I was recently given an interview, and given the following scenario: You have one classification problem to solve. You can use either of the following 1) linear regression algorithm 2) Neural ...
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348 views

My neural network will run okay, but occasionally (every 1000) it provides an error. [closed]

I am using a neural network to forecast the direction of gold prices. I have created a neural network neuralnet within R. My programme runs well and i can get a prediction accuracy of about 51%. ...
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Classify strings having centers already found in python? [closed]

On StackOverflow suggested me to ask this question here. I'll copy it. I have a list of binary strings and two center strings which are not in the list. I would like to classify that list around the ...
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1answer
617 views

Multiple digits MNIST and transfer learning [closed]

I have a sample of 50,000 images, some of which are shown below: $\qquad$ $\qquad$ $\qquad$ $\qquad$ Associated to these images are labels for the digit with the largest pixel size. My goal is ...
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1answer
219 views

How to interpret the ROC curve on a binary classifier that always predicts 0?

Suppose we have a binary classifer that always chooses 0 no matter what. In this case, the ROC curve will be a horizontal line with AUC equal to 0.5. My question is, if we have such a curve, does it ...
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1answer
112 views

How could the result of a decicion tree (maximum depth) be converted to probabilities

I would like to compute a ROC-Curve for a decision tree created with sklearn based on the CART algorithm. Logically, if I compute it with maximum depth I always get a probability of 1 or 0 (discrete ...
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1answer
455 views

the accuracy formula of classification using lda

what is the formula of accuracy linear discriminant system as classifier? is the multi class and 2 class have same formula of accuracy? i tried to find it in google but cant find one, help me please ...
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677 views

Accuracy of K Nearest Neighbor in near-ties

Suppose you have a case where there's a near-tie in K Nearest Neighbor Algorithm - 3 of the K Nearest Neighbors are in class A and 2 of the K Nearest Neighbors are ...
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1answer
527 views

Imbalance Classification : How SMOTE handles majority class?

I'm working on Imbalance Classification problem with minority class(0.017%). I've read that imbalance classification can be handled using Undersampling, Oversampling and SMOTE. Major drawback of ...
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2k views

When would it be appropriate to use CNN vs. DNN?

I guess the common rule of thumb when choosing between CNN vs. DNN is if it has to do with images choose CNN and data points for DNN. But what if input images are pretty small.. in my case (33,45,3)...
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Is applying Clustering and then Classification good approach to solve multi-categorical classification problems?

Like for following Data Example: Let's assume I have following T-Shirt size categories: Training Data set: ...
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Classifying 8 objects based on 3 attributes [closed]

I had 8 objects and asked 80 people to score them on three attributes, say A, B, and C. Now I want to check if these 8 objects can be classified into categories based on the similarity between the ...
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2answers
2k views

Support Vector Machine - Classification or Clustering

I don't really understand if SVM are classification methods (like Logistic regression) or clustering methods. Since it's used for supervised learning, it should be part of classification methods ...
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1answer
754 views

Selecting features for improving classification accuracy [closed]

I have a dataset in which each sample has around 500 features. I know that in this feature set, some attributes are useful and may positively improve the classification accuracy. But some attributes ...
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1answer
620 views

Stacking Ensemble Meta Learning Components

I have been learning about Ensemble Algorithms. Reading this paper, I want to know about the meta classifiers that work well with Stacking Ensemble Learning Algo, since this work just talks about ...
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xgboost parameters - how can we use max.depth parameter with binary:logistic objective

I'm new to xgboost package and here is the doc on the parameters of this library for your reference. My question is, logistic regression doesn't do binary splitting and build a tree unlike decision ...
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40 views

a good resource to study about 2 classification ways?

One of my friends has asked me a question and because I haven't been involved with clustering a lot, I decided to ask his question here. He says that: There are two classification ways : C4.5 and ...
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1answer
2k views

Classifying data in R [closed]

I'm using R and I want to use some type of machine learning technique (SVM, perhaps) to classify data. I have data that looks like this, for example ...
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2answers
148 views

Accuracy and Statistical Significance [closed]

According to experimental result, one approach (Semantic Similarity based custom classifier) has 10% better accuracy over the other (Naive Bayes classifier) in a single domain. I would like to couple ...
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1answer
507 views

Comparing two sets of pixels to determine whether they belong to the same object

I have two sets of data, and I want to know if the second set is sufficiently different from the first to be considered different. More specifically, I have a sample set A from a number of pixels in ...
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1answer
73 views

Calculate ratings

Say I have a dataset that contains Users & all the sites that each user visited & how often each user visited it. For example: ...
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1answer
126 views

Anyway i can improve this multi class classification result?

I am building a multi class classification model using SVM to predict the grade for essays. What can I do to improve the result especially for class 1 and class 3? Their precision and recall are ...
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2answers
137 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 ...
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1answer
92 views

clustering VS supervised classification, in the case of very small database

I'm trying to classify/cluster subjects according to 4 features in two classes: healthy and sick. Two things to know: I know the labels/classes of each subject + I only have 40 subjects (in total: ...
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1answer
485 views

Classification accuracy on multi classes

My target has 5 classes. My testing dataset has an accuracy of about 34%. Can I assume this is a reasonable model purely based on classification accuracy, since random guessing is 20%.
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Class variable, table and chisq.test functions question

1.-I am calculating the probability of default with Chi-squared test Null Hypothesis [chisq.test() function]. 2.- My dependent variable is "default" that has two values: 1 (applicant defaulted on ...
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1answer
330 views

Behavior segmentation using DBSCAN, K-means Clustering and time series clustering

I have web UI event data representing various uses case scenarios with multiple data entry points. I would like to build some sort of DBSCAN, K-means Clustering solution to come up with user behavior ...
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2answers
260 views

Sklearn - Choosing the right model for supervised learning/classification task [duplicate]

I am beginning to learn how to use scikit-learn and I have a hard time choosing the right model. Here is my dataset: I have 100 persons. Each person was measured ...
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1answer
44 views

Data classification to size related classes

I would like to classify my data set into several classes which have a size relation (between classes) using supervised learning. For example let's say I'd like to classify subjects in order to ...
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1answer
938 views

Can we make the machine learn Gates (OR AND XOR etc.)

Below is the NAND Gate truth table, there are 2 independent features A,B and one dependent feature Y in the dataset. Can we make the machine learn this if YES how ? if No why ? Please go through ...
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1answer
38 views

how to predict how many years stay in college?

I have a data set to predict how long in years does a student stay in college. The dependent has value like 0.5, 1, 1.5.etc,. I used classification methods like SVM, decision tree but the accuracy is ...
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2answers
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How can I deal with dictionary-like data for classification?

Recently I got an interesting dataset, it looks like this: | user | ip_set | label| | user1 | {ip1,ip2,ip3,ip4} | 0 | | user2 | {ip1,ip2...} | 1 | The purpose is ...
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I have a classification problem where some of the columns/features have more than 90% null values. How do I handle them?

In my classification problem, some of the features(~5) among 85 features have mostly null values (>90%). How do I handle these values? Do I, 1) Ignore these columns/features altogether 2) Try and ...
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1answer
170 views

Principal component analysis on signal … dealing with replicates

I have a spectrum data (wavelength(x) versus absorption(y)) for 25 unique samples that is almost exactly to the problem presented in this thesis: https://brage.bibsys.no/xmlui//bitstream/handle/11250/...
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1answer
180 views

Class similarity coefficient for kNN

In our group we are dealing with misplacement of items and we came out with a method derived from knn, but we are not sure if there is already some place where this was described. The method would be ...
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1answer
99 views

What is the end result of running a machine learning algorithm on a data-set look like? [closed]

So I'm reading some research papers on machine learning applied to classification algorithms and one of the steps in the algorithm psuedo-code says: "Obtain classification prediction P from machine ...
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1answer
689 views

Poor performance of binary classification with DCNNs

I am trying to create a binary classifier that will assess if a photograph is aesthetically pleasing or not. However, despite various experiments, I am struggling to create something that even reaches ...
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1answer
127 views

How to build a MultiLabel Classifier?

Please Someone could help me in my classification's problem ? I have a dataset described by 7 variables (x1,...,x7),i want to build a classifier that would be able to predict the outputs a, b, c for ...
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1answer
1k views

How to report cross validation?

When we use cross validation (for example 10 fold) I can obtain 10 sensitivity, specificity and accuracy measures and also 10 ROC curves with the associated AUC. What should I do for reporting my ...
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1answer
48 views

SVM Working in information retreival

I have some URLs and i have to extract some features from these URLs to filter out some desired URLs. I have to give input those filtered URLs to SVM so as to classify those URLs as relevant and ...
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1answer
113 views

Given a value, and a dataset with two classes, what is the probability that it belongs to each class?

I have a dataset of continuous values from 0.0-1.0 with two possible class labels (say 30% are 'red' and 70% are 'blue'). Given a random value between 0.0-1.0, I want to give the probability that it ...
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1answer
768 views

Why is Training Error lower than Testing Error during the First Epoch? [duplicate]

I am training a deep neural network for classification (specifically, a convolutional neural network for object recognition). I use mini-batches for my training, because I cannot fit the entire ...
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1answer
797 views

Training accuracy

I am learning how to use classification in Matlab and have a question on calculating the training and testing accuracy. I am testing my data on SVM algorithm. I am using crossval and found two ways of ...
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1answer
695 views

ROC / AUC for polynomial Labels

How can I calculate the Area Under Curve for a classifier of a polynomial label in Rapidminer? I could only find a performance operator for binomial labels that provides the AUC value.
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0answers
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How to compare features and classifiers which achieve perfect accuracy? [duplicate]

So I'm looking to compare different combinations of features and classifiers. But I'm getting a lot of combinations that achieve 100% cross validation accuracy. I'm trying to figure out how I would ...
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1answer
886 views

Does learning rate have additional meaning in logistic regression?

I try to implement logistic regression with auto-correcting learning rate and I am puzzled by the outcome. At some point the cost of the function gets bigger than previously (to focus on some numbers ...
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1answer
391 views

Binary bayesian classification

How do you construct a Bayes classifier for a binary target where it is assumed: $p(y=1)=\alpha$ and $p(x|y)$ both multivariate gaussian?
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1answer
170 views

Naive bayes classifier testing vector question

Lets assume that our binary class has five features x1,x2,x3,x4,x5 but the incoming test vector(x1,x2,x3,x4) has only four features .. How would we handle it in the Naive bayes classifier .. Do we ...
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1answer
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Why classification algorithms have very high error?

Let me explain more about my question: I have collected 2000 data as the following: age sex education residence music young male Primary_school east ...