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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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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506 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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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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Multiclass Classification with Categorical Predictors

I have a data set consisting of 954 observations of 14 variables. The target variable is categorical with 3 classes. However, 12 out of the 13 predictors are categorical variables, so I have converted ...
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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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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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91 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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373 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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317 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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258 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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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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853 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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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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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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139 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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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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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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671 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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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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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
108 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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742 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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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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686 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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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
875 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
362 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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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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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 ...
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Can regression and classifiers both be checked for accuracy?

As much as I know regression is used for forecasting and we use R square to know how the model better fits, it. Unlike classifiers where we separate two sets and then use it for predicting the new ...
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How does Support vector machine predict the classes for the test points? [duplicate]

Could any body explain that " how does linear svm work for prediction in the classification process?" Many thanks,
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What are the signs that a classification just wont work?

Basically, I've a simple question: Are there signs which tells me that I just can't classify my data? To make things clear, I've a dataset whereby i try to predict the amount of tires changes. But ...
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1answer
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Missing features for classification [closed]

I dont have a collection of data which I try and extract features from. I have a set of real world experiments from which features are retreived. If the tests are sparse and I received missing data - ...
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548 views

How to do classification without class labels?

I am comparing different classification and clustering methods for analyzing my game (called Memori) data. It is about diagnosing kids with VSMD. I have fount a dataset from 1980s with only 2 ...