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1500 questions
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3 answers

Human activity recognition using smartphone data set problem

I'm new to this community and hopefully my question will well fit in here. As part of my undergraduate data analytics course I have choose to do the project on human activity recognition using smartphone data sets. As far as I'm concern this topic…
Jakubee
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What are the most suitable machine learning algorithms according to type of data?

I am beginner to data science. I found that some machine learning algorithms perform better, when given particular kind of data(ie - numerical, categorical, text, graphical). I searched about this topic on the web, but no luck. I would like to know…
user158
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Imbalanced dataset in MLP classifier in python

I am dealing with imbalanced dataset and I try to make a predictive model using MLP classifier. Unfortunately the algorithm classifies all the observations from test set to class "1" and hence the f1 score and recall values in classification report…
Blazej Kowalski
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How do I approach a classification problem where one of the classes is defined by 'not any of the others'

Suppose that I am interested in three classes $c_1$, $c_2$, $c_3$. But my dataset actually contains several more real classes $(c_j)_{j=4}^n$. The obvious answer is to define a new class $\hat c_4$ that refers to all classes $c_j$, $j>3$ but I…
h3h325
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2 answers

What is the rationale for discretization of continuous features and when should it be done?

Continous feature discretization usually leads to lose of information due to the binning process. However most of the Top solutions for Kaggle Titanic are based on discretization(age,fare). When should continuous features be discretized ? Is there…
drichlet
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2 answers

Why my training and validation loss is not changing?

I used MSE loss function, SGD optimization: xtrain = data.reshape(21168, 21, 21, 21,1) inp = Input(shape=(21, 21, 21,1)) x = Conv3D(filters=512, kernel_size=(3, 3, 3), activation='relu',padding='same')(inp) x = MaxPool3D(pool_size=(3, 3,…
sp_713
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4 answers

Improving accuracy of Text Classification

I am working on a text classification problem, the objective is to classify news articles to their corresponding categories, but in this case the categories are not very broad like, politics, sports, economics, etc., but are very closely related and…
ac-lap
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Can training label confidence be used to improve prediction accuracy?

I have training data that is labelled with binary values. I also have collected the confidence of each of these labels i.e. 0.8 confidence would mean that 80% of the human labellers agree on that label. Is it possible to use this confidence data to…
Ben J. Hawkins
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1 answer

Using SVM as a binary classifier, is the label for a data point chosen by consensus?

I'm learning Support Vector Machines, and I'm unable to understand how a class label is chosen for a data point in a binary classifier. Is it chosen by consensus with respect to the classification in each dimension of the separating hyperplane?
gc5
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3 answers

Google prediction API: What training/prediction methods Google Prediction API employs?

The details of the Google Prediction API are on this page, but I am not able to find any details about the prediction algorithms running behind the API. So far I have gathered that they let you provide your preprocessing steps in PMML format.
Tahir Akhtar
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Deriving backpropagation equations "natively" in tensor form

Image shows a typical layer somewhere in a feed forward network: $a_i^{(k)}$ is the activation value of the $i^{th}$ neuron in the $k^{th}$ layer. $W_{ij}^{(k)}$ is the weight connecting $i^{th}$ neuron in the $k^{th}$ layer to the $j^{th}$ neuron…
Neil Slater
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3 answers

Why do we use a Gaussian kernel as a similarity metric?

In graph-based clustering, why is it preferred to use the Gaussian kernel rather than the distance between two points as the similarity metric?
zfb
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3 answers

Why use convolutional NNs for a visual inspection task over classic CV template matching?

I had an interesting discussion come up based on a project we were working on: why use a CNN visual inspection system over a template matching algorithm? Background: I had shown a demo of a simple CNN vision system (webcam + laptop) that detected if…
JDS
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6 answers

NLP: What are some popular packages for multi-word tokenization?

I intend to tokenize a number of job description texts. I have tried the standard tokenization using whitespace as the delimiter. However I noticed that there are some multi-word expressions that are splitted by whitespace, which may well cause…
CyberPlayerOne
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Why k-fold cross validation (CV) overfits? Or why discrepancy occurs between CV and test set?

Recently, I was working on a project and found my cross-validation error rate very low, but the testing set error rate very high. This might indicate that my model is overfitting. Why does my cross-validation not overfit while my test set…
user7117436
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