Questions tagged [machine-learning]

Methods and principles of building "computer systems that automatically improve with experience."

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Transforming Data for Classification

I have a dataset of the type: Time_from_anchor is the time from when the diagnosis was made, if he had cancer. i.e patient 1 was diagnosed with cancer at 0. He had tests x and y at time -1 and tests ...
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BatchNorm vs InstNorm from the perspective of feature distributions

What I understand so far... The main purpose of BatchNorm is to overcome covariance shift -- more specifically what the authors of BatchNorm coined "internal covariance shift". Covariance shift is ...
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Why are ROC curves better for imbalanced datasets?

I have recently read this: " AUC(Area Under Curve) is good for classification problems with a class imbalance. Suppose the task is to detect dementia from speech, and 99% of people don’t have ...
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25 views

Graph Neural Network (GNN) code example

Can someone provide an implementation example with Tensor Flow or with Keras for a simple GNN?
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Learning rate Scheduler

A very important aspect in deep learning is the learning rate. Can someone tell me, how to initialize the lr and how to choose ...
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Different convolutions in CNN

I have a simple question. Why only convolution is used in CNN? There are a lot of possible rules for combining a filter and an image. Why is pixel-wise convolution the standard? For example, dropout ...
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Error on prediction keras multi_gpu_model

I've an issue running a keras model on a Google Cloud Platform instance. The model is the following one: ...
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78 views

How to draw neural network diagrams with this particular style?

I would like to draw a neural network architecture with the follow style. Do you know which tool can be used to do this? The paper is Operation-aware Neural Networks for User Response Prediction.
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Add faces (dynamically) to (pretrained) model for face recognition

Im very new to ML and there are loads that I do not understand about both implementation, theory and the math behind the CNNs. I have been looking at various models for face recognition, eg. VGGFace2 ...
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Why XGBoost regressor predicts behavior but not the amplitude?

I am very new to machine learning and I am trying to use XGBoostRegressor for my machine learning model (it has to do with physical modeling). I found out that it works very well for predicting the ...
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6 views

Is there any library available for Manifold learning using 'Diffusion map' in python?

I would like to use an unsupervised learning with technique called 'Diffusion map based manifold learning' in python. The original paper on diffusion map is here. I have already checkout pydiffmap ...
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Why when I apply GaussianBlur in my images, my model overfit? CNN KERAS

I have 1400 images (700 each class), and i'm using vgg-16 to classificate between one and other class. But when I apply the preprocess method Gaussian Blur (which seem to be very much clear to see the ...
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38 views

Why labels are not used in outlier detection algorithms?

I read this article from sklearn: https://scikit-learn.org/stable/modules/outlier_detection.html While these algorithms are very useful for outlier detection, I'm surprised to see that they are not ...
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How to save a trained ml model(e.g. decision tree) in database and load it using Flask to predict user submitted data?

I have tried the following way. It worked, but it is giving a different prediction in Flask vs Jupyter (which is correct) ...
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Activation Functions in Neural network

I have a set of questions related to the usage of various activation functions used in neural networks. I would highly appreciate if someone could give explanatory answers. Why is ReLU is used only ...
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1answer
17 views

Time Series Classification for 1 hour blocks

I am doing some analysis on time series. The time series would consist of 3 channels and contain 5 minute interval data. What I want is to be able to give it a 1 hour block of 5 minute interval data ...
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22 views

Classifying objects in video without machine learning

Recently, Nick Bourdakos posted a series of videos demonstrating bottle detection in a video stream using Tensorflow.js. Specifically, he is using SSD-mobilenet. The problem could be summarised as ...
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Is there any optimal way on feature selection for more than one classification algorithms?

I have a wine dataset with 13 features that indicates 3 different wine classes (target), and k-NN, SVM with linear kernel and SVM with rbf kernel algorithms to be tried with this dataset. My goal is ...
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27 views

Is it a best practice to exclude retweets from the data set?

I am going to build machine learning algorithm to identify fake tweets. The data set has huge retweets which I think might be an issue. Do you think given that the focus is the original tweet, it is ...
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39 views

CNN implementation low accuracy on MINST data

I'm trying to implement VGG11 (Model A of Table 1 from https://arxiv.org/pdf/1409.1556.pdf) on the MINST dataset but I'm getting ~10% train & test accuracy (as bad as random guessing). I had to ...
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1answer
32 views

Predicting Sequence based on Tabular Features

I have a dataset regarding a specific junction on a piece of road and the cars that will cross that junction. I am trying to predict the order that cars will pass the specific junction given a set of ...
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13 views

Testing if a sample fits into an existing cluster

I have a sample of data I'd like to create a model from, which would create N clusters. After the fitting to clusters, I'd like to test various samples against the existing clusters, seeing if the ...
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98 views

Correlation Matrix for non-numeric features

Currently, I have dataset with numeric as well non-numeric attributes. I am trying to remove the redundant features in the dataset using R Programming Languages. Note: Non-numeric attributes cannot ...
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109 views

What is the advantage of positional encoding over one hot encoding in a transformer model?

I'm trying to read and understand the paper Attention is all you need and in it, they used positional encoding with sin for even indices and cos for odd indices. In the paper (Section 3.5), they ...
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1answer
39 views

How to calculate accuracy, precision and recall, and F1 score for a keras sequential model?

I want to calculate accuracy, precision and recall, and F1 score for multi-class classification problem. I am using these lines of code mentioned below. ...
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73 views

ML, Statistics and Mathematics

I have just started getting my hands wet in ML and every time I try delving deeper into the concepts/code, I face the challenges of the mathematics and its cryptic notations. Coming from a Computer ...
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Using a trained classifier in an Android app

As the title suggests, I'm attempting to train some different classifiers into an android app. The main question I have is how to represent the different models in a neat and effective way, from ...
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25 views

Classification - Divide the interval (0 - 1] to lets say 100 classes and use each class to make a calculation

class-1 represents 0.01, class-i represents 0.01*i, class-100 represents 1.00. Thus, when the classifier predicts the class-y and it should have predicted class-(y+1) there is a small error so we can ...
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27 views

How to optimize input parameters given target and scoring parameters

I'm new to machine learning/optimization, so I apologize in advance if this has been answered before. I don't know which search terms to use. I have a large dataset where I have a number of input ...
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18 views

Covariates in machine learning classificatoin

I would like to classify a number of people as sick and healthy. I have all the body measures as features. I have to control for age and sex because body features are affected by that. How do I adjust ...
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18 views

Choosing a threshold based on the likelihood ratio test

I am stuck with a task of ratio test. Please help me with some advice. We are studying the Linear Discriminant Analysis. After projecting all the points on to "best" line the entire 2D dataset becomes ...
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17 views

Reverse of Yeo Johnson variable transformation done by preprocess function in caret package to get original Target and predicted values

I have done a Yeo Johnson transformation by using preprocess from caret package. I have predicted the Target Variable using linear regression. Now I want to reverse the transformation for both the ...
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1answer
32 views

Machine learning in electrical circuit simulation [closed]

In the field of VLSI design, and specifically in digital circuits it is common to use electrical simulation software to find signal integrity issues. I would like to use machine learning instead of ...
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33 views

classifier predicts only one class [closed]

I have a classification that has to predict three different classes: gcc,icc, clang. The prblem is that if I use a blind test set to do a submission, when I look athe the prediction I have on it I ...
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6 views

Given a list of thresholds in descending order will the corresponding FPRs and TPRs lists always be in ascending order?

I've made a series of predictions with a machine learning model. I have a list y of labels and a list p of predicted ...
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How do I find a softmax function to tell me how likely each input is

I am new to machine learning and neural networks. I have the following data, the X is a vector 5,1 and Y is just 1,1. with this first set of X (3/11/2019), the 5th number 93 is the closest to the Y ...
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43 views

K fold cross validation reduces accuracy

I am working on a machine learning classifier and when I arrive at the moment of dividing my data into training set and test set Iwant to confron two different approches. In one approch I just split ...
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1answer
34 views

Doubt in Derivation of Backpropagation

I was going through the derivation of backpropagation algorithm provided in this document (adding just for reference). I have doubt at one specific point in this derivation. The derivation goes as ...
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25 views

Andrew Ngs Class - Why Did He Change up the Cost Function?

I am taking Andrew Ng's Machine Learning Intro class. Looks like he changed the cost function without any explanation in the second week. Specifically: He no longer squares each deviation between the ...
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49 views

Why activation functions used in neural networks generally have limited range?

Why do we generally use activation functions with only limited range in neural networks? for e.g. $sigmoid$ activation function has range $[0, 1]$ $tanh$ activation function has range $[-1, 1]$ Q1) ...
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33 views

Data Analysis on normally distributed salary with Outliers

I have created normally distributed data with 2 outliers ...
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2answers
28 views

How to get an intution for generating Keras CNN layers for a model

I am going through tutorial for handwritten text recognition. And to do hand written digit recognition the author has constructed a Keras model as follows: ...
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28 views

Adding extra variables to XGboost model is worsening the train and test accuracy

I am fitting a multi class model using Xgboost. I am getting an accuracy of 96% on Train and 95% on test. I am using the 80-20 train/test split. However, when I am adding two new features , the ...
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15 views

error when submitting machine learning project

I am trying to make a submission of a machine learning classification problem. I have a test dataset where to try my model. To submit I have to build a csv file. The prblem is that when I go building ...
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Python Neural Network choose correct text

Hey I am new into the neural network scene. I would like to create a network which takes as input several file names. To train it I would say which files are usable and which are not. For example: ...
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53 views

Frequency/Count encoding

How do I perform frequency/count encoding for a train and test set? The implementations of this encoding I've seen simply frequency encode the categorical variables on a particular dataset (no ...
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1answer
43 views

How can different classification algorithms expressed as neural networks?

I have heard that each of the different classification algorithms can be expressed as a neural network architecture. How can the different algorithms like Logistic Regression, SVM(Support Vector ...