Questions tagged [data-preprocessing]

For questions related to the concept of data pre-processing, which includes, for example, cleaning, instance selection, normalization, transformation, feature extraction or selection.

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10 views

How is the performance of a CNN trained with monochrome images on image recognition tasks degraded?

For CNN image recognition tasks, like object recognition/face recognition/object segmentation/posture recognition, are there experiment results about how much will the performance be degraded with ...
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10 views

Should I use keras or sklearn for PCA? [migrated]

Recentl I saw that there is some basic overlapping of functionality between keras and sklearn regarding data preprocessing. So I am a bit confused that whether should I introduce a dependency on ...
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19 views

How can I predict the label given a partial feature vector?

Most of the traditional machine learning algorithms need a feature vector of a constant dimension to predict the label. Which algorithms can be used to predict a class label with a shorter or ...
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2answers
48 views

How to train a neural network with a data set that in which the target is a mix of 0-1 label and numeric real value label?

I am running into an issue in which the the target (label collums) of my dataset contain a mixture of binary label (yes/no) and some numeric value label. The value of these numeric value (resource 1 ...
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1answer
32 views

Can I find a mapping that minimizes the maximum distance ratio of certain vectors?

Let's say we have several vector points. My goal is to distinguish the vectors, so I want to make them far from each other. Some of them are already far from each other, but some of them can be ...
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17 views

How does sampling works in case of imbalanced image datasets?

I am solving a problem of image classification of the image dataset for 3 classes. Dataset is highly imbalanced. How will sampling (either over- or under-sampling) work in that case? Should I remove (...
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14 views

How to feed key-value features (aggregated data) to LSTM?

I have the following time-series aggregated input for an LSTM-based model: ...
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1answer
83 views

How to fill missing values in a dataset where some properties can be inputs and outputs?

I have a dataset with missing values, I would like to use machine learning methods to fill. In more detail, there are $n$ individuals, for which up to 10 properties are provided, all numerical. The ...
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1answer
32 views

Are my steps correct for a proper classification of a sick brain?

I have a dataset with MRI of patients with a specific disease that affects the brain and another dataset with MRI of healthy patients. I want to create a classifier (using neural networks) to ...
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22 views

What pre-processing of the image is needed before feeding it into the convolutional neural network?

I can't figure out what preprocessing of the image is needed before feeding it into the convolutional neural network. For example, I want to recognize circles on a 1000 by 1000 px photo. The learning ...
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18 views

Do we scale our target feature in regression problems?

I know this is a basic problem, but still could not find answer, I feel like most books/tutorials avoid talking about scaling the output feature instead they just mention scaling input features. So ...
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18 views

Are there any general guidelines for dealing with imbalanced data through upsampling or downsampling?

Are there any general guidelines for dealing with imbalanced data through upsampling/downsampling? This Google developer guide suggests performing downsampling with upweighting, but for the most ...
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17 views

How can raw data from a motion sensor (like an IMU) reduced to the main points of the data

How can I reduce the caputured movement data of a person in a way, that I have filtered the main features of the movement. Or how can I detect pattern/ main features in that data set? I captured some ...
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48 views

How can I group the entries of the network traffic by their similarity?

I have the traffic of my network (with hundreds of entries). Below I am showing only 9 entries. ...
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10 views

How should I deal with multi-dimensional tensors for nodes in a graph convolution network?

How to work with GCN when the features of each node is not a 1D vector? For example, if the graph has N nodes and each node has features of the form $C \times D \times E$. Also, is there an open-...
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1answer
46 views

Do I need to denormalise results in linear regression?

I have learned so far how to linear regression with one or multiple features. So far, so good, everything seems to work fine, at least for my first simple examples. However, I now need to normalise ...
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27 views

Do I have to downsample the input and upsample the output of the neural network when implementing the NICE algorithm?

Consider that my input is an RGB image. The size of my image is $N\times N$. I'm trying to implement NICE algorithm presented by Dinh. The bijective function $f: \mathbb{R}^d \to \mathbb{R}^d$ maps $X$...
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16 views

What is the difference between training a model with RGB images and using only the color channels separately?

What is the difference between training a model with RGB images and using only the color channels separately (like only the red channel, green channel, etc.)? Would the model also learn patterns ...
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2answers
43 views

Is text preprocessing really all that necessary for NLP?

As a first step in many NLP courses, we learn about text preprocessing. The steps include lemmatization, removal of rare words, correcting typos etc. But I am not so sure about the actual ...
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1answer
49 views

How should I deal with variable-length inputs for neural networks?

I am a very beginner in the field of AI. I am basically a Pharma Professional without much coding experience. I use GUI based tools for the neural network. I am trying to develop an ANN that receives ...
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22 views

Can the addition of low-quality images to the training dataset increase the network performance?

I already trained a deep neural network called YOLO (You Only Look Once) with high-quality images (1920 by 1080 pixels) for a detection task. The result for mAP and IOU were 93% and 89% respectively. ...
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1answer
71 views

How should I deal with variable input sizes for a neural network classifier?

I am currently working on a project, where I have a sensor in a shoe that records the $X, Y, Z$ axes, from an acceleration and gyroscope sensor. Every millisecond, I get 6 data points. Now, the goal ...
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1answer
61 views

Is it recommended to remove stop words before named entity recognition?

Removing stop words can significantly speed up named entity recognition (NER) modeling by reducing the number of tokens in a document. Are stop words critical to get correct NER performance?
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1answer
43 views

Using three image datasets with different image sizes to train a CNN

I've just started with AI and CNN networks. I have two NIFTI images dataset, one with (240, 240) dimensions and the other one with (256, 132). Each dataset is front a different hospital and machine. ...
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14 views

Language Learning feedback with AI

Is there a program under development that uses AI technology, like Siri, to "hold hands" so to speak with a language learner and coach them on accent, colloqiual expressions, or to let them guide the ...
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1answer
29 views

Choosing Data Augmentation smartly for different application

I'm trying to understand the role of data augmentation and how it can affect the performance/accuracy of a deep model. My target application is fire detection (on video frames), with almost 15K ...
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1answer
35 views

How to automatically detect and correct false information in columnar data?

I'm working on data cleaning and I'm stuck. I have a data set with 3 columns: id, age, and weight. Supposing I have an entry: ...
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18 views

Acoustic Input Data: Decibel or Pascals

In acoustics decibel levels were defined to solve an issue with showing values that are interpretive, understandable, and easy to communicate in contrast to intensity or pressure in Pascals. $dB = ...
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0answers
12 views

EEG and Accelerometer Neural Network

I have frequency EEG data from fall and non-fall events and I am trying to incorporate it with accelerometer data that was collected at the same time. One approach is, of course, to use two separate ...
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0answers
9 views

Hashing images detects false duplicates

Like I said in the title, I used a code I found to identify duplicate images however there are many false alarms. Can someone give me a link to some code I could use that really works? The problem ...
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0answers
89 views

Suggestion for finding the stable regions in spiral galaxy data?

I am working with a data set that consists of the actual pitch angle (given as PA(Y)) and the pitch angle at each radii (listed from 1 to 217). In the image below, ...
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1answer
87 views

How to define the “Pre-Processing” in machine learning?

Is every process1 that is done on the data before we train the model is always called the pre-processing part? Or are there some processes which are not included? 1"Every process" is includes data ...
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27 views

Are there free and easy-to-use annotation tools for 3D bounding boxes?

Are there free and easy-to-use annotation tools for 3D bounding boxes? There is a lot of annotation tools out there, but most of them only good for 2d boxes.
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learning object recognition of primitive shapes through transfer learning problem

Question on transfer learning object classification (MobileNet_v2 with 75% number of parameters) with my own synthetic data: I made my own dataset of three shapes: triangles, rectangles and spheres. ...
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57 views

Focal loss for imbalanced multi class classification in Pytorch

I want an example code for Focal loss in PyTorch for a model with three class prediction. My model outputs 3 probabilities. ...
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1answer
44 views

How can I merge two datasets? [closed]

I want to merge 2 data sets in one, but don't know the right approach to do it. The datasets are similar, the last column is the same - will or not them buy a product. In the first dataset, users who ...
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1answer
266 views

What is “conditioning” on a feature?

On page 98 of Jet Substructure at the Large Hadron Collider: A Review of Recent Advances in Theory and Machine Learning the author writes; Redacted phase space: Studying the distribution of inputs ...
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15 views

What's the correct approach to standardise data from a time-series used for LSTM neural network predictions?

This question discusses the same model mentioned in Why is the value range of my LSTM model's prediction different from my test labels? Repeating the main points: I am using LSTM to do time-...
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3answers
78 views

How can I remove the noise from an EEG signal?

I am working on a project that takes signals from the brain and preprocesses them and then makes the machine learn about what human is thinking about. But I am struck in preprocessing of signal (...
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11 views

Is there any reason to believe a ml pipeline that works on dataset A will work on dataset B where both have similar meta features?

I’m working on generating an automl pipeline(a combination of data cleaning and transformation algorithms applied to a dataset then generate a model) that works on a new dataset by looking for past ...
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1answer
54 views

How to rescale data to its original range after MinMaxScaler? [closed]

I'm using sklearn's MinMaxScaler in order to scale my data down. However, it would be nice to be able to rescale it back to its original range. Is there any way I ...
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1answer
56 views

Why do we normalize data in a deep neural network?

I have asked this question a number of times, but I always get confusing answers to this, like "normalized data works better", "data lives in the same scale" How can ...
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1answer
45 views

Do I need to use a pre-processed dataset to classify comments?

I want to use Machine Learning for text classification, more precisely, I want to determine whether a text (or comment) is positive or negative. I can download a dataset with 120 million comments. I ...
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3answers
48 views

Are there tools to help clean a large dataset so that it only contains faces?

I have a fairly large dataset consisting of different images with and without persons that I want to use for a project. The problem is that I only want the pictures that contain faces, and it is best ...
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1answer
50 views

Is there an LSTM-based unsupervised learning algorithm to label a dataset of curves?

I have a big amount of light curves (image below). I am trying to label the points as signal or background (the signal appears usually periodically, several times, for a given light curve). More ...
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2answers
58 views

What is the impact of scaling the features on the performance of the model?

I am trying to generate a model that uses several physicochemical properties of a molecule (including number of atoms, number of rings, volume, etc.) to predict a numeric value $Y$. I would like to ...
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2answers
90 views

Which of these two numerical methods for z-score normalisation is preferable, in multivariate linear regression?

In the exercise Exercise 3: Multivariate Linear Regression, by Andrew Ng, the author suggests to "scale both types of inputs by their standard deviations and set their means to zero". $$x_{n e w}=\...
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1answer
74 views

When should I use feature learning as opposed to feature engineering?

With the advancement of deep learning and a few others automated features learning techniques, manual feature engineering started becoming obsolete. Any suggestion on when to use manual feature ...
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1answer
131 views

How should I encode the input which are 5 cards from a deck of 52 cards?

How should I design my input layer for the following classification problem? Input: 5 cards (from a deck of 52 cards) in a card game; Output: some classification using a neural network How should I ...
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3answers
160 views

Would this relatively small dataset be enough to train a CNN?

Scenario: I am trying to create a dataset with images of choice for different animal classes. I am going to train those images for classification using CNN. Problem: Let's assume I somehow don't have ...