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Questions tagged [preprocessing]

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Pre-processing on MRI images

I have MRI images of brain tumors collected from a hospital (not a benchmark dataset). And I am planning to use them to predict/classify tumour types using a typical machine learning approach: texture ...
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1answer
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LSTM for prediction of next location step - help with standardization

I have a few questions regarding the topic and I hope someone might have experience with any of them. What I am trying to do is train an LSTM network, whose input is a sequence of N steps in a XYZ ...
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Specific data formatting techniques for discontiguous time series?

I'm facing a predicting problem for food alerts. The goal is to predict the variables of the most probable alert in the next x days (also any information I could get about future alerts is really ...
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Loading Data into DW: Direct Insert from PreProcessing vs PreProcess and then loading from CSV files

I have a preprocessing script (google cloud function) that generates files (stored in Google Drive). I want to load those files in my DW (Big Query). What are the pros and cons of: 1) Running the ...
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1answer
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Encoding multiple observations from the same feature space

My data contains multiple observations of categorical feature.The feature space is medical symptoms, so the data for this feature is like : ['fever','pain','yellow skin' .... ] .The amount of symptoms ...
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Image normalisation methods

I have found some research papers specifying explicitly the normalisation technique they used to get the results. What difference do IMG /255.0 And ...
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6 views

How to preprocess stereo audio data for a CNN?

I'm working on a deep learning project that whose data consists of stereo wav files where differences between the left and right channel are important. From the research I've done, [mel]spectrograms ...
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0answers
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Remove attributes with missing values exceeding a given threshold in WEKA

I imported csv file into WEKA, i have features that have missing value that has missing value percentage of 70% or above, i want to remove these features by weka or also sort that features by missing ...
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Data preprocessing step

I have a question concern data preprocessing step. I have 5 tables (csv files) , should i clean them one by one before merging them into 1 dataframe? Or i merge them into 1 dataframe, then I clean the ...
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Preprocessing imbalanced features for deep learning

I have an imbalanced dataset containing some equally imbalanced features where many observations are stacked at 0% (note the log scales in the histograms here). The top row shows one of these features ...
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Should I concatenate one-hot vectors and real vectors as input feature?

I have a set of input features consisting of the following for each row of data: real vectors (1x128 dimensions, between [1,1000000000] ) one-hot vectors ( 1x168 dimensions, i.e. 7 days 24 hours ) ...
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1answer
29 views

Cleaning data automatically [closed]

Do you use automatic cleaning tools for data? I mean something similar to h2o.ai's auto ml function but applied to preprocessing data. Or do you always clean data 'by hand'.
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2answers
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data pre-processing before image classification

I'm working on a machine learning project, Images classification (shape: 100 x 100)-> (vector of 10000), I did some pre-processing before applying decision trees algorithm , I got an accuracy of 55 % ...
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Columntransformer multiple columns with vector inputs

This is perhaps more of a coding question than data science so apologies if this is not the right platform to ask this. My question is related to the sklearn's <...
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18 views

How to feed my categorical data into my model?

This may be a basic question, I have a categorical data and I want to feed this into my machine learning model. my ML model accepts only numerical data. What is the correct way to convert this ...
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0answers
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How to pre-process large data for company prediction?

I have a dataset which is for 20 companies. Each company has 15 branches in 15 cities. A company has data for each branch. Each branch data is like below: ...
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1answer
33 views

What is the the cost of combining categorical variables?

I have 2 categorical variables e.g. state and city. Missing are only in city. As opposed to throwing out all observations with missing values for city or throwing out city all together I was ...
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1answer
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Does discretization of continuous features also lose information about distance?

During discretization, it "squashes" nearby values into one bin, losing a little bit of information along the way. But doesn't it also lose information about distances of features? For example, if we ...
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Address Class-Imbalance Dataset using Sampling Techniques on Train, Test Dataset or Both?

I am dealing with an unbalanced dataset and I'm really confused if I should apply sampling techniques, like downsampling, smote, upsampling etc., on the train, test dataset or both? The minority ...
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2answers
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Transformation of categorical variables (binary vs numerical)

When using categorical encoding, I see some authors use arbitrary numerical transformation while others use binary transformation. For example, if I have a feature vector with values A, B and c. The ...
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1answer
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Is it correct to use non-target values of test set to engineer new features for train set?

Suppose, I have a dataset with a feature_1 value and a target value. Now, I want to engineer a new feature by creating relative value by subtracting mean from each value. Question: Can I (1) use ...
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1answer
54 views

LSTM - How to prepare train from a dataset which contains multiple observations for different events

I m using LSTM in a project related to MobiFall dataset which contains falls and daily activitives - such as walking, sitting etc - sensed by accelerometer, gyroscope and orientation sensors in x,y,z ...
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67 views

How to deal with attributes that can vary arbitrarily for each sample?

Let's say we are trying to classify cars into five different categories. For this, we have a lot of samples described by color, brand, model, year of manufacture and so on. For instance, imagine ...
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How to deal with ordered set of values with different ranges

I have data to train a model on, a mix of continuous and categorical values, one column is labeled with values like "[0,10], [10,100], [100,500], [500,]". those are ...
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Audio signal signal processing for background noise reduction or removal

I am performing simple audio recognition using tensor-flow to spot key word or hot word detection. The graph takes the microphone input directly and performs "Audio spectrometer --> mfcc's --> and ...
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1answer
129 views

pandas: How to impute the categorical column by the nearest neighbors?

I've a categorical column with values such as right('r'), left('l') and straight('s'). I expect these to have a continuum periods in the data and want to impute nans with the most plausible value in ...
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2answers
45 views

Is there any tool for data visualization and manipulation?

I have a time series data set that I need to manually label them for supervised learning. What I am doing now is using excel to plot, and when I see the pattern that I want, I hover over the data on ...
0
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1answer
36 views

Missing Values in Classification

I'm working on a classification problem. I'm trying to build a model which can predict if a bank client will get a loan or not. Some of clients have co-borrower and the majority don't. I also have ...
2
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1answer
395 views

Difference between OrdinalEncoder and LabelEncoder

I was going through the official documentation of scikit-learn learn after going through a book on ML and came across the following thing: In the Documentation it is given about ...
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2answers
53 views

Can preprocessing the whole population cause data leakage?

Introduction I understand the problem of data leakage that could be caused by the preprocessing step when our training and test sets are just samples of an unknown population. The preprocessing ...
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0answers
28 views

Any tool that can help on manually label a time series data please?

i am working with a 10 years weekly financial time series data set, which has the standard format date open high low close volume. i would like to manually label (classify) the data set with label/...
2
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1answer
27 views

A single column has many values per row, separated by a comma. How to create an individual column for each of these?

As you can see below, I have a column called code with multiple values per row, separated by a comma. How can I create a column for each of these codes and make ...
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0answers
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How standardizing and/or log transformation affect prediction result in machine learning models

I recently ran an elastic net model on my data. My predictors are mostly skewed. I found my model perform slightly better when I standardize on log-transformed data than standardizing on original data....
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0answers
34 views

Lowercase texts before tokenizing as pre-processing step for alignment

I am pre-processing some texts and I wonder what the best practice is when preparing your texts for word alignment. I don't know how aligners such as fast align and GIZA++ work under the hood, but I ...
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0answers
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Transposing a dataframe (time-series)

I'm working on event-forecasting problem for a supermarket, and the data frame I have looks like (sorry for formatting): ...
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0answers
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ZCA preprocessing to CIFAR-10 dataset

I am trying to preprocess my CIFAR-10 dataset using ZCA technique. The code is give below ...
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1answer
885 views

StandardScaler before and after splitting data

When I was reading about using StandardScaler, most of the recommendations were saying that you should use StandardScaler before ...
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0answers
20 views

Normalize data with uneven groups?

I have a dataset with 3 independent variables [city, industry, amount] and wish to normalize the amount. But I wish to do it with respect to industry and city. Simply grouping by the city and industry ...
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0answers
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Are there some resources for filters specifically applicable in big data applications? [closed]

Are there some resources for filters specifically applicable in big data applications? Particularly, are there major differences between filter design for other domains and filter design for data ...
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4answers
59 views

When should ordinal data be represented catigorically and when as integer?

I am doing the Kaggle competition House Prices: Advanced Regression Techniques to learn more about data analysis. I would like to apply multiple models to the data(Regularized LR, Random Forests, ...
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0answers
33 views

Input data for this dataset to be feed into keras for training

Suppose I have 3 csv files which forms the dataset for training a machine learning model in Keras. file1.csv ...
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2answers
61 views

Preprocessing of Sudoku Dataset from Kaggle

Dataset: https://www.kaggle.com/bryanpark/sudoku I would like to create a neural network for this Dataset. Feature: ...
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2answers
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Basics: What is the correct sequence for preparing simple data for ML?

I'm just getting started with ML and am busy with my first Kaggle competition (the titanic one). I was just wondering what would be the best way to organise the data to avoid redundancy with the ...
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Does it make sense to preprocess (normalise or standardise) this data for GAN?

I'm working on a project where I have a dataset for a dynamical system (pendulum) containing a trajectory, energy cost and corresponding control actions (See below). I'm using a generative adversarial ...
0
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1answer
98 views

How to interpret Hashingvectorizer representation?

I cannot really understand the logic behind Hashingvectorizer for text feature extraction. I can follow the logic of Bag of Word or TFiDF where the features are values for all/certain words/N-grams ...
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0answers
15 views

Preprocessing during training and scoring of LSH

I am using LSH algorithm given in Spark. The dataset I am using has both numeric and categorical columns. Hence before training ...
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1answer
42 views

Feature importance over a subset of instance space instead of an entire instance space

I'm really curious if anyone has faced this problem before, or is it even widely studied at all. Imagine we have a feature that isn't important (based on many widely available and textbook feature ...
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2answers
42 views

What to do if my target variable is column of lists? [closed]

How I can transform my target variable(Y)? As it is list, I cann`t use it for fitting model, because I must use integers for fitting.
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0answers
49 views

Encrypt a data of single column of csv file in Nifi

I want to encrypt one column of my file which is present in local.What all processors will be required to fetch one column and also for encryption. I am new to Nifi. So, Any leads would be ...
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2answers
291 views

How to detect phrases from an English sentence.

The question is not about detecting keyphrases. It is about detecting a combination of words makes a valid phrase or not. For example, "John reads New York Times in New York." Here, the phrases ...