Questions tagged [preprocessing]

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1answer
629 views

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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0answers
48 views

binning high cardinality categorical features

one approach I have tried when preprocessing high cardinality categorical features (for example, US City) is to do a value count of all the values in the data, then take the top x most frequently ...
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0answers
22 views

Which one of these is the most efficient way to model training data for a neural network that will play a snake-like game?

I am building an AI using a neural network that will play Tron against a human player. The game consists of a board with fixed width and height where each player can move at any direction (except for ...
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0answers
115 views

Audio files and their corresponding spectrograms for image classification process

Suppose I have a dataset of audio files that I have to use for whale sound classification. I am choosing the strategy of treating it as an image classification problem by using their corresponding ...
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2answers
4k views

Loading own train data and labels in dataloader using pytorch?

I have x_data and labels separately. How can I combine and load them in the model using torch.utils.data.DataLoader? I have a dataset that I created and the ...
2
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1answer
76 views

Clustering time series based on monotonic similarity

Context I am involved in a task of clustering 1500 time series of 500 observations into a few number of clusters. The time series share all the same observed property at different spatial locations, ...
2
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2answers
203 views

How to extract and classify data from a column in excel?

I have a column in an Excel sheet that contains a lot of data separated by || delimiters. The data can be classified to some classes like Entity, IFSC codes, ...
2
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1answer
350 views

normalization/denormalization for linear regression problem

My question is simple actually, I have two features that have big difference in scale. So I used a simple normalization by dividing the scale=np.max(array) for both data and lables. Then after ...
2
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0answers
294 views

User activity representation for Prediction/ML

I want to predict future user activities (e.g., account cancellation) but I don't know how I'm supposed to represent the data. The raw data is a sequence of all activities by all users: ...
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0answers
17 views

How to deal with similar feature values but each indicates to a different information?

If I have a feature with replicated values but each of these values indicates a different piece of information. example: feature 'street name' with value 'A' which some of these 'A's are for Boston ...
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0answers
19 views

How to treat Compass data in random forest regression

I'm working on a project where two of the features are entryHeading and exitHeading. Both state the direction (N, NE, E, SE, S, SW, W) of a vehicle at multiple points. My question is how would i go ...
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1answer
33 views

Is it compulsary to normalize the dataset if doing so can negatively impact a Binary Logistic regression performance?

I am using raw data set with 4 feature variables to do a Binominal Classification using Logistic Regression Algorithm. I made sure that the class counts are balanced. i.e., an equal number of ...
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1answer
20 views

Filling created feature with values

I'm trying to improve accuracy. I created a few new features based on old features. So I need to fill new feature's empty cell with same values in order to equaling shapes.Then, I tried it with median ...
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0answers
13 views

I have transformed my cyclic variables into sin-cos variables; will I need further normalization/standardization?

I have a dataset where there are both numerical, categorical and cyclic(month-quarter) variables. I will run a regression model, but I may also use Random Forest, XGBoost etc. So I will preprocess my ...
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46 views

Sparsify meaningful data following a Gaussian distribution

Let's say I have 1-D data following a Gaussian distribution. I want to extract from this database the meaningful information, that is the information that lies far away from the mean. One way to do ...
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0answers
9 views

fit transform with mysterious special chracters

I tried to make the bag of words ...
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0answers
11 views

Preparing new samples for ML classifier with the same encoders

I was wondering what's the best way to preprocess new samples for my ML classifier. I have a raw data with about 3000 samples. I'm preprocessing it with some LabelEncoders and TargetEncdoders for ...
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0answers
25 views

Does feature normalization improve performance of Hidden Markov Models?

For training a Hidden Markov Model (HMM) on a multivariate, continuous time series, is it preferable to scale the data somehow? Some pre-processing steps may be: Normalize to 0-mean and unit-variance ...
1
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1answer
22 views

Input Normalization for Transfer Learning

If I am training a deep neural net with input features that are physical in nature (e.g. temperature, precipitation, etc), and I want to be able to perform some kind of transfer learning where I train ...
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0answers
50 views

Data normalization of count data for neural networks

I have a sparse matrix of count data that I'm using as input to a neural network. I know, usually, the input data should be normalized (e.g. via min-max scaling, $z$-score standardization, etc.). But ...
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0answers
276 views

One hot encoding as input to recurrent neural networks

I'm trying to predict next label in a pattern based on previous labels using recurrent neural network. In total I have 100 labels Example of input pattern: ...
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0answers
21 views

How can I transform (pre-process) pure count data for PCA analysis?

If 12 covariates of data are all count data (looks like a Poisson dist with the highest peak at 0), what are reasonable pre-processing methods that might make PCA more effective?
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1answer
35 views

Is there any NLP library or package which can help in adding coma, punctuations, new line appropriately in text?

I have movie transcript, where no coma, punctuations or new line. Is there any NLP technique which can help to implement this?
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0answers
16 views

Group data without losing information

Context Imagine that I have a dataset about sending messages. Each row as user_id, a batch_id, a ...
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0answers
49 views

Dummy variables for unseen data in R

I got the following problem: When I trained my model I created my dummy variables(before train-test split) in the following way: ...
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0answers
174 views

Decision Tree - Preprocessing for very sparse features

How do we pre-process data for very sparse features for a decision tree? From this Turi documentation for decision trees It mentioned this: Why chose decision trees? Different kinds of models ...
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0answers
71 views

Image preprocessing: How to resize / align / cut images of various sizes?

I want to create a new dataset for image recognition. If I have Object A that I want to recognize in images, and multiple images of various different sizes, how do I preprocess them so that they ...
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0answers
157 views

Should I remove the trend from timeseries when using DeepAR

I saw that for some other algorithms for timeseries data it is advised to remove trend and seasonality before doing the prediction (ex: ARIMA and LSTM) I figured out from the paper that SageMaker's ...
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0answers
37 views

Construction Adjacency matrix for GNN

A bit of a novice question, my data comes in the form of 2D hit points, my goal is to perform node/edge classification to find out whether this graph is my signal or background. My question is, when ...
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2answers
67 views

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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0answers
23 views

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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0answers
94 views

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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0answers
69 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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0answers
179 views

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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3answers
85 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 ...
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0answers
51 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/...
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0answers
78 views

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
146 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
78 views

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
34 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
86 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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0answers
23 views

Variable TimeStep in Spatio Temporal 3DConvNet

I'm working on a new project on climate data. I suppose my output $Y(H*W*1)$ is a consequence of a given data scenario $X(C=4*T*H*W)$ and an initial state $Y0(H*W*1)$. I've chosen a temporal ...
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0answers
24 views

Are annotated audio datasets augmented with mutated versions the way image datasets are?

Data augmentation is very standard for annotated image datasets for tasks like image labelling. Images are flipped, rotated, pixelated and so on, to add more training data and make the system robust ...
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0answers
114 views

Chunker/shallow parser for spoken language

I'm trying to extract NPs from transcribed spoken text, such as um it's the bl- it's the blue one in the right no left hand corner which contains e.g. fillers (e.g. um) and disfluencies (e.g. bl-,...
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0answers
156 views

how is countvectorizer used in real production environment?

how is countvectorizer used in real production environment? do you keep training the model with new features/vocabulary everyday and save the vocab into a flat file and reload them up on the next day?...
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0answers
91 views

Transformation of Dependent and Independent Variables

I have a few Independent variables that's normal and a Dependent variables that's skewed , I pick log(feature+SHIFT) to correct skewness. The procedure I follow to get prediction is just take exp(...
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0answers
457 views

Clustering bitcoin addresses with k-means - how would one prepare input

I am looking to perform clustering on bitcoin addresses within the blockchain. I have generated a graph structure of the blockchain with a source address, destination address, value of transaction, in-...
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0answers
51 views

How do I convert a series of timestamps in seconds to milliseconds in order to distribute them smoothly

I have a script that collects memory usage data from a device running a Linux stack. I collect samples roughly every 200ms and write the measurement to a csv file with a timestamp. The problem is ...
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0answers
320 views

How to best represent rate or proportion as a feature?

Given two features in a data set: NFObs (Number of failed observations) and NObs (Number of total observations), I'd like to ...
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1answer
386 views

What metrics must i use in my data(unstructured) preprocessing research?

i am currently working on preprocessing unstructured data (emails,logs,bug reports and irc chats). i wish to prove preprocessing improves the content quality. are there metrics available to prove ...