Data Science Stack Exchange
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1500 questions
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1 answer

What do "compile", "fit", and "predict" do in Keras sequential models?

I am a little confused between these two parts of Keras sequential models functions. May someone explains what is exactly the job of each one? I mean compile doing forward pass and calculating cost function then pass it through fit to do backward…
user3486308
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How Do I Learn Neural Networks?

I'm a freshman undergraduate student (mentioning this so you may forgive my unfamiliarity) who is currently doing research using neural networks. I've coded a three-node neural network (that works) based on my professor's guidance. However, I'd like…
Furkan Toprak
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7 answers

How can I predict traffic based on previous time series data?

If I have a retail store and have a way to measure how many people enter my store every minute, and timestamp that data, how can I predict future foot traffic? I have looked into machine learning algorithms, but I'm not sure which one to use. In…
user1132959
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3 answers

How to scale up algorithm development?

In working on exploratory data analysis, and developing algorithms, I find that most of my time is spent in a cycle of visualize, write some code, run on small dataset, repeat. The data I have tends to be computer vision/sensor fusion type stuff,…
Alex I
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4 answers

Train, test split of unbalanced dataset classification

I have a model that does binary classification. My dataset is highly unbalanced, so I thought that I should balance it by undersampling before I train the model. So balance the dataset and then split it randomly. Is this the right way ? or should…
lads
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3 answers

Image resizing and padding for CNN

I want to train a CNN for image recognition. Images for training have not fixed size. I want the input size for the CNN to be 50x100 (height x width), for example. When I resize some small sized images (for example 32x32) to input size, the content…
Odgiiv
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1 answer

What does it mean to "share parameters between features and classes"

When reading this paper there is a line which says "linear classifiers do not share parameters among features and classes." What is the meaning of this statement? Does it mean that linear classifiers such as logistic regression need features…
joydeep bhattacharjee
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5 answers

Feature selection vs Feature extraction. Which to use when?

Feature extraction and feature selection essentially reduce the dimensionality of the data, but feature extraction also makes the data more separable, if I am right. Which technique would be preferred over the other and when? I was thinking,…
Sid
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4 answers

How to maximize recall?

I'm a little bit new to machine learning. I am using a neural network to classify images. There are two possible classes. I am using a Sigmoid activation at the last layer so the scores of images are between 0 to 1. I expected the scores to be…
Louis
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3 answers

What is LSTM, BiLSTM and when to use them?

I am very new to Deep learning and I am particularly interested in knowing what are LSTM and BiLSTM and when to use them (major application areas). Why are LSTM and BILSTM more popular than RNN? Can we use these deep learning architectures in…
Volka
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4 answers

Train/Test Split after performing SMOTE

I am dealing with a highly unbalanced dataset so I used SMOTE to resample it. After SMOTE resampling, I split the resampled dataset into training/test sets using the training set to build a model and the test set to evaluate it. However, I am…
Edamame
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6 answers

Tool to label images for classification

Can anyone recommend a tool to quickly label several hundred images as an input for classification? I have ~500 microscopy images of cells. I would like to assign categories such as 'healthy', 'dead', 'sick' manually for a training set and save…
jlarsch
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3 answers

How to get predictions with predict_generator on streaming test data in Keras?

In the Keras blog on training convnets from scratch, the code shows only the network running on training and validation data. What about test data? Is the validation data the same as test data (I think not). If there was a separate test folder on…
pseudomonas
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3 answers

How to calculate the mini-batch memory impact when training deep learning models?

I'm trying to calculate the amount of memory needed by a GPU to train my model based on this notes from Andrej Karphaty. My network has 532,752 activations and 19,072,984 parameters (weights and biases). These are all 32 bit floats values, so each…
barbolo
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4 answers

How to initialize a new word2vec model with pre-trained model weights?

I am using Gensim Library in python for using and training word2vector model. Recently, I was looking at initializing my model weights with some pre-trained word2vec model such as (GoogleNewDataset pretrained model). I have been struggling with it…
Nomiluks
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