ESANN2019

Updated Repo TheRensselaerIDEA/synthetic_data

Supplemental Material for the ESANN 2019 Submission "Preserving privacy using synthetic data models and applications in health informatics education". This includes a supplemental section to the paper located at supplemental_material.pdf. There is also code for all of the generative methods and metrics.

Generative Methods Code

Gaussian Multivariate

The code for this method is located in the generators/gaussian_multivariate.py file. It uses the sci-kit learn Gaussian mixture method.

HealthGAN (WGAN)

The code for this method is located in the generators/wgan.py file. This method uses tensorflow to create the GAN. It is based on the methods from the paper "Improved Training of Wasserstein GANs" and the repository from the author https://github.com/igul222/improved_wgan_training.

Architecture

The architecture of the HealthGAN is as follows

• Generator
  • Input: 100 nodes of noise from the latent space of a normal distribution
  • Dense Layer of 2 x number of features in the data nodes
    • Rectified linear unit activation
  • Dense Layer of 1.5 x number of features in the data nodes
    • Rectified linear unit activation
  • Dense Layer of number of features of the data nodes
    • Sigmoid activation
• Discriminator
  • Input: number of features in the data
  • Dense Layer of 64 nodes
    • Leaky rectified linear unit activation
  • Dense Layer of 128 nodes
    • Leaky rectified linear unit activation
  • Dense Layer of 256 nodes
    • Leaky rectified linear unit activation
  • Dense Layer of 1 node
    • No activation function
• Batch size is computed to be the size of the training data divided by the number of critic iterations

Additive Noise Model

The code for this method is located in the generators/additive_noise_model.py file. It uses the random forest classifiers from sci-kit learn.

Parzen Windows

The code for this method is located in the generators/parzen_windows.py file. It uses the kernel density method from sci-kit learn.

Copy Original Data

This method just copies the original data and therefore there isn't any code included.

Privacy-preserving Data Obfuscation

This method was done using the open source software ARX.

Synthetic Data Vault Converter

The generators/sdv_converter.py file contains code to convert the data into values from 0 to 1 as described in the supplemental material. This is used for the Wasserstein GAN method to ensure the values generated are reasonable.

Metrics

Adversarial Accuracy

The nearest neighbor adversarial accuracy is calculated using the metrics/nn_adversarial_accuracy.py file.

Utility

The nearest neighbor utility is calculated using the metrics/nn_utility.py file.