Jose Javier
Gonzalez Ortiz
Telecommunications Engineer

About Me

Hi! I'm Jose Javier. I am a PhD student in Computer Science at MIT. My specialization is Machine Learning and I work at the CSAIL lab in John Guttag's research group. My main interests lie in automatic feature extraction in weakly labeled image and time series data.

I received my Bachelor's Degree in Telematics Engineering from the Universidad Pontificia Comillas ICAI. I spent my senior year in an exchange program in Computer Science at the University of Michigan, Ann Arbor.

My research interests include Machine Learning, Deep Learning, Computer Vision, Optimization and Algorithms. I am very interested in automating non-trivial tasks I also enjoy working with microprocessors and embedded devices to automate things and make life simpler.

On my spare time I enjoy reading, writing about math and code, watching MOOCs, tinkering with electronics and solving all kinds of geometric puzzles.

Experience

I've done research and internships to get a better feel for what fields I am interested in. Here's a quick summary of what I've done, as well as a link to my resume:

CERN Openlab

Summer Student

I worked in the GeneROOT project in collaboration with King's College bioinformatics. I developed C++ software to store and access Sequence Aligment/Map Data using CERN's ROOT Framework for High Energy Physics. I benchmarked the tools using Python, using statistical analysis to improve read speed by over 15 times.

University of Michigan CSE

Research Assistant

As a member of the Machine Learning for Data Driven Decisions Laboratory I developed a Heart Sound Classification algorithm based on Temporal Alignment Techniques and MFCC, achieving a 82.4% accuracy in the hidden data. I presented my work at Computing in Cardiology 2016.

Universidad Pontificia Comillas

Research Assistant

Using Android and the Google Glass prototype, I designed a QR-Based system for people with different disabilities. The application uses Google Glass as a platform to interact with a number of interfaces and it is now being used by children with special needs at a Spanish institution.

Extreme Networks

Software Engineer

As a Serive Architecture Development member, I worked with the integration of several third-party modules to the NetSight network monitor. I was responsible for producing software filters for the Paloalto Firewall, reducing unwanted requests by 68%

Publications

Learning from Few Subjects with Large Amounts of Ambulatory Data
There is increasing interest in using machine learning to build classifiers using health related time series data. However, such data often involves a limited set of subjects and long monitoring periods. Fine grained supervision is usually not available in this scenario, and soft per-subject labels are usually used. To prevent overfitting to subject-identifying features, expert-driven knowledge of the task is often used. We present a two-step classification approach that is able to generalize under these circumstances without making any assumptions about the task. We first obtain low dimensional embeddings by training a convolutional autoencoder on frequency-domain representations of the data. We then use the learned embeddings along with soft labels for the classification. We demonstrate the effectiveness of our approach on a large ambulatory voice monitoring dataset where we predict which subjects have vocal adducted hyperfunction. Our proposed method is able to generalize to unseen subjects and matches state-of-the-art results that leverage significant domain knowledge.
Jose Javier Gonzalez Ortiz, John Guttag, Robert Hillman, Daryush Mehta, Jarrad Van Stan and Marzyeh Ghassemi
NIPS 2018 ML4H: Machine Learning for Health Workshop
Heart Sound Classification based on Temporal Alignment Techniques
The 2016 PhysioNet/CinC Challenge aims to encourage the development of algorithms to classify heart sound recordings collected from a variety of clinical or nonclinical (such as in-home visits) environments. We use DTW (Dynamic Time Warping) to compare heart sounds within and across subjects. These DTW based features, coupled with widely used spectral MFCC coefficients, serve as input to a linear SVM. Applied to the held-out test set our classifier obtained a test score of 82.4%, suggesting that temporal alignment techniques can effectively reduce the effects of inter-patient variability and mitigate the differences introduced by heterogeneous data collection environments.
Jose Javier Gonzalez, Cheng Perng Phoo, Jenna Wiens
Computing in Cardiology 2016
A Simple Power Attack in the TwoFish Key Schedule
This paper introduces an SPA power attack on the 8-bit implementation of the Twofish block cipher. The attack is able to unequivocally recover the secret key even under substantial amounts of error. An initial algorithm is described using exhaustive search on error free data. An error resistant algorithm is later described. It employs several threshold preprocessing stages followed by a combined approach of least mean squares and an optimized Hamming mask search. Further analysis of 32 and 64-bit Twofish implementations reveals that they are similarly vulnerable to the described SPA attack.
Jose Javier Gonzalez Ortiz, Kevin J. Compton
arXiv 2016

Portfolio

This are some of the projects I have worked on either as class projects or in my spare time. Check them out!

dtwpy Python Package

LaTeX template for a Research Diary

LED Cube 8x8x8

Includes Snake 3D

Line Following Robot

Parallel Implementation of Multiple Interdependent Lindenmayer Systems

Binary Diagnostic Classification of Prevalent Cardiovascular Diseases

Contact

Feel free to contact me in your preferred way