Cesar Romero
Verified Expert in Engineering
Linux Developer
Seattle, WA, United States
Toptal member since February 19, 2024
Cesar has over 13 years of experience in machine learning and software engineering. His career spans reputable industry giants like Amazon, Walmart, and Unity and smaller startup environments. Proficient in constructing large-scale classifiers and recommenders, Cesar has spearheaded initiatives involving the utilization of synthetic data for computer vision tasks. Currently freelancing, he prioritizes building maintainable systems that facilitate rapid iteration cycles.
Portfolio
Experience
- Linux - 20 years
- Machine Learning - 17 years
- Artificial Intelligence (AI) - 17 years
- Python 3 - 16 years
- Amazon Web Services (AWS) - 13 years
- Docker - 8 years
- PyTorch - 5 years
- Kubernetes - 5 years
Work Experience
Principal Machine Learning Engineer
R5
- Developed a tool to help detect near duplicate images in computer vision datasets, reducing the time to clean the dataset from days to minutes.
- Developed a tool to create datasets for different computer vision tasks and formats starting from video annotations, resulting in better benchmarks and more reproducible experiments.
- Implemented a new centralized dataset registry and process using DVC, S3, and GitLab, resulting in more visibility for management and more reproducible experiments for scientists.
- Designed and supervised the implementation of pipelines and processes for end-to-end offline experimentation, reducing the need for costly visual inspection and enabling data-informed decisions before new models were deployed to production.
- Created a plan to automate the process of producing and serving personalized recommendations, including A/B testing integration, reducing the frequency of updated recommendations from two weeks to daily.
- Created a plan to integrate novel AI behavior into a new VR game, enabling a personalized experience with an agent that can learn in real-time, interacting with the player.
Machine Learning Engineer
groundlight AI
- Worked on the project with the initial batch of full-time engineers, dealing with high ambiguity and adapting to multiple roles as needed.
- Built several aspects of the infrastructure, including monitoring and automated provisioning of edge devices.
- Redesigned and implemented critical parts of the core codebase to increase the productivity of scientists and enable more complex ML pipelines in production.
Principal Machine Learning Engineer
Unity
- Worked across teams in the AI department and led collaborations with other departments.
- Spearheaded initiatives to direct ML and Unity developers toward creating tools for generating synthetic data to enhance computer vision using Unity.
- Played a role in refining the scope of domains and tasks for the initial release of the open-source perception package.
- Identified the necessity for a new internal simulation platform that supported various workloads, including distributed reinforcement learning (RL) and automated domain randomization. This led to the formation of a dedicated simulation platform team.
- Hosted weekly AI lightning talks and reading groups focusing on computer vision, Python, and software design, with monthly Ask Me Anything (AMA) sessions. These avenues aimed to enhance transparency and foster alignment within the AI department.
- Co-authored a proposal to fund a new company-wide ML platform team using tools like Kubeflow, Katib, and MLflow.
Software Development Engineer
Amazon.com
- Automated hyperparameter optimization for recommendation models.
- Used neural networks to produce personalized recommendations across categories and devices (Github.com/amznlabs/amazon-dsstne).
- Engaged as a member of the AWS machine learning service launch team. (Console.aws.amazon.com/machinelearning/).
- Played a role in the same-day delivery launch team (Amazon.com/sameday). Automated the process of determining export eligibility using machine learning.
Linux Administrator
Universidad Simon Bolivar
- Implemented a process to provision several new Linux workstations for students, resulting in a new lab of 16 computers all installed and configured in a single afternoon.
- Performed regular backups of student and professor accounts for the computer science department.
- Implemented a script to automate the backup of individual students and professors, resulting in more free storage on servers, which enabled higher quotas for all active users.
- Installed and configured a server to host internal forums to enhance the existing email lists, resulting in new ways for professors to communicate with students.
- Installed and configured a new DNS server for a new research lab, resulting in a new subdomain that could be used for professional emails and a new website to showcase the work of the researchers at the lab.
- Designed and implemented a new site for a new research lab, enabling the staff to maintain a list of projects that showcase the work done by the researchers.
Project History
Video Stream Processors with Computer Vision
https://github.com/groundlight/stream/tree/mainUnity Simulation
I spearheaded the research endeavor focused on training a cutting-edge object detection model using 90% synthetic data.
Amazon Machine Learning
After the launch, I assumed the position of tech lead to bring containers into the service to make it easier to leverage the ecosystem outside of Amazon. That was the beginning of what was launched two years later as SageMaker.
Synthetic Data for Computer Vision
Pathogen Classification from DNA Sequences
https://github.com/romerocesar/pythogenI am the author and sole developer on this project. Several features were discussed and prioritized with my only collaborator, a researcher representing the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) and Johns Hopkins University.
Education
Master's Degree in Computer Science
UCLA - Los Angeles, CA, USA
Skills
Libraries/APIs
PyTorch, Pandas, TensorFlow, OpenAI API, REST APIs, OpenCV, D3.js, React, Node.js, Twilio API
Tools
Git, Amazon OpenSearch, NVIDIA Jetson, Fluentd, GitHub, ChatGPT, Claude Code, Emacs, Jupyter, Ansible, Google AI Platform, Unity SDK, GitLab CI/CD, Google Stackdriver, Apache Airflow, Subversion (SVN), TensorBoard, Amazon SageMaker, Claude, Biopython, Whisper, Amazon Cognito
Languages
Python 3, Python, Java, JavaScript, SQL, C#, Python 2, TypeScript, C++
Paradigms
Object-oriented Programming (OOP), Microservices, Automation, Model Context Protocol (MCP)
Platforms
Linux, Docker, Amazon Web Services (AWS), Kubernetes, Amazon EC2, YouTube, Kubeflow, NVIDIA CUDA, Google Cloud Platform (GCP), SharePoint, AWS Lambda, Twilio, Embedded Linux
Storage
Amazon S3 (AWS S3), Google Cloud, Elasticsearch, Redis, PostgreSQL, MySQL
Frameworks
Django, AngularJS, Hadoop, Bootstrap, Unity, LangGraph, Agentic Frameworks, Streamlit
Other
Machine Learning, Artificial Intelligence (AI), Computer Vision, Interviewing, Text Classification, Data Science, Predictive Modeling, Data Scientist, Logistic Regression, Statistical Modeling, Data Analytics, Data Analysis, A/B Testing, Training, Fine-tuning, Deep Learning, Neural Networks, AI Model Training, Exploratory Data Analysis, Classification, Models, Predictive Analytics, Spanish, SaaS, Architecture, API Design, API Integration, Full-stack Development, APIs, Software Architecture, System Architecture, Algorithms, MLflow, Public Speaking, Recommendation Systems, Hyperparameters, Technical Leadership, Leadership, Mentorship & Coaching, Generative Pre-trained Transformers (GPT), Machine Learning Operations (MLOps), Large Language Models (LLMs), Applied Research, NLU, Natural Language Processing (NLP), eCommerce, CI/CD Pipelines, Open Source, Open-source Software (OSS), Decentralization, Research, AI Modeling, Chief AI Officer, Prompt Engineering, LangChain, Web Development, OpenAI GPT-4 API, Convolutional Neural Networks (CNNs), Web Scraping, Education, OpenAI, AI Agents, AI Chatbots, Agentic AI, Chatbots, FastAPI, Retrieval-augmented Generation (RAG), Image Processing, Embedding Models, RAG Systems, Image Analysis, AI Integration, Workflow Automation & System Integration, Solution Architecture, Vector Databases, AI Design, AI Programming, Conversational AI, Pattern Recognition, Authentication, Authorization, Optimization, RTSP, Robotics, AI Research, GPU Computing, Data Manipulation, Big Data, Causal Inference, Language Models, Data Engineering, Image Generation, State Machines, Search Engines, DNS, Medical Imaging, Reinforcement Learning, LoRa, Hugging Face, Pinecone, Weaviate, Facial Recognition, Large Language Model Operations (LLMOps), Transformers, Data Classification, Data Visualization, Image Segmentation, RAG Architecture, Document Processing, Server-side PDF Generation, Scalable Vector Databases, AI Tools, 3D, 3D Rendering, User Interface (UI), Vehicle Routing
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