Machine Learning Engineer

Ratan Singh

I build production ML systems — from real-time inference at Apple Sports to LLM reasoning pipelines (GRPO, SFT, tool-use RL) and high-throughput risk engines at Credit Suisse. 10+ years shipping ML across fintech and big tech.

Experience

Career progression across fintech and big tech

Apple Inc.

May 2022 — Present

Machine Learning Engineer IV

Leading ML infrastructure initiatives for Apple platforms. Large-scale model training, optimization, and on-device inference. NDA-bound work.

Python PyTorch Transformers Core ML

Machine Learning Engineer III

Researching and deploying ML pipelines for Apple platforms. Large-scale model training, optimization, and on-device inference. NDA-bound work.

Python PyTorch Transformers Core ML

Machine Learning Intern

Prototyped NLG architectures and text processing utilities for on-device intelligence features.

Python PyTorch NLG

Credit Suisse AG

2011 — 2022

Exempt Non Officer III — ML Engineer

Redesigned multithreaded Credit Risk Calculation Engine for Wrong Way Risk trades. Built secure API server with Kafka/Hazelcast cluster monitoring and failure detection. Created Issuer Linking methodology improving counterparty data quality.

Python Java Spring Boot Kafka Hazelcast Bash

Exempt Non Officer II — ML Engineer

Designed quantitative model benchmarking credit risk (loans vs bonds). Implemented WWR Calculation Framework (FINMA/PRA compliant). Developed RWA simulation services for stress testing counterparty portfolios.

Python Keras Scikit-Learn BERT ElMo ElasticSearch

Analyst II — ML Engineer

Built SMEBot — credit risk chat assistant using NLP/DL. Intent classification with Word2Vec, GloVe, BERT ensembles. QANet for extractive QA from financial PDFs. Used by 200+ analysts.

Python Keras NLTK Deep Learning Word2Vec GloVe

Analyst I — Software Developer

Co-developed Digital Regulatory Reporting (DRR) framework accepted by FCA (UK). Automated SQL generation and testing databases for Wealth Management.

.NET Python SQL

Education & Research

Academic foundation and research experience

M.S. Electrical & Computer Engineering

Georgia Institute of Technology

2021 — 2022

  • Statistical Machine Learning
  • Computational Data Analytics
  • Random Processes
  • Digital Image Processing
  • Mathematical Machine Learning

B.Tech. Electronics & Telecomm. Engineering

Veermata Jijabai Technological Institute (VJTI)

2013 — 2017

  • Signals & Systems
  • Discrete Signal Processing
  • Linear Algebra
  • Complex Analysis

Graduate Researcher

Emory University — Clifford Lab, Biomedical Informatics

2021 — 2022

Designed and deployed audio signal processing applications using React, Python, and shell automation for biomedical data analysis. Published work on indoor localization using sparse camera networks and BLE trilateration.

Undergraduate Research Assistant

VJTI — Center of Excellence in Nonlinear Dynamical Systems

2015 — 2017

Researched convex optimization algorithms for degaussing systems using MATLAB and OPERA electromagnetics software. Published 4 papers on hexagonal coil systems for naval demagnetization.

Portfolio

Selected ML, LLM & agent projects

🧠

Mini Reasoner — Reasoning Model Training (SFT + GRPO)

Reproduced DeepSeek-R1 reasoning pipeline on Qwen2.5-3B-Instruct. Three-stage training: distilled SFT → GRPO with verifiable rewards → rejection sampling. Ablation study across GSM8K (42% → 59%), MATH, and reasoning benchmarks. Full training infra with Ray Train, vLLM, TRL.

Personal
PyTorch GRPO TRL vLLM Ray Train W&B
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Retrieval Agent — Self-Taught Tool Use (GRPO)

Trained Qwen2.5-3B-Instruct to learn its own retrieval policy via self-play rollouts with rejection sampling + GRPO optimization. Agent decides when to search, what to query, when to stop. HotpotQA F1: 31% → 47%, retrieval calls reduced 4.2 → 2.8/question.

Personal
PyTorch GRPO Tool-Use RL HotpotQA Rejection Sampling
⚙️

Coding Agent Harness — Multi-Agent Dev Environment

Built a local-first coding agent harness with sandboxed execution, file system tools, test running, and git integration. Implements planning→coding→verification loop with multi-agent orchestration (planner, coder, reviewer). Supports LangGraph/LangChain, evaluates on SWE-bench, HumanEval.

Personal
LangGraph Docker FastAPI SWE-bench Python
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LLM Evaluation & Red-Teaming Framework

Automated evaluation suite for instruction-following, hallucination detection, and safety. Implements LLM-as-judge, self-consistency checks, and adversarial prompt generation. CI/CD integration for regression testing model updates.

Personal
Python Pytest LangSmith Prometheus Grafana

Contact

Let's build something together