Rafael Medina

Machine Learning

Talent

ColumbiaMember since June 11, 2026

Technical supportBilingualPrompt engineeringAIEnglishTelecommunicationITSpanishResearchCustomer service

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Technical supportBilingualPrompt engineeringAIEnglish

About

As an AI Trainer with Handshake AI Fellowship, I specialized in developing and evaluating domain-specific prompts to assess the performance of large language models (LLMs) in [your domain]. My responsibilities included analyzing LLM outputs for scientific accuracy, clarity, and depth in specialized subfields, contributing to the improvement of AI understanding in complex topics through expert review and feedback, and conducting independent research to support prompt development and evaluation tasks. This role allowed me to leverage my expertise in machine learning, while collaborating on impactful AI projects in a remote, contract-based capacity.

Experience

AI Trainer - Handshake AI - Remote

(2026-03)

Digital Annotation Expert - Mercor Intelligence - New York, NY

(2025-11)

Performed daily preference ranking of hundreds of multimodal AI outputs (images, audio and video) against prompts to evaluate model performance alignment.
Maintained high accuracy and throughput in large-scale annotation workflows, contributing to reliable training data for model fin-tuning and preference optimization.
Developed training data for large language models by formulating coding problems that models could not resolve, and subsequently documenting the correct solutions.
Maintained high accuracy and throughput in large-scale annotation workflows, contributing to reliable training data for AI model fine-tuning.

Bilingual Customer Service Representative - Medical Answering Services (MAS), LLC - Remote

Provide superior customer service by professionally and courteously managing a high volume of inbound calls to schedule and coordinate non-emergency medical transportation.
Resolve complex issues by effectively de-escalating and addressing advanced inquiries or complaints from clients and providers.
Maintain strict adherence to regulations by ensuring all transportation requests and procedures are in full compliance with state and federal Medicaid guidelines.
Facilitate communication with Spanish-speaking clients and providers by utilizing bilingual skills to accurately and efficiently process requests

Bilingual Disaster Assistance - FEMA / KATMAI Government Services - Remote

(2022-09 - 2023-01)

Assisted disaster survivors in the aftermath of a presidential emergency declaration, utilizing important terminology and processes to provide the best possible support.

Customer Service Bilingual Representative - Sutherland Global Services - Remote

(2016-06 - 2017-08)

Bilingual (English and Spanish) Telecommunications Support Specialist

Handled inbound calls to provide comprehensive telecommunications support to a diverse customer base.
Assisted customers by clarifying product and service options and determining their eligibility for upgrades.
Resolved customer inquiries efficiently while working from a remote home office.