João Assaoka
Generative AI Engineer & CS PhD Researcher

João Assaoka

João Victor Assaoka Ribeiro

Generative AI Engineer & CS PhD Researcher

Generative AI Engineer and CS PhD researcher at UNIFESP. I investigate methodologies for efficient post-training and real-world LLM operationalization.

Keywords: Python, IA, Deep Learning, Agentes, LLM, RAG, Hugging Face, LangChain, vLLM, Streamlit, Claude Code, Antigravity

Languages: Portuguese (Native), English (Advanced)

Education

PhD in Computer Science

Mar 2024 – Present
Federal University of São Paulo (UNIFESP)
GPA: A
  • Regular Direct PhD Student (Jan 2027 – Dec 2030): Invited to enter directly into the PhD program in recognition of academic performance and scientific production during undergraduate studies.
  • Special Graduate Student (Mar 2024 – Present): Completed graduate courses concurrently with undergraduate studies, earning the maximum grade (A) in all: Algorithm Analysis and Data Structures, Artificial Intelligence, Neural Networks, Operations Research, and Seminars.

Visiting International Research Student

May 2026 – Aug 2026
Dalhousie University
Halifax, Canada
  • Member researcher of the DNLP Group and Malanis Lab, participating in discussions and experiments on the state of the art in Natural Language Processing (NLP) and Machine Learning.

Bachelor of Science in Computer Science

Feb 2026 – Present
Federal University of São Paulo (UNIFESP)
GPA: 9.25/10
  • Ranked 3rd place in the career progression selection process following the interdisciplinary cycle.
  • Relevant Coursework: Calculus, Linear Algebra, Linear Optimization, Operations Research, Problem Solving via Mathematical Modeling, Topics in Economics and Business, Algorithms and Data Structures, Object-Oriented Programming, Software Engineering, Databases, Probability and Statistics, Inference and Regression Analysis, Machine Learning, Artificial Intelligence, and Neural Networks.

Bachelor of Science in Interdisciplinary Science and Technology

Mar 2023 – Feb 2026
Federal University of São Paulo (UNIFESP)
GPA: 9.23/10
  • Certificate of Emphasis in Data Science Fundamentals.
  • Academic Teaching Assistant: Served as TA for Programming Logic and Algorithms & Data Structures courses.

Experience

Natural Language Processing Researcher

Nov 2024 – Present
PARANA Research Group | FAPESP | Serasa Experian
Remote
  • Increased correlation with human judgment by 113% (from 0.23 to 0.49) in reference-free financial news summarization evaluation, proposing and implementing task decomposition via Question Answering with LLMs in Python and LangChain.
  • Accelerated multi-task retraining cycle by 99.5% (from 1h17min to 25s) while preserving 94.7% of Macro-F1, by architecting an SLM Model Merging strategy via Mergekit.
  • Increased relative Macro-F1 by 31.2% in multi-class toxicity detection under imbalanced scenarios by structuring synthetic data augmentation pipelines via LLMs.
  • Built a proprietary financial domain dataset (5,000+ samples), developing scraping with Selenium, a web annotation platform in Streamlit, relational modeling in PostgreSQL (Neon/SQLAlchemy), and exploratory analysis with Pandas and Matplotlib.
  • Architected fine-tuning pipelines (Full, LoRA, IA3, Soft Prompts via Hugging Face) and inference (vLLM) with structured outputs, orchestrating experiments across multi-GPU NVIDIA nodes in an HPC Linux environment (Digital Research Alliance of Canada) via Slurm.

Data and AI Department Manager

Dec 2024 – Jan 2026
SciTec Jr.
Remote
  • Founded and structured the consultancy's dedicated Data Science and Artificial Intelligence department, leading the spin-off from the computing division and establishing new hiring criteria that enabled talent attraction across multiple engineering fields.
  • Managed the lifecycle and technical delivery of 6 projects, encompassing 3 consulting initiatives for external clients and 3 internal operational automation products focused on process scalability.
  • Upskilled new consultants in Data and AI competencies, designing the technical learning track and conducting training sessions in Python, exploratory data analysis (Pandas, Matplotlib), CRISP-DM methodology, interactive Streamlit interfaces, and LLM orchestration with LangChain.

Generative AI Engineer

Feb 2025 – Jul 2025
Ativamente - Enactus UNIFESP São José dos Campos
Remote
  • Reduced clinical report generation time by over 90% (from 1–3 hours to 5 minutes) by architecting an integrated data solution with a Streamlit interface and an automated LLM summarization pipeline.
  • Developed an intelligent conversational agent (Text-to-SQL / Chatbot) capable of interpreting natural language queries and extracting on-demand analytical metrics from cognitive workshop data and elderly participant medical records.
  • Centralized and standardized the workshop data ecosystem, replacing fragmented legacy spreadsheets with a structured relational architecture and input forms.

Prescriptive Maintenance & XAI Researcher

Jul 2023 – Dec 2024
PARANA Research Group | FAPESP | IAsmin Platform | Siemens Energy
Remote
  • Enabled operational cost savings and proactive industrial failure prevention by predicting sensor time-series degradation signals, developing and benchmarking models ranging from linear baselines (Linear Regression) to gradient-boosted ensembles (XGBoost) and deep recurrent architectures (LSTM).
  • Implemented a multi-technique Explainable Artificial Intelligence (XAI) framework using SHAP, ALE (Accumulated Local Effects) plots, and partial dependence (PDP 1D/2D), diagnosing complex causal interactions to validate prediction alignment with domain engineering knowledge and increase decision-making transparency.
  • Co-created the IAsmin educational platform, democratizing practical XAI and Industry 4.0 predictive maintenance methodologies in Portuguese through 7 hands-on tutorials detailing theoretical foundations and interpretability implementations.

Selected Publications

All 6 Publications

United Experts: Efficient Multi-Task Sentiment Analysis in Portuguese via Model Merging

João Assaoka, Evangelos Milios, Vlado Keselj, José Vitor Requena, Diego Miranda, Lilian Berton

Reduced multi-task model creation time to just 0.5% of standard fine-tuning by merging specialist LLM checkpoints without performance degradation. Joint work during research visit with Dalhousie University.

ENIAC 2026 Model Merging Multi-Task Learning Resource-Efficient NLP

Evaluating Reference-Free Summarization Quality Metrics for Portuguese: A Study with Human Judgments in Financial News

João Victor Assaoka Ribeiro, Thomas Correia, José Vitor Requena, Lilian Berton

Study analyzing reference-free summarization quality metrics for financial news in Portuguese, demonstrating that question-answering decomposition outperforms monolithic LLM judges against human annotators.

PROPOR 2026 Summarization Evaluation NLP Financial News

Mitigating Imbalance in Portuguese Toxicity Classification via LLM Augmentation and Cross-Dataset Label Propagation

José Vitor Requena, João Assaoka, Lilian Berton

Investigation into data scarcity and class imbalance in toxic speech detection, evaluating LLM-based synthetic generation and cross-dataset label propagation strategies in Portuguese.

ENIAC 2026 Data Augmentation Toxicity Classification Imbalanced Learning

A Multimodal Framework for Financial Fake News Detection for Brazilian Portuguese

José Vitor Requena, João Assaoka, Lilian Berton

Multimodal architecture combining textual and visual signals for detecting financial misinformation and deceptive news in Brazilian Portuguese.

PROPOR 2026 Multimodal NLP Fake News Detection Financial Domain

Benchmarking Text Classifiers for Economic News in Brazilian Portuguese: In-Domain Quality and Out-of-Distribution Generalization

Diego Miranda, João Assaoka, Lilian Berton

Extensive benchmark of neural architectures evaluating both in-domain performance and out-of-distribution robustness across economic news corpora.

ENIAC 2026 Benchmarking Out-of-Distribution Financial NLP

Negotiating LLMs for Enhanced Hate Speech Classification and Interpretability

João Assaoka, Lilian Berton

Multi-LLM negotiation framework to improve classification precision and generate faithful rationales for toxicity detection in Portuguese.

ENIAC 2025 LLM Collaboration Explainability Toxicity Detection

Awards & Honors

Undergraduate Excellence Award

2025
Federal University of São Paulo (UNIFESP)
Winner – Technical or Technological Products Category
  • Winner in the Technical or Technological Products category for outstanding undergraduate research and scientific development.

Undergraduate Excellence Award

2026
Federal University of São Paulo (UNIFESP)
Campus Nominee – Exact Sciences Scientific Research
  • Project selected in the campus stage under the Exact Sciences Scientific Research category to represent the campus in the university-wide institutional award (pending).