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ZZ

Zhassulan Zhangbyrbay

@Savant322

AI Engineer

NLP, LLM, and ML engineer with 5+ years of end-to-end experience across multilingual text classification, retrieval systems, model fine-tuning, and production deployment.

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About

Strong background in transformer architectures, BERT-based classification, Retrieval-Augmented Generation (RAG), GraphRAG on Neo4j, and MLOps best practices. Experienced in building scalable, business-facing AI systems from data preparation and experimentation to deployment, monitoring, and iterative improvement.

Career

Experience: 5 years

Experience

ML Engineer

Sigli

Oct 2025 — Present

Fine-tuned multilingual CEFR models and built language-processing tools, pipelines, and QA tooling.

• Fine-tuned BERT-based CEFR text classification models for English, Dutch, French, and German, covering all 6 proficiency levels (A1–C2) and improving multilingual scoring consistency. • Built multilingual training and evaluation pipelines for CEFR prediction, including dataset preparation, feature extraction, error analysis, and comparative model experiments. • Developed spell-check and autocomplete components using lexicons of up to 200K entries, prefix indexing, and edit-distance candidate generation for user-facing suggestion systems.

AI Engineer

VEON

International telecommunications and digital services group.

Jan 2025 — Oct 2025

Delivered a RAG chatbot and document-search pipeline; search fallback reduced the no-answer rate by 37%.

• Built and deployed a stakeholder-facing chatbot on a new RAG stack, delivering 85% answer accuracy with a 5–10 s response time per query. • Experimented with GraphRAG on Neo4j alongside vanilla RAG, deepening team expertise in graph-augmented retrieval techniques. • Indexed ~1,000 documents (~40,000 pages) through an OCR pipeline built with pypdfium2 and marker, unlocking semantic search across previously non-digital content. • Integrated live Bing and Google search fallback, cutting the no-answer rate by 37%, and implemented MCP for end-to-end traceability and maintainable production code.

NLP Engineer

Pivotics

Nov 2023 — Jan 2025

Built a car sales timing model and improved Llama 2 inference speed and answer relevance.

• Built a neural network for car sales timing prediction, achieving a 3.8 RMSE versus a 6.5 benchmark. • Leveraged Nvidia TensorRT-LLM to accelerate Llama 2 inference (7B: 48→106 token/s; 13B: 35→59 token/s). • Applied prompt engineering to eliminate redundant queries, improving answer relevance by 40%.

Data Scientist

Kaspi.kz

Kazakhstan-based financial technology, payments, and e-commerce company.

Jan 2021 — Oct 2023

Built and optimized voice-bot models and monitoring; the bot handled nearly 5 million calls monthly.

• Deployed a high-load BERT-based microservice for an outbound voice bot that classifies client intent, replacing 700 call centre managers and handling nearly 5 million calls per month. • Ran A/B tests showing a 7 pp error reduction with BERT versus Rasa DIETClassifier. • Fine-tuned Llama 2 with PEFT to produce personalized, context-aware conversation scripts, and optimized production inference with 8-bit quantization, lru_cache, and JMeter load testing. • Implemented a CatBoost model for real-time voice bot monitoring, cutting error response times from 24 hours to 1 hour.

Education

PhD, Data Science

Satbayev University

2026

Master of Science, Data Science

Kazakh-British Technical University

2025

Bachelor of Science, Data Science

International Information Technology University

2023

Skills

PythonSQLPyTorchTensorFlowDockerLinuxGit/GitHub/GitLabCI/CDTransformers (BERT, Llama, Claude)OpenAI APICEFR ClassificationPrompt EngineeringRAGGraphRAG on Neo4jLangChainLlamaIndexHugging FaceLoRA Fine-tuningMCPMilvus