---
title: "Cheon Sejun (@elioscode) | Hashnode"
description: "Be simple, Work smart. Read the latest articles by Cheon Sejun on Hashnode."
url: "https://hashnode.com/@elioscode"
---

@elioscode

# Cheon Sejun

@elioscode · Joined June 2025

Be simple, Work smart

### [Building a High-Precision Travel Guide: Optimizing RAG for a Jeju Island AI Chatbot](https://eliosdevlog.hashnode.dev/building-a-high-precision-travel-guide-optimizing-rag-for-a-jeju-island-ai-chatbot?utm_source=hashnode&utm_medium=feed)

Introduction: The Limits of Vanilla LLMs When building a tourism assistant for a specific location like Jeju Island, generic LLMs often fall short. They might hallucinate trail names, provide outdated

3 min read · [eliosdevlog.hashnode.dev](https://eliosdevlog.hashnode.dev/building-a-high-precision-travel-guide-optimizing-rag-for-a-jeju-island-ai-chatbot?utm_source=hashnode&utm_medium=feed)

[Apr 11](https://hashnode.com/posts/building-a-high-precision-travel-guide-optimizing-rag-for-a-jeju-island-ai-chatbot/69db5c38aadf1107e2ade2e4)

### [Cracking the Recycling VQA Challenge: From Baseline (0.70) to 0.901 with Qwen2.5-VL](https://eliosdevlog.hashnode.dev/cracking-the-recycling-vqa-challenge-from-baseline-0-70-to-0-901-with-qwen2-5-vl?utm_source=hashnode&utm_medium=feed)

Introduction: The VQA Frontier in Recycling In the SSAFY AI Challenge, I was tasked with a complex Visual Question Answering (VQA) problem: building a model that can look at images of recyclable waste

3 min read · [eliosdevlog.hashnode.dev](https://eliosdevlog.hashnode.dev/cracking-the-recycling-vqa-challenge-from-baseline-0-70-to-0-901-with-qwen2-5-vl?utm_source=hashnode&utm_medium=feed)

[Apr 4](https://hashnode.com/posts/cracking-the-recycling-vqa-challenge-from-baseline-0-70-to-0-901-with-qwen2-5-vl/69db5978aadf1107e2ac17ef)

### [Understanding Python Classes: A Beginner's Guide to Object-Oriented Programming](https://eliosdevlog.hashnode.dev/understanding-python-classes-a-beginners-guide-to-object-oriented-programming?utm_source=hashnode&utm_medium=feed)

Learn the basics of Python classes, object-oriented programming, and more with this beginner's guide, featuring practical examples and key concepts

7 min read · [eliosdevlog.hashnode.dev](https://eliosdevlog.hashnode.dev/understanding-python-classes-a-beginners-guide-to-object-oriented-programming?utm_source=hashnode&utm_medium=feed)

[Jun 11, 2025](https://hashnode.com/posts/understanding-python-classes-a-beginners-guide-to-object-oriented-programming/68498415b7bfea3541c012b9)

### [파이썬 초보 탈출을 위한 클래스(Class) 핵심 가이드 (feat. 던더 메서드, 상속)](https://eliosdevlog.hashnode.dev/class-feat?utm_source=hashnode&utm_medium=feed)

파이썬의 클래스, 던더 메서드, 상속 등 객체지향 프로그래밍 기초 가이드를 통해 초보 탈출에 도전하세요

5 min read · [eliosdevlog.hashnode.dev](https://eliosdevlog.hashnode.dev/class-feat?utm_source=hashnode&utm_medium=feed)

[Jun 11, 2025](https://hashnode.com/posts/class-feat/684980417ba18ec4a4c04744)

### [Mastering Python List Structures: A Detailed Look at Features and Operations](https://eliosdevlog.hashnode.dev/mastering-python-list-structures-a-detailed-look-at-features-and-operations?utm_source=hashnode&utm_medium=feed)

Explore in-depth Python list features, key methods, memory management, and dunder methods for efficient and predictable coding

8 min read · [eliosdevlog.hashnode.dev](https://eliosdevlog.hashnode.dev/mastering-python-list-structures-a-detailed-look-at-features-and-operations?utm_source=hashnode&utm_medium=feed)

[Jun 10, 2025](https://hashnode.com/posts/mastering-python-list-structures-a-detailed-look-at-features-and-operations/684844b1b54345eff5edb859)