Professional Experience

Freelancer (2022-2024)

Ported legacy web application based on .NET Framework into modern Blazor and ASP.NET Core.

R&D Engineer @ Be IP (2015-2022)

Be IP. Maintained and upgraded the web-based VoIP management system which provides functionalities like user management, phone number allocation, incoming & outgoing call routes, etc. Changing configurations on the web pages propagates to Asterisk, OpenSIPs, and other softwares on the Linux server.

At the first place, it was written upon house-made PHP framework. Then, it was migrated into Symfony. After a while, it was emerged into Symfony backend + Angular frontend. The backend was RESTful API built upon Symfony, Doctrine ORM, and API-Platform. The frontend was a Single Page Application with VoIP client based on SIP and WebRTC.

Enhanced Debian Linux system with cron, systemd, and various automated configurations.

Automated installation with Python and Debian package system.

Utilized MariaDB, the open source fork of MySQL, and Redis before it was capitalized. Now, it's Valkey.

Improved ability to read and study RFT documents related SIP and HTTP.

Internship @ Ergonomic Design Technology Lab, POSTECH (2013)

Designed and developed ergonomic game utilizing early stage of Node-Webkit and Processing.js. Also, developed custom driver for Phidgets and Node.js to use specific controller to play the game.

Improved ability to implement new device out of its technical documents.

Mathmatics Teacher and Tutor (2005-2008)

Teached mathmatics for students age from 11 to 17 at a private after-shool class. The group size varied between 2 and 8. Also, tutored students in the same age group individually.

Approached to each student with different method according to their level of interest and intelligence. For example, for a very distracted 8 year old child, I let him play with jigsaw puzzle in order to improve his patience to sit on a desk for a certain amount of time and his grit to finish the problem and his geometric awareness.

Education

Bachelor of Computer Science

@ Handong Global University ( - 2014)

not finished

Master of Electronics and ICT Engineering Technology @ KU Leuven (2022)

Non-professional Experience

Member @ ICEL, Belgium (2014-)

ICEL. Played role as an accompanyment pianist. Developed webpages for the community. Became member of the board (2018 - ).

Toy Projects

Various web crawlers

with BeautifulSoup

Solved some brain teasing problems

For example, Project Euler and Exercism

Home IoT

Structured base HTTP server with Python, Flask, Docker, systemd on Raspberry PI. In the server, there is a worker that polls each sensors to get the data and store it in local. When the data is requested, it shows the latest data collected.

The sensor was built with ESP8266 board. It has WiFi. The thermometer and hygrometer sensors were soldered on the board. A simple HTTP server that provides the current value of the sensors.

The network was behind NAT. Allowing access from outside via Zero Trust Network Access

Skills

Languages

English C1 Korean C2 Dutch B1 French A1 Spansh A1

Programming Languages

PHP Python TypeScript Rust C# ECMAScript JavaScript C Bash VBA

Frameworks & Libraries

Symfony Doctrine ORM API-Platform
Angular Blazor Tailwind CSS SvelteKit
Flask Pelican

Softwares & Tools

Debian Linux Windows 11 WSL
Asterisk OpenSIPs
SQLite Redis MariaDB MySQL
Docker Desktop Git GitHub GitLab
systemd cron
Makefile Vim Bun

Hardware

Arduino Raspberry PI ESP8266 board ReMarkable HHKB

Others

piano (intermediate) melodion trumpet (beginner) reharmonization setting up sound system simple bicycle repairment Brazilian jiu-jitsu (beginner) simple music production Reason Studio Microsoft Excel Microsoft Powerpoint LibreOffice Calc InkScape GIMP