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- Name: Jiyong Youn (윤지용)
- Nickname: HLETRD
- Contacts
- Language
- Korean (Native)
- English (Fluent)
- Works
-
- Software Engineer, Application Platform, Sendbird, Inc. (2025. 01. – )
- Developer, Puzzle Monsters, Inc. (2024. 04. – 2024. 12.)
- System Engineer, Perigee Aerospace, Inc. (2023. 11. – 2024. 04.)
- CEO & Founder, Xylolabs (2022.09. – 2024.05.)
- Selected for the Entrepreneurs Support Program in Hanyang University (한양대학교 예비창업자 지원사업) in 2022
- Selected for LG CNS Startup Monster in 2021
- Research Project with Korea Forest Research Institute (국립산림과학원) in 2020
- Seoul National University X-Corps: Awarded 3rd place twice (2020, 2022) and 1st place twice (2019, 2021) as a team.
- Educations
- Ph.D. candidate in Electrical and Computer Engineering, Seoul National University (2020 -)
- Virtual Machine and Optimization Lab., Advisor: Prof Soo-Mook Moon
- B.S. in Electrical and Computer Engineering, Seoul National University (2020)
- Graduated Gyeonggi Science High School (2016)
Skills & Works
Hardwares
- From designing to manufacturing of electrical circuits, including PCB designing, and programming of embedded microcontrollers/FPGA.
- Experiences in STM32, FPGAs, ESP32, ESP8266 microcontrollers, AVRs, Arduinos, …
- PCB EDA: Prefer Altium Designer, EasyEDA as an EDA tool.
- 3D CAD/CAM: Prefer SolidWorks and Autodesk Fusion 360 for 3D product design and Autodesk AutoCAD for 2D design.
- Raspberry Pi
- Developed NanoFocus, an electronic focuser controller for astrophotography.
- Developed focusing system & filter control system for SNU CEOU 24inch telescope
- Designed and built motor controlling hardware.
- Developed ASCOM PC driver using C#, control GUI using web with Python 3 / Flask backend.
Softwares
- All projects listed below are solely developed, unless otherwise mentioned.
Python 2/3 (2015-)
- Also skilled in various frameworks. (Flask, Django, Numpy, Scipy, PyQt5, AstroPy …)
- Additional projects are available on my GitHub
- Intranet website based on Python 3, Django
- Spectral analysis tools for astronomy, based on Python and AstroPy.
- Website providing personalized stats & records of Jubeat Festo.
- Based on Python 2, Flask, MongoDB
- 500+ active users
- Website providing personalized stats & records of Jubeat Clan.
- Based on Python 2, Flask, MongoDB
- 300+ active users
- Website providing personalized stats & records of Jubeat Qubell.
- Based on Python 2, Flask, MongoDB
- 1000+ active users
- Based on Python 3, Astropy, Numpy,
- Various scripts for processing observational data for astrophotography as well as astrophotometry.
Others
- Outsources projects.
-
- TheChairs, LENIF (2018-2023)
- Developed an hardware to monitor user’s pose from chair, and developed an Android App collect the data via BLE on smartphone.
- Used Python 3, Java, C++
- SITUDY (2018)
- Developed web frontend and visualization systems for study time monitoring service
ARM Cortex M (2018-)
Golang (2021-)
- A forked Go-Ethereum client to support local replay of the entire blockchain.
C# (2017-)
NanoFocus ASCOM drivers
- Developed custom ASCOM (Astronomy Common Object Model) drivers and PC console for NanoFocus electronic focuser (which is also self-developed), enabling compatibility with the most popular astronomy softwares
- Currently installed in the SNU CEOU 24-inch telescope.
PHP5, PHP7, PHP8 (2014-)
- Automated weather monitor for SNU Astronomical Observatory
- Website provides personalized stats & records of Dance Dance Revolution.
- 200+ users
- Based on PHP, MySQL
- Fully encrypted file storage.
- Based on PHP, MySQL
- API providing water temperature of rivers in Korea.
RFLP Designer Demo
Java/Kotlin/Android (2014-)
- Make your Android phone to be used as a tablet(input device.)
- PC client is based on Visual Basic 6
- Taken down due to Google Play policy update
Javascript (2013-)
- DB dump & analysis tool for Ethereum blockchain
- Voice identification tool to verify an user via reading a short phrase
- Developed front-end, using React.
- Based on HTML5 + Javascript
- Awkward…
- Simple tool to memorize words fastly
- IME-independant typing tutor application, running in browser.
- Source code
- Based on Pebble.JS SDK
- Simple app displaying water temperature of nearest river, with KOSPI/KOSDAQ informations.
GPU computing (2015-)
- Moderately skilled in CUDA, OpenCL
- To practice CUDA…
- Found a lowest SHA1 hash (probably):
00000000000000c06d2e8c36f247206a9a4b1c63
- Based on C + OpenCL + GTK+ + CFITSIO
- Very fast CCD data reduction with GPU computing
- Based on C + OpenCL/CUDA
- Now holding records for known MD5 extreme values.
- Max:
md5(0DbB^a2hxjdc_JiyongYoun-HLETRD) = fffffffffffffec29931c5489a14a02e
- Min:
md5(08ni(g0u3ada_JiyongYoun-HLETRD) = 00000000000000d4a49581c7f0638557
- Popcount max:
md5()to0wzR*x[L{WJ^y5G>B-HLETRD) = fb9fdfff13efffffffdfffe2efeffaff
- Popcount min:
md5(hhQ1/'jy5W^G[zwJ*RBL-HLETRD) = 0000098a020401801208448010004024
- Bytesum max:
md5(wWrC--3mn-a000000000-HLETRD) = fffae5f0faf8f9f5e6f0fafbf7f8e7f6
- Bytesum min:
md5(Gs4u^x4mn{4000000000-HLETRD) = 0405041602140309020a3c071702070a
- …and a few other languages not listed above…
- C(2010-), C++(2011-), especially for OpenCL, CUDA, and embedded systems(ARM Cortex-M, AVR)
- Assembly newbie (x86, AVR, ARM Thumb/Thumb-2)
- Visual Basic(2009-)… for XP-compatible applications…
- HTML5, CSS, JS (For web dev)
Others
Had prefered CentOS/RHEL than Ubuntu
- But Ubuntu is more convenient now…
- Prefer Git as VCS.
- Prefer MariaDB along various RDBMSs.
- Prefer MongoDB and Firebase along many NoSQLs.
- Love Adobe CC products, especially Photoshop, Lightroom, Premiere, and Audition.
- Use PixInsight as post-processing tool for astrophotography.
- Participant, and gold medal winner of IBO 2014
- Feel free to contact me if you are past IBO participant.
- Use Visual Studio Code as the main text editor.