About me

  • Name: Jiyong Youn (윤지용)
  • Nickname: HLETRD
  • Contacts
  • Language
    • Korean (Native)
    • English (Fluent)
  • Works
      • Developer, Puzzle Monsters Inc. (2024. 04. -)
      • 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 DesignerEasyEDA 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

VMO lab intranet (https://vmo.snu.ac.kr) (2021)

  • Intranet website based on Python 3, Django

Spectools (https://github.com/hletrd/spectools) (2017)

  • Spectral analysis tools for astronomy, based on Python and AstroPy.

JubeatInfo Festo (https://jubeatinfo.com) (2018-)

  • Website providing personalized stats & records of Jubeat Festo.
  • Based on Python 2, Flask, MongoDB
  • 500+ active users

JubeatInfo Clan (http://c.jubeatinfo.com) (2017-2018)

  • Website providing personalized stats & records of Jubeat Clan.
  • Based on Python 2, Flask, MongoDB
  • 300+ active users

QubellInfo (http://q.jubeatinfo.com) (2016-2017)

  • Website providing personalized stats & records of Jubeat Qubell.
  • Based on Python 2, Flask, MongoDB
  • 1000+ active users

Acrux (https://github.com/hletrd/Acrux) (2017)

PyPreprocessor (https://github.com/hletrd/PyPreprocessor) (2017)

  • Based on Python 3, Astropy, Numpy,
  • Various scripts for processing observational data for astrophotography as well as astrophotometry.

Neural Style Online (https://github.com/hletrd/neural_style) (2015-2016)

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-)

STM32 Pro Mini dev board (https://github.com/hletrd/STM32ProMini) (2020-)


Golang (2021-)

Ethereum benchmarking environment (https://github.com/hletrd/go-ethereum-sim) (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-)

SAO Weather Monitor (2018-)

  • Automated weather monitor for SNU Astronomical Observatory

XpressEngine contributor (2016)

DDR Info (https://github.com/hletrd/DDR-Info) (2015)

  • Website provides personalized stats & records of Dance Dance Revolution.
  • 200+ users
  • Based on PHP, MySQL

YOTTA (https://github.com/hletrd/YOTTA) (2015)

  • Fully encrypted file storage.
  • Based on PHP, MySQL

River temperature API Link to API documentation (2015)

  • API providing water temperature of rivers in Korea.

RFLP Designer Demo


Java/Kotlin/Android (2014-)

  • Swing / AWT

TabletDroid (Link to Play store) (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-)

Ethereum analyzer https://github.com/eth4ne/eth-analysis (2022)

  • DB dump & analysis tool for Ethereum blockchain

Voice identification demo https://lgcns.xylolabs.com (2021)

  • Voice identification tool to verify an user via reading a short phrase
  • Developed front-end, using React.

    Awkward billiard (Experimental) (https://0101010101.com/labs/billiard/) (2015)

    • Based on HTML5 + Javascript
    • Awkward…

    Simple word test (https://0101010101.com/labs/wordtest) (2013-2015)

    • Simple tool to memorize words fastly

    TT4Them https://hletrd.github.io/TypingTutor4Them/ (2016)

    • IME-independant typing tutor application, running in browser.
    • Source code

    HangangSwim (Link to Pebble App Store) (2016)

    • 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

    Git hash miner (https://github.com/hletrd/gitminer-cuda) (2021)

    • To practice CUDA…
    • Found a lowest SHA1 hash (probably): 00000000000000c06d2e8c36f247206a9a4b1c63

    GPUPhotometry (https://github.com/hletrd/GPUPhotometry) (2015)

    • Based on C + OpenCL + GTK+ + CFITSIO
    • Very fast CCD data reduction with GPU computing

    MD5 maxmin solver (https://github.com/hletrd/md5-maxmin) (2015)

    • 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.