Ordinary one who questions everything in the universe (and multiverse).

Elephants all the way down (and me), Chiang Mai University Art Museum, December 2010

Born in 1989 at the dawn of the internet era, I spent my prehistoric years with (too) many mathematics books. Then I embedded myself in vcharkarn.com, the only Thai online community at the time dedicated to academic discussions (no, pantip, you’re not). Later, I switched to blognone when my interests shifted from math to com-sci, only to find out years later that the two disciplines are actually each other in disguise!

I picked the alias “เนยสด” (/nɤːjsot/, stylized in ASCII as neizod) because I couldn’t touch-type back then. So when computer games prompted me to submit a new high score, I rushed my fingers and hit Enter on the totally wrong keyboard layout without looking at the screen. I was annoyed at first, but then found it quite cool, so I adopted it with a little modification to make it readable.

To keep in touch, email me at nattawut.p (at) ku (dot) th or find @neizod on Twitter (no, I refuse to call it X).

Education

• Kasetsart University, class of 2023, Ph.D. in Computer Engineering.
  • Advisor: Jittat Fakcharoenphol
  • Thesis: Algorithm for Counting Problems in Geometry and Combinatorics (link)
• Kasetsart University, class of 2015, M.Sc. in Information Technology.
  • Advisor: Jittat Fakcharoenphol
  • Independent study: Using On-line Source Code Repositories to Analyze Technical and Social Aspects of Programming
• Chiang Mai University, class of 2013, B.Sc. in Mathematics and Computer Science.
  • Advisor: Chaiporn Thangthong
  • Final project: Factoring with Quadratic Sieve
• The Prince Royal’s College, class of 2007, high school in Mathematics and Science.
  • Extracurricular activities:
    • 2005: Physics Olympiad, 1st camp, Chiang Mai University.
    • 2004: Microsoft IT Youth Challenge, 2nd runner-up.
    • 2003: Astrophysics Olympiad, 2nd camp, Chiang Mai University.

Publications

Journal articles

• Nonthaphat Wongwattanakij, Nattawut Phetmak, Chaiporn Jaikaeo, and Jittat Fakcharoenphol. An improved PTAS for covering targets with mobile sensors. Journal of Combinatorial Optimization, 49(2):20, 2025. (journal) (preprint)
• Nattawut Phetmak and Jittat Fakcharoenphol. Uniformly generating derangements with fixed number of cycles in polynomial time. Thai Journal of Mathematics, 21(4):899–915, Dec. 2023. (journal)
• Nattawut Phetmak and Jittat Fakcharoenphol. Folding every point on a polygon boundary to a point. Algorithms, 16(6):281, 2023. (journal) (preprint)

Conference papers

• Grittin Nuntasombat, Nattawut Phetmak, and Jittat Fakcharoenphol. Robust bichromatic classification in 3D using planes and slices. In 22nd International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON’25). IEEE, 2025. (paper) (preprint)
• Chawin Aiemvaravutigul, Jittat Fakcharoenphol, and Nattawut Phetmak. Building two communication towers over a terrain. In 17th International Joint Conference on Computer Science and Software Engineering (JCSSE’20), pages 150–154. IEEE, 2020. (paper)
• Nattawut Phetmak, Wason Liwlompaisan, and Pruet Boonma. Travel password: A secure and memorable password scheme. In Asian Conference on Intelligent Information and Database Systems (ACIIDS’14), pages 402–411. Springer, 2014. (paper)

Preprints

• Nattawut Phetmak, Grittin Nuntasombat, and Jittat Fakcharoenphol. Covering planar lattices with interior-disjoint unit disks. arXiv preprint arXiv:2607.19764, 2026. (preprint)

Extended abstracts

• Jittat Fakcharoenphol, Grittin Nuntasombat, and Nattawut Phetmak. Covering planar lattices with interior-disjoint unit disks. In 28th Japan Conference on Discrete and Computational Geometry, Graphs, and Games (JCDCGGG’26), 2026. (full version)
• Nattawut Phetmak and Jittat Fakcharoenphol. Folding every point on a polygon boundary to a point. In 24th Japan Conference on Discrete and Computational Geometry, Graphs, and Games (JCDCGGG’22), pages 120–121, 2022. (full version)
• Nattawut Phetmak. Random derangement with fixed number of cycles. In 23rd Thailand-Japan Conference on Discrete and Computational Geometry, Graphs, and Games (TJCDCGGG’20+1), pages 34–35, 2021. (full version)
• Supanut Chaidee, Shuto Nishida, and Nattawut Phetmak. Geometrical analysis of crane game in two dimensions. In 21st Japan Conference on Discrete and Computational Geometry, Graphs, and Games (JCDCGGG’18), pages 43–45, 2018.