TAYSTUDIO operation notes · tool guides · tech/career · useful posts
Why does the sample variance divide by n-1 instead of n? Two views — correcting underestimation (bias) and degrees of freedom — to get at the essence of variance.
Connecting the nature of probability through three concepts — uncertainty, variability, and variance — including the intuition for why variance is defined as 'distance from the mean.'
![[Summit] AWS Summit Review](assets/posts/aws-summit-2024/cover.webp)
AWS Summit Seoul 2024 — walking the booths and sorting the trends into three buckets: generative-AI serving (chatbots, email, copilots, image-gen), multi-cloud CMP, and API gateway / middleware. 'Ideas converge — UX and performance is where companies actually win.'
A 64-bit unique ID generator that doesn't collide even when many servers generate IDs at once — the design intent of Twitter Snowflake (Sign·TimeStamp·DataCenter·Server·Serial, 5 segments), a Java bit-operation implementation, and a 10,000 TPS test architecture (Nginx·Netty·MongoDB).
![[Admissions] KAIST Graduate Written Exam (Mechanical Engineering) — Review (1)](assets/posts/kaist-grad-mech-written-set1/cover.webp)
KAIST Mechanical Engineering grad school written exam (Aug 2019) — Set 1 (5 problems, 2 hours) recap. Math · Solid · Dynamics · Thermo · Fluid (one problem each). ODE, Von-Mises stress, Work & Energy, Bernoulli + Energy equation, hydrostatic force on curved surface.
![[Admissions] KAIST Graduate Written Exam (Mechanical Engineering) — Review (2)](assets/posts/kaist-grad-mech-written-set2/cover.webp)
KAIST Mechanical Engineering grad school written exam (Aug 2019) — Set 2 (5 problems, 2 hours) recap. Eigen value/vector · Strength design procedure · rigid-body Work & Energy · max-work thermo problem · Navier-Stokes Couette flow.
![[New Grad] SK AX (formerly C&C) - Coding Test & Interview (Final Acceptance) Review](assets/posts/career-sk-ax-newgrad-2023/cover.jpg)
SK Inc. AX (formerly C&C) 2023 H2 new graduate SW hiring — application, coding test (4 problems), SKCT psychological, 1-day interview (discussion + job/personality).
![[New Grad] Hyundai Motor — CarCloud Role — Coding Test + 1st Interview (Rejected) Recap (2023 H1)](assets/posts/career-hyundai-carcloud-newgrad-2023/cover.jpg)
Hyundai Motor 2023 H1 new-grad recruitment for CarCloud role — aptitude + AI interview (ViewInter, 12 questions) + coding test (Softeer, Java, 3 problems) + 1st interview (30-min pre-assignment + technical 1:3). Self-graded 4/6 well-answered; still rejected at the 1st round. Keyword recap: API Gateway, WebFlux, encryption.
![[New Grad] LG Electronics - Coding Test & Interview (Final Rejection) Recap](assets/posts/career-lg-electronics-newgrad-2022/cover.jpg)
2022 H2 LG Electronics new-grad recruitment (Gasan R&D Campus, H&A division) — coding test (Programmers, Java, 3 problems: full · full · partial) + aptitude + 1st interview (research presentation) + 2nd interview (executive + English OPIc) → finally rejected. A case where role misalignment shaped the outcome.
![[New Grad] KT DS - Coding Test & Interview (Final Offer) Recap](assets/posts/career-ktds-newgrad-2021/cover.jpg)
2021 H2 KT DS new-grad recruitment, Application SW Dev/Operations role — aptitude + coding test (Programmers, Python, 3 problems: 2 algo + 1 SQL) + 1-day interview (pre-assignment PT + technical 4:1 + executive group). A muddy technical interview that somehow ended in a final offer.