SangHyun Bang 방상현

Student Researcher

• Assisted Multi-Armed Bandit / reinforcement-learning research — theory analysis, experiment organization, project support
• Built the habit of viewing problems quantitatively through experiment design and interpretation

Research Intern

• Bandit Algorithm / Reinforcement Learning research intern

Management Planning Intern

• Supported management-planning work — experienced how business and data connect to decisions

• Staged the LLM recommendation — LLM recommends only the category (cat3) while ranking runs in a Spring algorithm; cat3Filter reuse removes LLM re-calls on same-condition requests → isolates cost & failure propagation
• Split place-list pagination into Offset / Cursor (createdtime + contentid composite key, Base64 cursor, size+1 for hasNext)
• Separated a search read model — search_text denormalization + MySQL FULLTEXT (ngram)
• Built observability — AOP request/exception collection, fingerprint dedup → Slack alerts, correlation id, JaCoCo·Qodana (GitHub Actions)
• Java 21 / Spring Boot 3.5 / Spring Security·OAuth2·JWT / JPA / MySQL 8 / AWS S3·CloudFront / Docker Compose

• Owned the auth/authorization flow in an MSA on Spring Cloud Gateway·Redis·Kafka·OPA
• Diagnosed intermittent 403s as a structural "JWT permission vs user-state mismatch," not a gateway error
• Propagated state changes via Kafka events wired to OPA Bundle refresh, removing the root cause