Jung-Sang Ahn

안정상 (in Korean)

Software Engineer at eBay.
LinkedIn
Github
Resume (Jul, 2017)

Interests

• Indexing systems, file systems, storage systems, operating systems, embedded systems.
• Problem solving, optimizing performance.
• Electric/acoustic guitar, finger-style guitar, band session, song writing, recording/mixing/mastering.
• Snowboarding, go-kart.

Employment and Education

• Member of Technical Staff, Distributed Systems, eBay, 2017 - present.
• Senior Software Engineer, Couchbase, 2015 - 2017.
• Ph.D. in Computer Science (Computer Architecture Lab.), KAIST, 2010 - 2015.
• M.S. in Computer Science (Computer Architecture Lab.), KAIST, 2008 - 2010.
• B.S. in Computer Science, KAIST, 2004 - 2008.
  • Presidential scholarship, the Korean government.
• Daejeon Science High School, 2002 - 2004.

Experiences

  eBay

• Development of next-generation distributed database core engine
  • Eventually/strongly consistent replication engine based on Paxos, Raft, and variants.
  • Active-active (multi-master) replication and conflict resolution logic.
  • Storage engine across geo-distributed replicas.

  Couchbase

• Key-value storage engine
  • Original inventor of ForestDB
  • MVCC key-value storage engine based on append-only index structure.
  • Development of storage engine for NoSQL server & mobile platform.
  • Optimizing file system and disk I/O patterns.
  • Designing efficient index structures.

  KAIST

• Index structures for block devices
  • Designing flash-optimized index structure for FTL (Flash Translation Layer) in SSD controller.

• Mobile/embedded device kernel
  • Designing lightweight encryption file system for Android platform.
  • Linux kernel optimization.

Personal Projects

• Generic lock-free Skiplist container
  
  • Pure C-style container based on Skiplist, supporting any type of data.
  • Lock-free: multiple readers and writers.

• Generic AVL-tree container
  
  • Pure C-style container based on AVL-tree, supporting any type of data.
  • Up to 3x faster than STL set or map.

• Test Suite
  
  • Lightweight (a single header file) test suite for C++ program.

• Simple Logger
  
  • Lightweight and lock-free logging library for C++ program.

• Latency Collector
  
  • Lightweight embedded library to measure latencies of C++ program.

• Hex Dump

Publications and Patents

• ForestDB: A Fast Key-Value Storage System for Variable-Length String Keys
  Jung-Sang Ahn, Chiyoung Seo, Ravi Mayuram, Rahim Yaseen, Jin-Soo Kim, and Seungryoul Maeng
  IEEE Transactions on Computers, 2016.

• Low-Overhead User Data Protection for Smartphones using Plaintext Cache
  Jung-Sang Ahn and Seungryoul Maeng
  Mobile Security Technologies (IEEE Symposium on Security and Privacy), 2013.

• μ*-Tree: An Ordered Index Structure for NAND Flash Memory with Adaptive Page Layout Scheme
  Jung-Sang Ahn, Dongwon Kang, Dawoon Jung, Jin-Soo Kim, and Seungryoul Maeng
  IEEE Transactions on Computers, 2013.

• Indexing Method for Flash Memory
  Jaesoo Lee, Jung-Sang Ahn, Jin-Soo Kim, and Dawoon Jung
  Patent Filed No. 13/273,501 (October 4, 2011), United States.

• Indexing Method for Flash Memory
  Jaesoo Lee, Jung-Sang Ahn, Jin-Soo Kim, and Dawoon Jung
  Patent Filed No. 10-2010-0100464 (October 14, 2010), Korea.

Honors and Awards

• Third Place, ACM SIGMOD Programming Contest, 2012.
  A Multi-Dimensional Indexing System

• Finalist, ACM SIGMOD Programming Contest, 2011.
  A Durable Main-Memory Index Using Flash

• Bronze Prize, Samsung Humantech Paper Award, 2008.

• Silver Prize, Samsung Humantech Paper Award, 2004.

• Honorable Mention, Samsung Humantech Paper Award, 2003.

• Gold Medal, KOI (Korea Olympiad in Informatics), 2001.

Contact Information

• E-mail: jungsang . ahn [at] gmail . com
• YouTube Channel
• SoundCloud