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

  MTS at eBay

• Next-generation distributed database platform

  Software Engineer at Couchbase

• Storage layer improvement
  • Designing/revising storage engine (fetching/storing key-value pairs from/to disks) architecture.
  • Optimizing disk I/O patterns.

• ForestDB project
  • Open source standalone storage engine based on a newly proposed index structure.
  • The original inventor: designed and developed the index structure (HB+trie), and other fundamental concepts.
  • Paper: ForestDB: A Fast Key-Value Storage System for Variable-Length String Keys, IEEE TC 2016.

  Research Assistant at KAIST

• UX-oriented mobile software platform
  • A huge academic project in collaboration of 11 graduate school laboratories and 2 companies including LG electronics, funded by the Korean government.
  • Worked on core mobile kernel part, designed and developed a lightweight encryption file system for Android platform.
  • Paper: Low-Overhead User Data Protection for Smartphones using Plaintext Cache, IEEE Most 2013.

• Development of a basis technology for trustworthy computing
  • Funded by the Korean government.

• Exploiting object-based interface for SSDs
  • Funded by Samsung.

• A high-performance FTL for large-capacity flash SSDs
  • Development of fast and memory-efficient flash translation layer (FTL) for commercial SSDs, funded by Samsung.
  • Worked on mapping and indexing part, designed and developed a flash-optimzied index structure, called μ∗-tree, which is the main mapping structure for the FTL.
  • Paper: μ*-Tree: An Ordered Index Structure for NAND Flash Memory with Adaptive Page Layout Scheme, IEEE TC 2013.

• Development of environment for ubiquitous/embedded system software
  • Research on development tool for next-generation flash memory.
  • Funded by the Korean government.

  Teaching Assistant at KAIST

• CS310 Embedded Computer Systems (won TA Excellence Award), Fall 2010.
• CS211 Digital System and Lab, Spring 2010.
• CS330 Operating System and Lab (won TA Excellence Award), Fall 2009.
• CS330 Operating System and Lab, Spring 2009.
• CS330 Operating System and Lab, Fall 2008.
• CS320 Programming Language, Spring 2008.

Personal Projects

• Generic Skiplist container
  
  • Skiplist implementation that can be used as set or map, containing any type of data.
  • Completely lock-free for concurrent readers and writers.
  • Scalable throughput according to the number of threads.

• Partial lock
  
  • Grab a Lock on a small part of a large shared data, without blocking other locks on non-overlapping parts.

• C-style generic AVL-tree container
  
  • An ordered index that can be used as set or map, containing any type of data.
  • Can be used in pure C.
  • Up to 3x faster than STL set or map.

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