Young Jin Nam

Visiting Professor, Ph.D
Department of Computer Science & Engineering
University of Minnesota, Twin-Cities
200 Union St. SE, Minneapolis, MN 55455
youngjin at, 612-408-3165(cell)

/About Myself/Personal/Areas of Interests/Summary of Current Research/Work Experiences/Publications/Patents/Education

About Myself

    I have been currently working with Prof. David Du's research group as a visiting professor at the University of Minnesota in the department of Computer Science and Engineering, since December 2010. I have been also an Associate Professor in the School of Computer and Information Technology, Daegu University in Korea, since 2004. I have developed my strong theoretical background and hands-on experiences in intelligent storage system designs and developments from RAID to hybrid storage (PCM/SSD/HDD), since 1994.

Areas of Interests
  • Data Deduplication, Key-Value Store, HPC Checkpointing
  • Storage QoS, High-performance Storage Architecture
  • New Storage Technologies: SSD/Flash, Shingled Write Disks, Phase Change Memory

Summary of Current Research
Work Experiences
  • Visiting Professor, Dept. of Computer Science & Eng., University of Minnesota, Dec. 2010 - present
    • Working with Prof. David H.C. Du's research group on the following research topics:
    • Data deduplication read performance enhancement: inventing a new performance metric called Chunk Fragmentation Level (CFL) and devising CFL-based dynamic chunk defragmentation & chunk caching
    • Reliability-aware data deduplication: defining chunk loss probability & chunk loss severity and devising reliability-aware deduplication algorithms
    • Highly scalable VM cloud storage architecture: aiming to support a very large number (1,000,000+) of VM images by providing high scalability through a cloud-wide Hadoop file system (HDFS) over distributed shared storage connected with cost-effective dedicated I/O networks (and storage capacity & energy savings with cloud-wide data deduplication & live VM migrations)
    • Flash-based Key-Value store: multiple Bloom Filter based memory-frugal, high-throughput (key-lookup) KV store design
    • High-performance checkpoint storage for HPC applications: SSD layer for high-performance checkpointing with two-phase I/Os & data deduplication for (intra/inter processes) checkpoint data
  • Associate Professor, School of Computer & IT, Daegu University, Daegu, Korea, Sep. 2004 - present
    • Teaching the classes of computer architecture & digital design
    • Working with six graduate students (including two Ph.D students) on the following research topics:
    • Virtual USB drive architecture for mobile devices: providing a typical USB flash memory interface to a mobile device while giving seamless accesses to networked storage (iSCSI) and cloud storage (Amazon S3)
    • Highly scalable VM cloud storage architecture: HDFS/Xen prototype setup, its performance & scalability evaluation, effective placement of multiple VMs on shared storage to minimize performance interference
    • Hybrid storage (HDD/iSCSI/WAN storage) & its contents caching for digital signage systems
  • Visiting Researcher, IBM Almaden Research Center, San Jose, CA, Feb. 2001 - Oct. 2001
    • Worked for developing a storage QoS controller
    • Responsible for prototyping a storage QoS controller for fiber-channel based shared storage, throttling multiple I/O request streams from different clients (implemented on a Linux machine)
    • Proposed an efficient throttling algorithm (token-bucket based, selectively on and off) and evaluated its performance under various I/O workloads (random/sequential with different sizes) and SLAs
    • Analyzed a SPC-1 storage benchmark tool and integrated it with a C++-based storage simulator
  • Research Assistant, POSTECH, Pohang, Korea, Mar. 1998 - Feb. 2004
    • Worked for developing a RAID controller & designing dynamic storage QoS control
    • Developed a x86-based RAID controller: based on VxWorks RTOS, admin/configuration tool (5.4K lines), SCSI target driver (11K lines), FC target driver (9K lines), RAID0-5 algorithms, RAID6(RM2) algorithm with lazy parity update (presented at ICPP2002 & FAST2002WIP), an adaptive HWM/LWM-based destaging algorithm for RAID write cache (presented at PRDC2002) (39K lines)
    • Designed dynamic QoS control consisting of a set of distributed disk QoS schedulers and data migrator
  • Visiting Researcher, Novell/SCO, Summit/Florham Park, NJ, Mar. 1995 - Mar. 1996
    • Worked for a development of a serverized Unix SVR4 over Chorus micro-kernel
    • Ran a set of test suites for the developed OS code and documented bug reports (with analysis)
    • Participated in a series of code reviews
  • Research Staff, Electronics & Telecommunications Research Institute, Korea, Feb. 1994 - Feb. 1998
    • Worked for a micro-kernel based OS for a massively parallel computer called SPAX (
    • Responsible for porting a boot loader on a bare board (each compute/IO node) and kernel-level distributed lock manager (ORACLE parallel DB), writing device drivers (TTY, cross-bar switches), and serverizing I/O device drivers of the Unix SVR4/Chorus micro-kernel over distributed compute/IO nodes
  • Member of Strategic Planning Committee, Ministry of Knowledge Economy, Korea , Jul. 2009 - Jan. 2011
    • Responsible for planning 2010/2011 strategic national technical roadmap for intelligent home appliances and convergence devices

Selected Publications
  • BloomStore: Efficient Bloom-Filter based Key-Value Store for Indexing of Data Deduplication on Flash Memory, Submitted to USENIX FAST 2012 (Guanlin Lu, Young Jin Nam, David H.C. Du)
  • HotDataTrap: A Sampling-based Hot Data Identification Scheme for Flash Memory," ACM Symposium on Applied Computing, March 2012 (Dongchul Park, Biplob Debnath, Young Jin Nam, David H.C. Du)
  • Block Link File System Supporting Fast Editing/Writing for Large-Sized Multimedia Files, IEEE International Conference on Consumer Electronics (ICCE2012), January 2012 (Seung-Wan Jung, Young Jin Nam, Dae-Wha Seo)
  • Virtual USB Drive: A Key Component for Smart Home Storage Architecture, IEEE International Conference on Consumer Electronics (ICCE2012), January 2012 (Young Jin Nam, Dongchul Park, David H.C. Du)
  • Hybrid Storage Architecture for Networked Digital Signage Systems, Lecture Notes in Computer Science (UNESST2011), December 2011 (Young Jin Nam, Soonhwan Jung, Youngkyun Park)
  • Amortized Linux Ext3 File System with Fast Writing after Editing for WinXP-Based Multimedia Application. IEICE Transactions on Information and Systems, September 2011 (Seung-Wan Jung, Young Jin Nam, Dae-Wha Seo)
  • Reliability-Aware Deduplication Storage: Assuring Chunk Reliability and Chunk Loss Severity, The First International Workshop on Energy Consumption and Reliability of Storage Systems (IGCC/ERSS2011), July 2011 (Young Jin Nam, Guanlin Lu, David H.C. Du)
  • Chunk Fragmentation Level: An Effective Indicator for Read Performance Degradation in Deduplication Storage, IEEE International Symposium of Advances on High Performance Computing and Networking (AHPCN2011), September 2011 (Young Jin Nam, Guanlin Lu, Nohhyun Park, Weijun Xiao, David H.C. Du)
  • Design and Evaluation of an Efficient Proportional-share Disk Scheduling Algorithm, Journal of Future Generation Computer Systems, April 2006 (Young Jin Nam, Chanik Park)
  • Regulating I/O Performance of Shared Storage with a Control Theoretical Approach, The 21st IEEE Mass Storage Systems Symposium/12th NASA Goddard Conference on Mass Storage Systems and Technologies (MSST2004), April 2004 (Han Deok Lee, Young Jin Nam, Chanik Park)
  • A Self-adjusting Destage Algorithm with High-Low Water Mark in Cached RAID5, IEICE Transactions on Information and Systems, December 2003 (Young Jin Nam, Chanik Park)

Selected Patents
  • More than 30 patents (including two international patents) have been issued and registered.
  • US Patent, 20100048139, Battery Power Consumption Control, Feb. 2010 (Provided is a power control method in which a remaining battery time of a portable device can be ensured, and a portable device using the method.)

Personal Information
  • Citizenship: South Korea
  • Marriage: Married with two children