RESEARCH

Energy-Efficient Electronics and Low-Power Computing: 

• Developed the first clock-cycle-accurate energy measurement and characterization tools for VLSI and computer systems

• Invented the first platform to visualize energy consumption at single clock cycle resolution (1,000+ citations)

• Introduced techniques for software low-power design, including bus encoding, fine-grained DRAM power management, and flash memory optimization, informed by cycle-accurate measurement

• Proposed and validated computing and power conversion co-optimization, exploiting efficiency variability in power converters

• Corrected widely used misleading DVFS transition overhead models; resulting paper cited 150+ times

• Pioneered computing and cooling co-optimization, addressing temperature-dependent leakage power in advanced semiconductor devices

• Extended low-power design to AI data centers, enabling scalable energy-efficient computing

• Developed real-time LCD backlight scaling with color enhancement via hardware support (550+ citations, 70+ U.S. patent citations)

• Applied power-aware techniques to audio systems, wireless sensor nodes, ocean-bottom seismometers, and wearable skin health devices

Energy Harvesting and Alternative Power Sources (Fuel Cells):

• Among the first to introduce fuel cell–battery hybrid power systems, leveraging the high energy density of hydrogen and direct-methanol fuel cells with the load-following capability of batteries

• Developed the first system-level power management framework tailored to the unique characteristics of fuel cells, based on empirical measurements; cited in 150+ research papers

• Proposed online topology reconfiguration architectures and algorithms for energy harvesting systems, including solar cells, solid-oxide fuel cells, and thermoelectric generators

• Designed adaptive systems capable of responding to environmental disturbances and device degradation, in collaboration with chemical and materials engineering faculty and industry partners such as Samsung Electronics and SK Innovation

• Top three papers in this area have received over 180 citations collectively

Hybrid Energy Storage Systems:

At SNU and KAIST:

• Pioneered the concept of hybrid energy storage systems composed of heterogeneous storage elements, designed to maximize performance while mitigating the limitations of individual technologies through high-level system management

• Mapped battery storage problems to computer memory management paradigms, introducing novel architectures for:

  • Charge management (allocation, replacement, migration)

  • Bank reconfiguration

  • Charge interconnect architectures and routing

• Built and demonstrated a 19" rack-scale hardware prototype, validating the system architecture and management strategies

• Published over 30 research papers; work received 1,000+ citations

• Mentored seven student contributors who later became professors in the U.S., Germany, and Korea

At Samsung SDI:

• Led end-to-end product development of utility-scale battery energy storage systems (BESS) for global renewable energy clients

• Oversaw system integration, including:

  • Battery cells, modules, and BMS

  • Thermal management systems (natural convection, forced air, and liquid cooling)

  • Humidity control, remote monitoring, and fire safety systems

• Specialized in battery safety engineering for large-scale energy storage applications

Design Automation of Things:

• First to apply Electronic Design Automation (EDA) methodologies to improve energy efficiency in electric vehicles (EVs) and drones, both at design time and runtime

• Developed algorithms for energy-optimal driving profiles of EVs over variable-slope routes, enabling route-aware efficiency optimization

• Introduced design-time optimization methods for powertrain configuration (e.g., motor and battery sizing) tailored to specific driving missions

• Extended EDA-based optimization to autonomous aerial vehicles, integrating machine learning (ML) techniques for energy-optimal path and velocity planning of delivery drones

• Research demonstrated superior performance compared to conventional energy optimization techniques and received extensive citations from the energy and mobility communities

• Most recent work incorporates AI/ML-based optimization for dynamic mission planning

• Electromobility and drone research efforts have resulted in over 500 citations

Mobility Electrification (Startup Achievement): 

• Directed the design and fabrication of a fully off-road capable electric Jeep Wrangler by replacing the factory internal combustion engine with a custom electric powertrain

  • Project conducted jointly between KAIST and early-stage EMVcon Inc. (California)

• Collaborated with Transamerican Auto Parts (Compton, CA) to fabricate a second electric Jeep Wrangler

  • Became the first fully electric off-road Jeep Wrangler in the United States, showcased at SEMA 2016

• Participated in Jeep Jamboree USA at the Rubicon Trail (2017) with the original Korean-built electric Jeep Wrangler

  • Achieved a historic milestone: first successful Rubicon Trail run completed by an electric vehicle

  • Personally performed all electrical wiring and system integration for the conversion

• Led the electric retrofit of a 600 HP Hyundai Genesis Coupe racing vehicle, representing KAIST and EMVcon, creating a high-performance electric race car

• Directed the design and development of a battery pack for a subcompact electric cargo truck in collaboration with Dpeco Co. Ltd.

  • Utilized Samsung SDI’s 88% nickel-content cylindrical cells and successfully obtained government safety compliance certification

Commercial Automotive and Grid-Scale Storage Battery Product Developments:

• Served as Executive Vice President and Head of Development for all automotive and grid-scale energy storage products at Samsung SDI, one of the world’s leading battery manufacturers

• Led and successfully completed the development of 88% nickel-content products, including:

  • Battery cells for hybrid electric and battery electric vehicles (HEVs and BEVs)

  • Battery modules for both automotive and grid-scale energy storage systems (ESS)

  • Battery packs with integrated battery management systems (BMS)

  • Racks, containers, switchgear, and remote monitoring systems for ESS deployments

• Directed advanced development of next-generation battery chemistries, including:

  • 91% nickel-content battery cells

  • High-density lithium-iron-phosphate (LFP) cells

  • Lithium-iron-manganese-phosphate (LFMP) and cobalt-free cells

  • Participated in early-stage all-solid-state battery development initiatives

• Developed methodologies for precise cycle-life estimation to ensure optimal lifetime without overdesign or warranty violation

  • Addressed aging and reliability factors beyond cell chemistry, including electrode, module, and pack-level design

• Recognized expert in battery safety, with deep experience in thermal runaway propagation prevention at cell, module, pack, and system levels

  • Successfully led safety strategy for UL9540A compliance with 88% nickel-content battery cells in large-scale energy storage systems

• Possesses domain expertise in automotive battery charging, including DC fast charging (DCFC), with a focus on battery aging, safety, and long-term performance under real-world operating conditions

• Directed the development of complete automotive battery pack assemblies for global OEMs including Audi, Stellantis, and AG Volvo, featuring:

  • High-nickel lithium-ion battery cells

  • Advanced BMS technology

  • Integrated thermal runaway containment mechanisms

Advanced high-bandwidth memory:

• Advises on advanced high-bandwidth memory (HBM) technologies for GPU integration and AI applications

• Specializes in power, thermal, and energy optimization, addressing the critical challenges of next-generation AI accelerators and high-performance computing systems

Research Interests

Digital and Embedded Systems Design

• • Microprocessors, memory systems, sensors, actuators, and power converters

  • Real-time control systems with hardware-supported sensing and actuation

  • Cyber-physical systems and networked embedded systems

Low-Power and Sustainable Computing

• • Low-power electronics and energy-efficient computer systems

  • Sustainable computing and systems

  • Design methodologies for energy-aware hardware and software

Electronic Design Automation (EDA) and AI Integration

• • EDA techniques for digital and mixed-signal system design

  • AI/ML for electronics, electrification, and energy system optimization

  • Design Automation of Things (DAoT)

Energy Systems and Electrification

• Battery systems design for automotive, grid-scale energy storage, and electrification

• Hybrid energy storage systems

• Energy harvesting (solar) and clean energy (fuel cells)

• Electrification of Things (EoT)

Sponsored Research (Selected Projects)

Battery Systems & Energy Storage

• Honeycomb Billet (Super Cell) Advance Commissioned Development, Samsung SDI – PI, $2,000,000 (2021)

• Utility-scale Battery Pack Platform Development, Kwangwon-Do e-Mobility – PI, $330,000 (2019–2020)

• Thermal Simulation and Optimization of EV Battery Systems, Samsung SDI – PI, $120,000 (2018–2020)

• Hybrid ESS Simulation Environment and Optimization, Samsung SDI – PI, $60,000 (2018–2019)

• Reconfigurable Hybrid Energy Storage Systems, NRF Leap Program – PI, $1,300,000 (2010–2015)

• Battery Safety and Lifetime Optimization, various Samsung & SK Innovation-funded programs (multiple years)

Electrification, Vehicles, and Drones

• Design and Management Automation of Drones (Total Cost Optimization), NRF Leap Program – PI, $883,000 (2021)

• High-Performance Electric Racing Car Development, KAIST – PI, $300,000 (2016–2018)

• Extreme Off-Road Electric Vehicle Conversion Kits, NRF – Co-PI, $591,000 (2016–2019)

• Design Automation of Things for Low-Power EVs, NRF Leap Program – PI, $883,000 (2015–2018)

• Vehicle Blind Spot Warning System, Sindo Ricoh – PI, $7,420 (2008)

• Coordinated Multi-ECU Chassis Control, Hyundai Mobis – PI, $47,500 (2007–2008)

Energy Harvesting & Clean Energy

• Flexible Thermoelectric Generator Applications, NRF – Co-PI, $358,000 (2015–2018)

• Reconfigurable SOFC Systems, SK Innovation – PI, $83,000 (2013–2014)

• Hydrogen Generator with Sodium Borohydride, KITECH – PI, $40,000 (2006–2007)

• Direct Methanol Fuel Cell BOP System Development, Samsung SAIT – PI, $55,000 (2008–2009)

Low-Power Systems, Displays, and Embedded Platforms

• Low-Power OLED Display Systems, NRF – PI, $200,000 (2011–2014)

• Low-Power TFT LCD Controller Development, ETRI – PI, $32,000 (2008)

• Apollo Testbed Design & System Integration, University of Southern California – PI, $87,000 (2002–2003)

• Portable Digital Convergence Platform, Ministry of Commerce, Industry, and Energy – PI, $220,826 (2002–2005)

Memory Systems and SoC

• Phase Change Memory File Systems, Ministry of Knowledge and Economy – PI, $180,000 (2011–2014)

• Next-Gen NAND Flash System Architecture, Samsung Electronics – PI, $40,000 (2008–2009)

• Design Space Exploration for Advanced Flash Memories, Samsung Electronics – PI, $80,000 (2007–2008)

• SoC Co-Simulation Tool and NAT Optimization, Samsung Electronics – PI, $60,000 (2003–2004)

Power & Thermal Management

• Thermal Management of Smartphone Processors, Samsung Electronics – PI, $45,000 (2012–2013)

• Power Measurement & Characterization for Low-Power Systems, Samsung Electronics – PI, $93,000 (2005)

• DC-DC Converter Efficiency Analysis, Samsung Electronics – PI, $13,450 (2004–2005)