Current Research Projects

My research interests span several areas including low-power system design, hardware-software co-design of real-time embedded systems, Very Large Scale Integrated circuits (VLSI), nano-scale computing, and computational medicine. The underlying characteristic common to these areas is the employment of algorithm and/or hardware design and analysis techniques to solve problems arising from real-world applications.

Codesign of Real-Time Embedded Systems:

A major portion of my research activities centers around the theme of design automation for electronic systems (EDA). More than 90% of the computer systems in use are embedded systems consisting of both hardware and software components. Advances in process technology and ever increasing demand of smarter, cheaper, cooler embedded systems have fueled the needs for better methodologies and tools to design and implement such systems. I am mostly interested in solving problems related to real-time embedded systems commonly found in many applications such as communication devices, transportation machines, entertainment appliances, and medical instruments.

My student, Gang Quan, and I received the Best Paper Award from 2001 Design Automation Conference for our work on power-aware scheduling for fixed-priority real-time systems.
Here are some of the projects that I have worked on:
More detailed description about these projects can be found via the link to my research lab: Embedded System Design Lab

VLSI and Nano-Scale Computing:

Another of my research interests is related to VLSI. I have studied problems in high-level synthesis, VLSI floorplanning, and design of special VLSI circuitry for computationally intensive systems.

Here are some of my papers in this area.

 In the last several of years, I have entered an emerging research area related to VLSI, i.e., the study of alternative computing models at the nano scale. As the physical and economic limits of scaling CMOS devices (the building blocks of VLSI circuits) seem to be ever closer, it is imperative to investigate other computing alternatives at the nanometer scale. %Notre Dame's Center for Nano Science and Technology is one of %the leading groups in the world in this research field. %In particular, I so far have focused on the study of one particular nano-scale computing device, i.e., Quantum-dot Cellular Automata (QCA). We are the first to propose a QCA-based programmable structure and the first to propose defect and fault modeling methods for such circuits. We have also started to examine power related issues for QCA circuits. Our work has demonstrated to the EDA community that the community can play an active role in researching emerging technologies, e.g., guiding physical level exploration and assisting in overcoming physical implementation constraints. Currently, we are investigating in more depth fault tolerance issues for QCA-based circuits and reconfigurable computing with QCA devices.

Here are my papers related to QCA.

Algorithm and Hardware Design for Medical and Other Applications

In recent years, I have become interested in the design, analysis, and implementation of algorithmic techniques for solving problems that arise in medical applications. In particular, I have worked on computationally intensive problems in radiation therapy, a minimally invasive surgical procedure that uses a set of focused beams of radiation to destroy tumors. I have studied two specific problems in radiation therapy: radiation treatment planning and radiation dose calculation, both of which are key steps in radiation therapy and are computationally challenging.

Radiation treatment planning defines the best radiation beam arrangements and time settings to destroy the target tumor without harming surrounding healthy tissues. At the core of radiation treatment planning is a set of substantially non-trivial optimization problems. In many ways, they resemble some optimization problems that appear in the electronic design automation field.

Dose calculation is used to predict the amount of energy to be delivered to a patient by a radiation treatment. Fast and accurate dose calculation is crucial in evaluating the effectiveness of a treatment plan and making necessary adjustment to it. However, accurate 3D dose calculation can take hours on a modern computer, which hinders the effective evaluation of a treatment plan and increases the uncertainties of the treatment. Medical physicists resort to various approximation techniques to speed up the calculation but must tolerate large errors. We are exploring hardware-assisted implementation alternatives, particularly System-on-a-Programmable-Chip (SoPC) based solutions. Our preliminary results are quite promising.

Here are some of my papers in this area.


Acknowledgement:

The above research projects have been supported by a number of sources including

National Science Foundation

  • Computer System Research Program
    •  DARPA/ITO
  • Embeddable Systems
    •  Army Research Office

    Hewlett Packard

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