Video Architectures

We have developed new architectures for high-performance video processing, both for our smart camera application and for other video applications. With Vijaykrishnan of Penn State, we studied the power and performance properties of motion estimation algorithms.

Selected papers:

• Shengqi Yang, Wayne Wolf, and N. Vijaykrishnan, "Search speed and power driven integrated software and hardware optimizations for motion estimation algorithms," in Proceedings, International Conference on Multimedia and Exhibition, IEEE, 2004.
• Wayne Wolf, Tiehan Lv, and I. Burak Ozer, "An architectural design study for a high-speed smart camera," in Proceedings, 4th Workshop on Media and Streaming Processors, IEEE, 2002.
• Jason Schlessman and Wayne Wolf, "Leakage power considerations for processor array-based vision systems," in Proceedings, SASIMI 04, 2004.

Networks-on-chips

Networks-on-chips are structured interconnect for systems-on-chips. We studied wave pipelining as a NoC technique and showed that it can save energy as well as run faster. With Joerg Henkel and Srimiat Chakradar of NEC, we developed application-specific architectures for networks-on-chips.

Selected papers:

1. J.Henkel, W.Wolf, and S.Chakradhar, "On Chip Networks: A scalable communication-centric embedded system design paradigm," in Procedings, VLSI Design 2004, IEEE, 2004.
2. J. Xu, W. Wolf, T. Lv, J. Henkel, and S. Chakradhar, "A case study in networks-on-chip design for embedded video," in Proceedings, DATE 04, IEEE Computer Society Press, 2004.
3. Jiang Xu and Wayne Wolf, "A wave-pipelined on-chip interconnect structure for networks-on-chips," in Proceedings, Hot Interconnects 2003, IEEE, 2003.
   
   

Code Compression

We have studied code compression algorithms and architectures for many years. Most recently, we have concentrated on code compression for VLIW architectures. We developed profile-driven methods that selectively compress code. We also showed how to use LZW-style algorithms for code compression by making use of variable-sized blocks.

Selected papers:

1. C. H. Lin, W. Wolf, and Y. Xie, "LZW-based code compression for embedded systems," in Proceedings, DATE 04, IEEE Computer Society Press, 2004.
2. Yuan Xie, Wayne Wolf, and Haris Lekatsas, "Profile-driven code compression," in Proceedings, DATE '03, IEEE Computer Society Press, 2003, pp. 462-467.
3. Yuan Xie and Wayne Wolf, "Code compression for VLIW using variable-to-fixed coding," in Proceedings, ISSS 2002, IEEE, 2002.

Low-Power Design

We developed a bus encoding technique that reduces power consumption and can be efficiently implemented. This method uses dictionary encoding, so it does not have to transmit the code words even though they are derived from the data being transmitted.

Selected papers:

• Tiehan Lv, Joerg Henkel. Haris Lekatsas, and Wayne Wolf, "A dictionary-based en/decoding scheme for low-power data busses," IEEE Transactions on VLSI Systems, 11(5), October 2003, pp. 943-951.

Secure Processors

We developed a new approach to the design of microprocessors that are resistant to power attacks. A power attack analyzes power supply dynamic behavior to interpret events within the processor, taking advantage of the fact that different operations take different amounts of energy. We use dynamic voltage and frequency scaling to hide the energy consumption of microprocessor operations:

(c) 2005 IEEE

Our approach makes processor activity less visible with no significant energy consumption penalty and a modest performance penalty. Dynamic voltage frequency scaling is well-known and commercially available so this technique is applicable today.

Selected papers:

• Shengqi Yang, Wayne Wolf, Vijaykrishnan Narayanan, Dimitrios Serpanos, and Yuan Xie, "Power-attack resistant cryptosystem design: a dynamic voltage and frequency switching approach," in Proceedings, DATE '05 Designers Forum, 2005.