Section
Research Areas
Internet and Wireless Network Congestion Control
Congestion control mechanisms in the Internet represent the largest deployed artificial feedback system. Congestion cost at each link (termed price) is measured by a scalar variable and sources have access to the aggregate price of links in their path. Our research explores new methods for explicit price signaling via ECN bit marking, to improve the equilibrium conditions of network fairness, throughput, efficiency, and packet delay. We are developing new bit marking control mechanisms based on statistical decision theory and on diffusion marking methods which we have seen to have a significant impact on network performance. Further, we are seeking new analytical tools for the characterization of congestion control mechanisms. In particular, we are currently exploring the effect of bit marking spectral profiles on congestion control performance. These concepts are being applied to the Internet as well as to Ad-Hoc wireless networks where the broadcast nature of MAC layer communications introduces new challenges and opportunities for congestion control.
Digital Halftoning
Digital halftoning is at the heart of digital printing technology that in general is capable of only rendering limited-tone reproduction. Ink jet, laser, and press printers all rely on advances of digital halftoning. Our work has focused on the development of green noise halftone theory and threshold mask design which are ideally suited for high resolution printers where individual dots are not reliably reproduced and where dot clustering is beneficial. Current work explores halftone visual cryptography, and multitone blue and green noise theory and applications.
Research Group
- Jan Bacca Rodriguez
- Ivan Dario Barrera
- Renwei Ge
- Alvaro Jose Gonzalez
- An He
- Andres Medina
- Michael Wilson
Research Group Alumni
Yinbo Li
Rennwei Ge, “N-ary approximate authentication codes and their applications in secure communications,” in progress.
Liangping Ma, “Signal processing analysis and algorithms for internet congestion control,” 2005.
Karen Bloch, “Signal analysis methods for biological data,’’ 2004. Now with DuPont.
Sebastian Hoyos, “Mixed signal high speed processing solutions for broadband systems and technologies,” 2004. Now with the University of California at Berkeley.
Zhi Zhou, “Advances on digital video and visual cryptography,” 2004. Now with Samsung Research.
Caesar Nino, “New imaging technologies in halftoning: data hiding, color modeling and color matching,” 2002. Now with DuPont.
Jose Luis Paredes, “New robust signal processing tools for multimedian and communications,” Aug. 2001. Faculty Member at the University of Los Andes, Venezuela
Alexander Flaig, “Nearfield spot-beamforming,’’ Aug. 2000. Now with Texas Instruments.
Liehua Xie, “Authentication codes and watermarking for multimedia communications in lossy networks,’’ May 2000. Now with Eye Cast.
Daniel L. Lau (N. C. Gallagher co-supervisor), “Modern digital halftoning,’’ May 1999. Now with the faculty at the University of Kentucky.
Sudhakar Kalluri, “Nonlinear adaptive algorithms for robust signal processing and communication in impulsive environments,’’ Dec. 1998. Now with Intel.
Juan G. Gonzalez, “Robust technologies for wireless communications in non-gaussian environments,’’ (Winner of the Allan P. Colburn Best Dissertation Award as the most outstanding doctoral dissertation in engineering, mathematics, and computer sciences), May 1997. Now with Lucent Bell Laboratories.
David E. Griffith, “Robust time-frequency representations for signals in alpha-stable noise: methods and applications,” December 1997. Now with NIST.
Edwin A. Heredia, “A piecewise polynomial theory for nonlinear signal processing,’’ May 1996. Now with Microsoft.
Yeong T. Kim, “Permutation and combination filter lattices and their applications in nonlinear signal processing,’’ Aug. 1993. Now with Samsung Research Center.
Timothy Hall, “Permutation and combination weighted order stastic filters for image processing,’’ May 1994. Now with NIST.
Martin Mueller, “Tomographic algorithms and synthetic detector arrays,’’ May 1993. Now with Siemens Corp.
Kenneth E. Barner, “Permutation filters: a new group theoretic class of non-linear filters” (Winner of the Allan P. Colburn Best Dissertation Award as the most outstanding doctoral dissertation in engineering, mathematics, and computer sciences), May 1993. Faculty at the University of Delaware.
Shoupu Chen, “Micro-structured adoptive filter theory for robust signal processing,’’ May 1992. Now with Kodak Research.
David C. Brown (C. Ih co-supervisor), “Scene segmentation and definition for autonomous robotic navigation using structured light processing,’’ May 1989. Now with the Army Research Laboratories.
