Department of Computer Science University of Houston Houston, TX 77204-3475 Phone: (713)743-3359 Fax: (713)743-3335 Email: coscel@cs.uh.edu (preferred)
Ernst L. Leiss received degrees in computer science and in mathematics from the University of Waterloo and the Technical University of Vienna. He joined the Department of Computer Science at the University of Houston in 1979; in 1985 he became the director of the Research Computation Laboratory which he headed until 1994. He (co)authored well over a hundred peer-reviewed papers; he wrote Principles of Data Security (1982, Plenum), Software Under Siege: Viruses and Worms (1990, Elsevier), Parallel and Vector Computing: A Practical Introduction (McGraw-Hill, 1995), and Language Equations (Springer, 1999). He contributed articles on data-security and on computer viruses to the Encyclopedia of Physical Science and Technology (1987 and 1990, Academic Press). Since 1983, he has been (co)PI on research funded at over $2.5 million. His research interests range from vector/parallel computing to data security, geophysical data processing, databases, and theory of formal languages. He is a member of ACM and EATCS, a Senior Member of IEEE, and an Active Member of SEG.
This talk draws on practical experiences in programming a wide variety of commercial parallel systems. It reviews different classifications of parallelism, discusses available hardware, and contrasts vector computing with parallel computing. In particular, it highlights the development of software for vector and parallel systems and concludes that parallel computing, despite the availability of parallel hardware, is still significantly handicapped by the lack of tools to which users have become accustomed in vector computing.
This talk gives an overview of three aspects of data security, namely statistical databases, authorization systems and crypto systems. In particular, it reviews cryptography, from classical or symmetric encryption to public-key or asymmetric encryption and presents (fairly informally) the underlying principles of the RSA scheme for public-key cryptography. Then it discusses the problem of authentication, including password approaches, digital signatures, and interrogative protocols.
Starting with an overview of several viruses, including their properties, origins, and flaws, this talk presents precursors of viruses and worms and changes in the computing milieu that have materially contributed to the phenomenon. It then gives definitions of the intruders, reviews the Internet attack (time permitting), and comments on detection and prevention.
Watermarks provide a means of embedding information into digital videos that can be used for a variety of purposes, such as establishing ownership, tracing origin of copies, etc. We outline an approach that permits a significant increase of the amount of information that can be accommodated in a watermark, namely time-variant watermarks. The approach is formulated assuming video represented in an MPEG format. Implementation issues of time-variant watermarks are discussed, as are their advantages over the usual time-invariant watermarks, with emphasis on defeating attacks using filtering, cropping, resizing, and other standard methods used to defeat watermarks, such as changing existing frames, as well as new attacks, such as removing or adding frames.
All talks can be given in English, Spanish, or German.