Seminar by Prof. Gopal Lakhani
Hierarchical Representation for Text Compression and Searching
Prof. Gopal Lakhani
Department of Computer Science
Texas Tech University, Lubbock, TX
and
Visiting Faculty, CSE Department
Indian Institute of Technology Kanpur
Date: Wednesday, January 28, 2003
Time: 03:45 PM
Venue: CS-101
Abstract
Text compression programs are widely used for file size reduction. We will provide an overview of the core algorithms used in these programs and give some results on their entropy coding. We will then show that given an arbitrary size string, one can develop a BNF grammar of "minimal" size, which generates the given string as its language precisely. This hierarchical representation can be used for finding repeating substrings, which is very important for many applications. Some improvements to coding of the grammar will also be discussed.
About the Speaker
Dr. Gopal Lakhani has received his BSc degree from Univ. of Calcutta in 1964, MSc (Mathematics) from Jiwaji Univ. in 1966, and PhD (Mathematics) from IIT Kanpur in 1973. He received another MS degree (Computer Science) from Univ of Illinois in 1978. He is currently a faculty member in the Computer Science Department at Texas Tech University. His research interests include data compression, multimedia systems, and distributed system security. The main focus of his recent research is to study and improve JPEG algorithms for still-image compression. Which deals with reduction of blocking artifact effect, improving the Huffman coding of JPEG images, measurement of compression defects, and LZW compression.