Avinash C. Kak (Marathi अविनाश काक) (also known as Avi Kak, born 1944) is a professor of Electrical and Computer Engineering at Purdue University who has done pioneering research in several different aspects of information processing. His most noteworthy contributions deal with algorithms, languages, and systems related to networks (including sensor networks), robotics, computer vision, etc.
Lecture notes on computer and network security
These lecture notes have become Google dominant during the last six years, as can be seen by Google search on strings like "lecture notes on computer security", "lecture notes on network security", "computer and network security", etc. One of the biggest reasons for their popularity might be the fact that they are updated every year at the beginning of each year. These notes provide comprehensive depth plus breadth overview of computer and network security. In the context of network security related work by Avi Kak, it will be interesting to see if the new technique proposed by Padmini Jaikumar and Avi Kak  will provide a robust solution to the difficult problem of botnet detection in computer networks.
Significant contributions to robotics and computer vision
With regard to the groundbreaking contributions made by Kak and his collaborators: In 1989, Chen and Kak published 3D-POLY that is still the fastest algorithm for recognizing 3D objects in depth maps. In 1992, Kosaka and Kak published FINALE, which is considered to be a computationally efficient and highly robust approach to vision-based navigation by indoor mobile robots. In 2003, a group of researchers that included Kak developed a tool for content-based image retrieval that was demonstrated by clinical trials to markedly improve the performance of radiologists. This remains the only clinically evaluated system for content-based image retrieval for radiologists.
A talk by Avinash Kak (available as a PDF file) that is making the rounds on the internet is titled (provocatively/amusingly) Why Robots Will Never Have Sex. This talk is supposed to be a rejoinder to those who believe that robots/computers will someday take over the world.
Significant contributions to image reconstruction algorithms
The SART algorithm (Simultaneous Algebraic Reconstruction Technique) proposed by Andersen and Kak in 1984 has had a major impact in CT imaging applications where the projection data is limited. As a measure of its popularity, researchers have proposed various extensions to SART: OS-SART, FA-SART, VW-OS-SART, SARTF, etc. Researchers have also studied how SART can best be implemented on different parallel processing architectures. SART and its proposed extensions are used in emission CT in nuclear medicine, for dynamic CT, for holographic tomography, etc. Convergence of the SART algorithm was theoretically established in 2004 by Ming Jiang and Ge Wang in their paper "Convergence of the simultaneous algebraic reconstruction technique (SART)" published in the IEEE Transactions on Image Processing, Vol. 12, August 2003, pp. 957–961.
His book Principles of Computerized Tomographic Imaging, now re-published as a classic in Applied Mathematics by SIAM (Society of Industrial and Applied Mathematics), is widely used in courses dealing with modern medical imaging. It is one of the most frequently cited books in the literature on image reconstruction. His other co-authored book Digital Picture Processing is also considered to be a classic and has been one of the most widely referenced sources in literature dealing with digital image processing and computer vision.
His more recent books are a part of his Object Trilogy Project The first book of the trilogy, Programming with Objects: A Comparable Presentation of Object-Oriented Programming with C++ and Java, presents a comparative approach to the teaching and learning of two large object-oriented languages, C++ and Java. The second book, Scripting with Objects: A Comparative Presentation of Object-Oriented Scripting with Perl and Python, does the same with Perl and Python. The last, Designing with Objects is presumably currently in the works.
- Padmini Jaikumar and Avinash Kak, "A Graph-Theoretic Framework for Isolating Botnets in a Network," Security and Communication Networks, 2012
- C. H. Chen and A. C. Kak, "A Robot Vision System for Recognizing 3-D Objects in Low-Order Polynomial Time," IEEE Transactions on Systems, Man, and Cybernetics, pp. 1535–1563, November/December 1989
- Akio Kosaka and Avinash Kak, "Fast Vision-Guided Mobile Robot Navigation using Model-Based Reasoning and Prediction of Uncertainties," Computer Vision, Graphics, and Image Processing -- Image Understanding, pp. 271–329, November 1992
- Alex Aisen, Lynn Broderick, Helen Winter-Muram, Carla Brodley, Avinash Kak, Christina Pavlopoulou, Jennifer Dy, Chi-Ren Shyu, and Alan Marchiori, "Automated Storage and Retrieval of Thin-Section CT Images to Assist Diagnosis: System Description and Preliminary Assessment," Radiology, Vol. 228, No. 1, pp. 265–270, July 2003
- Anders Andersen and Avinash Kak, "Simultaneous Algebraic Reconstruction Technique (SART): A Superior Implementation of ART," Ultrasonic Imaging, 1984
- Avinash Kak and Malcolm Slaney, Principles of Computerized Tomographic Imaging SIAM (Society of Industrial and Applied Mathematics) Press(1988)
- *Azriel Rosenfeld and Avinash Kak, Digital Picture Processing Academic Press(1982)
- The Objects Trilogy Project
- Avinash Kak, Programming With Objects: A Comparative Presentation of Object Oriented Programming with C++ and Java John Wiley and Sons (2003)
- Avinash Kak, "Scripting with Objects: A Comparative Presentation of Object-Oriented Scripting with Perl and Python" John Wiley and Sons (2008)