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Krishnan Pillaipakkamnatt - Hofstra University. Hempstead, NY, US

Krishnan Pillaipakkamnatt

Professor of Computer Science | Hofstra University


Krishnan Pillaipakkamnatt specializes in data mining, machine learning, and computational learning theory.






HU Office Hours: Krishnan Pillaipakkamnatt on Privacy. HU Office Hours: Krishnan Pillaipakkamnatt on Fake News.




Krishnan Pillaipakkamnatt is a professor in the computer science department at Hofstra University. He holds a B.E. in computer engineering (1989) from Andhra University, India and a Ph.D. in computer science (1995) from Vanderbilt University, Nashville, TN. He joined Hofstra as an assistant professor in 1995.

Professor Pillaipakkamnatt's research interests lie in data mining, and machine learning. More narrowly, he is interested in algorithms that preserve an individual's privacy. A second area of research is in the pedagogy of computational thinking. He is part of a multi-disciplinary team that seeks to introduce computational thinking to high school students through app development in STEM courses.

Industry Expertise (2)



Areas of Expertise (7)


Data Structures

Discrete Mathematics

Operating Systems


Machine Learning

Artificial Intelligence

Education (3)

Vanderbilt University: Ph.D., Computer Science 1995

Indian Institute of Science: M.E., Computer Science 1990

Andhra University: B.E., Computer Science 1989

Articles (5)

A Semi-supervised Learning Approach to Differential Privacy

IEEE 13th International Conference on Data Mining Workshops (ICDMW)

2013 Motivated by the semi-supervised model in the data mining literature, we propose a model for differentially-private learning in which private data is augmented by public data to achieve better accuracy. Our main result is a differentially private classifier with significantly improved accuracy compared to previous work. We experimentally demonstrate that such a classifier produces good prediction accuracies even in those situations where the amount of private data is fairly limited. This expands the range of useful applications of differential privacy since typical results in the differential privacy model require large private data sets to obtain good accuracy.

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Communication-Efficient Privacy-Preserving Clustering

Transactions on Data Privacy

2010 The ability to store vast quantities of data and the emergence of high speed networking have led to intense interest in distributed data mining. However, privacy concerns, as well as regulations, often prevent the sharing of data between multiple parties. Privacy-preserving distributed data mining allows the cooperative computation of data mining ...

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A Practical Differentially Private Random Decision Tree Classifier

IEEE International Conference on Data Mining Workshops (ICDMW)

2009 In this paper, we study the problem of constructing private classifiers using decision trees, within the framework of differential privacy. We first construct privacy-preserving ID3 decision trees using differentially private sum queries. Our experiments show that for many data sets a reasonable privacy guarantee can only be obtained via this method at a steep cost of accuracy in predictions. We then present a differentially private decision tree ensemble algorithm using the random decision tree approach. We demonstrate experimentally that our approach yields good prediction accuracy even when the size of the datasets is small. We also present a differentially private algorithm for the situation in which new data is periodically appended to an existing database. Our experiments show that our differentially private random decision tree classifier handles data updates in a way that maintains the same level of privacy guarantee.

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Sum-of-Squares Heuristics for Bin Packing and Memory Allocation

Journal of Experimental Algorithmics

2008 The sum-of-squares algorithm (SS) was introduced by Csirik, Johnson, Kenyon, Shor, and Weber for online bin packing of integral-sized items into integral-sized bins. First, we show the results of experiments from two new variants of the SS algorithm. The first variant, which runs in time O(n&sqrt;BlogB), appears to have almost identical expected waste ...

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A Secure Clustering Algorithm for Distributed Data Streams

IEEE 7th International Conference on Data Mining Workshops (ICDMW)

2007 We present a distributed privacy-preserving protocol for the clustering of data streams. The participants of the se- cure protocol learn cluster centers only on completion of the protocol. Our protocol does not reveal intermediate candidate cluster centers. It is also efficient in terms of communication. The protocol is based on a new memory- efficient clustering algorithm for data streams. Our experi- ments show that, on average, the accuracy of this algorithm is better than that of the well known k-means algorithm, and compares well with BIRCH, but has far smaller mem- ory requirements.

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