Parampalli Udaya

Cyclic codes and self-dual codes over F/sub 2/+uF/sub 2/

We introduce linear cyclic codes over the ring F/sub 2/+uF/sub 2/={0,1,u,u~=u+1}, where u/sup 2/=0 and study them by analogy with the Z/sub 4/ case. We give the structure of these codes on this new alphabet. Self-dual codes of odd length exist as in the case of Z/sub 4/-codes. Unlike the Z/sub 4/ case, here free codes are not interesting. Some nonfree codes give rise to optimal binary linear codes and extremal self-dual codes through a linear Gray map.

Cocyclic Hadamard codes

We demonstrate that many well-known binary, quaternary, and q-ary codes are cocyclic Hadamard codes; that is, derived from a cocyclic generalized Hadamard matrix or its equivalents. Nonlinear cocyclic Hadamard codes meet the generalized Plotkin bound. Using presemifield multiplication cocycles, we construct new equivalence classes of cocyclic Hadamard codes which meet the Plotkin bound.

An Efficient Clustering Scheme to Exploit Hierarchical Data in Network Traffic Analysis

There is significant interest in the data mining and network management communities about the need to improve existing techniques for clustering multivariate network traffic flow records so that we can quickly infer underlying traffic patterns. In this paper, we investigate the use of clustering techniques to identify interesting traffic patterns from network traffic data in an efficient manner. We develop a framework to deal with mixed type attributes including numerical, categorical, and hierarchical attributes for a one-pass hierarchical clustering algorithm. We demonstrate the improved accuracy and efficiency of our approach in comparison to previous work on clustering network traffic.

A Note on the Optimal Quadriphase Sequences Families

In this note, by using a modification of the families B and C, we obtain a larger family of optimal quadriphase sequences, D over Z4 . In contrast to the families B and C, the family D has the same length and the same maximal nontrival correlation value, but with double the size

A new family of nonbinary sequences with three-level correlation property and large linear span

In this correspondence, we present a new family of nonbinary sequences with three-level nontrivial correlations and large linear complexity. The sequences may be considered as nonlinear analogues of the well-known sequences by Trachtenberg and Helleseth. It is shown that the family is optimal with respect to the Welch bound in terms of root mean square of all nontrivial correlations. We also determine the correlation distribution of the new family.

Privacy and forensics investigation process: The ERPINA protocol

The rights of an Internet user acting anonymously conflicts with the rights of a Server victim identifying the malicious user. The ERPINA protocol, introduced in this paper, allows an honest user communicating anonymously with a Server through a PET, while the identity of a dishonest user is revealed. Prior research failed to distinguish objectively between an honest user and an attacker; and a reliable and objective distinguishing technique is lacking. The ERPINA protocol addresses the reliability issue efficiently by defining from the beginning of the communication what is considered as malicious and what is not.

Generalized Binary Udaya–Siddiqi Sequences

In this correspondence, we present a family of binary 2n sequences of period 2(2n-1) where n is an integer, which can be seen as a generalization of nonlinear binary sequences obtained from Z4 sequences and recently constructed GKW (Gold, Kasami, and Welch)-like sequences. The sequences have low correlations and are useful in code-division multiple-access (CDMA) communication systems and cryptography

Quadriphase sequences obtained from binary quadratic form sequences

The development of the theory of Z4 maximal length sequences in the last decade led to the discovery of several families of optimal quadriphase sequences. In theory, the construction uses the properties of Galois rings. In this paper, we propose a method for constructing quadriphase sequences using binary sequences based on quadratic forms. The study uses only the properties of Galois fields instead of Galois rings. We demonstrate the theory by constructing a new family of Z4 sequences with low correlation property.

Echidna: efficient clustering of hierarchical data for network traffic analysis

There is significant interest in the network management community about the need to improve existing techniques for clustering multi-variate network traffic flow records so that we can quickly infer underlying traffic patterns. In this paper we investigate the use of clustering techniques to identify interesting traffic patterns in an efficient manner. We develop a framework to deal with mixed type attributes including numerical, categorical and hierarchical attributes for a one-pass hierarchical clustering algorithm. We demonstrate the improved accuracy and efficiency of our approach in comparison to previous work on clustering network traffic.

On the Aperiodic Correlation Function of Galois Ring m-Sequences

We define Gauss-like sums over the Galois Ring GR(4, r) and bound them using the Cauchy-Schwarz inequality. These sums are then used to obtain an upper bound on the aperiodic correlation function of quadriphase m-sequences constructed from GR(4, r).Our first bound ?1 has a simple derivation and is better than the previous upper bound of Shanbag et. al. for small values of N. We then make use of a result of Shanbag et. al. to improve our bound which gives rise to a bound ?improved which is better than the bound of Shanbag et. al.These results can be used as a benchmark while searching for the best phases--termed auto-optimal phases--of such quadriphase sequences for use in spread spectrum communication systems. The bounds can also be applied to many other classes of non binary sequences.