D. Roy Choudhury

Unconstrained handwritten character recognition based on fuzzy logic

This paper presents an innovative approach called box method for feature extraction for the recognition of handwritten characters. In this method, the binary image of the character is partitioned into a fixed number of subimages called boxes. The features consist of vector distance (γ) from each box to a fixed point. To find γ the vector distances of all the pixels, lying in a particular box, from the fixed point are calculated and added up and normalized by the number of pixels within that box. Here, both neural networks and fuzzy logic techniques are used for recognition and recognition rates are found to be around 97 percent using neural networks and 98 percent using fuzzy logic. The methods are independent of font, size and with minor changes in preprocessing, it can be adopted for any language.

Gerschgorin Theorem and its Applications in Control System Problems

In this paper, we have presented application of Gerschgorin theorem in relative stability analysis of a system represented by a polynomial. We have also presented the applications of Gerschgorin Theorem in reduced order modeling by identifying time scales and stabilization for linear time invariant systems.

An efficient designed robust adaptive congestion controller for ABR traffic in ATM network

In the computer networks, congestion occurs when the resource demands exceeds the capacity, which the network can provide. The presence of too many packets in the network, which the network is not able to cope with due to its limited resources and it begins losing packets, gives birth to the situation called congestion. The aims of this paper is to analyze the performance of Robust Adaptive Congestion Control algorithm for ABR traffic in ATM networks and modify this algorithm for better performance. The main goal of ABR traffic control is to provide fairness among all the VCs with a minimal cell loss ratio and maximum utilization of the network.

Universal Weights for Maximally-Flat FIR Approximations of Amplitude Response: [1/ω]

An efficient design of linear phase, FIR structure for amplitude response, approximating [1/ω] (an integrating Hilbert transformer), suitable for the midband frequency range has been proposed. Mathematical formulas for computation of weights have been derived. These weights turn out to be invariant to the order of the filter, and are, therefore, universal in nature. This property is expoited to harness the proposed design with facility of variable orders of the sturcture maintaining the optimality criteria for all possible orders. A versatile structure for such a purpose has also been given.