Sundaram Suresh

Reversible Watermarking Algorithm Using Sorting and Prediction

This paper presents a reversible or lossless watermarking algorithm for images without using a location map in most cases. This algorithm employs prediction errors to embed data into an image. A sorting technique is used to record the prediction errors based on magnitude of its local variance. Using sorted prediction errors and, if needed, though rarely, a reduced size location map allows us to embed more data into the image with less distortion. The performance of the proposed reversible watermarking scheme is evaluated using different images and compared with four methods: those of Kamstra and Heijmans, Thodi and Rodriguez, and Lee et al. The results clearly indicate that the proposed scheme can embed more data with less distortion.

A sequential learning algorithm for self-adaptive resource allocation network classifier

This paper addresses sequential learning algorithm for self-adaptive resource allocation network classifier. Our approach makes use of self-adaptive error based control parameters to alter the training data sequence, evolve the network architecture, and learn the network parameters. In addition, the algorithm removes the training samples which are similar to the stored knowledge in the network. Thereby, it avoids the over-training problem and reduces the training time significantly. Use of misclassification information and hinge loss error in growing/learning criterion helps in approximating the decision function accurately. The performance evaluation using balanced and imbalanced data sets shows that the proposed algorithm generates minimal network with lesser computation time to achieve higher classification performance.

Risk-sensitive loss functions for sparse multi-category classification problems

In this paper, we propose two risk-sensitive loss functions to solve the multi-category classification problems where the number of training samples is small and/or there is a high imbalance in the number of samples per class. Such problems are common in the bio-informatics/medical diagnosis areas. The most commonly used loss functions in the literature do not perform well in these problems as they minimize only the approximation error and neglect the estimation error due to imbalance in the training set. The proposed risk-sensitive loss functions minimize both the approximation and estimation error. We present an error analysis for the risk-sensitive loss functions along with other well known loss functions. Using a neural architecture, classifiers incorporating these risk-sensitive loss functions have been developed and their performance evaluated for two real world multi-class classification problems, viz., a satellite image classification problem and a micro-array gene expression based cancer classification problem. To study the effectiveness of the proposed loss functions, we have deliberately imbalanced the training samples in the satellite image problem and compared the performance of our neural classifiers with those developed using other well-known loss functions. The results indicate the superior performance of the neural classifier using the proposed loss functions both in terms of the overall and per class classification accuracy. Performance comparisons have also been carried out on a number of benchmark problems where the data is normal i.e., not sparse or imbalanced. Results indicate similar or better performance of the proposed loss functions compared to the well-known loss functions.

Lift coefficient prediction at high angle of attack using recurrent neural network

In this paper, identification of dynamic stall effect of rotor blade is considered. Recurrent Neural Networks have the ability to identify the nonlinear dynamical systems from training data. This paper describes the use of recurrent neural networks for predicting the coefficient of lift

Self regulating particle swarm optimization algorithm

(C_Z)

A sequential multi-category classifier using radial basis function networks

at high angle of attack. In our approach, the coefficient of lift

Sequential Projection-Based Metacognitive Learning in a Radial Basis Function Network for Classification Problems

(C_Z)

Meta-cognitive Neural Network for classification problems in a sequential learning framework

obtained from the experimental results (wind tunnel data) at different mean angle of attack

Metacognitive learning in a fully complex-valued radial basis function neural network

\theta_{mean}

A Metacognitive Neuro-Fuzzy Inference System (McFIS) for Sequential Classification Problems

is used to train the recurrent neural network. Then the recurrent neural network prediction is compared with experimental ONERA OA212 airfoil data. The time and space complexity required to predict