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Aly H.A.,University of Rochester | Aly H.A.,Military Technical College MTC | Sharma G.,University of Rochester
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2013

Pan-sharpening is a common post-processing operation for captured multispectral satellite imagery, where the spatial resolution of images gathered in various spectral bands is enhanced by fusing them with a panchromatic image captured at a higher resolution. Previously proposed pan-sharpening techniques operate on a per-channel basis, sharpening each multispectral band independently based on the panchromatic image, often in an ad hoc manner. In contrast with most prior techniques, we formulate pan-sharpening as the problem of jointly estimating the high resolution multispectral images to minimize the combined squared residual error in physically motivated observation models of the low resolution multispectral and the high resolution panchromatic images. To realize pan-sharpening using our proposed formulation, we develop an iterative algorithm to solve the joint minimization resulting in an overall algorithm with modest computational complexity. We evaluate our proposed algorithm and benchmark it against previously proposed methods using established quantitative measures of SNR, SAM, ERGAS, Q, and Q4 indices. Both the quantitative results and visual evaluation demonstrate that the proposed joint formulation provides superior results compared with pre-existing methods. © 2013 IEEE. Source

Khamis A.,Idaho State University | Naidu D.S.,University of Minnesota | Kamel A.M.,Military Technical College MTC
International Journal of Aerospace Engineering | Year: 2014

This paper presents an efficient online technique used for finite-horizon, nonlinear, stochastic, regulator, and tracking problems. This can be accomplished by the integration of the differential SDRE filter algorithm and the finite-horizon state dependent Riccati equation (SDRE) technique. Unlike the previous methods which deal with the linearized system, this technique provides finite-horizon estimation and control of the nonlinear stochastic systems. Further, the proposed technique is effective for a wide range of operating points. Simulation results of a missile guidance system are presented to illustrate the effectiveness of the proposed technique. © 2014 Ahmed Khamis et al. Source

El-Bealy M.O.,Military Technical College MTC | El-Bealy M.O.,Clausthal University of Technology | El-Bealy M.O.,KTH Royal Institute of Technology | El-Bealy M.O.,Massachusetts Institute of Technology
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2014

The aim of the current article is to elucidate the significant effects of macrosegregation distribution and its level on the different stages of interdendritic crack formation during dendritic solidification in continuously cast steel slabs. Couple formations of macrosegregation and interdendritic crack phenomena during dendritic solidification of peritectic carbon steels have been investigated by metallographic study of collected slab samples and by performing a set of mathematical analyses. The metallographic study involved plant trails to measure slab surface temperature of different secondary spray cooling conditions. Also, macro-microexaminations, measurements of dendrite arm spacing, macrosegregation analysis, and interdendritic distance between the dendrites of collected samples from plant trials have been performed. The experimental results show a fluctuation of carbon segregation with respect to distance from slab surface. These results also reveal that the interdendritic cracks vary with this fluctuation in various nano, macro, and microscales based on the cooling conditions. A mathematical model of heat transfer, solidification, structure evolution, interdendritic strain, macrosegregation, and elementary interdendritic area "EIA" has been developed. This model takes also into account the calculating of interdendritic distance between the dendrites "IDD" to evaluate the interdendritic crack width. The model predictions of different thermal and solidification phenomena show a good agreement with measurements. The results pointed out also that the coupled effect of interdendritic strain and macrosegregation phenomena and their distributions can be considered as the most important tools to evaluate the surface and internal interdendritic cracks in continuously cast steel slabs. The formation mechanisms of different types of interdendritic crack with interdendritic strain patterns and fluctuation of macrosegregation levels during various cooling zones have been explained, and the possible solutions to these problems have been discussed. © 2014 The Minerals, Metals & Materials Society and ASM International. Source

Aly H.A.,Military Technical College MTC
IEEE Transactions on Information Forensics and Security | Year: 2011

This paper deals with data hiding in compressed video. Unlike data hiding in images and raw video which operates on the images themselves in the spatial or transformed domain which are vulnerable to steganalysis, we target the motion vectors used to encode and reconstruct both the forward predictive (P)-frame and bidirectional (B)-frames in compressed video. The choice of candidate subset of these motion vectors are based on their associated macroblock prediction error, which is different from the approaches based on the motion vector attributes such as the magnitude and phase angle, etc. A greedy adaptive threshold is searched for every frame to achieve robustness while maintaining a low prediction error level. The secret message bitstream is embedded in the least significant bit of both components of the candidate motion vectors. The method is implemented and tested for hiding data in natural sequences of multiple groups of pictures and the results are evaluated. The evaluation is based on two criteria: minimum distortion to the reconstructed video and minimum overhead on the compressed video size. Based on the aforementioned criteria, the proposed method is found to perform well and is compared to a motion vector attribute-based method from the literature. © 2010 IEEE. Source

Youssef A.M.M.,Military Technical College MTC
World Journal of Modelling and Simulation | Year: 2013

World Smart materials such as piezoelectric actuators possess useful properties especially in the field of micropositioning. Tracking control accuracy of these systems is limited due to its inherent hysteresis nonlinearity. Designing a precise tracking controller for a piezoelectric actuator with hysteresis nonlinearity is our purpose in this paper.A Bouc-Wen model is used to describe the hysteresis behavior of the actuator. Multi-parameter-optimization techniques are used twice in this paper; first for obtaining a linear model equivalent to the overall nonlinear actuator model, and second for tuning the gains of the PID controller for suppressing the tracking errors and hence getting precision tracking. Several advantages are gained on solving parameter optimization problems using computers; neither reliance on intuition nor experience in control is required, in addition to producing a satisfactory system response with optimal use of effort and time, high convergence speed, high approximation accuracy, high efficiency, and suitability for many kinds of goal functions. Simulation results performed on the nonlinear system verify the efficiency of the proposed method. Source

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