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A new structure preserving model order reduction technique for second order systems in limited frequency interval is presented. Frequency limited Gramians (FLGs) and corresponding continuous time algebraic lyapunov equations (CALEs) are developed. For solution of CALEs and Cholesky factorization of FLGs, computationally efficient approximation scheme is proposed. Multiple transformations based on balancing of frequency limited position or velocity Gramians are defined in order to compute Hankel singular values (HSVs). Frequency limited second order balanced truncation based on magnitudes of HSVs is performed for order reduction. Moreover, stability conditions for reduced order models (ROMs) are stated and algorithms for achieving stability in ROMs are proposed. Results are compared with existing technique to certify the usefulness of the proposed technique.  相似文献   
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Journal of Computational Electronics - Laves-phase (C15) binary intermetallics RFe2 (R?=?Eu, Gd and Tb) are studied using various potentials in the domain of density functional theory...  相似文献   
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Multidimensional Systems and Signal Processing - The paper presents a content based image retrieval scheme based on feature extraction and weighing. Features are extracted using frequency adder...  相似文献   
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Transdermal patches loaded with ramipril and repaglinide were prepared with the ambition to develop matrix-type transdermal drug delivery system for enhanced permeability and hence improved bioavailability. Different formulations were designed by intermittent concentrations of hydroxypropyl methylcellulose K4M as hydrophilic polymer and ethyl cellulose as hydrophobic polymer. Solvent casting method was used for the fabrication of transdermal patches. Oleic acid and propylene glycol were used to enhance permeability along with polyethylene glycol 400 as plasticizer. Newly designed patches were then evaluated for various physicochemical and mechanical properties. Compatibility studies were performed by Fourier transformed infrared spectroscopy which did not reveal any interaction between drug and polymers. Crystalline nature of drugs was confirmed when they were subjected to X-ray diffraction study and surface morphological studies using scanning electron microscopy. Transdermal patches were of good mechanical strength with folding endurance of more than 300-fold and 100% flatness. Percent drug contents of ramipril and repaglinide ranged from 90 to 105%, i.e., analogous to official limits. In vitro and ex vivo permeation studies were executed using franz diffusion cell. The cumulative amount of drug permeated through skin was 55.22–112.72% for repaglinide and 73.14–91.46% for ramipril. The release behavior of the permeated drug was analyzed by the application of model-dependent approaches. The results showed that Korsmeyer–Peppas model was found to be dominating in most of the formulations and drugs followed diffusion mechanism. It could be concluded that hydroxypropyl methylcellulose K4M and ethyl cellulose has great potential for ramipril and repaglinide as a vector for transdermal drug delivery effectively because of the formation of smooth surfaces of patches, high folding endurance, and entrapment efficiency with the ability to release the drugs in sustained manner.  相似文献   
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This work addresses, numerical method based on Haar wavelets and finite differences to solve two dimensional linear, nonlinear Sobolev and non-linear generalized Benjamin–Bona–Mahony–Burgers (NGBBMB) equations. The temporal part is discretized using finite differences while spatial part is approximated by two dimensional Haar wavelets. With this strategy, computing solution of two dimensional PDEs reduces to computing solution of linear system of algebraic equations. Collocation approach is then applied to determine the wavelet coefficients from linear system. This paper shows that two dimensional Haar wavelets are suitable and effective for two dimensional linear and non-linear PDEs. For validation of the proposed scheme different problems have been solved and error norms L,L2 are computed. Computation verifies that current scheme has good outcome.  相似文献   
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Digital government security infrastructure design challenges   总被引:1,自引:0,他引:1  
Information age technologies provide enormous opportunities for a government to transform its functions into the digital arena. Doing so taps the wellspring of information technology benefits that have driven down off-the-shelf component costs and fuelled an unprecedented improvement rate in the cost-performance ratio. We can view a digital government (DG) as an amalgam of heterogeneous information systems in which government agencies and public and private sectors exchange a high volume of information. Designing security systems for a digital government's multidomain environment requires a careful balancing act between providing convenient access and carefully monitoring permissions  相似文献   
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