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Showing papers by "Ghulam Ishaq Khan Institute of Engineering Sciences and Technology published in 2007"


Journal ArticleDOI
TL;DR: Experiments on standard images indicate that such watermark shaping functions could be developed that are cover image independent and enhance imperceptibility and offer high resistance against removal and interference attacks of Checkmark benchmark.

90 citations


Journal ArticleDOI
TL;DR: Experimental results obtained using orthorhombic ABO3 perovskites demonstrate that the proposed prediction model is more efficient, robust and fast than those based on artificial neural networks.

56 citations


Journal ArticleDOI
TL;DR: In this article, a modified half-off-energy-shell resonant resonant $R$-matrix method was applied to the low-energy bare-nucleus cross section of the human body.
Abstract: The low-energy bare-nucleus cross section for $^{15}\mathrm{N}$$(p,\ensuremath{\alpha})$$^{12}\mathrm{C}$ is extracted by means of the Trojan horse method applied to the $^{2}\mathrm{H}$($^{15}\mathrm{N}$,$\ensuremath{\alpha}$$^{12}\mathrm{C}$)$n$ reaction at ${E}_{\mathrm{beam}}=60$ MeV. For the first time we applied the modified half-off-energy-shell resonant $R$-matrix method that takes into account off-energy-shell effects and initial- and final-state interactions. In particular it has been shown that inclusion of Coulomb $^{15}\mathrm{N}$$\text{\ensuremath{-}}d$ scattering and off-shell effects do not affect the determination of the astrophysical factor. Also the simple plane-wave approximation used in previous analyses is justified. The results extracted via the Trojan horse method are compared to direct data in the same energy region and show very good agreement in the energy interval 70--312 keV. These results confirm the extrapolations of the $S$ factor reported in literature.

50 citations


Proceedings ArticleDOI
11 Apr 2007
TL;DR: In this paper, a time-domain zero-forcing equalizer (ZFE) for wavelet packet based OFDM (WOFDM) is proposed and the performance comparison of DFT-OFDM and WPT is given for an arbitrary FIR channel with different types of wavelet packets.
Abstract: In conventional DFT based orthogonal frequency division multiplexing (OFDM), cyclic prefix (CP) is used to avoid the inter symbol interference (ISI) caused by a time dispersive channel. A solution has been proposed in literature, which involves replacing DFT with wavelet packet transform (WPT) in communication systems. WPT does not require CP and has the attraction of having much lower side lobes. However, in wavelet based multicarrier systems, channel equalization remains an open research area. In this article, a time-domain zero-forcing equalizer (ZFE) for wavelet packet based OFDM (WOFDM) is proposed. The performance comparison of DFT-OFDM and WOFDM is given for an arbitrary FIR channel with different types of wavelet packets. Simulation results show improvement in bit error rate (BER) performance for WOFDM.

29 citations


Journal ArticleDOI
TL;DR: In this article, a three-dimensional nonlinear finite-element analysis of gasketed flange joint was carried out using ANSYS commercial software to investigate fundamental joint characteristics, joint strength and sealing capability under combined internal pressure, and variable steady state thermal loading.
Abstract: Performance of a flange joint is characterized mainly due to its "strength" and "sealing capabilit." A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. The effect of steady state thermal loading is a well recognized problem and makes the problem more complex under combined application of internal pressure and temperature. To investigate fundamental joint characteristics, joint strength and sealing capability under combined internal pressure, and variable steady state thermal loading, a three-dimensional nonlinear finite-element analysis of gasketed flange joint is carried out using ANSYS commercial software. Reduced joint strength is concluded due to the flange rotation resulting in flange yielding under bolt up and applied operating conditions. Reduced joint sealing is concluded due to the variation in gasket seating or contact pressure due to bolt load variation. Flange rotation, bolt bending, and joint relaxation concluded fatigue and dynamic behavior in the gasketed joint. These effects are observed to be more pronounced at higher temperatures. Verification of finite-element model with available classical theories is also performed and discussed.

21 citations


Journal ArticleDOI
TL;DR: A comparison of the spatially adaptive grid-refinement approach with that of uniform meshing approach for various benchmark cases confirms its superiority in greatly enhancing the accuracy of the solution without increasing the number of unknown coefficients.

20 citations


Journal ArticleDOI
TL;DR: In this paper, a study of proper Weyl collineations in Kantowski-Sachs and Bianchi type III space-times is given by using the rank of the 6 6× Weyl matrix and direct integration techniques.
Abstract: A study of proper Weyl collineations in Kantowski-Sachs and Bianchi type III space-times is given by using the rank of the 6 6× Weyl matrix and direct integration techniques. Studying proper Weyl collineations in each of the above space-times, it is shown that there exists no such possibility when the above spacetimes admit proper Weyl collineations.

15 citations


Journal ArticleDOI
TL;DR: Application of such a hybrid technique performing both selection and intensity estimation of a pixel demonstrates substantial improvement in the image quality as compared to the adaptive Wiener filter and existing fuzzy-kriging approaches.
Abstract: We present a general formulation based on punctual kriging and fuzzy concepts for image restoration in spatial domain. Gray-level images degraded with Gaussian white noise have been considered. Based on the pixel local neighborhood, fuzzy logic has been employed intelligently to avoid unnecessary estimation of a pixel. The intensity estimation of the selected pixels is then carried out by employing punctual kriging in conjunction with the method of Lagrange multipliers and estimates of local semi-variances. Application of such a hybrid technique performing both selection and intensity estimation of a pixel demonstrates substantial improvement in the image quality as compared to the adaptive Wiener filter and existing fuzzykriging approaches. It has been found that these filters achieve noise reduction without loss of structural detail information, as indicated by their higher structure similarity indices, peak signal to noise ratios and the new variogram based quality measures.

13 citations


Proceedings ArticleDOI
06 Jul 2007
TL;DR: Experimental results have proved that the embedded data with the proposed scheme is visually transparent, robust against unintentional or malicious attacks such as frames deleting, frames inserting and frame statistical averaging, and 3-D interleaving has significantly improved the robustness of the proposed Scheme against temporal attacks.
Abstract: Requirements for digital watermarking are mainly application dependent. Robustness is one of the main requirements for many watermarking applications. In this paper a blind discrete wavelet transform (DWT) based video watermarking algorithm for copyright protection is proposed. We have embedded a meaningful watermark invisibly into uncompressed video. The watermark is embedded in high frequency sub-band coefficients of the DWT to improve the invisibility of the marked video sequence. The watermark is first scrambled and then encoded to minimize the error probabilities during watermark detection. We have applied 2-D automorphic transform and BCH error correction coding on the binary image for scrambling and encoding the watermark respectively before the watermark embedding. We have applied key based pseudo random 3-D interleaving on the coefficients selected for watermark insertion. We have also embedded the frame number as the synchronization information instead of using the sliding correlation as proposed in [1, 5]. Experimental results have proved that the embedded data with the proposed scheme is visually transparent, robust against unintentional or malicious attacks such as frames deleting, frames inserting and frame statistical averaging. 3-D interleaving has significantly improved the robustness of the proposed scheme against temporal attacks. The watermark embedded in such way is high bit rate and thus more robust. The series of experiments conducted has revealed the effectiveness and usefulness of the proposed watermark generation and embedding strategy.

9 citations


Journal ArticleDOI
TL;DR: In this article, the authors considered a scheme of independent allocation of particles of s types into an infinite number of cells and proved the asymptotic normality of these statistics under weaker conditions than those known.

8 citations


Journal IssueDOI
TL;DR: The proposed technique consists of using fuzzy logic as a mapping function to decide whether a pixel needs to be krigged or not and genetic programming is used to evolve an optimal pixel intensity-estimation function for restoring degraded images.
Abstract: We present an intelligent technique for image denoising problem of gray level images degraded with Gaussian white noise in spatial domain. The proposed technique consists of using fuzzy logic as a mapping function to decide whether a pixel needs to be krigged or not. Genetic programming is then used to evolve an optimal pixel intensity-estimation function for restoring degraded images. The proposed system has shown considerable improvement when compared both qualitatively and quantitatively with the adaptive Wiener filter, methods based on fuzzy kriging, and a fuzzy-based averaging technique. Experimental results conducted using an image database confirms that the proposed technique offers superior performance in terms of image quality measures. This also validates the use of hybrid techniques for image restoration. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 224–231, 2007

Journal ArticleDOI
TL;DR: In this paper, the effect of a samarium addition on the shape memory behavior of Fe-14Mn-3Si-10Cr-5Ni (wt%) alloys has been studied.
Abstract: The effect of a samarium addition on the shape memory behavior of Fe–14Mn–3Si–10Cr–5Ni (wt%) alloys has been studied. It is found that the addition of samarium resulted in 27% increase in the shape memory effect. It was noticed that the addition of samarium had also improved the mechanical properties, increased c / a ratios and inhibited the formation of ά which is considered detrimental for the shape memory behavior. The results of alloys with and without samarium additions are compared to elucidate the beneficial response of samarium.

Book ChapterDOI
01 Jan 2007
TL;DR: The proposed technique uses Dual Tree Complex Wavelet Transform based features of video frames for the purpose of shot change detection, key frame selection and video indexing, and uses correlation based distance metric as it produced better results for this kind of feature similarity.
Abstract: — In this paper a novel technique of content based video retrieval is presented. The proposed technique uses Dual Tree Complex Wavelet Transform (DTCWT) based features of video frames for the purpose of shot change detection, key frame selection and video indexing. For shot change detection consecutive frame difference is computed, shot change is reported when the difference exceeds a certain threshold. For keyframe selection a frame is to be selected which is not part of shot transition using k-mean clustering of DTCWT feature vectors. Video shots are indexed using DTCWT features of the selected keyframes. Video query is processed by comparing the features of shot with the features database of the shots. For the purpose of features similarity we have used correlation based distance metric as it produced better results for this kind of feature similarity. The results are compared the results with classical techniques and it is shown how dual tree complex wavelet transform based features performed better. The whole framework uses similar kind of feature which makes it simple and efficient.— CBVR, Video Indexing, Shot Boundaries, Key Frames

Proceedings ArticleDOI
11 Apr 2007
TL;DR: A weighted polling method is used to fuse the output of individual covariant discriminant classifiers, trained on features based on pseudo-amino add composition of proteins, which predicted accuracies are higher than that of the existing schemes.
Abstract: Prediction of subcellular localization of proteins is an important step in genome annotation and in search for achieving novel drug targets. Conducting experiments for extracting information about protein sub cellular localization is both time consuming and costly effort. Machine learning approaches, especially, ensemble of classifiers, providing efficient and reliable mechanism of computational prediction are thus highly desired In this context, we propose a modification to the approach proposed in [K. C. Chou, J. Cell. Biol. 99(2006)517]. We have used a weighted polling method to fuse the output of individual covariant discriminant classifiers. The individual classifiers are trained on features based on pseudo-amino add composition of proteins. Three methods of verifications; re-substitution, Jackknife, and independent data set tests have been employed and give over all accuracies of 87.13%, 71.15% and 74.90% respectively. The predicted accuracies are higher than that of the existing schemes.

Posted Content
TL;DR: In this paper, a study of proper Weyl projective curvature collineations in FRW k = 0 space-time is given using the rank of Weyl curvature matrix and direct integration techniques.
Abstract: A study of proper Weyl projective curvature collineations in FRW k=0 space-time is given using the rank of Weyl projective curvature matrix and direct integration techniques. It is shown that a very special class of the above space-time admits proper Weyl projective curvature collineation.