Current Issue : April - June Volume : 2012 Issue Number : 2 Articles : 8 Articles
This paper presents a new state-space method for spectral estimation that performs decimation by any factor, it makes use of the full\r\nset of data and brings further apart the poles under consideration, while imposing almost no constraints to the size of the Hankel\r\nmatrix (model order), as decimation increases. It is compared against two previously proposed techniques for spectral estimation\r\n(along with derived decimative versions), that lie among the most promising methods in the field of spectroscopy, where accuracy\r\nof parameter estimation is of utmost importance. Moreover, it is compared against a state-of-the-art purely decimative method\r\nproposed in literature. Experiments performed on simulated NMR signals prove the new method to be more robust, especially for\r\nlow signal-to-noise ratio....
In this note we wish to compliment some recent enhancements in the cosmological literature by implementing notions of Einstein’s conformal geometry and its role in analysing the dynamical structured cosmos. In particular, we shall discuss some tensor structures like; Yang and Bach tensors, which are responsible to generate any generic metric in the form of Einstein one and hence produce Einstein’s equations. Besides, we shall outline some conformally transformed Einstein’s geometric configurations which play vitally crucial roles in the fabrication of many discrete versions of Einstein’s equation. Finally, we shall employ Ricci flow mechanism to evolve conformally deformed Einstein’s geometric configurations as the non-linear heat diffusion expressions....
The progression of a cerebral aneurysm involves degenerative arterial wall remodeling. Various hemodynamic parameters are\r\nsuspected to be major mechanical factors related to the genesis and progression of vascular diseases. Flow alterations caused by\r\nthe insertion of coils and stents for interventional aneurysm treatment may affect the aneurysm embolization process. Therefore,\r\nknowledge of hemodynamic parameters may provide physicians with an advanced understanding of aneurysm progression and\r\nrupture, as well as the effectiveness of endovascular treatments. Progress in medical imaging and information technology has\r\nenabled the prediction of flow fields in the patient-specific blood vessels using computational analysis. In this paper, recent\r\ncomputational hemodynamic studies on cerebral aneurysm initiation, progress, and rupture are reviewed. State-of-the-art\r\ncomputational aneurysmal flow analyses after coiling and stenting are also summarized. We expect the computational analysis\r\nof hemodynamics in cerebral aneurysms to provide valuable information for planning and follow-up decisions for treatment....
Epilepsy is a medical term which indicates a common neurological disorder characterized by seizures, because of abnormal\r\nneuronal activity. This leads to unconsciousness or even a convulsion. The possible etiologies should be evaluated and treated.\r\nTherefore, it is necessary to concentrate not only on finding out efficient treatment methods, but also on developing algorithm to\r\nsupport diagnosis. Currently, there are a number of algorithms, especially nonlinear algorithms. However, those algorithms have\r\nsome difficulties one of which is the impact of noise on the results. In this paper, in addition to the use of fractal dimension as\r\na principal tool to diagnose epilepsy, the combination between ICA algorithm and averaging filter at the preprocessing step leads\r\nto some positive results. The combination which improved the fractal algorithm become robust with noise on EEG signals. As a\r\nresult, we can see clearly fractal properties in preictal and ictal period so as to epileptic diagnosis....
The evolution of the cutaneous structure after topical treatment with P63 antiaging complex, assessed with high frequency\r\nultrasound, is studied by means ofmulticriteria optimization model. Due to the fact that the impact of the treatment may influence\r\nthe quality of life, a medical index which measures, from this point of view, the efficacy of the treatment is given, also taking into\r\naccount medical and economical aspects....
There have been proposed several compressed imaging reconstruction algorithms for natural and MR images. In essence, however,\r\nmost of them aim at the good reconstruction of edges in the images. In this paper, a nonconvex compressed sampling approach\r\nis proposed for structure-preserving image reconstruction, through imposing sparseness regularization on strong edges and also\r\noscillating textures in images. The proposed approach can yield high-quality reconstruction as images are sampled at sampling\r\nratios far below the Nyquist rate, due to the exploitation of a kind of approximate 0 seminorms. Numerous experiments are\r\nperformed on the natural images and MR images. Compared with several existing algorithms, the proposed approach is more\r\nefficient and robust, not only yielding higher signal to noise ratios but also reconstructing images of better visual effects....
We present a new approach based on the formulation of the integrodifferential quadrature method (hereafter called IDQ) to\r\nhandle Volterra�s and Fredholm�s equations. This approach is constructed and tested with some realistic numerical examples using\r\nthe basic computational aspects....
We explore the consequences of metrically decomposing a finite phase space, modeled as a d-dimensional lattice, into disjoint\r\nsubspaces (lattices). Ergodic flows of a test particle undergoing an unbiased random walk are characterized by implementing\r\nthe theory of finite Markov processes. Insights drawn from number theory are used to design the sublattices, the roles of lattice\r\nsymmetry and system dimensionality are separately considered, and new lattice invariance relations are derived to corroborate the\r\nnumerical accuracy of the calculated results.We find that the reaction efficiency in a finite system is strongly dependent not only on\r\nwhether the system is compartmentalized, but also on whether the overall reaction space of the microreactor is further partitioned\r\ninto separable reactors.We find that the reaction efficiency in a finite system is strongly dependent not only on whether the system\r\nis compartmentalized, but also on whether the overall reaction space of the microreactor is further partitioned into separable\r\nreactors. The sensitivity of kinetic processes in nanoassemblies to the dimensionality of compartmentalized reaction spaces is\r\nquantified....
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