Amit Mitra | University of Minnesota - Twin Cities (original) (raw)

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Papers by Amit Mitra

Research paper thumbnail of Frequency estimation of undamped exponential signals using genetic algorithms

Research paper thumbnail of Estimating the Parameters of Multiple Chirp Signals

Research paper thumbnail of Asymptotic properties of the least squares estimates of 2-D exponential signals.(English) Zbl 0847.93069

Research paper thumbnail of Study of dynamic relationships between financial

Research paper thumbnail of Applred Mathematrcs and Computatron mmrmm

Research paper thumbnail of ¢ Sc| enceD| rect M

Research paper thumbnail of The vievvs. opinions and/or findings contained inthis re on are those of the author (s) and should not be construed as

Research paper thumbnail of Commun Nonlinear Sci Numer Simulat

Research paper thumbnail of Applied Multivariate Analysis

Research paper thumbnail of M-estimator-based robust estimation of the number of components of a superimposed sinusoidal signal model

ABSTRACT In this paper, we consider the problem of estimating the number of components of a super... more ABSTRACT In this paper, we consider the problem of estimating the number of components of a superimposed nonlinear sinusoids model of a signal in the presence of additive noise. We propose and provide a detailed empirical comparison of robust methods for estimation of the number of components. The proposed methods, which are robust modifications of the commonly used information theoretic criteria, are based on various M-estimator approaches and are robust with respect to outliers present in the data and heavy-tailed noise. The proposed methods are compared with the usual non-robust methods through extensive simulations under varied model scenarios. We also present real signal analysis of two speech signals to show the usefulness of the proposed methodology.

Research paper thumbnail of Identifying patterns of socio-economic development using self-organizing maps

Research paper thumbnail of On parameter estimation of two dimensional chirp signals

Research paper thumbnail of Sequential estimation of two dimensional sinusoidal models

Estimating the unknown parameters of a two-dimensional (2-D) sinusoidal signal is an important an... more Estimating the unknown parameters of a two-dimensional (2-D) sinusoidal signal is an important and a difficult problem. In this paper, we propose a simple sequential procedure for estimating the unknown frequencies and amplitudes of the 2-D sinusoidal components when the ...

Research paper thumbnail of Integration of Financial Markets in India: An Empirical Investigation

Research paper thumbnail of A wavelet filtering based estimation of output gap

Research paper thumbnail of Forecasting business cycle movements using wavelet filtering and neural networks

Research paper thumbnail of Detecting the number of signals for an undamped exponential model using cross-validation approach

Research paper thumbnail of Genetic algorithm and M-estimator based robust sequential estimation of parameters of nonlinear sinusoidal signals

Research paper thumbnail of Cellular, molecular and immunological mechanisms in the pathophysiology of vein graft intimal hyperplasia

Immunology and cell biology, 2006

Coronary artery disease, leading to myocardial infarction and ischaemia, affects millions of pers... more Coronary artery disease, leading to myocardial infarction and ischaemia, affects millions of persons and is one of the leading causes of morbidity and mortality worldwide. Invasive techniques such as coronary artery bypass grafting are used to alleviate the sequelae of arterial occlusion. Unfortunately, restenosis or occlusion of the grafted conduit occurs over a time frame of months to years with a gradual reduction in patency, especially in vein grafts. The events leading to intimal hyperplasia (IH) formation involve numerous cellular and molecular components. Various cellular elements of the vessel wall are involved as are leucocyte-endothelial interactions that trigger the coagulation cascade leading to localized thrombus formation. Subsequent phenotypic modification of the medial smooth muscle cells and their intimal migration is the basis of the lesion formation that is thought to be propagated by an immune-mediated reaction. Despite intense scrutiny, the pathophysiology of IH...

Research paper thumbnail of Temporal PTEN inactivation causes proliferation of saphenous vein smooth muscle cells of human CABG conduits

Journal of cellular and molecular medicine, 2009

Internal mammary artery (IMA) coronary artery bypass grafts (CABG) are remarkably resistant to in... more Internal mammary artery (IMA) coronary artery bypass grafts (CABG) are remarkably resistant to intimal hyperplasia (IH) as compared to saphenous vein (SV) grafts following aorto-coronary anastomosis. The reason behind this puzzling difference still remains an enigma. In this study, we examined the effects of IGF-1 stimulation on the PI3K-AKT/PKB pathway mediating proliferation of smooth muscle cells (SMCs) of IMA and SV origin and the specific contribution of phosphatase and tensin homologue (PTEN) in regulating the IGF-1-PI3K-AKT/PKB axis under these conditions. Mitogenic activation with IGF-1, time-dependently stimulated the phosphorylation of PI3K and AKT/PKB in the SV SMCs to a much greater extent than the IMA. Conversely, PTEN was found to be significantly more active in IMA SMCs. Transient overexpression of PTEN in SMCs of SV and IMA inhibited AKT/PKB activity and upstream of AKT/PKB, caused a reduction of IGF-1 receptors. Downstream, PTEN overexpression in SV SMCs induced the...

Research paper thumbnail of Frequency estimation of undamped exponential signals using genetic algorithms

Research paper thumbnail of Estimating the Parameters of Multiple Chirp Signals

Research paper thumbnail of Asymptotic properties of the least squares estimates of 2-D exponential signals.(English) Zbl 0847.93069

Research paper thumbnail of Study of dynamic relationships between financial

Research paper thumbnail of Applred Mathematrcs and Computatron mmrmm

Research paper thumbnail of ¢ Sc| enceD| rect M

Research paper thumbnail of The vievvs. opinions and/or findings contained inthis re on are those of the author (s) and should not be construed as

Research paper thumbnail of Commun Nonlinear Sci Numer Simulat

Research paper thumbnail of Applied Multivariate Analysis

Research paper thumbnail of M-estimator-based robust estimation of the number of components of a superimposed sinusoidal signal model

ABSTRACT In this paper, we consider the problem of estimating the number of components of a super... more ABSTRACT In this paper, we consider the problem of estimating the number of components of a superimposed nonlinear sinusoids model of a signal in the presence of additive noise. We propose and provide a detailed empirical comparison of robust methods for estimation of the number of components. The proposed methods, which are robust modifications of the commonly used information theoretic criteria, are based on various M-estimator approaches and are robust with respect to outliers present in the data and heavy-tailed noise. The proposed methods are compared with the usual non-robust methods through extensive simulations under varied model scenarios. We also present real signal analysis of two speech signals to show the usefulness of the proposed methodology.

Research paper thumbnail of Identifying patterns of socio-economic development using self-organizing maps

Research paper thumbnail of On parameter estimation of two dimensional chirp signals

Research paper thumbnail of Sequential estimation of two dimensional sinusoidal models

Estimating the unknown parameters of a two-dimensional (2-D) sinusoidal signal is an important an... more Estimating the unknown parameters of a two-dimensional (2-D) sinusoidal signal is an important and a difficult problem. In this paper, we propose a simple sequential procedure for estimating the unknown frequencies and amplitudes of the 2-D sinusoidal components when the ...

Research paper thumbnail of Integration of Financial Markets in India: An Empirical Investigation

Research paper thumbnail of A wavelet filtering based estimation of output gap

Research paper thumbnail of Forecasting business cycle movements using wavelet filtering and neural networks

Research paper thumbnail of Detecting the number of signals for an undamped exponential model using cross-validation approach

Research paper thumbnail of Genetic algorithm and M-estimator based robust sequential estimation of parameters of nonlinear sinusoidal signals

Research paper thumbnail of Cellular, molecular and immunological mechanisms in the pathophysiology of vein graft intimal hyperplasia

Immunology and cell biology, 2006

Coronary artery disease, leading to myocardial infarction and ischaemia, affects millions of pers... more Coronary artery disease, leading to myocardial infarction and ischaemia, affects millions of persons and is one of the leading causes of morbidity and mortality worldwide. Invasive techniques such as coronary artery bypass grafting are used to alleviate the sequelae of arterial occlusion. Unfortunately, restenosis or occlusion of the grafted conduit occurs over a time frame of months to years with a gradual reduction in patency, especially in vein grafts. The events leading to intimal hyperplasia (IH) formation involve numerous cellular and molecular components. Various cellular elements of the vessel wall are involved as are leucocyte-endothelial interactions that trigger the coagulation cascade leading to localized thrombus formation. Subsequent phenotypic modification of the medial smooth muscle cells and their intimal migration is the basis of the lesion formation that is thought to be propagated by an immune-mediated reaction. Despite intense scrutiny, the pathophysiology of IH...

Research paper thumbnail of Temporal PTEN inactivation causes proliferation of saphenous vein smooth muscle cells of human CABG conduits

Journal of cellular and molecular medicine, 2009

Internal mammary artery (IMA) coronary artery bypass grafts (CABG) are remarkably resistant to in... more Internal mammary artery (IMA) coronary artery bypass grafts (CABG) are remarkably resistant to intimal hyperplasia (IH) as compared to saphenous vein (SV) grafts following aorto-coronary anastomosis. The reason behind this puzzling difference still remains an enigma. In this study, we examined the effects of IGF-1 stimulation on the PI3K-AKT/PKB pathway mediating proliferation of smooth muscle cells (SMCs) of IMA and SV origin and the specific contribution of phosphatase and tensin homologue (PTEN) in regulating the IGF-1-PI3K-AKT/PKB axis under these conditions. Mitogenic activation with IGF-1, time-dependently stimulated the phosphorylation of PI3K and AKT/PKB in the SV SMCs to a much greater extent than the IMA. Conversely, PTEN was found to be significantly more active in IMA SMCs. Transient overexpression of PTEN in SMCs of SV and IMA inhibited AKT/PKB activity and upstream of AKT/PKB, caused a reduction of IGF-1 receptors. Downstream, PTEN overexpression in SV SMCs induced the...

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