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Your search keyword '"MOMENI, HAMID REZA"' showing total 17 results
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17 results on '"MOMENI, HAMID REZA"'

3. A Recursive Delay Estimation Algorithm for Linear Multivariable Systems with Time-varying Delays

Author

Shafikhani, Iman, Karimi, Hazhar Sufi, Mohammadian, Mohammad, Ramezani, Amin, and Momeni, Hamid Reza

Subjects
Electrical Engineering and Systems Science - Systems and Control, Electrical Engineering and Systems Science - Signal Processing
Abstract

Time delay estimation plays a critical role in control, stabilization and state estimation of many practical system with time delay. In this paper, we propose a method to estimate delay for discrete time linear multiple-input multiple-output systems with time-varying input delays. This method is purposefully given for situations where only a limited amount of information is available for the system. Although, this approach is primarily developed in a deterministic framework, it can also be applied to noisy data under special circumstances. In addition, switched linear autoregressive models with exogenous inputs are introduced as possible applications of the presented algorithm provided that the switching frequencies are small. Finally, effectiveness of the algorithm is illustrated by two numerical examples.

Published
2021

10. Comparing the acute and chronic effects of metformin and antioxidant protective effects of N-acetyl cysteine on memory retrieval and oxidative stress in rats with Alzheimer’s disease.

Author

Darbandi, Niloufar, Moghadasi, Samira, Momeni, Hamid Reza, and Ramezani, Matin

Abstract

It has been suggested that oxidative stress plays an important role in neural degeneration and Alzheimer's disease. Some studies have shown that metformin has some beneficial effects on the brain and reduces oxidative stress, while others reveal that metformin increases oxidative stress in diabetic patients. In this study acute and chronic effects of metformin and antioxidant protective effects of N-acetyl cysteine in Alzheimeric rats were investigated. Animals were divided into seven groups (n=8): Control, STZ, STZ + metformin (one, three and eleven weeks), STZ+ metformin (eleven weeks) +N-acetyl cysteine (eleven weeks) and N-acetyl cysteine (eleven weeks). ICV injections of saline (1μl/rat) or STZ (3mg/kg) and IP injections of Saline (1ml/kg), metformin (200mg/kg) and/or N-acetyl cysteine (100mg/kg) were done. Memory retrieval, CA1 neurons density and serums oxidative stress were investigated. STZ injections reduced memory retention, intact neurons and increased serum oxidative stress compared to the control (p<0/001). Metformin injection for one and three weeks (but not eleven weeks) improved the effects of STZ (p<0/001). Administration of N-acetylcysteine with metformin (eleven weeks) improved STZ bad effects (p<0/001). It seems that acute and chronic consumption of metformin have different effects on memory retrieval, CA1 neurons and serum oxidative stress factors in AD rats. [ABSTRACT FROM AUTHOR]

Published
2023
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12. The effect of Eggplant peel extract addition (Solanummelongena) on Farahani ram sperm after oxidative stress (freeze-thawing).

Author

Khodadadi, Hamidreza, Khodaei-Motlagh, Mahdi, Kazemi-Bonchenari, Mehdi, and Momeni, Hamid Reza

Subjects
RAMS, OXIDATIVE stress, PLANT extracts, EGGPLANT, CONTROL groups, ARTIFICIAL insemination
Abstract

The aim of this study was to evaluate the effect of Eggplant peel extract on post-thawed ram sperm quality in a Tris-based extender. Semen was collected by artificial insemination vagina. Samples were pooled to prevent individual effects. Then ram semen samples were obtained, extended with Tris-based extender and supplemented with 0%, 2%, 4%, 6%, and 8% Eggplant peel extract. Later, samples were frozen by liquid nitrogen in the straw (0.25 ml). After thawing, sperm motility, viability (Nigrosine-eosin staining), membrane integrity with Hypo osmotic (Host) and morphology abnormality (Hancock test) were evaluated. Results showed that the value of 2% (62.4) of the Eggplant extract peel had a significant effect on sperm motility and membrane integrity after thawing. Also, the 2% and 4% of Eggplant peel extract groups had the most significant motility as compared to the control group and, the least motility was regarded as the most concentration of 8% of the Eggplant peel extract as compared to the control group. Thus, adding 2% and 4% of the Eggplant peel extract to Tris-based extender preserved Farahani ram sperm after thawing. [ABSTRACT FROM AUTHOR]

Published
2023
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16. A bayesian framework for large-scale identification of nonlinear hybrid systems

Author

Madary, Ahmad, Momeni, Hamid Reza, Abate, Alessandro, and Larsen, Kim G.

Subjects
Nonlinear hybrid systems, Switched nonlinear arx models, Bayesian inference, Occam's razor principle, System identification, Large data sets
Abstract

In this paper, a two-level Bayesian framework is proposedfor the identification of nonlinear hybrid systems fromlarge data sets by embedding it in a four-stage procedure.At the first stage, feature vector selection techniques areused to generate a reduced-size set from the given trainingdata set. The resulting data set then is used to identifythe hybrid system using a Bayesian method, where theobjective is to assign each data point to a correspondingsub-mode of the hybrid model. At the next (third) stage,this data assignment is used to train a Bayesian classifierto separate the original data set and determine thecorresponding sub-mode for all the original data points.Finally, once every data point is assigned to a sub-mode, aBayesian estimator is used to estimate a regressor for eachsub-system independently. This Bayesian approach finds acompromise between model complexity and accuracy. Theproposed method tested on three case studies. First, theidentification based on the full data set is compared withthat based on the reduced data set, over a nonlinear hybridsystem. Then, the proposed approach is compared with anexisting method from the literature, with improvedperformance over estimation error and mode assignment.Finally, the performance of the new method is tested byidentifying a complex hybrid model.

Published
2021

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