Search

Your search keyword '"Ghobadi, C."' showing total 161 results
Start Over Author "Ghobadi, C."
161 results on '"Ghobadi, C."'

1. Tracking Performance of Incremental LMS Algorithm over Adaptive Distributed Sensor Networks

Author

Mostafapour, Ehsan, Ghobadi, C., Nourinia, Javad, and Amirani, M. Chehel

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Information Theory
Abstract

In this paper we focus on the tracking performance of incremental adaptive LMS algorithm in an adaptive network. For this reason we consider the unknown weight vector to be a time varying sequence. First we analyze the performance of network in tracking a time varying weight vector and then we explain the estimation of Rayleigh fading channel through a random walk model. Closed-form relations are derived for mean square error (MSE), mean square deviation (MSD) and excess mean square error (EMSE)of analyzed network in tracking Rayleigh fading channel and random walk model. Comparison between theoretical and simulation results shows a perfect match and verifies performed calculations.

Published
2021
Full Text
View/download PDF

7. Electromagnetically coupled band-notched elliptical monopole antenna for UWB applications

Author

Eshtiaghi, R., Nourinia, J., and Ghobadi, C.

Subjects
Electric waves -- Analysis, Electromagnetic radiation -- Analysis, Electromagnetic waves -- Analysis, Ultra wideband technology -- Usage, Mobile communication systems -- Analysis, Wireless communication systems -- Analysis, Wireless technology, Business, Computers, Electronics, Electronics and electrical industries
Published
2010

15. Effect of Substrate Scaling on Microstrip Patch Antenna Performance

Author

Esmaeilkhah, A., Ghobadi, C., Nourinia, J., Majidzadeh, M., Esmaeilkhah, A., Ghobadi, C., Nourinia, J., and Majidzadeh, M.

Abstract

The Maxwell field equations (MFEs), as ecumenical model of electromagnetic phenomena, are scale-invariant under Lorentz Transformation (LT). To apply LT, some considerations are required which are not all practically available or technologically attainable; hence, the scale-invariant feature may not be reached effectively. Paving the way to focus on this issue, the effect of substrate thickness scaling as an uncontrollable parameter, is explored on eight identical patch antennas with different substrate thicknesses. In this way, the resonant frequency and complex value of return loss are measured. The effect of manufacturing tolerances of dielectric thickness on resonant frequency deviation and return loss magnitude are carefully studied, too. Also the unwanted distortive effect of selected electrical connection, say as a female SMA connector, is investigated at higher frequencies. The obtained results are comparatively analyzed which confirm the practical bottlenecks in meeting the antenna parameters scaling.

Published
2018

19. Channel Fading Effect Analysis on Diffusion Cooperation Strategies over Adaptive Networks.

Author

Jie Yang, Mostafapour, Ehsan, Aminfar, Amir, Jie Wang, Hao Huang, Akhbari, Afsaneh, Ghobadi, C., and Guan Gui

Subjects
RADIO transmitter fading, ADAPTIVE computing systems, WIRELESS communications, RICIAN channels, WIRELESS channels, RAYLEIGH fading channels, CHANNEL estimation, WIRELESS cooperative communication
Abstract

In this paper, we investigate the performance of the diffusion adaptation strategies for parameter estimation in wireless adaptive networks, where the nodes exchange information over noisy and fading wireless channels. This paper shows the differences between the effect of Rayleigh and Rician fading over wireless adaptive networks and proves that the Rician fading is a more practical model in such kinds of networks. Simulation results imply that the effect of Rayleigh fading is more degrading for the estimation process than Rician fading. Also, the simulation results show the performance of adapt then combine (ATC) diffusion algorithm is better than the combine then adapt (CTA) algorithm by merely considering noise in wireless channels. While the performance of CTA prevails ATC over the wireless adaptive network in the presence of noise plus channel fading. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

22. Modified-release hydrocortisone to provide circadian cortisol profiles \ud \ud

Author

Debono, M., Ghobadi, C., Rostami-Hodjegan, A., Huatan, H., Campbell, M.J., Newell-Price, J., Darzy, K., Merke, D.P., Arlt, W., and Ross, R.J.

Abstract

Context: Cortisol has a distinct circadian rhythm regulated by the brain's central pacemaker. Loss of this rhythm is associated with metabolic abnormalities, fatigue, and poor quality of life. Conventional glucocorticoid replacement cannot replicate this rhythm.\ud Objectives: Our objectives were to define key variables of physiological cortisol rhythm, and by pharmacokinetic modeling test whether modified-release hydrocortisone (MR-HC) can provide circadian cortisol profiles.\ud \ud Setting: The study was performed at a Clinical Research Facility.\ud \ud Design and Methods: Using data from a cross-sectional study in healthy reference subjects (n = 33), we defined parameters for the cortisol rhythm. We then tested MR-HC against immediate-release hydrocortisone in healthy volunteers (n = 28) in an open-label, randomized, single-dose, cross-over study. We compared profiles with physiological cortisol levels, and modeled an optimal treatment regimen.\ud \ud Results: The key variables in the physiological cortisol profile included: peak 15.5 mu g/dl (95% reference range 11.7-20.6), acrophase 0832 h(95% confidence interval 0759-0905), nadir less than 2 mu g/dl (95% reference range 1.5-2.5), time of nadir 0018 h (95% confidence interval 2339-0058), and quiescent phase (below the mesor) 1943-0531 h. MR-HC 15 mg demonstrated delayed and sustained release with a mean (SEM) maximum observed concentration of 16.6 (1.4) mu g/dl at 7.41 (0.57) h after drug. Bioavailability of MR-HC 5, 10, and 15 mg was 100, 79, and 86% that of immediate-release hydrocortisone. Modeling suggested that MR-HC 15-20 mg at 2300 h and 10 mg at 0700 h could reproduce physiological cortisol levels.\ud \ud Conclusion: By defining circadian rhythms and using modern formulation technology, it is possible to allow a more physiological circadian replacement of cortisol. (J Clin Endocrinol Metab 94: 1548-1554, 2009)\ud

Published
2009

23. A Band-Notched Square Monopole Antenna designed for Bandwidth Enhancement in UWB Applications.

Author

Azarm, B., Ghobadi, C., Nourinia, J., Abbasilayegh, M., and Karamirad, M.

Subjects
*MONOPOLE antennas, *ULTRA-wideband devices, *ANTENNAS (Electronics), *BANDWIDTHS, *ELECTROMAGNETIC devices
Abstract

In this letter, a square monopole antenna has been designed for ultrawideband (UWB) applications having variable notch frequency characteristic. The proposed antenna consists of the small square radiating patch with two rectangular slots, which provides a wide usable fractional bandwidth from 3.1 to 14.4 GHz. The proposed antenna is simple and has a very small size of 10x15 mm². The bandwidth of the proposed antenna is wider than that of the antenna that has already been introduced in references. Experimental results show that the proposed antenna could be a good candidate for ultrawideband (UWB) applications. [ABSTRACT FROM AUTHOR]

Published
2017

24. Paclobutrazol application enhances antioxidant enzyme activities in pomegranate plants affected by cold stress.

Author

Moradi, S., Baninasab, B., Gholami, M., and Ghobadi, C.

Subjects
POMEGRANATE, PACLOBUTRAZOL, EFFECT of cold on plants
Abstract

Paclobutrazol (PBZ) is a member of the triazole plant growth inhibitor group that is responsible for inducing tolerance to a number of biotic and abiotic stresses. An experiment was, therefore, conducted to test whether PBZ application at various concentrations (0, 25, 50, or 75 mg L−1) through foliar spray or soil drench would protect pomegranate (Punica granatum) seedlings cv. Robab, subjected to freezing at −3°C for 7 hours. PBZ improved the growth rate of pomegranate seedlings subjected to freezing stress and increased relative leaf chlorophyll content, chlorophyll fluorescence ratio, relative water content, soluble carbohydrate content, and enzyme activity of ascorbate peroxidase and guaiacol peroxidase compared with the control at the end of experiment. PBZ ameliorated the injury caused by freezing stress by inhibiting increases in proline content and leaf electrolyte leakage, which suggested that PBZ ameliorated the negative effect of freezing stress. The best protection was obtained from plants treated with PBZ at 50 or 75 mg L−1. The most evaluated parameters were not affected by PBZ application method. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

27. Antenna Design for Ultra Wideband Application Using Stacked Multiresonator Patches

Author

Nourinia, J, Zehforoosh, Y, Ghobadi, C, Nourinia, J, Zehforoosh, Y, and Ghobadi, C

Abstract

As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .This paper presents some of the work carried out within ULTRAWAVES in the area of antenna design and analysis. Two antennas have been designed, optimized and simulated using Stacked Multiresonator patches. In addition results and conclusions are presented

Published
2007

Catalog

Books, media, physical & digital resources
See catalog results