Polar codes, that have been recently introduced by Arikan, are one of the first codes that achieved the capacity for vast numerous channels and they also have low complexity in symmetric memoryless channels. Polar codes are constructed based on a phenomenon called channel polarization. This paper discusses relay channel polarization in order to achieve the capacity and show that if inputs of tw...

One of the most important conflicts that shaft spillways have to deal with is vortex formation. This phenomenon leads to some unfavorable effects such as vibration in the body of structures, air entrainment and reduced overflow capacity of the spillway. Among all solutions for disrupted vortex formation, an innovative one called circular piano-key spillway, based upon piano key weir principles ...

In dry lands, semi-circular bund has been considered as a management practice used to restore the ecological revival in terms of vegetation enrichment and soil amelioration. This study was conducted to investigate the effects of semi-circular bunds on vegetation cover and some soil properties in Koteh rangeland, Sistan and Baloochestan province, Iran (2014). Adjacent to the semi-circular bund a...

in this paper, analysis of fluid flow and heat transfer over the bank of tubes is considered. k-ω sst model is applied for simulation of turbulent flow. in this paper, the improvement of efficiency of a bundle of circular tubes by changing the shape of the cross section of one row of the pipes to the elliptical cross section as an innovative plan is considered. as know, friction factor in turbu...

In this study, the flow boiling heat transfer and pressure drop characteristics of refrigerant R134a in micro-channels were experimentally investigated. The tests performed circular horizontal with inner diameters 0.5 mm 1 a heating length 300 mm. mass velocities varied from 500 kg/m2s to 2500 kg/m2s, fluxes 15 kW/m2 147 kW/m2. coefficient (HTC) frictional (FPD) measured discussed detail. Accor...

Zirconia ultrafiltration membranes are widely developed and used for past several years. But the conventional sol-gel methods of zirconia membrane preparation involve many steps. In the present study an attempt was made to develop defect free zirconia ultrafiltration (UF) membrane in single step coating of zirconia nanopowder suspension by slip casting method over multichannel ceramic support. ...

background: stereotactic radiosurgery is an important clinical tool for the treatment of small lesions in the brain, including benign conditions, malignant and localized metastatic tumors. a dosimetry study was performed for elekta ‘synergy s ’ as a dedicated stereotactic radiosurgery unit, capable of generating circular radiation fields with diameters of 1-5 cm at isocentre using the beam/egs4...

We consider blind estimation of the carrier frequency o set of a linearly modulated non-circular transmission through an unknown frequency selective channel. A frequency estimator is developed based on the unique conjugate cyclic frequency of the received signal that equals twice the frequency o set. We establish consistency and asymptotic normality of the frequency estimator, and calculate its...

Article history: Received 15 October 2013 Received in revised form 19 February 2014 Accepted 20 February 2014 Available online 19 March 2014

This paper presents results of experiments using a variety of antennas inside several buildings. Path loss models are presented for the 1.3 GHz and 4.0 GHz bands, and indicate little difference in indoor path loss throughout the low-microwave region. Results show that line-of-sight (LOS) channels offer significantly more cross-polarization discrimination than obstructed (OBS) channels. A profou...