Informatics Publishing Limited

M. Akbari ¹, G. Zare Fatin ¹, R. Asvadi ¹

Affiliations
1 Department of Computer Engineering and Information Technology, University of Mohaghegh Ardabili, Ardabil, IR

Abstract

In this letter, we analyze the performance of two improved Sum-Product (SP) based decoding algorithms for LDPC codes. In order to improve the decoding operation and fast convergence decoder At  First,  Using Averaging and using bits in the wrong equations for improve the bit node update And then by using a genetic algorithm. We corrected value bits decoding mistake is detected and value soft decision is less than 2. The decoding performance of GA-SP algorithm is superior to original SP algorithms by about 2 dB and is very close to the performance of ML decoding for (2640, 1320) Tanner LDPC code.

Keywords

Iterative Decoding, Low-Density Parity-Check (LDPC) Codes, Minimum Bit Error Rate, Sum Product Algorithm (SPA), Sum-Product Genetic Decoding (SPGD) Algorithm.

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M. Vaghefi ¹, M. Shakerdargah ², A. R. Fiouz ¹, M. Akbari ³

Affiliations
1 Department of Civil Engineering, Persian Gulf University, Bushehr, IR
2 Civil Engineering Department, Islamic Azad University, Bushehr, IR
3 Civil Engineering Department, Persian Gulf University, Bushehr, IR

Abstract

In this paper, flow pattern around an unsubmerged T-shaped spur dike in a 45 degree position, and located in a 90 degree bend with different Froude Numbers has been studied using Flow-3D and has been compared with experimental results. To determine the effect of Froude Number on flow pattern, flow pattern in longitudinal, cross, and plan sections have been studied.

Keywords

90 Degree Bend, Flow Pattern, T-Shaped Spur Dike, Flow-3D, Froude Number.

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M. Vaghefi ¹, M. Akbari ¹, A. R. Fiouz ¹

Affiliations
1 Department of Civil Engineering, Persian Gulf University, Bushehr, IR

Abstract

Because of the great importance of shear stress parameter in river sediment transport mechanisms, different methods for calculating them are presented. This paper has used Depth-Averaged Method to study and analyse shear stress distribution near the bed in a 180 degree sharp bend. The results suggested that the maximum dimensionless shear stress near the bed occurs at the beginning of the bend, near the inner wall and in the 40 degree cross section.

Keywords

180 Degree Bend, Sharp Bend, Bed Shear Stress, Depth-Averaged Method, Vectrino.

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M. Vaghefi ¹, M. Shakerdargah ², M. Akbari ¹

Affiliations
1 Department of Civil Engineering, Persian Gulf University, Bushehr, IR
2 Department of Civil Engineering, Islamic Azad University, Bushehr, IR

Abstract

Spur dike is one of the hydraulic structures used in rivers to protect river banks. In this paper, flow pattern around a T-shaped spur dike which is located in a 90° bend and different amounts of submersion has been studied using Flow-3D. Numerical results have been compared with experimental results and have been analysed.

Keywords

Submerged T-Shaped Spur Dike, Three Dimensional Velocity, Flow Pattern, 90 Degree Bend, Flow-3D.

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