Coding Advantage Optimization of Space-time-frequency Block Codes

Vahid Momenaei Kermani,Hossein Momenaee Kermani,Alireza Morsali 한국통신학회 2020 Journal of communications and networks Vol.22 No.2

In this article, we study the coding advantage of spacetime-frequency block codes (STFBCs). Since in MIMO-OFDMcoding there is the potential of exploiting space, time and frequencydiversities and as the frequency tones of OFDM modulation arerelatively substantial, the intricate structure of STFBCs makes italmost impossible to optimize the parameters of the code as thenumber of symbols increases in each block. Consequently, we investigatehow to optimize the code parameters independently toreduce the computational complexity. Furthermore, code permutationis an important part of the STFBCs. However, due to elaboratestructure of the STFBCs, it is very hard to calculate the optimumpermutation. Therefore, we put forth a technique to decompose thecoding advantage of the STFBCs. Using this technique, the permutationparameter can be easily introduced and optimized for STFBCs. We then design a novel STFBC based on any given STBC andapply the proposed scheme on the proposed STFBC to illustratethe application of this technique by designing the optimum permutationfor the code. Simulation results confirm that the proposedSTFBC outperforms the best existing STFBCs in the literature.

Synthesis, characterization and bactericidal property of chitosan-graft-polyaniline/ montmorillonite/ZnO nanocomposite

Alireza Samzadeh-Kermani,Somayeh Miri 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.6

We synthesized the nanocomposite of chitosan-graft-polyaniline/montmorillonite/zinc oxide (CTS-g-PANi/ MMT/ZnO). ZnO nanoparticles (NPs) were successfully synthesized from ZnO powder in the Cts/MMT matrix, using traditional method. CTS-g-PANi co-polymer was synthesized in the presence of ammonium peroxydisulfate (APS). The CTS-g-PANi and MMT were used as the natural polymeric stabilizer and the solid support, respectively. The morphology and the particle size of ZnO NPs and synthesized nanocomposite were investigated by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). According to the XRD results, the nanoparticle size was found to be in the range of 22-35 nm. SEM images showed the hexagonal shape of ZnO NPs, which is suitable for the evaluation of antibacterial activity. Finally, the bactericidal property of prepared nanocomposites was also evaluated against the bacteria of Gram positive Staphylococcus aureus (Staph.) and Gram negative Escherichia coli (E. coli), using the paper disc diffusion method.

Visible-light-induced nitrogen photofixation ability of g-C3N4 nanosheets decorated with MgO nanoparticles

Elham Vesali-Kermani,Aziz Habibi-Yangjeh,Srabanti Ghosh 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.84 No.-

Nitrogenfixation is a natural or artificial process, in which molecular nitrogen is combined with otherelements to form more-reactive compounds containing nitrogen elements. In this study, graphitic carbonnitride nanosheets were combined with nanoparticles of MgO to fabricate an efficient binary visiblelight-induced photocatalysts (abbreviated as NCN/MgO), and they were applied for the photofixation ofnitrogen gas. The synthesized photocatalysts were characterized to investigate the morphology, phasestructure, optical, and textural properties. The results displayed that the NCN/MgO (10%) nanocompositehas considerable performance in the nitrogen photofixation reaction compared with the pristine CN andNCN, which is 10.8 and 2.8 times, respectively. The stability of the optimum sample, as a vitalcharacteristic of photocatalyst, was examined in three runs. Also, the effect of MgO loading, calcinationtemperature, solvent, electron scavenger, pH, and absence of N2 in solution upon the NH4+ productionrate was examined. Finally, an anticipated mechanism was proposed for the meaningful nitrogenphotofixation enhancement.

A Data Mining Approach for a Dynamic Development of an Ontology-Based Statistical Information System

Mohamed Hachem Kermani,Zizette Boufaida,Amel Lina Bensabbane,Besma Bourezg 한국과학기술정보연구원 2023 Journal of Information Science Theory and Practice Vol.11 No.2

This paper presents a dynamic development of an ontology-based statistical information system supporting the collection, storage, processing, analysis, and the presentation of statistical knowledge at the national scale. To accomplish this, we propose a data mining technique to dynamically collect data relating to citizens from publicly available data sources; the collected data will then be structured, classified, categorized, and integrated into an ontology. Moreover, an intelligent platform is proposed in order to generate quantitative and qualitative statistical information based on the knowledge stored in the ontology. The main aims of our proposed system are to digitize administrative tasks and to provide reliable statistical information to governmental, economic, and social actors. The authorities will use the ontology-based statistical information system for strategic decision-making as it easily collects, produces, analyzes, and provides both quantitative and qualitative knowledge that will help to improve the administration and management of national political, social, and economic life.

Conjunction of 2D and 3D Modified Flow Solvers for Simulating Spatio-Temporal Wind Induced Hydrodynamics in the Caspian Sea

Mohammad Zounemat-Kermani,Saeed-Reza Sabbagh-Yazdi 한국해양과학기술원 2010 Ocean science journal Vol.45 No.2

The main objective of this study is the simulation of flow dynamics in the deep parts of the Caspian Sea, in which the southern and middle deep regions are surrounded by considerable areas of shallow zones. To simulate spatio-temporal wind induced hydrodynamics in deep waters, a conjunctive numerical model consisting of a 2D depth average model and a 3D pseudo compressible model is proposed. The 2D model is applied to determine time dependent free surface oscillations as well as the surface velocity patterns and is conjunct to the 3D flow solver for computing three-dimensional velocity and pressure fields which coverage to steady state for the top boundary condition. The modified 2D and 3D sets of equations are conjunct considering interface shear stresses. Both sets of 2D and 3D equations are solved on unstructured triangular and tetrahedral meshes using the Galerkin Finite Volume Method. The conjunctive model is utilized to investigate the deep currents affected by wind, Coriolis forces and the river inflow conditions of the Caspian Sea. In this study, the simulation of flow field due to major winds as well as transient winds in the Caspian Sea during a period of 6 hours in the winter season has been conducted and the numerical results for water surface level are then compared to the 2D numerical results.

Free vibration analysis of multi-directional functionally graded circular and annular plates

Iman Davoodi Kermani,Mostafa Ghayour,Hamid Reza Mirdamadi 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

This paper addresses the free vibration of multi-directional functionally graded circular and annular plates using a semianalytical/numerical method, called state space-based differential quadrature method. Three-dimensional elasticity equations are derived for multi-directional functionally graded plates and a solution is given by the semi-analytical/numerical method. This method gives an analytical solution along the thickness direction, using a state space method and a numerical solution using differential quadrature method. Some numerical examples are presented to show the accuracy and convergence of the method. The most of simulations of the present study have been validated by the existing literature. The non-dimensional frequencies and corresponding displacements mode shapes are obtained. Then the influences of thickness ratio and graded indexes are demonstrated on the non-dimensional natural frequencies.

EVALUATING THE HYDRAULIC EFFICIENCY IN ARTIFICIAL WETLANDS

YAZDANDOOST FARHAD,KERMANI MOHAMMAD ZOUNEMAT 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Proton exchange membrane fuel cells performance enhancement using bipolar channel indentation

Mohammad Dehsara,Mohammad J. Kermani 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.1

The influence of bipolar channel indentation on the performance enhancement of proton exchange membrane (PEM) fuel cells is studiedusing three-dimensional computation of a whole single cell. It is assumed that the cell operates under a fixed dry condition of 80°C, 1atm, and inlets’ relative humidity of 10%. Hence the sole influence of channel-bed shapes on the cell performance was considered. Threestraight channels with different bed shapes were considered, namely, flat and indented (including semicircular and wavy) channel-beds. Itis observed that the channel-bed shapes directly influence the fluid mechanics of the flow field within the channels, such as the magnitudeand direction of the velocity vectors, pressure variations along the channels, and the consumption rates of oxygen and hydrogenwithin the catalyst layer. The results reveal that gas flow channel indentations in the anode and cathode sides enhance the net transport ofreacting species through the porous layers toward the catalyst layer. The improvement of the cell due to channel indentation is observedto be in the range 18-22%.

Applying the ball-spine algorithm to the design of blunt leading edge airfoils for axial flow compressors

Ali Madadi,Mohammad Jafar Kermani,Mahdi Nili-Ahmadabadi 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.11

An inverse design algorithm, called the ball-spine (BS) algorithm, is developed for the design of axial flow compressor blades. Thisalgorithm has been previously applied to the design of 2D sharp leading edge airfoils. In the present study, the BS algorithm is extendedto the design of blunt leading edge compressor blade sections. The algorithm receives a target pressure loading and an initial guess for itsgeometry. Through the design procedure, the geometry is evolved until the target pressure is achieved. The accuracy of the method isassessed against two airfoils, namely, NACA65-410 (with the initial guess for geometry as a flat-plate-airfoil) and NACA65-610 (withthe initial guess for geometry as NACA65-410). The method is shown to be efficient and accurate, and can capture the target geometry inapproximately 50 evolutions. As an application, a new airfoil with 5% more lift than NACA65-610 is designed, for which NACA65-610geometry is used as the initial guess.

Interference of oxygen during the solution combustion synthesis process of ZnO particles: Experimental and data modeling approaches

E. Garmroudi Nezhad,F. Kermani,Z. Mollaei,M. Mashreghi,J. Vahdati Khakhi,S. Mollazadeh 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.107 No.-

In the present study, the ratio of reducing to oxidizing (F/O) elements as an indicator for maximumoxygen interference during the solution combustion synthesis (SCS) process of ZnO particles was determinedusing simple mathematical calculations. The obtained result was called special point (S.P). Tointerpret the role of S.P in the SCS reactions, ZnO particles were synthesized in the presence of citric acid,hexamine, hydrazine, and urea with various F/O values (0.75, 1, 1.25). The correlations between the S.P,physicochemical properties of the synthesized ZnO powders, and density functional theory (DFT) predictionswere investigated. X-ray diffraction results, band-gap values, oxygen vacancy data, DFT results, andS.P points demonstrated the direct relation of these parameters. According to the S.P idea, it can beaffirmed that the structural defects, particle size, optical band-gap (Eg = 3.06), the color of the products,the magnetic properties (0.2 emu/g), and the antibacterial inhibitory (15.625 mg/mL) of the synthesizedparticles were controlled via the interference of O2 during the synthesis process. In fact, the S.P investigationwas suggested that the reaction rate of the combustion synthesis process could regulate the propertiesof ZnO particles.