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Multiuser Detection for MIMO-OFDM system in Underwater Communication Using a Hybrid Bionic Binary Spotted Hyena Optimizer

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Journal of Bionic Engineering 2021年第2期18卷 462-472页

作者： md rizwan khan Bikramaditya Das Department of Electronics&Telecommunication Engineering VSS University of TechnologyBurla-768018OdishaIndia

Multi Access Interference (MAI) is the main source limiting the capacity and quality of the Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system which fulfills the demand of high-speed transmission rate and high quality of service for future underwater acoustic (UWA) communication. Multi User Detection (MUD) is needed to overcome the performance degradation caused by MAI. In this research, both local and global optimal solutions are obtained in Bionic Binary Spotted Hyena Optimizer (BBSHO) algorithm using the Position Coordinate Vectors (PCVs) of the social behavior of spotted hyenas to achieve MUD. Further, Extremal Optimization (EO) is introduced in BBSHO algorithm to improve the local search ability within the search space. Hence, a hybrid BBSHO algorithm is proposed for achieving MUD at the receiver of the MIMO-OFDM system whose transceiver model in underwater is implemented using BELLHOP simulation system. By MATLAB simulation, it is shown that the Bit Error Rate (BER) performance of the proposed hybrid algorithm outperforms with best optimal solution within the search space towards MUD for Interference to Noise Ratio (INR) at 10 dB, 20 dB, and 40 dB over conventional detectors and metaheuristic approaches such as Binary Spotted Hyena Optimizer (BSHO), Binary Particle Swarm Optimization (BPSO) in the UWA network.

关键词： Underwater Acoustic(UWA) Orthogonal Frequency Division Multiplexing(OFDM) Multiuser Detection(MUD) Multi-Access Interference(MAI) Bionic Binary Spotted Hyena Optimizer(BBSHO) Extremal Optimization(EO)

Plasticity of leaf morphology of Bruguiera sexangula to salinity zones in Bangladesh's Sundarbans

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Journal of Forestry Research 2022年第6期33卷 1857-1866页

作者： md.Salim Azad Abdus Subhan Mollick Rawnak Jahan khan Ranon md.Nabiul Islam khan md.Kamruzzaman Forestry and Wood Technology Discipline Khulna UniversityKhulna 9208Bangladesh Graduate School of Agriculture Kyoto UniversityKyoto 606-8501Japan

Bruguiera sexangula(Lour.)Poir is an exclusive evergreen mangrove species to the Sundarbans of *** grows well in moderate saline zones with full *** study presents leaf morphological plasticity in *** to saline *** were sampled from different saline zones and various morphological traits were *** results exposed a wide deviations of leaf size parameters:leaf length varied 6.6–17.3 cm;width 2.7–7.8 cm;upper quarter width 2.2–6.5 cm;down quarter width 2.5–7.3 cm;and petiole length 0.17–1.43 *** length was significantly larger in fresh water than in other salinity zones,whereas,leaf width,upper and lower leaf quarters were significantly larger in medium saline *** shape parameters showed a large variation among saline *** base angle was significantly larger in both medium and strong salinity *** angle was significantly greater in medium salinity *** perimeter was significantly larger in fresh water but leaf area was significantly bigger in medium saline *** index and specific leaf area were maximum in moderate saline *** index was the highest in moderate saline for almost all the parameters *** ordination(PCA)showed clusters of leaf samples although there were some overlap among them which suggested a salt-stress relationship among salinity *** results indicate that *** had a plasticity strategy on leaf morphological parameters to salinity in the *** study will provide basic information of leaf plasticity of this species among saline zones which will help for site selection of coastal planting and will also provide information for policy makers to take necessary steps for its conservation.

关键词： Salinity stress Phenotypic variation Plasticity index Specific leaf area PCA

A New Algorithm for a Condenser Design for Large-Scale Nuclear Power Plants in Tropical Region

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Journal of Thermal Science 2020年第5期29卷 1370-1389页

作者： khan Abid Hossain ISLAM md.Shafiqul Department of Industrial and Production Engineering Jashore University of Science and TechnologyJashore 7408Bangladesh Department of Nuclear Engineering University of DhakaDhaka 1000Bangladesh

This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical *** this,the condenser pressure was considered in the range of 7.5-15 kPa while its tube inner diameter was taken as 28 mm with 1 mm tube wall *** longitudinal and transverse condensers with multiple shell tanks and varied shell tank lengths from 8-14 m have been considered in this *** different tertiary coolant temperature rises were chosen as 4°C,8°C and 12°C by considering tropical region average reservoir water temperature range of 28°C to 32°C during *** of tertiary coolant was kept within 0.75-1.5 m/s to ensure sufficient turbulence to avoid erosion-corrosion of the *** simulation has been employed to obtain tube-side pressure drop and convection heat transfer coefficient directly from tertiary coolant inlet velocity using κ-ω turbulent flow model.A new iterative“Velocity-search algorithm”has been developed that focuses on finding the correct tertiary coolant velocity instead of overall heat transfer *** revealed that velocity-search algorithm yielded very close to the important physical and thermal parameters of condenser compared to the existing design data in large scale nuclear power ***-search algorithm has given less number of condenser design physical parameters that meets the velocity acceptance criteria for longitudinal condenser compared to the transverse ***,velocity-search algorithm is found to be more reliable,robust,and consistent for condenser design compared to the conventional design algorithm used in Log-Mean Temperature Difference method.

关键词： nuclear power plant vacuum condenser velocity-search algorithm tropical region

Thermal Characteristic Identification of an Alcohol Flame by Measuring its Density Gradient in Shack-Hartmann Optical System

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Journal of Thermal Science 2011年第1期20卷 93-96页

作者： md.T.I.khan K.Teramoto Department of Mechanical Engineering Saga University1 HonjoSaga 840-8502Japan

Understanding the flame structure for different combustion in industries has drawn the increasing attention around the ***,for increasing the recent interest of using the hydrogen fuelled vehicles in recent world,structural analysis of flame in combustion chamber has attracted the attention of ***,the high flame temperature and strong flame emissions increase the experimental difficulties,especially,in all kinds of intrusive measurement systems for determining the flame structures and flame ***,a non-intrusive laser interferometer technique based on Shack-Hartmann optical system has been proposed to measure the thermal characteristic of a flame *** the present study,a low-stretched diffusion flame of methanol burner has been ***-Hartmann optical system is a type of wave front *** is commonly used in adaptive optical *** consists of an array of lenses to focus the image onto a photon sensor (photo-detector) at the focal plane and measures the wave front *** major objective of the present study is to develop a laser interferometer measurement technique for analyzing the flame structure and its temperature propagation by measuring the density gradient of the *** interferometer technique is a potential candidate for the non-invasive *** the present paper,a novel method for the measurement of density gradient in flame by using Shack-Hartmann optical system is proposed.A collimated laser beam that has been passed through the flame is tilted due to the density gradient inside the flame.A CCD camera (CCD photo sensor) has been used to observe the wave front tilts at the focal plane.

关键词： Laser Interferometer Density Gradient Shack-Hartmann Optical System Thermal Characteristics Alcohol Flame.

Hydrogen Gas Filling into an Actual Tank at High Pressure and Optimization of Its Thermal Characteristics

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Journal of Thermal Science 2009年第3期18卷 235-240页

作者： md.Tawhidul Islam khan Masanori Monde Toshiaki Setoguchi Department of Mechanical Engineering Saga University

Gas with high pressure is widely used at present as fuel storage mode for different hydrogen vehicles. Differenttypes of materials are used for constructing these hydrogen pressure vessels. An aluminum lined vessel and typicallycarbon fiber reinforced plastic (CFRP) materials are commercially used in hydrogen vessels. An aluminumlined vessel is easy to construct and posses high thermal conductivity compared to other commercially availablevessels. However, compared to CFRP lined vessel, it has low strength capacity and safety factors. Therefore,nowadays, CFRP lined vessels are becoming more popular in hydrogen vehicles. Moreover, CFRP lined vesselhas an advantage of light weight. CFRP, although, has many desirable properties in reducing the weight and inincreasing the strength, it is also necessary to keep the material temperature below 85 ℃ for maintaining stringentsafety requirements. While filling process occurs, the temperature can be exceeded due to the compression worksof the gas flow. Therefore, it is very important to optimize the hydrogen filling system to avoid the crossing of thecritical limit of the temperature rise. Computer-aided simulation has been conducted to characterize the hydrogenfilling to optimize the technique. Three types of hydrogen vessels with different volumes have been analyzed foroptimizing the charging characteristics of hydrogen to test vessels. Gas temperatures are measured inside representativevessels in the supply reservoirs (H2 storages) and at the inlet to the test tank during filling.

关键词： Hydrogen filling thermal characteristics of hydrogen storage CFRP storage tank

Design and simulation to improve the structural efficiency of green light emission of GaN/InGaN/AIGaN light emitting diode

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Frontiers of Optoelectronics 2017年第4期10卷 370-377页

作者： Sakhawat HUSSAIN Tasnim ZERIN md. Ashik khan Department of Electrical and Electronic Engineering University of Dhaka Dhaka-1000 Bangladesh

This study considered the design of an efficient, high brightness polar InGaN/GaN light emitting diode （LED） structure with A1GaN capping layer for green light emission. The deposition of high In （〉 15%） composition within InGaN quantum well （QW） has limitations when providing intense green light. To design an effective model for a highly efficient InGaN green LEDs, this study considered the compositions of indium and aluminum for InxGal xN QW and AlyGal yN cap layers, along with different layer thicknesses of well, barrier and cap. These structural properties significantly affect different properties. For example, these properties affect electric fields of layers, polarization, overall elastic stress energy and lattice parameter of the structure, emission wavelength, and intensity of the emitted light. Three models with different composition and layer thicknesses are simulated and analyzed to obtain green light with in-plane equilibrium lattice parameter close to GaN （3.189 A ） with the highest oscillator strength values. A structure model is obtained with an oscillator strength value of 1.18 × 10-1 and least in-plane equilibrium lattice constant of 3.218 A. This emitter can emit at a wavelength of 540 nm, which is the expected design for the fabrication of highly efficient, bright green LEDs.

关键词： green light emitting diode (LED) latticeparameter oscillator strength InGaN quantum well (QW),A1GaN capping layer

Options and Opportunities for Energy Management in Malaysian Grid Systems-Putrajaya as a Case Study

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Journal of Electronic Science and Technology 2018年第4期16卷 316-324页

作者： Aravind CV Umashankar Subramaniam md Shahrukh Adnan khan md. Ibrahim Ibne Alam School of Engineering Taylor’s University Subang Jaya 47500 Malaysia Department of Energy and Power Electronics VIT University Vellore 632014 India University of Asia Pacific Dhaka 1205 Bangladesh

This paper presents an opportunity for energy management with an integrated photovoltaic and wind farm for the energy and economic aspects of the commercial area located in Putrajaya. The energy economy accession conforming to the wind speed, temperature, solar irradiation, and energy consumption on a daily basis is taken into consideration. Design analysis is done through the industry standard numerical tool. From the result analysis, the recommended ratio of renewable share minimizing stress to the electric grid is proposed. According to the solutions obtained from the numerical design tool, photovoltaic is recommended to be more energy efficient and economically viable in comparison of the fully crowded wind farm. From the proposed solutions, the photovoltaic is able to provide 51% of the energy consumed and it costs RM 0.365 per kW/h.

关键词： Cost grid Homer Pro photovoltaic park wind turbine farm

Unsteady RANS simulation of wind flow around a building shape obstacle

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Building Simulation 2022年第2期15卷 291-312页

作者： Sheikh Hassan md.Mamun Molla Preetom Nag Nasrin Akhter Amirul khan Department of Mathematics&Physics North South UniversityDhaka 1229Bangladesh Department of Mathematics Dhaka University of Engineering&TechnologyGazipur 1708Bangladesh School of Civil Engineering University of LeedsLeeds LS29JTUK

This work aims to find the origin and connection of the surface,near-wake,and far-wake structures in the flow encompassing a high-rise building for a high Reynolds *** origin and interconnection of the stream-wise tip vortices,with the other components of the wake,is analysed in this study for the current *** Unsteady Reynolds Averaged Navier-Stokes equations(URANS)together with the realizable k-εturbulence model have been used in this investigation to study the turbulent wake flow following a ground-surface-attached square shape building.A moderately big obstacle aspect ratio of 4,a Reynolds number of 12,000,and a thin evolving boundary layer thickness have been used in the flow *** designed flow addresses the reversed-flows at the outlet during computation to improve the accuracy of the realizable k-e *** Reynolds stress components are retrieved using the Boussinesq *** wake’s principal compositions,including span-wise-side eddies and area of high stream-wise vorticity in the uppermost portion of the wake,are illustrated by both three-dimensional(3D)representations and planner projections of the mean flow distributions.A braided vortex formation,composed of asymmetric hairpin vortexes,is witnessed in the far-wake *** association of the near-wake vortex structures with the far-wake and near-wall flow,which is associated with the flow strengths,is also *** this investigation,few areas of large stream-wise vorticity magnitude,like tip vortexes,are correlated to the 3D curving of the fluid motion,and tip vortices did not continuously reach to the free end part of the *** 3D fluid motion interpretation,which combined several measurements of the flow distribution encompassing the cylinder,shows that the time-averaged near-wake structures are formed of two segments of distinct source and section of ***,addressing reversed-flow during computation shows notable improvement in the results.

关键词： turbulent wake vortex shedding flow structures tip vortexes model building URANS turbulent boundary layer

Determining asphalt surface temperature using weather parameters

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第6期6卷 577-588页

作者： Zafrul H.khan md Rashadul Islam Rafiqul A.Tarefder Department of Civil Engineering University of New MexicoAlbuquerqueNM 87131USA Civil Engineering Technology Colorado State University-PuebloPuebloCO 81001USA

Temperature affects the structural response of asphalt concrete(AC) pavement To evaluate the performance,it is important to accurately predict the pavement surface *** study develops three regression models to determine the surface temperature of an asphalt pavement using field measured data such as air temperature,wind speed,wind direction,relative humidity,and solar *** models namely,24-h model,day-time model and night-time model were developed based on one-year continuous *** weather data were measured from October 2012 to October 2013 at an instrumented pavement section on Interstate I-40 near Albuquerque,New *** developed regression models were validated using October 2014 to June 2015 weather data,which were not used in developing the regression *** temperatures predicted using the developed regression models were then compared to those predicted using the pavement mechanistic-empirical(ME) software’s default *** is observed that the regression models are better predictors of pavement surface temperatures than the ME default models.A parametric study was also performed in this study to identify the effects of weather parameters on the pavement surface temperature *** authors of this study expect that this study will be useful in pavement design especially in cold regions.

关键词： Asphalt pavement Air temperature Surface temperature Wind Relative humidity Solar radiation