BES Journal

Journal
2010
Performance Analysis of OFDM for Different Digital Modulation Schemes using Matlab Simulation
Md. Shariful Islam*1, Md. Asek Raihan Mahmud1 , Md. Alamgir Hossain1 , Md. Sadek Ali1
In this Paper, proposed OFDM system design is simulated using Matlab simulink toolbox. The digital modulation schemes such as M-PSK (M-ary Phase Shift Keying) and M-QAM (M-ary Quadrature Amplitude Modulation), which provide way of parallel transmission, are compared to analyze the BER performance of designed OFDM system. Mentioned schemes used in OFDM system can be selected on the basis of the requirement of power or spectrum efficiency and BER analysis. In wireless communication, concept of parallel transmission of symbols is applied to achieve high throughput and better transmission quality. OFDM is one of the techniques for parallel transmission.
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Installation and Deployment of WiMAX for Campus Network
Dilshad Mahjabeen1 , Anis Ahmed2 , and Shahida Rafique2
The necessary design steps for the implementation and deployment of WiMAX in a particular region have been discussed. At first, deployment technique and issues of WiMAX campus network are described. A model is proposed for fixed WiMAX connectivity using the WiMAX gateway as a backbone and modem for access purposes. The model is done under some real world application for the campus of University of Dhaka, Republic of Bangladesh. The benefit of WiMAX campus networking is compared with other options. As WiMAX is low cost for both implementation and ongoing charges, it will be the best candidate for Bangladesh to provide high speed Internet through wireless network.
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Study on grid-tied solar energy system at Dhaka
Khademul Islam, Himangshu Ranjan Ghosh*and Neem Chandra Bhowmik
A grid connected solar energy system enables users to sell any excess power to the electric utility through a plan known as net metering. Study on a virtual power plant with 5kWP solar panels shows that if the household consumption is zero, the plant can deliver 6198kWh electricity to the 220V distribution line of national grid each year. Evaluating the economic value of the plant for 20 years the energy production cost is around 23BDT/kWh while the value is 17 to 37BDT/kWh at the diesel based power plants in national grid. Moreover as the intermittent energy production from the proposed solar power system is less than 5% of the total electricity supply at the distribution lines, the grid electricity quality will not be hampered.
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Design and Development of PC Based Integrated Data Acquisition System for pH and Temperature measurement
Tania Zaman1 , Abdullah Al Mamun2 , Anisa Begum2 and Shamima Karim Choudhury1
A PC based integrated data acquisition system for pH and Temperature is designed and developed to improve the performance and flexibility of the data acquisition system compared with traditional approaches. For this acquisition system, an analog signal conditioning circuit board is designed to extract the signals from the sensors of pH and temperature. This board is interfaced to PC through a data acquisition board that is installed in the PCI slot. Graphical programming software LabVIEW is used to design programs that provide the instrumental control and acquisition for the experimental data. This developed virtual instrument has the facilities of calibration for accurate measurements and also has the data logging system to store, analyze data for future use. pH of various materials has been measured with temperature and compared them to the reference values which show the accuracy of the system. A comparative study of pH vs. temperature has been done for 3 familiar materials that show the pH value increases with temperature. The system is cost-effective and user friendly and can be used for medical, industrial, chemical or home applications.
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First-Order Optimization Method for Single and Multiple-Layer Feedforward Artificial Neural Networks
Muhammad Hanif1 and Jamal Nazrul Islam2
In this study, we apply the first-order optimization method in single and multiple-layer feedforward artificial neural networking problem and obtained some useful results. Trial and error basis has been applied in determining the internal parameters of the network considered as having a significant influence over its performance: the number of hidden layers, activation function, number of neurons in the hidden layers, training epochs, learning rate, and momentum term. Several practical examples were chosen to exemplify the use of the algorithm for finding the optimal parameters.
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The Way ESPRIT Algorithm Based on DOA Estimation Exploits on a Smart Antenna
Ummee Tania Ahmed1 , Md. Sekendar Ali1 , Abdul Matin Patwari1 and Md.Abdul Matin2
In this simulation, ESPRIT (Estimation of signal parameters via rotational invariance technique) algorithm with uncorrelated narrowband signal is applied on a smart antenna. The whole simulation is divided into three stages. These are Angle of Arrival Estimation, Adaptive Beam forming and Signal Regeneration. It has been studied for different signal to noise ratio (SNR) and DOA (direction of arrival) angles. A linear antenna array of four elements is used, which operate at 2GHz with 0.075m inter-element spacing. The signal impinging directions termed as DOA (direction of arrival) angles are set to 30o , 60o and 90o , in the vertical and horizontal planes for SNR values of 10dB, 50dB and 100dB.
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Reactive CDS Based Enhancement of Dynamic Source Routing Protocol to Alleviate ‘Broadcast Storm’ Problem
Rebeka Tanij Tania1 , Ajmery Sultana2 , Abdullah Al Mamun2
A Mobile Ad Hoc Network (MANET) is an autonomous system of functionally equivalent mobile nodes, which must be able to communicate while moving, without any kind of wired infrastructure. To this end, mobile nodes must cooperate to provide the routing service. Routing in mobile environments is challenging due to the constraints existing on the resources and the required ability of the protocol to effectively track topological changes. Reactive routing protocols perform well in such an environment due to their ability to cope quickly against topological changes. The paper focuses on analyzing an On Demand Ad hoc Routing Protocols “Dynamic Source Routing (DSR), its broadcast storm problem in the route discovery phase which has the very negative impact on the performance of the protocol. The complete DSR implementation has been studied and also implements a simple, efficient idea on DSR to make a reactive connected dominating set (CDS) in the purpose of reducing the aforementioned problem and enhance the performance thereby. The performance analysis is done by using Network Simulator (NS-2).
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One Step Synthesis and Optical Evaluation of Copper Oxide (CuO) Nanoparticles
*M. Abdul Momin1 , Roksana Pervin1 , M. Jalal Uddin1 G.M. Arifuzzaman Khan2 and Momtazul Islam1
One-dimensional nanostructural materials are currently the focus of considerable interest. Many methods have been used for the preparation of nanoparticles. However, to our knowledge, complex process control, high reaction temperatures or long synthesis time may be required for these approaches. Here we report a novel and simple one-step for synthesis of highly stable and freestanding cupric oxide (CuO) nanoparticles of approximately 10 and 12 nm in size which have been successfully synthesized via electrochemical method. Ultraviolet-visible spectroscopy (UV-VIS), X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR) were introduced to characterize the samples. The results indicate that growth conditions are responsible for different sizes.
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Study of the Structural, Electrical and Magnetic Properties of Co Ferrite
K.M.A. Hussain1 , Ali Asgar2 , AKMA Hakim1 and M. N. I. Khan1
Bulk CoxFe3-xO4 (x = 1, 0.75, 0.50, 0.25) samples were prepared by conventional solid-state reaction method and sintered at 1300K. Effects of Co substitution on lattice parameter, density, porosity, dielectric and magnetic properties of ferrite were investigated thoroughly. Single phase spinel structure of all the sintered samples are confirmed by X-ray diffraction. Lattice parameter found to be increased linearly with increasing Co substitution. Initial permeability and frequency dependence of the complex permeability measurements were carried out by LCR bridge in the frequency range 1 KHz to 13 MHz at room temperature. Permeability was observed to be decreased with the increase of content whereas magnetostriction was increased. Minimum magnetostriction gives maximum permeability due to minimum constrain on the domain wall movement. Thus a consistent relationship was found between permeability and magnetostriction.
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Analysis of Whispering Gallery Modes of an Optical Pillbox Resonator using Finite Element BPM (FE-BPM)
Shirin Akter1 , Nahid Akter2 and Anis Ahmed3
To deal with the radiation from an axially symmetric graded index optical pillbox resonator embeded in LiNbO3 substrate formed by proton exchanged method, an eigenvalue equation is derived using finite-element beam propagation method (FE-BPM) in a cylindrical coordinate system. By solving the eigenvalue equation, the resonant whispering gallery modes and the angular phase constant of resonator are evaluated. In order to fine an optimized characteristics of the resonator, the core radius is taken a=200 m and a resonant wavelength 0 = 0.900115 m . At this wavelength co n and cl n of the proton exchange waveguide in LiNbO3 are found to be 2.293 and 2.165, respectively. Using these values a step-index resonator is analyzed and the obtained results are found in good agreement with the analytical ones. The analysis is carried out for uniform sampling space with sampling point M = 551. The resonant characteristics of an optical resonator at wavelength 1.55 m is also calculated. With increase of wavelength it is found that the number of resonant whispering gallery modes decreases. In order to get a mono-mode resonator, the radius of the resonator should be tailored and take a tradeoff between the size and the desired mode number.
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Coverage Area Estimation for Mobile WiMAX Considering Cell Sectorization
Md. Shamsul Arefin1 , Md. Shakhawat Hossain1 , Tasmia Ahmed1 and Subrata Kumar Aditya2
In this work, coverage area has been estimated for mobile WiMAX considering cell sectoring. Erceg-Greenstein model and Cost-231 model have been used for path loss calculation for urban, suburban and rural areas. Frequency planning is also carried out to reduce the co- channel and adjacent channel interference. Analysis reveals that SNR is inversely proportional to the coverage are for different modulation schemes. Cell range also increases as the transmitted power increases.
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A Satellite Based Method to Determine Land Surface Temperature from NOAA-AVHRR Digital Data
K. Fida Hasan1 , Md. Maruf Morshed2 and Md. Shahjahan Ali3
Land Surface Temperature (LST) is one of the key environmental forcing parameters. It is an important factor in global change studies, estimating radiation budgets, heat balance studies and as a control for climate models. Many Studies have indicated that the estimation of the land surface temperature using the NOAA satellite images is an alternative compared to other ground based methods. In this paper, a method has been developed to determine land surface temperatures for Bangladesh and its adjoining areas using NOAA-AVHRR/3 satellite images. Using this method, surface temperature maps for the study area have been prepared. Temporal variations of surface temperature have been studied taking data of one complete year. From the study, it is seen that though simple, the developed satellite based method can be successfully used to infer environmental parameters for Bangladesh.
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