Showing papers by "International Islamic University, Chittagong published in 2010"

Design and implementation of microcontroller based fuzzy logic control for maximum power point tracking of a photovoltaic system

Abstract: This paper proposes a microcontroller based control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and insolation conditions For the reduction of tracking time, fuzzy logic control algorithm is implemented with the embedded microcontroller for improved performance as compared to conventional techniques in power efficiency and swift maximum power point tracking The system includes a photovoltaic array, a PWM controlled DC-DC converter and sensor circuits The designed controller regulates the converter output voltage by varying duty cycle of the PWM signal using maximum power point (MPP) algorithm and it maximizes the output power extracted from photovoltaic array This paper discusses the low cost implementation of MPP algorithm in a 8-bit microcontroller using the tools and techniques to generate optimized real time code in C for ATMega8 microcontroller which will demonstrate how maximum power point tracker might provide elegant and efficient solution for increasing the efficiency of a solar system based on experimental results rather than on mathematical models

A Network Selection Mechanism for Fourth Generation Communication Networks

Abstract: It has been widely agreed that there will be a co- existence of different radio access technologies in fourth generation communication networks. So there will be a problem of choosing the best access network at a particular time. The selection of the best access network will depend on a number of factors. This work aims to take into account their influence in the selection of the network using a Game theoretical modeling to solve the network selection problem. The paper introduces the concepts of Strategy Space, Quality Points in the Game theoretical context and gives a mathematical mechanism for network selection. Finally it is shown that only the best network serves the service request of the user.

Dynamic DFIG wind farm model with an aggregation technique

Abstract: Wind farms begin to influence the power systems with the increasing amount of wind power penetration The study of such influence justifies the need of a dynamic wind farm model comprising of a large number of generators, but detail models require high simulation computation time An aggregation technique is required to reduce the model order while maintaining its accuracy In this paper, a complete and an aggregated wind farm model with Doubly Fed Induction Generator (DFIG) are presented Simulations have been carried out for both models and compared to demonstrate effectiveness of the aggregated model in terms of accuracy in approximation of the dynamic collective responses at the Point of Common Connection (PCC) and reduction in simulation computation time

Analysis of EEG and EMG signals for detection of Sleep Disordered Breathing events

Abstract: Sleep Disordered Breathing describes a group of disorders characterized by abnormalities of respiratory pattern or the quantity of ventilation during sleep Sleep Disordered Breathing causes disruptions in sleep, yielding waking somnolence, diminished neurocognitive performance, adverse cardiovascular outcomes, insulin resistance and other metabolic dysfunctions Electroencephalography and Electromyography signal analysis enables neurologists and sleep specialists to diagnose and monitor Sleep Disordered Breathing events This paper look into the prospect of identifying sleep disordered breathing events through the analysis of Electroencephalograph and Electromyography signals EEG and EMG signals corresponding to 25 subjects with previously diagnosed with Sleep Disorder Breathing studied and analyzed The detection of Sleep Disordered Breathing events were based on the study of power spectral analysis of EEG and EMG signals The variations in the normalized power of various spectral bands of EEG signals are studied along with the variations in power of the corresponding EMG signals This paper also discusses the probable causes of the aforementioned variations in the EEG and EMG signals

Dynamic TDMA slot reservation protocol for cognitive radio ad hoc networks

Abstract: In this paper, we propose a dynamic TDMA slot reservation (DTSR) protocol for cognitive radio ad hoc networks Quality of Service (QoS) guarantee plays a critically important role in such networks We consider the problem of providing QoS guarantee to users as well as to maintain the most efficient use of scarce bandwidth resources A dynamic frame length expansion and shrinking scheme that controls the excessive increase of unassigned slots has been proposed This method efficiently utilizes the channel bandwidth by assigning unused slots to new neighboring nodes and increasing the frame length when the number of slots in the frame is insufficient to support the neighboring nodes It also shrinks the frame length in an effective way Our proposed scheme, which provides both QoS guarantee and efficient resource utilization, be employed to optimize the channel spatial reuse and maximize the system throughput Extensive simulation results show that the proposed mechanism achieves significant performance improvement in multichannel cognitive radio ad hoc networks

Feature extraction of human sleep EEG signals using wavelet transform and Fourier transform

Abstract: Electroencephalogram (EEG) is a complex signal resulting from postsynaptic potentials of cortical pyramidal cells and an important brain state indicator with specific state dependent features. Modern brain research is intimately linked to the feasibility to record the EEG and to its quantitative analysis. EEG spectral analysis is an important method to investigate the hidden properties and hence the brain activities. Spectral analysis of sleep EEG signal provides acute insight into the features of different stages of sleep which can be utilized to differentiate between normal and pathological conditions. This paper describes the process of extracting features of human sleep EEG signals through the use of multi resolution Discrete Wavelet Transform and Fast Fourier Transform. Discrete Wavelet Transform offers representations of the signals in the time-frequency plane giving information regarding the time localization of the spectral components at different stages of sleep in human beings and Fast Fourier Transform provides the spectral information. This paper also discusses the clinical correlation associated with sleep EEG signals in brief.

Housing finance of australian islamic financial service providers (ifsps): an empirical analysis from sharô cahperspectives

Abstract: The purpose of this study is to examine the extent of divergence in the practice of Islamic housing finance from the Shari'ah in the Australian context. It presents a discursive analysis of the extent to which the Australian Islamic Financial Service Providers (IFSPs) differ from the traditional Shari'ah in their current practices of Islamic finance by their use of different mortgage products. The study seeks to argue that the Shari'ah compliance of the IFSPs in housing finance should be strictly maintained, and a separate regulatory and legislative framework be established for Islamic housing finance to facilitate its growth since the underlying principles of Islamic finance differ from those of conventional finance. The approach for the study is restricted to critically examining the extent of divergence of Australian IFSPs from the strict Shari'ah compliance in their current use of different financial products and instruments for housing finance. Therefore, it does not attempt to examine any other Islamic products they use for Islamic finance. Besides, it does not evaluate the economic efficiency and profitability or otherwise, of Islamic finance in Australia. In addition to the direct policy recommendations and suggestions for further research it provides for authorities concerned, the study sheds new light on how the challenges of Shari'ah compliance for IFSPs in Australia are met since theShari'ah contracts they use and advertise appear to be traditional mortgage contracts where the borrower takes the risk and the lender gets a fixed rate of return. JEL Classification: G19, G21, Z12 Key words: Islamic housing finance, Shari'ah, Australia

Power system load switching monitoring using wavelet transform based multiresolution signal decomposition

Abstract: This paper presents a wavelet transform based multiresolution signal decomposition technique for monitoring power system load switching The proposed method depends on the standard deviations of wavelet coefficients calculated at different resolution levels Power system signals are decomposed using discrete wavelet transform based filter bank The simulation results of the study clearly demonstrate that proposed method can efficiently detect and localize power system load switching in time domain The method can also give information on the magnitude of the load switched and its distance from the observation point

Microentrepreneurship Development in Bangladesh: Achievements and Shortcomings

Abstract: Citation Reference: Alam, M.M., Molla, R.I., and Hossain, M.M. 2010. Microentrepreneurship Development in Bangladesh: Achievements and Shortcomings, LAP Lambert Academic Publishing: Saarbrucken, Germany.

Optical properties of semiconducting carbon thin films electrodeposited on Silicon

Abstract: Carbon thin films were deposited on Silicon (Si) substrates by electrolysis of methanol. The effect of camphor (C 10 H 16 O) — a natural source, incorporation in methanol is investigated. Camphor with varying amount (2%, 4%, 6% and 8%) was mixed in methanol solvent to prepare the electrolytes. Silicon substrates were mounted on the negative electrode. Remarkable change in the variation of current density as a function of applied potential was observed with camphor content. The films were characterized by optical microscopy, scanning electron microscopy (SEM), and optical transmittance/reflectance measurement by UV-VIS-NIR techniques. From optical microscopy and SEM micrograph sharp differences between deposited films are observed. FTIR spectra show absorption peaks in between 1250cm−1 to 1750 cm−1 which is the characteristic of diamond like carbon (DLC)/ amorphous carbon (a-C) films. From the transmittance/reflectance measurement of Si substrate samples for different percentage of camphor in methanol (0% and 6%) using UV-VIS-NIR technique it is found that the optical properties like optical transmittance, reflectance and absorption are different for different samples (due to change in camphor incorporation with methanol). And it is found that the optical band gap for Si substrate using only methanol solution is 1.1 eV then by adding 6% camphor into the solution it increases to 1.2 eV.

Socioeconomic Profile of Farmer in Malaysia: Study on Integrated Agricultural Development Area in North-West Selangor

Abstract: Agricultural contribution to GDP in Malaysia has been declining since 1970. The usages of agricultural land are also gradually decreasing. Even within the total agricultural area, most of the land has been used for industrial crops, and the ratio between industrial crops and food crops is increasing. Paddy is the main food crop in Malaysia, but as a low rate of productivity, farmers are engaged on part time basis. Therefore, it seems necessary to know the socioeconomic characteristics of the paddy farmers, their livelihood, and agricultural sustainability for policy implementation and its evaluation. This study analyzes the current profile of the paddy farmers in the Integrated Agricultural Development Area (IADA), North-West Selangor, Malaysia based on primary data. The data was collected through a questionnaire survey. Findings of the study suggest policy recommendations and action plans for the improvement of the farmers’ livelihood. The findings of the study are important for the policy makers and relevant agencies.