Chittagong University of Engineering & Technology

About: Chittagong University of Engineering & Technology is a education organization based out in Chittagong, Bangladesh. It is known for research contribution in the topics: Renewable energy & Dielectric. The organization has 1200 authors who have published 1444 publications receiving 10418 citations. The organization is also known as: Engineering College, Chittagong & Bangladesh Institute of Technology, Chittagong.

A review on the sustainability of solar home system for rural electrification

Abstract: For the past 20 years, the solar home system (SHS) has been the dominant means of facilitating energy access for the poorest members of rural communities in the developing world. On paper, SHSs appear to be a sound solution to the difficulties in providing affordable and stable electricity to those likely to be left behind by other approaches. Indeed, evidence to date suggests that use of SHSs has accelerated the global electrification rate. However, there is mounting evidence that the long-term success rate of these systems and their effect on recipient communities is incredibly varied. Prompted by the results of a survey that uncovered widespread negative experiences amongst SHS users in rural Bangladesh, this study presents the results of a systematic literature review into the existing case studies of global SHS deployments. The search terms and websites used are presented clearly alongside the criteria used to filter results. Having identified a lack of long-term case studies the papers obtained are used to extract insights on the evolving strategy of SHS distribution, the mechanisms of SHS failure and crisis posed therein, and the most exciting areas of research for ensuring that when communities become electrified in future, they stay so. A three-element framework is offered for understanding SHS sustainability; community engagement, affordability, and appropriate maintenance infrastructure.

Intensity gradient based edge detection for pixelated communication systems

Abstract: Pixelated optical communication systems transmit data using a series of encoded pixelated images. The decoding of these pixelated images is important for reliable data communication. This study proposes a novel intensity gradient-based edge detection (IGED) method for the received pixelated images. In the first stage of the proposed edge detection algorithm, the intensity difference of neighbouring pixels is calculated in the horizontal or vertical direction depending on the presence of a horizontal or vertical edge. In the second stage, the false edge pixels whose intensity values are less than the threshold are removed. Next, slopes are calculated between the consecutive edge pixels and the appropriate lines are found considering the slopes that have almost the same value. The new IGED method performs edge detection without requiring any anchor pixel blocks. This study also provides a description of a misalignment correction algorithm suitable for pixelated images. Next, the effectiveness of the proposed IGED method is tested through an experimental demonstration. It is shown that the IGED method can properly detect the edges even for pixelated images affected by rotational misalignment. For a given transmitter resolution, the proposed method provides better data rates than the existing methods.

Performance evaluation of MC-CDMA system for the next generation wireless networks

Abstract: Rising demand for system capacity, higher data rate and multimedia services brought to light the concept of Multi Carrier Code Division Multiple Access (MC-CDMA) technique. It is basically the fusion of Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing (OFDM) schemes. As a result, MC-CDMA carries the advantages of both, CDMA and OFDM. Here, CDMA increases the efficiency of bandwidth utilization and OFDM helps to reduce Inter Symbol Interference (ISI) as well as multipath fading. As MC-CDMA is based on OFDM, in this paper, the performance of OFDM system is studied as a prerequisite to analyzing MC-CDMA system. Then the Bit Error Rate (BER) performance of the MC-CDMA system is observed for different modulation techniques using MATLAB. The observations are carried out over Rayleigh fading channel with Additive White Gaussian Noise (AWGN). Walsh-Hadamard (W-H) code is used for spreading, as it reduces the Multiple Access Interference (MAI). It is seen that BPSK and QPSK show better performance in terms of BER. Finally, it is observed that, due to Multi User Interference (MUI) and Multipath Interference (MPI), the performance of MC-CDMA degrades when the number of users in a channel is increased.

Commercial Land Use in Dhaka: An Analysis of Trends and Patterns

Abstract: Dhaka possesses a glorious history of 400 years since it started journey on the left bank of River Burignanga. There goes a saying that, the pre-Mughal Dhaka consisted of 52 bazaars and 53 lanes. The main settlement in this period was limited in between the River Buriganga and Dholai Khal with its center near Bangla Bazar. During the Mughal (1606-1764) reign Dhaka further flourished in the commercial sector and it covered the area presently known as old Dhaka. The Chawk (square) was the main market place of Mughal Dhaka. Till today, it is one of the major wholesale areas of the city and vibrant in a transformed physical and social context. The spatial expansion of Dhaka and formation of new Dhaka started in British period. It was expanded in size and was developed in commerce, administration and industrial sector. Dhaka experienced several inclusions of commercial centers during the Pakistan period (1947-1971) both in planned and unplanned manner. The commercial land development in Dhaka had undergone rapid changes since the independence of Bangladesh. Ribbon commercial development, initiated in the 1960s, became a popular addition to the city fabric. By the early 1980s, private developers started to enter the land market of Dhaka and commercial land development projects are primarily dominated by them. An analysis of commercial land use pattern of Dhaka reveals a long historical background of the growth of Dhaka in relation to the physical, socio-political and cultural context. Dhaka City Corporation area has been considered as the study area. This study aims at describing and analyzing the commercial land use trend of Dhaka from a spatio-temporal perspective. This paper also intends to analyze the contemporary commercial land use pattern of Dhaka city and its associated consequences. The distribution pattern and nature of commercial land uses of Dhaka over time has been studied from urban planning standpoint. For this purpose, land use maps of different periods, have been collected and GIS database have been developed for the preparation of necessary maps. The transformation of Dhaka from a monocentric to a polycentric city has been discussed here in detail. Urban spatial structure indicators such as density profile, average distance per person to Central Business Districts (CBD) have been used to understand the nature and spatial structure of these commercial cores of Dhaka. Necessary land use related data have been collected from Dhaka City Corporation (DCC) and Detail Area Plan (DAP). Several secondary sources have been utilized to collect old land use maps of Dhaka. The historic and concurrent trends of development of commercial land uses in Dhaka as discussed in this paper unveiled various issues regarding the growth of Dhaka and its sustainability.

P300 Speller Based ALS Detection Using Daubechies Wavelet Transform in Electroencephalograph

Abstract: The Brain is the main controller of the human body consisting of neurons which generate electrical signals to control the body. Different neurological diseases can cause brain abnormalities such as ALS that affect the electrical activity of the brain which can be seen in the EEG signal. Therefore, these abnormalities can be detected by analyzing the EEG signal. As the Alpha and Beta waves are recorded during the active state of the brain, the effect of abnormalities can be seen in the waves. This study proposes a technique to detect the brain abnormalities and detect ALS syndromes based on Alpha and Beta waves. In this study, the Alpha and Beta waves are extracted from the raw EEG signal by discrete wavelet transformation. Here, the raw EEG signal is divided into several orthogonal wavelets using Doubechis 4 wavelet transform; Alpha and Beta wave frequency components are selected and reconstructed. Then these waves can be compared between different types of ALS patients and normal people based on amplitude and event related potential. The result showed great variation in amplitude as well as event related potential for different ALS patients and normal people. The proposed technique could be used in detecting abnormalities and their severity. It could also help in detecting ALS at a primary stage.