The AIUB Journal of Science and Engineering (AJSE)
Vol 15 No 1 August 2016
Numerical Simulations of Terahertz Radiation from a Finite-sized Bow-tie Antenna Integrated with a Semiconductor Mesa and External Microstrip Lines
M. Suhara
Tokyo Metropolitan University, Japan
Y. Kato
Tokyo Metropolitan University, Japan
H. Yamakura
Tokyo Metropolitan University, Japan
K. Asakawa
Tokyo Metropolitan College of Industrial Technology, Japan
Abstract
An integrated thin-film bow-tie antenna structure is designed and analyzed for terahertz oscillator. The structure consists of a semiconductor mesa, an integrated bow-tie antenna with external microstrip lines, and an existence of substrate. Appropriate structural designs are clarified with respect to broadband radiation characteristics due to terahertz oscillations in the proposed integrated device. Our analysis is on the basis of cooperation of plural methods including numerical electromagnetic simulations, modern multi-purpose optimization method, nonlinear numerical calculation.
Design and Evaluation of a Miniaturized SWB Patch Antenna
Md. Shafiq Uddin
American International University-Bangladesh, Bangladesh
Farhadur Arifin
American International University-Bangladesh, Bangladesh
Rinku Basak
American International University-Bangladesh, Bangladesh
Abstract
In this paper, a miniaturized super wide band patch antenna is design and evaluated for super wide band applications. The proposed antenna is made from iterations of a hexagonal slot inside a circular patch with a transmission line. A partial ground plane and patch toward the substrate are used for designing the antenna to achieve a super wide bandwidth ranging from 3.1 GHz to 63.5 GHz with a bandwidth ratio of 20.5: 1. The bandwidth and gain of the proposed antenna are much better than the recently reported super wideband antennas which make it appropriate for many wireless communications systems such as WLAN, WPAN and UWB. Moreover, the proposed antenna has a compact volume of 45 mm × 31 mm × 1.58 mm on a Roger RT 5870 substrate with a relative dielectric constant of 2.3. Antenna design and the simulation results of radiation pattern, and gain are presented and discussed in detail.
Field Oriented Control of a Current Fed PMBLDC Motor and Its Comparison to Scalar Control Drive
Protik Chandra Biswas
Khulna University of Engineering & Technology, Bangladesh
Bashudeb Chandra Ghosh
Khulna University of Engineering & Technology, Bangladesh
Md. Ashraful Islam
Khulna University of Engineering & Technology, Bangladesh
Abstract
Permanent Magnet Brushless DC (PMBLDC) Motors are high power density motors with a huge scope to be used as an industrial motor in future. But the motor performance degrades due to improper control actions. In this paper field oriented vector control of a PMBLDC motor drive is presented. Scalar control of this PMBLDC motor is also performed at direct axis current component is equal to 1.0 and at direct axis current component equal to quadrature axis current component. The performances of these control systems are compared under different transient conditions at abnormal situations. An adaptive PI controller is proposed in this paper for these drives. The performance of the vector controlled drive is found to be better than the two different cases of scalar controlled system considering load torque handling capacity, response time, speed overshoot, settling time of the system. For field oriented control, motor can sustain rated speed 150 rad/s for sudden load torque change to rated load torque 1.45 Nm. But for both case of scalar control, speed gradually decreases with the loading of rated load torque.
Optimum Speed Control of SPWM Inverter-fed IPMSM for the Application ED Based EV
Sumon Kumar Ghos
American International University-Bangladesh, Bangladesh
Mohammad Abdul Mannan
American International University-Bangladesh, Bangladesh
Abstract
Recently, the mechanical differential (MD) is going to replace to by electronic differential (ED) to design the modern electrical vehicle (EV) because of its simplicity, faster response, accurate control capability, configurable and many other eminent features. The ED has been designed by incorporating the electrical motors where the dynamic and robust control of motor is important to ensure the good performance of an EV with ED. In this paper, the LQR speed control IPMSM for ED is proposed for an EV to realize the feature of having precise control over torque and speed considering the core losses. Based on the mathematical model of IPMSM with considering core losses a discrete-time augmented has been developed to design LQR speed control system for speed control of SPWM fed IPMSM. The performance of the designed controller is evaluated using MATLAB/Simulink contrivance where all the simulation results put enough evidence that smooth, precise and robust performance is achievable with the proposed controller. Over and again, under variable load condition, the performance of the controller is analyzed and appreciable outcome is attained.
Sustainable Mobility System- Innovative Practices Influenced People Behaviour through the Mobility Engagement System
Jing Shao
Politecnico di Milano, Italy
Chowdhury Akram Hossain
American International University-Bangladesh, Bangladesh
Marco Spadafora
Politecnico di Milano, Italy
Abstract
The path towards a sustainable mobility system is one of the most complicated changes required to modern society. It must be mentioned that it is impossible to drive the transportation system toward a sustainable model without all available best approaches work together. From the perspective of customers, hurdles between customer’s compliance and action need to be moved. “Green customers” who are sensitive to energy saving and environment protection are ignorant of how to make better purchasing decisions, and there is little positive feedback to encourage green behavior. By extracting the elements from several current practices around the world, a future scenario for a prospective sustainable mobility model is suggested. It combines together with commercial business approaches and attractive long time trip to normal public transportation by applying credit mobility mechanism to influence people’s behavior and choices of different public traffic mode in various ways. The suggested future scenario is contributing to the research field of promoting sustainable consumption behavior and development on facilitator for promoting sustainable consumption.
Design of a Parallel Resonant Power Converter Considering the Effects of Parasitic Components
Ahmed Mortuza Saleque
American International University-Bangladesh, Bangladesh
Sujay Baliram Umarjikar
University of Oviedo, Gijon, Spain
Abstract
Resonant converters which are designed without considering parasitic components may lead to a large deviation from zero-voltage switching (ZVS). The goal of this paper is to demonstrate the details design procedure of a parallel resonant converter considering the parasitic components to ensure zero-voltage switching (ZVS) which results in low switching losses. Impedance analyzer device is used to find out the equivalent parasitic circuits of the converter and the PWM signals are generated from TMS320F28335 microcontroller. Based on the proposed design technique a prototype is also developed which is intended to deliver an output voltage of 600V while keeping the power in between 1 kW to 5 kW. The overall design is also simulated using PSIM software to verify the proposed design technique and experimental results.
Downlink Performance of Massive MIMO Wireless Communication System with Different Precoders under Correlated Channel Model
Md. Mahfuzur Rahman
American International University-Bangladesh, Bangladesh
Md. Abu Bakar Siddiqui
American International University-Bangladesh, Bangladesh
Abstract
Massive MIMO is one of the pioneer technologies for the next generation (5G) wireless communication system. The next generation wireless communication system will have to support the exponential growth of data traffic and number of mobile devices. In contrast with the fourth generation communication system, the fifth generation communication system is expected to provide a thousand time system capacity and ten times spectral efficiency than the current technology. To achieve this goal, massive MIMO will play a significant role by deploying hundreds or thousands antenna at the base station (BS) and serving tens or hundreds user simultaneously. It is necessary to use an optimal precoding technique to utilize the full potential of massive MIMO system. In this paper, we have investigated the performance of a massive MIMO downlink system using MMSE, ZF, and MRT precoding techniques. We also investigated the effect of channel correlation on the capacity and BER performance of the system.
Design and Implementation of a Textile Pressure Sensor based on Carbon Impregnated Foam
Nuzat Nuary Alam
American International University-Bangladesh, Bangladesh
Rethwan Faiz
American International University-Bangladesh, Bangladesh
Abstract
The main focus of researchers and manufacturers is to develop simple sensors with minimum cost that ensure equivalent features as provided by existing sensors. In addition, if the sensor is capable to work in non-laboratory-ready environment with low power consumption, is another important feature offered by any sensor design. Considering these features, a textile pressure sensor system is presented in this article. This sensor is economically affordable, soft, light weight, has moderate pressure sensitivity, and requires easier electronic integration. It can work in dusty environment and consumes low power. The sensor is made of carbon impregnated foam and conductive threads. Such sensors can be used in integral control system, in wearable sport trainers, in mats for people tracking or into transport systems to collect passenger usage data, in healthcare applications: posture analysis or non-invasive pressure measurement, etc. Outcomes are analysed for temperature dependency, linearity, hysteresis, and operating range of the sensor.
Islanding Detection of Distributed Generation using PNN based Classification Approach
Didarul Alam Shikder
American International University-Bangladesh, Bangladesh
Most. T. A. Begum
Rajshahi University of Engineering and Technology, Bangladesh
M. R. Alam
American International University-Bangladesh, Bangladesh
Abstract
Distributed generation (DG) embedded distribution systems can lead to a number of problems when, an abrupt unintentional disconnection of DG from the power grid side takes place due to large disturbances. In order to avoid these problems, the DG systems are required to be disconnected as soon as islanding occurs. Conventional protection schemes, such as, vector surge (VS) and rate-of-change-of-frequency (ROCOF) relays do not give assurance of islanding detection for all network conditions. This paper will mainly deal with the development of anti-islanding protection tools using pattern recognition approach; more specifically, a probabilistic neural network (PNN) based islanding detection approach. In this method, multiple electrical variables, such as, voltage, frequency, rotor angle, total harmonic distortion of voltage, rate of changes of voltage, frequency, real power, etc., are obtained from the target DG location and fed to the PNN classifier for automatic classification of islanding event. The comparative analysis of the proposed approach with other methods, such as, decision tree and feed-forward multi layer (FFML) neural network based techniques, reveals that the PNN based scheme is very effective in islanding detection. The proposed algorithm has been tested for a test simulation model and an Australian distribution network; test results indicate its reliability and robustness to a large extent for islanding detection of DG interface in the electrical distribution network.
Design of a Novel Ultra Wide Band Logo Textile Antenna for Wearable Body Area Network Applications and Bending Consequences
Kawshik Shikder
American International University-Bangladesh, Bangladesh
Farhadur Arifin
American International University-Bangladesh, Bangladesh
Abstract
A novel Ultra Wide Band (UWB) wearable logo-type textile antenna for body area networks is presented in this paper. The proposed antenna consists of a hexagonal radiating patch and a partial ground plane. The substrate of the proposed antenna is made of Fleece fabric with permittivity 1.17. Ultra wide bandwidth is achieved by optimizing the geometry, introducing a square notch in the partial ground plane and introducing novel slot pattern on the radiating patch of the antenna. This novel slot represents the logo of author’s university name “American International University-Bangladesh (AIUB)’ and also department name “Electrical and Electronic Engineering (EEE)”. The dimension of the proposed antenna substrate is 38×32×2.05 mm3 and the bandwidth is 27.06 GHz (2.82 GHz - 29.88 GHz) for return loss less than -10 dB. The gain variation is less than 4.641 dBi and average total efficiency more than 86%. The proposed antenna performances are also analyzed at different bending angles. The proposed antenna design details and simulated results are presented by Commercial electromagnetic simulation package CST Microwave Studio.
Schematic Learning Environment for ‘Children with Autism’ in Bangladesh
Irfat Alam
American International University-Bangladesh, Bangladesh
Md. Mizanur Rahman
American International University-Bangladesh, Bangladesh
Ashik Vaskor Mannan
American International University-Bangladesh, Bangladesh
Abstract
Classrooms serve as the major setting for the emotional, cognitive, social, and psychological development 0f children. For children with autism spectrum disorder (ASD), classrooms can help them to develop themselves and make them independent in future. Autism is a kind of attitude where we can find some disabilities in their behavior. If we cannot provide properly designed classrooms for the students with developmental disabilities, they would not be able to learn important skills to live in a society. From various researches, it has been found that, children with ASD might have developmental disabilities, but their intelligence quotient (IQ) level is equal to normal persons. As a matter of fact, their IQ level is in some cases higher than average people. That’s why research is needed to design an inclusive learning environment to remove barriers for the children with ASD. The aim of this paper is to show the result of a schematic learning environment for the children with ASD with an in-depth study of autism and focusing on the issues related to the architecture that might become barriers for children with ASD. Further, some guidelines have been generated to design classrooms for the children with ASD using a qualitative analysis.
Interplay between Soft Edges and Life around Residential Ponds of Old Dhaka: A Crucial Prerequisite for a Lively City
Sarah Bashneen Suchana
Stamford University Bangladesh, Bangladesh
Syeda Tuhin Ara Karim
American International University-Bangladesh, Bangladesh
Abstract
In the last 30 years, Dhaka has experienced a drastic reduction in its physical environment and declination of quality of life due to its rapid urbanization. Thus, conserving the existing green-blue spaces and redefining the soft edges inside residential areas that ensure the enhancement of livability index of inhabitants are also crucial. Therefore, the study emphasizes on behavioral observation around soft edges of the residential ponds with a comprehensive look at the nature and location of the activities concerning Access-Linkage, Activity Patterns, Sociability and Attractiveness. An integrated pattern of interplay between the soft edges and life along three residential ponds of Old Dhaka; DIT Pond, Bangshal Pond & Gol Talab have been identified, analyzed and compared. In addition, this study has recommended an archetypal layout of sustainable soft edge with diverse environments to attract community people to revive the significance of green-blue spaces and rejuvenate the prerequisites for lively city.
Landscape Logics: Structuring the Dispersed Urbanization in Banjarbaru, Indonesia
Md Tarek Morad
American International University-Bangladesh, Bangladesh
Nazifa Zabeen Siddiqua
National University of Singapore, Singapore
Shuva Chowdhury
American International University-Bangladesh, Bangladesh
Abstract
Banjar Bakula is the strategic region of South Kalimantan, Indonesia composed of Banjarmasin, Banjarbaru, and parts of Banjar regency and Barito Kuala. Among these regions, Banjarmasin is known to be a “River City” because of its proximity to the Barito River and Martapura River. Banjarbaru is the new administrative center of the South Kalimantan Province. Water has a close relation with this region considering ecological, transportation, production, spatial and social aspects. Presence of Trishakti deep-water port and Ahmed Yani Airport is an important catalyst for the economic development of this region in both local and global contexts. Like many other Asian cities, the post-colonial development in Banjar Bakula focuses on road based urbanization. Cities are growing rapidly with road based infrastructural development, where waterways are neglected. Though the contemporary urban development is far away from its water based origins, but it serves the region and the inhabitants. From the fieldwork, it is merely visible that, over time this territory had evolved from its various landscape reasoning. Apparently, this landscape logic is the missing link between the emerging dispersed urbanization and identity crisis of this region. This paper illustrates alternative adaptive strategies for landscape network in Banjarbaru city to preserve and protect the natural conditions. At the same time, this network can guide the future urbanization process of this city.
A Learning Dataset Aimed at Predicting the Feedbacks for Bengali Blogs
Shovra Das
American International University-Bangladesh, Bangladesh
Md. Hasibul Hasan
American International University-Bangladesh, Bangladesh
Md Shamsur Rahim
American International University-Bangladesh, Bangladesh
Mohammod Hafizur Rahman
American International University-Bangladesh, Bangladesh
Abstract
Since the innovation of blogging, social media began to explode its popularity. As huge amount of documents appearing in social media, there is an enormous opportunity for the analysis of such documents to find interesting relevance across this ocean of data. This work focuses on the analysis of documents appearing in blogs particularly in Bengali blogs. The key goal of this work is to prepare a machine learning dataset to analyse the data extracted from social media. Additionally the idea of a prediction model has been invoked which allows to forecast the number of feedbacks that a blog document is expected to receive in near future. For these experiments, blog documents were crawled from the Internet and processed to facilitate research.
J/ Y Momentum Spectrum in the Decay of B –Meson in Parton Models
Humaira Haroon
American International University-Bangladesh, Bangladesh
Abstract
In this work we have studied the momentum spectrum of J/Y particles resulting from decay of B–mesons. Using different quark distribution functions obtained from different dynamical assumptions of parton models, we calculated the J/Y momentum distribution, taking into account the boost required for the ‘b’ quark in flight. The theoretical results are compared with experimental data. As the similarity of the fits implies independence of dynamical mechanism, we have also tried to obtain similar results using only phase space and relativistic kinematics. Our work suggests that indeed non–dynamical features play the dominant role in this decay distribution and can explain the experimental data.
Adapting the NeQuick 2 Model to GPS Derived TEC Data at a given Location
S.N.M. Azizul Hoque
American International University-Bangladesh, Bangladesh
Tanvir Ahmed
Shahlalal University of Science and Technology, Bangladesh
Abstract
NeQuick 2 is a three dimensional and time dependent quick run electron density model, specifically designed for trans-ionospheric propagation applications that allows the calculation of the electron density at any given location in the ionosphere and also the Total Electron Content (TEC) along any ground station–to–satellite ray-path. The NeQuick 2 has been used to develop a near-real-time ionosphere electron density retrieval technique based on model adaptation to GPS-derived TEC data. In this paper, this technique is applied to new available data. Statistical comparisons between experimental and reconstructed slant TEC and foF2 valuesshows the remarkable improvement of foF2 reconstruction capabilities.
Discriminating the Students of Universities by their Smoking Habit
K.C. Bhuyan
American International University-Bangladesh, Bangladesh
Jannatul Fardus
American International University-Bangladesh, Bangladesh
Mahfuza Khatun
American International University-Bangladesh, Bangladesh
Abstract
The analysis is done using the data collected from 1012 students of three universities. The students are classified by smoking habit and it is found that 32.9 percent students are smokers, though 88.3 percent students are very much aware of health hazard of smoking. The rate of smoker students is increasing with the change of their age. The female students, in proportion, are more prone to smoking compared to their male peers. The important variable for discrimination among smoker and non-smoker students is sex followed by age and father’s education.
