Politecnico Di Milano, Italy
American International University-Bangladesh
Politecnico Di Milano, Italy
Politecnico Di Milano, Italy
Politecnico Di Milano, Italy
In this paper we have proposed the robust control scheme for an inverted pendulum. Normally for the case of 2 degree of freedom inverted pendulums, the system is not considered much stable with variations in the parameters. Our goal of this paper is to present the robust control, with which it is possible to get more desired stability in worst case scenarios. For our case we have focused on the mathematical model and also designed the control system with variable pendulum masses and other parameters. We have compared the system with LQR (Linear Quadratic Regulator), for a proper understanding of the differences we have found. In the last part we tried to relate our mathematical model with Kharitonov Theorem to find the stability of our proposed model with variations of different parameters.
American International University-Bangladesh
Kitami Institute of Technology, Japan
Kitami Institute of Technology, Japan
The torque ripple of an induction motor is high due to the variable switching frequency where the torque is controlled by the conventional direct torque control strategy. The decoupling control of torque and flux controller can be designed based of the energy model of induction motor by keeping constant switching frequency. The fuzzy logic control system has shown better performance as compared with the proportional plus integral control system in order to avoid the overshoot and steady-state error problems with robust and faster performance. Generally, two input variables are used to design the conventional fuzzy logic control system where a large number of rules are required and output calculation procedure is time-consuming task. Single-input fuzzy logic control is required less number of rules without degrading the performance. Due to the reduced number of fuzzy rules, design the fuzzy logic controller and tuning parameters are easier. In this paper, a single-input fuzzy logic controller for torque and speed control of energy model based induction motor is proposed. The effectiveness of proposed control system is verified by the simulation work which has done by Matlab/Simulink. Simulation results show that the proposed controller is capable to reduce the steady-state error, overshoot problems and the performance of controller is robust under the variations of load torque and parameters. Moreover, it has found that the proposed controller exhibits equivalent performance with the conventional fuzzy logic controller.
American International University-Bangladesh
American International University-Bangladesh
This paper aims to present the gain characteristics of Erbium Doped Fiber
Amplifier. EDFA gain characteristics have been investigated by analyzing gain
equations and also solving the rate equations of the system. Various simulation
of the gain characteristics are performed by varying different parameters such
as signal wavelength, pump power, input signal power, doping density etc. of
EDFA by using MATLAB v7.10 simulation tool. The analysis provides an insight
into the features of EDFA for improving the gain performance by varying
different parameters. It is seen that by varying doped fiber length up to 10 m,
maximum gain of 41 dB can be achieved at pump power of 120 mW. It is also seen
from the simulation that gain reaches to the saturation level at around 150 mW
of pump power. So, after the increase of the pump power there is very negligible
change of gain characteristics. But the effect of variation of doped fiber
length has significant effect on the gain characteristics of EDFA.
KTH Royal Institute of Technology, Sweden
American International University-Bangladesh
KTH Royal Institute of Technology, Sweden
KTH Royal Institute of Technology, Sweden
The trend for the use of wind power has increased over the past decade. Electricity production is directly related to wind conditions, where wind power is placed. Among the many stakeholders of small-scale wind turbines, KTH in Stockholm gave a proposal for installation of a number of facilities on campus. The purpose of the paper is to investigate the suitable placement locations where the wind speed is high to put a wind turbine using a computer-based simulation program like Star CCM++. The result of the simulation has shown that a potential of several areas are where the wind speed increases with respect to the location of buildings and with the climate changes. The best location for placing a wind turbine for maximum electricity production is found considering all the affecting factors.
American International University-Bangladesh
American International University-Bangladesh
American International University-Bangladesh
In this work, the effects of variation of temperature on the performance characteristics of a GaInP – based 635 nm multiple quantum well (MQW) separate confinement heterostructure (SCH) Red Laser are obtained through computations. The material gain of Ga0.73In0.27P/(Al0.5Ga0..5)0.5In0.5P MQW edge emitting laser (EEL) is theoretically obtained. The peak material gain obtained from the analysis is used to study the performance of the designed laser. A maximum output power of 95.75mW and a maximum modulation bandwidth of 18.6 GHz are obtained for this designed laser at 82 mA injection current where the temperature is 300Kand the differential gain is 8×10-16 cm2. Further by increasing the temperature, a performance analysis of the designed laser exposes that above 350 K, the steady state carrier density cannot hold on to a value above threshold level causing the laser to stop working.
American International University-Bangladesh
American International University-Bangladesh
Speed control of the electrical drive is very important to accelerate
productivity, quality and to minimize energy consumption as well as equipment
maintenance. Interior permanent magnet synchronous motor (IPMSM) is one of the
best candidates for electrical drive systems because of its simplicity, smaller
size and higher gap flux density. This paper deals with the design and
simulation of speed control of IPMSM core loss taking into account. The
decoupling control strategies of torque and flux have been developed by using
the field oriented control (FOC) strategy. In order to control speed of IPMSM
using the PI controller, the terminal voltage and frequency have to be varied
which can be achieved by using the sinusoidal pulse-width modulated (SPWM)
inverter. The efficacy of design control system is verified by the simulation
work which has been done by using Matlab/Simulink software. The simulation
studies on various operating conditions of IPMSM showed that the good response
of desired speed even under the variation of load torque.
American International University-Bangladesh
American International University-Bangladesh
Fiber loss is a major drawback when passing signal in long haul fiber optic communication links and optical networks. To boost the signal in long distance Erbium Doped Fiber Amplifier (EDFA) is most frequently used. The performance of EDFA depends on various parameters like, numerical aperture, Er3+ ion density, active fiber length, pump power, pumping wavelength etc. In this work, the gain, output power and noise figure have been investigated in terms of varying different parameters of EDFA (length of EDFA, numerical aperture, Er3+ ion density and pump power) for co- (forward pumping) and counter- (backward pumping) propagation pump scheme. Here, a gain-flattening characteristic of EDFA has been obtained in Conventional band (C-band) (1525-1565nm) by employing the 980nm pump laser. For simulation purpose, OptiSystem 7.0 software has been used. After analyzing, the maximum gain has been obtained as 20.531729dB for co-propagation pump scheme whereas for counter-propagation pump scheme 21.053208dB has been obtained as the maximum gain.
American International University-Bangladesh
American International University-Bangladesh
Waste is a serious environmental hazard and social problem in Bangladesh.
Currently a massive volume of solid waste is generated every day in the
Municipal areas and unfortunately solid waste management is being deteriorated
day by day. Consequently the country has had serious crisis of electricity, load
shedding is now impractical as living standards and become a great barrier in
socio economic growth. Now, interest in renewable energy resources from organic
solid wastes has increased, as there is a huge amount of energy locked in these
wastes. By meeting the both, power generation from solid waste can play a vital
role in socio-economic development of the country. A study on the potential of
such energy resources is presented in this paper. In this respect, internal
combustion engine is a pivotal area to generate energy from these wastes. We
have made an intensive comparison between bio gas and natural gas
characteristics at combustion engine. This paper also demonstrate why should use
bio gas instead of natural gas for generators.
American International University-Bangladesh
American International University-Bangladesh
In this work, comparative performance analysis and optimization of proposed
635nm Quantum Well Red Laser is performed. At 300K, the peak material gain of an
unstrained device is obtained along with the threshold conditions of the device
which has been used for finding the solution to the coupled rate equations. The
rate equation solutions are used to find a steady state output power of 97.97mW
and a maximum -3dB bandwidth of 15.1GHz at an injection current of 90mA for the
unstrained quantum well device, with a threshold current as low as 15.1mA and a
peak emission wavelength at 635nm. Furthermore, introducing compressive strain
of 0.42% into the quantum wells significantly reduces the threshold current to
7.7mA, increasing the output power to 107.78mW and -3dB bandwidth to 23.7GHz,at
a constant peak emission wavelength of 635nm, stating a superior performance
over the unstrained QW device.
American International University-Bangladesh
Bangladesh University of Engineering and Technology, Bangladesh
Post industrial urban discourses advocate for socially responsive urban
environment inspired from the traditional or indigenous urban development to
achieve a more lively and vibrant urban space. The core idea of this discourse
involves conservation of environmental quality and promotion of social equity
which has often failed to address by the anti-organic urban environment of
industrial cities. This paper is a reappraisal of traditional urban morphology
that has a greatest potential for facilitating social equity. The paper aims to
restate the ‘social goals’ of urban planning and design with particular emphasis
on social equity as manifested spatially in traditional urban form and pattern
of Old Dhaka. The inquiry into what makes the urban space socially equitable-is
investigated through empirical analysis of selected area in traditional Dhaka.
It is observed, the traditional ‘Mohalla’ morphology, the narrow, intricate and
winding street pattern with its nodes, squares and dead-ends, mix of urban
functions with predominant shop house typology, the compact and terraced urban
form with courtyard inside- all together creates a physical environment that
promotes social interaction, economic opportunity, equal access and gender
equality of the urban dwellers in Old Dhaka.
Khulna University of Engineering & Technology, Bangladesh
Khulna University of Engineering & Technology, Bangladesh
Islamic University of Technology, Bangladesh
In this paper, investigations are made to find the effect of channeling on the
rear surface of the Ahmed car body. The Ahmed body is used as a model. The k-ε
turbulence model is used in the computational simulation. In this configuration
the rear part of the body was inclined at an angle of 250 with respect to the
horizontal plane. The Ahmed body is placed in a 3D- rectangular numerical domain
with length, width and height equal to 31.925H, 6.493H and 4.861H respectively,
where the body height H = 0.288m. In this simulation a roughness height of
0.0002m is used, where the incoming flow velocity of the fluid is 40m/s.
Channels of different shapes and size are placed at the rear surface of the car
body and the overall drag is analyzed. It is found that in all cases the drags
have increased.
American International University-Bangladesh
American International University-Bangladesh
Effect of variable electro-conductivity on steady MHD forced convective flow of
an incompressible fluid past a continuously moving vertical infinite porous
plate in the presence of heat absorption has been studied. All fluid properties
are assumed constant except the fluid electro-conductivity. The ratio of
electro-conductivities is assumed as the function of velocities ratio. The flow
is assumed to be at small Reynolds numbers so that the induced magnetic field is
neglected. The governing partial differential equations of the MHD convective
boundary layer flow are reduced to nonlinear ordinary differential equations by
introducing suitable similarity transformations. The nonlinear similarity
equations are then solved analytically by employing the perturbation technique
for large suction. The velocity and the temperature profiles, the skin friction
coefficient and the Nusselt number are calculated with the help of Microsoft
office excel 2010 and displayed in graphical and tabular forms showing the
effects of various parameters on them. The nonlinear similarity equations are
also solved numerically by Nachtshiem-Swigert iteration technique for the
validity of analytical solution.
American International University-Bangladesh
American International University-Bangladesh
The present study is based on data collected from 798 students of American
International University- Bangladesh in the academic session 2012-13. Around 87%
of the investigated students are high in awareness of health hazard of smoking
and 32.3 percent of them are smokers as against 34% smokers in the sample.
Awareness and smoking habit are significantly associated. Students’ age and sex
are also significantly associated with smoking habit. As university students
stay maximum time outside the home, they are exposed to smoking due to the
influences of friends and peers. So, their residential accommodation is not a
factor to prohibit them from smoking. However, mothers’ occupation has a
declining impact on smoking habit of their offspring. Other socio-demographic
factors have no significant influence of students smoking habit. Smoking habit
is in declining trend among students who are very much aware of health hazard of
smoking. This is observed by fitting a logistic regression model of smoking
habit.
6th of October University, Egypt
Suez Canal University, Egypt
Suez Canal University, Egypt
In this paper, we introduce an implementation of novel automated tableau-based
theorem prover with some improvements. The proposed approach is implemented
using PROLOG programming language, exploiting its high inference rate. In
addition, we present some computational time improvements to the implementation.
There are several alternative automated theorem prover (ATP) implementations.
However, the majority of these implementations are resolution-based and it does
not provide a way to exploit multi-threading due to the nature of the resolution
method. In contrast, using tableau to develop theorem prover allow us to use
multi-threading approach, since each branch of the tableau is processed
independently of other branches. In addition, arranging the tableau branches is
an important step to have an efficient theorem prover.
American International University-Bangladesh
American International University-Bangladesh
American International University-Bangladesh
Here, we explored several image processing techniques on Bangla numerals for
OCR. The image processing helps in extracting useful information correctly from
the image. In this paper we have presented a method, which uses double layered
feed forwarded neural network. The training algorithm used was descent with
momentum and adaptive LR. To improve the results of recognition a function has
been devised here. The experiments were done with computer generated, uniform
hand written and non-uniform handwritten Bangla numerals.
American International University-Bangladesh
University of Maryland, Baltimore
Road traffic has a direct impact on economy as well as on our environment.
Simulation and modeling of road traffic network can help planning, designing,
operating, and controlling of traffic network system. So traffic simulator can
play a significant role to develop an efficient traffic system. To simulate
traffic on a real road network the simulator has to work with real data. Real
data can be manually given as input or can be automatically generated from other
sources, for example – images, geographical information system (GIS) data, etc.
This paper presents a tool for automatically generating poly-line road network
from real map data. The generated data can be used for traffic simulation on a
real road network as well as stored in XML format and can be used for any
traffic simulator.
Jagannath University, Bangladesh
Temperature is an important climatic input in the context of climate variability. Due to a rapid climatic variation more work is now being done on climate indices like rainfall, temperature and so on. Long term temperature data of three stations in Bangladesh were analyzed. These three cities taken as case study, as these are the prominent cities in Bangladesh. The location from sea also considered. Three elements of temperature; maximum, average and minimum are investigated. The time series of temperature are analyzed with the aim of detecting trends in the variable. The non-parametric Mann-Kendall test and Sen’s slope estimator are used to detecting monotonic trends and as well as develop model for the variables. Trends are computed for 1953-2012 for Dhaka station, 1950-2002 for Chittagong station and 1964-2012 for Rajshahi station, due to sufficient data availability. The result shows a significant change trend from June to December at Chittagong; whereas at Dhaka the trend showed a significant change all the year round accept May. At Rajshahi station, the trend showed a significant change in January and June to September.
