American International University-Bangladesh (AIUB)
Kitami Institute of Technology, Japan
Kitami Institute of Technology, Japan
This paper work demonstrated an interactive fuzzy logic based torque and speed control for direct torque controlled induction motor (IM). The direct torque control (DTC) strategy has been designed to decouple the flux and torque control by using the energy model of induction motor. Traditional PI controller, which is used for industrial applications for its simplicity, does not meet the requirement (such as minimize the overshoot, steady-state error, robustness under the variation of load disturbance and parameters) for high performance of IM. In this paper two fuzzy logic controllers, which are designed based on energy model of IM, are developed to control the torque and speed of an IM. The drive is simulated successfully using MATLAB/SIMULINK to verify the performance of designed fuzzy-logic controllers. The performance of the drive has been examined under various working conditions. The proposed fuzzy logic controllers work satisfactorily making the drive more suitable for high performance applications.
Northern University – Bangladesh
American International University-Bangladesh (AIUB)
Bangladesh University of Engineering and Technology (BUET)
In this paper, an Al0.22Ga0.78As/ (Al0.41Ga0.49)0.53In0.47P MQW intra-cavity structure Vertical Cavity Surface Emitting Laser (VCSEL) capable of emitting red light output at a wavelength of 670 nm has been designed using a different combination of compound semiconductor materials. In this design, the active region of the VCSEL has been formed using 3 quantum wells, two barrier layers and two SCH layers. After necessary computations of the band gap energy and material gain, the ternary compound of Al0.22Ga0.78As as the quantum well material and quaternary compound material (Al0.41Ga0.49)0.53In0.47P as the barrier material (both lattice matched to GaAs) have been found to be suitable for operating at 670nm. (Al0.41Ga0.49)0.53In0.47P has been used for the 2 SCH layers. Si doped Al0.53In0.47P has been used as the p-cladding material and C doped Al0.53In0.47P has been used as the n-cladding material. The cavity length of the VCSEL has been taken as two lasing wavelength. The VCSEL has been designed for fabrication on a GaAs substrate. The bottom DBR mirror system is designed using 28 pairs of Al0.42Ga0.58As/AlAs which are lattice matched with GaAs substrate. The top DBR mirror system has been designed using 19 pairs of the same Al0.42Ga0.58As/AlAs material. The VCSEL is thus suitable for fabrication using epitaxial growth because all the layers are lattice matched. The performance characteristics of the designed VCSEL have been computed and the obtained plots have been presented which show low threshold current and good performance.
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
The work done in this paper contains improved-optimized physical-layout, area-consumption, simulation-technique and correct biasing-point of a Nano-power Mirror-Amplifier. MAGIC is used for designing and PSPICE is used for simulation with the help of MAGIC extraction-tool. Process-scaling is 0.5µm with silicon-area 1500µmX1500µm. The design shows power dissipation 4.39 nanowatts that can be used as precision-sensor in low-power communication-field. For cost-effective fabrication and speed, multi-die placement is done by designing two sets of chip, placed on four sub-die in a single MOSIS tiny chip die. The designed chip is implemented for sensor applications in optimal-control on environments for improving the piper-betel growth i.e. soil-moisture, sun-shading control, hail control etc.
American International University-Bangladesh (AIUB)
In this paper we carry out an extensive literature survey and analysis on location based services (LBS) with a purpose of identifying major research gaps on LBS. Since most researches address various issues of LBS from a specific perspective, and there is little or none found that examines the development of LBS by integrating a wider set of perspectives, we propose an analyzing tool called technology roadmapping (TRM) for integrating a broader set of perspectives of LBS. A generic TRM process, developed by [1], is adopted, and the TRM process is analyzed and examined comprehensively considering LBS as offerings in order to give a clear view of how broader perspectives of LBS can be integrated. Finally, a case study is included as an empirical example that employs TRM for the development of LBS in Bangladesh.
American International University-Bangladesh (AIUB)
Blekinge Institute of Technology, Sweden
Marna Tech AB, Sweden
This paper presents the hardware verification process of a Singular Value Decomposition (SVD) based OFDM channel estimator. The design has been implemented on a Virtex-II Pro FPGA board and synthesized for an ASIC in 130 nm technology. The design has been verified using the Agilent HP 16822A system consisting of a Logic Analyzer and Pattern Generator. The design has been tested for three different set of random test vectors and worked correctly up to 110 MHz. The verification result shows that successful hardware implementation is possible for this sort of novel, advanced channel estimation strategies, even though no prior implementation and verification of such estimation strategies have been known. Along with the verification process, the paper gives a brief introduction of a SVD based channel estimator and also discusses the hardware synthesis report.
American International University-Bangladesh (AIUB)
In this article, the conforming progressive experimental results to find the optimum wet etchant recipe for creating reversed mesa ridge waveguide (RGW) upon AlGaAs/GaAs based metamorphic laser heterostructure address. Should dry etching treatment form very good vertical shape to the ridge-waveguide wall at any kind of heterostructure, wet etching treatment is chosen to get better degree of freedom of obtaining reverse mesa (more than 900 angle with respect to top surface of) ridge wall structure. Different wet etchants solutions are used in these investigations by varying acid-type and its concentration, hydrogen per oxide concentration, concentration of water, treatment time and process temperature. Among all, a quite promising and competitive reverse mesa ridge achieves for H2SO4:H2O2:H2O (1:8:1) etchant recipe that is treated upon AlGaAs metamorphic heterostructure at (011) crystal orientation of GaAs substrate at 500C.
American International University-Bangladesh (AIUB)
WLAN is an active research topic with considerable work carried out in the areas of performance analysis, QoS provisioning, admission control, voice/video streaming, network coding, security etc. In this work the performance of the IEEE 802.11b WLANs has been derived quantitatively by adopting novel technical procedures and utilizing the exact parameters as advertised by the IEEE 802.11 LAN/MAN Standards Committee. Two metrics namely the theoretical maximum throughput (TMT) and the maximum number of packets transmitted per second (PPS) have been used for this purpose. Numerical calculations demonstrate that the measured throughput is generally well below the expected throughput depending on the data packet sizes, acknowledgment packets, preambles, headers, and checksums etc. From theoretical calculations it is obtained that for short preamble, 11 Mbps data rate and payload size of 1472 bytes (i.e. for a maximum data transmission unit of 1500 bytes), the TMT is 6.24 Mbps and the PPS is 529.
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
Professional five year Bachelor of Architecture program initiated in Bangladesh with the inception of Architecture Department at BUET in 1962. At present the number of Architecture schools offering B.Arch degree has risen to seventeen and nine has produced graduates so far. Six of these nine architecture schools are picked on random selection for the research. The study focuses to identify the challenges of architecture education here in maintaining and improving its quality, responsiveness and competitiveness in a global standard, while it will also illustrate a picture of hope and prospects that is rising on the horizon. Investigating the problems and identifying the prospects while comparing the different crucial factors simultaneously with reference to widely accepted local and international standards would be the first step in suggesting guidelines and strategies to ensure standard for Architecture education in future. The paper finally draws a critical, comparative overview of the existing system to help seek the process which needs to be undertaken in order to ensure a bright future for architecture education scenario of Bangladesh.
Bangladesh University of Engineering and Technology (BUET)
Bangladesh University of Engineering and Technology (BUET)
The presence of ever increasing number of private cars on the busy roads of Dhaka is a general phenomenon of present days. Provision of sufficient parking areas to fulfill the demand is also becoming challenging. Motijheel area is the commercial hub and everyday huge number of vehicles loiters here and park for various time periods (Bari and Efroymson, 2006). In this study existing on-street parking scenario of Dilkusha road (Bolaka to Sonali Bank via Phoenix Bhaban) have been surveyed and analyzed. It has been found that most of the area has no regulatory sign for parking. Although actual number of vehicles that come to the area is less than the expected number of vehicle, but there is a spillover at peak period and a high possibility of spillover at some other time periods. Parking duration of most of the vehicles is within 30 minutes to 1 hr. Findings of the study represent the importance of taking actions to solve parking related problems.
American International University-Bangladesh (AIUB)
Government Titumir College, Bangladesh
Unsteady natural convection heat and mass transfer boundary layer flow past a flat porous plate is investigated. The effects of chemical reactions with Arrhenius activation energy on the velocity, temperature and concentration are also studied in this paper. The governing partial differential equations are reduced to ordinary differential equations by introducing locally similarity transformation [Maleque (2010)]. Numerical solutions to the reduced non-linear similarity equations are then obtained by adopting Runge-Kutta and shooting method using the Nachtsheim- Swigert iteration technique. The results of the numerical solution then presented graphically in the form of velocity, temperature and concentration profiles. Comparison has been made for steady flow (A=0) and shows excellent agreement with Bestman (1990), hence encouragement for the use of the present computations.
University of Malaya, Malaysia
Type-2 diabetes is a major health concern due to the rise in worldwide problems associated with the increase in epidemic proportions of this disease. This study involved in vitro study of AMP-PK activity which is elevated by two selected natural products: EGCG and Salicylate in presence and absence of AMP and also incubation time plays an important role. To determine the anti-diabetic effect of the AMPK activators, at first AMPK was extracted from rat liver and dialysed followed by immunoprecipitation with antibody SIP-2 fused to protein Sepharose A prior to AMPK assay. The AMPK activity of these natural products which was determined by scintillation counter machine was compared to each other to see which one gave the highest activity percentage value. Since the CPM readings were low to draw conclusion, incubation time was increased from 10 to 25 minutes and AMPK was directly eluted from DEAE cellulose column. However, increased incubation time and purification without dialysis method showed higher AMPK activity.
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
Finding of semantic regions is the main objective of segmentation for image understanding. Automatic image segmentation is one of the major difficulties in the field of image processing. The watershed algorithm has some problems, like over segmentation, sensitive to noise, and high computational complexity. To overcome these problems, we have proposed a Modified Watershed (MWS) algorithm for color image segmentation by adaptively selecting threshold and masking mechanism over each color channel before combining the segmentation from each channel into the final one. For qualitative performance, proposed modified watershed algorithm performance compare with four modified watershed algorithms. For quantitative verification, proposed MWS method with two modified watershed algorithms in terms of executing times. The presented method have compared with FCM, RG and HKM techniques for color image Segmentation in 10 different classes of images with respect to PSNR, MSE, PSNRRGB, CQM and RFSIM. It is worth noticing that our proposed approach is low computational complexity. According to the visual and quantitative verifications, the proposed MWS algorithm is better than others three algorithms on the segmentation of color image.
Bangladesh University (BU)
American International University-Bangladesh (AIUB)
American International University-Bangladesh (AIUB)
This study is an attempt at finding the optimal solutions to dynamic resource-constrained scheduling problems. Rather than requiring a different formulation for each scheduling problem variation, a single algorithm and data-structure provides promising performance on many different instances of the general problem. Traditional scheduling methods use search or scheduling rules (heuristics) specific to the project model or constraint formulation. This study uses direct data structure representation for generating optimized schedules.
American International University-Bangladesh (AIUB)
Possibly the greatest danger threatening Bangladesh currently is the disastrous land of the foundation of life, the disastrous land of our environment. This catastrophe is not limited to Bangladesh, but, as we know, is worldwide problem bred by ignorance and greed. An important point to be kept in mind is that demographic tendencies, the protection of the environment and a lasting economic development are closely connected and policies must aim at creating balanced objectives among these fields. Forestry plays a significant role in Bangladesh, contributing to the livelihood and subsistence needs of the predominantly rural population. It provides a source of energy, supplies forest products such as fuel-wood, fodder, timber, poles, thatching grass, medicinal herbs, construction materials and contributes to the conservation and improvement of the country’s environment. About 2.6 million ha or 18% of Bangladesh’s total land area of 14.8 million ha is categorized as forestland which includes state forestland (2.2 million ha) and private homestead forest (0.27 million ha). Roughly 80 % of the landmass is made up of fertile alluvial lowland called the Bangladesh Plain [1 & 2]. They are quickly disappearing due to the savage urbanization. The protection of these fertile lands constitutes a first priority because their disappearance will lead to a natural catastrophe for the development of agriculture. Furthermore, the pollution due to solid wastes and pesticides requires a serious control over the quality and the quantity of the products used. In addition, the loss of species in Bangladesh is an almost irreversible process that inevitably will result in tremendous ecological havoc.
