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1-bend orthogonal drawings of triconnected planar 4-graphs
(Department of Computer Science and Engineering, BUET, 2007-10) Abu Hasnat Mohammad Asfak Habib; Rahman, Dr. Md. Saidur
An orthogonal drawing of a planar graph is a drawing of the graph in which each vertex is mapped to a point, each edge is drawn as a sequence of alternate horizontal and vertical line segments, and any two edges do not cross except at their common end. In an orthogonal drawing, a bend is a point at which the drawing of an edge changes its direction. Every planar 4-graph i.e. a graph with vertices of the maximum degree at most four, has an orthogonal drawing, but may need bends. If the bend per edge of an orthogonal drawing is at most k,then we call the drawing a k-bend orthogonal drawing. It is already known that every planar 4-graph except an octahedron has a 2-bend orthogonal drawing. Moreover, it is an NP-complete problem to decide whether a given planar 4-graph has a Q-bendorthogonal drawing or not. In this thesis we consider I-bend orthogonal drawings for planar 4-graphs. But unfortunately not every planar 4-graph has a I-bend orthogonal drawing. That is why it is also interesting to find which class of planar 4-graphs has 1- bend orthogonal drawings. In this thesis we give a sufficient condition for a triconnected planar 4-graph to have a I-bend orthogonal drawing. Furthermore, we give a lineartime algorithm for finding I-bend orthogonal drawings of those graphs which satisfy the sufficient condition.
1D nonlinear site response analysis of DMDP area, Bangladesh
(Department of Civil Engineering, 2023-06-17) Abul, Khair; Ansary, Dr. Mehedi Ahmed
The purpose of this research is to perform 1D site response analysis using Standard Penetration Test (SPT) and shear-wave velocity of the Dhaka Metropolitan Development Plan area (DMDP), Bangladesh. Additionally, the result obtained from the 1D analysis has been validated through microtremor analysis result. For this purpose, fifty locations were selected in the study area and the selected locations maintain approximately a uniform distribution within the whole DMDP area. Most of the locations are located on reclaimed areas with sand filling up to a depth of 10 to 15m or more. The depth of boreholes varies between 30 to 85.5m depending on the SPT-N value of 65 or more in the last consecutive 3 layers. After completing SPT a 100mm PVC pipe was installed in the same hole to obtain shear-wave velocity using the seismic downhole technique. The shear-wave velocity beyond the borehole depth has been taken from CDMP 2009 data applying the closest pair of points between the test borehole to the CDMP test point. For estimating site responses for those selected fifty locations, a computer program DEEPSOIL was used. Soil layer depth, unit weight, shear wave velocity (Vs) and soil shear strength as inputs, soil site responses were estimated by equivalent linear and non-linear analysis. Total ten input motions were used in these analyses, which were scaled to 0.13g value for bedrock in the Dhaka region. Besides, a microtremor recording has been carried out at every location of those fifty borehole locations. Microtremor data has been collected according to the guideline of SESAME. Finally, a Horizontal to Vertical spectral Ratio (HVR) curve has been obtained of the site to compare with the 1D response analysis. From the detailed site-specific analysis, it was observed that the amplification factor of the study area ranges 3.1 to 5.5 for nonlinear analysis and 3.8 to 8.5 for equivalent linear analysis and the amplification factor obtained from microtremor analysis ranges 1.3 to 6.6. In areas of thick and soft Holocene deposit the amplification is more than the areas where shallow valleys of Pleistocene deposits with artificially filled sand or any clay in top layer. The peak spectral acceleration (PSA) for 50 sites varies between 0.41g to 0.80g in the case of nonlinear analysis whereas the range of PSA is 0.50g to 1.12g for equivalent linear analysis. It also observed that, the peak ground acceleration (PGA) of the study points ranges 0.17g to 0.26g for non-linear analysis and 0.22g to 0.43g for equivalent linear analysis.
2-D modeling of subthreshold characteristics of symmetric and asymmetric double gate junctionless field effect transistors
(Department of Electrical and Electronic Engineering (EEE), 2015-08) Imtiaz Ahmed; Khosru, Dr. Quazi Deen Mohd.
The miniaturization of traditional planar Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) becomes quite challenging for very short channel devices as the formation of ultra-sharp source and drain junctions with a high process complexity is needed. Junctionless Field Effect Transistors (JLFETs) are considered promising for the sub-20 nm era due to their constant doping profile from source to drain. They provide a great scalability without the need for rigorously controlled doping and activation techniques as well as reduced short channel effects (SCEs) compared to the conventional MOSFETs. Though a number of analytical and simulation studies based on one-dimensional (1-D) model for Double Gate (DG) JLFETs have been carried out over the past few years but rigorous and accurate two-dimensional (2-D) analytical study on this device is yet to be reported. This work proposes a physically based analytical model of 2-D electrostatic potential in the channel applicable for both symmetric and asymmetric DG JLFETs considering similar and dissimilar gate biased configurations operating in the subthreshold region. The model is derived by solving 2-D Poisson’s equation along the channel while assuming a cubic potential distribution across the silicon thickness using appropriate boundary conditions and 1-D capacitance model. Different device parameters like channel doping concentration, thicknesses of silicon channel, top and bottom gate oxide, gate length, applied drain and gate biases, flat-band voltages of gates etc. are included in this model. To justify the accuracy of the model, Poisson’s equation with the same boundary conditions is solved in the COMSOL Multiphysics using Finite Element Method (FEM) and the obtained results are matched with those of the modeled ones. The obtained results from analytical model is also matched with SILVACO ATLAS simulation results to underpin the validity of this model. The proposed potential model is compared with the reported data available in the literature for short channel symmetric DG JLFET. In order to avoid extensive mathematical complexity numerical techniques by MATLAB is further used to calculate threshold voltage, subthreshold drain current and different SCEs viz. threshold voltage roll-off (TVRO), drain induced barrier lowering (DIBL), subthreshold swing (SS) from the proposed analytical model for different structures of DG JLFETs. A detail comparative study of potential distribution in the channel region for different gate and drain voltages obtained from the proposed analytical model is performed for symmetric and asymmetric DG JLFETs. The effect of bottom gate flat-band voltage of asymmetric structures and bottom gate voltage of dissimilar gate biased structures on the threshold voltage are investigated. Finally a performance comparison of subthreshold behavior i.e. TVRO, DIBL, drain current and SS have been made between symmetric and asymmetric DG JLFETs. Both symmetric and asymmetric DG JLFETs show nearly ideal TVRO (~0V), DIBL (~0mV/V) and SS (~60mV/decade) at the gate length around 50nm which make them good competitors of the conventional MOSFETs for short channel devices.
3-D correction of ring and radiant artifacts in flat panel detector based cone beam volume CT imaging
(Department of Electrical and Electronic Engineering (EEE), 2011-03) Emran Mohammad Abu Anas; Kamrul Hasan, Dr. Md.
The use of °at-panel detectors (FPDs) is becoming increasingly popular in cone beam volume and multi-slice CT imaging. But due to the presence of the defective and insu±cient calibrated detector elements in the FPD, the diagnostic quality of the FPD-based CT images in both CT systems is degraded by ring and radiant artifacts. In this thesis, a detail analysis including the classi¯cation, detection and correction of these ring artifacts is presented. Unlike conventional approaches, we emphasize here on the separate detection and correction schemes for each type of rings for their e®ective removal. Two di®erent ring and radiant artifact correction algorithms are presented here: one is applicable for the fan or parallel beam geometry based multi-slice CT and the other for the cone beam geometry based CT. For the correction of the ring artifacts in multi-slice CT, an artifact strength based sinogram-processing method is presented and a mathematical index is used to isolate the defective and mis-calibrated pixels from the good ones. For the correction of artifacts resulting from the defective detector elements, 2D variable window moving average and weighted moving average ¯lters are proposed. On the other hand, the normalization correction scheme is adopted to correct the responses of the mis- calibrated detector elements. Next, a novel approach is presented to eliminate the ring and radiant artifacts of a 3-D cone beam volume CT image using the proposed sinogram based ring artifact removal method. Finally, an e®ective and fast ring artifact correction technique speci¯cally for 3-D cone beam volume CT image is proposed. Some template images are derived from the responses of the detector pixels using their statistical properties and then, an e®ective non-causal derivative based detection algorithm in 2-D space is presented for the detection of defective and mis- calibrated detector elements separately. An image inpainting based 3-D correction scheme is proposed for the estimation of responses of defective pixels and the responses of the mis-calibrated pixels are corrected using the normalization technique. A simpli¯cation of the proposed method is also suggested for its real time implementation. The overall experimental results demonstrate the superiority of the proposed two correction methods (applicable for the multi-slice and cone beam CTs) over the other methods reported in the literature.
3-D model of wrap around CNTEFT with multiple CNT channel and analytical modeling of its capacitances
(Department of Electrical and Electronic Engineering (EEE), 2013-05) Rakibul Karim Akanda, Md.; Khosru, Dr. Quazi Deen Mohd.
Wrap around CNTFET has gate around it except the bottom portion. Wrap around gate carbon nanotube field effect transistor (CNTFET) has the advantage of more accurately controlled channel than top gated CNTFET. 3-D simulation is performed using Finite Element Method (FEM) to model wrap around CNTFET with multi-CNT channel. For predicting the device speed, capacitance modeling is necessary. Along with gate to channel capacitance, there are fringing capacitance as well. Analytical expressions to model various capacitances of the same device are also derived from capacitances for 1-D FET with multiple cylindrical conducting channels incorporating screening effect due to multiple CNT. Various capacitances thus obtained exhibit remarkable improvement over planar top gate device with multiple conducting channels. This is attributed to the charge enhancement and better charge confinement in the channel of the wrap around CNTFET with multi-CNT channel. Capacitances are also extracted from the proposed FEM model. The extracted capacitances are in excellent agreement with the capacitances obtained from the analytical model presented in this study. Temperature distribution of wrap around CNTFET with multi-cnt is presented in this paper. For predicting the device characteristics, temperature modeling is necessary. Temperature distribution is changed due to multi-cnt as voltage of adjacent cnt affects temperature of mid cnt. Again it is also changed by temperature dependent thermal conductivity of single walled carbon nano tube (SWCNT). Current flow is changed both due to multi-cnt wrap around structure and due to the temperature change. So, temperature has a great impact on current modeling and thus on device characteristics. All these issues are considered in this paper using finite element method.
3D numerical study of thermofluid characteristics of a flat plate solar collector using nanofluid
(Department of Mathematics (Math), 2015-08) Rehena Nasrin; Abdul Alim, Dr. Md.
Solar collector generation is growing quickly around the world to lessen some of the negative environmental impacts of the heating sector. The variability of these renewable sources of heat possesses technical and economical challenges when integrated on a large scale. One of the potential solutions to deal with the variations of renewable energy sources, energy storage is being widely regarded. An elaborate theoretical study on thermofluid characteristics of a nanofluid filled flat plate solar collector (FPSC) has been presented in this thesis. The relevant governing equations have been solved by using finite element method. In this thesis numerical analysis has been performed for better understanding of the heat transfer phenomena of the flat plate solar collector using water as well as water/copper nanofluid. Both 2D and 3D models of the flat plate solar collector (FPSC) have been taken into account. Heat transfer and flow characteristics have been presented for various pertinent parameters. Then comparison in various forms has been shown to check whether 3D study is necessary or not. Two correlations for heat transfer rate and thermal efficiency have been developed from obtained 3D results. Higher heat transfer rate of 3%, mean output temperature of 1.6K and collector efficiency of 5% have been obtained in 3D analysis than that of 2D analysis. Not more than 2% solid volume fraction of water/copper nanofluid has found to be advantageous. Suitable mass flow rate has obtained 0.0248Kg/s from this numerical study. More heat transfer rate of 17% and thermal efficiency of 8% has found for using 2% concentrated water/copper nanofluid than base fluid in 3D simulation. Water based nanofluid having double nanoparticles (copper and silver) has also been used as heat transfer medium instead of nanofluid having single nanoparticle (copper or silver) in 3D study to observe whether thermal efficiency of FPSC increases or not. Also a quadratic form of thermal efficiency has been derived using the results obtained from current 3D numerical study and compared with a survey report for a good FPSC available in the literature.
546.718/TOF/2008
(Department of Physics, BUET, 2008-01) Tofayel Hossain Mollah; Khan, Dr. Md. Feroz Alam
For abstracts please see full text
8085-Based universal EPROM programmer
(Department of Electrical and Electronic Engineering, 1985-01) Khandaker Atwar Hossain; Mahbubur Rahman, Dr. Syed
For abstract please see full text
A Study on accessibility of physically Challenged people to some selected urban services and facilities in Dhaka
(Department of Urban and Regional Planning, 2007-03) Touhid, Ahul Baker Md.; Islam, Mrs. Ishrat
Disability development in recenl day, is an irit"cg'ralpart of neo-development paradigm all over the world. Integral part in the sense that. a counlry Can not uplift its soeio-economic conditions unless and until people from all strata of lhc society exercise the choice of better feeding, bCllCreconomic opportunities and better social po,ilions. According to the most recent stutistics nllmber of disabled people in Aanglade~b i~ 5.82%. World Health Organization substantiated tbe figure 10% of the 100aipopulalion in developing eOllntries. Wbatever the rate is, they are many things, value judgment of physically challenged people is enonnous. They can do many things as the fit people can do. So, it must be a r«kless endcavor for overall development if protecling thcir righls, dignities and their welfare as well are not protected; can not be ensured with proper legal and administrative mea,ureS. This sludy can pave the way for doing so. It is an at!empt to know the socio-economic & sociocultural conditions of pbysically challenged people and their accessibility scenario to different lIrban scrvices and facilities in Dhaka. "The study area i~ Dhaka, because urban hazards are maximum here that can lead to establish acccssiblc urban service-facilities in cilie, of Bangladesh. Bangladesh hIlSadopt~ National Di>ability Wdfare Act in 1995. There are specifications for di>ability access mentioned in National Building Code -1993 and Dhaka City Building Construction Rule~ -2006. But lack of propet monitoring, implementation and lack of adequate impetus to protect disability rights Dhaka is far below from a 'disability ftiendly' city. The stlldy, however, is willing to prelude tile necessity of conscious and logieal elTon> to make urban services and facilities i.e. education, hcalth, employment and buiit environment accessible to the physically challenged people in Dhaka. The study explored that, physically challenged people are lagging bebind day by day through unconscious but systematic way of dis<;rimination,. They possess POOtIitemcy rate, they are not healthy, they have very limited job opportunities, they are socially and culturally isolated even in their famlly, all the built environment are somewbat totally inacce~,ible to them. Tbe study has also investigated and evaluated the development activities taken by the public and private institutions working in Dhaka wbich arc found discouraging and somewhat ineffective In nature & extent. To make positive changes in socio-economie spheres of PWDs and to make accessible education, health, employment and built environment; the study has produced a 'policyactivity' matrix. The 'policy-activity' matrix comprised of long tenn, mid-term and short tenn activities. Responsible authorities to perfonn the job arc also enlisted In the matrix.
A Deep Ensemble Approach of Anger Detection From Audio-Textual Conversation
(Department of Computer Science and Engineering (CSE), 2022-05-15) Nahar, Mahjabin; Bayzid, Dr. Md. Shamsuzzoha
Anger detection from conversations has many real-life applications that include improving interpersonal communications, providing customer services, and enhancing workplace performance. Despite its numerous applications in a variety of domains, anger is one of the least studied basic human emotions. The existing works on anger detection mostly deal with audio-only data, though text transcriptions can be directly obtained from spoken conversations. In this thesis, we propose novel deep learning-based approaches for offline and online anger detection from audio-textual data obtained from real-life conversations. Offline anger detection deals with detecting anger from a pre-collected audio-textual conversation, while online anger detection predicts anger in the subsequent utterances of a conversation from the previous utterances. For offline anger detection, we introduce an ensemble approach that combines handcrafted acoustic features, SincNet-based raw waveform features, and BERT-based textual features in a mid-level fusion scheme within an attention-based CNN architecture. In addition, the model includes a gender classifier to incorporate gender information into offline anger detection. On the other hand, for online anger detection, which predicts the anger of future conversational utterances from current (and past) utterances, we propose a transformer-based technique that combines audio and textual features in a mid-level fusion scheme, utilizing an ensemble-based downstream classifier. We demonstrate the efficacy of our proposed approaches using two data sets: the Bengali call-center data set and the IEMOCAP data set. Experimental results show that our proposed approaches outperform the state-of-the-art baselines by a significant margin. For offline anger recognition, our model achieves an F1 score of 85.5% on the Bengali call-center data set and 91.4% on the IEMOCAP data set. For online anger recognition, our model yields an F1 score of 66.9% on the Bengali call-center data set and 67.7% on the IEMOCAP data set. Additionally, we vary different utterance parameters, such as the numbers of input and output utterances and observe their effect on the performance of anger detection.
A Deep Learning Based Framework for 3D Reconstruction of Femur from QCT Images
(Department of Computer Science and Engineering (CSE), 2023-06-21) Sultana, Jamalia; Naznin, Dr. Mahmuda
Deep Learning (DL) based techniques have been proven to be very effective in medical image segmentation and reconstruction of 3D anatomies of a human body. The success of DL methods primarily depends on extensive and accurately annotated datasets. In this research, we propose a semi-supervised deep learning method that we call SSDL utilizing a CNN-based 3D U-Net model for femur segmentation from sparsely annotated Quantitative Computed Tomography (QCT) slices. We have focused only on annotating QCT slices at the proximal end of the femur, forming ball and socket joint with acetabulum for precise segmentation. Using our proposed framework, we generate a segmenting binary mask to segment the femur accurately. Using our proposed framework, a modified DICOM file integrated with the original metadata can be generated, preserving all the required information. We have employed polynomial spline interpolation for 3D reconstruction along with an Island Removal algorithm to eliminate noises, if there is any. The performance of segmentation and 3D reconstruction have been evaluated both qualitatively and quantitatively. Our approach can achieve a Dice Similarity Coefficient of 91.8% for unseen patients and 99.2% for validated patients. Additionally, we have obtained an average Relative Error of 6.61% and 12.08% for volume and surface area, respectively. The proposed approach demonstrates its effectiveness in accurately segmenting and reconstructing the 3D femur from QCT slices.
A first order reliability analysis method under random, fuzzy and interval uncertainty
(Department of Industrial and Production Engineering (IPE), BUET, 2024-03-23) MAHMUD, FAISAL; Zaman, Dr. AKM Kais Bin
As engineering systems become increasingly complex, it is imperative to comprehend and mitigate the influence of uncertainty in reliability analysis. This is essential to ensure the safety and reliability of systems, underscoring the need for a thorough understanding and proactive management of uncertainty in the analysis process. Uncertainty in reliability analysis can be mainly of two types: aleatory uncertainty, which is the inherent randomness of the system, and epistemic uncertainty, which arises due to a lack of knowledge. Traditionally, reliability analysis has focused mostly on aleatory uncertainty, with little consideration given to approaches that successfully include both aleatory and epistemic uncertainties in reliability analysis. With the rapid development of reliability theory, there has been a growing volume of work on how to integrate both of these uncertainties into a reliability analysis framework. However, there have been very few works that have considered hybrid epistemic uncertainty in reliability analysis, and the computational burden of those methods is very high. To overcome these issues, this thesis presents a simultaneous application of interval variables and fuzzy variables to accurately depict epistemic uncertain parameters in reliability analysis. A dual-stage, first-order reliability analysis framework under random, interval, and fuzzy uncertainty has been proposed in this thesis by integrating probability theory and fuzzy set theory. In this thesis, probability distributions are used to model random variables, capturing the inherent stochastic nature of the system, while interval uncertainty is modeled using the worst-case maximum likelihood approach. In addition, fuzzy set theory is utilized to address ambiguity and vagueness, using fuzzy membership functions (FMF) to represent the related uncertainty. This proposed method is a two-stage reliability assessment procedure where, in the first stage, the most probable point is determined using the improved Hasofer-Lind-Rackwitz-Fiessler(iHLRF) method, while the second stage focuses on determining the optimum responses of the performance function. This computational model calculates the maximum and minimum probability of failure for performance functions in the second stage. The effectiveness and feasibility of this proposed approach are shown through the utilization of one mathematical and two engineering problems.
A machine learning based integrated framework for e-commerce management through customized customer retention strategy
(Institute of Appropriate Technology(IAT), BUET, 2024-01-29) Ishrat Jahan; Sanam, Dr.Tahsina Farah
Ine-commerce,itismorecost-effectivetoretainexistingcustomersthantoattractnewones. Therefore, churn control is crucial in managing attrition. This study aims to ad-dressagapintheliteraturebycombiningchurnprediction,customersegmentation,andrecommendationstoprovideacomprehensiveplatformforcustomizedcustomerretentionstrategy.Theframeworkconsistsofthesethreecomponents.ExperimentalanalysisforcustomerchurnpredictionshowsthatCatBoostperformsthebestinthedatasetwith100%accuracyand100%F1-score.Afterselectingthebestclassifier,recursivefeatureelimination (RFE) is applied to find the rank of features for the next step. This paperfills a research gap and contributes to the existing literature in developing a customerretentionmethod. After implementing churn prediction, the cluster tendency test is performed, and theHopkins score is 0.09322634776929459. This score indicates that the dataset is appropriateforclustering.TheCalinski-HarabaszindexofK-meansishigherthanHierarchical Clustering.Comparing k-means, hierarchical clustering, and DBSCAN, k-meansgives the best performance.The resulting cluster profiles are used for personalizedrecommendations. Collaborative filtering coverage is larger than popularity-based recommendations.The root mean square errors (RMSE), mean absolute errors (MAE),and mean square errors (RMSE) are used for comparing criteria. The SVD model hasRMSE 1.26, MAE 0.99, and MSE 1.69. The test time of SVD is 0.00143, which is thelowest.Precisionis89%andrecallis99.80%whichmeansthat89%oftherecommendations apply to users. Our proposed study shows that with this integrated framework,wehaveachievedsignificantimprovement.Ourstudyhasgiventhebestresultineveryphase of the framework. So, integrating product recommendation with customer churnpredictionsandcustomersegmentationwillenablepersonalizedexperiences,proactivecustomer engagement, maximization of customer lifetime value, data-driven decision-making, and a competitive edge in the market in the context of our country.It willalsoprovideastrongandefficientcustomerretentionstrategytomakee-commercefeelsuccessfulinourcountry.Finally,thisresearchinvestigatesthekeysustainabilityindicatorsforintegratingMLine-commercecustomizedcustomerretentionandconductsasystematicassessmenttoprioritizetheindicatorsbasedontheperspectivesofpertinentexperts in the context of Bangladeshi e-business to assess the long-term sustainabilityoftheproposedsystem.
A statistical pattern recognition based damage identification of a bridge using time series modeling of vehicle induced dynamic responses
(Department of Civil Engineering(CE), BUET, 2024-02-25) Hossain Nadim, Md.; Shohel Rana, Dr.
The deterioration of bridge conditions over time is attributed to various degradation processes, including creep, corrosion, cyclic loading, and others. As bridges age and undergo deterioration, monitoring their structural health has emerged as a significant concern in recent decades. The primary focus in this regard is the detection of damage.This research proposes an output only data driven technique for damage identification which will not require any physical model of the structure nor any known input excitation. This study introduces a damage detection technique that relies on evaluating the dynamic acceleration response of a bridge when subjected to the passage of a vehicle.Finite Element Method (FEM) is used to simulate the structure of the bridge and a dynamic half a car model is employed to depict the vehicle and its suspension system.The Vehicle-Bridge Interaction (VBI) is formulated incorporatingthe dynamic models for bridge structure subsystem and vehicle subsystem, interaction constraints and road roughness modelling. Newmark’s-β method is utilized for solving the coupled VBI problem to extract the vehicle-induced acceleration responses.Through the reduction of structural stiffness of a specific element within the bridge, an artificially induced damage is incorporated. The dynamic acceleration responses are fitted to linear and stationary time series models. An automatic model selection method and model order selection method are demonstrated in this study. The appropriate model class and model orders are selected according to the response from undamaged structure using the proposed technique. The model residuals are used as the damage sensitive features. A damage assessing index is presented utilizing a statistical distance metric named Kullback-LeiblerDivergence (KLD). The proposed damage index is used to identify different simulated damage scenarios. An experimental study is also performed on a laboratory scale bridge specimenwitha vehicle model passing over the bridge. The results of the study demonstrate the method’s effectivenessin identifying damage atvarious position of the bridge spanfor different severity levels.
A Study of bankline shifting of the selected reach of Jamuna river left bank using numerical models
(Department of Water Resources Engineering (WRE), 2023-01-09) HAQUE, AKRAMUL; Matin, Dr. Md. Abdul
The present study deals with the development of a computational procedure to predict the morphological behavior of the Jamunariver such as bed level changesand bankline shifting. A reach of 80 kms long left bank of the Jamuna river from Bahadurabad to Sirajganjwas selected for thisstudy .Numerical models named RIVERFLOW 2D, HEC-RAS 1D and multi-variate regression modeling tools have been used. This study also proposes a machine learning technique for the prediction of bank line shifting of river Jamuna based on the results of numerical models.Accordingly, models have been set for the hydro-morphological computation.RIVERFLOW 2D hydro-morphological model has been used for the assessment of erosion-deposition and bed level changes. This model wascalibrated utilizing the water level data collected from BWDB for the year 2018 and then validated for the year 2019. For calibration and validation, the R2 was found to be about 0.86 and 0.93 respectively. In addition, the HEC-RAS 1D hydrodynamic model has been setup, calibrated and validated using the same data. In broad category, two Scenarios have been carried outin the present computational procedure. These are Scenarioi) use of the output of HEC-RAS 1D and regression tools and Scenarioii) use of results of HEC-RAS 2D and regression tools.In Scenario-i, five variables such as maximum velocity, maximum water level, maximum left over bank discharge, maximum slope and minimum waterlevel were taken from the validated 1D hydro-dynamic model.Performance of the prediction of bankline shifting obtained from the computation have been evaluated using statistical parameters, such as RMSE, R2, MSE, and MAE. These performance evaluation have also been carried outfor various types of regression models such as linear regression, tree type regression, boosted, Gaussian, and SVM type regression models. Performance evaluation showed that that the Boosted regression model outperforms the others. For the boosted regression model, the values of RMSE, R2, MSE, and MAE were 25, 0.80, 700, and 10 respectively. On the other hand, in the Scenario- ii, use of results of HEC-RAS 2D and regression tools, three variables such as the minimum water depth, maximum water depth and maximum velocity have been extracted for the purpose of various regression models run. It is found that theprediction of bankline shifting obtained from calibrated and validated boosted regression model performed satisfactorily in whichfor the calibration, the RMSE, R2, MSE, and MAE values were found 38, 0.60, 1444, and 13 respectively. Computational performance of all the models used in the study has also been assessed in terms of discrepancy ratio. Assessment of bed level changes in terms of net erosion and deposition has been analyzed using RIVER FLOW 2D.Model results showed thatmaximum erosion was 17.7 m/year and maximum depositions have been found 7.3 m/year near Bhuapur hard point area.In order to verify the efficacy of prediction of bank lineerosion, Jamuna river left bank data from Google satellite images for the year 2018-2021were also compared.It is found that boosted regression model performed better when compared with others regression models.Based on the statistical parameters (RMSE, MSE, R2, MAE) and discrepancy ratio,Scenario one (HECRAS 1D and regression model) performed comparatively better (RMSE=56, MSE=3200, R2=0.60, MAE=23). On the other hand, Scenariotwo (HECRAS 2D and regression model) performed relatively better (RMSE=50, MSE=2500, R2=0.65, MAE=20) than that of Scenario one. It is hoped that computational procedure suggested in this study based on river models and multi-variate regression tools can be helpful for the analysis of river bank shifting of alluvial rivers.
A study of drainiage systems for selected cities in Bangladesh
(Department of Civil Engineering, 1998-09) Ubaidur Rahman Quabili, Md.; Habibur Rahman, Dr. Md.
The planning and design of urban drainage system can not be successfully conducted without a variety of supporting data relating to the locality of the actual project as well as to the entire region that will be benefited or affected by the project. The drainage design should provide a balanced combination of natural and man-made drainage elements which offer an adequate flood protection for urban developments and minimize drainage impact on receiving waters. It has been noted that although there has been substantial progress made in development of design tools, the progress in the availability and acquisition of supporting data is lacking. Therefore, this study is concentrated on the acquisition of supporting data such as climatic condition, urbanization pattern, topography of land, surface water availability and socio-economic condition of Bangladesh. After conducting the survey on the existing drainage system in the selected towns, the problems were identified and summarized. Some probable solutions are also proposed to overcome the problems and difficulties. These will help in designing and taking decision in the field, in this regard. A new concept on the shape of drain has been suggested to construct the drains in flat areas which allows to flow sullage more efficiently. This shape provides better self cleansing velocity to the sullage flow. Run-off coefficient for some selected areas in Bangladesh have been determined, this may help in assuming run-off co-efficient for any area. Attempt is being made to identify the cost effective drain, over ditch or pond to minimize construction difficulties.
A study of slum upgradation thought community based organization in Dhaka city
(Department of Urban and Regional Planning, 1998-08) Debnath, Krishna Kanta; Shahidul Islam, Dr. Mir
For abstracts please see full text
A Study of traffic in old Dhaka
(Department of Urban and Regional Planning, 1979-11) Laila Baqee (Banu); Gallagher, Mr. Robert A.
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A study on alternative sources of safe drinking water for the arsenic affected areas in Kachua thana of Chandpur district
(Department of Urban and Regional Planning, 2003-10) Matin Miah, M. A.; Shahidul lslam, Dr. Mir
Arsenic contamination in b'Toundwaterand Its toxic effect on hl.lmanhealth is a new public health problem in Bangladesh. In Bangladesh more than 90% of the people are dependent on water supply from the groundwater ~oun;es. For mon::than 50 years, tubewells have been introduced for safe drinkmg water and domestic purposes, Bllt vcry recently the arsemc conlammation in groundv>aterand its effect on human health are creating a problem among the people. The study was undertaken to lUlderstandthe present situation of arsemc contamination 111dnnking water of Bangladesh. It attempts to know the extent and depth of arsenic occurrence In drinking water of tubewells, DPHE, Grameen Bank, NlPSOM, BRAC, BUET and other NGOs ha\'e tested tubewell water in the rural areas of Bangladesh. For thiS purpose, they have followed both laboratory and field kit methods (specially NTPSOYIkit & MERCK kllj, Although arscnic contamination ",as first detected 111Bangladesh by the Department of Public Health Eng1l1eering (DPHE) in 1993, no remarkable remedial aetivmes "'ere sel forth till 1996. According to the latest survey infonnation or the governmental and non-governmental organizatIOns,about 59 lilas out of 64 are marked as arsenic contaminated areas in Bangladesh About 65 million people live in these lilas whose IOtalarea IS 87,390 sq. km. Most of them are living at risk ofbemg affected by arsenic contaminatJon, Arscnic contamination was also found in other parts of the world where no such risk situation 1, round prevailmg as In Bangladesh. A detailed questionnalTe survey was conducted to eoilect mfonnalion on different aspects of arseme contammatlon m dnnking water of tubewells in the study area, Kachua Thana of Chandpur District Using pnmary and sccondary data from reputed and recognized orgamzatlons involved in various arsenic oriented programs along with the help of maps and other statistical techniques, the study is formulated. From thc study, it 1Srevealed that the on going investigation and measurement techniques of arsenic are not sufficient enough to identity the actual picture of the problem in the country as a whole. To save the people of the arsenic affectcd areas of Bangladesh, GO's ~d NGO's are trying to promote different types of water options Kachua Thana of Chandpur Distnct is considered as a vulnerable area of arsenic contammatlon in its b'TOund"atcrand different organizations take Initiatives to proVIdesare water options m the territory. The ,tudy was under taken to know the extent of the prohlem and remedial initiatives taken by different organizations m Kachua Thana of Chandpur District.
A Study on Fluvial Flood Hazard and Risk Assessment of Arial Khan River Floodplain under Future Climate Change Scenarios
(Department of Water Resources Engineering, 2019-01-14) Roy, Binata; Khan, Dr. Md. Sabbir Mostafa
Bangladesh is highly susceptible to flood due to its location at the confluence of the world’s three major basins– Ganges-Brahmaputra-Meghna (GBM) and hydro-meteorological and topographical characteristics of the basins. Increase in temperature and precipitation due to climate change will significantly increase the monsoon flow of the GBM rivers which may lead to more intense and frequent floods in Bangladesh in upcoming decades. In this study, the fluvial flood hazard and risk of Arial Khan River floodplain have been assessed for the predicted climate change scenarios of RCP 2.6 and RCP 8.5. A calibrated and validated SWAT model of GBM basins has been used to project the future flow magnitudes at Bahadurabad Transit (Brahmaputra River) and Hardinge Bridge (Ganges River) for RCP 2.6 and 8.5 scenarios. Using the flow magnitude of these stations as the upstream boundaries, a 1D HEC-RAS model has been set up for the Brahmaputra-Ganges-Padma River for generating future flow magnitude at Mawa of Padma River. Later, the discharge at the offtake of Arial Khan has been calculated establishing a linear regression equation between the Arial Khan and Padma River. Finally, a 1D-2D coupled model of Arial Khan River floodplain has been set up in HEC-RAS. This coupled model is calibrated and validated for Manning's roughness coefficient ‘n’ = 0.015-0.02 for the year of 2015 and 2017 respectively. After calibration and validation, the model is simulated for different periods of RCP 2.6 and RCP 8.5 scenarios: baseline (1976-2005), 2020s (2006-2035), 2050s (2036-2065) and 2080s (2066-2095). The model result shows that the total flood affected area is nearly 15% at the base condition which is increased to 30% and 47% approximately for the 2080s of RCP 2.6 and RCP 8.5 respectively. The hazard assessment reveals that at the base condition, 48%, 34% and 18% area are in the very low, low and high hazard zone respectively. It is increased to manifolds such as 21%, 27%, 34% and 18% in the very low, low, medium and very hazard zone respectively for the 2080s of RCP 2.6 and it became 22%, 26%, 34% and 18% in the low, medium, high and very high hazard zone respectively for the 2080s of RCP 8.5. Similar to hazard, risk assessment also shows that the very low and low risk zone will decrease and high and very high risk zone will increase significantly by the end of 21st century compared to the base period. Incorporation of vulnerability and exposure gives a complete different horizon to the overall assessment. It is found that some medium hazard zones have a high risk of flood damage due to its high exposure and vulnerability to flood while some high hazard zone falls into the low risk zone because of its low exposure and vulnerability. The overall flood assessment for different projections of RCP 2.6 and RCP 8.5 show that there is an increasing trend of the flood from baseline to 2080s, both for RCP 2.6 and RCP 8.5. From baseline to 2050s, the difference between RCP 2.6 and RCP 8.5 is slight. However, this variation becomes very drastic after the 2050s. The inundation pattern, hazard and risk extent increase manifolds in the 2080s of RCP 8.5 than those of RCP 2.6. So future climate change is going to have a terrible effect on the flood situation of Arial Khan River floodplain. The results found in this study provide useful information on projected changes of flood hazard and risk in the Arial Khan River floodplain over the next decades to a century. Additionally, this study will act as a guideline regarding how to incorporate the globalize climate change scenarios of a large basin to a small local river and its floodplain and find out localized flood hazard and risk maps under climate change scenarios.