Browsing by Author "Tariquzzaman, Md."

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BDA: Bangla Text Data Augmentation Framework
(Department of Computer Science and Engineering(CSE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2024-06-23) Tariquzzaman, Md.; Anam, Audwit Nafi; Haque, Naimul
Data augmentation can be a valuable technique, particularly in resource-scarce linguistic domains for improving the performance of natural language processing tasks by creat ing new synthetic data instances. This paper introduces a Bangla text Data Augmen tation Framework (BDA) using pre-trained model-based and rule-based approaches, along with a filtering pipeline to ensure semantic similarity and lexical variance be tween augmented and original text. We provide a comprehensive pipeline for the pro posed framework and perform an in-depth analysis of how well it performs in the Bangla text classification tasks. Our framework improved the F1 score of classification tasks by up to 13.92%, 8.58%, and 10.55% among 15%, 50%, and 100% clipping ranges re spectively, across five different datasets. Training with BDA while using only 50% of the available training set achieved the comparable F1 score as normal training with all available data. We provide an extensive study of the performance of each augmentation approach at the clipping ranges of datasets using BanglaBERT and variants of SVM. Furthermore, we discuss the indicators for optimal performance of the BDA framework and its shortcomings with in-depth analysis
Finite-State Predictive Current Control of a Simplified Three-Level Neutral-Point Clamped Inverter
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2019-11) Tariquzzaman, Md.; Habibullah, Dr. Md.
Multilevel inverter is one of the most important parts in renewable energy based power generating section as well as in motor drive applications. The quality of an inverter system depends on current total harmonic distortion (THD), switching loss, fault tolerant ability, dynamic responses, voltage stress, common mode voltage etc. Multilevel inverter yields low current THD, less voltage stress across the semiconductor switches and low switching frequency and thus less switching loss. However, using more number of semiconductor devices and neutral point voltage variation are the common problems for a neutral point clamped inverter. This is why different topologies of multilevel inverter are available in the literature in order to solve the aforementioned problems. The control scheme of a multilevel inverter also plays an important role to guarantee system’s performance. Recently, model predictive control (MPC) draws much attention to the researchers for its intuitive features and easy handling of nonlinearities of a system. The controller uses system model to predict the future behavior of the system over a prediction horizon. The control objectives are met by minimizing a predefined cost function that represents the expected behavior of the system. The objective of the proposed research work is to control the output load current of a three level simplified NPC (3L-SNPC) inverter topology using MPC. The simplified NPC inverter is considered, because less number of semiconductor devices used in the topology, even though further investigation is required on different factors such as voltage stress, common mode voltage, losses and switching frequency. MPC is used as controller because it can handle the dc link capacitors voltages balancing problem in a very intuitive way. Moreover, the average switching frequency reduction and over current protection can be easily implemented. Simulation results show that the proposed 3L-SNPC yields similar current THD, transient and steady state responses, voltage stress on the switches at the load side and over current protection capability as the conventional diode clamped based NPC inverter system. The two dc-link capacitor voltages are balanced properly with a neutral point voltage variation of close to zero. However, in comparison with the conventional NPC inverter, the proposed system is 15.25% computationally expensive which yields long execution time and thus less sampling frequency. In this study, two simplified MPC strategies are proposed for the 3L-SNPC inverter system in order to reduce the computational burden: single voltage vector prediction based MPC and selective voltage vector prediction based MPC. Both simplified strategies yield similar performance as the conventional MPC. The required execution times for the simplified MPC strategies are tested on hardware dSPACE 1104 platform. It is found that the single voltage vector prediction based MPC and the selective voltage vector prediction based MPC are computationally efficient by 8.28% and 62.9%, respectively, in comparison with the conventional MPC strategy. However, the average switching frequency and the overall loss in the proposed 3L-SNPC inverter are higher by 83.33% and 46.3%, respectively, than the conventional NPC inverter for a specified load current.
Studies on Volumetric and Ultrasonic Properties of L-Lysine, L-Ornithine and Glycine in Aqueous Fructose Solution at Different Temperatures
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-03) Tariquzzaman, Md.; Motin, Prof. Dr. Md. Abdul
In this study, the interaction of amino acids (glycine, L-ornithine and L-lysine) in water and aqueous fructose solution has been determined by using volumetric and sound velocity method. Interactions of glycine, L-ornithine and L-lysine in aqueous fructose solution play an important role to understand biochemical process in living cells. Densities and sound velocities of glycine, L-ornithine and L-lysine in water and in aqueous 0.05 mol.kg-1, 0.20 mol.kg-1, 0.35 mol.kg-1 and 0.50 mol.kg-1 fructose solutions have been studied at 293.15K to 318.15K with an interval of 5K. The density data have been used to calculate apparent molar volume (φv), limiting apparent molar volume (φv 0), limiting apparent molar volume transfer (Δtrφv 0), apparent molar expansibilities (δφv 0/δT)p and Hepler’s constant (δ2φv 0/δT2)p. The acoustic properties such as adiabatic compressibility (βs), apparent molar adiabatic compressibility (k), limiting apparent molar adiabatic compressibility (φk 0), apparent molar adiabatic compressibility of transfer (Δtrφk 0), acoustic impedance (Z), relative association (RA) and hydration number (nH) have been calculated by densities and sound velocities data. The densities increase with the increase of concentration of amino acids (glycine, L-ornithine and L-lysine). Densities of glycine, L-ornithine and L-lysine in aqueous fructose solutions are higher than that of glycine, L-ornithine and L-lysine in aqueous solution. The smaller values of experimental slope (Sv) as compared to limiting apparent molar volume (φv 0) values suggest the dominance of solute-solvent interaction over the solute-solute interaction. The true volume (φv 0) of amino acids are found to be order of L-lysine > L-ornithine > glycine. The limiting apparent molar volume transfer (Δtrφv 0) values of glycine, L-ornithine and L-lysine are positive which suggest the dominance of ion-hydrophilic and hydrophilichydrophilic interactions over the hydrophobic-hydrophobic and ion-hydrophobic interaction. The values of limiting apparent molar expansion (δφv 0/δT)p are positive. Hepler’s constant (δ2φv 0/δT2)p values are small negative for all studied amino acids in binary and ternary system suggest the studied systems act as structure maker. The values of partial molar volumes ( 2) increase with increasing of concentration of glycine, L-ornithine and L-lysine for the studied systems. This trend of 2 indicates solute-solvent interactions increase with increasing concentration of amino acids. The sound velocity increases with the increase of concentration of L-lysine, L-ornithine and glycine. This may be attributed to the increase of compactness of the medium with the increase in amino acids concentration. Sound velocities of L-lysine, L-ornithine and glycine in aqueous fructose solutions are higher than that of L-lysine, L-ornithine and glycine in aqueous solution. The adiabatic compressibility (βs) decreases with the increase of concentration of L-lysine, L-ornithine and glycine. This indicates the water molecules around the amino acids are less compressible than the water molecules in the bulk solution. The negative apparent molar adiabatic compressibility (k) values indicate the greater loss of structural compressibility of water. The values of limiting apparent molar adiabatic compressibility (φk 0) are negative. The values of apparent molar adiabatic compressibility transfer (Δtrφk 0) are positive which suggest the existence of strong solute-solvent interaction. At lower concentration, negative values of Δtrφk 0 indicate that increase in hydrophobic-hydrophobic group interactions. The small Sk values also indicates the dominating of solute-solvent interactions over solute-solute interaction. The acoustic impedance, Z increases with the increase of concentration of amino acids. The relative association, RA decreases linearly with increasing the concentration of solute. The positive hydration number (nH) values indicate an appreciable solvation of solutes. Therefore, the water molecules around amino acids are less compressible than water molecules in the bulk solution. The compressibility of ternary solution is lower than binary solution. This result suggests that the proteins or peptides generated from the studied amino acids will be denatured in ternary fructose solution.
Studies on Volumetric and Ultrasonic Properties of L-Lysine, L-Ornithine and Glycine in Aqueous Fructose Solution at Different Temperatures
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-03) Tariquzzaman, Md.
In this study, the interaction of amino acids (glycine, L-ornithine and L-lysine) in water and aqueous fructose solution has been determined by using volumetric and sound velocity method. Interactions of glycine, L-ornithine and L-lysine in aqueous fructose solution play an important role to understand biochemical process in living cells. Densities and sound velocities of glycine, L-ornithine and L-lysine in water and in aqueous 0.05 mol.kg , 0.20 mol.kg -1 , 0.35 mol.kg -1 and 0.50 mol.kg -1 fructose solutions have been studied at 293.15K to 318.15K with an interval of 5K. The density data have been used to calculate apparent molar volume (φ v ), limiting apparent molar volume (φ v 0 ), limiting apparent molar volume transfer (Δ tr φ v 0 ), apparent molar expansibilities (δφ v 0 /δT) and Hepler’s constant (δ2φv0/δT2)p. The acoustic properties such as adiabatic compressibility (βp), apparent molaradiabatic compressibility (ks), limiting apparent molar adiabatic compressibility (φ),apparent molar adiabatic compressibility of transfer (Δtrφk0), acoustic impedance (Z),relative association (RA) and hydration number (n) have been calculated by densities and sound velocities data. The densities increase with the increase of concentration of amino acids (glycine,L-ornithine and L-lysine). Densities of glycine, L-ornithine and L-lysine in aqueous fructose solutions are higher than that of glycine, L-ornithine and L-lysine in aqueous solution. The smaller values of experimental slope (S ) as compared to limiting apparent molar volume (φ v 0v) values suggest the dominance of solute-solvent interaction over the solute-solute interaction. The true volume (φ v0) of amino acids are found to be order of L-lysine > L-ornithine > glycine. The limiting apparent molar volume transfer (Δtrφv0) values of glycine, L-ornithine and L-lysine are positive which suggest the dominance of ion-hydrophilic and hydrophilichydrophilic interactions over the hydrophobic-hydrophobic and ion-hydrophobic interaction. The values of limiting apparent molar expansion (δφ v0/δT) are positive. Hepler’s constant (δ2φv0/δT2) values are small negative for all studied amino acids in binary and ternary system suggest the studied systems act as structure maker. The values of partial molar volumes (p2p) increase with increasing of concentration of glycine,-1k0L-ornithine and L-lysine for the studied systems. This trend of indicates solute-solvent interactions increase with increasing concentration of amino acids. vi 2 The sound velocity increases with the increase of concentration of L-lysine, L-ornithine and glycine. This may be attributed to the increase of compactness of the medium with the increase in amino acids concentration. Sound velocities of L-lysine, L-ornithine and glycine in aqueous fructose solutions are higher than that of L-lysine, L-ornithine and glycine in aqueous solution. The adiabatic compressibility (β ) decreases with the increase of concentration of L-lysine, L-ornithine and glycine. This indicates the water molecules around the amino acids are less compressible than the water molecules in the bulk solution. The negative apparent molar adiabatic compressibility (ks) values indicate the greater loss of structural compressibility of water. The values of limiting apparent molar adiabatic compressibility (φk0) are negative. The values of apparent molar adiabatic compressibility transfer (Δtrφk0) are positive which suggest the existence of strong solute-solvent interaction. At lower concentration, negative values of Δtrφk0 indicate that increase in hydrophobic-hydrophobic group interactions. The small S values also indicates the dominating of solute-solvent interactions over solute-solute interaction. The acoustic impedance, Z increases with the increase of concentration of amino acids. The relative association, RAk decreases linearly with increasing the concentration of solute. The positive hydration number (n ) values indicate an appreciable solvation of solutes. Therefore, the water molecules around amino acids are less compressible than water molecules in the bulk solution. The compressibility of ternary solution is lower than binary solution. This result suggests that the proteins or peptides generated from the studied amino acids will be denatured in ternary fructose solution.
Study on the accessibility of proposed metro stations in CBD areas of Dhaka city in relation to the spatial structure of local urban grid
(Department of Architecture, BUET, 2019-09-28) Tariquzzaman, Md.; Nilufar, Dr Farida
Accessibility is an important influencing factor for the efficient functioning of a metro system. Among multifaceted metro accessibility indicators such as connectivity, land use mix and diversity, compact and centeredness, attractive walking environment, social norm and cultural preferences, activity locations, trip duration and affordability this research has mainly concentrated upon spatial connectivity of the street network to assess the accessibility condition of the proposed metro stations in CBD context of Dhaka city. Therefore, in a living context, it is a technical challenge to set a strategic location of a metro station considering the spatial network of the local urban grid and movement pattern. Successful integration of a metro station needs to consider those movement and land uses in relation to the local spatial structure particularly in CBD areas where land value and pedestrian movement is extremely high. At the early stage planning, accessibility pattern of the local street network plays a significant role in deciding the accessible location of a metro station which facilitates the efficient transfer of passengers to local destination. However, this study has tried to analyze the configurational characteristics (both Axial and VGA properties) of the local street network to interpret the accessible location of the proposed metro station in the study area of Motijheel and Karwanbazar along the MRT Line-06 route. Space syntax method has been used here as a decision-making tool to investigate the accessibility pattern of the local spatial structure in relation to movement and land uses. For local movement study ‘Gate method’ has been used here. Therefore, from the spatial analysis and field observation the study findings can be summarized in two notes. Firstly, the spatial analysis (both Axial and VGA analysis) of the local urban grid in relation to local movement pattern represents that the interpretation of accessible spaces is more correspondence to the VGA properties than axial properties. Secondly, the accessibility of the proposed metro station depends on how it is connected to the local urban grid where land use pattern plays a significant role to generate movement. For both CBD areas, land use acts as an independent attractor to generate significant movement and creates a multiplier effect when aligned with highly integrated lines. Hence, it requires a further detail investigation in this regard. Finally, based on the field observation and configurational analysis the study findings suggest some guidelines to improve the accessibility condition around the proposed station and manage a mass movement. Therefore, the study contributes to this perspective to analyze the accessibility of the proposed metro station in a living context thus will assist in early-stage planning and design process in determining the accessible location. Key words Metro Station Accessibility, Spatial Connectivity, Space Syntax Method, Central Business District (CBD), Pedestrian Movement and Land use
Study on walkability for sustainable development in central business district Motijheel, Dhaka
(Department of Architecture (Arch), BUET, 2023-04-15) Badhan, Ishrat Momtaz; Tariquzzaman, Md.
'Walkability' within the urban context is one of the prime issues for a sustainable city. In the context of Bangladesh, walkability is considered a fundamental factor for sustainable urban development as per rule. But the strategic measures here are limited only to a few paragraphs and are not context specific. Still, the standing guidelines in Bangladesh conferring on the existing user demand have not been followed practically in most cases. The Motijheel, Dhaka's core business center, where the city's walkability is gravely endangered, exhibits little distinction from the rest. Though a substantial share of users prefers to walk for daily transit, regrettably, a lack of adequate infrastructure, discontinuity, surface deformation, and obstructions creates a greater inefficiency in the walkable context. The walkability agenda regarding sustainable development constitutes the parameters of physical features, legibility, and individual perceptions. Among these, this research concentrated on investigating the physical attributes concerning the user's experience to explore the current walkability situation. However, retrofitting the walkable network within the built-up area is challenging but not impossible. This research seeks to identify the challenges and suggest strategic means to improve walking condition within the living commercial CBD context to aid sustainable urban design and alleviate related problems in other local contexts. A Case Study Research approach including Quantitative and Qualitative analysis has been used here. The level of service (LOS) and sidewalk condition index (SCI) analyses were utilized as a quantitative assessment technique to determine if the Motijheel CBD is sufficiently walkable considering the growing number of pedestrian traffic. As a qualitative assessment technique, questionnaire analysis is considered to investigate the public experience mixed with pedestrian activity. Findings show that, according to the quantitative analysis of Level of Service (LOS), 87% of available walking segments are extremely crowded and incompatible with the volume of regular users. The qualitative survey results are then combined with the observational evaluation for the SCI analysis, resulting in highly obstructed walking circumstances. Among different aspects, the disorganized retail industry (40%) and informal parking (29%) with uneven surfaces (18%) are the major obstructions endangering the current walkability in the study area. Based on these findings, this research suggests the idea of hawking free wide walkways for 53.34% of primary roads to avoid congestion and enhance the walkability of this CBD area. In addition, 33.34% of streets are recommended for being shared walkable spaces with vending activities for prioritizing walkability considering local regulations.