Abdullah Al Mamun - Academia.edu (original) (raw)

Papers by Abdullah Al Mamun

International Journal of Environmental Research and Public Health, 2021

Previous studies on internet use frequency were focused on mental health impact, with little know... more Previous studies on internet use frequency were focused on mental health impact, with little known about the impact on physical health during the COVID-19 lockdown. This study examined the impact of internet use frequency on self-reported physical health during the COVID-19 lockdown in Bangladesh. A web-based cross-sectional study on 3242 individuals was conducted from 2 August–1 October 2020. The survey covered demographics, internet use frequency and self-reported physical health questions. Linear regression analyses were used to examine the impact of internet use frequency on physical health. 72.5%, 69.9%, 65.1% and 55.3% respondents reported headache, back pain, numbness of the fingers and neck pain, respectively. The analyses showed increased physical health impact among regular (coefficient β = 0.52, 95% confidence interval [CI]: 0.18–0.85, p = 0.003), frequent (β = 1.21, 95% CI: 0.88–1.54, p < 0.001) and intense (β = 2.24, 95% CI: 1.91–2.57, p < 0.001) internet users. O...

SAE International Journal of Alternative Powertrains, 2018

This article investigates the fuel savings potential of a series hybrid military truck using a si... more This article investigates the fuel savings potential of a series hybrid military truck using a simultaneous battery pack design and powertrain supervisory control optimization algorithm. The design optimization refers to the sizing of the lithium-ion battery pack in the hybrid configuration. The powertrain supervisory control optimization determines the most efficient way to split the power demand between the battery pack and the engine. Despite the available design and control optimization techniques, a generalized mathematical formulation and solution approach for combined design and control optimization is still missing in the literature. This article intends to fill that void by proposing a unified framework to simultaneously optimize both the battery pack size and power split control sequence. This is achieved through a combination of genetic algorithm (GA) and Pontryagin's minimum principle (PMP) where the design parameters are integrated into the Hamiltonian function. As GA and PMP are global optimization methodologies under suitable conditions, the solution can be considered as a benchmark for the application under study. Five military drive cycles are used to evaluate the proposed approach. The simulation results show 5%-19% reduction in fuel consumption depending on the drive cycle compared to a baseline non-optimized case.

Mediterranean Journal of Social Sciences, 2016

Entrepreneurship is regarded as one of the key economic development strategies to advance a count... more Entrepreneurship is regarded as one of the key economic development strategies to advance a country's economic growth and to sustain its competitiveness in facing the increasing trends of globalization. The Malaysian government has made tremendous efforts in promoting entrepreneurship education across the country. This paper therefore aims to review the programs and policies, together with empirical studies on entrepreneurial education, and its effects on students' entrepreneurial intentions. Finally, the review of the policies and practices in Malaysia shows that the government is mostly focused on the following aspects: improving the current policy on entrepreneurship education, providing various entrepreneurship programs to increase the number of young entrepreneurs, and highlighting the need to empower entrepreneurship education among graduates of HEIs.

Mediterranean Journal of Social Sciences, 2015

The objective of this study is to determine the distribution of social capital across industries ... more The objective of this study is to determine the distribution of social capital across industries and states in Peninsular Malaysia, since social capital is considered one of the key factors that contribute to the performance of micro-enterprises. This study employs the cross-sectional approach and quantitative data were collected through structured interviews from 417 women micro-entrepreneurs in Peninsular Malaysia. It was found that the distribution of social capital is the same across industries except for 'shared meaning and interpretation' and 'cognitive social capital'. However, findings reported a significant difference in items of social capital among the states, except for 'network density'. Policy makers should therefore focus on interactive programs in order to increase the social capital of the states with a low level of social capital as social capital is linked to enterprise performance and economic development.

International Journal of Control, Automation and Systems, 2015

ABSTRACT Mechanical resonant modes of the actuator severely impede the efforts in achieving high ... more ABSTRACT Mechanical resonant modes of the actuator severely impede the efforts in achieving high precision in head positioning servo system of hard disk drives (HDD). Hence it is important that these modes be properly compensated. The conventional approach is to use a notch filter in cascade with the nominal controller, which works well if the resonant frequencies are known and do not vary during operation. However, in reality, frequency and damping ratio of the resonant modes vary in massproduced systems. They also get changed over time due to wear and tear. As a result, auto-tuning or adaptation of the notch filters is required to maintain the performance at the same level. In this paper, a discrete time adaptive controller is presented in a simple and yet efficient way to suppress the effects of resonant modes. Effectiveness of the proposed compensator is demonstrated through simulation and experiments by implementing the compensator for a Voice Coil Motor (VCM) actuator used in HDD.

BMC Public Health, 2015

Background: Although cigarette smoking affects all biological systems of the human body including... more Background: Although cigarette smoking affects all biological systems of the human body including the gastrointestinal tract, there is a lack of evidence regarding its effect on the severity of diarrhoeal disease and whether a dose-response relationship exists. We therefore tested for the presence of specific causative pathogens for infectious diarrhoea, assessed the independent effect of smoking on its severity and tested whether any dose-response relationship existed while controlling for subjects' age, sociodemographic characteristics and presence of causative pathogens in an urban setting in Bangladesh. Methods: A total of 20,757 patients aged 15 years and above with diarrhoea were enrolled into the Diarrhoeal Disease Surveillance System, managed by the International Centre for Diarrhoeal Disease Research, Bangladesh, from 1993 to 2012. We collected data on individuals' current daily consumption of cigarettes and bidis (traditional hand-rolled cigarettes) and conducted an ordered logistic regression to determine the effect of smoking on diarrhoeal disease severity and whether a dose-response relationship exists. Results: We identified 19 % of patients with diarrhoea as smokers, of whom 52 % smoked 1-9 cigarettes per day. While 97 % of smokers were male, 41 % were aged 15-30 years of age. Smokers were found to have a significantly lower severity of diarrhoeal disease (OR: 0.92, 95 % CI: 0.85-0.99, p = 0.025) after adjusting for age, wealth quintile, illiteracy and the presence of specific causative pathogens (Vibrio cholerae and Shigella). We observed no dose-response relationship between the number of cigarettes smoked per day and disease severity when adjusting for the same covariates. Smokers were more frequently infected with Shigella (7 vs. 6 %, p < 0.001) and less often with Vibrio cholerae (22 vs. 26 %, p < 0.001) than their non-smoking counterparts. Conclusions: The aetiology and severity of diarrhoeal disease differed between smokers and non-smokers in our sample. However, we found no dose-response relationship between disease severity and the number of cigarettes smoked per day.

Lecture Notes in Computer Science, 2014

Independent Component Analysis (ICA) has been widely used for separating artifacts from Electroen... more Independent Component Analysis (ICA) has been widely used for separating artifacts from Electroencephalographic (EEG) signals. Still, a few challenging problems remain. First, in real-time applications, visual inspection of components should be replaced with an automatic identification method or a heuristic for artifacts detection. Second, as we will explain more in the paper, we expect to have a clear order relationship between an electrode and a corresponding component. Third, we need to minimize the EEG information loss during artifact removal while also minimizing the residue of the artifact in the cleaned signal. In this paper, we propose a decomposition of the independent components. This decomposition separates each component into two vectors, one-we call local vector-maintains maximum information from the unique EEG information encoded by an electrode, while the other-we call shared vector-absorbs overlapping artifact information. We present an explicit Pareto-based multi-objective optimization formulation that trade-off similarity between the local vector and the original vector on the one hand, and the uncorrelatedness of all local vectors from all components on the other hand. We demonstrate that the proposed method can automatically isolate artifacts from an EEG signal while preserving maximum EEG information.

2006 IEEE International Conference on Robotics and Biomimetics, 2006

The Gyrobot is a gyroscopically stabilized, single-wheeled robot. A fast spinning flywheel mounte... more The Gyrobot is a gyroscopically stabilized, single-wheeled robot. A fast spinning flywheel mounted inside the frame provides lateral stability of the wheel-shaped robot. Steering of the robot is effectuated by tilting the flywheel with the help of a tilt motor, and forward/backward motion is implemented by another motor mounted on the heavy platform. This structure of robot shows excellent dynamic stability and is, therefore, suitable for navigation in unknown, rough terrain. From this point of view, the Gyrobot has definite advantage over other types of wheeled robots. Moreover, the electronic components are placed inside the sealed shell of the wheel giving it an advantage in operations where navigation in wet surfaces is required, for example inspection of sewerage lines or chemical spills. In this paper, we report the design and fabrication of the Gyrobot and present the results of path following navigating algorithm designed for this robot. A linear feedback controller is adopted at this stage to control the tilt and forward/backward motion of the robot.

8th International Conference on Electrical and Computer Engineering, 2014

This paper briefly presents a stability analysis of interconnected systems with mixed passivity a... more This paper briefly presents a stability analysis of interconnected systems with mixed passivity and negative-imaginary properties in discrete-time. These results are analogous to previously established continuous-time case. As discretization of the system or discrete-time design is an important issue for control system design, this paper provides a base for discretization of “mixed” system with passivity and negative imaginary properties. Numerical example and simulation results demonstrate the effectiveness of the proposed analysis.

Journal of the Bangladesh Association of Young Researchers, 2012

Irrigated agriculture has been playing a vital role for the growth in crop production in Banglade... more Irrigated agriculture has been playing a vital role for the growth in crop production in Bangladesh. Minor irrigation comprising of shallow tubewells (STWs), deep tubewells (DTWs), hand tubewells (HTWs) and low-lift pumps (LLPs) is a major irrigation system in the country. Poor performance of irrigation is an issue for the expansion of irrigated area. The present study was carried out to examine the conveyance efficiency and rate of irrigation water loss in DTW schemes in Bogra, Thakurgaon and Godagari zones of Barind Management Development Authority. There were various types of water distribution identified in these schemes with including Poly Venyl Chloride (PVC) buried pipe, cement concrete (CC) rectangular, Ferro trapezoidal, Ferro semicircular and rectangular earth drain. The average conveyance efficiency of PVC buried pipe for Bogra, Thakurgaon and Godagari zones ranged from 94.46% to 95.37% and rate of water loss ranged from 5.45% to 9.55% in three study zones. Average convey...

Chemosphere, 2015

h i g h l i g h t s Water, hair and nail arsenic showed unique associations with serum VEGF level... more h i g h l i g h t s Water, hair and nail arsenic showed unique associations with serum VEGF levels. Arsenic exposure showed precise nature of dose-response relationship with VEGF levels. All the observed associations were significant after adjusting with relevant covariates. Increased serum VEGF may cause angiogenesis for arsenic-induced cancers and CVD.

Communications in Computer and Information Science, 2010

... 1. Saleh, T., Yap, HH, Al-Mamun, A., Zhen, Z., Vadakkepat, P.: Design of a gyroscopically sta... more ... 1. Saleh, T., Yap, HH, Al-Mamun, A., Zhen, Z., Vadakkepat, P.: Design of a gyroscopically stabilized single-wheeled robot. In: IEEE Conference on Robotics, Automation and Mechatronics, pp. 904908 (2004) 2. Brown, HB, Xu, Y.: A single wheel gyroscopically stabilized robot. ...

2012 International Conference on Informatics, Electronics & Vision (ICIEV), 2012

The line follower is an autonomous robot that detects and follows a line. The path may be visible... more The line follower is an autonomous robot that detects and follows a line. The path may be visible like a black line on a white surface or may be reverse of that or it can be invisible like a magnetic field. A close loop control system is used in the robot. The robot must sense a line and maneuvers accordingly to stay on course while correcting the wrong moves using feedback mechanism thus forming a simple but yet effective closed loop System [I]. The robot is designed to follow very tight curves as the data from the sensors are continuous in nature. This robot is simple but effective having straightforward design to perform line following task.

SSRN Electronic Journal, 2010

This study employs a cross sectional design with stratified random sampling method to examine the... more This study employs a cross sectional design with stratified random sampling method to examine the effect of Amanah Ikhtiar Malaysia's (AIM) microcredit program on hardcore poor households' microenterprise assets in Peninsular Malaysia. So far no known study has been conducted to measure the effect of AIMs microcredit programs on microenterprise assets owned by hardcore poor households. It is evident that AIM's microcredit program increased microenterprise assets owned by hardcore poor households who received credit from AIM. This program should, therefore, focus on providing adequate training, flexible and diversified loan programs, and increasing outreach. The policy may also be reviewed and reorganized to reduce the dropout rate.

Journal of Medicine, 2008

DOI = 10.3329/jom.v7i2.1368 J MEDICINE 2006; 7 : 70-72

Tobacco Control, 2006

Objective: To examine the association between maternal smoking during pregnancy and the developme... more Objective: To examine the association between maternal smoking during pregnancy and the development of smoking behaviour patterns among young adult offspring. Method: Data were from the Mater-University of Queensland Study of Pregnancy (MUSP), a birth cohort of 7223 mothers and children enrolled in Brisbane, Australia, in 1981. The development of smoking behaviours (early or late onset, or combination of onset and prevalence patterns) among offspring at age 21 years with different patterns of maternal smoking (never smoked, smoked before or after pregnancy but not during pregnancy, or smoked during pregnancy) were compared. Maternal smoking information was derived from the prospectively collected data from the beginning of pregnancy until the child was 14 years of age. Analyses were restricted to the 3058 mothers and children whose smoking status was reported. Results: The proportion of young adults who smoked regularly, either with early onset or late onset, was greater among those whose mothers had smoked during pregnancy compared with those whose mothers had never smoked. The smoking patterns among those adolescent offspring whose mothers stopped smoking during pregnancy, but who then smoked at other times during the child's life, were similar to those whose mothers had never smoked. This association was robust to adjustment for a variety of potential covariates. Conclusions: The findings provide some evidence for a direct effect of maternal smoking in utero on the development of smoking behaviour patterns of offspring and provide yet another incentive to persuade pregnant women not to smoke.

Robotics and Autonomous Systems, 2007

It is generally not easy to achieve smooth path planning in an unknown environment for nonholonom... more It is generally not easy to achieve smooth path planning in an unknown environment for nonholonomic mobile robots, which are subject to various robot constraints. In this paper, a hybrid approach is proposed for smooth path planning with global convergence for differential drive nonholonomic robots. We first investigate the use of a polar polynomial curve (PPC) to produce a path changing continuously in curvature and satisfying dynamic constraints. In order to achieve path generation in real-time, a computationally effective method is proposed for collision test of the complex curve. Then, a hybrid path planning approach is presented to guide the robot to move forward along the boundary of an obstacle of arbitrary shape, by generating a proper "Instant Goal" (and a series of deliberate motions through PPC curve based path generation) and planning reactively when needed using a fuzzy controller for wall following. The choice of an Instant Goal is limited to the set of candidates that are practically reachable by the robot and that enable the robot to continue following the obstacle. The effectiveness of the proposed approach is verified by simulation experiments.

Physical Review E, 2009

A dusty electronegative plasma containing Boltzmann electrons, Boltzmann negative ions, cold mobi... more A dusty electronegative plasma containing Boltzmann electrons, Boltzmann negative ions, cold mobile positive ions, and negatively charged stationary dust has been considered. The basic features of arbitrary amplitude solitary waves ͑SWs͒ and double layers ͑DLs͒, which have been found to exist in such a dusty electronegative plasma, have been investigated by the pseudopotential method. The small amplitude limit has also been considered in order to study the small amplitude SWs and DLs analytically. It has been shown that under certain conditions, DLs do not exist, which is in good agreement with the experimental observations of Ghim and Hershkowitz ͓Y.

Pattern Recognition, 2009

The low-dimensional representation of high-dimensional data and the concise description of its in... more The low-dimensional representation of high-dimensional data and the concise description of its intrinsic structures are central problems in data analysis. In this paper, an unsupervised learning algorithm called weighted locally linear embedding (WLLE) is presented to discover the intrinsic structures of data, such as neighborhood relationships, global distributions and clustering. The WLLE algorithm is motivated by locally linear embedding (LLE) algorithm and cam weighted distance, a novel distance measure which usually gives a deflective cam contours for equal-distance contour in classification for an improved classification. It is a major advantage of the WLLE to optimize the process of intrinsic structure discovery by avoiding unreasonable neighbor searching, and at the same time, allow the discovery adapt to the characteristics of input data set. Furthermore, the algorithm discovers intrinsic structures which can be used to compute manipulative embedding for potential classification and recognition purposes, thus can work as a feature extraction algorithm. Simulation studies demonstrate that the WLLE can give better results in manifold learning and dimension reduction than LLE and neighborhood linear embedding (NLE), and is more robust to parameter changes. Experiments on face images data sets and comparison to other famous face recognition methods such as kernel-PCA (KPCA) and kernel direct discriminant analysis (KDDA) are done to show the potential of WLLE for real world problem.

Obesity, 2009

We examined the prospective association of childhood BMI z-score and BMI categories (normal or ov... more We examined the prospective association of childhood BMI z-score and BMI categories (normal or overweight) with young adult diabetes, controlling for early life, childhood, and adolescence factors. A subsample of 2,639 young adults from the Mater-University study of pregnancy (MUSP) and its outcomes, a prospective birth cohort who were born in Brisbane, Australia and for whom we had measured height and weight at 5 years and self-reported diabetes at age 21 years. The risk of developing diabetes by age 21 years was greater among young adults who had greater BMI z-score or were overweight at age 5 years than those who had normal BMI at age 5 years. Young adults who were overweight at age 5 years had an increased odds ratio of 2.60 (95% confidence interval (CI): 1.29, 5.22, in age- and sex-adjusted model) of experiencing diabetes by age 21 years. Adjustment for potential confounders and mediators including intrauterine environmental factors, childhood dietary patterns, television watching, participation in sports and exercise, and current weight, did not substantively alter these associations. Overweight and increasing BMI z-score at childhood is an independent predictor of young adult&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s type 1 and type 2 diabetes. Findings of this study suggest that childhood BMI may be central to the development and rising incidence of all diabetes.