1,721,739 research outputs found
Cosine Similarity Estimation Using FracMinHash: Theoretical Analysis, Safety Conditions, and Implementation
Full text linkMotivation. The increasing number and volume of genomic and metagenomic data necessitates scalable and robust computational models for precise analysis. Sketching techniques utilizing k-mers from a biological sample have proven to be useful for large-scale analyses. In recent years, FracMinHash has emerged as a popular sketching technique and has been used in several useful applications. Recent studies on FracMinHash proved unbiased estimators for the containment and Jaccard indices. However, theoretical investigations for other metrics, such as the cosine similarity, are still lacking.
Theoretical contributions. In this paper, we present a theoretical framework for estimating cosine similarity from FracMinHash sketches. We establish conditions under which this estimation is sound, and recommend a minimum scale factor s for accurate results. Experimental evidence supports our theoretical findings.
Practical contributions. We also present frac-kmc, a fast and efficient FracMinHash sketch generator program. frac-kmc is the fastest known FracMinHash sketch generator, delivering accurate and precise results for cosine similarity estimation on real data. We show that by computing FracMinHash sketches using frac-kmc, we can estimate pairwise cosine similarity speedily and accurately on real data. frac-kmc is freely available here: https://github.com/KoslickiLab/frac-kmc/
sj-docx-1-jir-10.1177_00221856211063924 - Supplemental material for After Rana Plaza: Governing Exploitative Workplace Labour Regimes in Bangladeshi Garment Export Factories
No full textSupplemental material, sj-docx-1-jir-10.1177_00221856211063924 for After Rana Plaza: Governing Exploitative Workplace Labour Regimes in Bangladeshi Garment Export Factories by Stephen J Frenkel, Shahidur Rahman and Kazi Mahmudur Rahman in Journal of Industrial Relations</p
sj-docx-1-jtr-10.1177_00472875221129251 – Supplemental material for Measuring Tourist Festival Experience: Development and Validation of the PHF-TX Model
No full textSupplemental material, sj-docx-1-jtr-10.1177_00472875221129251 for Measuring Tourist Festival Experience: Development and Validation of the PHF-TX Model by Lizette Olivier, Jamie Carlson, Syed Mahmudur Rahman and Philip J. Rosenberger in Journal of Travel Research</p
Pid-aco vibration controller with magnetorheological damper for wind turbine tower / Mahmudur Rahman
Full text linkVibration in the wind turbine tower disturbs the reliability and increase the possibility of structural damage. Therefore, researchers are very attracted to find suitable solution to minimize vibration in wind turbine tower. Two common vibration control approaches, i.e. passive and active control have the limitations to adapt low frequency, varying loading, and frequency conditions vibrations. It is thus resulted in high external energy consumption in supplying controllable current. Previous studies showed that different controllers for wind turbine vibration control are less effective when the frequency or type of disturbances vary and thus require several tuning processes. In addition, previous research works suggested that it is less effective in vibration reduction when the damper is installed at the top or at the bottom of the tower. Therefore, this research proposes a semi-active vibration control approach for wind turbine tower with optimal tuning of proportional integral derivative (PID) through ant colony optimization (ACO) algorithm and by installing a magnetorheological (MR) damper at the mid-point of the tower to overcome the limitations mentioned above. At first, appropriate dynamic model is estimated using finite difference method (FDM) and system identification process. The FDM dynamic model is found 100% fit to estimated data with reasonably good value of mean squared error (MSE) and Cross Signature Assurance Criterion (CSAC). Next, PID control parameters are optimized with ACO method based on the vibration displacement as objective function to achieve the optimal damping force which is used to encounter vibrations under different excitation frequencies and loading conditions. The placement of MR damper on the tower is then investigated to ensure structural balance and vibration mitigation at all points of the wind turbine tower. It is found that wind turbine tower vibration is reduced up 72% when the damper is placed at middle of the tower and the selection of this optimal location is also based on considerations such as design complexity and maintenance cost. When the proposed optimized PID-ACO controller is tested under different excitations frequencies and loading conditions, results show that the semi-active PID-ACO controller reduces the tower vibration up to 83% and 68% under harmonics excitation at tower 1st mode and random disturbances respectively without the needs of re-tuning the PID parameters. This is effective in preventing structural damage of the wind turbine tower due to unexpected disturbances. This research validates the simulation results with real implementation of lab-scaled wind turbine tower under various loadings such as harmonics excitation at tower 1st mode, sweep frequencies, and random excitations under four damping environments, 1) without damper, 2) passive damper, (i.e. 0 ampere current to MR damper), 3) optimal input current to MR damper, and 4) Locked state, (i.e. high input current to MR damper). It is observed that the real implementation semi-active PID-ACO control system with MR damper reduces up to 73% and 40% of vibration displacement under harmonics excitation at tower 1st mode and random disturbances respectively
Factors contributing the outcome of Schizophrenia in developing and developed countries: A brief review
No full textAbstractAccording to WHO,schizophrenia is a severe form of mental illness affecting about 7 per thousandof the adult population, mostly in the age group 15-35 years. Though theincidence is low (3-10,000), the prevalence is high due to chronicity. Schizophrenia is occurring in both developingand developed countries.The remission rate is higher in developing countries compared to the developedones. There are some compelling factors that may influence the outcome ofschizophrenia includes gender, employment, marital status, family support,illness myths, family burden, duration of untreated psychosis etc. In this review we have discussed the epidemiology,pathophysiology, diagnosis, treatment and finally the factors that influencethe outcome of schizophrenia in developing and developed countries.
Mahmudur Rahman
B. Pharm. (Hons.), M. Pharm (Thesis), M.Sc. in Pharm (Thesis), RegPharmBDPhD Student
Southern Cross Plant Science | Southern Cross University
Lismore, NSW 2480, Australia
http://scu.edu.au/scps/index.php/166Assistant Professor (on leave),Department of Pharmacy.
Northern University Bangladesh.
24, Mirpur Road, Globe Centre, Dhaka-1205, Bangladesh.http://www.nub.ac.bd/pims/faculty-member/mr28vw4a/mr.-mahmudur-rahmanURL: https://www.researchgate.net/profile/Mahmudur_Rahman3?hl=enhttps://scholar.google.com./citations?hl=en&user=17qL1a8AAAAJ
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Factors contributing the outcome of Schizophrenia in developing and developed countries: A brief review
No full textAbstractAccording to WHO,schizophrenia is a severe form of mental illness affecting about 7 per thousandof the adult population, mostly in the age group 15-35 years. Though theincidence is low (3-10,000), the prevalence is high due to chronicity. Schizophrenia is occurring in both developingand developed countries.The remission rate is higher in developing countries compared to the developedones. There are some compelling factors that may influence the outcome ofschizophrenia includes gender, employment, marital status, family support,illness myths, family burden, duration of untreated psychosis etc. In this review we have discussed the epidemiology,pathophysiology, diagnosis, treatment and finally the factors that influencethe outcome of schizophrenia in developing and developed countries.
Mahmudur Rahman
B. Pharm. (Hons.), M. Pharm (Thesis), M.Sc. in Pharm (Thesis), RegPharmBDPhD Student
Southern Cross Plant Science | Southern Cross University
Lismore, NSW 2480, Australia
http://scu.edu.au/scps/index.php/166Assistant Professor (on leave),Department of Pharmacy.
Northern University Bangladesh.
24, Mirpur Road, Globe Centre, Dhaka-1205, Bangladesh.http://www.nub.ac.bd/pims/faculty-member/mr28vw4a/mr.-mahmudur-rahmanURL: https://www.researchgate.net/profile/Mahmudur_Rahman3?hl=enhttps://scholar.google.com./citations?hl=en&user=17qL1a8AAAAJ
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Concepts in de-watering using tube wells
No full textNarrators: Mahmudur Rahman and Nima RahmanTubewells are used in Bangladesh to pump excess groundwater from water-logged land, in a process called dewatering
Preoperative angular insertion depth prediction in case of lateral wall cochlear implant electrode arrays
No full textModelling individuals’ longer-term preferences towards autonomous vehicles and their effects on vehicle ownership
No full textAutonomous vehicle (AV) promises to change the transportation landscape such as reducing traffic congestion and emissions. The success of this emerging technology largely depends on how individuals will adopt it. This thesis investigates individuals’ longer-term preferences for AVs, and their effects on vehicle ownership, specifically focusing on the preferences towards different levels of vehicle automation, AV ownership (AVO) and AV sharing (SAV), and vehicle transaction decisions in an AV future. A life history-oriented approach is adopted to examine the effects of historical experiences and changes over the life course, such as historical exposure to technology, the evolution of household characteristics, vehicle ownership history, historical measures of accessibility and built-environment on AV adoption. In addition, variables representing attitudinal factors, travel attributes, and socio-demographics are accommodated in the study. Data for the thesis comes from the retrospective survey conducted for the Okanagan region of British Columbia. In the case of preferences for different levels of vehicle automation, a random parameter rank-ordered logit model is developed to accommodate rank-ordered preferences for vehicular automation levels and capture unobserved heterogeneity. For preferences towards AVO and SAV, a joint bivariate ordered probit model is developed to address the error correlation between decisions. The study confirms that a significant error correlation exists, which indicates that the unobserved factors jointly affect the choice alternatives. A latent class random parameter logit modelling technique is utilized to capture heterogeneity while modelling vehicle transaction decisions in the AV future. The model results confirm the existence of historical deposition effects on individuals’ preferences towards AVs. For example, individuals with historical exposure to vehicle technology, such as availability of lane assist, parking assist, and autonomous emergency stop, have a higher likelihood of adopting higher levels of vehicle automation. Besides, they are more likely to add AV to the current vehicle fleet. Similarly, the AVO and SAV model results suggest that individuals with a higher number of smartphone ownership over the life course are more likely to adopt both. The model results also confirm the existence of heterogeneity. Overall, the findings of the study provide important behavioural insights and have significant policy implications that might be used for targeted marketing to promote AVs.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat
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