Browsing by Author "Ullah, Md. Habib"

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An Advanced and Secure Framework for Conducting Online Examination Using Blockchain Method
(Elsevier, 2022-08-11) Sattar, Md Rahat Ibne; Efty, Md. Thowhid Bin Hossain; Rafa, Taiyaba Shadaka; Das, Tusar; Samad, Md Sharif; Pathak, Abhijit; Khandaker, Mayeen Uddin; Ullah, Md. Habib
Nowadays, the online platform has been used by many educational institutions, to conduct tests, especially for secondary to tertiary level students. The most popular online test program is run by providing a user id and password to the candidates, and subsequently, they log in to the given web page to answer the questions. However, this system has a lot of bugs, the password can be misused followed by cheating in the test. This shows the importance of a secure system being implemented to avoid such a problem. This paper presents a blockchain framework that secures the online examination system. The proposed framework has been used to secure a data management system that connects to existing educational data. Institutions can simply compile their data history without requiring a copy from the central servers. The proposed blockchain framework improves data security and removes any potential cheating between users or third-party institutions that access applications and services. In this regard, this study provides a secured framework for conducting and evaluating subject tests to ensure consistency between student and server, and secure delivery of questionnaire from the server.
Blended Learning Pedagogy and Its Implementation in the Tertiary Education: Bangladesh Perspectives
(Frontier Scientific Publishing, 2023-08-15) Mitra, Shrabonti; Malek, Md. Abdul; Sultana, Tanzin; Pathak, Abhijit; Abedin, Md. Jainal; Kobra, Khadizatul; Ullah, Md. Habib; Khandake, Mayeen Uddin
This paper reviews the theoretical foundations and components of blended learning (BL) in higher education globally, analyzing six articles from five countries published between January 2016 and December 2020. The study identified challenges faced by instructors, including workload, timeliness, and lack of academic and technical skills to manage BL. Balancing face-to-face and online learning was also challenging. To address these issues, the importance of staff training, support, and networking was emphasized, proposing a modified BL model for tertiary education in Bangladesh, which could be implemented post-pandemic using a machine-learning approach. The mixed BL model was recommended for Bangladeshi institutions, utilizing machine learning algorithms to facilitate outcome-based learning through technological applications. A preliminary survey of 120 students from BGC Trust University in Bangladesh was conducted using statistical data obtained from machine learning algorithms to explore the applicability of the mixed-learning approach. Machine learning proved beneficial for data analysis, drawing valuable insights for educators and policymakers seeking effective teaching strategies that incorporate technology. This research underscores the potential of machine learning in conducting surveys and analyzing data related to blended learning in tertiary education, offering significant contributions to the field.
Perovskite materials in X-ray detection and imaging: recent progress, challenges, and future prospects
(2024-06-15) Miah, Md. Helal; Khandaker, Mayeen Uddin; Aminul Islam, Mohammad; Nur-E-Alam, Mohammad; Osman, Hamid; Ullah, Md. Habib
Perovskite materials have attracted significant attention as innovative and efficient X-ray detectors owing to their unique properties compared to traditional X-ray detectors. Herein, chronologically, we present an in-depth analysis of X-ray detection technologies employing organic–inorganic hybrids (OIHs), all-inorganic and lead-free perovskite material-based single crystals (SCs), thin/thick films and wafers. Particularly, this review systematically scrutinizes the advancement of the diverse synthesis methods, structural modifications, and device architectures exploited to enhance the radiation sensing performance. In addition, a critical analysis of the crucial factors affecting the performance of the devices is also provided. Our findings revealed that the improvement from single crystallization techniques dominated the film and wafer growth techniques. The probable reason for this is that SC-based devices display a lower trap density, higher resistivity, large carrier mobility and lifetime compared to film- and wafer-based devices. Ultimately, devices with SCs showed outstanding sensitivity and the lowest detectable dose rate (LDDR). These results are superior to some traditional X-ray detectors such as amorphous selenium and CZT. In addition, the limited performance of film-based devices is attributed to the defect formation in the bulk film, surfaces, and grain boundaries. However, wafer-based devices showed the worst performance because of the formation of voids, which impede the movement of charge carriers. We also observed that by performing structural modification, various research groups achieved high-performance devices together with stability. Finally, by fusing the findings from diverse research works, we provide a valuable resource for researchers in the field of X-ray detection, imaging and materials science. Ultimately, this review will serve as a roadmap for directing the difficulties associated with perovskite materials in X-ray detection and imaging, proposing insights into the recent status, challenges, and promising directions for future research.
Perovskite Materials in X-ray Detection and Imaging: Recent Progress, Challenges, and Future Prospects
(The Royal Society of Chemistry, 2024-02-22) Miah, Md. Helal; Khandaker, Mayeen Uddin; Islam, Mohammad Aminul; Nur-E-Alam, Mohammad; Osman, Hamid; Ullah, Md. Habib
Perovskite materials have attracted significant attention as innovative and efficient X-ray detectors owing to their unique properties compared to traditional X-ray detectors. Herein, chronologically, we present an in-depth analysis of X-ray detection technologies employing organic–inorganic hybrids (OIHs), all-inorganic and lead-free perovskite material-based single crystals (SCs), thin/thick films and wafers. Particularly, this review systematically scrutinizes the advancement of the diverse synthesis methods, structural modifications, and device architectures exploited to enhance the radiation sensing performance. In addition, a critical analysis of the crucial factors affecting the performance of the devices is also provided. Our findings revealed that the improvement from single crystallization techniques dominated the film and wafer growth techniques. The probable reason for this is that SC-based devices display a lower trap density, higher resistivity, large carrier mobility and lifetime compared to film- and wafer-based devices. Ultimately, devices with SCs showed outstanding sensitivity and the lowest detectable dose rate (LDDR). These results are superior to some traditional X-ray detectors such as amorphous selenium and CZT. In addition, the limited performance of film-based devices is attributed to the defect formation in the bulk film, surfaces, and grain boundaries. However, wafer-based devices showed the worst performance because of the formation of voids, which impede the movement of charge carriers. We also observed that by performing structural modification, various research groups achieved high-performance devices together with stability. Finally, by fusing the findings from diverse research works, we provide a valuable resource for researchers in the field of X-ray detection, imaging and materials science. Ultimately, this review will serve as a roadmap for directing the difficulties associated with perovskite materials in X-ray detection and imaging, proposing insights into the recent status, challenges, and promising directions for future research.
Tailoring the Properties of Bulk BaTiO3 Based Perovskites by Heteroatom-Doping towards Multifunctional Applications: A Review
(IOP Publishing Limited, 2023-10-27) Rahman, M. Atikur; Hasan, Zahid; Islam, Jahidul; Das, D. K.; Chowdhury, Faisal I.; Khandaker, Mayeen Uddin; Zabed, Hossain M.; Bradley, D. A.; Osman, Hamid; Ullah, Md. Habib
Dielectric barium titanate-based perovskite (BaTiO3) has emerged as one of the most popular multilayer ceramic materials for its versatile properties. However, the intrinsic properties, particularly the dielectric, ferroelectric, piezoelectric, and electrical properties of natural barium titanate perovskite (BTP) are not as attractive as required for its multifunctional applications. In recent years, the doping technique has been widely studied for improving the desirable properties of BTP ceramic to expand its practical applications in various advanced technologies. Considering the latest research and developments, this review aims to discuss the synthesis techniques of hetero-atom doped BTP, together with doping status, such as doping sites, doped content, and surface-to-volume ratio. We also critically analyze the effects of co-factors (e.g., sintering temperature, grain size, Curie temperature, and compositions of hetero-atoms) on the structural, and electronic properties of BTP. In addition, optimization of the doping requirements for obtaining the desired improvements of the target properties is also discussed, coupled with providing a comprehensive discussion on the synthesis pathways. Subsequently, diverse applications of the heteroatom-doped BTP are exemplified. Finally, major challenges and future outlooks are highlighted from the perspective of different applications of BTP.