87 research outputs found

    Modelling and Interactional Control of a Multi-fingered Robotic Hand for Grasping and Manipulation.

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    PhDIn this thesis, the synthesis of a grasping and manipulation controller of the Barrett hand, which is an archetypal example of a multi-fingered robotic hand, is investigated in some detail. This synthesis involves not only the dynamic modelling of the robotic hand but also the control of the joint and workspace dynamics as well as the interaction of the hand with object it is grasping and the environment it is operating in. Grasping and manipulation of an object by a robotic hand is always challenging due to the uncertainties, associated with non-linearities of the robot dynamics, unknown location and stiffness parameters of the objects which are not structured in any sense and unknown contact mechanics during the interaction of the hand’s fingers and the object. To address these challenges, the fundamental task is to establish the mathematical model of the robot hand, model the body dynamics of the object and establish the contact mechanics between the hand and the object. A Lagrangian based mathematical model of the Barrett hand is developed for controller implementation. A physical SimMechanics based model of the Barrett hand is also developed in MATLAB/Simulink environment. A computed torque controller and an adaptive sliding model controller are designed for the hand and their performance is assessed both in the joint space and in the workspace. Stability analysis of the controllers are carried out before developing the control laws. The higher order sliding model controllers are developed for the position control assuming that the uncertainties are in place. Also, this controllers enhance the performance by reducing chattering of the control torques applied to the robot hand. A contact model is developed for the Barrett hand as its fingers grasp the object in the operating environment. The contact forces during the simulation of the interaction of the fingers with the object were monitored, for objects with different stiffness values. Position and force based impedance controllers are developed to optimise the contact force. To deal with the unknown stiffness of the environment, adaptation is implemented by identifying the impedance. An evolutionary algorithm is also used to estimate the desired impedance parameters of the dynamics of the coupled robot and compliant object. A Newton-Euler based model is developed for the rigid object body. A grasp map and a hand Jacobian are defined for the Barrett hand grasping an object. A fixed contact model with friction is considered for the grasping and the manipulation control. The compliant dynamics of Barrett hand and object is developed and the control problem is defined in terms of the contact force. An adaptive control framework is developed and implemented for different grasps and manipulation trajectories of the Barrett hand. The adaptive controller is developed in two stages: first, the unknown robot and object dynamics are estimated and second, the contact force is computed from the estimated dynamics. The stability of the controllers is ensured by applying Lyapunov’s direct method

    Smartphone and Our Students: Is It Being Good for Their Study?

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    The objectives of this study are to: (I) find out the discriminations or variations (if any) between the attentive and inattentive university students in terms of their purposes of using smartphones, (II) analyze the cause-effect relationship between “the purposes considered to have good or bad impact on study” and “the smartphone usage behavior of the attentive students”, and (III) analyze the cause-effect relationship between “the purposes considered to have good or bad impact on study” and “the smartphone usage behavior of the inattentive students”. 400 students (200 attentive and 200 inattentive) students are surveyed.  Based survey and statistical analysis results, it is found that attentive and inattentive student are differentiating from each other in terms of their purposes of using smartphones for learning and study, social networking and entertainment. Moreover, the reasons of using smartphones believed to be in favor of their learning activities have positive impact on the attentive students’ smartphones usage behavior, whereas inattentive students are not acting likewise. Corrective actions by the interested parties should be undertaken to reform this unexpected scenario. Keywords: Smartphone, Students, Education, Bangladesh

    Empathy Detection Using Machine Learning on Text, Audiovisual, Audio or Physiological Signals

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    Empathy is a social skill that indicates an individual's ability to understand others. Over the past few years, empathy has drawn attention from various disciplines, including but not limited to Affective Computing, Cognitive Science and Psychology. Empathy is a context-dependent term; thus, detecting or recognising empathy has potential applications in society, healthcare and education. Despite being a broad and overlapping topic, the avenue of empathy detection studies leveraging Machine Learning remains underexplored from a holistic literature perspective. To this end, we systematically collect and screen 801 papers from 10 well-known databases and analyse the selected 54 papers. We group the papers based on input modalities of empathy detection systems, i.e., text, audiovisual, audio and physiological signals. We examine modality-specific pre-processing and network architecture design protocols, popular dataset descriptions and availability details, and evaluation protocols. We further discuss the potential applications, deployment challenges and research gaps in the Affective Computing-based empathy domain, which can facilitate new avenues of exploration. We believe that our work is a stepping stone to developing a privacy-preserving and unbiased empathic system inclusive of culture, diversity and multilingualism that can be deployed in practice to enhance the overall well-being of human life

    Design methodologies for M-health innovations: A content analysis

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    Miah, Gammack, Hasan and Hoque © 2016 authors. Whilst researchers and professionals recognize that M-health offers great opportunities, most existing work has comprised individual project-based developments in specialised areas. Existing review papers generally utilise medical literature and categories: none investigates M-health from an IS design point of view. Identifying application areas, design issues and IS research techniques will demonstrate models, issues, approaches and gaps to inform future research. A comprehensive analysis of up to date literature from this viewpoint is valuable, both for theoretical progression and for guiding real-world innovative developments. Drawing from key IS and multidisciplinary journals we analyse recent (2010-2016) articles concerning M-health application developments and their associated design or development issues. We identify eight application categories, ten design issues (security, privacy, literacy, accessibility, acceptability, reliability, usability, confidentiality, integrity and knowledge sharing) and the stakeholders and development techniques involved. The analysis suggests M-health is an emerging field to which design science is particularly appropriate

    Design methodologies for M-health innovations: a content analysis

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    Whilst researchers and professionals recognize that m-health offers great opportunities, most existing work has comprised individual project-based developments in specialised areas. Existing review papers generally utilise medical literature and categories: none investigates m-health from an IS design point of view. Identifying application areas, design issues and IS research techniques will demonstrate models, issues, approaches and gaps to inform future research. A comprehensive analysis of up to date literature from this viewpoint is valuable, both for theoretical progression and for guiding real-world innovative developments. Drawing from key IS and multidisciplinary journals we analyse recent (2010-2016) articles concerning m-health application developments and their associated design or development issues. We identify eight application categories, ten design issues (security, privacy, literacy, accessibility, acceptability, reliability, usability, confidentiality, integrity and knowledge sharing) and the stakeholders and development techniques involved. The analysis suggests m-health is an emerging field to which design science is particularly appropriate

    Combinatorial-Based Auction For The Transportation Procurement: An Optimization-Oriented Review

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    This paper conducts a literature review on freight transport service procurements (FTSP) and explores the application of combinatorial auctions (CAs) mechanism and the mathematical modeling approach of the associated problems. It provides an overview of modeling the problems and their solution strategies. The results demonstrate that there has been limited scholarly attention to sustainable issues, risk mitigation and the stochastic nature of parameters. Finally, several promising future directions for FTSP research have been proposed, including FTSP for green orientation in the context of carbon reduction, shipper’s reputation, carrier collaboration for bid generation, etc

    Growth and yield of short duration Aman rice (Oryza sativa) cultivars as influenced by age of seedlings

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    An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh during the period from July to December 2019 to study the effect of cultivar and seedling age on the performance of short duration transplant Aman rice. The experiment comprised four Aman rice cultivars, viz., BRRI dhan49, BRRI dhan56, BRRI dhan66 and BRRI dhan71, and four seedling ages viz. 20, 25, 30 and 35-day old seedlings. The experiment was laid out in a randomized complete block design with three replications. Results of the study showed that growth, yield and yield contributing characters were significantly influenced by cultivars, seedlings age and their interactions. At growth stage, BRRI dhan49 with 20-day old seedlings produced the tallest plant (57.67 cm and 67.33 cm, respectively), the highest number of total tillers hill-1 (15.00 and 13.67, respectively) and total dry matter (8.03 g m-2 and 11.50 g m-2, respectively) at 30 and 50 DAT. At harvest, the highest number of total and effective tillers hill-1 (12.82 and 12.00), longest panicle (24.50 cm), highest number of grains panicle-1 (128.80), heaviest 1000-grain weight (23.17 g), highest grain yield (5.35 t ha-1) and highest harvest index (51.69 %) were obtained from the cultivar BRRI dhan66. While, thirty-day old seedlings produced the highest number of total and effective tillers hill-1 (13.46 and 12.70), longest panicle (24.67 cm), highest number of grains panicle-1 (136.90), highest grain (5.62 t ha-1) and straw yields (5.81 t ha-1) and harvest index (51.67 %). In case of interactions, BRRI dhan66 with 30-day old seedlings produced the highest number of total and effective tillers hill-1 (14.67 and 13.97), longest panicle (26.00 cm), highest number of grains panicle-1 (146.7), highest grain yield (6.31 t ha-1) and highest harvest index (52.72 %). So, result of the present study reveals that BRRI dhan66 with 30-days old seedlings was found to be the best for obtaining maximum grain yield

    Solving the winner determination problem with discounted bids in transportation auctions

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    Continuing advances in modern technologies have transformed the procedure of transportation procurement through auctions in supply chain management (SCM). This study examines the online combinatorial auction (CA), which serves customers placed at the nodes of a transportation network, with particular consideration given to carbon emissions. The CA mechanism allows early shipments of the carriers to improve their load consolidation and reduce their repositioning trips. Sustainability and carbon emissions are considered by prioritizing the carrier’s carbon reduction performances. Two models are examined under the carbon emission regulations (Carbon tax and Cap-and-offset) to choose the winners in the CA. Our aim is to minimize the cost of transportation procurement and reduce carbon emissions by incorporating the green reputation-based winner determination problem within the procurement model. Computational experiments reveal the positive impact of prioritization and discounted offers in reducing both transportation costs and the number of empty trips. Indeed, our results show the introduction of the discounted bids allows a reduction of about 2% in the transportation cost for the shipper and 24% of empty movements, on average, for the carriers

    Designing Social Networking Mobile App for Diabetes Management

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    The knowledge required for diabetes prevention and management among the rural people in developing countries vastly remains in the state of non-existence. To address this, a diabetic knowledge sharing platform, as an effective means for diabetes prevention, control, and treatment, can play role in increasing diabetes awareness and literacy. Currently researchers have emphasized the scope of peer-led learning by knowledge sharing on social media platforms in healthcare context. Therefore, by identifying this scope, we have prototyped a mobile app integrated with social media features to enable diabetic patients for cost-effective peer-led learning, knowledge sharing, and awareness building. In this process, we resorted to follow the cycles and guidelines as proposed in the Information System Research (ISR) framework for identifying users\u27 needs and preferences as well as building the theoretical foundation for the design of an app. This study demonstrates that the users had positive response and well acceptance to this prototype app as a medium for peer-led for diabetes management. Based on the findings, the researchers are optimistic about the potentiality of the app for a wider scale adoption by diabetic patients as a cost-effective peer-led learning platform

    Prácticas y Resultados de la Enseñanza de la Lengua Comunicativa en Escuelas Secundarias Superiores en Zonas Rurales de Bangladesh

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    This paper aims to provide insights into the challenges of Communicative Language Teaching (CLT) practice at higher secondary level in Bangladeshi rural settings. Employing qualitative approach, in-depth interviews were conducted with 24 rural English language teachers to explore the problems they face in CLT implementation. The interview data were scrutinized using thematic analysis. Three major themes emerge from the analysis which are: (i) pedagogical factors; (ii) contextual factors; and (iii) personal factors that obstruct CLT implementation to reach at its expected outcome. The paper reveals the gap between the objectives of the present ELT curriculum and teachers’ practices. The teachers are optimistic with CLT approach for improving students’ English skill, but they need viable support to overcome the factors working as the barriers of its proper implementation. Based on the teachers’ suggestion, the study recommends the aligning of curriculum and test format, and also the training and logistic support for the teachers to overcome the issues surrounding the CLT implementation in the rural context of Bangladesh.Este documento tiene como objetivo proporcionar información sobre los desafíos de la práctica de Enseñanza de la Lengua Comunicativa (ELC) en el nivel secundario superior en los entornos rurales de Bangladesh. Empleando un enfoque cualitativo se realizaron entrevistas en profundidad con 24 profesores de inglés de áreas rurales, para explorar los problemas que enfrentan en la implementación de ELC. Los datos fueron examinados utilizando un análisis temático. Tres temas principales surgieron del análisis: (i) factores pedagógicos; (ii) factores contextuales; y (iii) factores personales que obstruyen la implementación de ELC para alcanzar el resultado esperado. El documento revela la brecha entre los objetivos del presente currículo ELC y las prácticas de los docentes. Los maestros son optimistas con el enfoque ELC para mejorar las habilidades de inglés de los estudiantes, pero necesitan un apoyo viable para superar los factores que actúan como barreras para su correcta implementación. Basado en la sugerencia de los maestros, el estudio recomienda alinear el currículo y el formato de las pruebas, y también la capacitación y el apoyo logístico para que los maestros superen los problemas que rodean la implementación de ELC en el contexto rural de Bangladesh
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