8 research outputs found

    Teaching English as a Second Language in an Urban Public University in Sri Lanka : A Reflective Paper

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    The purpose of this Master of Arts (MA) thesis is threefold: First, this reflective paper provides a critical literature review on English Language Teaching (ELT) in Sri Lanka. Second, this reflective paper presents seven guiding principles which will steer my English as a Second Language (ESL) teaching in an urban public university in Sri Lanka. Third, drawing from the seven guiding principles, this reflective paper presents a complete syllabus and three assignments as concrete examples (attached as appendixes) which will be implemented in a College of Humanities and Social Sciences in an urban public university in Sri Lanka. The importance of the present reflective paper can be summarized under four main points: First, the critical literature review could help researchers and practitioners to better understand the complex linguistic situation and ELT in Sri Lanka. Second, based on the seven guiding principles I will have a new syllabus which will be implemented in my ESL classes in an urban public university in Sri Lanka. After the implementation of the syllabus, I will reflect on my experience of implementing the syllabus and improve the syllabus further. Third, the seven guiding principles which will inform my future practice as an ESL teacher are transferable to English dominated post-colonial countries such as India, Pakistan, Bangladesh and so on. As a novice ESL teacher in an urban public university in Sri Lanka, one of the challenges I faced was the lack of a formal syllabus for my ESL classes. It gave rise to multiple issues in relation to teaching methodology, lesson planning, and teaching materials, resulting in the dissatisfaction of my students and myself. It was the lack of a formal syllabus for my ESL classes that motivated me to design a syllabus for an intermediate level ESL course in an urban public university in Sri Lanka. I believe that the new syllabus steered by the seven guiding principles presented in this MA thesis will create a new synergy in my future ESL classrooms

    MEMS Accelerometers

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    Micro-electro-mechanical system (MEMS) devices are widely used for inertia, pressure, and ultrasound sensing applications. Research on integrated MEMS technology has undergone extensive development driven by the requirements of a compact footprint, low cost, and increased functionality. Accelerometers are among the most widely used sensors implemented in MEMS technology. MEMS accelerometers are showing a growing presence in almost all industries ranging from automotive to medical. A traditional MEMS accelerometer employs a proof mass suspended to springs, which displaces in response to an external acceleration. A single proof mass can be used for one- or multi-axis sensing. A variety of transduction mechanisms have been used to detect the displacement. They include capacitive, piezoelectric, thermal, tunneling, and optical mechanisms. Capacitive accelerometers are widely used due to their DC measurement interface, thermal stability, reliability, and low cost. However, they are sensitive to electromagnetic field interferences and have poor performance for high-end applications (e.g., precise attitude control for the satellite). Over the past three decades, steady progress has been made in the area of optical accelerometers for high-performance and high-sensitivity applications but several challenges are still to be tackled by researchers and engineers to fully realize opto-mechanical accelerometers, such as chip-scale integration, scaling, low bandwidth, etc

    MEMS Inertial Sensor to Measure the Gravity Gradient Torque in Orbit

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    Since the dawn of the Space Age, over six thousand satellites have been launched into Earth orbit. The function of determining the orientation of a satellite in orbit, so that it can point its antennas and instruments in the required direction is known as attitude determination. Depending on the nature of the mission, this important function is typically performed by means of optical instruments that determine the orientation of the satellite with respect to known bodies such as the Earth, the sun, and bright stars. Conventional Earth sensors use cameras and telescopes to locate the position of the Earth's horizon and hence to calculate the orientation of the satellite. In the event that a satellite starts to tumble, existing Earth sensors that use optical sensing are severely limited in their ability to reacquire the attitude due to the limited field of view of the instruments. Also, due to this limited field of view, multiple Earth sensor units need to be placed on all faces of the satellite to ensure 4π steradian coverage. Because of the optical sensing principle of existing Earth sensors, constraints are imposed on the positioning of solar panels and antennas so that they do not block the field of view of optical sensors. This thesis describes a novel inertial sensor that uses the Earth's gravity gradient as a reference for attitude determination on-board a satellite in low Earth orbit. Using the gravity gradient for attitude determination makes it possible to realise a single, compact Earth sensor instrument which can be positioned flexibly within the satellite. Due to its 4π steradian field of view, such an instrument can offer added capability as a backup sensor, or act as the main Earth sensor. By using Micro-Electro-Mechanical System (MEMS) technology for the inertial sensor, a target mass of 1 kg and target volume of 1 dm3 can be realised for the entire gravity gradient Earth sensor system. The gravitational force decreases as the square of the distance from the center of the Earth. An elongated object in orbit around the Earth will have slightly different values of gravity acting over the different points in its volume. This gives rise to a small torque, the Gravity Gradient Torque (GGT), on the object. A compact micromachined inertial sensor was designed with an elongated proof mass and compliant spring to measure the GGT, so that the orientation of the proof mass with respect to the normal from the Earth's surface can be determined. Such a sensor on-board a satellite can act as an Earth sensor, and provide information about the satellite attitude with respect to the normal to the Earth's surface. An inertial sensor to measure GGT, which with readout electronics fits within a 1 dm3 volume, has to measure a torque of magnitude 10-15 N.m. Currently, no inertial sensor is capable of such a fine measurement. In addition to the required performance in microgravity, the inertial sensor must be robust enough to be tested on Earth with no special handling, and must survive the vibration and shock of a launch, to be used in space. The readout scheme to measure the displacement due to GGT must also be simple and robust. The designs of two generations of a novel inertial sensor to measure the GGT are presented in the thesis. To be able to measure the GGT with the required accuracy a sensor is designed that has a proof mass 5 cm long, suspended by springs which have widths less than ten microns. The sensor resonant frequency of the inertial sensor is on the order of 1 Hz. A new fabrication process is developed for the sensor, which incorporates hard stops to limit the motion of the proof mass along all the axes, thus making it robust enough for testing without any special precautions. The sensor survives low magnitude vibration tests. A digital electronic readout based on capacitive sensing of the displacement due to GGT, is developed based on commercially available ICs, and allows easy interfacing of the inertial sensor output to a PC or microcontroller. To test the sensor on Earth, a dedicated test setup is developed to replicate the nm-scale motion of the proof mass expected in orbit. The electronic readout is capable of measuring the sub-nm displacements due to GGT. The 2nd generation sensor design with capacitive displacement sensing is the first demonstration of an inertial sensor capable of measuring the GGT in low Earth orbit, and an important step towards realization of a 1 kg, 1 dm3 Earth sensor that uses the gravity gradient of the Earth for attitude determination

    Advances in Intelligent Vehicle Control

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    This book is a printed edition of the Special Issue Advances in Intelligent Vehicle Control that was published in the journal Sensors. It presents a collection of eleven papers that covers a range of topics, such as the development of intelligent control algorithms for active safety systems, smart sensors, and intelligent and efficient driving. The contributions presented in these papers can serve as useful tools for researchers who are interested in new vehicle technology and in the improvement of vehicle control systems

    State of the Art: Small Spacecraft Technology

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    This report provides an overview of the current state-of-the-art of small spacecraft technology, with particular emphasis placed on the state-of-the-art of CubeSat-related technology. It was first commissioned by NASAs Small Spacecraft Technology Program (SSTP) in mid-2013 in response to the rapid growth in interest in using small spacecraft for many types of missions in Earth orbit and beyond, and was revised in mid-2015 and 2018. This work was funded by the Space Technology Mission Directorate (STMD). For the sake of this assessment, small spacecraft are defined to be spacecraft with a mass less than 180 kg. This report provides a summary of the state-of-the-art for each of the following small spacecraft technology domains: Complete Spacecraft, Power, Propulsion, Guidance Navigation and Control, Structures, Materials and Mechanisms, Thermal Control, Command and Data Handling, Communications, Integration, Launch and Deployment, Ground Data Systems and Operations, and Passive Deorbit Devices

    Second Conference on Artificial Intelligence for Space Applications

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    The proceedings of the conference are presented. This second conference on Artificial Intelligence for Space Applications brings together a diversity of scientific and engineering work and is intended to provide an opportunity for those who employ AI methods in space applications to identify common goals and to discuss issues of general interest in the AI community

    Figures of Merit Remembrances of Those Who Built an Army-NASA Collaboration and a New Age of Rotary-Wing Technology 1965-1985

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    The authors of this book are the Figures of Meritthe scientists, engineers, technicians, secretaries, test pilots, managers, visionaries, and leaders who built a unique interagency collaboration under the Army-NASA Joint Agreement at Ames Research Center and ushered in a new age of rotary-wing technology. The U.S. Army Aeronautical Research Laboratory (AARL) was formed in 1965 to strengthen the Armys capabilities in aviation R&D, and the Army-NASA collaboration at Ames was intended to benefit both agencies by sharing personnel and facilities for research in areas of common interest in low-speed aviation
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