1,293 research outputs found

    TriG - A GNSS Precise Orbit and Radio Occultation Space Receiver

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    The GPS radio occultation (RO) technique [1] produces measurements in the ionosphere and neutral atmosphere [2] that contribute to monitoring space weather and climate change; and improving operational weather prediction. The high accuracy of RO soundings, traceable to SI standards, makes them ideal climate benchmark observations. For weather applications, RO observations improve the accuracy of weather forecasts by providing temperature and moisture profiles of sub-km vertical resolution, over land and ocean and in the presence of clouds. JPL is currently flying a handful of RO instruments [3] on various satellites in Low Earth Orbit (LEO). Although these receivers have served to pioneer occultation measurements, various advances in technology and understanding of the RO technique along with availability of new signals from GPS and other GNSS satellites allow us to design an improved next generation space-based Precise Orbit Determination (POD) and RO receiver, the TriG receiver. The paper describes the architecture and implementation of the JPL TriG receiver as well as results obtained with a prototype receiver demonstrating key technologies necessary for a next-generation space science receiver

    Model-Based Systems Engineering Applied to the Detection and Correction of Object Slippage Within a Dexterous Robotic Hand from the Laboratory to Simulation

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    Now more than ever, it is important to have the ability to replicate robotic tasks in simulation and be able to validate the simulation against stakeholder requirements and verify the simulation against simulation requirements. In a previous study, a five-fingered robotic hand, the Shadow Dexterous Hand, with haptic BioTac SP sensors attached was used to detect the moment of slip of an object from the robotic hand while weight was continuously being added and stop the object from falling from the grasp while not overcorrecting. This work was accomplished by Dr. Zhenyu Lin, Dr. John S. Baras, and the author in the Autonomy Robotics Cognition Laboratory at the University of Maryland. This thesis will present the use of Model-Based System Engineering techniques to replicate the detection and correction of object slippage by a five-fingered robotic hand using force feedback control in simulation

    A matter of security, privacy and trust: A study of the principles and values of encryption in New Zealand

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    Cybersecurity is crucial for ensuring the safety and well-being of the general public, businesses, government, and the country as a whole. New Zealand has a reasonably comprehensive and well-grounded legal regime and strategy for dealing with cybersecurity matters. However, there is one area that deserves further attention and discussion ā€“ encryption. Encryption is at the heart of and underpins many of the technologies and technical processes used for computer and network security, but current laws and policies do not expressly cover this significant technology. The principal objective of this study is to identify the principles and values of encryption in New Zealand with a view to informing future developments of encryptionrelated laws and policies. The overarching question is: What are the fundamental principles and values that apply to encryption? In order to answer this question, the study adopts an interdisciplinary approach that examines the technical, legal and social dimensions of encryption. With regard to the technical dimensions, this requires exploring the technical elements and aspects of encryption and how they can impact law and society. In relation to law, existing and proposed encryption law and policies in New Zealand and other jurisdictions are examined in terms of how they affect and are affected by encryption. On the social dimension, the perceptions, opinions and beliefs of three groups of stakeholders most concerned about encryption (i.e., the general public, businesses and government) are recognised and considered

    Time to get real: the case for critical action research in purchasing and supply management

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    In fragile and often complex supply chains, PSM failures continue to be reported in the media, often with severe economic, social and environmental consequences. To encourage organisations to engage in responsible PSM, we need engaged research. In this paper we argue that Action Research (AR) is an influential, participative method to challenge the more dominant versions of PSM impacts, which tend to focus only on the positive, and often only monetised elements of what is valued. AR places change at the core of the research process, requiring critical reflexive practice of the impact of assumptions, values and actions on others. We argue that PSM research has more potential for influence if it starts from a ā€˜realā€™ problem anchored in practice, and that crucially, the problem itself should be challenged dialogically by scholars, practitioners and diverse stakeholders. Critical AR can reframe performance from a technical, company-centric notion to explore broader relationships between inputs and outputs over a longer time frame. We explore the risks and rewards of Critical AR for PSM scholars and draw conclusions on our role as engaged advocates of change
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