281,802 research outputs found

    Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bonnel, J., Thode, A., Wright, D., & Chapman, R. Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone. The Journal of the Acoustical Society of America, 147(3), (2020): 1897, doi:10.1121/10.0000937.Classical ocean acoustic experiments involve the use of synchronized arrays of sensors. However, the need to cover large areas and/or the use of small robotic platforms has evoked interest in single-hydrophone processing methods for localizing a source or characterizing the propagation environment. One such processing method is “warping,” a non-linear, physics-based signal processing tool dedicated to decomposing multipath features of low-frequency transient signals (frequency f  1 km). Since its introduction to the underwater acoustics community in 2010, warping has been adopted in the ocean acoustics literature, mostly as a pre-processing method for single receiver geoacoustic inversion. Warping also has potential applications in other specialties, including bioacoustics; however, the technique can be daunting to many potential users unfamiliar with its intricacies. Consequently, this tutorial article covers basic warping theory, presents simulation examples, and provides practical experimental strategies. Accompanying supplementary material provides matlab code and simulated and experimental datasets for easy implementation of warping on both impulsive and frequency-modulated signals from both biotic and man-made sources. This combined material should provide interested readers with user-friendly resources for implementing warping methods into their own research.This work was supported by the Office of Naval Research (Task Force Ocean, project N00014-19-1-2627) and by the North Pacific Research Board (project 1810). Original warping developments were supported by the French Delegation Generale de l'Armement

    The use of learning management platforms in school context - a national study

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    This report results from a national study carried out under the Project “Educational application of learning management platforms”, supported and funded by the Computers, Networks, and Internet in Schools department of the Portuguese Ministry of Education- General Directorate for Innovation and Educational Development. This report has been developed by the ICT Competence Centre of the Faculty of Sciences- University of Lisbon, during the school year 2007/2008

    School use of learning platforms and associated technologies

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    Study of benefits and effective use of learning platforms in schools based on 12 case studie

    Institutional Repositories: Features, Architecture, Design and Implementation Technologies

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    Europe is the leading continent in terms of active adoption and use of Digital Libraries – particularly Institutional Repositories (IRs). Africa has not done poorly in this area with a steady increase from 19 repositories in 2008 to 46 in January, 2011 but there is need to raise awareness and channel efforts towards making IRs easily accessible to Africans through ubiquitous channels such as hand-helds and mobile devices. This paper reviews the features, architecture, design and implementation technologies of IRs. In addition, it highlights viable research areas that can be pursued by African researchers in the field of Digital Libraries. It also encourages research efforts to focus on areas that will be beneficial to Africa

    The Testbed for LISA Analysis Project

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    The Testbed for LISA Analysis (TLA) Project aims to facilitate the development, validation and comparison of different methods for LISA science data analysis, by the broad LISA Science Community, to meet the special challenges that LISA poses. It includes a well-defined Simulated LISA Data Product (SLDP), which provides a clean interface between the communities that have developed to model and to analyze the LISA science data stream; a web-based clearinghouse (at ) providing SLDP software libraries, relevant software, papers and other documentation, and a repository for SLDP data sets; a set of mailing lists for communication between and among LISA simulators and LISA science analysts; a problem tracking system for SLDP support; and a program of workshops to allow the burgeoning LISA science community to further refine the SLDP definition, define specific LISA science analysis challenges, and report their results. This note describes the TLA Project, the resources it provides immediately, its future plans, and invites the participation of the broader community in the furtherance of its goals.Comment: 5 pages, no figure

    Mobile application platform heterogeneity: Android vs Windows phone vs iOS vs Firefox OS

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    Modern smartphones have a rich spectrum of increasingly sophisticated features, opening opportunities for software-led innovation. Of the large number of platforms to develop new software on, in this paper we look closely at three platforms identified as market leaders for the smartphone market by Gartner Group in 2013 and one platform, Firefox OS, representing a new paradigm for operating systems based on web technologies. We compare the platforms in several different categories, such as software architecture, application development, platform capabilities and constraints, and, finally, developer support. Using the implementation of a mobile version of the tic-tac-toe game on all the four platforms, we seek to investigate strengths, weaknesses and challenges of mobile application development on these platforms. Big differences are highlighted when inspecting community environments, hardware abilities and platform maturity. These inevitably impact upon developer choices when deciding on mobile platform development strategies

    Educational change and ICT: an exploration of priorities 2 and 3 of the DfES e-strategy in schools and colleges: the current landscape and implementation issues

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    Landscape review of integrated online support for learners and collaborative approaches to personalised learning activities
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