49 research outputs found

    Does operational oceanography address the needs of fisheries and applied environmental scientists?

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    Although many oceanographic data products are now considered operational, continued dialogue between data producers and their user communities is still needed. The fisheries and environmental science communities have often been criticized for their lack of multidisciplinarity, and it is not clear whether recent developments in operational oceanographic products are addressing these needs. The International Council for the Exploration of the Sea (ICES) Working Group on Operational Oceanographic products for Fisheries and Environment (WGOOFE) identified a potential mismatch between user requirements and the perception of requirements by the providers. Through a questionnaire (98 respondents), WGOOFE identified some of these issues. Although products of physical variables were in higher demand, several biological parameters scored in the top 10 rankings. Users placed specific focus on historic time series products with monthly or annual resolution and updating on similar time scales. A significant percentage requested access to numerical data rather than graphical output. While the outcomes of this survey challenge our views of operational oceanography, several initiatives are already attempting to close the gap between user requirements and products available

    On the quantum KP hierarchy and its relation to the non-linear Schr\"odinger equation

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    We establish a relation between the classical non-linear Schr\"odinger equation and the KP hierarchy, and we extend this relation to the quantum case by defining a quantum KP hierarchy. We present evidence that an integrable hierarchy of equations is obtained by quantizing the first Hamiltonian structure of the KdV equation. The connection between infinite-dimensional algebras and integrable models is discussed.Comment: 16 pages, KCL-TH-92-

    Extensions of the matrix Gelfand-Dickey hierarchy from generalized Drinfeld-Sokolov reduction

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    The p×pp\times p matrix version of the rr-KdV hierarchy has been recently treated as the reduced system arising in a Drinfeld-Sokolov type Hamiltonian symmetry reduction applied to a Poisson submanifold in the dual of the Lie algebra gl^prC[λ,λ1]\widehat{gl}_{pr}\otimes {\Complex}[\lambda, \lambda^{-1}]. Here a series of extensions of this matrix Gelfand-Dickey system is derived by means of a generalized Drinfeld-Sokolov reduction defined for the Lie algebra gl^pr+sC[λ,λ1]\widehat{gl}_{pr+s}\otimes {\Complex}[\lambda,\lambda^{-1}] using the natural embedding glprglpr+sgl_{pr}\subset gl_{pr+s} for ss any positive integer. The hierarchies obtained admit a description in terms of a p×pp\times p matrix pseudo-differential operator comprising an rr-KdV type positive part and a non-trivial negative part. This system has been investigated previously in the p=1p=1 case as a constrained KP system. In this paper the previous results are considerably extended and a systematic study is presented on the basis of the Drinfeld-Sokolov approach that has the advantage that it leads to local Poisson brackets and makes clear the conformal (W\cal W-algebra) structures related to the KdV type hierarchies. Discrete reductions and modified versions of the extended rr-KdV hierarchies are also discussed.Comment: 60 pages, plain TE

    Technology-Supported Storytelling (TSST) Strategy in Virtual World for Multicultural Education

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    Learning culture through stories is an effective way for multicultural education, since stories are one of the most powerful and personal ways that we learn about the world. Storytelling, the process of telling stories, is a form of communication and a universal expression of culture. With the development of technology, storytelling emerges out of diverse ways. This study explores the storytelling in virtual worlds for multicultural education, and devises a Technology-Supported storytelling (TSST) strategy by examining and considering the characteristics of virtual worlds which could be incorporated into the storytelling, and then uses this strategy to teach Korean culture to students with different culture background. With this innovative TSST strategy in virtual world, this study expects to provide a guide to practice for teaching multicultural in digital era

    Nitric Oxide and Other Molecules: Molecular Modeling and Low-frequency Exploration Using the Murchison Widefield Array

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    We present new molecular modeling for 14NO and 15NO and a deep, blind molecular line survey at low radio frequencies (99-129 MHz). This survey is the third in a series completed with the Murchison Widefield Array (MWA), but in comparison with the previous surveys, uses 4 times more data (17 hr versus 4 hr) and is 3 times better in angular resolution (1′ versus 3′). The new molecular modeling for nitric oxide and its main isotopologue has seven transitions within the MWA frequency band (although we also present the higher-frequency transitions). Although we did not detect any new molecular lines at a limit of 0.21 Jy beam-1, this work is an important step in understanding the data processing challenges for the future Square Kilometre Array and places solid limits on what is expected in the future of low-frequency surveys. The modeling can be utilized for future searches of nitric oxide

    Temporal causality and the dynamics of crime in Turkey

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    This study is concerned with understanding of the factors of aggregate, nonviolent and violent crime categories in Turkey for the period 1965-2009. The determinants of all crime categories are related to selected socio-economic factors. Bounds testing approach to cointegration is employed to test the existence of long-run relationship amongst the variables. Cointegration analysis yields the major contributors of crime are income and unemployment. The direction of causalities between the variables are established using within and out of sample causality tests. The findings from this study present the dynamics of aggregate, violent and non-violent crimes to design and implement any relevant policy measures to combat them

    Steering liquid metal flow in microchannels using low voltages

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    Liquid metals based on gallium, such as eutectic gallium indium (EGaIn) and Galinstan, have been integrated as static components in microfluidic systems for a wide range of applications including soft electrodes, pumps, and stretchable electronics. However, there is also a possibility to continuously pump liquid metal into microchannels to create shape reconfigurable metallic structures. Enabling this concept necessitates a simple method to control dynamically the path the metal takes through branched microchannels with multiple outlets. This paper demonstrates a novel method for controlling the directional flow of EGaIn liquid metal in complex microfluidic networks by simply applying a low voltage to the metal. According to the polarity of the voltage applied between the inlet and an outlet, two distinct mechanisms can occur. The voltage can lower the interfacial tension of the metal via electrocapillarity to facilitate the flow of the metal towards outlets containing counter electrodes. Alternatively, the voltage can drive surface oxidation of the metal to form a mechanical impediment that redirects the movement of the metal towards alternative pathways. Thus, the method can be employed like a 'valve' to direct the pathway chosen by the metal without mechanical moving parts. The paper elucidates the operating mechanisms of this valving system and demonstrates proof-of-concept control over the flow of liquid metal towards single or multiple directions simultaneously. This method provides a simple route to direct the flow of liquid metal for applications in microfluidics, optics, electronics, and microelectromechanical systems.</p

    Dynamically adaptive educational games: A new perspective

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    Sajjadi P, Van Broeckhoven F, De Troyer O. Dynamically adaptive educational games: A new perspective. In: International Conference on Serious Games. 2014: 71--76

    Interaction design and usability of learning spaces in 3D multi-user virtual worlds

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    Three-dimensional virtual worlds are multimedia, simulated environments, often managed over the Web, which users can 'inhabit' and interact via their own graphical self-representations known as 'avatars'. 3D virtual worlds are being used in many applications: education/training, gaming, social networking, marketing and commerce. Second Life is the most widely used 3D virtual world in education. However, problems associated with usability, navigation and wayfinding in 3D virtual worlds may impact on student learning and engagement. Based on empirical investigations of learning spaces in Second Life, this paper presents design guidelines to improve the usability and ease of navigation in 3D spaces. Methods of data collection include semi-structured interviews with Second Life students, educators and designers. The findings have revealed that design principles from the fields of urban planning, Human-Computer Interaction, Web usability, geography and psychology can influence the design of spaces in 3D multi-user virtual environments
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