7,111 research outputs found

    Scalable Multi-cloud Platform to Support Industry and Scientific Applications

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    Cloud computing offers resources on-demand and without large capital investments. As such, it is attractive to many industry and scientific application areas that require large computation and storage facilities. Although Infrastructure as a Service (IaaS) clouds provide elasticity and on demand resource access, the challenges represented by multi-cloud capabilities and application level scalability are still largely unsolved. The CloudSME Simulation Platform (CSSP) extended with the Microservices-based Cloud Application-level Dynamic Orchestrator (MiCADO) addresses such issues. CSSP is a generic multi-cloud access platform for the development and execution of large scale industry and scientific simulations on heterogeneous cloud resources. MiCADO provides application level scalability to optimise execution time and costs. This paper outlines how these technologies have been developed in various European research projects, and showcases several application case-studies from manufacturing, engineering and life-sciences where these tools have been successfully utilised to execute large-scale simulations in an optimised way on heterogeneous cloud infrastructures

    Design and development of a flexible business simulation game.

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    Availability of managers competent in managing organisations operating in a competitive and global market is among the key factors affecting the likelihood of the success of the transition economies. This in turn will depend on the ability of the higher education institutions to align their curriculum with the needs of industry and commerce. Changes in the curriculum need to be underpinned with the appropriate learning material. This research project, in a small way, fulfils this important need. The primary aim of the work presented in this dissertation is to develop an interactive learning tool that enables the management student to acquire relevant managerial competencies, and knowledge regarding functions and processes of a firm operating in a competitive economy. Development of a business game demands a framework that specifies its requirements. This framework was established by examining the relevant literature, existing business games, and the specific needs of the transition economies. These requirements were used to identify the detailed objectives of the research. The research methodology consisted of: (a) analysis of relevant published papers and existing business games; (b) modelling of business processes; (c) testing the internal validity of the business game using multivariate statistical tools; and (d) testing the external validity of the business game using structured observations, report feedback, and survey of participants. In line with the objectives of this research, a multifunctional Business Simulation Game (BSG) was developed. The game enables the student to acquire skills and knowledge of functional areas, as well as, to develop an understanding of the relationship of those functional areas in the organisation. The resultant BSG has a number of unique features. First, it can operate in two languages, English and Hungarian. Moreover, the program can be easily modified to accommodate other languages. This is important because a majority of students in transition countries can not speak English. Second, based 'on the "white box theory", the students have access to detailed analysis of each functional area. Third, BSG allows the students to choose between practice (playing against the computer) and competitive (playing against other students) mode. Fourth, the development of the functional areas used in the BSG contains new concepts and methods. A new dynamic aggregate market model was developed and validated by using real life data. A new approach for modelling short run production and cost function allows for a deeper understanding of economic theory. The accounting function of BSG includes a completely new methodology for the harmonisation of different accounting systems, and a new approach to computerised accounting. BSG was validated internally and externally. The internal validation included face validation; sensitivity tests; consideration of the existence of dominant factors; and examination of the stability of decision variable – performance criterion relationships. These were accomplished using the response surface methodology and multivariate regression analysis. The external validation was concerned with the effectiveness of BSG as a learning tool. The data was collected by structured observation, report feedback, and survey data from three different cohorts of graduate and postgraduate students. This data was analysed using factor analysis; discriminant analysis; cross tabulation; and independent sample t-test. The analysis of the qualitative and quantitative data suggests that students found BSG to be an effective learning tool. The conduct of this study has found room for further research and improvement to BSG. These include methodological design; content; and the platform of the program. Methodologically, incorporating a linear programming method can improve the final evaluation of the market influential factors of companies, and help to optimise the product distribution. A comprehensive model with short-run revenue and profit functions allows for building up a more comprehensive model. Sustainable development will be included in the future that will be developed on Windows platform. The output of this research project is an interactive learning vehicle that can help the Hungarian business students at all levels to acquire the managerial competencies required to manage in a competitive economy. BSG can also be used by students in other transition economies, as well as students in first and third world countries

    Theory of elementary excitations in unstable Bose-Einstein condensates

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    Like classical fluids, quantum gases may suffer from hydrodynamic instabilities. Our paper develops a quantum version of the classical stability analysis in fluids, the Bogoliubov theory of elementary excitations in unstable Bose-Einstein condensates. In unstable condensates the excitation modes have complex frequencies. We derive the normalization conditions for unstable modes such that they can serve in a mode decomposition of the noncondensed component. Furthermore, we develop approximative techniques to determine the spectrum and the mode functions. Finally, we apply our theory to sonic horizons - sonic black and white holes. For sonic white holes the spectrum of unstable modes turns out to be intrinsically discrete, whereas black holes may be stable

    Quantum back-action of optical observations on Bose condensates

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    Impressive pictures of moving Bose-Einstein condensates have been taken using phase-contrast imaging M. R. Andrews et al., Science 273, 84 (1996). We calculate the quantum backaction of this measurement technique. We find that phase-contrast imaging is not a quantum nondemolition measurement of the atomic density. Instead, the condensate gets gradually depleted at a rate that is proportional to the light intensity and to the inverse cube of the optical wave length. The fewer atoms are condensed the higher is the required intensity to see a picture, and, consequently, the higher is the induced backaction. To describe the quantum physics of phase-contrast imaging we put forward a new approach to quantum-optical propagation. We develop an effective field theory of paraxial optics in a fully quantized atomic medium.Comment: 11 pages RevTex, 2 ps figures, revised. European Physical Journal D (in press

    Reply to the ``Comment on `quantum backaction of optical observations on Bose-Einstein condensates' ''

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    In our paper we estimated the quantum backaction of dispersive imaging with off-resonant light on Bose-Einstein condensates. We have calculated the rates of the two processes involved, phase diffusion and depletion of the condensate. We compare here the depletion rate obtained within our model limitations to the Rayleigh scattering rate, both having the same physical origin: dispersive interaction of light with matter. We show that residual absorption sets indeed the limit of dispersive imaging.Comment: 1 page (Reply to comment

    Selecting molecules in the vibrational and rotational ground state by deflection

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    A beam of diatomic molecules scattered off a standing wave laser mode splits according to the rovibrational quantum state of the molecules. Our numerical calculation shows that single state resolution can be achieved by properly tuned, monochromatic light. The proposed scheme allows for selecting non-vibrating and non-rotating molecules from a thermal beam, implementing a laser Maxwell's demon to prepare a rovibrationally cold molecular ensemble.Comment: 11 pages, LaTeX. To appear in the European Physical Journal

    Making distributed computing infrastructures interoperable and accessible for e-scientists at the level of computational workflows

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    As distributed computing infrastructures evolve, and as their take up by user communities is growing, the importance of making different types of infrastructures based on a heterogeneous set of middleware interoperable is becoming crucial. This PhD submission, based on twenty scientific publications, presents a unique solution to the challenge of the seamless interoperation of distributed computing infrastructures at the level of workflows. The submission investigates workflow level interoperation inside a particular workflow system (intra-workflow interoperation), and also between different workflow solutions (inter-workflow interoperation). In both cases the interoperation of workflow component execution and the feeding of data into these components workflow components are considered. The invented and developed framework enables the execution of legacy applications and grid jobs and services on multiple grid systems, the feeding of data from heterogeneous file and data storage solutions to these workflow components, and the embedding of non-native workflows to a hosting meta-workflow. Moreover, the solution provides a high level user interface that enables e-scientist end-users to conveniently access the interoperable grid solutions without requiring them to study or understand the technical details of the underlying infrastructure. The candidate has also developed an application porting methodology that enables the systematic porting of applications to interoperable and interconnected grid infrastructures, and facilitates the exploitation of the above technical framework

    The formation of carbonaceous layer from ethylene over various transition metal catalysts – an FT-IR study

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    The ethylene-derived carbonaceous overlayers were studied over silica-supported Pt, Pd, Rh and Cu catalysts by FT-IR spectroscopy under desorption conditions. As a general feature it was observed over all catalysts that upon increasing the desorption temperature the overlayer gradually became poor in hydrogen. The structure of the overlayers was similar over the silica-supported Pt, Pd and Rh. On increasing the reaction temperature the σ-adsorbed half-hydrogenated species are transformed to adsorbed ethylidyne. On the Cu catalyst prepared with ion exchange a similar picture emerged, while on those prepared with precipitation ethylidyne soon became the predominant species. Hydrogen swept off the carbonaceous species from the transition metals, however, copper retained large portions of it
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