1,392,292 research outputs found

    Geografski informacijski sistemi v Sloveniji 2009–2010

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    This is the tenth volume (‘Geographic information systems in Slovenia, 2009–2010’) in a row, featuring thirty-four research and survey papers on the current use of geographic information systems (GIS) in Slovenia. GIS offer an excellent opportunity for interdisciplinary cooperation. This allows knowledge from a specific discipline to be expanded with findings from related disciplines, which enables further development of individual disciplines and synergy effects in finding solutions to emerging problems.Monografija, deseta po vrsti, v 34 znanstvenih in strokovnih prispevkih predstavlja presek trenutnega stanja uporabe geografskih informacijskih sistemov (GIS) v Sloveniji. GIS-i nudijo odlično priloĆŸnost za interdisciplinarno sodelovanje. Tako se znanje posamezne vede bogati z dognanji sorodnih ved, kar omogoča nadaljnji razvoj posameznih strok ter sinergijske učinke v iskanju reĆĄitev za porajajoče se probleme. V desetih knjigah Geografski informacijski sistemi v Sloveniji je bilo skupaj objavljenih 294 prispevkov na skoraj tritisoč straneh

    The dynamics over the next few years of the Spanish mobile telecommunications market share: a mathematical modelling approach

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    This is an author's accepted manuscript of an article published in: “Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences"; Volume 20, Issue 6, 2014; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1080/13873954.2013.843572Taking into account available data from 2002 to 2009 about the market share percentages of the Spanish mobile telecommunications service providers, a dynamic diffusion model to study the evolution of the clients’ change between the different companies during the period 2010–2016 is proposed. The constructed model provides a tool for forecasting short-term trends about the customers’ preferences with respect to mobile network operators taking into account both, autonomous decisions due to direct marketing and advertising strategies, and also decisions adopted through interaction via social influence. The model can provide insights to companies for designing strategies in order to gain market share.This work has been partially supported by the FIS PI-10/01433; the Spanish Government and European Regional Development Fund (FEDER) [grant number MTM2009-08587]; and the Universitat Politecnica de Valencia [grant number PAID06-11-2070].CervellĂł Royo, RE.; CortĂ©s, J.; Santonja, F.; Villanueva MicĂł, RJ. (2014). The dynamics over the next few years of the Spanish mobile telecommunications market share: a mathematical modelling approach. Mathematical and Computer Modelling of Dynamical Systems. 20(6):557-565. https://doi.org/10.1080/13873954.2013.843572S557565206Gruber, H. (1999). An investment view of mobile telecommunications in the European Union. Telecommunications Policy, 23(7-8), 521-538. doi:10.1016/s0308-5961(99)00042-7CortĂ©s, J.-C., Lombana, I.-C., & Villanueva, R.-J. (2010). Age-structured mathematical modeling approach to short-term diffusion of electronic commerce in Spain. Mathematical and Computer Modelling, 52(7-8), 1045-1051. doi:10.1016/j.mcm.2010.02.030Gruber, H. (2001). Competition and innovation. Information Economics and Policy, 13(1), 19-34. doi:10.1016/s0167-6245(00)00028-7Gruber, H., & Verboven, F. (2001). The diffusion of mobile telecommunications services in the European Union. European Economic Review, 45(3), 577-588. doi:10.1016/s0014-2921(00)00068-4Bettencourt, L. (1997). Customer voluntary performance: Customers as partners in service delivery. Journal of Retailing, 73(3), 383-406. doi:10.1016/s0022-4359(97)90024-5Herrera-GonzĂĄlez, F., & CastejĂłn-MartĂ­n, L. (2009). The endless need for regulation in telecommunication: An explanation. Telecommunications Policy, 33(10-11), 664-675. doi:10.1016/j.telpol.2009.07.001Santonja, F.-J., Morales, A., Villanueva, R.-J., & CortĂ©s, J.-C. (2012). Analysing the effect of public health campaigns on reducing excess weight: A modelling approach for the Spanish Autonomous Region of the Community of Valencia. Evaluation and Program Planning, 35(1), 34-39. doi:10.1016/j.evalprogplan.2011.06.00

    A Spectral-Scanning Nuclear Magnetic Resonance Imaging (MRI) Transceiver

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    An integrated spectral-scanning nuclear magnetic resonance imaging (MRI) transceiver is implemented in a 0.12 mum SiGe BiCMOS process. The MRI transmitter and receiver circuitry is designed specifically for small-scale surface MRI diagnostics applications where creating low (below 1 T) and inhomogeneous magnetic field is more practical. The operation frequency for magnetic resonance detection and analysis is tunable from 1 kHz to 37 MHz, corresponding to 0-0.9 T magnetization for ^1H (hydrogen). The concurrent measurement bandwidth is approximately one frequency octave. The chip can also be used for conventional narrowband nuclear magnetic resonance (NMR) spectroscopy from 1 kHz up to 250 MHz. This integrated transceiver consists of both the magnetic resonance transmitter which generates the required excitation pulses for the magnetic dipole excitation, and the receiver which recovers the responses of the dipoles

    Absolute electrical impedance tomography (aEIT) guided ventilation therapy in critical care patients: simulations and future trends

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    Thoracic electrical impedance tomography (EIT) is a noninvasive, radiation-free monitoring technique whose aim is to reconstruct a cross-sectional image of the internal spatial distribution of conductivity from electrical measurements made by injecting small alternating currents via an electrode array placed on the surface of the thorax. The purpose of this paper is to discuss the fundamentals of EIT and demonstrate the principles of mechanical ventilation, lung recruitment, and EIT imaging on a comprehensive physiological model, which combines a model of respiratory mechanics, a model of the human lung absolute resistivity as a function of air content, and a 2-D finite-element mesh of the thorax to simulate EIT image reconstruction during mechanical ventilation. The overall model gives a good understanding of respiratory physiology and EIT monitoring techniques in mechanically ventilated patients. The model proposed here was able to reproduce consistent images of ventilation distribution in simulated acutely injured and collapsed lung conditions. A new advisory system architecture integrating a previously developed data-driven physiological model for continuous and noninvasive predictions of blood gas parameters with the regional lung function data/information generated from absolute EIT (aEIT) is proposed for monitoring and ventilator therapy management of critical care patients

    IMPROVING THE DEPENDABILITY OF DESTINATION RECOMMENDATIONS USING INFORMATION ON SOCIAL ASPECTS

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    Prior knowledge of the social aspects of prospective destinations can be very influential in making travel destination decisions, especially in instances where social concerns do exist about specific destinations. In this paper, we describe the implementation of an ontology-enabled Hybrid Destination Recommender System (HDRS) that leverages an ontological description of five specific social attributes of major Nigerian cities, and hybrid architecture of content-based and case-based filtering techniques to generate personalised top-n destination recommendations. An empirical usability test was conducted on the system, which revealed that the dependability of recommendations from Destination Recommender Systems (DRS) could be improved if the semantic representation of social attributes information of destinations is made a factor in the destination recommendation process

    Model estimation of cerebral hemodynamics between blood flow and volume changes: a data-based modeling approach

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    It is well known that there is a dynamic relationship between cerebral blood flow (CBF) and cerebral blood volume (CBV). With increasing applications of functional MRI, where the blood oxygen-level-dependent signals are recorded, the understanding and accurate modeling of the hemodynamic relationship between CBF and CBV becomes increasingly important. This study presents an empirical and data-based modeling framework for model identification from CBF and CBV experimental data. It is shown that the relationship between the changes in CBF and CBV can be described using a parsimonious autoregressive with exogenous input model structure. It is observed that neither the ordinary least-squares (LS) method nor the classical total least-squares (TLS) method can produce accurate estimates from the original noisy CBF and CBV data. A regularized total least-squares (RTLS) method is thus introduced and extended to solve such an error-in-the-variables problem. Quantitative results show that the RTLS method works very well on the noisy CBF and CBV data. Finally, a combination of RTLS with a filtering method can lead to a parsimonious but very effective model that can characterize the relationship between the changes in CBF and CBV
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