761 research outputs found

    Environmental Sustainability and the Hospitality Customer Experience: A Study in Tourist Accommodation

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    Academic research on sustainability in the hospitality industry is scarce and fragmented, and requires a general structure to lend coherence to its approach. There is a need for empirical research to fathom the question of environmental sustainability and customer experience in the hospitality industry and to study the interaction between the two concepts. This paper aims to close these gaps by establishing the nature of the relationship between customers’ perceptions of the environmental practices in tourism accommodation and their customer experiences and levels of satisfaction. The working hypotheses, based on a review of the literature on environmental sustainability and customer experience in the hospitality industry, are tested in an empirical study of 412 Spanish customers who stayed in various types of tourist accommodation. The main conclusion is that the relationship between environmental sustainability and customer experience in the hospitality industry can be demonstrated. This paper also validates a measurement scale based on the most accepted dimensionality of the construct: cognitive (think), affective (feel), behavioral (act), sensory (sense) and social (relate)

    Generalized Kelvin–Voigt damping models for geometrically nonlinear beams

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    Strain-rate-based damping is investigated in the strong form of the intrinsic equations of three-dimensional geometrically exact beams. Kelvin–Voigt damping, often limited in the literature to linear or two-dimensional beam models, is generalized to the three-dimensional case, including rigid-body motions. The result is an elegant infinite-dimensional description of geometrically exact beams that facilitates theoretical analysis and sets the baseline for any chosen numerical implementation. In particular, the dissipation rates and equilibrium points of the system are derived for the most general case and for one in which a first-order approximation of the resulting damping terms is taken. Finally, numerical examples are given that validate the resulting model against a nonlinear damped Euler–Bernoulli beam (where detail is given on how an equivalent description using our intrinsic formulation is obtained) and support the analytical results of energy decay rates and equilibrium solutions caused by damping. Throughout the paper, the relevance of damping higher-order terms, arising from the geometrically exact description, to the accurate prediction of its effect on the dynamics of highly flexible structures is highlighted

    Modal-based nonlinear model predictive control for 3D very flexible structures

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    In this paper a novel NMPC scheme is derived, which is tailored to the underlying structure of the intrinsic description of geometrically exact nonlinear beams (in which velocities and strains are primary variables). This is an important class of PDE models whose behaviour is fundamental to the performance of flexible structural systems (e.g., wind turbines, High-Altitude Long-Endurance aircraft). Furthermore, this class contains the much-studied Euler-Bernoulli and Timoshenko beam models, but has significant additional complexity (to capture 3D effects and arbitrarily large displacements) and requires explicit computation of rotations in the PDE dynamics to account for orientation-dependent forces such as gravity. A challenge presented by this formulation is that uncontrollable modes necessarily appear in any finite dimensional approximation to the PDE dynamics. We show, however, that an NMPC scheme can be constructed in which the error introduced by the uncontrollable modes can be explicitly controlled. Furthermore, in challenging numerical examples exhibiting considerable deformation and nonlinear effects, it is demonstrated that the asymptotic error can be made insignificant (from a practical perspective) usingour NMPC scheme and excellent performance is obtained evenwhen applied to a highly resolved numerical simulation of thePDEs. We also present a generalisation of Kelvin-Voigt dampingto the intrinsic description of geometrically-exact beams. Finally,special emphasis is placed on constructing a framework suitablefor real-time NMPC control, where the particular structure ofthe underlying PDEs is exploited to obtain both efficient finite-dimensional models and numerical schemes

    El proceso de adaptación de las empresas de transporte internacional por carretera al transporte marítimo de corta distancia

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    Las empresas de transporte internacional por carretera se configuran como uno de los actores clave en el desarrollo del transporte marítimo de corta distancia. Si su deseo es operar de manera estable, utilizando la opción más eficiente –el transpor- te no acompañado– deben modificar su perfil con el propósito de obtener la máxima rentabilidad. El objetivo de este trabajo reside en analizar este proceso de cambio a partir del estudio de cinco empresas de transporte internacional por carretera que han desarrollado dicha adaptación para convertirse en operadores logísticos multi- modales. Los resultados de la investigación muestran cuatro áreas de cambio clave: reestructuración de la flota, reestructuración de la plantilla de conductores, cambios en el modelo de negocio y establecimiento de una estructura en el país de destinoInternational road haulage companies are seen to be one of the key players in the development of short-distance maritime transport. If they wish to operate in a stable manner, by using the most efficient option – unaccompanied transport – they must modify their profile with the aim of obtaining the greatest cost-effectiveness. The aim of this work is to analyse this process of change by studying five international road haulage companies that have undertaken such an adaptation in order to become multimodal logistics operators. The findings of the research show four key areas of change: restructuring of the fleet, restructuring of the workforce of drivers, changes in the business model, and setting up a structure in the destination countr

    Aeroelastic control and estimation with a minimal nonlinear modal description

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    Modal-based, nonlinear Moving Horizon Estimation (MHE) and Model Predictive Control(MPC) strategies for very flexible aeroelastic systems are presented. They are underpinned by an aeroelastic model built from a 1D intrinsic (based on strains and velocities) description of geometrically-nonlinear beams and an unsteady Vortex Lattice aerodynamic model. Construction of a nonlinear, modal-based, reduced order model of the aeroelastic system, employing a state-space realisation of the linearised aerodynamics around an arbitrary reference point, allows us to capture the main nonlinear geometrical couplings at a very low computational cost. Embedding this model in both MHE and MPC strategies, which solve the system continuous-time adjoints efficiently to compute sensitivities, lays the foundations for real-time estimation and control of highly flexible aeroelastic systems. Finally, the performance and versatility of the framework operating in the nonlinear regime is demonstrated on two very flexible wing models, with notably different dynamics, and on two different control setups: a gust-load alleviation problem on a very high aspect ratio wing with slower dynamics, which involves substantial deflections; and flutter suppression on a flexible wing with significantly faster dynamics, where an unconventional nonlinear stabilisation mechanism is unveiled

    Impacto ambiental de la virtualización de las carreras de grado

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    La virtualización de la educación superior propone una solución a la demanda de infraestructura áulica necesaria para cubrir la creciente actividad académica así como el desarrollo pleno de las misiones y funciones de las instituciones de educación superior. A pesar de constituirse en la última década en la opción preferida para el apoyo de la enseñanza presencial, el estudio de la implementación de la educación virtual ofrece reducidos abordajes sobre su impacto ambiental. La falta de información sobre la sostenibilidad de esta actividad deja abierto el interrogante sobre la necesidad de desarrollar prácticas compensatorias a fin de mitigar sus efectos. El propósito de nuestro trabajo es aplicar indicadores internacionales a fin de determinar la sostenibilidad ambiental de la virtualización de espacios curriculares correspondientes al último año de una carrera de grado en una universidad argentina de gestión pública. En el marco del Programa "Tecnología y Responsabilidad Social" de las Facultades de Ingeniería y de Ciencias Económicas y Sociales (UNMDP) se presentan los resultados de la investigación empírica estableciendo una reducción de la emisión directa de gases efecto invernadero por la disminución de movilidad docente y estudiantil en oposición al incremento de emisiones indirectas por consumo energético y acceso a internet.Fil: Zanfrillo, Alicia Inés. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Esteban, Alejandra M. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; Argentina.Fil: Artola, María Antonia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

    The integration of the immigrants in spain and its regions

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    Este artículo presenta un novedoso sistema de medición de la integración de las personas inmigrantes en las regiones españolas. Complementando en varios aspectos la iniciativa lanzada años atrás por las instituciones europeas (Declaración de Zaragoza), el sistema de medición propuesto comprende 24 indicadores que abarcan cuatro áreas: la situación laboral; las relaciones sociales e intergrupales; el bienestar individual, y el acceso a derechos de ciudadanía. Basándose en un amplio abanico de fuentes secundarias, consigue algo inédito: una completa cobertura estadística a escala infraestatal. El sistema sienta las bases para un seguimiento longitudinal y su ejecución con datos de 2011 permite comprobar el impacto de los primeros años de crisis económica sobre la integración de la población inmigrante. Los resultados señalan cierta ambivalencia, con una situación crecientemente desfavorecida de las personas inmigrantes en los ámbitos de Empleo y Bienestar, en comparación con la población nativa. En cambio, en los ámbitos de Ciudadanía y Relaciones Sociales se observa una evolución positiva, incluso en el periodo de recesión económica. La naturaleza polifacética de estos procesos y las disparidades territoriales dan lugar a tres perfiles regionales distintos.Peer Reviewe
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