19,042 research outputs found

    Social aspects of place experience in nomadic work/life practices

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    This chapter examines the importance of “where” mobile work/life practices occur. By discussing excerpts of data collected through in-depth interviews with mobile professionals, we focus on the importance of place for mobility, and highlight the social character of place and the intrinsically social motivations of workers when making decisions regarding where to move. In order to show how the experience of mobility is grounded within place as a socially significant con- struct, we concentrate on three analytical themes: place as an essential component of social/collaborative work, place as expressive of organizational needs and characteristics, and place as facilitating a blending of work/life strategies and relationships

    Decision Support for Smart Grid Planning and Operation Considering Reliability

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    [ES] Esta tesis aporta contribuciones a los temas de los sistemas de energía y la movilidad eléctrica. Por lo tanto, se proponen soluciones innovadoras para la planificación de la red de distribución radial tradicional sin o con pocas unidades de recursos energéticos distribuidos, y para la planificación, operación, reconfiguración, y gestión de recursos energéticos en redes de distribución en media tensión considerando una alta penetración de los recursos energéticos distribuidos en el contexto de las redes inteligentes. Las preocupaciones sobre la disponibilidad de combustibles fósiles y el aumento de los efectos climático causados por su uso generalizado en la generación de electricidad han llevado a varias políticas e incentivos para atenuar estos problemas. Estas medidas contribuyeron a inversiones considerables en fuentes de energía renovables y motivaron muchas iniciativas de redes inteligentes. Aunque el panorama futuro de los sistemas eléctricos modernos parece muy prometedor, la integración a gran escala de fuentes de energía renovables de naturaleza intermitente, como la eólica y la fotovoltaica, plantea nuevos desafíos y limitaciones en la industria eléctrica actual. Hoy en día, el diseño de la red de distribución no está correctamente preparado para alojar una gran cantidad de fuentes de energía renovables distribuidas. Por lo tanto, los operadores del sistema de distribución reconocen la necesidad de cambiar el diseño de la red mediante la planificación y el refuerzo. A medida que aumenta la penetración de las fuentes de energía renovable, un agregador de energía puede proporcionar una generación y demanda altamente flexibles según lo requiere el paradigma de red inteligente. Además, esta entidad puede permitir lograr una alta integración de la oferta de energía renovable y aumentar el valor para los pequeños productores y consumidores que no pueden negociar directamente en el mercado mayorista. Sin embargo, la entidad agregadora de energía necesita herramientas adecuadas de apoyo a la decisión para superar los desafíos complejos y hacer frente a un gran número de recursos energéticos. Por lo tanto, la gestión de recursos energéticos es crucial para que la entidad agregadora de energía reduzca los costos de operación, aumente de los beneficios, reduzca la huella de carbono y mejore la estabilidad del sistema. En la perspectiva mundial actual, muchas personas se están mudando a las ciudades en busca de una mejor calidad de vida, contribuyendo de esta manera a la continua expansión de las áreas urbanas. En consecuencia, el sector de transportes está jugando un papel crítico en las emisiones de dióxido de carbono. Teniendo en cuenta esto, muchas ventajas medioambientales y económicas pueden ser obtenidas del cambio de los motores de combustión interna a los vehículos eléctricos. Sin embargo, este cambio contribuirá a una carga en la red de distribución, dando lugar a la posibilidad de congestión de la red. Por lo tanto, para facilitar la integración de la carga de los vehículos eléctricos en la red de distribución, un modelo de predicción del comportamiento del usuario de un vehículo eléctrico pode ser una herramienta muy importante. Además, el paradigma de la red inteligente está desafiando la estructura de control y operación convencional diseñado para redes de distribución pasivas. De este modo, la reconfiguración de la red de distribución será una estrategia esencial y significativa para el operador del sistema de distribución. En el estado del arte actual se identificó una falta de modelos, estrategias y herramientas de apoyo a la toma de decisiones adecuadas para los dominios de problemas de planificación, operación y gestión de recursos energéticos de redes de distribución en media tensión con una alta penetración de fuentes de energía distribuidas. Por lo tanto, surgen varios desafíos de investigación que llevan a la necesidad de desarrollar modelos nuevos e innovadores que aborden: a) el impacto de las fuentes de energía renovable y la variabilidad de la demanda en la planificación de la expansión a largo plazo, b) el problema de la gestión de los recursos energéticos a gran escala, teniendo en cuenta la demanda, las fuentes de energía renovables, los vehículos eléctricos y la variabilidad de los precios del mercado, c) el análisis de impacto de los precios de carga dinámicos de los vehículos eléctricos en la operación de la red de distribución y en el comportamiento del usuario del vehículo eléctrico. Además, en el contexto de la red de distribución de media tensión radial tradicional, también se verificó la necesidad de modelos innovadores para mejorar la confiabilidad a través de la identificación de nuevas inversiones en los componentes de la red. Por lo tanto, esta tesis propone soluciones innovadoras para hacer frente a todos estos vacíos y problemas. Para ese propósito, las contribuciones de la tesis, resultan en un innovador sistema de apoyo a la decisión llamado Advanced Decision Support Tool for Smart Grid Planning and Operation (SupporGrid). El SupporGrid se compone de un conjunto de modelos diversificados que juntos contribuyen a manejar la complejidad de la planificación tradicional de las redes de distribución radial (PlanTGrid), y para la planificación (PlanSGrid), operación (OperSGrid), y los problemas de gestión de recursos energéticos (ERMGrid) en redes de distribución de media tensión en el paradigma de red inteligente. PlanTGrid incluye un modelo de planificación de expansión para redes de distribución radial tradicionales para identificar la posibilidad de nuevas inversiones al costo mínimo. La planificación de la expansión a largo plazo de las redes de distribución en un contexto de red inteligente con una alta penetración de fuentes de energía renovables distribuidas y que trata las fuentes de incertidumbre se resuelve mediante el uso PlanSGrid. OperSGrid contiene una herramienta de simulación de viajes de los usuarios de los vehículos eléctricos funcionando en conjunto con un modelo de operación y reconfiguración que utiliza descomposición de Benders y precios marginales para comprender el impacto del precio de carga de energía dinámica en ambos lados: la red de distribución y el usuario de vehículo eléctrico. Para hacer frente a la gestión de recursos energéticos a gran escala con problemas de respuesta a la demanda y sistemas de almacenamiento de energía, así como con la variabilidad de la demanda, las fuentes de energía renovable, los vehículos eléctricos y el precio de mercado, ERMGrid incluye un modelo estocástico de dos etapas. Las metodologías desarrolladas para el sistema de soporte de decisiones se han probado y validado en escenarios realistas. Los resultados prometedores logrados en condiciones realistas respaldan la hipótesis de que las metodologías son adecuadas e innovadoras para la planificación de la red de distribución radial tradicional, y para la planificación, operación, reconfiguración y gestión de recursos energéticos a largo plazo de la red de distribución considerando alta penetración de recursos energéticos distribuidos y de vehículos eléctricos en el contexto de red inteligente. Los resultados prometedores logrados en condiciones realistas respaldan la hipótesis de que las metodologías son adecuadas e innovadoras para la planificación de la red de distribución radial tradicional, y para la planificación, operación, reconfiguración y gestión de recursos energéticos a largo plazo de la red de distribución considerando la alta distribución de recursos energéticos y la penetración de vehículos eléctricos. De hecho, este sistema de apoyo a la decisión mejorará el funcionamiento de las redes de distribución de media tensión, permitiendo ahorros para las partes interesadas

    National Culture\u27s Impact on Effectiveness of Supply Chain Disruption Management

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    The purpose of this research is to understand the national cultural antecedents that may help explain differences in supply chain disruptions mitigation abilities of companies from different countries. An analysis of survey data on disruption planning and response collected from various organizations worldwide was performed using weighted least square regression and factor analysis. We find that culture influences disruption planning and response. Statistical findings suggest that differences in disruption planning and response abilities between companies from different countries could be partly attributed to national culture. All five Hofstede’s dimensions of national culture, i.e., Power Distance, Individualism, Masculinity, Uncertainty Avoidance, and Long-term Orientation were shown to have a significant positive effect on disruption planning and response. National cultural dimensions and economic status of a country could be effectively used to predict disruption planning and response abilities of companies in various countries. Managers could benefit from our research as it could help them assess disruptions mitigation abilities of their partners located in other countries. Increasing international trade and globalization of supply chains accentuate the importance of our research

    No. 09: Transnationalism and African Immigration to South Africa

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    The demise of formal apartheid has created new and as yet only partially understood opportunities for migration to South Africa. Legal migration from other Southern African Development Community (SADC) countries, for example, has increased almost ten-fold since 1990 to over four million visitors per year. South Africa’s (re)insertion into the global economy has brought new streams of legal and undocumented migrants from outside the SADC region and new ethnic constellations within. The easing of legal and unauthorized entry to South Africa has made the country a new destination for African asylum-seekers, long-distance traders, entrepreneurs, students and professionals (Bouillon 1996; Saasa 1996; Rogerson 1997; de la Hunt 1998; Peberdy and Crush 1998; Ramphele 1999). SAMP aims to explore the migration phenomenon from a variety of disciplinary and methodological perspectives and at a number of different spatial scales. At one end of the research spectrum are the project’s statistically representative, quantitative, national surveys in source and host countries (Sechaba Consultants 1997; de Vletter 1998; Frayne and Pendleton 1998; McDonald et al 1998, 1999; Mattes et al 1999; McDonald 2000). These surveys have provided important baseline data on cross-border migration at a panregional scale. They have also helped to contest the crude misrepresentations of xenophobic discourse (Croucher 1998; McDonald et al 1998; Crush 1999a). But the large sample sizes and structured questionnaire instruments necessarily sacrifice the more nuanced information that can only be gleaned from local case studies of an ethnographic, participatory and place-based nature. What is the qualitative nature of the new South African migratory mosaic? Who are the new international migrants and immigrants in South Africa? What are the conditions shaping their migratory patterns? And what is the nature of their relations with South Africans and their home countries? We are also interested in some of the broader conceptual and theoretical questions prompted by these movements. While they may be relatively new to South Africa (and that itself is an issue for debate), they are not altogether new movements. The global “age of migration” has, by virtue of the sequestering effect of apartheid, come late to the country (Castles and Miller 1993; Cohen 1995; Sassen 1999). The conceptual and analytical debates that have swirled around the issue of migration and globalization elsewhere have largely by-passed South Africa. The question, therefore, is whether the tools for understanding the age of migration have any explanatory purchase on the South African empirical material. Whether South and Southern Africa can actually be a source of theorizing, as they have been in the past, is another question. Three major themes are addressed in this paper: (a) the changing character of cross-border migration to South Africa; (b) the value of the conceptual apparatus of transnationalism to describe and research changing forms of cross-border migration into South Africa; and (c) the spatial reconfiguration and emergence of new migrant spaces in the country. Each of these themes is discussed briefly below

    Optimising and adapting the QoS of a dynamic set of inter-dependent tasks

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    Due to the growing complexity and adaptability requirements of real-time systems, which often exhibit unrestricted Quality of Service (QoS) inter-dependencies among supported services and user-imposed quality constraints, it is increasingly difficult to optimise the level of service of a dynamic task set within an useful and bounded time. This is even more difficult when intending to benefit from the full potential of an open distributed cooperating environment, where service characteristics are not known beforehand and tasks may be inter-dependent. This paper focuses on optimising a dynamic local set of inter-dependent tasks that can be executed at varying levels of QoS to achieve an efficient resource usage that is constantly adapted to the specific constraints of devices and users, nature of executing tasks and dynamically changing system conditions. Extensive simulations demonstrate that the proposed anytime algorithms are able to quickly find a good initial solution and effectively optimise the rate at which the quality of the current solution improves as the algorithms are given more time to run, with a minimum overhead when compared against their traditional versions

    Assessing transport accessibility for healthcare facility reconfiguration using GIS and multilevel modelling

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    Transport accessibility to healthcare facilities is a major issue in the United Kingdom, as recently demonstrated by the shift away from providing healthcare in acute hospitals to care closer to home . Common measures of accessibility focus on the creation of distance or travel time contours around a destination and devote less attention to individual differences such as user perceptions, their transport usage, and area-wide factors including income deprivation, safety and security. Failure to account for such factors may result in imperfect decision making in terms of healthcare relocation and reconfiguration. This thesis therefore aims to develop a user-based accessibility model by focusing on both individual socio-economic (e.g. age, gender, access to transport modes) and area-wide characteristics (e.g. income deprivation, public transport provision, safety and security). In order to identify important factors that affect accessibility and to develop the user-based accessibility model, two revealed preference questionnaire surveys were undertaken at Loughborough and Hinckley. The purpose of the first questionnaire was to understand underlying factors affecting accessibility to a healthcare facility. The results revealed that both individual and area-wide factors affect transport accessibility to a healthcare facility. The purpose of the second questionnaire was conducted to capture data relating to users perception of accessibility and their socio-economic factors so as to develop a user-perception based accessibility model. Network-based travel time and travel distance as well as public transport provision data from a respondent home to a healthcare facility were generated using a GIS technique. Individual-level questionnaire data were then integrated with the other secondary datasets (e.g. Census, Index of Multiple Deprivation, Accidents) using postcodes of survey respondents. Both single-level and multilevel mixed-effects linear regression models were employed to develop a relationship between user-perceptions relating to accessibility and the factors influencing accessibility. Multilevel models that can control data from the two levels (i.e. individuals nested within local areas) provided better goodness-of-fit statistics compared with those of single-level regression models. The results indicate that travel distance by car, number of available direct bus services, age, and destination choices affect user-perceptions of accessibility to a healthcare facility. For instance, if travel distance by car increases by one mile then the perception of accessibility to a healthcare facility decreases by four units (on a scale of 0-100). Surprisingly, many area-wide factors such as security and safety, income deprivation were found to be statistically insignificant. In order to see which healthcare facility is more accessible, calibrated multilevel models along with number of people within the catchment area were then employed to predict the overall accessibility score related to a healthcare facility. This is important for policy makers in healthcare facility relocation and reconfiguration with respect to user perception of transport accessibility. Also it would be valuable to organisations that need to make decisions based on their users perceptions who are the real decision makers as to whether to use a facility or not

    Musical preferences and technologies: Contemporary material and symbolic distinctions criticised

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    Today how individuals interact with various cultural items is not perfectly consistent with theoretical frameworks of influential scholars on cultural consumption, such as Bourdieu (1984), Gans (1999), and Peterson and Simkus (1992). One such variation is in the ever increasing variety of technological modes to acquire and listen to music (Pinch and Bijsterveld, 2004). However, as a consequence of digital divides (van Dijk, 2006), technological items may not be distributed equally among social groups. At present, the value of status-making through a preference for different genres of music extends itself to different forms of consumption and ways of experiencing music. We are yet to fully understand the power these practices have on generating status. This article is therefore motivated by the need to integrate within quantitative frameworks of taste and cultural consumption, an analysis of individuals’ technological engagement. These two dimensions, integrated as components of musical practices, enhance our understanding of cultural boundaries across different social groups.The objective is to bridge a gap detected in the literature, addressing the following questions: Are technological modes to listen to music related to musical tastes

    The evolution of retail banking services in United Kingdom: a retrospective analysis

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    The purpose of this paper is to assess the sequence of technological changes occurred in the retail banking sector of the United Kingdom against the emergence of customer services by developing an evolutionary argument. The historical paradigm of Information Technology provides useful insights into the ‘learning opportunities’ that opened the way to endogenous changes in the banking activity such as the reconfiguration of its organizational structure and the diversification of the product line. The central idea of this paper is that innovation never occurs without simultaneous structural change. Thus, a defining property of the banking activity is the diachronic adaptation of formal and informal practices to an evolving technological dimension reflecting the extent to which the diffusion of innovation (re)generates variety of micro level processes and induces industry evolution.Information Technology; Retail Banking; History of Technology; Innovation Systems.
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