54 research outputs found

    Who Pays for our Clothing from Lidl and KiK?

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    A report on the impact of buying practices of retail discounters Lidl and KiK on wages and working conditions in six selected suppliers in Bangladesh, as well as in German retailing as a whole

    An interaction abstraction toolkit for public display applications

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    Tese de doutoramento em Tecnologias e Sistemas de InformaçãoPublic digital displays have become increasingly ubiquitous in our technological landscape. Considering their flexibility and communication potential, public displays can become an important communication channel and even reach the attention, usage, and relevance that smartphones have today. Interaction with public displays is recognised as a key element in making them more engaging and valuable, but most public display systems still do not support any interactive feature. A key reason behind this apparent paradox is the lack of efficient and clear abstractions for incorporating interactivity into public display applications. While interaction can be achieved for a specific display system with a particular interaction modality, the lack of proper interaction abstractions means that there is too much specific work that needs to be done outside the core application functionality to support even basic forms of interaction. In this work, we investigate and develop interaction abstractions for public displays. We start by analysing public displays from the point of view of the information that results from the various interactions and that can be used to drive several types of content adaptation behaviour on public displays. We call this information digital footprints, and the result is a framework that maps digital footprints to adaptation strategies and to interaction mechanisms. This framework can be used by display designers to help them choose the interaction mechanisms that a display should support in order to be able to collect a given set of footprints, creating more relevant displays that are able to automatically adapt to their environment. We then identify and characterise interaction tasks and controls that are appropriate for public display interaction. This analysis results in a design space that can form the foundation of interaction toolkits, giving system developers with a reference for the types of high-level tasks and controls that can be incorporated into a toolkit. Finally, we design, implement, and evaluate a software toolkit of interaction abstractions for public display applications – the PuReWidgets toolkit. Programmers can use this toolkit to easily incorporate interactive features into their web-based public display applications. PuReWidgets provides high-level abstractions that shield programmers from the low-level details of the interaction mechanisms. We evaluate this toolkit along various dimensions. First, we evaluate the system’s performance. We then evaluate the API’s flexibility and capabilities using our own experience in developing interactive applications with it. We also evaluate the API’s usability from the perspective of independent programmers. Finally, we provide an evaluation of the resulting system’s usability from the perspective of an end-user interacting with a real-world deployment of a public display. The evaluation results indicate that PuReWidgets is an efficient, usable, and flexible toolkit for web-based interactive public display applications. By making this toolkit publicly available, we hope to promote the development of more and newer kinds of interactive public display applications inside and, more importantly, outside the research community.Os ecrãs públicos digitais estão cada vez mais presentes na nossa paisagem tecnológica. Considerando a sua flexibilidade e capacidade de ligação em rede, os ecrãs públicos têm o potencial para se tornarem num importante canal de comunicação e talvez até atingir a atenção, utilização e relevância que os smartphones têm hoje em dia. A interactividade dos ecrãs públicos ´e reconhecida como um elemento chave para os tornar mais atractivos e valiosos, mas a maioria dos sistemas de ecrãs públicos actuais ainda não suporta nenhuma forma de interação. Uma razão por detrás deste aparente paradoxo é a falta de abstrações claras e eficientes para incorporar interactividade nas aplicações para ecrãs públicos. Apesar de a interação poder ser conseguida para sistemas específicos, com uma modalidade de interação específica, a falta de abstrações de interação apropriadas significa que ´e necessário demasiado trabalho específico fora das funcionalidades nucleares da aplicação para suportar ate as formas mais básicas de interação. Neste trabalho, investigamos e desenvolvemos abstrações de interação para ecrãs públicos. Começamos por analisar os ecrãs públicos do ponto de vista da informação que resulta das interações e de que forma pode ser utilizada em procedimentos de adaptação de conteúdo para ecrãs públicos. Chamamos a esta informação digital footprints, e o resultado é uma estrutura conceptual que mapeia as digital footprints em estratégias de adaptação e em mecanismos de interação. Esta estrutura pode ser utilizada por designers de ecrãs públicos para ajudar a escolher os mecanismos de interação que um determinado ecrã deve suportar de forma a poder recolher um determinado conjunto de digital footprints, criando assim ecrãs com conteúdos mais relevantes e que são capazes de se adaptar ao seu ambiente social. De seguida, identificamos e caracterizamos tarefas de interação e controlos apropriados para interação com ecrãs públicos. Esta análise resulta num espaço de desenho que pode servir de base para toolkits de interação, dando uma referência aos designers do sistema para os tipos de controlos que podem ser incorporados no toolkit. Finalmente, projectamos, implementamos e avaliamos um toolkit de abstrações de interação para aplicações para ecrãs públicos – o toolkit PuReWidgets. Os programadores podem utilizar este toolkit para incorporar facilmente funcionalidades interactivas nas suas aplicações, baseadas na web, para ecrãs públicos. O PuReWidgets fornece abstrações de alto nível que protegem os programadores dos detalhes de baixo nível associados aos mecanismos de interação. O toolkit é avaliado segundo várias dimensões. Primeiro, avaliamos o desempenho do sistema. De seguida, avaliamos a flexibilidade e capacidades da API, usando a nossa própria experiencia no desenvolvimento de aplicações interactivas. Avaliamos também a usabilidade da API da perspectiva de programadores independentes. Finalmente, avaliamos o toolkit da perspectiva dos utilizadores que interagem com um ecrã público num ambiente real. Os resultados da avaliação indicam que o PuReWidgets é um toolkit eficiente, flexível e usável para aplicações interactivas para ecrãs públicos. Ao tornar este toolkit disponível publicamente, esperamos promover o desenvolvimento de mais aplicações interactivas para ecrãs públicos dentro e, mais importante, fora da comunidade de investigação.This research was supported by the Funda¸c˜ao para a Ciˆencia e Tecnologia (FCT) PhD training grant SFRH/BD/47354/2008. This research has also received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 244011 (PD-Net)

    CO2 Capture and Renewable Energy

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    The urgently needed carbon neutral economy requires a portfolio of strategies, among which, CO2 capture and renewable energy will need to play a decisive role. Dispatchable renewables, such as bioenergy, will play an increasing role in maintaining electricity security, in producing heat in the industry and residential sectors, and in reducing the emissions from the transport sector. Biomethane, also known as a renewable natural gas, can be directly blended with or fully replace natural gas in existing pipelines and end-user equipment, with the added advantage of being carbon neutral. CO2 capture and storage (CCS) will also be of paramount importance in abating CO2 emissions from existing infrastructure in the power and industrial sectors. There are many industries that will be difficult or impossible to decarbonize in the short term, such as the cement sector, in which CO2 emissions are intrinsic to the production process. In such cases, CCS will be mandatory to achieve the goal of net zero emissions. Permanent CO2 removal technologies, such as bioenergy with carbon capture and storage (BECCS) and direct air capture and storage (DACS), will also be necessary in the medium term to compensate for emissions from the hard-to-abate sectors, and in the long term, even to remove atmospheric CO2 from past emissions. This book consists of six peer-reviewed scientific articles that cover a range of high-interest subjects related to the aforementioned hot topics

    Who pays for our clothing from Lidl and Kik?

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    CCC_LIDL_KIK_ENG__3_.pdf: 3030 downloads, before Oct. 1, 2020

    Accountability and narratives in historical settings

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    The critical and interpretative accounting studies on accountability constitute the basis for the development of the three papers of this Ph.D. thesis. Connected from a thematic and a methodological perspective, these three archival based researches explore different aspects of accountability. The attention moves progressively from exploring a retrospective storytelling as an informal media of accountability; to comparing this informal narrative with those contained in the formal media; to finally study different forms through which accountability can be practiced. While the first and the second papers focuses on the role played by stories and narratives in the provision of accountability, the third paper enlarges the focus to explore the relation between narratives and accounting in the provision of accountability. In this thesis accounting is conceived as a discourse where specific rules are applied, a social practice and a technique, that may be used in the accountability discourse

    Le imprese e il social commerce: caratteristiche distintive, potenzialità, opportunità di marketing e sfide manageriali

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    I social media hanno radicalmente modificato le modalità di fruizione del canale online da parte degli utenti, segnando lo sviluppo di un’“era consumer-driven”. Oggi, infatti, i consumatori utilizzano sempre più spesso i media sociali come luoghi privilegiati per condividere informazioni in merito a prodotti, brand ed imprese. Questa forma di cooperazione tra utenti - che si traduce in un legame tra socialità virtuale e shopping online - ha portato all’emergere di una nuova forma di commercio elettronico denominata social commerce. Nato negli Stati Uniti e poi diffusosi in Europa, il social commerce può essere definito come “a form of commerce mediated by social media involving convergence between the online and the offline environments” (Wang e Zhang, 2012). Malgrado il fenomeno sia piuttosto recente, Forrester Research (2011) stima che, entro il 2015, il fatturato generato dal social commerce raggiungerà un valore di 30 miliardi di dollari. Nel corso degli anni il social commerce ha ricevuto molta attenzione sia dagli studiosi sia dai practitioner, perché considerato in grado di modellare la nascita di una nuova modalità di vendita online. Tuttavia, similmente a quanto accaduto più di dieci anni fa con l’emergere del commercio elettronico, il social commerce rappresenta una grande opportunità per le imprese, ma richiede, allo stesso tempo, un importante cambiamento di paradigma nella gestione sia dell’e-commerce sia del brand. Grazie ai social media, infatti, i consumatori possiedono oggi uno strumento semplice, veloce e a basso costo sia per soddisfare il bisogno di reperire informazioni prima di effettuare un acquisto, sia per condividere l’esperienza che ne segue. Tale opportunità, offerta dalle nuove tecnologie del Web 2.0, garantisce ai clienti un maggior potere nella relazione con il brand e con le imprese proprio perché aumentano esponenzialmente le opportunità di reperire informazioni ed il numero di alternative, canali e punti vendita in cui poter effettuare l’acquisto. Per le imprese, quindi, è necessario assumere piena consapevolezza del cambiamento in atto, in modo tale da gestirlo proattivamente. In tal senso, diviene prioritario comprendere le dinamiche sociali online, conoscere le piattaforme di condivisione, gli individui più influenti in Rete e ripensare la propria strategia di business e di comunicazione in un’ottica consumer-centrica. Oggi, la letteratura sull’argomento è ancora piuttosto limitata. Di conseguenza, questo lavoro intende fornire un contributo al filone di studi sul social commerce attraverso una prima esplorazione, dal punto di vista degli esperti di digital marketing, delle caratteristiche distintive, delle potenzialità, delle principali opportunità di marketing e delle sfide manageriali e organizzative che il suddetto fenomeno dischiude alle imprese attive nel marketspace, con particolare focus sul nostro Paese. L’Italia, infatti, se da una parte pone specifiche criticità dovute al relativo ritardo nella diffusione dell’e-commerce, dall’altra, rappresenta un contesto particolarmente propizio per i social media. Ciò si traduce nella possibilità di utilizzare il social commerce quale driver di sviluppo delle vendite online nel nostro Paese

    Industrial Energy Management and Sustainability

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    Growing environmental concerns caused by increasing consumption of naturalresources and pollution need to be addressed. Manufacturing dictates the efficiencywith which resource inputs are transformed into economically valuableoutputs in the form of products and services. Consequently, it is also responsiblefor the resulting waste and pollution generated from this transformation process.As a matter of fact, about one-third of the global total energy consumption isassociated withmanufacturing activities; thus, achieving higher energy efficiencyin this sector has been the focus of research as well as of policy and industrialprogrammes in recent years. In particular, being able to effectively manageenergy and energy-related activities has proved to be a fundamental capabilityfor companies willing to improve their sustainability, as it constitutes the first,critical step to understanding their processes and to identifying and correctlyevaluating improvement opportunities.This Special Issue focuses on energy management and sustainability of bothmanufacturing processes and systems, including methods, practices, tools, applicationsand experiences

    Carbon Management for Sustainable Development: An examination of potential transition paths for the Saudi Arabian ‘national system of innovation’ towards a cleaner energy economy

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    PhDSince the first industrial revolution, rising carbon emissions have caused harmful effects on our environment. There is a broad consensus that climate change is happening and that it is as a result of anthropogenic carbon emissions, primarily from burning fossil fuels. This raises concern for the future of our carbon-based world energy and world economy, particularly with economies heavily dependent on oil, such as Saudi Arabia. This dissertation aims to answer the question: How could Saudi Arabia, given its oil-based economy and vast oil reserves, respond to the challenges of climate change and the world’s transitioning towards environmental sustainability, and away from fossil fuels. Two studies have been conducted, a quantitative study and a qualitative study. The first study examined the Saudi energy sector, 40 life cycle assessment (LCA) studies on both carbon capture and storage (CCS) and solar photovoltaic (Solar PV) were used to create 12 scenarios for 3 growth cases from year 2010 to 2025. Results showed massive reductions in carbon dioxide emissions in all scenarios. The second study examined the economy of Saudi Arabia, using 30 interviews with participants from across the economy, to materialise the Saudi national system of innovation. Major forces of the economy and their relationships have been identified and discussed. Using both studies, transition paths of the Saudi NSI towards a sustainable and cleaner energy economy were then constructed and discussed. A Saudi sustainable carbon management ‘system of innovation’ (SSCMSI) was proposed. Given Saudi Arabia’s heavy dependence on oil, which characterised its NSI fabric, constructing an NSI around its energy sector was important. The proposed SSCMSI role includes: accelerating innovation in the energy sector, encouraging energy efficiency, accelerating the use of renewable energy, improving market conditions, supporting technology transfer from advanced economies, utilising international cooperation and mobilizing private sector investment in energy.Yamani Cultural and Charitable Foundation YCCF scholarshi

    Axisymmetric simulation codes for hall effect thrusters and plasma plumes

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    Mención Internacional en el título de doctorThe development of reliable and versatile plasma discharges simulation codes is becoming of central importance, given the rapidly evolving electric propulsion landscape. These tools are essential for facilitating and complementing the design of new prototypes, signiffcantly reducing development time and costs. Moreover, they can provide a deeper insight on already proven technologies, revealing optimization opportunities so as to improve the thruster performance and lifetime, and predicting the operational parameters at different regimes of interest. This Thesis is devoted to the numerical study of different plasma discharges and, in particular, the Hall effect thruster (HET) discharge. With special focus on particle-based modeling, two simulation codes have been developed. The first one, named HYPHEN, is a new two-dimensional axisymmetric hybrid, particle-in-cell (PIC)/fluid multi-thruster simulation platform. Its versatile PIC-based module for heavy species supports the simulation of inner active surfaces, mixed specular-diffuse neutral-wall reflection, and chargeexchange (CEX) collisions, thus extending the code capabilities and enabling the simulation of axisymmetric plasma plumes. Moreover, it features a new population control which monitors independently every heavy species and limits the statistical noise at a low computational cost. Furthermore, an improved version of the HET electron fluid module for the isotropic electron pressure case is presented. Three major studies have been carried out with this code. First, the simulation of an ion thruster plasma plume has permitted to benchmark HYPHEN against the 3D plasma plume code EP2PLUS. Second, an investigation on the neutral-wall interaction effects on an unmagnetized plasma discharge in a surface-dominated cylindrical channel with isothermal electrons has been performed. The discharge ignition requires different propellant injection mass ows in the diffuse and specular neutral-wall reflection cases. Third, preliminary simulations of a SPT-100 HET have been carried out to demonstrate the code capabilities and reveal its limitations. Consistent results have been obtained for different cathode locations in the near plume region and various electron turbulent transport parameter profiles. The second code corresponds to a new version of the one-dimensional radial particle model of a HET discharge, originally developed by F. Taccogna. The major improvements are an ionization controlled discharge algorithm, which enables sustaining a steady-state discharge, and an extended volumetric weighting algorithm which provides a more accurate macroscopic description of the low populated species, such as the wall-emitted secondary electrons. The radial dynamics of both the primary and secondary electron populations have been analyzed in detail, assessing the temperature anisotropy ratio of their velocity distribution functions and the asymmetries introduced by cylindrical geometry effects in the macroscopic laws of interest, thus aiming at a future improvement of the plasma-wall interaction module implemented in HYPHEN.El desarrollo de códigos fiables y versátiles para la simulación de descargas de plasma es cada vez más importante dada la rápida evolución de la propulsión espacial eléctrica. Estas herramientas son esenciales para facilitar y complementar el diseño de nuevos prototipos, reduciendo significativamente los tiempos y costes de desarrollo. Además, pueden ampliar la comprensión de las tecnologías ya establecidas, revelar vías de optimización del propulsor que permitan mejorar su rendimiento y vida útil, y predecir los parámetros de operación del mismo en diferentes regímenes de interés. Esta Tesis está dedicada al estudio numérico de diferentes descargas de plasma y, en particular, de descargas HET. Se han desarrollado dos códigos de simulación, con especial énfasis en los modelos de partículas. El primero de ellos, llamado HYPHEN, es una nueva plataforma de simulación multi-propulsor, híbrida PIC/fluida y axisimétrica. Su módulo PIC para especies pesadas permite la simulación de superficies activas inmersas en el plasma, procesos de reflexión especular-difuso de neutros en pared y colisiones CEX, extendiendo por tanto las capacidades del código y permitiendo la simulación de plumas de plasma axisimétricas. Además, incluye un nuevo control de población que monitoriza a cada especie pesada por separado limitando el ruido estadístico y el coste computacional. Por otra parte, se presenta una versión mejorada del modelo fluido de electrones isótropos para HET. Tres estudios principales se han llevado a cabo con este código. En primer lugar, la simulación de la pluma de plasma de un motor iónico ha permitido validar HYPHEN con el código de plumas 3D EP2PLUS. Por otro lado, se ha investigado el efecto de la interacción del gas neutro con la pared en una descarga no magnetizada con electrones isotermos en un canal cilíndrico esbelto. La ignición de la descarga requiere inyectar diferentes gastos másicos de propulsante en los casos de reflexión difusa y especular. En tercer lugar, se han realizado simulaciones preliminares de un motor HET de tipo SPT- 100 con el objeto de demostrar las capacidades del código y revelar sus limitaciones, obteniendo resultados consistentes para diferentes posiciones del cátodo en la región de la pluma cercana, y perfies del parámetro de turbulencia de electrones. El segundo código representa una nueva versión del modelo radial de partículas de una descarga HET desarrollado originalmente por F. Taccogna. Las principales mejoras consisten en un algoritmo de control de la descarga a través de la ionización, que permite obtener una descarga estacionaria, y un algoritmo de pesado volumétrico extendido, que proporciona una descripción macroscópica más precisa de las especies poco pobladas, como los electrones secundarios emitidos desde las paredes del motor. Para posibilitar una futura mejora del módulo de HYPHEN de interacción plasma-pared, se han analizado en detalle la dinámica radial de los electrones primarios y secundarios, la anisotropía de temperatura de sus funciones de distribución de velocidad, y las asimetrías cilíndricas en las leyes macroscópicas de interés.Programa Oficial de Doctorado en Mecánica de Fluidos por la Universidad Carlos III de Madrid; la Universidad de Jaén; la Universidad de Zaragoza; la Universidad Nacional de Educación a Distancia; la Universidad Politécnica de Madrid y la Universidad Rovira i Virgili.Presidente: Iván Calvo Rubio.- Secretario: Gonzalo Sánchez Arriaga.- Vocal: Daniela Pedrin
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