920 research outputs found

    HEH-BMAC: hybrid polling MAC protocol for WBANs operated by human energy harvesting

    Get PDF
    This paper introduces human energy harvesting medium access control (MAC) protocol (HEH-BMAC), a hybrid polling MAC suitable for wireless body area networks powered by human energy harvesting. The proposed protocol combines two different medium access methods, namely polling (ID-polling) and probabilistic contention access, to adapt its operation to the different energy and state (active/inactive) changes that the network nodes may experience due to their random nature and the time variation of the energy harvesting sources. HEH-BMAC exploits the packet inter-arrival time and the energy harvesting rate information of each node to implement an efficient access scheme with different priority levels. In addition, our protocol can be applied dynamically in realistic networks, since it is adaptive to the topology changes, allowing the insertion/removal of wireless sensor nodes. Extensive simulations have been conducted in order to evaluate the protocol performance and study the throughput and energy tradeoffs.Peer ReviewedPostprint (author's final draft

    Multi-technique approach to rockfall monitoring in the Montserrat massif (Catalonia, NE Spain)

    Get PDF
    Montserrat Mountain is located near Barcelona in Catalonia, in the northeast of Spain, and its massif is formed by conglomerate interleaved by siltstone/sandstone with steep slopes very prone to rockfalls. The increasing number of visitors in the monastery area, reaching 2.4 million per year, has highlighted the risk derived from rockfalls for this building area and also for the terrestrial accesses, both roads and the rack railway. A risk mitigation plan has been launched, and its first phase during 2014-2016 has been focused largely on testing several monitoring techniques for their later implementation. The results of the pilot tests, performed as a development from previous sparse experiences and data, are presented together with the first insights obtained. These tests combine four monitoring techniques under different conditions of continuity in space and time domains, which are: displacement monitoring with Ground-based Synthetic Aperture Radar and characterization at slope scale, with an extremely non-uniform atmospheric phase screen due to the stepped topography and atmosphere stratification; Terrestrial Laser Scanner surveys quantifying the frequency of small or even previously unnoticed rockfalls, and monitoring rock block centimetre scale displacements; the monitoring of rock joints implemented through a wireless sensor network with an ad hoc design of ZigBee loggers developed by ICGC; and, finally, monitoring singular rock needles with Total Station.Peer ReviewedPostprint (author's final draft

    Algorithms for advance bandwidth reservation in media production networks

    Get PDF
    Media production generally requires many geographically distributed actors (e.g., production houses, broadcasters, advertisers) to exchange huge amounts of raw video and audio data. Traditional distribution techniques, such as dedicated point-to-point optical links, are highly inefficient in terms of installation time and cost. To improve efficiency, shared media production networks that connect all involved actors over a large geographical area, are currently being deployed. The traffic in such networks is often predictable, as the timing and bandwidth requirements of data transfers are generally known hours or even days in advance. As such, the use of advance bandwidth reservation (AR) can greatly increase resource utilization and cost efficiency. In this paper, we propose an Integer Linear Programming formulation of the bandwidth scheduling problem, which takes into account the specific characteristics of media production networks, is presented. Two novel optimization algorithms based on this model are thoroughly evaluated and compared by means of in-depth simulation results

    Energy-aware dynamic pricing model for cloud environments

    Get PDF
    Energy consumption is a critical operational cost for Cloud providers. However, as commercial providers typically use fixed pricing schemes that are oblivious about the energy costs of running virtual machines, clients are not charged according to their actual energy impact. Some works have proposed energy-aware cost models that are able to capture each client’s real energy usage. However, those models cannot be naturally used for pricing Cloud services, as the energy cost is calculated after the termination of the service, and it depends on decisions taken by the provider, such as the actual placement of the client’s virtual machines. For those reasons, a client cannot estimate in advance how much it will pay. This paper presents a pricing model for virtualized Cloud providers that dynamically derives the energy costs per allocation unit and per work unit for each time period. They account for the energy costs of the provider’s static and dynamic energy consumption by sharing out them according to the virtual resource allocation and the real resource usage of running virtual machines for the corresponding time period. Newly arrived clients during that period can use these costs as a baseline to calculate their expenses in advance as a function of the number of requested allocation and work units. Our results show that providers can get comparable revenue to traditional pricing schemes, while offering to the clients more proportional prices than fixed-price models.Peer ReviewedPostprint (author's final draft

    Terminal Antennas in ACE2

    Get PDF
    The ACE Network of Excellence was a European Commission funded Network of Excellence, which lasted from 2004 to 2007. One of the activities performed by this Network was in the frame of terminal antennas. In this activity, three aspects were covered in three projects: Small antenna technologies, small terminal antenna technologies and benchmarking of small terminal antennas measurement facilities. The overall aim was to identify the newest trends in antenna design and measurement for personal communications devices, and suggest novel solutions and design methodologies for various applications. The results of this work are presented in this paper

    Smartphone picture organization: a hierarchical approach

    Get PDF
    We live in a society where the large majority of the population has a camera-equipped smartphone. In addition, hard drives and cloud storage are getting cheaper and cheaper, leading to a tremendous growth in stored personal photos. Unlike photo collections captured by a digital camera, which typically are pre-processed by the user who organizes them into event-related folders, smartphone pictures are automatically stored in the cloud. As a consequence, photo collections captured by a smartphone are highly unstructured and because smartphones are ubiquitous, they present a larger variability compared to pictures captured by a digital camera. To solve the need of organizing large smartphone photo collections automatically, we propose here a new methodology for hierarchical photo organization into topics and topic-related categories. Our approach successfully estimates latent topics in the pictures by applying probabilistic Latent Semantic Analysis, and automatically assigns a name to each topic by relying on a lexical database. Topic-related categories are then estimated by using a set of topic-specific Convolutional Neuronal Networks. To validate our approach, we ensemble and make public a large dataset of more than 8,000 smartphone pictures from 40 persons. Experimental results demonstrate major user satisfaction with respect to state of the art solutions in terms of organization.Peer ReviewedPreprin

    From i* models to service oriented architecture models

    Get PDF
    Requirements engineering and architectural design are key activities for successful development of software systems. Specifically in the service-oriented development systems there is a gap between the requirements description and architecture design and assessment. This article presents a systematic process for systematically deriving service-oriented architecture from goal-oriented models. This process allows generate candidate architectures based on i* models and helps architects to select a solution using services oriented patterns for both services and components levels. The process is exemplified by applying it in a synthesis metadata and assembly learning objects system.Peer ReviewedPostprint (author’s final draft

    The Semantics of History. Interdisciplinary Categories and Methods for Digital Historical Research

    Get PDF
    This paper aims at introducing and discussing the data modelling and labelling methods for interdisciplinary and digital research in History developed and used by the authors. Our approach suggests the development of a conceptual framework for interdisciplinary research in history as a much-needed strategy to ensure that historians use all vestiges from the past regardless of their origin or support for the construction of historical discourse. By labelling Units of Topography and Actors in a wide range of historical sources and exploiting the obtained data, we use the Monastery of Sant Genís de Rocafort (Martorell, Spain) as a lab example of our method. This should lead researchers to the development of an integrated historical discourse maximizing the potential of interdisciplinary and fair research and minimizing the risks of bias

    Contemporary elderly housing in China and Europe : architecture refurbishing and emotional design

    Get PDF
    This thesis is written under the background of Chinese society. Architecture always develops with adaption to the desires of society. Design is a way to satisfy these social desires. Currently, China is suffering from the aging problems, both of growing aging population and living space quality. Aging problems are calling for more life supports and cares in living space, ensuring the elderly to have a better and healthier life. In addition, China is experiencing big revolutions of architecture. Architecture design is changing the focus from economic factors to humanistic-concerns. Contemporary space is not only a physical object to use, but also a place to experience. In contemporary elderly housing, apart from physical care, emotional care is expected to provide places where the elderly could live safely and happily. Based on series studies of Chinese social situations and problems, this thesis tries to put forward refurbishing and emotional design as new development directions for Chinese contemporary elderly housing adapted to Chinese society. Comparative methodology is applied between Europe and China. European experiences of emotional design in elderly housing refurbishing are studied in both theoretical and practical fields. In the study process, phenomenology are applied as a philosophical way to analyze the relations among human’s perception, emotion and space and to find the nature and meanings of architecture spaces, providing evidence to show the importance of emotional design for the Chinese elderly as well as the society. Emotional design theories of Norman are analyzed to find how to make effective involvements from different levels between objects and human’s emotions, providing basic methodology for emotional design in elderly housing. Apart from these basic studies, specific researches on methodology of emotional design in Chinese contemporary elderly housing refurbishing are realized. Heidegger’s thoughts are analyzed to find the core emotional requirements of living space. Living space originates from human’s desire of dwelling. It is a place that presents the own identities of a community, a place where the elderly could feel safe and free. Based on this concept, Norman’s emotional design approach is applied in architecture field as a guiding methodology to investigate all the possible ways to create effective interactions between the elderly’s emotion and architecture. Corresponding to three emotional involvement levels of visceral, behavior and reflective, architecture could make emotional affect from appearance, functions, and reflections of culture, art and personal value. Related European cases are studied from these three aspects to find the possible ways to realize emotional design in elderly housing, which could provide suggestions to Chinese contemporary elderly housing refurbishing. For Chinese cases, inheriting Chinese cultural identities is particularly discussed. Chinese culture affects a lot Chinese life styles, their perceptions and understanding of the reality. Inheritage of culture generates great and positive emotional resonance for the Chinese elderly. Emotional design and refurbishment in Chinese contemporary elderly housing should be realized with respect to the culture identities. By analyzing the essence of Chinese culture and contemporary architecture cases of Wang Shu, this thesis is trying to find architectural ways to inherit, develop and integrate the essence of Chinese culture in our present time.La tesis está escrita bajo la sociedad china. La arquitectura siempre se desarrolla adaptada a los deseos de la sociedad. El diseño es una forma de expresar y satisfacer los deseos sociales. Hoy en día, China está sufriendo problemas de envejecimiento, tanto por la población como por las cualidades del espacio. Los problemas de envejecimiento exigen más apoyo y cuidados en el espacio vital, lo que garantiza que los ancianos tengan una vida mejor y más saludable. Además, China está pasando grandes revoluciones en su arquitectura. El enfoque arquitectónico ha cambiado pasando de los factores económicos a las preocupaciones humanísticas. El espacio contemporáneo no es solo un objeto físico para usar, sino también un lugar para sentir. Además de los cuidados físicos, la gente mayor está esperando un espacio con más cuidados emocionales donde puedan vivir segura y feliz. Basada en los estudios de problemas y situaciones sociales de China, esta tesis intenta presentar el diseño emocional y rehabilitación como nuevas direcciones de desarrollar las viviendas contemporáneas para gente mayor adaptadas a la sociedad china. Se aplica una metodología comparativa entre Europa y China. Las experiencias europeas de diseño emocional en la rehabilitación de viviendas para gente mayor se estudian tanto en teórica como prácticamente. En este proceso, se aplica la fenomenología como forma de filosofía para analizar las relaciones entre la percepción humana, la emoción y el espacio, así como también para descubrir la naturaleza y el significado de ese espacio, ofreciendo evidencia para mostrar la importancia del diseño emocional para la gente mayor, así como para la sociedad china. Con objeto de investigar la interacción entre los objetos y las emociones humanas, se analice principalmente a las teorías sobre diseño emocional de Donald Norman; se implementa así una metodología básica aplicable al diseño emocional de las viviendas para gente mayor. A partir de estos estudios básicos, se realiza unas investigaciones específicas sobre la metodología del diseño emocional en la rehabilitación de viviendas contemporáneas para gente mayor en China. A partir de los análisis del pensamiento de Heidegger, encontramos cuáles son los requisitos emocionales básicos del espacio vital. El espacio vital se origina en el deseo humano de alojar. Es un lugar que presenta las identidades propias de una comunidad, donde los ancianos pueden sentirse seguros y libres. Basada en este concepto, la idea de Norman se aplica al campo arquitectónico como una metodología de guía para investigar todas las maneras posibles de crear interacciones efectivas entre la arquitectura y la emoción de la gente mayor. Correspondiendo a tres niveles de visceral, conductivo y reflexivo, la arquitectura generará efectos emocionales desde su apariencia, funciones y sus reflejos de la cultura, el arte y los propios valores personales. Los ejemplos europeos relacionados se estudian a partir de estos tres aspectos para encontrar posibles métodos de realización de diseños emocionales en viviendas para gente mayor, lo que podría ofrecer sugerencias para China. En el estudio de los casos chinos, se considerará especialmente la incidencia de la tradición cultural de China. La cultura china afecta los estilos de vida y su forma especifica de percepción y comprensión de la realidad. La correcta utilización e integración de las alusiones a la cultura tradicional en el diseño contemporáneo generará grandes y positivas respuestas emocionales en los ancianos chinos. El diseño emocional y la rehabilitación en viviendas contemporáneas para gente mayor deben realizarse con respecto a las identidades culturales. Con los análisis de la esencia de la cultura china y la arquitectura de WangShu, intenta encontrar formas y metodologías arquitectónicas capaces de integra y desarrollar la esencia de la cultura tradicional china en la época contemporánea
    corecore