265 research outputs found

    Setting Long Distance WiFi Records: Proofing Solutions for Rural Connectivity

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    802.11 WiFi technology is commonly used for creating wireless networks with a range of about one hundred meters. With careful planning and proper antennas, this same equipment can be used to make point-to-multipoint links of tens of kilometers and point-to-point links of hundreds of kilometers. This paper presents some experiments at distances of up to 382 kilometer  that were performed in Venezuela from April 206 to July 2007, as well as an affordable instrument setup for long distance antenna alignment.La tecnología conocida como WiFi, basada en el estándar 802.11 se usa comúnmente para crear redes inalámbricas con alcance de un centenar de metros. Haciéndole las modificaciones apropiadas y utilizando antenas adecuadas los mismos dispositivos pueden utilizarse  para establecer redes punto-multipunto de decenas de kilómetros y enlaces punto a punto de centenares de kilómetros.  Este artículo presenta algunos experimentos a distancias de hasta 382 kilómetros realizados en Venezuela entre abril del 2006 y julio de 2007, así como una técnica de alineación de antenas para larga distancia utilizando instrumentos de bajo costo

    Energy-efficient Internet of Things monitoring with low-capacity devices

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    The Internet of Things (IoT) allows users to gather data from the physical environment. While sensors in public spaces are already widely used, users are reluctant to deploy sensors for shared data at their homes. The deployment of IoT nodes at the users premises presents privacy issues regarding who can access to their data once it is sent to the Cloud which the users cannot control. In this paper we present an energy-efficient and low cost solution for environmental monitoring at the users home. Our system is built completely with open source components and is easy to reproduce. We leverage the infrastructure and trust of a community network to store and control the access to the monitored data. We tested our solution during several months on different low-capacity single board computers (SBC) and it showed to be stable. Our results suggest that this solution could become a permanently running service in SBCs at the users homes.Peer ReviewedPostprint (author's final draft

    TV White Spaces: A Pragmatic Approach

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    190 pages The editors and publisher have taken due care in preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information contained herein. Links to websites imply neither responsibility for, nor approval of, the information contained in those other web sites on the part of ICTP. No intellectual property rights are transferred to ICTP via this book, and the authors/readers will be free to use the given material for educational purposes.  e ICTP will not transfer rights to other organizations, nor will it be used for any commercial purposes. ICTP is not to endorse or sponsor any particular commercial product, service or activity mentioned in this book. This book is released under the Attribution-NonCommercial-NoDerivatives ¦.þ International license. For more details regarding your rights to use and redistribute this work, see http://creativecommons.org/licenses/by-nc-nd/4.0/

    Renewable Energy Infrastructure. Importance to Reach Sustainability goals. The Venezuelan Situation in 2016

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    Renewable energy is fundamental for economic growth and sustainable development. To be generated, distributed and used renewable energy requires proper infrastructure. Venezuela is a country with important energy resources, mainly in hydropower, but despite the huge resources invested in the improvement of its infrastructure, the delays with projects' completion as well as the frequent blackouts show that there is a structural problem that hinders the attainment of the Energy for All Global Goals. This article presents an overview of the Venezuelan renewable energy potential, its importance to meet sustainability goals, some construction problems affecting this sector and the situation of renewable infrastructure in construction in the country. The conclusions highlight a complex problem whose solution requires deep changes in the Venezuelan energy policies and strategies

    Pasture pork, strategies for minimizing environmental impact

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    The environmental impact of pastured pork production systems is related to climate, soil type, vegetative ground cover species and grazing pressure. Each situation requires a specific analysis. Different strategies have proven to be beneficial to reduce the environmental impact of pastured pork, including: implementing rotational management, employing an appropriate stocking rate, periodically moving shelters, feeding and drinking structures, and utilizing crops for soil bioremediation. In order to maintain a vegetative ground cover of 75%, it is advisable to implement rotational grazing systems with stocking rates lower than 50 growing-finishing pigs/ha or 10 gestating sows/ha

    Renewable energy infrastructure. A challenge for Venezuelan industrial construction

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    The relevance of renewable energy has grown significantly in our global society. Important efforts are oriented to sustain it. Renewable energy depends on different technical, financial environmental and social complex processes. From the point of view of industrial construction sector this research evaluates some of the current trends in energy generation and use in Venezuela as well as environmental consequences and risks that derive from these. Additionally, authors highlight the importance of infrastructure as key issue to sustain renewable energy generation and use. The study present references of some energy renewable projects in process in Venezuela and the main problems that constrain their performance. Conclusions evidence the complex nature of industrial construction and suggest the need to improve industrial construction competitivenes as a strategy oriented to enhance renewable energy offer in the country. Additionally it is proposed to all stakeholders to work toghether to correct the conditions that currently limit industrial construction development. This is part of ongoing research

    Protein functional features extracted from primary sequences: A focus on disordered sequences.

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    In this thesis we implement an ensemble of sequence analysis strategies aimed at identifying functional and structural protein features. The first part of this work was dedicated to two case studies of specific proteins analyzed to provide candidate func

    Constraints to the competitiveness of industrial construction. A case study of Venezuelan oil and petrochemical sector

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    The challenges of today's world require individuals and companies to improve their performance levels as a mechanism to achieve better living conditions and a coherent economic and social development. Therefore, one of the main objectives of the European Union is to become the worlds most competitive and dynamic economy based on knowledge, capable to reach sustainable economic growth with more and better jobs and greater social cohesion. Commission of the European Communities (2003). However, even with such a global reference and important examples on international markets, not all local scenarios present the conditions needed to achieve the growth, development and proper use of knowledge. The Venezuelan case, currently widely discussed due to the contradictory currents that analyze national socio-economic performance is one that, on a pattern that seems contrary to global trends, shows signs of weakening of the productive sector. Therefore, in seeking long-term solutions, it is necessary to analyze: What happens with the Venezuelan competitive performance? Why does its industrial sector present a behavior apparently opposed to global trends? What are the limitations that prevent its own players to develop the maximum potential of the country? How can current trends be corrected

    Modelo de Gestión del Conocimiento para la Competitividad del Sector de las Construcciones Petroleras, Petroquímicas y Energéticas Venezolanas

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    La construcción es una de las actividades más valiosas para la sociedad debido a la naturaleza de los servicios que ofrece y por el volumen de empleos y movimiento económico que genera. Por ello es un elemento fundamental para el desarrollo sustentable. Es una industria compleja, cada vez más dependiente del conocimiento. Debido a su naturaleza fragmentaria y temporal y la alta rotación de personal presenta grandes retos y complicaciones particulares. Estas dificultades en oportunidades pueden transformarse en problemas por la complejidad, localización geográfica o los requisitos técnicos, financieros e innovaciones de los proyectos. Debido a sus características, las construcciones sufren cambios en las condiciones planificadas. Con frecuencia estos cambios conducen a retrasos en la ejecución de los proyectos, costes superiores a los presupuestados y conflictos entre los clientes y los ejecutores. Esto genera problemas de competitividad que afectan tanto a países desarrollados como países en vías de desarrollo. Los problemas de la construcción tienen perniciosos efectos para la sociedad, que pierde recursos que deberían permitir mejores resultados en términos de calidad de vida y beneficios sociales y económicos. Debido a la importancia del sector y los ingentes recursos que se invierten en cada proyecto se justifican los máximos esfuerzos para lograr los mejores desempeños de esta industria. Éste interés ha orientado el desarrollo de investigaciones, para apoyar el logro de los objetivos de mejoramiento continuo y construcción sustentable. Los estudios desarrollados han permitido demostrar el valor añadido del conocimiento en todos los sectores productivos. Para la construcción, los conocimientos ofrecen indicadores de desempeño, datos y lecciones aprendidas provenientes de aciertos y errores. Estos deben conducir a aprendizajes fundamentales para sustentar su competitividad. Sin embargo, a pesar de los conocimientos disponibles y los avances en las técnicas de control gerencial y de proyectos, es alarmante la recurrencia de los problemas de construcción. Esta problemática se manifiesta con severidad en los proyectos de construcción industrial que se desarrollan para el sector petrolero, petroquímico y energético venezolano. El sector presenta evidentes necesidades para un mejor desempeño competitivo por la alta incidencia de retrasos de los proyectos, que implican pérdidas de gran parte de los recursos humanos, financieros, técnicos y conocimientos invertidos. Esta investigación plantea como objetivos analizar la importancia de la construcción y su sustentabilidad, los principales problemas que afectan el sector, la gestión del conocimiento y algunos modelos disponibles para gestionarlos. Igualmente examina las lecciones aprendidas y la productividad y competitividad, con particular atención a los problemas de competitividad venezolanos. Adicionalmente se evalúan las implicaciones del conocimiento como activo estratégico y se caracterizan las empresas de construcción industrial venezolanas. Para ello se identifican las dimensiones que sustentan la gestión del conocimiento en estas empresas, para finalmente determinar las que resultan más idóneas para el nuevo modelo a ser propuesto. Con estos objetivos se desarrolló el estudio empírico. Para ello fueron invitados a participar representantes de 105 empresas y expertos de construcción distintos, todos con experiencias de construcción al sector industrial venezolano. Se obtuvieron 112 respuestas en representación de 41 organizaciones y expertos diferentes. El trabajo de campo inició en Junio de 2012 y culminó en Noviembre de 2012. Los datos obtenidos fueron analizados con apoyo de técnicas estadísticas descriptivas y multivariables. Los objetivos de la investigación se alcanzaron ya que se logró caracterizar el sector de las construcciones industriales y se propuso un nuevo modelo de gestión del conocimiento adecuado a sus características. El nuevo modelo fue formulado atendiendo a criterios de sencillez, bajos costes y facilidad de adaptación para motivar su utilización en organizaciones de construcción industrial variadas. Con ello se busca que resulte de utilidad aún para las organizaciones más pequeñas, con menores recursos o aquellas que enfrentan entornos constructivos complicados. Por último se presentan algunas sugerencias para motivar la comprensión de los fenómenos estudiados en los grupos de interés de la construcción. Se propone analizar estos problemas desde las etapas iniciales de los estudios de ingeniería, de arquitectura, de construcción, de economía y administración. Igualmente se propone desarrollar acciones conjuntas de parte de los sectores académicos, gubernamentales, industriales y asociaciones para el mejoramiento competitivo y desarrollo sustentable global. La propuesta aporta datos sobre el sector constructivo venezolano en un área que presenta grandes carencias y propone un modelo innovador por su sencillez y orientación hacia el uso diario e intuitivo de los conocimientos como recursos fundamentales para la competitividad. Esta orientación puede tener trascendencia más allá del sector descrito, para apoyar la solución de problemas de otras industrias en entornos globales. ABSTRACT Construction is one of the most valuable activities for society due to the nature of the services offered and the number of jobs and revenues generated. Therefore it is a key element for sustainable development. Construction is a complex industry increasingly dependent on knowledge. Its temporary and fragmentary nature and the high staff turnover present great challenges and particular complications to construction. In some cases these conditions may evolve to serious problems because of the complexity, geographic location or even technical, financial and innovative requirements of each project. Due to their characteristics, constructions frequently undergo changes in planned conditions. Often these changes lead to delays in project completion, costs higher than budgeted and conflicts between clients and performers. This creates problems of competitiveness affecting both developed and developing countries. The construction problems have harmful effects on society, since it loses resources that would otherwise allow better results in terms of quality of life and social and economic benefits. The importance and the enormous resources invested in each project justify the efforts to achieve the best performance of this industry. This interest has guided the development of multiple research efforts to support the achievement of construction performance improvements and sustainable construction. The studies carried out have demonstrated the added value of knowledge in all productive sectors. For construction, knowledge offers performance indicators, data and lessons learned from successes and failures. These should lead to fundamental learning to sustain sector competitiveness. However, despite the available knowledge and advances in techniques and project management control, the recurrence of construction problems is alarming. This problem shows itself severely in industrial construction projects that are developed for the Venezuelan oil, petrochemical and energy sectors. These sectors have evident needs for better competitive performance because of the high incidence of project delays, involving loss of much of the human, financial, technical and knowledge resources invested. This research analyzes the importance of construction and sustainability, the main problems affecting the sector, knowledge and some models available to manage them. It also examines the lessons learned and the productivity and competitiveness, with particular attention to the problems of Venezuelan competitiveness. Additionally, the Venezuelan industrial construction companies are characterized evaluating the implications of knowledge as an strategic asset for construction. Moreover, the research evaluates the dimensions that support knowledge management in these companies, to finally identify those that are the most suitable for the new model to be proposed. With these objectives in mind the empirical study was developed. 105 different companies and experts with Venezuelan industrial construction experiences were invited to participate on the survey. 112 responses were obtained representing 41 different organizations and experts. Fieldwork started in June 2012 and ended in November 2012. The data obtained was analyzed with descriptive and multivariate statistical techniques. The research objectives were achieved since the industrial construction sector was characterized and a new management model was proposed based on the particular characteristics of these companies. The new model was formulated according to the criteria of simplicity, low cost and ease of adaptation. This was performed to motivate the use of the new model in various industrial construction organizations, even in smaller companies, with limited resources or those facing complex construction environments. Finally some suggestions to encourage understanding of the phenomena studied among construction stakeholders were proposed. The importance of studying these problems at an early stage of the engineering, architectural, construction, economic and administration studies is highlighted. Additionally, academic, government, industrial organizations and associations are invited to join efforts to improve the competitive and sustainable global development. The proposal provides data on the Venezuelan construction sector in an area that has large gaps and proposes a model which is innovative for its simplicity and suggests the daily and intuitive use of knowledge resources as a key issue to competitiveness. This orientation may have implications beyond the described sector to support the solution of problems of other industries in a global environment
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