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Imagen de apoyo de Improving Performance in Industrial Internet of Things Using Multi-Radio Nodes and Multiple Gateways

Por: Ricardo Javier Arjona Angarita | Fecha: 2017

IEEE 802.15.4e is emerging as a robust standard for industrial Internet of Things. This standard is particularly effective for low power, multi-hop networks, and typically supports applications with low throughput. However, with the advances in energy harvesting, the need for supporting better performing solutions is also gaining momentum. This paper presents and analyses a modified link scheduling algorithm for IEEE 802.15.4e based solutions. Three approaches are considered. With the first approach, only the gateway node is equipped with multiple radios. With the second approach, non-gateway nodes are equipped with multiple radios as well. With the third approach, multiple single radio gateways are considered. Results from simulations have been presented to demonstrate the improvement in performance compared to the typical single radio, single gateway deployments.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería

Imagen de apoyo de Technology in Northwest Amazonia (NWA) views of views : sustainability, environmental management and territorial ordering. A contribution to a Political Ecology for Northwest Amazonia

Por: Oscar Alfredo Forero Larrañaga | Fecha: 2002

This essay continues with a discussion concerning the intersection between indigenous technological adoption/adaptation and the range of perspectives with respect to local communities’ use of technology in general. Analytical instruments will be presented at the end of this article. First, however, the reader will have the opportunity to examine the ‘views’ of outsiders with respect to the debate surrounding sustainability, environmental management and territorial ordering. Responses to an on-line survey concerning the above issues together with my own comments, will add to the discussion.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ciencias sociales

Imagen de apoyo de Climate change vulnerability assessment of the urban forest in three Canadian cities

Por: Camilo; Duinker Ordoñez Barona | Fecha: 2015

Climate change is a likely addition to the unpredictable challenges urban communities will face. Enhancing urban forests has gained prominence as a climate adaptation tool in cities. The fact that urban forests are also vulnerable is now starting to emerge. Many urban forest management professionals do not know how to take climate change into account and what aspects of urban forest vulnerability to climate change to prioritize. Bringing climate change to the forefront of the decision-making process in urban forest management, and urban forests to the forefront of urban climate issues, is important to urban forest success. This paper presents an exploratory assessment of vulnerability to climate change in the Canadian urban forests of Halifax, London, and Saskatoon. The objectives of the assessment were to: 1) identify the elements of urban forest exposure and sensitivity to climate change, the nature of the expected impact, and the adaptive capacities that exist in these three urban forests. 2) assess which of these elements contributes more to urban forest vulnerability to climate change. 3) elicit adaptive strategies based on this information. The method used was participatory and expert-based and allowed for a systematic evaluation of vulnerability. Exposures related to drought, heat stress, and wind, susceptibility of urban trees to insects and diseases, and the sensitivity of young trees and tree species with specific temperature and moisture requirements, are the main concerns regarding the vulnerability of urban forests to climate change in these three cities.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Ecological integrity in urban forests

Por: Camilo; Duinker Ordóñez Barona | Fecha: 2012

Ecological integrity has been an umbrella concept guiding ecosystem management for several decades. Though plenty of definitions of ecological integrity exist, the concept is best understood through related concepts, chiefly, ecosystem health, biodiversity, native species, stressors, resilience and self-maintenance. Discussions on how ecological integrity may be relevant to complex human-nature ecosystems, besides those set aside for conservation, are growing in number. In the case of urban forests, no significant effort has yet been made to address the holistic concept of ecological integrity for the urban forest system. Preliminary connections between goals such as increasing tree health, maintaining canopy cover, and reducing anthropogenic stressors and the general notion of integrity exist. However, other related concepts, such as increasing biodiversity, the planting of native species, and the full meaning of ecosystem health beyond merely tree health have not been addressed profoundly as contributors to urban forest integrity. Meanwhile, other concepts such as resilience to change and self-maintenance are not addressed explicitly. In this paper we reveal two camps of interpretation of ecological integrity for urban forests that in turn rely on a particular definition of the urban forest ecosystem and a set of urban forest values. Convergence and integration of these values is necessary to bring a constructive frame of interpretation of ecological integrity to guide urban forest management into the future.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Bio-inspired cognitive architecture for adaptive agents based on an evolutionary approach

Por: Oscar Javier; Antonio Jiménez Romero López | Fecha: 2008

In this work, an hybrid, self-configurable, multilayered and evolutionary subsumption architecture for cognitive agents is developed. Each layer of the multilayered architecture is modeled by one different Reinforcement Machine Learning System (RMLS) based on bio-inspired techniques. In this research an evolutionary mechanism based on Gene Expression Programming to self-configure the behaviour arbitration between layers is suggested. In addition, a co-evolutionary mechanism to evolve behaviours in an independent and parallel fashion is used too. The proposed approach was tested in an animat environment (artificial life) using a multi-agent platform and it exhibited several learning capabilities and emergent properties for self-configuring internal agent’s architecture.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería

Imagen de apoyo de Transpolitics and ICTs: an ethnography of Colocolombians in London = Transpolitica y TICs: una etnografía de los colombianos en Londres

Por: Julián Andrés Riveros Clavijo | Fecha: 2014

Abstract: Through participant observation, digital ethnography, and in-depth interviews, I examine how first generation Colombian immigrants in London use ICTs to participate in politics, both in Colombia and the UK. In Conclusion, I have observed that only highly educated Colombian immigrants use the Internet to participate in politics.Additionally, the reasons that explain the ways they use Internet to engage in politics are two: first, as a way to bypass political systems and institutionalism, and second, to reconnect with the political life of their home country. Resumen: Usando Observación participante, etnografía digital y entrevistas a profundidad, Examino en este artículo cómo algunos inmigrantes colombianos en Londres usan TICs para participar en política, tanto en Colombia como en Gran Bretaña. En conclusión, observamos que únicamente los colombianos altamente educados utilizan internet para participar en política. Adicionalmente, las razonas que explican las formas en que lo usan son dos: primero, como una forma de evitar el sistema político y el institucionalismo, segundo, para reconectarse con la vida política del país que dejaron atrás.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Low thermal conductivity and improved thermoelectric performance of nanocrystalline silicon germanium films by sputtering

Por: Jaime Andrés; Romero Pérez Taborda | Fecha: 2016

Si x Ge 1? x alloys are well-known thermoelectric materials with a high figure of merit at high temperatures. In this work, metal-induced crystallization (MIC) has been used to grow Si 0.8 Ge 0.2 films that present improved thermoelectric performance (zT= 5.6× 10? 4 at room temperature)—according to previously reported values on films—with a relatively large power factor (? centerdot S 2= 16 ?W centerdot m? 1 centerdot K? 2). More importantly, a reduction in the thermal conductivity at room temperature (?= 1.13±0.12 W.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Analysis of emergent properties in a hybrid bio-inspired architecture for cognitive agents

Por: Oscar Javier; Antonio Jiménez Romero López | Fecha: 2007

In this work, a hybrid, self-configurable, multilayered and evolutio-nary architecture for cognitive agents is developed. Each layer of the subsump-tion architecture is modeled by one different Machine Learning System MLS based on bio-inspired techniques. In this research an evolutionary mechanism supported on Gene Expression Programming to self-configure the behaviour arbitration between layers is suggested. In addition, a co-evolutionary mechan-ism to evolve behaviours in an independent and parallel fashion is used. The proposed approach was tested in an animat environment using a multi-agent platform and it exhibited several learning capabilities and emergent properties for self-configuring internal agent’s architecture.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería

Imagen de apoyo de A Case on a Case: Embedding Sustainable Entrepreneurship Into a Managerial-Skills Course

Por: Orlando Enrique; Rodríguez Contreras Pacheco | Fecha: 2015

This paper documents the experience of bringing a real-business challenge into the classroom using a case that demonstrates an issue in a local utility company: the Bucaramanga Metropolitan Aqueduct. The local case study shows the dilemma the manager of a public utilities company must confront, faced with the poor impact of the bottled water business unit on income results. On the one hand, the Board of Directors is totally oriented toward financial results and perceives interesting business potential with the massive development of this product in the region. On the other hand, the natural discussion about taking advantage of that potential and what the company should do in terms of strategy tends to omit its true purpose and the strong policy of social responsibility, which should go against a business that is continually being challenged in terms of the destruction of social and environmental value that it generates (bottled water). Then, this challenge appeals to the innovative sense of the students in the Managerial Skills course of the Industrial Engineering program at the Industrial University of Santander by using active innovation methodologies such as teaching through case studies and design thinking in order to formulate different alternative business models for bottled water so that, along the lines of the actual purpose of the organization, they are able to generate, simultaneously, financial results as well as good environmental and social outcomes. The contribution of this case study centers on the validity of the results generated in terms of acceptance, motivation, and learning by making combined use of concepts such as sustainability, entrepreneurship, and education in innovation. The fact that it is a known, everyday company increased the levels of participation at the time of the respective feedback, and presumably, the students' ability to understand the concepts related to the shared value creation in new ventures creation today.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros

Imagen de apoyo de Fine pitch copper pillar interconnection with C4 (mass reflow) processing

Por: Fernando Roa Vargas | Fecha: 2014

Flip chip interconnection design and process capability has been extended with the use of copper pillar, specially for finer pitches, beyond what was possible with area array and standard C4 reflow and solder bumps. Many trends in device packaging are fueling this trend, specially the needs for thin packaging, increased function integration, challenging thermal, mechanical and physical specifications. In terms of processing, devices using Cu Pillar are most commonly assembled using thermo-compression bonding due to sizable challenges in extending the conventional mass reflow solution, typical for solder bumps. TC is specially recommended for handling very thin die in sparse or peripheral bump layouts, which are a predominant share of all devices converting to Cu pillar, where a bonding head is used to both hold the die flat and in true alignment with the substrate while supplying the thermal energy necessary to complete the interconnection. This process most often also requires the use of a non-conductive paste/film for stress absorption in recognition to the fact that underfill materials have great limitations in filling the underdie cavity. In this paper, we explore avenues to extend the current processing envelope for Cu pillar bumped devices using C4 reflow. Benefits of this approach are shown as decreased cost of ownership for materials, lower fixed costs due to using mostly depreciated equipment. Yet, challenges in defining new design rules, reformulating materials and extending process flows are among some of the barriers for further adoption of this solution in production.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos

Temas:
Otros
Ingeniería