Voutssas J.,Autonomous University of Mexico City
Aslib Proceedings: New Information Perspectives | Year: 2012
Purpose: The purpose of this paper is to summarize the current situation of digital preservation and describe the additional main challenges and issues faced in Latin American countries within the framework of the factors of digital preservation. Design/methodology/approach: This paper reviews the literature on existing digital information preservation around the world, and then focuses on Latin American countries. It proposes a framework in which to analyze the situation in developing countries, particularly in Latin America, and summarizes the issues in six preservation factors and seven principles of preservation. Findings: The amount of digital information has increased geometrically without proper knowledge, theories, strategies, policies and proceedings to preserve it. Developed countries and regions have started to create this knowledge and know-how, as well as setting the basis to manage their digital collections within libraries, archives, and other organizations with the aim to preserve them in the long-term. The situation is radically different in Latin America where we found limited research and projects on digital preservation. Practical implications: The problem of the long-term authentic preservation of digital document collections is not a simple technology problem; it is a much more complex one. This paper summarizes the approaches to understand it but further study is required in order to develop a practical strategy and/or plan. It also highlights the importance of raising awareness of digital preservation in Latin America in order to ensure availability in the future. Social implications: Research, planning, initiatives and proper execution in regard to digital collections preservation is extremely limited in Latin American developing countries, thus endangering vast amounts of digital information. There is a serious risk that valuable digital information will not be preserved adequately for future generations. Originality/value: This paper reviews the main challenges for libraries and archives to preserve digital information over the long term and summarizes the main issues to understand and to thwart this problem. It also highlights the often overlooked problem of digital preservation in developing countries, in particular Latin America. © Emerald Group Publishing Limited.
Alfonso L.,Autonomous University of Mexico City
Atmospheric Chemistry and Physics | Year: 2015
In cloud modeling studies, the time evolution of droplet size distributions due to collision-coalescence events is usually modeled with the Smoluchowski coagulation equation, also known as the kinetic collection equation (KCE). However, the KCE is a deterministic equation with no stochastic fluctuations or correlations. Therefore, the full stochastic description of cloud droplet growth in a coalescing system must be obtained from the solution of the multivariate master equation, which models the evolution of the state vector for the number of droplets of a given mass. Unfortunately, due to its complexity, only limited results were obtained for certain types of kernels and monodisperse initial conditions. In this work, a novel numerical algorithm for the solution of the multivariate master equation for stochastic coalescence that works for any type of kernels, multivariate initial conditions and small system sizes is introduced. The performance of the method was seen by comparing the numerically calculated particle mass spectrum with analytical solutions of the master equation obtained for the constant and sum kernels. Correlation coefficients were calculated for the turbulent hydrodynamic kernel, and true stochastic averages were compared with numerical solutions of the kinetic collection equation for that case. The results for collection kernels depending on droplet mass demonstrates that the magnitudes of correlations are significant and must be taken into account when modeling the evolution of a finite volume coalescing system. © 2015 Author(s).
Dieleman H.,Autonomous University of Mexico City
Journal of Cleaner Production | Year: 2013
This article is about cities and climate change, and about ways to make cities more resilient to the effects of climate change. It presents the two dominant strategies of mitigation and adaptation, and goes on to present a systems view on the city in which resilience is the key response to climate change. The article argues that resilience depends on three dimensions or areas: a city's physical form, infrastructure and technology, its people and particular multilevel governance, levels of human connectedness and communal self-reliance, and the innovative capacity as well as the level of inclusion of marginalized groups within the economy. Teaching and training is seen as an important element in strengthening resilience, and the article presents a number of case studies showing the relevance of learning processes as conditions to work successfully in urban networks in the areas mentioned. The article takes organizational learning as its main orientation and presents important concepts such as "reflective action", "learning by doing", "mental maps", the "experiential learning cycle" and the "5 disciplines of the learning organization". This forms the base for the design of concrete educational material. This material is centered on a number of eco-cultural innovations: concrete ideas, technologies, systems or activities that focus on neighborhood-based activities that reinforce the local economy or introduce small-scale technology for water, renewable energy or waste. © 2013 Elsevier Ltd. All rights reserved.
Gonzalez-Olvera M.A.,Autonomous University of Mexico City |
Tang Y.,National Autonomous University of Mexico
IEEE Transactions on Neural Networks | Year: 2010
This brief presents a structure for black-box identification based on continuous-time recurrent neurofuzzy networks for a class of dynamic nonlinear systems. The proposed network catches the dynamics of a system by generating its own states, using only input and output measurements of the system. The training algorithm is based on adaptive observer theory, the stability of the network, the convergence of the training algorithm, and the ultimate bound on the identification error as well as the parameter error are established. Experimental results are included to illustrate the effectiveness of the proposed method. © 2006 IEEE.
Dieleman H.,Autonomous University of Mexico City
Journal of Cleaner Production | Year: 2016
The article presents urban agriculture as a practice that is gaining attention in many cities worldwide, and focuses in particular on the experiences in Mexico City. It first gives a general description of urban agriculture, introduces some conceptual dimensions and presents a policy framework to stimulate agriculture in cities worldwide. It then discusses current practices in the periurban, suburban and interurban parts of Mexico City, and analyses them in terms of their economic, ecological, social and symbolic dimension. The article shows that Mexico City produces some 20% of its own food, but that its importance in economic terms - seen as employment and income generation - is still limited. Its contribution to the ecological infrastructure of the city equally is limited but has potential, as recent policies firmly integrate urban agriculture in environmental policies of the city. An important challenge is to expand urban agriculture to the 22,000 m2 of green roof gardens recently created in the city. In terms of the social dimension, it is observed that Mexico City clearly follows international policy recommendations, invests in capacity building and has policies to help vulnerable groups and women. Finally it addresses the symbolic dimension and observes that this is very important in Mexico City, as urban agriculture is seen as a way to restore some of the pre-Hispanic practices of the Aztecs especially the Floating gardens or Chinampas that have largely been lost due to colonization. Its final conclusion is that a policy to balance the economic, ecological, social and symbolic dimensions of urban agriculture is missing, and that such a policy is important, especially for the periurban zone of the city, where most of the food is produced. © 2016 Elsevier Ltd.