Examinando por Autor "Zarama, Roberto"
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- PublicaciónSólo datosBenchmarking seeding strategies for spreading processes in social networks: an interplay between influencers, topologies and sizes(Scientific Reports, 2020-02-28) Montes, Felipe; Jaramillo, Ana María; Meisel, Jose D.; Diaz-Guilera, Albert; Valdivia, Juan A.; Sarmiento, Olga L.; Zarama, RobertoThe explosion of network science has permitted an understanding of how the structure of social networks affects the dynamics of social contagion. In community-based interventions with spill-over effects, identifying influential spreaders may be harnessed to increase the spreading efficiency of social contagion, in terms of time needed to spread all the largest connected component of the network. Several strategies have been proved to be efficient using only data and simulation-based models in specific network topologies without a consensus of an overall result. Hence, the purpose of this paper is to benchmark the spreading efficiency of seeding strategies related to network structural properties and sizes. We simulate spreading processes on empirical and simulated social networks within a wide range of densities, clustering coefficients, and sizes. We also propose three new decentralized seeding strategies that are structurally different from well-known strategies: community hubs, ambassadors, and random hubs. We observe that the efficiency ranking of strategies varies with the network structure. In general, for sparse networks with community structure, decentralized influencers are suitable for increasing the spreading efficiency. By contrast, when the networks are denser, centralized influencers outperform. These results provide a framework for selecting efficient strategies according to different contexts in which social networks emerge.
- PublicaciónSólo datosNetwork analysis of collaboration in networked universities(Kybernetes, 2021-06-01) Meisel, Jose D.; Montes, Felipe; Ramírez, Angie M.; Lemoine, Pablo D.; Valdivia, Juan A.; Zarama, RobertoPurpose In Latin America and the Caribbean, the access of students to higher education has presented an extraordinary growth over the past fifteen years. This rapid growth has presented a challenge for increasing the system resources and capabilities while maintaining its quality. As a result, the networked universities (NUs) organized themselves as a collaborative network, and they have become an interesting model for facing the complexity driven by globalization, rapidly changing technology, dynamic growth of knowledge and highly specialized areas of expertise. In this article, we studied the NU named Red Universitaria Mutis (Red Mutis) with the aim of characterizing the collaboration and integration structure of the network. Design/methodology/approach Network analytic methods (visual analysis, positional analysis and a stochastic network method) were used to characterize the organizational structure and robustness of the network, and to identify what variables or structural tendencies are related to the likelihood that specific areas of a university would collaborate. Findings Red Mutis is a good example of regional NUs that could take advantage of the strengths, partnerships, information and knowledge of the regional and international universities that form the network. Analyses showed that Red Mutis has a differentiated structure consisting of academic and non-academic university areas with a vertical coordination (by steering and management) of the different university areas. Originality/value The methodology could be used as a framework to analyze and strengthen other strategic alliances between universities and as a model for the development of other NU in local and global contexts.
- PublicaciónSólo datosNetwork analysis of collaboration in networked universities(Kybernetes, 2021-06-01) Meisel, Jose D.; Montes, Felipe; Ramírez, Angie M.; Lemoine, Pablo D.; Valdivia, Juan A.; Zarama, RobertoPurpose In Latin America and the Caribbean, the access of students to higher education has presented an extraordinary growth over the past fifteen years. This rapid growth has presented a challenge for increasing the system resources and capabilities while maintaining its quality. As a result, the networked universities (NUs) organized themselves as a collaborative network, and they have become an interesting model for facing the complexity driven by globalization, rapidly changing technology, dynamic growth of knowledge and highly specialized areas of expertise. In this article, we studied the NU named Red Universitaria Mutis (Red Mutis) with the aim of characterizing the collaboration and integration structure of the network. Design/methodology/approach Network analytic methods (visual analysis, positional analysis and a stochastic network method) were used to characterize the organizational structure and robustness of the network, and to identify what variables or structural tendencies are related to the likelihood that specific areas of a university would collaborate. Findings Red Mutis is a good example of regional NUs that could take advantage of the strengths, partnerships, information and knowledge of the regional and international universities that form the network. Analyses showed that Red Mutis has a differentiated structure consisting of academic and non-academic university areas with a vertical coordination (by steering and management) of the different university areas. Originality/value The methodology could be used as a framework to analyze and strengthen other strategic alliances between universities and as a model for the development of other NU in local and global contexts.
- PublicaciónSólo datosTowards a novel model for studying the nutritional stage dynamics of the Colombian population by age and socioeconomic status(PLoS ONE, 2018-02-08) Meisel, Jose D.; Sarmiento, Olga L.; Olaya, Camilo; Lemoine, Pablo D.; Valdivia, Juan A.; Zarama, RobertoLow-and middle-income countries (LMICs) are experiencing a nutritional transition in which the burden of obesity tends to shift towards the lower-socioeconomic status (SES) group. We propose a system dynamics (SD) model for assessing the nutritional stage dynamics of the Colombian urban population by age and SES projected to 2030. This SD model captures the ageing population according to body mass index (BMI) categories and SES. In this model, the transference rates (TRs) between BMI categories by age and SES are estimated using a heuristic based on data obtained from national surveys. The simulation results show that the Colombian population, particularly those aged 20 to 39 years with a lower SES, is moving towards the overweight and obese categories. The TRs for overweight and obese categories in the lower SES group (the mean TR from not overweight to overweight = 0.0215 (per year) and mean TR from overweight to obese = 0.0098 (per year)) are increasing more rapidly than the those in the middle (the mean TR from not overweight to overweight = 0.0162 (per year) and mean TR from overweight to obese = 0.0065 (per year)) and higher SES groups (the mean TR from not overweight to overweight = 0.0166 and mean TR from overweight to obese = 0.0054 (per year)). Additionally, from 2005 to 2010, individuals aged 20 to 39 years had the highest TRs towards the overweight and obese categories (from 0.026 to 0.036 per year and from 0.0064 to 0.012 per year, respectively). The TRs also indicated that children aged 0 to 14 years are moving from the obese to overweight and from the overweight to not overweight categories. These TRs show that the Colombian population is experiencing an SES-related nutritional transition that is affecting the lower SES population. The proposed model could be implemented to assess the nutritional transitions experienced in other LMICs.
- PublicaciónSólo datosUsing agent based modeling to assess the effect of increased Bus Rapid Transit system infrastructure on walking for transportation(Preventive Medicine, 2016-07-01) Lemoine, Pablo D.; Cordovez, Juan Manuel; Zambrano, Juan Manuel; Sarmiento, Olga L.; Meisel, Jose D.; Valdivia, Juan A.; Zarama, RobertoThe effect of transport infrastructure on walking is of interest to researchers because it provides an opportunity, from the public policy point of view, to increase physical activity (PA). We use an agent based model (ABM) to examine the effect of transport infrastructure on walking. Particular relevance is given to assess the effect of the growth of the Bus Rapid Transit (BRT) system in Bogotá on walking. In the ABM agents are assigned a home, work location, and socioeconomic status (SES) based on which they are assigned income for transportation. Individuals must decide between the available modes of transport (i.e., car, taxi, bus, BRT, and walking) as the means of reaching their destination, based on resources and needed travel time. We calibrated the model based on Bogota's 2011 mobility survey. The ABM results are consistent with previous empirical findings, increasing BRT access does indeed increase the number of minutes that individuals walk for transportation, although this effect also depends on the availability of other transport modes. The model indicates a saturation process: as more BRT lanes are added, the increment in minutes walking becomes smaller, and eventually the walking time decreases. Our findings on the potential contribution of the expansion of the BRT system to walking for transportation suggest that ABMs may prove helpful in designing policies to continue promoting walking.