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Borquez-Paredes, D., Beghelli, A., Leiva, A., & Murrugarra, R. (2018). Does fragmentation avoidance improve the performance of dynamic spectrum allocation in elastic optical networks? Photonic Netw. Commun., 35(3), 287–299.
Abstract: Most spectrum allocation algorithms in elastic optical networks apply a greedy approach: A new connection is allocated as long as there are enough spectrum slots to accommodate it. Recently, a different approach was proposed. Named Deadlock-Avoidance (DA), it only establishes a new connection if the portion of spectrum left after allocating it is zero (full-link utilization) or is big enough to accommodate future requests. Otherwise, the connection request is blocked as a way to avoid fragmentation. The performance of DA has been evaluated in a single-link scenario, where its performance is not affected by the slot continuity constraint. In this paper, we evaluate for the first time the blocking performance and fragmentation level of DA in a fully dynamic network scenario with different bitrates and number of slots for a single link, a 4-node bus and a mesh topology. The performance was evaluated by simulation, and a lower bound was also derived using a continuous Markov chain model. Results are obtained for DA and three greedy algorithms: First Fit, Exact Fit and First-Last Fit. Results show that DA significantly decreases fragmentation, and thus, it exhibits a much lower blocking due to fragmentation than the greedy algorithms. However, this decrease is compensated by a new type of blocking due to the selective acceptance of connections. As a result, the extra computational complexity of DA does not compensate a gain in performance.
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Garmendia, M. L., Mondschein, S., Matus, O., Murrugarra, R., & Uauy, R. (2017). Predictors of gestational weight gain among Chilean pregnant women: The Chilean Maternal and Infant Nutrition Cohort study. Health Care Women Int., 38(8), 892–904.
Abstract: We identified factors associated with gestational weight gain (GWG) in 1,654 Chilean pregnant women with full-term pregnancies. At baseline, we collected information about sociodemographic, gyneco-obstetric, anthropometric, and health-care-related factors. We found that prepregnancy nutritional body mass index was the most important factor related to GWG above recommendations (overweight: ratio of relative risks [RRR] = 2.31, 95% confidence interval [CI, 1.73, 3.09] and obesity: RRR = 2.90, 95% CI [2.08, 4.03]). We believe that women who are overweight/obese at the beginning of pregnancy should be identified because of their higher risk, and that adequate strategies should be designed and implemented to help them achieve a healthy GWG.
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Murrugarra, R., Wallace, W., & Yushimito, W. (2021). The effect of consistency in estimating link travel times: A data fusion approach. Transport. Plan. Techn., 44(6), 608–628.
Abstract: Although attention to data fusion has undergone rapid growth since the late 1980s, there are still relatively few applications in transportation management. Most research has based fusion weight estimation on the variance of each data source, assigning high weights to low variance data, implying that low variance means high accuracy. We propose a data fusion methodology where weights are assigned in a way data variance and sensor bias are minimized, but also consistency among data sources is maximized. The proposed methodology is flexible to work with multiple data sources, with different reliability and variability, and under different traffic conditions. The inclusion of consistency is shown to be statistically significant during special events and incidents and demonstrates its validity in successfully representing changes in traffic patterns by reasonably estimating their magnitude. Results from a case study that validate this method are shown.
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Murrugarra, R. I., & Wallace, W. A. (2015). The Effect of a Stand-Alone Ethics Course in Chilean Engineering Students' Attitudes. IEEE Commun. Mag., 53(11), 30–34.
Abstract: Engineering ethics education is taking on increasing importance worldwide, but in Chile the percentage of universities that have a mandatory course concerning ethics is still small. Traditionally, Chilean universities with existing ethics courses teach them using a philosophical or theological perspective, limited to occidental theories, and usually from a Christian point of view. This article studies the impact of a new methodology and technique to teach ethics in Chile: case-based, non-normative, and with a critical-descriptive approach. An empirical study is conducted to assess the relative impact of an ethics class on students individual and inherent moral values and attitudes, and understand the factors that contribute to this impact. Results indicate that even though the importance of religion in Chile is decreasing, it is still a major source of students' ethical principles and moral values. In addition, results suggest that a change in moral values develops when discussions among groups with different points of view occur.
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