Artículos Ingeniería

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The impact of electromobility in public transport: An estimation of energy consumption using disaggregated data in Santiago, Chile
(2024) Basso, Franco; Feijoo, Felipe; Pezoa, Raúl; Varas, Mauricio; Vidal, Brian
Electromobility in public transport has become a promising way to reduce environmental pollution. Several contributions have sought to estimate the energy consumption of buses in public transport. However, most of these efforts use measurements collected from controlled or simulated experiments, or that do not characterize the entire bus network. Unlike these studies, this article estimates the energy consumption of all the electric buses that circulate in the city of Santiago, Chile, during the studied period using full disaggregated GPS data and empirical measurements on some sensorized electric buses. The methodology considers a feature selection phase and the development of energy consumption prediction models using physics based and machine learning approaches. The performances of both models are compared with each other, and then, the best one is used to measure the impact of electromobility in the city. This analysis allows decision-makers to target investment by determining the buses with higher energy consumption savings in the face of budget constraints.
The impact of lockdown, fatigue, and social interaction on highway demand during the COVID-19 pandemic: The case of Santiago, Chile
(2024) Basso, Franco; Batarce, Marco; Pezoa, Raúl; Villalobos, Matías; Varas, Mauricio
The COVID-19 pandemic, as well as the government measures to curb its spread, have significantly affected mobility. Various studies have investigated behavioral changes across different transport modes accounting for sociodemographic variables, yet the focus has predominantly been on public transportation. This article addresses this gap by quantifying the impact of mobility restrictions on an urban highway in Santiago, Chile. To do so, we develop several econometric models based on panel data, which enable us to assess control measures’ effects while accounting for their spatial heterogeneity. Our computational experiments demonstrate that traffic reductions were more significant among higher-income drivers (1% reduction per each 100,000 pesos increase). Conversely, municipalities with a higher proportion of elderly residents saw less drastic decreases in traffic. Regarding the effectiveness of control measures, we confirm that the lockdown is affected by fatigue and social interaction. The fatigue implies that users do not fulfill the lockdown as time passes, reducing the effect of quarantines by about 50% during October, 2020. The social interaction effect suggests the lockdown is less effective when not all city’s municipalities are restricted to travel, which might be an argument against dynamic or partial lockdowns.
A home hospitalization assignment and routing problem with multiple time windows, mandatory returns and perishable biological samples: A Chilean case study
(2024) Varas, Mauricio; Baesler, Felipe; Basso, Franco; Contreras, Juan Pablo; Pezoa, Raúl; Rojas-Goldsack, María Francisca
The increase in life expectancy and formal care has fostered the demand for home care services, including home hospitalization. For this service, decision-makers must allocate the staff and route the visits as efficiently as possible. To tackle this problem, in this paper, we devise a new mixed-integer programming formulation that incorporates several industry-specific features, including matching patients to medical specialties and synchronized visits of multiple specialists. Moreover, the proposed formulation also includes three features that have not been tackled simultaneously in the previous literature: multiple time windows, mandatory lunch breaks at the hospital, and fast delivery of perishable biological samples. The proposed model can be reduced to a vehicle routing problem with multiple times windows, known as NP-hard. Therefore, for solving large instances, we design a heuristic procedure composed of a constructive heuristic coupled with an improvement heuristic, which builds on a local branching scheme. To test the applicability of our approach, we conduct a case study focusing on the actual operations of Hospital Padre Hurtado of Santiago, Chile. Our computational experiments show that the model provides fully implementable solutions. Moreover, the heuristic procedure provides high-quality routes (regarding quality and solution times), making it a promising alternative to experience-based scheduling methods and state-of-the-art solvers.
Leveraging LLMs for Efficient Topic Reviews
(2024) Gana, Bady; Leiva-Araos, Andres; Allende-Cid, Héctor; García, José
This paper presents the topic review (TR), a novel semi-automatic framework designed to enhance the efficiency and accuracy of literature reviews. By leveraging the capabilities of large language models (LLMs), TR addresses the inefficiencies and error-proneness of traditional review methods, especially in rapidly evolving fields. The framework significantly improves literature review processes by integrating advanced text mining and machine learning techniques. Through a case study approach, TR offers a step-by-step methodology that begins with query generation and refinement, followed by semi-automated text mining to identify relevant articles. LLMs are then employed to extract and categorize key themes and concepts, facilitating an in-depth literature analysis. This approach demonstrates the transformative potential of natural language processing in literature reviews. With an average similarity of 69.56% between generated and indexed keywords, TR effectively manages the growing volume of scientific publications, providing researchers with robust strategies for complex text synthesis and advancing knowledge in various domains. An expert analysis highlights a positive Fleiss’ Kappa score, underscoring the significance and interpretability of the results.
Earthquake-induced landslides coupled to fluvial incision in Andean Patagonia: inferring their effects on landscape at geological time scales
(2022) Morales, Bastian; Lizama, Elizabet; Somos-Valenzuela, Marcelo; Rivera, Diego; Ningshen, Chen
Earthquakes can deeply erode the mountainous landscape through co-seismic landslides, generating large amounts of sediment and debris that are then transported and distributed by rivers, controlling the landscape evolution. We can observe this influence in the Liqui˜ne Ofqui Fault System (LOFS), an active intra-arc fault system extending hundreds of kilometers through the Andes in Chilean Patagonia. For example, on April 21, 2007, a 6.2 Mw earthquake in the Ays´en Fjord triggered over 500 landslides with volumes reaching 12-20 Mm3. Although there is a well-defined seismic cycle, no study has focused on the effects of co-seismic landslides and sedimentary dynamics on the evolution of this mountainous landscape. In this research, we seek to improve the long-term understanding of the interaction between landslides and fluvial incisions in this segment of the Andes. For this reason, we implemented the Landlab-HyLands landscape evolution model (LEM), a hybrid landscape evolution model that allows modeling landslide activity coupled to fluvial incision. We consider the landslides that occurred during the 2007 earthquake as a precedent and simulate nine scenarios of ten seismic cycles over 21,000 years based on the 2100-year seismic cycle of the Holocene documented in this region. We further used multiple uplift rates, sediment erodibility, and m/n constant ratios associated with the current power law to assess this parameterization’s impact on the landscape. According to our results, landslides are a fundamental mechanism in the landscape’s evolution in this region. Deposits derived from landslides can create transitory landscape forms that can intervene in fluvial dynamics. According to our simulations, a significant part of the landslide sediment can remain on the slopes for thousands of years. We identified that parameterization considerably impacts the evolutionary response of the landscape in the evaluated time scale. Low m/n ratios can generate a different evolutionary response than other scenarios because the slopes are constantly driven towards their threshold angle, intensifying the interaction between landslides and fluvial incisions. Based on our analysis and considering the historical record of the Aysen Fjord, we can explain a critical primary control of the LOFS on landscape erosion and sediment production because of the surface seismic cycle. In our study, we demonstrate how the implementation of hybrid LEM can help to infer the contribution of sediments associated with large earthquakes and to improve the understanding of the role of landslides in the evolutionary history of Andean Patagonia. However, we stress that it is essential to advance in capturing erodibility and incision parameters of the current power law in the Andes and local geomechanical information. Finally, we believe the LEM can help to deepen the knowledge of these processes in other Andean basins exposed to these geomorphological processes.
Structural gender imbalances in ballet collaboration networks
(2023) Herrera-Guzmán, Yessica; Lee, Eun; Kim, Heetae
Ballet, a mainstream performing art predominantly associated with women, exhibits significant gender imbalances in leading positions. However, the collaboration’s structural composition vis-à-vis gender representation in the field remains unexplored. Our study investigates the gendered labor force composition and collaboration patterns in ballet creations. Our findings reveal gender disparities in ballet creations aligned with gendered collaboration patterns and women’s occupation of more peripheral network positions than men. Productivity disparities show women accessing 20–25% of ballet creations compared to men. Mathematically derived perception errors show the underestimation of women artists’ representation within ballet collaboration networks, potentially impacting women’s careers in the field. Our study highlights the structural imbalances that women face in ballet creations and emphasizes the need for a more inclusive and equal professional environment in the ballet industry. These insights contribute to a broader understanding of structural gender imbalances in artistic domains and can inform cultural organizations about potential affirmative actions toward a better representation of women leaders in ballet.
Linking physical violence to women’s mobility in Chile
(2023) Contreras, Hugo; Candia Vallejos, Cristian; Troncoso, Rodrigo; Ferres, Leo; Bravo, Loreto; Rodriguez-Sickert, Carlos
Despite increased global attention on violence against women, understanding the factors that lead to women becoming victims remains a critical challenge. Notably, the impact of domestic violence on women’s mobility—a critical determinant of their social and economic independence—has remained largely unexplored. This study bridges this gap, employing police records to quantify physical and psychological domestic violence, while leveraging mobile phone data to proxy women’s mobility. Our analyses reveal a negative correlation between physical violence and female mobility, an association that withstands robustness checks, including controls for economic independence variables like education, employment, and occupational segregation, bootstrapping of the data set, and applying a generalized propensity score matching identification strategy. The study emphasizes the potential causal role of physical violence on decreased female mobility, asserting the value of interdisciplinary research in exploring such multifaceted social phenomena to open avenues for preventive measures. The implications of this research extend into the realm of public policy and intervention development, offering new strategies to combat and ultimately eradicate domestic violence against women, thereby contributing to wider efforts toward gender equity.
Enhanced social connectivity in hybrid classrooms versus academic centrality in online settings
(2023) Pulgar, Javier; Ramírez, Diego; Candia Vallejos, Cristian
Social learning, the ability to perceive, interpret, and assess the behavior of one’s peers, is crucial for forming meaningful relationships and succeeding in various learning environments. Yet, the rise of online and hybrid settings poses new challenges to socialization. Here, we study the social interactions among 191 high school physics students in Chile, comparing online and hybrid classrooms that were assigned in the COVID-19 pandemic context. We found that students in hybrid settings were more connected and more likely to form casual relationships outside their immediate friend groups, which allowed them to gather new information from diverse sources. Along the same lines, in online classrooms, students who excelled in physics occupied more central positions in social networks. This trend was not evident in hybrid settings, suggesting that when social cues are limited, academic performance gains greater importance in establishing social hierarchies and potentially limiting access to diverse information. Our study highlights the importance of social interactions in educational contexts and raises questions about the impact of relational inaccessibility on virtual learning.
Relevance of machine learning techniques in water infrastructure integrity and quality : a review powered by natural language processing
(2023) García, José; Leiva-Araos, Andres; Diaz-Saavedra, Emerson; Moraga, Paola; Pinto, Hernan; Yepes. Víctor
Water infrastructure integrity, quality, and distribution are fundamental for public health, environmental sustainability, economic development, and climate change resilience. Ensuring the robustness and quality of water infrastructure is pivotal for sectors like agriculture, industry, and energy production. Machine learning (ML) offers potential for bolstering water infrastructure integrity and quality by analyzing extensive data from sensors and other sources, optimizing treatment protocols, minimizing water losses, and improving distribution methods. This study delves into ML applications in water infrastructure integrity and quality by analyzing English-language articles from 2015 onward, compiling a total of 1087 articles. Initially, a natural language processing approach centered on topic modeling was adopted to classify salient topics. From each identified topic, key terms were extracted and utilized in a semi-automatic selection process, pinpointing the most relevant articles for further scrutiny, while unsupervised ML algorithms can assist in extracting themes from the documents, generating meaningful topics often requires intricate hyperparameter adjustments. Leveraging the Bidirectional Encoder Representations from Transformers (BERTopic) enhanced the study’s contextual comprehension in topic modeling. This semi-automatic methodology for bibliographic exploration begins with a broad topic categorization, advancing to an exhaustive analysis of each topic. The insights drawn underscore ML’s instrumental role in enhancing water infrastructure’s integrity and quality, suggesting promising future research directions. Specifically, the study has identified four key areas where ML has been applied to water management: (1) advancements in the detection of water contaminants and soil erosion; (2) forecasting of water levels; (3) advanced techniques for leak detection in water networks; and (4) evaluation of water quality and potability. These findings underscore the transformative impact of ML on water infrastructure and suggest promising paths for continued investigation.
Pre-Andean deformation and its influence on the shortening of the Southern Precordillera, Mendoza, Argentina
(2023) Gutierrez Seia, Milagros; Jara, Pamela; Bertoa del Llano, Macarena; Richard, Andrés; Lothari, Lucas; Giambiagi, Laura Beatriz
Andean structures preserve evidence of previous periods of deformation along the proto-Pacific margin of Gondwana. Particularly, the Southern Precordillera, in the southern Central Andes, presents a combination of different structural domains and a double vergence related to the reactivation of pre-Andean structures. This combination and the superposition of deformational events make it difficult to understand the stratigraphic systems and the evolution of the region. This contribution presents detailed information about the structures and evolution of the Southern sector of the Precordillera, focusing on the control exerted by Paleozoic structures over the recent Andean deformation, and the deformational styles of this fold-and-thrust belt. Three main structural domains are recognized. The western domain is characterized by high-angle back-thrusts that concentrate the highest amount of uplift. The central domain is composed of reverse double-vergence faults, and high-angle strike-slip faults. The eastern domain is characterized by pure contractional deformation and only east-verging structures. Four deformational events are recorded and analyzed along the Southern Precordillera at 32°30′S: (1) an Early Paleozoic compressional event, (2) a Late Paleozoic compressional event, (3) a Triassic extensional event, and (4) the Cenozoic Andean compressional event. Our model for the Cenozoic deformation of the Southern Precordillera is restricted to three stages of deformation. During the first stage, Paleozoic west-verging faults are reactivated. The second stage implies reactivation of Paleozoic and Permian-Triassic structures and the generation of reverse Andean faults. The final stage consists of the generation of NE-SW Andean thrusts.
Oscillation results for a nonlinear fractional differential equation
(2023) Bosch, Paul; Rodríguez, José M.; Sigarreta, José M.
In this paper, the authors work with a general formulation of the fractional derivative of Caputo type. They study oscillatory solutions of differential equations involving these general fractional derivatives. In particular, they extend the Kamenev-type oscillation criterion given by Baleanu et al. in 2015. In addition, we prove results on the existence and uniqueness of solutions for many of the equations considered. Also, they complete their study with some examples.
A biomimetic smart kirigami soft metamaterial with multimodal remote locomotion mechanisms
(2023) Silva, Benjamín; Govan, Joseph; Zagal, Juan Cristóbal; Grossi, Bruno; Roldan, Alejandro; Nunez, Alvaro S.; Acuña, Daniel; Palza, Humberto
Several efforts have been made to develop walking smart soft robots through different strategies such as the use of complex aligned magneto-active materials. Here, we show a simple approach for the design of a smart soft robot using an elastomer film with randomly distributed ferrimagnetic nanoparticles able to be remotely controlled by a magnetic field. The magneto-active robot has a rotating-square kirigami geometry resulting in a flexible smart auxetic metamaterial (i.e., a negative Poisson-ratio structure). Alongside the standard translational locomotion on a smooth-surface under a steady magnetic force, the auxetic kirigami structure mimics the crawling-locomotion of worms over a high-roughness surface under an oscillatory horizontal field, even climbing vertical-obstacles. A theoretical understanding for this new locomotion mechanism stresses the relevance of the kirigami metamaterial design and the ferrimagnetic response of the particles. The soft robot can also transport a payload having weights higher than the weight of the smart elastomeric film. The smart auxetic structure further presents a rolling locomotion by properly orienting the magnetic field, meaning multiple remote locomotion mechanisms.
Optimizing the wine transportation process from bottling plants to ports
(2023) Basso, Franco; Contreras, Juan Pablo; Pezoa, Raúl; Troncozo, Alejandro; Varas, Mauricio
The wine industry is a highly competitive sector for which any efficiency improvement in the wine supply chain plays a critical role in maintaining or increasing profitability. Literature shows several successful applications of operational research tools at each stage of the wine production process. However, unlike other stages, the transportation and distribution phase has not been given the same attention in the specialized literature. To bridge this gap, this article proposes an integer linear programming model to jointly determine a plan for the bottling and transportation of products to ports in order to minimize inventory, freight, and delay costs. This model can be optimally solved in less than one day for small instances of up to 25 jobs. In practice, however, some industrial instances can easily exceed 200 jobs, which precludes the use of this model to support decision-making. To cope with this issue, we devise a two-stage procedure that generates good-quality solutions for industrial-size instances of this problem in reasonable computing times. Particularly, we show that the GAP of the proposed heuristic solution is relatively low for a wide range of instances. Finally, a case study is conducted on a medium-sized Chilean winery we worked with, where the planning generated by the proposed heuristic reduces the costs corresponding to the transportation stage by 45.3% in the best case, compared to the initial planning of the winery.
On the variable inverse sum deg index
(2023) Molina, Edil D.; Bosch, Paul; Sigarreta, José M.; Tourís , Eva
Several important topological indices studied in mathematical chemistry are expressed in the following way , where is a two variable function that satisfies the condition , denotes an edge of the graph and is the degree of the vertex . Among them, the variable inverse sum deg index , with , was found to have several applications. In this paper, we solve some problems posed by Vukičević [1], and we characterize graphs with maximum and minimum values of the index, for , in the following sets of graphs with vertices: graphs with fixed minimum degree, connected graphs with fixed minimum degree, graphs with fixed maximum degree, and connected graphs with fixed maximum degree. Also, we performed a QSPR analysis to test the predictive power of this index for some physicochemical properties of polyaromatic hydrocarbons.
On new Milne-type inequalities and applications
(2023) Bosch, Paul; Sigarreta, José M.; RODRIGUEZ GARCIA, JOSE MANUEL
Inequalities play a major role in pure and applied mathematics. In particular, the inequality plays an important role in the study of Rosseland’s integral for the stellar absorption. In this paper we obtain new Milne-type inequalities, and we apply them to the generalized Riemann–Liouville-type integral operators, which include most of the known Riemann–Liouville integral operators.
Necesidades arquitectónicas en viviendas de personas en situación de discapacidad
(2023) Valderrama-Ulloa, Claudia; Bucarey, Viviana; Marchetti Juan Pablo
Housing represents encounter, memories and security, but for people with disabilities some of its characteristics can become barriers to its full use. If disability is considered to be a poor relationship between environment and capacity. Housing may be inaccessible for this group of people. Based on the components of the International Classification of Functioning, Disability and Health, of the World Health Organization, and the application of 16 semi-structured interviews, this research analyzed the architectural barriers and identified the needs faced by people with Alzheimer, Parkison, blindness, children on the autism spectrum, the elderly, wheelchair users and people with deafness in relation to carrying out general tasks and demands, communication, mobility, self-care and domestic life inside the homes. Among the spaces with the greatest barriers are the bathroom and the kitchen for most of the cases analyzed. On the other hand, various strategies were observed that the interviewees use to cope with these barriers and increase their well-being or reduce the risks in the activities of daily living inside the dwellings.
Microbial community and enzyme activity of forest plantation, natural forests, and agricultural land in chilean coastal cordillera soils
(2023) Rivas, Yessica; Aponte, Humberto; Rivera-Salazar, Diego; Matus, Francisco; Martínez, Oscar; Encina, Carolina; Retamal-Salgado, Jorge
Despite the global expansion of forest plantations in Chile, their effect on biology properties of soil has still been only scarcely studied. Land use change in the Chilean Coastal Cordillera (36° to 40° S) is mainly attributed to the conversion of native forest to agriculture and forest plantations (Eucalyptus globulus and Pinus radiata de Don). The aim of this paper was to evaluate the changes in microbial composition (PCR-DGGE) and enzyme activity after the substitution of a native forest (e.g., Nothofagus spp.) by fast-growing exotic species and cropping. The most important factors that influence the abundance and diversity of bacteria and the fungi community were the soil organic matter (SOM) content, phosphorous (P-Olsen), calcium (Ca), boron (B), and water-holding capacity. These variables can better predict the microbial community composition and its enzymatic activity in the surface Ah horizon. Land use change also affected chemical soil properties of biogeochemical cycles. However, to deeply understand the connection between chemical and physical soil factors and microbial community composition, more research is needed. On the other hand, the expansion of forest plantations in Chile should be subject to legislation aimed to protect the biological legacy as a strategy for forest productivity as well as the soil microbial biodiversity.
Implementation of a course on disruptive technologies for nursing students in Chile
(2023) Contreras Romo, Jorge Sebastián; Cepeda Salas, Andrés Octavio
Several institutions and countries have recognized the need to integrate disruptive technologies in the training of health professionals. An elective course on disruptive technologies in health for nursing was developed, structured in 5 units: a) innovation in health and nursing, b) creation of apps and virtual environments, c) digital manufacturing for nursing, d) sensors and internet of things, and e) data science in health. For its implementation, the didactic model proposed by Jorba and Sanmartí was considered; and for the evaluation of the units and the impact of the course, Urquidi's extended model of technological adoption was used. Forty-four students participated (39 women and 5 men), with an average age of 23 years. According to the technology acceptance model, statistically significant differences were found between the pre- and post-intervention groups in all dimensions of the model (Wilcoxon test, p < 0.05). In addition, a positive correlation was found between ease of use, subjective norm and intention to use the technologies taught. The implementation of the disruptive technologies course proved to be effective in the development of technological skills among nursing students in Chile.
Generation of soil maps permeability. Case study in two cantons of Loja province, Ecuador
(2023) Espinosa Marín, Jorge Andrés; Rivera, Diego; Haro Prado, Renato
The generation of permeability maps is based on the analysis and interpretation of geology, environmental morphology, land use, and slope, which enables the selection of sampling areas with similar characteristics. The method represents the integration of the physical characteristics of the study area and then determines the infiltration capacity differences in the most representative geopedologic units. In determining the basic data, minidisc infiltrometers were used to perform seventy-two infiltration tests in different types of soils with varying organic matter content, texture, soil structure, and vegetation cover, which showed the spatial variability that exists in two cantons of Loja province, Ecuador. In addition, it was observed that the infiltration rate depended mainly on the content of the organic matter in the soil and is consistent with information collected on permeability worldwide. In this study, generated pedotransfer function (FTP) coefficient of determination R. 0.78, the determination of the coefficient indicates a satisfactory estimate of the permeability with the variables that were analyzed; in addition, the methodology for assessing the permeability was suitable for the conditions of this investigation. For this reason, the method described here should be tested in other areas of the country with a greater number of field trials and with more variable contents of organic matter and soil textural classes.
From co-location patterns to an informal social network of gig economy workers
(2023) Pilatti, Gustavo; Candia, Cristian; Montini, Alessandra; Pinheiro, Flávio L.
The labor market has transformed with the advent of the gig economy, characterized by short-term and flexible work arrangements facilitated by online platforms. As this trend becomes increasingly prevalent, it presents unique opportunities and challenges. In this manuscript, we comprehensively characterize the social networks of gig economy workers in each of the 15 cities studied. Our analysis reveals a scaling relationship between networks and the city population. In particular, we note the high level of modularity of the networks, and we argue that it results from the natural specialization of couriers along different areas of the cities. Furthermore, we show that degree and betweenness centrality is positively correlated with income but not with tenure. Our findings shed new light on the social organization of the gig economy workers and provide valuable insights for the management and design of gig economy platforms.

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