Artículos de conferencia

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A method to determine container seaport hinterlands
(2018) Mac Cawley Vergara, Alejandro Francisco; Vega, Javier N.; Florez Calderón, Luz Angela; Giesen Encina, Ricardo
This paper proposes a model to delimit the hinterlands for South America's main ports, considering Euclidean distances and the actual routes existing in the region. The differences between these two methods were analyzed and the impact of the main costs variables was quantified on the port hinterland. This is a new approach to hinterland modelling, since it considers the actual routes used to transport goods in the region. We assume that port selection is mainly based on the objective of minimizing the total cost of intermodal freight transport. The proposed methodology can be used to determine the ports captive hinterlands and analyze which variables affect the size and the shape of these hinterlands. We apply the methodology to six ports in South America and four destinations. Results show that the differences between the hinterlands modelled by the two methods are considerable, reaching 280 billion dollars in GDP captured for some ports. © ILS 2018 - Information Systems, Logistics and Supply Chain, Proceedings.
A multi-channel speech enhancement method based on subband affine projection algorithm in combination with proposed circular nested microphone array
(2021) Firoozabadi, A. D.; Irarrázaval Mena, Pablo; Adasme, P.; Durney, H.; Olave, M. S.; Zabala Blanco, D.; Azurdia Meza, C.
A Novel Quasi-Spherical Nested Microphone Array and Multiresolution Modified SRP by GammaTone Filterbank for Multiple Speakers Localization
(2019) Firoozabadi, A.D.; Irarrazaval Mena, Pablo; Adasme P.; Durney, H.; Olave, M.S
Algebraic Reconstruction of Source and Attenuation in SPECT Using First Scattering Measurements
(Springer, 2018) Cueva, Evelyn; Osses Alvarado, Axel Esteban; Quintana Fresno, Juan Carlos; Tejos Núñez, Cristián Andrés; Courdurier Bettancourt Matias Alejandro; Irarrazaval Mena, Pablo
Here we present an Algebraic Reconstruction Technique (ART) for solving the identification problem in Single Photon Emission Computed Tomography (SPECT). Traditional reconstruction for SPECT is done by finding the radiation source, nevertheless the attenuation of the surrounding tissue affects the data. In this context, ballistic and first scattering information are used to recover source and attenuation simultaneously. Both measurements are related with the Attenuated Radon Transform and a Klein-Nishina angular type dependency is considered for the scattering. The proposed ART algorithm allow us to obtain good reconstructions of both objects in a few number of iterations.
Boosting SpLSA for Text Classification
(2017) Hurtado, Julio; Mendoza, Marcelo; Nanculef, Ricardo
Text classification is a challenge in document labeling tasks such as spam filtering and sentiment analysis. Due to the descriptive richness of generative approaches such as probabilistic Latent Semantic Analysis (pLSA), documents are often modeled using these kind of strategies. Recently, a supervised extension of pLSA (spLSA [10]) has been proposed for human action recognition in the context of computer vision. In this paper we propose to extend spLSA to be used in text classification. We do this by introducing two extensions in spLSA: (a) Regularized spLSA, and (b) Label uncertainty in spLSA. We evaluate the proposal in spam filtering and sentiment analysis classification tasks. Experimental results show that spLSA outperforms pLSA in both tasks. In addition, our extensions favor fast convergence suggesting that the use of spLSA may reduce training time while achieving the same accuracy as more expensive methods such as sLDA or SVM.
Building a geographic data repository for urban research with free software - Learning from Observatorio.Cedeus.cl
(2017) Steiniger, Stefan; De La Fuente, H.; Fuentes, C.; Barton Jonathan Richard; Muñoz Abogabir, Juan Carlos; CEDEUS (Chile)
The recent trend towards open data and open science as well as a demand for holistic and interdisciplinary research requires platforms that allow the distribution and exchange of research data, including geographic information. While the requirements and benefits of data exchange are widely discussed, there are few proposals on how to implement data platforms that not only permit the exchange of research data among researchers, but also permit to distribute research results and data to the interest public. We elaborate what points are important for implementing a (geographic) data repository and propose then to adopt the concept of Spatial Data Infrastructures (SDI) as a solution for the implementation of research data repositories. We present as a case study the geographic data and document repository of the Chilean research Centre on Sustainable Urban Development (CEDEUS), the CEDEUS Observatory. Besides the infrastructure to host and distribute data, communication tools are an important component of such a data repository service. For this case study we analyse which things have worked well and which things have not worked well based on the experiences collected during three years of operation. We close with some recommendations for the implementation of data repositories for research.
Can Cushioned Shoes with Anatomical Insole Correct theImpact in Runners with Recurring Shin Splint?
(2015) De La Fuente Cancino Carlos Ignacio; Henríquez, Ramírez, Hugo; Ramírez-Campillo, Rodrigo; Delgado Bravo Mauricio Antonio; Chamorro Lange, Claudio Hernán; Ruidiaz, Sebastián; Campos Jara, Christian Alex; Carcuro, Giovanni
Clinical processes and its data, what can we do with them?
(2015) Rojas, Eric; Arias, Michael; Sepúlveda Fernández, Marcos Ernesto
Global healthcare services have evolved over time, and nowadays they are expected to follow high-quality optimized standards. Analyzing healthcare processes has become a relevant field of study, and different techniques and tools have been developed to promote improvements in the efficiency and effectiveness of these processes. There is a research field called process mining that can be used to extract knowledge from the event data stored in the hospital information systems. With the help of this, it is possible to discover the real executed process, examine its performance and analyze the resource interaction during its execution. The goal of this article is to provide a bibliographic survey about the use of process mining algorithms, techniques, and tools in the analysis of healthcare processes, providing a general overview about the main approaches previously used and the information required to apply them in the medical field. We provide important insights about data, algorithms, techniques and methodologies that are required to help answer medical expert questions about their processes, motivating and inspiring a broader usage. So, if we have the information and it is possible to analyze and understand the healthcare processes, why are we not doing it?
Determination of modal properties and FE model updating of the Metropolitan Cathedral of Santiago de Chile
(2016) Torres, W.; Almazán Campillay, José Luis; Sandoval Mandujano, Cristián; Boroschek, R.
Examining the role of urban form in supporting rapid and safe tsunami evacuations: A multi-scalar analysis in Viña del Mar, Chile
(2018) León, Jorge; Mokrani, Cyril; Catalán, Patricio; Cienfuegos Carrasco, Rodrigo Alberto; Femenías, Carolina
Cities are increasingly becoming hot-spots for nature-originated disasters. While the role of the urban built environment in fostering disaster resilience has been recognized for some time, it has been difficult to translate this potential into practice. This is especially challenging in the case of rapid onset crises such as near-field tsunamis, when appropriate urban forms have to support the populations' ability to autonomously carry out safe and timely responses. In this respect, much of current research remains focused on large-scale elements of urban configuration (streets, squares, parks, etc.) through which people move during an emergency. In contrast, the critical micro-scale of evacuees' experiences within the built environment is not commonly examined. This paper addresses this shortfall through a macro- and micro-scale analysis of a near-field tsunami scenario affecting the city of Villa del Mar, Chile, including a mixed-methods approach that combines computer-based models and fieldwork. The results show significant macro-scale tsunami vulnerability throughout major areas of the city, which nonetheless could be mitigated by existing nearby high ground and an urban form that allows short evacuation times. However, micro-scale outcomes show comparatively deficient spatial conditions that during an emergency might lead to dangerous outcomes including bottlenecks, falls and panic. Vertical evacuation, in turn, is confirmed as a suitable option for reducing vulnerability, but further examination of each shelter's characteristics is required. (C) 2018 The Authors. Published by Elsevier Ltd.
HIV infection of astrocytes increases release of Dickkopf-1 protein by a gap junction and hemichannel dependent mechanism
(Springer, 2012) Orellana Roca, Juan Andrés; Sáez, Juan Carlos; Berman, Joan; Eugenín Arce, Eliseo Alberto
Human immunodeficiency virus-1 (HIV) is a major public health issue, with a significant CNS complication of infection, NeuroAIDS. In vivo, microglia/macrophages are the main cells infected. However, a low but significant number of HIV infected astrocytes also has been detected, but their role in the pathogenesis of NeuroAIDS is not well understood. Our previous data indicated that HIV infection of astrocytes increased expression of the glycoprotein, dickkopf-1 protein (Dkk1), a soluble inhibitor of the wnt pathway. In HIV infected cultures of human astrocytes, secretion of Dkk1 was highly regulated by functional gap junction channels and connexin43 hemichannels. We also demonstrated that Dkk1 expression in astrocytes was increased in human brain tissue sections of individuals with HIV encephalitis as compared to tissue sections from uninfected individuals. We demonstrated that in primary cells, Dkk1 secretion did not participate in bystander killing of uninfected astrocytes or viral reactivation. However, its secretion regulates neuronal damage measured by collapse of neuronal processes. Thus, we demonstrated that HIV infection of astrocytes dysregulates secretion of Dkk1 by a mechanisms that involves both gap junctions as well as hemichannels that contributes to the neuropathogenesis observed in HIV infected individuals.
Identifying critical components in power distribution networks using graph theoretical measures
(2019) Llera Martin, Juan Carlos de la; Monsalve, Mauricio
Critical infrastructures (CIs) are spatially distributed infrastructure networks that supply essential services and goods to our society. However, CIs are exposed to diverse disruptive and severe natural events, random failures and manmade attacks, which undermine their proper functioning producing negative impacts on the population. In this context, it is of paramount importance to identify which are the most relevant CI components that deserve special attention for improving CIs protection. The identification of critical components is a well consolidated practice in risk analysis of complex technological systems; however, when looking at real-world spatially-distributed CIs, identifying the most critical components precisely is challenging. Indeed, CIs cover large spatial areas, have variable degrees of redundancy, and often exhibit irregular topological characteristics. In order to address this problem, this work looks at the ability of different graph theoretical measures or scores at identifying critical components in power distribution networks to later compare them. The scores considered herein include various network centrality measures (degree, eigenvector, closeness, betweenness) and some variations. The comparison of these measures is performed on three power distribution networks from central Chile, finding that a variant of betweenness centrality is the best at identifying the most critical components.
Impact of earthquake magnitude on the estimation of tsunami evacuation casualties
(2018) Castro, S.; Poulos, A.; Urrutia, A.; Herrera, J. C.; Cienfuegos, R.; Llera Martin, Juan Carlos de la
The importance of evacuation plans has been widely proven in recent tsunami events. Several evacuation models have been proposed to develop these plans and estimate city evacuation times. Typically, single extreme earthquake scenarios are used in these estimations; however, the impact of earthquake damage on the evacuation routes is usually neglected in these models. This article deals with the evaluation of the effect of three different earthquake magnitudes and the following tsunamis. Several spectral accelerations were sampled for each magnitude to estimate city damage, and from there the reduced capacity of evacuation routes due to earthquake debris. An agent-based evacuation model was used to assess the evacuation times for the city of Iquique, located in north Chile. Results show significant variability for different magnitude scenarios, thus leading to an observed increment on evacuation times up to 40% and an increase in the number of casualties due to the evacuation delay caused by earthquake debris spread on the evacuation routes
Managing Strategic Participation Through Design Principles : A Model for Value Co-Creation in Service-Based Organizations
(2021) Salvatierra Rondón, Rocío del Pilar
Neruda in construction: An analysis of his Chilean houses
(2015) De Holanda, Frederico; De França, Franciney Carreiro; Greene Zuniga Margarita
Isla Negra, Michoacán, La Chascona and La Sebastiana are the names that the Chilean Nobel lauret poet, Pablo Neruda, used to refer to his houses. Neruda build his houses, he named them and wrote poetry to them. The names, as the houses, are full of charm and mystery and seem to evoke many things: a territory, a location or a tribute to a woman. The proposition in this paper is that through their construction Neruda offered us not only a rich collection of original and somewhat eclectic edifices and an insight to his rich life, but also a set of buildings that were carefully thought and built in search of a perfect combination of 'creative individual' and 'collective social' space. This was done through multiple interventions to his houses that can be best understood through a configurational analysis of the different construction stages. The many studies carried out on Pablo Neruda's houses, have privileged the analysis and description of each space as separate entities, their particular history, their individual meaning, not aiming at a global spatial perspective and the configurational aspects have not been explored. By contrast, this paper is based in the historiography of Pablo Neruda's houses, and how he planned and built their expansion. A study of their spatial configuration is put forward. It aims at unveiling the deeper significance of each house from a systemic perspective, and even more of the set of houses understood as a particular Nerudian way of living in space. Although different in terms of volume and form, the houses express a rich spatial language of its own creator. Neruda was not only the owner or occupant, but interfered directly in the design of these spaces. The result is a set of homes that are able to enchant by their idiosyncrasies, by the mix of materials, and especially due to their spatial connections. The paper is part of a post-doctorate research in progress, using the space syntax theory and methodology. The theory is able to reveal a spatial language; the space convex methodology was used and the graphs of permeability, depth and integration measure revealed how the houses have become the Nerudian space. The approach was essential to: i) study each house and its particular process of expansion or alteration; ii) analyze them as a set, comparing the final version of each house with one another. The result is a spatial concept with a clear intention of establishing multiple connections from the outside, creating a shallower structure in Isla Negra and Michoacán or a deeper structure in La Se-bastiana and La Chascona. In all of them, Neruda's private workspace, the space of his creation, can be described as a segregated and isolated tower, while the collective social area occupied shallow spaces, often connected to the exterior. In fact, not surprisingly, Neruda challenged social conventions in his distribution of the private and public functions.
PALIA-ER: Bringing question-driven process mining closer to the emergency room
(2017) Rojas, Eric; Fernández-Llatas, Carlos; Traver, Vicente; Muñoz-Gama, Vicente; Sepúlveda, Marcos; Herskovic, Valeria; Capurro, Daniel
This paper presents PALIA-ER, a web-based tool for question-driven process mining in Emergency Room. PALIA-ER uses Palia discovery algorithm and includes model simplification and filtering features specially domain-specific for ER. Most PALIA-ER functionalities can be easily applied to other interdisciplinary contexts such as other healthcare units, education, or logistics.
PEERING THROUGH THE DUST: PRECISE ASTROMETRY IN THE GALACTIC MID-PLANE WITH THE VVV SURVEY
(2015) Lucas, PW; Smart, RL; Jones, HRA; Kurtev, R; Beamin Muhlenbrock, Juan Carlos; Borissova, J.; Gromadzki, Grzegorz; Ivanov, Valentin; Minniti, Dante; Pinfield, DJ
Gaia will see little of the Galactic mid-plane and nuclear bulge due to high extinction at optical wavelengths. To study the structure and kinematics of the inner Galaxy we must look to longer wavelengths. The Vista Variables in the Via Lactea (VVV, Minniti et al. 2010) survey currently provides just over 4 years of observations covering approximately 560 square degrees of the Galactic bulge and plane. Typically each source is observed 50-150 times in the Ks band over this period. Using these data we provide relative proper motions for approximately 200 million unique sources down to Ks similar to 16 with uncertainties approaching 1 mas yr(-1). In addition, we fit a solution of the parallactic motion of all sources with significant proper motion and discover a number of new nearby brown dwarfs. These results will allow us to identify faint common proper motion companions to stars with Gaia parallaxes, increasing the number of brown dwarf benchmark objects. Our absolute astrometric calibration precision is currently similar to 2 mas yr(-1), based on PPMXL. The Gaia absolute astrometric reference grid will allow us to precisely anchor our results and measure the streaming motions of stars in the bulge. Finally, we anticipate that the catalogue could provide kinematic distances to the numerous optically invisible high amplitude variable stars that VVV is discovering.
Process Remaining Time Prediction using Query Catalogs
(2014) Sepúlveda Fernández, Marcos Ernesto; Bolt Iriondo, Alfredo José
Psychosocial stress affects attentional control and neural oscillatory activity
(2015) Palacios García, Ismael; Villena González, Mario; Campos Arteaga, German; Artigas Vergara, Claudio; Jaramillo, Karina; Silva, Jaime; Rodríguez, Eugenio
Every day we have to divide our limited attentional resources into different external and internal demands. Considering that psychosocial stress promotes the allocation of attentional resources to threat-related stimuli such as the social evaluation, the aim of the study is (1) to investigate if psychosocial stress affects the behavioral performance in an attentional shifting task and (2) to search, under an exploratory approach, some of its neural correlates. 40 healthy participants were exposed to either an electroencephalogram-compatible version of the Trier Social Stress Test (TSST) or a control protocol. Additionally, immediately before and after these protocols, subject participated in the attentional shifting task. Manipulation checks were verified through the changes of the heart rate, salivary concentration of cortisol and the score in the anxiety scale in the “stress” condition respect the control. When we compared the behavioral performance in the attentional task prior and after both conditions, we found that the control group showed a clear improvement in performance, characterized by a relative increase of correct trials and a decrease of omissions. Analogously, after the TSST, participants showed a decreases of the correct trials and an increase of omissions. In addition to behavioral results, we found that the oscillatory activity in alpha (8–12 Hz) and gamma bands (30–70 Hz) were different in both conditions. Behavioral and electrophysiological results, suggest that psychosocial stress directs the attention internally, limiting the attentional resources for attending the external demands and inducing cognitive failures.
Representation and modeling of the Chilean electric power network for seismic resilience analysis
(2020) Ferrario E.; Poulos A.; Llera Martin, Juan Carlos de la; Lorca A.; Oneto A.; Magnere C.
Electric Power Networks (EPNs) are exposed to the occurrence of highly disruptive natural events such as large earthquakes. The physical damage to EPN components due to seismic events can seriously compromise the ability to generate, transmit, and distribute electricity to final users and to other interconnected critical infrastructures. In this context, resilience analysis is fundamental to identify the key components at risk to sustain or quickly restore the EPN functionality. This work presents a first step in the development of a detailed Chilean EPN model and illustrates an analysis framework to assess its resilience under the occurrence of earthquake scenarios. Specifically, the Chilean EPN model is built at a high level of detail using several Chilean data sources. Then, resilience of the network is assessed in four main steps: (1) generation of local intensity levels at the component sites; (2) evaluation of the earthquake impact on the EPN components using their fragilities; (3) evaluation of the component recovery time using downtime distributions; and (4) estimation of the EPN performance by means of simulating an optimal power flow model throughout the restoration process until service is fully restored. Results are expected to contribute toward a more resilient Chilean power network under seismic action.

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