University of Atacama or UDA is a university in Chile. It is part of the Chilean Traditional Universities. The university is located in Copiapó, in the Third Region, Atacama.The University was created in 1981, as a fusion of the old Mines School of Copiapo, founded in 1857 and very prestigious in the minerals industries, this School was integrated in 1947 in early foundated Universidad Técnica del Estado, being the new U.T.E. until 1981 the most important Chilean university in applied science and the Normal School of Copiapó, founded in 1905. UDA has four Faculties: Humanities and Education, Law, Engineering, and Natural science, as well as five institutes: the Technological Institute, the Language Institute, the Center for Technical Education , the Institute for Scientific and Technological Research , and INSAMIN.The University of Atacama houses several historical monuments on campus, including the first steam engine to traverse Chile, between Copiapó and the port city of Caldera, in 1851. Wikipedia.
Carrizo D.,University of Atacama
Proceedings - 2016 10th International Conference on the Quality of Information and Communications Technology, QUATIC 2016 | Year: 2016
In terms of capturing software requirements, the most appropriate elicitation technique must be selected, but what does this mean? This paper makes a comparison between what researchers and software engineers see as adequate technique for capturing relevant information to meet software requirements. A systematic mapping of constructs which researchers define as good techniques is presented and compared with practitioners' opinions. The study identified 13 constructs that were finally whittled down to six. The software engineers' survey showed no significant difference between these constructs. This work demonstrates the divergence of views between researchers and practitioners about the quality of software requirement elicitation techniques. The results call for more empirical research to define a common way to measure the performance of techniques and so to support their selection. © 2016 IEEE.
Dib S.,Copenhagen University |
Dib S.,University of Atacama |
Schmeja S.,University of Heidelberg |
Hony S.,University of Heidelberg
Monthly Notices of the Royal Astronomical Society | Year: 2017
We investigate whether the stellar initial mass function (IMF) is universal, or whether it varies significantly among young stellar clusters in the MilkyWay.We propose a method to uncover the range of variation of the parameters that describe the shape of the IMF for the population of young Galactic clusters.These parameters are the slopes in the low and high stellar mass regimes, γ and Γ, respectively, and the characteristic mass, Mch. The method relies exclusively on the high-mass content of the clusters, but is able to yield information on the distributions of parameters that describe the IMF over the entire stellar mass range. This is achieved by comparing the fractions of single and lonely massive O stars in a recent catalogue of the Milky Way clusters with a library of simulated clusters built with various distribution functions of the IMF parameters. The synthetic clusters are corrected for the effects of the binary population, stellar evolution, sample incompleteness, and ejected O stars. Our findings indicate that broad distributions of the IMF parameters are required in order to reproduce the fractions of single and lonely O stars in Galactic clusters. They also do not lend support to the existence of a cluster mass-maximum stellar mass relation. We propose a probabilistic formulation of the IMF whereby the parameters of the IMF are described by Gaussian distribution functions centred around γ = 0.91, Γ = 1.37, and Mch = 0.41 M⊙, and with dispersions of σγ = 0.25, σΓ = 0.60, and σMch = 0.27 M⊙ around these values. © 2016 The Authors.
Shadmehri M.,Golestan University |
Khajenabi F.,Golestan University |
Dib S.,Copenhagen University |
Dib S.,University of Atacama
Monthly Notices of the Royal Astronomical Society | Year: 2017
Self-gravitating accretion discs in a gravitoturbulent state, including radiation and gas pressures, are studied using a set of new analytical solutions. While the Toomre parameter of the disc remains close to its critical value for the onset of gravitational instability, the dimensionless stress parameter is uniquely determined from the thermal energy reservoir of the disc and its cooling rate. Our solutions are applicable to the accretion discs with dynamically important radiation pressure such as that in the quasars discs. We show that physical quantities of a gravitoturbulent disc in the presence of radiation are significantly modified compared to solutions with only gas pressure.We show that the dimensionless stress parameter is an increasing function of the radial distance so that its steepness strongly depends on the accretion rate. In a disc without radiation its slope is 4.5; however, we show that in the presence of radiation, it varies between 2 and 4.5 depending on the accretion rate and the central mass. As for the surface density, we find a shallower profile with an exponent -2 in a disc with sub-Eddington accretion rate compared to a similar disc, but without radiation, where its surface density slope is -3 independent of the accretion rate. We then investigate gravitational stability of the disc when the stress parameter reaches to its critical value. In order to self-consistently determine the fragmentation boundary, however, it is shown that the critical value of the stress parameter is a power-law function of the ratio of gas pressure and the total pressure and its exponent is around 1.7.We also estimate the maximum mass of the central black hole using our analytical solutions. © 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.
Mery D.,University of Chile |
Mondragon G.,University of Chile |
Riffo V.,University of Chile |
Zuccar I.,University of Atacama
Insight: Non-Destructive Testing and Condition Monitoring | Year: 2013
In order to reduce the security risk of a commercial aircraft, passengers are not allowed to take certain items in carry-on baggage. For this reason, human operators are trained to detect prohibited items using a manually controlled baggage screening process. In this paper, we propose the use of a method based on multiple X-ray views to detect some regular prohibited items with very defined shapes and sizes. The method consists of two steps: 'structure estimation', to obtain a geometric model of the multiple views from the object to be inspected (baggage); and 'parts detection', to detect the parts of interest (prohibited items). The geometric model is estimated using a structure from a motion algorithm. The detection of the parts of interest is performed by an ad-hoc segmentation algorithm (object dependent) followed by a general tracking algorithm based on geometric and appearance constraints. In order to illustrate the effectiveness of the proposed method, experimental results on detecting regular objects - razor blades and guns - are shown yielding promising results. © 2013 Publishing Technology.
News Article | November 3, 2015
Looking at pictures of Chile's Atacama Desert right now, you would never know it's one of the driest places on the planet. Normally the landscape is parched and arid. But this year it's covered in flowers—mauves, reds, yellows, whites—creating a stunning and unusual spectacle. Heavy rains prepared the ground back in March. The Atacama region saw almost an inch of rain in one day—the equivalent of 14 years of rain in 24 hours. "This year has been particularly special, because the amount of rainfall has made this perhaps the most spectacular of the past 40 or 50 years," Raul Cespedes, a desert scientist at the University of Atacama, told AFP. According to AFP, the flowers include violet-and-white Chilean bell flowers, countryside sighs (Nolana paradoxa), red lion claws (Bomarea ovallei), and yellow Rhodophiala rhodolirion. Because of the intensity of the storms, there were two flowerings: in the winter and now again in the Chilean spring. "Two flowerings a year is very unusual in the most arid desert in the world, and that's something we've been able to enjoy this spring, along with people from all over the world. There's a lot of interest in seeing it," Daniel Diaz, director of the National Tourism Service in Atacama, told AFP. Meteorologists blame El Niño for the extreme rainfall in Atacama and warn of worse to come as that weather pattern intensifies. But for now, the event is a boon for tourism and a something to marvel at: flowers where flowers don't normally grow.
Santander M.,Federal University of Rio Grande do Sul |
Santander M.,University of Atacama |
Rodrigues R.T.,Federal University of Rio Grande do Sul |
Rubio J.,Federal University of Rio Grande do Sul
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2011
This work presents results of a rapid emulsified oil (petroleum) removal from water by flocculation followed by flotation in a modified jet (Jameson) cell (MJC). The modification is such that the downcomer was sealed at the bottom (by a concentric blind-end tube) to allow floated particles to enter immediately into the frothy phase after the capture of the oily flocs by the bubbles. Also, a packed bed (crowder) was placed at the upper part of the concentric tube to stabilize the froth and facilitate the rise of the oil floc/bubble aggregates. The work was divided into two parts: a detailed laboratory study (1.3m3/h) and a pilot plant trial in an offshore platform. Parameters studied were flocculation (type and concentration of polymer), oil concentration, oil droplets size distribution and flotation cell design. Results of laboratory studies showed mean separation efficiencies of the order of 80% when used as a conventional jet cell (CJC) with feed emulsions (droplets size of about 20μm) ranged between 100 and 400mg/L petroleum concentration. The oil removal increased up to 85% in the MJC. These studies allowed optimizing the design and process parameters: chemical, physico-chemical and operating. A MJC (5m3/h) was then projected, built and installed in an offshore platform, after the oil extraction-production point. At optimal conditions, in a single flotation stage, discharges varied between 20 and 30mg/L oil concentration or 81% removal at 24.7m3/hm2 loading capacity. Because this jet cell operates with a high air hold-up, it presented a very good efficiency (capture of oil droplets by bubbles) at low residence time (high-rate separation) and showed to be simple, compact and easy to operate. It is believed that the MJC has a great potential for treating polluted oily high flow wastewaters, at high separation rate. Results and mechanisms involved are discussed in terms of interfacial phenomena and design factors. © 2011 Elsevier B.V.
Palacios J.,University of Atacama |
Sanchez M.,University of Concepción
Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy | Year: 2011
Copper production from sulphide minerals generates massive amounts of slag as final waste of the pyrometallurgical processes. Dumping the slag nearby the smelter plant has been the common practice and, currently it is produced in a proportion of 2.2 ton of slag per ton of blister copper and is granulated to facilitate the transportation and final disposal. Thus, it is relevant to improve sustainability by recycling this waste to minimise the environmental impact generated during pyrometallurgical treatment of copper sulphides concentrates. Laboratory tests were run in order to concentrate and separate metals and materials for obtaining results that could be scaled up to pilot and industrial level. The results of pyrometallurgical and hydrometallurgical experiments are presented in order to show the importance of the oxidation of the slag at high temperatures that could liberate those metals molecularly entrapped during processing sulphide concentrate in the smelter plant. Therefore, the present work shows experimental work done in Chile in order to add value to this waste by recovering contained metals and materials such as copper, molybdenum, and iron and silica, with iron and silica being more than half of the total content of the slag, which has an important effect on the volume of the stocked material. © 2011 Institute of Materials, Minerals and Mining and The AusIMM.
Rivera J.D.D.,University of Atacama
Atmospheric Research | Year: 2011
Fog water collectors (FWC) can provide water to arid zones with persistent advection and orographic fog. A key feature of any FWC is the mesh used to capture fog droplets. Two relevant mesh characteristics are its shade coefficient and the characteristics of the fibers used to weave or knit the mesh. This paper develops a simple superposition model to analyze the effect of these factors on the Aerodynamic Collection Efficiency (ACE) of FWCs. Due to the simplicity of the model it cannot be directly applied to actual FWC meshes, and serve only for guidance on the order of magnitude of the optimum shade coefficient and the corresponding ACE. The model shows that there is a maximum ACE of the order of 20-24.5% for shade coefficients between 0.5 and 0.6, for the particular mesh simulated. Aerodynamic collection efficiency can be increased by making the FWC concave and improving the aerodynamics of the mesh fibers. © 2011 Elsevier B.V.
Thomas J.C.R.,University of Atacama
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
This project shows the development of a new clustering algorithm, based on k-means, which faces its problems with clusters of differences variances. This new algorithm uses a line segment as prototype which captures the axis that presents the biggest variance of the cluster. The line segment adjusts iteratively its long and direction as the data are classified. To perform the classification, a border region that determines approximately the limit on the cluster is built based on geometric model, which depends on the central line segment. The data are classified later according to their proximity to the different border regions. The process is repeated until the parameters of the all border regions associated with each cluster remain constant. © 2011 Springer-Verlag.
Influential contextual attributes in the requirements elicitation process: A comprehensive literature review [Atributos contextuales influyentes en el proceso de educción de requisitos: Una exhaustiva revisión de literatura]
Moreno D.C.,University of Atacama
Ingeniare | Year: 2015
The requirements elicitation captures relevant information to the shaping of software requirements by using several techniques. However, the effectiveness of the process depends on the context in which it occurs. This article aims to reveal the attributes of the context influencing the elicitation process. For this purpose, a systematic and non-systematic review of the scientific literature was conducted in order to determine which are these attributes. The result of this review yielded 118 attributes that were grouped into 27 generic attributes corresponding to 5 factors: the eductor, the informant, the problem domain, the solution domain and the process itself. This study helps to guide future empirical researches on requirements elicitation pointing out possible experimental factors to consider. © 2015, Universidad de Tarapaca. All rights reserved.