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Ítem Tuning of Adaptive Weight Depth Map Generation Algorithms Exploratory Data Analysis and Design of Computer Experiments DOCE(SPRINGER, 2012-07-01) Acosta, Diego Andrés; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosÍtem Collaborative Networked Virtual Surgical Simulators (CNVSS): Factors Affecting Collaborative Performance(MIT PRESS, 2013-01-01) Diaz, Christian; Trefftz, Helmuth; Quintero, Lucia; Acosta, Diego A.; Srivastava, Sakti; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosStand-alone and networked surgical simulators based on virtual reality have been proposed as a means to train surgeons in specific surgical skills with or without expert guidance and supervision. However, a surgical operation usually involves a group of medical practitioners who cooperate as team members. To this end, CNVSS have been proposed for the collaborative training of surgical procedures in which users with different surgical roles can take part in the training session. To be successful, these simulators should guarantee synchronicity, which requires (1) consistent viewing of the surgical scene and (2) a quick response time. These two variables are affected by factors such as users' machine capabilities and network conditions. As far as we know, the impact of these factors on the performance of CNVSS has not been evaluated. In this paper, we describe the development of CNVSS and a statistical factorial design of experiments (DOE) to determine the most important factors affecting collaboration in CNVSS. From the results obtained, it was concluded that delay, jitter, packet loss percentage, and processor speed have a major impact on collaboration in CNVSS.Ítem Diseño conceptual de una sonda langmüir para caracterización de plasmas fríos mediante diseño estadístico de experimentos.(IMPRENTA UNIV ANTIOQUIA, 2013-01-01) Camargo, V.; Acosta, Diego A.; JARAMILLO, JUAN MANUEL; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe characterization and control of plasma-assisted processes, has become increasingly urgent to adapt this kind technology to industrial contexts. This work presents the design and construction of a cold plasma characterization system by electrostatic means (Langmuir probe), based on concepts of plasma physics and tools of engineering, design of experiments and conceptual design. The result of this work is a functional prototype probe and some measurements on the reactor.Ítem Fitting of Analytic Surfaces to Noisy Point Clouds(2013-01-01) RUIZ, OSCAR EDUARDO; Arroyave-Tobón, S.; Acosta, Diego A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosFitting -continuous or superior surfaces to a set of points sampled on a 2-manifold is central to reverse engineering, computer aided geometric modeling, entertaining, modeling of art heritage, etc. This article addresses the fitting of analytic (ellipsoÍtem Conceptual design of a Langmuir probe for cold plasma characterization employing statistical design of experiments(IMPRENTA UNIV ANTIOQUIA, 2013-06-01) Camargo Suarez, Victor Hugo; Acosta Maya, Diego Andres; Jaramillo O, Juan Manuel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe characterization and control of plasma-assisted processes, has become increasingly urgent to adapt this kind technology to industrial contexts. This work presents the design and construction of a cold plasma characterization system by electrostatic means (Langmuir probe), based on concepts of plasma physics and tools of engineering, design of experiments and conceptual design. The result of this work is a functional prototype probe and some measurements on the reactor.Ítem Design of computer experiments applied to modeling of compliant mechanisms for real-time control(SPRINGER, 2013-07-01) Acosta, Diego A.; Restrepo, David; Durango, Sebastian; Ruiz, Oscar E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThis article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force-displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyzing the input-output data of a DOCE) of compliant mechanisms (CMs). The procedure discussed produces a force-displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time. In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA). The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions. The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, ? x, ? y, ? z ) of its moving platform. In the multi-linear model fit of the HexFlex, the products or interactions proved to be negligible, yielding a linear model (i.e., linear in the inputs) for the operating range. The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces. Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error. The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanism. © 2012 Springer-Verlag London Limited.Ítem Tuning of adaptive weight depth map generation algorithms: Exploratory data analysis and design of computer experiments (DOCE)(SPRINGER, 2013-09-01) Acosta, Diego; Barandiaran, Inigo; Congote, John; Ruiz, Oscar; Hoyos, Alejandro; Grana, Manuel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosIn depth map generation algorithms, parameters settings to yield an accurate disparity map estimation are usually chosen empirically or based on unplanned experiments. Algorithms' performance is measured based on the distance of the algorithm results vs. the Ground Truth by Middlebury's standards. This work shows a systematic statistical approach including exploratory data analyses on over 14000 images and designs of experiments using 31 depth maps to measure the relative influence of the parameters and to fine-tune them based on the number of bad pixels. The implemented methodology improves the performance of adaptive weight based dense depth map algorithms. As a result, the algorithm improves from 16.78 to 14.48 % bad pixels using a classical exploratory data analysis of over 14000 existing images, while using designs of computer experiments with 31 runs yielded an even better performance by lowering bad pixels from 16.78 to 13 %. © 2012 Springer Science+Business Media, LLC.Ítem Understanding the performance of new amine-functionalized mesoporous silica materials for CO2 adsorption(American Chemical Society, 2014-09-01) BUILES, SANTIAGO; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosÍtem Hybrid aminopolymer-silica materials for efficient CO2 adsorption(ROYAL SOC CHEMISTRY, 2015-01-01) López-Aranguren, P.; Builes S.; Fraile, J.; López-Periago, A.; Vega, L.F.; Domingo, C.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe present work focuses on the development of a new eco-efficient chemical method for the polymerization of aziridine to hyperbranched polyethyleneimine (PEI) into mesoporous silica by using compressed CO2 as a solvent, reaction medium and catalyst. PEI was in situ grafted into MCM-41 and silica gel substrates, with pore diameters of 3.8 and 9.0 nm, respectively. The optimal polymerization conditions were found by varying the reaction pressure (1.0-10 MPa), temperature (25-45°C) and time (20-400 min). The thermal stability analysis indicated that aminopolymer chains were covalently attached on the amorphous silica surface. The described compressed CO2 route for the synthesis of high amine content hybrid products (6-8 mmolN g-1) is a very fast method, with processing times in the order of few minutes even at very low working pressures (1.0 MPa), being a step forward in the design of efficient hybrid aminopolymer nanocomposites for CO2 capture. The adsorptive behavior of the prepared hybrid materials was experimentally established by recording the N2 (-196°C) and CO2 (25, 50 and 75°C) adsorption isotherms. Results were compared to molecular simulation studies performed using Grand Canonical Monte Carlo for either N2 or CO2 adsorbed on amino modified MCM-41, thus helping to elucidate the predominant PEI configuration present in the functionalized materials. © The Royal Society of Chemistry 2015.Ítem Collaborative Networked Virtual Surgical Simulators (CNVSS) Implementing Hybrid Client-Server Architecture: Factors Affecting Collaborative Performance(MIT PRESS, 2015-01-01) Diaz, Christian; Trefftz, Helmuth; Quintero, Lucia; Acosta, Diego A.; Srivastava, Sakti; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosCurrently, surgical skills teaching in medical schools and hospitals is changing, requiring the development of new tools to focus on (i) the importance of the mentor's role, (ii) teamwork skills training, and (iii) remote training support. Collaborative Networked Virtual Surgical Simulators (CNVSS) allow collaborative training of surgical procedures where remotely located users with different surgical roles can take part in the training session. To provide successful training involving good collaborative performance, CNVSS should guarantee synchronicity in time of the surgical scene viewed by each user and a quick response time which are affected by factors such as users' machine capabilities and network conditions. To the best of our knowledge, the impact of these factors on the performance of CNVSS implementing hybrid client-server architecture has not been evaluated. In this paper the development of a CNVSS implementing a hybrid client-server architecture and two statistical designs of experiments (DOE) is described by using (i) a fractional factorial DOE and (ii) a central composite DOE, to determine the most influential factors and how these factors affect the collaboration in a CNVSS. From the results obtained, it was concluded that packet loss, bandwidth, and delay have a larger effect on the consistency of the shared virtual environment, whereas bandwidth, server machine capabilities, and delay and interaction between factors bandwidth and packet loss have a larger effect on the time difference and number of errors of the collaborative task.Ítem Sensitivity analysis in optimized parametric curve fitting(EMERALD GROUP PUBLISHING LIMITED, 2015-03-02) Ruiz, Oscar E.; Cortes, Camilo; Acosta, Diego A.; Aristizabal, Mauricio; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosPurpose-Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications. In the literature, several approaches have been proposed to solve this problem. However, previous works lack formal characterization of the curve fitting problem and assessment on the effect of several parameters (i.e. scalars that remain constant in the optimization problem), such as control points number (m), curve degree (b), knot vector composition (U), norm degree (k ), and point sample size (r) on the optimized curve reconstruction measured by a penalty function ( f ). The paper aims to discuss these issues. Design/methodology/approach-A numerical sensitivity analysis of the effect of m, b, k and r on f and a characterization of the fitting procedure from the mathematical viewpoint are performed. Also, the spectral (frequency) analysis of the derivative of the angle of the fitted curve with respect to u as a means to detect spurious curls and peaks is explored. Findings-It is more effective to find optimum values for m than k or b in order to obtain good results because the topological faithfulness of the resulting curve strongly depends on m. Furthermore, when an exaggerate number of control points is used the resulting curve presents spurious curls and peaks. The authors were able to detect the presence of such spurious features with spectral analysis. Also, the authors found that the method for curve fitting is robust to significant decimation of the point sample. Research limitations/implications-The authors have addressed important voids of previous works in this field. The authors determined, among the curve fitting parameters m, b and k, which of them influenced the most the results and how. Also, the authors performed a characterization of the curve fitting problem from the optimization perspective. And finally, the authors devised a method to detect spurious features in the fitting curve. Practical implications-This paper provides a methodology to select the important tuning parameters in a formal manner. Originality/value-Up to the best of the knowledge, no previous work has been conducted in the formal mathematical evaluation of the sensitivity of the goodness of the curve fit with respect to different possible tuning parameters (curve degree, number of control points, norm degree, etc.). © Emerald Group Publishing Limited.Ítem Analysis of CO2 Adsorption in Amine-Functionalized Porous Silicas by Molecular Simulations(American Chemical Society, 2015-06-01) BUILES, SANTIAGO; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosÍtem Analysis of CO2 adsorption in amine-functionalized porous silicas by molecular simulations(American Chemical Society, 2015-06-01) Builes S.; López-Aranguren, P.; Fraile, J.; Vega, L.F.; Domingo, C.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosWe present the results of a combined experimental-molecular simulations approach concerning the capacity for CO2 adsorption of aminosilica hybrid products synthesized using supercritical fluids. Two porous supports were examined for amine functionalization, an ordered mesoporous silica (MCM-41) and a disordered silica gel (SG40). The textural properties of the studied materials were analyzed by low-temperature N2 adsorption-desorption isotherms and compared to those of molecular simulations using the grand canonical Monte Carlo simulation method. The CO2 adsorption capacity of these materials was evaluated by recording CO2 adsorption isotherms up to 100 kPa. Molecular simulations of the CO2 adsorption behavior of selected samples were performed to gain a fundamental understanding of the effect of functionalization. This study shows that in the functionalized materials, the distance between nitrogen atoms of the grafted amines is a critical factor for the occurrence of CO2 chemisorption, providing some insight into key parameters for designing adsorbent materials for CO2 capture and separation. The relationship between the adsorption results with N2 and CO2 allow us to compare the potential applications of the materials in CO2 adsorption and separation processes. A correlation of the N2 adsorption at a given pressure with the CO2 adsorption at a different pressure allowed the prediction of which materials will perform well for these processes. The hybrid products with high amine density have desirable features required for industrial sorbents, such as an enhanced CO2 adsorption capacity and selectivity. © 2015 American Chemical Society.Ítem Collaborative design model review in the AEC industry(Springer-Verlag France, 2016-01-01) Carcamo, Juan Gonzalo; Trefftz Gomez, Helmuth; Acosta Maya, Diego Andres; Botero- B, Luis-F; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe end result of this research is an application created using freely available tools applied to a case scenarioto perform review meetings by different specialists in real time.Ítem Control of emissions in an internal combustion engine: first approach for sustainable design(Springer-Verlag France, 2016-08-01) Amaya, A.F.D.; Torres, A.G.D.; Acosta, D.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosA mathematical model of emissions was developed in a Twingo D7F engine. The effects of variations in compression ratio, fuel/air equivalence ratio, spark advanced and combustion duration under pollutant emissions were studied. Analysis and data collection were performed in an engine bank using a data acquisition system integrated to an Interactive Engineering Environment. A control strategy was implemented to guarantee emissions reduction.Ítem Degradation of Yellow 12 Dye in Industrial Wastewater using Zero-Valent Iron, Hydrogen Peroxide and Ultraviolet Radiation(Centro de Informacion Tecnologica, 2016-09-17) GIL PAVAS EDISON; Medina, J.; Dobrosz-Gómez, I.; Gómez, Miguel Angel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe Fenton heterogeneous process in a fluidized bed reactor using Zero Valent Iron (ZVI), in the metallic state, for the treatment of textile wastewater has been used an analyzed. The aim of this work was to optimize the following...Ítem First and second thermodynamic law analyses applied to spark ignition engines modelling and emissions prediction(Springer-Verlag France, 2016-11-01) Duque Amaya, A.F.; Díaz Torres, A.G.; Acosta Maya, D.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosA mathematical and numerical model of flow and combustion process for spark ignition engines is developed using the principles of the first and second law of thermodynamic. Availability (exergy) analysis is applied to cylinder of a spark ignition engine during the combustion process using a two-zone combustion model. Special attention is given to identification and quantification of irreversibility of combustion process and energy available basing on the isooctane fuel explosion. To predict emissions generation (greenhouse gases) a skeletal mechanism including 32 species and 61 reactions was developed and tested for different engine operations and exergy destructions.Ítem Electrochemical Degradation of Acid Yellow 23 by Anodic OxidationOptimization of Operating Parameters(American Society of Civil Engineers (ASCE), 2016-11-01) GilPavas, Edison; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosIn this study, the electrochemical oxidation (EO) process was implemented and optimized to effectively decolorize and degrade wastewater containing Acid Yellow 23 (Y23). The experiments were carried out in a laboratory-scale batch cell reactor, with monopolar configuration of electrodes, made of graphite (anode) and titanium (cathode). The response surface methodology (RSM), coupled with Box-Behnken experimental design (BBD), was used to evaluate the single and interactive effects of different variables of the EO process on (1)degradation percentages of both chemical oxygen demand (%DCOD) and color (%DC) and (2)energy consumption (EC). Thus, the following experimental factors were considered: initial dye concentration (40-100mg/L), current density (10-20mA/cm2), and conductivity (1,000-4,000S/cm). Thus, the subsequent conditions were found to be optimal for decolorization and degradation of Y23: initial dye concentration = 100mg/L; current density = 20mA/cm2; and conductivity = 4,000S/cm. At these conditions, the EO process allowed to reach approximately 99% of color degradation and 76% of COD degradation. Because NaCl was used as an electrolyte, chorine formation was monitored, and its effect on %DC and %DCOD was also evaluated.Ítem Electrochemical degradation of acid yellow 23 by anodic oxidation: optimization of operating parameters(American Society of Civil Engineers (ASCE), 2016-11-01) Gil, Edison Hernán; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosÍtem Geodesic-based manifold learning for parameterization of triangular meshes(Springer-Verlag France, 2016-11-01) Acosta, D.A.; Ruiz, O.E.; Arroyave, S.; Ebratt, R.; Cadavid, C.; Londono, J.J.; Acosta, Diego A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosReverse Engineering (RE) requires representing with free forms (NURBS, Spline, B,zier) a real surface which has been point-sampled. To serve this purpose, we have implemented an algorithm that minimizes the accumulated distance between the free form and the (noisy) point sample. We use a dual-distance calculation point to / from surfaces, which discourages the forming of outliers and artifacts. This algorithm seeks a minimum in a function that represents the fitting error, by using as tuning variable the control polyhedron for the free form. The topology (rows, columns) and geometry of the control polyhedron are determined by alternative geodesic-based dimensionality reduction methods: (a) graph-approximated geodesics (Isomap), or (b) PL orthogonal geodesic grids. We assume the existence of a triangular mesh of the point sample (a reasonable expectation in current RE). A bijective composition mapping allows to estimate a size of the control polyhedrons favorable to uniform-speed parameterizations. Our results show that orthogonal geodesic grids is a direct and intuitive parameterization method, which requires more exploration for irregular triangle meshes. Isomap gives a usable initial parameterization whenever the graph approximation of geodesics on be faithful. These initial guesses, in turn, produce efficient free form optimization processes with minimal errors. Future work is required in further exploiting the usual triangular mesh underlying the point sample for (a) enhancing the segmentation of the point set into faces, and (b) using a more accurate approximation of the geodesic distances within , which would benefit its dimensionality reduction.
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