Repositorio Institucional Universidad EAFIT ::Examinando por Materia "Visualization"

Examinando por Materia "Visualization"

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Albatros Create: an interactive and generative tool for the design and 3D modeling of wind turbines with wavy leading edge
(Springer-Verlag France, 2020-01-01) Arias-Rosales A.; Osorio-Gómez G.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
The shape of a wind turbine blade plays a critical role in the efficiency and robustness of energy production. In particular, the Wavy Leading Edge is a morphology that can be implemented in the blades to improve the operating range in unsteady conditions. The best performance is achieved by fine-tuning the blade geometry to the specific context. An aerodynamic exploration of these kinds of morphologies implies generating and evaluating design iterations. Accordingly, this work presents the development of the generative tool Albatros Create ®. Through interactive visualization, infographics, and centralized parameterization, its goal is to support the geometrical definition of the aerodynamic surfaces of horizontal-axis turbines with or without a wavy leading edge. New airfoil profiles can be created, and 3D models of the rotors designed can be automatically generated. The software was implemented in the design of two rotors which were then recreated in a benchmarking analysis with four other softwares. None of the four managed to generate the smooth surfaces in fully-editable models that were achieved with Albatros Create. This work aims at empowering the research community with a user-friendly tool for exploring rotor designs through virtual prototypes. This can help to integrate further the design, modeling, and optimization stages, addressing a wider audience and facilitating the implementation of Wavy Leading Edge morphologies. © 2020, Springer-Verlag France SAS, part of Springer Nature.
DC term filtering techniques in digital holography
(SPIE-INT SOC OPTICAL ENGINEERING, 2004-01-01) Garcia-Sucerquia, J.; Ramirez, J.A.H.; Prieto, D.V.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
In numerical hologram reconstruction like in optical holography, there exist different diffraction orders, which many times produce difficulties for the image visualizations. In numerical reconstruction, the filtering of the DC term, or zero order diffraction, provides an improved utilization of the dynamic range of the visualization systems, which is needed for the right displaying purposes of reconstructed images. In the case of the in-line set-ups, the zero diffraction order has even more devastating effects because it does not allow reconstructing the images itself as in Gabor's holograms, so it is necessary to attempt a filtering of this DC term. In this work is shown a qualitative assessment of different techniques of DC term filtering applied to numerical reconstruction of Fresnel's holograms recorded by means of off-line set-ups.
Flow visualization approach for periodically reversed flows
(Begell House Inc., 2012-01-01) Botero, F.; Guzmán, S.; Hasmatuchi, V.; Roth, S.; Farhat, M.; Mecánica Aplicada
An unconventional tuft visualization method, along with an image processing technique adapted to the flow conditions, is proposed and implemented on a reduced-scale model of a Francis-type reversible pump-turbine in three different turbine stages such as turbine mode, runaway mode, and turbine break mode. The main goal of this technique is to visualize the complex flow developed during a rotating stall phenomenon. Fluorescent monofilament wires along with high-speed image processing and pressure sensors were installed in the narrow and vaneless gap between the impeller blades and guide vanes. Pressure fluctuations were analyzed along with tuft visualization to describe the flow with and without a rotating stall. The implemented tuft visualization method gives an adjusted qualitative description of the undergoing phenomena, making different flow behaviors such as backflow, high turbulences, recirculation, etc., evident. © 2012 by Begell House, Inc.
Fluid-structure coupling using lattice-Boltzmann and fixed-grid FEM
(ELSEVIER SCIENCE BV, 2011-08-01) Garcia, Manuel; Gutierrez, Jorge; Rueda, Nestor; Mecánica Aplicada
This paper presents a method for the fluid-structure interaction by a hybrid approach that uses lattice-Boltzmann method (LBM) for the fluid dynamics analysis and fixed-grid FEM (FGFEM) for the structural analysis. The method is implemented in a high performance platform using GPUs to provide a high level of interactivity with the simulation. The solution uses the same Cartesian grid for both solvers. The coupling between both methods is accomplished by mapping the macroscopic pressure, velocity or momentum values from the LBM simulation into the corresponding nodes of the FGFEM structural problem. In spite of being based on a Cartesian grid, both solvers take into account the effect of curve boundaries. Also the effect of a moving boundary is considered in the fluid simulations. The examples presented in this paper show that the accuracy of the solution is as the same level of the finite volume method of the finite element method. On the other hand, the performance of the parallel implementation of the proposed method is of the order that allows real-time visualisation of the computing values for two-dimensional problems. © 2011 Elsevier B.V. All rights reserved.
Fringe visibility analysis with different scale apertures in speckle photography
(TAYLOR & FRANCIS LTD, 2001-09-15) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
The use of different scale aperture pupils for image recording in speckle photography is analysed. In particular a double-exposure specklegram is considered. The ensemble-average intensity in the Fourier plane is analytically derived and fringe visibility is investigated. The theoretical results are verified by in-plane displacement translation experiments.
Interactive visualization of volumetric data with WebGL in real-time
(2011-01-01) Congote, J.; Segura, A.; Kabongo, L.; Moreno, A.; Posada, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This article presents and discusses the implementation of a direct volume rendering system for the Web, which articulates a large portion of the rendering task in the client machine. By placing the rendering emphasis in the local client, our system takes advantage of its power, while at the same time eliminates processing from unreliable bottlenecks (e.g. network). The system developed articulates in efficient manner the capabilities of the recently released WebGL standard, which makes available the accelerated graphic pipeline (formerly unusable). The dependency on specially customized hardware is eliminated, and yet efficient rendering rates are achieved. The Web increasingly competes against desktop applications in many scenarios, but the graphical demands of some of the applications (e.g. interactive scientific visualization by volume rendering), have impeded their successful settlement in Web scenarios. Performance, scalability, accuracy, security are some of the many challenges that must be solved before visual Web applications popularize. In this publication we discuss both performance and scalability of the volume rendering by WebGL ray-casting in two different but challenging application domains: medical imaging and radar meteorology. © 2011 ACM.
Low altitude wind simulation over mount saint helens using NASA SRTM digital terrain model
(2007-01-01) Garcia, M.J.; Boulanger, P.; Garcia, M.J.; Boulanger, P.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
On February 11, 2000, the Shuttle Radar Topography Mission (SRTM) was launched into space as part of one of the pay load of the Shuttle Endeavor. Using a new radar sweeping technique most of the Earth's surfaces was digitized in 3D in approximately 10 days. SRTM acquired enough data during its mission to obtain a near-global high-resolution database of the Earth's topography. This paper describe how this revolutionary data set can be used to simulate anywhere around the Earth low altitude wind conditions for various atmospheric conditions. More specifically, we will describe the various processing steps necessary to convert this high-resolution terrain model provided by the SRTM database into a Computational Fluid Dynamic (CFD) volumetric mesh that is compatible with an open source CFD solver called OpenFOAM running in parallel on large West-Grid supercomputers. This work is the result of a new virtual wind-tunnel under development at the University of Alberta. In the paper, we present wind flow over the MountSaint Helens in the United States for a simple wind flow boundary condition. © 2006 IEEE.
Memberships Networks for High-Dimensional Fuzzy Clustering Visualization
(Springer Verlag, 2019-01-01) Ariza-Jiménez L.; Villa L.F.; Quintero O.L.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Visualizing the cluster structure of high-dimensional data is a non-trivial task that must be able to deal with the large dimensionality of the input data. Unlike hard clustering structures, visualization of fuzzy clusterings is not as straightforward because soft clustering algorithms yield more complex clustering structures. Here is introduced the concept of membership networks, an undirected weighted network constructed based on the fuzzy partition matrix that represents a fuzzy clustering. This simple network-based method allows understanding visually how elements involved in this kind of complex data clustering structures interact with each other, without relying on a visualization of the input data themselves. Experiment results demonstrated the usefulness of the proposed method for the exploration and analysis of clustering structures on the Iris flower data set and two large and unlabeled financial datasets, which describes the financial profile of customers of a local bank. © 2019, Springer Nature Switzerland AG.
Multi-modal interface for a real-time CFD solver
(2007-01-01) Kasakevich, M.; Boulanger, P.; Bischof, W.F.; Garcia, M.; Kasakevich, M.; Boulanger, P.; Bischof, W.F.; Garcia, M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
Advances in computer processing power and networking over the past few years have brought significant changes to the modeling and simulation of complex phenomena. Problems that formerly could only be tackled in batch mode, with their results visualized afterwards, can now be monitored whilst in progress using graphical means. In certain cases, it is even possible to alter parameters of the computation whilst it is running, depending on what the scientist perceives in the current visual output. This ability to monitor and change parameters of the computational process at any time and from anywhere is called computational steering. Combining this capability with advanced multi-modal tools to explore the data produced by these systems are key to our approach. In this paper, we present an advanced multi-modal interface where sonification and 3D visualization are used in a computational steering environment specialized to solve real-time Computational Fluid Dynamics (CFD) problems. More specifically, this paper describes how sonification of CFD data can be used to augment 3D visualization. © 2006 IEEE.
Non-intrusive detection of rotating stall in pump-turbines
(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2014-10-03) Botero, F.; Hasmatuchi, V.; Roth, S.; Farhat, M.; Mecánica Aplicada
When operated far from their optimum conditions, pump-turbines may exhibit strong hydrodynamic instabilities, often called rotating stall, which lead to substantial increase of vibration and risk of mechanical failure. In the present study, we have investigated the flow filed in a model of radial pump-turbine with the help of tuft visualization, wall pressure measurement and structure-borne noise monitoring. As the rotation speed is increased, the machine is brought from its optimum operation to runaway with zero torque on the shaft. The runaway operation is characterized by a significant increase of pressure fluctuation at the rotor-stator interaction frequency. As the speed is further increased, the flow exhibits sub-synchronous instability, which rotates at 70% of the rotation frequency. Tuft visualization clearly shows that, as the instability evolves, the flow in a given distributor channel suddenly stalls and switches to reverse pumping mode in periodic way. We have also investigated the monitoring of the rotating stall with the help of vibration signals. A specific signal processing method, based on amplitude demodulation, was developed. The use of 2 accelerometers allows for the identification of the optimum carrier frequency by computing the cyclic coherence of vibration signals. This non-intrusive method is proved to be efficient in detecting the rotating stall instability and the number of stall cells. We strongly believe that it could be implemented in full scale pump-turbines. © 2014 Elsevier Ltd.
Real-time depth map generation architecture for 3D videoconferencing
(2010-01-01) Congote, J.; Barandiaran, I.; Barandiaran, J.; Montserrat, T.; Quelen, J.; Ferran, C.; Mindan, P.J.; Mur, O.; Tarres, F.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
In this paper we present a reliable depth estimation system which works in real-time with commodity hardware. The system is specially intended for 3D visualization using autostereoscopic displays. The core of this work is an implementation of a modified version of the adaptive support-weight algorithm that includes highly optimized algorithms for GPU, allowing accurate and stable depth map generation. Our approach overcomes typical problems of live depth estimation systems such as depth noise and flickering. Proposed approach is integrated within the versatile GStreamer multimedia software platform. Accurate depth map estimation together with real-time performance make proposed approach suitable for 3D videoconferencing. © 2010 IEEE.
The Structure of Problem Structuring Conversations: A Boundary Games Approach
(Springer Netherlands, 2018-09-01) Velez-Castiblanco, J.; Londono-Correa, D.; Naranjo-Rivera, O.
One of the questions associated with facilitated problem structuring is how the micro level of actors’ multimodal communications, contributes to the emergence of a macro level, framing the possibilities for action in a workshop. This paper shows a way to study this macro level, building the visualization of the conversations’ structure starting from a boundary games theory micro analysis of the interactions. Our empirical evidence comes from following a group of academic consultants working to define a value proposition for their activity. We focus on analyzing two out of nine workshops that were felt diametrically opposite in terms of facilitation and achievements. Moving from the micro towards an upward level, three configurations building the structure are identified—shifting, branching and converging. The work carried out allows us to: (1) visualize the structure of conversations in a problem structuring context, (2) highlight the role of multimodal communications in building the conversations and (3) construct an interpretation bridging the micro and macro readings of a workshop. This knowledge is useful for facilitators guiding the dynamic of a workshop and for researchers looking forward to understanding how micro level interactions build higher levels of the social phenomenon of intervention. © 2018, Springer Nature B.V.
The Structure of Problem Structuring Conversations: A Boundary Games Approach
(Springer Netherlands, 2018-09-01) Velez-Castiblanco, J.; Londono-Correa, D.; Naranjo-Rivera, O.
One of the questions associated with facilitated problem structuring is how the micro level of actors’ multimodal communications, contributes to the emergence of a macro level, framing the possibilities for action in a workshop. This paper shows a way to study this macro level, building the visualization of the conversations’ structure starting from a boundary games theory micro analysis of the interactions. Our empirical evidence comes from following a group of academic consultants working to define a value proposition for their activity. We focus on analyzing two out of nine workshops that were felt diametrically opposite in terms of facilitation and achievements. Moving from the micro towards an upward level, three configurations building the structure are identified—shifting, branching and converging. The work carried out allows us to: (1) visualize the structure of conversations in a problem structuring context, (2) highlight the role of multimodal communications in building the conversations and (3) construct an interpretation bridging the micro and macro readings of a workshop. This knowledge is useful for facilitators guiding the dynamic of a workshop and for researchers looking forward to understanding how micro level interactions build higher levels of the social phenomenon of intervention. © 2018, Springer Nature B.V.
Volume Visual Attention Maps (VVAM) in Ray-Casting Rendering
(IOS Press, 2012) Beristain, Andoni; Congote, John; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This paper presents an extension visual attention maps for volume data visualization, where eye fixation points become rays in the 3D space, and the visual attention map becomes a volume -- This Volume Visual Attention Map (VVAM) is used to interactively enhance a ray-casting based direct volume rendering DVR visualization -- The practical application of this idea into the biomedical image visualization field is explored for interactive visualization

Examinando por Materia "Visualization"

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