Repositorio Institucional Universidad EAFIT ::Examinando por Autor "Trefftz, H."

Examinando por Autor "Trefftz, H."

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Achieving object persistence in an augmented reality indoor environment
(2003-01-01) Gutiérrez, M.D.; Márquez, A.M.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
In this paper we present a system for achieving object persistence in Augmented Reality Indoors Environments. In AR systems based on the Augmented Reality toolkit without object persistence, virtual objects appear and disappear as the corresponding pattern gets in and out of the user's field of view. Object persistence allows the environment to remember the relative position and orientation of virtual objects, making them appear more stable to the user. We describe object persistence as a series of transformations applied to the objects in a simple indoor environment. We then present the results of a quantitative experiment that shows how interactivity is improved by the use of object persistency.
Adaptive architecture to support context-aware Collaborative Networked Virtual Surgical Simulators (CNVSS)
(SPRINGER, 2014-01-01) Diaz, C.; Trefftz, H.; Quintero, L.; Acosta, D.; Srivastava, S.; Diaz, C.; Trefftz, H.; Quintero, L.; Acosta, D.; Srivastava, S.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
Stand-alone and networked surgical virtual reality based simulators have been proposed as means to train surgical skills with or without a supervisor nearby the student or trainee. However, surgical skills teaching in medicine schools and hospitals is changing, requiring the development of new tools to focus on: (i) importance of mentors role, (ii) teamwork skills and (iii) remote training support. For these reasons a surgical simulator should not only allow the training involving a student and an instructor that are located remotely, but also the collaborative training session involving a group of several students adopting different medical roles during the training session. Collaborative Networked Virtual Surgical Simulators (CNVSS) allow collaborative training of surgical procedures where remotely located users with different surgical roles can take part in a training session. Several works have addressed the issues related to the development of CNVSS using various strategies. To the best of our knowledge no one has focused on handling heterogeneity in collaborative surgical virtual environments. Handling heterogeneity in this type of collaborative sessions is important because not all remotely located users have homogeneous Internet connections, nor the same interaction devices and displays, nor the same computational resources, among other factors. Additionally, if heterogeneity is not handled properly, it will have an adverse impact on the performance of each user during the collaborative session. In this paper we describe the development of an adaptive architecture with the purpose of implementing a context-aware model for collaborative virtual surgical simulation in order to handle the heterogeneity involved in the collaboration session. © 2014 Springer International Publishing.
Adaptive architecture to support context-aware Collaborative Networked Virtual Surgical Simulators (CNVSS)
(SPRINGER, 2014-01-01) Diaz, C.; Trefftz, H.; Quintero, L.; Acosta, D.; Srivastava, S.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Stand-alone and networked surgical virtual reality based simulators have been proposed as means to train surgical skills with or without a supervisor nearby the student or trainee. However, surgical skills teaching in medicine schools and hospitals is changing, requiring the development of new tools to focus on: (i) importance of mentors role, (ii) teamwork skills and (iii) remote training support. For these reasons a surgical simulator should not only allow the training involving a student and an instructor that are located remotely, but also the collaborative training session involving a group of several students adopting different medical roles during the training session. Collaborative Networked Virtual Surgical Simulators (CNVSS) allow collaborative training of surgical procedures where remotely located users with different surgical roles can take part in a training session. Several works have addressed the issues related to the development of CNVSS using various strategies. To the best of our knowledge no one has focused on handling heterogeneity in collaborative surgical virtual environments. Handling heterogeneity in this type of collaborative sessions is important because not all remotely located users have homogeneous Internet connections, nor the same interaction devices and displays, nor the same computational resources, among other factors. Additionally, if heterogeneity is not handled properly, it will have an adverse impact on the performance of each user during the collaborative session. In this paper we describe the development of an adaptive architecture with the purpose of implementing a context-aware model for collaborative virtual surgical simulation in order to handle the heterogeneity involved in the collaboration session. © 2014 Springer International Publishing.
Adaptive architecture to support context-aware Collaborative Networked Virtual Surgical Simulators (CNVSS)
(SPRINGER, 2014-01-01) Diaz, C.; Trefftz, H.; Quintero, L.; Acosta, D.; Srivastava, S.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
Stand-alone and networked surgical virtual reality based simulators have been proposed as means to train surgical skills with or without a supervisor nearby the student or trainee. However, surgical skills teaching in medicine schools and hospitals is changing, requiring the development of new tools to focus on: (i) importance of mentors role, (ii) teamwork skills and (iii) remote training support. For these reasons a surgical simulator should not only allow the training involving a student and an instructor that are located remotely, but also the collaborative training session involving a group of several students adopting different medical roles during the training session. Collaborative Networked Virtual Surgical Simulators (CNVSS) allow collaborative training of surgical procedures where remotely located users with different surgical roles can take part in a training session. Several works have addressed the issues related to the development of CNVSS using various strategies. To the best of our knowledge no one has focused on handling heterogeneity in collaborative surgical virtual environments. Handling heterogeneity in this type of collaborative sessions is important because not all remotely located users have homogeneous Internet connections, nor the same interaction devices and displays, nor the same computational resources, among other factors. Additionally, if heterogeneity is not handled properly, it will have an adverse impact on the performance of each user during the collaborative session. In this paper we describe the development of an adaptive architecture with the purpose of implementing a context-aware model for collaborative virtual surgical simulation in order to handle the heterogeneity involved in the collaboration session. © 2014 Springer International Publishing.
Agents as tutors in augmented reality
(2003-01-01) Álvarez, N.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Interaction between virtual entities and human beings should be similar to the normal interaction between human beings. Verbal interaction is the usual way of interaction among humans, but the interfaces that allow verbal communication between a human being and an agent (virtual human) have a limited vocabulary, need a lot of training and are expensive. In this paper we propose an Augmented Reality System with an unidirectional interface between an agent and a person. By using gestures, animations and adequate texts the agent can show a user how to perform a simple task. We hope that the tests to be conducted will show how useful this unidirectional interface is.
Collaborative and distributed augmented reality in teaching multi-variate calculus
(2006-01-01) Orozco, C.; Esteban, P.; Trefftz, H.; Orozco, C.; Esteban, P.; Trefftz, H.; Universidad EAFIT. Departamento de Ciencias; Educación Matemática e Historia
This article presents the first results of using an Augmented Reality (AR) tool, designed to support tutoring sessions in multi-variate calculus. The tool is used either in a face-to-face setting in which the instructor and the students are collocated or in a distance setting, in which the instructor and students are physically in remote places. The tool was used with two groups of students of Differential Calculus. The students had not been exposed to the concept of equations involving 3 variables and the corresponding surfaces in space. The experience explored how students generalized 2D graphics and equations with their 3D surfaces counterparts with the help of the tool.
Collaborative and distributed augmented reality in teaching multi-variate calculus
(2006-01-01) Orozco, C.; Esteban, P.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
This article presents the first results of using an Augmented Reality (AR) tool, designed to support tutoring sessions in multi-variate calculus. The tool is used either in a face-to-face setting in which the instructor and the students are collocated or in a distance setting, in which the instructor and students are physically in remote places. The tool was used with two groups of students of Differential Calculus. The students had not been exposed to the concept of equations involving 3 variables and the corresponding surfaces in space. The experience explored how students generalized 2D graphics and equations with their 3D surfaces counterparts with the help of the tool.
A collaborative tool for synchronous distance education
(2004-01-01) Agudelo, A.; Escobar, L.; Restrepo, J.; Quiroz, A.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
In this paper we report results of the use of a telepresence application in a simulated distance education setting. The application combines video-conference with a networked virtual environment in which the instructor and the students can experiment with virtual object in a collaborative manner. The teaching for Understanding (TFU) framework is used as the pedagogical approach. Current preliminary results show that the combination of the telepresence application with TFU, can compensate for the lack of physical presence of the instructor in the classroom.
Collaborative virtual environments for teaching physics
(SPRINGER, 2007-01-01) Giraldo, F.; Rojas, Á.M.J.; Esteban, P.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Eafit University created a Telepresence application for distance education. It supports bidirectional audio and video and a shared virtual environment that allows the instructor and students to manipulate virtual objects in a collaborative manner, thereby reinforcing the learning process. In this paper we report the experience of creating new contents and deploying the tool in a Physics course at Universidad del Quindío. The tool was improved an extended in order to include new functionality and make it easier for development teams to create new content. Teaching for Understanding was used as pedagogical framework for course creation and also as a guide to develop the interviews that were used to capture user's perceptions and to asses the improvements in the learning process. The results showed that the use of the tool had a positive impact on the students' understanding of the topics at hand. © 2007 Springer.
Collaborative virtual environments for teaching physics
(SPRINGER, 2007-01-01) Giraldo, F.; Rojas, Á.M.J.; Esteban, P.; Trefftz, H.; Giraldo, F.; Rojas, Á.M.J.; Esteban, P.; Trefftz, H.; Universidad EAFIT. Departamento de Ciencias; Educación Matemática e Historia
Eafit University created a Telepresence application for distance education. It supports bidirectional audio and video and a shared virtual environment that allows the instructor and students to manipulate virtual objects in a collaborative manner, thereby reinforcing the learning process. In this paper we report the experience of creating new contents and deploying the tool in a Physics course at Universidad del Quindío. The tool was improved an extended in order to include new functionality and make it easier for development teams to create new content. Teaching for Understanding was used as pedagogical framework for course creation and also as a guide to develop the interviews that were used to capture user's perceptions and to asses the improvements in the learning process. The results showed that the use of the tool had a positive impact on the students' understanding of the topics at hand. © 2007 Springer.
Design and implementation of a low-cost projected virtual reality system to support learning processes
(Springer Verlag, 2011-01-01) Gómez, R.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Virtual Reality technologies have been successfully incorporated into the learning processes and potential new applications in education are explored continuously. We found that one of the difficulties to popularize its use in the educational context, in countries with emerging and developing economies, is the cost of hardware required to generate satisfactory immersive experience. In this work we considered virtual reality from the perspective of human-computer interaction to support learning processes. The characteristics of low-cost projected virtual reality system (PVR) proposed, combines study and integration of available technology solutions, the development of an image synchronization routine that enables the use of a single video projector and the design of a printable pattern that preserve the state of polarization on the projection screen. © 2011 Springer-Verlag.
Distance interaction in education processes using a Telepresence tool
(SPRINGER-VERLAG BERLIN, 2010-01-01) Giraldo, F.; Jiménez, A.; Trefftz, H.; Restrepo, J.; Esteban, P.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Estudios en Mantenimiento (GEMI)
Distance interaction among educational communities is becoming increasingly important. Courses and talks are shared among institutions and individuals who are located in different places. The Telepresence tool, developed by Eafit and Universidad del Quindío, permits course sharing among the institutions. Instructors from one institution can teach students of the other one, thereby sharing the positive features of each course. In this paper, we present the recent improvements of the Telepresence tool. We also report on the use of the tool in a Multi-Variable Calculus course, designed in accordance to the Teaching for Understanding (TFU) pedagogical framework. © 2010 Springer Science+Business Media B.V.
Distance interaction in education processes using a Telepresence tool
(SPRINGER-VERLAG BERLIN, 2010-01-01) Giraldo, F.; Jiménez, A.; Trefftz, H.; Restrepo, J.; Esteban, P.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Distance interaction among educational communities is becoming increasingly important. Courses and talks are shared among institutions and individuals who are located in different places. The Telepresence tool, developed by Eafit and Universidad del Quindío, permits course sharing among the institutions. Instructors from one institution can teach students of the other one, thereby sharing the positive features of each course. In this paper, we present the recent improvements of the Telepresence tool. We also report on the use of the tool in a Multi-Variable Calculus course, designed in accordance to the Teaching for Understanding (TFU) pedagogical framework. © 2010 Springer Science+Business Media B.V.
Dynamic server allocation in virtual environments, using quadtrees for dynamic space partition
(2003-01-01) Restrepo, A.; Montoya, A.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
In actual applications of virtual environments, one of the problems that has received attention is the way to assign computational resources to those who participate in the system. In most cases, static resource allocation is used. Static allocation is simple but has several limitations, among them, the missutilization of resources. In this paper we present a proof-of-concept of a new system and report the results of experiments with a system that accomplishes dynamic resource allocation by using Quadtrees for space partitioning, in a Shared Virtual Environment.
Evaluation of various strategies to improve the training of a brain computer interface system
(2013-01-01) Jiménez, L.D.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Brain-computer interfaces (BCI) allow for communication between the human brain and computers. They have been used to create systems able to generate control over a software or mechatronic device, becoming an important tool for the rehabilitation of handicapped people, especially for patients with quadriplegia. Due to the importance of BCIs, any attempt to improve their response has a great value. The work described in this paper consists of the evaluation of various stimuli applied to improve the training of a BCI based system. The device is the Emotiv® EPOC which includes a Software Development Kit (SDK) to train the system. During the usual training of the SDK; images, videos, thoughts, movements and gestures were used as stimuli to improve the users' skills for accomplishing specific actions. After the evaluation of these stimuli, they were ranked according to their effectiveness. Finally, a powered wheelchair was controlled using the Emotiv® EPOC by applying the best-ranked stimulus and an assessment protocol was used in order to evaluate the performance of users driving the wheelchair with the BCI, with satisfactory results.
Generation of the business user interface from the association of data patterns, presentation template and interaction model
(Institute of Electrical and Electronics Engineers Inc., 2016-01-01) Trivino, J.I.; Giraldo, W.J.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
An immersive virtual reality training system for mechanical assembly
(2011-01-01) Peniche, A.; Diaz, C.; Trefftz, H.; Paramo, G.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Given the growing evolution of technology, machinery and manufacturing techniques, conventional methodologies for training the workforce are not enough for the current needs. Therefore methodologies capable to accelerate the training process and able to train the trainee in a wide range of scenarios are claimed for the industrial sector. Virtual reality offers an alternative that has been successfully implemented in other industries, and virtual reality based training systems have numerous advantages over the conventional methodologies, making it a very good option. Based on that premise, this paper explores the implementation of an immersive training system for mechanical assembly based on virtual reality for improving the training process. This system was proved to be as effective as the conventional methodology.
Observations about an approximate algorithm for the point robot motion planning problem
(IEEE Computer Society, 2002-01-01) Trefftz, C.; Trefftz, H.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
Observations about an approximate parallel algorithm for the point robot motion planning problem are presented. The algorithm solves not only the original problem, but related problems as well. © 2002 IEEE.
Parallelizing AES on multicores and GPUs
(2011-01-01) Ortega, J.; Trefftz, H.; Trefftz, C.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
The AES block cipher cryptographic algorithm is widely used and it is resource intensive. An existing sequential open source implementation of the algorithm was parallelized on multi-core microprocessors and GPUs. Performance results are presented. © 2011 IEEE.
Remote teaching functional and anatomical concepts skeletal muscle system
(SPRINGER, 2008-01-01) Leon, C.A.D.; Trefftz, H.; Pineda, F.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
In this paper we present the results of using a virtual content developed inside a telepresence application. The application combines video-conference with networked virtual environment allowing an instructor and a group of students to manipulate a virtual object in a collaborative manner. The virtual environment describes bones and muscular structures in order to support teaching of musculoskeletical concepts in a remote physiology class. The virtual environment simulates the movement of flexion and extension of the elbow and the muscular contraction. Current preliminary results show that the content developed within telepresence application can compensate for the lack of physical presence of the instructor in the classroom. © Springer-Verlag Berlin Heidelberg 2007.

Examinando por Autor "Trefftz, H."

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