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Meta-modeling of Lattice Mechanical Responses via Design of Experiments
(Institute of Electrical and Electronics Engineers Inc., 2020-01-01) Montoya-Zapata D.; Acosta D.A.; Cortes C.; Pareja-Corcho J.; Moreno A.; Posada J.; Ruiz-Salguero O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In the context of lattice manufacturing, the problem of mechanical and structural characterization of large lattice domains is relevant. Lattice materials are used in engineering (e.g. in energy absorption and heat conduction) and biomedical (e.g. bone implants and artificial tissues) applications. However, the numerical simulation of large lattice domains is limited by its complicated geometry, which hinders the meshing stage and produces intractable finite element meshes. The existing efforts to simulate large lattice domains are based on the generation of simplified homogeneous domains equipped with material properties that approximate the behavior of the lattice domain equipped with the bulk material. Using this approach, one can estimate the displacements field over the lattice domain using a lighter mesh and a cheaper simulation. However, since stresses are influenced by geometrical conditions, the stresses of the simplified domain do not match the stresses of the lattice domain. As a response to this limitation, this article proposes a methodology based on the systematic use of design of experiments to devise meta-models to estimate the mechanical response of lattice domains. The devised meta-models can be integrated with material homogenization to allow the mechanical characterization of large lattice domains. In this paper, we apply the proposed methodology to develop meta-models for the estimation of the von Mises stress in Schwarz Primitive lattice domains. Results show that the proposed methodology is able to generate efficient and accurate meta-models whose inputs are based on the displacements on the boundary of the Schwarz cell. Therefore, numerical simulations with the homogeneous simplified domain can be used to feed the meta-models. Additional work is still required to integrate the developed meta-models with material homogenization to test large Schwarz Primitive lattice domains under working loads. © 2020 IEEE.
FEA Structural Optimization Based on Metagraphs
(Springer Verlag, 2019-01-01) Montoya-Zapata D.; Acosta D.A.; Ruiz-Salguero O.; Sanchez-Londono D.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
Evolutionary Structural Optimization (ESO) seeks to mimic the form in which nature designs shapes. This paper focuses on shape carving triggered by environmental stimuli. In this realm, existing algorithms delete under - stressed parts of a basic shape, until a reasonably efficient (under some criterion) shape emerges. In the present article, we state a generalization of such approaches in two forms: (1) We use a formalism that enables stimuli from different sources, in addition to stress ones (e.g. kinematic constraints, friction, abrasion). (2) We use metagraphs built on the Finite Element constraint graphs to eliminate the dependency of the evolution on the particular neighborhood chosen to be deleted in a given iteration. The proposed methodology emulates 2D landmark cases of ESO. Future work addresses the implementation of such stimuli type, the integration of our algorithm with evolutionary based techniques and the extension of the method to 3D shapes. © 2019, Springer International Publishing AG, part of Springer Nature.
Assessing the effectiveness of peer instruction in students' understanding of electric circuits concepts
(AMER SOC ENGINEERING EDUCATION, 2019-01-01) Soto Perez R.A.; Ortega-Alvarez J.D.; Streveler R.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
This paper describes the implementation of an active learning strategy, called Peer Instruction, in an undergraduate electric circuit analysis course offered at a large public university in Colombia. Peer Instruction is an instructional approach that fosters students' collaboration to increase conceptual understanding. Data was collected from three sections of the course mentioned above. In two sections, students attended a traditional class format (51 students) while another section (15 students) implemented the Peer Instruction methodology. The research question driving this project was whether Peer Instruction would produce significantly higher learning gains than the traditional blackboard and chalk approach. A difference was determined using a quasi-experimental study comparing the learning gains of the students in the traditional sections (i.e., the control group) versus those of the students in the Peer Instruction section (i.e., the experimental group). The learning gains were measured by pre/post application of an adapted version of the DIRECT concept inventory which was translated into Spanish. Preliminary results suggest that the implementation of a Peer Instruction approach in an electric circuit analysis course improves the performance of students on the adapted version of the DIRECT test. © American Society for Engineering Education, 2019
Using self-determination theory to evaluate faculty professional development programs
(Research in Engineering Education Network, 2019-01-01) Vieira C.; Ortega-Alvarez J.D.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
This paper discusses the challenges of assessing faculty professional development programs and proposes using the self-determination theory to guide the development of an instrument to assess such programs. Previous experiences have shown that some professional development programs may become transformative learning experiences. These programs present unique challenges for assessment. Since the participants may experience a shift in their understanding of specific concepts, they may feel less competent after they have actively participated in a set of learning activities regarding those concepts. In this study, we propose measuring participants' perceptions of the three psychological needs suggested by the self-determination theory: Autonomy, competence, and relatedness. The participants of a professional development workshop on instructional design completed a pretest/posttest instrument designed to assess changes in their perceptions about autonomy, competence, and relatedness in the context of instructional design. This paper presents the preliminary validation of the instrument using factor analysis, checking for internal consistency, and assessing convergent and discriminant validity. Based on the results from these analyses, the research team proposes future directions for the refinement of the instrument and the assessment of professional development programs. Copyright © 2019 Camilo Vieira and Juan David Ortega-Alvarez.
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.
Special session: Fostering change: Application and implications of Palmer's movement approach to change
(Institute of Electrical and Electronics Engineers Inc., 2017-01-01) Streveler R.A.; Pitterson N.P.; Smith K.A.; Ortega-Alvarez J.D.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
According to change literature, the multiplicity of levels and structures that exist within an organization makes organizational change a difficult process. Similarly, many challenges face any attempt to foster change in engineering education, due to the various layers that make up the field. Looking at the evolution of engineering education research (EER) as a field and the individual pathways of engineering education researchers, EER scholars have discussed a model for engineering education reform that draws from Palmer's Movement Approach to change. This special session introduces Palmer's approach as a framework to look at reforms that have already occurred, and envision possible paths for action toward desired changes. © 2017 IEEE.
Statistical tuning of adaptive-weight depth map algorithm
(SPRINGER, 2011-01-01) Hoyos, Alejandro; Congote, John; Barandiaran, Inigo; Acosta, Diego; Ruiz, Oscar; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In depth map generation, the settings of the algorithm parameters to yield an accurate disparity estimation are usually chosen empirically or based on unplanned experiments. A systematic statistical approach including classical and exploratory data analyses on over 14000 images to measure the relative influence of the parameters allows their tuning based on the number of bad-pixels. Our approach is systematic in the sense that the heuristics used for parameter tuning are supported by formal statistical methods. The implemented methodology improves the performance of dense depth map algorithms. As a result of the statistical based tuning, the algorithm improves from 16.78% to 14.48% bad-pixels rising 7 spots as per the Middlebury Stereo Evaluation Ranking Table. The performance is measured based on the distance of the algorithm results vs. the Ground Truth by Middlebury. Future work aims to achieve the tuning by using significantly smaller data sets on fractional factorial and surface-response designs of experiments. © 2011 Springer-Verlag.
Pixel-based Wake Interaction and Power Estimation for a Wind Farm with Irregular Boundary
(2018-10-18) Ohlsen,, G; Ruiz-Salguero O.; Full,, T.; Acosta D.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In the domain of generation of wind turbine energy, it is central to correctly estimate the interactions among thevarious turbines in a wind turbine farm.
From graduate students to faculty: Portraits of balance in the professional development plans of engineering graduate students
(AMER SOC ENGINEERING EDUCATION, 2017-01-01) Ortega-Alvarez J.D.; Streveler R.A.; Fentiman A.W.; Aggarwal H.W.; Biswas S.; Coventry B.S.; Hassan A.-R.; McNamara M.L.; Smriti N.P.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
The job of a college engineering faculty member is multifaceted. Faculty are not only expected to teach and conduct research but also to write proposals, consult, network, engage in administrative duties, and the list continues. The relative importance and time allocated to these different functions vary according to the nature and focus of the institution and the interests of the faculty. However, engineering graduate students aspiring to careers in academe are not usually trained in the multiple facets of the profession. As a result, when they become faculty members they often struggle to find ways to balance the parallel and many times competing demands of these functions. This paper examines the professional development plans of six engineering graduate students with a marked interest in an academic career. These plans are one of the major deliverables of a three-credit graduate course at a large, research-intensive unive rsity. The overarc hing goal of this course, as stated on its syllabus, is to provide students with an opportunity to learn and practice the skills that complement and enhance classroom teaching and learning in a tenure-track faculty position, either at a research-inte nsive university or at an institution that focuses on undergraduate engineering education. The research questions that orientate the study are: What do the professional development plans of engineering graduate students portray about their striving for balance in their future faculty careers? How does writing a professional development plan with expert guidance in a formal class help these students prepare for a faculty position? The analysis of students' professional development plans as qualitative artifacts, under the lens of expectations and values, reveals a wide variety of approaches to the role of faculty. Subsequent individual reflection on these plans allowed researchers to gather insights into why students chose to focus on different perspectives of the faculty job. Finally, a follow-up group conversation with the students shows that beneath these different perceptions and expectations lies the idea of balance, evolved and transformed by the discussions and activities of the course. © American Society for Engineering Education, 2017.
The challenges of assessing transformative learning: Lessons learned from an instructional design workshop for Colombian engineering faculty
(Tempus Publications, 2018-01-01) Ortega-Alvarez, J.D.; Vieira, C.; Sanchez-Pena, M.; Streveler, R.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
The authors designed and delivered a workshop on Instructional Design for Colombian engineering faculty at three different universities. The workshop drew from the backwards design model and scholarly literature on engineering education. The participants were asked to assess the workshop using a pre-post survey with Likert-type items and open-ended questions. Results from the assessment of the first offering of the workshop suggested a change in participants’ perspectives that the instrument could not fully capture. A revised instrument used during the second offering allowed deeper insights into this change. Based on these results, the authors argue that a professional development program can transform faculty’s perspectives, particularly when it is aimed at helping faculty inform their teaching practice using evidence-based educational research. The assessment of such a program must, therefore, move from an incremental to a transformational notion of learning. The research question driving this work was: How can one assess the transformative learning of engineering faculty about instructional design? This experience with Colombian faculty suggests that a transformative learning framework can inform the assessment of participants’ learning in professional development programs for engineering faculty. Preliminary results of the application of this framework suggest that most workshop participants transitioned from a teacher-centered to a learner-centered conception of teaching. © 2018 TEMPUS Publications.
Special Session: Fostering Change Application and Implications of Palmer's Movement Approach to Change
(IEEE, 2017-01-01) Streveler, RA; Pitterson, NP; Smith, KA; Ortega-Alvarez, JD; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
According to change literature, the multiplicity of levels and structures that exist within an organization makes organizational change a difficult process. Similarly, many challenges face any attempt to foster change in engineering education, due to the various layers that make up the field. Looking at the evolution of engineering education research (EER) as a field and the individual pathways of engineering education researchers, EER scholars have discussed a model for engineering education reform that draws from Palmer's Movement Approach to change. This special session introduces Palmer's approach as a framework to look at reforms that have already occurred, and envision possible paths for action toward desired changes.
Knowing our story: Framing a cooperative inquiry project to explore the personal growth of graduate students in engineering education
(AMER SOC ENGINEERING EDUCATION, 2017-01-01) Aleong R.J.; Goldstein M.H.; Ortega-Alvarez J.D.; Rodriguez-Simmonds H.E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
Doctoral education is often described by faculty and graduate students as "a journey", "a learning process", and "a transformative experience". These descriptions speak to the experiential nature of doctoral education which aims at bringing about some change in students to prepare them for their future career. In the research literature, the path and process of becoming an engineering education researcher is an emerging field. In this paper, we present the framing of a co-operative inquiry project to explore our personal growth as graduate students. Co-operative inquiry is a research method in which multiple people share and explore a topic from their own perspectives through collective dialogue, reflection, interrogation, and transformation. Our co-operative inquiry group consisted of the authors of this paper as coresearchers and co-subjects and is situated in our shared interest in graduate education and learning. While we are at different stages of the doctoral program, we have the mutual experience of completing the first year of the program at the same institution. We engaged in cooperative inquiry sessions, focused on learning within ourselves and with others, to make new meaning from our experiences. Reflections during the formative first year of doctoral training were explored as well as reflections and memos generated as part of the inquiry process. Through the co-operative inquiry process, this study offers insight into opportunities for peer-topeer mentorship and learning enrichment in graduate studies. Our insight may support graduate students in discovering and charting their own personal journeys of learning and development in engineering education research. Our future work will be guided by our co-operative inquiry process and structure, with a focus on delving deeper into the aspects that make up our personal and collective story. © American Society for Engineering Education, 2017.
Learning about engineering education research: What conceptual difficulties still exist for a new generation of scholars?
(Institute of Electrical and Electronics Engineers Inc., 2015-01-01) Streveler, R.A.; Pitterson, N.P.; Hira, A.; Rodriguez-Simmonds, H.; Alvarez, J.O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In 2007, Borrego published her groundbreaking work 'Conceptual difficulties experienced by trained engineers learning educational research methods'[1] that described five conceptual difficulties engineering faculty encountered as they began to learn about rigorous research in engineering education. Since Borrego's research was published the engineering education departments have been formed and a new generation of engineering education researchers has emerged. These researchers must tackle the same paradigm shift that faced the engineering faculty in Borrego's study. The research question that guided this study was: 'What conceptual hurdles still exist for the new generation of engineering education researchers?' PhD students in Engineering Education were asked to reflect on their conceptual difficulties during the first semester of their PhD courses and write an end-of-semester reflective paper that summarizes their cognitive journey. The summative reflections were coded using Borrego's conceptual hurdles as a framework. The results of the present study can inform those entering the engineering education research community by highlighting areas that remain problematic and offer strategies that emerging scholars have used to make sense of educational theories and methods. © 2015 IEEE.
Design of computer experiments applied to modeling compliant mechanisms
(DELFT UNIV TECHNOLOGY, FAC INDUST DESIGN ENG, 2010-01-01) Arango, D.R.; Acosta, D.A.; Durango, S.; Ruiz, O.E.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
This article discusses a procedure for force-displacement modeling compliant mechanisms by using a design of computer experiments methodology. This approach produces a force-displacement metamodel that is suited for real-time control of compliant mechanisms. The term metamodel is used to represent a simplified and efficient mathematical model of unknown phenomenon or computer codes. The metamodeling of compliant mechanisms is performed from virtual experiments based on factorial and space filling design of experiments. The procedure is used to modeling the quasi-static behavior of the HexFlex compliant mechanism. The HexFlex is a parallel compliant mechanism for nanomanipulating that allows six degrees of freedom of its moving stage. The metamodel of the HexFlex is performed from virtual experiments by the Finite Element Method (FEM). The obtained metamodel for the HexFlex is linear for the movement range of the mechanism. Simulations of the metamodel were conducted, finding good accuracy with respect to the virtual experiments. © Organizing Committee of TMCE 2010 Symposium.
Temperature regulation of a pilot-scale batch reaction system via explicit model predictive control
(Institute of Electrical and Electronics Engineers Inc., 2015-01-01) Sanchez-Cossio, J.; Ortega-Alvarez, J.D.; Ocampo-Martinez, C.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In this paper, the temperature of a pilot-scale batch reaction system is modeled towards the design of a controller based on the explicit model predictive control (EMPC) strategy. Some mathematical models are developed from experimental data to describe the system behavior. The simplest, yet reliable, model obtained is a (1,1,1)-order ARX polynomial model for which the mentioned EMPC controller has been designed. The resultant controller has a reduced mathematical complexity and, according to the successful results obtained in simulations, will be used directly on the real control system in a next stage of the entire experimental framework.
Parametric curve reconstruction from point clouds using minimization techniques
(2013-01-01) Ruiz, O.E.; Cortés, C.; Aristizábal, M.; Acosta, D.A.; Vanegas, C.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
Curve reconstruction from noisy point samples is central to surface reconstruction and therefore to reverse engineering, medical imaging, etc. Although Piecewise Linear (PL) curve reconstruction plays an important role, smooth (C1-, C2-,?) curves are needed for many applications. In reconstruction of parametric curves from noisy point samples there remain unsolved issues such as (1) high computational expenses, (2) presence of artifacts and outlier curls, (3) erratic behavior of self-intersecting curves, and (4) erratic excursions at sharp corners. Some of these issues are related to non-Nyquist (i.e. sparse) samples. In response to these shortcomings, this article reports the minimization-based fitting of parametric curves for noisy point clouds. Our approach features: (a) Principal Component Analysis (PCA) pre-processing to obtain a topologically correct approximation of the sampled curve. (b) Numerical, instead of algebraic, calculation of roots in point-to-curve distances. (c) Penalties for curve excursions by using point cloud to - curve and curve to point cloud. (d) Objective functions which are economic to minimize. The implemented algorithms successfully deal with self - intersecting and / or non-Nyquist samples. Ongoing research includes self-tuning of the algorithms and decimation of the point cloud and the control polygon.
Faculty Apprentice as a Mentorship Model for Engineering Graduate Students interested in Teaching
(IEEE, 2018-10-03) Ortega, Juan David; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos

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