Major field of Study Networked Virtual Reality

Dissertation Handling Heterogeneity in Collaborative Networked Virtual Surgical Simulators

The College of Engineering of Dissertation committee chairperson Dr. Ing. Francisco Botero, Professor of Mechanical Engineering EAFIT

announces the Director of dissertation research Helmuth Trefftz Gómez, Ph.D., Professor of Computer Science final examination of

Christian Diaz León Examining committee Prof. Michael Zyda, D. Sc. for the degree of University of Southern California, Los Angeles, United States

Doctor of Philosophy in Engineering Prof. Dr. Pierre Boulanger, Ph. D., P. Eng. University of Alberta, Alberta, Canada

Prof. Dr. Pablo Figueroa, Ph. D. Thursday, June 25, 2015 Universidad de Los Andes, Bogotá, At 10:00 am in Auditorium 38 – 103 & Sciences Building President of the Board of the Medellin Campus Doctoral Program in Engineering Dean Alberto Rodriguez Garcia

This examination is open to the public COLOMBIA

ABSTRACT

Stand-alone and networked surgical virtual reality based simulators VITAE 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 Doctoral Student Christian Díaz León, M. Sc. development of new tools to focus on: (i) importance of mentors’ role, (Bucaramanga, Colombia, 1983) obtained the B.Sc. in (ii) teamwork skills and (iii) remote training support. For these Biomedical Engineering (2005) at Escuela de Ingeniería de reasons, a surgical simulator should not only allow the training involving a student and an instructor that are located remotely, but Antioquia and CES University, Colombia, and a M.Sc. in also the collaborative training of users adopting different medical Informatics (2009) at Universidad EAFIT, Medellín, Colombia. roles during the training session. Collaborative Networked Virtual In 2006 Christian joined the Virtual Reality Laboratory as Surgical Simulators (CNVSS) allow collaborative training of surgical graduate student under the supervision of Prof. Helmuth procedures where remotely located users with different surgical roles Trefftz. Christian Díaz was a Research Intern at Stanford can take part in the training session. To provide successful training University in 2011. His academic interests are Distributed involving good collaborative performance, CNVSS should handle Virtual Reality, Surgical Simulation, and Simulation in heterogeneity factors such as users’ machine capabilities and Medicine. network conditions, among others. Several systems for collaborative training of surgical procedures have Doctoral Supervisor Prof. Helmuth Trefftz Gómez, Ph. D. been developed as research projects. To the best of our knowledge none has focused on handling heterogeneity in CNVSS. Handling (Medellin, Colombia 1961) obtained a B. Sc. In Computer heterogeneity in this type of collaborative sessions is important Science (1984), an M. Sc. In Computer Science from Maharishi because not all remotely located users have homogeneous internet University of Management (Iowa, USA, 1985) and a Ph.D. in connections, nor the same interaction devices and displays, nor the Electrical and Computer Engineering from Rutgers University same computational resources, among other factors. Additionally, if (2001). Prof. Trefftz is the head of the Virtual Reality heterogeneity is not handled properly, it will have an adverse impact Laboratory and the chair of the Computer Science on the performance of each user during the collaborative session. In Department, both at EAFIT University. His academic interests this document, the development of a context-aware architecture for include Virtual Reality, Augmented Reality, Computer collaborative networked virtual surgical simulators, in order to Graphics and Serious Games. handle the heterogeneity involved in the collaboration session, is proposed. To achieve this, the following main contributions are accomplished in this thesis: (i) Which and how infrastructure heterogeneity factors affect the collaboration of two users performing a virtual surgical procedure were determined and analyzed through a set of experiments involving users collaborating, (ii) a context-aware software architecture for a CNVSS was proposed and implemented. The architecture handles heterogeneity factors affecting collaboration, applying various adaptation mechanisms and finally, (iii) A mechanism for handling heterogeneity factors involved in a CNVSS is described, implemented and validated in a set of testing scenarios.