Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2017. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 87-92). / Kinesthetic haptic devices can make us feel that we are touching or holding objects that are not actually there by applying a force directly onto a user's body. As a corollary of Newton's third law, these devices are typically attached to the ground or else they would not be able to apply a net force onto a user. Thus, kinesthetic haptic devices typically have small workspaces-the area in which they can be used-or are overly cumbersome and expensive. Consequently, they are incompatible with room-scale virtual reality, which allows users to move and walk within a room. The portable haptics interface overcomes this limitation because its wearable form factor means it's "grounded" directly to a user's back, making it portable. In other words, this device approximates the sensations of a kinesthetic haptic device while also being portable. The haptic device consists of a robotic arm that is mounted on a user's back, and its end-effector is attached to an HTC Vive controller, enabling use with virtual reality. A first example application uses the portable haptics interface to simulate the elasticity of a bow and arrow as a user pulls on the bowstring of a virtual bow. A second application renders haptic feedback for impacts by applying an impulse of in the appropriate direction when a user hits a tennis ball with a racket in virtual reality. In an evaluation, we asked users to shoot targets in virtual reality with and without haptic feedback. Our results suggest that haptic feedback increases spatial presence with a large effect size but does not affect involvement and experienced realism. Our results also suggest several improvements to the ergonomics of the system such as using thicker straps to better distribute the load. In summary, portable kinesthetic haptic devices such as the portable haptics interface provide room-scale virtual reality applications with the sense of touch without constraining users to a chair. / by Andres Calvo. / S.M.

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references. / In this body of work, I present a situated and interactive agent perception system that can index into its world and, through a bidirectional exchange of referential gesture, direct its internal indexing system toward both well-known objects as well as simple visuo-spatial indexing in the world. The architecture presented incorporates a novel method for synthetic human-robot joint attention, an internal and automatic crowdsourcing system that provides opportunistic and lifelong robotic socio-visual learning, supports the bidirectional process of following referential behavior; and generates referential behavior useful for directing the gaze of human peers. This document critically probes questions in human-robot interaction around our understanding of gaze manipulation and memory imprinting on human partners in similar architectures and makes recommendations that may improve human-robot peer-to-peer learning. / by Nicholas Brian DePalma. / Ph. D.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 95-97). / Though there have been remarkable advances in powered prosthesis technology over the past decade, design limitations of commercial electric motors are one of the main bottlenecks in meeting critical device requirements, such as minimum range on a single battery charge and acoustic emission restrictions. Traditional motor design focuses on motor development for operation at specific torques and velocities, but a motor design which minimizes the power loss over the torque-velocity profile of a bionic ankle is more precisely what is needed for our application. Considering the design requirement in this way lays the groundwork for a new design framework. Leveraging this problem statement, we herein develop a new motor design process generalizable to all applications requiring a variable but cyclic torque-velocity profile. We present a motor optimization package for cyclic variable torque-velocity motor design and demonstrate its viability in constrained optimization of a transverse flux motor for use in a bionic ankle. We further evaluate and present the intended use of this transverse flux motor for application in bionic joints, along with advantages and design hurdles of the planned system. / by Cameron Roy Taylor. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 89-95). / The rise of ubiquitous sensing enables the harvesting of massive amounts of data from the physical world. This data is often used to drive the behavior of devices, but when presented to users, it is most commonly visualized quantitatively, as graphs and charts. Another approach for the representation of sensor network data presents the data within a rich, virtual environment. This thesis introduces the concept of Resynthesizing Reality through the construction of Doppelmarsh, the virtual counterpart of a real marsh located in Plymouth Massachusetts, where the Responsive Environments Group has deployed and maintained a network of environmental sensors. By freely exploring such environments, users gain a vivid, multi-modal, and experiential perspective into large, multi-dimensional datasets. We present a variety of approaches to manifesting data in "avatar landscape", including landscapes generated off live video, tinting frames in correspondence with temperature, or representing sensor history in the appearance and behavior of animals. The concept of virtual lenses is also introduced, which makes it easy to dynamically switch sensor-to-reality mapping from within virtual environments. In this thesis, we describe the implementation and design of Doppelmarsh, present techniques to visualize sensor data within virtual environments, and discuss potential applications for Resynthesizing Reality. / by Don Derek Haddad. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 65-67). / A new 'axial-transverse flux' motor (ATFM) topology is of interest to autonomous lower-extremity robotics designers for its high torque density and low winding resistance. Unfortunately, deliberate asymmetries in the design make finite-element modeling of this topology largely intractable. An ATFM prototype was characterized experimentally using a custom dynamometer and controller. The prototype was found to have a torque constant Kt of 7.26 Nm/A and a per-phase winding resistance of 0.59 Ohms. It is characterized by high AC and DC zero-current torque, as well as significant torque ripple (M: 12.9%, SD: 0.6%) when driven with balanced three-phase sinusoidal commutation. A set of optimized commutation waveforms are developed based on an independent phase control strategy, and it is shown that this strategy can eliminate ripple in simulation and reduce it in practice (M: 7.8%, SD: 0.5%), without reduction of mean torque or increased conduction losses relative to sinusoidal commutation. / by Madeleine Rose Abromowitz. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 93-97). / Robots are moving from factories to people's homes taking on the roles of artificial pets, tutors and companions. If we are to have emotionally engaging robots, we must understand how we can design robots that people feel empathy towards. In this work, I explore one design criteria for such robots: implicit life stories or the ability for a robot to experience the world we share, be transformed by that experience and communicate that experience to us. Through the construction of novel robots that can have implicit life-stories, and through human subject studies I show that such robots can evoke empathy. I also show that empathy for robots can impact empathy for other human beings. / by Palash Nandy. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 67-68). / Wisdom of the crowds (WOC) is an old concept that started by recording and aggregating people's estimations. It is one of the useful tools that exists today and allows many estimation applications to work correctly. Moreover, Open algorithms (OPAL) is a useful platform that enables institutions and individuals to share sensitive data, and increases the privacy of the data. In addition, federated learning is a new way to build and generate machine learning models by aggregating their hyperparameters. In this thesis, I show how to combine the three different concepts to build machine learning models on top of OPAL that utilize federated learning on a network. I then extend OPAL to support this new feature and demonstrate how to build a machine learning model using small independent models. / by Abdulrahman Alotaibi. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 105-107). / Planning a city is a complex task that requires collaboration between multiple stakeholders who have different and often conflicting goals and objectives. Researchers have studied the role of technology in group collaboration for many years. It has been noted that when the task between collaborators increases in complexity, such as in a decision-making process, the use of computer technology could enhance, or disturb, the collaboration process. This thesis evaluates whether a Tangible User Interface (TUI) is more effective for multi-objective group decision-making than a Graphical User Interface (GUI). To examine this question, I designed and developed the CityGame framework, a web-based negotiation and decision-support game with a multi-modal interface for an urban planning scenario. The interfaces were evaluated in a within-subjects study with 31 participants of varying background, who were assigned a planning task in a gameplay session. Results show that tangible interfaces have some observable advantages over digital interfaces in this scenario. / by Mohammad K. Hadhrawi. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 9-11). / Scientific managers need to understand the impact of the research they support since they are required to evaluate researchers and their work for funding and promotional purposes. Yet, most of the online tools available to explore publication data, such as Google Scholar (GS), Microsoft Academic Search (MAS), and Scopus, present tabular views of publication data that fail to put scholars in a social, institutional, and geographic context. Moreover, these tools fail to provide aggregate views of the data for countries, organizations, and journals. Here, we introduce Opus, an interactive online platform that integrates, aggregates, and visualizes publication data from GS to present users with publication data at four different scales (e.g., scholars, countries, organizations, and journals). At each scale, Opus provides benchmarked visualizations that facilitate understanding the work of scholars in a social, generational, geographic, and institutional context. We conducted two user studies with a small group of potential users that show supporting evidence for the benefits of our approach. This design study contributes to the relatively unexplored but promising area of using information visualization to explore publication data. / by Almaha Adnan Almalki. / S.M.

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 111-117). / During the gait cycle, the human ankle complex serves as a primary power generator while simultaneously stabilizing the entire limb. These actions are controlled by an intricate interplay of several lower leg muscles that cannot be fully uncovered using experimental methods alone. A combination of experiments and mathematical modeling may be used to estimate aspects of neuromusculoskeletal functions that control human gait. In this research, a three-dimensional neuromuscular model of the human ankle-foot complex based on biplanar fluoroscopy gait analysis is presented. Biplanar fluoroscopy (BiFlo) enables three-dimensional bone kinematics analysis using x-ray videos and bone geometry from segmented CT. Hindered by a small capture volume relative to traditional optical motion capture (MOCAP), BiFlo applications to human movement are generally limited to single-joint motions with constrained range. Here, a hybrid procedure is developed for multi-joint gait analysis using BiFlo and MOCAP in tandem. MOCAP effectively extends BiFlo's field-of-view. Subjects walked at a self-selected pace along a level walkway while BiFlo, MOCAP, and ground reaction forces were collected. A novel methodology was developed to register separate BiFlo measurements of the knee and ankle-foot complex. Kinematic analysis of bones surrounding the knee, ankle, and foot was performed. Kinematics obtained using this technique were compared to those calculated using only MOCAP during stance phase. Results show that this hybrid protocol effectively measures knee and ankle kinematics in all three body planes. Additionally, sagittal plane kinematics for select foot bone segments (proximal phalanges, metatarsals, and midfoot) was realized. The proposed procedure offers a novel approach to human gait analysis that eliminates errors originated by soft tissue artifacts, and is especially useful for ankle joint analysis, whose complexities are often simplified in MOCAP studies. Outcomes of the BiFlo walking experiments helped guide the development of a three-dimensional neuromuscular model of the human ankle-foot complex. Driven by kinematics, kinetics, and electromyography (EMG), the model seeks to solve the redundancy problem, individual muscle-tendon contributions to net joint torque, in ankle and subtalar joint actuation during overground gait. Kinematics and kinetics from BiFlo walking trials enable estimations of muscle-tendon lengths, moment arms, and joint torques. EMG yields estimates of muscle activation. Using each of these as inputs, an optimization approach was employed to calculate sets of morphological parameters that simultaneously maximize the neuromuscular model's metabolic efficiency and fit to experimental joint torques. This approach is based on the hypothesis that the muscle-tendon morphology of the human leg has evolved to maximize metabolic efficiency of walking at self-selected speed. Optimal morphological parameter sets produce estimates of force contributions and states for individual muscles. This research lends insight into the possible roles of individual muscle-tendons in the leg that lead to efficient gait. / by David Allen Hill. / Ph. D.