Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, May, 2020 / Cataloged from the official PDF of thesis. / Includes bibliographical references (pages 51-57). / Machine learning (ML) has increasingly been used to address the growing burden of mental illness and lack of access to quality mental health care. Recently such models have been applied to online data, such as social media postings to augment mental health screening. Despite the potential of these methods, online ML classifiers still perform poorly in multi-class settings. In this thesis, we propose the usage of novel document embeddings and mental health based user embeddings for triaged suicide risk screening. Machine learning to infer suicide risk and urgency is applied to a dataset of Reddit users in which the risk and urgency labels were derived from crowdsource consensus. We show that the document embedding approach outperforms count-based baselines and a method based on word importance, where important words were identified by domain experts. We examine interpretable features and methods that help to discern and explain risk labels. Finally, we find, using a Latent Dirichlet Allocation (LDA) topic model, that users labeled at-risk for suicide post about different topics to the rest of Reddit than non-suicidal users. / by Noah C. Jones. / S.M. / S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, September, 2020 / Cataloged from the official PDF version of thesis. / Includes bibliographical references (pages 99-102). / This thesis describes the design of a novel modular acoustic communication device for underwater wireless communication. The ocean plays a vital role in the global climate system and biosphere, providing a wealth of biodiversity and resources. Human exploitation, pollutants, and contaminants have already impacted the deepest trenches of the ocean. Yet most of this impact remains invisible - the depth and breadth of the ocean, the opacity of water to light, and the lack of mass-deployable ocean instrumentation, mean that current observations are wildly under sampled in space and time. Even given suitable instruments, a major challenge remains: how to get the data home. Given the opacity of sea water to radio, and the complexity and expense of underwater cabling, audio communication is in may ways the low hanging fruit. Unfortunately, most commercial audio communication systems are both extremely expensive and more powerful than needed for many, if not most, monitoring requirements. / They are also proprietary, a frustrating barrier to development of novel devices. As a result, these off-the-shelf systems are ill-suited to the global multi-scale instrumentation challenges of the future. In what follows we document the design, development, and testing of a low-cost, high-efficiency, modular, and fully open-sourced acoustic communication system. This system is specifically intended for mass deployment, with particular emphasis on standardized hardware and software interfaces. Crucially, this design prioritizes cost and simplicity over performance - as such, this system does not aim to replace the current crop of commercially available systems, but rather to provide a new kind of tool specifically for scalable deployments of low-cost instruments. / Functionally, the system is composed of three core modules: a power management unit; a central processing unit; and a family of interchangeable acoustic transceiver units operating across a spectrum of transmission frequencies. The resulting design should be of valuable use to the scientific community, environmental agencies, citizen scientists, and anyone who needs to transport low-bandwidth data through the ocean at extremely low cost. / by Charlene Xia. / S.M. / S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, September, 2020 / Cataloged from the official PDF version of thesis. / Includes bibliographical references. / We explore the vision of closed-loop bio-digital interfaces for human augmentation, where the bio-digital system allows for both sensing and writing biological information to the body. Current-generation wearable devices sense an individual's physiological data such as heart rate, respiration, electrodermal activity, and EEG, but lack in sensing their biological counterparts, which drive the majority of individual's physiological signals. On the other hand, biosensors for detecting biochemical markers are currently limited to one-time use, are non-continuous and don't provide flexibility in choosing which biomarker they sense. We believe that the future for wearable biosensors lies in going beyond specific sensing capabilities and becoming a wearable "lab" on body, where a small device can offer a fully integrated and re-configurable system that mimics several processes usually performed in the laboratory for clinical diagnostics and analysis of human health. To illustrate our vision of having a lab on body, we prototyped "Wearable Lab" a bio-digital platform for sensing biochemical and digital data from saliva. Our platform contains digital sensors such as an IMU for activity recognition, as well as an automated system for continuous sampling of biomarkers from saliva by leveraging existing paper-based biochemical sensors. The platform could aid with longitudinal studies of biomarkers and early diagnosis of diseases. We present example data collected from the device, show a preliminary evaluation, and discuss the limitation of our platform. / by Pat Pataranutaporn. / S.M. / S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, September, 2020 / Cataloged from the official PDF version of thesis. / Includes bibliographical references (pages 66-71). / The hostile environments of space will require that human life beyond Earth be mediated by many advanced technologies and the many operationally prescriptive systems needed to manage them. Such sociotechnical systems will be characterized by hierarchy, routine, and continuous monitoring. Any humans living in space will spend the entirety of their time under conditions characterized by such systems. Under constant surveillance, totalizing hierarchy, and circumscribed routines, the prospects for democratic social relations appear dim. I offer up several frames that can be used to consider social relations among future spacefarers. By considering perspectives on technology studies, group psychological processes, and legal institutions I explore the question of democratic equality in space from multiple perspectives. I suggest that contemporary discussions of designs for future spacefaring society should center on how those designs will influence democratic equality, and I offer some preliminary sketches of what this might look like. I view my contributions as synthesis and reframing. My hope is that this work begins to bring subject matter experts who do not typically apply their expertise to space to do so. / by David Colby Reed. / S.M. / S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, September, 2020 / Cataloged from the official PDF version of thesis. / Includes bibliographical references (pages 127-136). / Digital fabrication enables complex designs to be realized with improved speed, precision, and cost compared to manual techniques. Additive manufacturing, for example, is one of the leading methods for rapid prototyping and near net shape part production. Extension to full scale structures and systems, however, remains a challenge, as cost, speed and performance present orthogonal objectives that are inherently coupled to limited material options, stochastic process errors, and machine-based constraints. To address these issues, this thesis introduces new materials that physically embody attributes of digital systems, scalable methods for automating their assembly, and a portfolio of use cases with novel, full-scale structural and robotic platforms. First, I build on the topic of discrete materials, which showed a finite set of modular parts can be incrementally and reversibly assembled into larger functional structures. / I introduce a new range of attainable properties, such as rigidity, compliance, chirality, and auxetic behavior, all within a consistent manufacturing and assembly framework. These discretely assembled mechanical metamaterials show global continuum properties based on local cellular architectures, resulting in a system with scalability, versatility, and reliability similar to digital communication and computation. Next, I present a new kind of material-robot system to enable methods of assembly automation. Rather than relying on global motion control systems for precision, mobile robots are designed to operate relative to their discrete material environment. By leveraging the embedded metrology of discrete materials, these relative robots have reduced complexity without sacrificing extensibility, enabling the robots to build structures larger and more precise than themselves. / Multi-robot assembly is compared to stationary platforms to show system benefits for cost and throughput at larger scales. Finally, I show a range of discretely assembled systems that blur the boundary between structure and robotics. Full-scale demonstrations include statically reconfigurable bridges, supermileage racecars, and morphing aero and hydrodynamic vehicles. Performance scaling is projected to new regimes, using case studies of turbine blades, airships, and space structures. These discrete systems demonstrate new, disruptive capabilities not possible within the limits of traditional manufacturing. / by Benjamin Eric Jenett. / Ph. D. / Ph.D. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M., Massachusetts Institute of Technology, Department of Architecture and Planning, Program in Media Arts and Sciences, 2008 / Includes bibliographical references (leaves 88-89). / Using 10 weeks of data from a couple living in an instrumented home, we report on the potential of context-aware power management for energy saving. We identify an opportunity to save on heating and cooling using a system we propose for just-in-time heating and cooling based on travel distance computation from GPS-enabled mobile phones. Analyzing GPS travel data from eight participants (8-12 weeks each) and heating and cooling characteristics from 4 homes, we report results of running computer simulations estimating potential energy savings of a system that could augment existing manual and programmable thermostats. Although manual and programmable thermostats can save large amounts of energy when used properly, studies have shown that well over 40% of U.S. homes may not use energy-saving setbacks when homes are unoccupied. We estimate that using a GPS-enabled thermostat might lead to savings of as much as 7% for some households that do not regularly use the setback features afforded by manual and setback thermostats, without requiring any change in behavior. For some end users, providing one extra bit of information each day could lead to savings as high as 9%, and additional persuasive strategies could save up to 15%. We then report on the implementation of a prototype system and pilot testing of the user interface. We propose five design guidelines for a just-in-time heating and cooling system. / by Manu Gupta. / S.M. / S.M. Massachusetts Institute of Technology, Department of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M. in Media Technology, Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2019 / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 69-74). / Most of current wearable devices used for health monitoring (e.g. Fitbit) are composed of bulky rigid electronics that are not customizable and are too rigid for the skin. To overcome such limitations, a modular system based on thin and stretchable electronic modules was proposed. To link modules together, a novel four pin sliding connector was designed, fabricated, integrated into an stretchable electronic circuit and characterized. The first part of the thesis focused on investigating different stretchable conductive materials that could be integrated into soft rubber substrates. Two materials were tested. First, a commercial silver ink was deposited onto polyurethane rubber (PUR), showing high conductivity but minimum stretchability (below 3% strain). Second, serpentine shaped FPCs were designed and integrated into a silicone substrate, showing stretchability up to 160-170% strain with minimum changes in conductivity (below 30%). Additionally, a tensile cycling test showed stable electromechanical behavior up to 3,500 cycles at 30% maximum tensile strain. The second part of this work addressed the design, fabrication and testing of a novel system for modular stretchable electronics. A four pin sliding connector to enable I2C communication was fabricated by assembling 3D printed parts with brass components manufactured with an EDM cutter. The mechanism could be easily integrated within the previously made stretchable FPC serpentines and demonstrated excellent electromechanical performance. A sample module could be stretched until complete serpentine failure (120% strain) with resistance values across the four pins lower than 2[omega]. Furthermore, the device evaluation on a treadmill showed changes in resistance lower than 4.27[omega] during the 15 minute experiments. / Carlos Núñez López. / S.M. in Media Technology / S.M. in Media Technology Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February, 2020 / Cataloged from the official PDF of thesis. / Includes bibliographical references (pages 179-190). / All commercial leg powered prostheses have been, up to this point, a one-size fits-all design, and of those existing systems, none has yet managed to fully achieve biological walking range of motion, torque and power. Yet, no human body is the same as the next. A configurable prosthesis potentially offers improvements in battery run-time, prosthesis mass, acoustic noise, user comfort, and even enables sport and economy modes within the same fundamental hardware. In this thesis, a reaction-force, series-elastic actuator (RFSEA) is presented that is capable of achieving biomimetic ankle and knee kinetics and kinematics during level-ground walking across a range of body masses, heights and walking styles. The platform is configurable to inertial load by swapping a simple-to-manufacture flat-plate composite spring that allows tuning the actuator dynamics to match different user requirements. The RFSEA also comprises a high torque and pole-count drone motor that directly drives a ball screw with a tunable, low-gear ratio lead. The design enables high dynamic range providing a closed-loop, torque-controlled joint that can demonstrate arbitrary levels of impedance. This control fidelity is important to support smooth control in free-space and high-inertial output conditions, such as the swing and late-stance phases of walking, respectively. A simulation framework is presented that defines mechatronic design specifications for the motor, spring, and gear-reduction components. The optimization procedure clamps output joint dynamics to subject-specific biological gait data, and searches for minimum electric energy solutions across the motor, gear-reduction and spring component space. A second optimization procedure then searches for optimal linkage and spring geometry to best approach the design targets as constrained by the availability of discrete drivetrain components. In this thesis, ankle and knee designs are presented with optimized components using biological joint data from a non-amputee subject walking at 2.0m/sec with a body mass equal to 90Kg. For these designed biomimetic joints, system specifications are verified using bench test evaluations, and preliminary human gait studies. / With a minimum viable actuator mass of 1.4Kg, the platform has a nominal torque control bandwidth of 6Hz at 82Nm, a repeated peak torque capacity of 175Nm, peak demonstrated power over 400W (with theoretical limits over 1kW), a 110 degree range of motion, as well as torque and power densities of 125Nm/kg and 286W/kg, respectively. Configured as an ankle-foot prosthesis, there are 35 degrees of dorsifiexion and 75 degrees of plantar flexion, and as a knee the full 110 degrees of flexion are available to enable activities on varied terrain such as stairs and inclines. Walking dynamics are evaluated with a finite state-machine ankle controller piloted by N=3 subjects with below-knee amputation walking at 1.5m/sec on an instrumented treadmill and one subject walking on stairs. In preliminary experiments, net positive work of 0.2J/Kg, peak joint torque of 1.5Nm/Kg, and peak mechanical power of 4.3W/Kg all fall within one standard deviation of the intact-limb biological mean. Configured as an ankle-foot prosthesis, the system mass is 2.2Kg including battery and electronics, and as a knee the system mass is 1.6Kg, making the RFSEA platform the lightest, most adaptable, and most biomimetic leg system yet published. / by Matthew E. Carney. / Ph. D. / Ph. D. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February, 2020 / "February 2020." Cataloged from the official PDF of thesis. / Includes bibliographical references (pages 102-111). / Renowned designer Kenya Hara writes: "Creativity is to discover a question that has never been asked". These questions are commonly discovered early in the design process; an often ambiguous and liminal experience where new information is explored and considered in non-obvious ways to reveal unexpected associations. 'Intelligent' digital technologies such as machine learning are increasingly employed in tools used in the early phases of the design process. These computational techniques undeniably surpass humans at quickly generating numerous designs and calculating 'optimised' responses, but their average-driven approaches are limited when it comes to embracing the serendipity that can inspire creative breakthroughs. How can we develop digital tools to augment this liminal period of the creative process and help designers discover unexpected ideas? / This dissertation explores this question through three new 'Beyond Average' systems that integrate ambiguity and serendipity into digitally-enabled design tools: the Reframe creative prompt tool that juxtaposes language from a designer's notes in surprising ways to provoke new associations between concepts in their project; the Looking Sideways inspiration exploration tool that presents a diverse range of content for each search query and suggests connections between the concepts discovered; and the digitally-augmented Design Daydreams ideation table and post-it note that seamlessly connects the physical and digital content that designers use in their creative processes. These systems were informed by field research and interviews with expert designers and their impact on the design process was evaluated through several interventions in which creative practitioners, entrepreneurs and technologists used the Beyond Average tools to inspire new ideas for their projects. These interventions highlighted that the creative disruptions these tools provoke cannot exist alone; they must be situated in a larger creative process that accommodates for serendipitous interjections and unanticipated ideas. Overall, this research demonstrates how embedding liminality into digital tools creates a space within the design process for serendipitous inspiration and helps designers apply these innovative ideas, pointing towards new questions to consider as we design the future of our creative work. / by Philippa Mothersill. / Ph. D. / Ph. D. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February, 2021 [for thesis before June 2021] / Cataloged from the official PDF version of thesis. / Includes bibliographical references (pages 97-99). / Workflows in Digital Fabrication require coordination across heterogenous computing systems, from the design tools used to describe component geometries to the embedded control systems used to interact with the physical world in order to produce those components. In the state of the art, workflows are typically static and opaque, especially within embedded controllers themselves. This makes them difficult to modify or develop, and places barriers between high level computing and low level control. An opportunity exists to develop an open platform for interoperability and reconfigurability that spans low- and high-level workflow components, that could collapse much of the heterogeneity found in these systems into cohesive representations. To do so, this thesis develops a systems architecture based on reconfigurable graphs of dataflow objects. It embeds virtual dataflow graphs of modular software elements within physical dataflow graphs of modular hardware elements, recasting heterogenous systems as cohesive graphs all the way down. The architecture is reduced to practice across high-level browser computing and low-level embedded control, through mixed networking links. It is deployed on two machine systems: one that collapses path planning and path execution for a small milling machine, marking a departure from the historic use of G Codes, and another that aligns computer vision based measurement with low-level motor control and sensor acquisition, to open access to materials measurement. / by Jake Robert Read. / S.M. / S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences