Thesis (Ph. D.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1998. / Includes bibliographical references (p. 161-172). / Michael Anthony Casey. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 209-224). / People have intertemporal biases towards choices that result in immediate gratification versus delayed rewards. The social context can accentuate or downplay preferences towards virtues or vices when making choices in the moment. Especially in our modern world where social networks are virtually accessible at anytime, from anywhere, how our day-today decisions are affected by the "always-on" connection to our social networks via mobile devices is an open question. By understanding the dimensions of these social forces, we can utilize the just-in-time social cloud to nudge people towards decisions that have long term benefits for health and finances, while counterbalancing the forces of the marketers that trigger our impulses towards immediate temptations that we may regret later. This work presents an empirical inquiry into the effect of just-in-time social influences in human decision-making. In order to understand these effects and discover their parameters, I design and deploy real-world experiments with the just-in-time social cloud using mobile phones as platforms for just-in-time social influence. The Open Transaction Network forms the basis of generating just-in-time social networks based on the transactions shared by people in the context of commerce. The Open Transaction Network is extended to several systems to conduct real-world experiments involving real choices. By augmenting mobile commerce applications with just-in-time social networks, I design a mobile commerce environment that can socially influence our just-in-time choices. The Open Credit Card Application Framework augments existing methods of payment by using transactions as triggers to enable mobile applications that facilitate just-in-time decisions or reflections. Friends within communities show significant similarity in their hourly transaction behaviors. Varying manifestations of the just-in-time social cloud (individual friends, groups of friends and popularity information) can be used to nudge people's choices in the dimensions of taste, price and time as they decide. / by Kwan Hong Lee. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1993. / Includes bibliographical references (leaves 85-86). / by Mark David Halliday. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2008. / Includes bibliographical references (p. 97-108). / This thesis presents External Legibility: a property of user interfaces that affects the ability of non-participating observers to understand the context of a user's actions. Claims of its value are supported with arguments from the social sciences and human-computer interaction literature; research in designing tangible user interfaces; and an experiment comparing the external legibility of four interaction techniques. / by Jamie B. Zigelbaum. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1994. / Includes bibliographical references (leaves 58-60). / by Christopher Harton Perry. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 43-44). / This thesis develops the use of additive assembly of press-fit digital materials as a new rapid-prototyping process. Digital materials consist of a finite set of parts that have discrete connections and occupy discrete space. Part geometries were designed and fabricated at different scales from different materials, including hierarchical voxels which connect across different scales. All parts were designed to be vertically assembled with top and bottom connections. Digital materials are discussed as a new way for building physically reconfigurable, multi-material 3D structures. The parts were designed with press-fit connectors to build reversible assemblies to take full advantage of reuse and recycling. This document starts by describing some current technologies in the fields of rapid-prototyping and personal fabrication. The concept for a press-fit digital materials is defined and explained. Many part designs are documented, including conductor and insulator parts for SOIC-pitch 3D circuits and hierarchical assemblies. This thesis concludes with the design and concept for assembly machine to automate building functional digital materials. / by Jonathan Ward. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1994. / Includes bibliographical references (leaves 64-68). / by Paul Jay Dworkin. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 59-64). / This thesis proposes a novel framework called transient imaging for image formation and scene understanding through impulse illumination and time images. Using time-of-flight cameras and multi-path analysis of global light transport, we pioneer new algorithms and systems for scene understanding through time images. We demonstrate that our proposed transient imaging framework provides opportunities to accomplish tasks that are well beyond the reach of existing imaging technology. For example, one can infer the geometry of not only the visible but also the hidden parts of a scene, enabling us to look around corners. Traditional cameras estimate intensity per pixel I(x, y). Our transient imaging camera prototype captures a 3D time-image I(x, y, t) for each pixel and uses an ultra-short pulse laser for flash illumination. Emerging technologies are supporting cameras with a temporal-profile per pixel at picosecond resolution, allowing us to capture an ultra-high speed time-image. This time-image contains the time profile of irradiance at a sensor pixel. The speed of light is relevant at these imaging time scales, and the transient properties of light transport come into play. In particular we furnish a novel framework for reconstructing scene geometry of hidden planar scenes. We experimentally corroborated our theory with free space hardware experiments using a femtosecond laser and a picosecond accurate sensing device. The ability to infer the structure of hidden scene elements, unobservable by both the camera and illumination source, will create a range of new computer vision opportunities. / by Ahmed Kirmani. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 89-93). / Over the past decade, computationally powerful audio communication devices have become commonplace. Mobile devices have high storage capacity for digital audio, and smartphones or networked PDAs can be used to stream internet radio and download podcasts. However, applications that allow mobile devices to be used for synchronous communication (such as person-to-person audio interaction and listening to broadcast synchronous audio) are distinct from applications that allow stored audio playback. To demonstrate the benefits of more fluidity in mobile user interfaces between asynchronous audio and synchronous audio playback, I have implemented a new user interface approach - audio scanning - that merges these data types in a single user interface. A combined interface must solve two different research problems. Asynchronous messaging queues grow longer without constant user intervention. Synchronous audio, on the other hand, can be disruptive and transient. To address these problems, a timing heuristic is used in audio scanning to allow sporadic yet controlled delivery of organized audio bursts. / (cont.) To lessen the burden of user interaction with a graphical user interface on a mobile device, a single-button user interface allows control of audio presentation. Two exploratory systems implementing an audio scanning interface are described, allowing comparison to alternate audio systems and approaches. The first implementation, Hearplay, demonstrates the utility of audio scanning in a social audio appliance, designed to be available as an always-on system. The second implementation, Hearwell, demonstrates a use of audio scanning on a mobile phone to help individuals achieve wellness goals. The design and utility of the scanning interface is critiqued for both implementations. / by Patrick Sean Wheeler. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2001. / Includes bibliographical references (p. 71-73). / Tracking multiple people using cameras is similar to the well-studied problem of tracking multiple radar or sonar echoes. This thesis shows that current camera-based tracking algorithms convert each image in a video sequence to a list of targets through a segmentation step, and pass this target set to a traditional multiple-point-target tracking algorithm. Various tracking vision-based strategies as well as point tracking strategies are discussed. Bayesian solutions to the point-tracking problem are well understood, because the generative models need describe the dynamics of simple point objects. In addition, the radar tracking problem assumes that measurements are noise corrupted positions, which makes it easy to cast the tracking problem in a Bayesian framework. Unlike radar, cameras report observations as images. Though point object dynamics can still be used to describe the hidden state of targets, the observation model is an image formation process. As such, the typical solution to tracking in the camera-based tracking community is to reduce each image to a point set, where each point corresponds to a potential target. However, this step introduces uncertainty that is usually not modeled. This thesis proposes a Bayesian person-tracking algorithm which models the entire process of tracking, from the dynamics of the targets to the formation of easy to compute image transforms. An approximate Bayesian tracking algorithm based on Variational Bayes is developed. All the benefits of a Bayesian framework including modeling of the certainty of the recovered results and model selection are taken advantage of. The resulting person tracking algorithm can operate on extremely poor quality imagery. In addition, the tracker can compute the number of targets in the scene automatically as a side effect of its Bayesian formulation. / by Ali Rahimi. / S.M.