D-touch: A Consumer-Grade Tangible Interface Module and Musical Applications

We define a class of tangible media applications that can be implemented on consumer-grade personal computers. These applications interpret user manipulation of physical objects in a restricted space and produce unlocalized outputs. We propose a generic approach to the implementation of such interfaces using flexible fiducial markers, which identify objects to a robust and fast video-processing algorithm, so they can be recognized and tracked in real time. We describe an implementation of the technology, then report two new, flexible music performance applications that demonstrate and validate it

INSTITUTIONS AS THE FUNDAMENTAL CAUSE OF LONG-RUN GROWTH

This paper develops the empirical and theoretical case that differences in economic institutions are the fundamental cause of differences in economic development. We first document the empirical importance of institutions by focusing on wo quasi-natural experiments" in history, the division of Korea into two parts with very different economic institutions and the colonization of much of the world by European powers starting in the fifteenth century. We then develop the basic outline of a framework for thinking about why economic institutions differ across countries. Economic institutions determine the incentives of and the constraints on economic actors, and shape economic outcomes. As such, they are social decisions, chosen for their consequences. Because different groups and individuals typically benefit from different economic institutions, there is generally a conflict over these social choices, ultimately resolved in favor of groups with greater political power. The distribution of political power in society is in turn determined by political institutions and the distribution of resources. Political institutions allocate de jure political power, while groups with greater economic might typically possess greater de facto political power. We therefore view the appropriate theoretical framework as a dynamic one with political institutions and the distribution of resources as the state variables. These variables themselves change over time because prevailing economic institutions affect the distribution of resources, and because groups with de facto political power today strive to change political institutions in order to increase their de jure political power in the future. Economic institutions encouraging economic growth emerge when political institutions allocate power to groups with interests in broad-based property rights enforcement, when they create effective constraints on power-holders, and when there are relatively few rents to be captured by power holders. We illustrate the assumptions, the workings and the implications of this framework using a number of historical examples."Development

Eyes-Off Physically Grounded Mobile Interaction

This thesis explores the possibilities, challenges and future scope for eyes-off, physically grounded mobile interaction. We argue that for interactions with digital content in physical spaces, our focus should not be constantly and solely on the device we are using, but fused with an experience of the places themselves, and the people who inhabit them. Through the design, development and evaluation of a series ofnovel prototypes we show the benefits of a more eyes-off mobile interaction style.Consequently, we are able to outline several important design recommendations for future devices in this area.The four key contributing chapters of this thesis each investigate separate elements within this design space. We begin by evaluating the need for screen-primary feedback during content discovery, showing how a more exploratory experience can be supported via a less-visual interaction style. We then demonstrate how tactilefeedback can improve the experience and the accuracy of the approach. In our novel tactile hierarchy design we add a further layer of haptic interaction, and show how people can be supported in finding and filtering content types, eyes-off. We then turn to explore interactions that shape the ways people interact with aphysical space. Our novel group and solo navigation prototypes use haptic feedbackfor a new approach to pedestrian navigation. We demonstrate how variations inthis feedback can support exploration, giving users autonomy in their navigationbehaviour, but with an underlying reassurance that they will reach the goal.Our final contributing chapter turns to consider how these advanced interactionsmight be provided for people who do not have the expensive mobile devices that areusually required. We extend an existing telephone-based information service to support remote back-of-device inputs on low-end mobiles. We conclude by establishingthe current boundaries of these techniques, and suggesting where their usage couldlead in the future

Gamma-rays from Dark Showers with Twin Higgs Models

We consider a twin WIMP scenario whose twin sector contains a full dark copy of the SM hadrons, where the lightest twin particles are twin pions. By analogy to the standard WIMP paradigm, the dark matter (DM) freezes out through twin electroweak interactions, and annihilates into a dark shower of light twin hadrons. These are either stable or decay predominantly to standard model (SM) photons. We show that this 'hadrosymmetric' scenario can be consistent with all applicable astrophysical, cosmological and collider constraints. In order to decay the twin hadrons before the big-bang nucleosynthesis epoch, an additional portal between the SM and twin sector is required. In most cases we find this additional mediator is within reach of either the LHC or future intensity frontier experiments. Furthermore, we conduct simulations of the dark shower and consequent photon spectra. We find that fits of these spectra to the claimed galactic center gamma-ray excess seen by Fermi-LAT non-trivially coincide with regions of parameter space that both successfully generate the observed DM abundance and exhibit minimal fine-tuning.Comment: 45 pages, 11 figures, v2: journal version, extended discussions in Secs. III-V, references adde

Reversal of Fortune: Geography and Institutions in the Making of the Modern World Income Distribution

Among countries colonized by European powers during the past 500 years those that were relatively rich in 1500 are now relatively poor. We document this reversal using data on urbanization patterns and population density, which, we argue, proxy for economic prosperity. This reversal is inconsistent with a view that links economic development to geographic factors. According to the geography view, societies that were relatively rich in 1500 should also be relatively rich today. In contrast, the reversal is consistent with the role of institutions in economic development. The expansion of European overseas empires starting in the 15th century led to a major change in the institutions of the societies they colonized. In fact, the European intervention appears to have created an 'institutional reversal' among these societies, in the sense that Europeans were more likely to introduce institutions encouraging investment in regions that were previously poor. This institutional reversal accounts for the reversal in relative incomes. We provide further support for this view by documenting that the reversal in relative incomes took place during the 19th century, and resulted from societies with good institutions taking advantage of industrialization opportunities.

The Colonial Origins of Comparative Development: An Empirical Investigation

We exploit differences in the mortality rates faced by European colonialists to estimate the effect of institutions on economic performance. Our argument is that Europeans adopted very different colonization policies in different colonies, with different associated institutions. The choice of colonization strategy was, at least in part, determined by whether Europeans could settle in the colony. In places where Europeans faced high mortality rates, they could not settle and they were more likely to set up worse (extractive) institutions. These early institutions persisted to the present. We document evidence supporting these hypotheses. Exploiting differences in mortality rates faced by soldiers, bishops and sailors in the colonies in the 17th, 18th and 19th centuries as an instrument for current institutions, we estimate large effects of institutions on income per capita. Our estimates imply that differences in institutions explain approximately three-quarters of the income per capita differences across former colonies. Once we control for the effect of institutions, we find that countries in Africa or those farther away from the equator do not have lower incomes.