Money and Credit With Limited Commitment and Theft

We study the interplay among imperfect memory, limited commitment, and theft, in an environment that can support monetary exchange and credit. Imperfect memory makes money useful, but it also permits theft to go undetected, and therefore provides lucrative opportunities for thieves. Limited commitment constrains credit arrangements, and the constraints tend to tighten with imperfect memory, as this mitigates punishment for bad behavior in the credit market. Theft matters for optimal monetary policy, but at the optimum theft will not be observed in the model. The Friedman rule is in general not optimal with theft, and the optimal money growth rate tends to rise as the cost of theft falls.

Enter the Circle: Blending Spherical Displays and Playful Embedded Interaction in Public Spaces

Public displays are used a variety of contexts, from utility driven information displays to playful entertainment displays. Spherical displays offer new opportunities for interaction in public spaces, allowing users to face each other during interaction and explore content from a variety of angles and perspectives. This paper presents a playful installation that places a spherical display at the centre of a playful environment embedded with interactive elements. The installation, called Enter the Circle, involves eight chair-sized boxes filled with interactive lights that can be controlled by touching the spherical display. The boxes are placed in a ring around the display, and passers-by must “enter the circle” to explore and play with the installation. We evaluated this installation in a pedestrianized walkway for three hours over an evening, collecting on-screen logs and video data. This paper presents a novel evaluation of a spherical display in a public space, discusses an experimental design concept that blends displays with embedded interaction, and analyses real world interaction with the installation

Adverse Selection, Segmented Markets, and the Role of Monetary Policy

A model is constructed in which trading partners are asymmetrically informed about future trading opportunities and where spatial and informational frictions limit arbitrage between markets. These frictions create an inefficiency relative to a full information equilibrium, and the extent of this inefficiency is affected by monetary policy. A Friedman rule is optimal under a wide range of circumstances, including ones where segmented markets limit the extent of monetary policy intervention.Adverse Selection; Monetary Policy; Search

How are emergent constraints quantifying uncertainty and what do they leave behind?

The use of emergent constraints to quantify uncertainty for key policy relevant quantities such as Equilibrium Climate Sensitivity (ECS) has become increasingly widespread in recent years. Many researchers, however, claim that emergent constraints are inappropriate or even under-report uncertainty. In this paper we contribute to this discussion by examining the emergent constraints methodology in terms of its underpinning statistical assumptions. We argue that the existing frameworks are based on indefensible assumptions, then show how weakening them leads to a more transparent Bayesian framework wherein hitherto ignored sources of uncertainty, such as how reality might differ from models, can be quantified. We present a guided framework for the quantification of additional uncertainties that is linked to the confidence we can have in the underpinning physical arguments for using linear constraints. We provide a software tool for implementing our general framework for emergent constraints and use it to illustrate the framework on a number of recent emergent constraints for ECS. We find that the robustness of any constraint to additional uncertainties depends strongly on the confidence we can have in the underpinning physics, allowing a future framing of the debate over the validity of a particular constraint around the underlying physical arguments, rather than statistical assumptions

The Impact of Demographics on Housing and Non-Housing Wealth in the United States

Equity in housing is a major component of household wealth in the United States. Steady gains in housing prices over the last several decades have generated large potential gains in household wealth among homeowners. Mankiw and Weil (1989) and McFadden (1993b) have argued that the aging of the US population is likely to induce substantial declines in housing prices, resulting in capital losses for future elderly generations. However, if households can anticipate changes in housing prices, and if they adjust their non-housing savings accordingly, then welfare losses in retirement could be mitigated. This paper focuses on two questions: (1) Are housing prices forecastable from current information on demographics and housing prices?; and (2) How are household savings decisions affected by capital gains in housing? We use metropolitan statistical area (MSA) level data on housing prices and demographic trends during the 1980's and find mixed evidence on the forecastability of housing prices. Further, we use data on five-year savings rates from the Panel Study of Income Dynamics and find no evidence that households engage in changing their non-housing savings in response to expectations about capital gains in housing. Thus, the projected decline in housing prices could result in large welfare losses to current homeowners and large intergenerational equity differences.

GlobalFestival: Evaluating Real World Interaction on a Spherical Display

Spherical displays present compelling opportunities for interaction in public spaces. However, there is little research into how touch interaction should control a spherical surface or how these displays are used in real world settings. This paper presents an in the wild deployment of an application for a spherical display called GlobalFestival that utilises two different touch interaction techniques. The first version of the application allows users to spin and tilt content on the display, while the second version only allows spinning the content. During the 4-day deployment, we collected overhead video data and on-display interaction logs. The analysis brings together quantitative and qualitative methods to understand how users approach and move around the display, how on screen interaction compares in the two versions of the application, and how the display supports social interaction given its novel form factor

Exploratory ensemble designs for environmental models using k-extended Latin Hypercubes

Copyright © 2015 John Wiley & Sons, Ltd.publication-status: AcceptedOpen Access articleIn this paper we present a novel, flexible, and multi-purpose class of designs for initial exploration of the parameter spaces of computer models, such as those used to study many features of the environment. The idea applies existing technology aimed at expanding a Latin Hypercube (LHC) in order to generate initial LHC designs that are composed of many smaller LHCs. The resulting design and its component parts are designed so that each is approximately orthogonal and maximises a measure of coverage of the parameter space. Designs of the type advocated for in this paper are particularly useful when we want to simultaneously quantify parametric uncertainty and any uncertainty due to the initial conditions, boundary conditions, or forcing functions required to run the model. This makes the class of designs particularly suited to environmental models, such as climate models that contain all of these features. The proposed designs are particularly suited to initial exploratory ensembles whose goal is to guide the design of further ensembles aimed at, for example, calibrating the model. We introduce a new emulator diagnostic that exploits the structure of the advocated ensemble designs and allows for the assessment of structural weaknesses in the statistical modelling. We provide illustrations of the method through a simple example and describe a 400 member ensemble of the Nucleus for European Modelling of the Ocean (NEMO) ocean model designed using the method. We build an emulator for NEMO using the created design to illustrate the use of our emulator diagnostic test.Engineering and Physical Sciences Research Council (EPSRC