We introduce heterogeneity in investors' ability to borrow from collateral in a Kiyotaki-Moore style macro model, calibrated to the quintiles of the leverage-ratio distribution of US non-financial firms. Financial amplification intensifies, because of stronger asset price reactions of highly levered investors. (authors' abstract)

The aim of this work is to determine whether any zero temperature features of the scalar potential strongly influence the finite temperature properties of the electroweak phase transition. In particular, we address whether one can get an arbitrarily strong phase transition from zero temperature effects. We investigate a variety of models of varying complexity. For the models we look into, we successfully determine that the vacuum energy difference at zero temperature has a direct influence on the critical temperature. This leads to arbitrarily strong phase transitions, subject to the caveat that sliding behaviour does not occur. What we call sliding behaviour is the scenario in which the broken vacuum destabilises under thermal corrections before reaching the critical temperature. The parameter subspace in which sliding behaviour does occur often leads to significantly weakened phase transitions. For a more detailed investigation of the phase transition one must look at the thermal decay of the false vacuum. Choosing a non-supersymmetric real singlet extension to the Standard Model, called the xSM, we detail by example how one can systematically investigate some non-trivial phase transition properties. The specific model we adopt is the Z2xSM which has a Z2 discrete symmetry imposed on the singlet as well as the Higgs field. We focus on the non-sliding parameter subspace, which has a minimal zero temperature parameter space of only three free parameters. For this setup, the depth of the potential at zero temperature has a one-to-one mapping with the strength of the phase transition at critical temperature so we can trivially choose the strength. This allows for a systematic approach to investigating very strong phase transitions and their connection to the amount of supercooling, latent heat, bubble nucleation rate, and a hydrodynamical friction parameter. We also trace out the parameter region in which runaway bubbles are expected and discuss the implications for gravitational wave production.

M.S.

In a composite sampling procedure initial samples (increments) are drawn from a lot and physically mixed to form composite samples. Subsamples are then taken from these composite samples and tested to determine the lot quality, usually the lot mean, μ_x. Composite sampling procedures typically are employed with bulk materials, for which high testing costs preclude estimation of μ_x using the arithmetic average of values from several individually tested increments. Because of the physical averaging that occurs when increments are mixed to form composite samples, it is possible to estimate μ_x with specified precision with greater economy using a composite sampling procedure than using a noncompositing procedure. This dissertation extends and interprets the work of Brown and Fisher on modeling procedures that involve subsampling mixtures of sampled material. Models are developed for sampling from segmented or nonsegmented lots, allowing for more than one finite composite, testing error, within-increment variability, or two subsampling stages. The result of each model is a formula expressing the variance of the estimator of μ_x in terms of model parameters. Each such formula is contrasted with the corresponding formula derived from the customarily employed random effects linear model. / Ph. D.

"The Fine Topology" C(X,Y) where (Y,d) is a metric space is referred to, in an exercise in [14], as the topology generated by basic open neighborhoods of the form B(f,E) = {g: d(f(x),g(x)) < E(x)} where E is a positive continuous real valued function. So in the fine topology, a function g is close to f if g(x) is continuously close to f(x); whereas in the uniform topology, g(x) must be uniformly close to f(x), that is, within a constant distance of f(x). So the fine topology is an obvious refinement of the uniform topology. This topology has not been extensively studied before, and it is the purpose of this paper to see how the fine topology fits in with the lattice of other well studied topologies on C(X,Y), and to study some properties of this topology in itself. Furthermore, other results on these well studied topologies will-be examined and compared with the fine topology. / Ph. D.

This dissertation presents a discussion of the asymptotic behavior and estimation structure of the H_∞ central controllers in terms of the well-known behavior of the LQG controller and gives some insight into the physics of the H_∞ controller that is often presented in an unclear manner in the current literature. The connections to LQ game theory that underlie this confusion are discussed. Augmented systems that are typically used in disturbance rejection problems are also analyzed. Additionally, a controlled output equation for disturbance rejection is developed based on the physics of the problem rather than the typical ad hoc approaches of the past. These controlled output equations are also appropriate for LQG compensators. In order to verify the proposed approach, an experiment in harmonic and narrowband disturbance rejection using a simply supported steel plate is presented. Discrete-time LQG, and continuous-time H_∞ and LQG controllers that have been transformed to discrete-time are used to determine the attainable performance of each approach. The results indicate that the H_∞ controller provides more damping than either LQG approach and that discrete-time design procedures are necessary for maximum disturbance rejection. / Ph. D.

We provide a comprehensive analysis of the out-of-sample predictive accuracy of different global vector autoregressive (GVAR) specifications based on alternative weighting schemes to address global spillovers across countries. In addition to weights based on bilateral trade, we entertain schemes based on different financial variables and geodesic distance. Our results indicate that models based on trade weights, which are standard in the literature, are systematically outperformed in terms of predictive accuracy by other specifications. We find that, while information on financial linkages helps improve the forecasting accuracy of GVAR models, averaging predictions by means of simple predictive likelihood weighting does not appear to systematically lead to lower forecast errors.

In this paper, we examine international linkages in inflation and short-term interest rates using a global sample of OECD and emerging economies. Using a Bayesian global vector autoregression (GVAR) model, we show that for short-term interest rates both movements in inflation and output play an important role. In advanced countries, however, international factors such as foreign interest rates appear as an important driver of local interest rates. For inflation, we also find evidence for the importance of global factors, such as price developments in other countries, oil prices and the exchange rate. Again, this impact of global factors appears predominately in advanced countries. / Series: Department of Economics Working Paper Series

We compare the performance of the perturbation-based (local) portfolio solution method of Devereux and Sutherland (2010a, 2011) with a global solution method. We find that the local method performs very well when the model is designed to capture stylized macroeconomic facts and countries/agents are symmetric, i.e. when the latter have similar size, face similar risks and trade assets with similar risk properties. It performs less satisfactory when the agents engaged in financial trade are asymmetric. The global solution method performs substantially better when the model is parameterized to match the observed equity premium, a key stylized finance fact. (authors' abstract) / Series: Department of Economics Working Paper Series

This paper examines for the first time the relationship between the net issue values of aggregate bonds, as well as the different bond sectors separately, and economic growth. The other new feature of this study is the usage of quarterly data. Granger causalities are calculated for time series of 15 European countries, the USA, and Japan in order to test if there is a positive relationship between the development of bond markets and economic growth also for shorter time periods. The significant Granger causalities found show the following tendency: Economic growth is causal for net issue values of government bonds, and net issuance of corporate and financial institutions bonds are causal for economic growth. That finding is important for the future architecture of the financial sector, in particular in emerging markets and the new EU member countries. (author's abstract) / Series: EI Working Papers / Europainstitut