Inflation Targets as a Stabilisation Device

Over 80% of countries using explicit inflation targets in 2000 were doing so either as part of a disinflation strategy, or when inflation was neither low nor stable. Our illustrative theoretical model suggests annual revisions to short-run targets are endogenous to inflation outcomes during disinflation as long as the policymaker cares about misses from both the short-run target and a long-run target. Furthermore, target revisions will are larger when the target is undershot compared to when the target is overshot. We confirm the result using cross-country panel estimates from a unique data-set of inflation target misses in 60 countries in the 1990s. During disinflation it is therefore relatively difficult to separate decisions about target-setting from implementation. Short-term targets on a disinflation path may be more akin to conditional forecasts than policy rules, but their publication may nevertheless increase transparency and hence help policymakers to achieve lower inflation.

Turbulence coefficients and stability studies for the coaxial flow or dissimiliar fluids

Analytical investigations of fluid dynamics problems of relevance to the gaseous core nuclear reactor program are presented. The vortex type flow which appears in the nuclear light bulb concept is analyzed along with the fluid flow in the fuel inlet region for the coaxial flow gaseous core nuclear reactor concept. The development of numerical methods for the solution of the Navier-Stokes equations for appropriate geometries is extended to the case of rotating flows and almost completes the gas core program requirements in this area. The investigations demonstrate that the conceptual design of the coaxial flow reactor needs further development

Flow in a two-dimensional channel with a rectangular cavity

Flow characteristics in two dimensional channel with rectangular cavit

Unit Root Testing in a Central Bank

Central bank economists have to understand and forecast macroeconomic time series. A serious problem that they face is that those series are often trended or a.ected by persistent innovations to the process. To try to get round this problem, or at least to understand its possible e.ects, it is common to test whether series are stationary. These tests are often called unit-root tests.1 In this handbook we discuss such testing. A model-builder should use appropriate econometric techniques. In order to choose between alternative estimators, the model-builder needs to think carefully about the relevant theory and the available data. But economic theory is rarely unambiguous in its implications for the data generating process. Subjecting the data to pre-estimation testing can help to gauge the relevance of different theories and possible data problems.Unit, Root, Testing, Central Bank

Monetary Policy and Data Uncertainty: A Case Study of Distribution, Hotels and Catering Growth

This paper is a case study of the real world monetary policy data uncertainty problem. The initial and the latest release for growth rates of the distribution, hotels and catering sector are combined with official data on household income and two surveys in a state-space model. Though important to the UK economy, the distribution, hotels and catering sector is apparently difficult to measure. One finding is that the initial release data is not important in predicting the latest release. It could be that the statistical office develop the initial release as a building block towards the final release rather than an estimate of it. Indeed, there is multicollinearity between the initial release and the retail sales survey, which would then contain the same early available information. A second finding is that the estimate of the later release is sensitive to the estimate of the average historical growth rate. This means that establishing priors for this parameter and testing for shift structural breaks should be very important.Data Uncertainty; Distribution Sector; Kalman Filter; Monetary Policy

Vibrational characteristics of bell plates

University of Technology, Sydney. Faculty of Science.Two thin aluminium plates of specific shape - a composite rectangle/equilateral triangle and a simple equilateral triangle - have been found, when constructed with and held at handles, to radiate a steady state and virtually pure tone, when struck. This property, along with the capacity to manipulate the amplitude, onset and decay of the tone, make the plates suitable for use in musical performance, with the composite shape being used in the manufacture of pitched sets of Belleplates®. Using experimental and computational techniques, these handheld instruments, collectively known as bell plates, were studied here to determine the possible origin of their tone-producing mechanisms. Their mode shapes and vibrational dynamics were compared with those of two non-ringing plates, whose dimensions vary only slightly from those of the bell plate group. The shapes of these non-ringing plates - here termed transient bell plates - are a composite rectangle/isosceles triangle and a simple isosceles triangle. As with the bell plates, they are held at stems or handles. Representations of the shapes of the lowest vibrational modes of the four ringing and non-ringing plates were obtained using Chladni patterns, in which sand grains are used to highlight any nodal regions occurring in a given mode. The mode shape of the ringing mode in the bell plates was identified as an unbroken nodal line in the shape of a U-curve. This curve separates a central oscillating region from two symmetrically-positioned outer regions oscillating out-of-phase with the central area. The mode shape of the equivalent mode in the transient plates is similarly divided into central and outer regions, but these are not divided by a single unbroken curve. Instead, the central antinode in the equivalent mode of the transient plate is outlined by two straight lines on either side of the central axis. The mode shapes found in the two bell plates and the two transient plates were then verified, and their dynamics analyzed, by the use of Finite Element Modelling (FEM). The FEM results of this research show that the ringing mode dominates the vibrational spectra of the two bell plates, verifying the almost pure-tone characteristics of these plates. The spectra of the two transient plates are also dominated by a single mode, which in those plates does not radiate acoustically. With further FEM analysis, features were discovered which differentiate bell plate modal dynamics from those of the non-ringing plates, highlighting characteristics of possible tone-production mechanism in the former. In the ringing mode of the bell plates, greater deformations around the horizontal and central vertical axes were found compared to those in the equivalent transient plate modes. Strain energy density, concentrated at the top centre of the bell plates in this mode, is clearly more dissipated across the area of the transient plates. An orderly alignment of out-of-plane displacement vectors in the belleplate is absent in its non-ringing counterpart. The value of Poisson's Ratio - a measure of the coupling of perpendicular flexural motions in a material - is found to be critical to the presence of the ringing mode's unbroken U-curve but not to that of the broken nodal lines in the transient plates. These comparisons highlight certain features of bell plate vibrational dynamics which are believed to be characteristic of effective tone-generation mechanisms. Future experimental and computational work could reveal further qualitative and quantitative characteristics in both plate types, thus extending and refining an understanding of their significant differences

Laminar mixing of heterogeneous axisymmetric coaxial confined jets Final report

Laminar mixing of heterogeneous axisymmetrical coaxial confined jets for application to nuclear rocket propulsio

Monetary Policy Forecasting in a DSGE Model with Data that is Uncertain, Unbalanced and About the Future

If theory-consistent models can ever hope to forecast well and to be useful for policy, they have to relate to data which though rich in information is uncertain, unbalanced and sometimes forecasts from external sources about the future path of other variables. One example from many is financial market data, which can help but only after smoothing out irrelevant short-term volatility. In this paper we propose combining different types of useful but awkward data set with a linearised forward-looking DSGE model through a Kalman Filter fixed-interval smoother to improve the utility of these models as policy tools. We apply this scheme to a model for Colombia.Monetary Policy, DSGE, Forecast, Kalman Filter Classification JEL: F47, E01, C61.

Analytical investigation of incompressible turbulent swirling flow in pipes

Mixing length flow theory for analyzing incompressible turbulent swirling flow in pipe