UNSW Canberra

Publication Search Results

Now showing 1 - 7 of 7

  • (2001) Hall, Peter; Penev, Spiridon
    Journal Article
    We show that unless the target density is particularly smooth, cross-validation applied directly to nonlinear wavelet estimators produces an empirical value of primary resolution which fails, by an order of magnitude, to give asymptotic optimality. We note, too, that in the same setting, but for different reasons, cross-validation of the linear component of a wavelet estimator fails to give asymptotic optimality, if the primary resolution level that it suggests is applied to the nonlinear form of the estimator. We propose an alternative technique, based on multiple cross-validation of the linear component. Our method involves dividing the region of interest into a number of subregions, choosing a resolution level by cross-validation of the linear part of the estimator in each subregion, and taking the final empirically chosen level to be the minimum of the subregion values. This approach exploits the relative resistance of wavelet methods to over-smoothing: the final resolution level is too small in some parts of the main region, but that has a relatively minor effect on performance of the final estimator. The fact that we use the same resolution level throughout the region, rather than a different level in each subregion, means that we do not need to splice together different estimates and remove artificial jumps where the subregions abut.

  • (1997) Picard, Dominique; Hall, Peter; Penev, Spiridon; Kerkyacharian, Gerard
    Journal Article
    Usually, methods for thresholding wavelet estimators are implemented term by term, with empirical coefficients included or excluded depending on whether their absolute values exceed a level that reflects plausible moderate deviations of the noise. We argue that performance may be improved by pooling coefficients into groups and thresholding them together. This procedure exploits the information that coefficients convey about the sizes of their neighbours. In the present paper we show that in the context of moderate to low signal-to-noise ratios, this lsquoblock thresholdingrsquo approach does indeed improve performance, by allowing greater adaptivity and reducing mean squared error. Block thresholded estimators are less biased than term-by-term thresholded ones, and so react more rapidly to sudden changes in the frequency of the underlying signal. They also suffer less from spurious aberrations of Gibbs type, produced by excessive bias. On the other hand, they are more susceptible to spurious features produced by noise, and are more sensitive to selection of the truncation parameter.

  • (2007) Freyens, Benoit; Oslington, Paul
    Journal Article
    The influence of labor market regulation on employment and other macroeconomic variables is intensely debated across the OECD. In Australia the focus is currently on the employment impact of proposed changes to unfair dismissal provisions. There is surprisingly little research on the magnitude and structure of dismissal costs and this paper presents new data from a major survey of small- and medium-sized Australian enterprises. Dismissal costs are compared for different types of separations, including redundancy, uncontested fires and complex fires. Using the data, we estimate the employment impact of the proposed unfair dismissal changes, which we find likely to be modest.

  • (2005) Oslington, Paul
    Journal Article
    Changes in the military environment and wider society are making increasingly complex ethical demands on Australian Defence Force officers, and this article describes recent developments in ethics education at the Australian Defence Force Academy.

  • (2005) Oslington, Paul
    Journal Article
    In contrast to the focus of the public debate over trade liberalisation on job losses there is a widespread view among economists that unemployment and trade issues should be considered separately. This view cannot be justified theoretically, and ignores the growing number of general equilibrium trade models with unemployment. In a simple model with an exogenous wage floor, trade liberalisation can lead to either gains or losses depending on the production technology, severity of the factor market distortion, factor intensities of the industries, and conditions in trading partners. Definite results can be derived about gains from liberalising trade with lower wage floors, about relative abundance of the unemployed factor dampening losses when trade is liberalised, and about gains when the good which uses the unemployed factor is exported. The theoretical models are then linked to the policy modelling literature, using the example of recent Australian controversies over liberalisation of trade in automobiles and textiles. It is argued that trade liberalisation would be better advanced by including endogenous employment in trade policy simulation exercises and by discussing employment effects rather than brushing them aside as temporary adjustment problems or regional difficulties.

  • (2005) Oslington, Paul
    Journal Article
    A major problem with on-line education in contemporary universities is securing cooperation of teaching staff. This paper argues that even if the benefits of on-line learning are widely recognised, several incentive problems inhibit academic staff participation. These incentive problems include unverifiability of expertise in on-line learning, the firm-specific nature of investments in on-line learning and the team nature of on-line learning. Suggestions are made for remedying each of these problems by correcting the distorted incentives faced by academics and administrators alike.