UNSW Canberra

Publication Search Results

Now showing 1 - 9 of 9

  • (1993) Huang, Xu Benjamin

  • (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.

  • (1995) Tacconi, Luca
    The objective of this thesis is to develop an ecological economic framework for the assessment and establishment of protected areas (PAs) that are aimed at conserving forests and biodiversity. The framework is intended to be both rigorous and relevant to the decision-making process. Constructivism is adopted as the paradigm guiding the research process of the thesis, after firstly examining also positivist philosophy and ‘post-normal’ scientific methodology. The tenets of both ecological and environmental economics are then discussed. An expanded model of human behaviour, which includes facets derived from institutional economics and socioeconomics as well as aspects of neoclassical economics, is outlined. The framework is further developed by considering, from a contractarian view point, the implications of intergenerational equity for biodiversity conservation policies. The issues of intragenerational distribution and allocation are then considered. In this regard, cost-benefit analysis (CBA), as applied to the valuation of forests, PAs, and biodiversity, is critically reviewed. A participatory approach to decision-making, which may also include CBA, is then proposed. The resulting ecological economic framework may be thus summarised: (a) ecosystem use patterns should be chosen on the basis of their sustainability, distributional, and efficiency aspects; (b) systems of PAs should be established in order to achieve minimal intergenerational equity; (c) intragenerational equity requires the correction of the asymmetrical distribution of the costs and benefits arising from the establishment of PAs; (d) the institutional features relevant to the environmental-economic issues being analysed should be considered; and (e) the decision-making process should be participatory and action oriented. The framework is applied to two case studies in Vanuatu. These applications detail (a) stakeholders’ views and trade-offs faced in relation to forest management (b) modes of participatory research and decision-making, (c) forms of compensation that may be adopted in correcting asymmetrical distributions of the costs and benefits of PAs, and (d) institutional influences on ecosystems use and implications for conservation projects. The institutional arrangements developed for the establishment of the PAs are presented. The application of this ecological economic framework has resulted in the formal establishment of one PA and the identification and assessment of five other PAs.

  • (1998) Rolfe, John
    The Choice Modelling technique is an emerging technique which appears to have strengths relative to other non-market valuation techniques. The latter group are important in the assessment of the tradeoffs involved in environmental and resource use tradeoffs. However, the use of these techniques is often criticised where ethical and moral frameworks are involved, where it is unclear how difficult choices are being framed against each other, or where it is unclear how values change according to the scope of the amenity under consideration The primary focus of the thesis is on the development of the Choice Modelling technique, which provides a richer information set to researchers than other techniques such as Contingent valuation method. However, the richness of this data is offset to some degree by the complexity of application, where careful attention is needed for design, application and analytical stages. In this thesis, a series of four Choice Modelling experiments are reported, as well as two small Contingent Valuation experiments. The Choice Modelling experiments were centred on the estimation of values that Australians might hold for rainforest conservation in Vanuatu. In order to frame and scope the tradeoffs of interest within the broad pool of substitute goods (such as rainforest conservation opportunities in other countries), the Choice Modelling technique appeared more suitable than the single tradeoff preservation of the Contingent Valuation method. The results of Choice Modelling experiments involved sets of parameters indicating that the probability of choice depended on a number of attributes used to make up the conservation profiles together with the influence of unobserved attributes. As a willingness-to-pay variable was included within the attributes making up choice profiles, estimates of value were available by predicting how changes in particular attributes could be offset by changes in the willingness-to-pay variable. The major conclusions of the research presented in the thesis were that the involvement with ethical and moral frameworks does not invalidate the use of non-market valuation techniques, and that the Choice Modelling technique has strengths in relation to scooping and framing issues. In particular, the research demonstrates that the information generated from an experiment can be used in an iterative approach to develop more accurate models of choice. As well, the research shows that the amenity of interest, rainforest conservation in Vanuatu, can have positive values for Australian residents relative to other conservation opportunities.