18 resultados para Branch-and-Price
em University of Queensland eSpace - Australia
Resumo:
A state-contingent model of production under uncertainty is developed and compared with more traditional models of production under uncertainty. Producer behaviour with both production and price risk, in the presence and in the absence of futures and forward markets, is analysed in this state-contingent framework. Conditions for the optimal hedge to be positive or negative are derived. We also show that, under plausible conditions, a risk-averse producer facing price uncertainty and the ability to hedge price risk will never willingly adopt a nonstochastic technology. New separation results, which hold in the presence of both price and production risk, are then developed. These separation results generalize Townsend's spanning results by reducing the number of necessary forward markets by one.
Resumo:
This article studies the comparative statics of output subsidies for firms, with monotonic preferences over costs and returns, that face price and production uncertainty. The modeling of deficiency payments, support-price schemes, and stochastic supply shifts in a state-space framework is discussed. It is shown how these notions can be used, via a simple application of Shephard's lemma, to analyze input-demand shifts once comparative-static results for supply are available. A range of comparative-static results for supply are then developed and discussed.
Resumo:
A telephone survey was conducted in Melbourne and Brisbane to obtain a profile of milk consumption in Australia and determine consumers' attitudes regarding UHT milk. It was anticipated that this survey would reveal the reasons for the low level of UHT milk consumption in Australia. Pasteurised milk was the main milk type used by more than 80% of respondents. For UHT milk this figure was much lower (approximately 10%), even though two thirds of respondents had tried UHT milk. Factors that were found to influence UHT milk consumption included existing milk consumption habits, consumer perception, flavour and price. The majority of non-users of UHT milk stated habit of using other milk type as their main reason for not using UHT milk. Other reasons included poor nutritional value, poor flavour and not real/pure milk, indicating a negative consumer perception of the product. The flavour of UHT milk was identified as a problem, with nearly half of UHT milk users considering it to be worse than the flavour of pasteurised milk. However, a small proportion of UHT milk users preferred the flavour of UHT milk, with the majority of them stating that it was creamier, richer and/or stronger than the flavour of pasteurised milk. Prior to post-farmgate deregulation, price was shown to discourage consumers from using UHT milk. At the time of the survey, post-farmgate prices in Victoria were deregulated resulting in UHT milk being priced below that of pasteurised milk in some instances. This was believed to contribute to a significantly higher market share of the product in Melbourne than in Brisbane.
Resumo:
Agricultural ecosystems and their associated business and government systems are diverse and varied. They range from farms, to input supply businesses, to marketing and government policy systems, among others. These systems are dynamic and responsive to fluctuations in climate. Skill in climate prediction offers considerable opportunities to managers via its potential to realise system improvements (i.e. increased food production and profit and/or reduced risks). Realising these opportunities, however, is not straightforward as the forecasting skill is imperfect and approaches to applying the existing skill to management issues have not been developed and tested extensively. While there has been much written about impacts of climate variability, there has been relatively little done in relation to applying knowledge of climate predictions to modify actions ahead of likely impacts. However, a considerable body of effort in various parts of the world is now being focused on this issue of applying climate predictions to improve agricultural systems. In this paper, we outline the basis for climate prediction, with emphasis on the El Nino-Southern Oscillation phenomenon, and catalogue experiences at field, national and global scales in applying climate predictions to agriculture. These diverse experiences are synthesised to derive general lessons about approaches to applying climate prediction in agriculture. The case studies have been selected to represent a diversity of agricultural systems and scales of operation. They also represent the on-going activities of some of the key research and development groups in this field around the world. The case studies include applications at field/farm scale to dryland cropping systems in Australia, Zimbabwe, and Argentina. This spectrum covers resource-rich and resource-poor farming with motivations ranging from profit to food security. At national and global scale we consider possible applications of climate prediction in commodity forecasting (wheat in Australia) and examine implications on global wheat trade and price associated with global consequences of climate prediction. In cataloguing these experiences we note some general lessons. Foremost is the value of an interdisciplinary systems approach in connecting disciplinary Knowledge in a manner most suited to decision-makers. This approach often includes scenario analysis based oil simulation with credible models as a key aspect of the learning process. Interaction among researchers, analysts and decision-makers is vital in the development of effective applications all of the players learn. Issues associated with balance between information demand and supply as well as appreciation of awareness limitations of decision-makers, analysts, and scientists are highlighted. It is argued that understanding and communicating decision risks is one of the keys to successful applications of climate prediction. We consider that advances of the future will be made by better connecting agricultural scientists and practitioners with the science of climate prediction. Professions involved in decision making must take a proactive role in the development of climate forecasts if the design and use of climate predictions are to reach their full potential. (C) 2001 Elsevier Science Ltd. All rights reserved.
Resumo:
This study identifies and explores a new country of origin (COO) cue, “owned by….” The importance of three extrinsic cues “owned by …,” “made in …” and price was examined using conjoint analysis. Data were collected from a sample of 268 undergraduate students familiar with color televisions. Segments were formed using cluster analysis and analyzed using multiple discriminant analysis. “Owned by …” was found to be important and distinct from the “made in …” cue. Segments based on the two COO cues were identified using importance weights and individual utilities. When segments were formed using individual utilities the individual difference construct, economic nationalism, provided discriminatory power while consumer ethnocentrism did not, supporting the hypothesis that economic nationalism and consumer ethnocentrism differ. Practitioners can now use “owned by …” knowing that it forms an important and distinct marketing tool. Limitations and future research are discussed.
Resumo:
Information on decomposition of harvest residues may assist in the maintenance of soil fertility in second rotation (2R) hoop pine plantations (Araucaria cunninghamii Aiton ex A. Cunn.) of subtropical Australia. The experiment was undertaken to determine the dynamics of residue decomposition and fate of residue-derived N. We used N-15-labeled hoop pine foliage, branch, and stem material in microplots, over a 30-mo period following harvesting. We examined the decomposition of each component both singly and combined, and used C-13 cross-polarization and magic-angle spinning nuclear magnetic resonance (C-13 CPMAS NMR) to chart C transformations in decomposing foliage. Residue-derived N-15 was immobilized in the 0- to 5-cm soil layer, with approximately 40% N-15 recovery in the soil from the combined residues by the end of the 30-mo period. Total recovery of N-15 in residues and soil varied between 60 and 80% for the combined-residue microplots, with 20 to 40% of the residue N-15 apparently lost. When residues were combined within microplots the rate of foliage decomposition decreased by 30% while the rate of branch and stem decomposition increased by 50 and 40% compared with rates for these components when decomposed separately. Residue decomposition studies should include a combined-residue treatment. Based on C-15 CPMAS NMR spectra for decomposing foliage, we obtained good correlations for methoxyl C, aryl C, carbohydrate C and phenolic C with residue mass, N-15 enrichment, and total N. The ratio of carbohydrate C to methoxyl C may be useful as an indicator of harvest residue decomposition in hoop pine plantations.
Resumo:
The Australian energy market is in the final stages of deregulation. These changes have created a dynamic environment which is highly volatile and competitive with respect to both demand and price. Our current research seeks to visualise aspects of the National Energy Market with a view to developing techniques which may be useful in identifying significant characteristics and/or drivers of these characteristics. In order to capture the complexity of the problem we explore a suite of different visualisation techniques, which, when combined into a unified package, highlight aspects of the problem. The particular problem visualised here is "Does the date exhibit characteristics which suggest that the time of day, day of the week, or the season, aflect the variation in demand and/or price?" © Austral. Mathematical Soc. 2005.
Resumo:
Australian heroin markets have recently undergone dramatic change, sparking debate about the nature of such markets. This study aimed to determine the onset, peak and decline of the heroin shortage in New South Wales (NSW), using the most appropriate available methods to detect market level changes. The parameters of the heroin shortage were determined by reviewing: reports of heroin users about availability and price (derived from the existing literature and the Illicit Drug Reporting System); qualitative interviews with injecting drug users, and health and law enforcement professionals working in the illicit drug field; and examining data on heroin seizures over the past decade. There was a marked reduction in heroin supply in NSW in early 2001. An increase in the price of heroin occurred in 2001, whereas it had decreased steadily since 1996. A reduction in purity also occurred, as reported by drug users and heroin seizures. The peak period of the shortage appears to have been January to April 2001. The market appears to have stabilised since that time, although it has not returned to pre- 2001 levels: heroin prices have decreased in NSW for street grams, but not to former levels, and the price of `caps' (street deals) remain elevated. Heroin purity in NSW has remained low, with perhaps a 10% increase above the lowest recorded levels. These data support the notion that the heroin market in NSW underwent significant changes, which appear to have involved a lasting shift in the nature of the market.
Resumo:
The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries: inappropriate incentives bearing on fishers and the ineffective governance that frequently exists in commercial, developed fisheries managed primarily by total-harvest limits and input controls. We contend that much greater emphasis must be placed on fisher motivation when managing fisheries. Using evidence from more than a dozen natural experiments in commercial fisheries, we argue that incentive-based approaches that better specify community and individual harvest or territorial rights and price ecosystem services and that are coupled with public research, monitoring, and effective oversight promote sustainable fisheries.
Resumo:
This paper describes the application of a new technique, rough clustering, to the problem of market segmentation. Rough clustering produces different solutions to k-means analysis because of the possibility of multiple cluster membership of objects. Traditional clustering methods generate extensional descriptions of groups, that show which objects are members of each cluster. Clustering techniques based on rough sets theory generate intensional descriptions, which outline the main characteristics of each cluster. In this study, a rough cluster analysis was conducted on a sample of 437 responses from a larger study of the relationship between shopping orientation (the general predisposition of consumers toward the act of shopping) and intention to purchase products via the Internet. The cluster analysis was based on five measures of shopping orientation: enjoyment, personalization, convenience, loyalty, and price. The rough clusters obtained provide interpretations of different shopping orientations present in the data without the restriction of attempting to fit each object into only one segment. Such descriptions can be an aid to marketers attempting to identify potential segments of consumers.
Resumo:
The debate about the dynamics and potential policy responses to asset inflation has intensified in recent years. Some analysts, notably Borio and Lowe, have called for 'subtle' changes to existing monetary targeting frameworks to try to deal with the problems of asset inflation and have attempted to developed indicators of financial vulnerability to aid this process. In contrast, this paper argues that the uncertainties involved in understanding financial market developments and their potential impact on the real economy are likely to remain too high to embolden policy makers. The political and institutional risks associated with policy errors are also significant. The fundamental premise that a liberalised financial system is based on 'efficient' market allocation cannot be overlooked. The corollary is that any serious attempt to stabilize financial market outcomes must involve at least a partial reversal of deregulation.