Efficient management of backtracking in and-parallelism

A backtracking algorithm for AND-Parallelism and its implementation at the Abstract Machine level are presented: first, a class of AND-Parallelism models based on goal independence is defined, and a generalized version of Restricted AND-Parallelism (RAP) introduced as characteristic of this class. A simple and efficient backtracking algorithm for R A P is then discussed. An implementation scheme is presented for this algorithm which offers minimum overhead, while retaining the performance and storage economy of sequent ial implementations and taking advantage of goal independence to avoid unnecessary backtracking ("restricted intelligent backtracking"). Finally, the implementation of backtracking in sequential and AND-Parallcl systems is explained through a number of examples

Numerical analysis of corrugated tube flow using RBFNs

This paper reports the application of neural networks for the numerical analysis of steady-state axisymmetric flow through an indefinitely long corrugated tube. Meshless global radial basis function networks (RBFNs) are employed to represent all dependent variables in the governing differential equations. For a better quality of approximation, the networks used here are constructed based on the integration process rather than the usual differentiation process. Multiple spaces of network weights for each variable are converted into the single space of nodal variable values, resulting in the square system of equations with usual size. The governing equations are discretized in the strong form by point collocation and the resultant nonlinear system is solved with trust-region methods. The corrugated tube flow of a Newtonian fluid, power-law fluid and Oldroyd-B fluid are considered. With relatively low numbers of data points, flow resistance predictions obtained are in good agreement with the benchmark solutions

Evidence from panel unit root and cointegration tests that the Environmental Kuznets Curve does not exist

The Environmental Kuznets Curve (EKC) hypothesis – an inverted U-shape relation between various indicators of environmental degradation and income per capita – has become one of the ‘stylised facts’ of environmental and resource economics. This is despite considerable criticism on both theoretical and empirical grounds. Cointegration analysis can be used to test the validity of such stylised facts when the data involved contain stochastic trends. In the present paper, we use cointegration analysis to test the EKC hypothesis using a panel dataset of sulfur emissions and GDP data for 74 countries over a span of 31 years. We find that the data is stochastically trending in the time-series dimension. Given this, and interpreting the EKC as a long run equilibrium relationship, support for the hypothesis requires that an appropriate model cointegrates and that sulfur emissions are a concave function of income. Individual and panel cointegration tests cast doubt on the general applicability of the hypothesised relationship. Even when we find cointegration, many of the relationships for individual countries are not concave. The results show that the EKC is a problematic concept, at least in the case of sulfur emissions.Environmental Economics and Policy,

Platform Pricing Structure and Moral Hazard

We study pricing by a monopoly platform that matches buyers and sellers in an environment with cross-market externalities. Said platform has no private information, does not set the commodity's price and can only charge trading parties for the transaction. Our innovation consists in introducing moral hazard on the sellers' side and an equilibrium notion of platform reputation in an infinite horizon model. With linear fees the platform can mitigate, but not eliminate, the loss of reputation induced by moral hazard. If lump-sum fees (registration fees) can be levied, moral hazard can be overcome. The upfront payment determines the participation threshold of sellers and extracts them, while (lower) transactions fees provide incentives for good behavior. This breaks the equivalence of lump-sum payments and linear fees (Rochet and Tirole (2006)). We draw implications for the role of subsidies (Caillaud and Jullien (2003)).Platforms; Two-Sided Markets; Reputation; Moral Hazard

SUPPLY AND DEMAND FOR MARRIED FEMALE LABOR: RURAL AND URBAN DIFFERENCES IN THE SOUTHERN UNITED STATES

This study examined the supply of and demand for married female labor in the southern United States. Special attention was given to differences in labor force participation, labor supply, and quantities of labor supplied and demanded across rural and urban areas. Once state effects were accounted for, decisions to change participation were found not to vary by urban-rural designation. Differences in demand were fully captured by an intercept shifter and the variations in hours supplied by married females between urban and rural areas. Labor supply varied greatly with the effects of key determinants (number of children, work force experience, family income) being strongly different in rural areas. Different policies are needed to promote female labor supply in rural areas as opposed to urban areas.Community/Rural/Urban Development, Labor and Human Capital,

Analysis of Texas Winery Visitor Spending and GOTEXAN Efforts to Promote Winery Tourism

Swinburne University (Langworthy, Howard, Fiona & Mawson, 2006), agri-tourism is a growing phenomenon in Australia, often most strongly associated with wine regions. Recommendations to improve include creation of tourism regions & cooperatives, cooperation between sectors (CVBs, restaurants), infrastructure development and model development to measurable factors. South African wineries Bruwer, 2003 identified factors that were helpful in developing a wine tourism market of South African wineries. Regarding South Africa wine tourism, areas of winery business that promote tourism include both service provision and destination marketing, development of wine routes forms an integral part of the wine tourism industry, estates sell more wine through the cellar-door and tourism industry needs well-developed infrastructure. To complete this analysis for Texas, an online survey was sent to over 9,000 wine consumers. Preliminary results of this study found that Texas winery travelers spend over $400 per winery visit. Winery tourism outspend typical tourist in Texas with 24% of their spending related to accommodations spending. Wineries involved in promoting tourism visitations have significantly higher sales and winery visitation than those not focusing on tourism as part of the marketing promotions (p<.05). A secondary aspect of this study is to survey Texas wineries and measure their involvement and satisfaction with TDA wine support efforts. The results illustrate that wineries involved in TDA wine promotional programs report higher increases in sales, winery visitations and attribute increases in sales to TDA marketing efforts over those less involved wineries.Texas Wine, TDA Wine Marketing, State Value of Wine Marketing, Wine Tourism, Rural Tourism, Tourism, Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Marketing,