3,285 research outputs found

    Using different groups of technological progress as input for sector modeling

    Get PDF
    This poster aims at describing different groups of technology use within a farm population and at delivering realistic prognoses of their future status as input for sector modeling. This because sector models are in many cases not based on reasonable technological progress estimations or too simplified as normative estimation or seen as mere extrapolation of past evolutions. The classification and utilization of technology groups is done for livestock activities, but illustrated hereafter for the finishing pigs activities. The research is worked out in three phases: • Organizational aspects of tuning information demand and supply; • Identification of technology groups; • Evolution of technology groups. Following techniques are used to identify the technology groups: Stochastic frontier analysis, cluster analysis and others. The results can be used in sector models to measure the impact of induced innovation on different technology groups.technology, sector modeling, induced innovation, Resource /Energy Economics and Policy,

    Self-consistent equation for an interacting Bose gas

    Full text link
    We consider interacting Bose gas in thermal equilibrium assuming a positive and bounded pair potential V(r)V(r) such that 0<\int d\br V(r) = a<\infty. Expressing the partition function by the Feynman-Kac functional integral yields a classical-like polymer representation of the quantum gas. With Mayer graph summation techniques, we demonstrate the existence of a self-consistent relation ρ(μ)=F(μaρ(μ))\rho (\mu)=F(\mu-a\rho(\mu)) between the density ρ\rho and the chemical potential μ\mu, valid in the range of convergence of Mayer series. The function FF is equal to the sum of all rooted multiply connected graphs. Using Kac's scaling V_{\gamma}(\br)=\gamma^{3}V(\gamma r) we prove that in the mean-field limit γ0\gamma\to 0 only tree diagrams contribute and function FF reduces to the free gas density. We also investigate how to extend the validity of the self-consistent relation beyond the convergence radius of Mayer series (vicinity of Bose-Einstein condensation) and study dominant corrections to mean field. At lowest order, the form of function FF is shown to depend on single polymer partition function for which we derive lower and upper bounds and on the resummation of ring diagrams which can be analytically performed.Comment: 33 pages, 6 figures, submitted to Phys.Rev.

    Shopping centre siting and modal choice in Belgium: a destination based analysis

    Get PDF
    Although modal split is only one of the elements considered in decision-making on new shopping malls, it remarkably often arises in arguments of both proponents and opponents. Today, this is also the case in the debate on the planned development of three major shopping malls in Belgium. Inspired by such debates, the present study focuses on the impact of the location of shopping centres on the travel mode choice of the customers. Our hypothesis is that destination-based variables such as embeddedness in the urban fabric, accessibility and mall size influence the travel mode choice of the visitors. Based on modal split data and location characteristics of seventeen existing shopping centres in Belgium, we develop a model for a more sustainable siting policy. The results show a major influence of the location of the shopping centre in relation to the urban form, and of the size of the mall. Shopping centres that are part of a dense urban fabric, measured through population density, are less car dependent. Smaller sites will attract more cyclists and pedestrians. Interestingly, our results deviate significantly from the figures that have been put forward in public debates on the shopping mall issue in Belgium
    corecore