2,019 research outputs found

    Thermal modeling of Anchorage driveway culvert with addition of insulation to prevent frost heaving

    Get PDF
    A predominate problem in cold regions, and specifically in Anchorage, Alaska, is frost heaving pavement above culverts in residential driveways. The culvert increases heat loss in the subgrade materials during winter months and allows the soils below the culvert to freeze, which is not an issue if the underlying soils are non-frost susceptible material. However, there are numerous locations in Anchorage and other parts of Alaska where the underlying soils are frost susceptible which result in frost heaving culverts under driveways that cause damaged pavement and culvert inverts that are too high. The seasonal heave and settlement of culverts under driveways accelerates pavement deterioration. A model of this scenario was developed and several insulation configurations were considered to determine a suitable alternative for preventing pavement damage from heaving culverts. The model used material properties for typical Anchorage area silty sand. The model showed that insulation could be used below culverts to prevent differential frost heave at the culvert. In addition, this technique uses typical construction materials and is reasonable for a typical residential dwelling contractor to complete during the construction of the home.Title Page / Abstract / Table of Contents / List of Figures / List of Tables / Introduction / Literature Review / Driveway Pavement Section / Driveway Pavement Section Design Method / Driveway Pavement Section / Thermal Analysis / TEMP/W (GeoStudio 2012) / Model Configuration / Model Materials and Boundary Conditions / Analysis Procedure / Results / Steady State Model and Temperature Gradient / Thermal Analysis with Pavement and Culvert without Insulation / Thermal Analysis with Pavement, Culvert, and Insulation / Discussion / Conclusions / Recommendations / References / Appendi

    Repeated sequences in linear genetic programming genomes

    Get PDF
    Biological chromosomes are replete with repetitive sequences, micro satellites, SSR tracts, ALU, etc. in their DNA base sequences. We started looking for similar phenomena in evolutionary computation. First studies find copious repeated sequences, which can be hierarchically decomposed into shorter sequences, in programs evolved using both homologous and two point crossover but not with headless chicken crossover or other mutations. In bloated programs the small number of effective or expressed instructions appear in both repeated and nonrepeated code. Hinting that building-blocks or code reuse may evolve in unplanned ways. Mackey-Glass chaotic time series prediction and eukaryotic protein localisation (both previously used as artificial intelligence machine learning benchmarks) demonstrate evolution of Shannon information (entropy) and lead to models capable of lossy Kolmogorov compression. Our findings with diverse benchmarks and GP systems suggest this emergent phenomenon may be widespread in genetic systems

    Repeated patterns in tree genetic programming

    Get PDF
    We extend our analysis of repetitive patterns found in genetic programming genomes to tree based GP. As in linear GP, repetitive patterns are present in large numbers. Size fair crossover limits bloat in automatic programming, preventing the evolution of recurring motifs. We examine these complex properties in detail: e.g. using depth v. size Catalan binary tree shape plots, subgraph and subtree matching, information entropy, syntactic and semantic fitness correlations and diffuse introns. We relate this emergent phenomenon to considerations about building blocks in GP and how GP works

    Green Price Indices

    Get PDF
    This paper suggests two theoretically consistent and empirically tractable ways that a cost-ofliving index can be expanded to include the environment and other public goods. In addition, it presents an empirical illustration of such an index for Los Angeles, California, incorporating air quality and other spatially varying public goods using a hedonic model. The results indicate that the required information can be recovered and that including public goods can make a noticeable difference in the index.air quality, green accounting, hedonic regression, nonmarket valuation, price index

    Moving Beyond Cleanup: Identifying the Crucibles of Environmental Gentrification

    Get PDF
    This paper reviews the distributional impacts associated with "environmental gentrification" following the cleanup and reuse of LULUs. By making a neighborhood more attractive, cleanup and reuse of LULUs may drive up local real estate prices. Renters in the neighborhood would have to pay higher rents. Moreover, existing residents may not value the removal of the disamenity as much as other households, creating a mismatch between their priorities and the new character of the neighborhood. Thus, even if they do not move, existing residents, especially renters, may be harmed by the gentrification effects of cleanup. We find that even a simple economic model does not yield clear predictions on neighborhood effects following cleanup, except for the initial effect of rising housing values. In the empirical literature, we actually find conflicting evidence of rising real estate prices following cleanup of LULUs. We find somewhat stronger evidence for increased housing density and increasing incomes, but no evidence for racial impacts. Our review also uncovers a variety of factors that are likely to minimize the likelihood of gentrification or temper its adverse consequences. Working Paper 07-2

    The Architecture and Measurement of an Ecosystem Services Index

    Get PDF
    This paper describes the construction of an ecological services index (ESI). An ESI is meant to summarize and track over time the magnitude of beneficial services arising from the natural environment. A central task of this paper is to define rigorously ecosystem services so that services can be counted in an economically and ecologically defensible manner—a requirement if ecological contributions to welfare are to be incorporated into the national accounts. This paper advocates a particular economic structure and relates it to index theory and makes concrete recommendations for the measurement of such an index.ecosystem services, Green GDP, index numbers, ecological economics
    corecore