The Effect of School Quality on Residential Sales Price

This study seeks to find the extent to which various measures of public school quality are capitalized into house prices after the No Child Left Behind Act (2001). Individual residential sales in Cuyahoga County, Ohio for 2000 and 2005 are analyzed as to the effect of school quality using regression analysis with a spatial error model. Results show that while all school quality measures tested have some explanatory power, school district ratings and performance index, which are comprehensive measures of school quality, are the most appropriate measures and are readily capitalized into housing prices.

The Hidden Energy Cost of Web Advertising

Advertising is an important source of income for many websites. To get the attention of the unsuspecting (and probably uninterested) visitors, web advertisements (ads) tend to use elaborate animations and graphics. Depending on the specific technology being used, displaying such ads on the visitor's screen may require a vast amount of CPU-power. Since present day desktop-CPUs can easily use 100W or more, ads may consume a substantial amount of energy. Although it is important for environmental reasons to reduce energy consumption, increasing the number of ads seems to be counterproductive.\ud The goal of this paper is to investigate the power consumption of web advertisements. For this purpose we used an energy meter to measure the differences in PC power consumption while browsing the web normally (thus with ads enabled), and while browsing with ads being blocked.\ud To simulate normal web browsing, we created a browser-based tool called AutoBrowse, which periodically opens an URL from a predefined list. To block advertisements, we used the Adblock Plus extension for Mozilla Firefox. To measure also power consumption with other browsers, we used in addition the Apache HTTP server and its mod_proxy module to act as an ad-blocking proxy server.\ud The measurements on several PCs and browsers show that, on average, the additional energy consumption to display web advertisements is 2.5W. To put this number into perspective, we calculated that the total amount of energy used to display web advertisement is equivalent of the total yearly electricity consumption of nearly 2000 households in the Netherlands. It takes 3,6 “average” wind turbines to generate this amount of energy

Spatiospectral concentration on a sphere

We pose and solve the analogue of Slepian's time-frequency concentration problem on the surface of the unit sphere to determine an orthogonal family of strictly bandlimited functions that are optimally concentrated within a closed region of the sphere, or, alternatively, of strictly spacelimited functions that are optimally concentrated within the spherical harmonic domain. Such a basis of simultaneously spatially and spectrally concentrated functions should be a useful data analysis and representation tool in a variety of geophysical and planetary applications, as well as in medical imaging, computer science, cosmology and numerical analysis. The spherical Slepian functions can be found either by solving an algebraic eigenvalue problem in the spectral domain or by solving a Fredholm integral equation in the spatial domain. The associated eigenvalues are a measure of the spatiospectral concentration. When the concentration region is an axisymmetric polar cap the spatiospectral projection operator commutes with a Sturm-Liouville operator; this enables the eigenfunctions to be computed extremely accurately and efficiently, even when their area-bandwidth product, or Shannon number, is large. In the asymptotic limit of a small concentration region and a large spherical harmonic bandwidth the spherical concentration problem approaches its planar equivalent, which exhibits self-similarity when the Shannon number is kept invariant.Comment: 48 pages, 17 figures. Submitted to SIAM Review, August 24th, 200

Learning Visual Question Answering by Bootstrapping Hard Attention

Attention mechanisms in biological perception are thought to select subsets of perceptual information for more sophisticated processing which would be prohibitive to perform on all sensory inputs. In computer vision, however, there has been relatively little exploration of hard attention, where some information is selectively ignored, in spite of the success of soft attention, where information is re-weighted and aggregated, but never filtered out. Here, we introduce a new approach for hard attention and find it achieves very competitive performance on a recently-released visual question answering datasets, equalling and in some cases surpassing similar soft attention architectures while entirely ignoring some features. Even though the hard attention mechanism is thought to be non-differentiable, we found that the feature magnitudes correlate with semantic relevance, and provide a useful signal for our mechanism's attentional selection criterion. Because hard attention selects important features of the input information, it can also be more efficient than analogous soft attention mechanisms. This is especially important for recent approaches that use non-local pairwise operations, whereby computational and memory costs are quadratic in the size of the set of features.Comment: ECCV 201

Determining Market Perceptions on Contamination of Residential Property Buyers using Contingent Valuation Surveys

This study reports on the results of several residential contingent valuation (CV) studies conducted throughout the US. Over the past several years CV has often been used to illustrate potential residential buyer bid prices for contaminated real property. The data set for this study contains 1,115 telephone interviews and examines the consistency of the results for residential property affected by a Leaking Underground Storage Tank (LUST) in different markets in eight states, controlling for income, age, education, local market type, and other demographic factors. Negative discounts associated with a LUST for marginal bidders in the top half of the market were quite consistent across states, varying from ?25% to ?33%, with an average of ?31%,. Using ANOVA indicates that bidding patterns from six of the seven states were statistically similar. Male bidders, those over 40 years of age and those with no high school degree were more likely to bid, while those with higher incomes and those bidding on certain, rather than suspected contamination, were less likely to bid. Local market type did not appear to affect bid outcomes. Using the marginal bidder approach, the CV results benchmark reasonably closely to, but still higher than, revealed preference outcomes for residential LUST sites in Ohio.

A Meta-Analysis of the Effect of Environmental Contamination and Positive Amenities on Residential Real Estate Values

This paper addresses the effects of environmental contamination and positive amenities on proximate residential real estate property values in the United States. Contamination sources include leaking underground storage tanks, superfund sites, landfills, water and air pollution, power lines, pipeline ruptures, nuclear power plants, animal feedlots and several other urban nuisance uses. The study summarizes a literature review of 75 peer-reviewed journal articles and selected case studies, and generates a data set of about 290 observations that contain information about each study’s loss (the dependent variable), with the independent variables being distance from the source, type of contamination, urban or rural environment, geographic region, market conditions and several other variables. Ordinary least squares is used to determine the effect of the contamination variables on reduction in property value. Broad contamination types, amenities, selected economic regions, distance from the source, information, research method and several other variables are statistically significant.

Fixed parameter tractability of crossing minimization of almost-trees

We investigate exact crossing minimization for graphs that differ from trees by a small number of additional edges, for several variants of the crossing minimization problem. In particular, we provide fixed parameter tractable algorithms for the 1-page book crossing number, the 2-page book crossing number, and the minimum number of crossed edges in 1-page and 2-page book drawings.Comment: Graph Drawing 201

Universal Spectral Correlation between Hamiltonians with Disorder

We study the correlation between the energy spectra of two disordered Hamiltonians of the form $H_a=H_{0a}+s_{a}\varphi$ ($a=1,2$) with $H_{0a}$ and $\varphi$ drawn from random distributions. We calculate this correlation function explicitly and show that it has a simple universal form for a broad class of random distributions.Comment: 9 pages, Jnl.tex Version 0.3 (version taken from the bulletin board), NSF-ITP-93-13