18,287 research outputs found

    The Hidden Energy Cost of Web Advertising

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    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

    Linear LL-positive sets and their polar subspaces

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    In this paper, we define a Banach SNL space to be a Banach space with a certain kind of linear map from it into its dual, and we develop the theory of linear LL-positive subsets of Banach SNL spaces with Banach SNL dual spaces. We use this theory to give simplified proofs of some recent results of Bauschke, Borwein, Wang and Yao, and also of the classical Brezis-Browder theorem.Comment: 11 pages. Notational changes since version

    Spatiospectral concentration on a sphere

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    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

    Adaptive Reuse of Religious Buildings and Schools in the US: Determinants of Project Outcomes

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    This study addresses factors that affect the outcomes of adaptive reuse of empty religious buildings and schools in the United States. Literature-driven observable factors expected to have an impact on project outcomes include both supply side and demand side factors (building characteristics, neighborhood demographics, micro-location characteristics, macro-economic factors, etc.) are used as explanatory variables. This study uses the multinomial logit model with the outcome of adaptive reuse projects (e.g., apartments, condominiums, retail, office and cultural uses) as the dependent variable. This study has found that many supply side and demand side factors are associated with certain outcomes. It is expected that the results of this study can offer valuable basic information about associations between factors and development outcomes for adaptive reuse.Adaptive reuse; Multinomial logit model; Religious buildings and schools

    The Effect of School Quality on Residential Sales Price

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    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.

    Religious Value Halos: The Effect of a Jewish Orthodox Campus on Residential Property Values

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    Ten years ago, there was a controversial expansion of an Orthodox Jewish religious campus in the suburb of a large Midwestern US city. This research takes a before and after approach to addressing the effects of this project on residential property values, especially within walking distance of the campus. Separate regression analyses have been run for 1997 and 2006, and the findings indicate that the campus has increased property values and prompted additional building permits. The findings show that the completion of the Jewish Orthodox campus increases residential property values between 17 percent and 20 percent within a quarter mile in the city where the facility is located.

    Determining Off-Site Damages to Non-Residential Property from Leaking Underground Storage Tanks Using Contingent Valuation Analysis

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    This research evaluates the effect of leaking underground storage tanks (LUSTs) from gas stations on nearby commercial property when the existing data is incomplete or imperfect. While methodologies such as hedonic regression may be preferred for evaluating the effects of LUSTs on property values, the rigorous data requirements of these methodologies often cannot be met. Contingent valuation analysis is one method that enables estimation of losses when the data available is incomplete. A contingent valuation analysis of real estate professionals in South Carolina and Ohio provides estimates of commercial property losses, which ranges from 0-40%, depending on environmental conditions and proximity to the source. This research has developed a methodology for estimating real estate property value losses when data requirements cannot be fulfilled based on the best available data.Environmental contamination; Commercial property; Underground storage tanks; Contingent valuation analysis

    Fixed parameter tractability of crossing minimization of almost-trees

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    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

    Learning Visual Question Answering by Bootstrapping Hard Attention

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    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
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