Vijay K. Narayanan

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The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and non-luminous matter in the Universe: a photometrically and astrometrically calibrated digital imaging survey of π steradians above about Galactic latitude 30◦ in five broad optical bands to a depth of g′ ∼ 23, and a spectroscopic(More)
The explosion of online content has made the management of such content non-trivial. Web-related tasks such as web page categorization, news filtering, query categorization, tag recommendation, etc. often involve the construction of multi-label categorization systems on a large scale. Existing multi-label classification methods either do not scale or have(More)
The United Nations Framework Convention on Climate Change requires nations to implement measures for adapting to rising sea level and other effects of changing climate. To decide upon an appropriate response, coastal planners and engineers must weigh the cost of these measures against the likely cost of failing to prepare, which depends on the probability(More)
We describe the target selection and resulting properties of a spectroscopic sample of luminous, red galaxies (LRG) from the imaging data of the Sloan Digital Sky Survey (SDSS). These galaxies are selected on the basis of color and magnitude to yield a sample of luminous, intrinsically red galaxies that extends fainter and further than the main flux-limited(More)
Recent advances in high throughput data collection and storage technologies have led to a dramatic increase in the availability of high-resolution time series data sets in various domains. These time series reflect the dynamics of the underlying physical processes in these domains. Detecting changes in a time series over time or changes in the relationships(More)
We present the experiences from building a web-scale user modeling platform for optimizing display advertising targeting at Yahoo!. The platform described in this paper allows for per-campaign maximization of <i>conversions</i> representing purchase activities or transactions. Conversions directly translate to advertiser's revenue, and thus provide the most(More)
In the course of its commissioning observations, the Sloan Digital Sky Survey (SDSS) has produced one of the largest redshift samples of galaxies selected from CCD images. Using 11,275 galaxies complete to r∗ = 17.6 over 140 square degrees, we compute the luminosity function of galaxies in the r∗ band over a range −23 < Mr∗ < −16 (for h = 1). The result is(More)
We discuss the optical and radio properties of 30,000 FIRST (radio, 20 cm, sensitive to 1 mJy) sources positionally associated within 1>5 with a Sloan Digital Sky Survey (SDSS) (optical, sensitive to r* 22.2) source in 1230 deg2 of sky. The matched sample represents 30% of the 108,000 FIRST sources and 0.1% of the 2.5 107 SDSS sources in the studied region.(More)
The ubiquity of supermassive black holes (SMBHs) at the centers of nearby luminous galaxies can arise from the multiple mergers experienced by dark matter halos in hierarchical structure formation models, even if only a small fraction of these galaxies harbor SMBHs at high redshifts. We illustrate this possibility using cosmological Monte Carlo simulations(More)