Oscar Rojas

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Large search engines are complex systems composed by several services. Each service is composed by a set of distributed processing nodes dedicated to execute a single operation required to user queries. One of these services is in charge of computing the top-k document results for queries by means of a document ranking operation. This ranking service is a(More)
—Focused crawlers are programs designed to download web pages which are relevant to specific topics. Using information gathered at running time, focused crawlers explore the web following promissory hyperlinks and fetching only pages which appear to be relevant. These crawlers are receiving increasing attention because they favor the construction of(More)
OBJECTIVE To estimate the prevalence of adult attention deficit/hyperactivity disorder (ADHD) in a sample of cocaine-dependent patients, and to examine the discriminant validity of the Barkley's executive dysfunction scale in differentiating cocaine-dependent patients with and without ADHD. METHODS A cross-sectional design was used. A total of 166(More)
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