59 research outputs found
Relating Web pages to enable information-gathering tasks
We argue that relationships between Web pages are functions of the user's
intent. We identify a class of Web tasks - information-gathering - that can be
facilitated by a search engine that provides links to pages which are related
to the page the user is currently viewing. We define three kinds of intentional
relationships that correspond to whether the user is a) seeking sources of
information, b) reading pages which provide information, or c) surfing through
pages as part of an extended information-gathering process. We show that these
three relationships can be productively mined using a combination of textual
and link information and provide three scoring mechanisms that correspond to
them: {\em SeekRel}, {\em FactRel} and {\em SurfRel}. These scoring mechanisms
incorporate both textual and link information. We build a set of capacitated
subnetworks - each corresponding to a particular keyword - that mirror the
interconnection structure of the World Wide Web. The scores are computed by
computing flows on these subnetworks. The capacities of the links are derived
from the {\em hub} and {\em authority} values of the nodes they connect,
following the work of Kleinberg (1998) on assigning authority to pages in
hyperlinked environments. We evaluated our scoring mechanism by running
experiments on four data sets taken from the Web. We present user evaluations
of the relevance of the top results returned by our scoring mechanisms and
compare those to the top results returned by Google's Similar Pages feature,
and the {\em Companion} algorithm proposed by Dean and Henzinger (1999).Comment: In Proceedings of ACM Hypertext 200
Deterministic Sampling and Range Counting in Geometric Data Streams
We present memory-efficient deterministic algorithms for constructing
epsilon-nets and epsilon-approximations of streams of geometric data. Unlike
probabilistic approaches, these deterministic samples provide guaranteed bounds
on their approximation factors. We show how our deterministic samples can be
used to answer approximate online iceberg geometric queries on data streams. We
use these techniques to approximate several robust statistics of geometric data
streams, including Tukey depth, simplicial depth, regression depth, the
Thiel-Sen estimator, and the least median of squares. Our algorithms use only a
polylogarithmic amount of memory, provided the desired approximation factors
are inverse-polylogarithmic. We also include a lower bound for non-iceberg
geometric queries.Comment: 12 pages, 1 figur
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