Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Can Smartphone Co-locations Detect Friendship? It Depends How You Model
  It   We present a study to detect friendship, its strength, and its change from
smartphone location data collectedamong members of a fraternity. We extract a
rich set of co-location features and build classifiers that detectfriendships
and close friendship at 30% above a random baseline. We design cross-validation
schema to testour model performance in specific application settings, finding
it robust to seeing new dyads and to temporalvariance.

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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
3
The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol