Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Privacy Assessment of De-identified Opal Data: A report for Transport
  for NSW   We consider the privacy implications of public release of a de-identified
dataset of Opal card transactions. The data was recently published at
https://opendata.transport.nsw.gov.au/dataset/opal-tap-on-and-tap-off. It
consists of tap-on and tap-off counts for NSW's four modes of public transport,
collected over two separate week-long periods. The data has been further
treated to improve privacy by removing small counts, aggregating some stops and
routes, and perturbing the counts. This is a summary of our findings.

18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys