Lovelace, R and Ballas, D (2013) `Truncate, replicate, sample': A new approach to the `integerisation' of weights for spatial microsimulation. Computers Environment and Urban Systems, 41. pp. 1-11.
Abstract
Iterative proportional fitting (IPF) is a widely used method for spatial microsimulation. The technique results in non-integer weights for individual rows of data. This is problematic for certain applications and has led many researchers to favour combinatorial optimisation approaches such as simulated annealing. An alternative to this is ‘integerisation’ of IPF weights: the translation of the continuous weight variable into a discrete number of unique or ‘cloned’ individuals. We describe four existing methods of integerisation and present a new one. Our method – ‘truncate, replicate, sample’ (TRS) – recognises that IPF weights consist of both ‘replication weights’ and ‘conventional weights’, the effects of which need to be separated. The procedure consists of three steps: (1) separate replication and conventional weights by truncation; (2) replication of individuals with positive integer weights; and (3) probabilistic sampling The results, which are reproducible using supplementary code and data published alongside this paper, show that TRS is fast, and more accurate than alternative approaches to integerisation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2013 Elsevier. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Microsimulation, integerisation, iterative proportional fitting |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield) |
Funding Information: | Funder Grant number EPSRC EP/G037477/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 22 Aug 2013 07:39 |
Last Modified: | 22 Aug 2013 07:39 |
Published Version: | http://www.sciencedirect.com/science/article/pii/S... |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.compenvurbsys.2013.03.004 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:76294 |