Wednesday, 25 March 2015

Overview of the NILM field

This post aims to use trends in recent publications to provide an overview of the field of non-intrusive load monitoring / energy disaggregation.

Recent Growth


Researchers often refer to a recent explosion in the number of NILM publications. The graph below shows the number of papers published per year, from which the upward trend since 2010 is clearly visible. This renewed interest is likely due to recent country-wide roll outs of smart meters.


Significant Publications


In such a rapidly growing field, it's often hard to understand which publications are the most significant. The graph below shows the number of citations of the most cited papers. Unsurprisingly, Hart's 1992 seminal paper is the most cited by far, with a number of other papers from the 90s also appearing high up the list.


Since older papers have had more time to accumulate citations, it's also interesting to look at citations per year to get a better idea of recent trends in the field, as shown by the graph below. Unlike before, there is no stand-out paper, with recent review papers and data set papers receiving the greatest citation velocity. Besides these papers, a number of the remaining highly cited papers propose techniques based upon principled machine learning models.


Publishers


I am often asked which are the most popular venues for NILM research. The graph below shows the most popular publishers, with ieeexplore clearly publishing the most papers in this field. Unfortunately, I couldn't get hold of high quality data for conferences/journals, which I'm sure would have been useful.


Keywords


Finally, it's also interesting to analyse common keywords in existing publications. The graph below shows the most commonly occurring words in paper titles, with words such as 'a' and 'the' omitted. Besides the obvious terms such as 'nonintrusive', 'appliance', 'load', 'monitoring', 'energy' and 'disaggregation', other interesting terms pop up, such as 'smart', 'identification', 'residential' and 'home'.


Update 12.09.2016: cleaned up graph appearance.
Update 12.09.2016: added data and notebook used to generate these graphs to the nilm-papers github repository.

3 comments:

  1. How did you do this analysis can you share the knowledge.

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    Replies
    1. I used Publish or Perish (http://www.harzing.com/resources/publish-or-perish) to download a CSV of publications which cite Hart's 1992 paper, and then produced the graphs using python and pandas.

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    2. I've just added the data and notebook I used to generate these graphs to github: https://github.com/oliparson/nilm-papers

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