title: Automatic end-to-end De-identification: Is high accuracy the only metric?

authors: Yogarajan, Vithya

subjects: automatic de-identification

abstract: De-identification of electronic health records (EHR) is a vital step towards advancing health informatics research and maximising the use of available data. It is a two-step process where step one is the identification of protected health information (PHI), and step two is replacing such PHI with surrogates. Despite the recent advances in automatic de-identification of EHR, significant obstacles remain if the abundant health data available are to be used to the full potential. Accuracy in de-identification could be considered a necessary, but not sufficient condition for the use of EHR without individual patient consent. We present here a comprehensive review of the progress to date, both the impressive successes in achieving high accuracy and the significant risks and challenges that remain. To best of our knowledge, this is the first paper to present a complete picture of end-to-end automatic de-identification. We review 18 recently published automatic de-identification systems -designed to de-identify EHR in the form of free text- to show the advancements made in improving the overall accuracy of the system, and in identifying individual PHI. We argue that despite the improvements in accuracy there remain challenges in surrogate generation and replacements of identified PHIs, and the risks posed to patient protection and privacy.

text: Automatic end-to-end De-identification: Is high accuracy the only metric? De-identification of electronic health records (EHR) is a vital step towards advancing health informatics research and maximising the use of available data. It is a two-step process where step one is the identification of protected health information (PHI), and step two is replacing such PHI with surrogates. Despite the recent advances in automatic de-identification of EHR, significant obstacles remain if the abundant health data available are to be used to the full potential. Accuracy in de-identification could be considered a necessary, but not sufficient condition for the use of EHR without individual patient consent. We present here a comprehensive review of the progress to date, both the impressive successes in achieving high accuracy and the significant risks and challenges that remain. To best of our knowledge, this is the first paper to present a complete picture of end-to-end automatic de-identification. We review 18 recently published automatic de-identification systems -designed to de-identify EHR in the form of free text- to show the advancements made in improving the overall accuracy of the system, and in identifying individual PHI. We argue that despite the improvements in accuracy there remain challenges in surrogate generation and replacements of identified PHIs, and the risks posed to patient protection and privacy.

year: 2019

title: Indeterminacy and instability in Petschek reconnection

authors: Forbes, Terry G.

subjects: magnetic reconnection

abstract: We explain two puzzling aspects of Petschek's model for fast reconnection. One is its failure to occur in plasma simulations with uniform resistivity. The other is its inability to provide anything more than an upper limit for the reconnection rate. We have found that previously published analytical solutions based on Petschek's model are structurally unstable if the electrical resistivity is uniform. The structural instability is associated with the presence of an essential singularity at the X-line that is unphysical. By requiring that such a singularity does not exist, we obtain a formula that predicts a specific rate of reconnection. For uniform resistivity, reconnection can only occur at the slow, Sweet-Parker rate. For nonuniform resistivity, reconnection can occur at a much faster rate provided that the resistivity profile is not too flat near the X-line. If this condition is satisfied, then the scale length of the nonuniformity determines the reconnection rate.

text: Indeterminacy and instability in Petschek reconnection We explain two puzzling aspects of Petschek's model for fast reconnection. One is its failure to occur in plasma simulations with uniform resistivity. The other is its inability to provide anything more than an upper limit for the reconnection rate. We have found that previously published analytical solutions based on Petschek's model are structurally unstable if the electrical resistivity is uniform. The structural instability is associated with the presence of an essential singularity at the X-line that is unphysical. By requiring that such a singularity does not exist, we obtain a formula that predicts a specific rate of reconnection. For uniform resistivity, reconnection can only occur at the slow, Sweet-Parker rate. For nonuniform resistivity, reconnection can occur at a much faster rate provided that the resistivity profile is not too flat near the X-line. If this condition is satisfied, then the scale length of the nonuniformity determines the reconnection rate.

year: 2013

title: When loanwords are not lone words: Using networks and hypergraphs to explore Māori loanwords in New Zealand English

authors: Trye, David

abstract: Networks are being used to model an increasingly diverse range of realworld phenomena. This paper introduces an exploratory approach to studying loanwords in relation to one another, using networks of co-occurrence. While traditional studies treat individual loanwords as discrete items, we show that insights can be gained by focusing on the various loanwords that co-occur within each text in a corpus, especially when leveraging the notion of a hypergraph. Our research involves a case-study of New Zealand English (NZE), which borrows Indigenous Māori words on a large scale. We use a topic-constrained corpus to show that: (i) Māori loanword types tend not to occur by themselves in a text; (ii) infrequent loanwords are nearly always accompanied by frequent loanwords; and (iii) it is not uncommon for texts to contain a mixture of listed and unlisted loanwords, suggesting that NZE is still riding a wave of borrowing importation from Māori.

text: When loanwords are not lone words: Using networks and hypergraphs to explore Māori loanwords in New Zealand English Networks are being used to model an increasingly diverse range of realworld phenomena. This paper introduces an exploratory approach to studying loanwords in relation to one another, using networks of co-occurrence. While traditional studies treat individual loanwords as discrete items, we show that insights can be gained by focusing on the various loanwords that co-occur within each text in a corpus, especially when leveraging the notion of a hypergraph. Our research involves a case-study of New Zealand English (NZE), which borrows Indigenous Māori words on a large scale. We use a topic-constrained corpus to show that: (i) Māori loanword types tend not to occur by themselves in a text; (ii) infrequent loanwords are nearly always accompanied by frequent loanwords; and (iii) it is not uncommon for texts to contain a mixture of listed and unlisted loanwords, suggesting that NZE is still riding a wave of borrowing importation from Māori.

year: 2023