Privacy-preserving record linkage using Bloom filters

<p>Abstract</p> <p>Background</p> <p>Combining multiple databases with disjunctive or additional information on the same person is occurring increasingly throughout research. If unique identification numbers for these individuals are not available, probabilistic record linkage is used for the identification of matching record pairs. In many applications, identifiers have to be encrypted due to privacy concerns.</p> <p>Methods</p> <p>A new protocol for privacy-preserving record linkage with encrypted identifiers allowing for errors in identifiers has been developed. The protocol is based on Bloom filters on <it>q</it>-grams of identifiers.</p> <p>Results</p> <p>Tests on simulated and actual databases yield linkage results comparable to non-encrypted identifiers and superior to results from phonetic encodings.</p> <p>Conclusion</p> <p>We proposed a protocol for privacy-preserving record linkage with encrypted identifiers allowing for errors in identifiers. Since the protocol can be easily enhanced and has a low computational burden, the protocol might be useful for many applications requiring privacy-preserving record linkage.</p

MTB: ein Record-Linkage-Programm für die empirische Sozialforschung

"In der Praxis der empirischen Sozialforschung werden häufig Datensätze aus verschiedenen Datenquellen zusammengeführt (Record-Linkage). Solange in unterschiedlichen Datenquellen gemeinsame fehlerfreie Schlüssel (z.B. Namen oder Matrikelnummern) existieren, ist die Zusammenführung problemlos. Fehler in den gemeinsamen Schlüsseln erzwingen fast immer aufwändige manuelle Korrekturen. Um die Zusammenführung unterschiedlicher Datenbestände trotz fehlerhafter Schlüssel zu ermöglichen, wurde im Rahmen eines DFG-Projekts ein Computerprogramm entwickelt, um diese Aufgabe zu erleichtern: Die 'Merge-Toolbox', kurz: 'MTB'." (Autorenreferat)"Bringing together data files from different sources (record linkage) is a common task in social science. As long as the data files contain clean merging keys (e.g. names or identification numbers) the procedure is rather trivial. However, if the merging keys are error prone, manual corrections are inevitable. To facilitate record linkage using error prone keys we developed the computer programme 'Merge Toolbox' (MTB) within the scope of the DFG-funded research project 'Record linkage using error prone strings'." (author's abstract

Entwicklung einer neuen fehlertoleranten Methode bei der Verknüpfung von personenbezogenen Datenbanken unter Gewährleistung des Datenschutzes

"Die Verknüpfung der Angaben mehrerer Datenbanken über dieselbe Person wird immer häufiger für Forschungszwecke genutzt. Aus Datenschutzgründen müssen die Identifikatoren in vielen Fällen vor der Zusammenführung verschlüsselt werden. Bisher verwendete Techniken sind hierbei ineffizient, da Fälle mit Fehlern in den Identifikatoren fast immer vollständig verloren gehen. Die Autoren haben ein neues Verfahren entwickelt, das trotz starker Verschlüsselung Fehler in den Identifikatoren toleriert. Testergebnisse anhand simulierter und echter Datenbestände zeigen, dass das Verfahren ähnlich gute Ergebnisse erbringt wie unverschlüsselte Identifikatoren. Das Verfahren kann für viele Probleme in der Forschungspraxis der empirischen Sozialforschung verwendet werden." (Autorenreferat)"Combining multiple databases with additional information on the same person is increasingly occurring throughout research. In many applications, identifiers have to be encrypted due to privacy concerns. Existing protocols are inefficient in actual research practice since cases with errors in identifiers are almost always in their entirety lost. Therefore, a new protocol for privacy-preserving record linkage with encrypted identifiers allowing for errors in identifiers has been developed by the authors. The results from tests on simulated and actual databases are comparable to non-encrypted identifiers. This new technique will have many practical applications in social research." (author's abstract

Die Anwendung statistischer Record-Linkage-Methoden auf selbst-generierte Codes bei Längsschnitterhebungen

'Bei wiederholten Befragungen zu sensitiven Themen werden häufig von den Befragten selbst-generierte Codes zur Zusammenführung der Daten über die Wellen hinweg verwendet. Dabei ist aufgrund fehlerhafter Daten der Verlust an Fällen in der Regel beträchtlich. Um den Prozess der Zusammenführung zu beschleunigen und die Zahl verlorener Fälle zu minimieren wird hier die Nutzung automatisierter Record-Linkage-Techniken vorgeschlagen. Bei zwei Simulationsstudien und in einer praktischen Anwendung zeigen sich Techniken des Record-Linkage der bisher verwendeten manuellen Methode überlegen. Die Experimente legen bei Verwendung dieser Techniken den Einsatz deutlich längerer Codes als bisher üblich nahe.' (Autorenreferat)'Panel studies on sensitive topics usually apply respondent generated codes to link records across surveys. This implies a substantial loss of cases due to errors in the codes. In order to speed up the process of linking and minimizing the number of losses due to errors, the authors propose the application of automatic record-linkage procedures. In two simulations and a real-world application, the record-linkage procedures outperformed the manual procedure. The experiments suggest the use of longer self-generated codes for record-linkage applications.' (author's abstract)

Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

Peptidomics of the Agriculturally Damaging Larval Stage of the Cabbage Root Fly Delia radicum (Diptera: Anthomyiidae)

The larvae of the cabbage root fly induce serious damage to cultivated crops of the family Brassicaceae. We here report the biochemical characterisation of neuropeptides from the central nervous system and neurohemal organs, as well as regulatory peptides from enteroendocrine midgut cells of the cabbage maggot. By LC-MALDI-TOF/TOF and chemical labelling with 4-sulfophenyl isothiocyanate, 38 peptides could be identified, representing major insect peptide families: allatostatin A, allatostatin C, FMRFamide-like peptides, kinin, CAPA peptides, pyrokinins, sNPF, myosuppressin, corazonin, SIFamide, sulfakinins, tachykinins, NPLP1-peptides, adipokinetic hormone and CCHamide 1. We also report a new peptide (Yamide) which appears to be homolog to an amidated eclosion hormone-associated peptide in several Drosophila species. Immunocytochemical characterisation of the distribution of several classes of peptide-immunoreactive neurons and enteroendocrine cells shows a very similar but not identical peptide distribution to Drosophila. Since peptides regulate many vital physiological and behavioural processes such as moulting or feeding, our data may initiate the pharmacological testing and development of new specific peptide-based protection methods against the cabbage root fly and its larva

Peptidomics and processing of regulatory peptides in the fruit fly Drosophila

More than a decade has passed since the release of the Drosophila melanogaster genome and the first predictions of fruit fly regulatory peptides (neuropeptides and peptide hormones). Since then, mass spectrometry-based methods have fuelled the chemical characterisation of regulatory peptides, from 7 Drosophila peptides in the pre-genomic area to more than 60 today. We review the development of fruit fly peptidomics, and present a comprehensive list of the regulatory peptides that have been chemically characterised until today. We also summarise the knowledge on peptide processing in Drosophila, which has strongly profited from a combination of MS-based techniques and the genetic tools available for the fruit fly. This combination has a very high potential to study the functional biology of peptide signalling on all levels, especially with the ongoing developments in quantitative MS in Drosophila

A new Name-Based Sampling Method for Migrants using n-grams

The set of best methods for sampling migrant populations includes name-based sampling. So far this is done using either ad hoc lists or onomastic dictionaries for the classification of names. This paper proposes a new name-based procedure which uses a Bayes-classifier for the n-grams of the name. The new procedure is fault-tolerant of alternate spellings, and also allows the classification of names that are not found in dictionaries. It was tested using the names of about 1.600 foreigners in the PASS panel. Finally, a CATI survey based on the new method in Hesse (Germany) is described

A New Name-Based Sampling Method for Migrants

Zu den besten Verfahren für die Konstruktion von Migrantenstichproben gehören namensbasierte Stichproben. Hierfür werden bislang entweder ad-hoc-Listen oder namenskundliche Lexika für die Klassifikation von Namen verwendet. In diesem Beitrag wird ein neues Verfahren vorgeschlagen, das auf der automatischen Klassifikation eines Namens anhand der n-Gramme des Namens und der Anwendung des Bayes-Theorems basiert. Das neue Verfahren ist fehlertolerant gegenüber alternativen Schreibweisen und erlaubt auch die Klassifikation von Namen, die sich nicht in den Lexika finden. Das Verfahren wurde anhand der Namen der ca. 1.600 Ausländer im PASS-Panel und einer CATI-Studie in Hessen untersucht