Bitstring Processing for Statistical Evaluation of Large Volumes of Medical Data

Selbmann, H. K.

doi:10.1055/s-0038-1636134

Cited by 6 publications

(4 citation statements)

References 1 publication

(2 reference statements)

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“…if a = # then "if the query is unanswerable, swap El and EZ" 15. COUNT( 2') is posed (EI and EZ may require swapping in order that COUNT(T) be answerable).…”

Section: Constructing a Trackermentioning

confidence: 99%

A fast procedure for finding a tracker in a statistical database

Denning

Schlörer²

1980

ACM Trans. Database Syst.

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To avoid trivial compromises, most on-line statistical databases refuse to answer queries for statistics about small subgroups. Previous research discovered a powerful snooping tool, the tracker, with which the answers to these unanswerable queries are easily calculated. However, the extent of this threat was not clear, for no one had shown that finding a tracker is guaranteed to be easy. This paper gives a simple algorithm for tInding a tracker when the maximum number of identical records is not too large. The number of queries required to find a tracker is at most O(log$) queries, where S is the number of distinct records possible. Experimental results show that the procedure often finds a tracker with just a few queries. The threat posed by trackers is therefore considerable.

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“…if a = # then "if the query is unanswerable, swap El and EZ" 15. COUNT( 2') is posed (EI and EZ may require swapping in order that COUNT(T) be answerable).…”

Section: Constructing a Trackermentioning

confidence: 99%

A fast procedure for finding a tracker in a statistical database

Denning

Schlörer²

1980

ACM Trans. Database Syst.

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“…Because of Yz, Zi, and ZZ, the target conditions q (2'1) and q ( Tz) may differ strongly. This makes detection of the use of individual trackers difficult, especially if the system allows storage and arbitrary further use of definable record sets (e.g., [28,29]), so that q( TI), q( Tz), and q(C) (see (9.1)) can be entered at different times. Practical methods of constructing suitable pairs { TI, Tz} are described in [22, 251. For a permitted individual tracker the query q(C) from (9.1) is permitted, regardless of whether record X contains u+; in both cases k 5 1 C 1 % n -k. THEOREM 3.…”

Section: Individual Trackersmentioning

confidence: 99%

“…Traditionally, statistics were released off-line in the form of tables giving information about subsets of records defined using logical AND. Recently, the computer has made available flexible interactive statistical evaluation programs, offering all logical operations, including AND, OR, and NOT, for definition of record sets (e.g., [28,291). This paper is concerned with the threat of trackers and related disclosure techniques [6,20,22,25,321 in these systems.…”

Section: Introductionmentioning

confidence: 99%

Security of statistical databases

SchlöerJan¹

1980

ACM Trans. Database Syst.

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Statistical evaluation of databases which contain personal records may entail risks for the confidentiality of the individual records. The risk has increased with the availability of flexible interactive evaluation programs which permit the use of trackers, the most dangerous class of snooping tools known. A class of trackers, called union trackers, is described. They permit reconstruction of the entire database without supplementary knowledge and include the general tracker recently described as a special case. For many real statistical databases the overwhelming majority of definable sets of records will form trackers. For such databases a random search for a tracker is likely to succeed rapidly. Individual trackers are redefined and counted and their cardinalities are investigated. If there are n records in the database, then most individual trackers employ innocent cardinalities near n/3, making them difficult to detect. Disclosure with trackers usually requires little effort per retrieved data element.

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“…Dies setzt eine entsprechende Technik in Form eines Datenbank-Dialog-System [6,7] Bei den meisten dieser Beziehungen ist zu bedenken, dab sie durch Alter, Geschlecht, Ortsunterschiede oder durch andere Merkmale hervorgerufen oder tiberdeckt werden k6nnen.…”

Section: Obersicht Iiber Die Bestehenden Zusammenhgngeunclassified

Modell-Vorsorgeuntersuchung in zwei Betrieben

1976

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In the preceding articles a preventive screening model in two factories was described, the results were given and the exactitude of laboratory tests presented. In this paper the relations are studied between all the observed variables. Contingency-tables and the x2-statistic are used. For the 57 observed variables-(laboratory variables, e.g. triglicerides, cholesterol, glucose, uric acid, creatinine and questionnaire-items designed to screen for angina pectoris, myocardial infarction, claudicatio intermittens and bronchitis)-all possible contingency tables between two variables were calculated (1596 tables). The significant connections are reported in form of a hypothesis-matrix. There exists no statistical correlation between laboratory tests and questionnaire-items. The anamnestic questionnaire cannot be replaced by laboratory tests and vice versa. Nearly all items of the questionnaire are correlated. There are some correlations between laboratory tests, blood pressure and smoking habits.

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Bitstring Processing for Statistical Evaluation of Large Volumes of Medical Data

Cited by 6 publications

References 1 publication

A fast procedure for finding a tracker in a statistical database

A fast procedure for finding a tracker in a statistical database

Security of statistical databases

Modell-Vorsorgeuntersuchung in zwei Betrieben

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