sql-derivative-sensitivity-analyser_advanced
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sql-derivative-sensitivity-analyser_advanced [2018/11/26 11:43] alisa |
sql-derivative-sensitivity-analyser_advanced [2018/11/26 11:45] alisa |
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| === Defining norms for data tables === | === Defining norms for data tables === | ||
| - | A table T's norm is defined either in the text file ''T.nrm'' (if the analyzer is run from the command line), or in the text input window **table norm** that opens after clicking on a data object (if analysis is run from PLEAK UI). | + | A table T's norm is defined either in the text file ''T.nrm'' (if the analyzer is run from the command line), or in the text input window **table norm** that opens after clicking on a data object (if analysis is run from PLEAK web application). |
| The first two lines tell which rows (indexed starting from 0) and which columns (identified by corresponding attribute name) are treated as sensitive. We estimate change in the output when only the sensitive entries may change, and the non-sensitive entries remain the same. | The first two lines tell which rows (indexed starting from 0) and which columns (identified by corresponding attribute name) are treated as sensitive. We estimate change in the output when only the sensitive entries may change, and the non-sensitive entries remain the same. | ||
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| </code> | </code> | ||
| - | The line ''u = lp 2.0 latitude longitude;'' combines latitude and longitude to define Euclidean distance (i.e l<sub>2</sub>-norm). We may scale the distances, and 0.2 in the line ''z = scaleNorm 0.2 u;'' means that we conceal changes in location up to 1/0.2 = 5 units. Finally, ''return linf z;'' shows how the distance between the tables is computed from the distances between their rows, and ''linf'' means that we take the maximum row distance (i.e l<sub>∞</sub>-norm), so DP conceals the change even if all sensitive rows change by a unit. | + | The line ''u = lp 2.0 latitude longitude;'' combines latitude and longitude to define Euclidean distance (i.e l<sub>2</sub>-norm). We may scale the distances, and 0.2 in the line ''z = scaleNorm 0.2 u;'' means that we conceal changes in location up to 1 / 0.2 = 5 units. Finally, ''return linf z;'' shows how the distance between the tables is computed from the distances between their rows, and ''linf'' means that we take the maximum row distance (i.e l<sub>∞</sub>-norm), so DP conceals the change even if all sensitive rows change by a unit. |
| === Combined sensitivity === | === Combined sensitivity === | ||
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| </code> | </code> | ||
| - | Intuitively, this means that both types of changes are allowed. In this example, differential privacy conceals the facts that a row has been added or removed, as well as that the latitude or longitude have been changed by a unit. More precisely, we define the distance between two tables as a //table edit distance// (analogous to string edit distance) that takes combines the following operations: | + | Intuitively, this means that both types of changes are allowed. In this example, differential privacy conceals the facts that a row has been added or removed, as well as that the latitude or longitude have been changed by a unit. More precisely, we define the distance between two tables as a //table edit distance// (analogous to string edit distance) that uses the following operations: |
| * the cost of row insertion/deletion (defined by the line ''G:''). | * the cost of row insertion/deletion (defined by the line ''G:''). | ||
| * the cost of cell modification (defined by the line ''cols:'' and the possible extension). | * the cost of cell modification (defined by the line ''cols:'' and the possible extension). | ||
| Table edit distance is defined as the minimal cost of operations required to transform one table into the other. | Table edit distance is defined as the minimal cost of operations required to transform one table into the other. | ||
sql-derivative-sensitivity-analyser_advanced.txt · Last modified: 2019/12/13 16:54 by alisa
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