Privacy sensitive estimation of digital resource access frequency

A system comprising:

• one or more computers;
• and
• one or more storage devices communicatively coupled to the one or more computers, wherein the one or more storage devices store instructions that, when executed by the one or more computers, cause the one or more computers to perform operations comprising:
• obtaining access data for a digital resource, wherein the access data comprises, for each time point in a sequence of time points over a time span, data identifying a set of users that accessed the digital resource at the time point;
• processing the access data to generate data defining a tree model, wherein the tree model comprises a set of nodes, and each node in the set of nodes is associated with:
• (i) a respective key for the node that specifies a plurality of time intervals in the time span that are represented by the node, and
• (ii) a respective value for the node that is based on a combination of a respective noise for the node with a respective number of users that satisfy a node-specific selection criterion based on the plurality of time intervals in the time span that are represented by the node;
• receiving a request to determine a number of users that accessed the digital resource at least a predefined number of times within a time window;
• and
• in response to the request:
• processing the tree model to generate an estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window, wherein generating the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window comprises:
• identifying one or more nodes of the tree model based on the time window;
• and
• generating the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window based on the respective values for the one or more identified nodes;
• and
• outputting the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window.

One or more non-transitory computer storage media storing instructions that when executed by one or more computers cause the one or more computers to perform operations comprising:

• obtaining access data for a digital resource, wherein the access data comprises, for each time point in a sequence of time points over a time span, data identifying a set of users that accessed the digital resource at the time point;
• processing the access data to generate data defining a tree model, wherein the tree model comprises a set of nodes, and each node in the set of nodes is associated with:
• (i) a respective key for the node that specifies a plurality of time intervals in the time span that are represented by the node, and
• (ii) a respective value for the node that is based on a combination of a respective noise for the node with a respective number of users that satisfy a node-specific selection criterion based on the plurality of time intervals in the time span that are represented by the node;
• receiving a request to determine a number of users that accessed the digital resource at least a predefined number of times within a time window;
• and
• in response to the request:
• processing the tree model to generate an estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window, wherein generating the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window comprises:
• identifying one or more nodes of the tree model based on the time window;
• and
• generating the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window based on the respective values for the one or more identified nodes;
• and
• outputting the estimate for the number of users that accessed the digital resource at least the predefined number of times within the time window.