Efficient stream sharing for multi-user sensor data collection

A method performed by a computing device, the method sharing at least one of data access, computation, or functional workload among multiple applications, the method comprising:

• locating a specification that includes an area over which data is requested;
• based at least in part on the area over which the data is requested, determining a data source location situated within the area;
• determining a data source that is currently streaming data or has persisted data or initiating another data source that is needed to fulfill a query;
• based at least in part on the determining or the initiating, constructing or employing a directed acyclic graph to obviate redundancy in a functional requirement imposed by the query and formulating a result directed to an application;
• and
• diverting data flowing from the data source or the another data source directly to the application, the diverting being based on a determination that the functional requirement imposed by the query is unique to the query.

A system comprising:

• a coordinator configured to:
• receive a first query requesting that a particular operation is applied to first data values from first data sources,
• receive a second query requesting that the particular operation is applied to second data values from second data sources,
• represent the first query using a first graph having:
• first leaf nodes representing the first data values from the first data sources, the first leaf nodes having an associated first signature representing that the first leaf nodes serve the first query, and
• first non-leaf nodes representing first computed values obtained by applying the particular operation to the first data values,
• represent the second query using a second graph having:
• second leaf nodes representing the second data values from the second data sources, the second leaf nodes having an associated second signature representing that the second leaf nodes serve the second query, and
• second non-leaf nodes representing second computed values obtained by applying the particular operation to the second data values,
• identify a subset of common data values from the first data values and the second data values by detecting common leaf nodes from the first leaf nodes and the second leaf nodes, wherein some individual first data values represented by remaining first leaf nodes are not part of the subset and some individual second data values represented by remaining second leaf nodes are not part of the subset,
• assign the common leaf nodes a new third signature while retaining the first signature for the remaining first leaf nodes and retaining the second signature for the remaining second leaf nodes, and
• combine the first graph and the second graph to create a combined graph, wherein, in the combined graph, the remaining first leaf nodes have the first signature, the remaining second leaf nodes have the second signature, and the common leaf nodes have the new third signature;
• and
• a computing device configured to execute the coordinator.

A method performed by a computing device, the method comprising:

• receiving a first query requesting that a particular operation is applied to first data values from first data sources,
• receiving a second query requesting that the particular operation is applied to second data values from second data sources,
• representing the first query using a first graph having:
• first leaf nodes representing the first data values from the first data sources, the first leaf nodes having an associated first signature representing that the first leaf nodes serve the first query, and
• first non-leaf nodes representing first computed values obtained by applying the particular operation to the first data values,
• representing the second query using a second graph having:
• second leaf nodes representing the second data values from the second data sources, the second leaf nodes having an associated second signature representing that the second leaf nodes serve the second query, and
• second non-leaf nodes representing second computed values obtained by applying the particular operation to the second data values,
• identifying a subset of common data values from the first data values and the second data values by detecting common leaf nodes from the first leaf nodes and the second leaf nodes, wherein some individual first data values represented by remaining first leaf nodes are not part of the subset and some individual second data values represented by remaining second leaf nodes are not part of the subset,
• assigning the common leaf nodes a third signature while retaining the first signature for the remaining first leaf nodes and retaining the second signature for the remaining second leaf nodes, and
• combining the first graph and the second graph to create a combined graph, wherein, in the combined graph, the remaining first leaf nodes have the first signature, the remaining second leaf nodes have the second signature, and the common leaf nodes have the third signature.