System and method for determining the age of objects in the presence of unreliable clocks
First Claim
1. A computer-implemented method for determining an age of an object, comprising:
- at a computer system including one or more processors and memory storing one or more programs for execution by the one or more processors;
identifying a first index for a timestamp entry in a sequence of timestamps corresponding to a time at which an object was created, wherein the sequence of timestamps is generated by periodically storing a current timestamp reported by a clock of the computer system into the sequence of timestamps;
identifying at least one subsequence of timestamps from the sequence of timestamps having indexes for entries in the sequence of timestamps that are between the first index in the sequence of timestamps and a last index for a last timestamp entry in the sequence of timestamps, wherein the at least one subsequence of timestamps conforms to a function of a time interval between storage of consecutive current timestamps reported by clock of the computer system, wherein identifying the at least one subsequence of timestamps from the sequence of timestamps includes;
identifying a longest increasing subsequence of timestamps having indexes for timestamp entries that are between the first index in the sequence of timestamps and the last index for the last timestamp entry in the sequence of timestamps; and
identifying a plurality of consecutive sequences of timestamps from the longest increasing subsequence of timestamps, wherein a respective consecutive sequence of timestamps includes at least a predetermined number of timestamps, and wherein the time interval between consecutive timestamps in the respective consecutive sequence of timestamps is less than a predetermined factor of the time interval between storage of consecutive current timestamps reported by the clock of the computer system; and
determining an age of the object based on the at least one subsequence of timestamps.
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Accused Products
Abstract
A system and method for determining an age of an object is provided. A first index for a timestamp entry in a sequence of timestamps corresponding to a time at which an object was created is identified. At least one subsequence of timestamps from the sequence of timestamps having indexes for entries in the sequence of timestamps that are between the first index in the sequence of timestamps and a last index for a last timestamp entry in the sequence of timestamps is identified, wherein the at least one subsequence of timestamps conforms to a function of a time interval between storage of consecutive current timestamps reported by clock of the computer system. Timestamps from the sequence of timestamps that are not included in the at least one subsequence of timestamps are removed. An age of the object is determined based on the at least one subsequence of timestamps.
60 Citations
27 Claims
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1. A computer-implemented method for determining an age of an object, comprising:
at a computer system including one or more processors and memory storing one or more programs for execution by the one or more processors; identifying a first index for a timestamp entry in a sequence of timestamps corresponding to a time at which an object was created, wherein the sequence of timestamps is generated by periodically storing a current timestamp reported by a clock of the computer system into the sequence of timestamps; identifying at least one subsequence of timestamps from the sequence of timestamps having indexes for entries in the sequence of timestamps that are between the first index in the sequence of timestamps and a last index for a last timestamp entry in the sequence of timestamps, wherein the at least one subsequence of timestamps conforms to a function of a time interval between storage of consecutive current timestamps reported by clock of the computer system, wherein identifying the at least one subsequence of timestamps from the sequence of timestamps includes; identifying a longest increasing subsequence of timestamps having indexes for timestamp entries that are between the first index in the sequence of timestamps and the last index for the last timestamp entry in the sequence of timestamps; and identifying a plurality of consecutive sequences of timestamps from the longest increasing subsequence of timestamps, wherein a respective consecutive sequence of timestamps includes at least a predetermined number of timestamps, and wherein the time interval between consecutive timestamps in the respective consecutive sequence of timestamps is less than a predetermined factor of the time interval between storage of consecutive current timestamps reported by the clock of the computer system; and determining an age of the object based on the at least one subsequence of timestamps. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for determining an age of an object, comprising:
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one or more processors; memory; and one or more programs stored in the memory, the one or more programs comprising instructions to; identify a first index for a timestamp entry in a sequence of timestamps corresponding to a time at which an object was created, wherein the sequence of timestamps is generated by periodically storing a current timestamp reported by a clock of the computer system into the sequence of timestamps; identify at least one subsequence of timestamps from the sequence of timestamps having indexes for entries in the sequence of timestamps that are between the first index in the sequence of timestamps and a last index for a last timestamp entry in the sequence of timestamps, wherein the at least one subsequence of timestamps conforms to a function of a time interval between storage of consecutive current timestamps reported by clock of the computer system, wherein the instructions to identify the at least one subsequence of timestamps from the sequence of timestamps include instructions to; identify a longest increasing subsequence of timestamps having indexes for timestamp entries that are between the first index in the sequence of timestamps and the last index for the last timestamp entry in the sequence of timestamps; and identify a plurality of consecutive sequences of timestamps from the longest increasing subsequence of timestamps, wherein a respective consecutive sequence of timestamps includes at least a predetermined number of timestamps, and wherein the time interval between consecutive timestamps in the respective consecutive sequence of timestamps is less than a predetermined factor of the time interval between storage of consecutive current timestamps reported by the clock of the computer system; and determine an age of the object based on the at least one subsequence of timestamps. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A non-transitory computer readable storage medium storing one or more programs configured for execution by a computer, the one or more programs comprising instructions to:
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identify a first index for a timestamp entry in a sequence of timestamps corresponding to a time at which an object was created, wherein the sequence of timestamps is generated by periodically storing a current timestamp reported by a clock of the computer system into the sequence of timestamps; identify at least one subsequence of timestamps from the sequence of timestamps having indexes for entries in the sequence of timestamps that are between the first index in the sequence of timestamps and a last index for a last timestamp entry in the sequence of timestamps, wherein the at least one subsequence of timestamps conforms to a function of a time interval between storage of consecutive current timestamps reported by clock of the computer system, wherein the instructions to identify the at least one subsequence of timestamps from the sequence of timestamps include instructions to; identify a longest increasing subsequence of timestamps having indexes for timestamp entries that are between the first index in the sequence of timestamps and the last index for the last timestamp entry in the sequence of timestamps; and identify a plurality of consecutive sequences of timestamps from the longest increasing subsequence of timestamps, wherein a respective consecutive sequence of timestamps includes at least a predetermined number of timestamps, and wherein the time interval between consecutive timestamps in the respective consecutive sequence of timestamps is less than a predetermined factor of the time interval between storage of consecutive current timestamps reported by the clock of the computer system; and determine an age of the object based on the at least one subsequence of timestamps. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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Specification