TY - GEN
T1 - The frequent items problem, under polynomial decay, in the streaming model
AU - Feigenblat, Guy
AU - Itzhaki, Ofra
AU - Porat, Ely
PY - 2009
Y1 - 2009
N2 - We consider the problem of estimating the frequency count of data stream elements under polynomial decay functions. In these settings every element arrives in the stream is assigned with a time decreasing weight, using a non increasing polynomial function. Decay functions are used in applications where older data is less significant \ interesting \ reliable than recent data. We propose 3 poly-logarithmic algorithms for the problem. The first one, deterministic, uses O(1/ε2 log N (log log N + log U)) bits. The second one, probabilistic, uses O(1/ε2 log 1/εδ log N) bits and the third one, deterministic in the stochastic model, uses O(1/ε2 log N) bits. In addition we show that using additional additive error can improve, in some cases, the space bounds. This variant of the problem is important and has many applications. To our knowledge it was never studied before.
AB - We consider the problem of estimating the frequency count of data stream elements under polynomial decay functions. In these settings every element arrives in the stream is assigned with a time decreasing weight, using a non increasing polynomial function. Decay functions are used in applications where older data is less significant \ interesting \ reliable than recent data. We propose 3 poly-logarithmic algorithms for the problem. The first one, deterministic, uses O(1/ε2 log N (log log N + log U)) bits. The second one, probabilistic, uses O(1/ε2 log 1/εδ log N) bits and the third one, deterministic in the stochastic model, uses O(1/ε2 log N) bits. In addition we show that using additional additive error can improve, in some cases, the space bounds. This variant of the problem is important and has many applications. To our knowledge it was never studied before.
UR - http://www.scopus.com/inward/record.url?scp=70350676791&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-03784-9_26
DO - 10.1007/978-3-642-03784-9_26
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AN - SCOPUS:70350676791
SN - 3642037836
SN - 9783642037832
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 266
EP - 276
BT - String Processing and Information Retrieval - 16th International Symposium, SPIRE 2009, Proceedings
T2 - 16th International Symposium on String Processing and Information Retrieval, SPIRE 2009
Y2 - 25 August 2009 through 27 August 2009
ER -