83 research outputs found
Estimating Entropy of Data Streams Using Compressed Counting
The Shannon entropy is a widely used summary statistic, for example, network
traffic measurement, anomaly detection, neural computations, spike trains, etc.
This study focuses on estimating Shannon entropy of data streams. It is known
that Shannon entropy can be approximated by Reenyi entropy or Tsallis entropy,
which are both functions of the p-th frequency moments and approach Shannon
entropy as p->1.
Compressed Counting (CC) is a new method for approximating the p-th frequency
moments of data streams. Our contributions include:
1) We prove that Renyi entropy is (much) better than Tsallis entropy for
approximating Shannon entropy.
2) We propose the optimal quantile estimator for CC, which considerably
improves the previous estimators.
3) Our experiments demonstrate that CC is indeed highly effective
approximating the moments and entropies. We also demonstrate the crucial
importance of utilizing the variance-bias trade-off
On Practical Algorithms for Entropy Estimation and the Improved Sample Complexity of Compressed Counting
Estimating the p-th frequency moment of data stream is a very heavily studied
problem. The problem is actually trivial when p = 1, assuming the strict
Turnstile model. The sample complexity of our proposed algorithm is essentially
O(1) near p=1. This is a very large improvement over the previously believed
O(1/eps^2) bound. The proposed algorithm makes the long-standing problem of
entropy estimation an easy task, as verified by the experiments included in the
appendix
Differentially Private Fractional Frequency Moments Estimation with Polylogarithmic Space
We prove that Fp sketch, a well-celebrated streaming algorithm for frequency moments estimation, is differentially private as is when p β (0, 1]. Fp sketch uses only polylogarithmic space, exponentially better than existing DP baselines and only worse than the optimal non-private baseline by a logarithmic factor. The evaluation shows that Fp sketch can achieve reasonable accuracy with differential privacy guarantee. The evaluation code is included in the supplementary material
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