Online Metric Tracking and Smoothing

We consider the online smoothing problem , in which a tracker is required to maintain distance no more than Δ≥0 from a time-varying signal f while minimizing its own movement. The problem is determined by a metric space ( X , d ) with an associated cost function c :ℝ→ℝ. Given a signal f 1 , f 2 ,…∈...

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Vydáno v:	Algorithmica Ročník 68; číslo 1; s. 133 - 151
Hlavní autoři:	Chen, Sixia, Russell, Alexander
Médium:	Journal Article
Jazyk:	angličtina
Vydáno:	Boston Springer US 01.01.2014 Springer
Témata:	Algorithm Analysis and Problem Complexity Algorithmics. Computability. Computer arithmetics Algorithms Applied sciences Computer Science Computer science; control theory; systems Computer Systems Organization and Communication Networks Data Structures and Information Theory Exact sciences and technology Mathematics of Computing Theoretical computing Theory of Computation Online algorithms Randomized algorithms On line Tracking Proximity Metric space Fixed cost Competitiveness Algorithmics Online algorithm Randomized algorithm Time varying system Smoothing Metric Deterministic algorithms
ISSN:	0178-4617, 1432-0541
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Abstract	We consider the online smoothing problem , in which a tracker is required to maintain distance no more than Δ≥0 from a time-varying signal f while minimizing its own movement. The problem is determined by a metric space ( X , d ) with an associated cost function c :ℝ→ℝ. Given a signal f 1 , f 2 ,…∈ X the tracker is responsible for producing a sequence a 1 , a 2 ,… of elements of X that meet the proximity constraint: d ( f i , a i )≤Δ. To complicate matters, the tracker is on-line—the value a i may only depend on f 1 ,…, f i —and wishes to minimize the cost of his travels, ∑ c ( d ( a i , a i +1 )). We evaluate such tracking algorithms competitively, comparing this with the cost achieved by an optimal adversary apprised of the entire signal in advance. The problem was originally proposed by Yi and Zhang (In: Proceedings of the 20th annual ACM-SIAM symposium on discrete algorithms (SODA), pp. 1098–1107. ACM Press, New York, 2009 ), who considered the natural circumstance where the metric spaces are taken to be ℤ k with the ℓ 2 metric and the cost function is equal to 1 unless the distance is zero (thus the tracker pays a fixed cost for any nonzero motion). We begin by studying arbitrary metric spaces with the “pay if you move” metric of Yi and Zhang (In: Proceedings of the 20th annual ACM-SIAM symposium on discrete algorithms (SODA), pp. 1098–1107. ACM Press, New York, [ 2009 ]) described above and describe a natural randomized algorithm that achieves a O (log b Δ )-competitive ratio, where b Δ =max x ∈ X \| B Δ ( x )\| is the maximum number of points appearing in any ball of radius Δ. We show that this bound is tight. We then focus on the metric space ℤ with natural families of monotone cost functions c ( x )= x p for some p ≥0. We consider both the expansive case ( p ≥1) and the contractive case ( p <1), and show that the natural lazy algorithm performs well in the expansive case. In the contractive case, we introduce and analyze a novel deterministic algorithm that achieves a constant competitive ratio depending only on p . Finally, we observe that by slightly relaxing the guarantee provided by the tracker, one can obtain natural analogues of these algorithms that work in continuous metric spaces.
AbstractList	We consider the online smoothing problem , in which a tracker is required to maintain distance no more than Δ≥0 from a time-varying signal f while minimizing its own movement. The problem is determined by a metric space ( X , d ) with an associated cost function c :ℝ→ℝ. Given a signal f 1 , f 2 ,…∈ X the tracker is responsible for producing a sequence a 1 , a 2 ,… of elements of X that meet the proximity constraint: d ( f i , a i )≤Δ. To complicate matters, the tracker is on-line—the value a i may only depend on f 1 ,…, f i —and wishes to minimize the cost of his travels, ∑ c ( d ( a i , a i +1 )). We evaluate such tracking algorithms competitively, comparing this with the cost achieved by an optimal adversary apprised of the entire signal in advance. The problem was originally proposed by Yi and Zhang (In: Proceedings of the 20th annual ACM-SIAM symposium on discrete algorithms (SODA), pp. 1098–1107. ACM Press, New York, 2009 ), who considered the natural circumstance where the metric spaces are taken to be ℤ k with the ℓ 2 metric and the cost function is equal to 1 unless the distance is zero (thus the tracker pays a fixed cost for any nonzero motion). We begin by studying arbitrary metric spaces with the “pay if you move” metric of Yi and Zhang (In: Proceedings of the 20th annual ACM-SIAM symposium on discrete algorithms (SODA), pp. 1098–1107. ACM Press, New York, [ 2009 ]) described above and describe a natural randomized algorithm that achieves a O (log b Δ )-competitive ratio, where b Δ =max x ∈ X \| B Δ ( x )\| is the maximum number of points appearing in any ball of radius Δ. We show that this bound is tight. We then focus on the metric space ℤ with natural families of monotone cost functions c ( x )= x p for some p ≥0. We consider both the expansive case ( p ≥1) and the contractive case ( p <1), and show that the natural lazy algorithm performs well in the expansive case. In the contractive case, we introduce and analyze a novel deterministic algorithm that achieves a constant competitive ratio depending only on p . Finally, we observe that by slightly relaxing the guarantee provided by the tracker, one can obtain natural analogues of these algorithms that work in continuous metric spaces.
Author	Chen, Sixia Russell, Alexander
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Cites_doi	10.1137/1.9781611973068.119 10.1145/1921659.1921667 10.1016/0196-6774(91)90041-V 10.1007/11830924_12 10.1111/j.2517-6161.1958.tb00294.x
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Keywords	Online algorithms Randomized algorithms On line Tracking Proximity Metric space Fixed cost Competitiveness Algorithmics Online algorithm Randomized algorithm Time varying system Smoothing Metric Deterministic algorithms
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References	Smith (CR9) 1958; 20 Cormode, Garofalakis, Muthukrishnan, Rastogi (CR3) 2005 Cormode, Garofalakis (CR2) 2005 Yi, Zhang (CR10) 2009 Davis, Edmonds, Impagliazzo (CR5) 2006 Fiat, Karp, Luby, McGeoch, Sleator, Young (CR6) 1991; 12 Cormode, Muthukrishnan, Yi (CR4) 2011; 7 CR8 Keralapura, Cormode, Ramamirtham (CR7) 2006 Bienkowski, Schmid (CR1) 2010 9669_CR8 G. Cormode (9669_CR2) 2005 A. Fiat (9669_CR6) 1991; 12 M. Bienkowski (9669_CR1) 2010 G. Cormode (9669_CR4) 2011; 7 W.L. Smith (9669_CR9) 1958; 20 G. Cormode (9669_CR3) 2005 R. Keralapura (9669_CR7) 2006 S. Davis (9669_CR5) 2006 K. Yi (9669_CR10) 2009
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SubjectTerms	Algorithm Analysis and Problem Complexity Algorithmics. Computability. Computer arithmetics Algorithms Applied sciences Computer Science Computer science; control theory; systems Computer Systems Organization and Communication Networks Data Structures and Information Theory Exact sciences and technology Mathematics of Computing Theoretical computing Theory of Computation
Title	Online Metric Tracking and Smoothing
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